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+The Project Gutenberg EBook of Seasoning of Wood, by Joseph B. Wagner
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Seasoning of Wood
+
+Author: Joseph B. Wagner
+
+Release Date: September 12, 2008 [EBook #26598]
+
+Language: English
+
+Character set encoding: ISO-8859-1
+
+*** START OF THIS PROJECT GUTENBERG EBOOK SEASONING OF WOOD ***
+
+
+
+
+Produced by Jason Isbell, Irma Spehar and the Online
+Distributed Proofreading Team at https://www.pgdp.net
+
+
+
+
+
+                           SEASONING OF WOOD
+
+               A TREATISE ON THE NATURAL AND ARTIFICIAL
+                 PROCESSES EMPLOYED IN THE PREPARATION
+                      OF LUMBER FOR MANUFACTURE,
+                   WITH DETAILED EXPLANATIONS OF ITS
+                 USES, CHARACTERISTICS AND PROPERTIES
+
+
+                            _ILLUSTRATIONS_
+                                  BY
+                           JOSEPH B. WAGNER
+                         AUTHOR OF "COOPERAGE"
+
+
+                            [Illustration]
+
+
+                               NEW YORK
+                        D. VAN NOSTRAND COMPANY
+                             25 PARK PLACE
+                                 1917
+
+
+                          COPYRIGHT, 1917, BY
+                        D. VAN NOSTRAND COMPANY
+
+
+                          THE·PLIMPTON·PRESS
+                          NORWOOD·MASS·U·S·A
+
+
+
+
+                                PREFACE
+
+
+The seasoning and kiln-drying of wood is such an important process in
+the manufacture of woods that a need for fuller information regarding
+it, based upon scientific study of the behavior of various species at
+different mechanical temperatures, and under different drying
+processes is keenly felt. Everyone connected with the woodworking
+industry, or its use in manufactured products, is well aware of the
+difficulties encountered in properly seasoning or removing the
+moisture content without injury to the timber, and of its
+susceptibility to atmospheric conditions after it has been thoroughly
+seasoned. There is perhaps no material or substance that gives up its
+moisture with more resistance than wood does. It vigorously defies the
+efforts of human ingenuity to take away from it, without injury or
+destruction, that with which nature has so generously supplied it.
+
+In the past but little has been known of this matter further than the
+fact that wood contained moisture which had to be removed before the
+wood could be made use of for commercial purposes. Within recent
+years, however, considerable interest has been awakened among
+wood-users in the operation of kiln-drying. The losses occasioned in
+air-drying and improper kiln-drying, and the necessity for getting the
+material dry as quickly as possible after it has come from the saw, in
+order to prepare it for manufacturing purposes, are bringing about a
+realization of the importance of a technical knowledge of the subject.
+
+Since this particular subject has never before been represented by any
+technical work, and appears to have been neglected, it is hoped that
+the trade will appreciate the endeavor in bringing this book before
+them, as well as the difficulties encountered in compiling it, as it
+is the first of its kind in existence. The author trusts that his
+efforts will present some information that may be applied with
+advantage, or serve at least as a matter of consideration or
+investigation.
+
+In every case the aim has been to give the facts, and wherever a
+machine or appliance has been illustrated or commented upon, or the
+name of the maker has been mentioned, it has not been with the
+intention either of recommending or disparaging his or their work, but
+has been made use of merely to illustrate the text.
+
+The preparation of the following pages has been a work of pleasure to
+the author. If they prove beneficial and of service to his
+fellow-workmen he will have been amply repaid.
+
+                                                      THE AUTHOR.
+
+    September, 1917
+
+
+
+
+                               CONTENTS
+
+
+                               SECTION I
+
+                                TIMBER
+                                                                   PAGES
+
+Characteristics and Properties of Same--Structure
+of Wood--Properties of Wood--Classes of Trees                        1-7
+
+                              SECTION II
+
+                           CONIFEROUS TREES
+
+Wood of Coniferous Trees--Bark and Pith--Sapwood and Heartwood--The
+Annual or Yearly Ring--Spring- and Summer-Wood--Anatomical
+Structure--List of Important Coniferous Trees                       8-30
+
+                              SECTION III
+
+                          BROAD-LEAVED TREES
+
+Wood of Broad-leaved Trees--Minute Structure--List of Most
+Important Broad-leaved Trees--Red Gum--Range of Red Gum--Form
+of Red Gum--Tolerance of Red Gum--Its Demands upon Soil and
+Moisture--Reproduction of Red Gum--Second-growth Red Gum--Tupelo
+Gum--Uses of Tupelo Gum--Range of Tupelo Gum                       31-85
+
+                              SECTION IV
+
+            GRAIN, COLOR, ODOR, WEIGHT, AND FIGURE IN WOOD
+
+Different Grains of Wood--Color and Odor of Wood--Weight of
+Wood--Weight of Kiln-dried Wood of Different Species--Figure in
+Wood                                                               86-97
+
+                               SECTION V
+
+                            ENEMIES OF WOOD
+
+General Remarks--Ambrosia or Timber Beetles--Round-headed
+Borers--Flat-headed Borers--Timber Worms--Powder Post
+Borers--Conditions Favorable for Insect Injury--Crude
+Products--Round Timber with Bark on--How to Prevent
+Injury--Saplings--Stave, Heading, and Shingle Bolts--Unseasoned
+Products in the Rough--Seasoned Products in the Rough--Dry
+Cooperage Stock and Wooden Truss Hoops--Staves and Heads
+of Barrels Containing Alcoholic Liquids                           98-113
+
+                              SECTION VI
+
+                             WATER IN WOOD
+
+Distribution of Water in Wood--Seasonal Distribution of Water in
+Wood--Composition of Sap--Effects of Moisture on Wood--The
+Fibre-Saturation Point in Wood                                   114-118
+
+                              SECTION VII
+
+                           WHAT SEASONING IS
+
+What Seasoning Is--Difference Between Seasoned and Unseasoned
+Wood--Manner of Evaporation of Water--Absorption of Water
+by Dry Wood--Rapidity of Evaporation--Physical Properties
+that Influence Drying                                            119-127
+
+                             SECTION VIII
+
+                        ADVANTAGES OF SEASONING
+
+Advantages of Seasoning--Prevention of Checking and
+Splitting--Shrinkage of Wood--Expansion of Wood--Elimination of
+Stain and Mildew                                                 128-137
+
+                              SECTION IX
+
+                      DIFFICULTIES OF DRYING WOOD
+
+Difficulties of Drying Wood--Changes Rendering Drying
+Difficult--Losses Due to Improper Kiln-drying--Properties of
+Wood that Effect Drying--Unsolved Problems in Kiln-drying        138-144
+
+                               SECTION X
+
+                         HOW WOOD IS SEASONED
+
+Methods of Drying--Drying at Atmospheric Pressure--Drying Under
+Pressure and Vacuum--Impregnation Methods--Preliminary
+Treatments--Out-of-door Seasoning                                145-155
+
+                              SECTION XI
+
+                          KILN-DRYING OF WOOD
+
+Advantages of Kiln-drying over Air Drying--Physical Conditions
+Governing the Drying of Wood--Theory of Kiln-drying--Requirements
+in a Satisfactory Dry Kiln--Kiln-drying--Remarks--Underlying
+Principles--Objects of Kiln-drying--Conditions of Success--Different
+Treatments According to Kind--Temperature Depends--Air
+Circulation--Humidity--Kiln-drying--Pounds of Water Lost in Drying
+100 Pounds of Green Wood in the Kiln--Kiln-drying Gum--Preliminary
+Steaming--Final Steaming--Kiln-drying of Green Red Gum           156-184
+
+                              SECTION XII
+
+                          TYPES OF DRY KILNS
+
+Different types of Dry Kilns--The "Blower" or "Hot Blast" Dry
+Kiln--Operating the "Blower" or "Hot Blast" Dry Kiln--The
+"Pipe" or "Moist-Air" Dry Kiln--Operating the "Pipe" or
+"Moist-Air" Dry Kiln--Choice of Drying Method--Kilns of
+Different Types--The "Progressive" Dry Kiln--The "Apartment"
+Dry Kiln--The "Pocket" Dry Kiln--The "Tower" Dry Kiln--The
+"Box" Dry Kiln                                                   185-205
+
+                             SECTION XIII
+
+                         DRY KILN SPECIALTIES
+
+Kiln Cars and Method of Loading Same--The "Cross-wise" Piling
+Method--The "End-wise" Piling Method--The "Edge-wise"
+Piling Method--The Automatic Lumber Stacker--The Unstacker
+Car--Stave Piling--Shingle Piling--Stave Bolt Trucks--Different
+Types of Kiln Cars--Different Types of Transfer Cars--Dry Kiln
+Doors--Different Types of Kiln Door Carriers                     206-236
+
+                              SECTION XIV
+
+                   HELPFUL APPLIANCES IN KILN DRYING
+
+The Humidity Diagram--Examples of Use--The Hygrodeik--The
+Recording Hygrometer--The Registering Hygrometer--The
+Recording Thermometer--The Registering Thermometer--The
+Recording Steam Gauge--The Troemroid Scalometer--Test
+Samples--Weighing--Examples of Use--Records of Moisture
+Content--Saw Mills--Factories--The Electric Heater               237-250
+
+                              SECTION XV
+
+Bibliography--Glossary--Index of Latin Names--Index of Common
+Names                                                            251-257
+
+
+
+
+                         LIST OF ILLUSTRATIONS
+
+ FIG.                                                               PAGE
+
+ 1. Board of pine                                                     13
+ 2. Wood of spruce                                                    14
+ 3. Group of fibres from pine wood                                    15
+ 4. Block of oak                                                      31
+ 5. Board of oak                                                      32
+ 6. Cross-section of oak highly magnified                             32
+ 7. Highly magnified fibres of wood                                   33
+ 8. Isolated fibres and cells of wood                                 34
+ 9. Cross-section of basswood                                         35
+10. A large red gum                                                   52
+11. A tupelo gum slough                                               53
+12. Second growth red gum                                             57
+13. A cypress slough in dry season                                    58
+14. A large cottonwood                                                78
+15. Spiral grain in wood                                              87
+16. Alternating spiral grain in cypress                               87
+17. Wavy grain in beech                                               88
+18. Section of wood showing position of the grain at base of limb     89
+19. Cross-section of a group of wood fibres                           91
+20. Isolated fibres of wood                                           91
+21. Orientation of wood samples                                       93
+22. Work of ambrosia beetles in tulip or yellow poplar               100
+23. Work of ambrosia beetles in oak                                  100
+24. Work of round-headed and flat-headed borers in pine              102
+25. Work of timber worms in oak                                      103
+26. Work of powder post borers in hickory poles                      104
+27. Work of powder post borers in hickory poles                      104
+28. Work of powder post borers in hickory handles                    105
+29. Work of round-headed borers in white pine staves                 111
+30. U. S. Forest Service humidity controlled dry kiln                161
+31. Section through moist-air dry kiln                               189
+32. Live steam single pipe heating apparatus                         190
+33. Live steam double pipe heating apparatus                         191
+34. Vertical Pipe heating apparatus                                  193
+35. Progressive dry kilns                                            197
+36. Apartment dry kilns                                              199
+37. Pocket dry kilns                                                 201
+38. Tower dry kiln                                                   203
+39. Box dry kiln                                                     205
+40. Edge-wise method of piling                                       206
+41. Edge-wise method of piling                                       207
+42. Automatic lumber stacker                                         208
+43. Automatic lumber stacker                                         208
+44. Battery of three automatic lumber stackers                       209
+45. Battery of three automatic lumber stackers                       209
+46. Lumber loaded edge-wise on kiln truck                            210
+47. The lumber unstacker                                             211
+48. The lumber unstacker car                                         211
+49. Method of piling veneer on edge                                  212
+50. Kiln truck loaded cross-wise of kiln                             213
+51. Kiln truck loaded cross-wise of kiln                             214
+52. Kiln truck loaded end-wise of kiln                               214
+53. Kiln truck loaded end-wise of kiln                               215
+54. Method of piling staves on kiln truck                            216
+55. Method of piling staves on kiln truck                            216
+56. Method of piling tub or pail staves on kiln truck                217
+57. Method of piling bundled staves on kiln truck                    217
+58. Method of piling shingles on kiln truck                          218
+59. Method of piling shingles on kiln truck                          218
+60. Method of piling shingles on kiln truck                          219
+61. Kiln truck designed for loose pail staves                        219
+62. Kiln truck designed for handling short stock                     221
+63. Stave bolt truck                                                 221
+64. Stave bolt truck                                                 222
+65. Stave bolt truck                                                 222
+66. Stave bolt truck                                                 223
+67. Stave bolt truck                                                 223
+68. Stave bolt truck                                                 224
+69. Regular 3-rail transfer car                                      224
+70. Regular 3-rail transfer car                                      225
+71. Special 4-rail transfer car                                      225
+72. Regular 2-rail transfer car                                      225
+73. Regular 2-rail transfer car                                      226
+74. Underslung type 3-rail transfer car                              226
+75. Underslung type 2-rail transfer car                              226
+76. Flexible type 2-rail transfer car                                227
+77. Regular transfer car for stave bolt trucks                       228
+78. Regular transfer car for stave bolt trucks                       228
+79. Special transfer car for stave bolt trucks                       228
+80. Regular channel iron kiln truck for cross-wise piling            229
+81. Regular channel iron kiln truck for cross-wise piling            229
+82. Regular channel iron kiln truck for end-wise piling              230
+83. Special channel iron kiln truck for end-wise piling              230
+84. Regular dolly kiln truck for end-wise piling                     230
+85. Asbestos-lined kiln door                                         231
+86. Twin door carrier with door loaded                               232
+87. Twin door carrier for doors 18 to 35 feet wide                   232
+88. Kiln door carrier                                                233
+89. Kiln door construction                                           234
+90. Kiln door construction                                           235
+91. Kiln door construction                                           235
+92. Kiln door construction                                           236
+93. The Humidity diagram                                  _facing_   237
+94. The hygrodeik                                                    242
+95. The recording hygrometer                                         243
+96. The registering hygrometer                                       244
+97. The recording thermometer                                        245
+98. The registering thermometer                                      246
+99. The recording steam gauge                                        246
+100. The troemroid scalometer                                        247
+101. The electric heater                                             250
+
+
+
+
+                           SEASONING OF WOOD
+
+
+
+
+                               SECTION I
+
+                                TIMBER
+
+                    Characteristics and Properties
+
+
+Timber was probably one of the earliest, if not the earliest, of
+materials used by man for constructional purposes. With it he built
+for himself a shelter from the elements; it provided him with fuel and
+oft-times food, and the tree cut down and let across a stream formed
+the first bridge. From it, too, he made his "dug-out" to travel along
+and across the rivers of the district in which he dwelt; so on down
+through the ages, for shipbuilding and constructive purposes, timber
+has continued to our own time to be one of the most largely used of
+nature's products.
+
+Although wood has been in use so long and so universally, there still
+exists a remarkable lack of knowledge regarding its nature, not only
+among ordinary workmen, but among those who might be expected to know
+its properties. Consequently it is often used in a faulty and wasteful
+manner. Experience has been almost the only teacher, and
+theories--sometimes right, sometimes wrong--rather than well
+substantiated facts, lead the workman.
+
+One reason for this imperfect knowledge lies in the fact that wood is
+not a homogeneous material, but a complicated structure, and so
+variable, that one piece will behave very differently from another,
+although cut from the same tree. Not only does the wood of one species
+differ from that of another, but the butt cut differs from that of the
+top log, the heartwood from the sapwood; the wood of quickly-grown
+sapling of the abandoned field, from that of the slowly-grown, old
+monarch of the forest. Even the manner in which the tree was cut and
+kept influences its behavior and quality. It is therefore extremely
+difficult to study the material for the purpose of establishing
+general laws.
+
+The experienced woodsman will look for straight-grained, long-fibred
+woods, with the absence of disturbing resinous and coloring matter,
+knots, etc., and will quickly distinguish the more porous red or black
+oaks from the less porous white species, _Quercus alba_. That the
+inspection should have regard to defects and unhealthy conditions
+(often indicated by color) goes without saying, and such inspection is
+usually practised. That knots, even the smallest, are defects, which
+for some uses condemn the material entirely, need hardly be mentioned.
+But that "season-checks," even those that have closed by subsequent
+shrinkage, remain elements of weakness is not so readily appreciated;
+yet there cannot be any doubt of this, since these, the intimate
+connections of the wood fibres, when once interrupted are never
+reestablished.
+
+Careful woods-foremen and manufacturers, therefore, are concerned as
+to the manner in which their timber is treated after the felling, for,
+according to the more or less careful seasoning of it, the season
+checks--not altogether avoidable--are more or less abundant.
+
+There is no country where wood is more lavishly used or criminally
+neglected than in the United States, and none in which nature has more
+bountifully provided for all reasonable requirements.
+
+In the absence of proper efforts to secure reproduction, the most
+valuable kinds are rapidly being decimated, and the necessity of a
+more rational and careful use of what remains is clearly apparent. By
+greater care in selection, however, not only will the duration of the
+supply be extended, but more satisfactory results will accrue from its
+practice.
+
+There are few more extensive and wide-reaching subjects on which to
+treat than timber, which in this book refers to dead timber--the
+timber of commerce--as distinct from the living tree. Such a great
+number of different kinds of wood are now being brought from various
+parts of the world, so many new kinds are continually being added, and
+the subject is more difficult to explain because timber of practically
+the same character which comes from different localities goes under
+different names, that if one were always to adhere to the botanical
+name there would be less confusion, although even botanists differ in
+some cases as to names. Except in the cases of the older and better
+known timbers, one rarely takes up two books dealing with timber and
+finds the botanical names the same; moreover, trees of the same
+species may produce a much poorer quality of timber when obtained from
+different localities in the same country, so that botanical knowledge
+will not always allow us to dispense with other tests.
+
+The structure of wood affords the only reliable means of
+distinguishing the different kinds. Color, weight, smell, and other
+appearances, which are often direct or indirect results of structure,
+may be helpful in this distinction, but cannot be relied upon
+entirely. Furthermore, structure underlies nearly all the technical
+properties of this important product, and furnishes an explanation why
+one piece differs in these properties from another. Structure explains
+why oak is heavier, stronger, and tougher than pine; why it is harder
+to saw and plane, and why it is so much more difficult to season
+without injury. From its less porous structure alone it is evident
+that a piece of young and thrifty oak is stronger than the porous wood
+of an old or stunted tree, or that a Georgia or long-leaf pine excels
+white pine in weight and strength.
+
+Keeping especially in mind the arrangement and direction of the fibres
+of wood, it is clear at once why knots and "cross-grain" interfere
+with the strength of timber. It is due to the structural peculiarities
+that "honeycombing" occurs in rapid seasoning, that checks or cracks
+extend radially and follow pith rays, that tangent or "bastard" cut
+stock shrinks and warps more than that which is quarter-sawn. These
+same peculiarities enable oak to take a better finish than basswood or
+coarse-grained pine.
+
+
+                           Structure of Wood
+
+The softwoods are made up chiefly of tracheids, or vertical cells
+closed at the ends, and of the relatively short parenchyma cells of
+the medullary rays which extend radially from the heart of the tree.
+The course of the tracheids and the rays are at right angles to each
+other. Although the tracheids have their permeable portions or pits in
+their walls, liquids cannot pass through them with the greatest ease.
+The softwoods do not contain "pores" or vessels and are therefore
+called "non-porous" woods.
+
+The hardwoods are not so simple in structure as softwoods. They
+contain not only rays, and in many cases tracheids, but also
+thick-walled cells called fibres and wood parenchyma for the storage
+of such foods as starches and sugars. The principal structural
+features of the hardwoods are the pores or vessels. These are long
+tubes, the segments of which are made up of cells which have lost
+their end walls and joined end to end, forming continuous "pipe lines"
+from the roots to the leaves in the tree. Since they possess pores or
+vessels, the hardwoods are called "porous" woods.
+
+Red oak is an excellent example of a porous wood. In white oak the
+vessels of the heartwood especially are closed, very generally by
+ingrowths called tyloses. This probably explains why red oak dries
+more easily and rapidly than white oak.
+
+The red and black gums are perhaps the simplest of the hardwoods in
+structure. They are termed "diffuse porous" woods because of the
+numerous scattered pores they contain. They have only vessels, wood
+fibres, and a few parenchyma cells. The medullary rays, although
+present, are scarcely visible in most instances. The vessels are in
+many cases open, and might be expected to offer relatively little
+resistance to drying.
+
+
+                          Properties of Wood
+
+Certain general properties of wood may be discussed briefly. We know
+that wood substance has the property of taking in moisture from the
+air until some balance is reached between the humidity of the air and
+the moisture in the wood. This moisture which goes into the cell walls
+hygroscopic moisture, and the property which the wood substance has of
+taking on hygroscopic moisture is termed hygroscopicity. Usually wood
+contains not only hygroscopic moisture but also more or less free
+water in the cell cavities. Especially is this true of sapwood. The
+free water usually dries out quite rapidly with little or no shrinkage
+or other physical change.
+
+In certain woods--for example, _Eucalyptus globulus_ and possibly some
+oaks--shrinkage begins almost at once, thus introducing a factor at
+the very start of the seasoning process which makes these woods very
+refractory.
+
+The cell walls of some species, including the two already mentioned,
+such as Western red cedar and redwood, become soft and plastic when
+hot and moist. If the fibres are hot enough and very wet, they are not
+strong enough to withstand the resulting force of the atmospheric
+pressure and the tensile force exerted by the departing free water,
+and the result is that the cells actually collapse.
+
+In general, however, the hygroscopic moisture necessary to saturate
+the cell walls is termed the "fibre saturation point." This amount has
+been found to be from 25 to 30 per cent of the dry wood weight. Unlike
+_Eucalyptus globulus_ and certain oaks, the gums do not begin to
+shrink until the moisture content has been reduced to about 30 per
+cent of the dry wood weight. These woods are not subject to collapse,
+although their fibres become very plastic while hot and moist.
+
+Upon the peculiar properties of each wood depends the difficulty or
+ease of the seasoning process.
+
+
+                           Classes of Trees
+
+The timber of the United States is furnished by three well-defined
+classes of trees: (1) The needle-leaved, naked-seeded conifers, such
+as pine, cedar, etc., (2) the broad-leaved trees such as oak poplar,
+etc., and (3) to an inferior extent by the (one-seed leaf) palms,
+yuccas, and their allies, which are confined to the most southern
+parts of the country.
+
+Broad-leaved trees are also known as deciduous trees, although,
+especially in warm countries, many of them are evergreen, while the
+needle-leaved trees (conifers) are commonly termed "evergreens,"
+although the larch, bald cypress, and others shed their leaves every
+fall, and even the names "broad-leaved" and "coniferous," though
+perhaps the most satisfactory, are not at all exact, for the conifer
+"ginkgo" has broad leaves and bears no cones.
+
+Among the woodsmen, the woods of broad-leaved trees are known as
+"hardwoods," though poplar is as soft as pine, and the "coniferous
+woods" are known as "softwoods," notwithstanding the fact that yew
+ranks high in hardness even when compared with "hardwoods."
+
+Both in the number of different kinds of trees or species and still
+more in the importance of their product, the conifers and broad-leaved
+trees far excel the palms and their relatives.
+
+In the manner of their growth both the conifers and broad-leaved trees
+behave alike, adding each year a new layer of wood, which covers the
+old wood in all parts of the stem and limbs. Thus the trunk continues
+to grow in thickness throughout the life of the tree by additions
+(annual rings), which in temperate climates are, barring accidents,
+accurate records of the tree. With the palms and their relatives the
+stem remains generally of the same diameter, the tree of a hundred
+years old being as thick as it was at ten years, the growth of these
+being only at the top. Even where a peripheral increase takes place,
+as in the yuccas, the wood is not laid on in well-defined layers for
+the structure remains irregular throughout. Though alike in the manner
+of their growth, and therefore similar in their general make-up,
+conifers and broad-leaved trees differ markedly in the details of
+their structure and the character of their wood.
+
+The wood of all conifers is very simple in its structure, the fibres
+composing the main part of the wood all being alike and their
+arrangement regular. The wood of the broad-leaved trees is complex in
+structure; it is made up of different kinds of cells and fibres and
+lacks the regularity of arrangement so noticeable in the conifers.
+This difference is so great that in a study of wood structure it is
+best to consider the two kinds separately.
+
+In this country the great variety of woods, and especially of useful
+woods, often makes the mere distinction of the kind or species of tree
+most difficult. Thus there are at least eight pines of the thirty-five
+native ones in the market, some of which so closely resemble each
+other in their minute structure that one can hardly tell them apart,
+and yet they differ in quality and are often mixed or confounded in
+the trade. Of the thirty-six oaks, of which probably not less than six
+or eight are marketed, we can readily recognize by means of their
+minute anatomy at least two tribes--the white and black oaks. The same
+is true of the eleven kinds of hickory, the six kinds of ash, etc.,
+etc.
+
+The list of names of all trees indigenous to the United States, as
+enumerated by the United States Forest Service, is 495 in number, the
+designation of "tree" being applied to all woody plants which produce
+naturally in their native habitat one main, erect stem, bearing a
+definite crown, no matter what size they attain.
+
+Timber is produced only by the Spermatophyta, or seed-bearing plants,
+which are subdivided into the Gymnosperms (conifers), and Angiosperms
+(broad-leaved). The conifer or cone-bearing tree, to which belong the
+pines, larches, and firs, is one of the three natural orders of
+Gymnosperms. These are generally classed as "softwoods," and are more
+extensively scattered and more generally used than any other class of
+timber, and are simple and regular in structure. The so-called
+"hardwoods" are "Dicotyledons" or broad-leaved trees, a subdivision of
+the Angiosperms. They are generally of slower growth, and produce
+harder timber than the conifers, but not necessarily so. Basswood,
+poplar, sycamore, and some of the gums, though classed with the
+hardwoods, are not nearly as hard as some of the pines.
+
+
+
+
+                              SECTION II
+
+                           CONIFEROUS TREES
+
+                     WOOD OF THE CONIFEROUS TREES
+
+
+Examining a smooth cross-section or end face of a well-grown log of
+Georgia pine, we distinguish an envelope of reddish, scaly bark, a
+small, whitish pith at the center, and between these the wood in a
+great number of concentric rings.
+
+
+                             Bark and Pith
+
+The bark of a pine stem is thickest and roughest near the base,
+decreases rapidly in thickness from one to one-half inches at the
+stump to one-tenth inch near the top of the tree, and forms in general
+about ten to fifteen per cent of the entire trunk. The pith is quite
+thick, usually one-eighth to one-fifth inch in southern species,
+though much less so in white pine, and is very thin, one-fifteenth to
+one twenty-fifth inch in cypress, cedar, and larch.
+
+In woods with a thick pith, the pith is finest at the stump, grows
+rapidly thicker toward the top, and becomes thinner again in the crown
+and limbs, the first one to five rings adjoining it behaving
+similarly.
+
+What is called the pith was once the seedling tree, and in many of the
+pines and firs, especially after they have been seasoning for a good
+while, this is distinctly noticeable in the center of the log, and
+detaches itself from the surrounding wood.
+
+
+                           Sap and Heartwood
+
+Wood is composed of duramen or heartwood, and alburnum or sapwood, and
+when dry consists approximately of 49 per cent by weight of carbon, 6
+per cent of hydrogen, 44 per cent of oxygen, and 1 per cent of ash,
+which is fairly uniform for all species. The sapwood is the external
+and youngest portion of the tree, and often constitutes a very
+considerable proportion of it. It lies next the bark, and after a
+course of years, sometimes many, as in the case of oaks, sometimes
+few, as in the case of firs, it becomes hardened and ultimately forms
+the duramen or heartwood. Sapwood is generally of a white or light
+color, almost invariably lighter in color than the heartwood, and is
+very conspicuous in the darker-colored woods, as for instance the
+yellow sapwood of mahogany and similiar colored woods, and the reddish
+brown heartwood; or the yellow sapwood of _Lignum-vitae_ and the dark
+green heartwood. Sapwood forms a much larger proportion of some trees
+than others, but being on the outer circumference it always forms a
+large proportion of the timber, and even in sound, hard pine will be
+from 40 per cent to 60 per cent of the tree and in some cases much
+more. It is really imperfect wood, while the duramen or heartwood is
+the perfect wood; the heartwood of the mature tree was the sapwood of
+its earlier years. Young trees when cut down are almost all sapwood,
+and practically useless as good, sound timber; it is, however, through
+the sapwood that the life-giving juices which sustain the tree arise
+from the soil, and if the sapwood be cut through, as is done when
+"girdling," the tree quickly dies, as it can derive no further
+nourishment from the soil. Although absolutely necessary to the
+growing tree, sapwood is often objectionable to the user, as it is the
+first part to decay. In this sapwood many cells are active, store up
+starch, and otherwise assist in the life processes of the tree,
+although only the last or outer layer of cells forms the growing part,
+and the true life of the tree.
+
+The duramen or heartwood is the inner, darker part of the log. In the
+heartwood all the cells are lifeless cases, and serve only the
+mechanical function of keeping the tree from breaking under its own
+great weight or from being laid low by the winds. The darker color of
+the heartwood is due to infiltration of chemical substances into the
+cell walls, but the cavities of the cells in pine are not filled up,
+as is sometimes believed, nor do their walls grow thicker, nor are the
+walls any more liquified than in the sapwood.
+
+Sapwood varies in width and in the number of rings which it contains
+even in different parts of the same tree. The same year's growth which
+is sapwood in one part of a disk may be heartwood in another. Sapwood
+is widest in the main part of the stem and often varies within
+considerable limits and without apparent regularity. Generally, it
+becomes narrower toward the top and in the limbs, its width varying
+with the diameter, and being the least in a given disk on the side
+which has the shortest radius. Sapwood of old and stunted pines is
+composed of more rings than that of young and thrifty specimens. Thus
+in a pine two hundred and fifty years old a layer of wood or an annual
+ring does not change from sapwood to heartwood until seventy or eighty
+years after it is formed, while in a tree one hundred years old or
+less it remains sapwood only from thirty to sixty years.
+
+The width of the sapwood varies considerably for different kinds of
+pine. It is small for long-leaf and white pine and great for loblolly
+and Norway pines. Occupying the peripheral part of the trunk, the
+proportion which it forms of the entire mass of the stem is always
+great. Thus even in old long-leaf pines, the sapwood forms 40 per cent
+of the merchantable log, while in the loblolly and in all young trees
+the sapwood forms the bulk of the wood.
+
+
+                      The Annual or Yearly Rings
+
+The concentric annual or yearly rings which appear on the end face of
+a log are cross-sections of so many thin layers of wood. Each such
+layer forms an envelope around its inner neighbor, and is in turn
+covered by the adjoining layer without, so that the whole stem is
+built up of a series of thin, hollow cylinders, or rather cones.
+
+A new layer of wood is formed each season, covering the entire stem,
+as well as all the living branches. The thickness of this layer or the
+width of the yearly ring varies greatly in different trees, and also
+in different parts of the same tree.
+
+In a normally-grown, thrifty pine log the rings are widest near the
+pith, growing more and more narrow toward the bark. Thus the central
+twenty rings in a disk of an old long-leaf pine may each be one-eighth
+to one-sixth inch wide, while the twenty rings next to the bark may
+average only one-thirtieth inch.
+
+In our forest trees, rings of one-half inch in width occur only near
+the center in disks of very thrifty trees, of both conifers and
+hardwoods. One-twelfth inch represents good, thrifty growth, and the
+minimum width of one two hundred inch is often seen in stunted spruce
+and pine. The average width of rings in well-grown, old white pine
+will vary from one-twelfth to one-eighteenth inch, while in the slower
+growing long-leaf pine it may be one twenty-fifth to one-thirtieth of
+an inch. The same layer of wood is widest near the stump in very
+thrifty young trees, especially if grown in the open park; but in old
+forest trees the same year's growth is wider at the upper part of the
+tree, being narrowest near the stump, and often also near the very tip
+of the stem. Generally the rings are widest near the center, growing
+narrower toward the bark.
+
+In logs from stunted trees the order is often reversed, the interior
+rings being thin and the outer rings widest. Frequently, too, zones or
+bands of very narrow rings, representing unfavorable periods of
+growth, disturb the general regularity.
+
+Few trees, even among pines, furnish a log with truly circular
+cross-section. Usually it is an oval, and at the stump commonly quite
+an irregular figure. Moreover, even in very regular or circular disks
+the pith is rarely in the center, and frequently one radius is
+conspicuously longer than its opposite, the width of some rings, if
+not all, being greater on one side than on the other. This is nearly
+always so in the limbs, the lower radius exceeding the upper. In
+extreme cases, especially in the limbs, a ring is frequently
+conspicuous on one side, and almost or entirely lost to view on the
+other. Where the rings are extremely narrow, the dark portion of the
+ring is often wanting, the color being quite uniform and light. The
+greater regularity or irregularity of the annual rings has much to do
+with the technical qualities of the timber.
+
+
+                        Spring- and Summer-Wood
+
+Examining the rings more closely, it is noticed that each ring is made
+up of an inner, softer, light-colored and an outer, or peripheral,
+firmer and darker-colored portion. Being formed in the forepart of the
+season, the inner, light-colored part is termed spring-wood, the
+outer, darker-portioned being the summer-wood of the ring. Since the
+latter is very heavy and firm it determines to a very large extent the
+weight and strength of the wood, and as its darker color influences
+the shade of color of the entire piece of wood, this color effect
+becomes a valuable aid in distinguishing heavy and strong from light
+and soft pine wood.
+
+In most hard pines, like the long-leaf, the dark summer-wood appears
+as a distinct band, so that the yearly ring is composed of two sharply
+defined bands--an inner, the spring-wood, and an outer, the
+summer-wood. But in some cases, even in hard pines, and normally in
+the woods of white pines, the spring-wood passes gradually into the
+darker summer-wood, so that a darkly defined line occurs only where
+the spring-wood of one ring abuts against the summer-wood of its
+neighbor. It is this clearly defined line which enables the eye to
+distinguish even the very narrow lines in old pines and spruces.
+
+In some cases, especially in the trunks of Southern pines, and
+normally on the lower side of pine limbs, there occur dark bands of
+wood in the spring-wood portion of the ring, giving rise to false
+rings, which mislead in a superficial counting of rings. In the disks
+cut from limbs these dark bands often occupy the greater part of the
+ring, and appear as "lunes," or sickle-shaped figures. The wood of
+these dark bands is similar to that of the true summer-wood. The cells
+have thick walls, but usually the compressed or flattened form.
+Normally, the summer-wood forms a greater proportion of the rings in
+the part of the tree formed during the period of thriftiest growth. In
+an old tree this proportion is very small in the first two to five
+rings about the pith, and also in the part next to the bark, the
+intermediate part showing a greater proportion of summer-wood. It is
+also greatest in a disk taken from near the stump, and decreases
+upward in the stem, thus fully accounting for the difference in weight
+and firmness of the wood of these different parts.
+
+    [Illustration: Fig. 1. Board of Pine. CS, cross-section; RS,
+    radial section; TS, tangential section; _sw_, summer-wood;
+    _spw_, spring-wood.]
+
+In the long-leaf pine the summer-wood often forms scarcely ten per
+cent of the wood in the central five rings; forty to fifty per cent of
+the next one hundred rings, about thirty per cent of the next fifty,
+and only about twenty per cent in the fifty rings next to the bark. It
+averages forty-five per cent of the wood of the stump and only
+twenty-four per cent of that of the top.
+
+Sawing the log into boards, the yearly rings are represented on the
+board faces of the middle board (radial sections) by narrow parallel
+strips (see Fig. 1), an inner, lighter stripe and its outer, darker
+neighbor always corresponding to one annual ring.
+
+On the faces of the boards nearest the slab (tangential or bastard
+boards) the several years' growth should also appear as parallel, but
+much broader stripes. This they do if the log is short and very
+perfect. Usually a variety of pleasing patterns is displayed on the
+boards, depending on the position of the saw cut and on the regularity
+of growth of the log (see Fig. 1). Where the cut passes through a
+prominence (bump or crook) of the log, irregular, concentric circlets
+and ovals are produced, and on almost all tangent boards arrow or
+V-shaped forms occur.
+
+
+                         Anatomical Structure
+
+Holding a well-smoothed disk or cross-section one-eighth inch thick
+toward the light, it is readily seen that pine wood is a very porous
+structure. If viewed with a strong magnifier, the little tubes,
+especially in the spring-wood of the rings, are easily distinguished,
+and their arrangement in regular, straight, radial rows is apparent.
+
+    [Illustration: Fig. 2. Wood of Spruce. 1, natural size; 2,
+    small part of one ring magnified 100 times. The vertical
+    tubes are wood fibres, in this case all "tracheids." _m_,
+    medullary or pith ray; _n_, transverse tracheids of ray; _a_,
+    _b_, and _c_, bordered pits of the tracheids, more enlarged.]
+
+Scattered through the summer-wood portion of the rings, numerous
+irregular grayish dots (the resin ducts) disturb the uniformity and
+regularity of the structure. Magnified one hundred times, a piece of
+spruce, which is similar to pine, presents a picture like that shown
+in Fig. 2. Only short pieces of the tubes or cells of which the wood
+is composed are represented in the picture. The total length of these
+fibres is from one-twentieth to one-fifth inch, being the smallest
+near the pith, and is fifty to one hundred times as great as their
+width (see Fig. 3). They are tapered and closed at their ends,
+polygonal or rounded and thin-walled, with large cavity, lumen or
+internal space in the spring-wood, and thick-walled and flattened
+radially, with the internal space or lumen much reduced in the
+summer-wood (see right-hand portion of Fig. 2). This flattening,
+together with the thicker walls of the cells, which reduces the lumen,
+causes the greater firmness and darker color of the summer-wood.
+There is more material in the same volume. As shown in the figure, the
+tubes, cells or "tracheids" are decorated on their walls by
+circlet-like structures, the "bordered pits," sections of which are
+seen more magnified as _a_, _b_, and _c_, Fig. 2. These pits are in
+the nature of pores, covered by very thin membranes, and serve as
+waterways between the cells or tracheids. The dark lines on the side
+of the smaller piece (1, Fig. 2) appear when magnified (in 2, Fig. 2)
+as tiers of eight to ten rows of cells, which run radially (parallel
+to the rows of tubes or tracheids), and are seen as bands on the
+radial face and as rows of pores on the tangential face. These bands
+or tiers of cell rows are the medullary rays or pith rays, and are
+common to all our lumber woods.
+
+In the pines and other conifers they are quite small, but they can
+readily be seen even without a magnifier. If a radial surface of
+split-wood (not smoothed) is examined, the entire radial face will be
+seen almost covered with these tiny structures, which appear as fine
+but conspicuous cross-lines. As shown in Fig. 2, the cells of the
+medullary or pith are smaller and very much shorter than the wood
+fibre or tracheids, and their long axis is at right angles to that of
+the fiber.
+
+    [Illustration: Fig. 3. Group of Fibres from Pine Wood. Partly
+    schematic. The little circles are "border pits" (see Fig. 2,
+    _a-c_). The transverse rows of square pits indicate the
+    places of contact of these fibres and the cells of the
+    neighboring pith rays. Magnified about 25 times.]
+
+In pines and spruces the cells of the upper and lower rows of each
+tier or pith ray have "bordered" pits, like those of the wood fibre or
+tracheids proper, but the cells of the intermediate rows in the rays
+of cedars, etc., have only "simple" pits, _i.e._, pits devoid of the
+saucer-like "border" or rim. In pine, many of the pith rays are larger
+than the majority, each containing a whitish line, the horizontal
+resin duct, which, though much smaller, resembles the vertical ducts
+on the cross-section. The larger vertical resin ducts are best
+observed on removal of the bark from a fresh piece of white pine cut
+in the winter where they appear as conspicuous white lines, extending
+often for many inches up and down the stem. Neither the horizontal nor
+the vertical resin ducts are vessels or cells, but are openings
+between cells, _i.e._, intercellular spaces, in which the resin
+accumulates, freely oozing out when the ducts of a fresh piece of
+sapwood are cut. They are present only in our coniferous woods, and
+even here they are restricted to pine, spruce, and larch, and are
+normally absent in fir, cedar, cypress, and yew. Altogether, the
+structure of coniferous woods is very simple and regular, the bulk
+being made up of the small fibres called tracheids, the disturbing
+elements of pith rays and resin ducts being insignificant, and hence
+the great uniformity and great technical value of coniferous woods.
+
+
+
+
+                  LIST OF IMPORTANT CONIFEROUS WOODS
+
+
+                                 CEDAR
+
+Light soft, stiff, not strong, of fine texture. Sap- and heartwood
+distinct, the former lighter, the latter a dull grayish brown or red.
+The wood seasons rapidly, shrinks and checks but little, and is very
+durable in contact with the soil. Used like soft pine, but owing to
+its great durability preferred for shingles, etc. Cedars usually occur
+scattered, but they form in certain localities forests of considerable
+extent.
+
+
+                          (_a_) White Cedars
+
+=1. White Cedar= (_Thuya occidentalis_) (Arborvitæ, Tree of Life).
+Heartwood light yellowish brown, sapwood nearly white. Wood light,
+soft, not strong, of fine texture, very durable in contact with the
+soil, very fragrant. Scattered along streams and lakes, frequently
+covering extensive swamps; rarely large enough for lumber, but
+commonly used for fence posts, rails, railway ties, and shingles. This
+species has been extensively cultivated as an ornamental tree for at
+least a century. Maine to Minnesota and northward.
+
+=2. Canoe Cedar= (_Thuya gigantea_) (Red Cedar of the West). In Oregon
+and Washington a very large tree, covering extensive swamps; in the
+mountains much smaller, skirting the water courses. An important
+lumber tree. The wood takes a fine polish; suitable for interior
+finishing, as there is much variety of shading in the color.
+Washington to northern California and eastward to Montana.
+
+=3. White Cedar= (_Chamæcyparis thyoides_). Medium-sized tree. Heartwood
+light brown with rose tinge, sapwood paler. Wood light, soft, not
+strong, close-grained, easily worked, very durable in contact with the
+soil and very fragrant. Used in boatbuilding cooperage, interior
+finish, fence posts, railway ties, etc. Along the coast from Maine to
+Mississippi.
+
+=4. White Cedar= (_Chamæcyparis Lawsoniana_) (Port Orford Cedar, Oregon
+Cedar, Lawson's Cypress, Ginger Pine). A very large tree. A fine,
+close-grained, yellowish-white, durable timber, elastic, easily
+worked, free of knots, and fragrant. Extensively cut for lumber;
+heavier and stronger than any of the preceding. Along the coast line
+of Oregon.
+
+=5. White Cedar= (_Libocedrus decurrens_) (Incense Cedar). A large tree,
+abundantly scattered among pine and fir. Wood fine-grained. Cascades
+and Sierra Nevada Mountains of Oregon and California.
+
+=6. Yellow Cedar= (_Cupressus nootkatensis_) (Alaska Cedar, Alaska
+Cypress). A very large tree, much used for panelling and furniture. A
+fine, close-grained, yellowish white, durable timber, easily worked.
+Along the coast line of Oregon north.
+
+
+                           (_b_) Red Cedars
+
+=7. Red Cedar= (_Juniperus Virginiana_) (Savin Juniper, Juniper, Red
+Juniper, Juniper Bush, Pencil Cedar). Heartwood dull red color, thin
+sapwood nearly white. Close even grain, compact structure. Wood light,
+soft, weak, brittle, easily worked, durable in contact with the soil,
+and fragrant. Used for ties, posts, interior finish, pencil cases,
+cigar boxes, silos, tanks, and especially for lead pencils, for which
+purpose alone several million feet are cut each year. A small to
+medium-sized tree scattered through the forests, or in the West
+sparsely covering extensive areas (cedar brakes). The red cedar is the
+most widely distributed conifer of the United States, occurring from
+the Atlantic to the Pacific, and from Florida to Minnesota. Attains a
+suitable size for lumber only in the Southern, and more especially the
+Gulf States.
+
+=8. Red Cedar= (_Juniperus communis_) (Ground Cedar). Small-sized tree,
+its maximum height being about 25 feet. It is found widely distributed
+throughout the Northern hemisphere. Wood in its quality similar to the
+preceding. The fruit of this species is gathered in large quantities
+and used in the manufacture of gin; whose peculiar flavor and
+medicinal properties are due to the oil of Juniper berries, which is
+secured by adding the crushed fruit to undistilled grain spirit, or by
+allowing the vapor to pass over it before condensation. Used locally
+for construction purposes, fence posts, etc. Ranges from Greenland to
+Alaska, in the East, southward to Pennsylvania and northern Nebraska;
+in the Rocky Mountains to Texas, Mexico, and Arizona.
+
+=9. Redwood= (_Sequoia sempervirens_) (Sequoia, California Redwood,
+Coast Redwood). Wood in its quality and uses like white cedar. Thick,
+red heartwood, changing to reddish brown when seasoned. Thin sapwood,
+nearly white, coarse, straight grain, compact structure. Light, not
+strong, soft, very durable in contact with the soil, not resinous,
+easily worked, does not burn easily, receives high polish. Used for
+timber, shingles, flumes, fence posts, coffins, railway ties, water
+pipes, interior decorations, and cabinetmaking. A very large tree,
+limited to the coast ranges of California, and forming considerable
+forests, which are rapidly being converted into lumber.
+
+
+                                CYPRESS
+
+=10. Cypress= (_Taxodium distinchum_) (Bald Cypress, Black, White, and
+Red Cypress, Pecky Cypress). Wood in its appearance, quality, and uses
+similar to white cedar. "Black" and "White Cypress" are heavy and
+light forms of the same species. Heartwood brownish; sapwood nearly
+white. Wood close, straight-grain, frequently full of small holes
+caused by disease known as "pecky cypress." Greasy appearance and
+feeling. Wood light, soft, not strong, durable in contact with the
+soil, takes a fine polish. Green wood often very heavy. Used for
+carpentry, building construction, shingles, cooperage, railway ties,
+silos, tanks, vehicles, and washing machines. The cypress is a large,
+deciduous tree, inhabiting swampy lands, and along rivers and coasts
+of the Southern parts of the United States. Grows to a height of 150
+feet and 12 feet in diameter.
+
+
+                                  FIR
+
+This name is frequently applied to wood and to trees which are not
+fir; most commonly to spruce, but also, especially in English markets,
+to pine. It resembles spruce, but is easily distinguished from it, as
+well as from pine and larch, by the absence of resin ducts. Quality,
+uses, and habits similar to spruce.
+
+=11. Balsam Fir= (_Abies balsamea_) (Balsam, Fir Tree, Balm of Gilead
+Fir). Heartwood white to brownish; sapwood lighter color;
+coarse-grained, compact structure, satiny. Wood light, not durable or
+strong, resinous, easily split. Used for boxes, crates, doors,
+millwork, cheap lumber, paper pulp. Inferior to white pine or spruce,
+yet often mixed and sold with these species in the lumber market. A
+medium-sized tree scattered throughout the northern pineries, and cut
+in lumber operations whenever of sufficient size. Minnesota to Maine
+and northward.
+
+=12. White Fir= (_Abies grandis_ and _Abies concolor_). Medium-to very
+large-sized tree, forming an important part of most of the Western
+mountain forests, and furnishes much of the lumber of the respective
+regions. The former occurs from Vancouver to California, and the
+latter from Oregon to Arizona and eastward to Colorado and Mexico. The
+wood is soft and light, coarse-grained, not unlike the "Swiss pine" of
+Europe, but darker and firmer, and is not suitable for any purpose
+requiring strength. It is used for boxes, barrels, and to a small
+extent for wood pulp.
+
+=13. White Fir= (_Abies amabalis_). Good-sized tree, often forming
+extensive mountain forests. Wood similar in quality and uses to _Abies
+grandis_. Cascade Mountains of Washington and Oregon.
+
+=14. Red Fir= (_Abies nobilis_) (Noble Fir) (not to be confounded with
+Douglas spruce. See No. 40). Large to very large-sized tree, forming
+extensive forests on the slope of the mountains between 3,000 and
+4,000 feet elevation. Cascade Mountains of Oregon.
+
+=15. Red Fir= (_Abies magnifica_). Very large-sized tree, forming
+forests about the base of Mount Shasta. Sierra Nevada Mountains of
+California, from Mount Shasta southward.
+
+
+                                HEMLOCK
+
+Light to medium weight, soft, stiff, but brittle, commonly
+cross-grained, rough and splintery. Sapwood and heartwood not well
+defined. The wood of a light reddish-gray color, free from resin
+ducts, moderately durable, shrinks and warps considerably in drying,
+wears rough, retains nails firmly. Used principally for dimension
+stuff and timbers. Hemlocks are medium- to large-sized trees, commonly
+scattered among broad-leaved trees and conifers, but often forming
+forests of almost pure growth.
+
+=16. Hemlock= (_Tsuga canadensis_) (Hemlock Spruce, Peruche).
+Medium-sized tree, furnishes almost all the hemlock of the Eastern
+market. Maine to Wisconsin, also following the Alleghanies southward
+to Georgia and Alabama.
+
+=17. Hemlock= (_Tsuga mertensiana_). Large-sized tree, wood claimed to
+be heavier and harder than the Eastern species and of superior
+quality. Used for pulp wood, floors, panels, and newels. It is not
+suitable for heavy construction, especially where exposed to the
+weather, it is straight in grain and will take a good polish. Not
+adapted for use partly in and partly out of the ground; in fresh water
+as piles will last about ten years, but as it is softer than fir it is
+less able to stand driving successfully. Washington to California and
+eastward to Montana.
+
+
+                           LARCH or TAMARACK
+
+Wood like the best of hard pine both in appearance, quality, and uses,
+and owing to its great durability somewhat preferred in shipbuilding,
+for telegraph poles, and railway ties. In its structure it resembles
+spruce. The larches are deciduous trees, occasionally covering
+considerable areas, but usually scattered among other conifers.
+
+=18. Tamarack= (_Larix laricina_ var. _Americana_) (Larch, Black Larch,
+American Larch, Hacmatac). Heartwood light brown in color, sapwood
+nearly white, coarse conspicuous grain, compact structure, annual
+rings pronounced. Wood heavy, hard, very strong, durable in contact
+with the soil. Used for railway ties, fence posts, sills, ship
+timbers, telegraph poles, flagstaffs. Medium-sized tree, often
+covering swamps, in which case it is smaller and of poor quality.
+Maine to Minnesota, and southward to Pennsylvania.
+
+=19. Tamarack= (_Larix occidentalis_) (Western Larch, Larch).
+Large-sized trees, scattered, locally abundant. Is little inferior to
+oak in strength and durability. Heartwood of a light brown color with
+lighter sapwood, has a fine, slightly satiny grain, and is fairly free
+from knots; the annual rings are distant. Used for railway ties and
+shipbuilding. Washington and Oregon to Montana.
+
+
+                                 PINE
+
+Very variable, very light and soft in "soft" pine, such as white pine;
+of medium weight to heavy and quite hard in "hard" pine, of which the
+long-leaf or Georgia pine is the extreme form. Usually it is stiff,
+quite strong, of even texture, and more or less resinous. The sapwood
+is yellowish white; the heartwood orange brown. Pine shrinks
+moderately, seasons rapidly and without much injury; it works easily,
+is never too hard to nail (unlike oak or hickory); it is mostly quite
+durable when in contact with the soil, and if well seasoned is not
+subject to the attacks of boring insects. The heavier the wood, the
+darker, stronger, and harder it is, and the more it shrinks and checks
+when seasoning. Pine is used more extensively than any other wood. It
+is the principal wood in carpentry, as well as in all heavy
+construction, bridges, trestles, etc. It is also used in almost every
+other wood industry; for spars, masts, planks, and timbers in
+shipbuilding, in car and wagon construction, in cooperage and
+woodenware; for crates and boxes, in furniture work, for toys and
+patterns, water pipes, excelsior, etc. Pines are usually large-sized
+trees with few branches, the straight, cylindrical, useful stem
+forming by far the greatest part of the tree. They occur gregariously,
+forming vast forests, a fact which greatly facilitates their
+exploitation. Of the many special terms applied to pine as lumber,
+denoting sometimes differences in quality, the following deserve
+attention: "White pine," "pumpkin pine," "soft pine," in the Eastern
+markets refer to the wood of the white pine (_Pinus strobus_), and on
+the Pacific Coast to that of the sugar pine (_Pinus lambertiana_).
+"Yellow pine" is applied in the trade to all the Southern lumber
+pines; in the Northwest it is also applied to the pitch pine (_Pinus
+regida_); in the West it refers mostly to the bull pine (_Pinus
+ponderosa_). "Yellow long-leaf pine" (Georgia pine), chiefly used in
+advertisements, refers to the long-leaf Pine (_Pinus palustris_).
+
+
+                           (_a_) Soft Pines
+
+=20. White Pine= (_Pinus strobus_) (Soft Pine, Pumpkin Pine, Weymouth
+Pine, Yellow Deal). Large to very large-sized tree, reaching a height
+of 80 to 100 feet or more, and in some instances 7 or 8 feet in
+diameter. For the last fifty years the most important timber tree of
+the United States, furnishing the best quality of soft pine. Heartwood
+cream white; sapwood nearly white. Close straight grain, compact
+structure; comparatively free from knots and resin. Soft, uniform;
+seasons well; easy to work; nails without splitting; fairly durable in
+contact with the soil; and shrinks less than other species of pine.
+Paints well. Used for carpentry, construction, building, spars, masts,
+matches, boxes, etc., etc., etc.
+
+=21. Sugar Pine= (_Pinus lambertiana_) (White Pine, Pumpkin Pine, Soft
+Pine). A very large tree, forming extensive forests in the Rocky
+Mountains and furnishing most of the timber of the western United
+States. It is confined to Oregon and California, and grows at from
+1,500 to 8,000 feet above sea level. Has an average height of 150 to
+175 feet and a diameter of 4 to 5 feet, with a maximum height of 235
+feet and 12 feet in diameter. The wood is soft, durable,
+straight-grained, easily worked, very resinous, and has a satiny
+luster which makes it appreciated for interior work. It is extensively
+used for doors, blinds, sashes, and interior finish, also for
+druggists' drawers, owing to its freedom from odor, for oars,
+mouldings, shipbuilding, cooperage, shingles, and fruit boxes. Oregon
+and California.
+
+=22. White Pine= (_Pinus monticolo_). A large tree, at home in Montana,
+Idaho, and the Pacific States. Most common and locally used in
+northern Idaho.
+
+=23. White Pine= (_Pinus flexilis_). A small-sized tree, forming
+mountain forests of considerable extent and locally used. Eastern
+Rocky Mountain slopes, Montana to New Mexico.
+
+
+                           (_b_) Hard Pines
+
+=24. Long-Leaf Pine= (_Pinus palustris_) (Georgia Pine, Southern Pine,
+Yellow Pine, Southern Hard Pine, Long-straw Pine, etc.). Large-sized
+tree. This species furnishes the hardest and most durable as well as
+one of the strongest pine timbers in the market. Heartwood orange,
+sapwood lighter color, the annual rings are strongly marked, and it is
+full of resinous matter, making it very durable, but difficult to
+work. It is hard, dense, and strong, fairly free from knots,
+straight-grained, and one of the best timbers for heavy engineering
+work where great strength, long span, and durability are required.
+Used for heavy construction, shipbuilding, cars, docks, beams, ties,
+flooring, and interior decoration. Coast region from North Carolina to
+Texas.
+
+=25. Bull Pine= (_Pinus ponderosa_) (Yellow Pine, Western Yellow Pine,
+Western Pine, Western White Pine, California White Pine). Medium- to
+very large-sized tree, forming extensive forests in the Pacific and
+Rocky Mountain regions. Heartwood reddish brown, sapwood yellowish
+white, and there is often a good deal of it. The resinous smell of the
+wood is very remarkable. It is extensively used for beams, flooring,
+ceilings, and building work generally.
+
+=26. Bull Pine= (_Pinus Jeffreyi_) (Black Pine). Large-sized tree, wood
+resembles _Pinus ponderosa_ and replacing same at high altitudes. Used
+locally in California.
+
+=27. Loblolly Pine= (_Pinus tæda_) (Slash Pine, Old Field Pine, Rosemary
+Pine, Sap Pine, Short-straw Pine). A large-sized tree, forms extensive
+forests. Wider-ringed, coarser, lighter, softer, with more sapwood
+than the long-leaf pine, but the two are often confounded in the
+market. The more Northern tree produces lumber which is weak, brittle,
+coarse-grained, and not durable, the Southern tree produces a better
+quality wood. Both are very resinous. This is the common lumber pine
+from Virginia to South Carolina, and is found extensively in Arkansas
+and Texas. Southern States, Virginia to Texas and Arkansas.
+
+=28. Norway Pine= (_Pinus resinosa_) (American Red Pine, Canadian Pine).
+Large-sized tree, never forming forests, usually scattered or in
+small groves, together with white pine. Largely sapwood and hence not
+durable. Heartwood reddish white, with fine, clear grain, fairly tough
+and elastic, not liable to warp and split. Used for building
+construction, bridges, piles, masts, and spars. Minnesota to Michigan;
+also in New England to Pennsylvania.
+
+=29. Short-Leaf Pine= (_Pinus echinata_) (Slash Pine, Spruce Pine,
+Carolina Pine, Yellow Pine, Old Field Pine, Hard Pine). A medium- to
+large-sized tree, resembling loblolly pine, often approaches in its
+wood the Norway pine. Heartwood orange, sapwood lighter; compact
+structure, apt to be variable in appearance in cross-section. Wood
+usually hard, tough, strong, durable, resinous. A valuable timber
+tree, sometimes worked for turpentine. Used for heavy construction,
+shipbuilding, cars, docks, beams, ties, flooring, and house trim.
+_Pinus echinata_, _palustris_, and _tæda_ are very similar in
+character, of thin wood and very difficult to distinguish one from
+another. As a rule, however, _palustris_ (Long-leaf Pine) has the
+smallest and most uniform growth rings, and _Pinus tæda_ (Loblolly
+Pine) has the largest. All are apt to be bunched together in the
+lumber market as Southern Hard Pine. All are used for the same
+purposes. Short-leaf is the common lumber pine of Missouri and
+Arkansas. North Carolina to Texas and Missouri.
+
+=30. Cuban Pine= (_Pinus cubensis_) (Slash Pine, Swamp Pine, Bastard
+Pine, Meadow Pine). Resembles long-leaf pine, but commonly has a wider
+sapwood and coarser grain. Does not enter the markets to any extent.
+Along the coast from South Carolina to Louisiana.
+
+=31. Pitch Pine= (_Pinus rigida_) (Torch Pine). A small to medium-sized
+tree. Heartwood light brown or red, sapwood yellowish white. Wood
+light, soft, not strong, coarse-grained, durable, very resinous. Used
+locally for lumber, fuel, and charcoal. Coast regions from New York
+to Georgia, and along the mountains to Kentucky.
+
+=32. Black Pine= (_Pinus murryana_) (Lodge-pole Pine, Tamarack).
+Small-sized tree. Rocky Mountains and Pacific regions.
+
+=33. Jersey Pine= (_Pinus inops_ var. _Virginiana_) (Scrub Pine).
+Small-sized tree. Along the coast from New York to Georgia and along
+the mountains to Kentucky.
+
+=34. Gray Pine= (_Pinus divaricata_ var. _banksiana_) (Scrub Pine, Jack
+Pine). Medium- to large-sized tree. Heartwood pale brown, rarely
+yellow; sapwood nearly white. Wood light, soft, not strong,
+close-grained. Used for fuel, railway ties, and fence posts. In days
+gone by the Indians preferred this species for frames of canoes.
+Maine, Vermont, and Michigan to Minnesota.
+
+
+                          REDWOOD (See Cedar)
+
+                                SPRUCE
+
+Resembles soft pine, is light, very soft, stiff, moderately strong,
+less resinous than pine; has no distinct heartwood, and is of whitish
+color. Used like soft pine, but also employed as resonance wood in
+musical instruments and preferred for paper pulp. Spruces, like pines,
+form extensive forests. They are more frugal, thrive on thinner soils,
+and bear more shade, but usually require a more humid climate. "Black"
+and "White" spruce as applied by lumbermen usually refer to narrow and
+wide-ringed forms of black spruce (_Picea nigra_).
+
+=35. Black Spruce= (_Picea nigra_ var. _mariana_). Medium-sized tree,
+forms extensive forests in northwestern United States and in British
+America; occurs scattered or in groves, especially in low lands
+throughout the northern pineries. Important lumber tree in eastern
+United States. Heartwood pale, often with reddish tinge; sapwood pure
+white. Wood light, soft, not strong. Chiefly used for manufacture of
+paper pulp, and great quantities of this as well as _Picea alba_ are
+used for this purpose. Used also for sounding boards for pianos,
+violins, etc. Maine to Minnesota, British America, and in the
+Alleghanies to North Carolina.
+
+=36. White Spruce= (_Picea canadensis_ var. _alba_). Medium- to
+large-sized tree. Heartwood light yellow; sapwood nearly white.
+Generally associated with the preceding. Most abundant along streams
+and lakes, grows largest in Montana and forms the most important tree
+of the sub-arctic forest of British America. Used largely for floors,
+joists, doors, sashes, mouldings, and panel work, rapidly superceding
+_Pinus strobus_ for building purposes. It is very similar to Norway
+pine, excels it in toughness, is rather less durable and dense, and
+more liable to warp in seasoning. Northern United States from Maine to
+Minnesota, also from Montana to Pacific, British America.
+
+=37. White Spruce= (_Picea engelmanni_). Medium- to large-sized tree,
+forming extensive forests at elevations from 5,000 to 10,000 feet
+above sea level; resembles the preceding, but occupies a different
+station. A very important timber tree in the central and southern
+parts of the Rocky Mountains. Rocky Mountains from Mexico to Montana.
+
+=38. Tide-Land Spruce= (_Picea sitchensis_) (Sitka Spruce). A
+large-sized tree, forming an extensive coast-belt forest. Used
+extensively for all classes of cooperage and woodenware on the Pacific
+Coast. Along the sea-coast from Alaska to central California.
+
+=39. Red Spruce= (_Picea rubens_). Medium-sized tree, generally
+associated with _Picea nigra_ and occurs scattered throughout the
+northern pineries. Heartwood reddish; sapwood lighter color,
+straight-grained, compact structure. Wood light, soft, not strong,
+elastic, resonant, not durable when exposed. Used for flooring,
+carpentry, shipbuilding, piles, posts, railway ties, paddles, oars,
+sounding boards, paper pulp, and musical instruments. Montana to
+Pacific, British America.
+
+
+                            BASTARD SPRUCE
+
+Spruce or fir in name, but resembling hard pine or larch in
+appearance, quality and uses of its wood.
+
+=40. Douglas Spruce= (_Pseudotsuga douglasii_) (Yellow Fir, Red Fir,
+Oregon Pine). One of the most important trees of the western United
+States; grows very large in the Pacific States, to fair size in all
+parts of the mountains, in Colorado up to about 10,000 feet above sea
+level; forms extensive forests, often of pure growth, it is really
+neither a pine nor a fir. Wood very variable, usually coarse-grained
+and heavy, with very pronounced summer-wood. Hard and strong ("red"
+fir), but often fine-grained and light ("yellow" fir). It is the chief
+tree of Washington and Oregon, and most abundant and most valuable in
+British Columbia, where it attains its greatest size. From the plains
+to the Pacific Ocean, and from Mexico to British Columbia.
+
+=41. Red Fir= (_Pseudotsuga taxifolia_) (Oregon Pine, Puget Sound Pine,
+Yellow Fir, Douglas Spruce, Red Pine). Heartwood light red or yellow
+in color, sapwood narrow, nearly white, comparatively free from
+resins, variable annual rings. Wood usually hard, strong, difficult to
+work, durable, splinters easily. Used for heavy construction,
+dimension timber, railway ties, doors, blinds, interior finish, piles,
+etc. One of the most important of Western trees. From the plains to
+the Pacific Ocean, and from Mexico to British America.
+
+
+                         TAMARACK (See Larch)
+
+
+                                  YEW
+
+Wood heavy, hard, extremely stiff and strong, of fine texture with a
+pale yellow sapwood, and an orange-red heartwood; seasons well and is
+quite durable. Extensively used for archery bows, turner's ware, etc.
+The yews form no forests, but occur scattered with other conifers.
+
+=42. Yew= (_Taxus brevifolia_). A small to medium-sized tree of the
+Pacific region.
+
+
+
+
+                              SECTION III
+
+                          BROAD-LEAVED TREES
+
+                      WOOD OF BROAD-LEAVED TREES
+
+
+    [Illustration: Fig. 4. Block of Oak. CS, cross-section; RS,
+    radial section; TS, tangential section; _mr_, medullary or
+    pith ray; _a_, height; _b_, width; and _e_, length of pith
+    ray.]
+
+    [Illustration: Fig. 5. Board of Oak. CS, cross-section; RS,
+    radial section; TS, tangential section; _v_, vessels or
+    pores, cut through.; A, slight curve in log which appears in
+    section as an islet.]
+
+    [Illustration: Fig. 6. Cross-section of Oak (Magnified about
+    5 times).]
+
+On a cross-section of oak, the same arrangement of pith and bark, of
+sapwood and heartwood, and the same disposition of the wood in
+well-defined concentric or annual rings occur, but the rings are
+marked by lines or rows of conspicuous pores or openings, which occupy
+the greater part of the spring-wood for each ring (see Fig. 4, also
+6), and are, in fact the hollows of vessels through which the cut has
+been made. On the radial section or quarter-sawn board the several
+layers appear as so many stripes (see Fig. 5); on the tangential
+section or "bastard" face patterns similar to those mentioned for pine
+wood are observed. But while the patterns in hard pine are marked by
+the darker summer-wood, and are composed of plain, alternating stripes
+of darker and lighter wood, the figures in oak (and other broad-leaved
+woods) are due chiefly to the vessels, those of the spring-wood in oak
+being the most conspicuous (see Fig. 5). So that in an oak table, the
+darker, shaded parts are the spring-wood, the lighter unicolored parts
+the summer-wood. On closer examination of the smooth cross-section of
+oak, the spring-wood part of the ring is found to be formed in great
+part of pores; large, round, or oval openings made by the cut through
+long vessels. These are separated by a grayish and quite porous
+tissue (see Fig. 6, A), which continues here and there in the form of
+radial, often branched, patches (not the pith rays) into and through
+the summer-wood to the spring-wood of the next ring. The large vessels
+of the spring-wood, occupying six to ten per cent of the volume of a
+log in very good oak, and twenty-five per cent or more in inferior and
+narrow-ringed timber, are a very important feature, since it is
+evident that the greater their share in the volume, the lighter and
+weaker the wood. They are smallest near the pith, and grow wider
+outward. They are wider in the stem than limb, and seem to be of
+indefinite length, forming open channels, in some cases probably as
+long as the tree itself. Scattered through the radiating gray patches
+of porous wood are vessels similar to those of the spring-wood, but
+decidedly smaller. These vessels are usually fewer and larger near the
+outer portions of the ring. Their number and size can be utilized to
+distinguish the oaks classed as white oaks from those classed as black
+and red oaks. They are fewer and larger in red oaks, smaller but much
+more numerous in white oaks. The summer-wood, except for these radial,
+grayish patches, is dark colored and firm. This firm portion, divided
+into bodies or strands by these patches of porous wood, and also by
+fine, wavy, concentric lines of short, thin-walled cells (see Fig. 6,
+A), consists of thin-walled fibres (see Fig. 7, B), and is the chief
+element of strength in oak wood. In good white oak it forms one-half
+or more of the wood, if it cuts like horn, and the cut surface is
+shiny, and of a deep chocolate brown color. In very narrow-ringed wood
+and in inferior red oak it is usually much reduced in quantity as well
+as quality. The pith rays of the oak, unlike those of the coniferous
+woods, are at least in part very large and conspicuous. (See Fig. 4;
+their height indicated by the letter _a_, and their width by the
+letter _b_.) The large medullary rays of oak are often twenty and more
+cells wide, and several hundred cell rows in height, which amount
+commonly to one or more inches. These large rays are conspicuous on
+all sections. They appear as long, sharp, grayish lines on the
+cross-sections; as short, thick lines, tapering at each end, on the
+tangential or "bastard" face, and as broad, shiny bands, "the
+mirrors," on the radial section. In addition to these coarse rays,
+there is also a large number of small pith rays, which can be seen
+only when magnified. On the whole, the pith rays form a much larger
+part of the wood than might be supposed. In specimens of good white
+oak it has been found that they form about sixteen to twenty-five per
+cent of the wood.
+
+    [Illustration: Fig. 7. Portion of the Firm Bodies of Fibres
+    with Two Cells of a Small Pith Ray _mr_ (Highly Magnified).]
+
+    [Illustration: Fig. 8. Isolated Fibres and Cells, _a_, four
+    cells of wood, parenchyma; _b_, two cells from a pith ray;
+    _c_, a single joint or cell of a vessel, the openings _x_
+    leading into its upper and lower neighbors; _d_, tracheid;
+    _e_, wood fibre proper.]
+
+
+                           Minute Structure
+
+    [Illustration: Fig. 9. Cross-section of Basswood (Magnified).
+    _v_, vessels; _mr_, pith rays.]
+
+If a well-smoothed thin disk or cross-section of oak (say
+one-sixteenth inch thick) is held up to the light, it looks very much
+like a sieve, the pores or vessels appearing as clean-cut holes. The
+spring-wood and gray patches are seen to be quite porous, but the firm
+bodies of fibres between them are dense and opaque. Examined with a
+magnifier it will be noticed that there is no such regularity of
+arrangement in straight rows as is conspicuous in pine. On the
+contrary, great irregularity prevails. At the same time, while the
+pores are as large as pin holes, the cells of the denser wood, unlike
+those of pine wood, are too small to be distinguished. Studied with
+the microscope, each vessel is found to be a vertical row of a great
+number of short, wide tubes, joined end to end (see Fig. 8, _c_). The
+porous spring-wood and radial gray tracts are partly composed of
+smaller vessels, but chiefly of tracheids, like those of pine, and of
+shorter cells, the "wood parenchyma," resembling the cells of the
+medullary rays. These latter, as well as the fine concentric lines
+mentioned as occurring in the summer-wood, are composed entirely of
+short tube-like parenchyma cells, with square or oblique ends (see
+Fig. 8, _a_ and _b_). The wood fibres proper, which form the dark,
+firm bodies referred to, are very fine, thread-like cells, one
+twenty-fifth to one-tenth inch long, with a wall commonly so thick
+that scarcely any empty internal space or lumen remains (see Figs. 8,
+_e_, and 7, B). If, instead of oak, a piece of poplar or basswood (see
+Fig. 9) had been used in this study, the structure would have been
+found to be quite different. The same kinds of cell-elements, vessels,
+etc., are, to be sure, present, but their combination and arrangement
+are different, and thus from the great variety of possible
+combinations results the great variety of structure and, in
+consequence, of the qualities which distinguish the wood of
+broad-leaved trees. The sharp distinction of sap wood and heartwood is
+wanting; the rings are not so clearly defined; the vessels of the
+wood are small, very numerous, and rather evenly scattered through the
+wood of the annual rings, so that the distinction of the ring almost
+vanishes and the medullary or pith rays in poplar can be seen, without
+being magnified, only on the radial section.
+
+
+         LIST OF MOST IMPORTANT BROAD-LEAVED TREES (HARDWOODS)
+
+Woods of complex and very variable structure, and therefore differing
+widely in quality, behavior, and consequently in applicability to the
+arts.
+
+
+                               AILANTHUS
+
+=1. Ailanthus= (_Ailanthus glandulosa_). Medium to large-sized tree.
+Wood pale yellow, hard, fine-grained, and satiny. This species
+originally came from China, where it is known as the Tree of "Heaven,"
+was introduced into the United States and planted near Philadelphia
+during the 18th century, and is more ornamental than useful. It is
+used to some extent in cabinet work. Western Pennsylvania and Long
+Island, New York.
+
+
+                                  ASH
+
+Wood heavy, hard, stiff, quite tough, not durable in contact with the
+soil, straight-grained, rough on the split surfaces and coarse in
+texture. The wood shrinks moderately, seasons with little injury,
+stands well, and takes a good polish. In carpentry, ash is used for
+stairways, panels, etc. It is used in shipbuilding, in the
+construction of cars, wagons, etc., in the manufacture of all kinds of
+farm implements, machinery, and especially of all kinds of furniture;
+for cooperage, baskets, oars, tool handles, hoops, etc., etc. The
+trees of the several species of ash are rapid growers, of small to
+medium height with stout trunks. They form no forests, but occur
+scattered in almost all our broad-leaved forests.
+
+=2. White Ash= (_Fraxinus Americana_). Medium-, sometimes large-sized
+tree. Heartwood reddish brown, usually mottled; sapwood lighter color,
+nearly white. Wood heavy, hard, tough, elastic, coarse-grained,
+compact structure. Annual rings clearly marked by large open pores,
+not durable in contact with the soil, is straight-grained, and the
+best material for oars, etc. Used for agricultural implements, tool
+handles, automobile (rim boards), vehicle bodies and parts, baseball
+bats, interior finish, cabinet work, etc., etc. Basin of the Ohio, but
+found from Maine to Minnesota and Texas.
+
+=3. Red Ash= (_Fraxinus pubescens_ var. _Pennsylvanica_). Medium-sized
+tree, a timber very similar to, but smaller than _Fraxinus Americana_.
+Heartwood light brown, sapwood lighter color. Wood heavy, hard,
+strong, and coarse-grained. Ranges from New Brunswick to Florida, and
+westward to Dakota, Nebraska, and Kansas.
+
+=4. Black Ash= (_Fraxinus nigra_ var. _sambucifolia_) (Hoop Ash, Ground
+Ash). Medium-sized tree, very common, is more widely distributed than
+the _Fraxinus Americana_; the wood is not so hard, but is well suited
+for hoops and basketwork. Heartwood dark brown, sapwood light brown or
+white. Wood heavy, rather soft, tough and coarse-grained. Used for
+barrel hoops, basketwork, cabinetwork and interior of houses. Maine to
+Minnesota and southward to Alabama.
+
+=5. Blue Ash= (_Fraxinus quadrangulata_). Small to medium-sized tree.
+Heartwood yellow, streaked with brown, sapwood a lighter color. Wood
+heavy, hard, and coarse-grained. Not common. Indiana and Illinois;
+occurs from Michigan to Minnesota and southward to Alabama.
+
+=6. Green Ash= (_Fraxinus viridis_). Small-sized tree. Occurs from New
+York to the Rocky Mountains, and southward to Florida and Arizona.
+
+=7. Oregon Ash= (_Fraxinus Oregana_). Small to medium-sized tree. Occurs
+from western Washington to California.
+
+=8. Carolina Ash= (_Fraxinus Caroliniana_). Medium-sized tree. Occurs in
+the Carolinas and the coast regions southward.
+
+
+                          ASPEN (See Poplar)
+
+
+                               BASSWOOD
+
+=9. Basswood= (_Tilia Americana_) (Linden, Lime Tree, American Linden,
+Lin, Bee Tree). Medium- to large-sized tree. Wood light, soft, stiff,
+but not strong, of fine texture, straight and close-grained, and white
+to light brown color, but not durable in contact with the soil. The
+wood shrinks considerably in drying, works well and stands well in
+interior work. It is used for cooperage, in carpentry, in the
+manufacture of furniture and woodenware (both turned and carved), for
+toys, also for panelling of car and carriage bodies, for agricultural
+implements, automobiles, sides and backs of drawers, cigar boxes,
+excelsior, refrigerators, trunks, and paper pulp. It is also largely
+cut for veneer and used as "three-ply" for boxes and chair seats. It
+is used for sounding boards in pianos and organs. If well seasoned and
+painted it stands fairly well for outside work. Common in all northern
+broad-leaved forests. Found throughout the eastern United States, but
+reaches its greatest size in the Valley of the Ohio, becoming often
+130 feet in height, but its usual height is about 70 feet.
+
+=10. White Basswood= (_Tilia heterophylla_) (Whitewood). A small-sized
+tree. Wood in its quality and uses similar to the preceding, only it
+is lighter in color. Most abundant in the Alleghany region.
+
+=11. White Basswood= (_Tilia pubescens_) (Downy Linden, Small-leaved
+Basswood). Small-sized tree. Wood in its quality and uses similar to
+_Tilia Americana_. This is a Southern species which makes it way as
+far north as Long Island. Is found at its best in South Carolina.
+
+
+                                 BEECH
+
+=12. Beech= (_Fagus ferruginea_) (Red Beech, White Beech). Medium-sized
+tree, common, sometimes forming forests of pure growth. Wood heavy,
+hard, stiff, strong, of rather coarse texture, white to light brown
+color, not durable in contact with the soil, and subject to the
+inroads of boring insects. Rather close-grained, conspicuous medullary
+rays, and when quarter-sawn and well smoothed is very beautiful. The
+wood shrinks and checks considerably in drying, works well and stands
+well, and takes a fine polish. Beech is comparatively free from
+objectionable taste, and finds a place in the manufacture of
+commodities which come in contact with foodstuffs, such as lard tubs,
+butter boxes and pails, and the beaters of ice cream freezers; for the
+latter the persistent hardness of the wood when subjected to attrition
+and abrasion, while wet gives it peculiar fitness. It is an excellent
+material for churns. Sugar hogsheads are made of beech, partly because
+it is a tasteless wood and partly because it has great strength. A
+large class of woodenware, including veneer plates, dishes, boxes,
+paddles, scoops, spoons, and beaters, which belong to the kitchen and
+pantry, are made of this species of wood. Beech picnic plates are made
+by the million, a single machine turning out 75,000 a day. The wood
+has a long list of miscellaneous uses and enters in a great variety of
+commodities. In every region where it grows in commercial quantities
+it is made into boxes, baskets, and crating. Beech baskets are chiefly
+employed in shipping fruit, berries, and vegetables. In Maine thin
+veneer of beech is made specially for the Sicily orange and lemon
+trade. This is shipped in bulk and the boxes are made abroad. Beech is
+also an important handle wood, although not in the same class with
+hickory. It is not selected because of toughness and resiliency, as
+hickory is, and generally goes into plane, handsaw, pail, chisel, and
+flatiron handles. Recent statistics show that in the production of
+slack cooperage staves, only two woods, red gum and pine, stood above
+beech in quantity, while for heading, pine alone exceeded it. It is
+also used in turnery, for shoe lasts, butcher blocks, ladder rounds,
+etc. Abroad it is very extensively used by the carpenter, millwright,
+and wagon maker, in turnery and wood carving. Most abundant in the
+Ohio and Mississippi basin, but found from Maine to Wisconsin and
+southward to Florida.
+
+
+                                 BIRCH
+
+=13. Cherry Birch= (_Betula lenta_) (Black Birch, Sweet Birch, Mahogany
+Birch, Wintergreen Birch). Medium-sized tree, very common. Wood of
+beautiful reddish or yellowish brown, and much of it nicely figured,
+of compact structure, is straight in grain, heavy, hard, strong, takes
+a fine polish, and considerably used as imitation of mahogany. The
+wood shrinks considerably in drying, works well and stands well, but
+is not durable in contact with the soil. The medullary rays in birch
+are very fine and close and not easily seen. The sweet birch is very
+handsome, with satiny luster, equalling cherry, and is too costly a
+wood to be profitably used for ordinary purposes, but there are both
+high and low grades of birch, the latter consisting chiefly of sapwood
+and pieces too knotty for first class commodities. This cheap material
+swells the supply of box lumber, and a little of it is found wherever
+birch passes through sawmills. The frequent objections against sweet
+birch as box lumber and crating material are that it is hard to nail
+and is inclined to split. It is also used for veneer picnic plates and
+butter dishes, although it is not as popular for this class of
+commodity as are yellow and paper birch, maple and beech. The best
+grades are largely used for furniture and cabinet work, and also for
+interior finish. Maine to Michigan and to Tennessee.
+
+=14. White Birch= (_Betula populifolia_) (Gray Birch, Old Field Birch,
+Aspen-leaved Birch). Small to medium-sized tree, least common of all
+the birches. Short-lived, twenty to thirty feet high, grows very
+rapidly. Heartwood light brown, sapwood lighter color. Wood light,
+soft, close-grained, not strong, checks badly in drying, decays
+quickly, not durable in contact with the soil, takes a good polish.
+Used for spools, shoepegs, wood pulp, and barrel hoops. Fuel, value
+not high, but burns with bright flame. Ranges from Nova Scotia and
+lower St. Lawrence River, southward, mostly in the coast region to
+Delaware, and westward through northern New England and New York to
+southern shore of Lake Ontario.
+
+=15. Yellow Birch= (_Betula lutea_) (Gray Birch, Silver Birch). Medium-
+to large-sized tree, very common. Heartwood light reddish brown,
+sapwood nearly white, close-grained, compact structure, with a satiny
+luster. Wood heavy, very strong, hard, tough, susceptible of high
+polish, not durable when exposed. Is similar to _Betula lenta_, and
+finds a place in practically all kinds of woodenware. A large
+percentage of broom handles on the market are made of this species of
+wood, though nearly every other birch contributes something. It is
+used for veneer plates and dishes made for pies, butter, lard, and
+many other commodities. Tubs and pails are sometimes made of yellow
+birch provided weight is not objectionable. The wood is twice as heavy
+as some of the pines and cedars. Many small handles for such articles
+as flatirons, gimlets, augers, screw drivers, chisels, varnish and
+paint brushes, butcher and carving knives, etc. It is also widely used
+for shipping boxes, baskets, and crates, and it is one of the
+stiffest, strongest woods procurable, but on account of its excessive
+weight it is sometimes discriminated against. It is excellent for
+veneer boxes, and that is probably one of the most important places it
+fills. Citrus fruit from northern Africa and the islands and countries
+of the Mediterranean is often shipped to market in boxes made of
+yellow birch from veneer cut in New England. The better grades are
+also used for furniture and cabinet work, and the "burls" found on
+this species are highly valued for making fancy articles, gavels, etc.
+It is extensively used for turnery, buttons, spools, bobbins, wheel
+hubs, etc. Maine to Minnesota and southward to Tennessee.
+
+=16. Red Birch= (_Betula rubra_ var. _nigra_) (River Birch). Small to
+medium-sized tree, very common. Lighter and less valuable than the
+preceding. Heartwood light brown, sapwood pale. Wood light, fairly
+strong and close-grained. Red birch is best developed in the middle
+South, and usually grows near the banks of rivers. Its bark hangs in
+tatters, even worse than that of paper birch, but it is darker. In
+Tennessee the slack coopers have found that red birch makes excellent
+barrel heads and it is sometimes employed in preference to other
+woods. In eastern Maryland the manufacturers of peach baskets draw
+their supplies from this wood, and substitute it for white elm in
+making the hoops or bands which stiffen the top of the basket, and
+provide a fastening for the veneer which forms the sides. Red birch
+bends in a very satisfactory manner, which is an important point. This
+wood enters pretty generally into the manufacture of woodenware within
+its range, but statistics do not mention it by name. It is also used
+in the manufacture of veneer picnic plates, pie plates, butter dishes,
+washboards, small handles, kitchen and pantry utensils, and ironing
+boards. New England to Texas and Missouri.
+
+=17. Canoe Birch= (_Betula paprifera_) (White Birch, Paper Birch). Small
+to medium-sized tree, sometimes forming forests, very common.
+Heartwood light brown tinged with red, sapwood lighter color. Wood of
+good quality, but light, fairly hard and strong, tough, close-grained.
+Sap flows freely in spring and by boiling can be made into syrup. Not
+as valuable as any of the preceding. Canoe birch is a northern tree,
+easily identified by its white trunk and its ragged bark. Large
+numbers of small wooden boxes are made by boring out blocks of this
+wood, shaping them in lathes, and fitting lids on them. Canoe birch is
+one of the best woods for this class of commodities, because it can be
+worked very thin, does not split readily, and is of pleasing color.
+Such boxes, or two-piece diminutive kegs, are used as containers for
+articles shipped and sold in small bulk, such as tacks, small nails,
+and brads. Such containers are generally cylindrical and of
+considerably greater depth than diameter. Many others of nearly
+similar form are made to contain ink bottles, bottles of perfumery,
+drugs, liquids, salves, lotions, and powders of many kinds. Many boxes
+of this pattern are used by manufacturers of pencils and crayons for
+packing and shipping their wares. Such boxes are made in numerous
+numbers by automatic machinery. A single machine of the most improved
+pattern will turn out 1,400 boxes an hour. After the boring and
+turning are done, they are smoothed by placing them into a tumbling
+barrel with soapstone. It is also used for one-piece shallow trays or
+boxes, without lids, and used as card receivers, pin receptacles,
+butter boxes, fruit platters, and contribution plates in churches. It
+is also the principal wood used for spools, bobbins, bowls, shoe
+lasts, pegs, and turnery, and is also much used in the furniture
+trade. All along the northern boundary of the United States and
+northward, from the Atlantic to the Pacific.
+
+
+                       BLACK WALNUT (See Walnut)
+
+
+                              BLUE BEECH
+
+=18. Blue Beech= (_Carpinus Caroliniana_) (Hornbeam, Water Beech,
+Ironwood). Small-sized tree. Heartwood light brown, sapwood nearly
+white. Wood very hard, heavy, strong, very stiff, of rather fine
+texture, not durable in contact with the soil, shrinks and checks
+considerably in drying, but works well and stands well, and takes a
+fine polish. Used chiefly in turnery, for tool handles, etc. Abroad
+much used by mill-and wheelwrights. A small tree, largest in the
+Southwest, but found in nearly all parts of the eastern United States.
+
+
+                     BOIS D'ARC (See Osage Orange)
+
+
+                                BUCKEYE
+
+Wood light, soft, not strong, often quite tough, of fine, uniform
+texture and creamy white color. It shrinks considerably in drying, but
+works well and stands well. Used for woodenware, artificial limbs,
+paper pulp, and locally also for building construction.
+
+=19. Ohio Buckeye= (_Æsculus glabra_) (Horse Chestnut, Fetid Buckeye).
+Small-sized tree, scattered, never forming forests. Heartwood white,
+sapwood pale brown. Wood light, soft, not strong, often quite tough
+and close-grained. Alleghanies, Pennsylvania to Oklahoma.
+
+=20. Sweet Buckeye= (_Æsculus octandra_ var. _flava_) (Horse Chestnut).
+Small-sized tree, scattered, never forming forests. Wood in its
+quality and uses similar to the preceding. Alleghanies, Pennsylvania
+to Texas.
+
+
+                              BUCKTHORNE
+
+=21. Buckthorne= (_Rhanmus Caroliniana_) (Indian Cherry). Small-sized
+tree. Heartwood light brown, sapwood almost white. Wood light, hard,
+close-grained. Does not enter the markets to any great extent. Found
+along the borders of streams in rich bottom lands. Its northern limits
+is Long Island, where it is only a shrub; it becomes a tree only in
+southern Arkansas and adjoining regions.
+
+
+                               BUTTERNUT
+
+=22. Butternut= (_Juglans cinerea_) (White Walnut, White Mahogany,
+Walnut). Medium-sized tree, scattered, never forming forests. Wood
+very similar to black walnut, but light, quite soft, and not strong.
+Heartwood light gray-brown, darkening with exposure; sapwood nearly
+white, coarse-grained, compact structure, easily worked, and
+susceptible to high polish. Has similar grain to black walnut and when
+stained is a very good imitation. Is much used for inside work, and
+very durable. Used chiefly for finishing lumber, cabinet work, boat
+finish and fixtures, and for furniture. Butternut furniture is often
+sold as circassian walnut. Largest and most common in the Ohio basin.
+Maine to Minnesota and southward to Georgia and Alabama.
+
+
+                                CATALPA
+
+The catalpa is a tree which was planted about 25 years ago as a
+commercial speculation in Iowa, Kansas, and Nebraska. Its native
+habitat was along the rivers Ohio and lower Wabash, and a century ago
+it gained a reputation for rapid growth and durability, but did not
+grow in large quantities. As a railway tie, experiments have left no
+doubt as to its resistance to decay; it stands abrasion as well as the
+white oak (_Quercus alba_), and is superior to it in longevity.
+Catalpa is a tree singularly free from destructive diseases. Wood cut
+from the living tree is one of the most durable timbers known. In
+spite of its light porous structure it resists the weathering
+influences and the attacks of wood-destroying fungi to a remarkable
+degree. No fungus has yet been found which will grow in the dead
+timber, and for fence posts this wood has no equal, lasting longer
+than almost any other species of timber. The wood is rather soft and
+coarse in texture, the tree is of slow growth, and the brown colored
+heartwood, even of very young trees, forms nearly three-quarters of
+their volume. There is only about one-quarter inch of sapwood in a
+9-inch tree.
+
+=23. Catalpa= (_Catalpa speciosa_ var. _bignonioides_) (Indian Bean).
+Medium-sized tree. Heartwood light brown, sapwood nearly white. Wood
+light, soft, not strong, brittle, very durable in contact with the
+soil, of coarse texture. Used chiefly for railway ties, telegraph
+poles, and fence posts, but well suited for a great variety of uses.
+Lower basin of the Ohio River, locally common. Extensively planted,
+and therefore promising to become of some importance.
+
+
+                                CHERRY
+
+=24. Cherry= (_Prunus serotina_) (Wild Cherry, Black Cherry, Rum
+Cherry). Wood heavy, hard, strong, of fine texture. Sapwood yellowish
+white, heartwood reddish to brown. The wood shrinks considerably in
+drying, works well and stands well, has a fine satin-like luster, and
+takes a fine polish which somewhat resembles mahogany, and is much
+esteemed for its beauty. Cherry is chiefly used as a decorative
+interior finishing lumber, for buildings, cars and boats, also for
+furniture and in turnery, for musical instruments, walking sticks,
+last blocks, and woodenware. It is becoming too costly for many
+purposes for which it is naturally well suited. The lumber-furnishing
+cherry of the United States, the wild black cherry, is a small to
+medium-sized tree, scattered through many of the broad-leaved trees of
+the western slope of the Alleghanies, but found from Michigan to
+Florida, and west to Texas. Other species of this genus, as well as
+the hawthornes (_Prunus cratoegus_) and wild apple (_Pyrus_), are not
+commonly offered in the markets. Their wood is of the same character
+as cherry, often finer, but in smaller dimensions.
+
+=25. Red Cherry= (_Prunus Pennsylvanica_) (Wild Red Cherry, Bird
+Cherry). Small-sized tree. Heartwood light brown, sapwood pale yellow.
+Wood light, soft, and close-grained. Uses similiar to the preceding,
+common throughout the Northern States, reaching its greatest size on
+the mountains of Tennessee.
+
+
+                               CHESTNUT
+
+The chestnut is a long-lived tree, attaining an age of from 400 to 600
+years, but trees over 100 years are usually hollow. It grows quickly,
+and sprouts from a chestnut stump (Coppice Chestnut) often attain a
+height of 8 feet in the first year. It has a fairly cylindrical stem,
+and often grows to a height of 100 feet and over. Coppice chestnut,
+that is, chestnut grown on an old stump, furnishes better timber for
+working than chestnut grown from the nut, it is heavier, less spongy,
+straighter in grain, easier to split, and stands exposure longer.
+
+=26. Chestnut= (_Castanea vulgaris_ var. _Americana_). Medium-to
+large-sized tree, never forming forests. Wood is light, moderately
+hard, stiff, elastic, not strong, but very durable when in contact
+with the soil, of coarse texture. Sapwood light, heartwood darker
+brown, and is readily distinguishable from the sapwood, which very
+early turns into heartwood. It shrinks and checks considerably in
+drying, works easily, stands well. The annual rings are very distinct,
+medullary rays very minute and not visible to the naked eye. Used in
+cooperage, for cabinetwork, agricultural implements, railway ties,
+telegraph poles, fence posts, sills, boxes, crates, coffins,
+furniture, fixtures, foundation for veneer, and locally in heavy
+construction. Very common in the Alleghanies. Occurs from Maine to
+Michigan and southward to Alabama.
+
+=27. Chestnut= (_Castanea dentata_ var. _vesca_). Medium-sized tree,
+never forming forests, not common. Heartwood brown color, sapwood
+lighter shade, coarse-grained. Wood and uses similar to the preceding.
+Occurs scattered along the St. Lawrence River, and even there is met
+with only in small quantities.
+
+=28. Chinquapin= (_Castanea pumila_). Medium- to small-sized tree, with
+wood slightly heavier, but otherwise similiar to the preceding. Most
+common in Arkansas, but with nearly the same range as _Castanea
+vulgaris_.
+
+=29. Chinquapin= (_Castanea chrysophylla_). A medium-sized tree of the
+western ranges of California and Oregon.
+
+
+                              COFFEE TREE
+
+=30. Coffee Tree= (_Gymnocladus dioicus_) (Coffee Nut, Stump Tree). A
+medium- to large-sized tree, not common. Wood heavy, hard, strong,
+very stiff, of coarse texture, and durable. Sapwood yellow, heartwood
+reddish brown, shrinks and checks considerably in drying, works well
+and stands well, and takes a fine polish. It is used to a limited
+extent in cabinetwork and interior finish. Pennsylvania to Minnesota
+and Arkansas.
+
+
+                        COTTONWOOD (See Poplar)
+
+
+                              CRAB APPLE
+
+=31. Crab Apple= (_Pyrus coronaria_) (Wild Apple, Fragrant Crab).
+Small-sized tree. Heartwood reddish brown, sapwood yellow. Wood heavy,
+hard, not strong, close-grained. Used principally for tool handles and
+small domestic articles. Most abundant in the middle and western
+states, reaches its greatest size in the valleys of the lower Ohio
+basin.
+
+
+                     CUCUMBER TREE (See Magnolia)
+
+
+                                DOGWOOD
+
+=32. Dogwood= (_Cornus florida_) (American Box). Small to medium-sized
+tree. Attains a height of about 30 feet and about 12 inches in
+diameter. The heartwood is a red or pinkish color, the sapwood, which
+is considerable, is a creamy white. The wood has a dull surface and
+very fine grain. It is valuable for turnery, tool handles, and
+mallets, and being so free from silex, watchmakers use small splinters
+of it for cleaning out the pivot holes of watches, and opticians for
+removing dust from deep-seated lenses. It is also used for butchers'
+skewers, and shuttle blocks and wheel stock, and is suitable for
+turnery and inlaid work. Occurs scattered in all the broad-leaved
+forests of our country; very common.
+
+
+                                  ELM
+
+Wood heavy, hard, strong, elastic, very tough, moderately durable in
+contact with the soil, commonly cross-grained, difficult to split and
+shape, warps and checks considerably in drying, but stands well if
+properly seasoned. The broad sapwood whitish, heartwood light brown,
+both with shades of gray and red. On split surfaces rough, texture
+coarse to fine, capable of high polish. Elm for years has been the
+principal wood used in slack cooperage for barrel staves, also in the
+construction of cars, wagons, etc., in boat building, agricultural
+implements and machinery, in saddlery and harness work, and
+particularly in the manufacture of all kinds of furniture, where the
+beautiful figures, especially those of the tangential or bastard
+section, are just beginning to be appreciated. The elms are medium- to
+large-sized trees, of fairly rapid growth, with stout trunks; they
+form no forests of pure growth, but are found scattered in all the
+broad-leaved woods of our country, sometimes forming a considerable
+portion of the arborescent growth.
+
+=33. White Elm= (_Ulmus Americana_) (American Elm, Water Elm). Medium-
+to large-sized tree. Wood in its quality and uses as stated above.
+Common. Maine to Minnesota, southward to Florida and Texas.
+
+=34. Rock Elm= (_Ulmus racemosa_) (Cork Elm, Hickory Elm, White Elm,
+Cliff Elm). Medium- to large-sized tree of rapid growth. Heartwood
+light brown, often tinged with red, sapwood yellowish or greenish
+white, compact structure, fibres interlaced. Wood heavy, hard, very
+tough, strong, elastic, difficult to split, takes a fine polish. Used
+for agricultural implements, automobiles, crating, boxes, cooperage,
+tool handles, wheel stock, bridge timbers, sills, interior finish,
+and maul heads. Fairly free from knots and has only a small quantity
+of sapwood. Michigan, Ohio, from Vermont to Iowa, and southward to
+Kentucky.
+
+=35. Red Elm= (_Ulmus fulva_ var. _pubescens_) (Slippery Elm, Moose
+Elm). The red or slippery elm is not as large a tree as the white elm
+(_Ulmus Americana_), though it occasionally attains a height of 135
+feet and a diameter of 4 feet. It grows tall and straight, and thrives
+in river valleys. The wood is heavy, hard, strong, tough, elastic,
+commonly cross-grained, moderately durable in contact with the soil,
+splits easily when green, works fairly well, and stands well if
+properly handled. Careful seasoning and handling are essential for the
+best results. Trees can be utilized for posts when very small. When
+green the wood rots very quickly in contact with the soil. Poles for
+posts should be cut in summer and peeled and dried before setting. The
+wood becomes very tough and pliable when steamed, and is of value for
+sleigh runners and for ribs of canoes and skiffs. Together with white
+elm (_Ulmus Americana_) it is extensively used for barrel staves in
+slack cooperage and also for furniture. The thick, viscous inner bark,
+which gives the tree its descriptive name, is quite palatable,
+slightly nutritious, and has a medicinal value. Found chiefly along
+water courses. New York to Minnesota, and southward to Florida and
+Texas.
+
+=36. Cedar Elm= (_Ulmus crassifolia_). Medium- to small-sized tree,
+locally quite common. Arkansas and Texas.
+
+=37. Winged Elm= (_Ulmus alata_) (Wahoo). Small-sized tree, locally
+quite common. Heartwood light brown, sapwood yellowish white. Wood
+heavy, hard, tough, strong, and close-grained. Arkansas, Missouri, and
+eastern Virginia.
+
+    [Illustration: Fig. 10. A Large Red Gum.]
+
+
+                                  GUM
+
+This general term applies to three important species of gum in the
+South, the principal one usually being distinguished as "red" or
+"sweet" gum (see Fig. 10). The next in importance being the "tupelo"
+or "bay poplar," and the least of the trio is designated as "black" or
+"sour" gum (see Fig. 11). Up to the year 1900 little was known of gum
+as a wood for cooperage purposes, but by the continued advance in
+price of the woods used, a few of the most progressive manufacturers,
+looking into the future, saw that the supply of the various woods in
+use was limited, that new woods would have to be sought, and gum was
+looked upon as a possible substitute, owing to its cheapness and
+abundant supply. No doubt in the future this wood will be used to a
+considerable extent in the manufacture of both "tight" and "slack"
+cooperage. In the manufacture of the gum, unless the knives and saws
+are kept very sharp, the wood has a tendency to break out, the corners
+splitting off; and also, much difficulty has been experienced in
+seasoning and kiln-drying.
+
+    [Illustration: Fig. 11. A Tupelo Gum Slough.]
+
+In the past, gum, having no marketable value, has been left standing
+after logging operations, or, where the land has been cleared for
+farming, the trees have been "girdled" and allowed to rot, and then
+felled and burned as trash. Now, however, that there is a market for
+this species of timber, it will be profitable to cut the gum with the
+other hardwoods, and this species of wood will come in for a greater
+share of attention than ever before.
+
+=38. Red Gum= (_Liquidamber styraciflua_) (Sweet Gum, Hazel Pine, Satin
+Walnut, Liquidamber, Bilsted). The wood is about as stiff and as
+strong as chestnut, rather heavy, it splits easily and is quite brash,
+commonly cross-grained, of fine texture, and has a large proportion of
+whitish sapwood, which decays rapidly when exposed to the weather; but
+the reddish brown heartwood is quite durable, even in the ground. The
+external appearance of the wood is of fine grain and smooth, close
+texture, but when broken the lines of fracture do not run with
+apparent direction of the growth; possibly it is this unevenness of
+grain which renders the wood so difficult to dry without twisting and
+warping. It has little resiliency; can be easily bent when steamed,
+and when properly dried will hold its shape. The annual rings are not
+distinctly marked, medullary rays fine and numerous. The green wood
+contains much water, and consequently is heavy and difficult to float,
+but when dry it is as light as basswood. The great amount of water in
+the green wood, particularly in the sap, makes it difficult to season
+by ordinary methods without warping and twisting. It does not check
+badly, is tasteless and odorless, and when once seasoned, swells and
+shrinks but little unless exposed to the weather. Used for boat
+finish, veneers, cabinet work, furniture, fixtures, interior
+decoration, shingles, paving blocks, woodenware, cooperage, machinery
+frames, refrigerators, and trunk slats.
+
+
+                           Range of Red Gum
+
+Red gum is distributed from Fairfield County, Conn., to southeastern
+Missouri, through Arkansas and Oklahoma to the valley of the Trinity
+River in Texas, and eastward to the Atlantic coast. Its commercial
+range is restricted, however, to the moist lands of the lower Ohio and
+Mississippi basins and of the Southeastern coast. It is one of the
+commonest timber trees in the hardwood bottoms and drier swamps of the
+South. It grows in mixture with ash, cottonwood and oak (see Fig. 12).
+It is also found to a considerable extent on the lower ridges and
+slopes of the southern Appalachians, but there it does not reach
+merchantable value and is of little importance. Considerable
+difference is found between the growth in the upper Mississippi
+bottoms and that along the rivers on the Atlantic coast and on the
+Gulf. In the latter regions the bottoms are lower, and consequently
+more subject to floods and to continued overflows (see Fig. 11). The
+alluvial deposit is also greater, and the trees grow considerably
+faster. Trees of the same diameter show a larger percentage of sapwood
+there than in the upper portions of the Mississippi Valley. The
+Mississippi Valley hardwood trees are for the most part considerably
+older, and reach larger dimensions than the timber along the coast.
+
+
+                          Form of the Red Gum
+
+In the best situations red gum reaches a height of 150 feet, and a
+diameter of 5 feet. These dimensions, however are unusual. The stem is
+straight and cylindrical, with dark, deeply-furrowed bark, and
+branches often winged with corky ridges. In youth, while growing
+vigorously under normal conditions, it assumes a long, regular,
+conical crown, much resembling the form of a conifer (see Fig. 12).
+After the tree has attained its height growth, however, the crown
+becomes rounded, spreading and rather ovate in shape. When growing in
+the forest the tree prunes itself readily at an early period, and
+forms a good length of clear stem, but it branches strongly after
+making most of its height growth. The mature tree is usually forked,
+and the place where the forking commences determines the number of
+logs in the tree or its merchantable length, by preventing cutting to
+a small diameter in the top. On large trees the stem is often not less
+than eighteen inches in diameter where the branching begins. The
+over-mature tree is usually broken and dry topped, with a very
+spreading crown, in consequence of new branches being sent out.
+
+
+                         Tolerance of Red Gum
+
+Throughout its entire life red gum is intolerant in shade, there are
+practically no red seedlings under the dense forest cover of the
+bottom land, and while a good many may come up under the pine forest
+on the drier uplands, they seldom develop into large trees. As a rule
+seedlings appear only in clearings or in open spots in the forest. It
+is seldom that an over-topped tree is found, for the gum dies quickly
+if suppressed, and is consequently nearly always a dominant or
+intermediate tree. In a hardwood bottom forest the timber trees are
+all of nearly the same age over considerable areas, and there is
+little young growth to be found in the older stands. The reason for
+this is the intolerance of most of the swamp species. A scale of
+intolerance containing the important species, and beginning with the
+most light-demanding, would run as follows: Cottonwood, sycamore, red
+gum, white elm, white ash, and red maple.
+
+
+                    Demands upon Soil and Moisture
+
+While the red gum grows in various situations, it prefers the deep,
+rich soil of the hardwood bottoms, and there reaches its best
+development (see Fig. 10). It requires considerable soil moisture,
+though it does not grow in the wetter swamps, and does not thrive on
+dry pine land. Seedlings, however, are often found in large numbers on
+the edges of the uplands and even on the sandy pine land, but they
+seldom live beyond the pole stage. When they do, they form small,
+scrubby trees that are of little value. Where the soil is dry the tree
+has a long tap root. In the swamps, where the roots can obtain water
+easily, the development of the tap root is poor, and it is only
+moderate on the glade bottom lands, where there is considerable
+moisture throughout the year, but no standing water in the summer
+months.
+
+
+                        Reproduction of Red Gum
+
+    [Illustration: Fig. 12. Second Growth Red Gum, Ash,
+    Cottonwood, and Sycamore.]
+
+Red gum reproduces both by seed and by sprouts (see Fig. 12). It
+produces seed fairly abundantly every year, but about once in three
+years there is an extremely heavy production. The tree begins to bear
+seed when twenty-five to thirty years old, and seeds vigorously up to
+an age of one hundred and fifty years, when its productive power
+begins to diminish. A great part of the seed, however, is abortive.
+Red gum is not fastidious in regard to its germinating bed; it comes
+up readily on sod in old fields and meadows, on decomposing humus in
+the forest, or on bare clay-loam or loamy sand soil. It requires a
+considerable degree of light, however, and prefers a moist seed bed.
+The natural distribution of the seed takes place for several hundred
+feet from the seed trees, the dissemination depending almost entirely
+on the wind. A great part of the seed falls on the hardwood bottom
+when the land is flooded, and is either washed away or, if already in
+the ground and germinating, is destroyed by the long-continued
+overflow. After germinating, the red gum seedling demands, above
+everything else, abundant light for its survival and development. It
+is for this reason that there is very little growth of red gum, either
+in the unculled forest or on culled land, where, as is usually the
+case, a dense undergrowth of cane, briers, and rattan is present.
+Under the dense underbrush of cane and briers throughout much of the
+virgin forest, reproduction of any of the merchantable species is of
+course impossible. And even where the land has been logged over, the
+forest is seldom open enough to allow reproduction of cottonwood and
+red gum. Where, however, seed trees are contiguous to pastures or
+cleared land, scattered seedlings are found springing up in the open,
+and where openings occur in the forest, there are often large numbers
+of red gum seedlings, the reproduction generally occurring in groups.
+But over the greater part of the Southern hardwood bottom land forest
+reproduction is very poor. The growth of red gum during the early part
+of its life, and up to the time it reaches a diameter of eight inches
+breast-high, is extremely rapid, and, like most of the intolerant
+species, it attains its height growth at an early period. Gum sprouts
+readily from the stump, and the sprouts surpass the seedlings in rate
+of height growth for the first few years, but they seldom form large
+timber trees. Those over fifty years of age seldom sprout. For this
+reason sprout reproduction is of little importance in the forest. The
+principal requirements of red gum, then, are a moist, fairly rich soil
+and good exposure to light. Without these it will not reach its best
+development.
+
+    [Illustration: Fig. 13. A Cypress Slough in the Dry Season.]
+
+
+                         Second-Growth Red Gum
+
+Second-growth red gum occurs to any considerable extent only on land
+which has been thoroughly cleared. Throughout the South there is a
+great deal of land which was in cultivation before the Civil War, but
+which during the subsequent period of industrial depression was
+abandoned and allowed to revert to forest. These old fields now mostly
+covered with second-growth forest, of which red gum forms an
+important part (see Fig. 12). Frequently over fifty per cent of the
+stand consists of this species, but more often, and especially on the
+Atlantic coast, the greater part is of cottonwood or ash. These stands
+are very dense, and the growth is extremely rapid. Small stands of
+young growth are also often found along the edges of cultivated
+fields. In the Mississippi Valley the abandoned fields on which young
+stands have sprung up are for the most part being rapidly cleared
+again. The second growth here is considered of little value in
+comparison with the value of the land for agricultural purposes. In
+many cases, however, the farm value of the land is not at present
+sufficient to make it profitable to clear it, unless the timber cut
+will at least pay for the operation. There is considerable land upon
+which the second growth will become valuable timber within a few
+years. Such land should not be cleared until it is possible to utilize
+the timber.
+
+=39. Tupelo Gum= (_Nyssa aquatica_) (Bay Poplar, Swamp Poplar, Cotton
+Gum, Hazel Pine, Circassian Walnut, Pepperidge, Nyssa). The close
+similarity which exists between red and tupelo gum, together with the
+fact that tupelo is often cut along with red gum, and marketed with
+the sapwood of the latter, makes it not out of place to give
+consideration to this timber. The wood has a fine, uniform texture, is
+moderately hard and strong, is stiff, not elastic, very tough and hard
+to split, but easy to work with tools. Tupelo takes glue, paint, or
+varnish well, and absorbs very little of the material. In this respect
+it is equal to yellow poplar and superior to cottonwood. The wood is
+not durable in contact with ground, and requires much care in
+seasoning. The distinction between the heartwood and sapwood of this
+species is marked. The former varies in color from a dull gray to a
+dull brown; the latter is whitish or light yellow like that of poplar.
+The wood is of medium weight, about thirty-two pounds per cubic foot
+when dry, or nearly that of red gum and loblolly pine. After
+seasoning it is difficult to distinguish the better grades of sapwood
+from poplar. Owing to the prejudice against tupelo gum, it was until
+recently marketed under such names as bay poplar, swamp poplar, nyssa,
+cotton gum, circassian walnut, and hazel pine. Since it has become
+evident that the properties of the wood fit it for many uses, the
+demand for tupelo has largely increased, and it is now taking rank
+with other standard woods under its rightful name. Heretofore the
+quality and usefulness of this wood were greatly underestimated, and
+the difficulty of handling it was magnified. Poor success in seasoning
+and kiln-drying was laid to defects of the wood itself, when, as a
+matter of fact, the failures were largely due to the absence of proper
+methods in handling. The passing of this prejudice against tupelo is
+due to a better understanding of the characteristics and uses of the
+wood. Handled in the way in which its particular character demands,
+tupelo is a wood of much value.
+
+
+                          Uses of Tupelo Gum
+
+Tupelo gum is now used in slack cooperage, principally for heading. It
+is used extensively for house flooring and inside finishing, such as
+mouldings, door jambs, and casings. A great deal is now shipped to
+European countries, where it is highly valued for different classes of
+manufacture. Much of the wood is used in the manufacture of boxes,
+since it works well upon rotary veneer machines. There is also an
+increasing demand for tupelo for laths, wooden pumps, violin and organ
+sounding boards, coffins, mantelwork, conduits and novelties. It is
+also used in the furniture trade for backing, drawers, and panels.
+
+
+                          Range of Tupelo Gum
+
+Tupelo occurs throughout the coastal region of the Atlantic States,
+from southern Virginia to northern Florida, through the Gulf States to
+the valley of the Nueces River in Texas, through Arkansas and southern
+Missouri to western Kentucky and Tennessee, and to the valley of the
+lower Wabash River. Tupelo is being extensively milled at present only
+in the region adjacent to Mobile Ala., and in southern and central
+Louisiana, where it occurs in large merchantable quantities, attaining
+its best development in the former locality. The country in this
+locality is very swampy (see Fig. 11), and within a radius of one
+hundred miles tupelo gum is one of the principal timber trees. It
+grows only in the swamps and wetter situations (see Fig. 11), often in
+mixture with cypress, and in the rainy season it stands in from two to
+twenty feet of water.
+
+=40. Black Gum= (_Nyssa sylvatica_) (Sour Gum). Black gum is not cut to
+much extent, owing to its less abundant supply and poorer quality, but
+is used for repair work on wagons, for boxes, crates, wagon hubs,
+rollers, bowls, woodenware, and for cattle yokes and other purposes
+which require a strong, non-splitting wood. Heartwood is light brown
+in color, often nearly white; sapwood hardly distinguishable, fine
+grain, fibres interwoven. Wood is heavy, not hard, difficult to work,
+strong, very tough, checks and warps considerably in drying, not
+durable. It is distributed from Maine to southern Ontario, through
+central Michigan to southeastern Missouri, southward to the valley of
+the Brazos River in Texas, and eastward to the Kissimmee River and
+Tampa Bay in Florida. It is found in the swamps and hardwood bottoms,
+but is more abundant and of better size on the slightly higher ridges
+and hummocks in these swamps, and on the mountain slopes in the
+southern Alleghany region. Though its range is greater than that of
+either red or tupelo gum, it nowhere forms an important part of the
+forest.
+
+
+                               HACKBERRY
+
+=41. Hackberry= (_Celtis occidentalis_) (Sugar Berry, Nettle Tree). The
+wood is handsome, heavy, hard, strong, quite tough, of moderately fine
+texture, and greenish or yellowish color, shrinks moderately, works
+well and stands well, and takes a good polish. Used to some extent in
+cooperage, and in the manufacture of cheap furniture. Medium- to
+large-sized tree, locally quite common, largest in the lower
+Mississippi Valley. Occurs in nearly all parts of the eastern United
+States.
+
+
+                                HICKORY
+
+The hickories of commerce are exclusively North American and some of
+them are large and beautiful trees of 60 to 70 feet or more in height.
+They are closely allied to the walnut, and the wood is very like
+walnut in grain and color, though of a somewhat darker brown. It is
+one of the finest of American hardwoods in point of strength; in
+toughness it is superior to ash, rather coarse in texture, smooth and
+of straight grain, very heavy and strong as well as elastic and
+tenacious, but decays rapidly, especially the sapwood when exposed to
+damp and moisture, and is very liable to attack from worms and boring
+insects. The cross-section of hickory is peculiar, the annual rings
+appear like fine lines instead of like the usual pores, and the
+medullary rays, which are also very fine but distinct, in crossing
+these form a peculiar web-like pattern which is one of the
+characteristic differences between hickory and ash. Hickory is rarely
+subjected to artificial treatment, but there is this curious fact in
+connection with the wood, that, contrary to most other woods, creosote
+is only with difficulty injected into the sap, although there is no
+difficulty in getting it into the heartwood. It dries slowly, shrinks
+and checks considerably in seasoning; is not durable in contact with
+the soil or if exposed. Hickory excels as wagon and carriage stock,
+for hoops in cooperage, and is extensively used in the manufacture of
+implements and machinery, for tool handles, timber pins, harness work,
+dowel pins, golf clubs, and fishing rods. The hickories are tall trees
+with slender stems, never forming forests, occasionally small groves,
+but usually occur scattered among other broad-leaved trees in suitable
+localities. The following species all contribute more or less to the
+hickory of the markets:
+
+=42. Shagbark Hickory= (_Hicoria ovata_) (Shellbark Hickory, Scalybark
+Hickory). A medium- to large-sized tree, quite common; the favorite
+among the hickories. Heartwood light brown, sapwood ivory or
+cream-colored. Wood close-grained, compact structure, annual rings
+clearly marked. Very hard, heavy, strong, tough, and flexible, but not
+durable in contact with the soil or when exposed. Used for
+agricultural implements, wheel runners, tool handles, vehicle parts,
+baskets, dowel pins, harness work, golf clubs, fishing rods, etc. Best
+developed in the Ohio and Mississippi basins; from Lake Ontario to
+Texas, Minnesota to Florida.
+
+=43. Mockernut Hickory= (_Hicoria alba_) (Black Nut Hickory, Black
+Hickory, Bull Nut Hickory, Big Bud Hickory, White Heart Hickory). A
+medium- to large-sized tree. Wood in its quality and uses similar to
+the preceding. Its range is the same as that of _Hicoria ovata_.
+Common, especially in the South.
+
+=44. Pignut Hickory= (_Hicoria glabra_) (Brown Hickory, Black Hickory,
+Switchbud Hickory). A medium- to large-sized tree. Heavier and
+stronger than any of the preceding. Heartwood light to dark brown,
+sapwood nearly white. Abundant, all eastern United States.
+
+=45. Bitternut Hickory= (_Hicoria minima_) (Swamp Hickory). A
+medium-sized tree, favoring wet localities. Heartwood light brown,
+sapwood lighter color. Wood in its quality and uses not so valuable as
+_Hicoria ovata_, but is used for the same purposes. Abundant, all
+eastern United States.
+
+=46. Pecan= (_Hicoria pecan_) (Illinois Nut). A large tree, very common
+in the fertile bottoms of the western streams. Indiana to Nebraska and
+southward to Louisiana and Texas.
+
+
+                                 HOLLY
+
+=47. Holly= (_Ilex opaca_). Small to medium-sized tree. Wood of medium
+weight, hard, strong, tough, of exceedingly fine grain, closer in
+texture than most woods, of white color, sometimes almost as white as
+ivory; requires great care in its treatment to preserve the whiteness
+of the wood. It does not readily absorb foreign matter. Much used by
+turners and for all parts of musical instruments, for handles on whips
+and fancy articles, draught-boards, engraving blocks, cabinet work,
+etc. The wood is often dyed black and sold as ebony; works well and
+stands well. Most abundant in the lower Mississippi Valley and Gulf
+States, but occurring eastward to Massachusetts and north to Indiana.
+
+=48. Holly= (_Ilex monticolo_) (Mountain Holly). Small-sized tree. Wood
+in its quality and uses similar to the preceding, but is not very
+generally known. It is found in the Catskill Mountains and extends
+southward along the Alleghanies as far as Alabama.
+
+
+                     HORSE CHESTNUT (See Buckeye)
+
+
+                               IRONWOOD
+
+=49. Ironwood= (_Ostrya Virginiana_) (Hop Hornbeam, Lever Wood).
+Small-sized tree, common. Heartwood light brown tinged with red,
+sapwood nearly white. Wood heavy, tough, exceedingly close-grained,
+very strong and hard, durable in contact with the soil, and will take
+a fine polish. Used for small articles like levers, handles of tools,
+mallets, etc. Ranges throughout the United States east of the Rocky
+Mountains.
+
+
+                                LAUREL
+
+=50. Laurel= (_Umbellularia Californica_) (Myrtle). A Western tree,
+produces timber of light brown color of great size and beauty, and is
+very valuable for cabinet and inside work, as it takes a fine polish.
+California and Oregon, coast range of the Sierra Nevada Mountains.
+
+
+                                LOCUST
+
+=51. Black Locust= (_Robinia pseudacacia_) (Locust, Yellow Locust,
+Acacia). Small to medium-sized tree. Wood very heavy, hard, strong,
+and tough, rivalling some of the best oak in this latter quality. The
+wood has great torsional strength, excelling most of the soft woods in
+this respect, of coarse texture, close-grained and compact structure,
+takes a fine polish. Annual rings clearly marked, very durable in
+contact with the soil, shrinks and checks considerably in drying, the
+very narrow sapwood greenish yellow, the heartwood brown, with shades
+of red and green. Used for wagon hubs, trenails or pins, but
+especially for railway ties, fence posts, and door sills. Also used
+for boat parts, turnery, ornamentations, and locally for construction.
+Abroad it is much used for furniture and farming implements and also
+in turnery. At home in the Alleghany Mountains, extensively planted,
+especially in the West.
+
+=52. Honey Locust= (_Gleditschia triacanthos_) (Honey Shucks, Locust,
+Black Locust, Brown Locust, Sweet Locust, False Acacia, Three-Thorned
+Acacia). A medium-sized tree. Wood heavy, hard, strong, tough, durable
+in contact with the soil, of coarse texture, susceptible to a good
+polish. The narrow sapwood yellow, the heartwood brownish red. So far,
+but little appreciated except for fences and fuel. Used to some extent
+for wheel hubs, and locally in rough construction. Found from
+Pennsylvania to Nebraska, and southward to Florida and Texas; locally
+quite abundant.
+
+=53. Locust= (_Robinia viscosa_) (Clammy Locust). Usually a shrub five
+or six feet high, but known to reach a height of 40 feet in the
+mountains of North Carolina, with the habit of a tree. Wood light
+brown, heavy, hard, and close-grained. Not used to much extent in
+manufacture. Range same as the preceding.
+
+
+                               MAGNOLIA
+
+=54. Magnolia= (_Magnolia glauca_) (Swamp Magnolia, Small Magnolia,
+Sweet Bay, Beaver Wood). Small-sized tree. Heartwood reddish brown,
+sap wood cream white. Sparingly used in manufacture. Ranges from Essex
+County, Mass., to Long Island, N. Y., from New Jersey to Florida, and
+west in the Gulf region to Texas.
+
+=55. Magnolia= (_Magnolia tripetala_) (Umbrella Tree). A small-sized
+tree. Wood in its quality similiar to the preceding. It may be easily
+recognized by its great leaves, twelve to eighteen inches long, and
+five to eight inches broad. This species as well as the preceding is
+an ornamental tree. Ranges from Pennsylvania southward to the Gulf.
+
+=56. Cucumber Tree= (_Magnolia accuminata_) (Tulip-wood, Poplar).
+Medium- to large-sized tree. Heartwood yellowish brown, sapwood almost
+white. Wood light, soft, satiny, close-grained, durable in contact
+with the soil, resembling and sometimes confounded with tulip tree
+(_Liriodendron tulipifera_) in the markets. The wood shrinks
+considerably, but seasons without much injury, and works and stands
+well. It bends readily when steamed, and takes stain and paint well.
+Used in cooperage, for siding, for panelling and finishing lumber in
+house, car and shipbuilding, etc., also in the manufacture of toys,
+culinary woodenware, and backing for drawers. Most common in the
+southern Alleghanies, but distributed from western New York to
+southern Illinois, south through central Kentucky and Tennessee to
+Alabama, and throughout Arkansas.
+
+
+                                 MAPLE
+
+Wood heavy, hard, strong, stiff, and tough, of fine texture,
+frequently wavy-grained, this giving rise to "curly" and "blister"
+figures which are much admired. Not durable in the ground, or when
+exposed. Maple is creamy white, with shades of light brown in the
+heartwood, shrinks moderately, seasons, works, and stands well, wears
+smoothly, and takes a fine polish. The wood is used in cooperage, and
+for ceiling, flooring, panelling, stairway, and other finishing lumber
+in house, ship, and car construction. It is used for the keels of
+boats and ships, in the manufacture of implements and machinery, but
+especially for furniture, where entire chamber sets of maple rival
+those of oak. Maple is also used for shoe lasts and other form blocks;
+for shoe pegs; for piano actions, school apparatus, for wood type in
+show bill printing, tool handles, in wood carving, turnery, and scroll
+work, in fact it is one of our most useful woods. The maples are
+medium-sized trees, of fairly rapid growth, sometimes form forests,
+and frequently constitute a large proportion of the arborescent
+growth. They grow freely in parts of the Northern Hemisphere, and are
+particularly luxuriant in Canada and the northern portions of the
+United States.
+
+=57. Sugar Maple= (_Acer saccharum_) (Hard Maple, Rock Maple). Medium-
+to large-sized tree, very common, forms considerable forests, and is
+especially esteemed. The wood is close-grained, heavy, fairly hard and
+strong, of compact structure. Heartwood brownish, sapwood lighter
+color; it can be worked to a satin-like surface and take a fine
+polish, it is not durable if exposed, and requires a good deal of
+seasoning. Medullary rays small but distinct. The "curly" or "wavy"
+varieties furnish wood of much beauty, the peculiar contortions of the
+grain called "bird's eye" being much sought after, and used as veneer
+for panelling, etc. It is used in all good grades of furniture,
+cabinetmaking, panelling, interior finish, and turnery; it is not
+liable to warp and twist. It is also largely used for flooring, for
+rollers for wringers and mangling machines, for which there is a large
+and increasing demand. The peculiarity known as "bird's eye," and
+which causes a difficulty in working the wood smooth, owing to the
+little pieces like knots lifting up, is supposed to be due to the
+action of boring insects. Its resistance to compression across the
+grain is higher than that of most other woods. Ranges from Maine to
+Minnesota, abundant, with birch, in the region of the Great Lakes.
+
+=58. Red Maple= (_Acer rubrum_) (Swamp Maple, Soft Maple, Water Maple).
+Medium-sized tree. Like the preceding but not so valuable. Scattered
+along water-courses and other moist localities. Abundant. Maine to
+Minnesota, southward to northern Florida.
+
+=59. Silver Maple= (_Acer saccharinum_) (Soft Maple, White Maple,
+Silver-Leaved Maple). Medium- to large-sized tree, common. Wood
+lighter, softer, and inferior to _Acer saccharum_, and usually offered
+in small quantities and held separate in the markets. Heartwood
+reddish brown, sapwood ivory white, fine-grained, compact structure.
+Fibres sometimes twisted, weaved, or curly. Not durable. Used in
+cooperage for woodenware, turnery articles, interior decorations and
+flooring. Valley of the Ohio, but occurs from Maine to Dakota and
+southward to Florida.
+
+=60. Broad-Leaved Maple= (_Acer macrophyllum_) (Oregon Maple).
+Medium-sized tree, forms considerable forests, and, like the preceding
+has a lighter, softer, and less valuable wood than _Acer saccharum_.
+Pacific Coast regions.
+
+=61. Mountain Maple= (_Acer spicatum_). Small-sized tree. Heartwood pale
+reddish brown, sapwood lighter color. Wood light, soft, close-grained,
+and susceptible of high polish. Ranges from lower St. Lawrence River
+to northern Minnesota and regions of the Saskatchewan River; south
+through the Northern States and along the Appalachian Mountains to
+Georgia.
+
+=62. Ash-Leaved Maple= (_Acer negundo_) (Box Elder). Medium- to
+large-sized tree. Heartwood creamy white, sapwood nearly white. Wood
+light, soft, close-grained, not strong. Used for woodenware and paper
+pulp. Distributed across the continent, abundant throughout the
+Mississippi Valley along banks of streams and borders of swamps.
+
+=63. Striped Maple= (_Acer Pennsylvanicum_) (Moose-wood). Small-sized
+tree. Produces a very white wood much sought after for inlaid and for
+cabinet work. Wood is light, soft, close-grained, and takes a fine
+polish. Not common. Occurs from Pennsylvania to Minnesota.
+
+
+                               MULBERRY
+
+=64. Red Mulberry= (_Morus rubra_). A small-sized tree. Wood moderately
+heavy, fairly hard and strong, rather tough, of coarse texture, very
+durable in contact with the soil. The sapwood whitish, heartwood
+yellow to orange brown, shrinks and checks considerably in drying,
+works well and stands well. Used in cooperage and locally in
+construction, and in the manufacture of farm implements. Common in the
+Ohio and Mississippi Valleys, but widely distributed in the eastern
+United States.
+
+
+                          MYRTLE (See Laurel)
+
+
+                                  OAK
+
+Wood very variable, usually very heavy and hard, very strong and
+tough, porous, and of coarse texture. The sapwood whitish, the
+heartwood "oak" to reddish brown. It shrinks and checks badly, giving
+trouble in seasoning, but stands well, is durable, and little subject
+to the attacks of boring insects. Oak is used for many purposes, and
+is the chief wood used for tight cooperage; it is used in
+shipbuilding, for heavy construction, in carpentry, in furniture, car
+and wagon work, turnery, and even in woodcarving. It is also used in
+all kinds of farm implements, mill machinery, for piles and wharves,
+railway ties, etc., etc. The oaks are medium- to large-sized trees,
+forming the predominant part of a large proportion of our
+broad-leaved forests, so that these are generally termed "oak
+forests," though they always contain considerable proportion of other
+kinds of trees. Three well-marked kinds--white, red, and live oak--are
+distinguished and kept separate in the markets. Of the two principal
+kinds "white oak" is the stronger, tougher, less porous, and more
+durable. "Red oak" is usually of coarser texture, more porous, often
+brittle, less durable, and even more troublesome in seasoning than
+white oak. In carpentry and furniture work red oak brings the same
+price at present as white oak. The red oaks everywhere accompany the
+white oaks, and, like the latter, are usually represented by several
+species in any given locality. "Live oak," once largely employed in
+shipbuilding, possesses all the good qualities, except that of size,
+of white oak, even to a greater degree. It is one of the heaviest,
+hardest, toughest, and most durable woods of this country. In
+structure it resembles the red oak, but is less porous.
+
+=65. White Oak= (_Quercus alba_) (American Oak). Medium-to large-sized
+tree. Heartwood light brown, sapwood lighter color. Annual rings well
+marked, medullary rays broad and prominent. Wood tough, strong, heavy,
+hard, liable to check in seasoning, durable in contact with the soil,
+takes a high polish, very elastic, does not shrink much, and can be
+bent to any form when steamed. Used for agricultural implements, tool
+handles, furniture, fixtures, interior finish, car and wagon
+construction, beams, cabinet work, tight cooperage, railway ties,
+etc., etc. Because of the broad medullary rays, it is generally
+"quarter-sawn" for cabinet work and furniture. Common in the Eastern
+States, Ohio and Mississippi Valleys. Occurs throughout the eastern
+United States.
+
+=66. White Oak= (_Quercus durandii_). Medium- to small-sized tree. Wood
+in its quality and uses similiar to the preceding. Texas, eastward to
+Alabama.
+
+=67. White Oak= (_Quercus garryana_) (Western White Oak). Medium- to
+large-sized tree. Stronger, more durable, and wood more compact than
+_Quercus alba_. Washington to California.
+
+=68. White Oak= (_Quercus lobata_). Medium- to large-sized tree. Largest
+oak on the Pacific Coast. Wood in its quality and uses similar to
+_Quercus alba_, only it is finer-grained. California.
+
+=69. Bur Oak= (_Quercus macrocarpa_) (Mossy-Cup Oak, Over-Cup Oak).
+Large-sized tree. Heartwood "oak" brown, sapwood lighter color. Wood
+heavy, strong, close-grained, durable in contact with the soil. Used
+in ship- and boatbuilding, all sorts of construction, interior finish
+of houses, cabinet work, tight cooperage, carriage and wagon work,
+agricultural implements, railway ties, etc., etc. One of the most
+valuable and most widely distributed of American oaks, 60 to 80 feet
+in height, and, unlike most of the other oaks, adapts itself to
+varying climatic conditions. It is one of the most durable woods when
+in contact with the soil. Common, locally abundant. Ranges from
+Manitoba to Texas, and from the foot hills of the Rocky Mountains to
+the Atlantic Coast. It is the most abundant oak of Kansas and
+Nebraska, and forms the scattered forests known as "The oak openings"
+of Minnesota.
+
+=70. Willow Oak= (_Quercus phellos_) (Peach oak). Small to medium-sized
+tree. Heartwood pale reddish brown, sapwood lighter color. Wood heavy,
+hard, strong, coarse-grained. Occasionally used in construction. New
+York to Texas, and northward to Kentucky.
+
+=71. Swamp White Oak= (_Quercus bicolor_ var. _platanoides_).
+Large-sized tree. Heartwood pale brown, sapwood the same color. Wood
+heavy, hard, strong, tough, coarse-grained, checks considerably in
+seasoning. Used in construction, interior finish of houses,
+carriage-and boatbuilding, agricultural implements, in cooperage,
+railway ties, fencing, etc., etc. Ranges from Quebec to Georgia and
+westward to Arkansas. Never abundant. Most abundant in the Lake
+States.
+
+=72. Over-Cup Oak= (_Quercus lyrata_) (Swamp White Oak, Swamp Post Oak).
+Medium to large-sized tree, rather restricted, as it grows in the
+swampy districts of Carolina and Georgia. Is a larger tree than most
+of the other oaks, and produces an excellent timber, but grows in
+districts difficult of access, and is not much used. Lower Mississippi
+and eastward to Delaware.
+
+=73. Pin Oak= (_Quercus palustris_) (Swamp Spanish Oak, Water Oak).
+Medium- to large-sized tree. Heartwood pale brown with dark-colored
+sap wood. Wood heavy, strong, and coarse-grained. Common along the
+borders of streams and swamps, attains its greatest size in the valley
+of the Ohio. Arkansas to Wisconsin, and eastward to the Alleghanies.
+
+=74. Water Oak= (_Quercus aquatica_) (Duck Oak, Possum Oak). Medium- to
+large-sized tree, of extremely rapid growth. Eastern Gulf States,
+eastward to Delaware and northward to Missouri and Kentucky.
+
+=75. Chestnut Oak= (_Quercus prinus_) (Yellow Oak, Rock Oak, Rock
+Chestnut Oak). Heartwood dark brown, sapwood lighter color. Wood
+heavy, hard, strong, tough, close-grained, durable in contact with the
+soil. Used for railway ties, fencing, fuel, and locally for
+construction. Ranges from Maine to Georgia and Alabama, westward
+through Ohio, and southward to Kentucky and Tennessee.
+
+=76. Yellow Oak= (_Quercus acuminata_) (Chestnut Oak, Chinquapin Oak).
+Medium- to large-sized tree. Heartwood dark brown, sapwood pale brown.
+Wood heavy, hard, strong, close-grained, durable in contact with the
+soil. Used in the manufacture of wheel stock, in cooperage, for
+railway ties, fencing, etc., etc. Ranges from New York to Nebraska and
+eastern Kansas, southward in the Atlantic region to the District of
+Columbia, and west of the Alleghanies southward to the Gulf States.
+
+=77. Chinquapin Oak= (_Quercus prinoides_) (Dwarf Chinquapin Oak, Scrub
+Chestnut Oak). Small-sized tree. Heartwood light brown, sapwood darker
+color. Does not enter the markets to any great extent. Ranges from
+Massachusetts to North Carolina, westward to Missouri, Nebraska,
+Kansas, and eastern Texas. Reaches its best form in Missouri and
+Kansas.
+
+=78. Basket Oak= (_Quercus michauxii_) (Cow Oak). Large-sized tree.
+Locally abundant. Lower Mississippi and eastward to Delaware.
+
+=79. Scrub Oak= (_Quercus ilicifolia_ var. _pumila_) (Bear Oak).
+Small-sized tree. Heartwood light brown, sapwood darker color. Wood
+heavy, hard, strong, and coarse-grained. Found in New England and
+along the Alleghanies.
+
+=80. Post Oak= (_Quercus obtusiloda_ var. _minor_) (Iron Oak). Medium-
+to large-sized tree, gives timber of great strength. The color is of a
+brownish yellow hue, close-grained, and often superior to the white
+oak (_Quercus alba_) in strength and durability. It is used for posts
+and fencing, and locally for construction. Arkansas to Texas, eastward
+to New England and northward to Michigan.
+
+=81. Red Oak= (_Quercus rubra_) (Black Oak). Medium- to large-sized
+tree. Heartwood light brown to red, sapwood lighter color. Wood
+coarse-grained, well-marked annual rings, medullary rays few but
+broad. Wood heavy, hard, strong, liable to check in seasoning. It is
+found over the same range as white oak, and is more plentiful. Wood is
+spongy in grain, moderately durable, but unfit for work requiring
+strength. Used for agricultural implements, furniture, bob sleds,
+vehicle parts, boxes, cooperage, woodenware, fixtures, interior
+finish, railway ties, etc., etc. Common in all parts of its range.
+Maine to Minnesota, and southward to the Gulf.
+
+=82. Black Oak= (_Quercus tinctoria_ var. _velutina_) (Yellow Oak).
+Medium- to large-sized tree. Heartwood bright brown tinged with red,
+sapwood lighter color. Wood heavy, hard, strong, coarse-grained,
+checks considerably in seasoning. Very common in the Southern States,
+but occurring North as far as Minnesota, and eastward to Maine.
+
+=83. Barren Oak= (_Quercus nigra_ var. _marilandica_) (Black Jack, Jack
+Oak). Small-sized tree. Heartwood dark brown, sapwood lighter color.
+Wood heavy, hard, strong, coarse-grained, not valuable. Used in the
+manufacture of charcoal and for fuel. New York to Kansas and Nebraska,
+and southward to Florida. Rare in the North, but abundant in the
+South.
+
+=84. Shingle Oak= (_Quercus imbricaria_) (Laurel Oak). Small to
+medium-sized tree. Heartwood pale reddish brown, sapwood lighter
+color. Wood heavy, hard, strong, coarse-grained, checks considerably
+in drying. Used for shingles and locally for construction. Rare in the
+east, most abundant in the lower Ohio Valley. From New York to
+Illinois and southward. Reaches its greatest size in southern Illinois
+and Indiana.
+
+=85. Spanish Oak= (_Quercus digitata_ var. _falcata_) (Red Oak).
+Medium-sized tree. Heartwood light reddish brown, sapwood much
+lighter. Wood heavy, hard, strong, coarse-grained, and checks
+considerably in seasoning. Used locally for construction, and has high
+fuel value. Common in south Atlantic and Gulf region, but found from
+Texas to New York, and northward to Missouri and Kentucky.
+
+=86. Scarlet Oak= (_Quercus coccinea_). Medium- to large-sized tree.
+Heartwood light reddish-brown, sapwood darker color. Wood heavy, hard,
+strong, and coarse-grained. Best developed in the lower basin of the
+Ohio, but found from Minnesota to Florida.
+
+=87. Live Oak= (_Quercus virens_) (Maul Oak). Medium- to large-sized
+tree. Grows from Maryland to the Gulf of Mexico, and often attains a
+height of 60 feet and 4 feet in diameter. The wood is hard, strong,
+and durable, but of rather rapid growth, therefore not as good quality
+as _Quercus alba_. The live oak of Florida is now reserved by the
+United States Government for Naval purposes. Used for mauls and
+mallets, tool handles, etc., and locally for construction. Scattered
+along the coast from Maryland to Texas.
+
+=88. Live Oak= (_Quercus chrysolepis_) (Maul Oak, Valparaiso Oak).
+Medium- to small-sized tree. California.
+
+
+                             OSAGE ORANGE
+
+=89. Osage Orange= (_Maclura aurantiaca_) (Bois d'Arc). A small-sized
+tree of fairly rapid growth. Wood very heavy, exceedingly hard,
+strong, not tough, of moderately coarse texture, and very durable and
+elastic. Sapwood yellow, heartwood brown on the end face, yellow on
+the longitudinal faces, soon turning grayish brown if exposed. It
+shrinks considerably in drying, but once dry it stands unusually well.
+Much used for wheel stock, and wagon framing; it is easily split, so
+is unfit for wheel hubs, but is very suitable for wheel spokes. It is
+considered one of the timbers likely to supply the place of black
+locust for insulator pins on telegraph poles. Seems too little
+appreciated; it is well suited for turned ware and especially for
+woodcarving. Used for spokes, insulator pins, posts, railway ties,
+wagon framing, turnery, and woodcarving. Scattered through the rich
+bottoms of Arkansas and Texas.
+
+
+                                 PAPAW
+
+=90. Papaw= (_Asimina triloba_) (Custard Apple). Small-sized tree, often
+only a shrub, Heartwood pale, yellowish green, sapwood lighter color.
+Wood light, soft, coarse-grained, and spongy. Not used to any extent
+in manufacture. Occurs in eastern and central Pennsylvania, west as
+far as Michigan and Kansas, and south to Florida and Texas. Often
+forming dense thickets in the lowlands bordering the Mississippi
+River.
+
+
+                               PERSIMMON
+
+=91. Persimmon= (_Diospyros Virginiana_). Small to medium-sized tree.
+Wood very heavy, and hard, strong and tough; resembles hickory, but is
+of finer texture and elastic, but liable to split in working. The
+broad sapwood cream color, the heartwood brown, sometimes almost
+black. The persimmon is the Virginia date plum, a tree of 30 to 50
+feet high, and 18 to 20 inches in diameter; it is noted chiefly for
+its fruit, but it produces a wood of considerable value. Used in
+turnery, for wood engraving, shuttles, bobbins, plane stock, shoe lasts,
+and largely as a substitute for box (_Buxus sempervirens_)--especially
+the black or Mexican variety,--also used for pocket rules and drawing
+scales, for flutes and other wind instruments. Common, and best
+developed in the lower Ohio Valley, but occurs from New York to Texas
+and Missouri.
+
+
+                     POPLAR (See also Tulip Wood)
+
+Wood light, very soft, not strong, of fine texture, and whitish,
+grayish to yellowish color, usually with a satiny luster. The wood
+shrinks moderately (some cross-grained forms warp excessively), but
+checks very little in seasoning; is easily worked, but is not durable.
+Used in cooperage, for building and furniture lumber, for crates and
+boxes (especially cracker boxes), for woodenware, and paper pulp.
+
+=92. Cottonwood= (_Populus monilifera_, var. _angulata_) (Carolina
+Poplar). Large-sized tree, forms considerable forests along many of
+the Western streams, and furnishes most of the cottonwood of the
+market. Heartwood dark brown, sapwood nearly white. Wood light, soft,
+not strong, and close-grained (see Fig. 14). Mississippi Valley and
+West. New England to the Rocky Mountains.
+
+=93. Cottonwood= (_Populus fremontii_ var. _wislizeni_). Medium-to
+large-sized tree. Common. Wood in its quality and uses similiar to the
+preceding, but not so valuable. Texas to California.
+
+    [Illustration: Fig. 14. A Large Cottonwood. One of the
+    Associates of Red Gum.]
+
+=94. Black Cottonwood= (_Populus trichocarpa_ var. _heterophylla_)
+(Swamp Cottonwood, Downy Poplar). The largest deciduous tree of
+Washington. Very common. Heartwood dull brown, sapwood lighter brown.
+Wood soft, close-grained. Is now manufactured into lumber in the West
+and South, and used in interior finish of buildings. Northern Rocky
+Mountains and Pacific region.
+
+=95. Poplar= (_Populus grandidentata_) (Large-Toothed Aspen).
+Medium-sized tree. Heartwood light brown, sapwood nearly white. Wood
+soft and close-grained, neither strong nor durable. Chiefly used for
+wood pulp. Maine to Minnesota and southward along the Alleghanies.
+
+=96. White Poplar= (_Populus alba_) (Abele-Tree). Small to medium-sized
+tree. Wood in its quality and uses similar to the preceding. Found
+principally along banks of streams, never forming forests. Widely
+distributed in the United States.
+
+=97. Lombardy Poplar= (_Populus nigra italica_). Medium-to large-sized
+tree. This species is the first ornamental tree introduced into the
+United States, and originated in Afghanistan. Does not enter into the
+markets. Widely planted in the United States.
+
+=98. Balsam= (_Populus balsamifera_) (Balm of Gilead, Tacmahac). Medium-
+to large-sized tree. Heartwood light brown, sapwood nearly white. Wood
+light, soft, not strong, close-grained. Used extensively in the
+manufacture of paper pulp. Common all along the northern boundary of
+the United States.
+
+=99. Aspen= (_Populus tremuloides_) (Quaking Aspen). Small to
+medium-sized tree, often forming extensive forests, and covering
+burned areas. Heartwood light brown, sapwood nearly white. Wood light,
+soft, close-grained, neither strong nor durable. Chiefly used for
+woodenware, cooperage, and paper pulp. Maine to Washington and
+northward, and south in the western mountains to California and New
+Mexico.
+
+
+                           RED GUM (See Gum)
+
+
+                               SASSAFRAS
+
+=100. Sassafras= (_Sassafras sassafras_). Medium-sized tree, largest in
+the lower Mississippi Valley. Wood light, soft, not strong, brittle,
+of coarse texture, durable in contact with the soil. The sapwood
+yellow, the heartwood orange brown. Used to some extent in slack
+cooperage, for skiff- and boatbuilding, fencing, posts, sills, etc.
+Occurs from New England to Texas and from Michigan to Florida.
+
+
+                          SOUR GUM (See Gum)
+
+
+                               SOURWOOD
+
+=101. Sourwood= (_Oxydendrum arboreum_) (Sorrel-Tree). A slender tree,
+reaching the maximum height of 60 feet. Heartwood reddish brown,
+sapwood lighter color. Wood heavy, hard, strong, close-grained, and
+takes a fine polish. Ranges from Pennsylvania, along the Alleghanies,
+to Florida and Alabama, westward through Ohio to southern Indiana and
+southward through Arkansas and Louisiana to the Coast.
+
+
+                          SWEET GUM (See Gum)
+
+
+                               SYCAMORE
+
+=102. Sycamore= (_Platanus occidentalis_) (Buttonwood, Button-Ball Tree,
+Plane Tree, Water Beech). A large-sized tree, of rapid growth. One of
+the largest deciduous trees of the United States, sometimes attaining
+a height of 100 feet. It produces a timber that is moderately heavy,
+quite hard, stiff, strong, and tough, usually cross-grained; of coarse
+texture, difficult to split and work, shrinks moderately, but warps
+and checks considerably in seasoning, but stands well, and is not
+considered durable for outside work, or in contact with the soil. It
+has broad medullary rays, and much of the timber has a beautiful
+figure. It is used in slack cooperage, and quite extensively for
+drawers, backs, and bottoms, etc., in furniture work. It is also used
+for cabinet work, for tobacco boxes, crates, desks, flooring,
+furniture, ox-yokes, butcher blocks, and also for finishing lumber,
+where it has too long been underrated. Common and largest in the Ohio
+and Mississippi Valleys, at home in nearly all parts of the eastern
+United States.
+
+=103. Sycamore= (_Platanus racemosa_). The California species,
+resembling in its wood the Eastern form. Not used to any great extent.
+
+
+                              TULIP TREE
+
+=104. Tulip Tree= (_Liriodendron tulipifera_) (Yellow Poplar, Tulip
+Wood, White Wood, Canary Wood, Poplar, Blue Poplar, White Poplar,
+Hickory Poplar). A medium- to large-sized tree, does not form forests,
+but is quite common, especially in the Ohio basin. Wood usually light,
+but varies in weight, it is soft, tough, but not strong, of fine
+texture, and yellowish color. The wood shrinks considerably, but
+seasons without much injury, and works and stands extremely well.
+Heartwood light yellow or greenish brown, the sapwood is thin, nearly
+white, and decays rapidly. The heartwood is fairly durable when
+exposed to the weather or in contact with the soil. It bends readily
+when steamed, and takes stain and paint well. The mature forest-grown
+tree has a long, straight, cylindrical bole, clear of branches for at
+least two thirds of its length, surmounted by a short, open, irregular
+crown. When growing in the open, the tree maintains a straight stem,
+but the crown extends almost to the ground, and is of conical shape.
+Yellow poplar, or tulip wood, ordinarily grows to a height of from 100
+to 125 feet, with a diameter of from 3 to 6 feet, and a clear length
+of about 70 feet. Trees have been found 190 feet high and ten feet in
+diameter. Used in cooperage, for siding, for panelling and finishing
+lumber in houses, car- and shipbuilding, for sideboards, panels of
+wagons and carriages, for aeroplanes, for automobiles, also in the
+manufacture of furniture farm implements, machinery, for pump logs,
+and almost every kind of common woodenware, boxes shelving, drawers,
+etc., etc. Also in the manufacture of toys, culinary woodenware, and
+backing for veneer. It is in great demand throughout the vehicle and
+implement trade, and also makes a fair grade of wood pulp. In fact the
+tulip tree is one of the most useful of woods throughout the
+woodworking industry of this country. Occurs from New England to
+Missouri and southward to Florida.
+
+
+                           TUPELO (See Gum)
+
+
+                                WAAHOO
+
+=105. Waahoo= (_Evonymus atropurpureus_). (Burning Bush, Spindle Tree).
+A small-sized tree. Wood white, tinged with orange; heavy, hard,
+tough, and close-grained, works well and stands well. Used principally
+for arrows and spindles. Widely distributed. Usually a shrub six to
+ten feet high, becoming a tree only in southern Arkansas and Oklahoma.
+
+
+                                WALNUT
+
+=106. Black Walnut= (_Juglans nigra_) (Walnut). A large, beautiful, and
+quickly-growing tree, about 60 feet and upwards in height. Wood heavy,
+hard, strong, of coarse texture, very durable in contact with the
+soil. The narrow sapwood whitish, the heartwood dark, rich, chocolate
+brown, sometimes almost black; aged trees of fine quality bring fancy
+prices. The wood shrinks moderately in seasoning, works well and
+stands well, and takes a fine polish. It is quite handsome, and has
+been for a long time the favorite wood for cabinet and furniture
+making. It is used for gun-stocks, fixtures, interior decoration,
+veneer, panelling, stair newells, and all classes of work demanding a
+high priced grade of wood. Black walnut is a large tree with stout
+trunk, of rapid growth, and was formerly quite abundant throughout
+the Alleghany region. Occurs from New England to Texas, and from
+Michigan to Florida. Not common.
+
+
+                     WHITE WALNUT (See Butternut)
+
+
+               WHITE WOOD (See Tulip and also Basswood)
+
+
+                             WHITE WILLOW
+
+=107. White Willow= (_Salix alba_ var. _vitellina_) (Willow, Yellow
+Willow, Blue Willow). The wood is very soft, light, flexible, and
+fairly strong, is fairly durable in contact with the soil, works well
+and stands well when seasoned. Medium-sized tree, characterized by a
+short, thick trunk, and a large, rather irregular crown composed of
+many branches. The size of the tree at maturity varies with the
+locality. In the region where it occurs naturally, a height of 70 to
+80 feet, and a diameter of three to four feet are often attained. When
+planted in the Middle West, a height of from 50 to 60 feet, and a
+diameter of one and one-half to two feet are all that may be expected.
+When closely planted on moist soil, the tree forms a tall, slender
+stem, well cleared branches. Is widely naturalized in the United
+States. It is used in cooperage, for woodenware, for cricket and
+baseball bats, for basket work, etc. Charcoal made from the wood is
+used in the manufacture of gunpowder. It has been generally used for
+fence posts on the Northwestern plains, because of scarcity of better
+material. Well seasoned posts will last from four to seven years.
+Widely distributed throughout the United States.
+
+=108. Black Willow= (_Salix nigra_). Small-sized tree. Heartwood light
+reddish brown, sapwood nearly white. Wood soft, light, not strong,
+close-grained, and very flexible. Used in basket making, etc. Ranges
+from New York to Rocky Mountains and southward to Mexico.
+
+=109. Shining Willow= (_Salix lucida_). A small-sized tree. Wood in its
+quality and uses similiar to the preceding. Ranges from Newfoundland
+to Rocky Mountains and southward to Pennsylvania and Nebraska.
+
+=110. Perch Willow= (_Salix amygdaloides_) (Almond-leaf Willow). Small
+to medium-sized tree. Heartwood light brown, sapwood lighter color.
+Wood light, soft, flexible, not strong, close-grained. Uses similiar
+to the preceding. Follows the water courses and ranges across the
+continent; less abundant in New England than elsewhere. Common in the
+West.
+
+=111. Long-Leaf Willow= (_Salix fluviatilis_) (Sand Bar Willow). A
+small-sized tree. Ranges from the Arctic Circle to Northern Mexico.
+
+=112. Bebb Willow= (_Salix bebbiana_ var. _rostrata_). A small-sized
+tree. More abundant in British America than in the United States,
+where it ranges southward to Pennsylvania and westward to Minnesota.
+
+=113. Glaucous Willow= (_Salix discolor_) (Pussy Willow). A small-sized
+tree. Common along the banks of streams, and ranges from Nova Scotia
+to Manitoba, and south to Delaware; west to Indiana and northwestern
+Missouri.
+
+=114. Crack Willow= (_Salix fragilis_). A medium to large-sized tree.
+Wood is very soft, light, very flexible and fairly strong, is fairly
+durable in contact with the soil, works well and stands well. Used
+principally for basket making, hoops, etc., and to produce charcoal
+for gunpowder. Very common, and widely distributed in the United
+States.
+
+=115. Weeping Willow= (_Salix babylonica_). Medium- to large-sized tree.
+Wood similiar to _Salix nigra_, but not so valuable. Mostly an
+ornamental tree. Originally came from China. Widely planted in the
+United States.
+
+
+                              YELLOW WOOD
+
+=116. Yellow Wood= (_Cladrastis lutea_) (Virgilia). A small to
+medium-sized tree. Wood yellow to pale brown, heavy, hard,
+close-grained and strong. Not used to much extent in manufacturing.
+Not common. Found principally on the limestone cliffs of Kentucky,
+Tennessee, and North Carolina.
+
+
+
+
+                              SECTION IV
+
+            GRAIN, COLOR, ODOR, WEIGHT, AND FIGURE IN WOOD
+
+
+                       DIFFERENT GRAINS OF WOOD
+
+The terms "fine-grained," "coarse-grained," "straight-grained," and
+"cross-grained" are frequently applied in the trade. In common usage,
+wood is coarse-grained if its annual rings are wide; fine-grained if
+they are narrow. In the finer wood industries a fine-grained wood is
+capable of high polish, while a coarse-grained wood is not, so that in
+this latter case the distinction depends chiefly on hardness, and in
+the former on an accidental case of slow or rapid growth. Generally if
+the direction of the wood fibres is parallel to the axis of the stem
+or limb in which they occur, the wood is straight-grained; but in many
+cases the course of the fibres is spiral or twisted around the tree
+(as shown in Fig. 15), and sometimes commonly in the butts of gum and
+cypress, the fibres of several layers are oblique in one direction,
+and those of the next series of layers are oblique in the opposite
+direction. (As shown in Fig. 16 the wood is cross or twisted grain.)
+Wavy-grain in a tangential plane as seen on the radial section is
+illustrated in Fig. 17, which represents an extreme case observed in
+beech. This same form also occurs on the radial plane, causing the
+tangential section to appear wavy or in transverse folds.
+
+When wavy grain is fine (_i.e._, the folds or ridges small but
+numerous) it gives rise to the "curly" structure frequently seen in
+maple. Ordinarily, neither wavy, spiral, nor alternate grain is
+visible on the cross-section; its existence often escapes the eye even
+on smooth, longitudinal faces in the sawed material, so that the only
+guide to their discovery lies in splitting the wood in two, in the two
+normal plains.
+
+    [Illustration: Fig. 15. Spiral Grain. Season checks, after
+    removal of bark, indicate the direction of the fibres or
+    grain of the wood.]
+
+    [Illustration: Fig. 16. Alternating Spiral Grain in Cypress.
+    Side and end view of same piece. When the bark was at _o_,
+    the grain of this piece was straight. From that time, each
+    year it grew more oblique in one direction, reaching a climax
+    at _a_, and then turned back in the opposite direction. These
+    alternations were repeated periodically, the bark sharing in
+    these changes.]
+
+Generally the surface of the wood under the bark, and therefore also
+that of any layer in the interior, is not uniform and smooth, but is
+channelled and pitted by numerous depressions, which differ greatly in
+size and form. Usually, any one depression or elevation is restricted
+to one or few annual layers (_i.e._, seen only in one or few rings)
+and is then lost, being compensated (the surface at the particular
+spot evened up) by growth. In some woods, however, any depression or
+elevation once attained grows from year to year and reaches a maximum
+size, which is maintained for many years, sometimes throughout life.
+In maple, where this tendency to preserve any particular contour is
+very great, the depressions and elevations are usually small
+(commonly less than one-eighth inch) but very numerous.
+
+On tangent boards of such wood, the sections, pits, and prominences
+appear as circlets, and give rise to the beautiful "bird's eye" or
+"landscape" structure. Similiar structures in the burls of black ash,
+maple, etc., are frequently due to the presence of dormant buds, which
+cause the surface of all the layers through which they pass to be
+covered by small conical elevations, whose cross-sections on the sawed
+board appear as irregular circlets or islets, each with a dark speck,
+the section of the pith or "trace" of the dormant bud in the center.
+
+    [Illustration: Fig. 17. Wavy Grain in Beech (_after
+    Nordlinger_).]
+
+In the wood of many broad-leaved trees the wood fibres are much longer
+when full grown than when they are first formed in the cambium or
+growing zone. This causes the tips of each fibre to crowd in between
+the fibres above and below, and leads to an irregular interlacement of
+these fibres, which adds to the toughness, but reduces the
+cleavability of the wood. At the juncture of the limb and stem the
+fibres on the upper and lower sides of the limb behave differently.
+On the lower side they run from the stem into the limb, forming an
+uninterrupted strand or tissue and a perfect union. On the upper side
+the fibres bend aside, are not continuous into the limb, and hence the
+connection is not perfect (see Fig. 18). Owing to this arrangement of
+the fibres, the cleft made in splitting never runs into the knot if
+started on the side above the limb, but is apt to enter the knot if
+started below, a fact well understood in woodcraft. When limbs die,
+decay, and break off, the remaining stubs are surrounded, and may
+finally be covered by the growth of the trunk and thus give rise to
+the annoying "dead" or "loose" knots.
+
+    [Illustration: Fig. 18. Section of Wood showing Position of
+    the Grain at Base of a Limb. P, pith of both stem and limb;
+    1-7, seven yearly layers of wood; _a_, _b_, knot or basal
+    part of a limb which lived for four years, then died and
+    broke off near the stem, leaving the part to the left of _a_,
+    _b_, a "sound" knot, the part to the right a "dead" knot,
+    which would soon be entirely covered by the growing stem.]
+
+
+                        COLOR AND ODOR OF WOOD
+
+Color, like structure, lends beauty to the wood, aids in its
+identification, and is of great value in the determination of its
+quality. If we consider only the heartwood, the black color of the
+persimmon, the dark brown of the walnut, the light brown of the white
+oaks, the reddish brown of the red oaks, the yellowish white of the
+tulip and poplars, the brownish red of the redwood and cedars, the
+yellow of the papaw and sumac, are all reliable marks of distinction
+and color. Together with luster and weight, they are only too often
+the only features depended upon in practice. Newly formed wood, like
+that of the outer few rings, has but little color. The sapwood
+generally is light, and the wood of trees which form no heartwood
+changes but little, except when stained by forerunners of disease.
+
+The different tints of colors, whether the brown of oak, the orange
+brown of pine, the blackish tint of walnut, or the reddish cast of
+cedar, are due to pigments, while the deeper shade of the summer-wood
+bands in pine, cedar, oak, or walnut is due to the fact that the wood
+being denser, more of the colored wood substance occurs on a given
+space, _i.e._, there is more colored matter per square inch. Wood is
+translucent, a thin disk of pine permitting light to pass through
+quite freely. This translucency affects the luster and brightness of
+lumber.
+
+When lumber is attacked by fungi, it becomes more opaque, loses its
+brightness, and in practice is designated "dead," in distinction to
+"live" or bright timber. Exposure to air darkens all wood; direct
+sunlight and occasional moistening hasten this change, and cause it to
+penetrate deeper. Prolonged immersion has the same effect, pine wood
+becoming a dark gray, while oak changes to a blackish brown.
+
+Odor, like color, depends on chemical compounds, forming no part of
+the wood substance itself. Exposure to weather reduces and often
+changes the odor, but a piece of long-leaf pine, cedar, or camphor
+wood exhales apparently as much odor as ever when a new surface is
+exposed. Heartwood is more odoriferous than sapwood. Many kinds of
+wood are distinguished by strong and peculiar odors. This is
+especially the case with camphor, cedar, pine, oak, and mahogany, and
+the list would comprise every kind of wood in use were our sense of
+smell developed in keeping with its importance.
+
+Decomposition is usually accompanied by pronounced odors. Decaying
+poplar emits a disagreeable odor, while red oak often becomes
+fragrant, its smell resembling that of heliotrope.
+
+
+                            WEIGHT OF WOOD
+
+A small cross-section of wood (as in Fig. 19) dropped into water
+sinks, showing that the substance of which wood fibre or wood is built
+up is heavier than water. By immersing the wood successively in
+heavier liquids, until we find a liquid in which it does not sink, and
+comparing the weight of the same with water, we find that wood
+substance is about 1.6 times as heavy as water, and that this is as
+true of poplar as of oak or pine.
+
+    [Illustration: Fig. 19. Cross-section of a Group of Wood
+    Fibres (Highly Magnified.)]
+
+Separating a single cell (as shown in Fig. 20, _a_), drying and then
+dropping it into water, it floats. The air-filled cell cavity or
+interior reduces its weight, and, like an empty corked bottle, it
+weighs less than the water. Soon, however, water soaks into the cell,
+when it fills up and sinks. Many such cells grown together, as in a
+block of wood, when all or most of them are filled with water, will
+float as long as the majority of them are empty or only partially
+filled. This is why a green, sappy pine pole soon sinks in "driving"
+(floating down stream). Its cells are largely filled before it is
+thrown in, and but little additional water suffices to make its weight
+greater than that of the water. In a good-sized white pine log,
+composed chiefly of empty cells (heartwood), the water requires a very
+long time to fill up the cells (five years would not suffice to fill
+them all), and therefore the log may float for many months. When the
+wall of the wood fibre is very thick (five eighths or more of the
+volume, as in Fig. 20, _b_), the fibre sinks whether empty or filled.
+This applies to most of the fibres of the dark summer-wood bands in
+pines, and to the compact fibres of oak or hickory, and many,
+especially tropical woods, have such thick-walled cells and so little
+empty or air space that they never float.
+
+    [Illustration: Fig. 20. Isolated Fibres of Wood.]
+
+Here, then, are the two main factors of weight in wood; the amount of
+cell wall or wood substance constant for any given piece, and the
+amount of water contained in the wood, variable even in the standing
+tree, and only in part eliminated in drying.
+
+The weight of the green wood of any species varies chiefly as a second
+factor, and is entirely misleading, if the relative weight of
+different kinds is sought. Thus some green sticks of the otherwise
+lighter cypress and gum sink more readily than fresh oak.
+
+The weight of sapwood or the sappy, peripheral part of our common
+lumber woods is always great, whether cut in winter or summer. It
+rarely falls much below forty-five pounds, and commonly exceeds
+fifty-five pounds to the cubic foot, even in our lighter wooded
+species. It follows that the green wood of a sapling is heavier than
+that of an old tree, the fresh wood from a disk of the upper part of a
+tree is often heavier than that of the lower part, and the wood near
+the bark heavier than that nearer the pith; and also that the
+advantage of drying the wood before shipping is most important in
+sappy and light kinds.
+
+When kiln-dried, the misleading moisture factor of weight is uniformly
+reduced, and a fair comparison possible. For the sake of convenience
+in comparison, the weight of wood is expressed either as the weight
+per cubic foot, or, what is still more convenient, as specific weight
+or density. If an old long-leaf pine is cut up (as shown in Fig. 21)
+the wood of disk No. 1 is heavier than that of disk No. 2, the latter
+heavier than that of disk No. 3, and the wood of the top disk is found
+to be only about three fourths as heavy as that of disk No. 1.
+Similiarly, if disk No. 2 is cut up, as in the figure, the specific
+weight of the different parts is:
+
+              _a_, about 0.52
+              _b_, about 0.64
+              _c_, about 0.67
+    _d_, _e_, _f_, about 0.65
+
+showing that in this disk at least the wood formed during the many
+years' growth, represented in piece _a_, is much lighter than that of
+former years. It also shows that the best wood is the middle part,
+with its large proportion of dark summer bands.
+
+    [Illustration: Fig. 21. Orientation of Wood Samples.]
+
+Cutting up all disks in the same way, it will be found that the piece
+_a_ of the first disk is heavier than the piece _a_ of the fifth, and
+that piece _c_ of the first disk excels the piece _c_ of all the other
+disks. This shows that the wood grown during the same number of years
+is lighter in the upper parts of the stem; and if the disks are
+smoothed on the radial surfaces and set up one on top of the other in
+their regular order, for the sake of comparison, this decrease in
+weight will be seen to be accompanied by a decrease in the amount of
+summer-wood. The color effect of the upper disks is conspicuously
+lighter. If our old pine had been cut one hundred and fifty years ago,
+before the outer, lighter wood was laid on, it is evident that the
+weight of the wood of any one disk would have been found to increase
+from the center outward, and no subsequent decrease could have been
+observed.
+
+In a thrifty young pine, then, the wood is heavier from the center
+outward, and lighter from below upward; only the wood laid on in old
+age falls in weight below the average. The number of brownish bands of
+summer-wood are a direct indication of these differences. If an old
+oak is cut up in the same manner, the butt cut is also found heaviest
+and the top lightest, but, unlike the disk of pine, the disk of oak
+has its firmest wood at the center, and each successive piece from the
+center outward is lighter than its neighbor.
+
+Examining the pieces, this difference is not as readily explained by
+the appearance of each piece as in the case of pine wood.
+Nevertheless, one conspicuous point appears at once. The pores, so
+very distinct in oak, are very minute in the wood near the center, and
+thus the wood is far less porous.
+
+Studying different trees, it is found that in the pines, wood with
+narrow rings is just as heavy as and often heavier than the wood with
+wider rings; but if the rings are unusually narrow in any part of the
+disk, the wood has a lighter color; that is, there is less summer-wood
+and therefore less weight.
+
+In oak, ash, or elm trees of thrifty growth, the rings, fairly wide
+(not less than one-twelfth inch), always form the heaviest wood, while
+any piece with very narrow rings is light. On the other hand, the
+weight of a piece of hard maple or birch is quite independent of the
+width of its rings.
+
+The bases of limbs (knots) are usually heavy, very heavy in conifers,
+and also the wood which surrounds them, but generally the wood of the
+limbs is lighter than that of the stem, and the wood of the roots is
+the lightest.
+
+In general, it may be said that none of the native woods in common use
+in this country are when dry as heavy as water, _i.e._, sixty-two
+pounds to the cubic foot. Few exceed fifty pounds, while most of them
+fall below forty pounds, and much of the pine and other coniferous
+wood weigh less than thirty pounds per cubic foot. The weight of the
+wood is in itself an important quality. Weight assists in
+distinguishing maple from poplar. Lightness coupled with great
+strength and stiffness recommends wood for a thousand different uses.
+To a large extent weight predicates the strength of the wood, at least
+in the same species, so that a heavy piece of oak will exceed in
+strength a light piece of the same species, and in pine it appears
+probable that, weight for weight, the strength of the wood of various
+pines is nearly equal.
+
+WEIGHT OF KILN-DRIED WOOD OF DIFFERENT SPECIES
+-----------------------------------------+----------------------------
+                                         |        Approximate
+                                         |----------+-----------------
+                                         |          |    Weight of
+                                         |          |---------+-------
+           Species                       | Specific |    1    | 1,000
+                                         |  Weight  |  Cubic  |  Feet
+                                         |          |  Foot   | Lumber
+-----------------------------------------+----------+---------+-------
+(_a_) Very Heavy Woods:                  |          |         |
+  Hickory, Oak, Persimmon, Osage Orange, |          |         |
+  Black Locust, Hackberry, Blue Beech,   |          |         |
+  best of Elm and Ash                    |0.70-0.80 |  42-48  | 3,700
+(_b_) Heavy Woods                        |          |         |
+  Ash, Elm, Cherry, Birch, Maple, Beech, |          |         |
+  Walnut, Sour Gum, Coffee Tree, Honey   |          |         |
+  Locust, best of Southern Pine and      |          |         |
+  Tamarack                               |0.60-0.70 |  36-42  | 3,200
+(_c_) Woods of Medium Weight:            |          |         |
+  Southern Pine, Pitch Pine, Tamarack,   |          |         |
+  Douglas Spruce, Western Hemlock,       |          |         |
+  Sweet Gum, Soft Maple, Sycamore,       |          |         |
+  Sassafras, Mulberry, light grades of   |          |         |
+  Birch and Cherry                       |0.50-0.60 |  30-36  | 2,700
+(_d_) Light Woods:                       |          |         |
+  Norway and Bull Pine, Red Cedar,       |          |         |
+  Cypress, Hemlock, the Heavier Spruces  |          |         |
+  and Firs, Redwood, Basswood, Chestnut, |          |         |
+  Butternut, Tulip, Catalpa, Buckeye,    |          |         |
+  heavier grades of Poplar               |0.40-0.50 |  24-30  | 2,200
+(_e_) Very Light Woods:                   |          |         |
+  White Pine, Spruce, Fir, White Cedar,  |          |         |
+  Poplar                                 |0.30-0.40 |  18-24  | 1,800
+-----------------------------------------+----------+---------+-------
+
+
+                           "FIGURE" IN WOOD
+
+Many theories have been propounded as to the cause of "figure" in
+timber; while it is true that all timber possesses "figure" in some
+degree, which is more noticeable if it be cut in certain ways, yet
+there are some woods in which it is more conspicuous than in others,
+and which for cabinet or furniture work are much appreciated, as it
+adds to the value of the work produced.
+
+The characteristic "figure" of oak is due to the broad and deep
+medullary rays so conspicuous in this timber, and the same applies to
+honeysuckle. Figure due to the same cause is found in sycamore and
+beech, but is not so pronounced. The beautiful figure in "bird's eye
+maple" is supposed to be due to the boring action of insects in the
+early growth of the tree, causing pits or grooves, which in time
+become filled up by being overlain by fresh layers of wood growth;
+these peculiar and unique markings are found only in the older and
+inner portion of the tree.
+
+Pitch pine has sometimes a very beautiful "figure," but it generally
+does not go deep into the timber; walnut has quite a variety of
+"figures," and so has the elm. It is in mahogany, however, that we
+find the greatest variety of "figure," and as this timber is only used
+for furniture and fancy work, a good "figure" greatly enhances its
+value, as firmly figured logs bring fancy prices.
+
+Mahogany, unlike the oak, never draws its "figure" from its small and
+almost unnoticeable medullary rays, but from the twisted condition of
+its fibres; the natural growth of mahogany produces a straight wood;
+what is called "figured" is unnatural and exceptional, and thus adds
+to its value as an ornamental wood. These peculiarities are rarely
+found in the earlier portion of the tree that is near the center,
+being in this respect quite different from maple; they appear when the
+tree is more fully developed, and consist of bundles of woody fibres
+which, instead of being laid in straight lines, behave in an erratic
+manner and are deposited in a twisted form; sometimes it may be caused
+by the intersection of branches, or possibly by the crackling of the
+bark pressing on the wood, and thus moving it out of its natural
+straight course, causing a wavy line which in time becomes
+accentuated.
+
+It will have been observed by most people that the outer portion of a
+tree is often indented by the bark, and the outer rings often follow a
+sinuous course which corresponds to this indention, but in most trees,
+after a few years, this is evened up and the annual rings assume their
+nearly circular form; it is supposed by some that in the case of
+mahogany this is not the case, and that the indentations are even
+accentuated.
+
+The best figured logs of timber are secured from trees which grow in
+firm rocky soil; those growing on low-lying or swampy ground are
+seldom figured. To the practical woodworker the figure in mahogany
+causes some difficulty in planing the wood to a smooth surface; some
+portions plane smooth, others are the "wrong way of the grain."
+
+Figure in wood is effected by the way light is thrown upon it, showing
+light if seen from one direction, and dark if viewed from another, as
+may easily be observed by holding a piece of figured mahogany under
+artificial light and looking at it from opposite directions. The
+characteristic markings on mahogany are "mottle," which is also found
+in sycamore, and is conspicuous on the backs of fiddles and violins,
+and is not in itself valuable; it runs the transverse way of the
+fibres and is probably the effect of the wind upon the tree in its
+early stages of growth. "Roe," which is said to be caused by the
+contortion of the woody fibres, and takes a wavy line parallel to
+them, is also found in the hollow of bent stems and in the root
+structure, and when combined with "mottle" is very valuable. "Dapple"
+is an exaggerated form of mottle. "Thunder shake," "wind shake," or
+"tornado shake" is a rupture of the fibres across the grain, which in
+mahogany does not always break them; the tree swaying in the wind only
+strains its fibres, and thus produces mottle in the wood.
+
+
+
+
+                               SECTION V
+
+                            ENEMIES OF WOOD
+
+
+From the writer's personal investigations of this subject in different
+sections of the country, the damage to forest products of various
+kinds from this cause seems to be far more extensive than is generally
+recognized. Allowing a loss of five per cent on the total value of the
+forest products of the country, which the writer believes to be a
+conservative estimate, it would amount to something over $30,000,000
+annually. This loss differs from that resulting from insect damage to
+natural forest resources, in that it represents more directly a loss
+of money invested in material and labor. In dealing with the insects
+mentioned, as with forest insects in general, the methods which yield
+the best results are those which relate directly to preventing attack,
+as well as those which are unattractive or unfavorable. The insects
+have two objects in their attack: one is to obtain food, the other is
+to prepare for the development of their broods. Different species of
+insects have special periods during the season of activity (March to
+November), when the adults are on the wing in search of suitable
+material in which to deposit their eggs. Some species, which fly in
+April, will be attracted to the trunks of recently felled pine trees
+or to piles of pine sawlogs from trees felled the previous winter.
+They are not attracted to any other kind of timber, because they can
+live only in the bark or wood of pine, and only in that which is in
+the proper condition to favor the hatching of their eggs and the
+normal development of their young. As they fly only in April, they
+cannot injure the logs of trees felled during the remainder of the
+year.
+
+There are also oak insects, which attack nothing but oak; hickory,
+cypress, and spruce insects, etc., which have different habits and
+different periods of flight, and require special conditions of the
+bark and wood for depositing their eggs or for subsequent development
+of their broods. Some of these insects have but one generation in a
+year, others have two or more, while some require more than one year
+for the complete development and transformation. Some species deposit
+their eggs in the bark or wood of trees soon after they are felled or
+before any perceptible change from the normal living tissue has taken
+place; other species are attracted only to dead bark and dead wood of
+trees which have been felled or girdled for several months; others are
+attracted to dry and seasoned wood; while another class will attack
+nothing but very old, dry bark or wood of special kinds and under
+special conditions. Thus it will be seen how important it is for the
+practical man to have knowledge of such of the foregoing facts as
+apply to his immediate interest in the manufacture or utilization of a
+given forest product, in order that he may with the least trouble and
+expense adjust his business methods to meet the requirements for
+preventing losses.
+
+The work of different kinds of insects, as represented by special
+injuries to forest products, is the first thing to attract attention,
+and the distinctive character of this work is easily observed, while
+the insect responsible for it is seldom seen, or it is so difficult to
+determine by the general observer from descriptions or illustrations
+that the species is rarely recognized. Fortunately, the character of
+the work is often sufficient in itself to identify the cause and
+suggest a remedy, and in this section primary consideration is given
+to this phase of the subject.
+
+
+                      Ambrosia or Timber Beetles
+
+    [Illustration: Fig. 22. Work of Ambrosia Beetles in Tulip or
+    Yellow Poplar Wood. _a_, work of _Xyleborus affinis_ and
+    _Xyleborus inermis_; _b_, _Xyleborus obesus_ and work; _c_,
+    bark; _d_, sapwood; _e_, heartwood.]
+
+    [Illustration: Fig. 23. Work of Ambrosia Beetles in Oak. _a_,
+    _Monarthrum mali_ and work; _b_, _Platypus compositus_ and
+    work; _c_, bark; _d_, sapwood; _e_, heartwood; _f_, character
+    of work in wood from injured log.]
+
+The characteristic work of this class of wood-boring beetles is shown
+in Figs. 22 and 23. The injury consists of pinhole and stained-wood
+defects in the sapwood and heartwood of recently felled or girdled
+trees, sawlogs, pulpwood, stave and shingle bolts, green or
+unseasoned lumber, and staves and heads of barrels containing
+alcoholic liquids. The holes and galleries are made by the adult
+parent beetles, to serve as entrances and temporary houses or
+nurseries for the development of their broods of young, which feed on
+a fungus growing on the walls of the galleries.
+
+The growth of this ambrosia-like fungus is induced and controlled by
+the parent beetles, and the young are dependent upon it for food. The
+wood must be in exactly the proper condition for the growth of the
+fungus in order to attract the beetles and induce them to excavate
+their galleries; it must have a certain degree of moisture and other
+favorable qualities, which usually prevail during the period involved
+in the change from living, or normal, to dead or dry wood; such a
+condition is found in recently felled trees, sawlogs, or like crude
+products.
+
+There are two general types or classes of these galleries: one in
+which the broods develop together in the main burrows (see Fig. 22),
+the other in which the individuals develop in short, separate side
+chambers, extending at right angles from the primary galleries (see
+Fig. 23). The galleries of the latter type are usually accompanied by
+a distinct staining of the wood, while those of the former are not.
+
+The beetles responsible for this work are cylindrical in form,
+apparently with a head (the prothorax) half as long as the remainder
+of the body (see Figs. 22, _a_, and 23, _a_).
+
+North American species vary in size from less than one-tenth to
+slightly more than two-tenths of an inch, while some of the
+subtropical and tropical species attain a much larger size. The
+diameter of the holes made by each species corresponds closely to that
+of the body, and varies from about one-twentieth to one-sixteenth of
+an inch for the tropical species.
+
+
+                          Round-headed Borers
+
+    [Illustration: Fig. 24. Work of Round-headed and Flat-headed
+    Borers in Pine. _a_, work of round-headed borer, "sawyer,"
+    _Monohammus spiculatus_, natural size _b_, _Ergates
+    spiculatus_; _c_, work of flat-headed borer, _Buprestis_,
+    larva and adult; _d_, bark; _e_, sapwood; _f_, heartwood.]
+
+The character of the work of this class of wood- and bark-boring grubs
+is shown in Fig. 24. The injuries consist of irregular flattened or
+nearly round wormhole defects in the wood, which sometimes result in
+the destruction of valuable parts of the wood or bark material. The
+sapwood and heartwood of recently felled trees, sawlogs, poles posts,
+mine props, pulpwood and cordwood, also lumber or square timber, with
+bark on the edges, and construction timber in new and old buildings,
+are injured by wormhole defects, while the valuable parts of stored
+oak and hemlock tanbark and certain kinds of wood are converted into
+worm-dust. These injuries are caused by the young or larvae of
+long-horned beetles. Those which infest the wood hatch from eggs
+deposited in the outer bark of logs and like material, and the minute
+grubs hatching therefrom bore into the inner bark, through which they
+extend their irregular burrows, for the purpose of obtaining food from
+the sap and other nutritive material found in the plant tissue. They
+continue to extend and enlarge their burrows as they increase in size,
+until they are nearly or quite full grown. They then enter the wood
+and continue their excavations deep into the sapwood or heartwood
+until they attain their normal size. They then excavate pupa cells in
+which to transform into adults, which emerge from the wood through
+exit holes in the surface. This class of borers is represented by a
+large number of species. The adults, however, are seldom seen by the
+general observer unless cut out of the wood before they have emerged.
+
+
+                          Flat-headed Borers
+
+The work of the flat-headed borers (Fig. 24) is only distinguished
+from that of the preceding by the broad, shallow burrows, and the much
+more oblong form of the exit holes. In general, the injuries are
+similiar, and effect the same class of products, but they are of much
+less importance. The adult forms are flattened, metallic-colored
+beetles, and represent many species, of various sizes.
+
+
+                             Timber Worms
+
+    [Illustration: Fig. 25. Work of Timber Worms in Oak. _a_,
+    work of oak timber worm, _Eupsalis minuta_; _b_, barked
+    surface; _c_, bark; _d_, sapwood timber worm, _Hylocoetus
+    lugubris_, and work; _e_, sapwood.]
+
+The character of the work done by this class is shown in Fig. 25. The
+injury consists of pinhole defects in the sapwood and heartwood of
+felled trees, sawlogs and like material which have been left in the
+woods or in piles in the open for several months during the warmer
+seasons. Stave and shingle bolts and closely piled oak lumber and
+square timbers also suffer from injury of this kind. These injuries
+are made by elongate, slender worms or larvae, which hatch from eggs
+deposited by the adult beetles in the outer bark, or, where there is
+no bark, just beneath the surface of the wood. At first the young
+larvae bore almost invisible holes for a long distance through the
+sapwood and heartwood, but as they increase in size the same holes are
+enlarged and extended until the larvae have attained their full
+growth. They then transform to adults, and emerge through the enlarged
+entrance burrows. The work of these timber worms is distinguished from
+that of the timber beetles by the greater variation in the size of
+holes in the same piece of wood, also by the fact that they are not
+branched from a single entrance or gallery, as are those made by the
+beetles.
+
+    [Illustration: Fig. 26. Work of Powder Post Beetle,
+    _Sinoxylon basilare_, in Hickory Poles, showing Transverse
+    Egg Galleries excavated by the Adult, _a_, entrance; _b_,
+    gallery; _c_, adult.]
+
+    [Illustration: Fig. 27. Work of Powder
+    Post Beetle, _Sinoxylon basilare_, in Hickory Pole. _a_,
+    character of work by larvae; _b_, exit holes made by
+    emerging broods.]
+
+
+                          Powder Post Borers
+
+The character of the work of this class of insects is shown in Figs.
+26, 27, and 28. The injury consists of closely placed burrows, packed
+with borings, or a completely destroyed or powdered condition of the
+wood of seasoned products, such as lumber, crude and finished handle
+and wagon stock, cooperage and wooden truss hoops, furniture, and
+inside finish woodwork, in old buildings, as well as in many other
+crude or finished and utilized woods. This is the work of both the
+adults and young stages of some species, or of the larval stage alone
+of others. In the former, the adult beetles deposit their eggs in
+burrows or galleries excavated for the purpose, as in Figs. 26 and 27,
+while in the latter (Fig. 28) the eggs are on or beneath the surface
+of the wood. The grubs complete the destruction by boring through the
+solid wood in all directions and packing their burrows with the
+powdered wood. When they are full grown they transform to the adult,
+and emerge from the injured material through holes in the surface.
+Some of the species continue to work in the same wood until many
+generations have developed and emerged or until every particle of wood
+tissue has been destroyed and the available nutritive substance
+extracted.
+
+    [Illustration: Fig. 28. Work of Powder Post Beetles, _Lyctus
+    striatus_, in Hickory Handles and Spokes. _a_, larva; _b_,
+    pupa; _c_, adult; _d_, exit holes; _e_, entrance of larvae
+    (vents for borings are exits of parasites); _f_, work of
+    larvae; _g_, wood, completely destroyed; _h_, sapwood; _i_,
+    heartwood.]
+
+
+                    Conditions Favorable for Insect
+           Injury--Crude Products--Round Timber with Bark on
+
+Newly felled trees, sawlogs, stave and heading bolts, telegraph poles,
+posts, and the like material, cut in the fall and winter, and left on
+the ground or in close piles during a few weeks or months in the
+spring or summer, causing them to heat and sweat, are especially
+liable to injury by ambrosia beetles (Figs. 22 and 23), round and
+flat-headed borers (Fig. 24), and timber worms (Fig. 25), as are also
+trees felled in the warm season, and left for a time before working up
+into lumber.
+
+The proper degree of moisture found in freshly cut living or dying
+wood, and the period when the insects are flying, are the conditions
+most favorable for attack. This period of danger varies with the time
+of the year the timber is felled and with the different kinds of
+trees. Those felled in late fall and winter will generally remain
+attractive to ambrosia beetles, and to the adults of round- and
+flat-headed borers during March, April, and May. Those felled in April
+to September may be attacked in a few days after they are felled, and
+the period of danger may not extend over more than a few weeks.
+Certain kinds of trees felled during certain months and seasons are
+never attacked, because the danger period prevails only when the
+insects are flying; on the other hand, if the same kinds of trees are
+felled at a different time, the conditions may be most attractive when
+the insects are active, and they will be thickly infested and ruined.
+
+The presence of bark is absolutely necessary for infestation by most
+of the wood-boring grubs, since the eggs and young stages must occupy
+the outer and inner portions before they can enter the wood. Some
+ambrosia and timber worms will, however, attack barked logs,
+especially those in close piles, and others shaded and protected from
+rapid drying.
+
+The sapwood of pine, spruce, fir, cedar, cypress, and the like
+softwoods is especially liable to injury by ambrosia beetles, while
+the heartwood is sometimes ruined by a class of round-headed borers,
+known as "sawyers." Yellow poplar, oak, chestnut, gum, hickory, and
+most other hardwoods are as a rule attacked by species of ambrosia
+beetles, sawyers, and timber worms, different from those infesting the
+pines, there being but very few species which attack both.
+
+Mahogany and other rare and valuable woods imported from the tropics
+to this country in the form of round logs, with or without bark on,
+are commonly damaged more or less seriously by ambrosia beetles and
+timber worms.
+
+It would appear from the writer's investigations of logs received at
+the mills in this country, that the principal damage is done during a
+limited period--from the time the trees are felled until they are
+placed in fresh or salt water for transportation to the shipping
+points. If, however, the logs are loaded on a vessel direct from the
+shore, or if not left in the water long enough to kill the insects,
+the latter will continue their destructive work during transportation
+to other countries and after they arrive, and until cold weather
+ensues or the logs are converted into lumber.
+
+It was also found that a thorough soaking in sea-water, while it
+usually killed the insects at the time, did not prevent subsequent
+attacks by both foreign and native ambrosia beetles; also, that the
+removal of the bark from such logs previous to immersion did not
+render them entirely immune. Those with the bark off were attacked
+more than those with it on, owing to a greater amount of saline
+moisture retained by the bark.
+
+
+                         How to Prevent Injury
+
+From the foregoing it will be seen that some requisites for preventing
+these insect injuries to round timber are:
+
+     1. To provide for as little delay as possible between the
+     felling of the tree and its manufacture into rough products.
+     This is especially necessary with trees felled from April to
+     September, in the region north of the Gulf States, and from
+     March to November in the latter, while the late fall and
+     winter cutting should all be worked up by March or April.
+
+     2. If the round timber must be left in the woods or on the
+     skidways during the danger period, every precaution should
+     be taken to facilitate rapid drying of the inner bark, by
+     keeping the logs off the ground in the sun, or in loose
+     piles; or else the opposite extreme should be adopted and
+     the logs kept in water.
+
+     3. The immediate removal of all the bark from poles, posts,
+     and other material which will not be seriously damaged by
+     checking or season checks.
+
+     4. To determine and utilize the proper months or seasons to
+     girdle or fell different kinds of trees: Bald cypress in the
+     swamps of the South are "girdled" in order that they may
+     die, and in a few weeks or months dry out and become light
+     enough to float. This method has been extensively adopted in
+     sections where it is the only practicable one by which the
+     timber can be transported to the sawmills. It is found,
+     however, that some of these "girdled" trees are especially
+     attractive to several species of ambrosia beetles (Figs. 22
+     and 23), round-headed borers (Fig. 24) and timber worms
+     (Fig. 25), which cause serious injury to the sapwood or
+     heartwood, while other trees "girdled" at a different time
+     or season are not injured. This suggested to the writer the
+     importance of experiments to determine the proper time to
+     "girdle" trees to avoid losses, and they are now being
+     conducted on an extensive scale by the United States Forest
+     Service, in co-operation with prominent cypress operators in
+     different sections of the cypress-growing region.
+
+
+                               Saplings
+
+Saplings, including hickory and other round hoop-poles and similiar
+products, are subject to serious injuries and destruction by round-
+and flat-headed borers (Fig. 24), and certain species of powder post
+borers (Figs. 26 and 27) before the bark and wood are dead or dry, and
+also by other powder post borers (Fig. 28) after they are dried and
+seasoned. The conditions favoring attack by the former class are those
+resulting from leaving the poles in piles or bundles in or near the
+forest for a few weeks during the season of insect activity, and by
+the latter from leaving them stored in one place for several months.
+
+
+                   Stave, Heading and Shingle Bolts
+
+These are attacked by ambrosia beetles (Figs. 22 and 23), and the oak
+timber worm (Fig. 25, _a_), which, as has been frequently reported,
+cause serious losses. The conditions favoring attack by these insects
+are similiar to those mentioned under "Round Timber." The insects may
+enter the wood before the bolts are cut from the log or afterward,
+especially if the bolts are left in moist, shady places in the woods,
+in close piles during the danger period. If cut during the warm
+season, the bark should be removed and the bolts converted into the
+smallest practicable size and piled in such manner as to facilitate
+rapid drying.
+
+
+                   Unseasoned Products in the Rough
+
+Freshly sawn hardwood, placed in close piles during warm, damp weather
+in July and September, presents especially favorable conditions for
+injury by ambrosia beetles (Figs. 22, _a_, and 23, _a_). This is due
+to the continued moist condition of such material.
+
+Heavy two-inch or three-inch stuff is also liable to attack even in
+loose piles with lumber or cross sticks. An example of the latter was
+found in a valuable lot of mahogany lumber of first grade, the value
+of which was reduced two thirds by injury from a native ambrosia
+beetle. Numerous complaints have been received from different sections
+of the country of this class of injury to oak, poplar, gum, and other
+hardwoods. In all cases it is the moist condition and retarded drying
+of the lumber which induces attack; therefore, any method which will
+provide for the rapid drying of the wood before or after piling will
+tend to prevent losses.
+
+It is important that heavy lumber should, as far as possible, be cut
+in the winter months and piled so that it will be well dried out
+before the middle of March. Square timber, stave and heading bolts,
+with the bark on, often suffer from injuries by flat- or round-headed
+borers, hatching from eggs deposited in the bark of the logs before
+they are sawed and piled. One example of serious damage and loss was
+reported in which white pine staves for paint buckets and other small
+wooden vessels, which had been sawed from small logs, and the bark
+left on the edges, were attacked by a round-headed borer, the adults
+having deposited their eggs in the bark after the stock was sawn and
+piled. The character of the injury is shown in Fig. 29. Another
+example was reported from a manufacturer in the South, where the
+pieces of lumber which had strips of bark on one side were seriously
+damaged by the same kind of borer, the eggs having been deposited in
+the logs before sawing or in the bark after the lumber was piled. If
+the eggs are deposited in the logs, and the borers have entered the
+inner bark or the wood before sawing, they may continue their work
+regardless of methods of piling, but if such lumber is cut from new
+logs and placed in the pile while green, with the bark surface up, it
+will be much less liable to attack than if piled with the bark edges
+down. This liability of lumber with bark edges or sides to be attacked
+by insects suggests the importance of the removal of the bark, to
+prevent damage, or, if this is not practicable, the lumber with the
+bark on the sides should be piled in open, loose piles with the bark
+up, while that with the bark on the edges should be placed on the
+outer edges of the piles, exposed to the light and air.
+
+    [Illustration: Fig. 29. Work of Round-headed Borers,
+    _Callidium antennatum_, in White Pine Bucket Staves from New
+    Hampshire. _a_, where egg was deposited in bark; _b_, larval
+    mine; _c_, pupal cell; _d_, exit in bark; _e_, adult.]
+
+In the Southern States it is difficult to keep green timber in the
+woods or in piles for any length of time, because of the rapidity
+which wood-destroying fungi attack it. This is particularly true
+during the summer season, when the humidity is greatest. There is
+really no easily-applied, general specific for these summer troubles
+in the handling of wood, but there are some suggestions that are worth
+while that it may be well to mention. One of these, and the most
+important, is to remove all the bark from the timber that has been
+cut, just as soon as possible after felling. And, in this, emphasis
+should be laid on the ALL, as a piece of bark no larger than a man's
+little finger will furnish an entering place for insects, and once
+they get in, it is a difficult matter to get rid of them, for they
+seldom stop boring until they ruin the stick. And again, after the
+timber has been felled and the bark removed, it is well to get it to
+the mill pond or cut up into merchantable sizes and on to the pile as
+soon as possible. What is wanted is to get the timber up off the
+ground, to a place where it can get plenty of air, to enable the sap
+to dry up before it sours; and, besides, large units of wood are more
+likely to crack open on the ends from the heat than they would if cut
+up into the smaller units for merchandizing.
+
+A moist condition of lumber and square timber, such as results from
+close or solid piles, with the bottom layers on the ground or on
+foundations of old decaying logs or near decaying stumps and logs,
+offers especially favorable conditions for the attack of white ants.
+
+
+                    Seasoned Products in the Rough
+
+Seasoned or dry timber in stacks or storage is liable to injury by
+powder post borers (Fig. 28). The conditions favoring attack are: (1)
+The presence of a large proportion of sapwood, as in hickory, ash, and
+similiar woods; (2) material which is two or more years old, or that
+which has been kept in one place for a long time; (3) access to old
+infested material. Therefore, such stock should be frequently examined
+for evidence of the presence of these insects. This is always
+indicated by fine, flour-like powder on or beneath the piles, or
+otherwise associated with such material. All infested material should
+be at once removed and the infested parts destroyed by burning.
+
+
+              Dry Cooperage Stock and Wooden Truss Hoops
+
+These are especially liable to attack and serious injury by powder
+post borers (Fig. 28), under the same or similiar conditions as the
+preceding.
+
+
+       Staves and Heads of Barrels containing Alcoholic Liquids
+
+These are liable to attack by ambrosia beetles (Figs. 22, _a_, and 23,
+_a_), which are attracted by the moist condition and possibly by the
+peculiar odor of the wood, resembling that of dying sapwood of trees
+and logs, which is their normal breeding place.
+
+There are many examples on record of serious losses of liquors from
+leakage caused by the beetles boring through the staves and heads of
+the barrels and casks in cellars and storerooms.
+
+The condition, in addition to the moisture of the wood, which is
+favorable for the presence of the beetles, is proximity to their
+breeding places, such as the trunks and stumps of recently felled or
+dying oak, maple, and other hardwood or deciduous trees; lumber yards,
+sawmills, freshly-cut cordwood, from living or dead trees, and forests
+of hardwood timber. Under such conditions the beetles occur in great
+numbers, and if the storerooms and cellars in which the barrels are
+kept stored are damp, poorly ventilated, and readily accessible to
+them, serious injury is almost certain to follow.
+
+
+
+
+                              SECTION VI
+
+                             WATER IN WOOD
+
+                     DISTRIBUTION OF WATER IN WOOD
+
+
+                  Local Distribution of Water in Wood
+
+As seasoning means essentially the more or less rapid evaporation of
+water from wood, it will be necessary to discuss at the very outset
+where water is found in wood, and its local seasonal distribution in a
+tree.
+
+Water may occur in wood in three conditions: (1) It forms the greater
+part (over 90 per cent) of the protoplasmic contents of the living
+cells; (2) it saturates the walls of all cells; and (3) it entirely or
+at least partly fills the cavities of the lifeless cells, fibres, and
+vessels.
+
+In the sapwood of pine it occurs in all three forms; in the heartwood
+only in the second form, it merely saturates the walls.
+
+Of 100 pounds of water associated with 100 pounds of dry wood
+substance taken from 200 pounds of fresh sapwood of white pine, about
+35 pounds are needed to saturate the cell walls, less than 5 pounds
+are contained in the living cells, and the remaining 60 pounds partly
+fill the cavities of the wood fibres. This latter forms the sap as
+ordinarily understood.
+
+The wood next to the bark contains the most water. In the species
+which do not form heartwood, the decrease toward the pith is gradual,
+but where heartwood is formed the change from a more moist to a drier
+condition is usually quite abrupt at the sapwood limit.
+
+In long-leaf pine, the wood of the outer one inch of a disk may
+contain 50 per cent of water, that of the next, or the second inch,
+only 35 per cent, and that of the heartwood, only 20 per cent. In
+such a tree the amount of water in any one section varies with the
+amount of sapwood, and is greater for the upper than the lower cuts,
+greater for the limbs than the stems, and greatest of all in the
+roots.
+
+Different trees, even of the same kind and from the same place, differ
+as to the amount of water they contain. A thrifty tree contains more
+water than a stunted one, and a young tree more than on old one, while
+the wood of all trees varies in its moisture relations with the season
+of the year.
+
+
+                Seasonal Distribution of Water in Wood
+
+It is generally supposed that trees contain less water in winter than
+in summer. This is evidenced by the popular saying that "the sap is
+down in the winter." This is probably not always the case; some trees
+contain as much water in winter as in summer, if not more. Trees
+normally contain the greatest amount of water during that period when
+the roots are active and the leaves are not yet out. This activity
+commonly begins in January, February, and March, the exact time
+varying with the kind of timber and the local atmospheric conditions.
+And it has been found that green wood becomes lighter or contains less
+water in late spring or early summer, when transpiration through the
+foliage is most rapid. The amount of water at any one season, however,
+is doubtless much influenced by the amount of moisture in the soil.
+The fact that the bark peels easily in the spring depends on the
+presence of incomplete, soft tissue found between wood and bark during
+this season, and has little to do with the total amount of water
+contained in the wood of the stem.
+
+Even in the living tree a flow of sap from a cut occurs only in
+certain kinds of trees and under special circumstances. From boards,
+felled timber, etc., the water does not flow out, as is sometimes
+believed, but must be evaporated. The seeming exceptions to this rule
+are mostly referable to two causes; clefts or "shakes" will allow
+water contained in them to flow out, and water is forced out of sound
+wood, if very sappy, whenever the wood is warmed, just as water flows
+from green wood when put in a stove.
+
+
+                          Composition of Sap
+
+The term "sap" is an ambiguous expression. The sap in the tree
+descends through the bark, and except in early spring is not present
+in the wood of the tree except in the medullary rays and living
+tissues in the "sapwood."
+
+What flows through the "sapwood" is chiefly water brought from the
+soil. It is not pure water, but contains many substances in solution,
+such as mineral salts, and in certain species--maple, birch, etc., it
+also contains at certain times a small percentage of sugar and other
+organic matter.
+
+The water rises from the roots through the sapwood to the leaves,
+where it is converted into true "sap" which descends through the bark
+and feeds the living tissues between the bark and the wood, which
+tissues make the annual growth of the trunk. The wood itself contains
+very little true sap and the heartwood none.
+
+The wood contains, however, mineral substances, organic acids,
+volatile oils and gums, as resin, cedar oil, etc.
+
+All the conifers--pines, cedars, junipers, cypresses, sequoias, yews,
+and spruces--contain resin. The sap of deciduous trees--those which
+shed their leaves at stated seasons--is lacking in this element, and
+its constituents vary greatly in the different species. But there is
+one element common to all trees, and for that matter to almost all
+plant growth, and that is albumen.
+
+Both resin and albumen, as they exist in the sap of woods, are soluble
+in water; and both harden with heat, much the same as the white of an
+egg, which is almost pure albumen.
+
+These organic substances are the dissolved reserve food, stored during
+the winter in the pith rays, etc., of the wood and bark; generally but
+a mere trace of them is to be found. From this it appears that the
+solids contained in the sap, such as albumen, gum, sugar, etc.,
+cannot exercise the influence on the strength of the wood which is so
+commonly claimed for them.
+
+
+                      Effects of Moisture on Wood
+
+The question of the effect of moisture upon the strength and stiffness
+of wood offers a wide scope for study, and authorities consulted
+differ in conclusions. Two authorities give the tensile strength in
+pounds per square inch for white oak as 10,000 and 19,500,
+respectively; for spruce, 8,000 to 19,500, and other species in
+similiar startling contrasts.
+
+Wood, we are told, is composed of organic products. The chief material
+is cellulose, and this in its natural state in the living plant or
+green wood contains from 25 to 35 per cent of its weight in moisture.
+The moisture renders the cellulose substance pliable. What the
+physical action of the water is upon the molecular structure of
+organic material, to render it softer and more pliable, is largely a
+matter of conjecture.
+
+The strength of a timber depends not only upon its relative freedom
+from imperfections, such as knots, crookedness of grain, decay,
+wormholes or ring-shakes, but also upon its density; upon the rate at
+which it grew, and upon the arrangement of the various elements which
+compose it.
+
+The factors effecting the strength of wood are therefore of two
+classes: (1) Those inherent in the wood itself and which may cause
+differences to exist between two pieces from the same species of wood
+or even between the two ends of a piece, and (2) those which are
+foreign to the wood itself, such as moisture, oils, and heat.
+
+Though the effect of moisture is generally temporary, it is far more
+important than is generally realized. So great, indeed, is the effect
+of moisture that under some conditions it outweighs all the other
+causes which effect strength, with the exception, perhaps of decided
+imperfections in the wood itself.
+
+
+                  The Fibre Saturation Point in Wood
+
+Water exists in green wood in two forms: (1) As liquid water contained
+in the cavities of the cells or pores, and (2) as "imbibed" water
+intimately absorbed in the substance of which the wood is composed.
+The removal of the free water from the cells or pores will evidently
+have no effect upon the physical properties or shrinkage of the wood,
+but as soon as any of the "imbibed" moisture is removed from the cell
+walls, shrinkage begins to take place and other changes occur. The
+strength also begins to increase at this time.
+
+The point where the cell walls or wood substance becomes saturated is
+called the "fibre saturation point," and is a very significant point
+in the drying of wood.
+
+It is easy to remove the free water from woods which will stand a high
+temperature, as it is only necessary to heat the wood slightly above
+the boiling point in a closed vessel, which will allow the escape of
+the steam as it is formed, but will not allow dry air to come in
+contact with the wood, so that the surface will not become dried below
+its saturation point. This can be accomplished with most of the
+softwoods, but not as a rule with the hardwoods, as they are injured
+by the temperature necessary.
+
+The chief difficulties are encountered in evaporating the "imbibed"
+moisture and also where the free water has to be removed through its
+gradual transfusion instead of boiling. As soon as the imbibed
+moisture begins to be extracted from any portion, shrinkage takes
+place and stresses are set up in the wood which tend to cause
+checking.
+
+The fibre saturation point lies between moisture conditions of 25 and
+30 per cent of the dry weight of the wood, depending on the species.
+Certain species of eucalyptus, and probably other woods, however,
+appear to be exceptional in this respect, in that shrinkage begins to
+take place at a moisture condition of 80 to 90 per cent of the dry
+weight.
+
+
+
+
+                              SECTION VII
+
+                           WHAT SEASONING IS
+
+
+Seasoning is ordinarily understood to mean drying. When exposed to the
+sun and air, the water in green wood rapidly evaporates. The rate of
+evaporation will depend on: (1) the kind of wood; (2) the shape and
+thickness of the timber; and (3) the conditions under which the wood
+is placed or piled.
+
+Pieces of wood completely surrounded by air, exposed to the wind and
+the sun, and protected by a roof from rain and snow, will dry out very
+rapidly, while wood piled or packed close together so as to exclude
+the air, or left in the shade and exposed to rain and snow, will dry
+out very slowly and will also be subject to mould and decay.
+
+But seasoning implies other changes besides the evaporation of water.
+Although we have as yet only a vague conception as to the exact nature
+of the difference between seasoned and unseasoned wood, it is very
+probable that one of these consists in changes in the albuminous
+substances in the wood fibres, and possibly also in the tannins,
+resins, and other incrusting substances. Whether the change in these
+substances is merely a drying-out, or whether it consists in a partial
+decomposition is at yet undetermined. That the change during the
+seasoning process is a profound one there can be no doubt, because
+experience has shown again and again that seasoned wood fibre is very
+much more permeable, both for liquids and gases than the living,
+unseasoned fibre.
+
+One can picture the albuminous substances as forming a coating which
+dries out and possibly disintegrates when the wood dries. The
+drying-out may result in considerable shrinkage, which may make the
+wood fibre more porous. It is also possible that there are oxidizing
+influences at work within these substances which result in their
+disintegration. Whatever the exact nature of the change may be, one
+can say without hesitation that exposure to the wind and air brings
+about changes in the wood, which are of such a nature that the wood
+becomes drier and more permeable.
+
+When seasoned by exposure to live steam, similiar changes may take
+place; the water leaves the wood in the form of steam, while the
+organic compounds in the walls probably coagulate or disintegrate
+under the high temperature.
+
+The most effective seasoning is without doubt that obtained by the
+uniform, slow drying which takes place in properly constructed piles
+outdoors, under exposure to the winds and the sun and under cover from
+the rain and snow, and is what has been termed "air-seasoning." By
+air-seasoning oak and similiar hardwoods, nature performs certain
+functions that cannot be duplicated by any artificial means. Because
+of this, woods of this class cannot be successfully kiln-dried green
+from the saw.
+
+In drying wood, the free water within the cells passes through the
+cell walls until the cells are empty, while the cell walls remain
+saturated. When all the free water has been removed, the cell walls
+begin to yield up their moisture. Heat raises the absorptive power of
+the fibres and so aids the passage of water from the interior of the
+cells. A confusion in the word "sap" is to be found in many
+discussions of kiln-drying; in some instances it means water, in other
+cases it is applied to the organic substances held in a water solution
+in the cell cavities. The term is best confined to the organic
+substances from the living cell. These substances, for the most part
+of the nature of sugar, have a strong attraction for water and water
+vapor, and so retard drying and absorb moisture into dried wood. High
+temperatures, especially those produced by live steam, appear to
+destroy these organic compounds and therefore both to retard and to
+limit the reabsorption of moisture when the wood is subsequently
+exposed to the atmosphere.
+
+Air-dried wood, under ordinary atmospheric temperatures, retains from
+10 to 20 per cent of moisture, whereas kiln-dried wood may have no
+more than 5 per cent as it comes from the kiln. The exact figures for
+a given species depend in the first case upon the weather conditions,
+and in the second case upon the temperature in the kiln and the time
+during which the wood is exposed to it. When wood that has been
+kiln-dried is allowed to stand in the open, it apparently ceases to
+reabsorb moisture from the air before its moisture content equals that
+of wood which has merely been air-dried in the same place, and under
+the same conditions, in other words kiln-dried wood will not absorb as
+much moisture as air-dried wood under the same conditions.
+
+
+            Difference between Seasoned and Unseasoned Wood
+
+Although it has been known for a long time that there is a marked
+difference in the length of life of seasoned and of unseasoned wood,
+the consumers of wood have shown very little interest in its
+seasoning, except for the purpose of doing away with the evils which
+result from checking, warping, and shrinking. For this purpose both
+kiln-drying and air-seasoning are largely in use.
+
+The drying of material is a subject which is extremely important to
+most industries, and in no industry is it of more importance than in
+the lumber trade. Timber drying means not only the extracting of so
+much water, but goes very deeply into the quality of the wood, its
+workability and its cell strength, etc.
+
+Kiln-drying, which dries the wood at a uniformly rapid rate by
+artificially heating it in inclosed rooms, has become a part of almost
+every woodworking industry, as without it the construction of the
+finished product would often be impossible. Nevertheless much
+unseasoned or imperfectly seasoned wood is used, as is evidenced by
+the frequent shrinkage and warping of the finished articles. This is
+explained to a certain extent by the fact that the manufacturer is
+often so hard pressed for his product that he is forced to send out an
+inferior article, which the consumer is willing to accept in that
+condition rather than to wait several weeks or months for an article
+made up of thoroughly seasoned material, and also that dry kilns are
+at present constructed and operated largely without thoroughgoing
+system.
+
+Forms of kilns and mode of operation have commonly been copied by one
+woodworking plant after the example of some neighboring establishment.
+In this way it has been brought about that the present practices have
+many shortcomings. The most progressive operators, however, have
+experimented freely in the effort to secure special results desirable
+for their peculiar products. Despite the diversity of practice, it is
+possible to find among the larger and more enterprising operators a
+measure of agreement, as to both methods and results, and from this to
+outline the essentials of a correct theory. As a result, properly
+seasoned wood commands a high price, and in some cases cannot be
+obtained at all.
+
+Wood seasoned out of doors, which by many is supposed to be much
+superior to kiln-dried material, is becoming very scarce, as the
+demand for any kind of wood is so great that it is thought not to pay
+to hold it for the time necessary to season it properly. How long this
+state of affairs is going to last it is difficult to say, but it is
+believed that a reaction will come when the consumer learns that in
+the long run it does not pay to use poorly seasoned material. Such a
+condition has now arisen in connection with another phase of the
+seasoning of wood; it is a commonly accepted fact that dry wood will
+not decay nearly so fast as wet or green wood; nevertheless, the
+immense superiority of seasoned over unseasoned wood for all purposes
+where resistance to decay is necessary has not been sufficiently
+recognized. In the times when wood of all kinds was both plentiful and
+cheap, it mattered little in most cases how long it lasted or resisted
+decay. Wood used for furniture, flooring, car construction, cooperage,
+etc., usually got some chance to dry out before or after it was placed
+in use. The wood which was exposed to decaying influences was
+generally selected from those woods which, whatever their other
+qualities might be, would resist decay longest.
+
+To-day conditions have changed, so that wood can no longer be used to
+the same extent as in former years. Inferior woods with less lasting
+qualities have been pressed into service. Although haphazard methods
+of cutting and subsequent use are still much in vogue, there are many
+signs that both lumbermen and consumers are awakening to the fact that
+such carelessness and wasteful methods of handling wood will no longer
+do, and must give way to more exact and economical methods. The reason
+why many manufacturers and consumers of wood are still using the older
+methods is perhaps because of long custom, and because they have not
+yet learned that, though the saving to be obtained by the application
+of good methods has at all times been appreciable, now, when wood is
+more valuable, a much greater saving is possible. The increased cost
+of applying economical methods is really very slight, and is many
+times exceeded by the value of the increased service which can be
+secured through its use.
+
+
+                    Manner of Evaporation of Water
+
+The evaporation of water from wood takes place largely through the
+ends, _i.e._, in the direction of the longitudinal axis of the wood
+fibres. The evaporation from the other surfaces takes place very
+slowly out of doors, and with greater rapidity in a dry kiln. The rate
+of evaporation differs both with the kind of timber and its shape;
+that is, thin material will dry more rapidly than heavier stock.
+Sapwood dries faster than heartwood, and pine more rapidly than oak or
+other hardwoods.
+
+Tests made show little difference in the rate of evaporation in sawn
+and hewn stock, the results, however, not being conclusive. Air-drying
+out of doors takes from two months to a year, the time depending on
+the kind of timber, its thickness, and the climatic conditions. After
+wood has reached an air-dry condition it absorbs water in small
+quantities after a rain or during damp weather, much of which is
+immediately lost again when a few warm, dry days follow. In this way
+wood exposed to the weather will continue to absorb water and lose it
+for indefinite periods.
+
+When soaked in water, seasoned woods absorb water rapidly. This at
+first enters into the wood through the cell walls; when these are
+soaked, the water will fill the cell lumen, so that if constantly
+submerged the wood may become completely filled with water.
+
+The following figures show the gain in weight by absorption of several
+coniferous woods, air-dry at the start, expressed in per cent of the
+kiln-dry weight:
+
+                    ABSORPTION OF WATER BY DRY WOOD
+---------------------------------------------------------------
+                  | White Pine | Red Cedar | Hemlock | Tamarack
+---------------------------------------------------------------
+Air-dried         |    108     |   109     |   111   |   108
+Kiln-dried        |    100     |   100     |   100   |   100
+In water 1 day    |    135     |   120     |   133   |   129
+In water 2 days   |    147     |   126     |   144   |   136
+In water 3 days   |    154     |   132     |   149   |   142
+In water 4 days   |    162     |   137     |   154   |   147
+In water 5 days   |    165     |   140     |   158   |   150
+In water 7 days   |    176     |   143     |   164   |   156
+In water 9 days   |    179     |   147     |   168   |   157
+In water 11 days  |    184     |   149     |   173   |   159
+In water 14 days  |    187     |   150     |   176   |   159
+In water 17 days  |    192     |   152     |   176   |   161
+In water 25 days  |    198     |   155     |   180   |   161
+In water 30 days  |    207     |   158     |   183   |   166
+---------------------------------------------------------------
+
+
+                        Rapidity of Evaporation
+
+The rapidity with which water is evaporated, that is, the rate of
+drying, depends on the size and shape of the piece and on the
+structure of the wood. An inch board dries more than four times as
+fast as a four-inch plank, and more than twenty times as fast as a
+ten-inch timber. White pine dries faster than oak. A very moist piece
+of pine or oak will, during one hour, lose more than four times as
+much water per square inch from the cross-section, but only one half
+as much from the tangential as from the radial section. In a long
+timber, where the ends or cross-sections form but a small part of the
+drying surface, this difference is not so evident. Nevertheless, the
+ends dry and shrink first, and being opposed in this shrinkage by the
+more moist adjoining parts, they check, the cracks largely
+disappearing as seasoning progresses.
+
+High temperatures are very effective in evaporating the water from
+wood, no matter how humid the air, and a fresh piece of sapwood may
+lose weight in boiling water, and can be dried to quite an extent in
+hot steam.
+
+In drying chemicals or fabrics, all that is required is to provide
+heat enough to vaporize the moisture and circulation enough to carry
+off the vapor thus secured, and the quickest and most economical means
+to these ends may be used. While on the other hand, in drying wood,
+whether in the form of standard stock or the finished product, the
+application of the requisite heat and circulation must be carefully
+regulated throughout the entire process, or warping and checking are
+almost certain to result. Moreover, wood of different shapes and
+thicknesses is very differently effected by the same treatment.
+Finally, the tissues composing the wood, which vary in form and
+physical properties, and which cross each other in regular directions,
+exert their own peculiar influences upon its behavior during drying.
+With our native woods, for instance, summer-wood and spring-wood show
+distinct tendencies in drying, and the same is true in a less degree
+of heartwood, as contrasted with sapwood. Or, again, pronounced
+medullary rays further complicate the drying problem.
+
+
+               Physical Properties that influence Drying
+
+The principal properties which render the drying of wood peculiarly
+difficult are: (1) The irregular shrinkage; (2) the different ways in
+which water is contained; (3) the manner in which moisture transfuses
+through the wood from the center to the surface; (4) the plasticity of
+the wood substance while moist and hot; (5) the changes which take
+place in the hygroscopic and chemical nature of the surface; and (6)
+the difference produced in the total shrinkage by different rates of
+drying.
+
+The shrinkage is unequal in different directions and in different
+portions of the same piece. It is greatest in the circumferential
+direction of the tree, being generally twice as great in this
+direction as in the radial direction. In the longitudinal direction,
+for most woods, it is almost negligible, being from 20 to over 100
+times as great circumferentially as longitudinally.
+
+There is a great variation in different species in this respect.
+Consequently, it follows from necessity that large internal strains
+are set up when the wood shrinks, and were it not for its plasticity
+it would rupture. There is an enormous difference in the total amount
+of shrinkage of different species of wood, varying from a shrinkage of
+only 7 per cent in volume, based on the green dimensions, in the case
+of some of the cedars to nearly 50 per cent in the case of some
+species of eucalyptus.
+
+When the free water in the capillary spaces of the wood fibre is
+evaporated it follows the laws of evaporation from capillary spaces,
+except that the passages are not all free passages, and much of the
+water has to pass out by a process of transfusion through the moist
+cell walls. These cell walls in the green wood completely surround the
+cell cavities so that there are no openings large enough to offer a
+passage to water or air.
+
+The well-known "pits" in the cell walls extend through the secondary
+thickening only, and not through the primary walls. This statement
+applies to the tracheids and parenchyma cells in the conifer
+(gymnosperms), and to the tracheids, parenchyma cells, and the wood
+fibres in the broad-leaved trees (angiosperms); the vessels in the
+latter, however, form open passages except when clogged by ingrowth
+called tyloses, and the resin canals in the former sometimes form
+occasional openings.
+
+By heating the wood above the boiling point, corresponding to the
+external pressure, the free water passes through the cell walls more
+readily.
+
+To remove the moisture from the wood substance requires heat in
+addition to the latent heat of evaporation, because the molecules of
+moisture are so intimately associated with the molecules, minute
+particles composing the wood, that energy is required to separate them
+therefrom.
+
+Carefully conducted experiments show this to be from 16.6 to 19.6
+calories per grain of dry wood in the case of beech, long-leaf pine,
+and sugar maple.
+
+The difficulty imposed in drying, however, is not so much the
+additional heat required as it is in the rate at which the water
+transfuses through the solid wood.
+
+
+
+
+                             SECTION VIII
+
+                        ADVANTAGES IN SEASONING
+
+
+Three most important advantages of seasoning have already been made
+apparent:
+
+     1. Seasoned timber lasts much longer than unseasoned. Since
+     the decay of timber is due to the attacks of wood-destroying
+     fungi, and since the most important condition of the growth
+     of these fungi is water, anything which lessens the amount
+     of water in wood aids in its preservation.
+
+     2. In the case of treated timber, seasoning before treatment
+     greatly increases the effectiveness of the ordinary methods
+     of treatment, and seasoning after treatment prevents the
+     rapid leaching out of the salts introduced to preserve the
+     timber.
+
+     3. The saving in freight where timber is shipped from one
+     place to another. Few persons realize how much water green
+     wood contains, or how much it will lose in a comparatively
+     short time. Experiments along this line with lodge-pole
+     pine, white oak, and chestnut gave results which were a
+     surprise to the companies owning the timber.
+
+Freight charges vary considerably in different parts of the country;
+but a decrease of 35 to 40 per cent in weight is important enough to
+deserve everywhere serious consideration from those in charge of
+timber operations.
+
+When timber is shipped long distances over several roads, as is coming
+to be more and more the case, the saving in freight will make a
+material difference in the cost of lumber operations, irrespective of
+any other advantages of seasoning.
+
+
+                 Prevention of Checking and Splitting
+
+Under present methods much timber is rendered unfit for use by
+improper seasoning. Green timber, particularly when cut during
+January, February, and March, when the roots are most active, contains
+a large amount of water. When exposed to the sun and wind or to high
+temperatures in a drying room, the water will evaporate more rapidly
+from the outer than from the inner parts of the piece, and more
+rapidly from the ends than from the sides. As the water evaporates,
+the wood shrinks, and when the shrinkage is not fairly uniform the
+wood cracks and splits.
+
+When wet wood is piled in the sun, evaporation goes on with such
+unevenness that the timbers split and crack in some cases so badly as
+to become useless for the purpose for which it was intended. Such
+uneven drying can be prevented by careful piling, keeping the logs
+immersed in a log pond until wanted, or by piling or storing under an
+open shed so that the sun cannot get at them.
+
+Experiments have also demonstrated that injury to stock in the way of
+checking and splitting always develops immediately after the stock is
+taken into the dry kiln, and is due to the degree of humidity being
+too low.
+
+The receiving end of the kiln should always be kept moist, where the
+stock has not been steamed before being put into the kiln, as when the
+air is too dry it tends to dry the outside of the stock first--which
+is termed "case-hardening"--and in so doing shrinks and closes up the
+pores. As the material is moved down the kiln (as in the case of
+"progressive kilns"), it absorbs a continually increasing amount of
+heat, which tends to drive off the moisture still present in the
+center of the piece, the pores on the outside having been closed up,
+there is no exit for the vapor or steam that is being rapidly formed
+in the center of the piece. It must find its way out in some manner,
+and in doing so sets up strains, which result either in checking or
+splitting. If the humidity had been kept higher, the outside of the
+piece would not have dried so quickly, and the pores would have
+remained open for the exit of the moisture from the interior of the
+piece, and this trouble would have been avoided. (See also article
+following.)
+
+
+                           Shrinkage of Wood
+
+Since in all our woods, cells with thick walls and cells with thin
+walls are more or less intermixed, and especially as the spring-wood
+and summer-wood nearly always differ from each other in this respect,
+strains and tendencies to warp are always active when wood dries out,
+because the summer-wood shrinks more than the spring-wood, and heavier
+wood in general shrinks more than light wood of the same kind.
+
+If a thin piece of wood after drying is placed upon a moist surface,
+the cells on the under side of the piece take up moisture and swell
+before the upper cells receive any moisture. This causes the under
+side of the piece to become longer than the upper side, and as a
+consequence warping occurs. Soon, however, the moisture penetrates to
+all the cells and the piece straightens out. But while a thin board of
+pine curves laterally it remains quite straight lengthwise, since in
+this direction both shrinkage and swelling are small. If one side of a
+green board is exposed to the sun, warping is produced by the removal
+of water and consequent shrinkage of the side exposed; this may be
+eliminated by the frequent turning of the topmost pieces of the piles
+in order that they may be dried evenly.
+
+As already stated, wood loses water faster from the ends than from the
+longitudinal faces. Hence the ends shrink at a different rate from the
+interior parts. The faster the drying at the surface, the greater is
+the difference in the moisture of the different parts, and hence the
+greater the strains and consequently also the greater amount of
+checking. This becomes very evident when freshly cut wood is placed in
+the sun, and still more when put into a hot, dry kiln. While most of
+these smaller checks are only temporary, closing up again, some large
+radial checks remain and even grow larger as drying progresses. Their
+cause is a different one and will presently be explained. The
+temporary checks not only appear at the ends, but are developed on
+the sides also, only to a much smaller degree. They become especially
+annoying on the surface of thick planks of hardwoods, and also on
+peeled logs when exposed to the sun.
+
+So far we have considered the wood as if made up only of parallel
+fibres all placed longitudinally in the log. This, however, is not the
+case. A large part of the wood is formed by the medullary or pith
+rays. In pine over 15,000 of these occur on a square inch of a
+tangential section, and even in oak the very large rays, which are
+readily visible to the eye, represent scarcely a hundredth part of the
+number which a microscope reveals, as the cells of these rays have
+their length at right angles to the direction of the wood fibres.
+
+If a large pith ray of white oak is whittled out and allowed to dry,
+it is found to shrink greatly in its width, while, as we have stated,
+the fibres to which the ray is firmly grown in the wood do not shrink
+in the same direction. Therefore, in the wood, as the cells of the
+pith ray dry they pull on the longitudinal fibres and try to shorten
+them, and, being opposed by the rigidity of the fibres, the pith ray
+is greatly strained. But this is not the only strain it has to bear.
+Since the fibres shrink as much again as the pith ray, in this its
+longitudinal direction, the fibres tend to shorten the ray, and the
+latter in opposing this prevents the former from shrinking as much as
+they otherwise would.
+
+Thus the structure is subjected to two severe strains at right angles
+to each other, and herein lies the greatest difficulty of wood
+seasoning, for whenever the wood dries rapidly these fibres have not
+the chance to "give" or accommodate themselves, and hence fibres and
+pith rays separate and checking results, which, whether visible or
+not, are detrimental in the use of the wood.
+
+The contraction of the pith rays parallel to the length of the board
+is probably one of the causes of the small amount of longitudinal
+shrinkage which has been observed in boards. This smaller shrinkage of
+the pith rays along the radius of the log (the length of the pith
+ray), opposing the shrinkage of the fibres in this direction, becomes
+one of the causes of the second great trouble in wood seasoning,
+namely, the difference in the shrinkage along the radius and that
+along the rings or tangent. This greater tangential shrinkage appears
+to be due in part to the causes just mentioned, but also to the fact
+that the greatly shrinking bands of summer-wood are interrupted along
+the radius by as many bands of porous spring-wood, while they are
+continuous in the tangential direction. In this direction, therefore,
+each such band tends to shrink, as if the entire piece were composed
+of summer-wood, and since the summer-wood represents the greater part
+of the wood substance, this greater tendency to tangential shrinkage
+prevails.
+
+The effect of this greater tangential shrinkage effects every phase of
+woodworking. It leads to permanent checks and causes the log or piece
+to split open on drying. Sawed in two, the flat sides of the log
+become convex; sawed into timber, it checks along the median line of
+the four faces, and if converted into boards, the latter checks
+considerably from the end through the center, all owing to the greater
+tangential shrinkage of the wood.
+
+Briefly, then, shrinkage of wood is due to the fact that the cell
+walls grow thinner on drying. The thicker cell walls and therefore the
+heavier wood shrinks most, while the water in the cell cavities does
+not influence the volume of the wood.
+
+Owing to the great difference of cells in shape, size, and thickness
+of walls, and still more in their arrangement, shrinkage is not
+uniform in any kind of wood. This irregularity produces strains, which
+grow with the difference between adjoining cells and are greatest at
+the pith rays. These strains cause warping and checking, but exist
+even where no outward signs are visible. They are greater if the wood
+is dried rapidly than if dried slowly, but can never be entirely
+avoided.
+
+Temporary checks are caused by the more rapid drying of the outer
+parts of any stick; permanent checks are due to the greater shrinkage,
+tangentially, along the rings than along the radius. This, too, is the
+cause of most of the ordinary phenomena of shrinkage, such as the
+difference in behavior of the entire and quartered logs, "bastard"
+(tangent) and rift (radial) boards, etc., and explains many of the
+phenomena erroneously attributed to the influence of bark, or of the
+greater shrinkage of outer and inner parts of any log.
+
+Once dry, wood may be swelled again to its original size by soaking in
+water, boiling, or steaming. Soaked pieces on drying shrink again as
+before; boiled and steamed pieces do the same, but to a slightly less
+degree. Neither hygroscopicity, _i.e._, the capacity of taking up
+water, nor shrinkage of wood can be overcome by drying at temperatures
+below 200 degrees Fahrenheit. Higher temperatures, however, reduce
+these qualities, but nothing short of a coaling heat robs wood of the
+capacity to shrink and swell.
+
+Rapidly dried in a kiln, the wood of oak and other hardwoods
+"case-harden," that is, the outer part dries and shrinks before the
+interior has a chance to do the same, and thus forms a firm shell or
+case of shrunken, commonly checked wood around the interior. This
+shell does not prevent the interior from drying, but when this drying
+occurs the interior is commonly checked along the medullary rays,
+commonly called "honeycombing" or "hollow-horning." In practice this
+occurrence can be prevented by steaming or sweating the wood in the
+kiln, and still better by drying the wood in the open air or in a shed
+before placing in the kiln. Since only the first shrinkage is apt to
+check the wood, any kind of lumber which has once been air-dried
+(three to six months for one-inch stuff) may be subjected to kiln heat
+without any danger from this source.
+
+Kept in a bent or warped condition during the first shrinkage, the
+wood retains the shape to which it has been bent and firmly opposes
+any attempt at subsequent straightening.
+
+Sapwood, as a rule, shrinks more than heartwood of the same weight,
+but very heavy heartwood may shrink more than lighter sapwood. The
+amount of water in wood is no criterion of its shrinkage, since in wet
+wood most of the water is held in the cavities, where it has no effect
+on the volume.
+
+The wood of pine, spruce, cypress, etc., with its very regular
+structure, dries and shrinks evenly, and suffers much less in
+seasoning than the wood of broad-leaved (hardwood) trees. Among the
+latter, oak is the most difficult to dry without injury.
+
+Desiccating the air with certain chemicals will cause the wood to dry,
+but wood thus dried at 80 degrees Fahrenheit will still lose water in
+the kiln. Wood dried at 120 degrees Fahrenheit loses water still if
+dried at 200 degrees Fahrenheit, and this again will lose more water
+if the temperature be raised, so that _absolutely dry wood_ cannot be
+obtained, and chemical destruction sets in before all the water is
+driven off.
+
+On removal from the kiln, the dry wood at once takes up moisture from
+the air, even in the driest weather. At first the absorption is quite
+rapid; at the end of a week a short piece of pine, 1-1/2 inches thick,
+has regained two thirds of, and, in a few months, all the moisture
+which it had when air-dry, 8 to 10 per cent, and also its former
+dimensions. In thin boards all parts soon attain the same degree of
+dryness. In heavy timbers the interior remains more moist for many
+months, and even years, than the exterior parts. Finally an
+equilibrium is reached, and then only the outer parts change with the
+weather.
+
+With kiln-dried woods all parts are equally dry, and when exposed, the
+moisture coming from the air must pass through the outer parts, and
+thus the order is reversed. Ordinary timber requires months before it
+is at its best. Kiln-dried timber, if properly handled, is prime at
+once.
+
+Dry wood if soaked in water soon regains its original volume, and in
+the heartwood portion it may even surpass it; that is to say, swell to
+a larger dimension than it had when green. With the soaking it
+continues to increase in weight, the cell cavities filling with water,
+and if left many months all pieces sink. Yet after a year's immersion
+a piece of oak 2 by 2 inches and only 6 inches long still contains
+air; _i.e._, it has not taken up all the water it can. By rafting or
+prolonged immersion, wood loses some of its weight, soluble materials
+being leached out, but it is not impaired either as fuel or as
+building material. Immersion, and still more boiling and steaming,
+reduce the hygroscopicity of wood and therefore also the troublesome
+"working," or shrinking and swelling.
+
+Exposure in dry air to a temperature of 300 degrees Fahrenheit for a
+short time reduces but does not destroy the hygroscopicity, and with
+it the tendency to shrink and swell. A piece of red oak which has been
+subjected to a temperature of over 300 degrees Fahrenheit still swells
+in hot water and shrinks in a dry kiln.
+
+
+                           Expansion of Wood
+
+It must not be forgotten that timber, in common with every other
+material, expands as well as contracts. If we extract the moisture
+from a piece of wood and so cause it to shrink, it may be swelled to
+its original volume by soaking it in water, but owing to the
+protection given to most timber in dwelling-houses it is not much
+affected by wet or damp weather. The shrinkage is more apparent, more
+lasting, and of more consequence to the architect, builder, or owner
+than the slight expansion which takes place, as, although the amount
+of moisture contained in wood varies with the climate conditions, the
+consequence of dampness or moisture on good timber used in houses only
+makes itself apparent by the occasional jamming of a door or window in
+wet or damp weather.
+
+Considerable expansion, however, takes place in the wood-paving of
+streets, and when this form of paving was in its infancy much trouble
+occurred owing to all allowances not having been made for this
+contingency, the trouble being doubtless increased owing to the blocks
+not being properly seasoned; curbing was lifted or pushed out of line
+and gully grids were broken by this action. As a rule in street paving
+a space of one or two inches wide is now left next to the curb, which
+is filled with sand or some soft material, so that the blocks may
+expand longitudinally without injuring the contour or affecting the
+curbs. But even with this arrangement it is not at all unusual for an
+inch or more to have to be cut off paving blocks parallel to the
+channels some time after the paving has been laid, owing to the
+expansion of the wood exceeding the amounts allowed.
+
+Considerable variation occurs in the expansion of wood blocks, and it
+is noticeable in the hardwoods as well as in the softwoods, and is
+often greater in the former than in the latter.
+
+Expansion takes place in the direction of the length of the blocks as
+they are laid across the street, and causes no trouble in the other
+direction, the reason being that the lengthway of a block of wood is
+across the grain, of the timber, and it expands or contracts as a
+plank does. On one occasion, in a roadway forty feet wide, expansion
+occurred until it amounted to four inches on each side, or eight
+inches in all. This continual expansion and contraction is doubtless
+the cause of a considerable amount of wood street-paving bulging and
+becoming filled with ridges and depressions.
+
+
+                    Elimination of Stain and Mildew
+
+A great many manufacturers, and particularly those located in the
+Southern States, experience a great amount of difficulty in their
+timber becoming stained and mildewed. This is particularly true with
+gum wood, as it will frequently stain and mould in twenty-four hours,
+and they have experienced so much of this trouble that they have, in a
+great many instances, discontinued cutting it during the summer
+season.
+
+If this matter were given proper attention they should be able to
+eliminate a great deal of this difficulty, as no doubt they will find
+after investigation that the mould has been caused by the stock being
+improperly piled to the weather.
+
+Freshly sawn wood, placed in close piles during warm, damp weather in
+the months of July and August, presents especially favorable
+conditions for mould and stain. In all cases it is the moist condition
+and retarded drying of the wood which causes this. Therefore, any
+method which will provide for the rapid drying of the wood before or
+after piling will tend to prevent the difficulty, and the best method
+for eliminating mould is (1) to provide for as little delay as
+possible between the felling of the tree, and its manufacture into
+rough products before the sap has had an opportunity of becoming sour.
+This is especially necessary with trees felled from April to
+September, in the region north of the Gulf States, and from March to
+November in the latter, while the late fall and winter cutting should
+all be worked up by March or April. (2) The material should be piled
+to the weather immediately after being sawn or cut, and every
+precaution should be taken in piling to facilitate rapid drying, by
+keeping the piles or ricks up off the ground. (3) All weeds (and
+emphasis should be placed on the ALL) and other vegetation should be
+kept well clear of the piles, in order that the air may have a clear
+and unobstructed passage through and around the piles, and (4) the
+piles should be so constructed that each stick or piece will have as
+much air space about it as it is possible to give to it.
+
+If the above instructions are properly carried out, there will be
+little or no difficulty experienced with mould appearing on the
+lumber.
+
+
+
+
+                              SECTION IX
+
+                      DIFFICULTIES OF DRYING WOOD
+
+
+Seasoning and kiln-drying is so important a process in the manufacture
+of woods that a need is keenly felt for fuller information regarding
+it, based upon scientific study of the behavior of various species at
+different mechanical temperatures and under different mechanical
+drying processes. The special precautions necessary to prevent loss of
+strength or distortion of shape render the drying of wood especially
+difficult.
+
+All wood when undergoing a seasoning process, either natural (by air)
+or mechanical (by steam or heat in a dry kiln), checks or splits more
+or less. This is due to the uneven drying-out of the wood and the
+consequent strains exerted in opposite directions by the wood fibres
+in shrinking. This shrinkage, it has been proven, takes place both
+end-wise and across the grain of the wood. The old tradition that wood
+does not shrink end-wise has long since been shattered, and it has
+long been demonstrated that there is an end-wise shrinkage.
+
+In some woods it is very light, while in others it is easily
+perceptible. It is claimed that the average end shrinkage, taking all
+the woods, is only about 1-1/2 per cent. This, however, probably has
+relation to the average shrinkage on ordinary lumber as it is used and
+cut and dried. Now if we depart from this and take veneer, or basket
+stock, or even stave bolts where they are boiled, causing swelling
+both end-wise and across the grain or in dimension, after they are
+thoroughly dried, there is considerably more evidence of end
+shrinkage. In other words, a slack barrel stave of elm, say, 28 or 30
+inches in length, after being boiled might shrink as much in
+thoroughly drying-out as compared to its length when freshly cut, as a
+12-foot elm board.
+
+It is in cutting veneer that this end shrinkage becomes most readily
+apparent. In trimming with scoring knives it is done to exact measure,
+and where stock is cut to fit some specific place there has been
+observed a shrinkage on some of the softer woods, like cottonwood,
+amounting to fully 1/8 of an inch in 36 inches. And at times where
+drying has been thorough the writer has noted a shrinkage of 1/8 of an
+inch on an ordinary elm cabbage-crate strip 36 inches long, sawed from
+the log without boiling.
+
+There are really no fixed rules of measurement or allowance, however,
+because the same piece of wood may vary under different conditions,
+and, again, the grain may cross a little or wind around the tree, and
+this of itself has a decided effect on the amount of what is termed
+"end shrinkage."
+
+There is more checking in the wood of the broad-leaf (hardwood) trees
+than in that of the coniferous (softwood) trees, more in sapwood than
+in heartwood, and more in summer-wood than in spring-wood.
+
+Inasmuch as under normal conditions of weather, water evaporates less
+rapidly during the early seasoning of winter, wood that is cut in the
+autumn and early winter is considered less subject to checking than
+that which is cut in spring and summer.
+
+Rapid seasoning, except after wood has been thoroughly soaked or
+steamed, almost invariably results in more or less serious checking.
+All hardwoods which check or warp badly during the seasoning should be
+reduced to the smallest practicable size before drying to avoid the
+injuries involved in this process, and wood once seasoned _should
+never again be exposed to the weather_, since all injuries due to
+seasoning are thereby aggravated.
+
+Seasoning increases the strength of wood in every respect, and it is
+therefore of great importance to protect the wood against moisture.
+
+
+                  Changes rendering Drying difficult
+
+An important property rendering drying of wood peculiarly difficult is
+the changes which occur in the hygroscopic properties of the surface
+of a stick, and the rate at which it will allow moisture to pass
+through it. If wood is dried rapidly the surface soon reaches a
+condition where the transfusion is greatly hindered and sometimes
+appears almost to cease. The nature of this action is not well
+understood and it differs greatly in different species. Bald cypress
+(_Taxodium distichum_) is an example in which this property is
+particularly troublesome. The difficulty can be overcome by regulating
+the humidity during the drying operation. It is one of the factors
+entering into production of what is called "case-hardening" of wood,
+where the surface of the piece becomes hardened in a stretched or
+expanded condition, and subsequent shrinkage of the interior causes
+"honeycombing," "hollow-horning," or internal checking. The outer
+surface of the wood appears to undergo a chemical change in the nature
+of hydrolization or oxidization, which alters the rate of absorption
+and evaporation in the air.
+
+As the total amount of shrinkage varies with the rate at which the
+wood is dried, it follows that the outer surface of a rapidly dried
+board shrinks less than the interior. This sets up an internal stress,
+which, if the board be afterward resawed into two thinner boards by
+slicing it through the middle, causes the two halves to cup with their
+convex surfaces outward. This effect may occur even though the
+moisture distribution in the board has reached a uniform condition,
+and the board is thoroughly dry before it is resawed. It is distinct
+from the well-known "case-hardening" effect spoken of above, which is
+caused by unequal moisture conditions.
+
+The manner in which the water passes from the interior of a piece of
+wood to its surface has not as yet been fully determined, although it
+is one of the most important factors which influence drying. This must
+involve a transfusion of moisture through the cell walls, since, as
+already mentioned, except for the open vessels in the hardwoods, free
+resin ducts in the softwoods, and possibly the intercellular spaces,
+the cells of green wood are enclosed by membranes and the water must
+pass through the walls or the membranes of the pits. Heat appears to
+increase this transfusion, but experimental data are lacking.
+
+It is evident that to dry wood properly a great many factors must be
+taken into consideration aside from the mere evaporation of moisture.
+
+
+                  Losses Due to Improper Kiln-drying
+
+In some cases there is practically no loss in drying, but more often
+it ranges from 1 to 3 per cent, and 7 to 10 per cent in refractory
+woods such as gum. In exceptional instances the losses are as high as
+33 per cent.
+
+In air-drying there is little or no control over the process; it may
+take place too rapidly on some days and too slowly on others, and it
+may be very non-uniform.
+
+Hardwoods in large sizes almost invariably check.
+
+By proper kiln-drying these unfavorable circumstances may be
+eliminated. However, air-drying is unquestionably to be preferred to
+bad kiln-drying, and when there is any doubt in the case it is
+generally safer to trust to air-drying.
+
+If the fundamental principles are all taken care of, green lumber can
+be better dried in the dry kiln.
+
+
+                 Properties of Wood that affect Drying
+
+It is clear, from the previous discussion of the structure of wood,
+that this property is of first importance among those influencing the
+seasoning of wood. The free water way usually be extracted quite
+readily from porous hardwoods. The presence of tyloses in white oak
+makes even this a difficult problem. On the other hand, its more
+complex structure usually renders the hygroscopic moisture quite
+difficult to extract.
+
+The lack of an open, porous structure renders the transfusion of
+moisture through some woods very slow, while the reverse may be true
+of other species. The point of interest is that all the different
+variations in structure affect the drying rates of woods. The
+structure of the gums suggests relatively easy seasoning.
+
+Shrinkage is a very important factor affecting the drying of woods.
+Generally speaking, the greater the shrinkage the more difficult it is
+to dry wood. Wood shrinks about twice as much tangentially as
+radially, thus introducing very serious stresses which may cause loss
+in woods whose total shrinkage is large. It has been found that the
+amount of shrinkage depends, to some extent, on the rate and
+temperature at which woods season. Rapid drying at high or low
+temperature results in slight shrinkage, while slow drying, especially
+at high temperature, increases the shrinkage.
+
+As some woods must be dried in one way and others in other ways, to
+obtain the best general results, this effect may be for the best in
+one case and the reverse in others. As an example one might cite the
+case of Southern white oak. This species must be dried very slowly at
+low temperatures in order to avoid the many evils to which it is heir.
+It is interesting to note that this method tends to increase the
+shrinkage, so that one might logically expect such treatment merely to
+aggravate the evils. Such is not the case, however, as too fast drying
+results in other defects much worse than that of excessive shrinkage.
+
+Thus we see that the shrinkage of any given species of wood depends to
+a great extent on the method of drying. Just how much the shrinkage of
+gum is affected by the temperature and drying rate is not known at
+present. There is no doubt that the method of seasoning affects the
+shrinkage of the gums, however. It is just possible that these woods
+may shrink longitudinally more than is normal, thus furnishing another
+cause for their peculiar action under certain circumstances. It has
+been found that the properties of wood which affect the seasoning of
+the gums are, in the order of their importance: (1) The indeterminate
+and erratic grain; (2) the uneven shrinkage with the resultant
+opposing stresses; (3) the plasticity under high temperature while
+moist; and (4) the slight apparent lack of cohesion between the
+fibres. The first, second, and fourth properties are clearly
+detrimental, while the third may possibly be an advantage in reducing
+checking and "case-hardening."
+
+The grain of the wood is a prominent factor also affecting the
+problem. It is this factor, coupled with uneven shrinkage, which is
+probably responsible, to a large extent, for the action of the gums in
+drying. The grain may be said to be more or less indeterminate. It is
+usually spiral, and the spiral may reverse from year to year of the
+tree's growth. When a board in which this condition exists begins to
+shrink, the result is the development of opposing stresses, the effect
+of which is sometimes disastrous. The shrinkage around the knots seems
+to be particularly uneven, so that checking at the knots is quite
+common.
+
+Some woods, such as Western red cedar, redwood, and eucalyptus, become
+very plastic when hot and moist. The result of drying-out the free
+water at high temperature may be to collapse the cells. The gums are
+known to be quite soft and plastic, if they are moist, at high
+temperature, but they do not collapse so far as we have been able to
+determine.
+
+The cells of certain species of wood appear to lack cohesion,
+especially at the junction between the annual rings. As a result,
+checks and ring shakes are very common in Western larch and hemlock.
+The parenchyma cells of the medullary rays in oak do not cohere
+strongly and often check open, especially when steamed too severely.
+
+
+                   Unsolved Problems in Kiln-drying
+
+     1. Physical data of the properties of wood in relation to
+     heat are meagre.
+
+     2. Figures on the specific heat of wood are not readily
+     available, though upon this rests not only the exact
+     operation of heating coils for kilns, but the theory of
+     kiln-drying as a whole.
+
+     3. Great divergence is shown in the results of experiments
+     in the conductivity of wood. It remains to be seen whether
+     the known variation of conductivity with moisture content
+     will reduce these results to uniformity.
+
+     4. The maximum or highest temperature to which the different
+     species of wood may be exposed without serious loss of
+     strength has not yet been determined.
+
+     5. The optimum or absolute correct temperature for drying
+     the different species of wood is as yet entirely unsettled.
+
+     6. The inter-relation between wood and water is as
+     imperfectly known to dry-kiln operators as that between wood
+     and heat.
+
+     7. What moisture conditions obtain in a stick of air-dried
+     wood?
+
+     8. How is the moisture distinguished?
+
+     9. What is its form?
+
+     10. What is the meaning of the peculiar surface conditions
+     which even in air-dried wood appear to indicate incipient
+     "case-hardening"?
+
+     11. The manner in which the water passes from the interior
+     of a piece of wood to its surface has not as yet been fully
+     determined.
+
+These questions can be answered thus far only by speculation or, at
+best, on the basis of incomplete data.
+
+Until these problems are solved, kiln-drying must necessarily remain
+without the guidance of complete scientific theory.
+
+A correct understanding of the principles of drying is rare, and
+opinions in regard to the subject are very diverse. The same lack of
+knowledge exists in regard to dry kilns. The physical properties of
+the wood which complicate the drying operation and render it distinct
+from that of merely evaporating free water from some substance like a
+piece of cloth must be studied experimentally. It cannot well be
+worked out theoretically.
+
+
+
+
+                               SECTION X
+
+                         HOW WOOD IS SEASONED
+
+
+                           Methods of Drying
+
+The choice of a method of drying depends largely upon the object in
+view. The principal objects may be grouped under three main heads, as
+follows:
+
+     1. To reduce shipping weight.
+
+     2. To reduce the quantity necessary to carry in stock.
+
+     3. To prepare the wood for its ultimate use and improve its
+     qualities.
+
+When wood will stand the temperature without excessive checking or
+undue shrinkage or loss in strength, the first object is most readily
+attained by heating the wood above the boiling point in a closed
+chamber, with a large circulation of air or vapor, so arranged that
+the excess steam produced will escape. This process manifestly does
+not apply to many of the hardwoods, but is applicable to many of the
+softwoods. It is used especially in the northwestern part of the
+United States, where Douglas fir boards one inch thick are dried in
+from 40 to 65 hours, and sometimes in as short a time as 24 hours. In
+the latter case superheated steam at 300 degrees Fahrenheit was forced
+into the chamber but, of course, the lumber could not be heated
+thereby much above the boiling point so long as it contained any free
+water.
+
+This lumber, however, contained but 34 per cent moisture to start
+with, and the most rapid rate was 1.6 per cent loss per hour.
+
+The heat of evaporation may be supplied either by superheated steam or
+by steam pipes within the kiln itself.
+
+The quantity of wood it is necessary to carry in stock is naturally
+reduced when either of the other two objects is attained and,
+therefore, need not necessarily be discussed.
+
+In drying to prepare for use and to improve quality, careful and
+scientific drying is called for. This applies more particularly to the
+hardwoods, although it may be required for softwoods also.
+
+
+                    Drying at Atmospheric Pressure
+
+Present practice of kiln-drying varies tremendously and there is no
+uniformity or standard method.
+
+Temperatures vary anywhere from 65 to 165 degrees Fahrenheit, or even
+higher, and inch boards three to six months on the sticks are being
+dried in from four days to three weeks, and three-inch material in
+from two to five months.
+
+All methods in use at atmospheric pressure may be classified under the
+following headings. The kilns may be either progressive or
+compartment, and preliminary steaming may or may not be used with any
+one of these methods:
+
+     1. Dry air heated. This is generally obsolete.
+     2. Moist air.
+         _a._ Ventilated.
+         _b._ Forced draft.
+         _c._ Condensing.
+         _d._ Humidity regulated.
+         _e._ Boiling.
+     3. Superheated steam.
+
+
+                   Drying under Pressure and Vacuum
+
+Various methods of drying wood under pressures other than atmospheric
+have been tried. Only a brief mention of this subject will be made.
+Where the apparatus is available probably the quickest way to dry wood
+is first to heat it in saturated steam at as high a temperature as the
+species can endure without serious chemical change until the heat has
+penetrated to the center, then follow this with a vacuum.
+
+By this means the self-contained specific heat of the wood and the
+water is made available for the evaporation, and the drying takes
+place from the inside outwardly, just the reverse of that which occurs
+by drying by means of external heat.
+
+When the specimen has cooled this process is then to be repeated until
+it has dried down to fibre-saturation point. It cannot be dried much
+below this point by this method, since the absorption during the
+heating operation will then equal the evaporation during the cooling.
+It may be carried further, however, by heating in partially humidified
+air, proportioning the relative humidity each time it is heated to the
+degree of moisture present in the wood.
+
+The point to be considered in this operation is that during the
+heating process no evaporation shall be allowed to take place, but
+only during the cooling. In this way surface drying and
+"case-hardening" are prevented since the heat is from within and the
+moisture passes from the inside outwardly. However, with some species,
+notably oak, surface cracks appear as a network of fine checks along
+the medullary rays.
+
+In the first place, it should be borne in mind that it is the heat
+which produces evaporation and not the air nor any mysterious property
+assigned to a "vacuum."
+
+For every pound of water evaporated at ordinary temperatures
+approximately 1,000 British thermal units of heat are used up, or
+"become latent," as it is called. This is true whether the evaporation
+takes place in a vacuum or under a moderate air pressure. If this heat
+is not supplied from an outside source it must be supplied by the
+water itself (or the material being dried), the temperature of which
+will consequently fall until the surrounding space becomes saturated
+with vapor at a pressure corresponding to the temperature which the
+water has reached; evaporation will then cease. The pressure of the
+vapor in a space saturated with water vapor increases rapidly with
+increase of temperature. At a so-called vacuum of 28 inches, which is
+about the limit in commercial operations, and in reality signifies an
+actual pressure of 2 inches of mercury column, the space will be
+saturated with vapor at 101 degrees Fahrenheit. Consequently, no
+evaporation will take place in such a vacuum unless the water be
+warmer than 101 degrees Fahrenheit, provided there is no air leakage.
+The qualification in regard to air is necessary, for the sake of
+exactness, for the following reason: In any given space the total
+actual pressure is made up of the combined pressures of all the gases
+present. If the total pressure ("vacuum") is 2 inches, and there is no
+air present, it is all produced by the water vapor (which saturates
+the space at 101 degrees Fahrenheit); but if some air is present and
+the total pressure is still maintained at 2 inches, then there must be
+less vapor present, since the air is producing part of the pressure
+and the space is no longer saturated at the given temperature.
+Consequently further evaporation may occur, with a corresponding
+lowering of the temperature of the water, until a balance is again
+reached. Without further explanation it is easy to see that but little
+water can be evaporated by a vacuum alone without addition of heat,
+and that the prevalent idea that a vacuum can of itself produce
+evaporation is a fallacy. If heat be supplied to the water, however,
+either by conduction or radiation, evaporation will take place in
+direct proportion to the amount of heat supplied, so long as the
+pressure is kept down by the vacuum pump.
+
+At 30 inches of mercury pressure (one atmosphere) the space becomes
+saturated with vapor and equilibrium is established at 212 degrees
+Fahrenheit. If heat be now supplied to the water, however, evaporation
+will take place in proportion to the amount of heat supplied, so long
+as the pressure remains that of one atmosphere, just as in the case of
+the vacuum. Evaporation in this condition, where the vapor pressure at
+the temperature of the water is equal to the gas pressure on the
+water, is commonly called "boiling," and the saturated vapor entirely
+displaces the air under continuous operation. Whenever the space is
+not saturated with vapor, whether air is present or not, evaporation
+will take place, by boiling if no air be present or by diffusion under
+the presence of air, until an equilibrium between temperature and
+vapor pressure is resumed.
+
+Relative humidity is simply the ratio of the actual vapor pressure
+present in a given space to the vapor pressure when the space is
+saturated with vapor at the given temperature. It matters not whether
+air be present or not. One hundred per cent humidity means that the
+space contains all the vapor which it can hold at the given
+temperature--it is saturated. Thus at 100 per cent humidity and 212
+degrees Fahrenheit the space is saturated, and since the pressure of
+saturated vapor at this temperature is one atmosphere, no air can be
+present under these conditions. If, however, the total pressure at
+this temperature were 20 pounds (5 pounds gauge), then it would mean
+that there was 5 pounds air pressure present in addition to the vapor,
+yet the space would still be saturated at the given temperature.
+Again, if the temperature were 101 degrees Fahrenheit, the pressure of
+saturated vapor would be only 1 pound, and the additional pressure of
+14 pounds, if the total pressure were atmospheric, would be made up of
+air. In order to have no air present and the space still saturated at
+101 degrees Fahrenheit, the total pressure must be reduced to 1 pound
+by a vacuum pump. Fifty per cent relative humidity, therefore,
+signifies that only half the amount of vapor required to saturate the
+space at the given temperature is present. Thus at 212 degrees
+Fahrenheit temperature the vapor pressure would only be 7-1/2 pounds
+(vacuum of 15 inches gauge). If the total pressure were atmospheric,
+then the additional 7-1/2 pounds would be simply air.
+
+"Live steam" is simply water-saturated vapor at a pressure usually
+above atmospheric. We may just as truly have live steam at pressures
+less than atmospheric, at a vacuum of 28 inches for instance. Only in
+the latter case its temperature would be lower, _viz._, 101 degrees
+Fahrenheit.
+
+Superheated steam is nothing more than water vapor at a relative
+humidity less than saturation, but is usually considered at pressures
+above atmospheric, and in the absence of air. The atmosphere at, say,
+50 per cent relative humidity really contains superheated steam or
+vapor, the only difference being that it is at a lower temperature and
+pressure than we are accustomed to think of in speaking of superheated
+steam, and it has air mixed with it to make up the deficiency in
+pressure below the atmosphere.
+
+Two things should now be clear; that evaporation is produced by heat
+and that the presence or absence of air does not influence the amount
+of evaporation. It does, however, influence the rate of evaporation,
+which is retarded by the presence of air. The main things influencing
+evaporation are, first, the quantity of heat supplied and, second, the
+relative humidity of the immediately surrounding space.
+
+
+                      Drying by Superheated Steam
+
+What this term really signifies is simply water vapor in the absence
+of air in a condition of less than saturation. Kilns of this type are,
+properly speaking, vapor kilns, and usually operate at atmospheric
+pressure, but may be used at greater pressures or at less pressures.
+As stated before, the vapor present in the air at any humidity less
+than saturation is really "superheated steam," only at a lower
+pressure than is ordinarily understood by this term, and mixed with
+air. The main argument in favor of this process seems to be based on
+the idea that steam is moist heat. This is true, however, only when
+the steam is near saturation. When it is superheated it is just as dry
+as air containing the same relative humidity. For instance, steam at
+atmospheric pressure and heated to 248 degrees Fahrenheit has a
+relative humidity of only 50 per cent and is just as dry as air
+containing the same humidity. If heated to 306 degrees Fahrenheit, its
+relative humidity is reduced to 20 per cent; that is to say, the ratio
+of its actual vapor pressure (one atmosphere) to the pressure of
+saturated vapor at this temperature (five atmospheres) is 1:5, or 20
+per cent. Superheated vapor in the absence of air, however, parts with
+its heat with great rapidity and finally becomes saturated when it has
+lost all of its ability to cause evaporation. In this respect it is
+more moist than air when it comes in contact with bodies which are at
+a lower temperature. When saturated steam is used to heat the lumber
+it can raise the temperature of the latter to its own temperature, but
+cannot produce evaporation unless, indeed, the pressure is varied.
+Only by the heat supplied above the temperature of saturation can
+evaporation be produced.
+
+
+                         Impregnation Methods
+
+Methods of partially overcoming the shrinkage by impregnation of the
+cell walls with organic materials closely allied to the wood substance
+itself are in use. In one of these which has been patented, sugar is
+used as the impregnating material, which is subsequently hardened or
+"caramelized" by heating. Experiments which the United States Forest
+Service has made substantiate the claims that the sugar does greatly
+reduce the shrinkage of the wood; but the use of impregnation
+processes is determined rather from a financial economic standpoint
+than by the physical result obtained.
+
+Another process consists in passing a current of electricity through
+the wet boards or through the green logs before sawing. It is said
+that the ligno cellulose and the sap are thus transformed by
+electrolysis, and that the wood subsequently dries more rapidly.
+
+
+                        Preliminary Treatments
+
+In many dry kiln operations, especially where the kilns are not
+designed for treatments with very moist air, the wood is allowed to
+air-season from several months to a year or more before running it
+into the dry kiln. In this way the surface dries below its
+fibre-saturation point and becomes hardened or "set" and the
+subsequent shrinkage is not so great. Moreover, there is less danger
+of surface checking in the kiln, since the surface has already passed
+the danger point. Many woods, however, check severely in air-drying or
+case-harden in the air. It is thought that such woods can be
+satisfactorily handled in a humidity-regulated kiln direct from the
+saw.
+
+Preliminary steaming is frequently used to moisten the surface if
+case-hardened, and to heat the lumber through to the center before
+drying begins. This is sometimes done in a separate chamber, but more
+often in a compartment of the kiln itself, partitioned off by means of
+a curtain which can be raised or lowered as circumstances require.
+This steaming is usually conducted at atmospheric pressure and
+frequently condensed steam is used at temperatures far below 212
+degrees Fahrenheit. In a humidity-regulated kiln this preliminary
+treatment may be omitted, since nearly saturated conditions can be
+maintained and graduated as the drying progresses.
+
+Recently the process of steaming at pressures up to 20 pounds gauge in
+a cylinder for short periods of time, varying from 5 to 20 minutes, is
+being advocated in the United States. The truck load is run into the
+cylinder, steamed, and then taken directly out into the air. It may
+subsequently be placed in the dry kiln if further drying is desired.
+The self-contained heat of the wood evaporates considerable moisture,
+and the sudden drying of the boards causes the shrinkage to be reduced
+slightly in some cases. Such short periods of steaming under 20 pounds
+pressure do not appear to injure the wood mechanically, although they
+do darken the color appreciably, especially of the sapwood of the
+species having a light-colored sap, as black walnut (_Juglans nigra_)
+and red gum (_Liquidamber styraciflua_). Longer periods of steaming
+have been found to weaken the wood. There is a great difference in the
+effect on different species, however.
+
+Soaking wood for a long time before drying has been practised, but
+experiments indicate that no particularly beneficial results, from the
+drying standpoint, are attained thereby. In fact, in some species
+containing sugars and allied substances it is probably detrimental
+from the shrinkage standpoint. If soaked in boiling water some species
+shrink and warp more than if dried without this treatment.
+
+In general, it may be said that, except possibly for short-period
+steaming as described above, steaming and soaking hardwoods at
+temperatures of 212 degrees Fahrenheit or over should be avoided if
+possible.
+
+It is the old saying that wood put into water shortly after it is
+felled, and left in water for a year or more, will be perfectly
+seasoned after a short subsequent exposure to the air. For this reason
+rivermen maintain that timber is made better by rafting. Herzenstein
+says: "Floating the timber down rivers helps to wash out the sap, and
+hence must be considered as favorable to its preservation, the more so
+as it enables it to absorb more preservative."
+
+Wood which has been buried in swamps is eagerly sought after by
+carpenters and joiners, because it has lost all tendency to warp and
+twist. When first taken from the swamp the long-immersed logs are very
+much heavier than water, but they dry with great rapidity. A cypress
+log from the Mississippi Delta, which two men could barely handle at
+the time it was taken out some years ago, has dried out so much since
+then that to-day one man can lift it with ease. White cedar telegraph
+poles are said to remain floating in the water of the Great Lakes
+sometimes for several years before they are set in lines and to last
+better than freshly cut poles.
+
+It is very probable that immersion for long periods in water does
+materially hasten subsequent seasoning. The tannins, resins,
+albuminous materials, etc., which are deposited in the cell walls of
+the fibres of green wood, and which prevent rapid evaporation of the
+water, undergo changes when under water, probably due to the action of
+bacteria which live without air, and in the course of time many of
+these substances are leached out of the wood. The cells thereby become
+more and more permeable to water, and when the wood is finally brought
+into the air the water escapes very rapidly and very evenly.
+Herzenstein's statement that wood prepared by immersion and subsequent
+drying will absorb more preservative, and that with greater rapidity,
+is certainly borne out by experience in the United States.
+
+It is sometimes claimed that all seasoning preparatory to treatment
+with a substance like tar oil might be done away with by putting the
+green wood into a cylinder with the oil and heating to 225 degrees
+Fahrenheit, thus driving the water off in the form of steam, after
+which the tar oil would readily penetrate into the wood. This is the
+basis of the so-called "Curtiss process" of timber treatment. Without
+going into any discussion of this method of creosoting, it may be said
+that the same objection made for steaming holds here. In order to get
+a temperature of 212 degrees Fahrenheit in the center of the treated
+wood, the outside temperature would have to be raised so high that the
+strength of the wood might be seriously injured.
+
+A company on the Pacific coast which treats red fir piling asserts
+that it avoids this danger by leaving the green timber in the tar oil
+at a temperature which never exceeds 225 degrees Fahrenheit for from
+five to twelve hours, until there is no further evidence of water
+vapor coming out of the wood. The tar oil is then run out, and a
+vacuum is created for about an hour, after which the oil is run in
+again and is kept in the cylinders under 100 pounds pressure for from
+ten to twelve hours, until the required amount of absorption has been
+reached (about 12 pounds per cubic foot).
+
+
+                         Out-of-door Seasoning
+
+The most effective seasoning is without doubt that obtained by the
+uniform, slow drying which takes place in properly constructed piles
+outdoors, under exposure to the winds and the sun. Lumber has always
+been seasoned in this way, which is still the best for ordinary
+purposes.
+
+It is probable for the sake of economy, air-drying will be eliminated
+in the drying process of the future without loss to the quality of the
+product, but as yet no effective method has been discovered whereby
+this may be accomplished, because nature performs certain functions in
+air-drying that cannot be duplicated by artificial means. Because of
+this, hardwoods, as a rule, cannot be successfully kiln-dried green or
+direct from the saw, and must receive a certain amount of preliminary
+air-drying before being placed in a dry kiln.
+
+The present methods of air-seasoning in use have been determined by
+long experience, and are probably as good as they could be made for
+present conditions. But the same care has not up to this time been
+given to the seasoning of such timber as ties, bridge material, posts,
+telegraph and telephone poles, etc. These have sometimes been piled
+more or less intelligently, but in the majority of cases their value
+has been too low to make it seem worth while to pile with reference to
+anything beyond convenience in handling.
+
+In piling material for air-seasoning, one should utilize high, dry
+ground when possible, and see that the foundations are high enough off
+the ground, so that there is proper air circulation through the bottom
+of the piles, and also that the piles are far enough apart so that the
+air may circulate freely through and around them.
+
+It is air circulation that is desired in all cases of drying, both in
+dry kilns and out-of-doors, and not sunshine; that is, not the sun
+shining directly upon the material. The ends also should be protected
+from the sun, and everything possible done to induce a free
+circulation of air, and to keep the foundations free from all plant
+growth.
+
+Naturally, the heavier the material to be dried, the more difficulty
+is experienced from checking, which has its most active time in the
+spring when the sap is rising. In fact the main period of danger in
+material checking comes with the March winds and the April showers,
+and not infrequently in the South it occurs earlier than that. In
+other words, as soon as the sap begins to rise, the timber shows signs
+of checking, and that is the time to take extra precautions by careful
+piling and protection from the sun. When the hot days of summer arrive
+the tendency to check is not so bad, but stock will sour from the
+heat, stain from the sap, mildew from moisture, and fall a prey to
+wood-destroying insects.
+
+It has been proven in a general way that wood will season more slowly
+in winter than in summer, and also that the water content during
+various months varies. In the spring the drying-out of wood cut in
+October and November will take place more rapidly.
+
+
+
+
+                              SECTION XI
+
+                          KILN-DRYING OF WOOD
+
+
+               Advantages of Kiln-drying over Air-drying
+
+Some of the advantages of kiln-drying to be secured over air-drying in
+addition to reducing the shipping weight and lessening quantity of
+stock are the following:
+
+     1. Less material lost.
+     2. Better quality of product.
+     3. Prevention of sap stain and mould.
+     4. Fixation of gums and resins.
+     5. Reduction of hygroscopicity.
+
+This reduction in the tendency to take up moisture means a reduction
+in the "working" of the material which, even though slight, is of
+importance.
+
+The problem of drying wood in the best manner divides itself into two
+distinct parts, one of which is entirely concerned with the behavior
+of the wood itself and the physical phenomena involved, while the
+other part has to do with the control of the drying process.
+
+
+           Physical Conditions governing the Drying of Wood
+
+     1. Wood is soft and plastic while hot and moist, and becomes
+     "set" in whatever shape it dries. Some species are much more
+     plastic than others.
+
+     2. Wood substance begins to shrink only when it dries below
+     the fibre-saturation point, at which it contains from 25 to
+     30 per cent moisture based on its dry weight. Eucalyptus and
+     certain other species appear to be exceptions to this law.
+
+     3. The shrinkage of wood is about twice as great
+     circumferentially as in the radial direction; lengthwise, it
+     is very slight.
+
+     4. Wood shrinks most when subjected, while kept moist, to
+     slow drying at high temperatures.
+
+     5. Rapid drying produces less shrinkage than slow drying at
+     high temperatures, but is apt to cause case-hardening and
+     honeycombing, especially in dense woods.
+
+     6. Case-hardening, honeycombing, and cupping result directly
+     from conditions 1, 4, and 5, and chemical changes of the
+     outer surface.
+
+     7. Brittleness is caused by carrying the drying process too
+     far, or by using too high temperatures. Safe limits of
+     treatment vary greatly for different species.
+
+     8. Wood absorbs or loses moisture in proportion to the
+     relative humidity in the air, not according to the
+     temperature. This property is called its "hygroscopicity."
+
+     9. Hygroscopicity and "working" are reduced but not
+     eliminated by thorough drying.
+
+     10. Moisture tends to transfuse from the hot towards the
+     cold portion of the wood.
+
+     11. Collapse of the cells may occur in some species while
+     the wood is hot and plastic. This collapse is independent of
+     subsequent shrinkage.
+
+
+                         Theory of Kiln-drying
+
+The dry kiln has long since acquired particular appreciation at the
+hands of those who have witnessed its time-saving qualities, when
+practically applied to the drying of timber. The science of drying is
+itself of the simplest, the exposure to the air being, indeed, the
+only means needed where the matter of time is not called into
+question. Otherwise, where hours, even minutes, have a marked
+significance, then other means must be introduced to bring about the
+desired effect. In any event, however, the same simple and natural
+remedy pertains,--the absorption of moisture. This moisture in green
+timber is known as "sap", which is itself composed of a number of
+ingredients, most important among which are water, resin, and albumen.
+
+All dry kilns in existence use heat to season timber; that is, to
+drive out that portion of the "sap" which is volatile.
+
+The heat does not drive out the resin of the pines nor the albumen of
+the hardwoods. It is really of no advantage in this respect. Resin in
+its hardened state as produced by heat is only slowly soluble in water
+and contains a large proportion of carbon, the most stable form of
+matter. Therefore, its retention in the pores of the wood is a
+positive advantage.
+
+To produce the ideal effect the drying must commence at the heart of
+the piece and work outward, the moisture being removed from the
+surface as fast as it exudes from the pores of the wood. To
+successfully accomplish this, adjustments must be available to
+regulate the temperature, circulation, and humidity according to the
+variations of the atmospheric conditions, the kind and condition of
+the material to be dried.
+
+This ideal effect is only attained by the use of a type of dry kiln in
+which the surface of the lumber is kept soft, the pores being left
+open until all the moisture within has been volatilized by the heat
+and carried off by a free circulation of air. When the moisture has
+been removed from the pores, the surface is dried without closing the
+pores, resulting in timber that is clean, soft, bright, straight, and
+absolutely free from stains, checks, or other imperfections.
+
+Now, no matter how the method of drying may be applied, it must be
+remembered that vapor exists in the atmosphere at all times, its
+volume being regulated by the capacity of the temperature absorbed. To
+kiln-dry properly, a free current of air must be maintained, of
+sufficient volume to carry off this moisture. Now, the capacity of
+this air for drying depends entirely upon the ability of its
+temperature to absorb or carry off a larger proportion of moisture
+than that apportioned by natural means. Thus, it will be seen, a cubic
+foot of air at 32 degrees Fahrenheit is capable of absorbing only two
+grains of water, while at 160 degrees, it will dispose of ninety
+grains. The air, therefore, should be made as dry as possible and
+caused to move freely, so as to remove all moisture from the surface
+of the wood as soon as it appears. Thus the heat effects a double
+purpose, not only increasing the rate of evaporation, but also the
+capacity of the air for absorption. Where these means are applied,
+which rely on the heat alone to accomplish this purpose, only that of
+the moisture which is volatile succumbs, while the albumen and resin
+becoming hardened under the treatment close up the pores of the wood.
+This latter result is oft-times accomplished while moisture yet
+remains and which in an enforced effort to escape bursts open the
+cells in which it has been confined and creates what is known as
+"checks."
+
+Therefore, taking the above facts into consideration, the essentials
+for the successful kiln-drying of wood may be enumerated as follows:
+
+     1. The evaporation from the surface of a stick should not
+     exceed the rate at which the moisture transfuses from the
+     interior to the surface.
+
+     2. Drying should proceed uniformly at all points, otherwise
+     extra stresses are set up in the wood, causing warping, etc.
+
+     3. Heat should penetrate to the interior of the piece before
+     drying begins.
+
+     4. The humidity should be suited to the condition of the
+     wood at the start and reduced in the proper ratio as drying
+     progresses. With wet or green wood it should usually be held
+     uniform at a degree which will prevent the surface from
+     drying below its saturation point until all the free water
+     has evaporated, then gradually reduced to remove the
+     hygroscopic moisture.
+
+     5. The temperature should be uniform and as high as the
+     species under treatment will stand without excessive
+     shrinkage, collapse, or checking.
+
+     6. Rate of drying should be controlled by the amount of
+     humidity in the air and not by the rate of circulation,
+     which should be made ample at all times.
+
+     7. In drying refractory hardwoods, such as oak, best results
+     are obtained at a comparatively low temperature. In more
+     easily dried hardwoods, such as maple, and some of the more
+     difficult softwoods, as cypress, the process may be hastened
+     by a higher temperature but not above the boiling point. In
+     many of the softwoods, the rate of drying may be very
+     greatly increased by heating above the boiling point with a
+     large circulation of vapor at atmospheric pressure.
+
+     8. Unequal shrinkage between the exterior and interior
+     portions of the wood and also unequal chemical changes must
+     be guarded against by temperatures and humidities suited to
+     the species in question to prevent subsequent cupping and
+     warping.
+
+     9. The degree of dryness attained should conform to the use
+     to which the wood is put.
+
+     10. Proper piling of the material and weighting to prevent
+     warping are of great importance.
+
+
+                Requirements in a Satisfactory Dry Kiln
+
+The requirements in a satisfactory dry kiln are:
+
+     1. Control of humidity at all times.
+     2. Ample air circulation at all points.
+     3. Uniform and proper temperatures.
+
+In order to meet these requirements the United States Forestry Service
+has designed a kiln in which the humidity, temperature, and
+circulation can be controlled at all times.
+
+Briefly, it consists of a drying chamber with a partition on either
+side, making two narrow side chambers open top and bottom.
+
+The steam pipes are in the usual position underneath the material to
+be dried.
+
+At the top of the side chambers is a spray; at the bottom are gutters
+and an eliminator or set of baffle plates to separate the fine mist
+from the air.
+
+The spray accomplishes two things: It induces an increased circulation
+and it regulates the humidity. This is done by regulating the
+temperature of the spray water.
+
+The air under the heating coil is saturated at whatever temperature
+is required. This temperature is the dew point of the air after it
+passes up into the drying chamber above the coils. Knowing the
+temperature in the drying room and the dew point, the relative
+humidity is thus determined.
+
+The relative humidity is simply the ratio of the vapor pressure at the
+dew point to the pressure of saturated vapor (see Fig. 30).
+
+    [Illustration: Fig. 30. Section through United States
+    Forestry Service Humidity-controlled Dry Kiln.]
+
+
+          Theory and Description of the Forestry Service Kiln
+
+The humidities and temperatures in the piles of lumber are largely
+dependent upon the circulation of air within the kiln. The temperature
+and humidity within the kiln, taken alone, are no criterion of the
+conditions of drying the pile of lumber if the circulation in any
+portion is deficient. It is possible to have an extremely rapid
+circulation of air within the dry kiln itself and yet have stagnation
+within the individual piles, the air passing chiefly through open
+spaces and channels. Wherever stagnation exists or the movement of air
+is too sluggish the temperature will drop and the humidity increase,
+perhaps to the point of saturation.
+
+When in large kilns the forced circulation is in the opposite
+direction from that induced by the cooling of the air by the lumber,
+there is always more or less uncertainty as to the movement of the air
+through the piles. Even with the boards placed edge-wise, with
+stickers running vertically, and with the heating pipes beneath the
+lumber, it was found that although the air passed upward through most
+of the spaces it was actually descending through others, so that very
+unequal drying resulted. While edge piling would at first thought seem
+ideal for the freest circulation in an ordinary kiln with steam pipes
+below, it in fact produces an indeterminate condition; air columns may
+pass downward through some channels as well as upward through others,
+and probably stagnate in still others. Nevertheless, edge piling is
+greatly superior to flat piling where the heating system is below the
+lumber.
+
+From experiments and from study of conditions in commercial kilns the
+idea was developed of so arranging the parts of the kiln and the pile
+of lumber that advantage might be taken of this cooling of the air to
+assist the circulation. That this can be readily accomplished without
+doing away with the present features of regulation of humidity by
+means of a spray of water is clear from Fig. 30, which shows a
+cross-section of the improved humidity-regulated dry kiln.
+
+In the form shown in the sketch a chamber or flue B runs through the
+center near the bottom. This flue is only about 6 or 7 feet in height
+and, together with the water spray F and the baffle plates DD,
+constitutes the humidity-control feature of the kiln. This control of
+humidity is affected by the temperature of the water used in the
+spray. This spray completely saturates the air in the flue B at
+whatever predetermined temperature is required. The baffle plates DD
+are to separate all entrained particles of water from the air, so that
+it is delivered to the heaters in a saturated condition at the
+required temperature. This temperature is, therefore, the dew point of
+the air when heated above, and the method of humidity control may
+therefore be called the dew-point method. It is a very simple matter
+by means of the humidity diagram (see Fig. 93), or by a hygrodeik
+(Fig. 94), to determine what dew-point temperature is needed for any
+desired humidity above the heaters.
+
+Besides regulating the humidity the spray F also acts as an ejector
+and forces circulation of air through the flue B. The heating system H
+is concentrated near the outer walls, so as to heat the rising column
+of air. The temperature within the drying chamber is controlled by
+means of any suitable thermostat, actuating a valve on the main steam
+line. The lumber is piled in such a way that the stickers slope
+downward toward the sides of the kiln.
+
+M is an auxiliary steam spray pointing downward for use at very high
+temperatures. C is a gutter to catch the precipitation and conduct it
+back to the pump, the water being recirculated through the sprays. G
+is a pipe condenser for use toward the end of the drying operation. K
+is a baffle plate for diverting the heated air and at the same time
+shielding the under layers of boards from direct radiation of the
+steam pipes.
+
+The operation of the kiln is simple. The heated air rises above the
+pipes HH and between the piles of lumber. As it comes in contact with
+the piles, portions of it are cooled and pass downward and outward
+through the layers of boards into the space between the condensers GG.
+Here the column of cooled air descends into the spray flue B, where
+its velocity is increased by the force of the water spray. It then
+passes out from the baffle plates to the heaters and repeats the
+cycle.
+
+One of the greatest advantages of this natural circulation method is
+that the colder the lumber when placed in the kiln the greater is the
+movement produced, under the very conditions which call for the
+greatest circulation--just the opposite of the direct-circulation
+method. This is a feature of the greatest importance in winter, when
+the lumber is put into the kiln in a frozen condition. One truckload
+of lumber at 60 per cent moisture may easily contain over 7,000 pounds
+of ice.
+
+In the matter of circulation the kiln is, in fact, seldom
+regulatory--the colder the lumber the greater the circulation
+produced, with the effect increased toward the cooler and wetter
+portions of the pile.
+
+Preliminary steaming may be used in connection with this kiln, but
+experiments indicate that ordinarily it is not desirable, since the
+high humidity which can be secured gives as good results, and being at
+as low a temperature as desired, much better results in the case of
+certain difficult woods like oak, eucalyptus, etc., are obtained.
+
+This kiln has another advantage in that its operation is entirely
+independent of outdoor atmospheric conditions, except that barometric
+pressure will effect it slightly.
+
+
+                              KILN-DRYING
+
+                                Remarks
+
+Drying is an essential part of the preparation of wood for
+manufacture. For a long time the only drying process used or known was
+air-drying, or the exposure of wood to the gradual drying influences
+of the open air, and is what has now been termed "preliminary
+seasoning." This method is without doubt the most successful and
+effective seasoning, because nature performs certain functions in
+air-drying that cannot be duplicated by artificial means. Because of
+this, hardwoods, as a rule, cannot be successfully kiln-dried green or
+direct from the saw.
+
+Within recent years, considerable interest is awakening among wood
+users in the operation of kiln-drying. The losses occasioned in
+air-drying and in improper kiln-drying, and the necessity for getting
+material dry as quickly as possible from the saw, for shipping
+purposes and also for manufacturing, are bringing about a realization
+of the importance of a technical knowledge of the subject.
+
+The losses which occur in air-drying wood, through checking, warping,
+staining, and rotting, are often greater than one would suppose. While
+correct statistics of this nature are difficult to obtain, some idea
+may be had of the amount of degrading of the better class of lumber.
+In the case of one species of soft wood, Western larch, it is commonly
+admitted that the best grades fall off sixty to seventy per cent in
+air-drying, and it is probable that the same is true in the case of
+Southern swamp oaks. In Western yellow pine, the loss is great, and in
+the Southern red gum, it is probably as much as thirty per cent. It
+may be said that in all species there is some loss in air-drying, but
+in some easily dried species such as spruce, hemlock, maple, etc., it
+is not so great.
+
+It would hardly be correct to state at the present time that this loss
+could be entirely prevented by proper methods of kiln-drying the green
+lumber, but it is safe to say that it can be greatly reduced.
+
+It is well where stock is kiln-dried direct from the saw or knife,
+after having first been steamed or boiled--as in the case of veneers,
+etc.,--to get them into the kiln while they are still warm, as they
+are then in good condition for kiln-drying, as the fibres of the wood
+are soft and the pores well opened, which will allow of forcing the
+evaporation of moisture without much damage being done to the
+material.
+
+With softwoods it is a common practice to kiln-dry direct from the
+saw. This procedure, however, is ill adapted for the hardwoods, in
+which it would produce such warping and checking as would greatly
+reduce the value of the product. Therefore, hardwoods, as a rule, are
+more or less thoroughly air-dried before being placed in the dry kiln,
+where the residue of moisture may be reduced to within three or four
+per cent, which is much lower than is possible by air-drying only.
+
+It is probable that for the sake of economy, air-drying will be
+eliminated in the drying processes of the future without loss to the
+quality of the product, but as yet no method has been discovered
+whereby this may be accomplished.
+
+The dry kiln has been, and probably still is, one of the most
+troublesome factors arising from the development of the timber
+industry. In the earlier days, before power machinery for the
+working-up of timber products came into general use, dry kilns were
+unheard-of, air-drying or seasoning was then relied upon solely to
+furnish the craftsman with dry stock from which to manufacture his
+product. Even after machinery had made rapid and startling strides on
+its way to perfection, the dry kiln remained practically an unknown
+quantity, but gradually, as the industry developed and demand for dry
+material increased, the necessity for some more rapid and positive
+method of seasoning became apparent, and the subject of artificial
+drying began to receive the serious attention of the more progressive
+and energetic members of the craft.
+
+Kiln-drying which is an artificial method, originated in the effort to
+improve or shorten the process, by subjecting the wood to a high
+temperature or to a draught of heated air in a confined space or kiln.
+In so doing, time is saved and a certain degree of control over the
+drying operation is secured.
+
+The first efforts in the way of artificial drying were confined to
+aiding or hastening nature in the seasoning process by exposing the
+material to the direct heat from fires built in pits, over which the
+lumber was piled in a way to expose it to the heat rays of the fires
+below. This, of course, was a primitive, hazardous, and very
+unsatisfactory method, to say the least, but it marked the first step
+in the evolution of the present-day dry kiln, and in that particular
+only is it deserving of mention.
+
+
+                         Underlying Principles
+
+In addition to marking the first step in artificial drying, it
+illustrated also, in the simplest manner possible, the three
+underlying principles governing all drying problems: (1) The
+application of heat to evaporate or volatilize the water contained in
+the material; (2) with sufficient air in circulation to carry away in
+suspension the vapor thus liberated; and (3) with a certain amount of
+humidity present to prevent the surface from drying too rapidly while
+the heat is allowed to penetrate to the interior. The last performs
+two distinct functions: (a) It makes the wood more permeable to the
+passage of the moisture from the interior of the wood to the surface,
+and (b) it supplies the latent heat necessary to evaporate the
+moisture after it reaches the surface. The air circulation is
+important in removing the moisture after it has been evaporated by the
+heat, and ventilation also serves the purpose of bringing the heat in
+contact with the wood. If, however, plain, dry heat is applied to the
+wood, the surface will become entirely dry before the interior
+moisture is even heated, let alone removed. This condition causes
+"case-hardening" or "hollow-horning." So it is very essential that
+sufficient humidity be maintained to prevent the surface from drying
+too rapidly, while the heat is allowed to penetrate to the interior.
+
+This humidity or moisture is originated by the evaporation from the
+drying wood, or by the admission of steam into the dry kiln by the use
+of steam spray pipes, and is absolutely necessary in the process of
+hastening the drying of wood. With green lumber it keeps the sap near
+the surface of the piece in a condition that allows the escape of the
+moisture from its interior; or, in other words, it prevents the
+outside from drying first, which would close the pores and cause
+case-hardening.
+
+The great amount of latent heat necessary to evaporate the water after
+it has reached the surface is shown by the fact that the evaporation
+of only one pound of water will extract approximately 66 degrees from
+1,000 cubic feet of air, allowing the air to drop in temperature from
+154 to 84 degrees Fahrenheit. In addition to this amount of heat, the
+wood and the water must also be raised to the temperature at which the
+drying is to be accomplished.
+
+It matters not what type of dry kiln is used, source or application of
+heating medium, these underlying principles remain the same, and must
+be the first things considered in the design or selection of the
+equipment necessary for producing the three essentials of drying:
+Heat, humidity, and circulation.
+
+Although these principles constitute the basis of all drying problems
+and must, therefore, be continually carried in mind in the
+consideration of them, it is equally necessary to have a comprehensive
+understanding of the characteristics of the materials to be dried, and
+its action during the drying process. All failures in the past, in the
+drying of timber products, can be directly attributed to either the
+kiln designer's neglect of these things, or his failure to carry them
+fully in mind in the consideration of his problems.
+
+Wood has characteristics very much different from those of other
+materials, and what little knowledge we have of it and its properties
+has been taken from the accumulated records of experience. The reason
+for this imperfect knowledge lies in the fact that wood is not a
+homogeneous material like the metals, but a complicated structure, and
+so variable that one stick will behave in a manner widely different
+from that of another, although it may have been cut from the same
+tree.
+
+The great variety of woods often makes the mere distinction of the
+kind or species of the tree most difficult. It is not uncommon to find
+men of long experience disagree as to the kind of tree a certain piece
+of lumber was cut from, and, in some cases, there is even a wide
+difference in the appearance and evidently the structure of timber cut
+from the same tree.
+
+
+                        Objects of Kiln-drying
+
+The objects of kiln-drying wood may be placed under three main
+headings: (1) To reduce shipping expenses; (2) to reduce the quantity
+necessary to maintain in stock; and (3) to reduce losses in air-drying
+and to properly prepare the wood for subsequent use. Item number 2
+naturally follows as a consequence of either 1 or 3. The reduction in
+weight on account of shipping expenses is of greatest significance
+with the Northwestern lumbermen in the case of Douglas fir, redwood,
+Western red cedar, sugar pine, bull pine, and other softwoods.
+
+Very rapid methods of rough drying are possible with some of these
+species, and are in use. High temperatures are used, and the water is
+sometimes boiled off from the wood by heating above 212 degrees
+Fahrenheit. These high-temperature methods will not apply to the
+majority of hardwoods, however, nor to many of the softwoods.
+
+It must first of all be recognized that the drying of lumber is a
+totally different operation from the drying of a fabric or of thin
+material. In the latter, it is largely a matter of evaporated
+moisture, but wood is not only hygroscopic and attracts moisture from
+the air, but its physical behavior is very complex and renders the
+extraction of moisture a very complicated process.
+
+An idea of its complexity may be had by mentioning some of the
+conditions which must be contended with. Shrinkage is, perhaps, the
+most important. This is unequal in different directions, being twice
+as great tangentially as radially and fifty times as great radially as
+longitudinally. Moreover, shrinkage is often unequal in different
+portions of the same piece. The slowness of the transfusion of
+moisture through the wood is an important factor. This varies with
+different woods and greatly in different directions. Wood becomes soft
+and plastic when hot and moist, and will yield more or less to
+internal stresses. As some species are practically impervious to air
+when wet, this plasticity of the cell walls causes them to collapse as
+the water passes outward from the cell cavities. This difficulty has
+given much trouble in the case of Western red cedar, and also to some
+extent in redwood. The unequal shrinkage causes internal stresses in
+the wood as it dries, which results in warping, checking,
+case-hardening, and honeycombing. Case-hardening is one of the most
+common defects in improperly dried lumber. It is clearly shown by the
+cupping of the two halves when a case-hardened board is resawed.
+Chemical changes also occur in the wood in drying, especially so at
+higher temperatures, rendering it less hygroscopic, but more brittle.
+If dried too much or at too high a temperature, the strength and
+toughness is seriously reduced.
+
+
+                         Conditions of Success
+
+Commercial success in drying therefore requires that the substance be
+exposed to the air in the most efficient manner; that the temperature
+of the air be as high as the substance will stand without injury, and
+that the air change or movement be as rapid as is consistent with
+economical installation and operation. Conditions of success therefore
+require the observance of the following points, which embody the basic
+principles of the process: (1) The timber should be heated through
+before drying begins. (2) The air should be very humid at the
+beginning of the drying process, and be made drier only gradually. (3)
+The temperature of the lumber must be maintained uniformly throughout
+the entire pile. (4) Control of the drying process at any given
+temperature must be secured by controlling the relative humidity, not
+by decreasing the circulation. (5) In general, high temperatures
+permit more rapid drying than do lower temperatures. The higher the
+temperature of the lumber, the more efficient is the kiln. It is
+believed that temperatures as high as the boiling point are not
+injurious to most woods, providing all other fundamentally important
+features are taken care of. Some species, however, are not able to
+stand as high temperatures as others, and (6) the degree of dryness
+attained, where strength is the prime requisite, should not exceed
+that at which the wood is to be used.
+
+
+                 Different Treatment according to Kind
+
+The rapidity with which water may be evaporated, that is, the rate of
+drying, depends on the size and shape of the piece and on the
+structure of the wood. Thin stock can be dried much faster than thick,
+under the same conditions of temperature, circulation, and humidity.
+Pine can be dried, as a general thing, in about one third of the time
+that would be required for oak of the same thickness, although the
+former contains the more water of the two. Quarter-sawn oak usually
+requires half again as long as plain oak. Mahogany requires about the
+same time as plain oak; ash dries in a little less time, and maple,
+according to the purpose for which it is intended, may be dried in one
+fifth the time needed for oak, or may require a slightly longer
+treatment. For birch, the time required is from one half to two
+thirds, and for poplar and basswood, from, one fifth to one third that
+required for oak.
+
+All kinds and thicknesses of lumber cannot be dried at the same time
+in the same kiln. It is manifest that green and air-dried lumber,
+dense and porous lumber, all require different treatment. For
+instance, Southern yellow pine when cut green from the log will stand
+a very high temperature, say 200 degrees Fahrenheit, and in fact this
+high temperature is necessary together with a rapid circulation of air
+in order to neutralize the acidity of the pitch which causes the wood
+to blue and discolor. This lumber requires to be heated up immediately
+and to be kept hot throughout the length of the kiln. Hence the kiln
+must not be of such length as to allow of the air being too much
+cooled before escaping.
+
+
+                          Temperature depends
+
+While it is true that a higher temperature can be carried in the kiln
+for drying pine and similar woods, this does not altogether account
+for the great difference in drying time, as experience has taught us
+that even when both woods are dried in the same kiln, under the same
+conditions, pine will still dry much faster, proving thereby that the
+structure of the wood itself affects drying.
+
+The aim of all kiln designers should be to dry in the shortest
+possible time, without injury to the material. Experience has
+demonstrated that high temperatures are very effective in evaporating
+water, regardless of the degree of humidity, but great care must be
+exercised in using extreme temperatures that the material to be dried
+is not damaged by checking, case-hardening, or hollow-horning.
+
+The temperature used should depend upon the species and condition of
+the material when entering the kiln. In general, it is advantageous to
+have as high a temperature as possible, both for economy of operation
+and speed of drying, but the physical properties of the wood will
+govern this.
+
+Many species cannot be dried satisfactorily at high temperatures on
+account of their peculiar behavior. This is particularly so with green
+lumber.
+
+Air-dried wood will stand a relatively higher temperature, as a rule,
+than wet or green wood. In drying green wood direct from the saw, it
+is usually best to start with a comparatively low temperature, and not
+raise the temperature until the wood is nearly dry. For example, green
+maple containing about 60 per cent of its dry weight in water should
+be started at about 120 degrees Fahrenheit and when it reaches a
+dryness of 25 per cent, the temperature may be raised gradually up to
+190 degrees.
+
+It is exceedingly important that the material be practically at the
+same temperature throughout if perfect drying is to be secured. It
+should be the same temperature in the center of a pile or car as on
+the outside, and the same in the center of each individual piece of
+wood as on its surface. This is the effect obtained by natural
+air-drying. The outside atmosphere and breezes (natural air
+circulation) are so ample that the heat extracted for drying does not
+appreciably change the temperature.
+
+When once the wood has been raised to a high temperature through and
+through and especially when the surface has been rendered most
+permeable to moisture, drying may proceed as rapidly as it can be
+forced by artificial circulation, provided the heat lost from the wood
+through vaporization is constantly replaced by the heat of the kiln.
+
+It is evident that to secure an even temperature, a free circulation
+of air must be brought in contact with the wood. It is also evident
+that in addition to heat and a circulation of air, the air must be
+charged with a certain amount of moisture to prevent surface drying or
+case-hardening.
+
+There are some twenty-five different makes of dry kilns on the market,
+which fulfill to a varying degree the fundamental requirements.
+Probably none of them succeed perfectly in fulfilling all.
+
+It is well to have the temperature of a dry kiln controlled by a
+thermostat which actuates the valve on the main steam supply pipe. It
+is doubly important to maintain a uniform temperature and avoid
+fluctuations in the dry kiln, since a change in temperature will
+greatly alter the relative humidity.
+
+In artificial drying, temperatures of from 150 to 180 degrees
+Fahrenheit are usually employed. Pine, spruce, cypress, cedar, etc.,
+are dried fresh from the saw, allowing four days for 1-inch stuff.
+Hardwoods, especially oak, ash, maple, birch, sycamore, etc., are
+usually air-seasoned for three to six months to allow the first
+shrinkage to take place more gradually, and are then exposed to the
+above temperatures in the kiln for about six to ten days for 1-inch
+stuff, other dimensions in proportion.
+
+Freshly cut poplar and cottonwood are often dried direct from the saw
+in a kiln. By employing lower temperatures, 100 to 120 degrees
+Fahrenheit, green oak, ash, etc., can be seasoned in dry kilns without
+much injury to the material.
+
+Steaming and sweating the wood is sometimes resorted to in order to
+prevent checking and case-hardening, but not, as has been frequently
+asserted, to enable the material to dry.
+
+
+                            Air Circulation
+
+Air circulation is of the utmost importance, since no drying whatever
+can take place when it is lacking. The evaporation of moisture
+requires heat and this must be supplied by the circulating air.
+Moreover, the moisture laden air must be constantly removed and fresh,
+drier air substituted. Probably this is the factor which gives more
+trouble in commercial operations than anything else, and the one which
+causes the greatest number of failures.
+
+It is necessary that the air circulate through every part of the kiln
+and that the moving air come in contact with every portion of the
+material to be dried. In fact, the humidity is dependent upon the
+circulation. If the air stagnates in any portion of the pile, then the
+temperature will drop and the humidity rise to a condition of
+saturation. Drying will not take place at this portion of the pile and
+the material is apt to mould and rot.
+
+The method of piling the material on trucks or in the kiln, is
+therefore, of extreme importance. Various methods are in use. Ordinary
+flat piling is probably the poorest. Flat piling with open chimney
+spaces in the piles is better. But neither method is suitable for a
+kiln in which the circulation is mainly vertical.
+
+Edge piling with stickers running vertically is in use in kilns when
+the heating coils are beneath. This is much better.
+
+Air being cooled as it comes in contact with a pile of material,
+becomes denser, and consequently tends to sink. Unless the material to
+be dried is so arranged that the air can pass gradually downward
+through the pile as it cools, poor circulation is apt to result.
+
+In edge-piled lumber, with the heating system beneath the piles, the
+natural tendency of the cooled air to descend is opposed by the hot
+air beneath which tends to rise. An indeterminate condition is thus
+brought about, resulting in non-uniform drying. It has been found that
+air will rise through some layers and descend through others.
+
+
+                               Humidity
+
+Humidity is of prime importance because the rate of drying and
+prevention of checking and case-hardening are largely dependent
+thereon. It is generally true that the surface of the wood should not
+dry more rapidly than the moisture transfuses from the center of the
+piece to its surface, otherwise disaster will result. As a sufficient
+amount of moisture is removed from the wood to maintain the desired
+humidity, it is not good economy to generate moisture in an outside
+apparatus and force it into a kiln, unless the moisture in the wood is
+not sufficient for this purpose; in that case provision should be made
+for adding any additional moisture that may be required.
+
+The rate of evaporation may best be controlled by controlling the
+amount of vapor present in the air (relative humidity); it should not
+be controlled by reducing the air circulation, since a large
+circulation is needed at all times to supply the necessary heat.
+
+The humidity should be graded from 100 per cent at the receiving end
+of the kiln, to whatever humidity corresponds with the desired degree
+of dryness at the delivery end.
+
+The kiln should be so designed that the proper degree may be
+maintained at its every section.
+
+A fresh piece of sapwood will lose weight in boiling water and can
+also be dried to quite an extent in steam. This proves conclusively
+that a high degree of humidity does not have the detrimental effect on
+drying that is commonly attributed to it. In fact, a proper degree of
+humidity, especially in the loading or receiving end of a kiln, is
+just as necessary to good results in drying as getting the proper
+temperature.
+
+Experiments have demonstrated also that injury to stock in the way of
+checking, warping, and hollow-horning always develops immediately
+after the stock is taken into the kiln, and is due to the degree of
+humidity being too low. The receiving end of the kiln should always be
+kept moist, where the stock has not been steamed before being put into
+the kiln. The reason for this is simple enough. When the air is too
+dry it tends to dry the outside of the material first--which is termed
+"case-hardening"--and in so doing shrinks and closes up the pores of
+the wood. As the stock is moved down the kiln, it absorbs a
+continually increasing amount of heat, which tends to drive off the
+moisture still present in the center of the stock. The pores on the
+outside having been closed up, there is no exit for the vapor or steam
+that is being rapidly formed in the center. It must find its way out
+some way, and in doing so sets up strains, which result either in
+checking, warping, or hollow-horning. If the humidity had been kept
+higher, the outside of the material would not have dried so quickly,
+and the pores would have remained open for the exit of moisture from
+the interior of the wood, and this trouble would have been avoided.
+
+Where the humidity is kept at a high point in the receiving end of the
+kiln, a higher rate of temperature may also be carried, and in that
+way the drying process is hastened with comparative safety.
+
+It is essential, therefore, to have an ample supply of heat through
+the convection currents of the air; but in the case of wood the rate
+of evaporation must be controlled, else checking will occur. This can
+be done by means of the relative humidity, as stated before. It is
+clear now that when the air--or, more properly speaking, the space--is
+completely saturated no evaporation can take place at the given
+temperature. By reducing the humidity, evaporation takes place more
+and more rapidly.
+
+Another bad feature of an insufficient and non-uniform supply of heat
+is that each piece of wood will be heated to the evaporating point on
+the outer surface, the inside remaining cool until considerable drying
+has taken place from the surface. Ordinarily in dry kilns high
+humidity and large circulation of air are antitheses to one another.
+To obtain the high humidity the circulation is either stopped
+altogether or greatly reduced, and to reduce the humidity a greater
+circulation is induced by opening the ventilators or otherwise
+increasing the draft. This is evidently not good practice, but as a
+rule is unavoidable in most dry kilns of present make. The humidity
+should be raised to check evaporation without reducing the circulation
+if possible.
+
+While thin stock, such as cooperage and box stuff is less inclined to
+give trouble by undue checking than 1-inch and thicker, one will find
+that any dry kiln will give more uniform results and, at the same
+time, be more economical in the use of steam, when the humidity and
+temperature is carried at as high a point as possible without injury
+to the material to be dried.
+
+Any well-made dry kiln which will fulfill the conditions required as
+to circulation and humidity control should work satisfactorily; but
+each case must be studied by itself, and the various factors modified
+to suit the peculiar conditions of the problem in hand. In every new
+case the material should be constantly watched and studied and, if
+checking begins, the humidity should be increased until it stops. It
+is not reducing the circulation, but adding the necessary moisture to
+the air, that should be depended on to prevent checking. For this
+purpose it is well to have steam jets in the kiln so that if needed
+they are ready at hand.
+
+
+                              Kiln-drying
+
+There are two distinct ways of handling material in dry kilns. One way
+is to place the load of lumber in a chamber where it remains in the
+same place throughout the operation, while the conditions of the
+drying medium are varied as the drying progresses. This is the
+"apartment" kiln or stationary method. The other is to run the lumber
+in at one end of the chamber on a wheeled truck and gradually move it
+along until the drying process is completed, when it is taken out at
+the opposite end of the kiln. It is the usual custom in these kilns to
+maintain one end of the chamber moist and the other end dry. This is
+known as the "progressive" type of kiln, and is the one most commonly
+used in large operations.
+
+It is, however, the least satisfactory of the two where careful drying
+is required, since the conditions cannot be so well regulated and the
+temperatures and humidities are apt to change with any change of wind.
+The apartment method can be arranged so that it will not require any
+more kiln space or any more handling of lumber than the progressive
+type. It does, however, require more intelligent operation, since the
+conditions in the drying chamber must be changed as the drying
+progresses. With the progressive type the conditions, once properly
+established, remain the same.
+
+To obtain draft or circulation three methods are in use--by forced
+draft or a blower usually placed outside the kiln, by ventilation, and
+by internal circulation and condensation. A great many patents have
+been taken out on different methods of ventilation, but in actual
+operation few kilns work exactly as intended. Frequently the air moves
+in the reverse direction for which the ventilators were planned.
+Sometimes a condenser is used in connection with the blower and the
+air is recirculated. It is also--and more satisfactorily--used with
+the gentle internal-gravity currents of air.
+
+Many patents have been taken out for heating systems. The differences
+among these, however, have more to do the mechanical construction than
+with the process of drying. In general, the heating is either direct
+or indirect. In the former steam coils are placed in the chamber with
+the lumber, and in the latter the air is heated by either steam coils
+or a furnace before it is introduced into the drying chamber.
+
+Moisture is sometimes supplied by means of free steam jets in the kiln
+or in the entering air; but more often the moisture evaporated from
+the lumber is relied upon to maintain the humidity necessary.
+
+A substance becomes dry by the evaporation of its inherent moisture
+into the surrounding space. If this space be confined it soon becomes
+saturated and the process stops. Hence, constant change is necessary
+in order that the moisture given off may be continually carried away.
+
+In practice, air movement, is therefore absolutely essential to the
+process of drying. Heat is merely a useful accessory which serves to
+decrease the time of drying by increasing both the rate of evaporation
+and the absorbing power of the surrounding space.
+
+It makes no difference whether this space is a vacuum or filled with
+air; under either condition it will take up a stated weight of vapor.
+From this it appears that the vapor molecules find sufficient space
+between the molecules of air. But the converse is not true, for
+somewhat less air will be contained in a given space saturated with
+vapor than in one devoid of moisture. In other words the air does not
+seem to find sufficient space between the molecules of vapor.
+
+If the temperature of the confined space be increased, opportunity
+will thereby be provided for the vaporization of more water, but if it
+be decreased, its capacity for moisture will be reduced and visible
+water will be deposited. The temperature at which this takes place is
+known as the "dew-point" and depends upon the initial degree of
+saturation of the given space; the less the relative saturation the
+lower the dew-point.
+
+Careful piling of the material to be dried, both in the yard and dry
+kiln, is essential to good results in drying.
+
+Air-dried material is not dry, and its moisture is too unevenly
+distributed to insure good behavior after manufacture.
+
+It is quite a difficult matter to give specific or absolute correct
+weights of any species of timber when thoroughly or properly dried, in
+order that one may be guided in these kiln operations, as a great deal
+depends upon the species of wood to be dried, its density, and upon
+the thickness which it has been cut, and its condition when entering
+the drying chamber.
+
+Elm will naturally weigh less than beech, and where the wood is
+close-grained or compact it will weigh more than coarse-grained wood
+of the same species, and, therefore, no set rules can be laid down, as
+good judgment only should be used, as the quality of the drying is not
+purely one of time. Sometimes the comparatively slow process gives
+excellent results, while to rush a lot of stock through the kiln may
+be to turn it out so poorly seasoned that it will not give
+satisfaction when worked into the finished product. The mistreatment
+of the material in this respect results in numerous defects, chief
+among which are warping and twisting, checking, case-hardening, and
+honeycombing, or, as sometimes called, hollow-horning.
+
+Since the proportion of sap and heartwood varies with size, age,
+species, and individual trees, the following figures as regards weight
+must be regarded as mere approximations:
+
+
+  POUNDS OF WATER LOST IN DRYING 100 POUNDS OF GREEN WOOD IN THE KILN
+
+=========================================================================
+                                                |Sapwood or | Heartwood
+                                                |outer part | or interior
+=========================================================================
+                                                |           |
+(1) Pine, cedar, spruce, and fir                |  45-65    |   16-25
+(2) Cypress, extremely variable                 |  50-65    |   18-60
+(3) Poplar, cottonwood, and basswood            |  60-65    |   40-60
+(4) Oak, beech, ash, maple, birch, elm, hickory,|           |
+    chestnut, walnut, and sycamore              |  40-50    |   30-40
+=========================================================================
+
+The lighter kinds have the most water in the sapwood; thus sycamore
+has more water than hickory, etc.
+
+The efficiency of the drying operations depends a great deal upon the
+way in which, the lumber is piled, especially when the humidity is not
+regulated. From the theory of drying it is evident that the rate of
+evaporation in dry kilns where the humidity is not regulated depends
+entirely upon the rate of circulation, other things being equal.
+Consequently, those portions of the wood which receive the greatest
+amount of air dry the most rapidly, and vice versa. The only way,
+therefore, in which anything like uniform drying can take place is
+where the lumber is so piled that each portion of it comes in contact
+with the same amount of air.
+
+In the Forestry Service kiln (Fig. 30), where the degree of relative
+humidity is used to control the rate of drying, the amount of
+circulation makes little difference, provided it exceeds a certain
+amount. It is desirable to pile the lumber so as to offer as little
+frictional resistance as possible and at the same time secure uniform
+circulation. If circulation is excessive in any place it simply means
+waste of energy but no other injury to the lumber.
+
+The best method of piling is one which permits the heated air to pass
+through the pile in a somewhat downward direction. The natural
+tendency of the cooled air to descend is thus taken advantage of in
+assisting the circulation in the kiln. This is especially important
+when cold or green lumber is first introduced into the kiln. But even
+when the lumber has become warmed the cooling due to the evaporation
+increases the density of the mixture of the air and vapor.
+
+
+                            Kiln-drying Gum
+
+The following article was published by the United States Forestry
+Service as to the best method of kiln-drying gum:
+
+=Piling.=--Perhaps the most important factor in good kiln-drying,
+especially in the case of the gums, is the method of piling. It is our
+opinion that proper and very careful piling will greatly reduce the
+loss due to warping. A good method of piling is to place the lumber
+lengthwise of the kiln and on an incline cross-wise. The warm air
+should rise at the higher side of the pile and descend between the
+courses of lumber. The reason for this is very simple and the
+principle has been applied in the manufacture of the best ice boxes
+for some time. The most efficient refrigerators are iced at the side,
+the ice compartment opening to the cooling chamber at the top and
+bottom. The warm air from above is cooled by melting the ice. It then
+becomes denser and settles down into the main chamber. The articles in
+the cooling room warm the air as they cool, so it rises to the top and
+again comes in contact with the ice, thus completing the cycle. The
+rate of this natural circulation is automatically regulated by the
+temperature of the articles in the cooling chamber and by the amount
+of ice in the icing compartment; hence the efficiency of such a box is
+high.
+
+Now let us apply this principle to the drying of lumber. First we must
+understand that as long as the lumber is moist and drying, it will
+always be cooler than the surrounding air, the amount of this
+difference being determined by the rate of drying and the moisture in
+the wood. As the lumber dries, its temperature gradually rises until
+it is equal to that of the air, when perfect dryness results. With
+this fact in mind it is clear that the function of the lumber in a
+kiln is exactly analogous to that of the ice in an ice box; that is,
+it is the cooling agent. Similarly, the heating pipes in a dry kiln
+bring about the same effect as the articles of food in the ice box in
+that they serve to heat the air. Therefore, the air will be cooled by
+the lumber, causing it to pass downward through the piles. If the
+heating units are placed at the sides of the kiln, the action of the
+air in a good ice box is duplicated in the kiln. The significant point
+in this connection is that, the greener and colder the lumber, the
+faster is the circulation. This is a highly desirable feature.
+
+A second vital point is that as the wood becomes gradually drier the
+circulation automatically decreases, thus resulting in increased
+efficiency, because there is no need for circulation greater than
+enough to maintain the humidity of the air as it leaves the lumber
+about the same as it enters. Therefore, we advocate either the
+longitudinal side-wise inclined pile or edge stacking, the latter
+being much preferable when possible. Of course the piles in our kiln
+were small and could not be weighted properly, so the best results as
+to reducing warping were not obtained.
+
+=Preliminary Steaming.=--Because the fibres of the gums become plastic
+while moist and hot without causing defects, it is desirable to heat
+the air-dried lumber to about 200 degrees Fahrenheit in saturated
+steam at atmospheric pressure in order to reduce the warping. This
+treatment also furnishes a means of heating the lumber very rapidly.
+It is probably a good way to stop the sap-staining of green lumber, if
+it is steamed while green. We have not investigated the other effects
+of steaming green gum, however, so we hesitate to recommend it.
+
+Temperatures as high as 210 degrees Fahrenheit were used with no
+apparent harm to the material. The best result was obtained with the
+temperature of 180 degrees Fahrenheit, after the first preliminary
+heating in steam to 200 degrees Fahrenheit. Higher temperatures may be
+used with air-dried gum, however.
+
+The best method of humidity control proved to be to reduce the
+relative humidity of the air from 100 per cent (saturated steam) very
+carefully at first and then more rapidly to 30 per cent in about four
+days. If the change is too marked immediately after the steaming
+period, checking will invariably result. Under these temperature and
+humidity conditions the stock was dried from 15 per cent moisture,
+based on the dry wood weight, to 6 per cent in five days' time. The
+loss due to checking was about 5 per cent, based on the actual footage
+loss, not on commercial grades.
+
+=Final Steaming.=--From time to time during the test runs the material
+was resawed to test for case-hardening. The stock dried in five days
+showed slight case-hardening, so it was steamed at atmospheric
+pressure for 36 minutes near the close of the run, with the result
+that when dried off again the stresses were no longer present. The
+material from one run was steamed for three hours at atmospheric
+pressure and proved very badly case-hardened, but in the reverse
+direction. It seems possible that by testing for the amount of
+case-hardening one might select a final steaming period which would
+eliminate all stresses in the wood.
+
+
+                     Kiln-drying of Green Red Gum
+
+The following article was published by the United States Forestry
+Service on the kiln-drying of green red gum:
+
+A short time ago fifteen fine, red-gum logs 16 feet long were received
+from Sardis, Miss. They were in excellent condition and quite green.
+
+It has been our belief that if the gum could be kiln-dried directly
+from the saw, a number of the difficulties in seasoning might be
+avoided. Therefore, we have undertaken to find out whether or not such
+a thing is feasible. The green logs now at the laboratory are to be
+used in this investigation. One run of a preliminary nature has just
+been made, the method and results of which I will now tell.
+
+This method was really adapted to the drying of Southern pine, and one
+log of the green gum was cut into 1-inch stock and dried with the
+pine. The heartwood contained many knots and some checks, although it
+was in general of quite good quality. The sapwood was in fine
+condition and almost as white as snow.
+
+This material was edge-stacked with one crosser at either end and one
+at the center, of the 16-foot board. This is sufficient for the pine,
+but was absolutely inadequate for drying green gum. A special
+shrinkage take-up was applied at the three points. The results proved
+very interesting in spite of the warping which was expected with but
+three crossers in 16 feet. The method of circulation described was
+used. It is our belief that edge piling is best for this method.
+
+This method of kiln-drying depends on the maintenance of a high
+velocity of slightly superheated steam through the lumber. In few
+words, the object is to maintain the temperature of the vapor as it
+leaves the lumber at slightly above 212 degrees Fahrenheit. In order
+to accomplish this result, it is necessary to maintain the high
+velocity of circulation. As the wood dries, the superheat may be
+increased until a temperature of 225 degrees or 230 degrees Fahrenheit
+of the exit air is recorded.
+
+The 1-inch green gum was dried from 20.1 per cent to 11.4 per cent
+moisture, based on the dry wood weight in 45 hours. The loss due to
+checking was 10 per cent. Nearly every knot in the heartwood was
+checked, showing that as the knots could be eliminated in any case,
+this loss might not be so great. It was significant that practically
+all of the checking occurred in the heartwood. The loss due to warping
+was 22 per cent. Of course this was large; but not nearly enough
+crossers were used for the gum. It is our opinion that this loss due
+to warping can be very much reduced by using at least eight crossers
+and providing for taking up of the shrinkage. A feature of this
+process which is very important is that the method absolutely prevents
+all sap staining.
+
+Another delightful surprise was the manner in which the superheated
+steam method of drying changed the color of the sapwood from pure
+white to a beautifully uniform, clean-looking, cherry red color which
+very closely resembles that of the heartwood. This method is not new
+by any means, as several patents have been granted on the steaming of
+gum to render the sapwood more nearly the color of the heartwoods. The
+method of application in kiln-drying green gum we believe to be new,
+however. Other methods for kiln-drying this green stock are to be
+tested until the proper process is developed. We expect to have
+something interesting to report in the near future.[1]
+
+    [Footnote 1: The above test was made at the United States
+    Forestry Service Laboratory, Madison, Wis.]
+
+
+
+
+                              SECTION XII
+
+                          TYPES OF DRY KILNS
+
+                     DIFFERENT TYPES OF DRY KILNS
+
+
+Dry kilns as in use to-day are divided into two classes: The "pipe" or
+"moist-air" kiln, in which natural draft is relied upon for
+circulation and, the "blower" or "hot blast" kiln, in which the
+circulation is produced by fans or blowers. Both classes have their
+adherents and either one will produce satisfactory results if properly
+operated.
+
+
+                   The "Blower" or "Hot Blast" Kiln
+
+The blower kiln in its various types has been in use so long that it
+is hardly necessary to give to it a lengthy introduction. These kilns
+at their inauguration were a wonderful improvement over the old style
+"bake-oven" or "sweat box" kiln then employed, both on account of the
+improved quality of the material and the rapidity at which it was
+dried.
+
+These blower kilns have undergone steady improvement, not only in the
+apparatus and equipment, but also in their general design, method of
+introducing air, and provision for controlling the temperature and
+humidity. With this type of kiln the circulation is always under
+absolute control and can be adjusted to suit the conditions, which
+necessarily vary with the conditions of the material to be dried and
+the quantity to be put through the kiln.
+
+In either the blower or moist-air type of dry kiln, however, it is
+absolutely essential, in order to secure satisfactory results, both as
+to rapidity in drying and good quality of stock, that the kiln be so
+designed that the temperature and humidity, together with circulation,
+are always under convenient control. Any dry kiln in which this has
+not been carefully considered will not give the desired results.
+
+In the old style blower kiln, while the circulation and temperature
+was very largely under the operator's control, it was next to
+impossible to produce conditions in the receiving end of the kiln so
+that the humidity could be kept at the proper point. In fact, this was
+one reason why the natural draft, or so-called moist-air kiln was
+developed.
+
+The advent of the moist-air kiln served as an education to kiln
+designers and manufacturers, in that it has shown conclusively the
+value of a proper degree of humidity in the receiving end of any
+progressive dry kiln, and it has been of special benefit also in that
+it gave the manufacturers of blower kilns an idea as to how to improve
+the design of their type of kiln to overcome the difficulty referred
+to in the old style blower kilns. This has now been remedied, and in a
+decidedly simple manner, as is usually the case with all things that
+possess merit.
+
+It was found that by returning from one third to one half of the moist
+air _after_ having passed through the kiln back to the fan room and by
+mixing it with the fresh and more or less dry air going into the
+drying room, that the humidity could be kept under convenient control.
+
+The amount of air that can be returned from a kiln of this class
+depends upon three things: (1) The condition of the material when
+entering the drying room; (2) the rapidity with which the material is
+to be dried; and (3) the condition of the outside atmosphere. In the
+winter season it will be found that a larger proportion of air may be
+returned to the drying room than in summer, as the air during the
+winter season contains considerably less moisture and as a consequence
+is much drier. This is rather a fortunate coincidence, as, when the
+kiln is being operated in this manner, it will be much more economical
+in its steam consumption.
+
+In the summer season, when the outside atmosphere is saturated to a
+much greater extent, it will be found that it is not possible to
+return as great a quantity of air to the drying room, although there
+have been instances of kilns of this class, which in operation have
+had all the air returned and found to give satisfactory results. This
+is an unusual condition, however, and can only be accounted for by
+some special or peculiar condition surrounding the installation.
+
+In some instances, the desired amount of humidity in a blower type of
+kiln is obtained by the addition of a steam spray in the receiving end
+of the kiln, much in the same manner as that used in the moist-air
+kilns. This method is not as economical as returning the
+moisture-laden air from the drying room as explained in the preceding
+paragraph.
+
+With the positive circulation that may be obtained in a blower kiln,
+and with the conditions of temperature and humidity under convenient
+control, this type of kiln has the elements most necessary to produce
+satisfactory drying in the quickest possible elapsed time.
+
+It must not be inferred from this, however, that this class of dry
+kiln may be installed and satisfactory results obtained regardless of
+how it is handled. A great deal of the success of any dry kiln--or any
+other apparatus, for that matter--depends upon intelligent operation.
+
+
+                  Operation of the "Blower" Dry Kiln
+
+It is essential that the operator be supplied with proper facilities
+to keep a record of the material as it is placed into the drying room,
+and when it is taken out. An accurate record should be kept of the
+temperature every two or three hours, for the different thicknesses
+and species of lumber, that he may have some reliable data to guide
+him in future cases.
+
+Any man possessing ordinary intelligence can operate dry kilns and
+secure satisfactory results, providing he will use good judgment and
+follow the basic instructions as outlined below:
+
+     1. When cold and before putting into operation, heat the
+     apparatus slowly until all pipes are hot, then start the fan
+     or blower, gradually bringing it up to its required speed.
+
+     2. See that _all_ steam supply valves are kept wide open,
+     unless you desire to lengthen the time required to dry the
+     material.
+
+     3. When using exhaust steam, the valve from the header
+     (which is a separate drip, independent of the trap
+     connection) must be kept wide open, but must be closed when
+     live steam is used on that part of the heater.
+
+     4. The engines as supplied by the manufacturers are
+     constructed to operate the fan or blower at a proper speed
+     with its throttle valve wide open, and with not less than 80
+     pounds pressure of steam.
+
+     5. If the return steam trap does not discharge regularly, it
+     is important that it be opened and thoroughly cleaned and
+     the valve seat re-ground.
+
+     6. As good air circulation is as essential as the proper
+     degree of heat, and as the volume of air and its contact
+     with the material to be dried depends upon the volume
+     delivered by the fan or blower, it is necessary to maintain
+     a regular and uniform speed of the engine.
+
+     7. Atmospheric openings must always be maintained in the fan
+     or heater room for fresh air supply.
+
+     8. Successful drying cannot be accomplished without ample
+     and free circulation of air at all times.
+
+If the above instructions are fully carried out, and good judgment
+used in the handling and operation of the blower kiln, no difficulties
+should be encountered in successfully drying the materials at hand.
+
+
+                  The "Pipe" or "Moist-air" Dry Kiln
+
+While in the blower class of dry kiln, the circulation is obtained by
+forced draft with the aid of fans or blowers, in the Moist-air kilns
+(see Fig. 31); the circulation is obtained by natural draft only,
+aided by the manipulation of dampers installed at the receiving end of
+the drying room, which lead to vertical flues through a stack to the
+outside atmosphere.
+
+The heat in these kilns is obtained by condensing steam in coils of
+pipe, which are placed underneath the material to be dried. As the
+degree of heat required, and steam pressure govern the amount of
+radiation, there are several types of radiating coils. In Fig. 32 will
+be seen the Single Row Heating Coils for live or high pressure steam,
+which are used when the low temperature is required. Figure 33 shows
+the Double (or 2) Row Heating Coils for live or high pressure steam.
+This apparatus is used when a medium temperature is required. In Fig.
+34 will be seen the Vertical Type Heating Coils which is recommended
+where exhaust or low-pressure steam is to be used, or may be used with
+live or high-pressure steam when high temperatures are desired.
+
+    [Illustration: Fig. 31. Section through a typical Moist-air
+    Dry Kiln.]
+
+These heating coils are usually installed in sections, which permit
+any degree of heat from the minimum to the maximum to be maintained by
+the elimination of, or the addition of, any number of heating
+sections. This gives a dry kiln for the drying of green softwoods, or
+by shutting off a portion of the radiating coils--thus reducing the
+temperature--a dry kiln for drying hardwoods, that will not stand the
+maximum degree of heat.
+
+    [Illustration: Fig. 32. Single Pipe Heating Apparatus for Dry
+    Kilns, arranged for the Use of Live Steam. For Low
+    Temperatures.]
+
+    [Illustration: Fig. 33. Double Pipe Heating Apparatus for Dry
+    Kilns, arranged for the Use of Live Steam. For Medium
+    Temperatures.]
+
+In the Moist-air or Natural Draft type of dry kiln, any degree of
+humidity, from clear and dry to a dense fog may be obtained; this is
+in fact, the main and most important feature of this type of dry kiln,
+and the most essential one in the drying of hardwoods.
+
+It is not generally understood that the length of a kiln has any
+effect upon the quantity of material that may be put through it, but
+it is a fact nevertheless that long kilns are much more effective, and
+produce a better quality of stock in less time than kilns of shorter
+length.
+
+Experience has proven that a kiln from 80 to 125 feet in length will
+produce the best results, and it should be the practice, where
+possible, to keep them within these figures. The reason for this is
+that in a long kiln there is a greater drop in temperature between the
+discharge end and the green or receiving end of the kiln.
+
+It is very essential that the conditions in the receiving end of the
+kiln, as far as the temperature and humidity are concerned, must go
+hand in hand.
+
+It has also been found that in a long kiln the desired conditions may
+be obtained with higher temperatures than with a shorter kiln;
+consequently higher temperatures may be carried in the discharge end
+of the kiln, thereby securing greater rapidity in drying. It is not
+unusual to find that a temperature of 200 degrees Fahrenheit is
+carried in the discharge end of a long dry kiln with safety, without
+in any way injuring the quality of the material, although, it would be
+better not to exceed 180 degrees in the discharge end, and about 120
+degrees in the receiving or green end in order to be on the safe side.
+
+
+                 Operation of the "Moist-air" Dry Kiln
+
+To obtain the best results these kilns should be kept in continuous
+operation when once started, that is, they should be operated
+continuously day and night. When not in operation at night or on
+Sundays, and the kiln is used to season green stock direct from the
+saw, the large doors at both ends of the kiln should be opened wide,
+or the material to be dried will "sap stain."
+
+    [Illustration: Fig. 34. Vertical Pipe Heating Apparatus for
+    Dry Kilns; may be used in Connection with either Live or
+    Exhaust Steam for High or Low Temperatures.]
+
+It is highly important that the operator attending any drying
+apparatus keep a minute and accurate record of the condition of the
+material as it is placed into the drying room, and its final condition
+when taken out.
+
+Records of the temperature and humidity should be taken frequently and
+at stated periods for the different thicknesses and species of
+material, in order that he may have reliable data to guide him in
+future operations.
+
+The following facts should be taken into consideration when operating
+the Moist-air dry kiln:
+
+     1. Before any material has been placed in the drying room,
+     the steam should be turned into the heating or radiating
+     coils, gradually warming them, and bringing the temperature
+     in the kiln up to the desired degree.
+
+     2. Care should be exercised that there is sufficient
+     humidity in the receiving or loading end of the kiln, in
+     order to guard against checking, case-hardening, etc.
+     Therefore it is essential that the steam spray at the
+     receiving or loading end of the kiln be properly
+     manipulated.
+
+     3. As the temperature depends principally upon the pressure
+     of steam carried in the boilers, maintain a steam pressure
+     of not less than 80 pounds at all times; it may range as
+     high as 100 pounds. The higher the temperature with its
+     relatively high humidity the more rapidly the drying will be
+     accomplished.
+
+     4. Since air circulation is as essential as the proper
+     degree of heat, and as its contact with the material to be
+     dried depends upon its free circulation, it is necessary
+     that the dampers for its admittance into, and its exit from,
+     the drying room be efficiently and properly operated.
+     Successful drying cannot be accomplished without ample and
+     free circulation of air at all times during the drying
+     process.
+
+If the above basic principles are carefully noted and followed out,
+and good common sense used in the handling and operation of the kiln
+apparatus, no serious difficulties should arise against the successful
+drying of the materials at hand.
+
+
+                        Choice of Drying Method
+
+At this point naturally arises the question: Which of the two classes
+of dry kilns, the "Moist-air" or "Blower" kiln is the better adapted
+for my particular needs?
+
+This must be determined entirely by the species of wood to be dried,
+its condition when it goes into the kiln, and what kind of finished
+product is to be manufactured from it.
+
+Almost any species of hardwood which has been subjected to
+air-seasoning for three months or more may be dried rapidly and in the
+best possible condition for glue-jointing and fine finishing with a
+"Blower" kiln, but green hardwood, direct from the saw, can only be
+successfully dried (if at all) in a "Moist-air" kiln.
+
+Most furniture factories have considerable bent stock which must of
+necessity be thoroughly steamed before bending. By steaming, the
+initial process of the Moist-air kiln has been consummated. Hence, the
+Blower kiln is better adapted to the drying of such stock than the
+Moist-air kiln would be, as the stock has been thoroughly soaked by
+the preliminary steaming, and all that is required is sufficient heat
+to volatilize the moisture, and a strong circulation of air to remove
+it as it comes to the surface.
+
+The Moist-air kiln is better adapted to the drying of tight cooperage
+stock, while the Blower kiln is almost universally used throughout the
+slack cooperage industry for the drying of its products.
+
+For the drying of heavy timbers, planks, blocks, carriage stock, etc.,
+and for all species of hardwood thicker than one inch, the Moist-air
+kiln is undoubtedly the best.
+
+Both types of kilns are equally well adapted to the drying of 1-inch
+green Norway and white pine, elm, hemlock, and such woods as are used
+in the manufacture of flooring, ceiling, siding, shingles, hoops, tub
+and pail stock, etc.
+
+The selection of one or the other for such work is largely matter of
+personal opinion.
+
+
+                       Kilns of Different Types
+
+All dry kilns as in use to-day are divided as to method of drying into
+two classes:
+
+    The "Pipe" or "Moist-air" kiln;
+    The "Blower" or "Hot Blast" kiln;
+
+both of which have been fully explained in a previous article.
+
+The above two classes are again subdivided into five different types
+of dry kilns as follows:
+
+    The "Progressive" kiln;
+    The "Apartment" kiln;
+    The "Pocket" kiln;
+    The "Tower" kiln;
+    The "Box" kiln.
+
+
+                      The "Progressive" Dry Kiln
+
+Dry kilns constructed so that the material goes in at one end and is
+taken out at the opposite end are called Progressive dry kilns, from
+the fact that the material gradually progresses through the kiln from
+one stage to another while drying (see Fig. 31).
+
+In the operation of the Progressive kiln, the material is first
+subjected to a sweating or steaming process at the receiving or
+loading end of the kiln with a low temperature and a relative high
+humidity. It then gradually progresses through the kiln into higher
+temperatures and lower humidities, as well as changes of air
+circulation, until it reaches the final stage at the discharge end of
+the kiln.
+
+Progressive kilns, in order to produce the most satisfactory results,
+especially in the drying of hardwoods or heavy softwood timbers,
+should be not less than 100 feet in length (see Fig. 35).
+
+In placing this type of kiln in operation, the following instructions
+should be carefully followed:
+
+When steam has been turned into the heating coils, and the kiln is
+fairly warm, place the first car of material to be dried in the drying
+room--preferably in the morning--about 25 feet from the kiln door on
+the receiving or loading end of the kiln, blocking the wheels so that
+it will remain stationary.
+
+    [Illustration: Fig. 35. Exterior View of Four Progressive Dry
+    Kilns, each 140 Feet long by 18 Feet wide. Cross-wise piling,
+    fire-proof construction.]
+
+Five hours later, or about noon, run in the second car and stop it
+about five feet from the first one placed in the drying room. Five
+hours later, or in the evening push car number two up against the
+first car; then run in car number three, stopping it about five feet
+from car number two.
+
+On the morning of the second day, push car number three against the
+others, and then move them all forward about 25 feet, and then run in
+car number four, stopping it about five feet from the car in advance
+of it. Five hours later, or about noon, run in car number five and
+stop it about five feet from car number four. In the evening or about
+five hours later, push these cars against the ones ahead, and run in
+loaded car number six, stopping it about five feet from the preceding
+car.
+
+On the morning of the third day, move all the cars forward about six
+feet; then run in loaded car number seven stop it about four feet from
+the car preceding it. Five hours later or about noon push this car
+against those in advance of it, and run in loaded car number eight
+moving all cars forward about six feet, and continue in this manner
+until the full complement of cars have been placed in the kiln. When
+the kiln has been filled, remove car number one and push all the
+remaining cars forward and run in the next loaded car, and continue in
+this manner as long as the kiln is in operation.
+
+As the temperature depends principally upon the pressure of steam,
+maintain a steam pressure of not less than 80 pounds at all times; it
+may range up to as high as 100 pounds. The higher the temperature with
+a relatively higher humidity the more rapidly the drying will be
+accomplished.
+
+If the above instructions are carried out, the temperatures,
+humidities, and air circulation properly manipulated, there should be
+complete success in the handling of this type of dry kiln.
+
+The Progressive type of dry kiln is adapted to such lines of
+manufacture that have large quantities of material to kiln-dry where
+the species to be dried is of a similiar nature or texture, and does
+not vary to any great extent in its thickness, such, for instance, as:
+
+    Oak flooring plants;
+    Maple flooring plants;
+    Cooperage plants;
+    Large box plants;
+    Furniture factories; etc.
+
+In the selection of this kind of dry kiln, consideration should be
+given to the question of ground space of sufficient length or
+dimension to accommodate a kiln of proper length for successful
+drying.
+
+
+                       The "Apartment" Dry Kiln
+
+The Apartment system of dry kilns are primarily designed for the
+drying of different kinds or sizes of material at the same time, a
+separate room or apartment being devoted to each species or size when
+the quantity is sufficient (see Fig. 36).
+
+These kilns are sometimes built single or in batteries of two or more,
+generally not exceeding 40 or 50 feet in length with doors and
+platforms at both ends the same as the Progressive kilns; but in
+operation each kiln is entirely filled at one loading and then closed,
+and the entire contents dried at one time, then emptied and again
+recharged.
+
+Any number of apartments may be built, and each apartment may be
+arranged to handle any number of cars, generally about three or four,
+or they may be so constructed that the material is piled directly upon
+the floor of the drying room.
+
+    [Illustration: Fig. 36. Exterior View of Six Apartment Dry
+    Kilns, each 10 Feet wide by 52 Feet long, End-wise Piling.
+    They are entirely of fire-proof construction and equipped
+    with double doors (Hussey asbestos outside and canvas
+    inside), and are also equipped with humidity and air control
+    dampers, which may be operated from the outside without
+    opening the kiln doors, which is a very good feature.]
+
+When cars are used, it is well to have a transfer car at each end of
+the kilns, and stub tracks for holding cars of dry material, and for
+the loading of the unseasoned stock, as in this manner the kilns may
+be kept in full operation at all times.
+
+In this type of dry kiln the material receives the same treatment and
+process that it would in a Progressive kiln. The advantages of
+Apartment kilns is manifest where certain conditions require the
+drying of numerous kinds as well as thicknesses of material at one and
+the same time. This method permits of several short drying rooms or
+apartments so that it is not necessary to mix hardwoods and softwoods,
+or thick and thin material in the same kiln room.
+
+In these small kilns the circulation is under perfect control, so that
+the efficiency is equal to that of the more extensive plants, and will
+readily appeal to manufacturers whose output calls for the prompt and
+constant seasoning of a large variety of small stock, rather than a
+large volume of material of uniform size and grade.
+
+Apartment kilns are recommended for industries where conditions
+require numerous kinds and thicknesses of material to be dried, such
+as:
+
+    Furniture factories;
+    Piano factories;
+    Interior woodwork mills;
+    Planing mills; etc.
+
+
+                         The "Pocket" Dry Kiln
+
+"Pocket" dry kilns (see Fig. 37) are generally built in batteries of
+several pockets. They have the tracks level and the lumber goes in and
+out at the same end. Each drying room is entirely filled at one time,
+the material is dried and then removed and the kiln again recharged.
+
+The length of "Pocket" kilns ranges generally from 14 feet to about 32
+feet.
+
+The interior equipment for this type of dry kiln is arranged very
+similiar to that used in the Apartment kiln. The heating or radiating
+coils and steam spray jets extend the whole length of the drying room,
+and are arranged for the use of either live or exhaust steam, as
+desired.
+
+Inasmuch as Pocket kilns have doors at one end only, this feature
+eliminates a certain amount of door exposure, which conduces towards
+economy in operation.
+
+In operating Pocket kilns, woods of different texture and thickness
+should be separated and placed in different drying rooms, and each
+kiln adjusted and operated to accommodate the peculiarities of the
+species and thickness of the material to be dried.
+
+    [Illustration: Fig. 37. Exterior View of Five Pocket Dry
+    Kilns, built in Two Batteries with the Front of each Set
+    facing the other, and a Transfer System between. They are
+    also equipped with the asbestos doors.]
+
+Naturally, the more complex the conditions of manufacturing wood
+products in any industry, the more difficult will be the proper
+drying of same. Pocket kilns, are, therefore, recommended for
+factories having several different kinds and thicknesses of material
+to dry in small quantities of each, such as:
+
+    Planing mills;
+    Chair factories;
+    Furniture factories;
+    Sash and door factories; etc.
+
+
+                         The "Tower" Dry Kiln
+
+The so-called "Tower" dry kiln (see Fig. 38) is designed for the rapid
+drying of small stuff in quantities. Although the general form of
+construction and the capacity of the individual bins or drying rooms
+may vary, the same essential method of operation is common to all.
+That is, the material itself, such as wooden novelties, loose staves,
+and heading for tubs, kits, and pails, for box stuff, kindling wood,
+etc., is dumped directly into the drying rooms from above, or through
+the roof, in such quantities as effectually to fill the bin, from
+which it is finally removed when dry, through the doors at the bottom.
+
+These dry kilns are usually operated as "Blower" kilns, the heating
+apparatus is generally located in a separate room or building adjacent
+to the main structure or drying rooms, and arranged so that the hot
+air discharged through the inlet duct (see illustration) is thoroughly
+distributed beneath a lattice floor upon which rests the material to
+be dried. Through this floor the air passes directly upward, between
+and around the stock, and finally returns to the fan or heating room.
+
+This return air duct is so arranged that by means of dampers, leading
+from each drying room, the air may be returned in any quantity to the
+fan room where it is mixed with fresh air and again used. This is one
+of the main features of economy of the blower system of drying, as by
+the employment of this return air system, considerable saving may be
+made in the amount of steam required for drying.
+
+    [Illustration: Fig. 38. Exterior and Sectional View of a
+    Battery of Tower Dry Kilns. This is a "Blower" or "Hot Blast"
+    type, and shows the arrangement of the fan blower, engine,
+    etc. This type of dry kin is used principally for the
+    seasoning of small, loose material.]
+
+The lattice floors in this type of dry kiln are built on an incline,
+which arrangement materially lessens the cost, and increases the
+convenience with which the dried stock may be removed from the bins or
+drying rooms.
+
+In operation, the material is conveyed in cars or trucks on an
+overhead trestle--which is inclosed--from which the material to be
+dried is dumped directly into the drying rooms or bins, through
+hoppers arranged for that purpose thereby creating considerable saving
+in the handling of the material to be dried into the kiln. The entire
+arrangement thus secures the maximum capacity, with a minimum amount
+of floor space, with the least expense. Of course, the higher these
+kilns are built, the less relative cost for a given result in the
+amount of material dried.
+
+In some instances, these kilns are built less in height and up against
+an embankment so that teamloads of material may be run directly onto
+the roof of the kilns, and dumped through the hoppers into the drying
+rooms or bins, thus again reducing to a minimum the cost of this
+handling.
+
+The return air duct plays an important part in both of these methods
+of filling, permitting the air to become saturated to the maximum
+desired, and utilizing much of the heat contained therein, which would
+otherwise escape to the atmosphere.
+
+The "Tower" kiln is especially adapted to factories of the following
+class:
+
+    Sawmills;
+    Novelty factories;
+    Woodenware factories;
+    Tub and pail factories; etc.
+
+
+                          The "Box" Dry Kiln
+
+The "Box" kiln shown in Figure 39 is an exterior view of a kiln of
+this type which is 20 feet wide, 19 feet deep, and 14 feet high, which
+is the size generally used when the space will permit.
+
+Box kilns are used mostly where only a small quantity of material is
+to be dried. They are not equipped with trucks or cars, the material
+to be dried being piled upon a raised platform inside the drying
+room. This arrangement, therefore, makes them of less cost than the
+other types of dry kilns.
+
+They are particularly adapted to any and all species and size of
+lumber to be dried in very small quantities.
+
+    [Illustration: Fig. 39. Exterior view of the Box Dry Kiln.
+    This particular kiln is 20 feet wide, 19 feet deep and 14
+    feet high. Box kilns are used mostly where only a small
+    amount of kiln-dried lumber of various sizes is required.
+    They are not equipped with trucks or cars, and therefore cost
+    less to construct than any other type of dry kiln.]
+
+In these small kilns the circulation is under perfect control, so that
+the efficiency is equal to that of the more extensive plants.
+
+These special kilns will readily appeal to manufacturers, whose output
+calls for the prompt and constant seasoning of a large variety of
+small stock, rather than a large volume material of uniform size and
+grade.
+
+
+
+
+                             SECTION XIII
+
+                         DRY KILN SPECIALTIES
+
+                    KILN CARS AND METHOD OF LOADING
+
+
+Within recent years, the edge-wise piling of lumber (see Figs. 40 and
+41), upon kiln cars has met with considerable favor on account of its
+many advantages over the older method of flat piling. It has been
+proven that lumber stacked edge-wise dries more uniformly and rapidly,
+and with practically no warping or twisting of the material, and that
+it is finally discharged from the dry kiln in a much better and
+brighter condition. This method of piling also considerably increases
+the holding and consequent drying capacities of the dry kiln by reason
+of the increased carrying capacities of the kiln cars, and the shorter
+period of time required for drying the material.
+
+    [Illustration: Fig. 40. Car Loaded with Lumber on its Edges
+    by the Automatic Stacker, to go into the Dry Kiln cross-wise.
+    Equipped with two edge piling kiln trucks.]
+
+In Figures 42 and 43 are shown different views of the automatic lumber
+stacker for edge-wise piling of lumber on kiln cars. Many users of
+automatic stackers report that the grade of their lumber is raised to
+such an extent that the system would be profitable for this reason
+alone, not taking into consideration the added saving in time and
+labor, which to anyone's mind should be the most important item.
+
+    [Illustration: Fig. 41. Car Loaded with Lumber on its Edges
+    by the Automatic Stacker, to go into the Dry Kiln end-wise.
+    The bunks on which the lumber rests are channel steel. The
+    end sockets are malleable iron and made for I-beam stakes.]
+
+In operation, the lumber is carried to these automatic stackers on
+transfer chains or chain conveyors, and passes on to the stacker
+table. When the table is covered with boards, the "lumber" lever is
+pulled by the operator, which raises a stop, preventing any more
+lumber leaving the chain conveyor. The "table" lever then operates the
+friction drive and raises the table filled with the boards to a
+vertical position. As the table goes up, it raises the latches, which
+fall into place behind the piling strips that had been previously laid
+on the table. When the table returns to the lower position, a new set
+of piling strips are put in place on the table, and the stream of
+boards which has been accumulating on the conveyor chain are again
+permitted to flow onto the table. As each layer of lumber is added,
+the kiln car is forced out against a strong tension. When the car is
+loaded, binders are put on over the stakes by means of a powerful
+lever arrangement.
+
+    [Illustration: Fig. 42. The above illustration shows the
+    construction of the Automatic Lumber Stacker for edge piling
+    of lumber to go into the dry kiln end-wise.]
+
+    [Illustration: Fig. 43. The above illustration shows the
+    construction of the Automatic Lumber Stacker for edge piling
+    of lumber to go into the dry kiln cross-wise.]
+
+    [Illustration: Fig. 44. The above illustration shows a
+    battery of Three Automatic Lumber Stackers.]
+
+    [Illustration: Fig. 45. The above illustration shows another
+    battery of Three Automatic Lumber Stackers.]
+
+    [Illustration: Fig. 46. Cars Loaded with Lumber on its Edges
+    by the Automatic Lumber Stackers.]
+
+After leaving the dry kilns, the loaded car is transferred to the
+unstacker (see Fig. 47). Here it is placed on the unstacker car which,
+by means of a tension device, holds the load of lumber tight against
+the vertical frame of the unstacker. The frame of the unstacker is
+triangular and has a series of chains. Each chain has two special
+links with projecting lugs. The chains all travel in unison. The lug
+links engage a layer of boards, sliding the entire layer vertically,
+and the boards, one at a time, fall over the top of the unstacker
+frame onto the inclined table, and from there onto conveyor chains
+from which they may be delivered to any point desired, depending upon
+the length and direction of the chain conveyor.
+
+With these unstackers one man can easily unload a kiln car in twenty
+minutes or less.
+
+    [Illustration: Fig. 47. The Lumber Unstacker Car, used for
+    unloading cars of Lumber loaded by the Automatic Stacker.]
+
+    [Illustration: Fig. 48. The Lumber Unstacker Car and
+    Unstacker, used for unloading Lumber loaded by the Automatic
+    Stacker.]
+
+The experience of many users prove that these edge stacking machines
+are not alike. This is important, because there is one feature of edge
+stacking that must not be overlooked. Unless each layer of boards is
+forced into place by power and held under a strong pressure, much
+slack will accumulate in an entire load, and the subsequent handling
+of the kiln cars, and the effect of the kiln-drying will loosen up the
+load until there is a tendency for the layers to telescope. And unless
+the boards are held in place rigidly and with strong pressure they
+will have a tendency to warp.
+
+    [Illustration: Fig. 49. The above illustration shows method
+    of loading kiln cars with veneer on its edges by the use of
+    the Tilting Platform.]
+
+A kiln car of edge-stacked lumber, properly piled, is made up of
+alternate solid sheets of lumber and vertical open-air spaces, so that
+the hot air and vapors rise naturally and freely through the lumber,
+drying both sides of the board evenly. The distribution of the heat
+and moisture being even and uniform, the drying process is naturally
+quickened, and there is no opportunity or tendency for the lumber to
+warp.
+
+In Figure 49 will be seen a method of loading kiln cars with veneer on
+edge by the use of a tilting platform. On the right of the
+illustration is seen a partially loaded kiln car tilted to an angle of
+45 degrees, to facilitate the placing of the veneer on the car. At
+the left is a completely loaded car ready to enter the dry kiln.
+
+Gum, poplar, and pine veneers are satisfactorily dried in this manner
+in from 8 to 24 hours.
+
+In Figure 50 will be seen method of piling lumber on the flat,
+"cross-wise" of the dry kiln when same has three tracks.
+
+    [Illustration: Fig. 50. Method of Loading lumber on its Flat,
+    cross-wise of the Dry Kiln when same has Three Tracks.]
+
+In Figure 51 will be seen another method of piling lumber on the flat,
+"cross-wise" of the dry kiln when same has three tracks.
+
+In Figure 52 will be seen method of piling lumber on the flat,
+"end-wise" of the dry kiln when same has two tracks.
+
+In Figure 53 will be seen another method of piling lumber on the flat,
+"end-wise" of the dry kiln when same has two tracks.
+
+In Figure 54 will be seen method of piling slack or tight barrel
+staves "cross-wise" of the kiln when same has three tracks.
+
+In Figure 55 will be seen another method of piling slack or tight
+barrel staves "cross-wise" of the dry kiln when same has three tracks.
+
+In Figure 56 will be seen method of piling small tub or pail staves
+"cross-wise" of the dry kiln when same has two tracks.
+
+In Figure 57 will be seen method of piling bundled staves "cross-wise"
+of the dry kiln when same has two tracks.
+
+    [Illustration: Fig. 51. Method of loading Lumber on its Flat,
+    cross-wise of the Dry Kiln when same has Three Tracks.]
+
+    [Illustration: Fig. 52. Method of loading Lumber on its Flat,
+    end-wise of the Dry Kiln by the Use of the Single-sill or
+    Dolly Truck.]
+
+    [Illustration: Fig. 53. Method of loading Lumber on its Flat,
+    end-wise of the Dry Kiln by the Use of the Double-sill
+    Truck.]
+
+    [Illustration: Fig. 54. Method of loading Kiln Car with Tight
+    or Slack Barrel Staves cross-wise of Dry Kiln.]
+
+    [Illustration: Fig. 55. Method of loading Kiln Car with Tight
+    or Slack Barrel Staves cross-wise of Dry Kiln.]
+
+    [Illustration: Fig. 56. Method of loading Kiln Car with Tub
+    or Pail Staves cross-wise of Dry Kiln.]
+
+    [Illustration: Fig. 57. Method of loading Kiln Car with
+    Bundled Staves cross-wise of Dry Kiln.]
+
+In Figure 58 will be seen method of piling shingles "cross-wise" of
+dry kiln when same has three tracks.
+
+In Figure 59 will be seen another method of piling shingles
+"cross-wise" of the dry kiln when same has three tracks.
+
+    [Illustration: Fig. 58. Method of loading Kiln Car with
+    Shingles cross-wise of Dry Kiln.]
+
+    [Illustration: Fig. 59. Method of loading Kiln Car with
+    Shingles cross-wise of Dry Kiln.]
+
+In Figure 60 will be seen method of piling shingles "end-wise" of the
+dry kiln when same has two tracks.
+
+In Figure 61 will be seen a kiln car designed for handling short tub
+or pail staves through a dry kiln.
+
+    [Illustration: Fig. 60. Car loaded with 100,000 Shingles.
+    Equipped with four long end-wise piling trucks and to go into
+    dry kiln end-wise.]
+
+    [Illustration: Fig. 61. Kiln Car designed for handling Short
+    Tub or Pail Staves through a Dry Kiln.]
+
+In Figure 62 will be seen a kiln car designed for short piece stock
+through a dry kiln.
+
+In Figure 63 will be seen a type of truck designed for the handling of
+stave bolts about a stave mill or through a steam box.
+
+In Figure 64 will be seen another type of truck designed for the
+handling of stave bolts about a stave mill or through a steam box.
+
+In Figure 65 will be seen another type of truck designed for the
+handling of stave bolts about a stave mill or through a steam box.
+
+In Figure 66 will be seen another type of truck designed for the
+handling of stave bolts about a stave mill or through a steam box.
+
+In Figure 67 will be seen another type of truck designed for the
+handling of stave bolts about a stave mill or through a steam box.
+
+In Figure 68 will be seen another type of truck designed for the
+handling of stave bolts about a stave mill or through a steam box.
+
+In Figure 69 will be seen the Regular 3-rail Transfer Car designed for
+the handling of 2-rail kiln cars which have been loaded "end-wise."
+
+In Figure 70 will be seen another type of Regular 3-rail Transfer Car
+designed for the handling of 2-rail kiln cars which have been loaded
+"end-wise."
+
+In Figure 71 will be seen a Specially-designed 4-rail Transfer Car for
+2-rail kiln cars which have been built to accommodate extra long
+material to be dried.
+
+In Figure 72 will be seen the Regular 2-rail Transfer Car designed for
+the handling of 3-rail kiln cars which have been loaded "cross-wise."
+
+In Figure 73 will be seen another type of Regular 2-rail Transfer Car
+designed for the handling of 3-rail kiln cars which have been loaded
+"cross-wise."
+
+In Figure 74 will be seen the Regular 2-rail Underslung type of
+Transfer Car designed for the handling of 3-rail kiln cars which have
+been loaded "cross-wise." Two important features in the construction
+of this transfer car make it extremely easy in its operation. It has
+extra large wheels, diameter 13-1/2 inches, and being underslung, the
+top of its rails are no higher than the other types of transfer cars.
+Note the relative size of the wheels in the illustration, yet the car
+is only about 10 inches in height.
+
+    [Illustration: Fig. 62. Kiln Car Designed for handling Short
+    Piece Stock through a Dry Kiln.]
+
+    [Illustration: Fig. 63. A Stave Bolt Truck.]
+
+    [Illustration: Fig. 64. A Stave Bolt Truck.]
+
+    [Illustration: Fig. 65. A Stave Bolt Truck.]
+
+    [Illustration: Fig. 66. A Stave Bolt Truck.]
+
+    [Illustration: Fig. 67. A Stave Bolt Truck.]
+
+    [Illustration: Fig. 68. A Stave Bolt Truck.]
+
+    [Illustration: Fig. 69. A Regular 3-Rail Transfer Truck.]
+
+    [Illustration: Fig. 70. A Regular 3-Rail Transfer Truck.]
+
+    [Illustration: Fig. 71. A Special 4-Rail Transfer Truck.]
+
+    [Illustration: Fig. 72. A Regular 2-Rail Transfer Truck.]
+
+    [Illustration: Fig. 73. A Regular 2-Rail Transfer Truck.]
+
+    [Illustration: Fig. 74. A Regular 2-Rail Underslung Transfer
+    Truck.]
+
+    [Illustration: Fig. 75. A Regular 3-Rail Underslung Transfer
+    Truck.]
+
+In Figure 75 will be seen the Regular 3-rail Underslung type of
+Transfer Car designed for the handling of 2-rail kiln cars which have
+been loaded "end-wise." This car also has the important features of
+large diameter wheels and low rail construction, which make it very
+easy in its operation.
+
+    [Illustration: Fig. 76. A Special 2-Rail Flexible Transfer
+    Truck.]
+
+In Figure 76 will be seen the Special 2-rail Flexible type of Transfer
+Car designed for the handling of 3-rail kiln cars which have been
+loaded "cross-wise." This car is equipped with double the usual number
+of wheels, and by making each set of trucks a separate unit (the front
+and rear trucks being bolted to a steel beam with malleable iron
+connection), a slight up-and-down movement is permitted, which enables
+this transfer car to adjust itself to any unevenness in the track,
+which is a very good feature.
+
+In Figure 77 will be seen the Regular Transfer Car designed for the
+handling of stave bolt trucks.
+
+In Figure 78 will be seen another type of Regular Transfer Car
+designed for the handling of stave bolt trucks.
+
+In Figure 79 will be seen a Special Transfer Car designed for the
+handling of stave bolt trucks.
+
+    [Illustration: Fig. 77. A Regular Transfer Car for handling
+    Stave Bolt Trucks.]
+
+    [Illustration: Fig. 78. A Regular Transfer Car for handling
+    Stave Bolt Trucks.]
+
+    [Illustration: Fig. 79. A Special Transfer Car for handling
+    Stave Bolt Trucks.]
+
+In Figure 80 will be seen the Regular Channel-iron Kiln Truck designed
+for edge piling "cross-wise" of the dry kiln.
+
+In Figure 81 will be seen another type of Regular Channel-iron Kiln
+Truck designed for edge piling "cross-wise" of the dry kiln.
+
+    [Illustration: Fig. 80. A Regular Channel-iron Kiln Truck.]
+
+    [Illustration: Fig. 81. A Regular Channel-iron Kiln Truck.]
+
+In Figure 82 will be seen the Regular Channel-iron Kiln Truck designed
+for flat piling "end-wise" of the dry kiln.
+
+    [Illustration: Fig. 82. A Regular Channel-iron Kiln Truck.]
+
+    [Illustration: Fig. 83. A Regular Channel-iron Kiln Truck.]
+
+    [Illustration: Fig. 84. A Regular Single-sill or Dolly Kiln
+    Truck.]
+
+In Figure 83 will be seen the Regular Channel-iron Kiln Truck with
+I-Beam cross-pieces designed for flat piling "end-wise" of the dry
+kiln.
+
+In Figure 84 will be seen the Regular Small Dolly Kiln Truck designed
+for flat piling "end-wise" of the dry kiln.
+
+
+                     Different Types of Kiln Doors
+
+In Figure 85 will be seen the Asbestos-lined Door. The construction of
+this kiln door is such that it has no tendency to warp or twist. The
+framework is solid and the body is made of thin slats placed so that
+the slat on either side covers the open space of the other with
+asbestos roofing fabric in between. This makes a comparatively light
+and inexpensive door, and one that absolutely holds the heat. These
+doors may be built either swinging, hoisting, or sliding.
+
+    [Illustration: Fig. 85. An Asbestos-lined Kiln Door of the
+    Hinge Type.]
+
+In Figure 86 will be seen the Twin Carrier type of door hangers with
+doors loaded and rolling clear of the opening.
+
+    [Illustration: Fig. 86. Twin Carrier with Kiln Door loaded
+    and rolling clear of Opening.]
+
+    [Illustration: Fig. 87. Twin Carriers for Kiln Doors 18 to 35
+    Feet wide.]
+
+In Figure 87 will be seen the Twin Carrier for doors 18 to 35 feet
+wide, idle on a section of the track.
+
+In Figure 88 will be seen another type of carrier for kiln doors.
+
+In Figure 89 will be seen the preceding type of kiln door carrier in
+operation.
+
+In Figure 90 will be seen another type of carrier for kiln doors.
+
+In Figure 91 will be seen kiln doors seated, wood construction,
+showing 3-1/2" × 5-3/4" inch-track timbers and trusses, supported on
+4-inch by 6-inch jamb posts. "T" rail track, top and side, inclined
+shelves on which the kiln door rests. Track timber not trussed on
+openings under 12 feet wide.
+
+    [Illustration: Fig. 88. Kiln Door Carrier engaged to Door
+    Ready for lifting.]
+
+In Figure 92 will be seen kiln doors seated, fire-proof construction,
+showing 12-inch, channel, steel lintels, 2" × 2" steel angle mullions,
+track brackets bolted to the steel lintels and "T" rail track. No
+track timbers or trusses used.
+
+    [Illustration: Fig. 89. Kiln Door Carrier shown on Doors of
+    Wood Construction.]
+
+    [Illustration: Fig. 90. Kiln Door Construction with Door
+    Carrier out of Sight.]
+
+    [Illustration: Fig. 91. Kiln Door Construction. Doors Seated.
+    Wood Construction.]
+
+    [Illustration: Fig. 92. Kiln Door Construction. Doors Seated.
+    Fire-proof Construction.]
+
+
+
+
+                              SECTION XIV
+
+                   HELPFUL APPLIANCES IN KILN-DRYING
+
+
+                         The Humidity Diagram
+
+    [Illustration: Fig. 93. The United States Forest Service
+    Humidity Diagram for determination of Absolute Humidities.
+    Dew Points and Vapor Pressures; also Relative Humidities by
+    means of Wet and Dry-Bulb Thermometer, for any temperatures
+    and change in temperature.]
+
+Some simple means of determining humidities and changes in humidity
+brought about by changes in temperature in the dry kiln without the
+use of tables is almost a necessity. To meet this requirement the
+United States Forestry Service has devised the Humidity Diagram shown
+in Figure 93. It differs in several respects from the hydrodeiks now
+in use.
+
+The purpose of the humidity diagram is to enable the dry-kiln operator
+to determine quickly the humidity conditions and vapor pressure, as
+well as the changes which take place with changes of temperature. The
+diagram above is adapted to the direct solution of problems of this
+character without recourse to tables or mathematical calculations.
+
+The humidity diagram consists of two distinct sets of curves on the
+same sheet. One set, the convex curves, is for the determination of
+relative humidity of wet-and-dry-bulb hygrometer or psychrometer; the
+other, the concave curves, is derived from the vapor pressures and
+shows the amount of moisture per cubic foot at relative humidities and
+temperatures when read at the dew-point. The latter curves, therefore,
+are independent of all variables affecting the wet-bulb readings. They
+are proportional to vapor pressures, not to density, and, therefore,
+may be followed from one temperature to another with correctness. The
+short dashes show the correction (increase or decrease) which is
+necessary in the relative humidity, read from the convex curves, with
+an increase or decrease from the normal barometric pressure of 30
+inches, for which the curves have been plotted. This correction,
+except for very low temperatures, is so small that it may usually be
+disregarded.
+
+The ordinates, or vertical distances, are relative humidity expressed
+in per cent of saturation, from 0 per cent at the bottom to 100 per
+cent at the top. The abscissae, or horizontal distances, are
+temperatures in degrees Fahrenheit from 30 degrees below zero, at the
+left, to 220 degrees above, at the right.
+
+
+                            Examples of Use
+
+The application of the humidity diagram can best be understood by
+sample problems. These problems also show the wide range of conditions
+to which the diagram will apply.
+
+     EXAMPLE 1. To find the relative humidity by use of
+     wet-and-dry-bulb hygrometer or psychrometer:
+
+     Place the instrument in a strong circulation of air, or wave
+     it to and fro. Read the temperature of the dry bulb and the
+     wet, and subtract. Find on the horizontal line the
+     temperature shown by the dry-bulb thermometer. Follow the
+     vertical line from this point till it intersects with the
+     convex curve marked with the difference between the wet and
+     dry readings. The horizontal line passing through this
+     intersection will give the relative humidity.
+
+     Example: Dry bulb 70°, wet bulb 62°, difference 8°. Find 70°
+     on the horizontal line of temperature. Follow up the
+     vertical line from 70° until it intersects with the convex
+     curve marked 8°. The horizontal line passing through this
+     intersection shows the relative humidity to be 64 per cent.
+
+     EXAMPLE 2. To find how much water per cubic foot is
+     contained in the air:
+
+     Find the relative humidity as in example 1. Then the nearest
+     concave curve gives the weight of water in grains per cubic
+     foot when the air is cooled to the dew-point. Using the same
+     quantities as in example 1, this will be slightly more than
+     5 grains.
+
+     EXAMPLE 3. To find the amount of water required to saturate
+     air at a given temperature:
+
+     Find on the top line (100 per cent humidity) the given
+     temperature; the concave curve intersecting at or near this
+     point gives the number of grains per cubic foot.
+     (Interpolate, if great accuracy is desired.)
+
+     EXAMPLE 4. To find the dew-point:
+
+     Obtain the relative humidity as in example 1. Then follow up
+     parallel to the nearest concave curve until the top
+     horizontal (indicating 100 per cent relative humidity) is
+     reached. The temperature on this horizontal line at the
+     point reached will be the dew-point.
+
+     Example: Dry bulb 70°, wet bulb 62°. On the vertical line
+     for 70° find the intersection with the hygrometer (convex)
+     curve for 8°. This will be found at nearly 64 per cent
+     relative humidity. Then follow up parallel with the vapor
+     pressure (concave) curve marked 5 grains to its intersection
+     at the top of the chart with the 100 per cent humidity line.
+     This gives the dew-point as 57°.
+
+     EXAMPLE 5. To find the change in the relative humidity
+     produced by a change in temperature:
+
+     Example: The air at 70° Fahr. is found to contain 64 per
+     cent humidity; what will be its relative humidity if heated
+     to 150° Fahr.? Starting from the intersection of the
+     designated humidity and temperature coordinates, follow the
+     vapor-pressure curve (concave) until it intersects the 150°
+     temperature ordinate. The horizontal line then reads 6 per
+     cent relative humidity. The same operation applies to
+     reductions in temperature. In the above example what is the
+     humidity at 60°? Following parallel to the same curve in the
+     opposite direction until it intersects the 60° ordinate
+     gives 90 per cent; at 57° it becomes 100 per cent, reaching
+     the dew-point.
+
+     EXAMPLE 6. To find the amount of condensation produced by
+     lowering the temperature:
+
+     Example: At 150° the wet bulb reads 132°. How much water
+     would be condensed if the temperature were lowered to 70°?
+     The intersection of the hygrometer curve for 18° (150°-132°)
+     with temperature line for 150° shows a relative humidity of
+     60 per cent. The vapor-pressure curve (concave) followed up
+     to the 100 per cent relative humidity line shows 45 grains
+     per cubic foot at the dew-point, which corresponds to a
+     temperature of 130°. At 70° it is seen that the air can
+     contain but 8 grains per cubic foot (saturation).
+     Consequently, there will be condensed 45 minus 8, or 37
+     grains per cubic foot of space measured at the dew-point.
+
+     EXAMPLE 7. To find the amount of water required to produce
+     saturation by a given rise in temperature:
+
+     Example: Take the values given in example 5. The air at the
+     dew-point contains slightly over 5 grains per cubic foot. At
+     150° it is capable of containing 73 grains per cubic foot.
+     Consequently, 73-5=68 grains of water which can be
+     evaporated per cubic foot of space at the dew-point when the
+     temperature is raised to 150°. But the latent heat necessary
+     to produce evaporation must be supplied in addition to the
+     heat required to raise the air to 150°.
+
+     EXAMPLE 8. To find the amount of water evaporated during a
+     given change of temperature and humidity:
+
+     Example: At 70° suppose the humidity is found to be 64 per
+     cent and at 150° it is found to be 60 per cent. How much
+     water has been evaporated per cubic foot of space? At 70°
+     temperature and 64 per cent humidity there are 5 grains of
+     water present per cubic foot at the dew-point (example 2).
+     At 150° and 60 per cent humidity there are 45 grains
+     present. Therefore, 45-5=40 grains of water which have been
+     evaporated per cubic foot of space, figuring all volumes at
+     the dew-point.
+
+     EXAMPLE 9. To correct readings of the hygrometer for changes
+     in barometric pressure:
+
+     A change of pressure affects the reading of the wet bulb.
+     The chart applies at a barometric pressure of 30 inches,
+     and, except for great accuracy, no correction is generally
+     necessary.
+
+     Find the relative humidity as usual. Then look for the
+     nearest barometer line (indicated by dashes). At the end of
+     each barometer line will be found a fraction which
+     represents the proportion of the relative humidity already
+     found, which must be added or subtracted for a change in
+     barometric pressure. If the barometer reading is less than
+     30 inches, add; if greater than 30 inches, subtract. The
+     figures given are for a change of 1 inch; for other changes
+     use proportional amounts. Thus, for a change of 2 inches use
+     twice the indicated ratio; for half an inch use half, and so
+     on.
+
+     Example: Dry bulb 67°, wet bulb 51°, barometer 28 inches.
+     The relative humidity is found, by the method given in
+     example 1, to equal 30 per cent. The barometric line--gives
+     a value of 3/100H for each inch of change. Since the
+     barometer is 2 inches below 30, multiply 3/100H by 2, giving
+     6/100H. The correction will, therefore, be 6/100 of 30,
+     which equals 1.8. Since the barometer is below 30, this is
+     to be added, giving a corrected relative humidity of 31.8
+     per cent.
+
+     This has nothing to do with the vapor pressure (concave)
+     curves, which are independent of barometric pressure, and
+     consequently does not affect the solution of the previous
+     problems.
+
+     EXAMPLE 10. At what temperature must the condenser be
+     maintained to produce a given humidity?
+
+     Example: Suppose the temperature in the drying room is to be
+     kept at 150° Fahr., and a humidity of 80 per cent is
+     desired. If the humidity is in excess of 80 per cent the air
+     must be cooled to the dew-point corresponding to this
+     condition (see example 4), which in this case is 141.5°.
+
+     Hence, if the condenser cools the air to this dew point the
+     required condition is obtained when the air is again heated
+     to the initial temperature.
+
+     EXAMPLE 11. Determination of relative humidity by the
+     dew-point:
+
+     The quantity of moisture present and relative humidity for
+     any given temperature may be determined directly and
+     accurately by finding the dew-point and applying the concave
+     (vapor-pressure) curves. This does away with the necessity
+     for the empirical convex curves and wet-and-dry-bulb
+     readings. To find the dew-point some form of apparatus,
+     consisting essentially of a thin glass vessel containing a
+     thermometer and a volatile liquid, such as ether, may be
+     used. The vessel is gradually cooled through the evaporation
+     of the liquid, accelerated by forcing air through a tube
+     until a haze or dimness, due to condensation from the
+     surrounding air, first appears upon the brighter outer
+     surface of the glass. The temperature at which the haze
+     first appears is the dew-point. Several trials should be
+     made for this temperature determination, using the average
+     temperature at which the haze appears and disappears.
+
+     To determine the relative humidity of the surrounding air by
+     means of the dew-point thus determined, find the concave
+     curve intersecting the top horizontal (100 per cent
+     relative humidity) line nearest the dew-point temperature.
+     Follow parallel with this curve till it intersects the
+     vertical line representing the temperature of the
+     surrounding air. The horizontal line passing through this
+     intersection will give the relative humidity.
+
+     Example: Temperature of surrounding air is 80; dew-point is
+     61; relative humidity is 53 per cent.
+
+     The dew-point determination is, however, not as convenient
+     to make as the wet-and-dry-bulb hygrometer readings.
+     Therefore, the hygrometer (convex) curves are ordinarily
+     more useful in determining relative humidities.
+
+
+                             The Hygrodeik
+
+In Figure 94 will be seen the Hygrodeik. This instrument is used to
+determine the amount of moisture in the atmosphere. It is a very
+useful instrument, as the readings may be taken direct with accuracy.
+
+To find the relative humidity in the atmosphere, swing the index hand
+to the left of the chart, and adjust the sliding pointer to that
+degree of the wet-bulb thermometer scale at which the mercury stands.
+Then swing the index hand to the right until the sliding pointer
+intersects the curved line, which extends downwards to the left from
+the degree of the dry-bulb thermometer scale, indicated by the top of
+the mercury column in the dry-bulb tube.
+
+At that intersection, the index hand will point to the relative
+humidity on scale at bottom of chart (for example see Fig. 94). Should
+the temperature indicated by the wet-bulb thermometer be 60 degrees,
+and that of the dry-bulb 70 degrees, the index hand will indicate
+humidity 55 degrees, when the pointer rests on the intersecting line
+of 60 degrees and 80 degrees.
+
+
+                       The Recording Hygrometer
+
+In Figure 95 is shown the Recording Hygrometer complete with wet and
+dry bulbs, two connecting tubes and two recording pens and special
+moistening device for supplying water to the wet bulb.
+
+This equipment is designed particularly for use in connection with dry
+rooms and dry kilns and is arranged so that the recording instrument
+and the water supply bottle may be installed outside of the dry kiln
+or drying room, while the wet and dry bulbs are both installed inside
+the room or kiln at the point where it is desired to measure the
+humidity. This instrument records on a weekly chart the humidity for
+each hour of the day, during the entire week.
+
+    [Illustration: Fig. 94. The Hygrodeik.]
+
+
+                      The Registering Hygrometer
+
+In Figure 96 is shown the Registering Hygrometer, which consists of
+two especially constructed thermometers. The special feature of the
+thermometers permits placing the instrument in the dry kiln without
+entering the drying room, through a small opening, where it is left
+for about 20 minutes.
+
+    [Illustration: Fig. 95. The Recording Hygrometer, Complete
+    with Wet and Dry Bulbs. This instrument records on a weekly
+    chart the humidity for each hour of the day, during the
+    entire week.]
+
+The temperature of both the dry and wet bulbs are automatically
+recorded, and the outside temperature will not affect the thermometers
+when removed from the kiln. From these recorded temperatures, as shown
+when the instrument is removed from the kiln, the humidity can be
+easily determined from a simple form of chart which is furnished free
+by the makers with each instrument.
+
+
+                       The Recording Thermometer
+
+    [Illustration: Fig. 96. The Registering Hygrometer.]
+
+    [Illustration: Fig. 97. The Recording Thermometer.]
+
+In Figure 97 is shown the Recording Thermometer for observing and
+recording the temperatures within a dry kiln, and thus obtaining a
+check upon its operation. This instrument is constructed to record
+automatically, upon a circular chart, the temperatures prevailing
+within the drying room at all times of the day and night, and serves
+not only as a means of keeping an accurate record of the operation of
+the dry kiln, but as a valuable check upon the attendant in charge of
+the drying process.
+
+    [Illustration: Fig. 98. The Registering Thermometer.]
+
+    [Illustration: Fig. 99. The Recording Steam-Pressure Gauge.]
+
+
+                      The Registering Thermometer
+
+In Figure 98 is shown the Registering Thermometer, which is a less
+expensive instrument than that shown in Figure 97, but by its use the
+maximum and minimum temperatures in the drying room during a given
+period can be determined.
+
+
+                       The Recording Steam Gauge
+
+In Figure 99 is shown the Recording Steam Pressure Gauge, which is
+used for accurately recording the steam pressures kept in the boilers.
+This instrument may be mounted near the boilers, or may be located at
+any distance necessary, giving a true and accurate record of the
+fluctuations of the steam pressure that may take place within the
+boilers, and is a check upon both the day and night boiler firemen.
+
+
+                       The Troemroid Scalometer
+
+In Figure 100 is shown the Troemroid Scalometer. This instrument is a
+special scale of extreme accuracy, fitted with agate bearings with
+screw adjustment for balancing. The beam is graduated from 0 to 2
+ounces, divided into 100 parts, each division representing 1-50th of
+an ounce; and by using the pointer attached to the beam weight, the
+1-100th part of an ounce can be weighed.
+
+    [Illustration: Fig. 100. The Troemroid Scalometer.]
+
+The percentage table No. II has a range from one half of 1 per cent to
+30 per cent and is designed for use where extremely fine results are
+needed, or where a very small amount of moisture is present. Table
+No. III ranges from 30 per cent up to 90 per cent. These instruments
+are in three models as described below.
+
+     MODEL A. (One cylinder) ranges from 1/2 of 1 per cent to 30
+     per cent and is to be used for testing moisture contents in
+     kiln-dried and air-dried lumber.
+
+     MODEL B. (Two cylinders) ranges from 1/2 of 1 per cent up to
+     90 per cent and is to be used for testing the moisture
+     contents of kiln-dried, air-dried, and green lumber.
+
+     MODEL C. (One cylinder) ranges from 30 per cent to 90 per
+     cent and is applicable to green lumber only.
+
+=Test Samples.=--The green boards and all other boards intended for
+testing should be selected from boards of fair average quality. If
+air-dried, select one about half way up the height of the pile of
+lumber. If kiln-dried, two thirds the height of the kiln car. Do not
+remove the kiln car from the kiln until after the test. Three of four
+test pieces should be cut from near the middle of the cross-wise
+section of the board, and 1/8 to 3/16 inch thick. Remove the
+superfluous sawdust and splinters. When the test pieces are placed on
+the scale pan, be sure their weight is less than two ounces and more
+than 1-3/4 ounces. If necessary, use two or more broken pieces. It is
+better if the test pieces can be cut off on a fine band saw.
+
+=Weighing.=--Set the base of the scale on a level surface and accurately
+balance the scale beam. Put the test pieces on the scale pan and note
+their weight on the lower edge of the beam. Set the indicator point on
+the horizontal bar at a number corresponding to this weight, which may
+be found on the cylinder at the top of the table.
+
+Dry the test pieces on the Electric Heater (Fig. 101) 30 to 40
+minutes, or on the engine cylinder two or three hours. Weigh them at
+once and note the weight. Then turn the cylinder up and at the left of
+it under the small pointer find the number corresponding to this
+weight. The percentage of moisture lost is found directly under
+pointer on the horizontal bar first mentioned. The lower portion on
+the cylinder Table No. II is an extension of the upper portion, and
+is manipulated in the same manner except that the bottom line of
+figures is used for the first weight, and the right side of cylinder
+for second weight. Turn the cylinder down instead of up when using it.
+
+
+                        Examples (Test Pieces)
+
+     MODEL A. Table No. II, Kiln-dried or Air-dried Lumber:
+
+     If first weight is 90-1/2 and the second weight is 87, the
+     cylinder table will show the board from which the test
+     pieces were taken had a moisture content of 3.8 per cent.
+
+     MODEL B. Tables No. II and III, Air-dried (also Green and
+     Kiln-dried) Lumber.
+
+     If the first weight on lower cylinder is 97 and the second
+     weight is 76, the table will show 21.6 per cent of moisture.
+
+     MODEL C. Table III, Green Lumber:
+
+     If the first weight is 94 and the second weight is 51, the
+     table shows 45.8 per cent of moisture.
+
+
+                 Keep Records of the Moisture Content
+
+=Saw Mills.=--Should test and mark each pile of lumber when first piled
+in the yard, and later when sold it should be again tested and the two
+records given to the purchaser.
+
+=Factories.=--Should test and mark the lumber when first received, and
+if piled in the yard to be kiln-dried later, it should be tested
+before going into the dry kiln, and again before being removed, and
+these records placed on file for future reference.
+
+Kiln-dried lumber piled in storage rooms (without any heat) will
+absorb 7 to 9 per cent of moisture, and even when so stored should be
+tested for moisture before being manufactured into the finished
+product.
+
+Never work lumber through the factory that has more than 5 or 6 per
+cent of moisture or less than 3 per cent.
+
+Dry storage rooms should be provided with heating coils and properly
+ventilated.
+
+Oak or any other species of wood that shows 25 or 30 per cent of
+moisture when going into the dry kiln, will take longer to dry than it
+would if it contained 15 to 20 per cent, therefore the importance of
+testing before putting into the kiln as well as when taking it out.
+
+
+                          The Electric Heater
+
+In Figure 101 is shown the Electric Heater. This heater is especially
+designed to dry quickly the test pieces for use in connection with the
+Scalometer (see Fig. 100) without charring them. It may be attached to
+any electric light socket of 110 volts direct or alternating current.
+A metal rack is provided to hold the test pieces vertically on edge.
+
+    [Illustration: Fig. 101. The Electric Heater.]
+
+Turn the test pieces over once or twice while drying.
+
+It will require from 20 minutes to one hour to remove all the moisture
+from the test pieces when placed on this heater, depending on whether
+they are cut from green, air-dried, or kiln-dried boards.
+
+Test pieces cut from softwoods will dry quicker than those cut from
+hardwoods.
+
+When the test pieces fail to show any further loss in weight, they are
+then free from all moisture content.
+
+
+
+
+                             BIBLIOGRAPHY
+
+
+AMERICAN BLOWER COMPANY, Detroit, Mich.
+
+IMRE, JAMES E., "The Kiln-drying of Gum," The United States
+Dept. of Agriculture, Division of Forestry.
+
+NATIONAL DRY KILN COMPANY, Indianapolis, Ind.
+
+PRICHARD, REUBEN P., "The Structure of the Common Woods,"
+The United States Dept. of Agriculture, Division of Forestry,
+Bulletin No. 3.
+
+ROTH, FILIBERT, "Timber," The United States Dept. of Agriculture,
+Division of Forestry, Bulletin No. 10.
+
+STANDARD DRY KILN COMPANY, Indianapolis, Ind.
+
+STURTEVANT COMPANY, B. F., Boston, Mass.
+
+TIEMAN, H. D., "The Effects of Moisture upon the Strength and
+Stiffness of Wood," The United States Dept. of Agriculture,
+Division of Forestry, Bulletin No. 70.
+
+TIEMAN, H. D., "Principles of Kiln-drying Lumber," The United
+States Dept. of Agriculture, Division of Forestry.
+
+TIEMAN, H. D., "The Theory of Drying and its Application, etc.,"
+The United States Dept. of Agriculture, Division of Forestry,
+Bulletin No. 509.
+
+THE UNITED STATES DEPT. OF AGRICULTURE, DIVISION OF FORESTRY,
+"Check List of the Forest Trees of the United States."
+
+THE UNITED STATES DEPT. OF AGRICULTURE, DIVISION OF
+FORESTRY, Bulletin No. 37.
+
+VON SCHRENK, HERMAN, "Seasoning of Timbers," The United
+States Dept. of Agriculture, Division of Forestry, Bulletin
+No. 41.
+
+WAGNER, J. B., "Cooperage," 1910.
+
+
+
+
+                               GLOSSARY
+
+
+=Abnormal.= Differing from the usual structure.
+
+=Acuminate.= Tapering at the end.
+
+=Adhesion.= The union of members of different floral whorls.
+
+=Air-seasoning.= The drying of wood in the open air.
+
+=Albumen.=  A name applied to the food store laid up outside the
+embryo in many seeds; also nitrogenous organic matter found in plants.
+
+=Alburnam.= Sapwood.
+
+=Angiosperms.= Those plants which bear their seeds within a
+pericarp.
+
+=Annual rings.= The layers of wood which are added annually to
+the tree.
+
+=Apartment kiln.= A drying arrangement of one or more rooms
+with openings at each end.
+
+=Arborescent.= A tree in size and habit of growth.
+
+
+=Baffle plate.= An obstruction to deflect air or other currents.
+
+=Bastard cut.= Tangential cut. Wood of inferior cut.
+
+=Berry.= A fruit whose entire pericarp is succulent.
+
+=Blower kiln.= A drying arrangement in which the air is blown
+through heating coils into the drying room.
+
+=Box kiln.= A small square heating room with openings in one end
+only.
+
+=Brittleness.= Aptness to break; not tough; fragility.
+
+=Burrow.= A shelter; insect's hole in the wood.
+
+
+=Calorie.=  Unit of heat; amount of heat which raises the
+temperature.
+
+=Calyx.= The outer whorl of floral envelopes.
+
+=Capillary.= A tube or vessel extremely fine or minute.
+
+=Case-harden.= A condition in which the pores of the wood are
+closed and the outer surface dry, while the inner portion is
+still wet or unseasoned.
+
+=Cavity.= A hollow place; a hollow.
+
+=Cell.= One of the minute, elementary structures comprising the
+greater part of plant tissue.
+
+=Cellulose.= A primary cell-wall substance.
+
+=Checks.= The small chinks or cracks caused by the rupture of the
+wood fibres.
+
+=Cleft.= Opening made by splitting; divided.
+
+=Coarse-grained.= Wood is coarse-grained when the annual rings
+are wide or far apart.
+
+=Cohesion.= The union of members of the same floral whorl.
+
+=Contorted.= Twisted together.
+
+=Corolla.= The inner whorl of floral envelopes.
+
+=Cotyledon.= One of the parts of the embryo performing in part the
+function of a leaf, but usually serving as a storehouse of food
+for the developing plant.
+
+=Crossers.= Narrow wooden strips used to separate the material on
+kiln cars.
+
+=Cross-grained.= Wood is cross-grained when its fibres are spiral
+or twisted.
+
+
+=Dapple.= An exaggerated form of mottle.
+
+=Deciduous.= Not persistent; applied to leaves that fall in autumn
+and to calyx and corolla when they fall off before the fruit
+develops.
+
+=Definite.= Limited or defined.
+
+=Dew-point.= The point at which water is deposited from moisture-laden
+air.
+
+=Dicotyledon.= A plant whose embryo has two opposite cotyledons.
+
+=Diffuse.= Widely spreading.
+
+=Disk.= A circular, flat, thin piece or section of the tree.
+
+=Duramen.= Heartwood.
+
+
+=Embryo.= Applied in botany to the tiny plant within the seed.
+
+=Enchinate.= Beset with prickles.
+
+=Expansion.= An enlargement across the grain or lengthwise of the
+wood.
+
+
+=Fibres.= The thread-like portion of the tissue of wood.
+
+=Fibre-saturation point.= The amount of moisture wood will imbibe,
+usually 25 to 30 per cent of its dry-wood weight.
+
+=Figure.= The broad and deep medullary rays as in oak showing
+when the timber is cut into boards.
+
+=Filament.= The stalk which supports the anther.
+
+=Fine-grained.= Wood is fine-grained when the annual rings are
+close together or narrow.
+
+
+=Germination.= The sprouting of a seed.
+
+=Girdling.= To make a groove around and through the bark of a
+tree, thus killing it.
+
+=Glands.= A secreting surface or structure; a protuberance having
+the appearance of such an organ.
+
+=Glaucous.= Covered or whitened with a bloom.
+
+=Grain.= Direction or arrangement of the fibres in wood.
+
+=Grubs.= The larvae of wood-destroying insects.
+
+=Gymnosperms.= Plants bearing naked seeds; without an ovary.
+
+
+=Habitat.= The geographical range of a plant.
+
+=Heartwood.= The central portion of tree.
+
+=Hollow-horning.= Internal checking.
+
+=Honeycombing.= Internal checking.
+
+=Hot-blast kiln.= A drying arrangement in which the air is blown
+through heating coils into the drying room.
+
+=Humidity.= Damp, moist.
+
+=Hygroscopicity.= The property of readily imbibing moisture from
+the atmosphere.
+
+
+=Indefinite.= Applied to petals or other organs when too numerous
+to be conveniently counted.
+
+=Indigenous.= Native to the country.
+
+=Involute.= A form of vernation in which the leaf is rolled inward
+from its edges.
+
+
+=Kiln-drying.= Drying or seasoning of wood by artificial heat in an
+inclosed room.
+
+
+=Leaflet.= A single division of a compound leaf.
+
+=Limb.= The spreading portion of the tree.
+
+=Lumen.= Internal space in the spring- and summer-wood fibres.
+
+
+=Median.= Situated in the middle.
+
+=Medulla.= The pith.
+
+=Medullary rays.= Rays of fundamental tissue which connect the
+pith with the bark.
+
+=Membranous.= Thin and rather soft, more or less translucent.
+
+=Midrib.= The central or main rib of a leaf.
+
+=Moist-air kiln.= A drying arrangement in which the heat is taken
+from radiating coils located inside the drying room.
+
+=Mottle.= Figure transverse of the fibres, probably caused by the
+action of wind upon the tree.
+
+
+=Non-porous.= Without pores.
+
+
+=Oblong.= Considerably longer than broad, with flowing outline.
+
+=Obtuse.= Blunt, rounded.
+
+=Oval.= Broadly elliptical.
+
+=Ovary.= The part of the pistil that contains the ovules.
+
+
+=Parted.= Cleft nearly, but not quite to the base or midrib.
+
+=Parenchyma.= Short cells constituting the pith and pulp of the
+tree.
+
+=Pericarp.= The walls of the ripened ovary, the part of the fruit
+that encloses the seeds.
+
+=Permeable.= Capable of being penetrated.
+
+=Petal.= One of the leaves of the corolla.
+
+=Pinholes.= Small holes in the wood caused by worms or insects.
+
+=Pistil.= The modified leaf or leaves which bear the ovules; usually
+consisting of ovary, style and stigma.
+
+=Plastic.= Elastic, easily bent.
+
+=Pocket kilns.= Small drying rooms with openings on one end only
+and in which the material to be dried is piled directly on the
+floor.
+
+=Pollen.= The fertilizing powder produced by the anther.
+
+=Pores.= Minute orifices in wood.
+
+=Porous.= Containing pores.
+
+=Preliminary steaming.= Subjecting wood to a steaming process
+before drying or seasoning.
+
+=Progressive kiln.= A drying arrangement with openings at both
+ends, and in which the material enters at one end and is discharged
+at the other.
+
+
+=Rick.= A pile or stack of lumber.
+
+=Rift.= To split; cleft.
+
+=Ring shake.= A large check or crack in the wood following an
+annual ring.
+
+=Roe.= A peculiar figure caused by the contortion of the woody
+fibres, and takes a wavy line parallel to them.
+
+
+=Sapwood.= The outer portions of the tree next to the bark;
+alburnam.
+
+=Saturate.= To cause to become completely penetrated or soaked.
+
+=Season checks.= Small openings in the ends of the wood caused
+by the process of drying.
+
+=Seasoning.= The process by which wood is dried or seasoned.
+
+=Seedholes.= Minute holes in wood caused by wood-destroying
+worms or insects.
+
+=Shake.= A large check or crack in wood caused by the action of
+the wind on the tree.
+
+=Shrinkage.= A lessening or contraction of the wood substance.
+
+=Skidways.= Material set on an incline for transporting lumber or
+logs.
+
+=Species.= In science, a group of existing things, associated according
+to properties.
+
+=Spermatophyta.= Seed-bearing plants.
+
+=Spring-wood.= Wood that is formed in the spring of the year.
+
+=Stamen.= The pollen-bearing organ of the flower, usually consisting
+of filament and anther.
+
+=Stigma.= That part of the pistil which receives the pollen.
+
+=Style.= That part of the pistil which connects the ovary with the
+stigma.
+
+
+=Taproot.= The main root or downward continuation of the plant
+axis.
+
+=Temporary checks.= Checks or cracks that subsequently close.
+
+=Tissue.= One of the elementary fibres composing wood.
+
+=Thunder shake.= A rupture of the fibres of the tree across the
+grain, which in some woods does not always break them.
+
+=Tornado shake.= (See Thunder shake.)
+
+=Tracheids.= The tissues of the tree which consist of vertical cells
+or vessels closed at one end.
+
+
+=Warping.= Turning or twisting out of shape.
+
+=Wind shake.= (See Thunder shake.)
+
+=Working.= The shrinking and swelling occasioned in wood.
+
+=Wormholes.= Small holes in wood caused by wood-destroying
+worms.
+
+
+=Vernation.= The arrangement of the leaves in the bud.
+
+=Whorl.= An arrangement of organs in a circle about a central axis.
+
+
+
+
+                         INDEX OF LATIN NAMES
+
+
+Abies amabalis, 21
+Abies balsamea, 20
+Abies concolor, 20
+Abies grandis, 20
+Abies magnifica, 21
+Abies nobilis, 21
+Acer macrophyllum, 69
+Acer negundo, 69
+Acer Pennsylvanicum, 70
+Acer rubrum, 69
+Acer saccharinum, 69
+Acer saccharum, 68
+Acer spicatum, 69
+Æsculus flava, 45
+Æsculus glabra, 45
+Æsculus octandra, 45
+Ailanthus glandulosa, 37
+Asimina triloba, 76
+
+
+Betula lenta, 41
+Betula lutea, 42
+Betula nigra, 43
+Betula papyrifera, 43
+Betula populifolia, 42
+Betula rubra, 43
+Buxus sempervirens, 77
+
+
+Carpinus Caroliana, 44
+Castanea Americana, 48
+Castanea chrysophylla, 49
+Castanea dentata, 48
+Castanea pumila, 48
+Castanea vesca, 48
+Castanea vulgaris, 48
+Catalpa bignonioides, 46
+Catalpa speciosa, 46
+Celtis occidentalis, 62
+Chamæcyparis Lawsonia, 18
+Chamæcyparis thyoides, 17
+Cladrastis lutea, 85
+Cornus florida, 49
+Cupressus nootkatensis, 18
+
+
+Diospyros Virginia, 77
+
+
+Evonymus atropurpureus, 82
+
+
+Fagus ferruginea, 40
+Fraxinus Americana, 37
+Fraxinus Caroliniana, 39
+Fraxinus nigra, 38
+Fraxinus Oregana, 38
+Fraxinus Pennsylvanica, 38
+Fraxinus pubescens, 38
+Fraxinus quadrangulata, 38
+Fraxinus sambucifolia, 38
+Fraxinus viridis, 38
+
+
+Gleditschia triacanthos, 66
+Gymnocladus dioicus, 49
+
+
+Hicoria alba, 64
+Hicoria glabra, 64
+Hicoria minima, 64
+Hicoria ovata, 64
+Hicoria pecan, 64
+
+
+Ilex monticolo, 65
+Ilex opaca, 64
+
+
+Juglans cinerea, 45
+Juglans nigra, 82
+Juniperus communis, 19
+Juniperus Virginiana, 18
+
+
+Larix Americana, 22
+Larix laricina, 22
+Larix occidentalis, 22
+Libocedrus decurrens, 18
+Liquidamber styraciflua, 54
+Liriodendron tulipfera, 81
+
+
+Maclura aurantiaca, 76
+Magnolia acuminata, 67
+Magnolia glauca, 67
+Magnolia tripetala, 67
+Morus rubra, 70
+
+
+Nyssa aquatica, 60
+Nyssa sylvatica, 62
+
+
+Ostrya Virginiana, 65
+Oxydendrum arboreum, 80
+
+
+Picea alba, 28
+Picea canadensis, 28
+Picea engelmanni, 28
+Picea mariana, 27
+Picea nigra, 27
+Picea rubens, 28
+Picea sitchensis, 28
+Pinus banksiana, 27
+Pinus cubensis, 26
+Pinus divaricata, 27
+Pinus enchinata, 26
+Pinus flexilis, 24
+Pinus inops, 27
+Pinus Jeffreyi, 25
+Pinus Lambertiana, 24
+Pinus monticolo, 24
+Pinus Murryana, 27
+Pinus palustris, 24
+Pinus ponderosa, 25
+Pinus resinosa, 25
+Pinus rigida, 26
+Pinus strobus, 23
+Pinus tæda, 25
+Pinus Virginiana, 27
+Platanus occidentalis, 80
+Platanus racemosa, 81
+Populus alba, 79
+Populus angulata, 77
+Populus balsamifera, 79
+Populus fremontii, 78
+Populus grandidentata, 79
+Populus heteropylla, 78
+Populus monilifera, 77
+Populus nigra italica, 79
+Populus tremuloides, 79
+Populus trichocarpa, 78
+Populus Wislizeni, 78
+Prunus Pennsylvanica, 47
+Prunus serotina, 47
+Pseudotsuga douglasii, 29
+Pseudotsuga taxifolia, 29
+Pyrus coronaria, 49
+
+
+Quercus acuminata, 73
+Quercus alba, 71
+Quercus aquatica, 73
+Quercus bicolor, 72
+Quercus chrysolepis, 76
+Quercus coccinea, 75
+Quercus digitata, 75
+Quercus durandii, 71
+Quercus falcata, 75
+Quercus garryana, 71
+Quercus ilicijolia, 74
+Quercus imbricaria, 75
+Quercus lobata, 72
+Quercus lyrata, 73
+Quercus macrocarpa, 72
+Quercus marilandica, 75
+Quercus Michauxii, 74
+Quercus minor, 74
+Quercus nigra, 75
+Quercus obtusiloda, 74
+Quercus palustris, 73
+Quercus phellos, 72
+Quercus platanoides, 72
+Quercus prinoides, 74
+Quercus prinus, 73
+Quercus pumila, 74
+Quercus rubra, 74
+Quercus tinctoria, 74
+Quercus velutina, 74
+Quercus virens, 75
+
+
+Rhamnus Caroliniana, 45
+Robinia pseudacacia, 66
+Robinia viscosa, 66
+
+
+Salix alba, 83
+Salix amygdaloides, 84
+Salix babylonica, 84
+Salix bebbiana, 84
+Salix discolor, 84
+Salix fluviatilis, 84
+Salix fragilis, 84
+Salix lucida, 84
+Salix nigra, 83
+Salix rostrata, 84
+Salix vitellina, 83
+Sassafras sassafras, 80
+Sequoia sempervirens, 19
+
+
+Taxodium distinchum, 19
+Taxus brevifolia, 30
+Thuya gigantea, 17
+Thuya occidentalis, 17
+Tilia Americana, 39
+Tilia heterophylla, 39
+Tilia pubescens, 39
+Tsuga canadensis, 21
+Tsuga mertensiana, 21
+
+
+Ulmus alata, 51
+Ulmus Americana, 50
+Ulmus crassifolia, 51
+Ulmus fulva, 51
+Ulmus pubescens, 51
+Ulmus racemosa, 50
+Umbellularia Californica, 65
+
+
+
+
+                                 INDEX
+
+
+Abele, Tree, 79
+
+Absorption of water by dry wood, 124
+
+Acacia, 66
+
+Acacia, false, 66
+
+Acacia, three-thorned, 66
+
+According to species, different kiln drying, 170
+
+Advantages in seasoning, 128
+
+Advantages of kiln-drying over air-drying, 156
+
+Affect drying, properties of wood that, 156
+
+Ailanthus, 37
+
+Air circulation, 173
+
+Air-drying, advantages of kiln-drying over, 156
+
+Alaska cedar, 18
+
+Alaska cypress, 18
+
+Alcoholic liquids, stave and heads of barrels containing, 112
+
+Almond-leaf willow, 84
+
+Ambrosia or timber beetles, 99
+
+American box, 49
+
+American elm, 50
+
+American larch, 22
+
+American linden, 39
+
+American oak, 71
+
+American red pine, 25
+
+Anatomical structure, 14
+
+Annual ring, the yearly or, 10
+
+Apartment dry kiln, 198
+
+Apple, crab, 49
+
+Apple, custard, 76
+
+Apple, wild, 49
+
+Appliances in kiln-drying, helpful, 237
+
+Arborvitæ, 17
+
+Ash, 37
+
+Ash, black, 38
+
+Ash, blue, 38
+
+Ash, Carolina, 39
+
+Ash, green, 38
+
+Ash, ground, 38
+
+Ash, hoop, 38
+
+Ash-leaved maple, 69
+
+Ash, Oregon, 38
+
+Ash, red, 38
+
+Ash, white, 37
+
+Aspen, 39, 79
+
+Aspen, large-toothed, 78
+
+Aspen-leaved birch, 42
+
+Aspen, quaking, 79
+
+Atmospheric pressure, drying at, 146
+
+
+Bald Cypress, 19
+
+Ball tree, button, 80
+
+Balm of gilead, 79
+
+Balm of gilead fir, 20
+
+Balsam, 20, 79
+
+Balsam fir, 20
+
+Bark and pith, 8
+
+Bark on, round timber with, 106
+
+Barrels containing alcoholic liquids, staves and heads of, 112
+
+Barren oak, 75
+
+Bar willow, sand, 84
+
+Basket oak, 74
+
+Basswood, 39
+
+Basswood, small-leaved, 39
+
+Basswood, white, 39
+
+Bastard pine, 26
+
+Bastard spruce, 29
+
+Bay poplar, 60
+
+Bay, sweet, 67
+
+Bear oak, 74
+
+Beaver wood, 67
+
+Bebb willow, 84
+
+Bee tree, 39
+
+Beech, 40
+
+Beech, blue, 44
+
+Beech, red, 40
+
+Beech, water, 44, 80
+
+Beech, white, 40
+
+Berry, sugar, 62
+
+Beetles, ambrosia or timber, 99
+
+Big bud hickory, 64
+
+Bilsted, 54
+
+Birch, 41
+
+Birch, aspen-leaved, 42
+
+Birch, black, 41
+
+Birch, canoe, 43
+
+Birch, cherry, 41
+
+Birch, gray, 42
+
+Birch, mahogany, 41
+
+Birch, old field, 42
+
+Birch, paper, 43
+
+Birch, red, 42
+
+Birch, river, 43
+
+Birch, silver, 42
+
+Birch, sweet, 41
+
+Birch, white, 42, 43
+
+Birch, wintergreen, 41
+
+Birch, yellow, 42
+
+Bird cherry, 47
+
+Bitternut hickory, 64
+
+Black ash, 38
+
+Black birch, 41
+
+Black cherry, 47
+
+Black cottonwood, 78
+
+Black cypress, 19
+
+Black gum, 62
+
+Black hickory, 64
+
+Black jack, 75
+
+Black larch, 22
+
+Black locust, 66
+
+Black nut hickory, 64
+
+Black oak, 74
+
+Black pine, 25, 27
+
+Black spruce, 27
+
+Black walnut, 44, 82
+
+Black willow, 83
+
+Blower dry kiln, operation of, 186
+
+Blower or hot blast dry kiln, 185
+
+Blue ash, 38
+
+Blue beech, 44
+
+Blue poplar, 81
+
+Blue willow, 83
+
+Bois d'Arc, 45, 76
+
+Bolts, stave, heading and shingle, 109
+
+Borers, flat-headed, 103
+
+Borers, powder post, 105
+
+Borers, round-headed, 101
+
+Box, American, 49
+
+Box elder, 69
+
+Box dry kiln, 204
+
+Broad-leaved maple, 69
+
+Broad-leaved trees, 31
+
+Broad-leaved trees, list of most important, 37
+
+Broad-leaved trees, wood of, 31
+
+Brown hickory, 64
+
+Brown locust, 66
+
+Buckeye, 45
+
+Buckeye, fetid, 45
+
+Buckeye, Ohio, 45
+
+Buckeye, sweet, 45
+
+Buckthorne, 45
+
+Bud hickory, big, 64
+
+Bull nut hickory, 64
+
+Bull pine, 25
+
+Bur oak, 72
+
+Burning bush, 82
+
+Bush, burning, 82
+
+Bush, juniper, 18
+
+Butternut, 45
+
+Button ball tree, 80
+
+Button wood, 80
+
+
+California Redwood, 19
+
+California white pine, 25
+
+Canadian pine, 25
+
+Canary wood, 81
+
+Canoe birch, 43
+
+Canoe cedar, 17
+
+Carolina ash, 39
+
+Carolina pine, 26
+
+Carolina poplar, 77
+
+Cars, method of loading kiln, 206
+
+Catalpa, 46
+
+Cedar, 17
+
+Cedar, Alaska, 18
+
+Cedar, canoe, 17
+
+Cedar, elm, 51
+
+Cedar, ground, 19
+
+Cedar, incense, 18
+
+Cedar of the West, red, 17
+
+Cedar, Oregon, 18
+
+Cedar, pencil, 18
+
+Cedar, Port Orford, 18
+
+Cedar, red, 18, 19
+
+Cedar, white, 17, 18
+
+Cedar, yellow, 18
+
+Changes rendering drying difficult, 140
+
+Characteristics and properties of wood, 1
+
+Checking and splitting, prevention of, 129
+
+Cherry, 47
+
+Cherry birch, 41
+
+Cherry, bird, 47
+
+Cherry, black, 47
+
+Cherry, Indian, 45
+
+Cherry, red, 47
+
+Cherry, rum, 47
+
+Cherry, wild, 47
+
+Cherry, wild red, 47
+
+Chestnut, 48
+
+Chestnut, horse, 45, 65
+
+Chestnut oak, 73
+
+Chestnut oak, rock, 73
+
+Chestnut oak, scrub, 74
+
+Chinquapin, 48, 49
+
+Chinquapin oak, 73, 74
+
+Chinquapin oak, dwarf, 74
+
+Choice of drying method, 195
+
+Circassian walnut, 60
+
+Circulation, air, 173
+
+Clammy locust, 66
+
+Classes of trees, 5
+
+Cliff elm, 50
+
+Coast redwood, 19
+
+Coffee nut, 49
+
+Coffee tree, 49
+
+Color and odor of wood, 89
+
+Color, odor, weight, and figure in wood, grain, 86
+
+Composition of sap, 116
+
+Conditions and species, temperature depends on, 171
+
+Conditions favorable for insect injury, 106
+
+Conditions governing the drying of wood, 156
+
+Conditions of success in kiln-drying, 169
+
+Coniferous trees, 8
+
+Coniferous trees, wood of, 8
+
+Coniferous woods, list of important, 17
+
+Containing alcoholic liquids, staves and heads of barrels, 112
+
+Cooperage stock and wooden truss hoops, dry, 112
+
+Cork elm, 50
+
+Cotton gum, 60
+
+Cottonwood, 49, 77, 78
+
+Cottonwood, black, 78
+
+Cottonwood, swamp, 78
+
+Cow oak, 74
+
+Crab apple, 49
+
+Crab, fragrant, 49
+
+Crack willow, 84
+
+Crude products, 106
+
+Cuban pine, 26
+
+Cucumber tree, 49, 67
+
+Cup oak, mossy, 72
+
+Cup oak, over-, 72, 73
+
+Custard apple, 76
+
+Cypress, 19
+
+Cypress, Alaska, 18
+
+Cypress, bald, 19
+
+Cypress, black, 19
+
+Cypress, Lawson's, 18
+
+Cypress, pecky, 19
+
+Cypress, red, 19
+
+Cypress, white, 19
+
+
+D'Arc, Bois, 45, 76
+
+Deal, yellow, 23
+
+Demands upon soil and moisture of red gum, 56
+
+Depends on conditions and species, temperature, 171
+
+Description of the forest service kiln, theory and, 161
+
+Diagram, the uses of the humidity, 237
+
+Difference between seasoned and unseasoned wood, 121
+
+Different grains of wood, 86
+
+Different kiln-drying according to species, 170
+
+Different species, weight of kiln-dried wood of, 95
+
+Different types, kilns of, 196
+
+Different types of dry kilns, 185
+
+Different types of kiln doors, 231
+
+Difficult, changes rendering drying, 140
+
+Difficulties of drying wood, 138
+
+Distribution of water in wood, 114
+
+Distribution of water in wood, local, 114
+
+Distribution of water in wood seasonal, 115
+
+Dogwood, 49
+
+Doors, different types of kiln, 231
+
+Douglas spruce, 29
+
+Downy linden, 39
+
+Downy poplar, 78
+
+Dry cooperage stock and wooden truss hoops, 112
+
+Drying according to species, different kiln, 170
+
+Drying, advantages of kiln-drying over air, 156
+
+Drying at atmospheric pressure, 146
+
+Drying by superheated steam, 150
+
+Drying, conditions of success in kiln, 169
+
+Drying difficult, changes rendering, 140
+
+Drying gum, kiln, 180
+
+Drying, helpful appliances in kiln, 237
+
+Drying, kiln, 164, 177
+
+Drying, losses due to improper kiln, 141
+
+Drying method, choice of, 185
+
+Drying, methods of kiln, 145
+
+Drying, objects of kiln, 168
+
+Drying of green red gum, kiln, 183
+
+Drying of wood, kiln, 156
+
+Drying of wood, physical conditions governing the, 156
+
+Drying, physical properties that influence, 125
+
+Drying, properties of wood that effect, 141
+
+Drying, theory of kiln, 157
+
+Drying, underlying principles of kiln, 166
+
+Drying under pressure and vacuum, 146
+
+Drying, unsolved problems in kiln, 143
+
+Drying wood, difficulties of, 138
+
+Drying 100 lb. of green wood in the kiln, pounds of water lost, 179
+
+Dry kiln, apartment, 198
+
+Dry kiln, box, 204
+
+Dry kiln, operation of the blower, 186
+
+Dry kiln, operation of the moist-air, 192
+
+Dry kiln, moist-air or pipe, 188
+
+Dry kiln, pocket, 200
+
+Dry kiln, progressive, 196
+
+Dry kiln, requirements in a satisfactory, 160
+
+Dry kilns, different types of, 185
+
+Dry kiln specialties, 206
+
+Dry kilns, types of, 185
+
+Dry kiln, tower, 202
+
+Dry wood, absorption of water by, 124
+
+Duck oak, 73
+
+Due to improper kiln-drying, losses, 141
+
+Dwarf chinquapin oak, 74
+
+
+Effects of Moisture on Wood, 117
+
+Elder, box, 69
+
+Electric heater, the, 250
+
+Elimination of stain and mildew, 136
+
+Elm, 50
+
+Elm, American, 50
+
+Elm, cedar, 51
+
+Elm, cliff, 50
+
+Elm, cork, 50
+
+Elm, hickory, 50
+
+Elm, moose, 51
+
+Elm, red, 51
+
+Elm, rock, 50
+
+Elm, slippery, 51
+
+Elm, water, 50
+
+Elm, winged, 51
+
+Elm, white, 50
+
+Enemies of wood, 98
+
+Evaporation of water, manner of, 123
+
+Evaporation, rapidity of, 124
+
+Expansion of wood, 135
+
+
+Factories, Scalometer in, 249
+
+False acacia, 66
+
+Favorable for insect injury, conditions, 106
+
+Fetid buckeye, 45
+
+Fibre saturation point in wood, 118
+
+Field birch, old, 42
+
+Field pine, old, 25, 26
+
+Figure in wood, 96
+
+Figure in wood, grain, color, odor, weight, and, 86
+
+Final steaming of gum, 182
+
+Fir, 20
+
+Fir, balm of gilead, 20
+
+Fir balsam, 20
+
+Fir, noble, 21
+
+Fir, red, 21, 29
+
+Fir tree, 20
+
+Fir, white, 20, 21
+
+Fir, yellow, 29
+
+Flat-headed borers, 103
+
+Forest service kiln, theory and description of, 161
+
+Form of the red gum, 55
+
+Fragrant crab, 49
+
+
+Gauge, the Recording Steam, 246
+
+Georgia pine, 24
+
+Gilead, balm of, 79
+
+Gilead fir, balm of, 20
+
+Ginger pine, 18
+
+Glaucous willow, 84
+
+Governing the drying of wood, physical conditions, 156
+
+Grain, color, odor, weight, and figure in wood, 86
+
+Grains of wood, different, 86
+
+Gray birch, 42
+
+Gray pine, 27
+
+Green ash, 38
+
+Green red gum, kiln-drying, 183
+
+Green wood in the kiln, pounds of water lost in drying 100 lbs., 179
+
+Ground ash, 38
+
+Ground cedar, 19
+
+Growth red gum, second, 59
+
+Gum, 52
+
+Gum, black, 62
+
+Gum, cotton, 60
+
+Gum, demands upon soil and moisture of red, 56
+
+Gum, final steaming of, 182
+
+Gum, form of red, 55
+
+Gum, kiln-drying, 180
+
+Gum, kiln-drying of green red, 183
+
+Gum, method of piling, 180
+
+Gum, preliminary steaming of, 182
+
+Gum, range of red, 55
+
+Gum, range of tupelo, 61
+
+Gum, red, 54, 79
+
+Gum, reproduction of red, 57
+
+Gum, second-growth red, 59
+
+Gum, sour, 62, 80
+
+Gum, sweet, 54, 80
+
+Gum, tolerance of the red, 56
+
+Gum, tupelo, 60
+
+Gum, uses of tupelo, 61
+
+
+Hackberry, 62
+
+Hacmatac, 22
+
+Hard maple, 68
+
+Hard pine, 26
+
+Hard pines, 24
+
+Hard pine, southern, 24
+
+Hardwoods, 37
+
+Hazel pine, 54, 60
+
+Headed borers, flat, 103
+
+Headed borers, round, 101
+
+Heading, stave and shingle bolts, 109
+
+Heads and staves of barrels containing alcoholic liquids, 112
+
+Heart hickory, white, 64
+
+Heartwood, sap and, 8
+
+Heater, the electric, 250
+
+Helpful appliances in kiln-drying, 237
+
+Hemlock, 21
+
+Hemlock spruce, 21
+
+Hickory, 63
+
+Hickory, big bud, 64
+
+Hickory, bitternut, 64
+
+Hickory, black, 64
+
+Hickory, black nut, 64
+
+Hickory, brown, 64
+
+Hickory, bull nut, 64
+
+Hickory elm, 50
+
+Hickory, mockernut, 64
+
+Hickory, pignut, 64
+
+Hickory, poplar, 81
+
+Hickory, scalybark, 64
+
+Hickory, shagbark, 64
+
+Hickory, shellbark, 64
+
+Hickory, swamp, 64
+
+Hickory, switchbud, 64
+
+Hickory, white heart, 64
+
+Holly, 64, 65
+
+Holly, mountain, 65
+
+Honey locust, 66
+
+Honey shucks, 66
+
+Hoop ash, 38
+
+Hoops, dry cooperage stock and wooden truss, 112
+
+Hop hornbeam, 65
+
+Hornbeam, 44
+
+Hornbeam, hop, 65
+
+Horse chestnut, 45, 65
+
+Hot blast or blower kiln, 185
+
+Humidity, 174
+
+Humidity diagram, uses of the, 237
+
+How to prevent insect injury, 107
+
+How wood is seasoned, 145
+
+Hygrodeik, the, 242
+
+Hygrometer, the recording, 242
+
+Hygrometer, the registering, 244
+
+
+Illinois Nut, 64
+
+Important broad-leaved trees, list of most, 37
+
+Important coniferous woods, list of, 17
+
+Impregnation methods, 151
+
+Improper kiln-drying, losses due to, 141
+
+Incense cedar, 18
+
+Indian bean, 46
+
+Indian cherry, 45
+
+Influence drying, physical properties that, 125
+
+Injury, conditions favorable for insect, 106
+
+Injury from insects, how to prevent, 107
+
+Insect injury, conditions favorable for, 106
+
+Insects, how to prevent injury from, 107
+
+Iron oak, 74
+
+Ironwood, 44, 65
+
+
+Jack, Black, 75
+
+Jack oak, 75
+
+Jack pine, 27
+
+Jersey pine, 27
+
+Juniper, 18
+
+Juniper bush, 18
+
+Juniper, red, 18
+
+Juniper, savin, 18
+
+
+Keep Records of the Moisture Content, 249
+
+Kiln, apartment dry, 198
+
+Kiln, blower or hot blast, 185
+
+Kiln, box dry, 204
+
+Kiln cars and method of loading, 206
+
+Kiln doors, different types, 231
+
+Kiln-dried wood of different species, weight of, 95
+
+Kiln-drying, 164, 177
+
+Kiln-drying according to species, different, 170
+
+Kiln-drying, conditions of success in, 169
+
+Kiln-drying gum, 180
+
+Kiln-drying, helpful appliances in, 237
+
+Kiln-drying, losses due to improper, 141
+
+Kiln-drying, objects of, 168
+
+Kiln-drying of green red gum, 183
+
+Kiln-drying of wood, 156
+
+Kiln-drying of wood, 156
+
+Kiln-drying over air-drying, advantages of, 156
+
+Kiln-drying, theory of, 157
+
+Kiln-drying, underlying principles of, 166
+
+Kiln-drying, unsolved problems in, 143
+
+Kiln, operation of the blower dry, 186
+
+Kiln, operation of the moist-air dry, 192
+
+Kiln, pipe or moist-air dry, 188
+
+Kiln, pocket dry, 200
+
+Kiln, progressive dry, 196
+
+Kiln, requirements in a satisfactory dry, 160
+
+Kilns, different types of dry, 185
+
+Kilns of different types, 196
+
+Kiln specialties, dry, 206
+
+Kiln, theory and description of the forest service, 161
+
+Kilns, types of dry, 185
+
+Kiln, tower dry, 202
+
+
+Land Spruce, Tide, 28
+
+Larch, 22
+
+Larch, American, 22
+
+Larch, black, 22
+
+Larch, western, 22
+
+Large-toothed aspen, 79
+
+Laurel, 65
+
+Laurel oak, 75
+
+Lawson's cypress, 18
+
+Leaf pine, long-, 24
+
+Leaf pine, short-, 26
+
+Leaf willow, long, 84
+
+Leaved basswood, small, 39
+
+Leaved birch, aspen, 42
+
+Leaved maple, ash, 69
+
+Leaved maple, broad, 69
+
+Leaved maple, silver, 69
+
+Leaved trees, broad, 31
+
+Leaved trees, list of most important broad, 37
+
+Leaved trees, wood of broad, 31
+
+Leverwood, 65
+
+Life, tree of, 17
+
+Lime tree, 39
+
+Lin, 39
+
+Linden, 39
+
+Linden, American, 39
+
+Linden, downy, 39
+
+Liquidamber, 54
+
+Liquids, staves and heads of barrels containing alcoholic, 112
+
+List of important coniferous trees, 17
+
+List of most important broad-leaved trees, 37
+
+Live oak, 75, 76
+
+Loading, kiln cars and method of, 206
+
+Loblolly pine, 25
+
+Local distribution of water in wood, 114
+
+Locust, 66
+
+Locust, black, 66
+
+Locust, brown, 66
+
+Locust, clammy, 66
+
+Locust, honey, 66
+
+Locust, sweet, 66
+
+Locust, yellow, 66
+
+Lodge-pole pine, 27
+
+Lombardy poplar, 79
+
+Long-leaf pine, 24
+
+Long-leaf willow, 84
+
+Long-straw pine, 24
+
+Losses due to improper kiln-drying, 141
+
+Lost in kiln-drying 100 lb. green wood in the kiln, pounds of water, 179
+
+
+Magnolia, 67
+
+Magnolia, small, 67
+
+Magnolia, swamp, 67
+
+Mahogany, birch, 41
+
+Mahogany, white, 45
+
+Manner of evaporation of water, 123
+
+Maple, 67
+
+Maple, ash-leaved, 69
+
+Maple, broad-leaved, 69
+
+Maple, hard, 68
+
+Maple, mountain, 69
+
+Maple, Oregon, 69
+
+Maple, red, 69
+
+Maple, rock, 68
+
+Maple, silver, 69
+
+Maple, silver-leaved, 69
+
+Maple, soft, 69
+
+Maple, striped, 70
+
+Maple, sugar, 68
+
+Maple, swamp, 69
+
+Maple, water, 69
+
+Maple, white, 69
+
+Maul oak, 75, 76
+
+Meadow pine, 26
+
+Method, choice of drying, 195
+
+Method of loading kiln cars, 206
+
+Method of piling gum, 180
+
+Methods, impregnation, 151
+
+Methods of drying, 154
+
+Mildew, elimination of stain and, 136
+
+Minute structure, 34
+
+Mockernut hickory, 64
+
+Moist-air dry kiln, operation of, 192
+
+Moist-air or pipe kiln, the, 188
+
+Moisture content, keep records of the, 249
+
+Moisture, demands upon soil and, 56
+
+Moisture on wood, effects of, 117
+
+Moose elm, 51
+
+Moose-wood, 70
+
+Mossy-cup oak, 72
+
+Most important broad-leaved trees list of, 37
+
+Mountain holly, 65
+
+Mountain maple, 69
+
+Mulberry, 70
+
+Mulberry, red, 70
+
+Myrtle, 65, 70
+
+
+Nettle Tree, 62
+
+Noble fir, 21
+
+Norway pine, 25
+
+Nut, coffee, 49
+
+Nut hickory, black, 64
+
+Nut hickory, bull, 64
+
+Nut, Illinois, 64
+
+Nyssa, 60
+
+
+Oak, 70
+
+Oak, American, 71
+
+Oak, barren, 75
+
+Oak, basket, 74
+
+Oak, bear, 74
+
+Oak, black, 74
+
+Oak, bur, 72
+
+Oak, chestnut, 73
+
+Oak, chinquapin, 73, 74
+
+Oak, cow, 74
+
+Oak, duck, 73
+
+Oak, dwarf chinquapin, 74
+
+Oak, iron, 74
+
+Oak, jack, 75
+
+Oak, laurel, 75
+
+Oak, live, 75, 76
+
+Oak, maul, 75, 76
+
+Oak, mossy-cup, 72
+
+Oak, over-cup, 72, 73
+
+Oak, peach, 72
+
+Oak, pin, 73
+
+Oak, possum, 73
+
+Oak, post, 74
+
+Oak, punk, 73
+
+Oak, red, 74, 75
+
+Oak, rock, 73
+
+Oak, rock chestnut, 73
+
+Oak, scarlet, 75
+
+Oak, scrub, 74
+
+Oak, scrub chestnut, 74
+
+Oak, shingle, 75
+
+Oak, Spanish, 75
+
+Oak, swamp post, 73
+
+Oak, swamp Spanish, 73
+
+Oak, swamp white, 72, 73
+
+Oak, water, 73
+
+Oak, western white, 71
+
+Oak, white, 71, 72
+
+Oak, willow, 72
+
+Oak, yellow, 73, 74
+
+Oak, Valparaiso, 76
+
+Objects of kiln-drying, 168
+
+Odor and color of wood, 89
+
+Odor, weight, and figure in wood, grain, color, 86
+
+Ohio buckeye, 45
+
+Old field birch, 42
+
+Old field pine, 25, 26
+
+Operation of the blower kiln, 186
+
+Operation of the moist-air kiln, 192
+
+Orange, osage, 76
+
+Oregon ash, 38
+
+Oregon cedar, 18
+
+Oregon maple, 69
+
+Oregon pine, 29
+
+Orford cedar, Port, 18
+
+Osage orange, 76
+
+Out-of-door seasoning, 154
+
+Over-cup oak, 72, 73
+
+
+Papaw, 76
+
+Paper birch, 43
+
+Peach oak, 72
+
+Pecan, 64
+
+Pecky cypress, 19
+
+Pencil cedar, 18
+
+Pepperidge, 60
+
+Perch willow, 84
+
+Persimmon, 77
+
+Peruche, 21
+
+Physical conditions governing the drying of wood, 156
+
+Physical properties that influence drying, 125
+
+Pignut hickory, 64
+
+Piling gum, methods of, 180
+
+Pine, American red, 25
+
+Pine, bastard, 26
+
+Pine, black, 25, 27
+
+Pine, bull, 25
+
+Pine, California white, 25
+
+Pine, Canadian, 25
+
+Pine, Carolina, 26
+
+Pine, Cuban, 26
+
+Pine, Georgia, 24
+
+Pine, ginger, 18
+
+Pine, gray, 27
+
+Pine, hard, 26
+
+Pine, hazel, 54, 60
+
+Pine, jack, 27
+
+Pine, Jersey, 27
+
+Pine, loblolly, 25
+
+Pine, lodge-pole, 27
+
+Pine, long-leaf, 24
+
+Pine, long-straw, 24
+
+Pine, meadow, 26
+
+Pine, Norway, 25
+
+Pine, old field, 25, 26
+
+Pine, Oregon, 29
+
+Pine, pitch, 26
+
+Pine, Puget Sound, 29
+
+Pine, pumpkin, 23, 24
+
+Pine, red, 29
+
+Pine, rosemary, 25
+
+Pine, sap, 25
+
+Pine, scrub, 27
+
+Pines, hard, 24
+
+Pine, short-leaf, 26
+
+Pine, short-straw, 25
+
+Pine, slash, 25, 26
+
+Pine, soft, 23, 24
+
+Pine, southern, 24
+
+Pine, southern hard, 24
+
+Pine, spruce, 26
+
+Pine, sugar, 24
+
+Pine, swamp, 26
+
+Pine, torch, 26
+
+Pine, Weymouth, 23
+
+Pine, western, 25
+
+Pine, western white, 25
+
+Pine, western yellow, 25
+
+Pine, white, 23, 24
+
+Pine, yellow, 24, 25, 26
+
+Pin oak, 73
+
+Pipe or moist-air kiln, 188
+
+Pitch pine, 26
+
+Pith and bark, 8
+
+Plane tree, 80
+
+Pocket dry kiln, the, 200
+
+Point in wood, the fibre saturation, 118
+
+Pole pine, lodge, 27
+
+Poplar, 67, 77, 79, 81
+
+Poplar, bay, 60
+
+Poplar, blue, 81
+
+Poplar, Carolina, 77
+
+Poplar, downy, 78
+
+Poplar, hickory, 81
+
+Poplar, Lombardy, 79
+
+Poplar, swamp, 60
+
+Poplar, white, 79, 81
+
+Poplar, yellow, 81
+
+Port Orford cedar, 18
+
+Possum oak, 73
+
+Post borers, powder, 105
+
+Post oak, 74
+
+Post oak, swamp, 73
+
+Pounds of water lost in drying 100 lb. green wood in the kiln, 179
+
+Powder post borers, 105
+
+Preliminary steaming of gum, 182
+
+Preliminary treatments, 151
+
+Pressure and vacuum, drying under, 146
+
+Pressure, drying at atmospheric, 146
+
+Prevent injury from insects, how to, 107
+
+Prevention of checking and splitting, 129
+
+Principles of kiln-drying, underlying, 166
+
+Problems in kiln-drying, unsolved, 143
+
+Products, crude, 106
+
+Products in the rough, seasoned, 112
+
+Products in the rough, unseasoned, 109
+
+Progressive dry kiln, the, 196
+
+Properties, characteristics and, 1
+
+Properties of wood, 4
+
+Properties of wood that affect drying, 141
+
+Properties that influence drying, physical, 125
+
+Puget Sound pine, 29
+
+Pumpkin pine, 23, 24
+
+Punk oak, 73
+
+Pussy willow, 84
+
+
+Quaking Aspen, 79
+
+
+Range of Red Gum, 55
+
+Range of tupelo gum, 61
+
+Rapidity of evaporation, 124
+
+Recording hygrometer, the, 242
+
+Recording steam gauge, the, 246
+
+Recording thermometer, the, 245
+
+Records of the moisture content, keep, 249
+
+Red ash, 38
+
+Red beech, 40
+
+Red birch, 43
+
+Red cedar, 18, 19
+
+Red cedar of the West, 17
+
+Red cherry, 47
+
+Red cherry, wild, 47
+
+Red cypress, 19
+
+Red elm, 51
+
+Red fir, 21, 29
+
+Red gum, 54, 79
+
+Red gum, demands upon soil and moisture of, 56
+
+Red gum, form of the, 55
+
+Red gum, kiln-drying of green, 183
+
+Red gum, range of, 55
+
+Red gum, reproduction of, 57
+
+Red gum, second-growth, 59
+
+Red gum, tolerance of, 56
+
+Red juniper, 18
+
+Red maple, 69
+
+Red mulberry, 70
+
+Red oak, 74, 75
+
+Red pine, 29
+
+Red pine, American, 25
+
+Red spruce, 28
+
+Redwood, 19, 27
+
+Redwood, California, 19
+
+Redwood, Coast, 19
+
+Registering hygrometer, the, 244
+
+Registering thermometer, the, 246
+
+Rendering drying difficult, changes, 140
+
+Reproduction of red gum, 57
+
+Requirements in a satisfactory dry kiln, 160
+
+Ring, the annual or yearly, 10
+
+River birch, 43
+
+Rock chestnut oak, 73
+
+Rock elm, 50
+
+Rock maple, 68
+
+Rock oak, 73
+
+Rosemary pine, 25
+
+Rough, seasoned products in the, 112
+
+Rough, unseasoned products in the, 109
+
+Round-headed borers, 101
+
+Round timber with bark on, 106
+
+Rum cherry, 47
+
+
+Samples for Scalometer Test, 248
+
+Sand bar willow, 84
+
+Sap and heartwood, 8
+
+Sap, composition of, 116
+
+Saplings, 108
+
+Sap pine, 25
+
+Sassafras, 80
+
+Satin walnut, 54
+
+Satisfactory dry kiln, requirements in a, 160
+
+Saturation point in wood, fibre, 118
+
+Sawmills, scalometer in, 249
+
+Savin juniper, 18
+
+Scalometer in factories, 249
+
+Scalometer in sawmills, 249
+
+Scalometer, test samples for, 248
+
+Scalometer, the troemroid, 247
+
+Scalometer, weighing with, 248
+
+Scalybark hickory, 64
+
+Scarlet oak, 75
+
+Scrub chestnut oak, 74
+
+Scrub oak, 74
+
+Scrub pine, 27
+
+Seasonal distribution of water in wood, 115
+
+Seasoned and unseasoned wood, difference between, 121
+
+Seasoned, how wood is, 145
+
+Seasoned products in the rough, 112
+
+Seasoning, advantages in, 128
+
+Seasoning is, what, 119
+
+Seasoning, out-of-door, 154
+
+Second-growth red gum, 59
+
+Sequoia, 19
+
+Service kiln, theory and description of forest, 161
+
+Shagbark hickory, 64
+
+Shellbark hickory, 64
+
+Shingle, heading and stave bolts, 109
+
+Shingle oak, 75
+
+Shining willow, 84
+
+Short-leaf pine, 26
+
+Short-straw pine, 25
+
+Shrinkage of wood, 130
+
+Shucks, honey, 66
+
+Sitka spruce, 28
+
+Silver birch, 42
+
+Silver-leaved maple, 69
+
+Silver maple, 69
+
+Slash pine, 25, 26
+
+Slippery elm, 51
+
+Small-leaved basswood, 39
+
+Small magnolia, 67
+
+Soft maple, 69
+
+Soft pine, 23, 24
+
+Soil and moisture, demands upon, 56
+
+Sorrel-tree, 80
+
+Sound pine, Puget, 29
+
+Sour gum, 62, 80
+
+Sourwood, 80
+
+Southern hard pine, 24
+
+Southern pine, 24
+
+Spanish oak, 75
+
+Spanish oak, swamp, 73
+
+Specialties, dry-kiln, 206
+
+Species, different kiln-drying according to, 170
+
+Species, temperature depends upon condition and, 171
+
+Species, weight of kiln-dried wood of different, 95
+
+Spindle tree, 82
+
+Splitting, prevention of checking and, 129
+
+Spring and summer-wood, 12
+
+Spruce, 27
+
+Spruce, bastard, 29
+
+Spruce, black, 27
+
+Spruce, Douglas, 29
+
+Spruce, hemlock, 21
+
+Spruce pine, 26
+
+Spruce, red, 28
+
+Spruce, Sitka, 28
+
+Spruce, tide-land, 28
+
+Spruce, white, 28
+
+Stain and mildew, elimination of, 136
+
+Stave, heading and shingle bolts, 109
+
+Staves and heads of barrels containing alcoholic liquids, 112
+
+Steam, drying by superheated, 150
+
+Steam gauge, the recording, 246
+
+Steaming of gum, preliminary, 182
+
+Steaming of gum, final, 182
+
+Stock and wooden truss hoops, dry cooperage, 112
+
+Straw pine, long, 24
+
+Straw pine, short, 25
+
+Striped maple, 70
+
+Structure, anatomical, 14
+
+Structure, minute, 34
+
+Structure of wood, 4
+
+Stump tree, 49
+
+Success in kiln-drying, conditions of, 169
+
+Sugar berry, 62
+
+Sugar maple, 68
+
+Sugar pine, 24
+
+Summerwood, spring and, 12
+
+Superheated steam, drying by, 150
+
+Swamp cottonwood, 78
+
+Swamp hickory, 64
+
+Swamp magnolia, 67
+
+Swamp maple, 69
+
+Swamp pine, 26
+
+Swamp poplar, 60
+
+Swamp post oak, 73
+
+Swamp Spanish oak, 73
+
+Swamp white oak, 72, 73
+
+Sweet bay, 67
+
+Sweet buckeye, 45
+
+Sweet birch, 41
+
+Sweet gum, 54, 80
+
+Sweet locust, 66
+
+Switchbud hickory, 64
+
+Sycamore, 80, 81
+
+
+Tacmahac, 79
+
+Tamarack, 22, 27, 29
+
+Temperature depends upon conditions and species, 171
+
+Test samples for scalometer, 248
+
+Theory and description of the forest service kiln, 161
+
+Theory of kiln-drying, 157
+
+Thermometer, the recording, 245
+
+Thermometer, the registering, 246
+
+Thorned acacia, three, 66
+
+Three-thorned acacia, 66
+
+Tide-land spruce, 28
+
+Timber, 1
+
+Timber beetles, ambrosia or, 99
+
+Timber with bark on, round, 106
+
+Timber worms, 103
+
+Tolerance of red gum, 56
+
+Toothed aspen, large-, 79
+
+Torch pine, 26
+
+Tower dry kiln, the, 202
+
+Treatments, preliminary, 151
+
+Tree, abele, 79
+
+Tree, bee, 39
+
+Tree, button ball, 80
+
+Tree, coffee, 49
+
+Tree, cucumber, 49, 67
+
+Tree, fir, 20
+
+Tree, lime, 39
+
+Tree, nettle, 62
+
+Tree of life, 17
+
+Tree, plane, 80
+
+Trees, broad-leaved, 31
+
+Trees, classes of, 5
+
+Trees, coniferous, 8
+
+Trees, list of important coniferous, 17
+
+Trees, list of most important broad-leaved, 37
+
+Tree, sorrel, 80
+
+Tree, spindle, 82
+
+Tree, stump, 49
+
+Trees, wood of broad-leaved, 31
+
+Trees, wood of the coniferous, 8
+
+Tree, tulip, 81
+
+Tree, umbrella, 67
+
+Troemroid Scalometer, the, 247
+
+Truss hoops, dry cooperage stock and, 112
+
+Tulip tree, 81
+
+Tulip wood, 67, 81
+
+Tupelo, 82
+
+Tupelo gum, 60
+
+Tupelo gum, range of, 61
+
+Tupelo gum, uses of, 61
+
+Types of dry kilns, different, 185
+
+Types of kiln doors, different, 231
+
+Types, kilns of different, 196
+
+
+Umbrella Tree, 67
+
+Underlying principles of kiln-drying, 166
+
+Unseasoned products in the rough, 109
+
+Unseasoned wood, difference between seasoned and, 121
+
+Unsolved problems in kiln-drying, 143
+
+Uses of the humidity diagram, 237
+
+Uses of tupelo gum, 61
+
+
+Vacuum, Drying under Pressure and, 146
+
+Valparaiso oak, 76
+
+Virgilia, 85
+
+
+Wahoo, 51, 82
+
+Walnut, 45, 82
+
+Walnut, black, 44, 82
+
+Walnut, circassian, 60
+
+Walnut, satin, 54
+
+Walnut, white, 45, 83
+
+Water beech, 44, 80
+
+Water by dry wood, absorption of, 124
+
+Water elm, 50
+
+Water in wood, 114
+
+Water in wood, distribution of, 114
+
+Water in wood, local distribution of, 114
+
+Water in wood, seasonal distribution of, 115
+
+Water lost in drying 100 lb. of green wood in the kiln, pounds of, 179
+
+Water, manner of evaporation of, 123
+
+Water maple, 69
+
+Water oak, 73
+
+Weeping willow, 84
+
+Weighing with scalometer, 248
+
+Weight, and figure in wood, grain, color, odor, 86
+
+Weight of kiln-dried wood of different species, 95
+
+Weight of wood, 91
+
+Western larch, 22
+
+Western pine, 25
+
+Western white oak, 71
+
+Western white pine, 25
+
+Western yellow pine, 25
+
+West, red cedar of the, 17
+
+Weymouth pine, 23
+
+What seasoning is, 119
+
+White ash, 37
+
+White basswood, 39
+
+White beech, 40
+
+White birch, 42, 43
+
+White cedar, 17, 18
+
+White cypress, 19
+
+White elm, 50
+
+White fir, 20, 21
+
+White heart hickory, 64
+
+White mahogany, 45
+
+White maple, 69
+
+White oak, 71, 72
+
+White oak, swamp, 72, 73
+
+White oak, western, 71
+
+White pine, 23, 24
+
+White pine, California, 25
+
+White pine, western, 25
+
+White poplar, 79, 81
+
+White spruce, 28
+
+White walnut, 45, 83
+
+White willow, 83
+
+Whitewood, 39, 81, 83
+
+Wild apple, 49
+
+Wild cherry, 47
+
+Wild red cherry, 47
+
+Willow, 83
+
+Willow, almond-leaf, 84
+
+Willow, bebb, 84
+
+Willow, black, 83
+
+Willow, blue, 83
+
+Willow, crack, 84
+
+Willow, glaucous, 84
+
+Willow, long-leaf, 84
+
+Willow, oak, 72
+
+Willow, perch, 84
+
+Willow, pussy, 84
+
+Willow, sand bar, 84
+
+Willow, shining, 84
+
+Willow, weeping, 84
+
+Willow, white, 83
+
+Willow, yellow, 83
+
+Winged elm, 51
+
+Wintergreen birch, 41
+
+Wood, absorption of water by dry, 124
+
+Wood, beaver, 67
+
+Wood, canary, 81
+
+Wood, characteristics and properties of, 1
+
+Wood, color and odor of, 89
+
+Wood, different grains of, 86
+
+Wood, difference between seasoned and unseasoned, 121
+
+Wood, difficulties of drying, 138
+
+Wood, distribution of water in, 114
+
+Wood, effects of moisture on, 117
+
+Wood, enemies of, 98
+
+Wood, expansion of, 135
+
+Wood, figure in, 96
+
+Wood, grain, color, odor, weight, and figure in, 86
+
+Wood, how seasoned, 145
+
+Wood in the kiln, pounds of water lost in drying 100 lb. of green, 179
+
+Wood, iron, 65
+
+Wood, kiln-drying of, 156
+
+Wood, lever, 65
+
+Wood, local distribution of water in, 114
+
+Wood, moose, 70
+
+Wood, of broad-leaves trees, 31
+
+Wood of different species, weight of kiln-dried, 95
+
+Wood of coniferous trees, 8
+
+Wood, physical conditions governing the drying of, 156
+
+Wood, properties of, 4
+
+Wood, seasonal distribution of water in, 115
+
+Wood, shrinkage of, 130
+
+Woods, list of important coniferous, 17
+
+Wood, spring and summer, 12
+
+Wood, structure of, 4
+
+Wood that effect drying, properties of, 141
+
+Wood, the fibre saturation point in, 118
+
+Wood, tulip, 67, 81
+
+Wood, water in, 114
+
+Wood, weight of, 89
+
+Wood, white, 81, 83
+
+Wood, yellow, 85
+
+Wooden truss hoops, dry cooperage, stock and, 112
+
+Worms, timber, 103
+
+
+Yearly Ring, the Annual of, 10
+
+Yellow birch, 42
+
+Yellow cedar, 18
+
+Yellow deal, 23
+
+Yellow fir, 29
+
+Yellow locust, 66
+
+Yellow oak, 73, 74
+
+Yellow pine, 24, 25, 26
+
+Yellow pine, western, 25
+
+Yellow poplar, 81
+
+Yellow willow, 83
+
+Yellow wood, 85
+
+Yew, 29, 30
+
+
+
+
+                        D. VAN NOSTRAND COMPANY
+                             25 PARK PLACE
+                               NEW YORK
+
+
+                          SHORT-TITLE CATALOG
+                                  OF
+                     Publications and Importations
+                                  OF
+                      SCIENTIFIC AND ENGINEERING
+                                 BOOKS
+
+                            [Illustration]
+
+                          This list includes
+    the technical publications of the following English publishers:
+
+            SCOTT, GREENWOOD & CO. JAMES MUNRO & CO., Ltd.
+          CONSTABLE & COMPANY, Ltd. TECHNICAL PUBLISHING CO.
+                 ELECTRICIAN PRINTING & PUBLISHING CO.
+
+         for whom D. Van Nostrand Company are American agents.
+
+
+
+
+                                                      JULY, 1917
+
+                          SHORT-TITLE CATALOG
+                                OF THE
+                     Publications and Importations
+                                  OF
+                        D. VAN NOSTRAND COMPANY
+                         25 PARK PLACE, N. Y.
+
+             _Prices marked with an asterisk (*) are NET._
+
+          _All bindings are in cloth unless otherwise noted._
+
+
+Abbott, A. V. The Electrical Transmission of Energy          8vo, *$5 00
+
+---- A Treatise on Fuel. (Science Series No. 9)             16mo,   0 50
+
+---- Testing Machines. (Science Series No. 74.)             16mo,   0 50
+
+Adam, P. Practical Bookbinding. Trans. by T. E. Maw         12mo,  *2 50
+
+Adams, H. Theory and Practice in Designing                   8vo,  *2 50
+
+Adams, H. C. Sewage of Sea Coast Towns                       8vo,  *2 00
+
+Adams, J. W. Sewers and Drains for Populous Districts        8vo,   2 50
+
+Adler, A. A. Theory of Engineering Drawing                   8vo,  *2 00
+
+---- Principles of Parallel Projecting-line Drawing          8vo,  *1 00
+
+Aikman, C. M. Manures and the Principles of Manuring         8vo,   2 50
+
+Aitken, W. Manual of the Telephone                           8vo,  *8 00
+
+d'Albe, E. E. F., Contemporary Chemistry                    12mo,  *1 25
+
+Alexander, J. H. Elementary Electrical Engineering          12mo,   2 00
+
+Allan, W. Strength of Beams Under Transverse Loads.
+  (Science Series No. 19.)                                  16mo,   0 50
+
+---- Theory of Arches. (Science Series No. 11)              16mo,
+
+Allen, H. Modern Power Gas Producer Practice and
+  Applications.                                             12mo,  *2 50
+
+Anderson, J. W. Prospector's Handbook                       12mo,   1 50
+
+Andés, L. Vegetable Fats and Oils                            8vo,  *4 00
+
+---- Animal Fats and Oils. Trans. by C. Salter               8vo,  *4 00
+
+---- Drying Oils, Boiled Oil, and Solid and Liquid Driers    8vo,  *5 00
+
+---- Iron Corrosion, Anti-fouling and Anti-corrosive
+  Paints. Trans. by C. Salter                                8vo,  *4 00
+
+---- Oil Colors, and Printers' Ink. Trans. by A. Morris
+  and H. Robson                                              8vo,  *2 50
+
+---- Treatment of Paper for Special Purposes. Trans.
+  by C. Salter                                              12mo,  *2 50
+
+Andrews, E. S. Reinforced Concrete Construction             12mo,  *1 50
+
+---- Theory and Design of Structures                         8vo,  *3 50
+
+---- Further Problems in the Theory and Design
+  of Structures                                              8vo,  *2 50
+
+---- The Strength of Materials                               8vo,  *4 00
+
+Andrews, E. S., and Heywood, H. B. The Calculus
+  for Engineers.                                            12mo,  *1 50
+
+Annual Reports on the Progress of Chemistry. Twelve
+  Volumes now ready. Vol. I., 1904, Vol. XII., 1914    8vo, each,  *2 00
+
+Argand, M. Imaginary Quantities. Translated from the
+  French by A. S. Hardy. (Science Series No. 52.)           16mo,   0 50
+
+Armstrong, R., and Idell, F. E. Chimneys for Furnaces
+  and Steam Boilers. (Science Series No. 1.)                16mo,   0 50
+
+Arnold, E. Armature Windings of Direct-Current Dynamos.
+  Trans. by F. B. DeGress                                    8vo,  *2 00
+
+Asch, W., and Asch, D. The Silicates in Chemistry
+  and Commerce                                               8vo,  *6 00
+
+Ashe, S. W., and Kelley, J. D. Electric Railways.
+  Theoretically and Practically Treated. Vol. I.
+  Rolling Stock                                             12mo,  *2 50
+
+Ashe, S. W. Electric Railways. Vol. II. Engineering
+  Preliminaries and Direct Current Sub-Stations             12mo,  *2 50
+
+---- Electricity: Experimentally and Practically Applied    12mo,  *2 00
+
+Ashley, R. H. Chemical Calculations                         12mo,  *2 00
+
+Atkins, W. Common Battery Telephony Simplified              12mo,  *1 25
+
+Atkinson, A. A. Electrical and Magnetic Calculations         8vo,  *1 50
+
+Atkinson, J. J. Friction of Air in Mines. (Science
+  Series No. 14.)                                           16mo,   0 50
+
+Atkinson, J. J., and Williams, Jr., E. H. Gases Met
+  with in Coal Mines. (Science Series No. 13.)              16mo,   0 50
+
+Atkinson, P. The Elements of Electric Lighting              12mo,   1 00
+
+---- The Elements of Dynamic Electricity and Magnetism      12mo,   2 00
+
+---- Power Transmitted by Electricity                       12mo,   2 00
+
+Auchincloss, W. S. Link and Valve Motions Simplified         8vo,  *1 50
+
+Austin, E. Single Phase Electric Railways                    4to,  *5 00
+
+Austin and Cohn. Pocketbook of Radiotelegraphy      (_In Press._)
+
+Ayrton, H. The Electric Arc                                  8vo,  *5 00
+
+
+Bacon, F. W. Treatise on the Richards Steam-Engine
+  Indicator                                                 12mo,   1 00
+
+Bailey, R. D. The Brewers' Analyst                           8vo,  *5 00
+
+Baker, A. L. Quaternions                                     8vo,  *1 25
+
+---- Thick-Lens Optics                                      12mo,  *1 50
+
+Baker, Benj. Pressure of Earthwork. (Science
+  Series No. 56.)                                           16mo,
+
+Baker, G. S. Ship Form, Resistance and Screw Propulsion      8vo,  *4 50
+
+Baker, I. O. Levelling. (Science Series No. 91.)            16mo,   0 50
+
+Baker, M. N. Potable Water. (Science Series No. 61.)        16mo,   0 50
+
+---- Sewerage and Sewage Purification. (Science
+  Series No. 18.)                                           16mo,   0 50
+
+Baker, T. T. Telegraphic Transmission of Photographs        12mo,  *1 25
+
+Bale, G. R. Modern Iron Foundry Practice. Two Volumes.      12mo.
+    Vol. I. Foundry Equipment, Materials Used                      *2 50
+    Vol. II. Machine Moulding and Moulding Machines                *1 50
+
+Ball, J. W. Concrete Structures in Railways                  8vo,  *2 50
+
+Ball, R. S. Popular Guide to the Heavens                     8vo,  *5 00
+
+---- Natural Sources of Power. (Westminster Series.)         8vo,  *2 00
+
+Ball, W. V. Law Affecting Engineers                          8vo,  *3 50
+
+Bankson, Lloyd. Slide Valve Diagrams. (Science
+  Series No. 108.).                                         16mo,   0 50
+
+Barham, G. B. Development of the Incandescent Electric
+  Lamp                                                       8vo,  *2 00
+
+Barker, A. F. Textiles and Their Manufacture.
+  (Westminster Series.)                                      8vo,   2 00
+
+Barker, A. F., and Midgley, E. Analysis of Textile Fabrics   8vo,   3 00
+
+Barker, A. H. Graphic Methods of Engine Design              12mo,  *1 50
+
+---- Heating and Ventilation                                 4to,  *8 00
+
+Barnard, J. H. The Naval Militiaman's Guide        16mo, leather,   1 00
+
+Barnard, Major J. G. Rotary Motion. (Science
+  Series No. 90.)                                           16mo,   0 50
+
+Barnes, J. B. Elements of Military Sketching                16mo,  *0 60
+
+Barrus, G. H. Engine Tests                                   8vo,  *4 00
+
+Barwise, S. The Purification of Sewage                      12mo,   3 50
+
+Baterden, J. R. Timber. (Westminster Series.)                8vo,  *2 00
+
+Bates, E. L., and Charlesworth, F. Practical Mathematics
+  and Geometry                                              12mo,
+    Part I. Preliminary and Elementary Course                      *1 50
+    Part II. Advanced Course                                       *1 50
+
+---- Practical Mathematics                                  12mo,  *1 50
+
+---- Practical Geometry and Graphics                        12mo,  *2 00
+
+Batey, J. The Science of Works Management                   12mo,  *1 50
+
+---- Steam Boilers and Combustion                           12mo,  *1 50
+
+Bayonet Training Manual                                     16mo,   0 30
+
+Beadle, C. Chapters on Papermaking. Five Volumes      12mo, each,  *2 00
+
+Beaumont, R. Color in Woven Design                           8vo,  *6 00
+
+---- Finishing of Textile Fabrics                            8vo,  *4 00
+
+---- Standard Cloths                                         8vo,  *5 00
+
+Beaumont, W. W. The Steam-Engine Indicator                   8vo,   2 50
+
+Bechhold, H. Colloids in Biology and Medicine. Trans.
+  by J. G. Bullowa                                         (_In Press._)
+
+Beckwith, A. Pottery                                  8vo, paper,   0 60
+
+Bedell, F., and Pierce, C. A. Direct and Alternating
+  Current Manual                                             8vo,   4 00
+
+Beech, F. Dyeing of Cotton Fabrics                           8vo,   4 00
+
+---- Dyeing of Woolen Fabrics                                8vo,  *3 50
+
+Begtrup, J. The Slide Valve                                  8vo,  *2 00
+
+Beggs, G. E. Stresses in Railway Girders and Bridges       (_In Press._)
+
+Bender, C. E. Continuous Bridges. (Science Series No. 26.)  16mo,   0 50
+
+---- Proportions of Pins used in Bridges. (Science
+  Series No. 4.)                                            16mo,   0 50
+
+Bengough, G. D. Brass. (Metallurgy Series.)                (_In Press._)
+
+Bennett, H. G. The Manufacture of Leather                    8vo,  *5 00
+
+Bernthsen, A. A Text book of Organic Chemistry. Trans.
+  by G. M'Gowan                                             12mo,  *3 00
+
+Bersch. J. Manufacture of Mineral and Lake Pigments.
+  Trans. by A. C. Wright                                     8vo,  *5 00
+
+Bertin, L. E. Marine Boilers. Trans. by L. S. Robertson      8vo,   5 00
+
+Beveridge, J. Papermaker's Pocket Book                      12mo,  *4 00
+
+Binnie, Sir A. Rainfall Reservoirs and Water Supply          8vo,   3 00
+
+Binns, C. F. Manual of Practical Potting                     8vo,  *7 50
+
+---- The Potter's Craft                                     12mo,  *2 00
+
+Birchmore, W. H. Interpretation of Gas Analysis             12mo,  *1 25
+
+Blaine, R. G. The Calculus and Its Applications             12mo,  *1 50
+
+Blake, W. H. Brewers' Vade Mecum                             8vo,  *4 00
+
+Blasdale, W. C. Quantitative Chemical Analysis.
+  (Van Nostrand's Textbooks.)                               12mo,  *2 50
+
+Bligh, W. G. The Practical Design of Irrigation Works        8vo,  *6 00
+
+Bloch, L. Science of Illumination. Trans. by W. C. Clinton   8vo,  *2 50
+
+Blok, A. Illumination and Artificial Lighting               12mo,   1 25
+
+Blücher, H. Modern Industrial Chemistry. Trans. by
+  J. P. Millington.                                          8vo,  *7 50
+
+Blyth, A. W. Foods: Their Composition and Analysis           8vo,   7 50
+
+---- Poisons: Their Effects and Detection                    8vo,   7 50
+
+Böckmann, F. Celluloid                                      12mo,  *2 50
+
+Bodmer, G. R. Hydraulic Motors and Turbines                 12mo,   5 00
+
+Boileau, J. T. Traverse Tables                               8vo,   5 00
+
+Bonney, G. E. The Electro-platers' Handbook                 12mo,   1 50
+
+Booth, N. Guide to the Ring-spinning Frame                  12mo,  *1 25
+
+Booth, W. H. Water Softening and Treatment                   8vo,  *2 50
+
+---- Superheaters and Superheating and Their Control         8vo,  *1 50
+
+Bottcher, A. Cranes: Their Construction, Mechanical
+  Equipment and Working. Trans. by A. Tolhausen              4to, *10 00
+
+Bottler, M. Modern Bleaching Agents. Trans. by C. Salter    12mo,  *2 50
+
+Bottone, S. R. Magnetos for Automobilists                   12mo,  *1 00
+
+Boulton, S. B. Preservation of Timber. (Science
+  Series No. 82.).                                          16mo,   0 50
+
+Bourcart, E. Insecticides, Fungicides and Weedkillers        8vo,  *4 50
+
+Bourgougnon, A. Physical Problems. (Science Series
+  No. 113.)                                                 16mo,   0 50
+
+Bourry, E. Treatise on Ceramic Industries. Trans.
+  by A. B. Searle.                                           8vo,  *5 00
+
+Bowie, A. J., Jr. A Practical Treatise on Hydraulic Mining   8vo,   5 00
+
+Bowles, O. Tables of Common Rocks. (Science Series
+  No. 125.).                                                16mo,   0 50
+
+Bowser, E. A. Elementary Treatise on Analytic Geometry      12mo,   1 75
+
+---- Elementary Treatise on the Differential and
+   Integral Calculus.                                       12mo,   2 25
+
+---- Elementary Treatise on Analytic Mechanics              12mo,   3 00
+
+---- Elementary Treatise on Hydro-mechanics                 12mo,   2 50
+
+---- A Treatise on Roofs and Bridges                        12mo,  *2 25
+
+Boycott, G. W. M. Compressed Air Work and Diving             8vo,  *4 00
+
+Bragg, E. M. Marine Engine Design                           12mo,  *2 00
+
+---- Design of Marine Engines and Auxiliaries                8vo,  *3 00
+
+Brainard, F. R. The Sextant. (Science Series No. 101.)      16mo,
+
+Brassey's Naval Annual for 1915. War Edition                 8vo,   4 00
+
+Briggs, R., and Wolff, A. R. Steam-Heating. (Science
+  Series No. 67.)                                           16mo,   0 50
+
+Bright, C. The Life Story of Sir Charles Tilson Bright       8vo,  *4 50
+
+Brislee, T. J. Introduction to the Study of Fuel.
+  (Outlines of Industrial Chemistry.)                        8vo,  *3 00
+
+Broadfoot, S. K. Motors, Secondary Batteries.
+  (Installation Manuals Series.)                            12mo,  *0 75
+
+Broughton, H. H. Electric Cranes and Hoists                        *9 00
+
+Brown, G. Healthy Foundations. (Science Series No. 80.)     16mo,   0 50
+
+Brown, H. Irrigation                                         8vo,  *5 00
+
+Brown, H. Rubber                                             8vo,  *2 00
+
+---- W. A. Portland Cement Industry                          8vo,   3 00
+
+Brown, Wm. N. Dipping, Burnishing, Lacquering and Bronzing
+  Brass Ware                                                12mo,  *1 25
+
+---- Handbook on Japanning                                  12mo,  *1 50
+
+Brown, Wm. N. The Art of Enamelling on Metal                12mo,  *1 00
+
+---- House Decorating and Painting                          12mo,  *1 50
+
+---- History of Decorative Art                              12mo,  *1 25
+
+---- Workshop Wrinkles                                       8vo,  *1 00
+
+Browne, C. L. Fitting and Erecting of Engines                8vo,  *1 50
+
+Browne, R. E. Water Meters. (Science Series No. 81.)        16mo,   0 50
+
+Bruce, E. M. Pure Food Tests                                12mo,  *1 25
+
+Brunner, R. Manufacture of Lubricants, Shoe Polishes
+   and Leather Dressings. Trans. by C. Salt                  8vo,  *3 00
+
+Buel, R. H. Safety Valves. (Science Series No. 21.)         16mo,   0 50
+
+Burley, G. W. Lathes, Their Construction and Operation      12mo,   1 25
+
+Burnside, W. Bridge Foundations                             12mo,  *1 50
+
+Burstall, F. W. Energy Diagram for Gas. With Text            8vo,   1 50
+
+---- Diagram. Sold separately                                      *1 00
+
+Burt, W. A. Key to the Solar Compass               16mo, leather,   2 50
+
+Buskett, E. W. Fire Assaying                                12mo,  *1 25
+
+Butler, H. J. Motor Bodies and Chassis                       8vo,  *2 50
+
+Byers, H. G., and Knight, H. G. Notes on Qualitative
+  Analysis                                                   8vo,  *1 50
+
+
+Cain, W. Brief Course in the Calculus                       12mo,  *1 75
+
+---- Elastic Arches. (Science Series No. 48.)               16mo,   0 50
+
+---- Maximum Stresses. (Science Series No. 38.)             16mo,   0 50
+
+---- Practical Designing Retaining of Walls. (Science
+  Series No. 3.)                                            16mo,   0 50
+
+---- Theory of Steel-concrete Arches and of Vaulted
+  Structures. (Science Series No. 42.)                      16mo,   0 50
+
+---- Theory of Voussoir Arches. (Science Series No. 12.)    16mo,   0 50
+
+---- Symbolic Algebra. (Science Series No. 73.)             16mo,   0 50
+
+Carpenter, F. D. Geographical Surveying. (Science
+  Series No. 37.)                                           16mo,
+
+Carpenter, R. C., and Diederichs, H. Internal Combustion
+  Engines                                                    8vo,  *5 00
+
+Carter, H. A. Ramie (Rhea), China Grass                     12mo,  *2 00
+
+Carter, H. R. Modern Flax, Hemp, and Jute Spinning           8vo,  *3 00
+
+---- Bleaching, Dyeing and Finishing of Fabrics              8vo,  *1 00
+
+Cary, E. R. Solution of Railroad Problems with the
+  Slide Rule                                                16mo,  *1 00
+
+Casler, M. D. Simplified Reinforced Concrete Mathematics    12mo,  *1 00
+
+Cathcart, W. L. Machine Design. Part I. Fastenings           8vo,  *3 00
+
+Cathcart, W. L., and Chaffee, J. I. Elements of
+  Graphic Statics                                            8vo,  *3 00
+
+---- Short Course in Graphics                               12mo,   1 50
+
+Caven, R. M., and Lander, G. D. Systematic Inorganic
+  Chemistry                                                 12mo,  *2 00
+
+Chalkley, A. P. Diesel Engines                               8vo,  *4 00
+
+Chambers' Mathematical Tables                                8vo,   1 75
+
+Chambers, G. F. Astronomy                                   16mo,  *1 50
+
+Chappel, E. Five Figure Mathematical Tables                  8vo,  *2 00
+
+Charnock, Mechanical Technology                              8vo,  *3 00
+
+Charpentier, P. Timber                                       8vo,  *6 00
+
+Chatley, H. Principles and Designs of Aeroplanes.
+  (Science Series No. 126)                                  16mo,   0 50
+
+---- How to Use Water Power                                 12mo,  *1 00
+
+---- Gyrostatic Balancing                                    8vo,  *1 00
+
+Child, C. D. Electric Arc                                    8vo,  *2 00
+
+Christian, M. Disinfection and Disinfectants. Trans.
+  by Chas. Salter                                           12mo,   2 00
+
+Christie, W. W. Boiler-waters, Scale, Corrosion, Foaming     8vo,  *3 00
+
+---- Chimney Design and Theory                               8vo,  *3 00
+
+---- Furnace Draft. (Science Series No. 123.)               16mo,   0 50
+
+---- Water: Its Purification and Use in the Industries       8vo,  *2 00
+
+Church's Laboratory Guide. Rewritten by Edward Kinch         8vo,  *1 50
+
+Clapham, J. H. Woolen and Worsted Industries                 8vo,   2 00
+
+Clapperton, G. Practical Papermaking                         8vo,   2 50
+
+Clark, A. G. Motor Car Engineering.
+    Vol. I. Construction                                           *3 00
+    Vol. II. Design                                          8vo,  *3 00
+
+Clark, C. H. Marine Gas Engines                             12mo,  *1 50
+
+Clark, J. M. New System of Laying Out Railway Turnouts      12mo,   1 00
+
+Clarke, J. W., and Scott, W. Plumbing Practice.
+    Vol. I. Lead Working and Plumbers' Materials             8vo,  *4 00
+    Vol. II. Sanitary Plumbing and Fittings                (_In Press._)
+    Vol. III. Practical Lead Working on Roofs              (_In Press._)
+
+Clarkson, R. B. Elementary Electrical Engineering          (_In Press._)
+
+Clausen-Thue, W. A B C Universal Commercial Telegraphic
+  Code. Sixth Edition                                      (_In Press._)
+
+Clerk, D., and Idell, F. E. Theory of the Gas Engine.
+  (Science Series No. 62.)                                  16mo,   0 50
+
+Clevenger, S. R. Treatise on the Method of
+  Government Surveying.                            16mo, morocco,   2 50
+
+Clouth, F. Rubber, Gutta-Percha, and Balata                  8vo,  *5 00
+
+Cochran, J. Concrete and Reinforced Concrete Specifications  8vo,  *2 50
+
+---- Inspection of Concrete Construction                     8vo,  *4 00
+
+---- Treatise on Cement Specifications                       8vo,  *1 00
+
+Cocking, W. C. Calculations for Steel-Frame Structures      12mo,  *2 25
+
+Coffin, J. H. C. Navigation and Nautical Astronomy          12mo,  *3 50
+
+Colburn, Z., and Thurston, R. H. Steam Boiler
+  Explosions. (Science Series No. 2.)                       16mo,   0 50
+
+Cole, R. S. Treatise on Photographic Optics                 12mo,   1 50
+
+Coles-Finch, W. Water, Its Origin and Use                    8vo,  *5 00
+
+Collins, J. E. Useful Alloys and Memoranda for
+  Goldsmiths, Jewelers.                                     16mo,   0 50
+
+Collis, A. G. High and Low Tension Switch-Gear Design        8vo,  *3 50
+
+---- Switchgear. (Installation Manuals Series.)             12mo,  *0 50
+
+Comstock, D. F., and Troland, L. T. The Nature
+  of Electricity and Matter                                  8vo,  *2 00
+
+Coombs, H. A. Gear Teeth. (Science Series No. 120.)         16mo,   0 50
+
+Cooper, W. R. Primary Batteries                              8vo,  *4 00
+
+Copperthwaite, W. C. Tunnel Shields                          4to,  *9 00
+
+Corfield, W. H. Dwelling Houses. (Science Series No. 50.)   16mo,   0 50
+
+---- Water and Water-Supply. (Science Series No. 17.)       16mo,   0 50
+
+Cornwall, H. B. Manual of Blow-pipe Analysis                 8vo,  *2 50
+
+Cowee, G. A. Practical Safety Methods and Devices            8vo,  *3 00
+
+Cowell, W. B. Pure Air, Ozone, and Water                    12mo,  *2 00
+
+Craig, J. W., and Woodward, W. P. Questions and
+  Answers About Electrical Apparatus               12mo, leather,   1 50
+
+Craig, T. Motion of a Solid in a Fuel. (Science
+  Series No. 49.)                                           16mo,   0 50
+
+---- Wave and Vortex Motion. (Science Series No. 43.)       16mo,   0 50
+
+Cramp, W. Continuous Current Machine Design                  8vo,  *2 50
+
+Crehore, A. C. Mystery of Matter and Energy                  8vo,   1 00
+
+Creedy, F. Single Phase Commutator Motors                    8vo,  *2 00
+
+Crocker, F. B. Electric Lighting. Two Volumes.               8vo,
+    Vol. I. The Generating Plant                                    3 00
+    Vol. II. Distributing Systems and Lamps
+
+Crocker, F. B., and Arendt, M. Electric Motors               8vo,  *2 50
+
+Crocker, F. B., and Wheeler, S. S. The Management
+  of Electrical Machinery                                   12mo,  *1 00
+
+Cross, C. F., Bevan, E. J., and Sindall, R. W. Wood
+  Pulp and Its Applications. (Westminster Series.)           8vo,  *2 00
+
+Crosskey, L. R. Elementary Perspective                       8vo,   1 25
+
+Crosskey, L. R., and Thaw, J. Advanced Perspective           8vo,   1 50
+
+Culley, J. L. Theory of Arches. (Science Series No. 87.)    16mo,   0 50
+
+Cushing, H. C., Jr., and Harrison, N. Central Station
+  Management                                                       *2 00
+
+
+Dadourian, H. M. Analytical Mechanics                       12mo,  *3 00
+
+Dana, R. T. Handbook of Construction plant         12mo, leather,  *5 00
+
+Danby, A. Natural Rock Asphalts and Bitumens                 8vo,  *2 50
+
+Davenport, C. The Book. (Westminster Series.)                8vo,  *2 00
+
+Davey, N. The Gas Turbine                                    8vo,  *4 00
+
+Davies, F. H. Electric Power and Traction                    8vo,  *2 00
+
+---- Foundations and Machinery Fixing. (Installation
+  Manual Series.)                                           16mo,  *1 00
+
+Deerr, N. Sugar Cane                                         8vo,   8 00
+
+Deite, C. Manual of Soapmaking. Trans. by S. T. King         4to,  *5 00
+
+De la Coux, H. The Industrial Uses of Water. Trans.
+  by A. Morris.                                              8vo,  *4 50
+
+Del Mar, W. A. Electric Power Conductors                     8vo,  *2 00
+
+Denny, G. A. Deep-level Mines of the Rand                    4to, *10 00
+
+---- Diamond Drilling for Gold                                     *5 00
+
+De Roos, J. D. C. Linkages. (Science Series No. 47.)        16mo,   0 50
+
+Derr, W. L. Block Signal Operation                   Oblong 12mo,  *1 50
+
+---- Maintenance-of-Way Engineering                  (_In Preparation._)
+
+Desaint, A. Three Hundred Shades and How to Mix Them         8vo,  *8 00
+
+De Varona, A. Sewer Gases. (Science Series No. 55.)         16mo,   0 50
+
+Devey, R. G. Mill and Factory Wiring. (Installation
+  Manuals Series.)                                          12mo,  *1 00
+
+Dibdin, W. J. Purification of Sewage and Water               8vo,   6 50
+
+Dichmann, Carl. Basic Open-Hearth Steel Process             12mo,  *3 50
+
+Dieterich, K. Analysis of Resins, Balsams, and Gum Resins    8vo,  *3 00
+
+Dilworth, E. C. Steel Railway Bridges                        4to,  *4 00
+
+Dinger, Lieut. H. C. Care and Operation of Naval
+  Machinery                                                 12mo,  *2 00
+
+Dixon, D. B. Machinist's and Steam Engineer's
+  Practical Calculator.                            16mo, morocco,   1 25
+
+Dodge, G. F. Diagrams for Designing Reinforced
+  Concrete Structures,                                     folio,  *4 00
+
+Dommett, W. E. Motor Car Mechanism                          12mo,  *1 50
+
+Dorr, B. F. The Surveyor's Guide and Pocket
+  Table-book.                                      16mo, morocco,   2 00
+
+Draper, C. H. Elementary Text-book of Light,
+  Heat and Sound                                            12mo,   1 00
+
+---- Heat and the Principles of Thermo-dynamics             12mo,  *2 00
+
+Dron, R. W. Mining Formulas                                 12mo,   1 00
+
+Dubbel, H. High Power Gas Engines                            8vo,  *5 00
+
+Dumesny, P., and Noyer, J. Wood Products, Distillates,
+  and Extracts.                                              8vo,  *4 50
+
+Duncan, W. G., and Penman, D. The Electrical Equipment
+  of Collieries.                                             8vo,  *4 00
+
+Dunkley, W. G. Design of Machine Elements                    8vo,   1 50
+
+Dunstan, A. E., and Thole, F. B. T. Textbook of
+  Practical Chemistry.                                      12mo,  *1 40
+
+Durham, H. W. Saws                                           8vo,   2 50
+
+Duthie, A. L. Decorative Glass Processes.
+  (Westminster Series.).                                     8vo,  *2 00
+
+Dwight, H. B. Transmission Line Formulas                     8vo,  *2 00
+
+Dyson, S. S. Practical Testing of Raw Materials              8vo,  *5 00
+
+Dyson, S. S., and Clarkson, S. S. Chemical Works             8vo,  *7 50
+
+
+Eccles, W. H. Wireless Telegraphy and Telephony             12mo,  *4 50
+
+Eck, J. Light, Radiation and Illumination. Trans.
+  by Paul Hogner,                                            8vo,  *2 50
+
+Eddy, H. T. Maximum Stresses under Concentrated Loads        8vo,   1 50
+
+Eddy, L. C. Laboratory Manual of Alternating Currents       12mo,   0 50
+
+Edelman, P. Inventions and Patents                          12mo,  *1 50
+
+Edgcumbe, K. Industrial Electrical Measuring
+  Instruments                                         8vo, (_In Press._)
+
+Edler, R. Switches and Switchgear. Trans.
+  by Ph. Laubach                                             8vo,  *4 00
+
+Eissler, M. The Metallurgy of Gold                           8vo,   7 50
+
+---- The Metallurgy of Silver                                8vo,   4 00
+
+---- The Metallurgy of Argentiferous Lead                    8vo,   5 00
+
+---- A Handbook on Modern Explosives                         8vo,   5 00
+
+Ekin, T. C. Water Pipe and Sewage Discharge Diagrams       folio,  *3 00
+
+Electric Light Carbons, Manufacture of                       8vo,   1 00
+
+Eliot, C. W., and Storer, F. H. Compendious Manual
+  of Qualitative Chemical Analysis                          12mo,  *1 25
+
+Ellis, C. Hydrogenation of Oils                       8vo, (_In Press._)
+
+Ellis, G. Modern Technical Drawing                           8vo,  *2 00
+
+Ennis, Wm. D. Linseed Oil and Other Seed Oils                8vo,  *4 00
+
+---- Applied Thermodynamics                                  8vo,  *4 50
+
+---- Flying Machines To-day                                 12mo,  *1 50
+
+---- Vapors for Heat Engines                                12mo,  *1 00
+
+Ermen, W. F. A. Materials Used in Sizing                     8vo,  *2 00
+
+Erwin, M. The Universe and the Atom                         12mo,  *2 00
+
+Evans, C. A. Macadamized Roads                             (_In Press._)
+
+Ewing, A. J. Magnetic Induction in Iron                      8vo,  *4 00
+
+
+Fairie, J. Notes on Lead Ores                               12mo,  *0 50
+
+---- Notes on Pottery Clays                                 12mo,  *1 50
+
+Fairley, W., and Andre, Geo. J. Ventilation of Coal
+  Mines. (Science Series No. 58.)                           16mo,   0 50
+
+Fairweather, W. C. Foreign and Colonial Patent Laws          8vo,  *3 00
+
+Falk, M. S. Cement Mortars and Concretes                     8vo,  *2 50
+
+Fanning, J. T. Hydraulic and Water-supply Engineering        8vo,  *5 00
+
+Fay, I. W. The Coal-tar Colors                               8vo,  *4 00
+
+Fernbach, R. L. Glue and Gelatine                            8vo,  *3 00
+
+Firth, J. B. Practical Physical Chemistry                   12mo,  *1 00
+
+Fischer, E. The Preparation of Organic Compounds.
+  Trans. by R. V. Stanford                                  12mo,  *1 25
+
+Fish, J. C. L. Lettering of Working Drawings          Oblong 8vo,   1 00
+
+---- Mathematics of the Paper Location of a Railroad
+  paper                                                     12mo,  *0 25
+
+Fisher, H. K. C., and Darby, W. C. Submarine Cable
+  Testing                                                    8vo,  *3 50
+
+Fleischmann, W. The Book of the Dairy. Trans. by
+  C. M. Aikman                                               8vo,   4 00
+
+Fleming, J. A. The Alternate-current Transformer. Two
+  Volumes.                                                   8vo.
+    Vol. I. The Induction of Electric Currents                     *5 00
+    Vol. II. The Utilization of Induced Currents                   *5 00
+
+---- Propagation of Electric Currents                        8vo,  *3 00
+
+---- A Handbook for the Electrical Laboratory and
+  Testing Room. Two Volumes                            8vo, each,  *5 00
+
+Fleury, P. Preparation and Uses of White Zinc Paints         8vo,  *2 50
+
+Flynn, P. J. Flow of Water. (Science Series No. 84.)        12mo,   0 50
+
+---- Hydraulic Tables. (Science Series No. 66.)             16mo,   0 50
+
+Forgie, J. Shield Tunneling                           8vo. (_In Press._)
+
+Foster, H. A. Electrical Engineers' Pocket-book.
+  (_Seventh Edition._)                             12mo, leather,   5 00
+
+---- Engineering Valuation of Public Utilities
+  and Factories                                              8vo,  *3 00
+
+---- Handbook of Electrical Cost Data                  8vo (_In Press._)
+
+Fowle, F. F. Overhead Transmission Line Crossings           12mo,  *1 50
+
+---- The Solution of Alternating Current Problems      8vo (_In Press._)
+
+Fox, W. G. Transition Curves. (Science Series No. 110.)     16mo,   0 50
+
+Fox, W., and Thomas, C. W. Practical Course in
+  Mechanical Drawing                                        12mo,   1 25
+
+Foye, J. C. Chemical Problems.
+  (Science Series No. 69.)                                  16mo,   0 50
+
+---- Handbook of Mineralogy. (Science Series No. 86.)       16mo,   0 50
+
+Francis, J. B. Lowell Hydraulic Experiments                  4to,  15 00
+
+Franzen, H. Exercises in Gas Analysis                       12mo,  *1 00
+
+Freudemacher, P. W. Electrical Mining Installations.
+  (Installation Manuals Series.)                            12mo,  *1 00
+
+Frith, J. Alternating Current Design                         8vo,  *2 00
+
+Fritsch, J. Manufacture of Chemical Manures. Trans.
+  by D. Grant.                                               8vo,  *4 00
+
+Frye, A. I. Civil Engineers' Pocket-book           12mo, leather,  *5 00
+
+Fuller, G. W. Investigations into the Purification of
+  the Ohio River                                             4to, *10 00
+
+Furnell, J. Paints, Colors, Oils, and Varnishes              8vo,  *1 00
+
+
+Gairdner, J. W. I. Earthwork                           8vo (_In Press._)
+
+Gant, L. W. Elements of Electric Traction                    8vo,  *2 50
+
+Garcia, A. J. R. V. Spanish-English Railway Terms            8vo,  *4 50
+
+Gardner, H. A. Paint Researches, and Their Practical
+  Applications                                               8vo,  *5 00
+
+Garforth, W. E. Rules for Recovering Coal Mines
+  after Explosions and Fires                       12mo, leather,   1 50
+
+Garrard, C. C. Electric Switch and Controlling Gear          8vo,  *6 00
+
+Gaudard, J. Foundations. (Science Series No. 34.)           16mo,   0 50
+
+Gear, H. B., and Williams, P. F. Electric Central
+  Station Distribution Systems                               8vo,  *3 50
+
+Geerligs, H. C. P. Cane Sugar and Its Manufacture            8vo,  *5 00
+
+Geikie, J. Structural and Field Geology                      8vo,  *4 00
+
+---- Mountains. Their Growth, Origin and Decay               8vo,  *4 00
+
+---- The Antiquity of Man in Europe                          8vo,  *3 00
+
+Georgi, F., and Schubert, A. Sheet Metal Working.
+  Trans. by C. Salter                                        8vo,   3 00
+
+Gerhard, W. P. Sanitation, Watersupply and Sewage
+  Disposal of Country Houses                                12mo,  *2 00
+
+---- Gas Lighting  (Science Series No. 111.)                16mo,   0 50
+
+---- Household Wastes. (Science Series No. 97.)             16mo,   0 50
+
+---- House Drainage. (Science Series No. 63.)               16mo,   0 50
+
+---- Sanitary Drainage of Buildings. (Science Series
+  No. 93.)                                                  16mo,   0 50
+
+Gerhardi, C. W. H. Electricity Meters                        8vo,  *4 00
+
+Geschwind, L. Manufacture of Alum and Sulphates.
+  Trans. by C. Salter                                        8vo,  *5 00
+
+Gibbings, A. H. Oil Fuel Equipment for Locomotives           8vo,  *5 00
+
+Gibbs, W. E. Lighting by Acetylene                          12mo,  *1 50
+
+Gibson, A. H. Hydraulics and Its Application                 8vo,  *5 00
+
+---- Water Hammer in Hydraulic Pipe Lines                   12mo,  *2 00
+
+Gibson, A. H., and Ritchie, E. G. Circular
+  Arc Bow Girder                                             4to,  *3 50
+
+Gilbreth, F. B. Motion Study                                12mo,  *2 00
+
+---- Bricklaying System                                      8vo,  *3 00
+
+---- Field System                                  12mo, leather,  *3 00
+
+---- Primer of Scientific Management                        12mo,  *1 00
+
+Gillette, H. P. Handbook of Cost Data              12mo, leather,  *5 00
+
+---- Rock Excavation Methods and Cost                       12mo,  *5 00
+
+---- and Dana, R. T. Cost Keeping and Management
+  Engineering                                                8vo,  *3 50
+
+---- and Hill, C. S. Concrete Construction, Methods
+  and Cost                                                   8vo,  *5 00
+
+Gillmore, Gen. Q. A. Roads, Streets, and Pavements          12mo,   1 25
+
+Godfrey, E. Tables for Structural Engineers        16mo, leather,  *2 50
+
+Golding, H. A. The Theta-Phi Diagram                        12mo,  *1 25
+
+Goldschmidt, R. Alternating Current Commutator Motor         8vo,  *3 00
+
+Goodchild, W. Precious Stones. (Westminster Series.)         8vo,  *2 00
+
+Goodeve, T. M. Textbook on the Steam-engine                 12mo,   2 00
+
+Gore, G. Electrolytic Separation of Metals                   8vo,  *3 50
+
+Gould, E. S. Arithmetic of the Steam-engine                 12mo,   1 00
+
+---- Calculus. (Science Series No. 112.)                    16mo,   0 50
+
+---- High Masonry Dams. (Science Series No. 22.)            16mo,   0 50
+
+Gould, E. S. Practical Hydrostatics and Hydrostatic
+  Formulas. (Science Series No. 117.)                       16mo,   0 50
+
+Gratacap, L. P. A Popular Guide to Minerals                  8vo,  *3 00
+
+Gray, J. Electrical Influence Machines                      12mo,   2 00
+
+---- Marine Boiler Design                                   12mo,  *1 25
+
+Greenhill, G. Dynamics of Mechanical Flight                  8vo,  *2 50
+
+Gregorius, R. Mineral Waxes. Trans. by C. Salter            12mo,  *3 00
+
+Grierson, R. Some Modern Methods of Ventilation              8vo,  *3 00
+
+Griffiths, A. B. A Treatise on Manures                      12mo,   3 00
+
+---- Dental Metallurgy                                       8vo,  *3 50
+
+Gross, E. Hops                                               8vo,  *4 50
+
+Grossman, J. Ammonia and Its Compounds                      12mo,  *1 25
+
+Groth, L. A. Welding and Cutting Metals by Gases or
+  Electricity. (Westminster Series)                          8vo,  *2 00
+
+Grover, F. Modern Gas and Oil Engines                        8vo,  *2 00
+
+Gruner, A. Power-loom Weaving                                8vo,  *3 00
+
+Güldner, Hugo. Internal Combustion Engines. Trans.
+  by H. Diederichs                                           4to, *15 00
+
+Gunther, C. O. Integration                                   8vo,  *1 25
+
+Gurden, R. L. Traverse Tables                folio, half morocco,  *7 50
+
+Guy, A. E. Experiments on the Flexure of Beams               8vo,  *1 25
+
+
+Haenig, A. Emery and Emery Industry                          8vo,  *2 50
+
+Hainbach, R. Pottery Decoration. Trans. by C. Salter        12mo,  *3 00
+
+Hale, W. J. Calculations of General Chemistry               12mo,  *1 00
+
+Hall, C. H. Chemistry of Paints and Paint Vehicles          12mo,  *2 00
+
+Hall, G. L. Elementary Theory of Alternate Current
+  Working                                                    8vo,  *1 50
+
+Hall, R. H. Governors and Governing Mechanism               12mo,  *2 00
+
+Hall, W. S. Elements of the Differential and Integral
+  Calculus                                                   8vo,  *2 25
+
+---- Descriptive Geometry             8vo volume and a 4to atlas,  *3 50
+
+Haller, G. F., and Cunningham, E. T. The Tesla Coil         12mo,  *1 25
+
+Halsey, F. A. Slide Valve Gears                             12mo,   1 50
+
+---- The Use of the Slide Rule. (Science Series No.
+  114.)                                                     16mo,   0 50
+
+---- Worm and Spiral Gearing. (Science Series No.
+  116.)                                                     16mo,   0 50
+
+Hancock, H. Textbook of Mechanics and Hydrostatics           8vo,   1 50
+
+Hancock, W. C. Refractory Materials. (Metallurgy
+  Series.)                                                 (_In Press._)
+
+Hardy, E. Elementary Principles of Graphic Statics          12mo,  *1 50
+
+Haring, H. Engineering Law
+    Vol. I. Law of Contract                                  8vo,  *4 00
+
+Harper, J. H. Hydraulic Tables on the Flow of Water         16mo,  *2 00
+
+Harris, S. M. Practical Topographical Surveying            (_In Press._)
+
+Harrison, W. B. The Mechanics' Tool-book                    12mo,   1 50
+
+Hart, J. W. External Plumbing Work                           8vo,  *3 00
+
+---- Hints to Plumbers on Joint Wiping                       8vo,  *3 00
+
+---- Principles of Hot Water Supply                          8vo,  *3 00
+
+---- Sanitary Plumbing and Drainage                          8vo,  *3 00
+
+Haskins, C. H. The Galvanometer and Its Uses                16mo,   1 50
+
+Hatt, J. A. H. The Colorist                          square 12mo,  *1 50
+
+Hausbrand, E. Drying by Means of Air and Steam.
+  Trans. by A. C. Wright                                    12mo,  *2 00
+
+---- Evaporating, Condensing and Cooling Apparatus.
+  Trans. by A. C. Wright                                     8vo,  *5 00
+
+Hausmann, E. Telegraph Engineering                           8vo,  *3 00
+
+Hausner, A. Manufacture of Preserved Foods and
+  Sweetmeats. Trans. by A. Morris and H. Robson              8vo,  *3 00
+
+Hawkesworth, J. Graphical Handbook for Reinforced
+  Concrete Design.                                           4to,  *2 50
+
+Hay, A. Continuous Current Engineering                       8vo,  *2 50
+
+Hayes, H. V. Public Utilities, Their Cost New and
+  Depreciation                                               8vo,  *2 00
+
+---- Public Utilities, Their Fair Present Value and
+  Return                                                     8vo,  *2 00
+
+Heath, F. H. Chemistry of Photography 8vo.                 (_In Press._)
+
+Heather, H. J. S. Electrical Engineering                     8vo,  *3 50
+
+Heaviside, O. Electromagnetic Theory. Vols. I and II   8vo, each,  *5 00
+                                     Vol. III                8vo,  *7 50
+
+Heck, R. C. H. The Steam Engine and Turbine                  8vo,  *3 50
+
+---- Steam-Engine and Other Steam Motors. Two Volumes.
+    Vol. I. Thermodynamics and the Mechanics                 8vo,  *3 50
+    Vol. II. Form, Construction, and Working                 8vo,  *5 00
+
+---- Notes on Elementary Kinematics                  8vo, boards,  *1 00
+
+---- Graphics of Machine Forces                      8vo, boards,  *1 00
+
+Heermann, P. Dyers' Materials. Trans. by A. C.
+  Wright                                                    12mo,  *2 50
+
+Heidenreich, E. L. Engineers' Pocketbook of Reinforced
+  Concrete                                         16mo, leather,  *3 00
+
+Hellot, Macquer and D'Apligny. Art of Dyeing Wool, Silk
+  and Cotton                                                 8vo,  *2 00
+
+Henrici, O. Skeleton Structures                              8vo,   1 50
+
+Hering, C., and Getman, F. H. Standard Tables of
+  Electro-Chemical Equivalents                              12mo,  *1 50
+
+Hering, D. W. Essentials of Physics for College
+  Students                                                   8vo,  *1 75
+
+Hering-Shaw, A. Domestic Sanitation and Plumbing.
+  Two Vols.                                                  8vo,  *5 00
+
+Hering-Shaw, A. Elementary Science                           8vo,  *2 00
+
+Herington, C. F. Powdered Coal and Fuel                    (_In Press._)
+
+Herrmann, G. The Graphical Statics of Mechanism.
+  Trans. by A. P. Smith                                     12mo,   2 00
+
+Herzfeld, J. Testing of Yarns and Textile Fabrics            8vo,  *3 50
+
+Hildebrandt, A. Airships, Past and Present                   8vo,  *3 50
+
+Hildenbrand, B. W. Cable-Making. (Science Series No. 32.)   16mo,   0 50
+
+Hilditch, T. P. A Concise History of Chemistry              12mo,  *1 25
+
+Hill, C. S. Concrete Inspection                             16mo,  *1 00
+
+Hill, J. W. The Purification of Public Water Supplies.
+  New Edition                                              (_In Press._)
+
+---- Interpretation of Water Analysis                      (_In Press._)
+
+Hill, M. J. M. The Theory of Proportion                      8vo,  *2 50
+
+Hiroi, I. Plate Girder Construction. (Science Series
+  No. 95.)                                                  16mo,   0 50
+
+---- Statically-Indeterminate Stresses                      12mo,  *2 00
+
+Hirshfeld, C. F. Engineering Thermodynamics. (Science
+  Series No. 45.)                                           16mo,   0 50
+
+Hoar, A. The Submarine Torpedo Boat                         12mo,  *2 00
+
+Hobart, H. M. Heavy Electrical Engineering                   8vo,  *4 50
+
+---- Design of Static Transformers                          12mo,  *2 00
+
+---- Electricity                                             8vo,  *2 00
+
+---- Electric Trains                                         8vo,  *2 50
+
+---- Electric Propulsion of Ships                            8vo,  *2 50
+
+Hobart, J. F. Hard Soldering, Soft Soldering and Brazing.   12mo,  *1 00
+
+Hobbs, W. R. P. The Arithmetic of Electrical Measurements.  12mo,   0 50
+
+Hoff, J. N. Paint and Varnish Facts and Formulas.           12mo,  *1 50
+
+Hole, W. The Distribution of Gas.                            8vo,  *7 50
+
+Holley, A. L. Railway Practice.                            folio,   6 00
+
+Hopkins, N. M. Model Engines and Small Boats.               12mo,   1 25
+
+Hopkinson, J., Shoolbred, J. N., and Day, R. E.
+  Dynamic Electricity. (Science Series No. 71.)             16mo,   0 50
+
+Horner, J. Practical Ironfounding.                           8vo,  *2 00
+
+---- Gear Cutting, in Theory and Practice.                   8vo,  *3 00
+
+Houghton, C. E. The Elements of Mechanics of Materials.     12mo,  *2 00
+
+Houstoun, R. A. Studies in Light Production.                12mo,   2 00
+
+Hovenden, F. Practical Mathematics for Young Engineers.     12mo,  *1 50
+
+Howe, G. Mathematics for the Practical Man.                 12mo,  *1 25
+
+Howorth, J. Repairing and Riveting Glass, China
+  and Earthenware.                                    8vo, paper,  *0 50
+
+Hoyt, W. E. Chemistry by Experimentation.                    8vo,  *0 70
+
+Hubbard, E. The Utilization of Wood-waste.                   8vo,  *2 00
+
+Hübner, J. Bleaching and Dyeing of Vegetable and
+  Fibrous Materials. (Outlines of Industrial Chemistry.)     8vo,  *5 00
+
+Hudson, O. F. Iron and Steel. (Outlines of Industrial
+  Chemistry.)                                                8vo,  *2 00
+
+Humphrey, J. C. W. Metallography of Strain. (Metallurgy
+  Series.)                                                 (_In Press._)
+
+Humphreys, A. C. The Business Features of Engineering
+  Practice.                                                  8vo,  *1 25
+
+Hunter, A. Bridge Work. 8vo.                               (_In Press._)
+
+Hurst. G. H. Handbook of the Theory of Color.                8vo,  *2 50
+
+---- Dictionary of Chemicals and Raw Products.               8vo,  *4 50
+
+---- Lubricating Oils, Fats and Greases.                     8vo,  *4 00
+
+---- Soaps.                                                  8vo,  *5 00
+
+Hurst, G. H., and Simmons, W. H. Textile Soaps and Oils.     8vo,   3 00
+
+Hurst, H. E., and Lattey, R. T. Text-book of Physics.        8vo,  *3 00
+
+---- Also published in three parts.
+    Part   I. Dynamics and Heat.                                   *1 25
+    Part  II. Sound and Light.                                     *1 25
+    Part III. Magnetism and Electricity.                           *1 50
+
+Hutchinson, R. W., Jr. Long Distance Electric Power
+  Transmission.                                             12mo,  *3 00
+
+Hutchinson, R. W., Jr., and Thomas, W. A. Electricity
+  in Mining.                                         12mo, (_In Press._)
+
+Hutchinson, W. B. Patents and How to Make Money Out
+  of Them.                                                  12mo,   1 00
+
+Hutton, W. S. The Works' Manager's Handbook.                 8vo,   6 00
+
+Hyde, E. W. Skew Arches. (Science Series No. 15.)           16mo,   0 50
+
+Hyde, F. S. Solvents, Oils, Gums, Waxes.                     8vo,  *2 00
+
+
+Induction Coils. (Science Series No. 53.)                   16mo,   0 50
+
+Ingham, A. E. Gearing. A practical treatise.                 8vo,  *2 50
+
+Ingle, H. Manual of Agricultural Chemistry.                  8vo,  *3 00
+
+Inness, C. H. Problems in Machine Design.                   12mo,  *2 00
+
+---- Air Compressors and Blowing Engines.                   12mo,  *2 00
+
+---- Centrifugal Pumps.                                     12mo,  *2 00
+
+---- The Fan.                                               12mo,  *2 00
+
+
+Jacob, A., and Gould, E. S. On the Designing and
+  Construction of Storage Reservoirs. (Science Series
+  No. 6)                                                    16mo,   0 50
+
+Jannettaz, E. Guide to the Determination of
+  Rocks. Trans. by G. W. Plympton.                          12mo,   1 50
+
+Jehl, F. Manufacture of Carbons.                             8vo,  *4 00
+
+Jennings, A. S. Commercial Paints and Paintings.
+  (Westminster Series.)                                      8vo,  *2 00
+
+Jennison, F. H. The Manufacture of Lake Pigments.            8vo,  *3 00
+
+Jepson, G. Cams and the Principles of their Construction.    8vo,  *1 50
+
+---- Mechanical Drawing.                        8vo. (_In Preparation._)
+
+Jervis-Smith, F. J. Dynamometers.                            8vo,  *3 50
+
+Jockin, W. Arithmetic of the Gold and Silversmith.          12mo,  *1 00
+
+Johnson, J. H. Arc Lamps and Accessory Apparatus.
+  (Installation Manuals Series.)                            12mo,  *0 75
+
+Johnson, T. M. Ship Wiring and Fitting. (Installation
+  Manuals Series.)                                          12mo,  *0 75
+
+Johnson, W. McA. The Metallurgy of Nickel.           (_In Preparation._)
+
+Johnston, J. F. W., and Cameron, C. Elements of
+  Agricultural Chemistry and Geology.                       12mo,   2 60
+
+Joly, J. Radioactivity and Geology.                         12mo,  *3 00
+
+Jones, H. C. Electrical Nature of Matter
+  and Radioactivity.                                        12mo,  *2 00
+
+---- Nature of Solution.                                     8vo,  *3 50
+
+---- New Era in Chemistry.                                  12mo,  *2 00
+
+Jones, J. H. Tinplate Industry.                              8vo,  *3 00
+
+Jones, M. W. Testing Raw Materials Used in Paint.           12mo,  *2 00
+
+Jordan, L. C. Practical Railway Spiral.            12mo, leather,  *1 50
+
+Joynson, F. H. Designing and Construction of
+  Machine Gearing.                                           8vo,   2 00
+
+Jüptner, H. F. V. Siderology: The Science of Iron.           8vo,  *5 00
+
+
+Kapp, G. Alternate Current Machinery. (Science
+  Series No. 96.)                                           16mo,   0 50
+
+Kapper, F. Overhead Transmission Lines.                      4to,  *4 00
+
+Keim, A. W. Prevention of Dampness in Buildings.             8vo,  *2 00
+
+Keller, S. S. Mathematics for Engineering Students.  12mo, half leather.
+
+---- and Knox, W. E. Analytical Geometry and Calculus.             *2 00
+
+Kelsey, W. R. Continuous-current Dynamos and Motors.         8vo,  *2 50
+
+Kemble, W. T., and Underhill, C. R. The Periodic Law
+  and the Hydrogen Spectrum.                          8vo, paper,  *0 50
+
+Kennedy, A. B. W., and Thurston, R. H. Kinematics of
+  Machinery. (Science Series No. 54.)                       16mo,   0 50
+
+Kennedy, A. B. W., Unwin, W. C., and Idell,
+  F. E. Compressed Air. (Science Series No. 106.)           16mo,   0 50
+
+Kennedy, R. Electrical Installations. Five Volumes.          4to,  15 00
+    Single Volumes.                                         each,   3 50
+
+---- Flying Machines; Practice and Design.                  12mo,  *2 00
+
+---- Principles of Aeroplane Construction.                   8vo,  *1 50
+
+Kennelly, A. E. Electro-dynamic Machinery.                   8vo,   1 50
+
+Kent, W. Strength of Materials. (Science Series No. 41.)    16mo,   0 50
+
+Kershaw, J. B. C. Fuel, Water and Gas Analysis.              8vo,  *2 50
+
+---- Electrometallurgy. (Westminster Series.)                8vo,  *2 00
+
+---- The Electric Furnace in Iron and Steel Production.     12mo,  *1 50
+
+---- Electro-Thermal Methods of Iron and Steel Production.   8vo,  *3 00
+
+Kindelan, J. Trackman's Helper.                             12mo,   2 00
+
+Kinzbrunner, C. Alternate Current Windings.                  8vo,  *1 50
+
+---- Continuous Current Armatures.                           8vo,  *1 50
+
+---- Testing of Alternating Current Machines.                8vo,  *2 00
+
+Kirkaldy, A. W., and Evans, A. D. History and
+  Economics of Transport.                                    8vo,  *3 00
+
+Kirkaldy, W. G. David Kirkaldy's System of
+  Mechanical Testing.                                        4to,  10 00
+
+Kirkbride, J. Engraving for Illustration.                    8vo,  *1 50
+
+Kirkham, J. E. Structural Engineering.                       8vo,  *5 00
+
+Kirkwood, J. P. Filtration of River Waters.                  4to,   7 50
+
+Kirschke, A. Gas and Oil Engines.                           12mo,  *1 25
+
+Klein, J. F. Design of a High-speed Steam-engine.            8vo,  *5 00
+
+---- Physical Significance of Entropy.                       8vo,  *1 50
+
+Klingenberg, G. Large Electric Power Stations.               4to,  *5 00
+
+Knight, R.-Adm. A. M. Modern Seamanship.                     8vo,  *6 50
+
+Knott, C. G., and Mackay, J. S. Practical Mathematics.       8vo,   2 00
+
+Knox, G. D. Spirit of the Soil.                             12mo,  *1 25
+
+Knox, J. Physico-Chemical Calculations.                     12mo,  *1 25
+
+---- Fixation of Atmospheric Nitrogen. (Chemical
+  Monographs.)                                              12mo,  *0 75
+
+Koester, F. Steam-Electric Power Plants.                     4to,  *5 00
+
+---- Hydroelectric Developments and Engineering.             4to,  *5 00
+
+Koller, T. The Utilization of Waste Products.                8vo,  *3 00
+
+---- Cosmetics.                                              8vo,  *2 50
+
+Koppe, S. W. Glycerine.                                     12mo,  *2 50
+
+Kozmin, P. A. Flour Milling. Trans. by M. Falkner.    8vo. (_In Press._)
+
+Kremann, R. Application of the Physico-Chemical
+  Theory to Technical Processes and Manufacturing Methods.
+  Trans. by H. E. Potts.                                     8vo,  *3 00
+
+Kretchmar, K. Yarn and Warp Sizing.                          8vo,  *4 00
+
+
+Lallier, E. V. Elementary Manual of the Steam Engine.       12mo,  *2 00
+
+Lambert, T. Lead and Its Compounds.                          8vo,  *3 50
+
+---- Bone Products and Manures.                              8vo,  *3 00
+
+Lamborn, L. L. Cottonseed Products.                          8vo,  *3 00
+
+---- Modern Soaps, Candles, and Glycerin.                    8vo,  *7 50
+
+Lamprecht, R. Recovery Work After Pit Fires. Trans.
+  by C. Salter.                                              8vo,  *4 00
+
+Lancaster, M. Electric Cooking, Heating and Cleaning.        8vo,  *1 00
+
+Lanchester, F. W. Aerial Flight. Two Volumes.                8vo.
+    Vol. I. Aerodynamics.                                          *6 00
+    Vol. II. Aerodonetics.                                         *6 00
+
+Lanchester, F. W. The Flying Machine.                        8vo,  *3 00
+
+Lange, K. R. By-Products of Coal-Gas Manufacture.           12mo,   2 00
+
+Larner, E. T. Principles of Alternating Currents.           12mo,  *1 25
+
+La Rue, B. F. Swing Bridges. (Science Series No. 107.)      16mo,   0 50
+
+Lassar-Cohn. Dr. Modern Scientific Chemistry. Trans.
+  by M. M. Pattison Muir                                    12mo,  *2 00
+
+Latimer, L. H., Field, C. J., and Howell, J. W.
+  Incandescent Electric Lighting. (Science
+  Series No. 57.)                                           16mo,   0 50
+
+Latta, M. N. Handbook of American Gas-Engineering Practice.  8vo,  *4 50
+
+---- American Producer Gas Practice.                         4to,  *6 00
+
+Laws, B. C. Stability and Equilibrium of Floating Bodies.    8vo,  *3 50
+
+Lawson, W. R. British Railways. A Financial and
+  Commercial Survey.                                         8vo,   2 00
+
+Leask, A. R. Breakdowns at Sea.                             12mo,   2 00
+
+---- Refrigerating Machinery.                               12mo,   2 00
+
+Lecky, S. T. S. "Wrinkles" in Practical Navigation.          8vo,  10 00
+
+Le Doux, M. Ice-Making Machines. (Science Series No. 46.)   16mo,   0 50
+
+Leeds, C. C. Mechanical Drawing for Trade Schools. oblong    4to,  *2 00
+
+---- Mechanical Drawing for High and Vocational Schools.     4to,  *1 25
+
+Lefévre, L. Architectural Pottery. Trans. by H. K.
+  Bird and W. M. Binns.                                      4to,  *7 50
+
+Lehner, S. Ink Manufacture. Trans. by A. Morris
+  and H. Robson.                                             8vo,  *2 50
+
+Lemstrom, S. Electricity in Agriculture and Horticulture.    8vo,  *1 50
+
+Letts, E. A. Fundamental Problems in Chemistry.              8vo,  *2 00
+
+Le Van, W. B. Steam-Engine Indicator. (Science
+  Series No. 78.)                                           16mo,   0 50
+
+Lewes, V. B. Liquid and Gaseous Fuels. (Westminster
+  Series.)                                                   8vo,  *2 00
+
+---- Carbonization of Coal.                                  8vo,  *3 00
+
+Lewis, L. P. Railway Signal Engineering.                     8vo,  *3 50
+
+Lewis Automatic Machine Rifle; Operation of.                16mo,  *0 75
+
+Licks, H. E. Recreations in Mathematics.                    12mo,  *1 25
+
+Lieber, B. F. Lieber's Five Letter Standard
+  Telegraphic Code.                                          8vo, *10 00
+
+---- Code. German Edition.                                   8vo, *10 00
+
+---- ---- Spanish Edition.                                   8vo, *10 00
+
+---- ---- French Edition.                                    8vo, *10 00
+
+---- Terminal Index.                                         8vo,  *2 50
+
+---- Lieber's Appendix.                                    folio, *15 00
+
+---- ---- Handy Tables.                                      4to,  *2 50
+
+---- Bankers and Stockbrokers' Code and Merchants
+  and Shippers' Blank Tables.                                8vo, *15 00
+
+---- 100,000,000 Combination Code.                           8vo, *10 00
+
+---- Engineering Code.                                       8vo, *12 50
+
+Livermore, V. P., and Williams, J. How to Become
+  a Competent Motorman                                      12mo,  *1 00
+
+Livingstone, R. Design and Construction of Commutators.      8vo,  *2 25
+
+---- Mechanical Design and Construction of Generators.       8vo,  *3 50
+
+Lloyd, S. L. Fertilizer Materials.                         (_In Press._)
+
+Lobben, P. Machinists' and Draftsmen's Handbook.             8vo,   2 50
+
+Lockwood, T. D. Electricity, Magnetism, and
+  Electro-telegraph.                                         8vo,   2 50
+
+---- Electrical Measurement and the Galvanometer.           12mo,   0 75
+
+Lodge, O. J. Elementary Mechanics.                          12mo,   1 50
+
+---- Signalling Across Space without Wires.                  8vo,  *2 00
+
+Loewenstein, L. C., and Crissey, C. P. Centrifugal Pumps.          *4 50
+
+Lomax, J. W. Cotton Spinning.                               12mo,   1 50
+
+Lord, R. T. Decorative and Fancy Fabrics.                    8vo,  *3 50
+
+Loring, A. E. A Handbook of the Electromagnetic Telegraph.  16mo,   0 50
+
+---- Handbook. (Science Series No. 39.)                     16mo,   0 50
+
+Lovell, D. H. Practical Switchwork.                         12mo,  *1 00
+
+Low, D. A. Applied Mechanics (Elementary).                  16mo,   0 80
+
+Lubschez, B. J. Perspective.                                12mo,  *1 50
+
+Lucke, C. E. Gas Engine Design.                              8vo,  *3 00
+
+---- Power Plants: Design, Efficiency, and Power
+  Costs. 2 vols.                                     (_In Preparation._)
+
+Luckiesh, M. Color and Its Application.                      8vo,  *3 00
+
+---- Light and Shade and Their Applications.                 8vo,  *2 50
+
+Lunge, G. Coal-tar and Ammonia. Three Volumes.               8vo, *20 00
+
+---- Technical Gas Analysis.                                 8vo,  *4 00
+
+---- Manufacture of Sulphuric Acid and Alkali. Four Volumes. 8vo,
+     Vol. I. Sulphuric Acid. In three parts.                       18 00
+---- Vol. I. Supplement.                                     8vo,   5 00
+     Vol. II. Salt Cake, Hydrochloric Acid and Leblanc
+       Soda. In two parts.                                        *15 00
+     Vol. III. Ammonia Soda.                                      *10 00
+     Vol. IV. Electrolytic Methods.                        (_In Press._)
+
+---- Technical Chemists' Handbook.                 12mo, leather,  *3 50
+
+---- Technical Methods of Chemical Analysis. Trans.
+       by C. A. Keane in collaboration with
+       the corps of specialists.
+     Vol. I. In two parts.                                   8vo, *15 00
+     Vol. II. In two parts.                                  8vo, *18 00
+     Vol. III. In two parts.                                 8vo, *18 00
+     The set (3 vols.) complete.                                  *50 00
+
+Luquer, L. M. Minerals in Rock Sections.                     8vo,  *1 50
+
+
+Macewen, H. A. Food Inspection.                              8vo,  *2 50
+
+Mackenzie, N. F. Notes on Irrigation Works.                  8vo,  *2 50
+
+Mackie, J. How to Make a Woolen Mill Pay.                    8vo,  *2 00
+
+Maguire, Wm. R. Domestic Sanitary Drainage and Plumbing.     8vo,   4 00
+
+Malcolm, C. W. Textbook on Graphic Statics.                  8vo,  *3 00
+
+Malcolm, H. W. Submarine Telegraph Cable.                  (_In Press._)
+
+Mallet, A. Compound Engines. Trans. by R. R. Buel.
+  (Science Series No. 10.)                                  16mo,
+
+Mansfield, A. N. Electro-magnets. (Science Series No. 64.)  16mo,   0 50
+
+Marks, E. C. R. Construction of Cranes and Lifting
+  Machinery.                                                12mo,  *1 50
+
+---- Construction and Working of Pumps.                     12mo,  *1 50
+
+---- Manufacture of Iron and Steel Tubes.                   12mo,  *2 00
+
+---- Mechanical Engineering Materials.                      12mo,  *1 00
+
+Marks, G. C. Hydraulic Power Engineering.                    8vo,   3 50
+
+---- Inventions, Patents and Designs.                       12mo,  *1 00
+
+Marlow, T. G. Drying Machinery and Practice.                 8vo,  *5 00
+
+Marsh, C. F. Concise Treatise on Reinforced Concrete.        8vo,  *2 50
+
+---- Reinforced Concrete Compression Member Diagram.
+  Mounted on Cloth Boards.                                         *1 50
+
+Marsh, C. F., and Dunn, W. Manual of Reinforced
+  Concrete and Concrete Block Construction.        16mo, morocco,  *2 50
+
+Marshall, W. J., and Sankey, H. R. Gas Engines.
+  (Westminster Series.)                                      8vo,  *2 00
+
+Martin, G. Triumphs and Wonders of Modern Chemistry.         8vo,  *2 00
+
+---- Modern Chemistry and Its Wonders.                       8vo,  *2 00
+
+Martin, N. Properties and Design of Reinforced Concrete.    12mo,  *2 50
+
+Martin, W. D. Hints to Engineers.                           12mo,  *1 50
+
+Massie, W. W., and Underhill, C. R. Wireless Telegraphy
+  and Telephony.                                            12mo,  *1 00
+
+Mathot, R. E. Internal Combustion Engines.                   8vo,  *4 00
+
+Maurice, W. Electric Blasting Apparatus and Explosives.      8vo,  *3 50
+
+---- Shot Firer's Guide.                                     8vo,  *1 50
+
+Maxwell, J. C. Matter and Motion. (Science Series No. 36.)  16mo,   0 50
+
+Maxwell, W. H., and Brown, J. T. Encyclopedia of
+  Municipal and Sanitary Engineering.                        4to, *10 00
+
+Mayer, A. M. Lecture Notes on Physics.                       8vo,   2 00
+
+Mayer, C., and Slippy, J. C. Telephone Line Construction.    8vo,  *3 00
+
+McCullough, E. Practical Surveying.                         12mo,  *2 00
+
+---- Engineering Work in Cities and Towns.                   8vo,  *3 00
+
+---- Reinforced Concrete.                                   12mo,  *1 50
+
+McCullough, R. S. Mechanical Theory of Heat.                 8vo,   3 50
+
+McGibbon, W. C. Indicator Diagrams for Marine Engineers.     8vo,  *3 00
+
+---- Marine Engineers' Drawing Book.                  oblong 4to,  *2 50
+
+McIntosh, J. G. Technology of Sugar.                         8vo,  *5 00
+
+---- Industrial Alcohol.                                     8vo,  *3 00
+
+---- Manufacture of Varnishes and Kindred Industries.
+      Three Volumes.                                         8vo.
+    Vol. I. Oil Crushing, Refining and Boiling.                    *3 50
+    Vol. II. Varnish Materials and Oil Varnish Making.             *4 00
+    Vol. III. Spirit Varnishes and Materials.                      *4 50
+
+McKnight, J. D., and Brown, A. W. Marine Multitubular Boilers.     *1 50
+
+McMaster, J. B. Bridge and Tunnel Centres. (Science
+  Series No. 20.)                                           16mo,   0 50
+
+McMechen, F. L. Tests for Ores, Minerals and Metals.        12mo,  *1 00
+
+McPherson, J. A. Water-works Distribution.                   8vo,   2 50
+
+Meade, A. Modern Gas Works Practice.                         8vo,  *7 50
+
+McGibbon, W. C. Marine Engineers Pocketbook.                12mo,  *4 00
+
+Meade, R. K. Design and Equipment of Small Chemical
+  Laboratories,                                              8vo,
+
+Melick, C. W. Dairy Laboratory Guide.                       12mo,  *1 25
+
+Mensch, L. J. Reinforced Concrete Pocket Book.     16mo, leather,  *4 00
+
+Merck, E. Chemical Reagents; Their Purity and Tests. Trans.
+  by H. E. Schenck.                                          8vo,   1 00
+
+Merivale, J. H. Notes and Formulae for Mining Students.     12mo,   1 50
+
+Merritt, Wm. H. Field Testing for Gold and Silver. 16mo, leather,   1 50
+
+Mierzinski, S. Waterproofing of Fabrics. Trans. by A.
+  Morris and H. Robson.                                      8vo,  *2 50
+
+Miessner, B. F. Radio Dynamics.                             12mo,  *2 00
+
+Miller, G. A. Determinants. (Science Series No. 105.)       16mo,
+
+Miller, W. J. Introduction to Historical Geology.           12mo,  *2 00
+
+Milroy, M. E. W. Home Lace-making.                          12mo,  *1 00
+
+Mills, C. N. Elementary Mechanics for Engineers.             8vo,  *1 00
+
+Mitchell, C. A. Mineral and Aerated Waters.                  8vo,  *3 00
+
+Mitchell, C. A., and Prideaux, R. M. Fibres Used in
+  Textile and Allied Industries.                             8vo,  *3 00
+
+Mitchell, C. F., and G. A. Building Construction
+       and Drawing.                                         12mo.
+     Elementary Course.                                            *1 50
+     Advanced Course.                                              *2 50
+
+Monckton, C. C. F. Radiotelegraphy. (Westminster Series.)    8vo,  *2 00
+
+Monteverde, R. D. Vest Pocket Glossary of English-Spanish,
+  Spanish-English Technical Terms.                 64mo, leather,  *1 00
+
+Montgomery, J. H. Electric Wiring Specifications.           16mo,  *1 00
+
+Moore, E. C. S. New Tables for the Complete Solution of
+  Ganguillet and Kutter's Formula.                           8vo,  *5 00
+
+Morecroft, J. H., and Hehre, F. W. Short Course
+  in Electrical Testing.                                     8vo,  *1 50
+
+Morgan, A. P. Wireless Telegraph Apparatus for Amateurs.    12mo,  *1 50
+
+Moses, A. J. The Characters of Crystals.                     8vo,  *2 00
+
+---- and Parsons, C. L. Elements of Mineralogy.              8vo,  *3 00
+
+Moss, S. A. Elements of Gas Engine Design. (Science
+  Series No. 121.)                                          16mo,   0 50
+
+---- The Lay-out of Corliss Valve Gears. (Science
+  Series No. 119.)                                          16mo,   0 50
+
+Mulford, A. C. Boundaries and Landmarks.                    12mo,  *1 00
+
+Mullin, J. P. Modern Moulding and Pattern-making.           12mo,   2 50
+
+Munby, A. E. Chemistry and Physics of Building
+  Materials. (Westminster Series.)                           8vo,  *2 00
+
+Murphy, J. G. Practical Mining.                             16mo,   1 00
+
+Murray, J. A. Soils and Manures. (Westminster Series.)       8vo,  *2 00
+
+
+Nasmith, J. The Student's Cotton Spinning.                   8vo,   3 00
+
+---- Recent Cotton Mill Construction.                       12mo,   2 50
+
+Neave, G. B., and Heilbron, I. M. Identification of
+  Organic Compounds.                                        12mo,  *1 25
+
+Neilson, R. M. Aeroplane Patents.                            8vo,  *2 00
+
+Nerz, F. Searchlights. Trans. by C. Rodgers.                 8vo,  *3 00
+
+Neuberger, H., and Noalhat, H. Technology of Petroleum.
+  Trans. by J. G. McIntosh.                                  8vo, *10 00
+
+Newall, J. W. Drawing, Sizing and Cutting Bevel-gears.       8vo,   1 50
+
+Newell, F. H., and Drayer, C. E. Engineering
+  as a Career                                        12mo, cloth,  *1 00
+                                                           paper,   0 75
+
+Newbeging, T. Handbook for Gas Engineers and Managers.       8vo,  *6 50
+
+Nicol, G. Ship Construction and Calculations.                8vo,  *5 00
+
+Nipher, F. E. Theory of Magnetic Measurements.              12mo,   1 00
+
+Nisbet, H. Grammar of Textile Design                         8vo,  *3 00
+
+Nolan, H. The Telescope. (Science Series No. 51.)           16mo,   0 50
+
+North, H. B. Laboratory Experiments in General Chemistry    12mo,  *1 00
+
+Nugent, E. Treatise on Optics                               12mo,   1 50
+
+
+O'Connor, H. The Gas Engineer's Pocketbook         12mo, leather,   3 50
+
+Ohm, G. S., and Lockwood, T. D. Galvanic Circuit.
+  Translated by William Francis. (Science Series
+  No. 102.)                                                 16mo,   0 50
+
+Olsen, J. C. Text-book of Quantitative Chemical Analysis     8vo,   3 50
+
+Olsson, A. Motor Control, in Turret Turning and Gun
+  Elevating. (U. S. Navy Electrical Series, No. 1.)  12mo, paper,  *0 50
+
+Ormsby, M. T. M. Surveying                                  12mo,   1 50
+
+Oudin, M. A. Standard Polyphase Apparatus and Systems        8vo,  *3 00
+
+Owen, D. Recent Physical Research                            8vo,  *1 50
+
+
+Pakes, W. C. C., and Nankivell, A. T. The Science of
+  Hygiene                                                    8vo,  *1 75
+
+Palaz, A. Industrial Photometry. Trans. by G. W.
+  Patterson, Jr.                                             8vo,  *4 00
+
+Pamely, C. Colliery Manager's Handbook                       8vo, *10 00
+
+Parker, P. A. M. The Control of Water                        8vo,  *5 00
+
+Parr, G. D. A. Electrical Engineering Measuring
+  Instruments                                                8vo,  *3 50
+
+Parry, E. J. Chemistry of Essential Oils and
+  Artificial Perfumes,                                     (_In Press._)
+
+---- Foods and Drugs. Two Volumes.
+    Vol. I. Chemical and Microscopical Analysis
+      of Foods and Drugs                                           *7 50
+    Vol. II. Sale of Food and Drugs Act                            *3 00
+
+---- and Coste, J. H. Chemistry of Pigments                  8vo,  *4 50
+
+Parry, L. Notes on Alloys                                    8vo,  *3 00
+
+---- Metalliferous Wastes                                    8vo,  *2 00
+
+---- Analysis of Ashes and Alloys                            8vo,  *2 00
+
+Parry, L. A. Risk and Dangers of Various Occupations         8vo,  *3 00
+
+Parshall, H. F., and Hobart, H. M. Armature Windings         4to,  *7 50
+
+---- Electric Railway Engineering                            4to, *10 00
+
+Parsons, J. L. Land Drainage                                 8vo,  *1 50
+
+Parsons, S. J. Malleable Cast Iron                           8vo,  *2 50
+
+Partington, J. R. Higher Mathematics for Chemical Students  12mo,  *2 00
+
+---- Textbook of Thermodynamics                              8vo,  *4 00
+
+Passmore, A. C. Technical Terms Used in Architecture         8vo,  *3 50
+
+Patchell, W. H. Electric Power in Mines                      8vo,  *4 00
+
+Paterson, G. W. L. Wiring Calculations                      12mo,  *2 00
+
+---- Electric Mine Signalling Installations                 12mo,  *1 50
+
+Patterson, D. The Color Printing of Carpet Yarns             8vo,  *3 50
+
+---- Color Matching on Textiles                              8vo,  *3 00
+
+---- Textile Color Mixing                                    8vo,  *3 00
+
+Paulding, C. P. Condensation of Steam in Covered and
+  Bare Pipes                                                 8vo,  *2 00
+
+---- Transmission of Heat through Cold-storage Insulation   12mo,  *1 00
+
+Payne, D. W. Iron Founders' Handbook                         8vo,  *4 00
+
+Peckham, S. F. Solid Bitumens                                8vo,  *5 00
+
+Peddie, R. A. Engineering and Metallurgical Books           12mo,  *1 50
+
+Peirce, B. System of Analytic Mechanics                      4to,  10 00
+
+---- Linnear Associative Algebra                             4to,   3 00
+
+Pendred, V. The Railway Locomotive. (Westminster Series.)    8vo,  *2 00
+
+Perkin, F. M. Practical Methods of Inorganic
+  Chemistry                                                 12mo,  *1 00
+
+Perrin, J. Atoms                                             8vo,  *2 50
+
+---- and Jaggers, E. M. Elementary Chemistry                12mo,  *1 00
+
+Perrine, F. A. C. Conductors for Electrical
+  Distribution                                               8vo,  *3 50
+
+Petit, G. White Lead and Zinc White Paints                   8vo,  *1 50
+
+Petit, R. How to Build an Aeroplane. Trans. by
+  T. O'B. Hubbard, and J. H. Ledeboer                        8vo,  *1 50
+
+Pettit, Lieut. J. S. Graphic Processes. (Science
+  Series No. 76.)                                           16mo,   0 50
+
+Philbrick, P. H. Beams and Girders. (Science Series
+  No. 88.)                                                  16mo,
+
+Phillips, J. Gold Assaying                                   8vo,  *2 50
+
+---- Dangerous Goods                                         8vo,   3 50
+
+Phin, J. Seven Follies of Science                           12mo,  *1 25
+
+Pickworth, C. N. The Indicator Handbook. Two
+  Volumes                                             12mo, each,   1 50
+
+---- Logarithms for Beginners                       12mo, boards,   0 50
+
+---- The Slide Rule                                         12mo,   1 00
+
+Plattner's Manual of Blow-pipe Analysis. Eighth
+  Edition, revised. Trans. by H. B. Cornwall                 8vo,  *4 00
+
+Plympton, G. W. The Aneroid Barometer. (Science
+  Series No. 35.)                                           16mo,   0 50
+
+---- How to become an Engineer. (Science Series No.
+  100.)                                                     16mo,   0 50
+
+---- Van Nostrand's Table Book,  (Science Series No.
+  104.)                                                     16mo,   0 50
+
+Pochet, M. L. Steam Injectors. Translated from the
+  French. (Science Series No. 29.)                          16mo,   0 50
+
+Pocket Logarithms to Four Places. (Science Series No.
+  65.)                                                      16mo,   0 50
+                                                         leather,   1 00
+
+Polleyn, F. Dressings and Finishings for Textile
+  Fabrics                                                    8vo,  *3 00
+
+Pope, F. G. Organic Chemistry                               12mo,  *2 25
+
+Pope, F. L. Modern Practice of the Electric Telegraph        8vo,   1 50
+
+Popplewell, W. C. Prevention of Smoke                        8vo,  *3 50
+
+---- Strength of Materials                                   8vo,  *1 75
+
+Porritt, B. D. The Chemistry of Rubber. (Chemical
+  Monographs, No. 3.)                                       12mo,  *0 75
+
+Porter, J. R. Helicopter Flying Machine                     12mo,  *1 25
+
+Potts, H. E. Chemistry of the Rubber Industry.
+  (Outlines of Industrial Chemistry)                         8vo,  *2 50
+
+Practical Compounding of Oils, Tallow and Grease             8vo,  *3 50
+
+Pratt, K. Boiler Draught                                    12mo,  *1 25
+
+---- High Speed Steam Engines                                8vo,  *2 00
+
+Pray, T., Jr. Twenty Years with the Indicator                8vo,   2 50
+
+---- Steam Tables and Engine Constant                        8vo,   2 00
+
+Prelini, C. Earth and Rock Excavation                        8vo,  *3 00
+
+---- Graphical Determination of Earth Slopes                 8vo,  *2 00
+
+---- Tunneling. New Edition                                  8vo,  *3 00
+
+---- Dredging. A Practical Treatise                          8vo,  *3 00
+
+Prescott, A. B. Organic Analysis                             8vo,   5 00
+
+Prescott, A. B., and Johnson, O. C. Qualitative
+  Chemical Analysis                                          8vo,  *3 50
+
+Prescott, A. B., and Sullivan, E. C. First Book in
+  Qualitative Chemistry                                     12mo,  *1 50
+
+Prideaux, E. B. R. Problems in Physical Chemistry            8vo,  *2 00
+
+Primrose, G. S. C. Zinc. (Metallurgy Series.)              (_In Press._)
+
+Prince, G. T. Flow of Water                                 12mo,  *2 00
+
+Pullen, W. W. F. Application of Graphic Methods to
+  the Design of Structures                                  12mo,  *2 50
+
+---- Injectors: Theory, Construction and Working            12mo,  *1 50
+
+---- Indicator Diagrams                                      8vo,  *2 50
+
+---- Engine Testing                                          8vo,  *4 50
+
+Putsch, A. Gas and Coal-dust Firing                          8vo,  *3 00
+
+Pynchon, T. R. Introduction to Chemical Physics              8vo,   3 00
+
+
+Rafter G. W. Mechanics of Ventilation. (Science Series
+  No. 33.)                                                  16mo,   0 50
+
+---- Potable Water. (Science Series No. 103.)               16mo,   0 50
+
+---- Treatment of Septic Sewage. (Science Series
+  No. 118.)                                                 16mo,   0 50
+
+Rafter, G. W., and Baker, M. N. Sewage Disposal in
+  the United States.                                         4to,  *6 00
+
+Raikes, H. P. Sewage Disposal Works                          8vo,  *4 00
+
+Randau, P. Enamels and Enamelling                            8vo,  *4 00
+
+Rankine, W. J. M. Applied Mechanics                          8vo,   5 00
+
+---- Civil Engineering                                       8vo,   6 50
+
+---- Machinery and Millwork                                  8vo,   5 00
+
+---- The Steam-engine and Other Prime Movers                 8vo,   5 00
+
+Rankine, W. J. M., and Bamber, E. F. A Mechanical
+  Text-book                                                  8vo,   3 50
+
+Ransome, W. R. Freshman Mathematics                         12mo,  *1 35
+
+Raphael, F. C. Localization of Faults in Electric
+  Light and Power Mains                                      8vo,   3 50
+
+Rasch, E. Electric Arc Phenomena. Trans. by K. Tornberg      8vo,  *2 00
+
+Rateau, A. Flow of Steam through Nozzles and Orifices.
+  Trans. by H. B. Brydon                                     8vo,  *1 50
+
+Rathbone, R. L. B. Simple Jewellery                          8vo,  *2 00
+
+Rausenberger, F. The Theory of the Recoil of Guns            8vo,  *4 50
+
+Rautenstrauch, W. Notes on the Elements of Machine
+  Design                                             8vo, boards,  *1 50
+
+Rautenstrauch, W., and Williams, J. T. Machine Drafting
+  and Empirical Design.
+    Part I. Machine Drafting                                 8vo,  *1 25
+    Part II. Empirical Design                        (_In Preparation._)
+
+Raymond, E. B. Alternating Current Engineering              12mo,  *2 50
+
+Rayner, H. Silk Throwing and Waste Silk Spinning             8vo,  *2 50
+
+Recipes for the Color, Paint, Varnish, Oil, Soap and
+  Drysaltery Trades                                          8vo,  *3 50
+
+Recipes for Flint Glass Making                              12mo,  *4 50
+
+Redfern, J. B., and Savin, J. Bells, Telephones
+  (Installation Manuals Series.)                            16mo,  *0 50
+
+Redgrove, H. S. Experimental Mensuration                    12mo,  *1 25
+
+Redwood, B. Petroleum. (Science Series No. 92.)             16mo,   0 50
+
+Reed, S. Turbines Applied to Marine Propulsion                     *5 00
+
+Reed's Engineers' Handbook                                   8vo,  *6 00
+
+---- Key to the Nineteenth Edition of Reed's
+  Engineers' Handbook                                        8vo,  *3 00
+
+---- Useful Hints to Sea-going Engineers                    12mo,   1 50
+
+Reid, E. E. Introduction to Research in Organic
+  Chemistry                                                (_In Press._)
+
+Reid, H. A. Concrete and Reinforced Concrete
+  Construction                                               8vo,  *5 00
+
+Reinhardt, C. W. Lettering for Draftsmen, Engineers,
+  and Students                                oblong 4to, boards,   1 00
+
+Reinhardt, C. W. The Technic of Mechanical Drafting,
+                                             oblong, 4to, boards,  *1 00
+
+Reiser, F. Hardening and Tempering of Steel. Trans. by A.
+  Morris and H. Robson                                      12mo,  *2 50
+
+Reiser, N. Faults in the Manufacture of Woolen Goods.
+  Trans. by A. Morris and H. Robson                          8vo,  *2 50
+
+---- Spinning and Weaving Calculations                       8vo,  *5 00
+
+Renwick, W. G. Marble and Marble Working                     8vo,   5 00
+
+Reuleaux, F. The Constructor. Trans. by H. H. Suplee         4to,  *4 00
+
+Reuterdahl, A. Theory and Design of Reinforced
+  Concrete Arches.                                           8vo,  *2 00
+
+Rey, Jean. The Range of Electric Searchlight Projectors      8vo,  *4 50
+
+Reynolds, O., and Idell, F. E. Triple Expansion Engines.
+  (Science Series No. 99.)                                  16mo,   0 50
+
+Rhead, G. F. Simple Structural Woodwork                     12mo,  *1 00
+
+Rhodes, H. J. Art of Lithography                             8vo,   3 50
+
+Rice, J. M., and Johnson, W. W. A New Method of Obtaining
+  the Differential of Functions                             12mo,   0 50
+
+Richards, W. A. Forging of Iron and Steel                   12mo,   1 50
+
+Richards, W. A., and North, H. B. Manual of Cement Testing  12mo,  *1 50
+
+Richardson, J. The Modern Steam Engine                       8vo,  *3 50
+
+Richardson, S. S. Magnetism and Electricity                 12mo,  *2 00
+
+Rideal, S. Glue and Glue Testing                             8vo,  *4 00
+
+Rimmer, E. J. Boiler Explosions, Collapses and Mishaps       8vo,  *1 75
+
+Rings, F. Concrete in Theory and Practice                   12mo,  *2 50
+
+---- Reinforced Concrete Bridges                             4to,  *5 00
+
+Ripper, W. Course of Instruction in Machine Drawing        folio,  *6 00
+
+Roberts, F. C. Figure of the Earth. (Science Series
+  No. 79.)                                                  16mo,   0 50
+
+Roberts, J., Jr. Laboratory Work in Electrical Engineering   8vo,  *2 00
+
+Robertson, L. S. Water-tube Boilers                          8vo,   2 00
+
+Robinson, J. B. Architectural Composition                    8vo,  *2 50
+
+Robinson, S. W. Practical Treatise on the Teeth of Wheels.
+  (Science Series No. 24.)                                  16mo,   0 50
+
+---- Railroad Economics. (Science Series No. 59.)           16mo,   0 50
+
+---- Wrought Iron Bridge Members. (Science Series No. 60.)  16mo,   0 50
+
+Robson, J. H. Machine Drawing and Sketching                  8vo,  *1 50
+
+Roebling, J. A. Long and Short Span Railway Bridges        folio,  25 00
+
+Rogers, A. A Laboratory Guide of Industrial Chemistry      (_In Press._)
+
+---- Elements of Industrial Chemistry                       12mo,  *3 00
+
+---- Manual of Industrial Chemistry                          8vo,  *5 00
+
+Rogers, F. Magnetism of Iron Vessels. (Science Series
+  No. 30.).                                                 16mo,   0 50
+
+Rohland, P. Colloidal and Crystalloidal State of Matter.
+  Trans. by W. J. Britland and H. E. Potts                  12mo,  *1 25
+
+Rollinson, C. Alphabets                             Oblong, 12mo,  *1 00
+
+Rose, J. The Pattern-makers' Assistant                       8vo,   2 50
+
+---- Key to Engines and Engine-running                      12mo,   2 50
+
+Rose, T. K. The Precious Metals. (Westminster Series.)       8vo,  *2 00
+
+Rosenhain, W. Glass Manufacture. (Westminster Series.)       8vo,  *2 00
+
+---- Physical Metallurgy, An Introduction to. (Metallurgy
+  Series.)                                                   8vo,  *3 50
+
+Roth, W. A. Physical Chemistry                               8vo,  *2 00
+
+Rowan, F. J. Practical Physics of the Modern Steam-boiler    8vo,  *3 00
+
+---- and Idell, F. E. Boiler Incrustation and Corrosion.
+  (Science Series No. 27.)                                  16mo,   0 50
+
+Roxburgh, W. General Foundry Practice. (Westminster
+  Series.).                                                  8vo,  *2 00
+
+Ruhmer, E. Wireless Telephony. Trans. by J. Erskine-Murray.  8vo,  *3 50
+
+Russell, A. Theory of Electric Cables and Networks           8vo,  *3 00
+
+Rutley, F. Elements of Mineralogy                           12mo,  *1 25
+
+
+Sanford, P. G. Nitro-explosives                              8vo,  *4 00
+
+Saunders, C. H. Handbook of Practical Mechanics             16mo,   1 00
+                                                         leather,   1 25
+
+Sayers, H. M. Brakes for Tram Cars                           8vo,  *1 25
+
+Scheele, C. W. Chemical Essays                               8vo,  *2 00
+
+Scheithauer, W. Shale Oils and Tars                          8vo,  *3 50
+
+Scherer, R. Casein. Trans. by C. Salter                      8vo,  *3 00
+
+Schidrowitz, P. Rubber, Its Production and Industrial Uses   8vo,  *5 00
+
+Schindler, K. Iron and Steel Construction Works             12mo,  *1 25
+
+Schmall, C. N. First Course in Analytic Geometry,
+  Plane and Solid.                            12mo, half leather,  *1 75
+
+Schmeer, L. Flow of Water                                    8vo,  *3 00
+
+Schumann, F. A Manual of Heating and Ventilation   12mo, leather,   1 50
+
+Schwarz, E. H. L. Causal Geology                             8vo,  *2 50
+
+Schweizer, V. Distillation of Resins                         8vo,  *3 50
+
+Scott, W. W. Qualitative Analysis. A Laboratory Manual       8vo,  *1 50
+
+---- Standard Methods of Chemical Analysis                   8vo,  *6 00
+
+Scribner, J. M. Engineers' and Mechanics'
+  Companion                                        16mo, leather,   1 50
+
+Scudder, H. Electrical Conductivity and Ionization Constants
+  of Organic Compounds                                       8vo,  *3 00
+
+Searle, A. B. Modern Brickmaking                             8vo,  *5 00
+
+---- Cement, Concrete and Bricks                             8vo,  *3 00
+
+Searle, G. M. "Sumners' Method."  Condensed and Improved.
+  (Science Series No. 124.)                                 16mo,   0 50
+
+Seaton, A. E. Manual of Marine Engineering                   8vo,   8 00
+
+Seaton, A. E., and Rounthwaite, H. M. Pocket-book of
+  Marine Engineering                               16mo, leather,   3 50
+
+Seeligmann, T., Torrilhon, G. L., and Falconnet, H. India
+  Rubber and Gutta Percha. Trans. by J. G. McIntosh          8vo,  *5 00
+
+Seidell, A. Solubilities of Inorganic and Organic
+  Substances                                                 8vo,   4 50
+
+Seligman, B. Aluminum. (Metallurgy Series.)                (_In Press._)
+
+Sellew, W. H. Steel Rails                                    4to, *10 00
+
+---- Railway Maintenance Engineering                        12mo,  *2 50
+
+Senter, G. Outlines of Physical Chemistry                   12mo,  *1 75
+
+---- Text-book of Inorganic Chemistry                       12mo,  *1 75
+
+Sever, G. F. Electric Engineering Experiments        8vo, boards,  *1 00
+
+Sever, G. F., and Townsend, F. Laboratory and Factory
+  Tests in Electrical Engineering                            8vo,  *2 50
+
+Sewall, C. H. Wireless Telegraphy                            8vo,  *2 00
+
+---- Lessons in Telegraphy                                  12mo,  *1 00
+
+Sewell, T. The Construction of Dynamos                       8vo,  *3 00
+
+Sexton, A. H. Fuel and Refractory Materials                 12mo,  *2 50
+
+---- Chemistry of the Materials of Engineering              12mo,  *2 50
+
+---- Alloys (Non-Ferrous)                                    8vo,  *3 00
+
+Sexton, A. H., and Primrose, J. S. G. The Metallurgy of
+  Iron and Steel.                                            8vo,  *6 50
+
+Seymour, A. Modern Printing Inks                             8vo,  *2 00
+
+Shaw, Henry S. H. Mechanical Integrators. (Science
+  Series No. 83.)                                           16mo,   0 50
+
+Shaw, S. History of the Staffordshire Potteries              8vo,   2 00
+
+---- Chemistry of Compounds Used in Porcelain Manufacture    8vo,  *5 00
+
+Shaw, T. R. Driving of Machine Tools                        12mo,  *2 00
+
+Shaw, W. N. Forecasting Weather                              8vo,  *3 50
+
+Sheldon, S., and Hausmann, E. Direct Current Machines       12mo,  *2 50
+
+---- Alternating Current Machines                           12mo,  *2 50
+
+Sheldon, S., and Hausmann, E. Electric Traction and
+  Transmission Engineering                                  12mo,  *2 50
+
+---- Physical Laboratory Experiments, for Engineering
+  Students                                                   8vo,  *1 25
+
+Shields, J. E. Notes on Engineering Construction            12mo,   1 50
+
+Shreve, S. H. Strength of Bridges and Roofs                  8vo,   3 50
+
+Shunk, W. F. The Field Engineer                    12mo, morocco,   2 50
+
+Simmons, W. H., and Appleton, H. A. Handbook of
+  Soap Manufacture,                                          8vo,  *3 00
+
+Simmons, W. H., and Mitchell, C. A. Edible Fats and Oils     8vo,  *3 00
+
+Simpson, G. The Naval Constructor                  12mo, morocco,  *5 00
+
+Simpson, W. Foundations                               8vo. (_In Press._)
+
+Sinclair, A. Development of the Locomotive
+  Engine                                       8vo, half leather,   5 00
+
+Sindall, R. W. Manufacture of Paper. (Westminster Series.)   8vo,  *2 00
+
+Sindall, R. W., and Bacon, W. N. The Testing of Wood Pulp    8vo,  *2 50
+
+Sloane, T. O'C. Elementary Electrical Calculations          12mo,  *2 00
+
+Smallwood, J. C. Mechanical Laboratory Methods. (Van
+  Nostrand's Textbooks)                            12mo, leather,  *2 50
+
+Smith, C. A. M. Handbook of Testing, MATERIALS               8vo,  *2 50
+
+Smith, C. A. M., and Warren, A. G. New Steam Tables          8vo,  *1 25
+
+Smith, C. F. Practical Alternating Currents and Testing      8vo,  *2 50
+
+---- Practical Testing of Dynamos and Motors                 8vo,  *2 00
+
+Smith, F. A. Railway Curves                                 12mo,  *1 00
+
+---- Standard Turnouts on American Railroads                12mo,  *1 00
+
+---- Maintenance of Way Standards                           12mo,  *1 50
+
+Smith, F. E. Handbook of General Instruction for
+  Mechanics                                                 12mo,   1 50
+
+Smith, H. G. Minerals and the Microscope                    12mo,  *1 25
+
+Smith, J. C. Manufacture of Paint                            8vo,  *3 50
+
+Smith, R. H. Principles of Machine Work                     12mo,
+
+---- Advanced Machine Work                                  12mo,  *3 00
+
+Smith, W. Chemistry of Hat Manufacturing                    12mo,  *3 00
+
+Snell, A. T. Electric Motive Power                           8vo,  *4 00
+
+Snow, W. G. Pocketbook of Steam Heating and Ventilation.   (_In Press._)
+
+Snow, W. G., and Nolan, T. Ventilation of Buildings.
+  (Science Series No. 5.)                                   16mo,   0 50
+
+Soddy, F. Radioactivity                                      8vo,  *3 00
+
+Solomon, M. Electric Lamps. (Westminster Series.)            8vo,  *2 00
+
+Somerscales, A. N. Mechanics for Marine Engineers           12mo,  *2 00
+
+---- Mechanical and Marine Engineering Science               8vo,  *5 00
+
+Sothern, J. W. The Marine Steam Turbine                      8vo,  *6 00
+
+---- Verbal Notes and Sketches for Marine Engineers          8vo,  *7 50
+
+Sothern, J. W., and Sothern, R. M. Elementary
+  Mathematics for Marine Engineers                          12mo,  *1 50
+
+---- Simple Problems in Marine Engineering Design           12mo,  *1 50
+
+Southcombe, J. E. Chemistry of the Oil Industries.
+  (Outlines of Industrial Chemistry.)                        8vo,  *3 00
+
+Soxhlet, D. H. Dyeing and Staining Marble. Trans.
+  by A. Morris and H. Robson                                 8vo,  *2 50
+
+Spangenburg, L. Fatigue of Metals. Translated by
+  S. H. Shreve. (Science Series No. 23.)                    16mo,   0 50
+
+Specht, G. J., Hardy, A. S., McMaster, J. B., and
+  Walling. Topographical Surveying. (Science Series
+  No. 72.)                                                  16mo,   0 50
+
+Spencer, A. S. Design of Steel-Framed Sheds                  8vo,  *3 50
+
+Speyers, C. L. Text-book of Physical Chemistry               8vo,  *1 50
+
+Spiegel, L. Chemical Constitution and Physiological
+  Action. (Trans. by C. Luedeking and A. C. Boylston.)      12mo,  *1 25
+
+Sprague, E. H. Hydraulics                                   12mo,   1 50
+
+---- Elements of Graphic Statics                             8vo,   2 00
+
+---- Stability of Masonry                                   12mo,   1 50
+
+---- Elementary Mathematics for Engineers                   12mo,  *1 50
+
+Stahl, A. W. Transmission of Power. (Science Series
+  No. 28.)                                                  16mo,
+
+Stahl, A. W., and Woods, A. T. Elementary Mechanism         12mo,  *2 00
+
+Staley, C., and Pierson, G. S. The Separate System of
+  Sewerage                                                   8vo,  *3 00
+
+Standage, H. C. Leatherworkers' Manual                       8vo,  *3 50
+
+---- Sealing Waxes, Wafers, and Other Adhesives              8vo,  *2 00
+
+---- Agglutinants of all Kinds for all Purposes             12mo,  *3 50
+
+Stanley, H. Practical Applied Physics                      (_In Press._)
+
+Stansbie, J. H. Iron and Steel. (Westminster Series.)        8vo,  *2 00
+
+Steadman, F. M. Unit Photography                            12mo,  *2 00
+
+Stecher, G. E. Cork. Its Origin and Industrial Uses         12mo,   1 00
+
+Steinman, D. B. Suspension Bridges and Cantilevers.
+  (Science Series No. 127.)                                         0 50
+
+---- Melan's Steel Arches and Suspension Bridges             8vo,  *3 00
+
+Stevens, H. P. Paper Mill Chemist                           16mo,  *2 50
+
+Stevens, J. S. Theory of Measurements                       12mo,  *1 25
+
+Stevenson, J. L. Blast-Furnace Calculations        12mo, leather,  *2 00
+
+Stewart, G. Modern Steam Traps                              12mo,  *1 25
+
+Stiles, A. Tables for Field Engineers                       12mo,   1 00
+
+Stodola, A. Steam Turbines. Trans. by L. C.
+  Loewenstein                                                8vo,  *5 00
+
+Stone, H. The Timbers of Commerce                            8vo,   3 50
+
+Stopes, M. Ancient Plants                                    8vo,  *2 00
+
+---- The Study of Plant Life                                 8vo,  *2 00
+
+Sudborough, J. J., and James, T. C. Practical Organic
+  Chemistry                                                 12mo,  *2 00
+
+Suffling, E. R. Treatise on the Art of Glass Painting        8vo,  *3 50
+
+Sullivan, T. V., and Underwood, N. Testing and
+  Valuation of Building and Engineering Materials          (_In Press._)
+
+Sur, F. J. S. Oil Prospecting and Extracting                 8vo,  *1 00
+
+Svenson, C. L. Handbook on Piping                          (_In Press._)
+
+Swan, K. Patents, Designs and Trade Marks.
+  (Westminster Series.)                                      8vo,  *2 00
+
+Swinburne, J., Wordingham, C. H., and Martin, T. C.
+  Electric Currents. (Science Series No. 109.)              16mo,   0 50
+
+Swoope, C. W. Lessons in Practical Electricity              12mo,  *2 00
+
+
+Tailfer, L. Bleaching Linen and Cotton Yarn and Fabrics      8vo,   6 00
+
+Tate, J. S. Surcharged and Different Forms of
+  Retaining-walls. (Science Series No. 7.)                  16mo,   0 50
+
+Taylor, F. N. Small Water Supplies                          12mo,  *2 50
+
+---- Masonry in Civil Engineering                            8vo,  *2 50
+
+Taylor, T. U. Surveyor's Handbook                  12mo, leather,  *2 00
+
+---- Backbone of Perspective                                12mo,  *1 00
+
+Taylor, W. P. Practical Cement Testing                       8vo,  *3 00
+
+Templeton, W. Practical Mechanic's Workshop
+  Companion                                        12mo, morocco,   2 00
+
+Tenney, E. H. Test Methods for Steam Power Plants.
+  (Van Nostrand's Textbooks.)                               12mo,  *2 50
+
+Terry, H. L. India Rubber and its Manufacture.
+  (Westminster Series.)                                      8vo,  *2 00
+
+Thayer, H. R. Structural Design.                             8vo.
+    Vol. I. Elements of Structural Design                          *2 00
+    Vol. II. Design of Simple Structures                           *4 00
+    Vol. III. Design of Advanced Structures          (_In Preparation._)
+
+---- Foundations and Masonry                         (_In Preparation._)
+
+Thiess, J. B., and Joy, G. A. Toll Telephone Practice        8vo,  *3 50
+
+Thom, C., and Jones, W. H. Telegraphic Connections  oblong, 12mo,   1 50
+
+Thomas, C. W. Paper-makers' Handbook                       (_In Press._)
+
+Thompson, A. B. Oil Fields of Russia                         4to,  *7 50
+
+---- Oil Field Development                                          7 50
+
+Thompson, S. P. Dynamo Electric Machines. (Science
+  Series No. 75.)                                           16mo,   0 50
+
+Thompson, W. P. Handbook of Patent Law of All
+  Countries                                                 16mo,   1 50
+
+Thomson, G. Modern Sanitary Engineering                     12mo,  *3 00
+
+Thomson, G. S. Milk and Cream Testing                       12mo,  *1 75
+
+---- Modern Sanitary Engineering, House Drainage, etc.       8vo,  *3 00
+
+Thornley, T. Cotton Combing Machines                         8vo,  *3 00
+
+---- Cotton Waste                                            8vo,  *3 00
+
+---- Cotton Spinning.                                        8vo.
+    First Year                                                     *1 50
+    Second Year                                                    *3 00
+    Third Year                                                     *2 50
+
+Thurso, J. W. Modern Turbine Practice                        8vo,  *4 00
+
+Tidy, C. Meymott. Treatment of Sewage. (Science Series
+  No. 94.)                                                  16mo,   0 50
+
+Tillmans, J. Water Purification and Sewage Disposal.
+  Trans. by Hugh S. Taylor                                   8vo,  *2 00
+
+Tinney, W. H. Gold-mining Machinery                          8vo,  *3 00
+
+Titherley, A. W. Laboratory Course of Organic Chemistry      8vo,  *2 00
+
+Tizard, H. T. Indicators                                   (_In Press._)
+
+Toch, M. Chemistry and Technology of Paints                  8vo,  *4 00
+
+---- Materials for Permanent Painting                       12mo,  *2 00
+
+Tod, J., and McGibbon, W. C. Marine Engineers' Board
+  of Trade Examinations                                      8vo,  *2 00
+
+Todd, J., and Whall, W. B. Practical Seamanship              8vo,   8 00
+
+Tonge, J. Coal. (Westminster Series.)                        8vo,  *2 00
+
+Townsend, F. Alternating Current Engineering         8vo, boards,  *0 75
+
+Townsend, J. S. Ionization of Gases by Collision             8vo,  *1 25
+
+Transactions of the American Institute of Chemical
+  Engineers, 8vo. Eight volumes now ready. Vol. I.
+  to IX., 1908-1916                                    8vo, each,   6 00
+
+Traverse Tables. (Science Series No. 115.)                  16mo,   0 50
+                                                         morocco,   1 00
+
+Treiber, E. Foundry Machinery. Trans. by C. Salter          12mo,   1 50
+
+Trinks, W., and Housum, C. Shaft Governors. (Science
+  Series No. 122.)                                          16mo,   0 50
+
+Trowbridge, W. P. Turbine Wheels. (Science Series No.
+  44.)                                                      16mo,   0 50
+
+Tucker, J. H. A Manual of Sugar Analysis                     8vo,   3 50
+
+Tunner, P. A. Treatise on Roll-turning. Trans. by
+  J. B. Pearse.                        8vo, text and folio atlas,  10 00
+
+Turnbull, Jr., J., and Robinson, S. W. A Treatise on
+  the Compound Steam-engine. (Science Series No. 8.)        16mo,
+
+Turner, H. Worsted Spinners' Handbook                       12mo,  *2 00
+
+Turrill, S. M. Elementary Course in Perspective             12mo,  *1 25
+
+Twyford, H. B. Purchasing                                    8vo,  *3 00
+
+Tyrrell, H. G. Design and Construction of Mill
+  Buildings                                                  8vo,  *4 00
+
+---- Concrete Bridges and Culverts                 16mo, leather,  *3 00
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+---- Artistic Bridge Design                                  8vo,  *3 00
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+
+Underhill, C. R. Solenoids, Electromagnets and
+  Electromagnetic Windings                                  12mo,  *2 00
+
+Underwood, N., and Sullivan, T. V. Chemistry and
+  Technology of Printing Inks                                8vo,  *3 00
+
+Urquhart, J. W. Electro-plating                             12mo,   2 00
+
+---- Electrotyping                                          12mo,   2 00
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+Usborne, P. O. G. Design of Simple Steel Bridges             8vo,  *4 00
+
+
+Vacher, F. Food Inspector's Handbook                        12mo,
+
+Van Nostrand's Chemical Annual. Third issue 1913   leather, 12mo,  *2 50
+
+---- Year Book of Mechanical Engineering Data              (_In Press._)
+
+Van Wagenen, T. F. Manual of Hydraulic Mining               16mo,   1 00
+
+Vega, Baron Von. Logarithmic Tables                   8vo, cloth,   2 00
+                                                    half morocco,   2 50
+
+Vincent, C. Ammonia and its Compounds. Trans. by
+  M. J. Salter                                               8vo,  *2 00
+
+Volk, C. Haulage and Winding Appliances                      8vo,  *4 00
+
+Von Georgievics, G. Chemical Technology of Textile
+  Fibres. Trans. by C. Salter                                8vo,  *4 50
+
+---- Chemistry of Dyestuffs. Trans. by C. Salter             8vo,  *4 50
+
+Vose, G. L. Graphic Method for Solving Certain
+  Questions in Arithmetic and Algebra (Science
+  Series No. 16.)                                           16mo,   0 50
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+Vosmaer, A. Ozone                                            8vo,  *2 50
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+Wabner, R. Ventilation in Mines. Trans. by C. Salter         8vo,  *4 50
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+Wade, E. J. Secondary Batteries                              8vo,  *4 00
+
+Wadmore, T. M. Elementary Chemical Theory                   12mo,  *1 50
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+Wadsworth, C. Primary Battery Ignition                      12mo,  *0 50
+
+Wagner, E. Preserving Fruits, Vegetables, and Meat          12mo,  *2 50
+
+Wagner, J. B. A Treatise on the Natural and Artificial
+  Processes of Wood Seasoning                         8vo, (_In Press._)
+
+Waldram, P. J. Principles of Structural Mechanics           12mo,  *3 00
+
+Walker, F. Aerial Navigation                                 8vo,   2 00
+
+---- Dynamo Building. (Science Series No. 98.)              16mo,   0 50
+
+Walker, J. Organic Chemistry for Students of Medicine        8vo,  *2 50
+
+Walker, S. F. Steam Boilers, Engines and Turbines            8vo,   3 00
+
+---- Refrigeration, Heating and Ventilation on
+  Shipboard                                                 12mo,  *2 00
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+---- Electricity in Mining                                   8vo,  *3 50
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+Wallis-Tayler, A. J. Bearings and Lubrication                8vo,  *1 50
+
+---- Aerial or Wire Ropeways                                 8vo,  *3 00
+
+---- Sugar Machinery                                        12mo,  *2 00
+
+Walsh, J. J. Chemistry and Physics of Mining and
+  Mine Ventilation,                                         12mo,  *2 00
+
+Wanklyn, J. A. Water Analysis                               12mo,   2 00
+
+Wansbrough, W. D. The A B C of the Differential
+  Calculus                                                  12mo,  *1 50
+
+---- Slide Valves                                           12mo,  *2 00
+
+Waring, Jr., G. E. Sanitary Conditions. (Science
+  Series No. 31.)                                           16mo,   0 50
+
+---- Sewerage and Land Drainage                                    *6 00
+
+---- Modern Methods of Sewage Disposal                      12mo,   2 00
+
+---- How to Drain a House                                   12mo,   1 25
+
+Warnes, A. R. Coal Tar Distillation                          8vo,  *3 00
+
+Warren, F. D. Handbook on Reinforced Concrete               12mo,  *2 50
+
+Watkins, A. Photography. (Westminster Series.)               8vo,  *2 00
+
+Watson, E. P. Small Engines and Boilers                     12mo,   1 25
+
+Watt, A. Electro-plating and Electro-refining of Metals      8vo,  *4 50
+
+---- Electro-metallurgy                                     12mo,   1 00
+
+---- The Art of Soap Making                                  8vo,   3 00
+
+---- Leather Manufacture                                     8vo,  *4 00
+
+---- Paper-Making                                            8vo,   3 00
+
+Webb, H. L. Guide to the Testing of Insulated Wires
+  and Cables                                                12mo,   1 00
+
+Webber, W. H. Y. Town Gas. (Westminster Series.)             8vo,  *2 00
+
+Weisbach, J. A Manual of Theoretical Mechanics               8vo,  *6 00
+                                                           sheep,  *7 50
+
+Weisbach, J., and Herrmann, G. Mechanics of Air
+  Machinery                                                  8vo,  *3 75
+
+Wells, M. B. Steel Bridge Designing                          8vo,  *2 50
+
+Weston, E. B. Loss of Head Due to Friction of Water
+  in Pipes                                                  12mo,  *1 50
+
+Wheatley, O. Ornamental Cement Work                          8vo,  *2 00
+
+Whipple, S. An Elementary and Practical Treatise on
+  Bridge Building                                            8vo,   3 00
+
+White, C. H. Methods of Metallurgical Analysis. (Van
+  Nostrand's Textbooks.)                                    12mo,   2 50
+
+White, G. F. Qualitative Chemical Analysis                  12mo,  *1 25
+
+White, G. T. Toothed Gearing                                12mo,  *1 25
+
+Wilcox, R. M. Cantilever Bridges. (Science Series No. 25.)  16mo,   0 50
+
+Wilda, H. Steam Turbines. Trans. by C. Salter               12mo,   1 50
+
+---- Cranes and Hoists. Trans. by C. Salter                 12mo,   1 50
+
+Wilkinson, H. D. Submarine Cable Laying and Repairing        8vo,  *6 00
+
+Williamson, J. Surveying                                     8vo,  *3 00
+
+Williamson, R. S. On the Use of the Barometer                4to,  15 00
+
+---- Practical Tables in Meteorology and Hypsometry          4to,   2 50
+
+Wilson, F. J., and Heilbron, I. M. Chemical Theory
+  and Calculations                                          12mo,  *1 00
+
+Wilson, J. F. Essentials of Electrical Engineering           8vo,   2 50
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+Wimperis, H. E. Internal Combustion Engine                   8vo,  *3 00
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+---- Application of Power to Road Transport                 12mo,  *1 50
+
+---- Primer of Internal Combustion Engine                   12mo,  *1 00
+
+Winchell, N. H., and A. N. Elements of Optical Mineralogy    8vo,  *3 50
+
+Winslow, A. Stadia Surveying. (Science Series No. 77.)      16mo,   0 50
+
+Wisser, Lieut. J. P. Explosive Materials. (Science
+  Series No. 70.)                                           16mo,   0 50
+
+Wisser, Lieut. J. P. Modern Gun Cotton. (Science
+  Series No. 89.)                                           16mo,   0 50
+
+Wolff, C. E. Modern Locomotive Practice                      8vo,  *4 20
+
+Wood, De V. Luminiferous Aether. (Science Series No. 85)    16mo,   0 50
+
+Wood, J. K. Chemistry of Dyeing. (Chemical Monographs
+  No. 2.)                                                   12mo,  *0 75
+
+Worden, E. C. The Nitrocellulose Industry. Two Volumes       8vo, *10 00
+
+---- Technology of Cellulose Esters. In 10 volumes. 8vo.
+    Vol. VIII. Cellulose Acetate                                   *5 00
+
+Wren, H. Organometallic Compounds of Zinc and Magnesium.
+  (Chemical Monographs No. 1.)                              12mo,  *0 75
+
+Wright, A. C. Analysis of Oils and Allied Substances         8vo,  *3 50
+
+---- Simple Method for Testing Painters' Materials           8vo,  *2 50
+
+Wright, F. W. Design of a Condensing Plant                  12mo,  *1 50
+
+Wright, H. E. Handy Book for Brewers                         8vo,  *5 00
+
+Wright, J. Testing, Fault Finding, etc., for Wiremen.
+  (Installation Manuals Series.)                            16mo,  *0 50
+
+Wright, T. W. Elements of Mechanics                          8vo,  *2 50
+
+Wright, T. W., and Hayford, J. F. Adjustment
+  of Observations                                            8vo,  *3 00
+
+Wynne, W. E., and Sparagen, W. Handbook of Engineering
+  Mathematics                                                8vo,  *2 00
+
+
+Yoder, J. H., and Wharen, G. B. Locomotive Valves
+  and Valve Gears                                            8vo,  *3 00
+
+Young, J. E. Electrical Testing for Telegraph Engineers      8vo,  *4 00
+
+
+Zahner, R. Transmission of Power. (Science Series No. 40.)  16mo,
+
+Zeidler, J., and Lustgarten, J. Electric Arc Lamps           8vo,  *2 00
+
+Zeuner, A. Technical Thermodynamics. Trans. by
+  J. F. Klein. Two Volumes                                   8vo,  *8 00
+
+Zimmer, G. F. Mechanical Handling and Storing
+  of Materials                                               4to, *12 50
+
+Zipser, J. Textile Raw Materials. Trans. by C. Salter        8vo,  *5 00
+
+Zur Nedden, F. Engineering Workshop Machines and
+  Processes. Trans. by J. A. Davenport                       8vo,  *2 00
+
+
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+
+
+page 018--typo fixed: changed 'Oregan' to 'Oregon'
+page 027--fixed: changed 'Michigian' to 'Michigan'
+page 046--typo fixed: changed 'resistence' to 'resistance'
+page 058--typo fixed: changed 'homus' to 'humus'
+page 069--typo fixed: changed 'resistence' to 'resistance'
+page 074--typo fixed: changed 'ilicijolia' to 'ilicifolia'
+page 084--typo fixed: changed 'Novia Scota' to 'Nova Scotia'
+page 086--typo fixed: changed 'visable' to 'visible'
+page 103--typo fixed: changed 'energed' to 'emerged'
+page 106--typo fixed: changed 'absolutley' to 'absolutely'
+page 110--typo fixed: changed 'has' to 'had'
+page 131--typo fixed: changed 'accomodate' to 'accommodate'
+page 163--typo fixed: changed 'hydrodeik' to 'hygrodeik'
+page 181--typo fixed: changed 'longitutudinal' to 'longitudinal'
+page 198--typo fixed: changed 'accomodate' to 'accommodate'
+page 202--typo fixed: changed 'ecomony' to 'economy'
+page 204--typo fixed: changed 'minumim' to 'minimum'
+page 239--typo fixed: changed 'horizonal' to 'horizontal'
+page 257--typo fixed: changed 'arrangment' to 'arrangement'
+page 266--typo fixed: changed 'applicances' to 'appliances'
+page 267--typo fixed: changed 'specialities' to 'specialties'
+page 267--typo fixed: changed 'theary' to 'theory'
+page 274--typo fixed: changed 'Annual of' to 'Annual or'
+
+
+
+
+
+
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+
+The Project Gutenberg EBook of Seasoning of Wood, by Joseph B. Wagner
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Seasoning of Wood
+
+Author: Joseph B. Wagner
+
+Release Date: September 12, 2008 [EBook #26598]
+
+Language: English
+
+Character set encoding: ISO-8859-1
+
+*** START OF THIS PROJECT GUTENBERG EBOOK SEASONING OF WOOD ***
+
+
+
+
+Produced by Jason Isbell, Irma Spehar and the Online
+Distributed Proofreading Team at https://www.pgdp.net
+
+
+
+
+
+
+</pre>
+
+
+<div class="bbox">
+<h1 class="bb">SEASONING OF WOOD</h1>
+
+<p class="subtitle">
+A TREATISE ON THE NATURAL AND ARTIFICIAL
+PROCESSES EMPLOYED IN THE PREPARATION
+OF LUMBER FOR MANUFACTURE,
+WITH DETAILED EXPLANATIONS OF ITS
+USES, CHARACTERISTICS AND PROPERTIES
+</p>
+
+<p class="bb bt center"><i>ILLUSTRATIONS</i></p>
+
+<p class="author"><small>BY</small><br />
+<big>JOSEPH B. WAGNER</big><br />
+
+<small>AUTHOR OF "COOPERAGE"</small></p>
+
+<div class="figcenter" style="width: 100px; padding-top: 1em; padding-bottom: 1em;">
+<img src="images/titlepage.jpg" width="100" height="105" alt="" title="" />
+</div>
+
+<p class="publisher">NEW YORK<br />
+D. VAN NOSTRAND COMPANY<br />
+25 PARK PLACE<br />
+1917</p>
+</div>
+
+<p class="copyright">COPYRIGHT, 1917, BY<br />
+D. VAN NOSTRAND COMPANY<br /><br /><br />
+
+<span style="letter-spacing: 0.25ex">THE&middot;PLIMPTON&middot;PRESS</span><br />
+<span style="letter-spacing: 0.25ex">NORWOOD&middot;MASS&middot;U&middot;S&middot;A</span></p>
+
+
+
+<h3><a name="PREFACE" id="PREFACE"></a>PREFACE<span class='pagenum'><a name="Page_v" id="Page_v">[v]</a></span></h3>
+
+
+<p><span class="smcap">The</span> seasoning and kiln-drying of wood is such an important
+process in the manufacture of woods that a need
+for fuller information regarding it, based upon scientific
+study of the behavior of various species at different mechanical
+temperatures, and under different drying processes
+is keenly felt. Everyone connected with the
+woodworking industry, or its use in manufactured products,
+is well aware of the difficulties encountered in
+properly seasoning or removing the moisture content
+without injury to the timber, and of its susceptibility to
+atmospheric conditions after it has been thoroughly
+seasoned. There is perhaps no material or substance that
+gives up its moisture with more resistance than wood does.
+It vigorously defies the efforts of human ingenuity to take
+away from it, without injury or destruction, that with
+which nature has so generously supplied it.</p>
+
+<p>In the past but little has been known of this matter
+further than the fact that wood contained moisture which
+had to be removed before the wood could be made use of
+for commercial purposes. Within recent years, however,
+considerable interest has been awakened among wood-users
+in the operation of kiln-drying. The losses occasioned
+in air-drying and improper kiln-drying, and the
+necessity for getting the material dry as quickly as possible
+after it has come from the saw, in order to prepare
+it for manufacturing purposes, are bringing about a realization
+of the importance of a technical knowledge of
+the subject.</p>
+
+<p>Since this particular subject has never before been represented
+by any technical work, and appears to have been
+neglected, it is hoped that the trade will appreciate the endeavor
+in bringing this book before them, as well as the
+difficulties encountered in compiling it, as it is the first of<span class='pagenum'><a name="Page_vi" id="Page_vi">[vi]</a></span>
+its kind in existence. The author trusts that his efforts
+will present some information that may be applied with
+advantage, or serve at least as a matter of consideration
+or investigation.</p>
+
+<p>In every case the aim has been to give the facts, and
+wherever a machine or appliance has been illustrated or
+commented upon, or the name of the maker has been
+mentioned, it has not been with the intention either of
+recommending or disparaging his or their work, but has
+been made use of merely to illustrate the text.</p>
+
+<p>The preparation of the following pages has been a work
+of pleasure to the author. If they prove beneficial and
+of service to his fellow-workmen he will have been amply
+repaid.</p>
+
+<p class="right">THE AUTHOR.</p>
+
+<p style="padding-top: 0em; padding-left: 1em">September, 1917</p>
+
+
+
+<h3><a name="CONTENTS" id="CONTENTS"></a>CONTENTS<span class='pagenum'><a name="Page_vii" id="Page_vii">[vii]</a></span></h3>
+
+
+<table summary="table of contents" class="toc">
+
+<tr><td class="tablesec"><a href="#SECTION_I">Section I</a></td><td>&nbsp;</td></tr>
+<tr><td class="chaphead">TIMBER</td><td class="pageno"><small>PAGES</small></td></tr>
+
+<tr><td class="chapentry">Characteristics and Properties of Same&mdash;Structure of Wood&mdash;Properties
+of Wood&mdash;Classes of Trees</td><td class="pageno"><a href="#Page_1">1</a>-<a href="#Page_7">7</a></td></tr>
+
+<tr><td class="tablesec"><a href="#SECTION_II">Section II</a></td><td>&nbsp;</td></tr>
+
+<tr><td class="chaphead">CONIFEROUS TREES</td><td>&nbsp;</td></tr>
+
+<tr><td class="chapentry">Wood of Coniferous Trees&mdash;Bark and Pith&mdash;Sapwood and Heartwood&mdash;The
+Annual or Yearly Ring&mdash;Spring- and Summer-Wood&mdash;Anatomical
+Structure&mdash;List of Important Coniferous Trees</td><td class="pageno"><a href="#Page_8">8</a>-<a href="#Page_30">30</a></td></tr>
+
+<tr><td class="tablesec"><a href="#SECTION_III">Section III</a></td><td>&nbsp;</td></tr>
+
+<tr><td class="chaphead">BROAD-LEAVED TREES</td><td>&nbsp;</td></tr>
+
+<tr><td class="chapentry">Wood of Broad-leaved Trees&mdash;Minute Structure&mdash;List of Most Important
+Broad-leaved Trees&mdash;Red Gum&mdash;Range of Red Gum&mdash;Form
+of Red Gum&mdash;Tolerance of Red Gum&mdash;Its Demands
+upon Soil and Moisture&mdash;Reproduction of Red Gum&mdash;Second-growth
+Red Gum&mdash;Tupelo Gum&mdash;Uses of Tupelo Gum&mdash;Range
+of Tupelo Gum</td><td class="pageno"><a href="#Page_31">31</a>-<a href="#Page_85">85</a></td></tr>
+
+<tr><td class="tablesec"><a href="#SECTION_IV">Section IV</a></td><td>&nbsp;</td></tr>
+
+<tr><td class="chaphead">GRAIN, COLOR, ODOR, WEIGHT, AND FIGURE IN WOOD</td><td>&nbsp;</td></tr>
+
+<tr><td class="chapentry">Different Grains of Wood&mdash;Color and Odor of Wood&mdash;Weight of Wood&mdash;Weight
+of Kiln-dried Wood of Different Species&mdash;Figure in
+Wood</td><td class="pageno"><a href="#Page_86">86</a>-<a href="#Page_97">97</a></td></tr>
+
+<tr><td class="tablesec"><a href="#SECTION_V">Section V</a></td><td>&nbsp;</td></tr>
+
+<tr><td class="chaphead">ENEMIES OF WOOD</td><td>&nbsp;</td></tr>
+
+<tr><td class="chapentry">General Remarks&mdash;Ambrosia or Timber Beetles&mdash;Round-headed
+Borers&mdash;Flat-headed Borers&mdash;Timber Worms&mdash;Powder Post
+Borers&mdash;Conditions Favorable for Insect Injury&mdash;Crude Products&mdash;Round
+Timber with Bark on&mdash;How to Prevent Injury&mdash;Saplings&mdash;Stave,
+Heading, and Shingle Bolts&mdash;Unseasoned
+Products in the Rough&mdash;Seasoned Products in the Rough&mdash;Dry
+Cooperage Stock and Wooden Truss Hoops&mdash;Staves and Heads
+of Barrels Containing Alcoholic Liquids</td><td class="pageno"><a href="#Page_98">98</a>-<a href="#Page_113">113</a><span class='pagenum'><a name="Page_viii" id="Page_viii">[viii]</a></span></td></tr>
+
+<tr><td class="tablesec"><a href="#SECTION_VI">Section VI</a></td><td>&nbsp;</td></tr>
+
+<tr><td class="chaphead">WATER IN WOOD</td><td>&nbsp;</td></tr>
+
+<tr><td class="chapentry">Distribution of Water in Wood&mdash;Seasonal Distribution of Water in
+Wood&mdash;Composition of Sap&mdash;Effects of Moisture on Wood&mdash;The
+Fibre-Saturation Point in Wood</td><td class="pageno"><a href="#Page_114">114</a>-<a href="#Page_118">118</a></td></tr>
+
+
+<tr><td class="tablesec"><a href="#SECTION_VII">Section VII</a></td><td>&nbsp;</td></tr>
+
+<tr><td class="chaphead">WHAT SEASONING IS</td><td>&nbsp;</td></tr>
+
+<tr><td class="chapentry">What Seasoning Is&mdash;Difference Between Seasoned and Unseasoned
+Wood&mdash;Manner of Evaporation of Water&mdash;Absorption of Water
+by Dry Wood&mdash;Rapidity of Evaporation&mdash;Physical Properties
+that Influence Drying</td><td class="pageno"><a href="#Page_119">119</a>-<a href="#Page_127">127</a></td></tr>
+
+
+<tr><td class="tablesec"><a href="#SECTION_VIII">Section VIII</a></td><td>&nbsp;</td></tr>
+
+<tr><td class="chaphead">ADVANTAGES OF SEASONING</td><td>&nbsp;</td></tr>
+
+<tr><td class="chapentry">Advantages of Seasoning&mdash;Prevention of Checking and Splitting&mdash;Shrinkage
+of Wood&mdash;Expansion of Wood&mdash;Elimination of
+Stain and Mildew</td><td class="pageno"><a href="#Page_128">128</a>-<a href="#Page_137">137</a></td></tr>
+
+
+<tr><td class="tablesec"><a href="#SECTION_IX">Section IX</a></td><td>&nbsp;</td></tr>
+
+<tr><td class="chaphead">DIFFICULTIES OF DRYING WOOD</td><td>&nbsp;</td></tr>
+
+<tr><td class="chapentry">Difficulties of Drying Wood&mdash;Changes Rendering Drying Difficult&mdash;Losses
+Due to Improper Kiln-drying&mdash;Properties of Wood that
+Effect Drying&mdash;Unsolved Problems in Kiln-drying</td><td class="pageno"><a href="#Page_138">138</a>-<a href="#Page_144">144</a></td></tr>
+
+
+<tr><td class="tablesec"><a href="#SECTION_X">Section X</a></td><td>&nbsp;</td></tr>
+
+<tr><td class="chaphead">HOW WOOD IS SEASONED</td><td>&nbsp;</td></tr>
+
+<tr><td class="chapentry">Methods of Drying&mdash;Drying at Atmospheric Pressure&mdash;Drying Under
+Pressure and Vacuum&mdash;Impregnation Methods&mdash;Preliminary
+Treatments&mdash;Out-of-door Seasoning</td><td class="pageno"><a href="#Page_145">145</a>-<a href="#Page_155">155</a></td></tr>
+
+
+<tr><td class="tablesec"><a href="#SECTION_XI">Section XI</a></td><td>&nbsp;</td></tr>
+
+<tr><td class="chaphead">KILN-DRYING OF WOOD</td><td>&nbsp;</td></tr>
+
+<tr><td class="chapentry">Advantages of Kiln-drying over Air Drying&mdash;Physical Conditions
+Governing the Drying of Wood&mdash;Theory of Kiln-drying&mdash;Requirements
+in a Satisfactory Dry Kiln&mdash;Kiln-drying&mdash;Remarks&mdash;Underlying
+Principles&mdash;Objects of Kiln-drying&mdash;Conditions
+of Success&mdash;Different Treatments According to Kind&mdash;Temperature
+Depends&mdash;Air Circulation&mdash;Humidity&mdash;Kiln-drying&mdash;Pounds
+of Water Lost in Drying 100 Pounds of Green Wood in the
+Kiln&mdash;Kiln-drying Gum&mdash;Preliminary Steaming&mdash;Final Steaming&mdash;Kiln-drying
+of Green Red Gum</td><td class="pageno"><a href="#Page_156">156</a>-<a href="#Page_184">184</a><span class='pagenum'><a name="Page_ix" id="Page_ix">[ix]</a></span></td></tr>
+
+<tr><td class="tablesec"><a href="#SECTION_XII">Section XII</a></td><td>&nbsp;</td></tr>
+
+<tr><td class="chaphead">TYPES OF DRY KILNS</td><td>&nbsp;</td></tr>
+
+<tr><td class="chapentry">Different types of Dry Kilns&mdash;The "Blower" or "Hot Blast" Dry
+Kiln&mdash;Operating the "Blower" or "Hot Blast" Dry Kiln&mdash;The
+"Pipe" or "Moist-Air" Dry Kiln&mdash;Operating the "Pipe" or
+"Moist-Air" Dry Kiln&mdash;Choice of Drying Method&mdash;Kilns of
+Different Types&mdash;The "Progressive" Dry Kiln&mdash;The "Apartment"
+Dry Kiln&mdash;The "Pocket" Dry Kiln&mdash;The "Tower"
+Dry Kiln&mdash;The "Box" Dry Kiln</td><td class="pageno"><a href="#Page_185">185</a>-<a href="#Page_205">205</a></td></tr>
+
+
+<tr><td class="tablesec"><a href="#SECTION_XIII">Section XIII</a></td><td>&nbsp;</td></tr>
+
+<tr><td class="chaphead">DRY KILN SPECIALTIES</td><td>&nbsp;</td></tr>
+
+<tr><td class="chapentry">Kiln Cars and Method of Loading Same&mdash;The "Cross-wise" Piling
+Method&mdash;The "End-wise" Piling Method&mdash;The "Edge-wise"
+Piling Method&mdash;The Automatic Lumber Stacker&mdash;The Unstacker
+Car&mdash;Stave Piling&mdash;Shingle Piling&mdash;Stave Bolt Trucks&mdash;Different
+Types of Kiln Cars&mdash;Different Types of Transfer
+Cars&mdash;Dry Kiln Doors&mdash;Different Types of Kiln Door Carriers</td><td class="pageno"><a href="#Page_206">206</a>-<a href="#Page_236">236</a></td></tr>
+
+
+<tr><td class="tablesec"><a href="#SECTION_XIV">Section XIV</a></td><td>&nbsp;</td></tr>
+
+<tr><td class="chaphead">HELPFUL APPLIANCES IN KILN DRYING</td><td>&nbsp;</td></tr>
+
+<tr><td class="chapentry">The Humidity Diagram&mdash;Examples of Use&mdash;The Hygrodeik&mdash;The
+Recording Hygrometer&mdash;The Registering Hygrometer&mdash;The
+Recording Thermometer&mdash;The Registering Thermometer&mdash;The
+Recording Steam Gauge&mdash;The Troemroid Scalometer&mdash;Test
+Samples&mdash;Weighing&mdash;Examples of Use&mdash;Records of Moisture
+Content&mdash;Saw Mills&mdash;Factories&mdash;The Electric Heater</td><td class="pageno"><a href="#Page_237">237</a>-<a href="#Page_250">250</a></td></tr>
+
+
+<tr><td class="tablesec"><a href="#BIBLIOGRAPHY">Section XV</a></td><td>&nbsp;</td></tr>
+
+<tr><td class="chapentry">Bibliography&mdash;Glossary&mdash;Index of Latin Names&mdash;Index of Common
+Names</td><td class="pageno"><a href="#Page_251">251</a>-<a href="#Page_257">257</a><span class='pagenum'><a name="Page_x" id="Page_x">[x]</a></span></td></tr>
+</table>
+
+
+<h3><a name="LIST_OF_ILLUSTRATIONS" id="LIST_OF_ILLUSTRATIONS"></a>LIST OF ILLUSTRATIONS<span class='pagenum'><a name="Page_xi" id="Page_xi">[xi]</a></span></h3>
+
+<table summary="list of illustrations" class="toc">
+<tr><td class="illono"><small>FIG.</small></td><td>&nbsp;</td><td class="pageno"><small>PAGE</small></td></tr>
+
+<tr><td class="illono">1.</td><td class="illoentry"><a href="#Fig_1">Board of pine</a></td><td class="pageno">13</td></tr>
+<tr><td class="illono">2.</td><td class="illoentry"><a href="#Fig_2">Wood of spruce</a></td><td class="pageno">14</td></tr>
+<tr><td class="illono">3.</td><td class="illoentry"><a href="#Fig_3">Group of fibres from pine wood</a></td><td class="pageno">15</td></tr>
+<tr><td class="illono">4.</td><td class="illoentry"><a href="#Fig_4">Block of oak</a></td><td class="pageno">31</td></tr>
+<tr><td class="illono">5.</td><td class="illoentry"><a href="#Fig_5">Board of oak</a></td><td class="pageno">32</td></tr>
+<tr><td class="illono">6.</td><td class="illoentry"><a href="#Fig_6">Cross-section of oak highly magnified</a></td><td class="pageno">32</td></tr>
+<tr><td class="illono">7.</td><td class="illoentry"><a href="#Fig_7">Highly magnified fibres of wood</a></td><td class="pageno">33</td></tr>
+<tr><td class="illono">8.</td><td class="illoentry"><a href="#Fig_8">Isolated fibres and cells of wood</a></td><td class="pageno">34</td></tr>
+<tr><td class="illono">9.</td><td class="illoentry"><a href="#Fig_9">Cross-section of basswood</a></td><td class="pageno">35</td></tr>
+<tr><td class="illono">10.</td><td class="illoentry"><a href="#Fig_10">A large red gum</a></td><td class="pageno">52</td></tr>
+<tr><td class="illono">11.</td><td class="illoentry"><a href="#Fig_11">A tupelo gum slough</a></td><td class="pageno">53</td></tr>
+<tr><td class="illono">12.</td><td class="illoentry"><a href="#Fig_12">Second growth red gum</a></td><td class="pageno">57</td></tr>
+<tr><td class="illono">13.</td><td class="illoentry"><a href="#Fig_13">A cypress slough in dry season</a></td><td class="pageno">58</td></tr>
+<tr><td class="illono">14.</td><td class="illoentry"><a href="#Fig_14">A large cottonwood</a></td><td class="pageno">78</td></tr>
+<tr><td class="illono">15.</td><td class="illoentry"><a href="#Fig_15">Spiral grain in wood</a></td><td class="pageno">87</td></tr>
+<tr><td class="illono">16.</td><td class="illoentry"><a href="#Fig_16">Alternating spiral grain in cypress</a></td><td class="pageno">87</td></tr>
+<tr><td class="illono">17.</td><td class="illoentry"><a href="#Fig_17">Wavy grain in beech</a></td><td class="pageno">88</td></tr>
+<tr><td class="illono">18.</td><td class="illoentry"><a href="#Fig_18">Section of wood showing position of the grain at base of limb</a></td><td class="pageno">89</td></tr>
+<tr><td class="illono">19.</td><td class="illoentry"><a href="#Fig_19">Cross-section of a group of wood fibres</a></td><td class="pageno">91</td></tr>
+<tr><td class="illono">20.</td><td class="illoentry"><a href="#Fig_20">Isolated fibres of wood</a></td><td class="pageno">91</td></tr>
+<tr><td class="illono">21.</td><td class="illoentry"><a href="#Fig_21">Orientation of wood samples</a></td><td class="pageno">93</td></tr>
+<tr><td class="illono">22.</td><td class="illoentry"><a href="#Fig_22">Work of ambrosia beetles in tulip or yellow poplar</a></td><td class="pageno">100</td></tr>
+<tr><td class="illono">23.</td><td class="illoentry"><a href="#Fig_23">Work of ambrosia beetles in oak</a></td><td class="pageno">100</td></tr>
+<tr><td class="illono">24.</td><td class="illoentry"><a href="#Fig_24">Work of round-headed and flat-headed borers in pine</a></td><td class="pageno">102</td></tr>
+<tr><td class="illono">25.</td><td class="illoentry"><a href="#Fig_25">Work of timber worms in oak</a></td><td class="pageno">103</td></tr>
+<tr><td class="illono">26.</td><td class="illoentry"><a href="#Fig_26">Work of powder post borers in hickory poles</a></td><td class="pageno">104</td></tr>
+<tr><td class="illono">27.</td><td class="illoentry"><a href="#Fig_27">Work of powder post borers in hickory poles</a></td><td class="pageno">104</td></tr>
+<tr><td class="illono">28.</td><td class="illoentry"><a href="#Fig_28">Work of powder post borers in hickory handles</a></td><td class="pageno">105</td></tr>
+<tr><td class="illono">29.</td><td class="illoentry"><a href="#Fig_29">Work of round-headed borers in white pine staves</a></td><td class="pageno">111</td></tr>
+<tr><td class="illono">30.</td><td class="illoentry"><a href="#Fig_30">U.&nbsp;S. Forest Service humidity controlled dry kiln</a></td><td class="pageno">161</td></tr>
+<tr><td class="illono">31.</td><td class="illoentry"><a href="#Fig_31">Section through moist-air dry kiln</a></td><td class="pageno">189</td></tr>
+<tr><td class="illono">32.</td><td class="illoentry"><a href="#Fig_32">Live steam single pipe heating apparatus</a></td><td class="pageno">190</td></tr>
+<tr><td class="illono">33.</td><td class="illoentry"><a href="#Fig_33">Live steam double pipe heating apparatus</a></td><td class="pageno">191</td></tr>
+<tr><td class="illono">34.</td><td class="illoentry"><a href="#Fig_34">Vertical Pipe heating apparatus</a></td><td class="pageno">193</td></tr>
+<tr><td class="illono">35.</td><td class="illoentry"><a href="#Fig_35">Progressive dry kilns</a></td><td class="pageno">197</td></tr>
+<tr><td class="illono">36.</td><td class="illoentry"><a href="#Fig_36">Apartment dry kilns</a></td><td class="pageno">199</td></tr>
+<tr><td class="illono">37.</td><td class="illoentry"><a href="#Fig_37">Pocket dry kilns</a></td><td class="pageno">201</td></tr>
+<tr><td class="illono">38.</td><td class="illoentry"><a href="#Fig_38">Tower dry kiln</a></td><td class="pageno">203</td></tr>
+<tr><td class="illono">39.</td><td class="illoentry"><a href="#Fig_39">Box dry kiln</a></td><td class="pageno">205</td></tr>
+<tr><td class="illono">40.</td><td class="illoentry"><a href="#Fig_40">Edge-wise method of piling</a></td><td class="pageno">206<span class='pagenum'><a name="Page_xii" id="Page_xii">[xii]</a></span></td></tr>
+<tr><td class="illono">41.</td><td class="illoentry"><a href="#Fig_41">Edge-wise method of piling</a></td><td class="pageno">207</td></tr>
+<tr><td class="illono">42.</td><td class="illoentry"><a href="#Fig_42">Automatic lumber stacker</a></td><td class="pageno">208</td></tr>
+<tr><td class="illono">43.</td><td class="illoentry"><a href="#Fig_43">Automatic lumber stacker</a></td><td class="pageno">208</td></tr>
+<tr><td class="illono">44.</td><td class="illoentry"><a href="#Fig_44">Battery of three automatic lumber stackers</a></td><td class="pageno">209</td></tr>
+<tr><td class="illono">45.</td><td class="illoentry"><a href="#Fig_45">Battery of three automatic lumber stackers</a></td><td class="pageno">209</td></tr>
+<tr><td class="illono">46.</td><td class="illoentry"><a href="#Fig_46">Lumber loaded edge-wise on kiln truck</a></td><td class="pageno">210</td></tr>
+<tr><td class="illono">47.</td><td class="illoentry"><a href="#Fig_47">The lumber unstacker</a></td><td class="pageno">211</td></tr>
+<tr><td class="illono">48.</td><td class="illoentry"><a href="#Fig_48">The lumber unstacker car</a></td><td class="pageno">211</td></tr>
+<tr><td class="illono">49.</td><td class="illoentry"><a href="#Fig_49">Method of piling veneer on edge</a></td><td class="pageno">212</td></tr>
+<tr><td class="illono">50.</td><td class="illoentry"><a href="#Fig_50">Kiln truck loaded cross-wise of kiln</a></td><td class="pageno">213</td></tr>
+<tr><td class="illono">51.</td><td class="illoentry"><a href="#Fig_51">Kiln truck loaded cross-wise of kiln</a></td><td class="pageno">214</td></tr>
+<tr><td class="illono">52.</td><td class="illoentry"><a href="#Fig_52">Kiln truck loaded end-wise of kiln</a></td><td class="pageno">214</td></tr>
+<tr><td class="illono">53.</td><td class="illoentry"><a href="#Fig_53">Kiln truck loaded end-wise of kiln</a></td><td class="pageno">215</td></tr>
+<tr><td class="illono">54.</td><td class="illoentry"><a href="#Fig_54">Method of piling staves on kiln truck</a></td><td class="pageno">216</td></tr>
+<tr><td class="illono">55.</td><td class="illoentry"><a href="#Fig_55">Method of piling staves on kiln truck</a></td><td class="pageno">216</td></tr>
+<tr><td class="illono">56.</td><td class="illoentry"><a href="#Fig_56">Method of piling tub or pail staves on kiln truck</a></td><td class="pageno">217</td></tr>
+<tr><td class="illono">57.</td><td class="illoentry"><a href="#Fig_57">Method of piling bundled staves on kiln truck</a></td><td class="pageno">217</td></tr>
+<tr><td class="illono">58.</td><td class="illoentry"><a href="#Fig_58">Method of piling shingles on kiln truck</a></td><td class="pageno">218</td></tr>
+<tr><td class="illono">59.</td><td class="illoentry"><a href="#Fig_59">Method of piling shingles on kiln truck</a></td><td class="pageno">218</td></tr>
+<tr><td class="illono">60.</td><td class="illoentry"><a href="#Fig_60">Method of piling shingles on kiln truck</a></td><td class="pageno">219</td></tr>
+<tr><td class="illono">61.</td><td class="illoentry"><a href="#Fig_61">Kiln truck designed for loose pail staves</a></td><td class="pageno">219</td></tr>
+<tr><td class="illono">62.</td><td class="illoentry"><a href="#Fig_62">Kiln truck designed for handling short stock</a></td><td class="pageno">221</td></tr>
+<tr><td class="illono">63.</td><td class="illoentry"><a href="#Fig_63">Stave bolt truck</a></td><td class="pageno">221</td></tr>
+<tr><td class="illono">64.</td><td class="illoentry"><a href="#Fig_64">Stave bolt truck</a></td><td class="pageno">222</td></tr>
+<tr><td class="illono">65.</td><td class="illoentry"><a href="#Fig_65">Stave bolt truck</a></td><td class="pageno">222</td></tr>
+<tr><td class="illono">66.</td><td class="illoentry"><a href="#Fig_66">Stave bolt truck</a></td><td class="pageno">223</td></tr>
+<tr><td class="illono">67.</td><td class="illoentry"><a href="#Fig_67">Stave bolt truck</a></td><td class="pageno">223</td></tr>
+<tr><td class="illono">68.</td><td class="illoentry"><a href="#Fig_68">Stave bolt truck</a></td><td class="pageno">224</td></tr>
+<tr><td class="illono">69.</td><td class="illoentry"><a href="#Fig_69">Regular 3-rail transfer car</a></td><td class="pageno">224</td></tr>
+<tr><td class="illono">70.</td><td class="illoentry"><a href="#Fig_70">Regular 3-rail transfer car</a></td><td class="pageno">225</td></tr>
+<tr><td class="illono">71.</td><td class="illoentry"><a href="#Fig_71">Special 4-rail transfer car</a></td><td class="pageno">225</td></tr>
+<tr><td class="illono">72.</td><td class="illoentry"><a href="#Fig_72">Regular 2-rail transfer car</a></td><td class="pageno">225</td></tr>
+<tr><td class="illono">73.</td><td class="illoentry"><a href="#Fig_73">Regular 2-rail transfer car</a></td><td class="pageno"> 226</td></tr>
+<tr><td class="illono">74.</td><td class="illoentry"><a href="#Fig_74">Underslung type 3-rail transfer car</a></td><td class="pageno">226</td></tr>
+<tr><td class="illono">75.</td><td class="illoentry"><a href="#Fig_75">Underslung type 2-rail transfer car</a></td><td class="pageno">226</td></tr>
+<tr><td class="illono">76.</td><td class="illoentry"><a href="#Fig_76">Flexible type 2-rail transfer car</a></td><td class="pageno">227</td></tr>
+<tr><td class="illono">77.</td><td class="illoentry"><a href="#Fig_77">Regular transfer car for stave bolt trucks</a></td><td class="pageno">228</td></tr>
+<tr><td class="illono">78.</td><td class="illoentry"><a href="#Fig_78">Regular transfer car for stave bolt trucks</a></td><td class="pageno">228</td></tr>
+<tr><td class="illono">79.</td><td class="illoentry"><a href="#Fig_79">Special transfer car for stave bolt trucks</a></td><td class="pageno">228</td></tr>
+<tr><td class="illono">80.</td><td class="illoentry"><a href="#Fig_80">Regular channel iron kiln truck for cross-wise piling</a></td><td class="pageno">229</td></tr>
+<tr><td class="illono">81.</td><td class="illoentry"><a href="#Fig_81">Regular channel iron kiln truck for cross-wise piling</a></td><td class="pageno">229</td></tr>
+<tr><td class="illono">82.</td><td class="illoentry"><a href="#Fig_82">Regular channel iron kiln truck for end-wise piling</a></td><td class="pageno">230</td></tr>
+<tr><td class="illono">83.</td><td class="illoentry"><a href="#Fig_82">Special channel iron kiln truck for end-wise piling</a></td><td class="pageno">230</td></tr>
+<tr><td class="illono">84.</td><td class="illoentry"><a href="#Fig_84">Regular dolly kiln truck for end-wise piling</a></td><td class="pageno">230</td></tr>
+<tr><td class="illono">85.</td><td class="illoentry"><a href="#Fig_85">Asbestos-lined kiln door</a></td><td class="pageno">231</td></tr>
+<tr><td class="illono">86.</td><td class="illoentry"><a href="#Fig_86">Twin door carrier with door loaded</a></td><td class="pageno">232</td></tr>
+<tr><td class="illono">87.</td><td class="illoentry"><a href="#Fig_87">Twin door carrier for doors 18 to 35 feet wide</a></td><td class="pageno">232</td></tr>
+<tr><td class="illono">88.</td><td class="illoentry"><a href="#Fig_88">Kiln door carrier</a></td><td class="pageno">233</td></tr>
+<tr><td class="illono">89.</td><td class="illoentry"><a href="#Fig_89">Kiln door construction</a></td><td class="pageno">234</td></tr>
+<tr><td class="illono">90.</td><td class="illoentry"><a href="#Fig_90">Kiln door construction</a></td><td class="pageno">235</td></tr>
+<tr><td class="illono">91.</td><td class="illoentry"><a href="#Fig_91">Kiln door construction</a></td><td class="pageno">235</td></tr>
+<tr><td class="illono">92.</td><td class="illoentry"><a href="#Fig_92">Kiln door construction</a></td><td class="pageno">236<span class='pagenum'><a name="Page_xiii" id="Page_xiii">[xiii]</a></span></td></tr>
+<tr><td class="illono">93.</td><td class="illoentry"><a href="#Fig_93">The Humidity diagram</a></td><td class="pageno"><i>facing</i>   237</td></tr>
+<tr><td class="illono">94.</td><td class="illoentry"><a href="#Fig_94">The hygrodeik</a></td><td class="pageno">242</td></tr>
+<tr><td class="illono">95.</td><td class="illoentry"><a href="#Fig_95">The recording hygrometer</a></td><td class="pageno">243</td></tr>
+<tr><td class="illono">96.</td><td class="illoentry"><a href="#Fig_96">The registering hygrometer</a></td><td class="pageno">244</td></tr>
+<tr><td class="illono">97.</td><td class="illoentry"><a href="#Fig_97">The recording thermometer</a></td><td class="pageno">245</td></tr>
+<tr><td class="illono">98.</td><td class="illoentry"><a href="#Fig_98">The registering thermometer</a></td><td class="pageno">246</td></tr>
+<tr><td class="illono">99.</td><td class="illoentry"><a href="#Fig_99">The recording steam gauge</a></td><td class="pageno">246</td></tr>
+<tr><td class="illono">100.</td><td class="illoentry"><a href="#Fig_100">The troemroid scalometer</a></td><td class="pageno">247</td></tr>
+<tr><td class="illono">101.</td><td class="illoentry"><a href="#Fig_101">The electric heater</a></td><td class="pageno">250</td></tr>
+</table>
+
+
+
+<h2 style="padding-top: 2em"><a name="SEASONING_OF_WOOD" id="SEASONING_OF_WOOD"></a>SEASONING OF WOOD<span class='pagenum'><a name="Page_1" id="Page_1">[1]</a></span></h2>
+
+
+
+<h3 style="padding-bottom: 0em"><a name="SECTION_I" id="SECTION_I"></a>SECTION I</h3>
+
+<h2>TIMBER</h2>
+
+<h4>Characteristics and Properties</h4>
+
+
+<p><span class="smcap">Timber</span> was probably one of the earliest, if not the
+earliest, of materials used by man for constructional purposes.
+With it he built for himself a shelter from the
+elements; it provided him with fuel and oft-times food,
+and the tree cut down and let across a stream formed the
+first bridge. From it, too, he made his "dug-out" to
+travel along and across the rivers of the district in which
+he dwelt; so on down through the ages, for shipbuilding
+and constructive purposes, timber has continued to our
+own time to be one of the most largely used of nature's
+products.</p>
+
+<p>Although wood has been in use so long and so universally,
+there still exists a remarkable lack of knowledge regarding
+its nature, not only among ordinary workmen, but
+among those who might be expected to know its properties.
+Consequently it is often used in a faulty and wasteful
+manner. Experience has been almost the only teacher,
+and theories&mdash;sometimes right, sometimes wrong&mdash;rather
+than well substantiated facts, lead the workman.</p>
+
+<p>One reason for this imperfect knowledge lies in the fact
+that wood is not a homogeneous material, but a complicated
+structure, and so variable, that one piece will behave
+very differently from another, although cut from the same
+tree. Not only does the wood of one species differ from
+that of another, but the butt cut differs from that of the
+top log, the heartwood from the sapwood; the wood of
+quickly-grown sapling of the abandoned field, from<span class='pagenum'><a name="Page_2" id="Page_2">[2]</a></span>
+that of the slowly-grown, old monarch of the forest. Even
+the manner in which the tree was cut and kept influences
+its behavior and quality. It is therefore extremely difficult
+to study the material for the purpose of establishing
+general laws.</p>
+
+<p>The experienced woodsman will look for straight-grained,
+long-fibred woods, with the absence of disturbing
+resinous and coloring matter, knots, etc., and will
+quickly distinguish the more porous red or black oaks from
+the less porous white species, <i>Quercus alba</i>. That the
+inspection should have regard to defects and unhealthy
+conditions (often indicated by color) goes without saying,
+and such inspection is usually practised. That knots,
+even the smallest, are defects, which for some uses condemn
+the material entirely, need hardly be mentioned.
+But that "season-checks," even those that have closed
+by subsequent shrinkage, remain elements of weakness
+is not so readily appreciated; yet there cannot be any
+doubt of this, since these, the intimate connections of
+the wood fibres, when once interrupted are never reestablished.</p>
+
+<p>Careful woods-foremen and manufacturers, therefore,
+are concerned as to the manner in which their timber is
+treated after the felling, for, according to the more or less
+careful seasoning of it, the season checks&mdash;not altogether
+avoidable&mdash;are more or less abundant.</p>
+
+<p>There is no country where wood is more lavishly used
+or criminally neglected than in the United States, and
+none in which nature has more bountifully provided for
+all reasonable requirements.</p>
+
+<p>In the absence of proper efforts to secure reproduction,
+the most valuable kinds are rapidly being decimated, and
+the necessity of a more rational and careful use of what
+remains is clearly apparent. By greater care in selection,
+however, not only will the duration of the supply be extended,
+but more satisfactory results will accrue from its
+practice.</p>
+
+<p>There are few more extensive and wide-reaching subjects
+on which to treat than timber, which in this book
+refers to dead timber&mdash;the timber of commerce&mdash;as<span class='pagenum'><a name="Page_3" id="Page_3">[3]</a></span>
+distinct from the living tree. Such a great number of
+different kinds of wood are now being brought from various
+parts of the world, so many new kinds are continually
+being added, and the subject is more difficult to explain
+because timber of practically the same character which
+comes from different localities goes under different names,
+that if one were always to adhere to the botanical name
+there would be less confusion, although even botanists
+differ in some cases as to names. Except in the cases of
+the older and better known timbers, one rarely takes up
+two books dealing with timber and finds the botanical
+names the same; moreover, trees of the same species may
+produce a much poorer quality of timber when obtained
+from different localities in the same country, so that botanical
+knowledge will not always allow us to dispense with
+other tests.</p>
+
+<p>The structure of wood affords the only reliable means
+of distinguishing the different kinds. Color, weight, smell,
+and other appearances, which are often direct or indirect
+results of structure, may be helpful in this distinction,
+but cannot be relied upon entirely. Furthermore, structure
+underlies nearly all the technical properties of this
+important product, and furnishes an explanation why one
+piece differs in these properties from another. Structure
+explains why oak is heavier, stronger, and tougher than
+pine; why it is harder to saw and plane, and why it is so
+much more difficult to season without injury. From its
+less porous structure alone it is evident that a piece of
+young and thrifty oak is stronger than the porous wood
+of an old or stunted tree, or that a Georgia or long-leaf
+pine excels white pine in weight and strength.</p>
+
+<p>Keeping especially in mind the arrangement and direction
+of the fibres of wood, it is clear at once why knots and
+"cross-grain" interfere with the strength of timber. It
+is due to the structural peculiarities that "honeycombing"
+occurs in rapid seasoning, that checks or cracks extend
+radially and follow pith rays, that tangent or "bastard"
+cut stock shrinks and warps more than that which is
+quarter-sawn. These same peculiarities enable oak to
+take a better finish than basswood or coarse-grained pine.<span class='pagenum'><a name="Page_4" id="Page_4">[4]</a></span></p>
+
+
+<h4>Structure of Wood</h4>
+
+<p>The softwoods are made up chiefly of tracheids, or
+vertical cells closed at the ends, and of the relatively short
+parenchyma cells of the medullary rays which extend
+radially from the heart of the tree. The course of the
+tracheids and the rays are at right angles to each other.
+Although the tracheids have their permeable portions or
+pits in their walls, liquids cannot pass through them with
+the greatest ease. The softwoods do not contain "pores"
+or vessels and are therefore called "non-porous" woods.</p>
+
+<p>The hardwoods are not so simple in structure as softwoods.
+They contain not only rays, and in many cases
+tracheids, but also thick-walled cells called fibres and wood
+parenchyma for the storage of such foods as starches and
+sugars. The principal structural features of the hardwoods
+are the pores or vessels. These are long tubes, the
+segments of which are made up of cells which have lost
+their end walls and joined end to end, forming continuous
+"pipe lines" from the roots to the leaves in the tree. Since
+they possess pores or vessels, the hardwoods are called
+"porous" woods.</p>
+
+<p>Red oak is an excellent example of a porous wood. In
+white oak the vessels of the heartwood especially are
+closed, very generally by ingrowths called tyloses. This
+probably explains why red oak dries more easily and
+rapidly than white oak.</p>
+
+<p>The red and black gums are perhaps the simplest of the
+hardwoods in structure. They are termed "diffuse porous"
+woods because of the numerous scattered pores
+they contain. They have only vessels, wood fibres, and
+a few parenchyma cells. The medullary rays, although
+present, are scarcely visible in most instances. The
+vessels are in many cases open, and might be expected to
+offer relatively little resistance to drying.</p>
+
+
+<h4>Properties of Wood</h4>
+
+<p>Certain general properties of wood may be discussed
+briefly. We know that wood substance has the property
+of taking in moisture from the air until some balance is<span class='pagenum'><a name="Page_5" id="Page_5">[5]</a></span>
+reached between the humidity of the air and the moisture
+in the wood. This moisture which goes into the cell walls
+hygroscopic moisture, and the property which the wood
+substance has of taking on hygroscopic moisture is termed
+hygroscopicity. Usually wood contains not only hygroscopic
+moisture but also more or less free water in the
+cell cavities. Especially is this true of sapwood. The
+free water usually dries out quite rapidly with little or no
+shrinkage or other physical change.</p>
+
+<p>In certain woods&mdash;for example, <i>Eucalyptus globulus</i> and
+possibly some oaks&mdash;shrinkage begins almost at once, thus
+introducing a factor at the very start of the seasoning process
+which makes these woods very refractory.</p>
+
+<p>The cell walls of some species, including the two already
+mentioned, such as Western red cedar and redwood, become
+soft and plastic when hot and moist. If the fibres
+are hot enough and very wet, they are not strong enough
+to withstand the resulting force of the atmospheric pressure
+and the tensile force exerted by the departing free
+water, and the result is that the cells actually collapse.</p>
+
+<p>In general, however, the hygroscopic moisture necessary
+to saturate the cell walls is termed the "fibre saturation
+point." This amount has been found to be from
+25 to 30 per cent of the dry wood weight. Unlike <i>Eucalyptus
+globulus</i> and certain oaks, the gums do not begin
+to shrink until the moisture content has been reduced to
+about 30 per cent of the dry wood weight. These woods
+are not subject to collapse, although their fibres become
+very plastic while hot and moist.</p>
+
+<p>Upon the peculiar properties of each wood depends the
+difficulty or ease of the seasoning process.</p>
+
+
+<h4>Classes of Trees</h4>
+
+<p>The timber of the United States is furnished by three
+well-defined classes of trees: (1) The needle-leaved, naked-seeded
+conifers, such as pine, cedar, etc., (2) the broad-leaved
+trees such as oak poplar, etc., and (3) to an
+inferior extent by the (one-seed leaf) palms, yuccas,
+and their allies, which are confined to the most southern
+parts of the country.<span class='pagenum'><a name="Page_6" id="Page_6">[6]</a></span></p>
+
+<p>Broad-leaved trees are also known as deciduous trees,
+although, especially in warm countries, many of them are
+evergreen, while the needle-leaved trees (conifers) are
+commonly termed "evergreens," although the larch, bald
+cypress, and others shed their leaves every fall, and even
+the names "broad-leaved" and "coniferous," though perhaps
+the most satisfactory, are not at all exact, for the
+conifer "ginkgo" has broad leaves and bears no cones.</p>
+
+<p>Among the woodsmen, the woods of broad-leaved trees
+are known as "hardwoods," though poplar is as soft as
+pine, and the "coniferous woods" are known as "softwoods,"
+notwithstanding the fact that yew ranks high in
+hardness even when compared with "hardwoods."</p>
+
+<p>Both in the number of different kinds of trees or species
+and still more in the importance of their product, the conifers
+and broad-leaved trees far excel the palms and their
+relatives.</p>
+
+<p>In the manner of their growth both the conifers and
+broad-leaved trees behave alike, adding each year a new
+layer of wood, which covers the old wood in all parts of
+the stem and limbs. Thus the trunk continues to grow
+in thickness throughout the life of the tree by additions
+(annual rings), which in temperate climates are, barring
+accidents, accurate records of the tree. With the palms
+and their relatives the stem remains generally of the same
+diameter, the tree of a hundred years old being as thick
+as it was at ten years, the growth of these being only at
+the top. Even where a peripheral increase takes place,
+as in the yuccas, the wood is not laid on in well-defined
+layers for the structure remains irregular throughout.
+Though alike in the manner of their growth, and therefore
+similar in their general make-up, conifers and broad-leaved
+trees differ markedly in the details of their structure and
+the character of their wood.</p>
+
+<p>The wood of all conifers is very simple in its structure,
+the fibres composing the main part of the wood all being
+alike and their arrangement regular. The wood of the
+broad-leaved trees is complex in structure; it is made up
+of different kinds of cells and fibres and lacks the regularity
+of arrangement so noticeable in the conifers. This<span class='pagenum'><a name="Page_7" id="Page_7">[7]</a></span>
+difference is so great that in a study of wood structure it
+is best to consider the two kinds separately.</p>
+
+<p>In this country the great variety of woods, and especially
+of useful woods, often makes the mere distinction of the
+kind or species of tree most difficult. Thus there are at
+least eight pines of the thirty-five native ones in the market,
+some of which so closely resemble each other in their
+minute structure that one can hardly tell them apart, and
+yet they differ in quality and are often mixed or confounded
+in the trade. Of the thirty-six oaks, of which
+probably not less than six or eight are marketed, we can
+readily recognize by means of their minute anatomy at
+least two tribes&mdash;the white and black oaks. The same
+is true of the eleven kinds of hickory, the six kinds of ash,
+etc., etc.</p>
+
+<p>The list of names of all trees indigenous to the United
+States, as enumerated by the United States Forest Service,
+is 495 in number, the designation of "tree" being applied
+to all woody plants which produce naturally in their
+native habitat one main, erect stem, bearing a definite
+crown, no matter what size they attain.</p>
+
+<p>Timber is produced only by the Spermatophyta, or
+seed-bearing plants, which are subdivided into the Gymnosperms
+(conifers), and Angiosperms (broad-leaved).
+The conifer or cone-bearing tree, to which belong the pines,
+larches, and firs, is one of the three natural orders of Gymnosperms.
+These are generally classed as "softwoods,"
+and are more extensively scattered and more generally
+used than any other class of timber, and are simple and
+regular in structure. The so-called "hardwoods" are
+"Dicotyledons" or broad-leaved trees, a subdivision of
+the Angiosperms. They are generally of slower growth,
+and produce harder timber than the conifers, but not
+necessarily so. Basswood, poplar, sycamore, and some
+of the gums, though classed with the hardwoods, are not
+nearly as hard as some of the pines.</p>
+
+
+
+<h3 style="padding-bottom: 0em"><a name="SECTION_II" id="SECTION_II"></a>SECTION II<span class='pagenum'><a name="Page_8" id="Page_8">[8]</a></span></h3>
+
+<h2>CONIFEROUS TREES</h2>
+
+<h3 style="padding-top: 0em">WOOD OF THE CONIFEROUS TREES</h3>
+
+
+<p><span class="smcap">Examining</span> a smooth cross-section or end face of a well-grown
+log of Georgia pine, we distinguish an envelope of
+reddish, scaly bark, a small, whitish pith at the center,
+and between these the wood in a great number of concentric
+rings.</p>
+
+
+<h4>Bark and Pith</h4>
+
+<p>The bark of a pine stem is thickest and roughest near
+the base, decreases rapidly in thickness from one to one-half
+inches at the stump to one-tenth inch near the top
+of the tree, and forms in general about ten to fifteen per
+cent of the entire trunk. The pith is quite thick, usually
+one-eighth to one-fifth inch in southern species, though
+much less so in white pine, and is very thin, one-fifteenth
+to one twenty-fifth inch in cypress, cedar, and larch.</p>
+
+<p>In woods with a thick pith, the pith is finest at the
+stump, grows rapidly thicker toward the top, and becomes
+thinner again in the crown and limbs, the first one
+to five rings adjoining it behaving similarly.</p>
+
+<p>What is called the pith was once the seedling tree, and
+in many of the pines and firs, especially after they have
+been seasoning for a good while, this is distinctly noticeable
+in the center of the log, and detaches itself from the
+surrounding wood.</p>
+
+
+<h4>Sap and Heartwood</h4>
+
+<p>Wood is composed of duramen or heartwood, and alburnum
+or sapwood, and when dry consists approximately
+of 49 per cent by weight of carbon, 6 per cent of hydrogen,
+44 per cent of oxygen, and 1 per cent of ash, which is fairly
+uniform for all species. The sapwood is the external and<span class='pagenum'><a name="Page_9" id="Page_9">[9]</a></span>
+youngest portion of the tree, and often constitutes a very
+considerable proportion of it. It lies next the bark, and
+after a course of years, sometimes many, as in the case of
+oaks, sometimes few, as in the case of firs, it becomes
+hardened and ultimately forms the duramen or heartwood.
+Sapwood is generally of a white or light color, almost invariably
+lighter in color than the heartwood, and is very
+conspicuous in the darker-colored woods, as for instance
+the yellow sapwood of mahogany and similiar colored
+woods, and the reddish brown heartwood; or the yellow
+sapwood of <i>Lignum-vitae</i> and the dark green heartwood.
+Sapwood forms a much larger proportion of some trees
+than others, but being on the outer circumference it always
+forms a large proportion of the timber, and even in sound,
+hard pine will be from 40 per cent to 60 per cent of the
+tree and in some cases much more. It is really imperfect
+wood, while the duramen or heartwood is the perfect wood;
+the heartwood of the mature tree was the sapwood of its
+earlier years. Young trees when cut down are almost
+all sapwood, and practically useless as good, sound timber;
+it is, however, through the sapwood that the life-giving
+juices which sustain the tree arise from the soil, and if the
+sapwood be cut through, as is done when "girdling," the
+tree quickly dies, as it can derive no further nourishment
+from the soil. Although absolutely necessary to the growing
+tree, sapwood is often objectionable to the user, as it
+is the first part to decay. In this sapwood many cells are
+active, store up starch, and otherwise assist in the life
+processes of the tree, although only the last or outer layer
+of cells forms the growing part, and the true life of the tree.</p>
+
+<p>The duramen or heartwood is the inner, darker part of
+the log. In the heartwood all the cells are lifeless cases,
+and serve only the mechanical function of keeping the
+tree from breaking under its own great weight or from
+being laid low by the winds. The darker color of the
+heartwood is due to infiltration of chemical substances
+into the cell walls, but the cavities of the cells in pine are
+not filled up, as is sometimes believed, nor do their walls
+grow thicker, nor are the walls any more liquified than in
+the sapwood.<span class='pagenum'><a name="Page_10" id="Page_10">[10]</a></span></p>
+
+<p>Sapwood varies in width and in the number of rings
+which it contains even in different parts of the same tree.
+The same year's growth which is sapwood in one part of
+a disk may be heartwood in another. Sapwood is widest
+in the main part of the stem and often varies within considerable
+limits and without apparent regularity. Generally,
+it becomes narrower toward the top and in the
+limbs, its width varying with the diameter, and being
+the least in a given disk on the side which has the shortest
+radius. Sapwood of old and stunted pines is composed
+of more rings than that of young and thrifty specimens.
+Thus in a pine two hundred and fifty years old a layer of
+wood or an annual ring does not change from sapwood to
+heartwood until seventy or eighty years after it is formed,
+while in a tree one hundred years old or less it remains
+sapwood only from thirty to sixty years.</p>
+
+<p>The width of the sapwood varies considerably for different
+kinds of pine. It is small for long-leaf and white
+pine and great for loblolly and Norway pines. Occupying
+the peripheral part of the trunk, the proportion which
+it forms of the entire mass of the stem is always great.
+Thus even in old long-leaf pines, the sapwood forms 40
+per cent of the merchantable log, while in the loblolly
+and in all young trees the sapwood forms the bulk of the
+wood.</p>
+
+
+<h4>The Annual or Yearly Rings</h4>
+
+<p>The concentric annual or yearly rings which appear on
+the end face of a log are cross-sections of so many thin
+layers of wood. Each such layer forms an envelope around
+its inner neighbor, and is in turn covered by the adjoining
+layer without, so that the whole stem is built up of
+a series of thin, hollow cylinders, or rather cones.</p>
+
+<p>A new layer of wood is formed each season, covering
+the entire stem, as well as all the living branches. The
+thickness of this layer or the width of the yearly ring
+varies greatly in different trees, and also in different parts
+of the same tree.</p>
+
+<p>In a normally-grown, thrifty pine log the rings are widest
+near the pith, growing more and more narrow toward<span class='pagenum'><a name="Page_11" id="Page_11">[11]</a></span>
+the bark. Thus the central twenty rings in a disk of an
+old long-leaf pine may each be one-eighth to one-sixth
+inch wide, while the twenty rings next to the bark may
+average only one-thirtieth inch.</p>
+
+<p>In our forest trees, rings of one-half inch in width occur
+only near the center in disks of very thrifty trees, of both
+conifers and hardwoods. One-twelfth inch represents good,
+thrifty growth, and the minimum width of one two hundred
+inch is often seen in stunted spruce and pine. The
+average width of rings in well-grown, old white pine will
+vary from one-twelfth to one-eighteenth inch, while in the
+slower growing long-leaf pine it may be one twenty-fifth
+to one-thirtieth of an inch. The same layer of wood
+is widest near the stump in very thrifty young trees,
+especially if grown in the open park; but in old forest
+trees the same year's growth is wider at the upper part
+of the tree, being narrowest near the stump, and often
+also near the very tip of the stem. Generally the rings
+are widest near the center, growing narrower toward the
+bark.</p>
+
+<p>In logs from stunted trees the order is often reversed,
+the interior rings being thin and the outer rings widest.
+Frequently, too, zones or bands of very narrow rings,
+representing unfavorable periods of growth, disturb the
+general regularity.</p>
+
+<p>Few trees, even among pines, furnish a log with truly
+circular cross-section. Usually it is an oval, and at the
+stump commonly quite an irregular figure. Moreover,
+even in very regular or circular disks the pith is rarely in
+the center, and frequently one radius is conspicuously
+longer than its opposite, the width of some rings, if not
+all, being greater on one side than on the other. This is
+nearly always so in the limbs, the lower radius exceeding
+the upper. In extreme cases, especially in the limbs, a
+ring is frequently conspicuous on one side, and almost
+or entirely lost to view on the other. Where the rings
+are extremely narrow, the dark portion of the ring is often
+wanting, the color being quite uniform and light. The
+greater regularity or irregularity of the annual rings has
+much to do with the technical qualities of the timber.<span class='pagenum'><a name="Page_12" id="Page_12">[12]</a></span></p>
+
+
+<h4>Spring- and Summer-Wood</h4>
+
+<p>Examining the rings more closely, it is noticed that
+each ring is made up of an inner, softer, light-colored and
+an outer, or peripheral, firmer and darker-colored portion.
+Being formed in the forepart of the season, the inner,
+light-colored part is termed spring-wood, the outer, darker-portioned
+being the summer-wood of the ring. Since the
+latter is very heavy and firm it determines to a very large
+extent the weight and strength of the wood, and as its
+darker color influences the shade of color of the entire
+piece of wood, this color effect becomes a valuable aid in
+distinguishing heavy and strong from light and soft pine
+wood.</p>
+
+<p>In most hard pines, like the long-leaf, the dark summer-wood
+appears as a distinct band, so that the yearly ring
+is composed of two sharply defined bands&mdash;an inner,
+the spring-wood, and an outer, the summer-wood. But
+in some cases, even in hard pines, and normally in the
+woods of white pines, the spring-wood passes gradually
+into the darker summer-wood, so that a darkly defined
+line occurs only where the spring-wood of one ring abuts
+against the summer-wood of its neighbor. It is this clearly
+defined line which enables the eye to distinguish even the
+very narrow lines in old pines and spruces.</p>
+
+<div class="figright" style="width: 300px;"><p class="anchor"><a name="Fig_1" id="Fig_1"></a></p>
+<img src="images/fig01.jpg" width="300" height="381" alt="Board of Pine" title="Board of Pine" />
+
+<p class="caption">Fig. 1. Board of Pine. CS, cross-section; RS,
+radial section; TS, tangential section;
+<i>sw</i>, summer-wood; <i>spw</i>, spring-wood.</p>
+</div>
+
+<p>In some cases, especially in the trunks of Southern pines,
+and normally on the lower side of pine limbs, there occur
+dark bands of wood in the spring-wood portion of the ring,
+giving rise to false rings, which mislead in a superficial
+counting of rings. In the disks cut from limbs these
+dark bands often occupy the greater part of the ring, and
+appear as "lunes," or sickle-shaped figures. The wood of
+these dark bands is similar to that of the true summer-wood.
+The cells have thick walls, but usually the compressed
+or flattened form. Normally, the summer-wood
+forms a greater proportion of the rings in the part of the
+tree formed during the period of thriftiest growth. In
+an old tree this proportion is very small in the first two
+to five rings about the pith, and also in the part next to
+the bark, the intermediate part showing a greater proportion<span class='pagenum'><a name="Page_13" id="Page_13">[13]</a></span>
+of summer-wood. It is also greatest in a disk
+taken from near the stump, and decreases upward in the
+stem, thus fully accounting for the difference in weight
+and firmness of the wood of these different parts.</p>
+
+
+<p>In the long-leaf pine the summer-wood often forms
+scarcely ten per cent of the wood in the central five rings;
+forty to fifty per cent of the next one hundred rings, about
+thirty per cent of the next fifty, and only about twenty
+per cent in the fifty
+rings next to the
+bark. It averages
+forty-five per cent of
+the wood of the
+stump and only
+twenty-four per cent
+of that of the top.</p>
+
+<p>Sawing the log into
+boards, the yearly
+rings are represented
+on the board faces
+of the middle board
+(radial sections) by
+narrow parallel strips
+(<a href="#Fig_1">see Fig. 1</a>), an inner,
+lighter stripe
+and its outer, darker
+neighbor always corresponding
+to one
+annual ring.</p>
+
+<p>On the faces of the
+boards nearest the slab (tangential or bastard boards) the
+several years' growth should also appear as parallel, but
+much broader stripes. This they do if the log is short
+and very perfect. Usually a variety of pleasing patterns
+is displayed on the boards, depending on the position of
+the saw cut and on the regularity of growth of the log
+(<a href="#Fig_1">see Fig. 1</a>). Where the cut passes through a prominence
+(bump or crook) of the log, irregular, concentric circlets
+and ovals are produced, and on almost all tangent boards
+arrow or V-shaped forms occur.<span class='pagenum'><a name="Page_14" id="Page_14">[14]</a></span></p>
+
+
+<h4>Anatomical Structure</h4>
+
+<p>Holding a well-smoothed disk or cross-section one-eighth
+inch thick toward the light, it is readily seen that
+pine wood is a very porous structure. If viewed with a
+strong magnifier, the little tubes, especially in the spring-wood
+of the rings, are easily distinguished, and their arrangement
+in regular, straight, radial rows is apparent.</p>
+
+<div class="figleft" style="width: 300px;"><p class="anchor"><a name="Fig_2" id="Fig_2"></a></p>
+<img src="images/fig02.jpg" width="300" height="320" alt="Wood of Spruce" title="Wood of Spruce" />
+
+
+<p class="caption">Fig. 2. Wood of Spruce. 1, natural size; 2,
+small part of one ring magnified 100
+times. The vertical tubes are wood
+fibres, in this case all "tracheids." <i>m</i>,
+medullary or pith ray; <i>n</i>, transverse
+tracheids of ray; <i>a</i>, <i>b</i>, and <i>c</i>, bordered
+pits of the tracheids, more enlarged.</p>
+</div>
+
+<p>Scattered through the summer-wood portion of the
+rings, numerous irregular grayish dots (the resin ducts)
+disturb the uniformity
+and regularity of
+the structure. Magnified
+one hundred
+times, a piece of
+spruce, which is similar
+to pine, presents
+a picture like that
+shown in <a href="#Fig_2">Fig. 2</a>.
+Only short pieces of
+the tubes or cells of
+which the wood is
+composed are represented
+in the picture.
+The total length of
+these fibres is from
+one-twentieth to one-fifth
+inch, being the
+smallest near the
+pith, and is fifty to
+one hundred times
+as great as their
+width (see <a href="#Fig_3">Fig. 3</a>).
+They are tapered and closed at their ends, polygonal or
+rounded and thin-walled, with large cavity, lumen or internal
+space in the spring-wood, and thick-walled and
+flattened radially, with the internal space or lumen much
+reduced in the summer-wood (see right-hand portion
+of <a href="#Fig_2">Fig. 2</a>). This flattening, together with the thicker walls
+of the cells, which reduces the lumen, causes the greater<span class='pagenum'><a name="Page_15" id="Page_15">[15]</a></span>
+firmness and darker color of the summer-wood. There
+is more material in the same volume. As shown in the
+figure, the tubes, cells or "tracheids" are decorated on
+their walls by circlet-like structures, the "bordered pits,"
+sections of which are seen more magnified as <i>a</i>, <i>b</i>, and <i>c</i>,
+<a href="#Fig_2">Fig. 2</a>. These pits are in the nature of pores, covered
+by very thin membranes, and serve as waterways
+between the cells or tracheids. The dark
+lines on the side of the smaller piece (1, <a href="#Fig_2">Fig. 2</a>)
+appear when magnified (in 2, <a href="#Fig_2">Fig. 2</a>) as tiers
+of eight to ten rows of cells, which run radially
+(parallel to the rows of tubes or tracheids),
+and are seen as bands on the radial face and
+as rows of pores on the tangential face. These
+bands or tiers of cell rows are the medullary
+rays or pith rays, and are common to all our
+lumber woods.</p>
+
+<div class="figright" style="width: 50px;"><p class="anchor"><a name="Fig_3" id="Fig_3"></a></p>
+<img src="images/fig03.jpg" width="50" height="383" alt="Group of fibres from pine wood" title="Group of fibres from pine wood" />
+</div>
+
+<p>In the pines and other conifers they are quite
+small, but they can readily be seen even without
+a magnifier. If a radial surface of split-wood
+(not smoothed) is examined, the entire
+radial face will be seen almost covered with
+these tiny structures, which appear as fine but
+conspicuous cross-lines. As shown in <a href="#Fig_2">Fig. 2</a>, the
+cells of the medullary or pith are smaller and
+very much shorter than the wood fibre or
+tracheids, and their long axis is at right angles
+to that of the fiber.</p>
+
+<p>In pines and spruces the cells of the upper
+and lower rows of each tier or pith ray have
+"bordered" pits, like those of the wood fibre
+or tracheids proper, but the cells of the intermediate
+rows in the rays of cedars, etc., have
+only "simple" pits, <i>i.e.</i>, pits devoid of the
+saucer-like "border" or rim. In pine, many
+of the pith rays are larger than the majority,<span class='pagenum'><a name="Page_16" id="Page_16">[16]</a></span>
+each containing a whitish line, the horizontal resin duct,
+which, though much smaller, resembles the vertical ducts
+on the cross-section. The larger vertical resin ducts are
+best observed on removal of the bark from a fresh piece
+of white pine cut in the winter where they appear as conspicuous
+white lines, extending often for many inches up
+and down the stem. Neither the horizontal nor the vertical
+resin ducts are vessels or cells, but are openings between
+cells, <i>i.e.</i>, intercellular spaces, in which the resin accumulates,
+freely oozing out when the ducts of a fresh piece of
+sapwood are cut. They are present only in our coniferous
+woods, and even here they are restricted to pine, spruce,
+and larch, and are normally absent in fir, cedar, cypress,
+and yew. Altogether, the structure of coniferous woods
+is very simple and regular, the bulk being made up of the
+small fibres called tracheids, the disturbing elements of
+pith rays and resin ducts being insignificant, and hence
+the great uniformity and great technical value of coniferous
+woods.<span class='pagenum'><a name="Page_17" id="Page_17">[17]</a></span></p>
+
+<p class="caption" style="margin-left: 2em">Fig. 3. Group of Fibres from Pine Wood. Partly schematic. The little
+circles are "border pits" (see <a href="#Fig_2">Fig. 2</a>, <i>a-c</i>). The transverse rows of
+square pits indicate the places of contact of these fibres and the cells
+of the neighboring pith rays. Magnified about 25 times.</p>
+
+<h3><a name="LIST_OF_IMPORTANT_CONIFEROUS_WOODS" id="LIST_OF_IMPORTANT_CONIFEROUS_WOODS"></a>LIST OF IMPORTANT CONIFEROUS WOODS</h3>
+
+
+<h4>CEDAR</h4>
+
+<p>Light soft, stiff, not strong, of fine texture. Sap- and
+heartwood distinct, the former lighter, the latter a dull
+grayish brown or red. The wood seasons rapidly, shrinks
+and checks but little, and is very durable in contact with
+the soil. Used like soft pine, but owing to its great durability
+preferred for shingles, etc. Cedars usually occur
+scattered, but they form in certain localities forests of
+considerable extent.</p>
+
+
+<h4>(<i>a</i>) White Cedars</h4>
+
+<p class="negative1"><b>1. White Cedar</b> (<i>Thuya occidentalis</i>) (Arborvit&aelig;, Tree of
+Life). Heartwood light yellowish brown, sapwood
+nearly white. Wood light, soft, not strong, of fine
+texture, very durable in contact with the soil, very
+fragrant. Scattered along streams and lakes, frequently
+covering extensive swamps; rarely large
+enough for lumber, but commonly used for fence
+posts, rails, railway ties, and shingles. This species
+has been extensively cultivated as an ornamental tree
+for at least a century. Maine to Minnesota and
+northward.</p>
+
+<p class="negative1"><b>2. Canoe Cedar</b> (<i>Thuya gigantea</i>) (Red Cedar of the West).
+In Oregon and Washington a very large tree, covering
+extensive swamps; in the mountains much smaller,
+skirting the water courses. An important lumber
+tree. The wood takes a fine polish; suitable for
+interior finishing, as there is much variety of shading
+in the color. Washington to northern California
+and eastward to Montana.</p>
+
+<p class="negative1"><b>3. White Cedar</b> (<i>Cham&aelig;cyparis thyoides</i>). Medium-sized
+tree. Heartwood light brown with rose tinge, sapwood<span class='pagenum'><a name="Page_18" id="Page_18">[18]</a></span>
+paler. Wood light, soft, not strong, close-grained,
+easily worked, very durable in contact with
+the soil and very fragrant. Used in boatbuilding
+cooperage, interior finish, fence posts, railway ties,
+etc. Along the coast from Maine to Mississippi.</p>
+
+<p class="negative1"><b>4. White Cedar</b> (<i>Cham&aelig;cyparis Lawsoniana</i>) (Port Orford
+Cedar, Oregon Cedar, Lawson's Cypress, Ginger
+Pine). A very large tree. A fine, close-grained,
+yellowish-white, durable timber, elastic, easily worked,
+free of knots, and fragrant. Extensively cut for
+lumber; heavier and stronger than any of the preceding.
+Along the coast line of Oregon.</p>
+
+<p class="negative1"><b>5. White Cedar</b> (<i>Libocedrus decurrens</i>) (Incense Cedar).
+A large tree, abundantly scattered among pine and
+fir. Wood fine-grained. Cascades and Sierra Nevada
+Mountains of Oregon and California.</p>
+
+<p class="negative1"><b>6. Yellow Cedar</b> (<i>Cupressus nootkatensis</i>) (Alaska Cedar,
+Alaska Cypress). A very large tree, much used for
+panelling and furniture. A fine, close-grained, yellowish
+white, durable timber, easily worked. Along
+the coast line of Oregon north.</p>
+
+
+<h4>(<i>b</i>) Red Cedars</h4>
+
+<p class="negative1"><b>7. Red Cedar</b> (<i>Juniperus Virginiana</i>) (Savin Juniper,
+Juniper, Red Juniper, Juniper Bush, Pencil Cedar).
+Heartwood dull red color, thin sapwood nearly white.
+Close even grain, compact structure. Wood light,
+soft, weak, brittle, easily worked, durable in contact
+with the soil, and fragrant. Used for ties, posts,
+interior finish, pencil cases, cigar boxes, silos, tanks,
+and especially for lead pencils, for which purpose
+alone several million feet are cut each year. A small
+to medium-sized tree scattered through the forests,
+or in the West sparsely covering extensive areas (cedar
+brakes). The red cedar is the most widely distributed
+conifer of the United States, occurring from the Atlantic
+to the Pacific, and from Florida to Minnesota.<span class='pagenum'><a name="Page_19" id="Page_19">[19]</a></span>
+Attains a suitable size for lumber only in the Southern,
+and more especially the Gulf States.</p>
+
+<p class="negative1"><b>8. Red Cedar</b> (<i>Juniperus communis</i>) (Ground Cedar).
+Small-sized tree, its maximum height being about
+25 feet. It is found widely distributed throughout
+the Northern hemisphere. Wood in its quality similar
+to the preceding. The fruit of this species is gathered
+in large quantities and used in the manufacture of
+gin; whose peculiar flavor and medicinal properties
+are due to the oil of Juniper berries, which is secured
+by adding the crushed fruit to undistilled grain spirit,
+or by allowing the vapor to pass over it before condensation.
+Used locally for construction purposes,
+fence posts, etc. Ranges from Greenland to Alaska,
+in the East, southward to Pennsylvania and northern
+Nebraska; in the Rocky Mountains to Texas, Mexico,
+and Arizona.</p>
+
+<p class="negative1"><b>9. Redwood</b> (<i>Sequoia sempervirens</i>) (Sequoia, California
+Redwood, Coast Redwood). Wood in its quality
+and uses like white cedar. Thick, red heartwood,
+changing to reddish brown when seasoned. Thin
+sapwood, nearly white, coarse, straight grain, compact
+structure. Light, not strong, soft, very durable in
+contact with the soil, not resinous, easily worked,
+does not burn easily, receives high polish. Used for
+timber, shingles, flumes, fence posts, coffins, railway ties,
+water pipes, interior decorations, and cabinetmaking.
+A very large tree, limited to the coast ranges of California,
+and forming considerable forests, which are
+rapidly being converted into lumber.</p>
+
+
+<h4>CYPRESS</h4>
+
+<p class="negative"><b>10. Cypress</b> (<i>Taxodium distinchum</i>) (Bald Cypress, Black,
+White, and Red Cypress, Pecky Cypress). Wood in
+its appearance, quality, and uses similar to white
+cedar. "Black" and "White Cypress" are heavy
+and light forms of the same species. Heartwood
+brownish; sapwood nearly white. Wood close,<span class='pagenum'><a name="Page_20" id="Page_20">[20]</a></span>
+straight-grain, frequently full of small holes caused by
+disease known as "pecky cypress." Greasy appearance
+and feeling. Wood light, soft, not strong,
+durable in contact with the soil, takes a fine polish.
+Green wood often very heavy. Used for carpentry,
+building construction, shingles, cooperage, railway
+ties, silos, tanks, vehicles, and washing machines.
+The cypress is a large, deciduous tree, inhabiting
+swampy lands, and along rivers and coasts of the
+Southern parts of the United States. Grows to a
+height of 150 feet and 12 feet in diameter.</p>
+
+
+<h4>FIR</h4>
+
+<p>This name is frequently applied to wood and to trees
+which are not fir; most commonly to spruce, but also,
+especially in English markets, to pine. It resembles
+spruce, but is easily distinguished from it, as well as from
+pine and larch, by the absence of resin ducts. Quality,
+uses, and habits similar to spruce.</p>
+
+<p class="negative"><b>11. Balsam Fir</b> (<i>Abies balsamea</i>) (Balsam, Fir Tree, Balm
+of Gilead Fir). Heartwood white to brownish; sapwood
+lighter color; coarse-grained, compact structure,
+satiny. Wood light, not durable or strong, resinous,
+easily split. Used for boxes, crates, doors, millwork,
+cheap lumber, paper pulp. Inferior to white pine
+or spruce, yet often mixed and sold with these species
+in the lumber market. A medium-sized tree scattered
+throughout the northern pineries, and cut in lumber
+operations whenever of sufficient size. Minnesota
+to Maine and northward.</p>
+
+<p class="negative"><b>12. White Fir</b> (<i>Abies grandis</i> and <i>Abies concolor</i>). Medium-
+to very large-sized tree, forming an important part of
+most of the Western mountain forests, and furnishes
+much of the lumber of the respective regions. The
+former occurs from Vancouver to California, and the
+latter from Oregon to Arizona and eastward to Colorado
+and Mexico. The wood is soft and light, coarse-grained,
+not unlike the "Swiss pine" of Europe, but<span class='pagenum'><a name="Page_21" id="Page_21">[21]</a></span>
+darker and firmer, and is not suitable for any purpose
+requiring strength. It is used for boxes, barrels, and
+to a small extent for wood pulp.</p>
+
+<p class="negative"><b>13. White Fir</b> (<i>Abies amabalis</i>). Good-sized tree, often
+forming extensive mountain forests. Wood similar
+in quality and uses to <i>Abies grandis</i>. Cascade Mountains
+of Washington and Oregon.</p>
+
+<p class="negative"><b>14. Red Fir</b> (<i>Abies nobilis</i>) (Noble Fir) (not to be confounded
+with Douglas spruce. See No. 40). Large
+to very large-sized tree, forming extensive forests on
+the slope of the mountains between 3,000 and 4,000
+feet elevation. Cascade Mountains of Oregon.</p>
+
+<p class="negative"><b>15. Red Fir</b> (<i>Abies magnifica</i>). Very large-sized tree,
+forming forests about the base of Mount Shasta.
+Sierra Nevada Mountains of California, from Mount
+Shasta southward.</p>
+
+
+<h4>HEMLOCK</h4>
+
+<p>Light to medium weight, soft, stiff, but brittle, commonly
+cross-grained, rough and splintery. Sapwood and heartwood
+not well defined. The wood of a light reddish-gray
+color, free from resin ducts, moderately durable, shrinks
+and warps considerably in drying, wears rough, retains
+nails firmly. Used principally for dimension stuff and
+timbers. Hemlocks are medium- to large-sized trees,
+commonly scattered among broad-leaved trees and conifers,
+but often forming forests of almost pure growth.</p>
+
+<p class="negative"><b>16. Hemlock</b> (<i>Tsuga canadensis</i>) (Hemlock Spruce,
+Peruche). Medium-sized tree, furnishes almost all
+the hemlock of the Eastern market. Maine to Wisconsin,
+also following the Alleghanies southward to
+Georgia and Alabama.</p>
+
+<p class="negative"><b>17. Hemlock</b> (<i>Tsuga mertensiana</i>). Large-sized tree,
+wood claimed to be heavier and harder than the
+Eastern species and of superior quality. Used for
+pulp wood, floors, panels, and newels. It is not<span class='pagenum'><a name="Page_22" id="Page_22">[22]</a></span>
+suitable for heavy construction, especially where exposed
+to the weather, it is straight in grain and will
+take a good polish. Not adapted for use partly in
+and partly out of the ground; in fresh water as piles
+will last about ten years, but as it is softer than fir
+it is less able to stand driving successfully. Washington
+to California and eastward to Montana.</p>
+
+
+<h4>LARCH or TAMARACK</h4>
+
+<p>Wood like the best of hard pine both in appearance,
+quality, and uses, and owing to its great durability somewhat
+preferred in shipbuilding, for telegraph poles, and
+railway ties. In its structure it resembles spruce. The
+larches are deciduous trees, occasionally covering considerable
+areas, but usually scattered among other conifers.</p>
+
+<p class="negative"><b>18. Tamarack</b> (<i>Larix laricina</i> var. <i>Americana</i>) (Larch,
+Black Larch, American Larch, Hacmatac). Heartwood
+light brown in color, sapwood nearly white,
+coarse conspicuous grain, compact structure, annual
+rings pronounced. Wood heavy, hard, very strong,
+durable in contact with the soil. Used for railway
+ties, fence posts, sills, ship timbers, telegraph poles,
+flagstaffs. Medium-sized tree, often covering swamps,
+in which case it is smaller and of poor quality. Maine
+to Minnesota, and southward to Pennsylvania.</p>
+
+<p class="negative"><b>19. Tamarack</b> (<i>Larix occidentalis</i>) (Western Larch, Larch).
+Large-sized trees, scattered, locally abundant. Is
+little inferior to oak in strength and durability.
+Heartwood of a light brown color with lighter sapwood,
+has a fine, slightly satiny grain, and is
+fairly free from knots; the annual rings are distant.
+Used for railway ties and shipbuilding. Washington
+and Oregon to Montana.</p>
+
+
+<h4>PINE</h4>
+
+<p>Very variable, very light and soft in "soft" pine, such
+as white pine; of medium weight to heavy and quite
+hard in "hard" pine, of which the long-leaf or Georgia<span class='pagenum'><a name="Page_23" id="Page_23">[23]</a></span>
+pine is the extreme form. Usually it is stiff, quite strong,
+of even texture, and more or less resinous. The sapwood
+is yellowish white; the heartwood orange brown. Pine
+shrinks moderately, seasons rapidly and without much
+injury; it works easily, is never too hard to nail (unlike
+oak or hickory); it is mostly quite durable when in contact
+with the soil, and if well seasoned is not subject to
+the attacks of boring insects. The heavier the wood, the
+darker, stronger, and harder it is, and the more it shrinks
+and checks when seasoning. Pine is used more extensively
+than any other wood. It is the principal wood in
+carpentry, as well as in all heavy construction, bridges,
+trestles, etc. It is also used in almost every other wood
+industry; for spars, masts, planks, and timbers in shipbuilding,
+in car and wagon construction, in cooperage and
+woodenware; for crates and boxes, in furniture work, for
+toys and patterns, water pipes, excelsior, etc. Pines are
+usually large-sized trees with few branches, the straight,
+cylindrical, useful stem forming by far the greatest part
+of the tree. They occur gregariously, forming vast forests,
+a fact which greatly facilitates their exploitation. Of the
+many special terms applied to pine as lumber, denoting
+sometimes differences in quality, the following deserve
+attention: "White pine," "pumpkin pine," "soft pine,"
+in the Eastern markets refer to the wood of the white
+pine (<i>Pinus strobus</i>), and on the Pacific Coast to that of
+the sugar pine (<i>Pinus lambertiana</i>). "Yellow pine" is
+applied in the trade to all the Southern lumber pines; in
+the Northwest it is also applied to the pitch pine (<i>Pinus
+regida</i>); in the West it refers mostly to the bull pine (<i>Pinus
+ponderosa</i>). "Yellow long-leaf pine" (Georgia pine),
+chiefly used in advertisements, refers to the long-leaf
+Pine (<i>Pinus palustris</i>).</p>
+
+
+<h4>(<i>a</i>) Soft Pines</h4>
+
+<p class="negative"><b>20. White Pine</b> (<i>Pinus strobus</i>) (Soft Pine, Pumpkin Pine,
+Weymouth Pine, Yellow Deal). Large to very large-sized
+tree, reaching a height of 80 to 100 feet or more,
+and in some instances 7 or 8 feet in diameter. For
+the last fifty years the most important timber tree<span class='pagenum'><a name="Page_24" id="Page_24">[24]</a></span>
+of the United States, furnishing the best quality of
+soft pine. Heartwood cream white; sapwood nearly
+white. Close straight grain, compact structure; comparatively
+free from knots and resin. Soft, uniform;
+seasons well; easy to work; nails without splitting;
+fairly durable in contact with the soil; and shrinks
+less than other species of pine. Paints well. Used
+for carpentry, construction, building, spars, masts,
+matches, boxes, etc., etc., etc.</p>
+
+<p class="negative"><b>21. Sugar Pine</b> (<i>Pinus lambertiana</i>) (White Pine, Pumpkin
+Pine, Soft Pine). A very large tree, forming extensive
+forests in the Rocky Mountains and furnishing
+most of the timber of the western United States. It
+is confined to Oregon and California, and grows at
+from 1,500 to 8,000 feet above sea level. Has an
+average height of 150 to 175 feet and a diameter of
+4 to 5 feet, with a maximum height of 235 feet and 12
+feet in diameter. The wood is soft, durable, straight-grained,
+easily worked, very resinous, and has a
+satiny luster which makes it appreciated for interior
+work. It is extensively used for doors, blinds, sashes,
+and interior finish, also for druggists' drawers, owing
+to its freedom from odor, for oars, mouldings, shipbuilding,
+cooperage, shingles, and fruit boxes. Oregon
+and California.</p>
+
+<p class="negative"><b>22. White Pine</b> (<i>Pinus monticolo</i>). A large tree, at home
+in Montana, Idaho, and the Pacific States. Most
+common and locally used in northern Idaho.</p>
+
+<p class="negative"><b>23. White Pine</b> (<i>Pinus flexilis</i>). A small-sized tree,
+forming mountain forests of considerable extent and
+locally used. Eastern Rocky Mountain slopes, Montana
+to New Mexico.</p>
+
+
+<h4>(<i>b</i>) Hard Pines</h4>
+
+<p class="negative"><b>24. Long-Leaf Pine</b> (<i>Pinus palustris</i>) (Georgia Pine,
+Southern Pine, Yellow Pine, Southern Hard Pine,
+Long-straw Pine, etc.). Large-sized tree. This
+species furnishes the hardest and most durable as<span class='pagenum'><a name="Page_25" id="Page_25">[25]</a></span>
+well as one of the strongest pine timbers in the market.
+Heartwood orange, sapwood lighter color, the annual
+rings are strongly marked, and it is full of resinous
+matter, making it very durable, but difficult to work.
+It is hard, dense, and strong, fairly free from knots,
+straight-grained, and one of the best timbers for
+heavy engineering work where great strength, long
+span, and durability are required. Used for heavy
+construction, shipbuilding, cars, docks, beams, ties,
+flooring, and interior decoration. Coast region from
+North Carolina to Texas.</p>
+
+<p class="negative"><b>25. Bull Pine</b> (<i>Pinus ponderosa</i>) (Yellow Pine, Western
+Yellow Pine, Western Pine, Western White Pine,
+California White Pine). Medium- to very large-sized
+tree, forming extensive forests in the Pacific and
+Rocky Mountain regions. Heartwood reddish brown,
+sapwood yellowish white, and there is often a good
+deal of it. The resinous smell of the wood is very
+remarkable. It is extensively used for beams, flooring,
+ceilings, and building work generally.</p>
+
+<p class="negative"><b>26. Bull Pine</b> (<i>Pinus Jeffreyi</i>) (Black Pine). Large-sized
+tree, wood resembles <i>Pinus ponderosa</i> and replacing
+same at high altitudes. Used locally in
+California.</p>
+
+<p class="negative"><b>27. Loblolly Pine</b> (<i>Pinus t&aelig;da</i>) (Slash Pine, Old Field
+Pine, Rosemary Pine, Sap Pine, Short-straw Pine).
+A large-sized tree, forms extensive forests. Wider-ringed,
+coarser, lighter, softer, with more sapwood
+than the long-leaf pine, but the two are often confounded
+in the market. The more Northern tree
+produces lumber which is weak, brittle, coarse-grained,
+and not durable, the Southern tree produces a better
+quality wood. Both are very resinous. This is the
+common lumber pine from Virginia to South Carolina,
+and is found extensively in Arkansas and Texas.
+Southern States, Virginia to Texas and Arkansas.</p>
+
+<p class="negative"><b>28. Norway Pine</b> (<i>Pinus resinosa</i>) (American Red Pine,
+Canadian Pine). Large-sized tree, never forming<span class='pagenum'><a name="Page_26" id="Page_26">[26]</a></span>
+forests, usually scattered or in small groves, together
+with white pine. Largely sapwood and hence not
+durable. Heartwood reddish white, with fine, clear
+grain, fairly tough and elastic, not liable to warp and
+split. Used for building construction, bridges, piles,
+masts, and spars. Minnesota to Michigan; also in
+New England to Pennsylvania.</p>
+
+<p class="negative"><b>29. Short-Leaf Pine</b> (<i>Pinus echinata</i>) (Slash Pine, Spruce
+Pine, Carolina Pine, Yellow Pine, Old Field Pine,
+Hard Pine). A medium- to large-sized tree, resembling
+loblolly pine, often approaches in its wood the
+Norway pine. Heartwood orange, sapwood lighter;
+compact structure, apt to be variable in appearance
+in cross-section. Wood usually hard, tough, strong,
+durable, resinous. A valuable timber tree, sometimes
+worked for turpentine. Used for heavy construction,
+shipbuilding, cars, docks, beams, ties, flooring, and
+house trim. <i>Pinus echinata</i>, <i>palustris</i>, and <i>t&aelig;da</i> are
+very similar in character, of thin wood and very difficult
+to distinguish one from another. As a rule, however,
+<i>palustris</i> (Long-leaf Pine) has the smallest and
+most uniform growth rings, and <i>Pinus t&aelig;da</i> (Loblolly
+Pine) has the largest. All are apt to be bunched
+together in the lumber market as Southern Hard
+Pine. All are used for the same purposes. Short-leaf
+is the common lumber pine of Missouri and
+Arkansas. North Carolina to Texas and Missouri.</p>
+
+<p class="negative"><b>30. Cuban Pine</b> (<i>Pinus cubensis</i>) (Slash Pine, Swamp
+Pine, Bastard Pine, Meadow Pine). Resembles long-leaf
+pine, but commonly has a wider sapwood and
+coarser grain. Does not enter the markets to any
+extent. Along the coast from South Carolina to
+Louisiana.</p>
+
+<p class="negative"><b>31. Pitch Pine</b> (<i>Pinus rigida</i>) (Torch Pine). A small to
+medium-sized tree. Heartwood light brown or red,
+sapwood yellowish white. Wood light, soft, not
+strong, coarse-grained, durable, very resinous. Used
+locally for lumber, fuel, and charcoal. Coast regions<span class='pagenum'><a name="Page_27" id="Page_27">[27]</a></span>
+from New York to Georgia, and along the mountains
+to Kentucky.</p>
+
+<p class="negative"><b>32. Black Pine</b> (<i>Pinus murryana</i>) (Lodge-pole Pine,
+Tamarack). Small-sized tree. Rocky Mountains
+and Pacific regions.</p>
+
+<p class="negative"><b>33. Jersey Pine</b> (<i>Pinus inops</i> var. <i>Virginiana</i>) (Scrub
+Pine). Small-sized tree. Along the coast from New
+York to Georgia and along the mountains to Kentucky.</p>
+
+<p class="negative"><b>34. Gray Pine</b> (<i>Pinus divaricata</i> var. <i>banksiana</i>) (Scrub
+Pine, Jack Pine). Medium- to large-sized tree.
+Heartwood pale brown, rarely yellow; sapwood nearly
+white. Wood light, soft, not strong, close-grained.
+Used for fuel, railway ties, and fence posts. In days
+gone by the Indians preferred this species for frames
+of canoes. Maine, Vermont, and Michigan to Minnesota.</p>
+
+
+<h4>REDWOOD (See Cedar)</h4>
+
+<h4>SPRUCE</h4>
+
+<p>Resembles soft pine, is light, very soft, stiff, moderately
+strong, less resinous than pine; has no distinct heartwood,
+and is of whitish color. Used like soft pine, but also employed
+as resonance wood in musical instruments and
+preferred for paper pulp. Spruces, like pines, form extensive
+forests. They are more frugal, thrive on thinner
+soils, and bear more shade, but usually require a more
+humid climate. "Black" and "White" spruce as applied
+by lumbermen usually refer to narrow and wide-ringed
+forms of black spruce (<i>Picea nigra</i>).</p>
+
+<p class="negative"><b>35. Black Spruce</b> (<i>Picea nigra</i> var. <i>mariana</i>). Medium-sized
+tree, forms extensive forests in northwestern
+United States and in British America; occurs scattered
+or in groves, especially in low lands throughout
+the northern pineries. Important lumber tree in
+eastern United States. Heartwood pale, often with
+reddish tinge; sapwood pure white. Wood light,<span class='pagenum'><a name="Page_28" id="Page_28">[28]</a></span>
+soft, not strong. Chiefly used for manufacture of
+paper pulp, and great quantities of this as well as
+<i>Picea alba</i> are used for this purpose. Used also for
+sounding boards for pianos, violins, etc. Maine to
+Minnesota, British America, and in the Alleghanies
+to North Carolina.</p>
+
+<p class="negative"><b>36. White Spruce</b> (<i>Picea canadensis</i> var. <i>alba</i>). Medium- to
+large-sized tree. Heartwood light yellow; sapwood
+nearly white. Generally associated with the
+preceding. Most abundant along streams and lakes,
+grows largest in Montana and forms the most important
+tree of the sub-arctic forest of British America.
+Used largely for floors, joists, doors, sashes, mouldings,
+and panel work, rapidly superceding <i>Pinus strobus</i>
+for building purposes. It is very similar to Norway
+pine, excels it in toughness, is rather less durable and
+dense, and more liable to warp in seasoning. Northern
+United States from Maine to Minnesota, also from
+Montana to Pacific, British America.</p>
+
+<p class="negative"><b>37. White Spruce</b> (<i>Picea engelmanni</i>). Medium- to large-sized
+tree, forming extensive forests at elevations
+from 5,000 to 10,000 feet above sea level; resembles
+the preceding, but occupies a different station. A
+very important timber tree in the central and southern
+parts of the Rocky Mountains. Rocky Mountains
+from Mexico to Montana.</p>
+
+<p class="negative"><b>38. Tide-Land Spruce</b> (<i>Picea sitchensis</i>) (Sitka Spruce).
+A large-sized tree, forming an extensive coast-belt
+forest. Used extensively for all classes of cooperage
+and woodenware on the Pacific Coast. Along the
+sea-coast from Alaska to central California.</p>
+
+<p class="negative"><b>39. Red Spruce</b> (<i>Picea rubens</i>). Medium-sized tree, generally
+associated with <i>Picea nigra</i> and occurs scattered
+throughout the northern pineries. Heartwood reddish;
+sapwood lighter color, straight-grained, compact
+structure. Wood light, soft, not strong, elastic,
+resonant, not durable when exposed. Used for flooring,
+carpentry, shipbuilding, piles, posts, railway<span class='pagenum'><a name="Page_29" id="Page_29">[29]</a></span>
+ties, paddles, oars, sounding boards, paper pulp, and
+musical instruments. Montana to Pacific, British
+America.</p>
+
+
+<h4>BASTARD SPRUCE</h4>
+
+<p>Spruce or fir in name, but resembling hard pine or larch
+in appearance, quality and uses of its wood.</p>
+
+<p class="negative"><b>40. Douglas Spruce</b> (<i>Pseudotsuga douglasii</i>) (Yellow Fir,
+Red Fir, Oregon Pine). One of the most important
+trees of the western United States; grows very large
+in the Pacific States, to fair size in all parts of the
+mountains, in Colorado up to about 10,000 feet above
+sea level; forms extensive forests, often of pure
+growth, it is really neither a pine nor a fir. Wood
+very variable, usually coarse-grained and heavy,
+with very pronounced summer-wood. Hard and
+strong ("red" fir), but often fine-grained and light
+("yellow" fir). It is the chief tree of Washington
+and Oregon, and most abundant and most valuable
+in British Columbia, where it attains its greatest
+size. From the plains to the Pacific Ocean, and from
+Mexico to British Columbia.</p>
+
+<p class="negative"><b>41. Red Fir</b> (<i>Pseudotsuga taxifolia</i>) (Oregon Pine, Puget
+Sound Pine, Yellow Fir, Douglas Spruce, Red Pine).
+Heartwood light red or yellow in color, sapwood narrow,
+nearly white, comparatively free from resins, variable
+annual rings. Wood usually hard, strong, difficult
+to work, durable, splinters easily. Used for heavy
+construction, dimension timber, railway ties, doors,
+blinds, interior finish, piles, etc. One of the most
+important of Western trees. From the plains to
+the Pacific Ocean, and from Mexico to British America.</p>
+
+
+<h4>TAMARACK (See Larch)</h4>
+
+<h4>YEW</h4>
+
+<p>Wood heavy, hard, extremely stiff and strong, of fine
+texture with a pale yellow sapwood, and an orange-red
+heartwood; seasons well and is quite durable. Extensively<span class='pagenum'><a name="Page_30" id="Page_30">[30]</a></span>
+used for archery bows, turner's ware, etc. The
+yews form no forests, but occur scattered with other
+conifers.</p>
+
+<p class="negative"><b>42. Yew</b> (<i>Taxus brevifolia</i>). A small to medium-sized
+tree of the Pacific region.</p>
+
+
+
+<h3 style="padding-bottom: 0em"><a name="SECTION_III" id="SECTION_III"></a>SECTION III<span class='pagenum'><a name="Page_31" id="Page_31">[31]</a></span></h3>
+
+<h2>BROAD-LEAVED TREES</h2>
+
+<h3 style="padding-top: 0em">WOOD OF BROAD-LEAVED TREES</h3>
+
+
+<div class="figright" style="width: 250px;"><p class="anchor"><a name="Fig_4" id="Fig_4"></a></p>
+<img src="images/fig04.jpg" width="250" height="260" alt="Block of Oak" title="Block of Oak" />
+
+<p class="caption">Fig. 4. Block of Oak. CS,
+cross-section; RS,
+radial section; TS, tangential
+section; <i>mr</i>,
+medullary or pith ray;
+<i>a</i>, height; <i>b</i>, width; and
+<i>e</i>, length of pith ray.</p>
+</div>
+
+<p><span class="smcap">On</span> a cross-section of oak, the same arrangement of pith
+and bark, of sapwood and heartwood, and the same disposition
+of the wood in well-defined concentric or annual
+rings occur, but the rings are marked by lines or rows of
+conspicuous pores or openings, which occupy the greater
+part of the spring-wood for each ring (see <a href="#Fig_4">Fig. 4</a>, also 6),
+and are, in fact the hollows of vessels
+through which the cut has been
+made. On the radial section or
+quarter-sawn board the several
+layers appear as so many stripes
+(see <a href="#Fig_5">Fig. 5</a>); on the tangential section
+or "bastard" face patterns
+similar to those mentioned for pine
+wood are observed. But while the
+patterns in hard pine are marked
+by the darker summer-wood, and
+are composed of plain, alternating
+stripes of darker and lighter wood,
+the figures in oak (and other broad-leaved
+woods) are due chiefly to
+the vessels, those of the spring-wood
+in oak being the most
+conspicuous (see <a href="#Fig_5">Fig. 5</a>). So that in an oak table, the
+darker, shaded parts are the spring-wood, the lighter
+unicolored parts the summer-wood. On closer examination
+of the smooth cross-section of oak, the spring-wood
+part of the ring is found to be formed in great part
+of pores; large, round, or oval openings made by the cut
+through long vessels. These are separated by a grayish<span class='pagenum'><a name="Page_32" id="Page_32">[32]</a></span>
+and quite porous tissue (see <a href="#Fig_6">Fig. 6</a>, A), which continues
+here and there in the form of radial, often branched,
+patches (not the pith rays) into and through the summer-wood
+to the spring-wood of the next ring. The large
+vessels of the spring-wood, occupying six to ten per cent
+of the volume of a log in very good oak, and twenty-five
+per cent or more in inferior and narrow-ringed timber,
+are a very important feature, since it is evident that the
+greater their share in the volume, the lighter and weaker
+the wood. They are smallest near the pith, and grow
+wider outward. They are wider in the stem than limb,
+and seem to be of indefinite length, forming open channels,
+in some cases probably as long
+as the tree itself. Scattered
+through the radiating gray
+patches of porous wood are
+vessels similar to those of the<span class='pagenum'><a name="Page_33" id="Page_33">[33]</a></span>
+spring-wood, but decidedly
+smaller. These vessels are
+usually fewer and larger near
+the outer portions of the ring.
+Their number and size can be
+utilized to distinguish the oaks
+classed as white oaks from
+those classed as black and
+red oaks. They are fewer and
+larger in red oaks, smaller but
+much more numerous in white
+oaks. The summer-wood,
+except for these radial, grayish patches, is dark colored and
+firm. This firm portion, divided into bodies or strands by
+these patches of porous wood, and also by fine, wavy, concentric
+lines of short, thin-walled cells (see <a href="#Fig_6">Fig. 6</a>, A), consists
+of thin-walled fibres (see <a href="#Fig_7">Fig. 7</a>, B), and is the chief element
+of strength in oak wood. In good white oak it forms
+one-half or more of the wood, if it cuts like horn, and the
+cut surface is shiny, and of a deep chocolate brown color.
+In very narrow-ringed wood and in inferior red oak it is
+usually much reduced in quantity as well as quality. The
+pith rays of the oak, unlike those of the coniferous woods,<span class='pagenum'><a name="Page_34" id="Page_34">[34]</a></span>
+are at least in part very large and conspicuous. (See <a href="#Fig_4">Fig.
+4</a>; their height indicated by the letter <i>a</i>, and their width
+by the letter <i>b</i>.) The large medullary rays of oak are
+often twenty and more cells wide, and several hundred
+cell rows in height, which amount
+commonly to one or more inches.
+These large rays are conspicuous
+on all sections. They appear as
+long, sharp, grayish lines on the
+cross-sections; as short, thick lines,
+tapering at each end, on the tangential
+or "bastard" face, and as
+broad, shiny bands, "the mirrors,"
+on the radial section. In addition
+to these coarse rays, there is also
+a large number of small pith rays,
+which can be seen only when magnified.
+On the whole, the pith
+rays form a much larger part of
+the wood than might be supposed.
+In specimens of good white oak it
+has been found that they form
+about sixteen to twenty-five per
+cent of the wood.</p>
+
+<div class="figcenter" style="width: 250px;"><p class="anchor"><a name="Fig_5" id="Fig_5"></a></p>
+<img src="images/fig05.jpg" width="250" height="364" alt="Board of Oak" title="Board of Oak" />
+
+<p class="caption">Fig. 5. Board of Oak. CS, cross-section; RS, radial section; TS, tangential
+section; <i>v</i>, vessels or pores, cut through.; A, slight curve in log which
+appears in section as an islet.</p>
+</div>
+
+<div class="figcenter" style="width: 400px; padding-top: 2em"><p class="anchor"><a name="Fig_6" id="Fig_6"></a></p>
+<img src="images/fig06.jpg" width="400" height="206" alt="Cross-section of Oak" title="Cross-section of Oak" />
+
+<p class="caption" style="margin-left: 4em">Fig. 6. Cross-section of Oak (Magnified about 5 times).</p>
+</div>
+
+<div class="figcenter" style="width: 250px; padding-top: 2em"><p class="anchor"><a name="Fig_7" id="Fig_7"></a></p>
+<img src="images/fig07.jpg" width="250" height="288" alt="Firm Bodies of Fibres" title="Firm Bodies of Fibres" />
+
+<p class="caption">Fig. 7. Portion of the Firm Bodies
+of Fibres with Two Cells of a
+Small Pith Ray <i>mr</i> (Highly
+Magnified).</p>
+</div>
+
+<div class="figcenter" style="width: 150px; padding-top: 2em"><p class="anchor"><a name="Fig_8" id="Fig_8"></a></p>
+<img src="images/fig08.jpg" width="150" height="386" alt="Isolated Fibres and Cells" title="Isolated Fibres and Cells" />
+</div>
+
+<p class="caption" style="width: 50%; margin-left: auto; margin-right: auto">Fig. 8. Isolated Fibres and
+Cells, <i>a</i>, four cells of
+wood, parenchyma; <i>b</i>,
+two cells from a pith ray;
+<i>c</i>, a single joint or cell of
+a vessel, the openings <i>x</i>
+leading into its upper
+and lower neighbors; <i>d</i>,
+tracheid; <i>e</i>, wood fibre
+proper.</p>
+
+<h4>Minute Structure</h4>
+
+<div class="figcenter" style="width: 400px;"><p class="anchor"><a name="Fig_9" id="Fig_9"></a></p>
+<img src="images/fig09.jpg" width="400" height="221" alt="Cross-section of Basswood" title="Cross-section of Basswood" />
+
+<p class="caption">Fig. 9. Cross-section of Basswood (Magnified). <i>v</i>, vessels; <i>mr</i>, pith rays.</p>
+</div>
+
+<p>If a well-smoothed thin disk or
+cross-section of oak (say one-sixteenth
+inch thick) is held up to
+the light, it looks very much like
+a sieve, the pores or vessels appearing
+as clean-cut holes. The
+spring-wood and gray patches are
+seen to be quite porous, but the
+firm bodies of fibres between them
+are dense and opaque. Examined
+with a magnifier it will be noticed
+that there is no such regularity of arrangement in straight
+rows as is conspicuous in pine. On the contrary, great
+irregularity prevails. At the same time, while the pores<span class='pagenum'><a name="Page_35" id="Page_35">[35]</a></span>
+are as large as pin holes, the cells of the denser wood,
+unlike those of pine wood, are too small to be distinguished.
+Studied with the microscope, each vessel is
+found to be a vertical row of a great number of short,
+wide tubes, joined end to end (see <a href="#Fig_8">Fig. 8</a>, <i>c</i>). The
+porous spring-wood and radial gray tracts are partly
+composed of smaller vessels, but chiefly of tracheids, like
+those of pine, and of shorter cells, the "wood parenchyma,"
+resembling the cells of the medullary rays. These latter,
+as well as the fine concentric lines mentioned as occurring
+in the summer-wood, are composed entirely of short tube-like
+parenchyma cells, with square or oblique ends (see
+<a href="#Fig_8">Fig. 8</a>, <i>a</i> and <i>b</i>). The wood fibres proper, which form the
+dark, firm bodies referred to, are very fine, thread-like
+cells, one twenty-fifth to one-tenth inch long, with a wall
+commonly so thick that scarcely any empty internal space
+or lumen remains (see <a href="#Fig_8">Figs. 8</a>, <i>e</i>, and <a href="#Fig_7">7</a>, B). If, instead
+of oak, a piece of poplar or basswood (see <a href="#Fig_9">Fig. 9</a>)
+had been used in this study, the structure would have
+been found to be quite different. The same kinds of cell-elements,
+vessels, etc., are, to be sure, present, but their
+combination and arrangement are different, and thus
+from the great variety of possible combinations results
+the great variety of structure and, in consequence, of
+the qualities which distinguish the wood of broad-leaved
+trees. The sharp distinction of sap wood and heartwood
+is wanting; the rings are not so clearly defined; the vessels<span class='pagenum'><a name="Page_36" id="Page_36">[36]</a></span>
+of the wood are small, very numerous, and rather evenly
+scattered through the wood of the annual rings, so that
+the distinction of the ring almost vanishes and the medullary
+or pith rays in poplar can be seen, without being
+magnified, only on the radial section.</p>
+
+
+<h3>LIST OF MOST IMPORTANT BROAD-LEAVED
+TREES (HARDWOODS)<span class='pagenum'><a name="Page_37" id="Page_37">[37]</a></span></h3>
+
+<p>Woods of complex and very variable structure, and
+therefore differing widely in quality, behavior, and consequently
+in applicability to the arts.</p>
+
+
+<h4>AILANTHUS</h4>
+
+<p class="negative"><b>1. Ailanthus</b> (<i>Ailanthus glandulosa</i>). Medium to large-sized
+tree. Wood pale yellow, hard, fine-grained, and
+satiny. This species originally came from China,
+where it is known as the Tree of "Heaven," was introduced
+into the United States and planted near
+Philadelphia during the 18th century, and is more
+ornamental than useful. It is used to some extent
+in cabinet work. Western Pennsylvania and Long
+Island, New York.</p>
+
+
+<h4>ASH</h4>
+
+<p>Wood heavy, hard, stiff, quite tough, not durable in
+contact with the soil, straight-grained, rough on the split
+surfaces and coarse in texture. The wood shrinks moderately,
+seasons with little injury, stands well, and takes a
+good polish. In carpentry, ash is used for stairways,
+panels, etc. It is used in shipbuilding, in the construction
+of cars, wagons, etc., in the manufacture of all kinds of
+farm implements, machinery, and especially of all kinds
+of furniture; for cooperage, baskets, oars, tool handles,
+hoops, etc., etc. The trees of the several species of ash
+are rapid growers, of small to medium height with stout
+trunks. They form no forests, but occur scattered in
+almost all our broad-leaved forests.</p>
+
+<p class="negative"><b>2. White Ash</b> (<i>Fraxinus Americana</i>). Medium-, sometimes
+large-sized tree. Heartwood reddish brown,
+usually mottled; sapwood lighter color, nearly white.
+Wood heavy, hard, tough, elastic, coarse-grained,<span class='pagenum'><a name="Page_38" id="Page_38">[38]</a></span>
+compact structure. Annual rings clearly marked by
+large open pores, not durable in contact with the
+soil, is straight-grained, and the best material for oars,
+etc. Used for agricultural implements, tool handles,
+automobile (rim boards), vehicle bodies and parts,
+baseball bats, interior finish, cabinet work, etc., etc.
+Basin of the Ohio, but found from Maine to Minnesota
+and Texas.</p>
+
+<p class="negative"><b>3. Red Ash</b> (<i>Fraxinus pubescens</i> var. <i>Pennsylvanica</i>).
+Medium-sized tree, a timber very similar to, but
+smaller than <i>Fraxinus Americana</i>. Heartwood light
+brown, sapwood lighter color. Wood heavy, hard,
+strong, and coarse-grained. Ranges from New
+Brunswick to Florida, and westward to Dakota,
+Nebraska, and Kansas.</p>
+
+<p class="negative"><b>4. Black Ash</b> (<i>Fraxinus nigra</i> var. <i>sambucifolia</i>) (Hoop
+Ash, Ground Ash). Medium-sized tree, very common,
+is more widely distributed than the <i>Fraxinus Americana</i>;
+the wood is not so hard, but is well suited for
+hoops and basketwork. Heartwood dark brown,
+sapwood light brown or white. Wood heavy, rather
+soft, tough and coarse-grained. Used for barrel
+hoops, basketwork, cabinetwork and interior of
+houses. Maine to Minnesota and southward to
+Alabama.</p>
+
+<p class="negative"><b>5. Blue Ash</b> (<i>Fraxinus quadrangulata</i>). Small to medium-sized
+tree. Heartwood yellow, streaked with brown,
+sapwood a lighter color. Wood heavy, hard, and
+coarse-grained. Not common. Indiana and Illinois;
+occurs from Michigan to Minnesota and southward
+to Alabama.</p>
+
+<p class="negative"><b>6. Green Ash</b> (<i>Fraxinus viridis</i>). Small-sized tree. Occurs
+from New York to the Rocky Mountains, and
+southward to Florida and Arizona.</p>
+
+<p class="negative"><b>7. Oregon Ash</b> (<i>Fraxinus Oregana</i>). Small to medium-sized
+tree. Occurs from western Washington to
+California.<span class='pagenum'><a name="Page_39" id="Page_39">[39]</a></span></p>
+
+<p class="negative"><b>8. Carolina Ash</b> (<i>Fraxinus Caroliniana</i>). Medium-sized
+tree. Occurs in the Carolinas and the coast regions
+southward.</p>
+
+
+<h4>ASPEN (See Poplar)</h4>
+
+
+<h4>BASSWOOD</h4>
+
+<p class="negative"><b>9. Basswood</b> (<i>Tilia Americana</i>) (Linden, Lime Tree,
+American Linden, Lin, Bee Tree). Medium- to large-sized
+tree. Wood light, soft, stiff, but not strong,
+of fine texture, straight and close-grained, and white
+to light brown color, but not durable in contact with
+the soil. The wood shrinks considerably in drying,
+works well and stands well in interior work. It is
+used for cooperage, in carpentry, in the manufacture
+of furniture and woodenware (both turned and carved),
+for toys, also for panelling of car and carriage bodies,
+for agricultural implements, automobiles, sides and
+backs of drawers, cigar boxes, excelsior, refrigerators,
+trunks, and paper pulp. It is also largely cut for
+veneer and used as "three-ply" for boxes and chair
+seats. It is used for sounding boards in pianos and
+organs. If well seasoned and painted it stands fairly
+well for outside work. Common in all northern
+broad-leaved forests. Found throughout the eastern
+United States, but reaches its greatest size in the
+Valley of the Ohio, becoming often 130 feet in height,
+but its usual height is about 70 feet.</p>
+
+<p class="negative"><b>10. White Basswood</b> (<i>Tilia heterophylla</i>) (Whitewood).
+A small-sized tree. Wood in its quality and uses
+similar to the preceding, only it is lighter in color.
+Most abundant in the Alleghany region.</p>
+
+<p class="negative"><b>11. White Basswood</b> (<i>Tilia pubescens</i>) (Downy Linden,
+Small-leaved Basswood). Small-sized tree. Wood
+in its quality and uses similar to <i>Tilia Americana</i>.
+This is a Southern species which makes it way as far
+north as Long Island. Is found at its best in South
+Carolina.<span class='pagenum'><a name="Page_40" id="Page_40">[40]</a></span></p>
+
+
+<h4>BEECH</h4>
+
+<p class="negative"><b>12. Beech</b> (<i>Fagus ferruginea</i>) (Red Beech, White Beech).
+Medium-sized tree, common, sometimes forming
+forests of pure growth. Wood heavy, hard, stiff,
+strong, of rather coarse texture, white to light brown
+color, not durable in contact with the soil, and subject
+to the inroads of boring insects. Rather close-grained,
+conspicuous medullary rays, and when
+quarter-sawn and well smoothed is very beautiful.
+The wood shrinks and checks considerably in drying,
+works well and stands well, and takes a fine polish.
+Beech is comparatively free from objectionable taste,
+and finds a place in the manufacture of commodities
+which come in contact with foodstuffs, such as lard
+tubs, butter boxes and pails, and the beaters of ice
+cream freezers; for the latter the persistent hardness
+of the wood when subjected to attrition and abrasion,
+while wet gives it peculiar fitness. It is an excellent
+material for churns. Sugar hogsheads are made of
+beech, partly because it is a tasteless wood and partly
+because it has great strength. A large class of woodenware,
+including veneer plates, dishes, boxes, paddles,
+scoops, spoons, and beaters, which belong to the
+kitchen and pantry, are made of this species of wood.
+Beech picnic plates are made by the million, a single
+machine turning out 75,000 a day. The wood has
+a long list of miscellaneous uses and enters in
+a great variety of commodities. In every region
+where it grows in commercial quantities it is made
+into boxes, baskets, and crating. Beech baskets are
+chiefly employed in shipping fruit, berries, and vegetables.
+In Maine thin veneer of beech is made
+specially for the Sicily orange and lemon trade. This
+is shipped in bulk and the boxes are made abroad.
+Beech is also an important handle wood, although
+not in the same class with hickory. It is not selected
+because of toughness and resiliency, as hickory is,
+and generally goes into plane, handsaw, pail, chisel,<span class='pagenum'><a name="Page_41" id="Page_41">[41]</a></span>
+and flatiron handles. Recent statistics show that
+in the production of slack cooperage staves, only
+two woods, red gum and pine, stood above beech in
+quantity, while for heading, pine alone exceeded it.
+It is also used in turnery, for shoe lasts, butcher
+blocks, ladder rounds, etc. Abroad it is very extensively
+used by the carpenter, millwright, and wagon
+maker, in turnery and wood carving. Most abundant
+in the Ohio and Mississippi basin, but found from
+Maine to Wisconsin and southward to Florida.</p>
+
+
+<h4>BIRCH</h4>
+
+<p class="negative"><b>13. Cherry Birch</b> (<i>Betula lenta</i>) (Black Birch, Sweet Birch,
+Mahogany Birch, Wintergreen Birch). Medium-sized
+tree, very common. Wood of beautiful reddish
+or yellowish brown, and much of it nicely figured,
+of compact structure, is straight in grain, heavy,
+hard, strong, takes a fine polish, and considerably used
+as imitation of mahogany. The wood shrinks considerably
+in drying, works well and stands well, but
+is not durable in contact with the soil. The medullary
+rays in birch are very fine and close and not
+easily seen. The sweet birch is very handsome, with
+satiny luster, equalling cherry, and is too costly a
+wood to be profitably used for ordinary purposes,
+but there are both high and low grades of birch, the
+latter consisting chiefly of sapwood and pieces too
+knotty for first class commodities. This cheap material
+swells the supply of box lumber, and a little of
+it is found wherever birch passes through sawmills.
+The frequent objections against sweet birch as box
+lumber and crating material are that it is hard to
+nail and is inclined to split. It is also used for veneer
+picnic plates and butter dishes, although it is not
+as popular for this class of commodity as are yellow
+and paper birch, maple and beech. The best grades
+are largely used for furniture and cabinet work, and
+also for interior finish. Maine to Michigan and to
+Tennessee.<span class='pagenum'><a name="Page_42" id="Page_42">[42]</a></span></p>
+
+<p class="negative"><b>14. White Birch</b> (<i>Betula populifolia</i>) (Gray Birch, Old
+Field Birch, Aspen-leaved Birch). Small to medium-sized
+tree, least common of all the birches. Short-lived,
+twenty to thirty feet high, grows very rapidly.
+Heartwood light brown, sapwood lighter color. Wood
+light, soft, close-grained, not strong, checks badly
+in drying, decays quickly, not durable in contact
+with the soil, takes a good polish. Used for spools,
+shoepegs, wood pulp, and barrel hoops. Fuel, value
+not high, but burns with bright flame. Ranges from
+Nova Scotia and lower St. Lawrence River, southward,
+mostly in the coast region to Delaware, and
+westward through northern New England and New
+York to southern shore of Lake Ontario.</p>
+
+<p class="negative"><b>15. Yellow Birch</b> (<i>Betula lutea</i>) (Gray Birch, Silver Birch).
+Medium- to large-sized tree, very common. Heartwood
+light reddish brown, sapwood nearly white,
+close-grained, compact structure, with a satiny luster.
+Wood heavy, very strong, hard, tough, susceptible
+of high polish, not durable when exposed. Is similar
+to <i>Betula lenta</i>, and finds a place in practically all
+kinds of woodenware. A large percentage of broom
+handles on the market are made of this species of
+wood, though nearly every other birch contributes
+something. It is used for veneer plates and dishes
+made for pies, butter, lard, and many other commodities.
+Tubs and pails are sometimes made of
+yellow birch provided weight is not objectionable.
+The wood is twice as heavy as some of the pines and
+cedars. Many small handles for such articles as
+flatirons, gimlets, augers, screw drivers, chisels, varnish
+and paint brushes, butcher and carving knives,
+etc. It is also widely used for shipping boxes, baskets,
+and crates, and it is one of the stiffest, strongest
+woods procurable, but on account of its excessive
+weight it is sometimes discriminated against. It
+is excellent for veneer boxes, and that is probably
+one of the most important places it fills. Citrus
+fruit from northern Africa and the islands and countries
+of the Mediterranean is often shipped to market<span class='pagenum'><a name="Page_43" id="Page_43">[43]</a></span>
+in boxes made of yellow birch from veneer cut in
+New England. The better grades are also used for
+furniture and cabinet work, and the "burls" found
+on this species are highly valued for making fancy
+articles, gavels, etc. It is extensively used for turnery,
+buttons, spools, bobbins, wheel hubs, etc. Maine
+to Minnesota and southward to Tennessee.</p>
+
+<p class="negative"><b>16. Red Birch</b> (<i>Betula rubra</i> var. <i>nigra</i>) (River Birch).
+Small to medium-sized tree, very common. Lighter
+and less valuable than the preceding. Heartwood
+light brown, sapwood pale. Wood light, fairly strong
+and close-grained. Red birch is best developed in
+the middle South, and usually grows near the banks
+of rivers. Its bark hangs in tatters, even worse than
+that of paper birch, but it is darker. In Tennessee
+the slack coopers have found that red birch makes
+excellent barrel heads and it is sometimes employed
+in preference to other woods. In eastern Maryland
+the manufacturers of peach baskets draw their supplies
+from this wood, and substitute it for white elm
+in making the hoops or bands which stiffen the top
+of the basket, and provide a fastening for the veneer
+which forms the sides. Red birch bends in a very
+satisfactory manner, which is an important point.
+This wood enters pretty generally into the manufacture
+of woodenware within its range, but statistics
+do not mention it by name. It is also used in the
+manufacture of veneer picnic plates, pie plates, butter
+dishes, washboards, small handles, kitchen and pantry
+utensils, and ironing boards. New England to Texas
+and Missouri.</p>
+
+<p class="negative"><b>17. Canoe Birch</b> (<i>Betula paprifera</i>) (White Birch, Paper
+Birch). Small to medium-sized tree, sometimes forming
+forests, very common. Heartwood light brown
+tinged with red, sapwood lighter color. Wood of
+good quality, but light, fairly hard and strong, tough,
+close-grained. Sap flows freely in spring and by
+boiling can be made into syrup. Not as valuable as
+any of the preceding. Canoe birch is a northern<span class='pagenum'><a name="Page_44" id="Page_44">[44]</a></span>
+tree, easily identified by its white trunk and its ragged
+bark. Large numbers of small wooden boxes are
+made by boring out blocks of this wood, shaping
+them in lathes, and fitting lids on them. Canoe
+birch is one of the best woods for this class of commodities,
+because it can be worked very thin, does
+not split readily, and is of pleasing color. Such boxes,
+or two-piece diminutive kegs, are used as containers
+for articles shipped and sold in small bulk, such as
+tacks, small nails, and brads. Such containers are
+generally cylindrical and of considerably greater depth
+than diameter. Many others of nearly similar form
+are made to contain ink bottles, bottles of perfumery,
+drugs, liquids, salves, lotions, and powders of many
+kinds. Many boxes of this pattern are used by
+manufacturers of pencils and crayons for packing
+and shipping their wares. Such boxes are made in
+numerous numbers by automatic machinery. A
+single machine of the most improved pattern will
+turn out 1,400 boxes an hour. After the boring and
+turning are done, they are smoothed by placing them
+into a tumbling barrel with soapstone. It is also
+used for one-piece shallow trays or boxes, without
+lids, and used as card receivers, pin receptacles,
+butter boxes, fruit platters, and contribution plates
+in churches. It is also the principal wood used for
+spools, bobbins, bowls, shoe lasts, pegs, and turnery,
+and is also much used in the furniture trade. All
+along the northern boundary of the United States
+and northward, from the Atlantic to the Pacific.</p>
+
+
+<h4>BLACK WALNUT (See Walnut)</h4>
+
+<h4>BLUE BEECH</h4>
+
+<p class="negative"><b>18. Blue Beech</b> (<i>Carpinus Caroliniana</i>) (Hornbeam, Water
+Beech, Ironwood). Small-sized tree. Heartwood
+light brown, sapwood nearly white. Wood very hard,
+heavy, strong, very stiff, of rather fine texture, not
+durable in contact with the soil, shrinks and checks
+considerably in drying, but works well and stands<span class='pagenum'><a name="Page_45" id="Page_45">[45]</a></span>
+well, and takes a fine polish. Used chiefly in turnery,
+for tool handles, etc. Abroad much used by mill-
+and wheelwrights. A small tree, largest in the Southwest,
+but found in nearly all parts of the eastern
+United States.</p>
+
+
+<h4>BOIS D'ARC (See Osage Orange)</h4>
+
+
+<h4>BUCKEYE</h4>
+
+<p>Wood light, soft, not strong, often quite tough, of fine,
+uniform texture and creamy white color. It shrinks considerably
+in drying, but works well and stands well. Used
+for woodenware, artificial limbs, paper pulp, and locally
+also for building construction.</p>
+
+<p class="negative"><b>19. Ohio Buckeye</b> (<i>&AElig;sculus glabra</i>) (Horse Chestnut,
+Fetid Buckeye). Small-sized tree, scattered, never
+forming forests. Heartwood white, sapwood pale
+brown. Wood light, soft, not strong, often quite
+tough and close-grained. Alleghanies, Pennsylvania
+to Oklahoma.</p>
+
+<p class="negative"><b>20. Sweet Buckeye</b> (<i>&AElig;sculus octandra</i> var. <i>flava</i>) (Horse
+Chestnut). Small-sized tree, scattered, never forming
+forests. Wood in its quality and uses similar to
+the preceding. Alleghanies, Pennsylvania to Texas.</p>
+
+
+<h4>BUCKTHORNE</h4>
+
+<p class="negative"><b>21. Buckthorne</b> (<i>Rhanmus Caroliniana</i>) (Indian Cherry).
+Small-sized tree. Heartwood light brown, sapwood
+almost white. Wood light, hard, close-grained. Does
+not enter the markets to any great extent. Found
+along the borders of streams in rich bottom lands.
+Its northern limits is Long Island, where it is only
+a shrub; it becomes a tree only in southern Arkansas
+and adjoining regions.</p>
+
+
+<h4>BUTTERNUT</h4>
+
+<p class="negative"><b>22. Butternut</b> (<i>Juglans cinerea</i>) (White Walnut, White
+Mahogany, Walnut). Medium-sized tree, scattered,<span class='pagenum'><a name="Page_46" id="Page_46">[46]</a></span>
+never forming forests. Wood very similar to black
+walnut, but light, quite soft, and not strong. Heartwood
+light gray-brown, darkening with exposure;
+sapwood nearly white, coarse-grained, compact structure,
+easily worked, and susceptible to high polish.
+Has similar grain to black walnut and when stained
+is a very good imitation. Is much used for inside
+work, and very durable. Used chiefly for finishing
+lumber, cabinet work, boat finish and fixtures, and
+for furniture. Butternut furniture is often sold as
+circassian walnut. Largest and most common in the
+Ohio basin. Maine to Minnesota and southward
+to Georgia and Alabama.</p>
+
+
+<h4>CATALPA</h4>
+
+<p>The catalpa is a tree which was planted about 25 years
+ago as a commercial speculation in Iowa, Kansas, and
+Nebraska. Its native habitat was along the rivers Ohio
+and lower Wabash, and a century ago it gained a reputation
+for rapid growth and durability, but did not grow
+in large quantities. As a railway tie, experiments have
+left no doubt as to its resistance to decay; it stands abrasion
+as well as the white oak (<i>Quercus alba</i>), and is
+superior to it in longevity. Catalpa is a tree singularly
+free from destructive diseases. Wood cut from the living
+tree is one of the most durable timbers known. In spite
+of its light porous structure it resists the weathering influences
+and the attacks of wood-destroying fungi to a
+remarkable degree. No fungus has yet been found which
+will grow in the dead timber, and for fence posts this wood
+has no equal, lasting longer than almost any other species
+of timber. The wood is rather soft and coarse in texture,
+the tree is of slow growth, and the brown colored heartwood,
+even of very young trees, forms nearly three-quarters of
+their volume. There is only about one-quarter inch of
+sapwood in a 9-inch tree.</p>
+
+<p class="negative"><b>23. Catalpa</b> (<i>Catalpa speciosa</i> var. <i>bignonioides</i>) (Indian
+Bean). Medium-sized tree. Heartwood light brown,
+sapwood nearly white. Wood light, soft, not strong,<span class='pagenum'><a name="Page_47" id="Page_47">[47]</a></span>
+brittle, very durable in contact with the soil, of coarse
+texture. Used chiefly for railway ties, telegraph poles,
+and fence posts, but well suited for a great variety of
+uses. Lower basin of the Ohio River, locally common.
+Extensively planted, and therefore promising
+to become of some importance.</p>
+
+
+<h4>CHERRY</h4>
+
+<p class="negative"><b>24. Cherry</b> (<i>Prunus serotina</i>) (Wild Cherry, Black Cherry,
+Rum Cherry). Wood heavy, hard, strong, of fine
+texture. Sapwood yellowish white, heartwood reddish
+to brown. The wood shrinks considerably in drying,
+works well and stands well, has a fine satin-like luster,
+and takes a fine polish which somewhat resembles
+mahogany, and is much esteemed for its beauty.
+Cherry is chiefly used as a decorative interior finishing
+lumber, for buildings, cars and boats, also for
+furniture and in turnery, for musical instruments,
+walking sticks, last blocks, and woodenware. It is
+becoming too costly for many purposes for which it
+is naturally well suited. The lumber-furnishing
+cherry of the United States, the wild black cherry,
+is a small to medium-sized tree, scattered through
+many of the broad-leaved trees of the western slope
+of the Alleghanies, but found from Michigan to
+Florida, and west to Texas. Other species of this
+genus, as well as the hawthornes (<i>Prunus cratoegus</i>)
+and wild apple (<i>Pyrus</i>), are not commonly offered in
+the markets. Their wood is of the same character
+as cherry, often finer, but in smaller dimensions.</p>
+
+<p class="negative"><b>25. Red Cherry</b> (<i>Prunus Pennsylvanica</i>) (Wild Red Cherry,
+Bird Cherry). Small-sized tree. Heartwood light
+brown, sapwood pale yellow. Wood light, soft, and
+close-grained. Uses similiar to the preceding, common
+throughout the Northern States, reaching its
+greatest size on the mountains of Tennessee.<span class='pagenum'><a name="Page_48" id="Page_48">[48]</a></span></p>
+
+
+<h4>CHESTNUT</h4>
+
+<p>The chestnut is a long-lived tree, attaining an age of
+from 400 to 600 years, but trees over 100 years are usually
+hollow. It grows quickly, and sprouts from a chestnut
+stump (Coppice Chestnut) often attain a height of 8 feet
+in the first year. It has a fairly cylindrical stem, and
+often grows to a height of 100 feet and over. Coppice
+chestnut, that is, chestnut grown on an old stump, furnishes
+better timber for working than chestnut grown from the
+nut, it is heavier, less spongy, straighter in grain, easier
+to split, and stands exposure longer.</p>
+
+<p class="negative"><b>26. Chestnut</b> (<i>Castanea vulgaris</i> var. <i>Americana</i>). Medium-
+to large-sized tree, never forming forests. Wood
+is light, moderately hard, stiff, elastic, not strong,
+but very durable when in contact with the soil, of
+coarse texture. Sapwood light, heartwood darker
+brown, and is readily distinguishable from the sapwood,
+which very early turns into heartwood. It
+shrinks and checks considerably in drying, works
+easily, stands well. The annual rings are very distinct,
+medullary rays very minute and not visible to
+the naked eye. Used in cooperage, for cabinetwork,
+agricultural implements, railway ties, telegraph poles,
+fence posts, sills, boxes, crates, coffins, furniture,
+fixtures, foundation for veneer, and locally in heavy
+construction. Very common in the Alleghanies. Occurs
+from Maine to Michigan and southward to
+Alabama.</p>
+
+<p class="negative"><b>27. Chestnut</b> (<i>Castanea dentata</i> var. <i>vesca</i>). Medium-sized
+tree, never forming forests, not common.
+Heartwood brown color, sapwood lighter shade,
+coarse-grained. Wood and uses similar to the preceding.
+Occurs scattered along the St. Lawrence River,
+and even there is met with only in small quantities.</p>
+
+<p class="negative"><b>28. Chinquapin</b> (<i>Castanea pumila</i>). Medium- to small-sized
+tree, with wood slightly heavier, but otherwise
+similiar to the preceding. Most common in Arkansas,
+but with nearly the same range as <i>Castanea vulgaris</i>.<span class='pagenum'><a name="Page_49" id="Page_49">[49]</a></span></p>
+
+<p class="negative"><b>29. Chinquapin</b> (<i>Castanea chrysophylla</i>). A medium-sized
+tree of the western ranges of California and Oregon.</p>
+
+
+<h4>COFFEE TREE</h4>
+
+<p class="negative"><b>30. Coffee Tree</b> (<i>Gymnocladus dioicus</i>) (Coffee Nut,
+Stump Tree). A medium- to large-sized tree, not
+common. Wood heavy, hard, strong, very stiff, of
+coarse texture, and durable. Sapwood yellow, heartwood
+reddish brown, shrinks and checks considerably
+in drying, works well and stands well, and takes a
+fine polish. It is used to a limited extent in cabinetwork
+and interior finish. Pennsylvania to Minnesota
+and Arkansas.</p>
+
+
+<h4>COTTONWOOD (See Poplar)</h4>
+
+<h4>CRAB APPLE</h4>
+
+<p class="negative"><b>31. Crab Apple</b> (<i>Pyrus coronaria</i>) (Wild Apple, Fragrant
+Crab). Small-sized tree. Heartwood reddish brown,
+sapwood yellow. Wood heavy, hard, not strong,
+close-grained. Used principally for tool handles and
+small domestic articles. Most abundant in the middle
+and western states, reaches its greatest size in the
+valleys of the lower Ohio basin.</p>
+
+
+<h4>CUCUMBER TREE (See Magnolia)</h4>
+
+<h4>DOGWOOD</h4>
+
+<p class="negative"><b>32. Dogwood</b> (<i>Cornus florida</i>) (American Box). Small to
+medium-sized tree. Attains a height of about 30
+feet and about 12 inches in diameter. The heartwood
+is a red or pinkish color, the sapwood, which is
+considerable, is a creamy white. The wood has a
+dull surface and very fine grain. It is valuable for
+turnery, tool handles, and mallets, and being so free
+from silex, watchmakers use small splinters of it for
+cleaning out the pivot holes of watches, and opticians
+for removing dust from deep-seated lenses. It is<span class='pagenum'><a name="Page_50" id="Page_50">[50]</a></span>
+also used for butchers' skewers, and shuttle blocks
+and wheel stock, and is suitable for turnery and inlaid
+work. Occurs scattered in all the broad-leaved forests
+of our country; very common.</p>
+
+
+<h4>ELM</h4>
+
+<p>Wood heavy, hard, strong, elastic, very tough, moderately
+durable in contact with the soil, commonly cross-grained,
+difficult to split and shape, warps and checks
+considerably in drying, but stands well if properly seasoned.
+The broad sapwood whitish, heartwood light brown, both
+with shades of gray and red. On split surfaces rough,
+texture coarse to fine, capable of high polish. Elm for
+years has been the principal wood used in slack cooperage
+for barrel staves, also in the construction of cars, wagons,
+etc., in boat building, agricultural implements and machinery,
+in saddlery and harness work, and particularly
+in the manufacture of all kinds of furniture, where
+the beautiful figures, especially those of the tangential or
+bastard section, are just beginning to be appreciated.
+The elms are medium- to large-sized trees, of fairly rapid
+growth, with stout trunks; they form no forests of pure
+growth, but are found scattered in all the broad-leaved
+woods of our country, sometimes forming a considerable
+portion of the arborescent growth.</p>
+
+<p class="negative"><b>33. White Elm</b> (<i>Ulmus Americana</i>) (American Elm, Water
+Elm). Medium- to large-sized tree. Wood in its
+quality and uses as stated above. Common. Maine
+to Minnesota, southward to Florida and Texas.</p>
+
+<p class="negative"><b>34. Rock Elm</b> (<i>Ulmus racemosa</i>) (Cork Elm, Hickory Elm,
+White Elm, Cliff Elm). Medium- to large-sized tree
+of rapid growth. Heartwood light brown, often
+tinged with red, sapwood yellowish or greenish white,
+compact structure, fibres interlaced. Wood heavy,
+hard, very tough, strong, elastic, difficult to split,
+takes a fine polish. Used for agricultural implements,
+automobiles, crating, boxes, cooperage, tool
+handles, wheel stock, bridge timbers, sills, interior<span class='pagenum'><a name="Page_51" id="Page_51">[51]</a></span>
+finish, and maul heads. Fairly free from knots and
+has only a small quantity of sapwood. Michigan,
+Ohio, from Vermont to Iowa, and southward to
+Kentucky.</p>
+
+<p class="negative"><b>35. Red Elm</b> (<i>Ulmus fulva</i> var. <i>pubescens</i>) (Slippery Elm,
+Moose Elm). The red or slippery elm is not as large
+a tree as the white elm (<i>Ulmus Americana</i>), though
+it occasionally attains a height of 135 feet and a diameter
+of 4 feet. It grows tall and straight, and
+thrives in river valleys. The wood is heavy, hard,
+strong, tough, elastic, commonly cross-grained, moderately
+durable in contact with the soil, splits easily
+when green, works fairly well, and stands well if
+properly handled. Careful seasoning and handling
+are essential for the best results. Trees can be
+utilized for posts when very small. When green the
+wood rots very quickly in contact with the soil.
+Poles for posts should be cut in summer and peeled
+and dried before setting. The wood becomes very
+tough and pliable when steamed, and is of value for
+sleigh runners and for ribs of canoes and skiffs. Together
+with white elm (<i>Ulmus Americana</i>) it is extensively
+used for barrel staves in slack cooperage
+and also for furniture. The thick, viscous inner
+bark, which gives the tree its descriptive name, is
+quite palatable, slightly nutritious, and has a medicinal
+value. Found chiefly along water courses.
+New York to Minnesota, and southward to Florida
+and Texas.</p>
+
+<p class="negative"><b>36. Cedar Elm</b> (<i>Ulmus crassifolia</i>). Medium- to small-sized
+tree, locally quite common. Arkansas and
+Texas.</p>
+
+<p class="negative"><b>37. Winged Elm</b> (<i>Ulmus alata</i>) (Wahoo). Small-sized
+tree, locally quite common. Heartwood light brown,
+sapwood yellowish white. Wood heavy, hard, tough,
+strong, and close-grained. Arkansas, Missouri, and
+eastern Virginia.<span class='pagenum'><a name="Page_52" id="Page_52">[52]</a></span></p>
+
+<div class="figcenter" style="width: 400px; padding-top: 2em"><p class="anchor"><a name="Fig_10" id="Fig_10"></a></p>
+<img src="images/fig10.jpg" width="400" height="491" alt="A Large Red Gum" title="A Large Red Gum" />
+
+<p class="caption" style="text-align: center">Fig. 10. A Large Red Gum.</p>
+</div>
+
+
+<h4>GUM</h4>
+
+<p>This general term applies to three important species
+of gum in the South, the principal one usually being distinguished
+as "red" or "sweet" gum (see <a href="#Fig_10">Fig. 10</a>).
+The next in importance being the "tupelo" or "bay poplar,"
+and the least of the trio is designated as "black" or
+"sour" gum (see <a href="#Fig_11">Fig. 11</a>). Up to the year 1900 little
+was known of gum as a wood for cooperage purposes, but<span class='pagenum'><a name="Page_53" id="Page_53">[53]</a></span>
+by the continued advance in price of the woods used, a
+few of the most progressive manufacturers, looking into
+the future, saw that the supply of the various woods in
+use was limited, that new woods would have to be sought,
+and gum was looked upon as a possible substitute, owing
+to its cheapness and abundant supply. No doubt in the
+future this wood will be used to a considerable extent in
+the manufacture of both "tight" and "slack" cooperage.<span class='pagenum'><a name="Page_54" id="Page_54">[54]</a></span>
+In the manufacture of the gum, unless the knives and
+saws are kept very sharp, the wood has a tendency to
+break out, the corners splitting off; and also, much difficulty
+has been experienced in seasoning and kiln-drying.</p>
+
+<div class="figcenter" style="width: 400px; padding-top: 2em"><p class="anchor"><a name="Fig_11" id="Fig_11"></a></p>
+<img src="images/fig11.jpg" width="400" height="504" alt="A Tupelo Gum Slough" title="A Tupelo Gum Slough" />
+
+<p class="caption" style="text-align: center">Fig. 11. A Tupelo Gum Slough.</p>
+</div>
+
+<p>In the past, gum, having no marketable value, has been
+left standing after logging operations, or, where the land
+has been cleared for farming, the trees have been "girdled"
+and allowed to rot, and then felled and burned as trash.
+Now, however, that there is a market for this species of
+timber, it will be profitable to cut the gum with the other
+hardwoods, and this species of wood will come in for a
+greater share of attention than ever before.</p>
+
+<p class="negative"><b>38. Red Gum</b> (<i>Liquidamber styraciflua</i>) (Sweet Gum,
+Hazel Pine, Satin Walnut, Liquidamber, Bilsted).
+The wood is about as stiff and as strong as chestnut,
+rather heavy, it splits easily and is quite brash, commonly
+cross-grained, of fine texture, and has a large
+proportion of whitish sapwood, which decays rapidly
+when exposed to the weather; but the reddish brown
+heartwood is quite durable, even in the ground. The
+external appearance of the wood is of fine grain and
+smooth, close texture, but when broken the lines of
+fracture do not run with apparent direction of the
+growth; possibly it is this unevenness of grain which
+renders the wood so difficult to dry without twisting
+and warping. It has little resiliency; can be easily
+bent when steamed, and when properly dried will
+hold its shape. The annual rings are not distinctly
+marked, medullary rays fine and numerous. The
+green wood contains much water, and consequently is
+heavy and difficult to float, but when dry it is as light
+as basswood. The great amount of water in the
+green wood, particularly in the sap, makes it difficult
+to season by ordinary methods without warping and
+twisting. It does not check badly, is tasteless and
+odorless, and when once seasoned, swells and shrinks
+but little unless exposed to the weather. Used for
+boat finish, veneers, cabinet work, furniture, fixtures,
+interior decoration, shingles, paving blocks, woodenware,<span class='pagenum'><a name="Page_55" id="Page_55">[55]</a></span>
+cooperage, machinery frames, refrigerators, and
+trunk slats.</p>
+
+
+<h4>Range of Red Gum</h4>
+
+<p>Red gum is distributed from Fairfield County, Conn.,
+to southeastern Missouri, through Arkansas and Oklahoma
+to the valley of the Trinity River in Texas,
+and eastward to the Atlantic coast. Its commercial
+range is restricted, however, to the moist lands of
+the lower Ohio and Mississippi basins and of the Southeastern
+coast. It is one of the commonest timber trees
+in the hardwood bottoms and drier swamps of the South.
+It grows in mixture with ash, cottonwood and oak (see
+<a href="#Fig_12">Fig. 12</a>). It is also found to a considerable extent on
+the lower ridges and slopes of the southern Appalachians,
+but there it does not reach merchantable value and is of
+little importance. Considerable difference is found between
+the growth in the upper Mississippi bottoms and
+that along the rivers on the Atlantic coast and on the
+Gulf. In the latter regions the bottoms are lower, and
+consequently more subject to floods and to continued
+overflows (see <a href="#Fig_11">Fig. 11</a>). The alluvial deposit is also greater,
+and the trees grow considerably faster. Trees of the same
+diameter show a larger percentage of sapwood there than
+in the upper portions of the Mississippi Valley. The
+Mississippi Valley hardwood trees are for the most part
+considerably older, and reach larger dimensions than the
+timber along the coast.</p>
+
+
+<h4>Form of the Red Gum</h4>
+
+<p>In the best situations red gum reaches a height of 150
+feet, and a diameter of 5 feet. These dimensions, however
+are unusual. The stem is straight and cylindrical,
+with dark, deeply-furrowed bark, and branches often
+winged with corky ridges. In youth, while growing vigorously
+under normal conditions, it assumes a long, regular,
+conical crown, much resembling the form of a conifer
+(see <a href="#Fig_12">Fig. 12</a>). After the tree has attained its height
+growth, however, the crown becomes rounded, spreading
+and rather ovate in shape. When growing in the forest<span class='pagenum'><a name="Page_56" id="Page_56">[56]</a></span>
+the tree prunes itself readily at an early period, and forms
+a good length of clear stem, but it branches strongly after
+making most of its height growth. The mature tree is
+usually forked, and the place where the forking commences
+determines the number of logs in the tree or its merchantable
+length, by preventing cutting to a small diameter in
+the top. On large trees the stem is often not less than
+eighteen inches in diameter where the branching begins.
+The over-mature tree is usually broken and dry topped,
+with a very spreading crown, in consequence of new
+branches being sent out.</p>
+
+
+<h4>Tolerance of Red Gum</h4>
+
+<p>Throughout its entire life red gum is intolerant in shade,
+there are practically no red seedlings under the dense
+forest cover of the bottom land, and while a good many
+may come up under the pine forest on the drier uplands,
+they seldom develop into large trees. As a rule seedlings
+appear only in clearings or in open spots in the forest. It
+is seldom that an over-topped tree is found, for the gum
+dies quickly if suppressed, and is consequently nearly
+always a dominant or intermediate tree. In a hardwood
+bottom forest the timber trees are all of nearly the same
+age over considerable areas, and there is little young
+growth to be found in the older stands. The reason for
+this is the intolerance of most of the swamp species. A
+scale of intolerance containing the important species, and
+beginning with the most light-demanding, would run as
+follows: Cottonwood, sycamore, red gum, white elm,
+white ash, and red maple.</p>
+
+
+<h4>Demands upon Soil and Moisture</h4>
+
+<p>While the red gum grows in various situations, it prefers
+the deep, rich soil of the hardwood bottoms, and there
+reaches its best development (see <a href="#Fig_10">Fig. 10</a>). It requires
+considerable soil moisture, though it does not grow
+in the wetter swamps, and does not thrive on dry pine land.
+Seedlings, however, are often found in large numbers on
+the edges of the uplands and even on the sandy pine land,
+but they seldom live beyond the pole stage. When they<span class='pagenum'><a name="Page_57" id="Page_57">[57]</a></span>
+do, they form small, scrubby trees that are of little value.
+Where the soil is dry the tree has a long tap root. In the
+swamps, where the roots can obtain water easily, the development
+of the tap root is poor, and it is only moderate
+on the glade bottom lands, where there is considerable
+moisture throughout the year, but no standing water in
+the summer months.</p>
+
+
+<h4>Reproduction of Red Gum</h4>
+
+<div class="figcenter" style="width: 400px;"><p class="anchor"><a name="Fig_12" id="Fig_12"></a></p>
+<img src="images/fig12.jpg" width="400" height="298" alt="Second Growth Red Gum" title="Second Growth Red Gum" />
+
+<p class="caption" style="text-align: center">Fig. 12. Second Growth Red Gum, Ash, Cottonwood, and Sycamore.</p>
+</div>
+
+<p>Red gum reproduces both by seed and by sprouts
+(see <a href="#Fig_12">Fig. 12</a>). It produces seed fairly abundantly every
+year, but about once in three years there is an extremely
+heavy production. The tree begins to bear seed when
+twenty-five to thirty years old, and seeds vigorously up
+to an age of one hundred and fifty years, when its productive
+power begins to diminish. A great part of the
+seed, however, is abortive. Red gum is not fastidious in
+regard to its germinating bed; it comes up readily on sod<span class='pagenum'><a name="Page_58" id="Page_58">[58]</a></span>
+in old fields and meadows, on decomposing humus in the
+forest, or on bare clay-loam or loamy sand soil. It requires
+a considerable degree of light, however, and prefers
+a moist seed bed. The natural distribution of the seed
+takes place for several hundred feet from the seed trees,
+the dissemination depending almost entirely on the wind.
+A great part of the seed falls on the hardwood bottom when
+the land is flooded, and is either washed away or, if already<span class='pagenum'><a name="Page_59" id="Page_59">[59]</a></span>
+in the ground and germinating, is destroyed by the long-continued
+overflow. After germinating, the red gum
+seedling demands, above everything else, abundant light
+for its survival and development. It is for this reason
+that there is very little growth of red gum, either in the
+unculled forest or on culled land, where, as is usually the
+case, a dense undergrowth of cane, briers, and rattan is
+present. Under the dense underbrush of cane and briers
+throughout much of the virgin forest, reproduction of any
+of the merchantable species is of course impossible. And
+even where the land has been logged over, the forest is
+seldom open enough to allow reproduction of cottonwood
+and red gum. Where, however, seed trees are contiguous
+to pastures or cleared land, scattered seedlings are found
+springing up in the open, and where openings occur in the
+forest, there are often large numbers of red gum seedlings,
+the reproduction generally occurring in groups. But over
+the greater part of the Southern hardwood bottom land
+forest reproduction is very poor. The growth of red gum
+during the early part of its life, and up to the time it
+reaches a diameter of eight inches breast-high, is extremely
+rapid, and, like most of the intolerant species, it attains
+its height growth at an early period. Gum sprouts readily
+from the stump, and the sprouts surpass the seedlings in
+rate of height growth for the first few years, but they seldom
+form large timber trees. Those over fifty years of
+age seldom sprout. For this reason sprout reproduction
+is of little importance in the forest. The principal requirements
+of red gum, then, are a moist, fairly rich soil
+and good exposure to light. Without these it will not
+reach its best development.</p>
+
+<div class="figcenter" style="width: 400px;"><p class="anchor"><a name="Fig_13" id="Fig_13"></a></p>
+<img src="images/fig13.jpg" width="400" height="506" alt="A Cypress Slough in the Dry Season" title="A Cypress Slough in the Dry Season" />
+
+<p class="caption" style="text-align: center">Fig. 13. A Cypress Slough in the Dry Season.</p>
+</div>
+
+
+<h4>Second-Growth Red Gum</h4>
+
+<p>Second-growth red gum occurs to any considerable extent
+only on land which has been thoroughly cleared.
+Throughout the South there is a great deal of land which
+was in cultivation before the Civil War, but which during
+the subsequent period of industrial depression was abandoned
+and allowed to revert to forest. These old fields
+now mostly covered with second-growth forest, of<span class='pagenum'><a name="Page_60" id="Page_60">[60]</a></span>
+which red gum forms an important part (see <a href="#Fig_12">Fig. 12</a>).
+Frequently over fifty per cent of the stand consists of this
+species, but more often, and especially on the Atlantic
+coast, the greater part is of cottonwood or ash. These
+stands are very dense, and the growth is extremely rapid.
+Small stands of young growth are also often found along
+the edges of cultivated fields. In the Mississippi Valley
+the abandoned fields on which young stands have sprung
+up are for the most part being rapidly cleared again. The
+second growth here is considered of little value in comparison
+with the value of the land for agricultural purposes.
+In many cases, however, the farm value of the land is not
+at present sufficient to make it profitable to clear it, unless
+the timber cut will at least pay for the operation. There
+is considerable land upon which the second growth will
+become valuable timber within a few years. Such land
+should not be cleared until it is possible to utilize the
+timber.</p>
+
+<p class="negative"><b>39. Tupelo Gum</b> (<i>Nyssa aquatica</i>) (Bay Poplar, Swamp
+Poplar, Cotton Gum, Hazel Pine, Circassian Walnut,
+Pepperidge, Nyssa). The close similarity which exists
+between red and tupelo gum, together with the
+fact that tupelo is often cut along with red gum, and
+marketed with the sapwood of the latter, makes it
+not out of place to give consideration to this timber.
+The wood has a fine, uniform texture, is moderately
+hard and strong, is stiff, not elastic, very tough and
+hard to split, but easy to work with tools. Tupelo
+takes glue, paint, or varnish well, and absorbs very
+little of the material. In this respect it is equal to
+yellow poplar and superior to cottonwood. The
+wood is not durable in contact with ground, and requires
+much care in seasoning. The distinction between
+the heartwood and sapwood of this species is
+marked. The former varies in color from a dull gray
+to a dull brown; the latter is whitish or light yellow
+like that of poplar. The wood is of medium weight,
+about thirty-two pounds per cubic foot when dry, or
+nearly that of red gum and loblolly pine. After<span class='pagenum'><a name="Page_61" id="Page_61">[61]</a></span>
+seasoning it is difficult to distinguish the better grades
+of sapwood from poplar. Owing to the prejudice
+against tupelo gum, it was until recently marketed
+under such names as bay poplar, swamp poplar, nyssa,
+cotton gum, circassian walnut, and hazel pine. Since
+it has become evident that the properties of the wood
+fit it for many uses, the demand for tupelo has largely
+increased, and it is now taking rank with other standard
+woods under its rightful name. Heretofore the
+quality and usefulness of this wood were greatly
+underestimated, and the difficulty of handling it was
+magnified. Poor success in seasoning and kiln-drying
+was laid to defects of the wood itself, when, as a
+matter of fact, the failures were largely due to the
+absence of proper methods in handling. The passing
+of this prejudice against tupelo is due to a better
+understanding of the characteristics and uses of the
+wood. Handled in the way in which its particular
+character demands, tupelo is a wood of much value.</p>
+
+
+<h4>Uses of Tupelo Gum</h4>
+
+<p>Tupelo gum is now used in slack cooperage, principally
+for heading. It is used extensively for house flooring and
+inside finishing, such as mouldings, door jambs, and casings.
+A great deal is now shipped to European countries, where
+it is highly valued for different classes of manufacture.
+Much of the wood is used in the manufacture of boxes, since
+it works well upon rotary veneer machines. There is also
+an increasing demand for tupelo for laths, wooden pumps,
+violin and organ sounding boards, coffins, mantelwork,
+conduits and novelties. It is also used in the furniture
+trade for backing, drawers, and panels.</p>
+
+
+<h4>Range of Tupelo Gum</h4>
+
+<p>Tupelo occurs throughout the coastal region of the Atlantic
+States, from southern Virginia to northern Florida,
+through the Gulf States to the valley of the Nueces River
+in Texas, through Arkansas and southern Missouri to
+western Kentucky and Tennessee, and to the valley of<span class='pagenum'><a name="Page_62" id="Page_62">[62]</a></span>
+the lower Wabash River. Tupelo is being extensively
+milled at present only in the region adjacent to Mobile
+Ala., and in southern and central Louisiana, where it
+occurs in large merchantable quantities, attaining its
+best development in the former locality. The country
+in this locality is very swampy (see <a href="#Fig_11">Fig. 11</a>), and within
+a radius of one hundred miles tupelo gum is one of the
+principal timber trees. It grows only in the swamps and
+wetter situations (see <a href="#Fig_11">Fig. 11</a>), often in mixture with
+cypress, and in the rainy season it stands in from two to
+twenty feet of water.</p>
+
+<p class="negative"><b>40. Black Gum</b> (<i>Nyssa sylvatica</i>) (Sour Gum). Black
+gum is not cut to much extent, owing to its less abundant
+supply and poorer quality, but is used for repair
+work on wagons, for boxes, crates, wagon hubs,
+rollers, bowls, woodenware, and for cattle yokes and
+other purposes which require a strong, non-splitting
+wood. Heartwood is light brown in color, often
+nearly white; sapwood hardly distinguishable, fine
+grain, fibres interwoven. Wood is heavy, not hard,
+difficult to work, strong, very tough, checks and
+warps considerably in drying, not durable. It is
+distributed from Maine to southern Ontario, through
+central Michigan to southeastern Missouri, southward
+to the valley of the Brazos River in Texas, and
+eastward to the Kissimmee River and Tampa Bay
+in Florida. It is found in the swamps and hardwood
+bottoms, but is more abundant and of better size on the
+slightly higher ridges and hummocks in these swamps,
+and on the mountain slopes in the southern Alleghany
+region. Though its range is greater than that of
+either red or tupelo gum, it nowhere forms an important
+part of the forest.</p>
+
+
+<h4>HACKBERRY</h4>
+
+<p class="negative"><b>41. Hackberry</b> (<i>Celtis occidentalis</i>) (Sugar Berry, Nettle
+Tree). The wood is handsome, heavy, hard, strong,
+quite tough, of moderately fine texture, and greenish
+or yellowish color, shrinks moderately, works well<span class='pagenum'><a name="Page_63" id="Page_63">[63]</a></span>
+and stands well, and takes a good polish. Used to
+some extent in cooperage, and in the manufacture of
+cheap furniture. Medium- to large-sized tree, locally
+quite common, largest in the lower Mississippi Valley.
+Occurs in nearly all parts of the eastern United States.</p>
+
+
+<h4>HICKORY</h4>
+
+<p>The hickories of commerce are exclusively North American
+and some of them are large and beautiful trees of
+60 to 70 feet or more in height. They are closely allied
+to the walnut, and the wood is very like walnut in grain
+and color, though of a somewhat darker brown. It is one
+of the finest of American hardwoods in point of strength;
+in toughness it is superior to ash, rather coarse in texture,
+smooth and of straight grain, very heavy and strong as
+well as elastic and tenacious, but decays rapidly, especially
+the sapwood when exposed to damp and moisture, and
+is very liable to attack from worms and boring insects.
+The cross-section of hickory is peculiar, the annual rings
+appear like fine lines instead of like the usual pores, and
+the medullary rays, which are also very fine but distinct,
+in crossing these form a peculiar web-like pattern which
+is one of the characteristic differences between hickory
+and ash. Hickory is rarely subjected to artificial treatment,
+but there is this curious fact in connection with the
+wood, that, contrary to most other woods, creosote is
+only with difficulty injected into the sap, although there
+is no difficulty in getting it into the heartwood. It dries
+slowly, shrinks and checks considerably in seasoning; is not
+durable in contact with the soil or if exposed. Hickory
+excels as wagon and carriage stock, for hoops in cooperage,
+and is extensively used in the manufacture of implements
+and machinery, for tool handles, timber pins,
+harness work, dowel pins, golf clubs, and fishing rods.
+The hickories are tall trees with slender stems, never forming
+forests, occasionally small groves, but usually occur
+scattered among other broad-leaved trees in suitable localities.
+The following species all contribute more or less
+to the hickory of the markets:<span class='pagenum'><a name="Page_64" id="Page_64">[64]</a></span></p>
+
+<p class="negative"><b>42. Shagbark Hickory</b> (<i>Hicoria ovata</i>) (Shellbark Hickory,
+Scalybark Hickory). A medium- to large-sized
+tree, quite common; the favorite among the hickories.
+Heartwood light brown, sapwood ivory or cream-colored.
+Wood close-grained, compact structure,
+annual rings clearly marked. Very hard, heavy,
+strong, tough, and flexible, but not durable in contact
+with the soil or when exposed. Used for agricultural
+implements, wheel runners, tool handles,
+vehicle parts, baskets, dowel pins, harness work, golf
+clubs, fishing rods, etc. Best developed in the Ohio
+and Mississippi basins; from Lake Ontario to Texas,
+Minnesota to Florida.</p>
+
+<p class="negative"><b>43. Mockernut Hickory</b> (<i>Hicoria alba</i>) (Black Nut Hickory,
+Black Hickory, Bull Nut Hickory, Big Bud
+Hickory, White Heart Hickory). A medium- to large-sized
+tree. Wood in its quality and uses similar to
+the preceding. Its range is the same as that of
+<i>Hicoria ovata</i>. Common, especially in the South.</p>
+
+<p class="negative"><b>44. Pignut Hickory</b> (<i>Hicoria glabra</i>) (Brown Hickory,
+Black Hickory, Switchbud Hickory). A medium- to
+large-sized tree. Heavier and stronger than any
+of the preceding. Heartwood light to dark brown,
+sapwood nearly white. Abundant, all eastern United
+States.</p>
+
+<p class="negative"><b>45. Bitternut Hickory</b> (<i>Hicoria minima</i>) (Swamp Hickory).
+A medium-sized tree, favoring wet localities.
+Heartwood light brown, sapwood lighter color. Wood
+in its quality and uses not so valuable as <i>Hicoria
+ovata</i>, but is used for the same purposes. Abundant,
+all eastern United States.</p>
+
+<p class="negative"><b>46. Pecan</b> (<i>Hicoria pecan</i>) (Illinois Nut). A large tree,
+very common in the fertile bottoms of the western
+streams. Indiana to Nebraska and southward to
+Louisiana and Texas.</p>
+
+
+<h4>HOLLY</h4>
+
+<p class="negative"><b>47. Holly</b> (<i>Ilex opaca</i>). Small to medium-sized tree.
+Wood of medium weight, hard, strong, tough, of<span class='pagenum'><a name="Page_65" id="Page_65">[65]</a></span>
+exceedingly fine grain, closer in texture than most
+woods, of white color, sometimes almost as white as
+ivory; requires great care in its treatment to preserve
+the whiteness of the wood. It does not readily
+absorb foreign matter. Much used by turners and
+for all parts of musical instruments, for handles on
+whips and fancy articles, draught-boards, engraving
+blocks, cabinet work, etc. The wood is often dyed
+black and sold as ebony; works well and stands well.
+Most abundant in the lower Mississippi Valley and
+Gulf States, but occurring eastward to Massachusetts
+and north to Indiana.</p>
+
+<p class="negative"><b>48. Holly</b> (<i>Ilex monticolo</i>) (Mountain Holly). Small-sized
+tree. Wood in its quality and uses similar to
+the preceding, but is not very generally known. It
+is found in the Catskill Mountains and extends southward
+along the Alleghanies as far as Alabama.</p>
+
+
+<h4>HORSE CHESTNUT (See Buckeye)</h4>
+
+<h4>IRONWOOD</h4>
+
+<p class="negative"><b>49. Ironwood</b> (<i>Ostrya Virginiana</i>) (Hop Hornbeam, Lever
+Wood). Small-sized tree, common. Heartwood light
+brown tinged with red, sapwood nearly white. Wood
+heavy, tough, exceedingly close-grained, very strong
+and hard, durable in contact with the soil, and will
+take a fine polish. Used for small articles like levers,
+handles of tools, mallets, etc. Ranges throughout
+the United States east of the Rocky Mountains.</p>
+
+
+<h4>LAUREL</h4>
+
+<p class="negative"><b>50. Laurel</b> (<i>Umbellularia Californica</i>) (Myrtle). A Western
+tree, produces timber of light brown color of great
+size and beauty, and is very valuable for cabinet and
+inside work, as it takes a fine polish. California and
+Oregon, coast range of the Sierra Nevada Mountains.<span class='pagenum'><a name="Page_66" id="Page_66">[66]</a></span></p>
+
+
+<h4>LOCUST</h4>
+
+<p class="negative"><b>51. Black Locust</b> (<i>Robinia pseudacacia</i>) (Locust, Yellow
+Locust, Acacia). Small to medium-sized tree. Wood
+very heavy, hard, strong, and tough, rivalling some
+of the best oak in this latter quality. The wood has
+great torsional strength, excelling most of the soft
+woods in this respect, of coarse texture, close-grained
+and compact structure, takes a fine polish. Annual
+rings clearly marked, very durable in contact with
+the soil, shrinks and checks considerably in drying,
+the very narrow sapwood greenish yellow, the heartwood brown,
+with shades of red and green. Used
+for wagon hubs, trenails or pins, but especially for
+railway ties, fence posts, and door sills. Also used
+for boat parts, turnery, ornamentations, and locally
+for construction. Abroad it is much used for furniture
+and farming implements and also in turnery. At
+home in the Alleghany Mountains, extensively planted,
+especially in the West.</p>
+
+<p class="negative"><b>52. Honey Locust</b> (<i>Gleditschia triacanthos</i>) (Honey Shucks,
+Locust, Black Locust, Brown Locust, Sweet Locust,
+False Acacia, Three-Thorned Acacia). A medium-sized
+tree. Wood heavy, hard, strong, tough, durable
+in contact with the soil, of coarse texture, susceptible
+to a good polish. The narrow sapwood yellow,
+the heartwood brownish red. So far, but little appreciated
+except for fences and fuel. Used to some
+extent for wheel hubs, and locally in rough construction.
+Found from Pennsylvania to Nebraska,
+and southward to Florida and Texas; locally quite
+abundant.</p>
+
+<p class="negative"><b>53. Locust</b> (<i>Robinia viscosa</i>) (Clammy Locust). Usually
+a shrub five or six feet high, but known to reach a
+height of 40 feet in the mountains of North Carolina,
+with the habit of a tree. Wood light brown, heavy,
+hard, and close-grained. Not used to much extent
+in manufacture. Range same as the preceding.<span class='pagenum'><a name="Page_67" id="Page_67">[67]</a></span></p>
+
+
+<h4>MAGNOLIA</h4>
+
+<p class="negative"><b>54. Magnolia</b> (<i>Magnolia glauca</i>) (Swamp Magnolia, Small
+Magnolia, Sweet Bay, Beaver Wood). Small-sized
+tree. Heartwood reddish brown, sap wood cream
+white. Sparingly used in manufacture. Ranges from
+Essex County, Mass., to Long Island, N.&nbsp;Y., from
+New Jersey to Florida, and west in the Gulf region
+to Texas.</p>
+
+<p class="negative"><b>55. Magnolia</b> (<i>Magnolia tripetala</i>) (Umbrella Tree). A
+small-sized tree. Wood in its quality similiar to the
+preceding. It may be easily recognized by its great
+leaves, twelve to eighteen inches long, and five to
+eight inches broad. This species as well as the preceding
+is an ornamental tree. Ranges from Pennsylvania
+southward to the Gulf.</p>
+
+<p class="negative"><b>56. Cucumber Tree</b> (<i>Magnolia accuminata</i>) (Tulip-wood,
+Poplar). Medium- to large-sized tree. Heartwood
+yellowish brown, sapwood almost white. Wood light,
+soft, satiny, close-grained, durable in contact with
+the soil, resembling and sometimes confounded with
+tulip tree (<i>Liriodendron tulipifera</i>) in the markets.
+The wood shrinks considerably, but seasons without
+much injury, and works and stands well. It bends
+readily when steamed, and takes stain and paint well.
+Used in cooperage, for siding, for panelling and finishing
+lumber in house, car and shipbuilding, etc., also
+in the manufacture of toys, culinary woodenware, and
+backing for drawers. Most common in the southern
+Alleghanies, but distributed from western New York
+to southern Illinois, south through central Kentucky
+and Tennessee to Alabama, and throughout
+Arkansas.</p>
+
+
+<h4>MAPLE</h4>
+
+<p>Wood heavy, hard, strong, stiff, and tough, of fine
+texture, frequently wavy-grained, this giving rise to
+"curly" and "blister" figures which are much admired.
+Not durable in the ground, or when exposed. Maple<span class='pagenum'><a name="Page_68" id="Page_68">[68]</a></span>
+is creamy white, with shades of light brown in the heartwood,
+shrinks moderately, seasons, works, and stands well,
+wears smoothly, and takes a fine polish. The wood is
+used in cooperage, and for ceiling, flooring, panelling,
+stairway, and other finishing lumber in house, ship, and
+car construction. It is used for the keels of boats and ships,
+in the manufacture of implements and machinery, but
+especially for furniture, where entire chamber sets of
+maple rival those of oak. Maple is also used for shoe
+lasts and other form blocks; for shoe pegs; for piano
+actions, school apparatus, for wood type in show bill
+printing, tool handles, in wood carving, turnery, and
+scroll work, in fact it is one of our most useful woods.
+The maples are medium-sized trees, of fairly rapid growth,
+sometimes form forests, and frequently constitute a large
+proportion of the arborescent growth. They grow freely
+in parts of the Northern Hemisphere, and are particularly
+luxuriant in Canada and the northern portions of the
+United States.</p>
+
+<p class="negative"><b>57. Sugar Maple</b> (<i>Acer saccharum</i>) (Hard Maple, Rock
+Maple). Medium- to large-sized tree, very common,
+forms considerable forests, and is especially esteemed.
+The wood is close-grained, heavy, fairly hard and
+strong, of compact structure. Heartwood brownish,
+sapwood lighter color; it can be worked to a satin-like
+surface and take a fine polish, it is not durable
+if exposed, and requires a good deal of seasoning.
+Medullary rays small but distinct. The "curly"
+or "wavy" varieties furnish wood of much beauty,
+the peculiar contortions of the grain called "bird's
+eye" being much sought after, and used as veneer for
+panelling, etc. It is used in all good grades of furniture,
+cabinetmaking, panelling, interior finish, and
+turnery; it is not liable to warp and twist. It is also
+largely used for flooring, for rollers for wringers and
+mangling machines, for which there is a large and
+increasing demand. The peculiarity known as "bird's
+eye," and which causes a difficulty in working the
+wood smooth, owing to the little pieces like knots<span class='pagenum'><a name="Page_69" id="Page_69">[69]</a></span>
+lifting up, is supposed to be due to the action of boring
+insects. Its resistance to compression across the
+grain is higher than that of most other woods. Ranges
+from Maine to Minnesota, abundant, with birch, in
+the region of the Great Lakes.</p>
+
+<p class="negative"><b>58. Red Maple</b> (<i>Acer rubrum</i>) (Swamp Maple, Soft
+Maple, Water Maple). Medium-sized tree. Like
+the preceding but not so valuable. Scattered along
+water-courses and other moist localities. Abundant.
+Maine to Minnesota, southward to northern Florida.</p>
+
+<p class="negative"><b>59. Silver Maple</b> (<i>Acer saccharinum</i>) (Soft Maple, White
+Maple, Silver-Leaved Maple). Medium- to large-sized
+tree, common. Wood lighter, softer, and inferior
+to <i>Acer saccharum</i>, and usually offered in small
+quantities and held separate in the markets. Heartwood
+reddish brown, sapwood ivory white, fine-grained,
+compact structure. Fibres sometimes
+twisted, weaved, or curly. Not durable. Used in
+cooperage for woodenware, turnery articles, interior
+decorations and flooring. Valley of the Ohio, but
+occurs from Maine to Dakota and southward to
+Florida.</p>
+
+<p class="negative"><b>60. Broad-Leaved Maple</b> (<i>Acer macrophyllum</i>) (Oregon
+Maple). Medium-sized tree, forms considerable
+forests, and, like the preceding has a lighter, softer,
+and less valuable wood than <i>Acer saccharum</i>. Pacific
+Coast regions.</p>
+
+<p class="negative"><b>61. Mountain Maple</b> (<i>Acer spicatum</i>). Small-sized tree.
+Heartwood pale reddish brown, sapwood lighter color.
+Wood light, soft, close-grained, and susceptible of
+high polish. Ranges from lower St. Lawrence River
+to northern Minnesota and regions of the Saskatchewan
+River; south through the Northern States and
+along the Appalachian Mountains to Georgia.</p>
+
+<p class="negative"><b>62. Ash-Leaved Maple</b> (<i>Acer negundo</i>) (Box Elder).
+Medium- to large-sized tree. Heartwood creamy
+white, sapwood nearly white. Wood light, soft, close-grained,<span class='pagenum'><a name="Page_70" id="Page_70">[70]</a></span>
+not strong. Used for woodenware and paper
+pulp. Distributed across the continent, abundant
+throughout the Mississippi Valley along banks of
+streams and borders of swamps.</p>
+
+<p class="negative"><b>63. Striped Maple</b> (<i>Acer Pennsylvanicum</i>) (Moose-wood).
+Small-sized tree. Produces a very white wood much
+sought after for inlaid and for cabinet work. Wood
+is light, soft, close-grained, and takes a fine polish.
+Not common. Occurs from Pennsylvania to Minnesota.</p>
+
+
+<h4>MULBERRY</h4>
+
+<p class="negative"><b>64. Red Mulberry</b> (<i>Morus rubra</i>). A small-sized tree.
+Wood moderately heavy, fairly hard and strong,
+rather tough, of coarse texture, very durable in contact
+with the soil. The sapwood whitish, heartwood
+yellow to orange brown, shrinks and checks considerably
+in drying, works well and stands well. Used
+in cooperage and locally in construction, and in the
+manufacture of farm implements. Common in the
+Ohio and Mississippi Valleys, but widely distributed
+in the eastern United States.</p>
+
+
+<h4>MYRTLE (See Laurel)</h4>
+
+<h4>OAK</h4>
+
+<p>Wood very variable, usually very heavy and hard, very
+strong and tough, porous, and of coarse texture. The
+sapwood whitish, the heartwood "oak" to reddish brown.
+It shrinks and checks badly, giving trouble in seasoning,
+but stands well, is durable, and little subject to the attacks
+of boring insects. Oak is used for many purposes,
+and is the chief wood used for tight cooperage; it is used
+in shipbuilding, for heavy construction, in carpentry, in
+furniture, car and wagon work, turnery, and even in woodcarving.
+It is also used in all kinds of farm implements,
+mill machinery, for piles and wharves, railway ties, etc.,
+etc. The oaks are medium- to large-sized trees, forming
+the predominant part of a large proportion of our broad-leaved<span class='pagenum'><a name="Page_71" id="Page_71">[71]</a></span>
+forests, so that these are generally termed "oak
+forests," though they always contain considerable proportion
+of other kinds of trees. Three well-marked kinds&mdash;white,
+red, and live oak&mdash;are distinguished and kept
+separate in the markets. Of the two principal kinds
+"white oak" is the stronger, tougher, less porous, and
+more durable. "Red oak" is usually of coarser texture,
+more porous, often brittle, less durable, and even more
+troublesome in seasoning than white oak. In carpentry
+and furniture work red oak brings the same price at present
+as white oak. The red oaks everywhere accompany the
+white oaks, and, like the latter, are usually represented
+by several species in any given locality. "Live oak,"
+once largely employed in shipbuilding, possesses all the
+good qualities, except that of size, of white oak, even to
+a greater degree. It is one of the heaviest, hardest, toughest,
+and most durable woods of this country. In structure
+it resembles the red oak, but is less porous.</p>
+
+<p class="negative"><b>65. White Oak</b> (<i>Quercus alba</i>) (American Oak). Medium-
+to large-sized tree. Heartwood light brown,
+sapwood lighter color. Annual rings well marked,
+medullary rays broad and prominent. Wood tough,
+strong, heavy, hard, liable to check in seasoning,
+durable in contact with the soil, takes a high polish,
+very elastic, does not shrink much, and can be bent
+to any form when steamed. Used for agricultural
+implements, tool handles, furniture, fixtures, interior
+finish, car and wagon construction, beams,
+cabinet work, tight cooperage, railway ties, etc., etc.
+Because of the broad medullary rays, it is generally
+"quarter-sawn" for cabinet work and furniture.
+Common in the Eastern States, Ohio and Mississippi
+Valleys. Occurs throughout the eastern United
+States.</p>
+
+<p class="negative"><b>66. White Oak</b> (<i>Quercus durandii</i>). Medium- to small-sized
+tree. Wood in its quality and uses similiar to
+the preceding. Texas, eastward to Alabama.</p>
+
+<p class="negative"><b>67. White Oak</b> (<i>Quercus garryana</i>) (Western White Oak).
+Medium- to large-sized tree. Stronger, more durable,<span class='pagenum'><a name="Page_72" id="Page_72">[72]</a></span>
+and wood more compact than <i>Quercus alba</i>. Washington
+to California.</p>
+
+<p class="negative"><b>68. White Oak</b> (<i>Quercus lobata</i>). Medium- to large-sized
+tree. Largest oak on the Pacific Coast. Wood in
+its quality and uses similar to <i>Quercus alba</i>, only it
+is finer-grained. California.</p>
+
+<p class="negative"><b>69. Bur Oak</b> (<i>Quercus macrocarpa</i>) (Mossy-Cup Oak,
+Over-Cup Oak). Large-sized tree. Heartwood "oak"
+brown, sapwood lighter color. Wood heavy, strong,
+close-grained, durable in contact with the soil.
+Used in ship- and boatbuilding, all sorts of construction,
+interior finish of houses, cabinet work,
+tight cooperage, carriage and wagon work, agricultural
+implements, railway ties, etc., etc. One of the most
+valuable and most widely distributed of American
+oaks, 60 to 80 feet in height, and, unlike most of the
+other oaks, adapts itself to varying climatic conditions.
+It is one of the most durable woods when in
+contact with the soil. Common, locally abundant.
+Ranges from Manitoba to Texas, and from the foot
+hills of the Rocky Mountains to the Atlantic Coast.
+It is the most abundant oak of Kansas and Nebraska,
+and forms the scattered forests known as "The oak
+openings" of Minnesota.</p>
+
+<p class="negative"><b>70. Willow Oak</b> (<i>Quercus phellos</i>) (Peach oak). Small
+to medium-sized tree. Heartwood pale reddish brown,
+sapwood lighter color. Wood heavy, hard, strong,
+coarse-grained. Occasionally used in construction.
+New York to Texas, and northward to Kentucky.</p>
+
+<p class="negative"><b>71. Swamp White Oak</b> (<i>Quercus bicolor</i> var. <i>platanoides</i>).
+Large-sized tree. Heartwood pale brown, sapwood
+the same color. Wood heavy, hard, strong, tough,
+coarse-grained, checks considerably in seasoning.
+Used in construction, interior finish of houses, carriage-
+and boatbuilding, agricultural implements, in cooperage,
+railway ties, fencing, etc., etc. Ranges from
+Quebec to Georgia and westward to Arkansas. Never
+abundant. Most abundant in the Lake States.<span class='pagenum'><a name="Page_73" id="Page_73">[73]</a></span></p>
+
+<p class="negative"><b>72. Over-Cup Oak</b> (<i>Quercus lyrata</i>) (Swamp White Oak,
+Swamp Post Oak). Medium to large-sized tree,
+rather restricted, as it grows in the swampy districts
+of Carolina and Georgia. Is a larger tree than most
+of the other oaks, and produces an excellent timber,
+but grows in districts difficult of access, and is not
+much used. Lower Mississippi and eastward to
+Delaware.</p>
+
+<p class="negative"><b>73. Pin Oak</b> (<i>Quercus palustris</i>) (Swamp Spanish Oak,
+Water Oak). Medium- to large-sized tree. Heartwood
+pale brown with dark-colored sap wood. Wood
+heavy, strong, and coarse-grained. Common along
+the borders of streams and swamps, attains its greatest
+size in the valley of the Ohio. Arkansas to Wisconsin,
+and eastward to the Alleghanies.</p>
+
+<p class="negative"><b>74. Water Oak</b> (<i>Quercus aquatica</i>) (Duck Oak, Possum
+Oak). Medium- to large-sized tree, of extremely
+rapid growth. Eastern Gulf States, eastward to
+Delaware and northward to Missouri and Kentucky.</p>
+
+<p class="negative"><b>75. Chestnut Oak</b> (<i>Quercus prinus</i>) (Yellow Oak, Rock
+Oak, Rock Chestnut Oak). Heartwood dark brown,
+sapwood lighter color. Wood heavy, hard, strong,
+tough, close-grained, durable in contact with the soil.
+Used for railway ties, fencing, fuel, and locally for
+construction. Ranges from Maine to Georgia and
+Alabama, westward through Ohio, and southward
+to Kentucky and Tennessee.</p>
+
+<p class="negative"><b>76. Yellow Oak</b> (<i>Quercus acuminata</i>) (Chestnut Oak,
+Chinquapin Oak). Medium- to large-sized tree.
+Heartwood dark brown, sapwood pale brown. Wood
+heavy, hard, strong, close-grained, durable in contact
+with the soil. Used in the manufacture of wheel
+stock, in cooperage, for railway ties, fencing, etc.,
+etc. Ranges from New York to Nebraska and eastern
+Kansas, southward in the Atlantic region to the
+District of Columbia, and west of the Alleghanies
+southward to the Gulf States.<span class='pagenum'><a name="Page_74" id="Page_74">[74]</a></span></p>
+
+<p class="negative"><b>77. Chinquapin Oak</b> (<i>Quercus prinoides</i>) (Dwarf Chinquapin
+Oak, Scrub Chestnut Oak). Small-sized tree.
+Heartwood light brown, sapwood darker color. Does
+not enter the markets to any great extent. Ranges
+from Massachusetts to North Carolina, westward to
+Missouri, Nebraska, Kansas, and eastern Texas.
+Reaches its best form in Missouri and Kansas.</p>
+
+<p class="negative"><b>78. Basket Oak</b> (<i>Quercus michauxii</i>) (Cow Oak). Large-sized
+tree. Locally abundant. Lower Mississippi
+and eastward to Delaware.</p>
+
+<p class="negative"><b>79. Scrub Oak</b> (<i>Quercus ilicifolia</i> var. <i>pumila</i>) (Bear Oak).
+Small-sized tree. Heartwood light brown, sapwood
+darker color. Wood heavy, hard, strong, and coarse-grained.
+Found in New England and along the
+Alleghanies.</p>
+
+<p class="negative"><b>80. Post Oak</b> (<i>Quercus obtusiloda</i> var. <i>minor</i>) (Iron Oak).
+Medium- to large-sized tree, gives timber of great
+strength. The color is of a brownish yellow hue,
+close-grained, and often superior to the white oak
+(<i>Quercus alba</i>) in strength and durability. It is used
+for posts and fencing, and locally for construction.
+Arkansas to Texas, eastward to New England and
+northward to Michigan.</p>
+
+<p class="negative"><b>81. Red Oak</b> (<i>Quercus rubra</i>) (Black Oak). Medium- to
+large-sized tree. Heartwood light brown to red, sapwood
+lighter color. Wood coarse-grained, well-marked
+annual rings, medullary rays few but broad. Wood
+heavy, hard, strong, liable to check in seasoning.
+It is found over the same range as white oak, and
+is more plentiful. Wood is spongy in grain, moderately
+durable, but unfit for work requiring strength.
+Used for agricultural implements, furniture, bob
+sleds, vehicle parts, boxes, cooperage, woodenware,
+fixtures, interior finish, railway ties, etc., etc. Common
+in all parts of its range. Maine to Minnesota,
+and southward to the Gulf.</p>
+
+<p class="negative"><b>82. Black Oak</b> (<i>Quercus tinctoria</i> var. <i>velutina</i>) (Yellow
+Oak). Medium- to large-sized tree. Heartwood<span class='pagenum'><a name="Page_75" id="Page_75">[75]</a></span>
+bright brown tinged with red, sapwood lighter color.
+Wood heavy, hard, strong, coarse-grained, checks
+considerably in seasoning. Very common in the
+Southern States, but occurring North as far as Minnesota,
+and eastward to Maine.</p>
+
+<p class="negative"><b>83. Barren Oak</b> (<i>Quercus nigra</i> var. <i>marilandica</i>) (Black
+Jack, Jack Oak). Small-sized tree. Heartwood
+dark brown, sapwood lighter color. Wood heavy,
+hard, strong, coarse-grained, not valuable. Used
+in the manufacture of charcoal and for fuel. New
+York to Kansas and Nebraska, and southward to
+Florida. Rare in the North, but abundant in the
+South.</p>
+
+<p class="negative"><b>84. Shingle Oak</b> (<i>Quercus imbricaria</i>) (Laurel Oak). Small
+to medium-sized tree. Heartwood pale reddish
+brown, sapwood lighter color. Wood heavy, hard,
+strong, coarse-grained, checks considerably in drying.
+Used for shingles and locally for construction.
+Rare in the east, most abundant in the lower Ohio
+Valley. From New York to Illinois and southward.
+Reaches its greatest size in southern Illinois and
+Indiana.</p>
+
+<p class="negative"><b>85. Spanish Oak</b> (<i>Quercus digitata</i> var. <i>falcata</i>) (Red Oak).
+Medium-sized tree. Heartwood light reddish brown,
+sapwood much lighter. Wood heavy, hard, strong,
+coarse-grained, and checks considerably in seasoning.
+Used locally for construction, and has high fuel value.
+Common in south Atlantic and Gulf region, but found
+from Texas to New York, and northward to Missouri
+and Kentucky.</p>
+
+<p class="negative"><b>86. Scarlet Oak</b> (<i>Quercus coccinea</i>). Medium- to large-sized
+tree. Heartwood light reddish-brown, sapwood
+darker color. Wood heavy, hard, strong, and
+coarse-grained. Best developed in the lower basin
+of the Ohio, but found from Minnesota to Florida.</p>
+
+<p class="negative"><b>87. Live Oak</b> (<i>Quercus virens</i>) (Maul Oak). Medium- to
+large-sized tree. Grows from Maryland to the Gulf<span class='pagenum'><a name="Page_76" id="Page_76">[76]</a></span>
+of Mexico, and often attains a height of 60 feet and
+4 feet in diameter. The wood is hard, strong, and
+durable, but of rather rapid growth, therefore not
+as good quality as <i>Quercus alba</i>. The live oak of
+Florida is now reserved by the United States Government
+for Naval purposes. Used for mauls and mallets,
+tool handles, etc., and locally for construction.
+Scattered along the coast from Maryland to Texas.</p>
+
+<p class="negative"><b>88. Live Oak</b> (<i>Quercus chrysolepis</i>) (Maul Oak, Valparaiso
+Oak). Medium- to small-sized tree. California.</p>
+
+
+<h4>OSAGE ORANGE</h4>
+
+<p class="negative"><b>89. Osage Orange</b> (<i>Maclura aurantiaca</i>) (Bois d'Arc).
+A small-sized tree of fairly rapid growth. Wood
+very heavy, exceedingly hard, strong, not tough, of
+moderately coarse texture, and very durable and
+elastic. Sapwood yellow, heartwood brown on the
+end face, yellow on the longitudinal faces, soon
+turning grayish brown if exposed. It shrinks considerably
+in drying, but once dry it stands unusually
+well. Much used for wheel stock, and wagon framing;
+it is easily split, so is unfit for wheel hubs, but is very
+suitable for wheel spokes. It is considered one of
+the timbers likely to supply the place of black locust
+for insulator pins on telegraph poles. Seems too
+little appreciated; it is well suited for turned ware
+and especially for woodcarving. Used for spokes,
+insulator pins, posts, railway ties, wagon framing,
+turnery, and woodcarving. Scattered through the
+rich bottoms of Arkansas and Texas.</p>
+
+
+<h4>PAPAW</h4>
+
+<p class="negative"><b>90. Papaw</b> (<i>Asimina triloba</i>) (Custard Apple). Small-sized
+tree, often only a shrub, Heartwood pale,
+yellowish green, sapwood lighter color. Wood light,
+soft, coarse-grained, and spongy. Not used to any
+extent in manufacture. Occurs in eastern and central
+Pennsylvania, west as far as Michigan and Kansas,
+and south to Florida and Texas. Often forming<span class='pagenum'><a name="Page_77" id="Page_77">[77]</a></span>
+dense thickets in the lowlands bordering the Mississippi
+River.</p>
+
+
+<h4>PERSIMMON</h4>
+
+<p class="negative"><b>91. Persimmon</b> (<i>Diospyros Virginiana</i>). Small to medium-sized
+tree. Wood very heavy, and hard, strong and
+tough; resembles hickory, but is of finer texture and
+elastic, but liable to split in working. The broad
+sapwood cream color, the heartwood brown, sometimes
+almost black. The persimmon is the Virginia
+date plum, a tree of 30 to 50 feet high, and 18 to 20
+inches in diameter; it is noted chiefly for its fruit,
+but it produces a wood of considerable value. Used
+in turnery, for wood engraving, shuttles, bobbins,
+plane stock, shoe lasts, and largely as a substitute
+for box (<i>Buxus sempervirens</i>)&mdash;especially the black
+or Mexican variety,&mdash;also used for pocket rules and
+drawing scales, for flutes and other wind instruments.
+Common, and best developed in the lower
+Ohio Valley, but occurs from New York to Texas
+and Missouri.</p>
+
+
+<h4>POPLAR (See also Tulip Wood)</h4>
+
+<p>Wood light, very soft, not strong, of fine texture, and
+whitish, grayish to yellowish color, usually with a satiny
+luster. The wood shrinks moderately (some cross-grained
+forms warp excessively), but checks very little in seasoning;
+is easily worked, but is not durable. Used in cooperage,
+for building and furniture lumber, for crates and
+boxes (especially cracker boxes), for woodenware, and
+paper pulp.</p>
+
+<p class="negative"><b>92. Cottonwood</b> (<i>Populus monilifera</i>, var. <i>angulata</i>) (Carolina
+Poplar). Large-sized tree, forms considerable
+forests along many of the Western streams, and
+furnishes most of the cottonwood of the market.
+Heartwood dark brown, sapwood nearly white. Wood
+light, soft, not strong, and close-grained (see <a href="#Fig_14">Fig.
+14</a>). Mississippi Valley and West. New England
+to the Rocky Mountains.<span class='pagenum'><a name="Page_78" id="Page_78">[78]</a></span></p>
+
+<p class="negative"><b>93. Cottonwood</b> (<i>Populus fremontii</i> var. <i>wislizeni</i>). Medium-
+to large-sized tree. Common. Wood in its
+quality and uses similiar to the preceding, but not
+so valuable. Texas to California.</p>
+
+<div class="figcenter" style="width: 400px;"><p class="anchor"><a name="Fig_14" id="Fig_14"></a></p>
+<img src="images/fig14.jpg" width="400" height="508" alt="A Large Cottonwood" title="A Large Cottonwood" />
+
+<p class="caption" style="text-align: center">Fig. 14. A Large Cottonwood. One of the Associates of Red Gum.</p>
+</div>
+
+<p class="negative"><b>94. Black Cottonwood</b> (<i>Populus trichocarpa</i> var. <i>heterophylla</i>)
+(Swamp Cottonwood, Downy Poplar). The
+largest deciduous tree of Washington. Very common.<span class='pagenum'><a name="Page_79" id="Page_79">[79]</a></span>
+Heartwood dull brown, sapwood lighter brown. Wood
+soft, close-grained. Is now manufactured into lumber
+in the West and South, and used in interior finish
+of buildings. Northern Rocky Mountains and
+Pacific region.</p>
+
+<p class="negative"><b>95. Poplar</b> (<i>Populus grandidentata</i>) (Large-Toothed Aspen).
+Medium-sized tree. Heartwood light brown,
+sapwood nearly white. Wood soft and close-grained,
+neither strong nor durable. Chiefly used for wood
+pulp. Maine to Minnesota and southward along
+the Alleghanies.</p>
+
+<p class="negative"><b>96. White Poplar</b> (<i>Populus alba</i>) (Abele-Tree). Small
+to medium-sized tree. Wood in its quality and uses
+similar to the preceding. Found principally along
+banks of streams, never forming forests. Widely
+distributed in the United States.</p>
+
+<p class="negative"><b>97. Lombardy Poplar</b> (<i>Populus nigra italica</i>). Medium-
+to large-sized tree. This species is the first ornamental
+tree introduced into the United States, and
+originated in Afghanistan. Does not enter into the
+markets. Widely planted in the United States.</p>
+
+<p class="negative"><b>98. Balsam</b> (<i>Populus balsamifera</i>) (Balm of Gilead, Tacmahac).
+Medium- to large-sized tree. Heartwood light
+brown, sapwood nearly white. Wood light, soft,
+not strong, close-grained. Used extensively in the
+manufacture of paper pulp. Common all along the
+northern boundary of the United States.</p>
+
+<p class="negative"><b>99. Aspen</b> (<i>Populus tremuloides</i>) (Quaking Aspen). Small
+to medium-sized tree, often forming extensive forests,
+and covering burned areas. Heartwood light brown,
+sapwood nearly white. Wood light, soft, close-grained,
+neither strong nor durable. Chiefly used
+for woodenware, cooperage, and paper pulp. Maine
+to Washington and northward, and south in the
+western mountains to California and New Mexico.</p>
+
+
+<h4>RED GUM (See Gum)<span class='pagenum'><a name="Page_80" id="Page_80">[80]</a></span></h4>
+
+
+<h4>SASSAFRAS</h4>
+
+<p class="negative2"><b>100. Sassafras</b> (<i>Sassafras sassafras</i>). Medium-sized tree,
+largest in the lower Mississippi Valley. Wood light,
+soft, not strong, brittle, of coarse texture, durable
+in contact with the soil. The sapwood yellow, the
+heartwood orange brown. Used to some extent in
+slack cooperage, for skiff- and boatbuilding, fencing,
+posts, sills, etc. Occurs from New England to Texas
+and from Michigan to Florida.</p>
+
+
+<h4>SOUR GUM (See Gum)</h4>
+
+<h4>SOURWOOD</h4>
+
+<p class="negative2"><b>101. Sourwood</b> (<i>Oxydendrum arboreum</i>) (Sorrel-Tree). A
+slender tree, reaching the maximum height of 60 feet.
+Heartwood reddish brown, sapwood lighter color.
+Wood heavy, hard, strong, close-grained, and takes
+a fine polish. Ranges from Pennsylvania, along the
+Alleghanies, to Florida and Alabama, westward through
+Ohio to southern Indiana and southward through
+Arkansas and Louisiana to the Coast.</p>
+
+
+<h4>SWEET GUM (See Gum)</h4>
+
+<h4>SYCAMORE</h4>
+
+<p class="negative2"><b>102. Sycamore</b> (<i>Platanus occidentalis</i>) (Buttonwood, Button-Ball
+Tree, Plane Tree, Water Beech). A large-sized
+tree, of rapid growth. One of the largest deciduous
+trees of the United States, sometimes attaining a
+height of 100 feet. It produces a timber that is moderately
+heavy, quite hard, stiff, strong, and tough,
+usually cross-grained; of coarse texture, difficult to
+split and work, shrinks moderately, but warps and
+checks considerably in seasoning, but stands well,
+and is not considered durable for outside work, or in
+contact with the soil. It has broad medullary rays,
+and much of the timber has a beautiful figure. It
+is used in slack cooperage, and quite extensively for<span class='pagenum'><a name="Page_81" id="Page_81">[81]</a></span>
+drawers, backs, and bottoms, etc., in furniture work.
+It is also used for cabinet work, for tobacco boxes,
+crates, desks, flooring, furniture, ox-yokes, butcher
+blocks, and also for finishing lumber, where it has too
+long been underrated. Common and largest in the
+Ohio and Mississippi Valleys, at home in nearly all
+parts of the eastern United States.</p>
+
+<p class="negative2"><b>103. Sycamore</b> (<i>Platanus racemosa</i>). The California
+species, resembling in its wood the Eastern form.
+Not used to any great extent.</p>
+
+
+<h4>TULIP TREE</h4>
+
+<p class="negative2"><b>104. Tulip Tree</b> (<i>Liriodendron tulipifera</i>) (Yellow Poplar,
+Tulip Wood, White Wood, Canary Wood, Poplar,
+Blue Poplar, White Poplar, Hickory Poplar). A
+medium- to large-sized tree, does not form forests,
+but is quite common, especially in the Ohio basin.
+Wood usually light, but varies in weight, it is soft,
+tough, but not strong, of fine texture, and yellowish
+color. The wood shrinks considerably, but seasons
+without much injury, and works and stands extremely
+well. Heartwood light yellow or greenish brown,
+the sapwood is thin, nearly white, and decays rapidly.
+The heartwood is fairly durable when exposed to the
+weather or in contact with the soil. It bends readily
+when steamed, and takes stain and paint well. The
+mature forest-grown tree has a long, straight, cylindrical
+bole, clear of branches for at least two thirds of
+its length, surmounted by a short, open, irregular
+crown. When growing in the open, the tree maintains
+a straight stem, but the crown extends almost
+to the ground, and is of conical shape. Yellow poplar,
+or tulip wood, ordinarily grows to a height of from
+100 to 125 feet, with a diameter of from 3 to 6 feet,
+and a clear length of about 70 feet. Trees have been
+found 190 feet high and ten feet in diameter. Used
+in cooperage, for siding, for panelling and finishing
+lumber in houses, car- and shipbuilding, for sideboards,
+panels of wagons and carriages, for aeroplanes,<span class='pagenum'><a name="Page_82" id="Page_82">[82]</a></span>
+for automobiles, also in the manufacture of furniture
+farm implements, machinery, for pump logs, and
+almost every kind of common woodenware, boxes
+shelving, drawers, etc., etc. Also in the manufacture
+of toys, culinary woodenware, and backing for veneer.
+It is in great demand throughout the vehicle and implement
+trade, and also makes a fair grade of wood
+pulp. In fact the tulip tree is one of the most useful
+of woods throughout the woodworking industry
+of this country. Occurs from New England to Missouri
+and southward to Florida.</p>
+
+
+<h4>TUPELO (See Gum)</h4>
+
+<h4>WAAHOO</h4>
+
+<p class="negative2"><b>105. Waahoo</b> (<i>Evonymus atropurpureus</i>). (Burning Bush,
+Spindle Tree). A small-sized tree. Wood white,
+tinged with orange; heavy, hard, tough, and close-grained,
+works well and stands well. Used principally
+for arrows and spindles. Widely distributed.
+Usually a shrub six to ten feet high, becoming a tree
+only in southern Arkansas and Oklahoma.</p>
+
+
+<h4>WALNUT</h4>
+
+<p class="negative2"><b>106. Black Walnut</b> (<i>Juglans nigra</i>) (Walnut). A large,
+beautiful, and quickly-growing tree, about 60 feet and
+upwards in height. Wood heavy, hard, strong, of
+coarse texture, very durable in contact with the soil.
+The narrow sapwood whitish, the heartwood dark,
+rich, chocolate brown, sometimes almost black; aged
+trees of fine quality bring fancy prices. The wood
+shrinks moderately in seasoning, works well and stands
+well, and takes a fine polish. It is quite handsome,
+and has been for a long time the favorite wood for
+cabinet and furniture making. It is used for gun-stocks,
+fixtures, interior decoration, veneer, panelling,
+stair newells, and all classes of work demanding
+a high priced grade of wood. Black walnut is
+a large tree with stout trunk, of rapid growth, and<span class='pagenum'><a name="Page_83" id="Page_83">[83]</a></span>
+was formerly quite abundant throughout the Alleghany
+region. Occurs from New England to Texas,
+and from Michigan to Florida. Not common.</p>
+
+
+<h4>WHITE WALNUT (See Butternut)</h4>
+
+
+<h4>WHITE WOOD (See Tulip and also Basswood)</h4>
+
+
+<h4>WHITE WILLOW</h4>
+
+<p class="negative2"><b>107. White Willow</b> (<i>Salix alba</i> var. <i>vitellina</i>) (Willow,
+Yellow Willow, Blue Willow). The wood is very
+soft, light, flexible, and fairly strong, is fairly durable
+in contact with the soil, works well and stands well
+when seasoned. Medium-sized tree, characterized
+by a short, thick trunk, and a large, rather irregular
+crown composed of many branches. The size of
+the tree at maturity varies with the locality. In
+the region where it occurs naturally, a height of 70
+to 80 feet, and a diameter of three to four feet are
+often attained. When planted in the Middle West,
+a height of from 50 to 60 feet, and a diameter of one
+and one-half to two feet are all that may be expected.
+When closely planted on moist soil, the tree forms a
+tall, slender stem, well cleared branches. Is widely
+naturalized in the United States. It is used in cooperage,
+for woodenware, for cricket and baseball bats,
+for basket work, etc. Charcoal made from the wood
+is used in the manufacture of gunpowder. It has
+been generally used for fence posts on the Northwestern
+plains, because of scarcity of better material.
+Well seasoned posts will last from four to seven
+years. Widely distributed throughout the United
+States.</p>
+
+<p class="negative2"><b>108. Black Willow</b> (<i>Salix nigra</i>). Small-sized tree.
+Heartwood light reddish brown, sapwood nearly
+white. Wood soft, light, not strong, close-grained,
+and very flexible. Used in basket making, etc.
+Ranges from New York to Rocky Mountains and
+southward to Mexico.<span class='pagenum'><a name="Page_84" id="Page_84">[84]</a></span></p>
+
+<p class="negative2"><b>109. Shining Willow</b> (<i>Salix lucida</i>). A small-sized tree.
+Wood in its quality and uses similiar to the preceding.
+Ranges from Newfoundland to Rocky Mountains
+and southward to Pennsylvania and Nebraska.</p>
+
+<p class="negative2"><b>110. Perch Willow</b> (<i>Salix amygdaloides</i>) (Almond-leaf
+Willow). Small to medium-sized tree. Heartwood
+light brown, sapwood lighter color. Wood light,
+soft, flexible, not strong, close-grained. Uses similiar
+to the preceding. Follows the water courses and
+ranges across the continent; less abundant in New
+England than elsewhere. Common in the West.</p>
+
+<p class="negative2"><b>111. Long-Leaf Willow</b> (<i>Salix fluviatilis</i>) (Sand Bar Willow).
+A small-sized tree. Ranges from the Arctic
+Circle to Northern Mexico.</p>
+
+<p class="negative2"><b>112. Bebb Willow</b> (<i>Salix bebbiana</i> var. <i>rostrata</i>). A small-sized
+tree. More abundant in British America than
+in the United States, where it ranges southward to
+Pennsylvania and westward to Minnesota.</p>
+
+<p class="negative2"><b>113. Glaucous Willow</b> (<i>Salix discolor</i>) (Pussy Willow).
+A small-sized tree. Common along the banks of
+streams, and ranges from Nova Scotia to Manitoba,
+and south to Delaware; west to Indiana and northwestern
+Missouri.</p>
+
+<p class="negative2"><b>114. Crack Willow</b> (<i>Salix fragilis</i>). A medium to large-sized
+tree. Wood is very soft, light, very flexible
+and fairly strong, is fairly durable in contact with
+the soil, works well and stands well. Used principally
+for basket making, hoops, etc., and to produce
+charcoal for gunpowder. Very common, and
+widely distributed in the United States.</p>
+
+<p class="negative2"><b>115. Weeping Willow</b> (<i>Salix babylonica</i>). Medium- to
+large-sized tree. Wood similiar to <i>Salix nigra</i>, but
+not so valuable. Mostly an ornamental tree. Originally
+came from China. Widely planted in the
+United States.<span class='pagenum'><a name="Page_85" id="Page_85">[85]</a></span></p>
+
+
+<h4>YELLOW WOOD</h4>
+
+<p class="negative2"><b>116. Yellow Wood</b> (<i>Cladrastis lutea</i>) (Virgilia). A small
+to medium-sized tree. Wood yellow to pale brown,
+heavy, hard, close-grained and strong. Not used
+to much extent in manufacturing. Not common.
+Found principally on the limestone cliffs of Kentucky,
+Tennessee, and North Carolina.</p>
+
+
+
+<h3 style="padding-bottom: 0em"><a name="SECTION_IV" id="SECTION_IV"></a>SECTION IV<span class='pagenum'><a name="Page_86" id="Page_86">[86]</a></span></h3>
+
+<h2>GRAIN, COLOR, ODOR, WEIGHT,
+AND FIGURE IN WOOD</h2>
+
+
+<h3 style="padding-top: 0em">DIFFERENT GRAINS OF WOOD</h3>
+
+<p><span class="smcap">The</span> terms "fine-grained," "coarse-grained," "straight-grained,"
+and "cross-grained" are frequently applied in
+the trade. In common usage, wood is coarse-grained if
+its annual rings are wide; fine-grained if they are narrow.
+In the finer wood industries a fine-grained wood is capable
+of high polish, while a coarse-grained wood is not, so
+that in this latter case the distinction depends chiefly on
+hardness, and in the former on an accidental case of slow
+or rapid growth. Generally if the direction of the wood
+fibres is parallel to the axis of the stem or limb in which
+they occur, the wood is straight-grained; but in many
+cases the course of the fibres is spiral or twisted around
+the tree (as shown in <a href="#Fig_15">Fig. 15</a>), and sometimes commonly
+in the butts of gum and cypress, the fibres of several layers
+are oblique in one direction, and those of the next series
+of layers are oblique in the opposite direction. (As shown
+in <a href="#Fig_16">Fig. 16</a> the wood is cross or twisted grain.) Wavy-grain
+in a tangential plane as seen on the radial section is
+illustrated in <a href="#Fig_17">Fig. 17</a>, which represents an extreme case
+observed in beech. This same form also occurs on the
+radial plane, causing the tangential section to appear wavy
+or in transverse folds.</p>
+
+<p>When wavy grain is fine (<i>i.e.</i>, the folds or ridges small
+but numerous) it gives rise to the "curly" structure
+frequently seen in maple. Ordinarily, neither wavy,
+spiral, nor alternate grain is visible on the cross-section;
+its existence often escapes the eye even on smooth, longitudinal
+faces in the sawed material, so that the only<span class='pagenum'><a name="Page_87" id="Page_87">[87]</a></span>
+guide to their discovery lies in splitting the wood in two,
+in the two normal plains.</p>
+
+<table summary="illos">
+<tr><td><div class="figcenter" style="width: 150px;"><p class="anchor"><a name="Fig_15" id="Fig_15"></a></p>
+<img src="images/fig15.jpg" width="150" height="322" alt="Spiral Grain" title="Spiral Grain" />
+</div>
+
+<p class="caption" style="margin-left: 2em; margin-right: 2em">Fig. 15. Spiral Grain. Season checks, after removal of bark, indicate the
+direction of the fibres or grain of the wood.</p>
+</td>
+
+<td style="padding-left: 3em; padding-right: 3em"><div class="figcenter" style="width: 322px;"><p class="anchor"><a name="Fig_16" id="Fig_16"></a></p>
+<img src="images/fig16.jpg" width="322" height="342" alt="Alternating Spiral Grain in Cypress" title="Alternating Spiral Grain in Cypress" />
+
+<p class="caption">Fig. 16. Alternating Spiral Grain in Cypress. Side and end view of same
+piece. When the bark was at <i>o</i>, the grain of this piece was straight.
+From that time, each year it grew more oblique in one direction,
+reaching a climax at <i>a</i>, and then turned back in the opposite direction.
+These alternations were repeated periodically, the bark sharing in
+these changes.</p>
+</div></td></tr>
+</table>
+
+<p>Generally the surface of the wood under the bark, and
+therefore also that of any layer in the interior, is not uniform
+and smooth, but is channelled and pitted by numerous
+depressions, which differ greatly in size and form.
+Usually, any one depression or elevation is restricted to
+one or few annual layers (<i>i.e.</i>, seen only in one or few rings)
+and is then lost, being compensated (the surface at the
+particular spot evened up) by growth. In some woods,
+however, any depression or elevation once attained grows
+from year to year and reaches a maximum size, which is
+maintained for many years, sometimes throughout life.
+In maple, where this tendency to preserve any particular
+contour is very great, the depressions and elevations are<span class='pagenum'><a name="Page_88" id="Page_88">[88]</a></span>
+usually small (commonly less than one-eighth inch) but
+very numerous.</p>
+
+<p>On tangent boards of such wood, the sections, pits, and
+prominences appear as circlets, and give rise to the beautiful
+"bird's eye" or "landscape" structure. Similiar structures
+in the burls of black ash, maple, etc., are frequently
+due to the presence of dormant buds, which cause the
+surface of all the layers through which they pass to be
+covered by small conical elevations, whose cross-sections
+on the sawed board appear as irregular circlets or islets,
+each with a dark speck, the section of the pith or "trace"
+of the dormant bud in the center.</p>
+
+<div class="figcenter" style="width: 300px;"><p class="anchor"><a name="Fig_17" id="Fig_17"></a></p>
+<img src="images/fig17.jpg" width="300" height="287" alt="Wavy Grain in Beech" title="Wavy Grain in Beech" />
+
+<p class="caption" style="text-align: center">Fig. 17. Wavy Grain in Beech (<i>after Nordlinger</i>).</p>
+</div>
+
+<div class="figright" style="width: 120px;"><p class="anchor"><a name="Fig_18" id="Fig_18"></a></p>
+<img src="images/fig18.jpg" width="120" height="257" alt="Section of Wood" title="Section of Wood" />
+</div>
+
+
+
+<p>In the wood of many broad-leaved trees the wood fibres
+are much longer when full grown than when they are first
+formed in the cambium or growing zone. This causes
+the tips of each fibre to crowd in between the fibres above
+and below, and leads to an irregular interlacement of these
+fibres, which adds to the toughness, but reduces the cleavability
+of the wood. At the juncture of the limb and stem
+the fibres on the upper and lower sides of the limb behave<span class='pagenum'><a name="Page_89" id="Page_89">[89]</a></span>
+differently. On the lower side they run from the stem
+into the limb, forming an uninterrupted strand or tissue
+and a perfect union. On the upper side the fibres bend
+aside, are not continuous into the
+limb, and hence the connection is
+not perfect (see <a href="#Fig_18">Fig. 18</a>). Owing
+to this arrangement of the fibres,
+the cleft made in splitting never
+runs into the knot if started on
+the side above the limb, but is
+apt to enter the knot if started
+below, a fact well understood in
+woodcraft. When limbs die, decay,
+and break off, the remaining stubs
+are surrounded, and may finally
+be covered by the growth of the
+trunk and thus give rise to the annoying
+"dead" or "loose" knots.</p>
+
+<p class="caption" style="margin-left: 4em">Fig. 18. Section of Wood
+showing Position of the
+Grain at Base of a Limb.
+P, pith of both stem and
+limb; 1-7, seven yearly
+layers of wood; <i>a</i>, <i>b</i>, knot
+or basal part of a limb
+which lived for four years,
+then died and broke off
+near the stem, leaving the
+part to the left of <i>a</i>, <i>b</i>, a
+"sound" knot, the part
+to the right a "dead"
+knot, which would soon
+be entirely covered by
+the growing stem.</p>
+
+<h4>COLOR AND ODOR
+OF WOOD</h4>
+
+<p>Color, like structure, lends
+beauty to the wood, aids in its
+identification, and is of great value
+in the determination of its quality.
+If we consider only the heartwood,
+the black color of the persimmon,
+the dark brown of the walnut, the
+light brown of the white oaks, the
+reddish brown of the red oaks,
+the yellowish white of the tulip
+and poplars, the brownish red of
+the redwood and cedars, the yellow
+of the papaw and sumac, are all reliable
+marks of distinction and color.
+Together with luster and weight,
+they are only too often the only features depended upon
+in practice. Newly formed wood, like that of the outer few
+rings, has but little color. The sapwood generally is light,<span class='pagenum'><a name="Page_90" id="Page_90">[90]</a></span>
+and the wood of trees which form no heartwood changes
+but little, except when stained by forerunners of disease.</p>
+
+<p>The different tints of colors, whether the brown of oak,
+the orange brown of pine, the blackish tint of walnut, or
+the reddish cast of cedar, are due to pigments, while the
+deeper shade of the summer-wood bands in pine, cedar,
+oak, or walnut is due to the fact that the wood being
+denser, more of the colored wood substance occurs on a
+given space, <i>i.e.</i>, there is more colored matter per square
+inch. Wood is translucent, a thin disk of pine permitting
+light to pass through quite freely. This translucency
+affects the luster and brightness of lumber.</p>
+
+<p>When lumber is attacked by fungi, it becomes more
+opaque, loses its brightness, and in practice is designated
+"dead," in distinction to "live" or bright timber. Exposure
+to air darkens all wood; direct sunlight and occasional
+moistening hasten this change, and cause it to
+penetrate deeper. Prolonged immersion has the same
+effect, pine wood becoming a dark gray, while oak changes
+to a blackish brown.</p>
+
+<p>Odor, like color, depends on chemical compounds,
+forming no part of the wood substance itself. Exposure
+to weather reduces and often changes the odor,
+but a piece of long-leaf pine, cedar, or camphor wood exhales
+apparently as much odor as ever when a new surface
+is exposed. Heartwood is more odoriferous than sapwood.
+Many kinds of wood are distinguished by strong and
+peculiar odors. This is especially the case with camphor,
+cedar, pine, oak, and mahogany, and the list would comprise
+every kind of wood in use were our sense of smell
+developed in keeping with its importance.</p>
+
+<p>Decomposition is usually accompanied by pronounced
+odors. Decaying poplar emits a disagreeable odor, while
+red oak often becomes fragrant, its smell resembling that
+of heliotrope.<span class='pagenum'><a name="Page_91" id="Page_91">[91]</a></span></p>
+
+
+<h4>WEIGHT OF WOOD</h4>
+
+<p>A small cross-section of wood (as in <a href="#Fig_19">Fig. 19</a>) dropped
+into water sinks, showing that the substance of which
+wood fibre or wood is built up is heavier than water. By
+immersing the wood successively in
+heavier liquids, until we find a liquid
+in which it does not sink, and comparing
+the weight of the same with water,
+we find that wood substance is about
+1.6 times as heavy as water, and that
+this is as true of poplar as of oak or
+pine.</p>
+
+<div class="figright" style="width: 200px;"><p class="anchor"><a name="Fig_19" id="Fig_19"></a></p>
+<img src="images/fig19.jpg" width="200" height="192" alt="Cross-section
+of a Group of Wood
+Fibres" title="Cross-section
+of a Group of Wood
+Fibres" />
+
+<p class="caption">Fig. 19. Cross-section
+of a Group of Wood
+Fibres (Highly
+Magnified.)</p>
+</div>
+
+<div class="figleft" style="width: 100px;"><p class="anchor"><a name="Fig_20" id="Fig_20"></a></p>
+<img src="images/fig20.jpg" width="100" height="380" alt="Isolated
+Fibres of
+Wood" title="Isolated
+Fibres of
+Wood" />
+
+<p class="caption">Fig. 20.
+Isolated
+Fibres of
+Wood.</p>
+</div>
+
+<p>Separating a single cell (as shown in
+<a href="#Fig_20">Fig. 20</a>, <i>a</i>), drying and then dropping
+it into water, it floats. The air-filled
+cell cavity or interior reduces its weight,
+and, like an empty corked bottle, it weighs less than the
+water. Soon, however, water soaks into the cell, when it
+fills up and sinks. Many such cells grown together,
+as in a block of wood, when all or most
+of them are filled with water, will float as long
+as the majority of them are empty or only
+partially filled. This is why a green, sappy pine
+pole soon sinks in "driving" (floating down
+stream). Its cells are largely filled before it is
+thrown in, and but little additional water suffices
+to make its weight greater than that of the
+water. In a good-sized white pine log, composed
+chiefly of empty cells (heartwood), the water
+requires a very long time to fill up the cells (five
+years would not suffice to fill them all), and
+therefore the log may float for many months.
+When the wall of the wood fibre is very thick
+(five eighths or more of the volume, as in <a href="#Fig_20">Fig.
+20</a>, <i>b</i>), the fibre sinks whether empty or filled.
+This applies to most of the fibres of the dark
+summer-wood bands in pines, and to the compact fibres
+of oak or hickory, and many, especially tropical woods,<span class='pagenum'><a name="Page_92" id="Page_92">[92]</a></span>
+have such thick-walled cells and so little empty or air space
+that they never float.</p>
+
+
+
+<p>Here, then, are the two main factors of weight in wood;
+the amount of cell wall or wood substance constant for
+any given piece, and the amount of water contained in
+the wood, variable even in the standing tree, and only in
+part eliminated in drying.</p>
+
+<p>The weight of the green wood of any species varies
+chiefly as a second factor, and is entirely misleading, if
+the relative weight of different kinds is sought. Thus
+some green sticks of the otherwise lighter cypress and
+gum sink more readily than fresh oak.</p>
+
+<p>The weight of sapwood or the sappy, peripheral part
+of our common lumber woods is always great, whether
+cut in winter or summer. It rarely falls much below
+forty-five pounds, and commonly exceeds fifty-five pounds
+to the cubic foot, even in our lighter wooded species. It
+follows that the green wood of a sapling is heavier than
+that of an old tree, the fresh wood from a disk of the upper
+part of a tree is often heavier than that of the lower part,
+and the wood near the bark heavier than that nearer the
+pith; and also that the advantage of drying the wood
+before shipping is most important in sappy and light
+kinds.</p>
+
+<p>When kiln-dried, the misleading moisture factor of
+weight is uniformly reduced, and a fair comparison possible.
+For the sake of convenience in comparison, the
+weight of wood is expressed either as the weight per cubic
+foot, or, what is still more convenient, as specific weight
+or density. If an old long-leaf pine is cut up (as shown
+in <a href="#Fig_21">Fig. 21</a>) the wood of disk No. 1 is heavier than that of
+disk No. 2, the latter heavier than that of disk No. 3, and
+the wood of the top disk is found to be only about three
+fourths as heavy as that of disk No. 1. Similiarly, if disk
+No. 2 is cut up, as in the figure, the specific weight of the
+different parts is:</p>
+
+<ul style="margin-left: 30%">
+<li style="padding-left: 2em"><i>a</i>, about 0.52</li>
+<li style="padding-left: 2em"><i>b</i>, about 0.64</li>
+<li style="padding-left: 2em"><i>c</i>, about 0.67</li>
+<li><i>d</i>, <i>e</i>, <i>f</i>, &nbsp;about 0.65</li></ul>
+
+
+
+<p style="text-indent: 0em">showing that in this disk at least the wood formed during<span class='pagenum'><a name="Page_93" id="Page_93">[93]</a></span>
+the many years' growth, represented in piece <i>a</i>, is much
+lighter than that of former years. It also shows that the
+best wood is the middle part, with its large proportion of
+dark summer bands.</p>
+
+<div class="figcenter" style="width: 300px;"><p class="anchor"><a name="Fig_21" id="Fig_21"></a></p>
+<img src="images/fig21.jpg" width="300" height="320" alt="Orientation of Wood Samples" title="Orientation of Wood Samples" />
+
+<p class="caption" style="text-align: center">Fig. 21. Orientation of Wood Samples.</p>
+</div>
+
+<p>Cutting up all disks in the same way, it will be found
+that the piece <i>a</i> of the first disk is heavier than the piece
+<i>a</i> of the fifth, and that piece <i>c</i> of the first disk excels the
+piece <i>c</i> of all the other disks. This shows that the wood
+grown during the same number of years is lighter in the
+upper parts of the stem; and if the disks are smoothed on
+the radial surfaces and set up one on top of the other in
+their regular order, for the sake of comparison, this decrease
+in weight will be seen to be accompanied by a decrease
+in the amount of summer-wood. The color effect
+of the upper disks is conspicuously lighter. If our old
+pine had been cut one hundred and fifty years ago,
+before the outer, lighter wood was laid on, it is evident
+that the weight of the wood of any one disk would have
+been found to increase from the center outward, and no
+subsequent decrease could have been observed.<span class='pagenum'><a name="Page_94" id="Page_94">[94]</a></span></p>
+
+<p>In a thrifty young pine, then, the wood is heavier from
+the center outward, and lighter from below upward; only
+the wood laid on in old age falls in weight below the average.
+The number of brownish bands of summer-wood are a
+direct indication of these differences. If an old oak is
+cut up in the same manner, the butt cut is also found
+heaviest and the top lightest, but, unlike the disk of pine,
+the disk of oak has its firmest wood at the center, and each
+successive piece from the center outward is lighter than
+its neighbor.</p>
+
+<p>Examining the pieces, this difference is not as readily
+explained by the appearance of each piece as in the case
+of pine wood. Nevertheless, one conspicuous point appears
+at once. The pores, so very distinct in oak, are
+very minute in the wood near the center, and thus the
+wood is far less porous.</p>
+
+<p>Studying different trees, it is found that in the pines,
+wood with narrow rings is just as heavy as and often heavier
+than the wood with wider rings; but if the rings are unusually
+narrow in any part of the disk, the wood has a
+lighter color; that is, there is less summer-wood and therefore
+less weight.</p>
+
+<p>In oak, ash, or elm trees of thrifty growth, the rings,
+fairly wide (not less than one-twelfth inch), always form
+the heaviest wood, while any piece with very narrow rings
+is light. On the other hand, the weight of a piece of hard
+maple or birch is quite independent of the width of its
+rings.</p>
+
+<p>The bases of limbs (knots) are usually heavy, very
+heavy in conifers, and also the wood which surrounds
+them, but generally the wood of the limbs is lighter than
+that of the stem, and the wood of the roots is the
+lightest.</p>
+
+<p>In general, it may be said that none of the native woods
+in common use in this country are when dry as heavy as
+water, <i>i.e.</i>, sixty-two pounds to the cubic foot. Few exceed
+fifty pounds, while most of them fall below forty
+pounds, and much of the pine and other coniferous wood
+weigh less than thirty pounds per cubic foot. The weight
+of the wood is in itself an important quality. Weight<span class='pagenum'><a name="Page_95" id="Page_95">[95]</a></span>
+assists in distinguishing maple from poplar. Lightness
+coupled with great strength and stiffness recommends
+wood for a thousand different uses. To a large extent
+weight predicates the strength of the wood, at least in the
+same species, so that a heavy piece of oak will exceed in
+strength a light piece of the same species, and in pine it
+appears probable that, weight for weight, the strength of
+the wood of various pines is nearly equal.</p>
+
+<p class="center"><span class="smcap">Weight of Kiln-dried Wood of Different Species</span></p>
+
+<table summary="weight of kiln-dried wood" cellpadding="6" class="kilnwood">
+
+<tr><td class="centered" rowspan="3" style="border-left: 0">Species</td><td class="centered" colspan="3">Approximate</td></tr>
+<tr><td class="centered" rowspan="2">Specific<br /> Weight</td><td class="centered" colspan="2">Weight of</td></tr>
+
+<tr><td class="centered">1<br />Cubic<br />Foot</td><td class="centered">1,000<br />Feet<br />Lumber</td></tr>
+
+<tr><td class="tableentry">(<i>a</i>) Very Heavy Woods:
+  Hickory, Oak, Persimmon, Osage Orange,
+  Black Locust, Hackberry, Blue Beech,
+  best of Elm and Ash</td><td class="values">0.70-0.80</td><td class="values">42-48</td><td class="values">3,700</td></tr>
+
+<tr><td class="tableentry">(<i>b</i>) Heavy Woods
+  Ash, Elm, Cherry, Birch, Maple, Beech,
+  Walnut, Sour Gum, Coffee Tree, Honey
+  Locust, best of Southern Pine and
+  Tamarack</td><td class="values">0.60-0.70</td><td class="values">36-42</td><td class="values">3,200</td></tr>
+
+<tr><td class="tableentry">(<i>c</i>) Woods of Medium Weight:
+  Southern Pine, Pitch Pine, Tamarack,
+  Douglas Spruce, Western Hemlock,
+  Sweet Gum, Soft Maple, Sycamore,
+  Sassafras, Mulberry, light grades of
+  Birch and Cherry</td><td class="values">0.50-0.60</td><td class="values">30-36</td><td class="values">2,700</td></tr>
+
+<tr><td class="tableentry">(<i>d</i>) Light Woods:
+  Norway and Bull Pine, Red Cedar,
+  Cypress, Hemlock, the Heavier Spruces
+  and Firs, Redwood, Basswood, Chestnut,
+  Butternut, Tulip, Catalpa, Buckeye,
+  heavier grades of Poplar</td><td class="values">0.40-0.50</td><td class="values">24-30</td><td class="values">2,200</td></tr>
+
+<tr><td class="tableentry">(<i>e</i>) Very Light Woods:
+  White Pine, Spruce, Fir, White Cedar,
+  Poplar</td><td class="values">0.30-0.40</td><td class="values">18-24</td><td class="values">1,800</td></tr>
+</table>
+
+
+<h4>"FIGURE" IN WOOD<span class='pagenum'><a name="Page_96" id="Page_96">[96]</a></span></h4>
+
+<p>Many theories have been propounded as to the cause
+of "figure" in timber; while it is true that all timber
+possesses "figure" in some degree, which is more noticeable
+if it be cut in certain ways, yet there are some woods in
+which it is more conspicuous than in others, and which
+for cabinet or furniture work are much appreciated, as
+it adds to the value of the work produced.</p>
+
+<p>The characteristic "figure" of oak is due to the broad
+and deep medullary rays so conspicuous in this timber,
+and the same applies to honeysuckle. Figure due to the
+same cause is found in sycamore and beech, but is not so
+pronounced. The beautiful figure in "bird's eye maple"
+is supposed to be due to the boring action of insects in
+the early growth of the tree, causing pits or grooves, which
+in time become filled up by being overlain by fresh layers
+of wood growth; these peculiar and unique markings
+are found only in the older and inner portion of the tree.</p>
+
+<p>Pitch pine has sometimes a very beautiful "figure," but
+it generally does not go deep into the timber; walnut has
+quite a variety of "figures," and so has the elm. It is in
+mahogany, however, that we find the greatest variety of
+"figure," and as this timber is only used for furniture and
+fancy work, a good "figure" greatly enhances its value,
+as firmly figured logs bring fancy prices.</p>
+
+<p>Mahogany, unlike the oak, never draws its "figure" from
+its small and almost unnoticeable medullary rays, but
+from the twisted condition of its fibres; the natural growth
+of mahogany produces a straight wood; what is called
+"figured" is unnatural and exceptional, and thus adds
+to its value as an ornamental wood. These peculiarities
+are rarely found in the earlier portion of the tree that is
+near the center, being in this respect quite different from
+maple; they appear when the tree is more fully developed,
+and consist of bundles of woody fibres which, instead of
+being laid in straight lines, behave in an erratic manner
+and are deposited in a twisted form; sometimes it may
+be caused by the intersection of branches, or possibly by
+the crackling of the bark pressing on the wood, and thus<span class='pagenum'><a name="Page_97" id="Page_97">[97]</a></span>
+moving it out of its natural straight course, causing a
+wavy line which in time becomes accentuated.</p>
+
+<p>It will have been observed by most people that the outer
+portion of a tree is often indented by the bark, and the
+outer rings often follow a sinuous course which corresponds
+to this indention, but in most trees, after a few years, this
+is evened up and the annual rings assume their nearly
+circular form; it is supposed by some that in the case of
+mahogany this is not the case, and that the indentations
+are even accentuated.</p>
+
+<p>The best figured logs of timber are secured from trees
+which grow in firm rocky soil; those growing on low-lying
+or swampy ground are seldom figured. To the practical
+woodworker the figure in mahogany causes some difficulty
+in planing the wood to a smooth surface; some portions
+plane smooth, others are the "wrong way of the grain."</p>
+
+<p>Figure in wood is effected by the way light is thrown
+upon it, showing light if seen from one direction, and dark
+if viewed from another, as may easily be observed by holding
+a piece of figured mahogany under artificial light and
+looking at it from opposite directions. The characteristic
+markings on mahogany are "mottle," which is also
+found in sycamore, and is conspicuous on the backs of
+fiddles and violins, and is not in itself valuable; it runs
+the transverse way of the fibres and is probably the effect
+of the wind upon the tree in its early stages of growth.
+"Roe," which is said to be caused by the contortion of
+the woody fibres, and takes a wavy line parallel to them,
+is also found in the hollow of bent stems and in the root
+structure, and when combined with "mottle" is very
+valuable. "Dapple" is an exaggerated form of mottle.
+"Thunder shake," "wind shake," or "tornado shake" is
+a rupture of the fibres across the grain, which in mahogany
+does not always break them; the tree swaying in the wind
+only strains its fibres, and thus produces mottle in the wood.</p>
+
+
+
+<h3 style="padding-bottom: 0em"><a name="SECTION_V" id="SECTION_V"></a>SECTION V<span class='pagenum'><a name="Page_98" id="Page_98">[98]</a></span></h3>
+
+<h2 style="padding-bottom: 1em">ENEMIES OF WOOD</h2>
+
+
+<p><span class="smcap">From</span> the writer's personal investigations of this subject
+in different sections of the country, the damage to
+forest products of various kinds from this cause seems
+to be far more extensive than is generally recognized.
+Allowing a loss of five per cent on the total value of the
+forest products of the country, which the writer believes
+to be a conservative estimate, it would amount to something
+over $30,000,000 annually. This loss differs from
+that resulting from insect damage to natural forest resources,
+in that it represents more directly a loss of money
+invested in material and labor. In dealing with the insects
+mentioned, as with forest insects in general, the
+methods which yield the best results are those which relate
+directly to preventing attack, as well as those which are
+unattractive or unfavorable. The insects have two objects
+in their attack: one is to obtain food, the other is to prepare
+for the development of their broods. Different
+species of insects have special periods during the season
+of activity (March to November), when the adults are
+on the wing in search of suitable material in which to
+deposit their eggs. Some species, which fly in April, will
+be attracted to the trunks of recently felled pine trees or
+to piles of pine sawlogs from trees felled the previous
+winter. They are not attracted to any other kind of
+timber, because they can live only in the bark or wood
+of pine, and only in that which is in the proper condition
+to favor the hatching of their eggs and the normal development
+of their young. As they fly only in April,
+they cannot injure the logs of trees felled during the remainder
+of the year.<span class='pagenum'><a name="Page_99" id="Page_99">[99]</a></span></p>
+
+<p>There are also oak insects, which attack nothing but
+oak; hickory, cypress, and spruce insects, etc., which have
+different habits and different periods of flight, and require
+special conditions of the bark and wood for depositing
+their eggs or for subsequent development of their broods.
+Some of these insects have but one generation in a year,
+others have two or more, while some require more than
+one year for the complete development and transformation.
+Some species deposit their eggs in the bark or wood of
+trees soon after they are felled or before any perceptible
+change from the normal living tissue has taken place;
+other species are attracted only to dead bark and dead
+wood of trees which have been felled or girdled for several
+months; others are attracted to dry and seasoned wood;
+while another class will attack nothing but very old, dry
+bark or wood of special kinds and under special conditions.
+Thus it will be seen how important it is for the
+practical man to have knowledge of such of the foregoing
+facts as apply to his immediate interest in the manufacture
+or utilization of a given forest product, in order that he
+may with the least trouble and expense adjust his business
+methods to meet the requirements for preventing
+losses.</p>
+
+<p>The work of different kinds of insects, as represented
+by special injuries to forest products, is the first thing to
+attract attention, and the distinctive character of this
+work is easily observed, while the insect responsible for
+it is seldom seen, or it is so difficult to determine by the
+general observer from descriptions or illustrations that
+the species is rarely recognized. Fortunately, the character
+of the work is often sufficient in itself to identify the cause
+and suggest a remedy, and in this section primary consideration
+is given to this phase of the subject.</p>
+
+
+<h4>Ambrosia or Timber Beetles</h4>
+
+<div class="figcenter" style="width: 450px;"><p class="anchor"><a name="Fig_22" id="Fig_22"></a></p>
+<img src="images/fig22.jpg" width="450" height="283" alt="Work of Ambrosia Beetles in Tulip or Yellow Poplar Wood" title="Work of Ambrosia Beetles in Tulip or Yellow Poplar Wood" />
+
+<p class="caption">Fig. 22. Work of Ambrosia Beetles in Tulip or Yellow Poplar Wood.
+<i>a</i>, work of <i>Xyleborus affinis</i> and <i>Xyleborus inermis</i>; <i>b</i>, <i>Xyleborus obesus</i>
+and work; <i>c</i>, bark; <i>d</i>, sapwood; <i>e</i>, heartwood.</p>
+</div>
+
+<div class="figcenter" style="width: 450px; padding-top: 2em"><p class="anchor"><a name="Fig_23" id="Fig_23"></a></p>
+<img src="images/fig23.jpg" width="450" height="277" alt="Work of Ambrosia Beetles in Oak" title="Work of Ambrosia Beetles in Oak" />
+
+<p class="caption">Fig. 23. Work of Ambrosia Beetles in Oak. <i>a</i>, <i>Monarthrum mali</i> and work;
+<i>b</i>, <i>Platypus compositus</i> and work; <i>c</i>, bark; <i>d</i>, sapwood; <i>e</i>, heartwood;
+<i>f</i>, character of work in wood from injured log.</p>
+</div>
+
+<p>The characteristic work of this class of wood-boring
+beetles is shown in <a href="#Fig_22">Figs. 22</a> and <a href="#Fig_23">23</a>. The injury consists
+of pinhole and stained-wood defects in the sapwood and
+heartwood of recently felled or girdled trees, sawlogs,
+pulpwood, stave and shingle bolts, green or unseasoned<span class='pagenum'><a name="Page_100" id="Page_100">[100]</a></span>
+lumber, and staves and heads of barrels containing alcoholic
+liquids. The holes and galleries are made by the
+adult parent beetles, to serve as entrances and temporary
+houses or nurseries for the development of their broods
+of young, which feed on a fungus growing on the walls of
+the galleries.</p>
+
+<p>The growth of this ambrosia-like fungus is induced
+and controlled by the parent beetles, and the young are<span class='pagenum'><a name="Page_101" id="Page_101">[101]</a></span>
+dependent upon it for food. The wood must be in exactly
+the proper condition for the growth of the fungus
+in order to attract the beetles and induce them to excavate
+their galleries; it must have a certain degree of moisture
+and other favorable qualities, which usually prevail during
+the period involved in the change from living, or normal,
+to dead or dry wood; such a condition is found in recently
+felled trees, sawlogs, or like crude products.</p>
+
+<p>There are two general types or classes of these galleries:
+one in which the broods develop together in the main
+burrows (see <a href="#Fig_22">Fig. 22</a>), the other in which the individuals
+develop in short, separate side chambers, extending at
+right angles from the primary galleries (see <a href="#Fig_23">Fig. 23</a>). The
+galleries of the latter type are usually accompanied by a
+distinct staining of the wood, while those of the former
+are not.</p>
+
+<p>The beetles responsible for this work are cylindrical in
+form, apparently with a head (the prothorax) half as long
+as the remainder of the body (see <a href="#Fig_22">Figs. 22</a>, <i>a</i>, and <a href="#Fig_23">23</a>, <i>a</i>).</p>
+
+<p>North American species vary in size from less than
+one-tenth to slightly more than two-tenths of an inch,
+while some of the subtropical and tropical species attain
+a much larger size. The diameter of the holes made by
+each species corresponds closely to that of the body, and
+varies from about one-twentieth to one-sixteenth of an
+inch for the tropical species.</p>
+
+
+<h4>Round-headed Borers</h4>
+
+<div class="figcenter" style="width: 450px;"><p class="anchor"><a name="Fig_24" id="Fig_24"></a></p>
+<img src="images/fig24.jpg" width="450" height="287" alt="Work of Round-headed and Flat-headed Borers in Pine" title="Work of Round-headed and Flat-headed Borers in Pine" />
+
+<p class="caption">Fig. 24. Work of Round-headed and Flat-headed Borers in Pine. <i>a</i>, work
+of round-headed borer, "sawyer," <i>Monohammus spiculatus</i>, natural
+size <i>b</i>, <i>Ergates spiculatus</i>; <i>c</i>, work of flat-headed borer, <i>Buprestis</i>,
+larva and adult; <i>d</i>, bark; <i>e</i>, sapwood; <i>f</i>, heartwood.</p>
+</div>
+
+<p>The character of the work of this class of wood- and bark-boring
+grubs is shown in <a href="#Fig_24">Fig. 24</a>. The injuries consist
+of irregular flattened or nearly round wormhole defects
+in the wood, which sometimes result in the destruction<span class='pagenum'><a name="Page_102" id="Page_102">[102]</a></span>
+of valuable parts of the wood or bark material. The sapwood
+and heartwood of recently felled trees, sawlogs,
+poles posts, mine props, pulpwood and cordwood, also
+lumber or square timber, with bark on the edges, and
+construction timber in new and old buildings, are injured
+by wormhole defects, while the valuable parts of stored
+oak and hemlock tanbark and certain kinds of wood are
+converted into worm-dust. These injuries are caused
+by the young or larvae of long-horned beetles. Those
+which infest the wood hatch from eggs deposited in the
+outer bark of logs and like material, and the minute grubs
+hatching therefrom bore into the inner bark, through
+which they extend their irregular burrows, for the purpose
+of obtaining food from the sap and other nutritive material
+found in the plant tissue. They continue to extend and
+enlarge their burrows as they increase in size, until they
+are nearly or quite full grown. They then enter the wood
+and continue their excavations deep into the sapwood or
+heartwood until they attain their normal size. They
+then excavate pupa cells in which to transform into adults,<span class='pagenum'><a name="Page_103" id="Page_103">[103]</a></span>
+which emerge from the wood through exit holes in the
+surface. This class of borers is represented by a large
+number of species. The adults, however, are seldom seen
+by the general observer unless cut out of the wood before
+they have emerged.</p>
+
+
+<h4>Flat-headed Borers</h4>
+
+<p>The work of the flat-headed borers (<a href="#Fig_24">Fig. 24</a>) is only
+distinguished from that of the preceding by the broad,
+shallow burrows, and the much more oblong form of the
+exit holes. In general, the injuries are similiar, and effect
+the same class of products, but they are of much less importance.
+The adult forms are flattened, metallic-colored
+beetles, and represent many species, of various sizes.</p>
+
+
+<h4>Timber Worms</h4>
+
+<div class="figcenter" style="width: 450px;"><p class="anchor"><a name="Fig_25" id="Fig_25"></a></p>
+<img src="images/fig25.jpg" width="450" height="277" alt="Work of Timber Worms in Oak" title="Work of Timber Worms in Oak" />
+
+<p class="caption">Fig. 25. Work of Timber Worms in Oak. <i>a</i>, work of oak timber worm,
+<i>Eupsalis minuta</i>; <i>b</i>, barked surface; <i>c</i>, bark; <i>d</i>, sapwood timber worm,
+<i>Hylocoetus lugubris</i>, and work; <i>e</i>, sapwood.</p>
+</div>
+
+<p>The character of the work done by this class is shown
+in <a href="#Fig_25">Fig. 25</a>. The injury consists of pinhole defects in the
+sapwood and heartwood of felled trees, sawlogs and like
+material which have been left in the woods or in piles in the
+open for several months during the warmer seasons. Stave<span class='pagenum'><a name="Page_104" id="Page_104">[104]</a></span>
+and shingle bolts and closely piled oak lumber and square
+timbers also suffer from injury of this kind. These injuries
+are made by elongate, slender worms or larvae,
+which hatch from eggs deposited by the adult beetles in the
+outer bark, or, where there is no bark, just beneath the
+surface of the wood. At first the young larvae bore
+almost invisible holes for a long distance through the sapwood
+and heartwood, but as they increase in size the same
+holes are enlarged and extended until the larvae have attained
+their full growth. They then transform to adults,
+and emerge through the enlarged entrance burrows. The
+work of these timber worms is distinguished from that of
+the timber beetles by the greater variation in the size of
+holes in the same piece of wood, also by the fact that they
+are not branched from a single entrance or gallery, as are
+those made by the beetles.</p>
+
+<div class="figcenter" style="width: 450px;"><p class="anchor"><a name="Fig_26" id="Fig_26"></a></p>
+<img src="images/fig26.jpg" width="450" height="173" alt="Work of Powder Post Beetle" title="Work of Powder Post Beetle" />
+
+<p class="caption">Fig. 26. Work of Powder Post Beetle, <i>Sinoxylon basilare</i>, in Hickory Poles,
+showing Transverse Egg Galleries excavated by the Adult, <i>a</i>, entrance;
+<i>b</i>, gallery; <i>c</i>, adult.</p>
+</div>
+
+<div class="figcenter" style="width: 450px; padding-top: 2em"><p class="anchor"><a name="Fig_27" id="Fig_27"></a></p>
+<img src="images/fig27.jpg" width="450" height="125" alt="Work of Powder Post Beetle" title="Work of Powder Post Beetle" />
+
+<p class="caption">Fig. 27. Work of Powder Post Beetle, <i>Sinoxylon basilare</i>, in Hickory Pole.
+<i>a</i>, character of work by larvae; <i>b</i>, exit holes made by emerging broods.<span class='pagenum'><a name="Page_105" id="Page_105">[105]</a></span></p>
+</div>
+
+
+<h4>Powder Post Borers</h4>
+
+
+<div class="figright" style="width: 158px;"><p class="anchor"><a name="Fig_28" id="Fig_28"></a></p>
+<img src="images/fig28.jpg" width="158" height="400" alt="Work of Powder Post
+Beetles" title="Work of Powder Post
+Beetles" />
+</div>
+
+
+<p>The character of the work of this class of insects is
+shown in <a href="#Fig_26">Figs. 26</a>, <a href="#Fig_27">27</a>, and <a href="#Fig_28">28</a>. The injury consists of
+closely placed burrows, packed
+with borings, or a completely
+destroyed or powdered condition
+of the wood of seasoned products,
+such as lumber, crude and
+finished handle and wagon stock,
+cooperage and wooden truss
+hoops, furniture, and inside finish
+woodwork, in old buildings, as
+well as in many other crude or
+finished and utilized woods.
+This is the work of both the
+adults and young stages of some
+species, or of the larval stage
+alone of others. In the former,
+the adult beetles deposit their
+eggs in burrows or galleries excavated
+for the purpose, as in
+<a href="#Fig_26">Figs. 26</a> and <a href="#Fig_27">27</a>, while in the
+latter (<a href="#Fig_28">Fig. 28</a>) the eggs are on
+or beneath the surface of the
+wood. The grubs complete the
+destruction by boring through
+the solid wood in all directions
+and packing their burrows with
+the powdered wood. When they
+are full grown they transform to
+the adult, and emerge from the
+injured material through holes in
+the surface. Some of the species
+continue to work in the same
+wood until many generations
+have developed and emerged or
+until every particle of wood
+tissue has been destroyed and the available nutritive substance
+extracted.</p>
+
+<p class="caption" style="padding-top: 2em; padding-left: 4em">Fig. 28. Work of Powder Post
+Beetles, <i>Lyctus striatus</i>, in
+Hickory Handles and Spokes.
+<i>a</i>, larva; <i>b</i>, pupa; <i>c</i>, adult;
+<i>d</i>, exit holes; <i>e</i>, entrance of
+larvae (vents for borings are
+exits of parasites); <i>f</i>, work
+of larvae; <i>g</i>, wood, completely
+destroyed; <i>h</i>, sapwood;
+<i>i</i>, heartwood.<span class='pagenum'><a name="Page_106" id="Page_106">[106]</a></span></p>
+
+<h4>Conditions Favorable for Insect Injury&mdash;Crude Products&mdash;Round
+Timber with Bark on</h4>
+
+<p>Newly felled trees, sawlogs, stave and heading bolts,
+telegraph poles, posts, and the like material, cut in the
+fall and winter, and left on the ground or in close piles
+during a few weeks or months in the spring or summer,
+causing them to heat and sweat, are especially liable to
+injury by ambrosia beetles (<a href="#Fig_22">Figs. 22</a> and <a href="#Fig_23">23</a>), round and
+flat-headed borers (<a href="#Fig_24">Fig. 24</a>), and timber worms (<a href="#Fig_25">Fig. 25</a>),
+as are also trees felled in the warm season, and left for a
+time before working up into lumber.</p>
+
+<p>The proper degree of moisture found in freshly cut
+living or dying wood, and the period when the insects are
+flying, are the conditions most favorable for attack. This
+period of danger varies with the time of the year the timber
+is felled and with the different kinds of trees. Those
+felled in late fall and winter will generally remain attractive
+to ambrosia beetles, and to the adults of round- and
+flat-headed borers during March, April, and May.
+Those felled in April to September may be attacked in
+a few days after they are felled, and the period of danger
+may not extend over more than a few weeks. Certain
+kinds of trees felled during certain months and seasons
+are never attacked, because the danger period prevails
+only when the insects are flying; on the other hand, if
+the same kinds of trees are felled at a different time, the
+conditions may be most attractive when the insects are
+active, and they will be thickly infested and ruined.</p>
+
+<p>The presence of bark is absolutely necessary for infestation
+by most of the wood-boring grubs, since the eggs
+and young stages must occupy the outer and inner portions
+before they can enter the wood. Some ambrosia
+and timber worms will, however, attack barked logs,
+especially those in close piles, and others shaded and
+protected from rapid drying.</p>
+
+<p>The sapwood of pine, spruce, fir, cedar, cypress, and
+the like softwoods is especially liable to injury by ambrosia
+beetles, while the heartwood is sometimes ruined by a
+class of round-headed borers, known as "sawyers." Yellow<span class='pagenum'><a name="Page_107" id="Page_107">[107]</a></span>
+poplar, oak, chestnut, gum, hickory, and most other
+hardwoods are as a rule attacked by species of ambrosia
+beetles, sawyers, and timber worms, different from those
+infesting the pines, there being but very few species which
+attack both.</p>
+
+<p>Mahogany and other rare and valuable woods imported
+from the tropics to this country in the form of round logs,
+with or without bark on, are commonly damaged more
+or less seriously by ambrosia beetles and timber worms.</p>
+
+<p>It would appear from the writer's investigations of
+logs received at the mills in this country, that the principal
+damage is done during a limited period&mdash;from the
+time the trees are felled until they are placed in fresh or
+salt water for transportation to the shipping points. If,
+however, the logs are loaded on a vessel direct from the
+shore, or if not left in the water long enough to kill the
+insects, the latter will continue their destructive work
+during transportation to other countries and after they
+arrive, and until cold weather ensues or the logs are converted
+into lumber.</p>
+
+<p>It was also found that a thorough soaking in sea-water,
+while it usually killed the insects at the time, did not prevent
+subsequent attacks by both foreign and native ambrosia
+beetles; also, that the removal of the bark from such
+logs previous to immersion did not render them entirely
+immune. Those with the bark off were attacked more
+than those with it on, owing to a greater amount of saline
+moisture retained by the bark.</p>
+
+
+<h4>How to Prevent Injury</h4>
+
+<p>From the foregoing it will be seen that some requisites
+for preventing these insect injuries to round timber are:</p>
+
+<div class="blockquot"><p>1. To provide for as little delay as possible between
+the felling of the tree and its manufacture into
+rough products. This is especially necessary with
+trees felled from April to September, in the region
+north of the Gulf States, and from March to November
+in the latter, while the late fall and winter
+cutting should all be worked up by March or April.<span class='pagenum'><a name="Page_108" id="Page_108">[108]</a></span></p>
+
+<p>2. If the round timber must be left in the woods or on
+the skidways during the danger period, every precaution
+should be taken to facilitate rapid drying
+of the inner bark, by keeping the logs off the ground
+in the sun, or in loose piles; or else the opposite
+extreme should be adopted and the logs kept in
+water.</p>
+
+<p>3. The immediate removal of all the bark from poles,
+posts, and other material which will not be seriously
+damaged by checking or season checks.</p>
+
+<p>4. To determine and utilize the proper months or seasons
+to girdle or fell different kinds of trees: Bald
+cypress in the swamps of the South are "girdled"
+in order that they may die, and in a few weeks or
+months dry out and become light enough to float.
+This method has been extensively adopted in sections
+where it is the only practicable one by which
+the timber can be transported to the sawmills.
+It is found, however, that some of these "girdled"
+trees are especially attractive to several species of
+ambrosia beetles (<a href="#Fig_22">Figs. 22</a> and <a href="#Fig_23">23</a>), round-headed
+borers (<a href="#Fig_24">Fig. 24</a>) and timber worms (<a href="#Fig_25">Fig. 25</a>), which
+cause serious injury to the sapwood or heartwood,
+while other trees "girdled" at a different time or
+season are not injured. This suggested to the
+writer the importance of experiments to determine
+the proper time to "girdle" trees to avoid losses, and
+they are now being conducted on an extensive
+scale by the United States Forest Service, in co-operation
+with prominent cypress operators in
+different sections of the cypress-growing region.</p></div>
+
+
+<h4>Saplings</h4>
+
+<p>Saplings, including hickory and other round hoop-poles
+and similiar products, are subject to serious injuries and
+destruction by round- and flat-headed borers (<a href="#Fig_24">Fig. 24</a>),
+and certain species of powder post borers (<a href="#Fig_26">Figs. 26</a> and <a href="#Fig_27">27</a>)
+before the bark and wood are dead or dry, and also by
+other powder post borers (<a href="#Fig_28">Fig. 28</a>) after they are dried and<span class='pagenum'><a name="Page_109" id="Page_109">[109]</a></span>
+seasoned. The conditions favoring attack by the former
+class are those resulting from leaving the poles in piles
+or bundles in or near the forest for a few weeks during the
+season of insect activity, and by the latter from leaving
+them stored in one place for several months.</p>
+
+
+<h4>Stave, Heading and Shingle Bolts</h4>
+
+<p>These are attacked by ambrosia beetles (<a href="#Fig_22">Figs. 22</a> and
+<a href="#Fig_23">23</a>), and the oak timber worm (<a href="#Fig_25">Fig. 25</a>, <i>a</i>), which, as has
+been frequently reported, cause serious losses. The conditions
+favoring attack by these insects are similiar to
+those mentioned under "Round Timber." The insects
+may enter the wood before the bolts are cut from the log
+or afterward, especially if the bolts are left in moist, shady
+places in the woods, in close piles during the danger period.
+If cut during the warm season, the bark should be removed
+and the bolts converted into the smallest practicable
+size and piled in such manner as to facilitate rapid
+drying.</p>
+
+
+<h4>Unseasoned Products in the Rough</h4>
+
+<p>Freshly sawn hardwood, placed in close piles during
+warm, damp weather in July and September, presents
+especially favorable conditions for injury by ambrosia
+beetles (<a href="#Fig_22">Figs. 22</a>, <i>a</i>, and <a href="#Fig_23">23</a>, <i>a</i>). This is due to the continued
+moist condition of such material.</p>
+
+<p>Heavy two-inch or three-inch stuff is also liable to attack
+even in loose piles with lumber or cross sticks. An
+example of the latter was found in a valuable lot of mahogany
+lumber of first grade, the value of which was
+reduced two thirds by injury from a native ambrosia
+beetle. Numerous complaints have been received from
+different sections of the country of this class of injury to
+oak, poplar, gum, and other hardwoods. In all cases it
+is the moist condition and retarded drying of the lumber
+which induces attack; therefore, any method which will
+provide for the rapid drying of the wood before or after
+piling will tend to prevent losses.</p>
+
+<p>It is important that heavy lumber should, as far as
+possible, be cut in the winter months and piled so that it<span class='pagenum'><a name="Page_110" id="Page_110">[110]</a></span>
+will be well dried out before the middle of March. Square
+timber, stave and heading bolts, with the bark on, often
+suffer from injuries by flat- or round-headed borers, hatching
+from eggs deposited in the bark of the logs before they
+are sawed and piled. One example of serious damage
+and loss was reported in which white pine staves for paint
+buckets and other small wooden vessels, which had been
+sawed from small logs, and the bark left on the edges,
+were attacked by a round-headed borer, the adults having
+deposited their eggs in the bark after the stock was sawn
+and piled. The character of the injury is shown in <a href="#Fig_29">Fig. 29</a>.
+Another example was reported from a manufacturer in
+the South, where the pieces of lumber which had strips
+of bark on one side were seriously damaged by the same
+kind of borer, the eggs having been deposited in the logs
+before sawing or in the bark after the lumber was piled.
+If the eggs are deposited in the logs, and the borers have
+entered the inner bark or the wood before sawing, they
+may continue their work regardless of methods of piling,
+but if such lumber is cut from new logs and placed in the
+pile while green, with the bark surface up, it will be much
+less liable to attack than if piled with the bark edges down.
+This liability of lumber with bark edges or sides to be
+attacked by insects suggests the importance of the removal
+of the bark, to prevent damage, or, if this is not
+practicable, the lumber with the bark on the sides should
+be piled in open, loose piles with the bark up, while that
+with the bark on the edges should be placed on the outer
+edges of the piles, exposed to the light and air.</p>
+
+<div class="figcenter" style="width: 256px;"><p class="anchor"><a name="Fig_29" id="Fig_29"></a></p>
+<img src="images/fig29.jpg" width="256" height="400" alt="Work of Round-headed Borers" title="Work of Round-headed Borers" />
+</div>
+
+<p class="caption" style="width: 50%; margin-left: auto; margin-right: auto">Fig. 29. Work of Round-headed Borers, <i>Callidium antennatum</i>, in White
+Pine Bucket Staves from New Hampshire. <i>a</i>, where egg was deposited
+in bark; <i>b</i>, larval mine; <i>c</i>, pupal cell; <i>d</i>, exit in bark; <i>e</i>, adult.</p>
+
+<p>In the Southern States it is difficult to keep green timber
+in the woods or in piles for any length of time, because of
+the rapidity which wood-destroying fungi attack it. This
+is particularly true during the summer season, when the
+humidity is greatest. There is really no easily-applied,
+general specific for these summer troubles in the handling
+of wood, but there are some suggestions that are worth
+while that it may be well to mention. One of these, and
+the most important, is to remove all the bark from the
+timber that has been cut, just as soon as possible after
+felling. And, in this, emphasis should be laid on the <small>ALL</small>,<span class='pagenum'><a name="Page_111" id="Page_111">[111]</a></span>
+as a piece of bark no larger than a man's little finger will
+furnish an entering place for insects, and once they get in,
+it is a difficult matter to get rid of them, for they seldom
+stop boring until they ruin the stick. And again, after
+the timber has been felled and the bark removed, it is
+well to get it to the mill pond or cut up into merchantable
+sizes and on to the pile as soon as possible. What is
+wanted is to get the timber up off the ground, to a
+place where it can get plenty of air, to enable the sap
+to dry up before it sours; and, besides, large units of
+wood are more likely to crack open on the ends from the<span class='pagenum'><a name="Page_112" id="Page_112">[112]</a></span>
+heat than they would if cut up into the smaller units
+for merchandizing.</p>
+
+<p>A moist condition of lumber and square timber, such
+as results from close or solid piles, with the bottom layers
+on the ground or on foundations of old decaying logs or
+near decaying stumps and logs, offers especially favorable
+conditions for the attack of white ants.</p>
+
+
+<h4>Seasoned Products in the Rough</h4>
+
+<p>Seasoned or dry timber in stacks or storage is liable to
+injury by powder post borers (<a href="#Fig_28">Fig. 28</a>). The conditions
+favoring attack are: (1) The presence of a large
+proportion of sapwood, as in hickory, ash, and similiar
+woods; (2) material which is two or more years old, or
+that which has been kept in one place for a long time;
+(3) access to old infested material. Therefore, such stock
+should be frequently examined for evidence of the presence
+of these insects. This is always indicated by fine, flour-like
+powder on or beneath the piles, or otherwise associated
+with such material. All infested material should be at
+once removed and the infested parts destroyed by burning.</p>
+
+
+<h4>Dry Cooperage Stock and Wooden Truss Hoops</h4>
+
+<p>These are especially liable to attack and serious injury
+by powder post borers (<a href="#Fig_28">Fig. 28</a>), under the same or similiar
+conditions as the preceding.</p>
+
+
+<h4>Staves and Heads of Barrels containing
+Alcoholic Liquids</h4>
+
+<p>These are liable to attack by ambrosia beetles (<a href="#Fig_22">Figs.
+22</a>, <i>a</i>, and <a href="#Fig_23">23</a>, <i>a</i>), which are attracted by the moist condition
+and possibly by the peculiar odor of the wood, resembling
+that of dying sapwood of trees and logs, which
+is their normal breeding place.</p>
+
+<p>There are many examples on record of serious losses
+of liquors from leakage caused by the beetles boring through
+the staves and heads of the barrels and casks in cellars
+and storerooms.</p>
+
+<p>The condition, in addition to the moisture of the wood,
+which is favorable for the presence of the beetles, is proximity<span class='pagenum'><a name="Page_113" id="Page_113">[113]</a></span>
+to their breeding places, such as the trunks and
+stumps of recently felled or dying oak, maple, and other
+hardwood or deciduous trees; lumber yards, sawmills,
+freshly-cut cordwood, from living or dead trees, and forests
+of hardwood timber. Under such conditions the beetles
+occur in great numbers, and if the storerooms and cellars
+in which the barrels are kept stored are damp, poorly ventilated,
+and readily accessible to them, serious injury is
+almost certain to follow.</p>
+
+
+
+<h3 style="padding-bottom: 0em"><a name="SECTION_VI" id="SECTION_VI"></a>SECTION VI<span class='pagenum'><a name="Page_114" id="Page_114">[114]</a></span></h3>
+
+<h2>WATER IN WOOD</h2>
+
+
+<h3 style="padding-top: 0em">DISTRIBUTION OF WATER IN WOOD</h3>
+
+
+<h4>Local Distribution of Water in Wood</h4>
+
+<p><span class="smcap">As</span> seasoning means essentially the more or less rapid
+evaporation of water from wood, it will be necessary to discuss at the very outset where water is found in wood,
+and its local seasonal distribution in a tree.</p>
+
+<p>Water may occur in wood in three conditions: (1) It
+forms the greater part (over 90 per cent) of the protoplasmic
+contents of the living cells; (2) it saturates the
+walls of all cells; and (3) it entirely or at least partly fills
+the cavities of the lifeless cells, fibres, and vessels.</p>
+
+<p>In the sapwood of pine it occurs in all three forms; in
+the heartwood only in the second form, it merely saturates
+the walls.</p>
+
+<p>Of 100 pounds of water associated with 100 pounds of
+dry wood substance taken from 200 pounds of fresh sapwood
+of white pine, about 35 pounds are needed to saturate
+the cell walls, less than 5 pounds are contained in the
+living cells, and the remaining 60 pounds partly fill the
+cavities of the wood fibres. This latter forms the sap
+as ordinarily understood.</p>
+
+<p>The wood next to the bark contains the most water.
+In the species which do not form heartwood, the decrease
+toward the pith is gradual, but where heartwood is formed
+the change from a more moist to a drier condition is usually
+quite abrupt at the sapwood limit.</p>
+
+<p>In long-leaf pine, the wood of the outer one inch of a
+disk may contain 50 per cent of water, that of the next,
+or the second inch, only 35 per cent, and that of the heartwood,<span class='pagenum'><a name="Page_115" id="Page_115">[115]</a></span>
+only 20 per cent. In such a tree the amount of
+water in any one section varies with the amount of sapwood,
+and is greater for the upper than the lower cuts,
+greater for the limbs than the stems, and greatest of all
+in the roots.</p>
+
+<p>Different trees, even of the same kind and from the
+same place, differ as to the amount of water they contain.
+A thrifty tree contains more water than a stunted one,
+and a young tree more than on old one, while the wood
+of all trees varies in its moisture relations with the season
+of the year.</p>
+
+
+<h4>Seasonal Distribution of Water in Wood</h4>
+
+<p>It is generally supposed that trees contain less water
+in winter than in summer. This is evidenced by the
+popular saying that "the sap is down in the winter." This
+is probably not always the case; some trees contain as
+much water in winter as in summer, if not more. Trees
+normally contain the greatest amount of water during
+that period when the roots are active and the leaves are
+not yet out. This activity commonly begins in January,
+February, and March, the exact time varying with the
+kind of timber and the local atmospheric conditions. And
+it has been found that green wood becomes lighter or
+contains less water in late spring or early summer, when
+transpiration through the foliage is most rapid. The
+amount of water at any one season, however, is doubtless
+much influenced by the amount of moisture in the soil.
+The fact that the bark peels easily in the spring depends
+on the presence of incomplete, soft tissue found between
+wood and bark during this season, and has little to do
+with the total amount of water contained in the wood of
+the stem.</p>
+
+<p>Even in the living tree a flow of sap from a cut occurs
+only in certain kinds of trees and under special circumstances.
+From boards, felled timber, etc., the water
+does not flow out, as is sometimes believed, but must be
+evaporated. The seeming exceptions to this rule are
+mostly referable to two causes; clefts or "shakes" will<span class='pagenum'><a name="Page_116" id="Page_116">[116]</a></span>
+allow water contained in them to flow out, and water is
+forced out of sound wood, if very sappy, whenever the
+wood is warmed, just as water flows from green wood when
+put in a stove.</p>
+
+
+<h4>Composition of Sap</h4>
+
+<p>The term "sap" is an ambiguous expression. The
+sap in the tree descends through the bark, and except
+in early spring is not present in the wood of the tree
+except in the medullary rays and living tissues in the
+"sapwood."</p>
+
+<p>What flows through the "sapwood" is chiefly water
+brought from the soil. It is not pure water, but contains
+many substances in solution, such as mineral salts, and
+in certain species&mdash;maple, birch, etc., it also contains
+at certain times a small percentage of sugar and other
+organic matter.</p>
+
+<p>The water rises from the roots through the sapwood to
+the leaves, where it is converted into true "sap" which
+descends through the bark and feeds the living tissues
+between the bark and the wood, which tissues make the
+annual growth of the trunk. The wood itself contains
+very little true sap and the heartwood none.</p>
+
+<p>The wood contains, however, mineral substances, organic
+acids, volatile oils and gums, as resin, cedar oil, etc.</p>
+
+<p>All the conifers&mdash;pines, cedars, junipers, cypresses,
+sequoias, yews, and spruces&mdash;contain resin. The sap
+of deciduous trees&mdash;those which shed their leaves at
+stated seasons&mdash;is lacking in this element, and its constituents
+vary greatly in the different species. But there
+is one element common to all trees, and for that matter
+to almost all plant growth, and that is albumen.</p>
+
+<p>Both resin and albumen, as they exist in the sap of
+woods, are soluble in water; and both harden with heat,
+much the same as the white of an egg, which is almost
+pure albumen.</p>
+
+<p>These organic substances are the dissolved reserve food,
+stored during the winter in the pith rays, etc., of the wood
+and bark; generally but a mere trace of them is to be
+found. From this it appears that the solids contained<span class='pagenum'><a name="Page_117" id="Page_117">[117]</a></span>
+in the sap, such as albumen, gum, sugar, etc., cannot
+exercise the influence on the strength of the wood which is
+so commonly claimed for them.</p>
+
+
+<h4>Effects of Moisture on Wood</h4>
+
+<p>The question of the effect of moisture upon the strength
+and stiffness of wood offers a wide scope for study, and
+authorities consulted differ in conclusions. Two authorities
+give the tensile strength in pounds per square inch
+for white oak as 10,000 and 19,500, respectively; for
+spruce, 8,000 to 19,500, and other species in similiar startling
+contrasts.</p>
+
+<p>Wood, we are told, is composed of organic products.
+The chief material is cellulose, and this in its natural state
+in the living plant or green wood contains from 25 to 35
+per cent of its weight in moisture. The moisture renders
+the cellulose substance pliable. What the physical action
+of the water is upon the molecular structure of organic
+material, to render it softer and more pliable, is largely
+a matter of conjecture.</p>
+
+<p>The strength of a timber depends not only upon its
+relative freedom from imperfections, such as knots, crookedness
+of grain, decay, wormholes or ring-shakes, but also
+upon its density; upon the rate at which it grew, and
+upon the arrangement of the various elements which
+compose it.</p>
+
+<p>The factors effecting the strength of wood are therefore
+of two classes: (1) Those inherent in the wood itself and
+which may cause differences to exist between two pieces
+from the same species of wood or even between the two
+ends of a piece, and (2) those which are foreign to the wood
+itself, such as moisture, oils, and heat.</p>
+
+<p>Though the effect of moisture is generally temporary,
+it is far more important than is generally realized. So
+great, indeed, is the effect of moisture that under some
+conditions it outweighs all the other causes which effect
+strength, with the exception, perhaps of decided imperfections
+in the wood itself.<span class='pagenum'><a name="Page_118" id="Page_118">[118]</a></span></p>
+
+
+<h4>The Fibre Saturation Point in Wood</h4>
+
+<p>Water exists in green wood in two forms: (1) As liquid
+water contained in the cavities of the cells or pores, and
+(2) as "imbibed" water intimately absorbed in the substance
+of which the wood is composed. The removal of
+the free water from the cells or pores will evidently have
+no effect upon the physical properties or shrinkage of the
+wood, but as soon as any of the "imbibed" moisture is
+removed from the cell walls, shrinkage begins to take place
+and other changes occur. The strength also begins to
+increase at this time.</p>
+
+<p>The point where the cell walls or wood substance becomes
+saturated is called the "fibre saturation point,"
+and is a very significant point in the drying of wood.</p>
+
+<p>It is easy to remove the free water from woods which
+will stand a high temperature, as it is only necessary to
+heat the wood slightly above the boiling point in a closed
+vessel, which will allow the escape of the steam as it is
+formed, but will not allow dry air to come in contact with
+the wood, so that the surface will not become dried below
+its saturation point. This can be accomplished with
+most of the softwoods, but not as a rule with the hardwoods,
+as they are injured by the temperature necessary.</p>
+
+<p>The chief difficulties are encountered in evaporating
+the "imbibed" moisture and also where the free water
+has to be removed through its gradual transfusion instead
+of boiling. As soon as the imbibed moisture begins to
+be extracted from any portion, shrinkage takes place and
+stresses are set up in the wood which tend to cause checking.</p>
+
+<p>The fibre saturation point lies between moisture conditions
+of 25 and 30 per cent of the dry weight of the
+wood, depending on the species. Certain species of eucalyptus,
+and probably other woods, however, appear to
+be exceptional in this respect, in that shrinkage begins
+to take place at a moisture condition of 80 to 90 per cent
+of the dry weight.</p>
+
+
+
+<h3 style="padding-bottom: 0em"><a name="SECTION_VII" id="SECTION_VII"></a>SECTION VII<span class='pagenum'><a name="Page_119" id="Page_119">[119]</a></span></h3>
+
+<h2 style="padding-bottom: 1em">WHAT SEASONING IS</h2>
+
+
+<p><span class="smcap">Seasoning</span> is ordinarily understood to mean drying.
+When exposed to the sun and air, the water in green wood
+rapidly evaporates. The rate of evaporation will depend
+on: (1) the kind of wood; (2) the shape and thickness of
+the timber; and (3) the conditions under which the wood
+is placed or piled.</p>
+
+<p>Pieces of wood completely surrounded by air, exposed
+to the wind and the sun, and protected by a roof from
+rain and snow, will dry out very rapidly, while wood piled
+or packed close together so as to exclude the air, or left
+in the shade and exposed to rain and snow, will dry out
+very slowly and will also be subject to mould and decay.</p>
+
+<p>But seasoning implies other changes besides the evaporation
+of water. Although we have as yet only a vague
+conception as to the exact nature of the difference between
+seasoned and unseasoned wood, it is very probable that
+one of these consists in changes in the albuminous substances
+in the wood fibres, and possibly also in the tannins,
+resins, and other incrusting substances. Whether the
+change in these substances is merely a drying-out, or
+whether it consists in a partial decomposition is at yet
+undetermined. That the change during the seasoning
+process is a profound one there can be no doubt, because
+experience has shown again and again that seasoned wood
+fibre is very much more permeable, both for liquids and
+gases than the living, unseasoned fibre.</p>
+
+<p>One can picture the albuminous substances as forming
+a coating which dries out and possibly disintegrates when
+the wood dries. The drying-out may result in considerable
+shrinkage, which may make the wood fibre more
+porous. It is also possible that there are oxidizing influences<span class='pagenum'><a name="Page_120" id="Page_120">[120]</a></span>
+at work within these substances which result in
+their disintegration. Whatever the exact nature of the
+change may be, one can say without hesitation that exposure
+to the wind and air brings about changes in the
+wood, which are of such a nature that the wood becomes
+drier and more permeable.</p>
+
+<p>When seasoned by exposure to live steam, similiar
+changes may take place; the water leaves the wood in the
+form of steam, while the organic compounds in the walls
+probably coagulate or disintegrate under the high temperature.</p>
+
+<p>The most effective seasoning is without doubt that
+obtained by the uniform, slow drying which takes place
+in properly constructed piles outdoors, under exposure
+to the winds and the sun and under cover from the rain
+and snow, and is what has been termed "air-seasoning."
+By air-seasoning oak and similiar hardwoods, nature performs
+certain functions that cannot be duplicated by any
+artificial means. Because of this, woods of this class
+cannot be successfully kiln-dried green from the saw.</p>
+
+<p>In drying wood, the free water within the cells passes
+through the cell walls until the cells are empty, while the
+cell walls remain saturated. When all the free water has
+been removed, the cell walls begin to yield up their moisture.
+Heat raises the absorptive power of the fibres and
+so aids the passage of water from the interior of the cells.
+A confusion in the word "sap" is to be found in many
+discussions of kiln-drying; in some instances it means
+water, in other cases it is applied to the organic substances
+held in a water solution in the cell cavities. The term is
+best confined to the organic substances from the living
+cell. These substances, for the most part of the nature
+of sugar, have a strong attraction for water and water
+vapor, and so retard drying and absorb moisture into
+dried wood. High temperatures, especially those produced
+by live steam, appear to destroy these organic compounds
+and therefore both to retard and to limit the
+reabsorption of moisture when the wood is subsequently
+exposed to the atmosphere.</p>
+
+<p>Air-dried wood, under ordinary atmospheric temperatures,<span class='pagenum'><a name="Page_121" id="Page_121">[121]</a></span>
+retains from 10 to 20 per cent of moisture, whereas
+kiln-dried wood may have no more than 5 per cent as it
+comes from the kiln. The exact figures for a given species
+depend in the first case upon the weather conditions, and
+in the second case upon the temperature in the kiln and
+the time during which the wood is exposed to it. When
+wood that has been kiln-dried is allowed to stand in the
+open, it apparently ceases to reabsorb moisture from the
+air before its moisture content equals that of wood which
+has merely been air-dried in the same place, and under
+the same conditions, in other words kiln-dried wood will
+not absorb as much moisture as air-dried wood under the
+same conditions.</p>
+
+
+<h4>Difference between Seasoned and Unseasoned Wood</h4>
+
+<p>Although it has been known for a long time that there
+is a marked difference in the length of life of seasoned and
+of unseasoned wood, the consumers of wood have shown
+very little interest in its seasoning, except for the purpose
+of doing away with the evils which result from checking,
+warping, and shrinking. For this purpose both kiln-drying
+and air-seasoning are largely in use.</p>
+
+<p>The drying of material is a subject which is extremely
+important to most industries, and in no industry is it of
+more importance than in the lumber trade. Timber
+drying means not only the extracting of so much water,
+but goes very deeply into the quality of the wood, its
+workability and its cell strength, etc.</p>
+
+<p>Kiln-drying, which dries the wood at a uniformly rapid
+rate by artificially heating it in inclosed rooms, has become
+a part of almost every woodworking industry, as
+without it the construction of the finished product would
+often be impossible. Nevertheless much unseasoned or
+imperfectly seasoned wood is used, as is evidenced by the
+frequent shrinkage and warping of the finished articles.
+This is explained to a certain extent by the fact that the
+manufacturer is often so hard pressed for his product that
+he is forced to send out an inferior article, which the consumer
+is willing to accept in that condition rather than<span class='pagenum'><a name="Page_122" id="Page_122">[122]</a></span>
+to wait several weeks or months for an article made up
+of thoroughly seasoned material, and also that dry kilns
+are at present constructed and operated largely without
+thoroughgoing system.</p>
+
+<p>Forms of kilns and mode of operation have commonly
+been copied by one woodworking plant after the example of
+some neighboring establishment. In this way it has been
+brought about that the present practices have many shortcomings.
+The most progressive operators, however, have
+experimented freely in the effort to secure special results
+desirable for their peculiar products. Despite the diversity
+of practice, it is possible to find among the larger and more
+enterprising operators a measure of agreement, as to both
+methods and results, and from this to outline the essentials
+of a correct theory. As a result, properly seasoned wood
+commands a high price, and in some cases cannot be obtained
+at all.</p>
+
+<p>Wood seasoned out of doors, which by many is supposed
+to be much superior to kiln-dried material, is becoming
+very scarce, as the demand for any kind of wood is so great
+that it is thought not to pay to hold it for the time necessary
+to season it properly. How long this state of affairs
+is going to last it is difficult to say, but it is believed that
+a reaction will come when the consumer learns that in
+the long run it does not pay to use poorly seasoned material.
+Such a condition has now arisen in connection with another
+phase of the seasoning of wood; it is a commonly accepted
+fact that dry wood will not decay nearly so fast as wet
+or green wood; nevertheless, the immense superiority of
+seasoned over unseasoned wood for all purposes where
+resistance to decay is necessary has not been sufficiently
+recognized. In the times when wood of all kinds was
+both plentiful and cheap, it mattered little in most cases
+how long it lasted or resisted decay. Wood used for
+furniture, flooring, car construction, cooperage, etc., usually
+got some chance to dry out before or after it was placed
+in use. The wood which was exposed to decaying influences
+was generally selected from those woods which,
+whatever their other qualities might be, would resist decay
+longest.<span class='pagenum'><a name="Page_123" id="Page_123">[123]</a></span></p>
+
+<p>To-day conditions have changed, so that wood can no
+longer be used to the same extent as in former years.
+Inferior woods with less lasting qualities have been pressed
+into service. Although haphazard methods of cutting
+and subsequent use are still much in vogue, there are
+many signs that both lumbermen and consumers are
+awakening to the fact that such carelessness and wasteful
+methods of handling wood will no longer do, and must
+give way to more exact and economical methods. The
+reason why many manufacturers and consumers of wood
+are still using the older methods is perhaps because of
+long custom, and because they have not yet learned that,
+though the saving to be obtained by the application of
+good methods has at all times been appreciable, now,
+when wood is more valuable, a much greater saving is
+possible. The increased cost of applying economical
+methods is really very slight, and is many times exceeded
+by the value of the increased service which can be secured
+through its use.</p>
+
+
+<h4>Manner of Evaporation of Water</h4>
+
+<p>The evaporation of water from wood takes place largely
+through the ends, <i>i.e.</i>, in the direction of the longitudinal
+axis of the wood fibres. The evaporation from the other
+surfaces takes place very slowly out of doors, and with
+greater rapidity in a dry kiln. The rate of evaporation
+differs both with the kind of timber and its shape; that is,
+thin material will dry more rapidly than heavier stock.
+Sapwood dries faster than heartwood, and pine more
+rapidly than oak or other hardwoods.</p>
+
+<p>Tests made show little difference in the rate of evaporation
+in sawn and hewn stock, the results, however, not
+being conclusive. Air-drying out of doors takes from
+two months to a year, the time depending on the kind of
+timber, its thickness, and the climatic conditions. After
+wood has reached an air-dry condition it absorbs water
+in small quantities after a rain or during damp weather,
+much of which is immediately lost again when a few warm,
+dry days follow. In this way wood exposed to the weather<span class='pagenum'><a name="Page_124" id="Page_124">[124]</a></span>
+will continue to absorb water and lose it for indefinite
+periods.</p>
+
+<p>When soaked in water, seasoned woods absorb water
+rapidly. This at first enters into the wood through the
+cell walls; when these are soaked, the water will fill the
+cell lumen, so that if constantly submerged the wood may
+become completely filled with water.</p>
+
+<p>The following figures show the gain in weight by absorption
+of several coniferous woods, air-dry at the start,
+expressed in per cent of the kiln-dry weight:</p>
+
+<p class="center"><span class="smcap">Absorption of Water by Dry Wood</span></p>
+
+<table summary="absorption of water" cellpadding="2" class="kilnwood">
+<tr><td>&nbsp;</td><td style="padding: 0.5em; border: solid black 1px">White Pine</td><td style="padding: 0.5em; border: solid black 1px">Red Cedar</td><td style="padding: 0.5em; border: solid black 1px">Hemlock</td><td style="padding: 0.5em; border-bottom: solid black 1px">Tamarack</td></tr>
+<tr><td class="tableentry2" style="border-top: solid black 1px">Air-dried</td><td class="centered2">108</td><td class="centered2">109</td><td class="centered2">111</td><td class="centered2">108</td></tr>
+<tr><td class="tableentry2">Kiln-dried</td><td class="centered2">100</td><td class="centered2">100</td><td class="centered2">100</td><td class="centered2">100</td></tr>
+<tr><td class="tableentry2">In water 1 day</td><td class="centered2">135</td><td class="centered2">120</td><td class="centered2">133</td><td class="centered2">129</td></tr>
+<tr><td class="tableentry2">In water 2 days</td><td class="centered2">147</td><td class="centered2">126</td><td class="centered2">144</td><td class="centered2">136</td></tr>
+<tr><td class="tableentry2">In water 3 days</td><td class="centered2">154</td><td class="centered2">132</td><td class="centered2">149</td><td class="centered2">142</td></tr>
+<tr><td class="tableentry2">In water 4 days</td><td class="centered2">162</td><td class="centered2">137</td><td class="centered2">154</td><td class="centered2">147</td></tr>
+<tr><td class="tableentry2">In water 5 days</td><td class="centered2">165</td><td class="centered2">140</td><td class="centered2">158</td><td class="centered2">150</td></tr>
+<tr><td class="tableentry2">In water 7 days</td><td class="centered2">176</td><td class="centered2">143</td><td class="centered2">164</td><td class="centered2">156</td></tr>
+<tr><td class="tableentry2">In water 9 days</td><td class="centered2">179</td><td class="centered2">147</td><td class="centered2">168</td><td class="centered2">157</td></tr>
+<tr><td class="tableentry2">In water 11 days</td><td class="centered2">184</td><td class="centered2">149</td><td class="centered2">173</td><td class="centered2">159</td></tr>
+<tr><td class="tableentry2">In water 14 days</td><td class="centered2">187</td><td class="centered2">150</td><td class="centered2">176</td><td class="centered2">159</td></tr>
+<tr><td class="tableentry2">In water 17 days</td><td class="centered2">192</td><td class="centered2">152</td><td class="centered2">176</td><td class="centered2">161</td></tr>
+<tr><td class="tableentry2">In water 25 days</td><td class="centered2">198</td><td class="centered2">155</td><td class="centered2">180</td><td class="centered2">161</td></tr>
+<tr><td class="tableentry2" style="padding-bottom: 0.5em">In water 30 days</td><td class="centered2" style="padding-bottom: 0.5em">207</td><td class="centered2" style="padding-bottom: 0.5em">158</td><td class="centered2" style="padding-bottom: 0.5em">183</td><td class="centered2" style="padding-bottom: 0.5em">166</td></tr>
+</table>
+
+
+<h4>Rapidity of Evaporation</h4>
+
+<p>The rapidity with which water is evaporated, that is,
+the rate of drying, depends on the size and shape of the
+piece and on the structure of the wood. An inch board
+dries more than four times as fast as a four-inch plank, and
+more than twenty times as fast as a ten-inch timber.
+White pine dries faster than oak. A very moist piece of
+pine or oak will, during one hour, lose more than four times
+as much water per square inch from the cross-section, but
+only one half as much from the tangential as from the radial
+section. In a long timber, where the ends or cross-sections
+form but a small part of the drying surface, this difference<span class='pagenum'><a name="Page_125" id="Page_125">[125]</a></span>
+is not so evident. Nevertheless, the ends dry
+and shrink first, and being opposed in this shrinkage by
+the more moist adjoining parts, they check, the cracks
+largely disappearing as seasoning progresses.</p>
+
+<p>High temperatures are very effective in evaporating
+the water from wood, no matter how humid the air, and
+a fresh piece of sapwood may lose weight in boiling water,
+and can be dried to quite an extent in hot steam.</p>
+
+<p>In drying chemicals or fabrics, all that is required is to
+provide heat enough to vaporize the moisture and circulation
+enough to carry off the vapor thus secured, and the
+quickest and most economical means to these ends may
+be used. While on the other hand, in drying wood, whether
+in the form of standard stock or the finished product, the
+application of the requisite heat and circulation must be
+carefully regulated throughout the entire process, or
+warping and checking are almost certain to result. Moreover,
+wood of different shapes and thicknesses is very differently
+effected by the same treatment. Finally, the
+tissues composing the wood, which vary in form and physical
+properties, and which cross each other in regular directions,
+exert their own peculiar influences upon its behavior
+during drying. With our native woods, for instance,
+summer-wood and spring-wood show distinct tendencies
+in drying, and the same is true in a less degree of heartwood,
+as contrasted with sapwood. Or, again, pronounced
+medullary rays further complicate the drying problem.</p>
+
+
+<h4>Physical Properties that influence Drying</h4>
+
+<p>The principal properties which render the drying of
+wood peculiarly difficult are: (1) The irregular shrinkage;
+(2) the different ways in which water is contained; (3) the
+manner in which moisture transfuses through the wood
+from the center to the surface; (4) the plasticity of the
+wood substance while moist and hot; (5) the changes
+which take place in the hygroscopic and chemical nature
+of the surface; and (6) the difference produced in the total
+shrinkage by different rates of drying.</p>
+
+<p>The shrinkage is unequal in different directions and
+in different portions of the same piece. It is greatest in<span class='pagenum'><a name="Page_126" id="Page_126">[126]</a></span>
+the circumferential direction of the tree, being generally
+twice as great in this direction as in the radial direction.
+In the longitudinal direction, for most woods, it is almost
+negligible, being from 20 to over 100 times as great circumferentially
+as longitudinally.</p>
+
+<p>There is a great variation in different species in this
+respect. Consequently, it follows from necessity that
+large internal strains are set up when the wood shrinks,
+and were it not for its plasticity it would rupture. There
+is an enormous difference in the total amount of shrinkage
+of different species of wood, varying from a shrinkage of
+only 7 per cent in volume, based on the green dimensions,
+in the case of some of the cedars to nearly 50 per cent in
+the case of some species of eucalyptus.</p>
+
+<p>When the free water in the capillary spaces of the wood
+fibre is evaporated it follows the laws of evaporation from
+capillary spaces, except that the passages are not all free
+passages, and much of the water has to pass out by a
+process of transfusion through the moist cell walls. These
+cell walls in the green wood completely surround the cell
+cavities so that there are no openings large enough to offer
+a passage to water or air.</p>
+
+<p>The well-known "pits" in the cell walls extend through
+the secondary thickening only, and not through the primary
+walls. This statement applies to the tracheids and
+parenchyma cells in the conifer (gymnosperms), and to the
+tracheids, parenchyma cells, and the wood fibres in the
+broad-leaved trees (angiosperms); the vessels in the latter,
+however, form open passages except when clogged by
+ingrowth called tyloses, and the resin canals in the former
+sometimes form occasional openings.</p>
+
+<p>By heating the wood above the boiling point, corresponding
+to the external pressure, the free water passes through
+the cell walls more readily.</p>
+
+<p>To remove the moisture from the wood substance requires
+heat in addition to the latent heat of evaporation,
+because the molecules of moisture are so intimately associated
+with the molecules, minute particles composing
+the wood, that energy is required to separate them therefrom.<span class='pagenum'><a name="Page_127" id="Page_127">[127]</a></span></p>
+
+<p>Carefully conducted experiments show this to be from
+16.6 to 19.6 calories per grain of dry wood in the case of
+beech, long-leaf pine, and sugar maple.</p>
+
+<p>The difficulty imposed in drying, however, is not so
+much the additional heat required as it is in the rate at
+which the water transfuses through the solid wood.</p>
+
+
+
+<h3 style="padding-bottom: 0em"><a name="SECTION_VIII" id="SECTION_VIII"></a>SECTION VIII<span class='pagenum'><a name="Page_128" id="Page_128">[128]</a></span></h3>
+
+<h2 style="padding-bottom: 1em">ADVANTAGES IN SEASONING</h2>
+
+
+<p><span class="smcap">Three</span> most important advantages of seasoning have
+already been made apparent:</p>
+
+<div class="blockquot"><p>1. Seasoned timber lasts much longer than unseasoned.
+Since the decay of timber is due to the attacks of
+wood-destroying fungi, and since the most important
+condition of the growth of these fungi is water,
+anything which lessens the amount of water in
+wood aids in its preservation.</p>
+
+<p>2. In the case of treated timber, seasoning before treatment
+greatly increases the effectiveness of the
+ordinary methods of treatment, and seasoning after
+treatment prevents the rapid leaching out of the
+salts introduced to preserve the timber.</p>
+
+<p>3. The saving in freight where timber is shipped from
+one place to another. Few persons realize how
+much water green wood contains, or how much it
+will lose in a comparatively short time. Experiments
+along this line with lodge-pole pine, white
+oak, and chestnut gave results which were a surprise
+to the companies owning the timber.</p></div>
+
+<p>Freight charges vary considerably in different parts of
+the country; but a decrease of 35 to 40 per cent in weight
+is important enough to deserve everywhere serious consideration
+from those in charge of timber operations.</p>
+
+<p>When timber is shipped long distances over several
+roads, as is coming to be more and more the case, the saving
+in freight will make a material difference in the cost
+of lumber operations, irrespective of any other advantages
+of seasoning.<span class='pagenum'><a name="Page_129" id="Page_129">[129]</a></span></p>
+
+
+<h4>Prevention of Checking and Splitting</h4>
+
+<p>Under present methods much timber is rendered unfit
+for use by improper seasoning. Green timber, particularly
+when cut during January, February, and March,
+when the roots are most active, contains a large amount
+of water. When exposed to the sun and wind or to high
+temperatures in a drying room, the water will evaporate
+more rapidly from the outer than from the inner parts
+of the piece, and more rapidly from the ends than from
+the sides. As the water evaporates, the wood shrinks,
+and when the shrinkage is not fairly uniform the wood
+cracks and splits.</p>
+
+<p>When wet wood is piled in the sun, evaporation goes
+on with such unevenness that the timbers split and crack
+in some cases so badly as to become useless for the purpose
+for which it was intended. Such uneven drying can be
+prevented by careful piling, keeping the logs immersed
+in a log pond until wanted, or by piling or storing under
+an open shed so that the sun cannot get at them.</p>
+
+<p>Experiments have also demonstrated that injury to
+stock in the way of checking and splitting always develops
+immediately after the stock is taken into the dry
+kiln, and is due to the degree of humidity being too low.</p>
+
+<p>The receiving end of the kiln should always be kept
+moist, where the stock has not been steamed before being
+put into the kiln, as when the air is too dry it tends to
+dry the outside of the stock first&mdash;which is termed "case-hardening"&mdash;and
+in so doing shrinks and closes up the
+pores. As the material is moved down the kiln (as
+in the case of "progressive kilns"), it absorbs a
+continually increasing amount of heat, which tends
+to drive off the moisture still present in the center of
+the piece, the pores on the outside having been closed
+up, there is no exit for the vapor or steam that is being
+rapidly formed in the center of the piece. It must find
+its way out in some manner, and in doing so sets up strains,
+which result either in checking or splitting. If the humidity
+had been kept higher, the outside of the piece would
+not have dried so quickly, and the pores would have remained<span class='pagenum'><a name="Page_130" id="Page_130">[130]</a></span>
+open for the exit of the moisture from the interior
+of the piece, and this trouble would have been
+avoided. (See also article following.)</p>
+
+
+<h4>Shrinkage of Wood</h4>
+
+<p>Since in all our woods, cells with thick walls and cells
+with thin walls are more or less intermixed, and especially
+as the spring-wood and summer-wood nearly always differ
+from each other in this respect, strains and tendencies
+to warp are always active when wood dries out, because
+the summer-wood shrinks more than the spring-wood,
+and heavier wood in general shrinks more than light wood
+of the same kind.</p>
+
+<p>If a thin piece of wood after drying is placed upon a
+moist surface, the cells on the under side of the piece take
+up moisture and swell before the upper cells receive any
+moisture. This causes the under side of the piece to become
+longer than the upper side, and as a consequence
+warping occurs. Soon, however, the moisture penetrates
+to all the cells and the piece straightens out. But while
+a thin board of pine curves laterally it remains quite
+straight lengthwise, since in this direction both shrinkage
+and swelling are small. If one side of a green board is
+exposed to the sun, warping is produced by the removal of
+water and consequent shrinkage of the side exposed; this
+may be eliminated by the frequent turning of the topmost
+pieces of the piles in order that they may be dried evenly.</p>
+
+<p>As already stated, wood loses water faster from the
+ends than from the longitudinal faces. Hence the ends
+shrink at a different rate from the interior parts. The
+faster the drying at the surface, the greater is the difference
+in the moisture of the different parts, and hence the greater
+the strains and consequently also the greater amount of
+checking. This becomes very evident when freshly cut
+wood is placed in the sun, and still more when put into a
+hot, dry kiln. While most of these smaller checks are only
+temporary, closing up again, some large radial checks remain
+and even grow larger as drying progresses. Their
+cause is a different one and will presently be explained.
+The temporary checks not only appear at the ends, but<span class='pagenum'><a name="Page_131" id="Page_131">[131]</a></span>
+are developed on the sides also, only to a much smaller
+degree. They become especially annoying on the surface
+of thick planks of hardwoods, and also on peeled logs
+when exposed to the sun.</p>
+
+<p>So far we have considered the wood as if made up only
+of parallel fibres all placed longitudinally in the log.
+This, however, is not the case. A large part of the wood
+is formed by the medullary or pith rays. In pine over
+15,000 of these occur on a square inch of a tangential
+section, and even in oak the very large rays, which are
+readily visible to the eye, represent scarcely a hundredth
+part of the number which a microscope reveals, as the
+cells of these rays have their length at right angles to the
+direction of the wood fibres.</p>
+
+<p>If a large pith ray of white oak is whittled out and allowed
+to dry, it is found to shrink greatly in its width,
+while, as we have stated, the fibres to which the ray is
+firmly grown in the wood do not shrink in the same direction.
+Therefore, in the wood, as the cells of the pith ray
+dry they pull on the longitudinal fibres and try to shorten
+them, and, being opposed by the rigidity of the fibres, the
+pith ray is greatly strained. But this is not the only
+strain it has to bear. Since the fibres shrink as much
+again as the pith ray, in this its longitudinal direction,
+the fibres tend to shorten the ray, and the latter in opposing
+this prevents the former from shrinking as much
+as they otherwise would.</p>
+
+<p>Thus the structure is subjected to two severe strains
+at right angles to each other, and herein lies the greatest
+difficulty of wood seasoning, for whenever the wood dries
+rapidly these fibres have not the chance to "give" or accommodate
+themselves, and hence fibres and pith rays
+separate and checking results, which, whether visible or
+not, are detrimental in the use of the wood.</p>
+
+<p>The contraction of the pith rays parallel to the length
+of the board is probably one of the causes of the small
+amount of longitudinal shrinkage which has been observed
+in boards. This smaller shrinkage of the pith
+rays along the radius of the log (the length of the pith ray),
+opposing the shrinkage of the fibres in this direction, becomes<span class='pagenum'><a name="Page_132" id="Page_132">[132]</a></span>
+one of the causes of the second great trouble in
+wood seasoning, namely, the difference in the shrinkage
+along the radius and that along the rings or tangent. This
+greater tangential shrinkage appears to be due in part to
+the causes just mentioned, but also to the fact that the
+greatly shrinking bands of summer-wood are interrupted
+along the radius by as many bands of porous spring-wood,
+while they are continuous in the tangential direction. In
+this direction, therefore, each such band tends to shrink,
+as if the entire piece were composed of summer-wood,
+and since the summer-wood represents the greater part
+of the wood substance, this greater tendency to tangential
+shrinkage prevails.</p>
+
+<p>The effect of this greater tangential shrinkage effects
+every phase of woodworking. It leads to permanent
+checks and causes the log or piece to split open on drying.
+Sawed in two, the flat sides of the log become convex;
+sawed into timber, it checks along the median line of
+the four faces, and if converted into boards, the latter
+checks considerably from the end through the center, all
+owing to the greater tangential shrinkage of the wood.</p>
+
+<p>Briefly, then, shrinkage of wood is due to the fact that
+the cell walls grow thinner on drying. The thicker cell
+walls and therefore the heavier wood shrinks most, while
+the water in the cell cavities does not influence the volume
+of the wood.</p>
+
+<p>Owing to the great difference of cells in shape, size, and
+thickness of walls, and still more in their arrangement,
+shrinkage is not uniform in any kind of wood. This
+irregularity produces strains, which grow with the difference
+between adjoining cells and are greatest at the
+pith rays. These strains cause warping and checking,
+but exist even where no outward signs are visible. They
+are greater if the wood is dried rapidly than if dried slowly,
+but can never be entirely avoided.</p>
+
+<p>Temporary checks are caused by the more rapid drying
+of the outer parts of any stick; permanent checks
+are due to the greater shrinkage, tangentially, along the
+rings than along the radius. This, too, is the cause of
+most of the ordinary phenomena of shrinkage, such as<span class='pagenum'><a name="Page_133" id="Page_133">[133]</a></span>
+the difference in behavior of the entire and quartered logs,
+"bastard" (tangent) and rift (radial) boards, etc., and
+explains many of the phenomena erroneously attributed
+to the influence of bark, or of the greater shrinkage of
+outer and inner parts of any log.</p>
+
+<p>Once dry, wood may be swelled again to its original
+size by soaking in water, boiling, or steaming. Soaked
+pieces on drying shrink again as before; boiled and steamed
+pieces do the same, but to a slightly less degree. Neither
+hygroscopicity, <i>i.e.</i>, the capacity of taking up water, nor
+shrinkage of wood can be overcome by drying at temperatures
+below 200 degrees Fahrenheit. Higher temperatures,
+however, reduce these qualities, but nothing short of a
+coaling heat robs wood of the capacity to shrink and swell.</p>
+
+<p>Rapidly dried in a kiln, the wood of oak and other
+hardwoods "case-harden," that is, the outer part dries
+and shrinks before the interior has a chance to do the same,
+and thus forms a firm shell or case of shrunken, commonly
+checked wood around the interior. This shell does not
+prevent the interior from drying, but when this drying
+occurs the interior is commonly checked along the medullary
+rays, commonly called "honeycombing" or "hollow-horning."
+In practice this occurrence can be prevented
+by steaming or sweating the wood in the kiln, and still
+better by drying the wood in the open air or in a shed
+before placing in the kiln. Since only the first shrinkage
+is apt to check the wood, any kind of lumber which has
+once been air-dried (three to six months for one-inch stuff)
+may be subjected to kiln heat without any danger from
+this source.</p>
+
+<p>Kept in a bent or warped condition during the first
+shrinkage, the wood retains the shape to which it has
+been bent and firmly opposes any attempt at subsequent
+straightening.</p>
+
+<p>Sapwood, as a rule, shrinks more than heartwood of
+the same weight, but very heavy heartwood may shrink
+more than lighter sapwood. The amount of water in
+wood is no criterion of its shrinkage, since in wet wood
+most of the water is held in the cavities, where it has no
+effect on the volume.<span class='pagenum'><a name="Page_134" id="Page_134">[134]</a></span></p>
+
+<p>The wood of pine, spruce, cypress, etc., with its very
+regular structure, dries and shrinks evenly, and suffers
+much less in seasoning than the wood of broad-leaved
+(hardwood) trees. Among the latter, oak is the most
+difficult to dry without injury.</p>
+
+<p>Desiccating the air with certain chemicals will cause the
+wood to dry, but wood thus dried at 80 degrees Fahrenheit
+will still lose water in the kiln. Wood dried at 120 degrees
+Fahrenheit loses water still if dried at 200 degrees Fahrenheit,
+and this again will lose more water if the temperature
+be raised, so that <i>absolutely dry wood</i> cannot be obtained,
+and chemical destruction sets in before all the water is
+driven off.</p>
+
+<p>On removal from the kiln, the dry wood at once takes
+up moisture from the air, even in the driest weather. At
+first the absorption is quite rapid; at the end of a week
+a short piece of pine, 1<span class="above">1</span>&#8260;<span class="below">2</span> inches thick, has regained two
+thirds of, and, in a few months, all the moisture which it
+had when air-dry, 8 to 10 per cent, and also its former
+dimensions. In thin boards all parts soon attain the
+same degree of dryness. In heavy timbers the interior remains
+more moist for many months, and even years, than
+the exterior parts. Finally an equilibrium is reached,
+and then only the outer parts change with the weather.</p>
+
+<p>With kiln-dried woods all parts are equally dry, and
+when exposed, the moisture coming from the air must
+pass through the outer parts, and thus the order is reversed.
+Ordinary timber requires months before it is
+at its best. Kiln-dried timber, if properly handled, is
+prime at once.</p>
+
+<p>Dry wood if soaked in water soon regains its original
+volume, and in the heartwood portion it may even surpass
+it; that is to say, swell to a larger dimension than
+it had when green. With the soaking it continues to
+increase in weight, the cell cavities filling with water, and
+if left many months all pieces sink. Yet after a year's
+immersion a piece of oak 2 by 2 inches and only 6 inches
+long still contains air; <i>i.e.</i>, it has not taken up all the
+water it can. By rafting or prolonged immersion, wood
+loses some of its weight, soluble materials being leached<span class='pagenum'><a name="Page_135" id="Page_135">[135]</a></span>
+out, but it is not impaired either as fuel or as building
+material. Immersion, and still more boiling and steaming,
+reduce the hygroscopicity of wood and therefore also
+the troublesome "working," or shrinking and swelling.</p>
+
+<p>Exposure in dry air to a temperature of 300 degrees Fahrenheit
+for a short time reduces but does not destroy the
+hygroscopicity, and with it the tendency to shrink and
+swell. A piece of red oak which has been subjected to a
+temperature of over 300 degrees Fahrenheit still swells in
+hot water and shrinks in a dry kiln.</p>
+
+
+<h4>Expansion of Wood</h4>
+
+<p>It must not be forgotten that timber, in common with
+every other material, expands as well as contracts. If
+we extract the moisture from a piece of wood and so cause
+it to shrink, it may be swelled to its original volume by
+soaking it in water, but owing to the protection given to
+most timber in dwelling-houses it is not much affected by
+wet or damp weather. The shrinkage is more apparent,
+more lasting, and of more consequence to the architect,
+builder, or owner than the slight expansion which takes
+place, as, although the amount of moisture contained in
+wood varies with the climate conditions, the consequence
+of dampness or moisture on good timber used in houses
+only makes itself apparent by the occasional jamming of a
+door or window in wet or damp weather.</p>
+
+<p>Considerable expansion, however, takes place in the
+wood-paving of streets, and when this form of paving
+was in its infancy much trouble occurred owing to all
+allowances not having been made for this contingency,
+the trouble being doubtless increased owing to the blocks
+not being properly seasoned; curbing was lifted or pushed
+out of line and gully grids were broken by this action. As
+a rule in street paving a space of one or two inches wide
+is now left next to the curb, which is filled with sand or
+some soft material, so that the blocks may expand longitudinally
+without injuring the contour or affecting the curbs.
+But even with this arrangement it is not at all unusual
+for an inch or more to have to be cut off paving blocks
+parallel to the channels some time after the paving has<span class='pagenum'><a name="Page_136" id="Page_136">[136]</a></span>
+been laid, owing to the expansion of the wood exceeding
+the amounts allowed.</p>
+
+<p>Considerable variation occurs in the expansion of wood
+blocks, and it is noticeable in the hardwoods as well as in
+the softwoods, and is often greater in the former than in
+the latter.</p>
+
+<p>Expansion takes place in the direction of the length of
+the blocks as they are laid across the street, and causes
+no trouble in the other direction, the reason being that
+the lengthway of a block of wood is across the grain, of
+the timber, and it expands or contracts as a plank does.
+On one occasion, in a roadway forty feet wide, expansion
+occurred until it amounted to four inches on each side,
+or eight inches in all. This continual expansion and contraction
+is doubtless the cause of a considerable amount of
+wood street-paving bulging and becoming filled with
+ridges and depressions.</p>
+
+
+<h4>Elimination of Stain and Mildew</h4>
+
+<p>A great many manufacturers, and particularly those
+located in the Southern States, experience a great amount
+of difficulty in their timber becoming stained and mildewed.
+This is particularly true with gum wood, as it will
+frequently stain and mould in twenty-four hours, and
+they have experienced so much of this trouble that they
+have, in a great many instances, discontinued cutting it
+during the summer season.</p>
+
+<p>If this matter were given proper attention they should
+be able to eliminate a great deal of this difficulty, as no
+doubt they will find after investigation that the mould
+has been caused by the stock being improperly piled to
+the weather.</p>
+
+<p>Freshly sawn wood, placed in close piles during warm,
+damp weather in the months of July and August, presents
+especially favorable conditions for mould and stain. In
+all cases it is the moist condition and retarded drying of
+the wood which causes this. Therefore, any method which
+will provide for the rapid drying of the wood before or
+after piling will tend to prevent the difficulty, and the
+best method for eliminating mould is (1) to provide for<span class='pagenum'><a name="Page_137" id="Page_137">[137]</a></span>
+as little delay as possible between the felling of the tree,
+and its manufacture into rough products before the sap
+has had an opportunity of becoming sour. This is especially
+necessary with trees felled from April to September,
+in the region north of the Gulf States, and from March
+to November in the latter, while the late fall and winter
+cutting should all be worked up by March or April. (2)
+The material should be piled to the weather immediately
+after being sawn or cut, and every precaution should be
+taken in piling to facilitate rapid drying, by keeping the
+piles or ricks up off the ground. (3) All weeds (and emphasis
+should be placed on the <small>ALL</small>) and other vegetation
+should be kept well clear of the piles, in order that the
+air may have a clear and unobstructed passage through and
+around the piles, and (4) the piles should be so constructed
+that each stick or piece will have as much air space about
+it as it is possible to give to it.</p>
+
+<p>If the above instructions are properly carried out, there
+will be little or no difficulty experienced with mould appearing
+on the lumber.</p>
+
+
+
+<h3 style="padding-bottom: 0em"><a name="SECTION_IX" id="SECTION_IX"></a>SECTION IX<span class='pagenum'><a name="Page_138" id="Page_138">[138]</a></span></h3>
+
+<h2 style="padding-bottom: 1em">DIFFICULTIES OF DRYING
+WOOD</h2>
+
+
+<p><span class="smcap">Seasoning</span> and kiln-drying is so important a process in
+the manufacture of woods that a need is keenly felt for
+fuller information regarding it, based upon scientific study
+of the behavior of various species at different mechanical
+temperatures and under different mechanical drying processes.
+The special precautions necessary to prevent loss
+of strength or distortion of shape render the drying of
+wood especially difficult.</p>
+
+<p>All wood when undergoing a seasoning process, either
+natural (by air) or mechanical (by steam or heat in a dry
+kiln), checks or splits more or less. This is due to the
+uneven drying-out of the wood and the consequent strains
+exerted in opposite directions by the wood fibres in shrinking.
+This shrinkage, it has been proven, takes place both
+end-wise and across the grain of the wood. The old tradition
+that wood does not shrink end-wise has long since
+been shattered, and it has long been demonstrated that
+there is an end-wise shrinkage.</p>
+
+<p>In some woods it is very light, while in others it is easily
+perceptible. It is claimed that the average end shrinkage,
+taking all the woods, is only about 1<span class="above">1</span>&#8260;<span class="below">2</span> per cent. This,
+however, probably has relation to the average shrinkage
+on ordinary lumber as it is used and cut and dried. Now
+if we depart from this and take veneer, or basket stock,
+or even stave bolts where they are boiled, causing swelling
+both end-wise and across the grain or in dimension, after
+they are thoroughly dried, there is considerably more
+evidence of end shrinkage. In other words, a slack barrel
+stave of elm, say, 28 or 30 inches in length, after being<span class='pagenum'><a name="Page_139" id="Page_139">[139]</a></span>
+boiled might shrink as much in thoroughly drying-out
+as compared to its length when freshly cut, as a 12-foot
+elm board.</p>
+
+<p>It is in cutting veneer that this end shrinkage becomes
+most readily apparent. In trimming with scoring knives
+it is done to exact measure, and where stock is cut to fit
+some specific place there has been observed a shrinkage
+on some of the softer woods, like cottonwood, amounting
+to fully <span class="above">1</span>&#8260;<span class="below">8</span> of an inch in 36 inches. And at times where
+drying has been thorough the writer has noted a shrinkage
+of <span class="above">1</span>&#8260;<span class="below">8</span> of an inch on an ordinary elm cabbage-crate strip
+36 inches long, sawed from the log without boiling.</p>
+
+<p>There are really no fixed rules of measurement or allowance,
+however, because the same piece of wood may
+vary under different conditions, and, again, the grain
+may cross a little or wind around the tree, and this of
+itself has a decided effect on the amount of what is termed
+"end shrinkage."</p>
+
+<p>There is more checking in the wood of the broad-leaf
+(hardwood) trees than in that of the coniferous (softwood)
+trees, more in sapwood than in heartwood, and more in
+summer-wood than in spring-wood.</p>
+
+<p>Inasmuch as under normal conditions of weather, water
+evaporates less rapidly during the early seasoning of
+winter, wood that is cut in the autumn and early winter
+is considered less subject to checking than that which is
+cut in spring and summer.</p>
+
+<p>Rapid seasoning, except after wood has been thoroughly
+soaked or steamed, almost invariably results in more or
+less serious checking. All hardwoods which check or
+warp badly during the seasoning should be reduced to
+the smallest practicable size before drying to avoid the
+injuries involved in this process, and wood once seasoned
+<i>should never again be exposed to the weather</i>, since all injuries
+due to seasoning are thereby aggravated.</p>
+
+<p>Seasoning increases the strength of wood in every respect,
+and it is therefore of great importance to protect
+the wood against moisture.<span class='pagenum'><a name="Page_140" id="Page_140">[140]</a></span></p>
+
+
+<h4>Changes rendering Drying difficult</h4>
+
+<p>An important property rendering drying of wood peculiarly
+difficult is the changes which occur in the hygroscopic
+properties of the surface of a stick, and the rate
+at which it will allow moisture to pass through it. If
+wood is dried rapidly the surface soon reaches a condition
+where the transfusion is greatly hindered and sometimes
+appears almost to cease. The nature of this action is
+not well understood and it differs greatly in different species.
+Bald cypress (<i>Taxodium distichum</i>) is an example in which
+this property is particularly troublesome. The difficulty
+can be overcome by regulating the humidity during the
+drying operation. It is one of the factors entering into
+production of what is called "case-hardening" of wood,
+where the surface of the piece becomes hardened in a
+stretched or expanded condition, and subsequent shrinkage
+of the interior causes "honeycombing," "hollow-horning,"
+or internal checking. The outer surface of
+the wood appears to undergo a chemical change in the
+nature of hydrolization or oxidization, which alters the
+rate of absorption and evaporation in the air.</p>
+
+<p>As the total amount of shrinkage varies with the rate
+at which the wood is dried, it follows that the outer surface
+of a rapidly dried board shrinks less than the interior.
+This sets up an internal stress, which, if the board be
+afterward resawed into two thinner boards by slicing it
+through the middle, causes the two halves to cup with
+their convex surfaces outward. This effect may occur
+even though the moisture distribution in the board has
+reached a uniform condition, and the board is thoroughly
+dry before it is resawed. It is distinct from the well-known
+"case-hardening" effect spoken of above, which
+is caused by unequal moisture conditions.</p>
+
+<p>The manner in which the water passes from the interior
+of a piece of wood to its surface has not as yet been
+fully determined, although it is one of the most important
+factors which influence drying. This must involve a
+transfusion of moisture through the cell walls, since, as
+already mentioned, except for the open vessels in the hardwoods,<span class='pagenum'><a name="Page_141" id="Page_141">[141]</a></span>
+free resin ducts in the softwoods, and possibly the
+intercellular spaces, the cells of green wood are enclosed
+by membranes and the water must pass through the walls
+or the membranes of the pits. Heat appears to increase
+this transfusion, but experimental data are lacking.</p>
+
+<p>It is evident that to dry wood properly a great many
+factors must be taken into consideration aside from the
+mere evaporation of moisture.</p>
+
+
+<h4>Losses Due to Improper Kiln-drying</h4>
+
+<p>In some cases there is practically no loss in drying, but
+more often it ranges from 1 to 3 per cent, and 7 to 10 per
+cent in refractory woods such as gum. In exceptional
+instances the losses are as high as 33 per cent.</p>
+
+<p>In air-drying there is little or no control over the process;
+it may take place too rapidly on some days and too
+slowly on others, and it may be very non-uniform.</p>
+
+<p>Hardwoods in large sizes almost invariably check.</p>
+
+<p>By proper kiln-drying these unfavorable circumstances
+may be eliminated. However, air-drying is unquestionably
+to be preferred to bad kiln-drying, and when there
+is any doubt in the case it is generally safer to trust to
+air-drying.</p>
+
+<p>If the fundamental principles are all taken care of, green
+lumber can be better dried in the dry kiln.</p>
+
+
+<h4>Properties of Wood that affect Drying</h4>
+
+<p>It is clear, from the previous discussion of the structure
+of wood, that this property is of first importance among
+those influencing the seasoning of wood. The free water
+way usually be extracted quite readily from porous hardwoods.
+The presence of tyloses in white oak makes even
+this a difficult problem. On the other hand, its more
+complex structure usually renders the hygroscopic moisture
+quite difficult to extract.</p>
+
+<p>The lack of an open, porous structure renders the transfusion
+of moisture through some woods very slow, while
+the reverse may be true of other species. The point of
+interest is that all the different variations in structure<span class='pagenum'><a name="Page_142" id="Page_142">[142]</a></span>
+affect the drying rates of woods. The structure of the
+gums suggests relatively easy seasoning.</p>
+
+<p>Shrinkage is a very important factor affecting the drying
+of woods. Generally speaking, the greater the shrinkage
+the more difficult it is to dry wood. Wood shrinks
+about twice as much tangentially as radially, thus introducing
+very serious stresses which may cause loss in woods
+whose total shrinkage is large. It has been found that
+the amount of shrinkage depends, to some extent, on the
+rate and temperature at which woods season. Rapid
+drying at high or low temperature results in slight shrinkage,
+while slow drying, especially at high temperature,
+increases the shrinkage.</p>
+
+<p>As some woods must be dried in one way and others in
+other ways, to obtain the best general results, this effect
+may be for the best in one case and the reverse in others.
+As an example one might cite the case of Southern white
+oak. This species must be dried very slowly at low temperatures
+in order to avoid the many evils to which it is
+heir. It is interesting to note that this method tends to
+increase the shrinkage, so that one might logically expect
+such treatment merely to aggravate the evils. Such
+is not the case, however, as too fast drying results in other
+defects much worse than that of excessive shrinkage.</p>
+
+<p>Thus we see that the shrinkage of any given species of
+wood depends to a great extent on the method of drying.
+Just how much the shrinkage of gum is affected by the
+temperature and drying rate is not known at present.
+There is no doubt that the method of seasoning affects
+the shrinkage of the gums, however. It is just possible
+that these woods may shrink longitudinally more than
+is normal, thus furnishing another cause for their peculiar
+action under certain circumstances. It has been found
+that the properties of wood which affect the seasoning of
+the gums are, in the order of their importance: (1) The
+indeterminate and erratic grain; (2) the uneven shrinkage
+with the resultant opposing stresses; (3) the plasticity
+under high temperature while moist; and (4) the slight
+apparent lack of cohesion between the fibres. The first,
+second, and fourth properties are clearly detrimental,<span class='pagenum'><a name="Page_143" id="Page_143">[143]</a></span>
+while the third may possibly be an advantage in reducing
+checking and "case-hardening."</p>
+
+<p>The grain of the wood is a prominent factor also affecting
+the problem. It is this factor, coupled with uneven
+shrinkage, which is probably responsible, to a large extent,
+for the action of the gums in drying. The grain may be
+said to be more or less indeterminate. It is usually spiral,
+and the spiral may reverse from year to year of the tree's
+growth. When a board in which this condition exists
+begins to shrink, the result is the development of opposing
+stresses, the effect of which is sometimes disastrous. The
+shrinkage around the knots seems to be particularly uneven,
+so that checking at the knots is quite common.</p>
+
+<p>Some woods, such as Western red cedar, redwood, and
+eucalyptus, become very plastic when hot and moist.
+The result of drying-out the free water at high temperature
+may be to collapse the cells. The gums are known
+to be quite soft and plastic, if they are moist, at high
+temperature, but they do not collapse so far as we have
+been able to determine.</p>
+
+<p>The cells of certain species of wood appear to lack
+cohesion, especially at the junction between the annual
+rings. As a result, checks and ring shakes are very common
+in Western larch and hemlock. The parenchyma
+cells of the medullary rays in oak do not cohere strongly
+and often check open, especially when steamed too severely.</p>
+
+
+<h4>Unsolved Problems in Kiln-drying</h4>
+
+<div class="blockquot"><p>1. Physical data of the properties of wood in relation
+to heat are meagre.</p>
+
+<p>2. Figures on the specific heat of wood are not readily
+available, though upon this rests not only the exact
+operation of heating coils for kilns, but the
+theory of kiln-drying as a whole.</p>
+
+<p>3. Great divergence is shown in the results of experiments
+in the conductivity of wood. It remains
+to be seen whether the known variation of conductivity
+with moisture content will reduce these
+results to uniformity.<span class='pagenum'><a name="Page_144" id="Page_144">[144]</a></span></p>
+
+<p>4. The maximum or highest temperature to which
+the different species of wood may be exposed without
+serious loss of strength has not yet been determined.</p>
+
+<p>5. The optimum or absolute correct temperature for
+drying the different species of wood is as yet
+entirely unsettled.</p>
+
+<p>6. The inter-relation between wood and water is as
+imperfectly known to dry-kiln operators as that
+between wood and heat.</p>
+
+<p>7. What moisture conditions obtain in a stick of air-dried
+wood?</p>
+
+<p>8. How is the moisture distinguished?</p>
+
+<p>9. What is its form?</p>
+
+<p>10. What is the meaning of the peculiar surface conditions
+which even in air-dried wood appear to
+indicate incipient "case-hardening"?</p>
+
+<p>11. The manner in which the water passes from the
+interior of a piece of wood to its surface has not
+as yet been fully determined.</p></div>
+
+<p>These questions can be answered thus far only by speculation
+or, at best, on the basis of incomplete data.</p>
+
+<p>Until these problems are solved, kiln-drying must
+necessarily remain without the guidance of complete
+scientific theory.</p>
+
+<p>A correct understanding of the principles of drying is
+rare, and opinions in regard to the subject are very diverse.
+The same lack of knowledge exists in regard to dry kilns.
+The physical properties of the wood which complicate
+the drying operation and render it distinct from that of
+merely evaporating free water from some substance like
+a piece of cloth must be studied experimentally. It cannot
+well be worked out theoretically.</p>
+
+
+
+<h3 style="padding-bottom: 0em"><a name="SECTION_X" id="SECTION_X"></a>SECTION X<span class='pagenum'><a name="Page_145" id="Page_145">[145]</a></span></h3>
+
+<h2 style="padding-bottom: 1em">HOW WOOD IS SEASONED</h2>
+
+
+<h4>Methods of Drying</h4>
+
+<p><span class="smcap">The</span> choice of a method of drying depends largely upon
+the object in view. The principal objects may be grouped
+under three main heads, as follows:</p>
+
+<ul>
+<li>1. To reduce shipping weight.</li>
+<li>2. To reduce the quantity necessary to carry in stock.</li>
+
+<li>3. To prepare the wood for its ultimate use and improve
+its qualities.</li>
+</ul>
+
+
+<p>When wood will stand the temperature without excessive
+checking or undue shrinkage or loss in strength,
+the first object is most readily attained by heating the
+wood above the boiling point in a closed chamber, with
+a large circulation of air or vapor, so arranged that the
+excess steam produced will escape. This process manifestly
+does not apply to many of the hardwoods, but is
+applicable to many of the softwoods. It is used especially
+in the northwestern part of the United States, where
+Douglas fir boards one inch thick are dried in from 40 to
+65 hours, and sometimes in as short a time as 24 hours.
+In the latter case superheated steam at 300 degrees Fahrenheit
+was forced into the chamber but, of course, the
+lumber could not be heated thereby much above the boiling
+point so long as it contained any free water.</p>
+
+<p>This lumber, however, contained but 34 per cent moisture
+to start with, and the most rapid rate was 1.6 per cent
+loss per hour.</p>
+
+<p>The heat of evaporation may be supplied either by
+superheated steam or by steam pipes within the kiln
+itself.</p>
+
+<p>The quantity of wood it is necessary to carry in stock<span class='pagenum'><a name="Page_146" id="Page_146">[146]</a></span>
+is naturally reduced when either of the other two objects
+is attained and, therefore, need not necessarily be discussed.</p>
+
+<p>In drying to prepare for use and to improve quality,
+careful and scientific drying is called for. This applies
+more particularly to the hardwoods, although it may be
+required for softwoods also.</p>
+
+
+<h4>Drying at Atmospheric Pressure</h4>
+
+<p>Present practice of kiln-drying varies tremendously
+and there is no uniformity or standard method.</p>
+
+<p>Temperatures vary anywhere from 65 to 165 degrees
+Fahrenheit, or even higher, and inch boards three to six
+months on the sticks are being dried in from four days to
+three weeks, and three-inch material in from two to five
+months.</p>
+
+<p>All methods in use at atmospheric pressure may be
+classified under the following headings. The kilns may
+be either progressive or compartment, and preliminary
+steaming may or may not be used with any one of these
+methods:</p>
+
+<ul>
+<li>1. Dry air heated. This is generally obsolete.</li>
+
+<li>2. Moist air.</li>
+
+<li>
+<ul style="line-height: 130%"><li><i>a.</i> Ventilated.</li>
+
+<li><i>b.</i> Forced draft.</li>
+
+<li><i>c.</i> Condensing.</li>
+
+<li><i>d.</i> Humidity regulated.</li>
+
+<li><i>e.</i> Boiling.</li></ul>
+</li>
+<li>3. Superheated steam.</li>
+</ul>
+
+<h4>Drying under Pressure and Vacuum</h4>
+
+<p>Various methods of drying wood under pressures other
+than atmospheric have been tried. Only a brief mention
+of this subject will be made. Where the apparatus is
+available probably the quickest way to dry wood is first
+to heat it in saturated steam at as high a temperature
+as the species can endure without serious chemical change
+until the heat has penetrated to the center, then follow
+this with a vacuum.<span class='pagenum'><a name="Page_147" id="Page_147">[147]</a></span></p>
+
+<p>By this means the self-contained specific heat of the
+wood and the water is made available for the evaporation,
+and the drying takes place from the inside outwardly,
+just the reverse of that which occurs by drying by means
+of external heat.</p>
+
+<p>When the specimen has cooled this process is then to be
+repeated until it has dried down to fibre-saturation point.
+It cannot be dried much below this point by this method,
+since the absorption during the heating operation will
+then equal the evaporation during the cooling. It may
+be carried further, however, by heating in partially humidified
+air, proportioning the relative humidity each
+time it is heated to the degree of moisture present in the
+wood.</p>
+
+<p>The point to be considered in this operation is that
+during the heating process no evaporation shall be allowed
+to take place, but only during the cooling. In this way
+surface drying and "case-hardening" are prevented since
+the heat is from within and the moisture passes from the
+inside outwardly. However, with some species, notably
+oak, surface cracks appear as a network of fine checks
+along the medullary rays.</p>
+
+<p>In the first place, it should be borne in mind that it is
+the heat which produces evaporation and not the air nor
+any mysterious property assigned to a "vacuum."</p>
+
+<p>For every pound of water evaporated at ordinary temperatures
+approximately 1,000 British thermal units of
+heat are used up, or "become latent," as it is called. This
+is true whether the evaporation takes place in a vacuum
+or under a moderate air pressure. If this heat is not supplied
+from an outside source it must be supplied by the
+water itself (or the material being dried), the temperature
+of which will consequently fall until the surrounding
+space becomes saturated with vapor at a pressure corresponding
+to the temperature which the water has reached;
+evaporation will then cease. The pressure of the vapor
+in a space saturated with water vapor increases rapidly
+with increase of temperature. At a so-called vacuum of
+28 inches, which is about the limit in commercial operations,
+and in reality signifies an actual pressure of 2 inches<span class='pagenum'><a name="Page_148" id="Page_148">[148]</a></span>
+of mercury column, the space will be saturated with vapor
+at 101 degrees Fahrenheit. Consequently, no evaporation
+will take place in such a vacuum unless the water be
+warmer than 101 degrees Fahrenheit, provided there is
+no air leakage. The qualification in regard to air is necessary,
+for the sake of exactness, for the following reason:
+In any given space the total actual pressure is made up
+of the combined pressures of all the gases present. If the
+total pressure ("vacuum") is 2 inches, and there is no air
+present, it is all produced by the water vapor (which
+saturates the space at 101 degrees Fahrenheit); but if
+some air is present and the total pressure is still maintained
+at 2 inches, then there must be less vapor present, since
+the air is producing part of the pressure and the space is
+no longer saturated at the given temperature. Consequently
+further evaporation may occur, with a corresponding
+lowering of the temperature of the water, until a balance
+is again reached. Without further explanation it is easy
+to see that but little water can be evaporated by a vacuum
+alone without addition of heat, and that the prevalent
+idea that a vacuum can of itself produce evaporation is
+a fallacy. If heat be supplied to the water, however,
+either by conduction or radiation, evaporation will take
+place in direct proportion to the amount of heat supplied,
+so long as the pressure is kept down by the vacuum
+pump.</p>
+
+<p>At 30 inches of mercury pressure (one atmosphere) the
+space becomes saturated with vapor and equilibrium is
+established at 212 degrees Fahrenheit. If heat be now
+supplied to the water, however, evaporation will take
+place in proportion to the amount of heat supplied, so
+long as the pressure remains that of one atmosphere, just
+as in the case of the vacuum. Evaporation in this condition,
+where the vapor pressure at the temperature of
+the water is equal to the gas pressure on the water,
+is commonly called "boiling," and the saturated vapor
+entirely displaces the air under continuous operation.
+Whenever the space is not saturated with vapor, whether
+air is present or not, evaporation will take place, by boiling
+if no air be present or by diffusion under the presence<span class='pagenum'><a name="Page_149" id="Page_149">[149]</a></span>
+of air, until an equilibrium between temperature and
+vapor pressure is resumed.</p>
+
+<p>Relative humidity is simply the ratio of the actual vapor
+pressure present in a given space to the vapor pressure
+when the space is saturated with vapor at the given temperature.
+It matters not whether air be present or not.
+One hundred per cent humidity means that the space
+contains all the vapor which it can hold at the given
+temperature&mdash;it is saturated. Thus at 100 per cent
+humidity and 212 degrees Fahrenheit the space is saturated,
+and since the pressure of saturated vapor at this
+temperature is one atmosphere, no air can be present
+under these conditions. If, however, the total pressure
+at this temperature were 20 pounds (5 pounds gauge),
+then it would mean that there was 5 pounds air pressure
+present in addition to the vapor, yet the space would still
+be saturated at the given temperature. Again, if the
+temperature were 101 degrees Fahrenheit, the pressure
+of saturated vapor would be only 1 pound, and the additional
+pressure of 14 pounds, if the total pressure were
+atmospheric, would be made up of air. In order to have
+no air present and the space still saturated at 101 degrees
+Fahrenheit, the total pressure must be reduced to 1 pound
+by a vacuum pump. Fifty per cent relative humidity,
+therefore, signifies that only half the amount of vapor
+required to saturate the space at the given temperature
+is present. Thus at 212 degrees Fahrenheit temperature
+the vapor pressure would only be 7<span class="above">1</span>&#8260;<span class="below">2</span>pounds (vacuum of
+15 inches gauge). If the total pressure were atmospheric,
+then the additional 7<span class="above">1</span>&#8260;<span class="below">2</span> pounds would be simply air.</p>
+
+<p>"Live steam" is simply water-saturated vapor at a
+pressure usually above atmospheric. We may just as
+truly have live steam at pressures less than atmospheric,
+at a vacuum of 28 inches for instance. Only in the latter
+case its temperature would be lower, <i>viz.</i>, 101 degrees
+Fahrenheit.</p>
+
+<p>Superheated steam is nothing more than water vapor
+at a relative humidity less than saturation, but is usually
+considered at pressures above atmospheric, and in the
+absence of air. The atmosphere at, say, 50 per cent relative<span class='pagenum'><a name="Page_150" id="Page_150">[150]</a></span>
+humidity really contains superheated steam or vapor,
+the only difference being that it is at a lower temperature
+and pressure than we are accustomed to think of in speaking
+of superheated steam, and it has air mixed with it to
+make up the deficiency in pressure below the atmosphere.</p>
+
+<p>Two things should now be clear; that evaporation is
+produced by heat and that the presence or absence of air
+does not influence the amount of evaporation. It does,
+however, influence the rate of evaporation, which is retarded
+by the presence of air. The main things influencing
+evaporation are, first, the quantity of heat supplied
+and, second, the relative humidity of the immediately
+surrounding space.</p>
+
+
+<h4>Drying by Superheated Steam</h4>
+
+<p>What this term really signifies is simply water vapor
+in the absence of air in a condition of less than saturation.
+Kilns of this type are, properly speaking, vapor kilns,
+and usually operate at atmospheric pressure, but may be
+used at greater pressures or at less pressures. As stated
+before, the vapor present in the air at any humidity less
+than saturation is really "superheated steam," only at a
+lower pressure than is ordinarily understood by this term,
+and mixed with air. The main argument in favor of this
+process seems to be based on the idea that steam is moist
+heat. This is true, however, only when the steam is near
+saturation. When it is superheated it is just as dry as
+air containing the same relative humidity. For instance,
+steam at atmospheric pressure and heated to 248 degrees
+Fahrenheit has a relative humidity of only 50 per cent and
+is just as dry as air containing the same humidity. If
+heated to 306 degrees Fahrenheit, its relative humidity
+is reduced to 20 per cent; that is to say, the ratio of its
+actual vapor pressure (one atmosphere) to the pressure
+of saturated vapor at this temperature (five atmospheres)
+is 1:5, or 20 per cent. Superheated vapor in the absence
+of air, however, parts with its heat with great rapidity
+and finally becomes saturated when it has lost all of its
+ability to cause evaporation. In this respect it is more
+moist than air when it comes in contact with bodies which<span class='pagenum'><a name="Page_151" id="Page_151">[151]</a></span>
+are at a lower temperature. When saturated steam is
+used to heat the lumber it can raise the temperature of
+the latter to its own temperature, but cannot produce
+evaporation unless, indeed, the pressure is varied. Only
+by the heat supplied above the temperature of saturation
+can evaporation be produced.</p>
+
+
+<h4>Impregnation Methods</h4>
+
+<p>Methods of partially overcoming the shrinkage by impregnation
+of the cell walls with organic materials closely
+allied to the wood substance itself are in use. In one of
+these which has been patented, sugar is used as the impregnating
+material, which is subsequently hardened or
+"caramelized" by heating. Experiments which the United
+States Forest Service has made substantiate the claims
+that the sugar does greatly reduce the shrinkage of the
+wood; but the use of impregnation processes is determined
+rather from a financial economic standpoint than by the
+physical result obtained.</p>
+
+<p>Another process consists in passing a current of electricity
+through the wet boards or through the green logs
+before sawing. It is said that the ligno cellulose and the
+sap are thus transformed by electrolysis, and that the
+wood subsequently dries more rapidly.</p>
+
+
+<h4>Preliminary Treatments</h4>
+
+<p>In many dry kiln operations, especially where the kilns
+are not designed for treatments with very moist air, the
+wood is allowed to air-season from several months to a
+year or more before running it into the dry kiln. In this
+way the surface dries below its fibre-saturation point and
+becomes hardened or "set" and the subsequent shrinkage
+is not so great. Moreover, there is less danger of
+surface checking in the kiln, since the surface has already
+passed the danger point. Many woods, however, check
+severely in air-drying or case-harden in the air. It is
+thought that such woods can be satisfactorily handled in
+a humidity-regulated kiln direct from the saw.</p>
+
+<p>Preliminary steaming is frequently used to moisten the
+surface if case-hardened, and to heat the lumber through<span class='pagenum'><a name="Page_152" id="Page_152">[152]</a></span>
+to the center before drying begins. This is sometimes
+done in a separate chamber, but more often in a compartment
+of the kiln itself, partitioned off by means of a
+curtain which can be raised or lowered as circumstances
+require. This steaming is usually conducted at atmospheric
+pressure and frequently condensed steam is used
+at temperatures far below 212 degrees Fahrenheit. In
+a humidity-regulated kiln this preliminary treatment may
+be omitted, since nearly saturated conditions can be
+maintained and graduated as the drying progresses.</p>
+
+<p>Recently the process of steaming at pressures up to
+20 pounds gauge in a cylinder for short periods of time,
+varying from 5 to 20 minutes, is being advocated in the
+United States. The truck load is run into the cylinder,
+steamed, and then taken directly out into the air. It
+may subsequently be placed in the dry kiln if further drying
+is desired. The self-contained heat of the wood evaporates
+considerable moisture, and the sudden drying of
+the boards causes the shrinkage to be reduced slightly
+in some cases. Such short periods of steaming under
+20 pounds pressure do not appear to injure the wood
+mechanically, although they do darken the color appreciably,
+especially of the sapwood of the species having a
+light-colored sap, as black walnut (<i>Juglans nigra</i>) and
+red gum (<i>Liquidamber styraciflua</i>). Longer periods of
+steaming have been found to weaken the wood. There
+is a great difference in the effect on different species,
+however.</p>
+
+<p>Soaking wood for a long time before drying has been
+practised, but experiments indicate that no particularly
+beneficial results, from the drying standpoint, are attained
+thereby. In fact, in some species containing sugars and
+allied substances it is probably detrimental from the
+shrinkage standpoint. If soaked in boiling water some
+species shrink and warp more than if dried without this
+treatment.</p>
+
+<p>In general, it may be said that, except possibly for
+short-period steaming as described above, steaming and
+soaking hardwoods at temperatures of 212 degrees Fahrenheit
+or over should be avoided if possible.<span class='pagenum'><a name="Page_153" id="Page_153">[153]</a></span></p>
+
+<p>It is the old saying that wood put into water shortly
+after it is felled, and left in water for a year or more, will
+be perfectly seasoned after a short subsequent exposure
+to the air. For this reason rivermen maintain that
+timber is made better by rafting. Herzenstein says:
+"Floating the timber down rivers helps to wash out the
+sap, and hence must be considered as favorable to its
+preservation, the more so as it enables it to absorb more
+preservative."</p>
+
+<p>Wood which has been buried in swamps is eagerly
+sought after by carpenters and joiners, because it has
+lost all tendency to warp and twist. When first taken
+from the swamp the long-immersed logs are very much
+heavier than water, but they dry with great rapidity.
+A cypress log from the Mississippi Delta, which two men
+could barely handle at the time it was taken out some
+years ago, has dried out so much since then that to-day
+one man can lift it with ease. White cedar telegraph
+poles are said to remain floating in the water of the Great
+Lakes sometimes for several years before they are set in
+lines and to last better than freshly cut poles.</p>
+
+<p>It is very probable that immersion for long periods in
+water does materially hasten subsequent seasoning. The
+tannins, resins, albuminous materials, etc., which are
+deposited in the cell walls of the fibres of green wood, and
+which prevent rapid evaporation of the water, undergo
+changes when under water, probably due to the action of
+bacteria which live without air, and in the course of time
+many of these substances are leached out of the wood.
+The cells thereby become more and more permeable to
+water, and when the wood is finally brought into the air
+the water escapes very rapidly and very evenly. Herzenstein's
+statement that wood prepared by immersion
+and subsequent drying will absorb more preservative,
+and that with greater rapidity, is certainly borne out by
+experience in the United States.</p>
+
+<p>It is sometimes claimed that all seasoning preparatory
+to treatment with a substance like tar oil might be done
+away with by putting the green wood into a cylinder with
+the oil and heating to 225 degrees Fahrenheit, thus driving<span class='pagenum'><a name="Page_154" id="Page_154">[154]</a></span>
+the water off in the form of steam, after which the tar oil
+would readily penetrate into the wood. This is the basis
+of the so-called "Curtiss process" of timber treatment.
+Without going into any discussion of this method of
+creosoting, it may be said that the same objection made
+for steaming holds here. In order to get a temperature of
+212 degrees Fahrenheit in the center of the treated wood,
+the outside temperature would have to be raised so high
+that the strength of the wood might be seriously injured.</p>
+
+<p>A company on the Pacific coast which treats red fir piling
+asserts that it avoids this danger by leaving the green
+timber in the tar oil at a temperature which never exceeds
+225 degrees Fahrenheit for from five to twelve hours, until
+there is no further evidence of water vapor coming out of
+the wood. The tar oil is then run out, and a vacuum is
+created for about an hour, after which the oil is run in
+again and is kept in the cylinders under 100 pounds pressure
+for from ten to twelve hours, until the required amount
+of absorption has been reached (about 12 pounds per
+cubic foot).</p>
+
+
+<h4>Out-of-door Seasoning</h4>
+
+<p>The most effective seasoning is without doubt that
+obtained by the uniform, slow drying which takes place
+in properly constructed piles outdoors, under exposure
+to the winds and the sun. Lumber has always been
+seasoned in this way, which is still the best for ordinary
+purposes.</p>
+
+<p>It is probable for the sake of economy, air-drying will
+be eliminated in the drying process of the future without
+loss to the quality of the product, but as yet no effective
+method has been discovered whereby this may be accomplished,
+because nature performs certain functions
+in air-drying that cannot be duplicated by artificial means.
+Because of this, hardwoods, as a rule, cannot be successfully
+kiln-dried green or direct from the saw, and must
+receive a certain amount of preliminary air-drying before
+being placed in a dry kiln.</p>
+
+<p>The present methods of air-seasoning in use have been
+determined by long experience, and are probably as good<span class='pagenum'><a name="Page_155" id="Page_155">[155]</a></span>
+as they could be made for present conditions. But the
+same care has not up to this time been given to the seasoning
+of such timber as ties, bridge material, posts, telegraph
+and telephone poles, etc. These have sometimes been
+piled more or less intelligently, but in the majority of
+cases their value has been too low to make it seem worth
+while to pile with reference to anything beyond convenience
+in handling.</p>
+
+<p>In piling material for air-seasoning, one should utilize
+high, dry ground when possible, and see that the foundations
+are high enough off the ground, so that there is
+proper air circulation through the bottom of the piles,
+and also that the piles are far enough apart so that the
+air may circulate freely through and around them.</p>
+
+<p>It is air circulation that is desired in all cases of drying,
+both in dry kilns and out-of-doors, and not sunshine; that
+is, not the sun shining directly upon the material. The
+ends also should be protected from the sun, and everything
+possible done to induce a free circulation of air, and
+to keep the foundations free from all plant growth.</p>
+
+<p>Naturally, the heavier the material to be dried, the more
+difficulty is experienced from checking, which has its most
+active time in the spring when the sap is rising. In fact
+the main period of danger in material checking comes
+with the March winds and the April showers, and not
+infrequently in the South it occurs earlier than that. In
+other words, as soon as the sap begins to rise, the timber
+shows signs of checking, and that is the time to take extra
+precautions by careful piling and protection from the sun.
+When the hot days of summer arrive the tendency to
+check is not so bad, but stock will sour from the heat,
+stain from the sap, mildew from moisture, and fall a prey
+to wood-destroying insects.</p>
+
+<p>It has been proven in a general way that wood will
+season more slowly in winter than in summer, and also
+that the water content during various months varies. In
+the spring the drying-out of wood cut in October and
+November will take place more rapidly.</p>
+
+
+
+<h3 style="padding-bottom: 0em"><a name="SECTION_XI" id="SECTION_XI"></a>SECTION XI<span class='pagenum'><a name="Page_156" id="Page_156">[156]</a></span></h3>
+
+<h2 style="padding-bottom: 1em">KILN-DRYING OF WOOD</h2>
+
+
+<h4>Advantages of Kiln-drying over Air-drying</h4>
+
+<p><span class="smcap">Some</span> of the advantages of kiln-drying to be secured
+over air-drying in addition to reducing the shipping weight
+and lessening quantity of stock are the following:</p>
+
+<ul><li>1. Less material lost.</li>
+
+<li>2. Better quality of product.</li>
+
+<li>3. Prevention of sap stain and mould.</li>
+
+<li>4. Fixation of gums and resins.</li>
+
+<li>5. Reduction of hygroscopicity.</li></ul>
+
+
+<p>This reduction in the tendency to take up moisture
+means a reduction in the "working" of the material which,
+even though slight, is of importance.</p>
+
+<p>The problem of drying wood in the best manner divides
+itself into two distinct parts, one of which is entirely concerned
+with the behavior of the wood itself and the physical
+phenomena involved, while the other part has to do
+with the control of the drying process.</p>
+
+
+<h4>Physical Conditions governing the Drying of Wood</h4>
+
+<div class="blockquot"><p>1. Wood is soft and plastic while hot and moist, and
+becomes "set" in whatever shape it dries. Some
+species are much more plastic than others.</p>
+
+<p>2. Wood substance begins to shrink only when it dries
+below the fibre-saturation point, at which it contains
+from 25 to 30 per cent moisture based on
+its dry weight. Eucalyptus and certain other species
+appear to be exceptions to this law.</p>
+
+<p>3. The shrinkage of wood is about twice as great circumferentially
+as in the radial direction; lengthwise,
+it is very slight.</p>
+
+<p>4. Wood shrinks most when subjected, while kept
+moist, to slow drying at high temperatures.<span class='pagenum'><a name="Page_157" id="Page_157">[157]</a></span></p>
+
+<p>5. Rapid drying produces less shrinkage than slow drying
+at high temperatures, but is apt to cause case-hardening
+and honeycombing, especially in dense
+woods.</p>
+
+<p>6. Case-hardening, honeycombing, and cupping result
+directly from conditions 1, 4, and 5, and chemical
+changes of the outer surface.</p>
+
+<p>7. Brittleness is caused by carrying the drying process
+too far, or by using too high temperatures. Safe
+limits of treatment vary greatly for different species.</p>
+
+<p>8. Wood absorbs or loses moisture in proportion to the
+relative humidity in the air, not according to the
+temperature. This property is called its "hygroscopicity."</p>
+
+<p>9. Hygroscopicity and "working" are reduced but
+not eliminated by thorough drying.</p>
+
+<p>10. Moisture tends to transfuse from the hot towards
+the cold portion of the wood.</p>
+
+<p>11. Collapse of the cells may occur in some species
+while the wood is hot and plastic. This collapse
+is independent of subsequent shrinkage.</p></div>
+
+
+<h4>Theory of Kiln-drying</h4>
+
+<p>The dry kiln has long since acquired particular appreciation
+at the hands of those who have witnessed its
+time-saving qualities, when practically applied to the drying
+of timber. The science of drying is itself of the simplest,
+the exposure to the air being, indeed, the only means
+needed where the matter of time is not called into question.
+Otherwise, where hours, even minutes, have a marked
+significance, then other means must be introduced to
+bring about the desired effect. In any event, however,
+the same simple and natural remedy pertains,&mdash;the
+absorption of moisture. This moisture in green timber
+is known as "sap", which is itself composed of a number
+of ingredients, most important among which are water,
+resin, and albumen.</p>
+
+<p>All dry kilns in existence use heat to season timber;<span class='pagenum'><a name="Page_158" id="Page_158">[158]</a></span>
+that is, to drive out that portion of the "sap" which is
+volatile.</p>
+
+<p>The heat does not drive out the resin of the pines nor
+the albumen of the hardwoods. It is really of no advantage
+in this respect. Resin in its hardened state as
+produced by heat is only slowly soluble in water and
+contains a large proportion of carbon, the most stable
+form of matter. Therefore, its retention in the pores of
+the wood is a positive advantage.</p>
+
+<p>To produce the ideal effect the drying must commence
+at the heart of the piece and work outward, the moisture
+being removed from the surface as fast as it exudes from
+the pores of the wood. To successfully accomplish this,
+adjustments must be available to regulate the temperature,
+circulation, and humidity according to the variations
+of the atmospheric conditions, the kind and condition
+of the material to be dried.</p>
+
+<p>This ideal effect is only attained by the use of a type
+of dry kiln in which the surface of the lumber is kept soft,
+the pores being left open until all the moisture within has
+been volatilized by the heat and carried off by a free circulation
+of air. When the moisture has been removed from
+the pores, the surface is dried without closing the pores,
+resulting in timber that is clean, soft, bright, straight, and
+absolutely free from stains, checks, or other imperfections.</p>
+
+<p>Now, no matter how the method of drying may be
+applied, it must be remembered that vapor exists in the
+atmosphere at all times, its volume being regulated by
+the capacity of the temperature absorbed. To kiln-dry
+properly, a free current of air must be maintained, of
+sufficient volume to carry off this moisture. Now, the
+capacity of this air for drying depends entirely upon the
+ability of its temperature to absorb or carry off a larger
+proportion of moisture than that apportioned by natural
+means. Thus, it will be seen, a cubic foot of air at 32
+degrees Fahrenheit is capable of absorbing only two grains
+of water, while at 160 degrees, it will dispose of ninety
+grains. The air, therefore, should be made as dry as
+possible and caused to move freely, so as to remove all
+moisture from the surface of the wood as soon as it appears.<span class='pagenum'><a name="Page_159" id="Page_159">[159]</a></span>
+Thus the heat effects a double purpose, not only increasing
+the rate of evaporation, but also the capacity of the
+air for absorption. Where these means are applied, which
+rely on the heat alone to accomplish this purpose, only that
+of the moisture which is volatile succumbs, while the albumen
+and resin becoming hardened under the treatment
+close up the pores of the wood. This latter result is
+oft-times accomplished while moisture yet remains and
+which in an enforced effort to escape bursts open the cells
+in which it has been confined and creates what is known
+as "checks."</p>
+
+<p>Therefore, taking the above facts into consideration,
+the essentials for the successful kiln-drying of wood may
+be enumerated as follows:</p>
+
+<div class="blockquot"><p>1. The evaporation from the surface of a stick should
+not exceed the rate at which the moisture transfuses
+from the interior to the surface.</p>
+
+<p>2. Drying should proceed uniformly at all points,
+otherwise extra stresses are set up in the wood,
+causing warping, etc.</p>
+
+<p>3. Heat should penetrate to the interior of the piece
+before drying begins.</p>
+
+<p>4. The humidity should be suited to the condition
+of the wood at the start and reduced in the proper
+ratio as drying progresses. With wet or green
+wood it should usually be held uniform at a degree
+which will prevent the surface from drying below
+its saturation point until all the free water has
+evaporated, then gradually reduced to remove the
+hygroscopic moisture.</p>
+
+<p>5. The temperature should be uniform and as high
+as the species under treatment will stand without
+excessive shrinkage, collapse, or checking.</p>
+
+<p>6. Rate of drying should be controlled by the amount
+of humidity in the air and not by the rate of circulation,
+which should be made ample at all times.</p>
+
+<p>7. In drying refractory hardwoods, such as oak, best
+results are obtained at a comparatively low temperature.<span class='pagenum'><a name="Page_160" id="Page_160">[160]</a></span>
+In more easily dried hardwoods, such as
+maple, and some of the more difficult softwoods,
+as cypress, the process may be hastened by a higher
+temperature but not above the boiling point. In
+many of the softwoods, the rate of drying may be
+very greatly increased by heating above the boiling
+point with a large circulation of vapor at atmospheric
+pressure.</p>
+
+<p>8. Unequal shrinkage between the exterior and interior
+portions of the wood and also unequal chemical
+changes must be guarded against by temperatures
+and humidities suited to the species in question
+to prevent subsequent cupping and warping.</p>
+
+<p>9. The degree of dryness attained should conform
+to the use to which the wood is put.</p>
+
+<p>10. Proper piling of the material and weighting to prevent
+warping are of great importance.</p></div>
+
+
+<h4>Requirements in a Satisfactory Dry Kiln</h4>
+
+<p>The requirements in a satisfactory dry kiln are:</p>
+
+<ul><li>1. Control of humidity at all times.</li>
+
+<li>2. Ample air circulation at all points.</li>
+
+<li>3. Uniform and proper temperatures.</li></ul>
+
+
+<p>In order to meet these requirements the United States
+Forestry Service has designed a kiln in which the humidity,
+temperature, and circulation can be controlled at all times.</p>
+
+<p>Briefly, it consists of a drying chamber with a partition
+on either side, making two narrow side chambers open
+top and bottom.</p>
+
+<p>The steam pipes are in the usual position underneath
+the material to be dried.</p>
+
+<p>At the top of the side chambers is a spray; at the bottom
+are gutters and an eliminator or set of baffle plates to
+separate the fine mist from the air.</p>
+
+<p>The spray accomplishes two things: It induces an increased
+circulation and it regulates the humidity. This is
+done by regulating the temperature of the spray water.</p>
+
+<p>The air under the heating coil is saturated at whatever<span class='pagenum'><a name="Page_161" id="Page_161">[161]</a></span>
+temperature is required. This temperature is the dew
+point of the air after it passes up into the drying chamber
+above the coils. Knowing the temperature in the drying
+room and the dew point, the relative humidity is thus
+determined.</p>
+
+<p>The relative humidity is simply the ratio of the vapor
+pressure at the dew point to the pressure of saturated
+vapor (see <a href="#Fig_30">Fig. 30</a>).</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_30" id="Fig_30"></a></p>
+<img src="images/fig30.jpg" width="500" height="457" alt="Section through United States Forestry Service Humidity-controlled
+Dry Kiln" title="Section through United States Forestry Service Humidity-controlled
+Dry Kiln" />
+
+<p class="caption">Fig. 30. Section through United States Forestry Service Humidity-controlled
+Dry Kiln.</p>
+</div>
+
+
+<h4>Theory and Description of the Forestry Service Kiln</h4>
+
+<p>The humidities and temperatures in the piles of lumber
+are largely dependent upon the circulation of air within
+the kiln. The temperature and humidity within the kiln,
+taken alone, are no criterion of the conditions of drying
+the pile of lumber if the circulation in any portion<span class='pagenum'><a name="Page_162" id="Page_162">[162]</a></span>
+is deficient. It is possible to have an extremely rapid circulation
+of air within the dry kiln itself and yet have
+stagnation within the individual piles, the air passing
+chiefly through open spaces and channels. Wherever
+stagnation exists or the movement of air is too sluggish
+the temperature will drop and the humidity increase,
+perhaps to the point of saturation.</p>
+
+<p>When in large kilns the forced circulation is in the opposite
+direction from that induced by the cooling of the
+air by the lumber, there is always more or less uncertainty
+as to the movement of the air through the piles. Even
+with the boards placed edge-wise, with stickers running
+vertically, and with the heating pipes beneath the lumber,
+it was found that although the air passed upward through
+most of the spaces it was actually descending through
+others, so that very unequal drying resulted. While
+edge piling would at first thought seem ideal for the freest
+circulation in an ordinary kiln with steam pipes below, it
+in fact produces an indeterminate condition; air columns
+may pass downward through some channels as well as upward
+through others, and probably stagnate in still others.
+Nevertheless, edge piling is greatly superior to flat piling
+where the heating system is below the lumber.</p>
+
+<p>From experiments and from study of conditions in
+commercial kilns the idea was developed of so arranging
+the parts of the kiln and the pile of lumber that advantage
+might be taken of this cooling of the air to assist the circulation.
+That this can be readily accomplished without
+doing away with the present features of regulation of
+humidity by means of a spray of water is clear from <a href="#Fig_30">Fig.
+30</a>, which shows a cross-section of the improved humidity-regulated
+dry kiln.</p>
+
+<p>In the form shown in the sketch a chamber or flue B
+runs through the center near the bottom. This flue is
+only about 6 or 7 feet in height and, together with the
+water spray F and the baffle plates DD, constitutes the
+humidity-control feature of the kiln. This control of
+humidity is affected by the temperature of the water
+used in the spray. This spray completely saturates the
+air in the flue B at whatever predetermined temperature<span class='pagenum'><a name="Page_163" id="Page_163">[163]</a></span>
+is required. The baffle plates DD are to separate all
+entrained particles of water from the air, so that it is delivered
+to the heaters in a saturated condition at the required
+temperature. This temperature is, therefore, the
+dew point of the air when heated above, and the method
+of humidity control may therefore be called the dew-point
+method. It is a very simple matter by means of the humidity
+diagram (see <a href="#Fig_93">Fig. 93</a>), or by a hygrodeik (<a href="#Fig_94">Fig. 94</a>),
+to determine what dew-point temperature is needed for
+any desired humidity above the heaters.</p>
+
+<p>Besides regulating the humidity the spray F also acts as
+an ejector and forces circulation of air through the flue B.
+The heating system H is concentrated near the outer
+walls, so as to heat the rising column of air. The temperature
+within the drying chamber is controlled by means
+of any suitable thermostat, actuating a valve on the main
+steam line. The lumber is piled in such a way that the
+stickers slope downward toward the sides of the kiln.</p>
+
+<p>M is an auxiliary steam spray pointing downward for
+use at very high temperatures. C is a gutter to catch
+the precipitation and conduct it back to the pump, the
+water being recirculated through the sprays. G is a pipe
+condenser for use toward the end of the drying operation.
+K is a baffle plate for diverting the heated air and at the
+same time shielding the under layers of boards from direct
+radiation of the steam pipes.</p>
+
+<p>The operation of the kiln is simple. The heated air
+rises above the pipes HH and between the piles of lumber.
+As it comes in contact with the piles, portions of it are
+cooled and pass downward and outward through the layers
+of boards into the space between the condensers GG.
+Here the column of cooled air descends into the spray flue
+B, where its velocity is increased by the force of the water
+spray. It then passes out from the baffle plates to the
+heaters and repeats the cycle.</p>
+
+<p>One of the greatest advantages of this natural circulation
+method is that the colder the lumber when placed in
+the kiln the greater is the movement produced, under the
+very conditions which call for the greatest circulation&mdash;just
+the opposite of the direct-circulation method. This<span class='pagenum'><a name="Page_164" id="Page_164">[164]</a></span>
+is a feature of the greatest importance in winter, when the
+lumber is put into the kiln in a frozen condition. One
+truckload of lumber at 60 per cent moisture may easily
+contain over 7,000 pounds of ice.</p>
+
+<p>In the matter of circulation the kiln is, in fact, seldom
+regulatory&mdash;the colder the lumber the greater the circulation
+produced, with the effect increased toward the cooler
+and wetter portions of the pile.</p>
+
+<p>Preliminary steaming may be used in connection with
+this kiln, but experiments indicate that ordinarily it is
+not desirable, since the high humidity which can be secured
+gives as good results, and being at as low a temperature
+as desired, much better results in the case of certain difficult
+woods like oak, eucalyptus, etc., are obtained.</p>
+
+<p>This kiln has another advantage in that its operation
+is entirely independent of outdoor atmospheric conditions,
+except that barometric pressure will effect it slightly.</p>
+
+
+<h4>KILN-DRYING</h4>
+
+<h4>Remarks</h4>
+
+<p>Drying is an essential part of the preparation of wood
+for manufacture. For a long time the only drying process
+used or known was air-drying, or the exposure of wood to
+the gradual drying influences of the open air, and is what
+has now been termed "preliminary seasoning." This
+method is without doubt the most successful and effective
+seasoning, because nature performs certain functions in
+air-drying that cannot be duplicated by artificial means.
+Because of this, hardwoods, as a rule, cannot be successfully
+kiln-dried green or direct from the saw.</p>
+
+<p>Within recent years, considerable interest is awakening
+among wood users in the operation of kiln-drying.
+The losses occasioned in air-drying and in improper kiln-drying,
+and the necessity for getting material dry as
+quickly as possible from the saw, for shipping purposes
+and also for manufacturing, are bringing about a realization
+of the importance of a technical knowledge of the
+subject.<span class='pagenum'><a name="Page_165" id="Page_165">[165]</a></span></p>
+
+<p>The losses which occur in air-drying wood, through
+checking, warping, staining, and rotting, are often greater
+than one would suppose. While correct statistics of this
+nature are difficult to obtain, some idea may be had of
+the amount of degrading of the better class of lumber.
+In the case of one species of soft wood, Western larch, it
+is commonly admitted that the best grades fall off sixty
+to seventy per cent in air-drying, and it is probable that
+the same is true in the case of Southern swamp oaks. In
+Western yellow pine, the loss is great, and in the Southern
+red gum, it is probably as much as thirty per cent. It
+may be said that in all species there is some loss in air-drying,
+but in some easily dried species such as spruce,
+hemlock, maple, etc., it is not so great.</p>
+
+<p>It would hardly be correct to state at the present time
+that this loss could be entirely prevented by proper methods
+of kiln-drying the green lumber, but it is safe to say that
+it can be greatly reduced.</p>
+
+<p>It is well where stock is kiln-dried direct from the saw
+or knife, after having first been steamed or boiled&mdash;as
+in the case of veneers, etc.,&mdash;to get them into the kiln
+while they are still warm, as they are then in good condition
+for kiln-drying, as the fibres of the wood are soft
+and the pores well opened, which will allow of forcing
+the evaporation of moisture without much damage being
+done to the material.</p>
+
+<p>With softwoods it is a common practice to kiln-dry
+direct from the saw. This procedure, however, is ill
+adapted for the hardwoods, in which it would produce
+such warping and checking as would greatly reduce the
+value of the product. Therefore, hardwoods, as a rule,
+are more or less thoroughly air-dried before being placed
+in the dry kiln, where the residue of moisture may be
+reduced to within three or four per cent, which is much
+lower than is possible by air-drying only.</p>
+
+<p>It is probable that for the sake of economy, air-drying
+will be eliminated in the drying processes of the future without
+loss to the quality of the product, but as yet no method
+has been discovered whereby this may be accomplished.</p>
+
+<p>The dry kiln has been, and probably still is, one of the<span class='pagenum'><a name="Page_166" id="Page_166">[166]</a></span>
+most troublesome factors arising from the development
+of the timber industry. In the earlier days, before power
+machinery for the working-up of timber products came
+into general use, dry kilns were unheard-of, air-drying
+or seasoning was then relied upon solely to furnish the
+craftsman with dry stock from which to manufacture his
+product. Even after machinery had made rapid and
+startling strides on its way to perfection, the dry kiln remained
+practically an unknown quantity, but gradually,
+as the industry developed and demand for dry material
+increased, the necessity for some more rapid and positive
+method of seasoning became apparent, and the subject of
+artificial drying began to receive the serious attention of
+the more progressive and energetic members of the craft.</p>
+
+<p>Kiln-drying which is an artificial method, originated
+in the effort to improve or shorten the process, by subjecting
+the wood to a high temperature or to a draught of
+heated air in a confined space or kiln. In so doing, time
+is saved and a certain degree of control over the drying
+operation is secured.</p>
+
+<p>The first efforts in the way of artificial drying were confined
+to aiding or hastening nature in the seasoning process
+by exposing the material to the direct heat from fires built
+in pits, over which the lumber was piled in a way to expose
+it to the heat rays of the fires below. This, of course,
+was a primitive, hazardous, and very unsatisfactory
+method, to say the least, but it marked the first step in
+the evolution of the present-day dry kiln, and in that
+particular only is it deserving of mention.</p>
+
+
+<h4>Underlying Principles</h4>
+
+<p>In addition to marking the first step in artificial drying,
+it illustrated also, in the simplest manner possible, the
+three underlying principles governing all drying problems:
+(1) The application of heat to evaporate or volatilize the
+water contained in the material; (2) with sufficient air
+in circulation to carry away in suspension the vapor thus
+liberated; and (3) with a certain amount of humidity
+present to prevent the surface from drying too rapidly
+while the heat is allowed to penetrate to the interior. The<span class='pagenum'><a name="Page_167" id="Page_167">[167]</a></span>
+last performs two distinct functions: (a) It makes the
+wood more permeable to the passage of the moisture
+from the interior of the wood to the surface, and (b) it
+supplies the latent heat necessary to evaporate the moisture
+after it reaches the surface. The air circulation
+is important in removing the moisture after it has
+been evaporated by the heat, and ventilation also
+serves the purpose of bringing the heat in contact with
+the wood. If, however, plain, dry heat is applied to the
+wood, the surface will become entirely dry before the interior
+moisture is even heated, let alone removed. This
+condition causes "case-hardening" or "hollow-horning."
+So it is very essential that sufficient humidity be maintained
+to prevent the surface from drying too rapidly,
+while the heat is allowed to penetrate to the interior.</p>
+
+<p>This humidity or moisture is originated by the evaporation
+from the drying wood, or by the admission of steam
+into the dry kiln by the use of steam spray pipes, and is
+absolutely necessary in the process of hastening the drying
+of wood. With green lumber it keeps the sap near
+the surface of the piece in a condition that allows the
+escape of the moisture from its interior; or, in other words,
+it prevents the outside from drying first, which would
+close the pores and cause case-hardening.</p>
+
+<p>The great amount of latent heat necessary to evaporate
+the water after it has reached the surface is shown by the
+fact that the evaporation of only one pound of water will
+extract approximately 66 degrees from 1,000 cubic feet
+of air, allowing the air to drop in temperature from 154 to
+84 degrees Fahrenheit. In addition to this amount of heat,
+the wood and the water must also be raised to the temperature
+at which the drying is to be accomplished.</p>
+
+<p>It matters not what type of dry kiln is used, source or
+application of heating medium, these underlying principles
+remain the same, and must be the first things considered
+in the design or selection of the equipment necessary for
+producing the three essentials of drying: Heat, humidity,
+and circulation.</p>
+
+<p>Although these principles constitute the basis of all
+drying problems and must, therefore, be continually<span class='pagenum'><a name="Page_168" id="Page_168">[168]</a></span>
+carried in mind in the consideration of them, it is equally
+necessary to have a comprehensive understanding of the
+characteristics of the materials to be dried, and its action
+during the drying process. All failures in the past, in
+the drying of timber products, can be directly attributed
+to either the kiln designer's neglect of these things, or his
+failure to carry them fully in mind in the consideration
+of his problems.</p>
+
+<p>Wood has characteristics very much different from those
+of other materials, and what little knowledge we have
+of it and its properties has been taken from the accumulated
+records of experience. The reason for this imperfect
+knowledge lies in the fact that wood is not a homogeneous
+material like the metals, but a complicated structure, and
+so variable that one stick will behave in a manner widely
+different from that of another, although it may have been
+cut from the same tree.</p>
+
+<p>The great variety of woods often makes the mere distinction
+of the kind or species of the tree most difficult.
+It is not uncommon to find men of long experience disagree
+as to the kind of tree a certain piece of lumber was
+cut from, and, in some cases, there is even a wide difference
+in the appearance and evidently the structure of
+timber cut from the same tree.</p>
+
+
+<h4>Objects of Kiln-drying</h4>
+
+<p>The objects of kiln-drying wood may be placed under
+three main headings: (1) To reduce shipping expenses;
+(2) to reduce the quantity necessary to maintain in stock;
+and (3) to reduce losses in air-drying and to properly
+prepare the wood for subsequent use. Item number 2
+naturally follows as a consequence of either 1 or 3. The
+reduction in weight on account of shipping expenses is
+of greatest significance with the Northwestern lumbermen
+in the case of Douglas fir, redwood, Western red cedar,
+sugar pine, bull pine, and other softwoods.</p>
+
+<p>Very rapid methods of rough drying are possible with
+some of these species, and are in use. High temperatures
+are used, and the water is sometimes boiled off from the
+wood by heating above 212 degrees Fahrenheit. These<span class='pagenum'><a name="Page_169" id="Page_169">[169]</a></span>
+high-temperature methods will not apply to the majority
+of hardwoods, however, nor to many of the softwoods.</p>
+
+<p>It must first of all be recognized that the drying of
+lumber is a totally different operation from the drying
+of a fabric or of thin material. In the latter, it is largely
+a matter of evaporated moisture, but wood is not only
+hygroscopic and attracts moisture from the air, but its
+physical behavior is very complex and renders the extraction
+of moisture a very complicated process.</p>
+
+<p>An idea of its complexity may be had by mentioning some
+of the conditions which must be contended with. Shrinkage
+is, perhaps, the most important. This is unequal
+in different directions, being twice as great tangentially
+as radially and fifty times as great radially as longitudinally.
+Moreover, shrinkage is often unequal in different
+portions of the same piece. The slowness of the transfusion
+of moisture through the wood is an important factor. This
+varies with different woods and greatly in different directions.
+Wood becomes soft and plastic when hot and moist,
+and will yield more or less to internal stresses. As some
+species are practically impervious to air when wet, this
+plasticity of the cell walls causes them to collapse as the
+water passes outward from the cell cavities. This difficulty
+has given much trouble in the case of Western red
+cedar, and also to some extent in redwood. The unequal
+shrinkage causes internal stresses in the wood as it dries,
+which results in warping, checking, case-hardening, and
+honeycombing. Case-hardening is one of the most common
+defects in improperly dried lumber. It is clearly
+shown by the cupping of the two halves when a case-hardened
+board is resawed. Chemical changes also occur
+in the wood in drying, especially so at higher temperatures,
+rendering it less hygroscopic, but more brittle. If dried
+too much or at too high a temperature, the strength and
+toughness is seriously reduced.</p>
+
+
+<h4>Conditions of Success</h4>
+
+<p>Commercial success in drying therefore requires that
+the substance be exposed to the air in the most efficient
+manner; that the temperature of the air be as high as the<span class='pagenum'><a name="Page_170" id="Page_170">[170]</a></span>
+substance will stand without injury, and that the air change
+or movement be as rapid as is consistent with economical
+installation and operation. Conditions of success therefore
+require the observance of the following points, which
+embody the basic principles of the process: (1) The
+timber should be heated through before drying begins.
+(2) The air should be very humid at the beginning of the
+drying process, and be made drier only gradually. (3) The
+temperature of the lumber must be maintained uniformly
+throughout the entire pile. (4) Control of the drying
+process at any given temperature must be secured by
+controlling the relative humidity, not by decreasing the
+circulation. (5) In general, high temperatures permit
+more rapid drying than do lower temperatures. The
+higher the temperature of the lumber, the more efficient
+is the kiln. It is believed that temperatures as high as
+the boiling point are not injurious to most woods, providing
+all other fundamentally important features are
+taken care of. Some species, however, are not able to
+stand as high temperatures as others, and (6) the degree
+of dryness attained, where strength is the prime requisite,
+should not exceed that at which the wood is to be used.</p>
+
+
+<h4>Different Treatment according to Kind</h4>
+
+<p>The rapidity with which water may be evaporated, that
+is, the rate of drying, depends on the size and shape of
+the piece and on the structure of the wood. Thin stock
+can be dried much faster than thick, under the same conditions
+of temperature, circulation, and humidity. Pine
+can be dried, as a general thing, in about one third of the
+time that would be required for oak of the same thickness,
+although the former contains the more water of the two.
+Quarter-sawn oak usually requires half again as long as
+plain oak. Mahogany requires about the same time as
+plain oak; ash dries in a little less time, and maple, according
+to the purpose for which it is intended, may be dried
+in one fifth the time needed for oak, or may require a
+slightly longer treatment. For birch, the time required
+is from one half to two thirds, and for poplar and basswood,
+from, one fifth to one third that required for oak.<span class='pagenum'><a name="Page_171" id="Page_171">[171]</a></span></p>
+
+<p>All kinds and thicknesses of lumber cannot be dried at
+the same time in the same kiln. It is manifest that green
+and air-dried lumber, dense and porous lumber, all require
+different treatment. For instance, Southern yellow
+pine when cut green from the log will stand a very high
+temperature, say 200 degrees Fahrenheit, and in fact this
+high temperature is necessary together with a rapid circulation
+of air in order to neutralize the acidity of the pitch
+which causes the wood to blue and discolor. This lumber
+requires to be heated up immediately and to be kept hot
+throughout the length of the kiln. Hence the kiln must
+not be of such length as to allow of the air being too much
+cooled before escaping.</p>
+
+
+<h4>Temperature depends</h4>
+
+<p>While it is true that a higher temperature can be carried
+in the kiln for drying pine and similar woods, this does
+not altogether account for the great difference in drying
+time, as experience has taught us that even when both
+woods are dried in the same kiln, under the same conditions,
+pine will still dry much faster, proving thereby that
+the structure of the wood itself affects drying.</p>
+
+<p>The aim of all kiln designers should be to dry in the
+shortest possible time, without injury to the material. Experience
+has demonstrated that high temperatures are very
+effective in evaporating water, regardless of the degree of
+humidity, but great care must be exercised in using extreme
+temperatures that the material to be dried is not
+damaged by checking, case-hardening, or hollow-horning.</p>
+
+<p>The temperature used should depend upon the species
+and condition of the material when entering the kiln. In
+general, it is advantageous to have as high a temperature
+as possible, both for economy of operation and speed of
+drying, but the physical properties of the wood will govern
+this.</p>
+
+<p>Many species cannot be dried satisfactorily at high
+temperatures on account of their peculiar behavior. This
+is particularly so with green lumber.</p>
+
+<p>Air-dried wood will stand a relatively higher temperature,
+as a rule, than wet or green wood. In drying green<span class='pagenum'><a name="Page_172" id="Page_172">[172]</a></span>
+wood direct from the saw, it is usually best to start with
+a comparatively low temperature, and not raise the temperature
+until the wood is nearly dry. For example,
+green maple containing about 60 per cent of its dry weight
+in water should be started at about 120 degrees Fahrenheit
+and when it reaches a dryness of 25 per cent, the temperature
+may be raised gradually up to 190 degrees.</p>
+
+<p>It is exceedingly important that the material be practically
+at the same temperature throughout if perfect
+drying is to be secured. It should be the same temperature
+in the center of a pile or car as on the outside, and
+the same in the center of each individual piece of wood
+as on its surface. This is the effect obtained by natural
+air-drying. The outside atmosphere and breezes (natural
+air circulation) are so ample that the heat extracted for
+drying does not appreciably change the temperature.</p>
+
+<p>When once the wood has been raised to a high temperature
+through and through and especially when the
+surface has been rendered most permeable to moisture,
+drying may proceed as rapidly as it can be forced by artificial
+circulation, provided the heat lost from the wood
+through vaporization is constantly replaced by the heat
+of the kiln.</p>
+
+<p>It is evident that to secure an even temperature, a free
+circulation of air must be brought in contact with the
+wood. It is also evident that in addition to heat and a
+circulation of air, the air must be charged with a certain
+amount of moisture to prevent surface drying or case-hardening.</p>
+
+<p>There are some twenty-five different makes of dry kilns
+on the market, which fulfill to a varying degree the fundamental
+requirements. Probably none of them succeed
+perfectly in fulfilling all.</p>
+
+<p>It is well to have the temperature of a dry kiln controlled
+by a thermostat which actuates the valve on the
+main steam supply pipe. It is doubly important to maintain
+a uniform temperature and avoid fluctuations in
+the dry kiln, since a change in temperature will greatly
+alter the relative humidity.</p>
+
+<p>In artificial drying, temperatures of from 150 to 180 degrees<span class='pagenum'><a name="Page_173" id="Page_173">[173]</a></span>
+Fahrenheit are usually employed. Pine, spruce,
+cypress, cedar, etc., are dried fresh from the saw, allowing
+four days for 1-inch stuff. Hardwoods, especially oak, ash,
+maple, birch, sycamore, etc., are usually air-seasoned for
+three to six months to allow the first shrinkage to take place
+more gradually, and are then exposed to the above temperatures
+in the kiln for about six to ten days for 1-inch
+stuff, other dimensions in proportion.</p>
+
+<p>Freshly cut poplar and cottonwood are often dried
+direct from the saw in a kiln. By employing lower temperatures,
+100 to 120 degrees Fahrenheit, green oak, ash,
+etc., can be seasoned in dry kilns without much injury to
+the material.</p>
+
+<p>Steaming and sweating the wood is sometimes resorted
+to in order to prevent checking and case-hardening, but
+not, as has been frequently asserted, to enable the material
+to dry.</p>
+
+
+<h4>Air Circulation</h4>
+
+<p>Air circulation is of the utmost importance, since no
+drying whatever can take place when it is lacking. The
+evaporation of moisture requires heat and this must be
+supplied by the circulating air. Moreover, the moisture
+laden air must be constantly removed and fresh, drier air
+substituted. Probably this is the factor which gives
+more trouble in commercial operations than anything
+else, and the one which causes the greatest number of
+failures.</p>
+
+<p>It is necessary that the air circulate through every
+part of the kiln and that the moving air come in contact
+with every portion of the material to be dried. In fact,
+the humidity is dependent upon the circulation. If the
+air stagnates in any portion of the pile, then the temperature
+will drop and the humidity rise to a condition of
+saturation. Drying will not take place at this portion
+of the pile and the material is apt to mould and rot.</p>
+
+<p>The method of piling the material on trucks or in the
+kiln, is therefore, of extreme importance. Various methods
+are in use. Ordinary flat piling is probably the poorest.
+Flat piling with open chimney spaces in the piles is better.<span class='pagenum'><a name="Page_174" id="Page_174">[174]</a></span>
+But neither method is suitable for a kiln in which the
+circulation is mainly vertical.</p>
+
+<p>Edge piling with stickers running vertically is in use
+in kilns when the heating coils are beneath. This is much
+better.</p>
+
+<p>Air being cooled as it comes in contact with a pile of
+material, becomes denser, and consequently tends to sink.
+Unless the material to be dried is so arranged that the
+air can pass gradually downward through the pile as it
+cools, poor circulation is apt to result.</p>
+
+<p>In edge-piled lumber, with the heating system beneath
+the piles, the natural tendency of the cooled air to descend
+is opposed by the hot air beneath which tends to rise.
+An indeterminate condition is thus brought about, resulting
+in non-uniform drying. It has been found that
+air will rise through some layers and descend through
+others.</p>
+
+
+<h4>Humidity</h4>
+
+<p>Humidity is of prime importance because the rate of
+drying and prevention of checking and case-hardening
+are largely dependent thereon. It is generally true that
+the surface of the wood should not dry more rapidly than
+the moisture transfuses from the center of the piece to
+its surface, otherwise disaster will result. As a sufficient
+amount of moisture is removed from the wood to maintain
+the desired humidity, it is not good economy to
+generate moisture in an outside apparatus and force it
+into a kiln, unless the moisture in the wood is not sufficient
+for this purpose; in that case provision should be made
+for adding any additional moisture that may be required.</p>
+
+<p>The rate of evaporation may best be controlled by
+controlling the amount of vapor present in the air (relative
+humidity); it should not be controlled by reducing the
+air circulation, since a large circulation is needed at all
+times to supply the necessary heat.</p>
+
+<p>The humidity should be graded from 100 per cent at
+the receiving end of the kiln, to whatever humidity corresponds
+with the desired degree of dryness at the delivery
+end.<span class='pagenum'><a name="Page_175" id="Page_175">[175]</a></span></p>
+
+<p>The kiln should be so designed that the proper degree
+may be maintained at its every section.</p>
+
+<p>A fresh piece of sapwood will lose weight in boiling
+water and can also be dried to quite an extent in steam.
+This proves conclusively that a high degree of humidity
+does not have the detrimental effect on drying that is
+commonly attributed to it. In fact, a proper degree of
+humidity, especially in the loading or receiving end of a
+kiln, is just as necessary to good results in drying as
+getting the proper temperature.</p>
+
+<p>Experiments have demonstrated also that injury to
+stock in the way of checking, warping, and hollow-horning
+always develops immediately after the stock is taken into
+the kiln, and is due to the degree of humidity being too
+low. The receiving end of the kiln should always be
+kept moist, where the stock has not been steamed before
+being put into the kiln. The reason for this is simple
+enough. When the air is too dry it tends to dry the outside
+of the material first&mdash;which is termed "case-hardening"&mdash;and
+in so doing shrinks and closes up the pores
+of the wood. As the stock is moved down the kiln, it
+absorbs a continually increasing amount of heat, which
+tends to drive off the moisture still present in the center
+of the stock. The pores on the outside having been closed
+up, there is no exit for the vapor or steam that is being
+rapidly formed in the center. It must find its way out
+some way, and in doing so sets up strains, which result
+either in checking, warping, or hollow-horning. If the
+humidity had been kept higher, the outside of the material
+would not have dried so quickly, and the pores would
+have remained open for the exit of moisture from the interior
+of the wood, and this trouble would have been
+avoided.</p>
+
+<p>Where the humidity is kept at a high point in the receiving
+end of the kiln, a higher rate of temperature may
+also be carried, and in that way the drying process is
+hastened with comparative safety.</p>
+
+<p>It is essential, therefore, to have an ample supply of
+heat through the convection currents of the air; but in
+the case of wood the rate of evaporation must be controlled,<span class='pagenum'><a name="Page_176" id="Page_176">[176]</a></span>
+else checking will occur. This can be done by
+means of the relative humidity, as stated before. It is
+clear now that when the air&mdash;or, more properly speaking,
+the space&mdash;is completely saturated no evaporation
+can take place at the given temperature. By reducing
+the humidity, evaporation takes place more and more
+rapidly.</p>
+
+<p>Another bad feature of an insufficient and non-uniform
+supply of heat is that each piece of wood will be heated to
+the evaporating point on the outer surface, the inside
+remaining cool until considerable drying has taken place
+from the surface. Ordinarily in dry kilns high humidity
+and large circulation of air are antitheses to one another.
+To obtain the high humidity the circulation is either
+stopped altogether or greatly reduced, and to reduce the
+humidity a greater circulation is induced by opening the
+ventilators or otherwise increasing the draft. This is
+evidently not good practice, but as a rule is unavoidable
+in most dry kilns of present make. The humidity should
+be raised to check evaporation without reducing the
+circulation if possible.</p>
+
+<p>While thin stock, such as cooperage and box stuff is
+less inclined to give trouble by undue checking than 1-inch
+and thicker, one will find that any dry kiln will give more
+uniform results and, at the same time, be more economical
+in the use of steam, when the humidity and temperature
+is carried at as high a point as possible without injury to
+the material to be dried.</p>
+
+<p>Any well-made dry kiln which will fulfill the conditions
+required as to circulation and humidity control should work
+satisfactorily; but each case must be studied by itself,
+and the various factors modified to suit the peculiar conditions
+of the problem in hand. In every new case the
+material should be constantly watched and studied and,
+if checking begins, the humidity should be increased until
+it stops. It is not reducing the circulation, but adding
+the necessary moisture to the air, that should be depended
+on to prevent checking. For this purpose it is well to
+have steam jets in the kiln so that if needed they are ready
+at hand.<span class='pagenum'><a name="Page_177" id="Page_177">[177]</a></span></p>
+
+
+<h4>Kiln-drying</h4>
+
+<p>There are two distinct ways of handling material in
+dry kilns. One way is to place the load of lumber in a
+chamber where it remains in the same place throughout
+the operation, while the conditions of the drying medium
+are varied as the drying progresses. This is the "apartment"
+kiln or stationary method. The other is to run
+the lumber in at one end of the chamber on a wheeled
+truck and gradually move it along until the drying process
+is completed, when it is taken out at the opposite end of
+the kiln. It is the usual custom in these kilns to maintain
+one end of the chamber moist and the other end
+dry. This is known as the "progressive" type of kiln,
+and is the one most commonly used in large operations.</p>
+
+<p>It is, however, the least satisfactory of the two where
+careful drying is required, since the conditions cannot
+be so well regulated and the temperatures and humidities
+are apt to change with any change of wind. The apartment
+method can be arranged so that it will not require any
+more kiln space or any more handling of lumber than the
+progressive type. It does, however, require more intelligent
+operation, since the conditions in the drying
+chamber must be changed as the drying progresses. With
+the progressive type the conditions, once properly established,
+remain the same.</p>
+
+<p>To obtain draft or circulation three methods are in use&mdash;by
+forced draft or a blower usually placed outside the kiln,
+by ventilation, and by internal circulation and condensation.
+A great many patents have been taken out on
+different methods of ventilation, but in actual operation
+few kilns work exactly as intended. Frequently the air
+moves in the reverse direction for which the ventilators
+were planned. Sometimes a condenser is used in connection
+with the blower and the air is recirculated. It is
+also&mdash;and more satisfactorily&mdash;used with the gentle
+internal-gravity currents of air.</p>
+
+<p>Many patents have been taken out for heating systems.
+The differences among these, however, have more to do
+the mechanical construction than with the process<span class='pagenum'><a name="Page_178" id="Page_178">[178]</a></span>
+of drying. In general, the heating is either direct or indirect.
+In the former steam coils are placed in the chamber
+with the lumber, and in the latter the air is heated by
+either steam coils or a furnace before it is introduced into
+the drying chamber.</p>
+
+<p>Moisture is sometimes supplied by means of free
+steam jets in the kiln or in the entering air; but more
+often the moisture evaporated from the lumber is relied
+upon to maintain the humidity necessary.</p>
+
+<p>A substance becomes dry by the evaporation of its
+inherent moisture into the surrounding space. If this
+space be confined it soon becomes saturated and the process
+stops. Hence, constant change is necessary in order
+that the moisture given off may be continually carried
+away.</p>
+
+<p>In practice, air movement, is therefore absolutely essential
+to the process of drying. Heat is merely a useful
+accessory which serves to decrease the time of drying
+by increasing both the rate of evaporation and the absorbing
+power of the surrounding space.</p>
+
+<p>It makes no difference whether this space is a vacuum
+or filled with air; under either condition it will take up
+a stated weight of vapor. From this it appears that the
+vapor molecules find sufficient space between the molecules
+of air. But the converse is not true, for somewhat less
+air will be contained in a given space saturated with vapor
+than in one devoid of moisture. In other words the air
+does not seem to find sufficient space between the molecules
+of vapor.</p>
+
+<p>If the temperature of the confined space be increased,
+opportunity will thereby be provided for the vaporization
+of more water, but if it be decreased, its capacity for
+moisture will be reduced and visible water will be deposited.
+The temperature at which this takes place is
+known as the "dew-point" and depends upon the initial
+degree of saturation of the given space; the less the relative
+saturation the lower the dew-point.</p>
+
+<p>Careful piling of the material to be dried, both in the
+yard and dry kiln, is essential to good results in drying.</p>
+
+<p>Air-dried material is not dry, and its moisture is too<span class='pagenum'><a name="Page_179" id="Page_179">[179]</a></span>
+unevenly distributed to insure good behavior after manufacture.</p>
+
+<p>It is quite a difficult matter to give specific or absolute
+correct weights of any species of timber when thoroughly
+or properly dried, in order that one may be guided in
+these kiln operations, as a great deal depends upon the
+species of wood to be dried, its density, and upon the
+thickness which it has been cut, and its condition when
+entering the drying chamber.</p>
+
+<p>Elm will naturally weigh less than beech, and where
+the wood is close-grained or compact it will weigh more
+than coarse-grained wood of the same species, and, therefore,
+no set rules can be laid down, as good judgment
+only should be used, as the quality of the drying is not
+purely one of time. Sometimes the comparatively slow
+process gives excellent results, while to rush a lot of stock
+through the kiln may be to turn it out so poorly seasoned
+that it will not give satisfaction when worked into the
+finished product. The mistreatment of the material in
+this respect results in numerous defects, chief among which
+are warping and twisting, checking, case-hardening, and
+honeycombing, or, as sometimes called, hollow-horning.</p>
+
+<p>Since the proportion of sap and heartwood varies with
+size, age, species, and individual trees, the following figures
+as regards weight must be regarded as mere approximations:</p>
+
+
+<p class="center"><span class="smcap">Pounds of Water Lost in Drying 100 Pounds of Green Wood
+in the Kiln</span></p>
+
+<table summary="pounds of water lost in drying" cellpadding="2" class="kilnwood">
+<tr><td style="border-bottom: solid black 1px">&nbsp;</td><td class="centered">Sapwood or<br /> outer part</td><td class="centered">Heartwood<br /> or interior</td></tr>
+<tr><td class="tableentry">(1) Pine, cedar, spruce, and fir</td><td class="centered2">45-65</td><td class="centered2">6-25</td></tr>
+<tr><td class="tableentry">(2) Cypress, extremely variable</td><td class="centered2">50-65</td><td class="centered2">18-60</td></tr>
+<tr><td class="tableentry">(3) Poplar, cottonwood, and basswood</td><td class="centered2">60-65</td><td class="centered2">40-60</td></tr>
+<tr><td class="tableentry">(4) Oak, beech, ash, maple, birch, elm, hickory,
+chestnut, walnut, and sycamore</td><td class="centered2" style="vertical-align: bottom">40-50</td><td class="centered2" style="vertical-align: bottom">30-40</td></tr>
+</table>
+
+<p>The lighter kinds have the most water in the sapwood;
+thus sycamore has more water than hickory, etc.</p>
+
+<p>The efficiency of the drying operations depends a great<span class='pagenum'><a name="Page_180" id="Page_180">[180]</a></span>
+deal upon the way in which, the lumber is piled, especially
+when the humidity is not regulated. From the theory
+of drying it is evident that the rate of evaporation in dry
+kilns where the humidity is not regulated depends entirely
+upon the rate of circulation, other things being equal.
+Consequently, those portions of the wood which receive
+the greatest amount of air dry the most rapidly, and
+vice versa. The only way, therefore, in which anything
+like uniform drying can take place is where the lumber is
+so piled that each portion of it comes in contact with the
+same amount of air.</p>
+
+<p>In the Forestry Service kiln (<a href="#Fig_30">Fig. 30</a>), where the degree of
+relative humidity is used to control the rate of drying,
+the amount of circulation makes little difference, provided
+it exceeds a certain amount. It is desirable to pile
+the lumber so as to offer as little frictional resistance as
+possible and at the same time secure uniform circulation.
+If circulation is excessive in any place it simply means
+waste of energy but no other injury to the lumber.</p>
+
+<p>The best method of piling is one which permits the
+heated air to pass through the pile in a somewhat downward
+direction. The natural tendency of the cooled air
+to descend is thus taken advantage of in assisting the
+circulation in the kiln. This is especially important when
+cold or green lumber is first introduced into the kiln.
+But even when the lumber has become warmed the cooling
+due to the evaporation increases the density of the
+mixture of the air and vapor.</p>
+
+
+<h4>Kiln-drying Gum</h4>
+
+<p>The following article was published by the United
+States Forestry Service as to the best method of kiln-drying
+gum:</p>
+
+<p><b>Piling.</b>&mdash;Perhaps the most important factor in good kiln-drying,
+especially in the case of the gums, is the method of
+piling. It is our opinion that proper and very careful piling
+will greatly reduce the loss due to warping. A good method
+of piling is to place the lumber lengthwise of the kiln and
+on an incline cross-wise. The warm air should rise at<span class='pagenum'><a name="Page_181" id="Page_181">[181]</a></span>
+the higher side of the pile and descend between the courses
+of lumber. The reason for this is very simple and the
+principle has been applied in the manufacture of the best
+ice boxes for some time. The most efficient refrigerators
+are iced at the side, the ice compartment opening to the
+cooling chamber at the top and bottom. The warm air
+from above is cooled by melting the ice. It then becomes
+denser and settles down into the main chamber. The
+articles in the cooling room warm the air as they cool, so
+it rises to the top and again comes in contact with the
+ice, thus completing the cycle. The rate of this natural
+circulation is automatically regulated by the temperature
+of the articles in the cooling chamber and by the amount
+of ice in the icing compartment; hence the efficiency of
+such a box is high.</p>
+
+<p>Now let us apply this principle to the drying of lumber.
+First we must understand that as long as the lumber is
+moist and drying, it will always be cooler than the surrounding
+air, the amount of this difference being determined
+by the rate of drying and the moisture in the wood. As
+the lumber dries, its temperature gradually rises until it
+is equal to that of the air, when perfect dryness results.
+With this fact in mind it is clear that the function of the
+lumber in a kiln is exactly analogous to that of the ice in
+an ice box; that is, it is the cooling agent. Similarly,
+the heating pipes in a dry kiln bring about the same effect
+as the articles of food in the ice box in that they serve to
+heat the air. Therefore, the air will be cooled by the
+lumber, causing it to pass downward through the piles.
+If the heating units are placed at the sides of the kiln,
+the action of the air in a good ice box is duplicated in the
+kiln. The significant point in this connection is that, the
+greener and colder the lumber, the faster is the circulation.
+This is a highly desirable feature.</p>
+
+<p>A second vital point is that as the wood becomes gradually
+drier the circulation automatically decreases, thus
+resulting in increased efficiency, because there is no need
+for circulation greater than enough to maintain the humidity
+of the air as it leaves the lumber about the same
+as it enters. Therefore, we advocate either the longitudinal<span class='pagenum'><a name="Page_182" id="Page_182">[182]</a></span>
+side-wise inclined pile or edge stacking, the latter
+being much preferable when possible. Of course the
+piles in our kiln were small and could not be weighted
+properly, so the best results as to reducing warping were
+not obtained.</p>
+
+<p><b>Preliminary Steaming.</b>&mdash;Because the fibres of the gums
+become plastic while moist and hot without causing defects,
+it is desirable to heat the air-dried lumber to about
+200 degrees Fahrenheit in saturated steam at atmospheric
+pressure in order to reduce the warping. This treatment
+also furnishes a means of heating the lumber very rapidly.
+It is probably a good way to stop the sap-staining of green
+lumber, if it is steamed while green. We have not investigated
+the other effects of steaming green gum, however,
+so we hesitate to recommend it.</p>
+
+<p>Temperatures as high as 210 degrees Fahrenheit were used
+with no apparent harm to the material. The best result
+was obtained with the temperature of 180 degrees Fahrenheit,
+after the first preliminary heating in steam to 200
+degrees Fahrenheit. Higher temperatures may be used
+with air-dried gum, however.</p>
+
+<p>The best method of humidity control proved to be to
+reduce the relative humidity of the air from 100 per cent
+(saturated steam) very carefully at first and then more
+rapidly to 30 per cent in about four days. If the change
+is too marked immediately after the steaming period,
+checking will invariably result. Under these temperature
+and humidity conditions the stock was dried from 15
+per cent moisture, based on the dry wood weight, to 6 per
+cent in five days' time. The loss due to checking was
+about 5 per cent, based on the actual footage loss, not on
+commercial grades.</p>
+
+<p><b>Final Steaming.</b>&mdash;From time to time during the test
+runs the material was resawed to test for case-hardening.
+The stock dried in five days showed slight case-hardening,
+so it was steamed at atmospheric pressure for 36 minutes
+near the close of the run, with the result that when dried
+off again the stresses were no longer present. The material
+from one run was steamed for three hours at atmospheric<span class='pagenum'><a name="Page_183" id="Page_183">[183]</a></span>
+pressure and proved very badly case-hardened, but
+in the reverse direction. It seems possible that by testing
+for the amount of case-hardening one might select
+a final steaming period which would eliminate all stresses
+in the wood.</p>
+
+
+<h4>Kiln-drying of Green Red Gum</h4>
+
+<p>The following article was published by the United
+States Forestry Service on the kiln-drying of green red
+gum:</p>
+
+<p>A short time ago fifteen fine, red-gum logs 16 feet long
+were received from Sardis, Miss. They were in excellent
+condition and quite green.</p>
+
+<p>It has been our belief that if the gum could be kiln-dried
+directly from the saw, a number of the difficulties
+in seasoning might be avoided. Therefore, we have undertaken
+to find out whether or not such a thing is feasible.
+The green logs now at the laboratory are to be used in
+this investigation. One run of a preliminary nature has
+just been made, the method and results of which I will
+now tell.</p>
+
+<p>This method was really adapted to the drying of Southern
+pine, and one log of the green gum was cut into 1-inch
+stock and dried with the pine. The heartwood contained
+many knots and some checks, although it was in general
+of quite good quality. The sapwood was in fine condition
+and almost as white as snow.</p>
+
+<p>This material was edge-stacked with one crosser at
+either end and one at the center, of the 16-foot board.
+This is sufficient for the pine, but was absolutely inadequate
+for drying green gum. A special shrinkage take-up was
+applied at the three points. The results proved very
+interesting in spite of the warping which was expected
+with but three crossers in 16 feet. The method of circulation
+described was used. It is our belief that edge
+piling is best for this method.</p>
+
+<p>This method of kiln-drying depends on the maintenance
+of a high velocity of slightly superheated steam through
+the lumber. In few words, the object is to maintain the
+temperature of the vapor as it leaves the lumber at slightly<span class='pagenum'><a name="Page_184" id="Page_184">[184]</a></span>
+above 212 degrees Fahrenheit. In order to accomplish this
+result, it is necessary to maintain the high velocity of
+circulation. As the wood dries, the superheat may be
+increased until a temperature of 225 degrees or 230 degrees
+Fahrenheit of the exit air is recorded.</p>
+
+<p>The 1-inch green gum was dried from 20.1 per cent to
+11.4 per cent moisture, based on the dry wood weight in
+45 hours. The loss due to checking was 10 per cent.
+Nearly every knot in the heartwood was checked, showing
+that as the knots could be eliminated in any case, this
+loss might not be so great. It was significant that practically
+all of the checking occurred in the heartwood. The
+loss due to warping was 22 per cent. Of course this was
+large; but not nearly enough crossers were used for the
+gum. It is our opinion that this loss due to warping can
+be very much reduced by using at least eight crossers and
+providing for taking up of the shrinkage. A feature of
+this process which is very important is that the method
+absolutely prevents all sap staining.</p>
+
+<p>Another delightful surprise was the manner in which
+the superheated steam method of drying changed the
+color of the sapwood from pure white to a beautifully
+uniform, clean-looking, cherry red color which very closely
+resembles that of the heartwood. This method is not
+new by any means, as several patents have been granted
+on the steaming of gum to render the sapwood more nearly
+the color of the heartwoods. The method of application
+in kiln-drying green gum we believe to be new, however.
+Other methods for kiln-drying this green stock are to be
+tested until the proper process is developed. We expect
+to have something interesting to report in the near
+future.<a name="FNanchor_1_1" id="FNanchor_1_1"></a><a href="#Footnote_1_1" class="fnanchor">[1]</a></p>
+
+<div class="footnote"><p><a name="Footnote_1_1" id="Footnote_1_1"></a><a href="#FNanchor_1_1"><span class="label">[1]</span></a> The above test was made at the United States Forestry Service Laboratory,
+Madison, Wis.</p></div>
+
+
+
+<h3 style="padding-bottom: 0em"><a name="SECTION_XII" id="SECTION_XII"></a>SECTION XII<span class='pagenum'><a name="Page_185" id="Page_185">[185]</a></span></h3>
+
+<h2>TYPES OF DRY KILNS</h2>
+
+
+<h3 style="padding-top: 0em">DIFFERENT TYPES OF DRY KILNS</h3>
+
+<p><span class="smcap">Dry</span> kilns as in use to-day are divided into two classes:
+The "pipe" or "moist-air" kiln, in which natural draft
+is relied upon for circulation and, the "blower" or "hot
+blast" kiln, in which the circulation is produced by fans
+or blowers. Both classes have their adherents and either
+one will produce satisfactory results if properly operated.</p>
+
+
+<h4>The "Blower" or "Hot Blast" Kiln</h4>
+
+<p>The blower kiln in its various types has been in use so
+long that it is hardly necessary to give to it a lengthy introduction.
+These kilns at their inauguration were a
+wonderful improvement over the old style "bake-oven"
+or "sweat box" kiln then employed, both on account of
+the improved quality of the material and the rapidity at
+which it was dried.</p>
+
+<p>These blower kilns have undergone steady improvement,
+not only in the apparatus and equipment, but also in their
+general design, method of introducing air, and provision
+for controlling the temperature and humidity. With this
+type of kiln the circulation is always under absolute control
+and can be adjusted to suit the conditions, which
+necessarily vary with the conditions of the material to
+be dried and the quantity to be put through the kiln.</p>
+
+<p>In either the blower or moist-air type of dry kiln, however,
+it is absolutely essential, in order to secure satisfactory
+results, both as to rapidity in drying and good
+quality of stock, that the kiln be so designed that the
+temperature and humidity, together with circulation, are
+always under convenient control. Any dry kiln in which
+this has not been carefully considered will not give the
+desired results.<span class='pagenum'><a name="Page_186" id="Page_186">[186]</a></span></p>
+
+<p>In the old style blower kiln, while the circulation and
+temperature was very largely under the operator's control,
+it was next to impossible to produce conditions in
+the receiving end of the kiln so that the humidity could
+be kept at the proper point. In fact, this was one reason
+why the natural draft, or so-called moist-air kiln was
+developed.</p>
+
+<p>The advent of the moist-air kiln served as an education
+to kiln designers and manufacturers, in that it has shown
+conclusively the value of a proper degree of humidity in
+the receiving end of any progressive dry kiln, and it has
+been of special benefit also in that it gave the manufacturers
+of blower kilns an idea as to how to improve the design
+of their type of kiln to overcome the difficulty referred to
+in the old style blower kilns. This has now been remedied,
+and in a decidedly simple manner, as is usually the case
+with all things that possess merit.</p>
+
+<p>It was found that by returning from one third to one
+half of the moist air <i>after</i> having passed through the kiln
+back to the fan room and by mixing it with the fresh and
+more or less dry air going into the drying room, that the
+humidity could be kept under convenient control.</p>
+
+<p>The amount of air that can be returned from a kiln of
+this class depends upon three things: (1) The condition
+of the material when entering the drying room; (2) the
+rapidity with which the material is to be dried; and (3) the
+condition of the outside atmosphere. In the winter season
+it will be found that a larger proportion of air may be
+returned to the drying room than in summer, as the air
+during the winter season contains considerably less moisture
+and as a consequence is much drier. This is rather a
+fortunate coincidence, as, when the kiln is being operated
+in this manner, it will be much more economical in its
+steam consumption.</p>
+
+<p>In the summer season, when the outside atmosphere is
+saturated to a much greater extent, it will be found that
+it is not possible to return as great a quantity of air to the
+drying room, although there have been instances of kilns
+of this class, which in operation have had all the air returned
+and found to give satisfactory results. This is<span class='pagenum'><a name="Page_187" id="Page_187">[187]</a></span>
+an unusual condition, however, and can only be accounted
+for by some special or peculiar condition surrounding the
+installation.</p>
+
+<p>In some instances, the desired amount of humidity in a
+blower type of kiln is obtained by the addition of a steam
+spray in the receiving end of the kiln, much in the same
+manner as that used in the moist-air kilns. This method
+is not as economical as returning the moisture-laden air
+from the drying room as explained in the preceding paragraph.</p>
+
+<p>With the positive circulation that may be obtained in
+a blower kiln, and with the conditions of temperature and
+humidity under convenient control, this type of kiln has
+the elements most necessary to produce satisfactory drying
+in the quickest possible elapsed time.</p>
+
+<p>It must not be inferred from this, however, that this
+class of dry kiln may be installed and satisfactory results
+obtained regardless of how it is handled. A great
+deal of the success of any dry kiln&mdash;or any other
+apparatus, for that matter&mdash;depends upon intelligent
+operation.</p>
+
+
+<h4>Operation of the "Blower" Dry Kiln</h4>
+
+<p>It is essential that the operator be supplied with proper
+facilities to keep a record of the material as it is placed
+into the drying room, and when it is taken out. An accurate
+record should be kept of the temperature every
+two or three hours, for the different thicknesses and species
+of lumber, that he may have some reliable data to guide
+him in future cases.</p>
+
+<p>Any man possessing ordinary intelligence can operate
+dry kilns and secure satisfactory results, providing he will
+use good judgment and follow the basic instructions as
+outlined below:</p>
+
+<div class="blockquot"><p>1. When cold and before putting into operation, heat
+the apparatus slowly until all pipes are hot, then
+start the fan or blower, gradually bringing it up
+to its required speed.</p>
+
+<p>2. See that <i>all</i> steam supply valves are kept wide open,<span class='pagenum'><a name="Page_188" id="Page_188">[188]</a></span>
+unless you desire to lengthen the time required to
+dry the material.</p>
+
+<p>3. When using exhaust steam, the valve from the
+header (which is a separate drip, independent of
+the trap connection) must be kept wide open, but
+must be closed when live steam is used on that
+part of the heater.</p>
+
+<p>4. The engines as supplied by the manufacturers are
+constructed to operate the fan or blower at a proper
+speed with its throttle valve wide open, and with
+not less than 80 pounds pressure of steam.</p>
+
+<p>5. If the return steam trap does not discharge regularly,
+it is important that it be opened and thoroughly
+cleaned and the valve seat re-ground.</p>
+
+<p>6. As good air circulation is as essential as the proper
+degree of heat, and as the volume of air and its
+contact with the material to be dried depends upon
+the volume delivered by the fan or blower, it is
+necessary to maintain a regular and uniform speed
+of the engine.</p>
+
+<p>7. Atmospheric openings must always be maintained
+in the fan or heater room for fresh air supply.</p>
+
+<p>8. Successful drying cannot be accomplished without
+ample and free circulation of air at all times.</p></div>
+
+<p>If the above instructions are fully carried out, and good
+judgment used in the handling and operation of the
+blower kiln, no difficulties should be encountered in successfully
+drying the materials at hand.</p>
+
+
+<h4>The "Pipe" or "Moist-air" Dry Kiln</h4>
+
+<p>While in the blower class of dry kiln, the circulation is
+obtained by forced draft with the aid of fans or blowers,
+in the Moist-air kilns (see <a href="#Fig_31">Fig. 31</a>); the circulation is obtained
+by natural draft only, aided by the manipulation
+of dampers installed at the receiving end of the drying
+room, which lead to vertical flues through a stack to the
+outside atmosphere.</p>
+
+<p>The heat in these kilns is obtained by condensing steam
+in coils of pipe, which are placed underneath the material<span class='pagenum'><a name="Page_189" id="Page_189">[189]</a></span>
+to be dried. As the degree of heat required, and steam
+pressure govern the amount of radiation, there are several
+types of radiating coils. In <a href="#Fig_32">Fig. 32</a> will be seen the Single
+Row Heating Coils for live or high pressure steam, which
+are used when the low temperature is required. <a href="#Fig_33">Figure 33</a>
+shows the Double (or 2) Row Heating Coils for live or
+high pressure steam. This apparatus is used when a
+medium temperature is required. In <a href="#Fig_34">Fig. 34</a> will be seen
+the Vertical Type Heating Coils which is recommended
+where exhaust or low-pressure steam is to be used, or may
+be used with live or high-pressure steam when high temperatures
+are desired.</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_31" id="Fig_31"></a></p>
+<img src="images/fig31.jpg" width="500" height="299" alt="Section through a typical Moist-air Dry Kiln" title="Section through a typical Moist-air Dry Kiln" />
+
+<p class="caption" style="text-align: center">Fig. 31. Section through a typical Moist-air Dry Kiln.</p>
+</div>
+
+<p>These heating coils are usually installed in sections,
+which permit any degree of heat from the minimum to
+the maximum to be maintained by the elimination of,
+or the addition of, any number of heating sections. This
+gives a dry kiln for the drying of green softwoods, or by
+shutting off a portion of the radiating coils&mdash;thus reducing
+the temperature&mdash;a dry kiln for drying hardwoods,
+that will not stand the maximum degree of heat.</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_32" id="Fig_32"></a></p>
+<img src="images/fig32.jpg" width="500" height="229" alt="Single Pipe Heating Apparatus for Dry Kilns" title="Single Pipe Heating Apparatus for Dry Kilns" />
+
+<p class="caption">Fig. 32. Single Pipe Heating Apparatus for Dry Kilns, arranged for the Use of Live Steam. For Low Temperatures.<span class='pagenum'><a name="Page_190" id="Page_190">[190]</a></span></p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_33" id="Fig_33"></a></p>
+<img src="images/fig33.jpg" width="500" height="225" alt="Double Pipe Heating Apparatus for Dry Kilns" title="Double Pipe Heating Apparatus for Dry Kilns" />
+
+<p class="caption">Fig. 33. Double Pipe Heating Apparatus for Dry Kilns, arranged for the Use of Live Steam. For Medium Temperatures.<span class='pagenum'><a name="Page_191" id="Page_191">[191]</a></span></p>
+</div>
+
+<p>In the Moist-air or Natural Draft type of dry kiln, any<span class='pagenum'><a name="Page_192" id="Page_192">[192]</a></span>
+degree of humidity, from clear and dry to a dense fog may
+be obtained; this is in fact, the main and most important
+feature of this type of dry kiln, and the most essential
+one in the drying of hardwoods.</p>
+
+<p>It is not generally understood that the length of a kiln
+has any effect upon the quantity of material that may be
+put through it, but it is a fact nevertheless that long kilns
+are much more effective, and produce a better quality of
+stock in less time than kilns of shorter length.</p>
+
+<p>Experience has proven that a kiln from 80 to 125 feet
+in length will produce the best results, and it should be
+the practice, where possible, to keep them within these
+figures. The reason for this is that in a long kiln there is
+a greater drop in temperature between the discharge end
+and the green or receiving end of the kiln.</p>
+
+<p>It is very essential that the conditions in the receiving
+end of the kiln, as far as the temperature and humidity
+are concerned, must go hand in hand.</p>
+
+<p>It has also been found that in a long kiln the desired
+conditions may be obtained with higher temperatures
+than with a shorter kiln; consequently higher temperatures
+may be carried in the discharge end of the kiln,
+thereby securing greater rapidity in drying. It is not
+unusual to find that a temperature of 200 degrees Fahrenheit
+is carried in the discharge end of a long dry kiln with
+safety, without in any way injuring the quality of the
+material, although, it would be better not to exceed 180
+degrees in the discharge end, and about 120 degrees in
+the receiving or green end in order to be on the safe side.</p>
+
+
+<h4>Operation of the "Moist-air" Dry Kiln</h4>
+
+<p>To obtain the best results these kilns should be kept
+in continuous operation when once started, that is, they
+should be operated continuously day and night. When
+not in operation at night or on Sundays, and the kiln is
+used to season green stock direct from the saw, the large
+doors at both ends of the kiln should be opened wide, or
+the material to be dried will "sap stain."</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_34" id="Fig_34"></a></p>
+<img src="images/fig34.jpg" width="500" height="168" alt="Vertical Pipe Heating Apparatus for Dry Kilns" title="Vertical Pipe Heating Apparatus for Dry Kilns" />
+
+<p class="caption">Fig. 34. Vertical Pipe Heating Apparatus for Dry Kilns; may be used in Connection with either
+Live or Exhaust Steam for High or Low Temperatures.</p>
+</div>
+
+<p>It is highly important that the operator attending any
+drying apparatus keep a minute and accurate record of<span class='pagenum'><a name="Page_193" id="Page_193">[193]</a></span>
+the condition of the material as it is placed into the drying
+room, and its final condition when taken out.</p>
+
+<p>Records of the temperature and humidity should be
+taken frequently and at stated periods for the different
+thicknesses and species of material, in order that he may
+have reliable data to guide him in future operations.<span class='pagenum'><a name="Page_194" id="Page_194">[194]</a></span></p>
+
+<p>The following facts should be taken into consideration
+when operating the Moist-air dry kiln:</p>
+
+<div class="blockquot"><p>1. Before any material has been placed in the drying
+room, the steam should be turned into the heating
+or radiating coils, gradually warming them, and
+bringing the temperature in the kiln up to the
+desired degree.</p>
+
+<p>2. Care should be exercised that there is sufficient
+humidity in the receiving or loading end of the
+kiln, in order to guard against checking, case-hardening,
+etc. Therefore it is essential that the
+steam spray at the receiving or loading end of the
+kiln be properly manipulated.</p>
+
+<p>3. As the temperature depends principally upon the
+pressure of steam carried in the boilers, maintain
+a steam pressure of not less than 80 pounds at all
+times; it may range as high as 100 pounds. The
+higher the temperature with its relatively high
+humidity the more rapidly the drying will be accomplished.</p>
+
+<p>4. Since air circulation is as essential as the proper degree
+of heat, and as its contact with the material to be
+dried depends upon its free circulation, it is necessary
+that the dampers for its admittance into,
+and its exit from, the drying room be efficiently
+and properly operated. Successful drying cannot
+be accomplished without ample and free circulation
+of air at all times during the drying process.</p></div>
+
+<p>If the above basic principles are carefully noted and
+followed out, and good common sense used in the handling
+and operation of the kiln apparatus, no serious difficulties
+should arise against the successful drying of the materials
+at hand.<span class='pagenum'><a name="Page_195" id="Page_195">[195]</a></span></p>
+
+
+<h4>Choice of Drying Method</h4>
+
+<p>At this point naturally arises the question: Which of
+the two classes of dry kilns, the "Moist-air" or "Blower"
+kiln is the better adapted for my particular needs?</p>
+
+<p>This must be determined entirely by the species of
+wood to be dried, its condition when it goes into the kiln,
+and what kind of finished product is to be manufactured
+from it.</p>
+
+<p>Almost any species of hardwood which has been subjected
+to air-seasoning for three months or more may be
+dried rapidly and in the best possible condition for glue-jointing
+and fine finishing with a "Blower" kiln, but green
+hardwood, direct from the saw, can only be successfully
+dried (if at all) in a "Moist-air" kiln.</p>
+
+<p>Most furniture factories have considerable bent stock
+which must of necessity be thoroughly steamed before
+bending. By steaming, the initial process of the Moist-air
+kiln has been consummated. Hence, the Blower kiln is
+better adapted to the drying of such stock than the Moist-air
+kiln would be, as the stock has been thoroughly soaked
+by the preliminary steaming, and all that is required is
+sufficient heat to volatilize the moisture, and a strong
+circulation of air to remove it as it comes to the surface.</p>
+
+<p>The Moist-air kiln is better adapted to the drying of
+tight cooperage stock, while the Blower kiln is almost
+universally used throughout the slack cooperage industry
+for the drying of its products.</p>
+
+<p>For the drying of heavy timbers, planks, blocks, carriage
+stock, etc., and for all species of hardwood thicker
+than one inch, the Moist-air kiln is undoubtedly the
+best.</p>
+
+<p>Both types of kilns are equally well adapted to the drying
+of 1-inch green Norway and white pine, elm, hemlock,
+and such woods as are used in the manufacture of flooring,
+ceiling, siding, shingles, hoops, tub and pail stock, etc.</p>
+
+<p>The selection of one or the other for such work is largely
+matter of personal opinion.<span class='pagenum'><a name="Page_196" id="Page_196">[196]</a></span></p>
+
+
+<h4>Kilns of Different Types</h4>
+
+<p>All dry kilns as in use to-day are divided as to method
+of drying into two classes:</p>
+
+<ul style="padding-left: 10%; line-height: 130%">
+<li>The "Pipe" or "Moist-air" kiln;</li>
+<li>The "Blower" or "Hot Blast" kiln;</li>
+</ul>
+
+
+<p>both of which have been fully explained in a previous
+article.</p>
+
+<p>The above two classes are again subdivided into five
+different types of dry kilns as follows:</p>
+
+<ul style="padding-left: 10%; line-height: 130%">
+<li>The "Progressive" kiln;</li>
+<li>The "Apartment" kiln;</li>
+<li>The "Pocket" kiln;</li>
+<li>The "Tower" kiln;</li>
+<li>The "Box" kiln.</li>
+</ul>
+
+
+
+<h4>The "Progressive" Dry Kiln</h4>
+
+<p>Dry kilns constructed so that the material goes in at
+one end and is taken out at the opposite end are called
+Progressive dry kilns, from the fact that the material
+gradually progresses through the kiln from one stage to
+another while drying (see <a href="#Fig_31">Fig. 31</a>).</p>
+
+<p>In the operation of the Progressive kiln, the material
+is first subjected to a sweating or steaming process at the
+receiving or loading end of the kiln with a low temperature
+and a relative high humidity. It then gradually progresses
+through the kiln into higher temperatures and
+lower humidities, as well as changes of air circulation,
+until it reaches the final stage at the discharge end of the
+kiln.</p>
+
+<p>Progressive kilns, in order to produce the most satisfactory
+results, especially in the drying of hardwoods or
+heavy softwood timbers, should be not less than 100 feet
+in length (see <a href="#Fig_35">Fig. 35</a>).</p>
+
+<p>In placing this type of kiln in operation, the following
+instructions should be carefully followed:</p>
+
+<p>When steam has been turned into the heating coils, and
+the kiln is fairly warm, place the first car of material to
+be dried in the drying room&mdash;preferably in the morning&mdash;about<span class='pagenum'><a name="Page_197" id="Page_197">[197]</a></span>
+25 feet from the kiln door on the receiving
+or loading end of the kiln, blocking the wheels so that it
+will remain stationary.</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_35" id="Fig_35"></a></p>
+<img src="images/fig35.jpg" width="500" height="190" alt="Exterior View of Four Progressive Dry Kilns" title="Exterior View of Four Progressive Dry Kilns" />
+
+<p class="caption">Fig. 35. Exterior View of Four Progressive Dry Kilns, each 140 Feet long by 18 Feet wide.
+Cross-wise piling, fire-proof construction.</p>
+</div>
+
+<p>Five hours later, or
+about noon, run in the
+second car and stop it
+about five feet from the
+first one placed in the
+drying room. Five
+hours later, or in the
+evening push car number
+two up against the
+first car; then run in
+car number three, stopping
+it about five feet
+from car number two.</p>
+
+<p>On the morning of
+the second day, push
+car number three
+against the others, and
+then move them all
+forward about 25 feet,
+and then run in car
+number four, stopping
+it about five feet from
+the car in advance of
+it. Five hours later, or
+about noon, run in car
+number five and stop
+it about five feet from
+car number four. In
+the evening or about
+five hours later, push
+these cars against the
+ones ahead, and run in
+loaded car number six, stopping it about five feet from the
+preceding car.</p>
+
+<p>On the morning of the third day, move all the cars forward
+about six feet; then run in loaded car number seven
+stop it about four feet from the car preceding it.<span class='pagenum'><a name="Page_198" id="Page_198">[198]</a></span>
+Five hours later or about noon push this car against those
+in advance of it, and run in loaded car number eight
+moving all cars forward about six feet, and continue in
+this manner until the full complement of cars have been
+placed in the kiln. When the kiln has been filled, remove
+car number one and push all the remaining cars
+forward and run in the next loaded car, and continue in
+this manner as long as the kiln is in operation.</p>
+
+<p>As the temperature depends principally upon the pressure
+of steam, maintain a steam pressure of not less than
+80 pounds at all times; it may range up to as high as 100
+pounds. The higher the temperature with a relatively
+higher humidity the more rapidly the drying will be accomplished.</p>
+
+<p>If the above instructions are carried out, the temperatures,
+humidities, and air circulation properly manipulated,
+there should be complete success in the handling
+of this type of dry kiln.</p>
+
+<p>The Progressive type of dry kiln is adapted to such lines
+of manufacture that have large quantities of material to
+kiln-dry where the species to be dried is of a similiar
+nature or texture, and does not vary to any great extent
+in its thickness, such, for instance, as:</p>
+
+<ul style="padding-left: 10%; line-height: 130%">
+<li>Oak flooring plants;</li>
+<li>Maple flooring plants;</li>
+<li>Cooperage plants;</li>
+<li>Large box plants;</li>
+<li>Furniture factories; etc.</li>
+</ul>
+
+
+<p>In the selection of this kind of dry kiln, consideration
+should be given to the question of ground space of sufficient
+length or dimension to accommodate a kiln of proper length
+for successful drying.</p>
+
+
+<h4>The "Apartment" Dry Kiln</h4>
+
+<p>The Apartment system of dry kilns are primarily designed
+for the drying of different kinds or sizes of material
+at the same time, a separate room or apartment being
+devoted to each species or size when the quantity is sufficient
+(see <a href="#Fig_36">Fig. 36</a>).<span class='pagenum'><a name="Page_199" id="Page_199">[199]</a></span></p>
+
+<p>These kilns are sometimes built single or in batteries
+of two or more, generally not exceeding 40 or 50 feet
+in length with doors and platforms at both ends the same
+as the Progressive kilns; but in operation each kiln is
+entirely filled at one loading and then closed, and the
+entire contents dried at one time, then emptied and again
+recharged.</p>
+
+<p>Any number of apartments may be built, and each
+apartment may be arranged to handle any number of cars,
+generally about three or four, or they may be so constructed
+that the material is piled directly upon the floor
+of the drying room.</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_36" id="Fig_36"></a></p>
+<img src="images/fig36.jpg" width="500" height="288" alt="Exterior View of Six Apartment Dry Kilns" title="Exterior View of Six Apartment Dry Kilns" />
+
+<p class="caption">Fig. 36. Exterior View of Six Apartment Dry Kilns, each 10 Feet wide by
+52 Feet long, End-wise Piling. They are entirely of fire-proof construction
+and equipped with double doors (Hussey asbestos outside and
+canvas inside), and are also equipped with humidity and air control
+dampers, which may be operated from the outside without opening
+the kiln doors, which is a very good feature.</p>
+</div>
+
+<p>When cars are used, it is well to have a transfer car at
+each end of the kilns, and stub tracks for holding cars of
+dry material, and for the loading of the unseasoned stock,
+as in this manner the kilns may be kept in full operation
+at all times.</p>
+
+<p>In this type of dry kiln the material receives the same<span class='pagenum'><a name="Page_200" id="Page_200">[200]</a></span>
+treatment and process that it would in a Progressive kiln.
+The advantages of Apartment kilns is manifest where
+certain conditions require the drying of numerous kinds
+as well as thicknesses of material at one and the same time.
+This method permits of several short drying rooms or
+apartments so that it is not necessary to mix hardwoods
+and softwoods, or thick and thin material in the same kiln
+room.</p>
+
+<p>In these small kilns the circulation is under perfect
+control, so that the efficiency is equal to that of the more
+extensive plants, and will readily appeal to manufacturers
+whose output calls for the prompt and constant seasoning
+of a large variety of small stock, rather than a large volume
+of material of uniform size and grade.</p>
+
+<p>Apartment kilns are recommended for industries where
+conditions require numerous kinds and thicknesses of
+material to be dried, such as:</p>
+
+<ul style="padding-left: 10%; line-height: 130%">
+<li>Furniture factories;</li>
+<li>Piano factories;</li>
+<li>Interior woodwork mills;</li>
+<li>Planing mills; etc.</li>
+</ul>
+
+
+
+<h4>The "Pocket" Dry Kiln</h4>
+
+<p>"Pocket" dry kilns (see <a href="#Fig_37">Fig. 37</a>) are generally built in
+batteries of several pockets. They have the tracks level
+and the lumber goes in and out at the same end. Each
+drying room is entirely filled at one time, the material is
+dried and then removed and the kiln again recharged.</p>
+
+<p>The length of "Pocket" kilns ranges generally from
+14 feet to about 32 feet.</p>
+
+<p>The interior equipment for this type of dry kiln is
+arranged very similiar to that used in the Apartment
+kiln. The heating or radiating coils and steam spray
+jets extend the whole length of the drying room, and are
+arranged for the use of either live or exhaust steam, as
+desired.</p>
+
+<p>Inasmuch as Pocket kilns have doors at one end only,
+this feature eliminates a certain amount of door exposure,
+which conduces towards economy in operation.<span class='pagenum'><a name="Page_201" id="Page_201">[201]</a></span></p>
+
+<p>In operating Pocket kilns, woods of different texture
+and thickness should be separated and placed in different
+drying rooms, and each kiln adjusted and operated
+to accommodate the peculiarities of the species and thickness
+of the material to be dried.</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_37" id="Fig_37"></a></p>
+<img src="images/fig37.jpg" width="500" height="350" alt="Exterior View of Five Pocket Dry Kilns" title="Exterior View of Five Pocket Dry Kilns" />
+
+<p class="caption">Fig. 37. Exterior View of Five Pocket Dry Kilns, built in Two Batteries with the Front of each Set facing
+the other, and a Transfer System between. They are also equipped with the asbestos doors.</p>
+</div>
+
+<p>Naturally, the more complex the conditions of manufacturing
+wood products in any industry, the more difficult<span class='pagenum'><a name="Page_202" id="Page_202">[202]</a></span>
+will be the proper drying of same. Pocket kilns,
+are, therefore, recommended for factories having several
+different kinds and thicknesses of material to dry in small
+quantities of each, such as:</p>
+
+<ul style="padding-left: 10%; line-height: 130%">
+<li>Planing mills;</li>
+<li>Chair factories;</li>
+<li>Furniture factories;</li>
+<li>Sash and door factories; etc.</li>
+</ul>
+
+
+
+<h4>The "Tower" Dry Kiln</h4>
+
+<p>The so-called "Tower" dry kiln (see <a href="#Fig_38">Fig. 38</a>) is designed
+for the rapid drying of small stuff in quantities.
+Although the general form of construction and the capacity
+of the individual bins or drying rooms may vary, the same
+essential method of operation is common to all. That is,
+the material itself, such as wooden novelties, loose staves,
+and heading for tubs, kits, and pails, for box stuff, kindling
+wood, etc., is dumped directly into the drying rooms
+from above, or through the roof, in such quantities as
+effectually to fill the bin, from which it is finally removed
+when dry, through the doors at the bottom.</p>
+
+<p>These dry kilns are usually operated as "Blower" kilns,
+the heating apparatus is generally located in a separate
+room or building adjacent to the main structure or drying
+rooms, and arranged so that the hot air discharged through
+the inlet duct (see illustration) is thoroughly distributed
+beneath a lattice floor upon which rests the material to
+be dried. Through this floor the air passes directly upward,
+between and around the stock, and finally returns
+to the fan or heating room.</p>
+
+<p>This return air duct is so arranged that by means of
+dampers, leading from each drying room, the air may be
+returned in any quantity to the fan room where it is mixed
+with fresh air and again used. This is one of the main
+features of economy of the blower system of drying, as
+by the employment of this return air system, considerable
+saving may be made in the amount of steam required for
+drying.</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_38" id="Fig_38"></a></p>
+<img src="images/fig38.jpg" width="500" height="275" alt="Exterior and Sectional View of a Battery of Tower Dry Kilns" title="Exterior and Sectional View of a Battery of Tower Dry Kilns" />
+
+<p class="caption">Fig. 38. Exterior and Sectional View of a Battery of Tower Dry Kilns. This is a "Blower" or "Hot Blast" type, and
+shows the arrangement of the fan blower, engine, etc. This type of dry kin is used principally for the seasoning of
+small, loose material.</p>
+</div>
+
+<p>The lattice floors in this type of dry kiln are built on<span class='pagenum'><a name="Page_203" id="Page_203">[203]</a></span>
+an incline, which arrangement materially lessens the cost,
+and increases the convenience with which the dried stock
+may be removed from the bins or drying rooms.</p>
+
+<p>In operation, the material is conveyed in cars or trucks<span class='pagenum'><a name="Page_204" id="Page_204">[204]</a></span>
+on an overhead trestle&mdash;which is inclosed&mdash;from which
+the material to be dried is dumped directly into the drying
+rooms or bins, through hoppers arranged for that purpose
+thereby creating considerable saving in the handling of
+the material to be dried into the kiln. The entire arrangement
+thus secures the maximum capacity, with a
+minimum amount of floor space, with the least expense.
+Of course, the higher these kilns are built, the less relative
+cost for a given result in the amount of material dried.</p>
+
+<p>In some instances, these kilns are built less in height
+and up against an embankment so that teamloads of
+material may be run directly onto the roof of the kilns, and
+dumped through the hoppers into the drying rooms or
+bins, thus again reducing to a minimum the cost of
+this handling.</p>
+
+<p>The return air duct plays an important part in both of
+these methods of filling, permitting the air to become
+saturated to the maximum desired, and utilizing much
+of the heat contained therein, which would otherwise
+escape to the atmosphere.</p>
+
+<p>The "Tower" kiln is especially adapted to factories
+of the following class:</p>
+
+<ul style="padding-left: 10%; line-height: 130%">
+<li>Sawmills;</li>
+<li>Novelty factories;</li>
+<li>Woodenware factories;</li>
+<li>Tub and pail factories; etc.</li>
+</ul>
+
+
+
+<h4>The "Box" Dry Kiln</h4>
+
+<p>The "Box" kiln shown in <a href="#Fig_39">Figure 39</a> is an exterior view
+of a kiln of this type which is 20 feet wide, 19 feet deep,
+and 14 feet high, which is the size generally used when
+the space will permit.</p>
+
+<p>Box kilns are used mostly where only a small quantity
+of material is to be dried. They are not equipped with
+trucks or cars, the material to be dried being piled upon a<span class='pagenum'><a name="Page_205" id="Page_205">[205]</a></span>
+raised platform inside the drying room. This arrangement,
+therefore, makes them of less cost than the other
+types of dry kilns.</p>
+
+<p>They are particularly adapted to any and all species
+and size of lumber to be dried in very small quantities.</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_39" id="Fig_39"></a></p>
+<img src="images/fig39.jpg" width="500" height="332" alt="Exterior view of the Box Dry Kiln" title="Exterior view of the Box Dry Kiln" />
+
+<p class="caption">Fig. 39. Exterior view of the Box Dry Kiln. This particular kiln is 20 feet
+wide, 19 feet deep and 14 feet high. Box kilns are used mostly where
+only a small amount of kiln-dried lumber of various sizes is required.
+They are not equipped with trucks or cars, and therefore cost less to
+construct than any other type of dry kiln.</p>
+</div>
+
+<p>In these small kilns the circulation is under perfect
+control, so that the efficiency is equal to that of the more
+extensive plants.</p>
+
+<p>These special kilns will readily appeal to manufacturers,
+whose output calls for the prompt and constant seasoning
+of a large variety of small stock, rather than a large volume
+material of uniform size and grade.</p>
+
+
+
+<h3 style="padding-bottom: 0em"><a name="SECTION_XIII" id="SECTION_XIII"></a>SECTION XIII<span class='pagenum'><a name="Page_206" id="Page_206">[206]</a></span></h3>
+
+<h2>DRY KILN SPECIALTIES</h2>
+
+
+<h3 style="padding-top: 0em">KILN CARS AND METHOD OF LOADING</h3>
+
+<p><span class="smcap">Within</span> recent years, the edge-wise piling of lumber
+(see <a href="#Fig_40">Figs. 40</a> and <a href="#Fig_41">41</a>), upon kiln cars has met with considerable
+favor on account of its many advantages over
+the older method of flat piling. It has been proven that
+lumber stacked edge-wise dries more uniformly and rapidly,
+and with practically no warping or twisting of the material,
+and that it is finally discharged from the dry kiln in a
+much better and brighter condition. This method of
+piling also considerably increases the holding and consequent
+drying capacities of the dry kiln by reason of the
+increased carrying capacities of the kiln cars, and the
+shorter period of time required for drying the material.</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_40" id="Fig_40"></a></p>
+<img src="images/fig40.jpg" width="500" height="276" alt="Car Loaded with Lumber on its Edges by the Automatic Stacker" title="Car Loaded with Lumber on its Edges by the Automatic Stacker" />
+
+<p class="caption">Fig. 40. Car Loaded with Lumber on its Edges by the Automatic Stacker,
+to go into the Dry Kiln cross-wise. Equipped with two edge piling
+kiln trucks.<span class='pagenum'><a name="Page_207" id="Page_207">[207]</a></span></p>
+</div>
+
+<p>In <a href="#Fig_42">Figures 42</a> and <a href="#Fig_43">43</a> are shown different views of the
+automatic lumber stacker for edge-wise piling of lumber on
+kiln cars. Many users of automatic stackers report that
+the grade of their lumber is raised to such an extent that
+the system would be profitable for this reason alone, not
+taking into consideration the added saving in time and
+labor, which to anyone's mind should be the most important
+item.</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_41" id="Fig_41"></a></p>
+<img src="images/fig41.jpg" width="500" height="244" alt=" Car Loaded with Lumber on its Edges by the Automatic Stacker" title=" Car Loaded with Lumber on its Edges by the Automatic Stacker" />
+
+<p class="caption">Fig. 41. Car Loaded with Lumber on its Edges by the Automatic Stacker,
+to go into the Dry Kiln end-wise. The bunks on which the lumber
+rests are channel steel. The end sockets are malleable iron and made
+for I-beam stakes.</p>
+</div>
+
+<p>In operation, the lumber is carried to these automatic
+stackers on transfer chains or chain conveyors, and passes
+on to the stacker table. When the table is covered with
+boards, the "lumber" lever is pulled by the operator,
+which raises a stop, preventing any more lumber leaving
+the chain conveyor. The "table" lever then operates
+the friction drive and raises the table filled with the boards
+to a vertical position. As the table goes up, it raises the
+latches, which fall into place behind the piling strips that
+had been previously laid on the table. When the table
+returns to the lower position, a new set of piling strips
+are put in place on the table, and the stream of boards
+which has been accumulating on the conveyor chain are
+again permitted to flow onto the table. As each layer of
+lumber is added, the kiln car is forced out against a strong<span class='pagenum'><a name="Page_208" id="Page_208">[208]</a></span>
+tension. When the car is loaded, binders are put on over
+the stakes by means of a powerful lever arrangement.</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_42" id="Fig_42"></a></p>
+<img src="images/fig42.jpg" width="500" height="335" alt="The Construction of the Automatic Lumber Stacker" title="The Construction of the Automatic Lumber Stacker" />
+
+<p class="caption">Fig. 42. The above illustration shows the construction of the Automatic
+Lumber Stacker for edge piling of lumber to go into the dry kiln end-wise.</p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_43" id="Fig_43"></a></p>
+<img src="images/fig43.jpg" width="500" height="334" alt="The Construction of the Automatic Lumber Stacker" title="The Construction of the Automatic Lumber Stacker" />
+
+<p class="caption">Fig. 43. The above illustration shows the construction of the Automatic
+Lumber Stacker for edge piling of lumber to go into the dry kiln cross-wise.<span class='pagenum'><a name="Page_209" id="Page_209">[209]</a></span></p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_44" id="Fig_44"></a></p>
+<img src="images/fig44.jpg" width="500" height="375" alt="Battery of Three Automatic Lumber
+Stackers" title="Battery of Three Automatic Lumber
+Stackers" />
+
+<p class="caption" style="text-align: center">Fig. 44. The above illustration shows a battery of Three Automatic Lumber
+Stackers.</p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_45" id="Fig_45"></a></p>
+<img src="images/fig45.jpg" width="500" height="368" alt="Another battery of Three Automatic
+Lumber Stackers" title="Another battery of Three Automatic
+Lumber Stackers" />
+
+<p class="caption">Fig. 45. The above illustration shows another battery of Three Automatic
+Lumber Stackers.<span class='pagenum'><a name="Page_210" id="Page_210">[210]</a></span></p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_46" id="Fig_46"></a></p>
+<img src="images/fig46.jpg" width="500" height="402" alt="Cars Loaded with Lumber on its Edges by the Automatic Lumber
+Stackers" title="Cars Loaded with Lumber on its Edges by the Automatic Lumber
+Stackers" />
+
+<p class="caption" style="text-align: center">Fig. 46. Cars Loaded with Lumber on its Edges by the Automatic Lumber
+Stackers.</p>
+</div>
+
+<p>After leaving the dry kilns, the loaded car is transferred
+to the unstacker (see <a href="#Fig_47">Fig. 47</a>). Here it is placed on the
+unstacker car which, by means of a tension device, holds
+the load of lumber tight against the vertical frame of the
+unstacker. The frame of the unstacker is triangular
+and has a series of chains. Each chain has two special
+links with projecting lugs. The chains all travel in unison.
+The lug links engage a layer of boards, sliding the entire
+layer vertically, and the boards, one at a time, fall over
+the top of the unstacker frame onto the inclined table,
+and from there onto conveyor chains from which they
+may be delivered to any point desired, depending upon
+the length and direction of the chain conveyor.</p>
+
+<p>With these unstackers one man can easily unload a
+kiln car in twenty minutes or less.</p>
+
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_47" id="Fig_47"></a></p>
+<img src="images/fig47.jpg" width="500" height="401" alt="The Lumber Unstacker Car" title="The Lumber Unstacker Car" />
+
+<p class="caption">Fig. 47. The Lumber Unstacker Car, used for unloading cars of Lumber
+loaded by the Automatic Stacker.</p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_48" id="Fig_48"></a></p>
+<img src="images/fig48.jpg" width="500" height="361" alt="The Lumber Unstacker Car and Unstacker" title="The Lumber Unstacker Car and Unstacker" />
+
+<p class="caption">Fig. 48. The Lumber Unstacker Car and Unstacker, used for unloading
+Lumber loaded by the Automatic Stacker.</p>
+</div>
+
+<p>The experience of many users prove that these edge
+stacking machines are not alike. This is important,
+because there is one feature of edge stacking that must
+not be overlooked. Unless each layer of boards is forced<span class='pagenum'><a name="Page_211" id="Page_211">[211]</a></span>
+into place by power and held under a strong pressure, much
+slack will accumulate in an entire load, and the subsequent
+handling of the kiln cars, and the effect of the kiln-drying
+will loosen up the load until there is a tendency for the
+layers to telescope. And unless the boards are held in
+place rigidly and with strong pressure they will have a
+tendency to warp.</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_49" id="Fig_49"></a></p>
+<img src="images/fig49.jpg" width="500" height="320" alt="Method of loading kiln cars" title="Method of loading kiln cars" />
+
+<p class="caption">Fig. 49. The above illustration shows method of loading kiln cars with<span class='pagenum'><a name="Page_212" id="Page_212">[212]</a></span>
+veneer on its edges by the use of the Tilting Platform.</p>
+</div>
+
+<p>A kiln car of edge-stacked lumber, properly piled, is
+made up of alternate solid sheets of lumber and vertical
+open-air spaces, so that the hot air and vapors rise naturally
+and freely through the lumber, drying both sides of the
+board evenly. The distribution of the heat and moisture
+being even and uniform, the drying process is naturally
+quickened, and there is no opportunity or tendency for
+the lumber to warp.</p>
+
+<p>In <a href="#Fig_49">Figure 49</a> will be seen a method of loading kiln cars
+with veneer on edge by the use of a tilting platform. On
+the right of the illustration is seen a partially loaded kiln
+car tilted to an angle of 45 degrees, to facilitate the placing<span class='pagenum'><a name="Page_213" id="Page_213">[213]</a></span>
+of the veneer on the car. At the left is a completely
+loaded car ready to enter the dry kiln.</p>
+
+<p>Gum, poplar, and pine veneers are satisfactorily dried
+in this manner in from 8 to 24 hours.</p>
+
+<p>In <a href="#Fig_50">Figure 50</a> will be seen method of piling lumber on
+the flat, "cross-wise" of the dry kiln when same has three
+tracks.</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_50" id="Fig_50"></a></p>
+<img src="images/fig50.jpg" width="500" height="322" alt="Method of Loading lumber" title="Method of Loading lumber" />
+
+<p class="caption">Fig. 50. Method of Loading lumber on its Flat, cross-wise of the Dry
+Kiln when same has Three Tracks.</p>
+</div>
+
+<p>In <a href="#Fig_51">Figure 51</a> will be seen another method of piling lumber
+on the flat, "cross-wise" of the dry kiln when same
+has three tracks.</p>
+
+<p>In <a href="#Fig_52">Figure 52</a> will be seen method of piling lumber on the
+flat, "end-wise" of the dry kiln when same has two tracks.</p>
+
+<p>In <a href="#Fig_53">Figure 53</a> will be seen another method of piling lumber
+on the flat, "end-wise" of the dry kiln when same has
+two tracks.</p>
+
+<p>In <a href="#Fig_54">Figure 54</a> will be seen method of piling slack or tight
+barrel staves "cross-wise" of the kiln when same has three
+tracks.</p>
+
+<p>In <a href="#Fig_55">Figure 55</a> will be seen another method of piling slack
+or tight barrel staves "cross-wise" of the dry kiln when
+same has three tracks.</p>
+
+<p>In <a href="#Fig_56">Figure 56</a> will be seen method of piling small tub or
+pail staves "cross-wise" of the dry kiln when same has
+two tracks.</p>
+
+<p>In <a href="#Fig_57">Figure 57</a> will be seen method of piling bundled staves
+"cross-wise" of the dry kiln when same has two tracks.<span class='pagenum'><a name="Page_214" id="Page_214">[214]</a></span></p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_51" id="Fig_51"></a></p>
+<img src="images/fig51.jpg" width="500" height="320" alt="Method of loading Lumber" title="Method of loading Lumber" />
+
+<p class="caption">Fig. 51. Method of loading Lumber on its Flat, cross-wise of the Dry Kiln
+when same has Three Tracks.</p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_52" id="Fig_52"></a></p>
+<img src="images/fig52.jpg" width="500" height="315" alt="Method of loading Lumber" title="Method of loading Lumber" />
+
+<p class="caption">Fig. 52. Method of loading Lumber on its Flat, end-wise of the Dry Kiln
+by the Use of the Single-sill or Dolly Truck.<span class='pagenum'><a name="Page_215" id="Page_215">[215]</a></span></p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_53" id="Fig_53"></a></p>
+<img src="images/fig53.jpg" width="500" height="275" alt="Method of loading Lumber" title="Method of loading Lumber" />
+
+<p class="caption">Fig. 53. Method of loading Lumber on its Flat, end-wise of the Dry Kiln by the Use of the
+Double-sill Truck.<span class='pagenum'><a name="Page_216" id="Page_216">[216]</a></span></p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_54" id="Fig_54"></a></p>
+<img src="images/fig54.jpg" width="500" height="341" alt=" Method of loading Kiln Car" title=" Method of loading Kiln Car" />
+
+<p class="caption">Fig. 54. Method of loading Kiln Car with Tight or Slack Barrel Staves
+cross-wise of Dry Kiln.</p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_55" id="Fig_55"></a></p>
+<img src="images/fig55.jpg" width="500" height="372" alt="Method of loading Kiln Car" title="Method of loading Kiln Car" />
+
+<p class="caption">Fig. 55. Method of loading Kiln Car with Tight or Slack Barrel Staves
+cross-wise of Dry Kiln.<span class='pagenum'><a name="Page_217" id="Page_217">[217]</a></span></p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_56" id="Fig_56"></a></p>
+<img src="images/fig56.jpg" width="500" height="453" alt="Method of loading Kiln Car" title="Method of loading Kiln Car" />
+
+<p class="caption">Fig. 56. Method of loading Kiln Car with Tub or Pail Staves cross-wise of
+Dry Kiln.</p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_57" id="Fig_57"></a></p>
+<img src="images/fig57.jpg" width="500" height="520" alt="Method of loading Kiln Car" title="Method of loading Kiln Car" />
+
+<p class="caption" style="text-align: center">Fig. 57. Method of loading Kiln Car with Bundled Staves cross-wise of
+Dry Kiln.<span class='pagenum'><a name="Page_218" id="Page_218">[218]</a></span></p>
+</div>
+
+<p>In <a href="#Fig_58">Figure 58</a> will be seen method of piling shingles "cross-wise"
+of dry kiln when same has three tracks.</p>
+
+<p>In <a href="#Fig_59">Figure 59</a> will be seen another method of piling
+shingles "cross-wise" of the dry kiln when same has three
+tracks.</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_58" id="Fig_58"></a></p>
+<img src="images/fig58.jpg" width="500" height="416" alt="Method of loading Kiln Car" title="Method of loading Kiln Car" />
+
+<p class="caption" style="text-align: center">Fig. 58. Method of loading Kiln Car with Shingles cross-wise of Dry Kiln.</p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_59" id="Fig_59"></a></p>
+<img src="images/fig59.jpg" width="500" height="328" alt="Method of loading Kiln Car" title="Method of loading Kiln Car" />
+
+<p class="caption" style="text-align: center">Fig. 59. Method of loading Kiln Car with Shingles cross-wise of Dry Kiln.<span class='pagenum'><a name="Page_219" id="Page_219">[219]</a></span></p>
+</div>
+
+<p>In <a href="#Fig_60">Figure 60</a> will be seen method of piling shingles "end-wise"
+of the dry kiln when same has two tracks.</p>
+
+<p>In <a href="#Fig_61">Figure 61</a> will be seen a kiln car designed for handling
+short tub or pail staves through a dry kiln.</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_60" id="Fig_60"></a></p>
+<img src="images/fig60.jpg" width="500" height="262" alt="Car loaded with 100,000 Shingles" title="Car loaded with 100,000 Shingles" />
+
+<p class="caption">Fig. 60. Car loaded with 100,000 Shingles. Equipped with four long end-wise
+piling trucks and to go into dry kiln end-wise.</p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_61" id="Fig_61"></a></p>
+<img src="images/fig61.jpg" width="500" height="450" alt="Kiln Car designed for handling Short Tub or Pail Staves" title="Kiln Car designed for handling Short Tub or Pail Staves" />
+
+<p class="caption" style="text-align: center">Fig. 61. Kiln Car designed for handling Short Tub or Pail Staves through
+a Dry Kiln.<span class='pagenum'><a name="Page_220" id="Page_220">[220]</a></span></p>
+</div>
+
+<p>In <a href="#Fig_62">Figure 62</a> will be seen a kiln car designed for short
+piece stock through a dry kiln.</p>
+
+<p>In <a href="#Fig_63">Figure 63</a> will be seen a type of truck designed for
+the handling of stave bolts about a stave mill or through
+a steam box.</p>
+
+<p>In <a href="#Fig_64">Figure 64</a> will be seen another type of truck designed
+for the handling of stave bolts about a stave mill or through
+a steam box.</p>
+
+<p>In <a href="#Fig_65">Figure 65</a> will be seen another type of truck designed
+for the handling of stave bolts about a stave mill or through
+a steam box.</p>
+
+<p>In <a href="#Fig_66">Figure 66</a> will be seen another type of truck designed
+for the handling of stave bolts about a stave mill or through
+a steam box.</p>
+
+<p>In <a href="#Fig_67">Figure 67</a> will be seen another type of truck designed
+for the handling of stave bolts about a stave mill or through
+a steam box.</p>
+
+<p>In <a href="#Fig_68">Figure 68</a> will be seen another type of truck designed
+for the handling of stave bolts about a stave mill or through
+a steam box.</p>
+
+<p>In <a href="#Fig_69">Figure 69</a> will be seen the Regular 3-rail Transfer
+Car designed for the handling of 2-rail kiln cars which
+have been loaded "end-wise."</p>
+
+<p>In <a href="#Fig_70">Figure 70</a> will be seen another type of Regular 3-rail
+Transfer Car designed for the handling of 2-rail kiln cars
+which have been loaded "end-wise."</p>
+
+<p>In <a href="#Fig_71">Figure 71</a> will be seen a Specially-designed 4-rail
+Transfer Car for 2-rail kiln cars which have been built
+to accommodate extra long material to be dried.</p>
+
+<p>In <a href="#Fig_72">Figure 72</a> will be seen the Regular 2-rail Transfer
+Car designed for the handling of 3-rail kiln cars which have
+been loaded "cross-wise."</p>
+
+<p>In <a href="#Fig_73">Figure 73</a> will be seen another type of Regular 2-rail
+Transfer Car designed for the handling of 3-rail kiln cars
+which have been loaded "cross-wise."</p>
+
+<p>In <a href="#Fig_74">Figure 74</a> will be seen the Regular 2-rail Underslung
+type of Transfer Car designed for the handling of 3-rail
+kiln cars which have been loaded "cross-wise." Two important
+features in the construction of this transfer car
+make it extremely easy in its operation. It has extra large
+wheels, diameter 13<span class="above">1</span>&#8260;<span class="below">2</span> inches, and being underslung, the
+top of its rails are no higher than the other types of transfer
+cars. Note the relative size of the wheels in the illustration,
+yet the car is only about 10 inches in height.<span class='pagenum'><a name="Page_221" id="Page_221">[221]</a></span></p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_62" id="Fig_62"></a></p>
+<img src="images/fig62.jpg" width="500" height="353" alt="Kiln Car Designed for handling Short Piece Stock" title="Kiln Car Designed for handling Short Piece Stock" />
+
+<p class="caption" style="text-align: center">Fig. 62. Kiln Car Designed for handling Short Piece Stock through a Dry Kiln.</p>
+</div>
+
+<div class="figcenter" style="width: 300px; padding-top: 2em"><p class="anchor"><a name="Fig_63" id="Fig_63"></a></p>
+<img src="images/fig63.jpg" width="300" height="397" alt="A Stave Bolt Truck" title="A Stave Bolt Truck" />
+
+<p class="caption" style="text-align: center">Fig. 63. A Stave Bolt Truck.<span class='pagenum'><a name="Page_222" id="Page_222">[222]</a></span></p>
+</div>
+
+<div class="figcenter" style="width: 300px; padding-top: 2em"><p class="anchor"><a name="Fig_64" id="Fig_64"></a></p>
+<img src="images/fig64.jpg" width="300" height="323" alt="A Stave Bolt Truck" title="A Stave Bolt Truck" />
+
+<p class="caption" style="text-align: center">Fig. 64. A Stave Bolt Truck.</p>
+</div>
+
+<div class="figcenter" style="width: 300px; padding-top: 2em"><p class="anchor"><a name="Fig_65" id="Fig_65"></a></p>
+<img src="images/fig65.jpg" width="300" height="379" alt="A Stave Bolt Truck" title="A Stave Bolt Truck" />
+
+<p class="caption" style="text-align: center">Fig. 65. A Stave Bolt Truck.<span class='pagenum'><a name="Page_223" id="Page_223">[223]</a></span></p>
+</div>
+
+<div class="figcenter" style="width: 300px; padding-top: 2em"><p class="anchor"><a name="Fig_66" id="Fig_66"></a></p>
+<img src="images/fig66.jpg" width="300" height="348" alt="A Stave Bolt Truck" title="A Stave Bolt Truck" />
+
+<p class="caption" style="text-align: center">Fig. 66. A Stave Bolt Truck.</p>
+</div>
+
+<div class="figcenter" style="width: 300px; padding-top: 2em"><p class="anchor"><a name="Fig_67" id="Fig_67"></a></p>
+<img src="images/fig67.jpg" width="300" height="332" alt="A Stave Bolt Truck" title="A Stave Bolt Truck" />
+
+<p class="caption" style="text-align: center">Fig. 67. A Stave Bolt Truck.<span class='pagenum'><a name="Page_224" id="Page_224">[224]</a></span></p>
+</div>
+
+<div class="figcenter" style="width: 300px; padding-top: 2em"><p class="anchor"><a name="Fig_68" id="Fig_68"></a></p>
+<img src="images/fig68.jpg" width="300" height="424" alt="A Stave Bolt Truck" title="A Stave Bolt Truck" />
+
+<p class="caption" style="text-align: center">Fig. 68. A Stave Bolt Truck.</p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_69" id="Fig_69"></a></p>
+<img src="images/fig69.jpg" width="500" height="216" alt="A Regular 3-Rail Transfer Truck" title="A Regular 3-Rail Transfer Truck" />
+
+<p class="caption" style="text-align: center">Fig. 69. A Regular 3-Rail Transfer Truck.<span class='pagenum'><a name="Page_225" id="Page_225">[225]</a></span></p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_70" id="Fig_70"></a></p>
+<img src="images/fig70.jpg" width="500" height="237" alt="A Regular 3-Rail Transfer Truck" title="A Regular 3-Rail Transfer Truck" />
+
+<p class="caption" style="text-align: center">Fig. 70. A Regular 3-Rail Transfer Truck.</p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_71" id="Fig_71"></a></p>
+<img src="images/fig71.jpg" width="500" height="186" alt="A Special 4-Rail Transfer Truck" title="A Special 4-Rail Transfer Truck" />
+
+<p class="caption" style="text-align: center">Fig. 71. A Special 4-Rail Transfer Truck.</p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_72" id="Fig_72"></a></p>
+<img src="images/fig72.jpg" width="500" height="249" alt="A Regular 2-Rail Transfer Truck" title="A Regular 2-Rail Transfer Truck" />
+
+<p class="caption" style="text-align: center">Fig. 72. A Regular 2-Rail Transfer Truck.<span class='pagenum'><a name="Page_226" id="Page_226">[226]</a></span></p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_73" id="Fig_73"></a></p>
+<img src="images/fig73.jpg" width="500" height="189" alt="A Regular 2-Rail Transfer Truck" title="A Regular 2-Rail Transfer Truck" />
+
+<p class="caption" style="text-align: center">Fig. 73. A Regular 2-Rail Transfer Truck.</p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_74" id="Fig_74"></a></p>
+<img src="images/fig74.jpg" width="500" height="165" alt="A Regular 2-Rail Underslung Transfer Truck" title="A Regular 2-Rail Underslung Transfer Truck" />
+
+<p class="caption" style="text-align: center">Fig. 74. A Regular 2-Rail Underslung Transfer Truck.</p>
+</div>
+
+
+<p>In <a href="#Fig_75">Figure 75</a> will be seen the Regular 3-rail Underslung
+type of Transfer Car designed for the handling of 2-rail
+kiln cars which have been loaded "end-wise." This car
+also has the important features of large diameter wheels
+and low rail construction, which make it very easy in its
+operation.</p>
+
+<div class="figcenter" style="width: 500px"><p class="anchor"><a name="Fig_75" id="Fig_75"></a></p>
+<img src="images/fig75.jpg" width="500" height="219" alt="A Regular 3-Rail Underslung Transfer Truck" title="A Regular 3-Rail Underslung Transfer Truck" />
+
+<p class="caption" style="text-align: center">Fig. 75. A Regular 3-Rail Underslung Transfer Truck.<span class='pagenum'><a name="Page_227" id="Page_227">[227]</a></span></p>
+</div>
+
+<p>In <a href="#Fig_76">Figure 76</a> will be seen the Special 2-rail Flexible
+type of Transfer Car designed for the handling of 3-rail
+kiln cars which have been loaded "cross-wise." This car
+is equipped with double the usual number of wheels, and
+by making each set of trucks a separate unit (the front
+and rear trucks being bolted to a steel beam with malleable
+iron connection), a slight up-and-down movement is permitted,
+which enables this transfer car to adjust itself to
+any unevenness in the track, which is a very good feature.</p>
+
+<div class="figcenter" style="width: 500px"><p class="anchor"><a name="Fig_76" id="Fig_76"></a></p>
+<img src="images/fig76.jpg" width="500" height="215" alt="A Special 2-Rail Flexible Transfer Truck" title="A Special 2-Rail Flexible Transfer Truck" />
+
+<p class="caption" style="text-align: center">Fig. 76. A Special 2-Rail Flexible Transfer Truck.</p>
+</div>
+
+<p>In <a href="#Fig_77">Figure 77</a> will be seen the Regular Transfer Car designed
+for the handling of stave bolt trucks.</p>
+
+<p>In <a href="#Fig_78">Figure 78</a> will be seen another type of Regular Transfer
+Car designed for the handling of stave bolt trucks.</p>
+
+<p>In <a href="#Fig_79">Figure 79</a> will be seen a Special Transfer Car designed
+for the handling of stave bolt trucks.<span class='pagenum'><a name="Page_228" id="Page_228">[228]</a></span></p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_77" id="Fig_77"></a></p>
+<img src="images/fig77.jpg" width="500" height="190" alt="A Regular Transfer Car for handling Stave Bolt Trucks" title="A Regular Transfer Car for handling Stave Bolt Trucks" />
+
+<p class="caption" style="text-align: center">Fig. 77. A Regular Transfer Car for handling Stave Bolt Trucks.</p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_78" id="Fig_78"></a></p>
+<img src="images/fig78.jpg" width="500" height="274" alt="A Regular Transfer Car for handling Stave Bolt Trucks" title="A Regular Transfer Car for handling Stave Bolt Trucks" />
+
+<p class="caption" style="text-align: center">Fig. 78. A Regular Transfer Car for handling Stave Bolt Trucks.</p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_79" id="Fig_79"></a></p>
+<img src="images/fig79.jpg" width="500" height="159" alt="A Special Transfer Car for handling Stave Bolt Trucks" title="A Special Transfer Car for handling Stave Bolt Trucks" />
+
+<p class="caption" style="text-align: center">Fig. 79. A Special Transfer Car for handling Stave Bolt Trucks.<span class='pagenum'><a name="Page_229" id="Page_229">[229]</a></span></p>
+</div>
+
+<p>In <a href="#Fig_80">Figure 80</a> will be seen the Regular Channel-iron
+Kiln Truck designed for edge piling "cross-wise" of the
+dry kiln.</p>
+
+<p>In <a href="#Fig_81">Figure 81</a> will be seen another type of Regular Channel-iron
+Kiln Truck designed for edge piling "cross-wise"
+of the dry kiln.</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_80" id="Fig_80"></a></p>
+<img src="images/fig80.jpg" width="500" height="192" alt="A Regular Channel-iron Kiln Truck" title="A Regular Channel-iron Kiln Truck" />
+
+<p class="caption" style="text-align: center">Fig. 80. A Regular Channel-iron Kiln Truck.</p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_81" id="Fig_81"></a></p>
+<img src="images/fig81.jpg" width="500" height="165" alt="A Regular Channel-iron Kiln Truck" title="A Regular Channel-iron Kiln Truck" />
+
+<p class="caption" style="text-align: center">Fig. 81. A Regular Channel-iron Kiln Truck.<span class='pagenum'><a name="Page_230" id="Page_230">[230]</a></span></p>
+</div>
+
+<p>In <a href="#Fig_82">Figure 82</a> will be seen the Regular Channel-iron
+Kiln Truck designed for flat piling "end-wise" of the dry
+kiln.</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_82" id="Fig_82"></a></p>
+<img src="images/fig82.jpg" width="500" height="171" alt="A Regular Channel-iron Kiln Truck" title="A Regular Channel-iron Kiln Truck" />
+
+<p class="caption" style="text-align: center">Fig. 82. A Regular Channel-iron Kiln Truck.</p>
+</div>
+
+
+<p>In<a href="#Fig_83"> Figure 83</a> will be seen the Regular Channel-iron
+Kiln Truck with I-Beam cross-pieces designed for flat
+piling "end-wise" of the dry kiln.</p>
+
+<p>In<a href="#Fig_84"> Figure 84</a> will be seen the Regular Small Dolly Kiln
+Truck designed for flat piling "end-wise" of the dry kiln.<span class='pagenum'><a name="Page_231" id="Page_231">[231]</a></span></p>
+
+<div class="figcenter" style="width: 500px"><p class="anchor"><a name="Fig_83" id="Fig_83"></a></p>
+<img src="images/fig83.jpg" width="500" height="198" alt="A Regular Channel-iron Kiln Truck" title="A Regular Channel-iron Kiln Truck" />
+
+<p class="caption" style="text-align: center">Fig. 83. A Regular Channel-iron Kiln Truck.</p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_84" id="Fig_84"></a></p>
+<img src="images/fig84.jpg" width="500" height="264" alt="A Regular Single-sill or Dolly Kiln Truck" title="A Regular Single-sill or Dolly Kiln Truck" />
+
+<p class="caption" style="text-align: center">Fig. 84. A Regular Single-sill or Dolly Kiln Truck.</p>
+</div>
+
+<h4>Different Types of Kiln Doors</h4>
+
+<p>In <a href="#Fig_85">Figure 85</a> will be seen the Asbestos-lined Door. The
+construction of this kiln door is such that it has no tendency
+to warp or twist. The framework is solid and the body
+is made of thin slats placed so that the slat on either side
+covers the open space of the other with asbestos roofing
+fabric in between. This makes a comparatively light
+and inexpensive door, and one that absolutely holds the
+heat. These doors may be built either swinging, hoisting,
+or sliding.</p>
+
+<div class="figcenter" style="width: 350px;"><p class="anchor"><a name="Fig_85" id="Fig_85"></a></p>
+<img src="images/fig85.jpg" width="350" height="451" alt="An Asbestos-lined Kiln Door of the Hinge Type" title="An Asbestos-lined Kiln Door of the Hinge Type" />
+
+<p class="caption" style="text-align: center">Fig. 85. An Asbestos-lined Kiln Door of the Hinge Type.</p>
+</div>
+
+<p>In <a href="#Fig_86">Figure 86</a> will be seen the Twin Carrier type of door
+hangers with doors loaded and rolling clear of the opening.<span class='pagenum'><a name="Page_232" id="Page_232">[232]</a></span></p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_86" id="Fig_86"></a></p>
+<img src="images/fig86.jpg" width="500" height="352" alt="Twin Carrier with Kiln Door loaded and rolling clear of Opening" title="Twin Carrier with Kiln Door loaded and rolling clear of Opening" />
+
+<p class="caption" style="text-align: center">Fig. 86. Twin Carrier with Kiln Door loaded and rolling clear of Opening.</p>
+</div>
+
+<p>In <a href="#Fig_87">Figure 87</a> will be seen the Twin Carrier for doors 18
+to 35 feet wide, idle on a section of the track.</p>
+
+<p>In <a href="#Fig_88">Figure 88</a> will be seen another type of carrier for kiln
+doors.</p>
+
+<p>In <a href="#Fig_89">Figure 89</a> will be seen the preceding type of kiln door
+carrier in operation.</p>
+
+<p>In <a href="#Fig_90">Figure 90</a> will be seen another type of carrier for
+kiln doors.</p>
+
+<p>In <a href="#Fig_91">Figure 91</a> will be seen kiln doors seated, wood construction,
+showing 3<span class="above">1</span>&#8260;<span class="below">2</span>" &times; 5<span class="above">3</span>&#8260;<span class="below">4</span>" inch-track timbers and
+trusses, supported on 4-inch by 6-inch jamb posts. "T"
+rail track, top and side, inclined shelves on which the kiln
+door rests. Track timber not trussed on openings under
+12 feet wide.</p>
+
+<div class="figcenter" style="width: 500px"><p class="anchor"><a name="Fig_87" id="Fig_87"></a></p>
+<img src="images/fig87.jpg" width="500" height="369" alt="Twin Carriers for Kiln Doors 18 to 35 Feet wide" title="Twin Carriers for Kiln Doors 18 to 35 Feet wide" />
+
+<p class="caption" style="text-align: center">Fig. 87. Twin Carriers for Kiln Doors 18 to 35 Feet wide.<span class='pagenum'><a name="Page_233" id="Page_233">[233]</a></span></p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_88" id="Fig_88"></a></p>
+<img src="images/fig88.jpg" width="500" height="424" alt=" Kiln Door Carrier engaged to Door Ready for lifting" title=" Kiln Door Carrier engaged to Door Ready for lifting" />
+
+<p class="caption" style="text-align: center">Fig. 88. Kiln Door Carrier engaged to Door Ready for lifting.</p>
+</div>
+
+<p>In <a href="#Fig_92">Figure 92</a> will be seen kiln doors seated, fire-proof
+construction, showing 12-inch, channel, steel lintels, 2" &times; 2"
+steel angle mullions, track brackets bolted to the steel
+lintels and "T" rail track. No track timbers or trusses
+used.<span class='pagenum'><a name="Page_234" id="Page_234">[234]</a></span></p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_89" id="Fig_89"></a></p>
+<img src="images/fig89.jpg" width="500" height="236" alt="Kiln Door Carrier shown on Doors of Wood Construction" title="Kiln Door Carrier shown on Doors of Wood Construction" />
+
+<p class="caption" style="text-align: center">Fig. 89. Kiln Door Carrier shown on Doors of Wood Construction.<span class='pagenum'><a name="Page_235" id="Page_235">[235]</a></span></p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_90" id="Fig_90"></a></p>
+<img src="images/fig90.jpg" width="500" height="370" alt="Kiln Door Construction with Door Carrier out of Sight" title="Kiln Door Construction with Door Carrier out of Sight" />
+
+<p class="caption" style="text-align: center">Fig. 90. Kiln Door Construction with Door Carrier out of Sight.</p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_91" id="Fig_91"></a></p>
+<img src="images/fig91.jpg" width="500" height="247" alt="Kiln Door Construction. Doors Seated. Wood Construction." title="Kiln Door Construction. Doors Seated. Wood Construction." />
+
+<p class="caption" style="text-align: center">Fig. 91. Kiln Door Construction. Doors Seated. Wood Construction.<span class='pagenum'><a name="Page_236" id="Page_236">[236]</a></span></p>
+</div>
+
+<div class="figcenter" style="width: 500px; padding-top: 2em"><p class="anchor"><a name="Fig_92" id="Fig_92"></a></p>
+<img src="images/fig92.jpg" width="500" height="253" alt="Kiln Door Construction. Doors Seated. Fire-proof Construction." title="Kiln Door Construction. Doors Seated. Fire-proof Construction." />
+
+<p class="caption" style="text-align: center">Fig. 92. Kiln Door Construction. Doors Seated. Fire-proof Construction.</p>
+</div>
+
+
+<h3 style="padding-bottom: 0em"><a name="SECTION_XIV" id="SECTION_XIV"></a>SECTION XIV<span class='pagenum'><a name="Page_237" id="Page_237">[237]</a></span></h3>
+
+<h2 style="padding-bottom: 1em">HELPFUL APPLIANCES IN
+KILN-DRYING</h2>
+
+
+<h4>The Humidity Diagram</h4>
+
+<p class="anchor"><a name="Fig_93" id="Fig_93"></a></p>
+
+<p class="figcenter"><a href="images/fig93.jpg"><img src="images/fig93_th.jpg"
+alt="Humidity Diagram" title="Humidity Diagram" /></a></p>
+
+<p class="caption" style="width: 50%; margin-left: auto; margin-right: auto">Fig. 93. The United States Forest Service Humidity Diagram for
+determination of Absolute Humidities. Dew Points and Vapor Pressures; also Relative
+Humidities by means of Wet and Dry-Bulb Thermometer, for any temperatures and change
+in temperature.</p>
+
+<p><span class="smcap">Some</span> simple means of determining humidities and
+changes in humidity brought about by changes in temperature
+in the dry kiln without the use of tables is almost
+a necessity. To meet this requirement the United States
+Forestry Service has devised the Humidity Diagram shown
+in <a href="#Fig_93">Figure 93</a>. It differs in several respects from the hydrodeiks
+now in use.</p>
+
+<p>The purpose of the humidity diagram is to enable the
+dry-kiln operator to determine quickly the humidity conditions
+and vapor pressure, as well as the changes which
+take place with changes of temperature. The diagram
+above is adapted to the direct solution of problems of
+this character without recourse to tables or mathematical
+calculations.</p>
+
+<p>The humidity diagram consists of two distinct sets of
+curves on the same sheet. One set, the convex curves,
+is for the determination of relative humidity of wet-and-dry-bulb
+hygrometer or psychrometer; the other, the concave
+curves, is derived from the vapor pressures and shows
+the amount of moisture per cubic foot at relative humidities
+and temperatures when read at the dew-point. The
+latter curves, therefore, are independent of all variables
+affecting the wet-bulb readings. They are proportional
+to vapor pressures, not to density, and, therefore, may be
+followed from one temperature to another with correctness.
+The short dashes show the correction (increase or decrease)
+which is necessary in the relative humidity, read from the
+convex curves, with an increase or decrease from the normal
+barometric pressure of 30 inches, for which the curves<span class='pagenum'><a name="Page_238" id="Page_238">[238]</a></span>
+have been plotted. This correction, except for very low
+temperatures, is so small that it may usually be disregarded.</p>
+
+<p>The ordinates, or vertical distances, are relative humidity
+expressed in per cent of saturation, from 0 per cent
+at the bottom to 100 per cent at the top. The abscissae, or
+horizontal distances, are temperatures in degrees Fahrenheit
+from 30 degrees below zero, at the left, to 220 degrees above,
+at the right.</p>
+
+
+<h4>Examples of Use</h4>
+
+<p>The application of the humidity diagram can best be
+understood by sample problems. These problems also
+show the wide range of conditions to which the diagram
+will apply.</p>
+
+<div class="example"><p><span class="smcap">Example 1.</span> To find the relative humidity by use of wet-and-dry-bulb
+hygrometer or psychrometer:</p>
+
+<div class="blockquot2">
+<p>Place the instrument in a strong circulation of air, or
+wave it to and fro. Read the temperature of the dry bulb
+and the wet, and subtract. Find on the horizontal line
+the temperature shown by the dry-bulb thermometer.
+Follow the vertical line from this point till it intersects
+with the convex curve marked with the difference between
+the wet and dry readings. The horizontal line passing
+through this intersection will give the relative humidity.</p>
+
+<p>Example: Dry bulb 70&deg;, wet bulb 62&deg;, difference 8&deg;.
+Find 70&deg; on the horizontal line of temperature. Follow
+up the vertical line from 70&deg; until it intersects with the
+convex curve marked 8&deg;. The horizontal line passing
+through this intersection shows the relative humidity to be
+64 per cent.</p>
+</div>
+
+<p><span class="smcap">Example 2.</span> To find how much water per cubic foot is contained
+in the air:</p>
+
+<div class="blockquot2">
+<p>Find the relative humidity as in example 1. Then the
+nearest concave curve gives the weight of water in grains
+per cubic foot when the air is cooled to the dew-point.
+Using the same quantities as in example 1, this will be
+slightly more than 5 grains.</p>
+</div>
+
+<p><span class="smcap">Example 3.</span> To find the amount of water required to saturate
+air at a given temperature:</p>
+
+<div class="blockquot2">
+<p>Find on the top line (100 per cent humidity) the given
+temperature; the concave curve intersecting at or near<span class='pagenum'><a name="Page_239" id="Page_239">[239]</a></span>
+this point gives the number of grains per cubic foot.
+(Interpolate, if great accuracy is desired.)</p>
+</div>
+
+<p><span class="smcap">Example 4.</span> To find the dew-point:</p>
+
+<div class="blockquot2">
+<p>Obtain the relative humidity as in example 1. Then
+follow up parallel to the nearest concave curve until the
+top horizontal (indicating 100 per cent relative humidity)
+is reached. The temperature on this horizontal line at
+the point reached will be the dew-point.</p>
+
+<p>Example: Dry bulb 70&deg;, wet bulb 62&deg;. On the vertical
+line for 70&deg; find the intersection with the hygrometer
+(convex) curve for 8&deg;. This will be found at nearly 64 per
+cent relative humidity. Then follow up parallel with the
+vapor pressure (concave) curve marked 5 grains to its
+intersection at the top of the chart with the 100 per cent
+humidity line. This gives the dew-point as 57&deg;.</p>
+</div>
+
+<p><span class="smcap">Example 5.</span> To find the change in the relative humidity produced
+by a change in temperature:</p>
+
+<div class="blockquot2">
+<p>Example: The air at 70&deg; Fahr. is found to contain 64
+per cent humidity; what will be its relative humidity if
+heated to 150&deg; Fahr.? Starting from the intersection of
+the designated humidity and temperature coordinates,
+follow the vapor-pressure curve (concave) until it intersects
+the 150&deg; temperature ordinate. The horizontal line
+then reads 6 per cent relative humidity. The same operation
+applies to reductions in temperature. In the above
+example what is the humidity at 60&deg;? Following parallel to
+the same curve in the opposite direction until it intersects
+the 60&deg; ordinate gives 90 per cent; at 57&deg; it becomes 100
+per cent, reaching the dew-point.</p>
+</div>
+
+<p><span class="smcap">Example 6.</span> To find the amount of condensation produced by
+lowering the temperature:</p>
+
+<div class="blockquot2">
+<p>Example: At 150&deg; the wet bulb reads 132&deg;. How much
+water would be condensed if the temperature were lowered
+to 70&deg;? The intersection of the hygrometer curve for 18&deg;
+(150&deg;-132&deg;) with temperature line for 150&deg; shows a relative
+humidity of 60 per cent. The vapor-pressure curve
+(concave) followed up to the 100 per cent relative humidity
+line shows 45 grains per cubic foot at the dew-point, which
+corresponds to a temperature of 130&deg;. At 70&deg; it is seen
+that the air can contain but 8 grains per cubic foot (saturation).
+Consequently, there will be condensed 45 minus 8, or
+37 grains per cubic foot of space measured at the dew-point.<span class='pagenum'><a name="Page_240" id="Page_240">[240]</a></span></p>
+</div>
+
+<p><span class="smcap">Example</span> 7. To find the amount of water required to produce
+saturation by a given rise in temperature:</p>
+
+<div class="blockquot2">
+<p>Example: Take the values given in example 5. The air
+at the dew-point contains slightly over 5 grains per cubic
+foot. At 150&deg; it is capable of containing 73 grains per
+cubic foot. Consequently, 73-5=68 grains of water
+which can be evaporated per cubic foot of space at the
+dew-point when the temperature is raised to 150&deg;. But
+the latent heat necessary to produce evaporation must be
+supplied in addition to the heat required to raise the air
+to 150&deg;.</p>
+</div>
+
+<p><span class="smcap">Example</span> 8. To find the amount of water evaporated during
+a given change of temperature and humidity:</p>
+
+<div class="blockquot2">
+<p>Example: At 70&deg; suppose the humidity is found to be
+64 per cent and at 150&deg; it is found to be 60 per cent. How
+much water has been evaporated per cubic foot of space?
+At 70&deg; temperature and 64 per cent humidity there are
+5 grains of water present per cubic foot at the dew-point
+(example 2). At 150&deg; and 60 per cent humidity there are
+45 grains present. Therefore, 45-5=40 grains of water
+which have been evaporated per cubic foot of space,
+figuring all volumes at the dew-point.</p>
+</div>
+
+<p><span class="smcap">Example</span> 9. To correct readings of the hygrometer for changes
+in barometric pressure:</p>
+
+<div class="blockquot2">
+<p>A change of pressure affects the reading of the wet bulb.
+The chart applies at a barometric pressure of 30 inches,
+and, except for great accuracy, no correction is generally
+necessary.</p>
+
+<p>Find the relative humidity as usual. Then look for the
+nearest barometer line (indicated by dashes). At the end
+of each barometer line will be found a fraction which represents
+the proportion of the relative humidity already found,
+which must be added or subtracted for a change in barometric
+pressure. If the barometer reading is less than
+30 inches, add; if greater than 30 inches, subtract. The
+figures given are for a change of 1 inch; for other changes
+use proportional amounts. Thus, for a change of 2 inches
+use twice the indicated ratio; for half an inch use half,
+and so on.</p>
+
+<p>Example: Dry bulb 67&deg;, wet bulb 51&deg;, barometer 28
+inches. The relative humidity is found, by the method
+given in example 1, to equal 30 per cent. The barometric<span class='pagenum'><a name="Page_241" id="Page_241">[241]</a></span>
+line&mdash;gives a value of 3/100H for each inch of change.
+Since the barometer is 2 inches below 30, multiply
+3/100H by 2, giving 6/100H. The correction will, therefore,
+be 6/100 of 30, which equals 1.8. Since the barometer
+is below 30, this is to be added, giving a corrected relative
+humidity of 31.8 per cent.</p>
+
+<p>This has nothing to do with the vapor pressure (concave)
+curves, which are independent of barometric pressure, and
+consequently does not affect the solution of the previous
+problems.</p>
+</div>
+
+<p><span class="smcap">Example</span> 10. At what temperature must the condenser be
+maintained to produce a given humidity?</p>
+
+<div class="blockquot2">
+<p>Example: Suppose the temperature in the drying room
+is to be kept at 150&deg; Fahr., and a humidity of 80 per cent
+is desired. If the humidity is in excess of 80 per cent the
+air must be cooled to the dew-point corresponding to this
+condition (see example 4), which in this case is 141.5&deg;.</p>
+
+<p>Hence, if the condenser cools the air to this dew point
+the required condition is obtained when the air is again
+heated to the initial temperature.</p>
+</div>
+
+<p><span class="smcap">Example</span> 11. Determination of relative humidity by the dew-point:</p>
+
+<div class="blockquot2">
+<p>The quantity of moisture present and relative humidity
+for any given temperature may be determined directly
+and accurately by finding the dew-point and applying the
+concave (vapor-pressure) curves. This does away with
+the necessity for the empirical convex curves and wet-and-dry-bulb
+readings. To find the dew-point some form
+of apparatus, consisting essentially of a thin glass vessel
+containing a thermometer and a volatile liquid, such as
+ether, may be used. The vessel is gradually cooled through
+the evaporation of the liquid, accelerated by forcing air
+through a tube until a haze or dimness, due to condensation
+from the surrounding air, first appears upon the brighter
+outer surface of the glass. The temperature at which the
+haze first appears is the dew-point. Several trials should
+be made for this temperature determination, using the
+average temperature at which the haze appears and
+disappears.</p>
+
+<p>To determine the relative humidity of the surrounding
+air by means of the dew-point thus determined, find the
+concave curve intersecting the top horizontal (100 per<span class='pagenum'><a name="Page_242" id="Page_242">[242]</a></span>
+cent relative humidity) line nearest the dew-point temperature.
+Follow parallel with this curve till it intersects
+the vertical line representing the temperature of the surrounding
+air. The horizontal line passing through this
+intersection will give the relative humidity.</p>
+
+<p>Example: Temperature of surrounding air is 80; dew-point
+is 61; relative humidity is 53 per cent.</p>
+
+<p>The dew-point determination is, however, not as convenient
+to make as the wet-and-dry-bulb hygrometer
+readings. Therefore, the hygrometer (convex) curves are
+ordinarily more useful in determining relative humidities.</p></div>
+</div>
+
+<h4>The Hygrodeik</h4>
+
+<p>In <a href="#Fig_94">Figure 94</a> will be seen the Hygrodeik. This instrument
+is used to determine the amount of moisture in the
+atmosphere. It is a very useful instrument, as the readings
+may be taken direct with accuracy.</p>
+
+<p>To find the relative humidity in the atmosphere, swing
+the index hand to the left of the chart, and adjust the
+sliding pointer to that degree of the wet-bulb thermometer
+scale at which the mercury stands. Then swing the index
+hand to the right until the sliding pointer intersects the
+curved line, which extends downwards to the left from
+the degree of the dry-bulb thermometer scale, indicated
+by the top of the mercury column in the dry-bulb tube.</p>
+
+<p>At that intersection, the index hand will point to the
+relative humidity on scale at bottom of chart (for example
+see <a href="#Fig_94">Fig. 94</a>). Should the temperature indicated by the
+wet-bulb thermometer be 60 degrees, and that of the dry-bulb
+70 degrees, the index hand will indicate humidity
+55 degrees, when the pointer rests on the intersecting
+line of 60 degrees and 80 degrees.</p>
+
+
+<h4>The Recording Hygrometer</h4>
+
+<p>In <a href="#Fig_95">Figure 95</a> is shown the Recording Hygrometer complete
+with wet and dry bulbs, two connecting tubes and
+two recording pens and special moistening device for
+supplying water to the wet bulb.</p>
+
+<p>This equipment is designed particularly for use in connection
+with dry rooms and dry kilns and is arranged so<span class='pagenum'><a name="Page_243" id="Page_243">[243]</a></span>
+that the recording instrument and the water supply bottle
+may be installed outside of the dry kiln or drying room,
+while the wet and dry bulbs are both installed inside the
+room or kiln at the point where it is desired to measure
+the humidity. This instrument records on a weekly
+chart the humidity for each hour of the day, during the
+entire week.</p>
+
+<div class="figcenter" style="width: 400px;"><p class="anchor"><a name="Fig_94" id="Fig_94"></a></p>
+<img src="images/fig94.jpg" width="400" height="501" alt="The Hygrodeik" title="The Hygrodeik" />
+
+<p class="caption" style="text-align: center">Fig. 94. The Hygrodeik.<span class='pagenum'><a name="Page_244" id="Page_244">[244]</a></span></p>
+</div>
+
+
+<h4>The Registering Hygrometer</h4>
+
+<p>In <a href="#Fig_96">Figure 96</a> is shown the Registering Hygrometer,
+which consists of two especially constructed thermometers.
+The special feature of the thermometers permits placing
+the instrument in the dry kiln without entering the drying
+room, through a small opening, where it is left for about
+20 minutes.</p>
+
+<div class="figcenter" style="width: 400px;"><p class="anchor"><a name="Fig_95" id="Fig_95"></a></p>
+<img src="images/fig95.jpg" width="400" height="320" alt=" The Recording Hygrometer" title=" The Recording Hygrometer" />
+
+<p class="caption">Fig. 95. The Recording Hygrometer, Complete with Wet and Dry Bulbs.
+This instrument records on a weekly chart the humidity for each
+hour of the day, during the entire week.</p>
+</div>
+
+<p>The temperature of both the dry and wet bulbs are
+automatically recorded, and the outside temperature will
+not affect the thermometers when removed from the kiln.
+From these recorded temperatures, as shown when the
+instrument is removed from the kiln, the humidity can
+be easily determined from a simple form of chart which
+is furnished free by the makers with each instrument.<span class='pagenum'><a name="Page_245" id="Page_245">[245]</a></span></p>
+
+
+<h4>The Recording Thermometer</h4>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_96" id="Fig_96"></a></p>
+<img src="images/fig96.jpg" width="500" height="235" alt="The Registering Hygrometer" title="The Registering Hygrometer" />
+
+<p class="caption" style="text-align: center">Fig. 96. The Registering Hygrometer.</p>
+</div>
+
+<div class="figcenter" style="width: 300px; padding-top: 2em"><p class="anchor"><a name="Fig_97" id="Fig_97"></a></p>
+<img src="images/fig97.jpg" width="300" height="311" alt="The Recording Thermometer" title="The Recording Thermometer" />
+
+<p class="caption" style="text-align: center">Fig. 97. The Recording Thermometer.</p>
+</div>
+
+<p>In <a href="#Fig_97">Figure 97</a> is shown the Recording Thermometer for
+observing and recording the temperatures within a dry
+kiln, and thus obtaining a check upon its operation. This<span class='pagenum'><a name="Page_246" id="Page_246">[246]</a></span>
+instrument is constructed to record automatically, upon
+a circular chart, the temperatures prevailing within the
+drying room at all times of the day and night, and serves
+not only as a means of keeping an accurate record of the
+operation of the dry kiln, but as a valuable check upon
+the attendant in charge of the drying
+process.</p>
+
+<table summary="illos">
+<tr><td><div class="figcenter" style="width: 100px;"><p class="anchor"><a name="Fig_98" id="Fig_98"></a></p>
+<img src="images/fig98.jpg" width="100" height="371" alt="The Registering
+Thermometer" title="The Registering
+Thermometer" />
+</div>
+<p class="caption" style="text-align: center">Fig. 98. The Registering
+Thermometer.</p></td>
+
+<td style="padding-left: 2em"><div class="figcenter" style="width: 284px;"><p class="anchor"><a name="Fig_99" id="Fig_99"></a></p>
+<img src="images/fig99.jpg" width="284" height="371" alt="The Recording Steam-Pressure
+Gauge" title="The Recording Steam-Pressure
+Gauge" />
+
+<p class="caption" style="text-align: center">Fig. 99. The Recording Steam-Pressure
+Gauge.]</p>
+</div></td></tr>
+</table>
+
+<h4>The Registering Thermometer</h4>
+
+<p>In <a href="#Fig_98">Figure 98</a> is shown the Registering
+Thermometer, which is a less expensive
+instrument than that shown
+in <a href="#Fig_97">Figure 97</a>, but by its use the maximum
+and minimum temperatures in the drying room
+during a given period can be determined.</p>
+
+
+<h4>The Recording Steam Gauge</h4>
+
+<p>In <a href="#Fig_99">Figure 99</a> is shown the Recording Steam Pressure
+Gauge, which is used for accurately recording the steam
+pressures kept in the boilers. This instrument may be<span class='pagenum'><a name="Page_247" id="Page_247">[247]</a></span>
+mounted near the boilers, or may be located at any distance
+necessary, giving a true and accurate record of the
+fluctuations of the steam pressure that may take place
+within the boilers, and is a check upon both the day and
+night boiler firemen.</p>
+
+
+<h4>The Troemroid Scalometer</h4>
+
+<p>In <a href="#Fig_100">Figure 100</a> is shown the Troemroid Scalometer. This
+instrument is a special scale of extreme accuracy, fitted
+with agate bearings with screw adjustment for balancing.
+The beam is graduated from 0 to 2 ounces, divided into
+100 parts, each division representing 1-50th of an ounce;
+and by using the pointer attached to the beam weight,
+the 1-100th part of an ounce can be weighed.</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_100" id="Fig_100"></a></p>
+<img src="images/fig100.jpg" width="500" height="370" alt="The Troemroid Scalometer" title="The Troemroid Scalometer" />
+
+<p class="caption" style="text-align: center">Fig. 100. The Troemroid Scalometer.</p>
+</div>
+
+<p>The percentage table No. II has a range from one half
+of 1 per cent to 30 per cent and is designed for use where
+extremely fine results are needed, or where a very small<span class='pagenum'><a name="Page_248" id="Page_248">[248]</a></span>
+amount of moisture is present. Table No. III ranges
+from 30 per cent up to 90 per cent. These instruments
+are in three models as described below.</p>
+
+<div class="blockquot" style="font-size: 90%"><p><span class="smcap">Model</span> A. (One cylinder) ranges from <span class="above">1</span>&#8260;<span class="below">2</span> of 1 per cent to 30
+per cent and is to be used for testing moisture contents
+in kiln-dried and air-dried lumber.</p>
+
+<p><span class="smcap">Model</span> B. (Two cylinders) ranges from <span class="above">1</span>&#8260;<span class="below">2</span> of 1 per cent up to
+90 per cent and is to be used for testing the moisture
+contents of kiln-dried, air-dried, and green lumber.</p>
+
+<p><span class="smcap">Model</span> C. (One cylinder) ranges from 30 per cent to 90 per
+cent and is applicable to green lumber only.</p></div>
+
+<p><b>Test Samples.</b>&mdash;The green boards and all other boards
+intended for testing should be selected from boards of fair
+average quality. If air-dried, select one about half way
+up the height of the pile of lumber. If kiln-dried, two
+thirds the height of the kiln car. Do not remove the kiln
+car from the kiln until after the test. Three of four test
+pieces should be cut from near the middle of the cross-wise
+section of the board, and <span class="above">1</span>&#8260;<span class="below">8</span> to <span class="above">3</span>&#8260;<span class="below">16</span> inch thick. Remove
+the superfluous sawdust and splinters. When the
+test pieces are placed on the scale pan, be sure their weight
+is less than two ounces and more than 1<span class="above">3</span>&#8260;<span class="below">4</span> ounces. If
+necessary, use two or more broken pieces. It is better if
+the test pieces can be cut off on a fine band saw.</p>
+
+<p><b>Weighing.</b>&mdash;Set the base of the scale on a level surface
+and accurately balance the scale beam. Put the test
+pieces on the scale pan and note their weight on the lower
+edge of the beam. Set the indicator point on the horizontal
+bar at a number corresponding to this weight, which
+may be found on the cylinder at the top of the table.</p>
+
+<p>Dry the test pieces on the Electric Heater (<a href="#Fig_101">Fig. 101</a>)
+30 to 40 minutes, or on the engine cylinder two or three
+hours. Weigh them at once and note the weight. Then
+turn the cylinder up and at the left of it under the small
+pointer find the number corresponding to this weight.
+The percentage of moisture lost is found directly under
+pointer on the horizontal bar first mentioned. The lower
+portion on the cylinder Table No. II is an extension of<span class='pagenum'><a name="Page_249" id="Page_249">[249]</a></span>
+the upper portion, and is manipulated in the same manner
+except that the bottom line of figures is used for the
+first weight, and the right side of cylinder for second weight.
+Turn the cylinder down instead of up when using it.</p>
+
+
+<p class="center"><b>Examples (Test Pieces)</b></p>
+
+<div class="blockquot" style="font-size: 90%"><p><span class="smcap">Model</span> A. Table No. II, Kiln-dried or Air-dried Lumber:<br />
+
+If first weight is 90<span class="above">1</span>&#8260;<span class="below">2</span> and the second weight is 87, the cylinder
+table will show the board from which the test pieces were
+taken had a moisture content of 3.8 per cent.</p>
+
+<p><span class="smcap">Model</span> B. Tables No. II and III, Air-dried (also Green and
+Kiln-dried) Lumber.<br />
+
+If the first weight on lower cylinder is 97 and the second
+weight is 76, the table will show 21.6 per cent of moisture.</p>
+
+<p><span class="smcap">Model</span> C. Table III, Green Lumber:<br />
+
+If the first weight is 94 and the second weight is 51, the
+table shows 45.8 per cent of moisture.</p></div>
+
+
+<h4>Keep Records of the Moisture Content</h4>
+
+<p><b>Saw Mills.</b>&mdash;Should test and mark each pile of lumber
+when first piled in the yard, and later when sold it should
+be again tested and the two records given to the purchaser.</p>
+
+<p><b>Factories.</b>&mdash;Should test and mark the lumber when
+first received, and if piled in the yard to be kiln-dried
+later, it should be tested before going into the dry kiln,
+and again before being removed, and these records placed
+on file for future reference.</p>
+
+<p>Kiln-dried lumber piled in storage rooms (without any
+heat) will absorb 7 to 9 per cent of moisture, and even
+when so stored should be tested for moisture before being
+manufactured into the finished product.</p>
+
+<p>Never work lumber through the factory that has more
+than 5 or 6 per cent of moisture or less than 3 per cent.</p>
+
+<p>Dry storage rooms should be provided with heating
+coils and properly ventilated.</p>
+
+<p>Oak or any other species of wood that shows 25 or 30
+per cent of moisture when going into the dry kiln, will
+take longer to dry than it would if it contained 15 to 20
+per cent, therefore the importance of testing before putting
+into the kiln as well as when taking it out.<span class='pagenum'><a name="Page_250" id="Page_250">[250]</a></span></p>
+
+
+<h4>The Electric Heater</h4>
+
+<p>In <a href="#Fig_101">Figure 101</a> is shown the Electric Heater. This
+heater is especially designed to dry quickly the test pieces
+for use in connection with the Scalometer (see <a href="#Fig_100">Fig. 100</a>)
+without charring them. It may be attached to any electric
+light socket of 110 volts direct or alternating current. A
+metal rack is provided to hold the test pieces vertically
+on edge.</p>
+
+<div class="figcenter" style="width: 500px;"><p class="anchor"><a name="Fig_101" id="Fig_101"></a></p>
+<img src="images/fig101.jpg" width="500" height="345" alt="The Electric Heater" title="The Electric Heater" />
+
+<p class="caption" style="text-align: center">Fig. 101. The Electric Heater.</p>
+</div>
+
+<p>Turn the test pieces over once or twice while drying.</p>
+
+<p>It will require from 20 minutes to one hour to remove
+all the moisture from the test pieces when placed on this
+heater, depending on whether they are cut from green,
+air-dried, or kiln-dried boards.</p>
+
+<p>Test pieces cut from softwoods will dry quicker than
+those cut from hardwoods.</p>
+
+<p>When the test pieces fail to show any further loss in
+weight, they are then free from all moisture content.</p>
+
+
+
+<h3><a name="BIBLIOGRAPHY" id="BIBLIOGRAPHY"></a>BIBLIOGRAPHY<span class='pagenum'><a name="Page_251" id="Page_251">[251]</a></span></h3>
+
+
+<ul class="bibliography">
+<li><span class="smcap">American Blower Company</span>, Detroit, Mich.</li>
+
+<li><span class="smcap">Imre, James</span> E., "The Kiln-drying of Gum," The United States
+Dept. of Agriculture, Division of Forestry.</li>
+
+<li><span class="smcap">National Dry Kiln Company</span>, Indianapolis, Ind.</li>
+
+<li><span class="smcap">Prichard, Reuben</span> P., "The Structure of the Common Woods,"
+The United States Dept. of Agriculture, Division of Forestry,
+Bulletin No. 3.</li>
+
+<li><span class="smcap">Roth, Filibert</span>, "Timber," The United States Dept. of Agriculture,
+Division of Forestry, Bulletin No. 10.</li>
+
+<li><span class="smcap">Standard Dry Kiln Company</span>, Indianapolis, Ind.</li>
+
+<li><span class="smcap">Sturtevant Company</span>, B.&nbsp;F., Boston, Mass.</li>
+
+<li><span class="smcap">Tieman</span>, H.&nbsp;D., "The Effects of Moisture upon the Strength and
+Stiffness of Wood," The United States Dept. of Agriculture,
+Division of Forestry, Bulletin No. 70.</li>
+
+<li><span class="smcap">Tieman</span>, H.&nbsp;D., "Principles of Kiln-drying Lumber," The United
+States Dept. of Agriculture, Division of Forestry.</li>
+
+<li><span class="smcap">Tieman</span>, H.&nbsp;D., "The Theory of Drying and its Application, etc.,"
+The United States Dept. of Agriculture, Division of
+Forestry, Bulletin No. 509.</li>
+
+<li><span class="smcap">The United States Dept. of Agriculture, Division of Forestry</span>,
+"Check List of the Forest Trees of the United
+States."</li>
+
+<li><span class="smcap">The United States Dept. of Agriculture, Division of
+Forestry</span>, Bulletin No. 37.</li>
+
+<li><span class="smcap">Von Schrenk, Herman</span>, "Seasoning of Timbers," The United
+States Dept. of Agriculture, Division of Forestry, Bulletin
+No. 41.</li>
+
+<li><span class="smcap">Wagner</span>, J.&nbsp;B., "Cooperage," 1910.<span class='pagenum'><a name="Page_252" id="Page_252">[252]</a></span></li>
+</ul>
+
+
+
+
+<h3><a name="GLOSSARY" id="GLOSSARY"></a>GLOSSARY<span class='pagenum'><a name="Page_253" id="Page_253">[253]</a></span></h3>
+
+
+<ul class="glossary">
+<li><b>Abnormal.</b> Differing from the usual structure.</li>
+
+<li><b>Acuminate.</b> Tapering at the end.</li>
+
+<li><b>Adhesion.</b> The union of members of different floral whorls.</li>
+
+<li><b>Air-seasoning.</b> The drying of wood in the open air.</li>
+
+<li><b>Albumen.</b>  A name applied to the food store laid up outside the
+embryo in many seeds; also nitrogenous organic matter
+found in plants.</li>
+
+<li><b>Alburnam.</b> Sapwood.</li>
+
+<li><b>Angiosperms.</b> Those plants which bear their seeds within a
+pericarp.</li>
+
+<li><b>Annual rings.</b> The layers of wood which are added annually to
+the tree.</li>
+
+<li><b>Apartment kiln.</b> A drying arrangement of one or more rooms
+with openings at each end.</li>
+
+<li><b>Arborescent.</b> A tree in size and habit of growth.</li>
+
+<li>&nbsp;</li>
+<li><b>Baffle plate.</b> An obstruction to deflect air or other currents.</li>
+
+<li><b>Bastard cut.</b> Tangential cut. Wood of inferior cut.</li>
+
+<li><b>Berry.</b> A fruit whose entire pericarp is succulent.</li>
+
+<li><b>Blower kiln.</b> A drying arrangement in which the air is blown
+through heating coils into the drying room.</li>
+
+<li><b>Box kiln.</b> A small square heating room with openings in one end
+only.</li>
+
+<li><b>Brittleness.</b> Aptness to break; not tough; fragility.</li>
+
+<li><b>Burrow.</b> A shelter; insect's hole in the wood.</li>
+
+<li>&nbsp;</li>
+
+<li><b>Calorie.</b>  Unit of heat; amount of heat which raises the
+temperature.</li>
+
+<li><b>Calyx.</b> The outer whorl of floral envelopes.</li>
+
+<li><b>Capillary.</b> A tube or vessel extremely fine or minute.</li>
+
+<li><b>Case-harden.</b> A condition in which the pores of the wood are
+closed and the outer surface dry, while the inner portion is
+still wet or unseasoned.</li>
+
+<li><b>Cavity.</b> A hollow place; a hollow.</li>
+
+<li><b>Cell.</b> One of the minute, elementary structures comprising the
+greater part of plant tissue.</li>
+
+<li><b>Cellulose.</b> A primary cell-wall substance.<span class='pagenum'><a name="Page_254" id="Page_254">[254]</a></span></li>
+
+<li><b>Checks.</b> The small chinks or cracks caused by the rupture of the
+wood fibres.</li>
+
+<li><b>Cleft.</b> Opening made by splitting; divided.</li>
+
+<li><b>Coarse-grained.</b> Wood is coarse-grained when the annual rings
+are wide or far apart.</li>
+
+<li><b>Cohesion.</b> The union of members of the same floral whorl.</li>
+
+<li><b>Contorted.</b> Twisted together.</li>
+
+<li><b>Corolla.</b> The inner whorl of floral envelopes.</li>
+
+<li><b>Cotyledon.</b> One of the parts of the embryo performing in part the
+function of a leaf, but usually serving as a storehouse of food
+for the developing plant.</li>
+
+<li><b>Crossers.</b> Narrow wooden strips used to separate the material on
+kiln cars.</li>
+
+<li><b>Cross-grained.</b> Wood is cross-grained when its fibres are spiral
+or twisted.</li>
+
+<li>&nbsp;</li>
+<li><b>Dapple.</b> An exaggerated form of mottle.</li>
+
+<li><b>Deciduous.</b> Not persistent; applied to leaves that fall in autumn
+and to calyx and corolla when they fall off before the fruit
+develops.</li>
+
+<li><b>Definite.</b> Limited or defined.</li>
+
+<li><b>Dew-point.</b> The point at which water is deposited from moisture-laden
+air.</li>
+
+<li><b>Dicotyledon.</b> A plant whose embryo has two opposite cotyledons.</li>
+
+<li><b>Diffuse.</b> Widely spreading.</li>
+
+<li><b>Disk.</b> A circular, flat, thin piece or section of the tree.</li>
+
+<li><b>Duramen.</b> Heartwood.</li>
+
+<li>&nbsp;</li>
+<li><b>Embryo.</b> Applied in botany to the tiny plant within the seed.</li>
+
+<li><b>Enchinate.</b> Beset with prickles.</li>
+
+<li><b>Expansion.</b> An enlargement across the grain or lengthwise of the
+wood.</li>
+
+<li>&nbsp;</li>
+<li><b>Fibres.</b> The thread-like portion of the tissue of wood.</li>
+
+<li><b>Fibre-saturation point.</b> The amount of moisture wood will imbibe,
+usually 25 to 30 per cent of its dry-wood weight.</li>
+
+<li><b>Figure.</b> The broad and deep medullary rays as in oak showing
+when the timber is cut into boards.</li>
+
+<li><b>Filament.</b> The stalk which supports the anther.</li>
+
+<li><b>Fine-grained.</b> Wood is fine-grained when the annual rings are
+close together or narrow.</li>
+
+<li>&nbsp;</li>
+<li><b>Germination.</b> The sprouting of a seed.</li>
+
+<li><b>Girdling.</b> To make a groove around and through the bark of a
+tree, thus killing it.<span class='pagenum'><a name="Page_255" id="Page_255">[255]</a></span></li>
+
+<li><b>Glands.</b> A secreting surface or structure; a protuberance having
+the appearance of such an organ.</li>
+
+<li><b>Glaucous.</b> Covered or whitened with a bloom.</li>
+
+<li><b>Grain.</b> Direction or arrangement of the fibres in wood.</li>
+
+<li><b>Grubs.</b> The larvae of wood-destroying insects.</li>
+
+<li><b>Gymnosperms.</b> Plants bearing naked seeds; without an ovary.</li>
+
+<li>&nbsp;</li>
+
+<li><b>Habitat.</b> The geographical range of a plant.</li>
+
+<li><b>Heartwood.</b> The central portion of tree.</li>
+
+<li><b>Hollow-horning.</b> Internal checking.</li>
+
+<li><b>Honeycombing.</b> Internal checking.</li>
+
+<li><b>Hot-blast kiln.</b> A drying arrangement in which the air is blown
+through heating coils into the drying room.</li>
+
+<li><b>Humidity.</b> Damp, moist.</li>
+
+<li><b>Hygroscopicity.</b> The property of readily imbibing moisture from
+the atmosphere.</li>
+
+<li>&nbsp;</li>
+
+<li><b>Indefinite.</b> Applied to petals or other organs when too numerous
+to be conveniently counted.</li>
+
+<li><b>Indigenous.</b> Native to the country.</li>
+
+<li><b>Involute.</b> A form of vernation in which the leaf is rolled inward
+from its edges.</li>
+
+<li>&nbsp;</li>
+
+<li><b>Kiln-drying.</b> Drying or seasoning of wood by artificial heat in an
+inclosed room.</li>
+
+<li>&nbsp;</li>
+
+<li><b>Leaflet.</b> A single division of a compound leaf.</li>
+
+<li><b>Limb.</b> The spreading portion of the tree.</li>
+
+<li><b>Lumen.</b> Internal space in the spring- and summer-wood fibres.</li>
+
+<li>&nbsp;</li>
+
+<li><b>Median.</b> Situated in the middle.</li>
+
+<li><b>Medulla.</b> The pith.</li>
+
+<li><b>Medullary rays.</b> Rays of fundamental tissue which connect the
+pith with the bark.</li>
+
+<li><b>Membranous.</b> Thin and rather soft, more or less translucent.</li>
+
+<li><b>Midrib.</b> The central or main rib of a leaf.</li>
+
+<li><b>Moist-air kiln.</b> A drying arrangement in which the heat is taken
+from radiating coils located inside the drying room.</li>
+
+<li><b>Mottle.</b> Figure transverse of the fibres, probably caused by the
+action of wind upon the tree.</li>
+
+<li>&nbsp;</li>
+
+<li><b>Non-porous.</b> Without pores.</li>
+
+<li>&nbsp;</li>
+
+<li><b>Oblong.</b> Considerably longer than broad, with flowing outline.</li>
+
+<li><b>Obtuse.</b> Blunt, rounded.<span class='pagenum'><a name="Page_256" id="Page_256">[256]</a></span></li>
+
+<li><b>Oval.</b> Broadly elliptical.</li>
+
+<li><b>Ovary.</b> The part of the pistil that contains the ovules.</li>
+
+<li>&nbsp;</li>
+
+<li><b>Parted.</b> Cleft nearly, but not quite to the base or midrib.</li>
+
+<li><b>Parenchyma.</b> Short cells constituting the pith and pulp of the
+tree.</li>
+
+<li><b>Pericarp.</b> The walls of the ripened ovary, the part of the fruit
+that encloses the seeds.</li>
+
+<li><b>Permeable.</b> Capable of being penetrated.</li>
+
+<li><b>Petal.</b> One of the leaves of the corolla.</li>
+
+<li><b>Pinholes.</b> Small holes in the wood caused by worms or insects.</li>
+
+<li><b>Pistil.</b> The modified leaf or leaves which bear the ovules; usually
+consisting of ovary, style and stigma.</li>
+
+<li><b>Plastic.</b> Elastic, easily bent.</li>
+
+<li><b>Pocket kilns.</b> Small drying rooms with openings on one end only
+and in which the material to be dried is piled directly on the
+floor.</li>
+
+<li><b>Pollen.</b> The fertilizing powder produced by the anther.</li>
+
+<li><b>Pores.</b> Minute orifices in wood.</li>
+
+<li><b>Porous.</b> Containing pores.</li>
+
+<li><b>Preliminary steaming.</b> Subjecting wood to a steaming process
+before drying or seasoning.</li>
+
+<li><b>Progressive kiln.</b> A drying arrangement with openings at both
+ends, and in which the material enters at one end and is discharged
+at the other.</li>
+
+<li>&nbsp;</li>
+
+<li><b>Rick.</b> A pile or stack of lumber.</li>
+
+<li><b>Rift.</b> To split; cleft.</li>
+
+<li><b>Ring shake.</b> A large check or crack in the wood following an
+annual ring.</li>
+
+<li><b>Roe.</b> A peculiar figure caused by the contortion of the woody
+fibres, and takes a wavy line parallel to them.</li>
+
+<li>&nbsp;</li>
+
+<li><b>Sapwood.</b> The outer portions of the tree next to the bark;
+alburnam.</li>
+
+<li><b>Saturate.</b> To cause to become completely penetrated or soaked.</li>
+
+<li><b>Season checks.</b> Small openings in the ends of the wood caused
+by the process of drying.</li>
+
+<li><b>Seasoning.</b> The process by which wood is dried or seasoned.</li>
+
+<li><b>Seedholes.</b> Minute holes in wood caused by wood-destroying
+worms or insects.</li>
+
+<li><b>Shake.</b> A large check or crack in wood caused by the action of
+the wind on the tree.</li>
+
+<li><b>Shrinkage.</b> A lessening or contraction of the wood substance.<span class='pagenum'><a name="Page_257" id="Page_257">[257]</a></span></li>
+
+<li><b>Skidways.</b> Material set on an incline for transporting lumber or
+logs.</li>
+
+<li><b>Species.</b> In science, a group of existing things, associated according
+to properties.</li>
+
+<li><b>Spermatophyta.</b> Seed-bearing plants.</li>
+
+<li><b>Spring-wood.</b> Wood that is formed in the spring of the year.</li>
+
+<li><b>Stamen.</b> The pollen-bearing organ of the flower, usually consisting
+of filament and anther.</li>
+
+<li><b>Stigma.</b> That part of the pistil which receives the pollen.</li>
+
+<li><b>Style.</b> That part of the pistil which connects the ovary with the
+stigma.</li>
+
+<li>&nbsp;</li>
+
+<li><b>Taproot.</b> The main root or downward continuation of the plant
+axis.</li>
+
+<li><b>Temporary checks.</b> Checks or cracks that subsequently close.</li>
+
+<li><b>Tissue.</b> One of the elementary fibres composing wood.</li>
+
+<li><b>Thunder shake.</b> A rupture of the fibres of the tree across the
+grain, which in some woods does not always break them.</li>
+
+<li><b>Tornado shake.</b> (See Thunder shake.)</li>
+
+<li><b>Tracheids.</b> The tissues of the tree which consist of vertical cells
+or vessels closed at one end.</li>
+
+<li>&nbsp;</li>
+
+<li><b>Warping.</b> Turning or twisting out of shape.</li>
+
+<li><b>Wind shake.</b> (See Thunder shake.)</li>
+
+<li><b>Working.</b> The shrinking and swelling occasioned in wood.</li>
+
+<li><b>Wormholes.</b> Small holes in wood caused by wood-destroying
+worms.</li>
+
+<li>&nbsp;</li>
+
+<li><b>Vernation.</b> The arrangement of the leaves in the bud.</li>
+
+<li><b>Whorl.</b> An arrangement of organs in a circle about a central axis.<span class='pagenum'><a name="Page_258" id="Page_258">[258]</a></span></li>
+</ul>
+
+
+
+
+<h3><a name="INDEX_OF_LATIN_NAMES" id="INDEX_OF_LATIN_NAMES"></a>INDEX OF LATIN NAMES<span class='pagenum'><a name="Page_259" id="Page_259">[259]</a></span></h3>
+
+<div class="twocolumns">
+<div class="column_left">
+<ul>
+<li>Abies amabalis, <a href="#Page_21">21</a></li>
+<li>Abies balsamea, <a href="#Page_20">20</a></li>
+<li>Abies concolor, <a href="#Page_20">20</a></li>
+<li>Abies grandis, <a href="#Page_20">20</a></li>
+<li>Abies magnifica, <a href="#Page_21">21</a></li>
+<li>Abies nobilis, <a href="#Page_21">21</a></li>
+<li>Acer macrophyllum, <a href="#Page_69">69</a></li>
+<li>Acer negundo, <a href="#Page_69">69</a></li>
+<li>Acer Pennsylvanicum, <a href="#Page_70">70</a></li>
+<li>Acer rubrum, <a href="#Page_69">69</a></li>
+<li>Acer saccharinum, <a href="#Page_69">69</a></li>
+<li>Acer saccharum, <a href="#Page_68">68</a></li>
+<li>Acer spicatum, <a href="#Page_69">69</a></li>
+<li>&AElig;sculus flava, <a href="#Page_45">45</a></li>
+<li>&AElig;sculus glabra, <a href="#Page_45">45</a></li>
+<li>&AElig;sculus octandra, <a href="#Page_45">45</a></li>
+<li>Ailanthus glandulosa, <a href="#Page_37">37</a></li>
+<li>Asimina triloba, <a href="#Page_76">76</a></li>
+<li>&nbsp;</li>
+
+<li>Betula lenta, <a href="#Page_41">41</a></li>
+<li>Betula lutea, <a href="#Page_42">42</a></li>
+<li>Betula nigra, <a href="#Page_43">43</a></li>
+<li>Betula papyrifera, <a href="#Page_43">43</a></li>
+<li>Betula populifolia, <a href="#Page_42">42</a></li>
+<li>Betula rubra, <a href="#Page_43">43</a></li>
+<li>Buxus sempervirens, <a href="#Page_77">77</a></li>
+<li>&nbsp;</li>
+
+
+<li>Carpinus Caroliana, <a href="#Page_44">44</a></li>
+<li>Castanea Americana, <a href="#Page_48">48</a></li>
+<li>Castanea chrysophylla, <a href="#Page_49">49</a></li>
+<li>Castanea dentata, <a href="#Page_48">48</a></li>
+<li>Castanea pumila, <a href="#Page_48">48</a></li>
+<li>Castanea vesca, <a href="#Page_48">48</a></li>
+<li>Castanea vulgaris, <a href="#Page_48">48</a></li>
+<li>Catalpa bignonioides, <a href="#Page_46">46</a></li>
+<li>Catalpa speciosa, <a href="#Page_46">46</a></li>
+<li>Celtis occidentalis, <a href="#Page_62">62</a></li>
+<li>Cham&aelig;cyparis Lawsonia, <a href="#Page_18">18</a></li>
+<li>Cham&aelig;cyparis thyoides, <a href="#Page_17">17</a></li>
+<li>Cladrastis lutea, <a href="#Page_85">85</a></li>
+<li>Cornus florida, <a href="#Page_49">49</a></li>
+<li>Cupressus nootkatensis, <a href="#Page_18">18</a></li>
+<li>&nbsp;</li>
+
+
+<li>Diospyros Virginia, <a href="#Page_77">77</a></li>
+<li>&nbsp;</li>
+
+
+<li>Evonymus atropurpureus, <a href="#Page_82">82</a></li>
+<li>&nbsp;</li>
+
+
+<li>Fagus ferruginea, <a href="#Page_40">40</a></li>
+<li>Fraxinus Americana, <a href="#Page_37">37</a></li>
+<li>Fraxinus Caroliniana, <a href="#Page_39">39</a></li>
+<li>Fraxinus nigra, <a href="#Page_38">38</a></li>
+<li>Fraxinus Oregana, <a href="#Page_38">38</a></li>
+<li>Fraxinus Pennsylvanica, <a href="#Page_38">38</a></li>
+<li>Fraxinus pubescens, <a href="#Page_38">38</a></li>
+<li>Fraxinus quadrangulata, <a href="#Page_38">38</a></li>
+<li>Fraxinus sambucifolia, <a href="#Page_38">38</a></li>
+<li>Fraxinus viridis, <a href="#Page_38">38</a></li>
+<li>&nbsp;</li>
+
+
+<li>Gleditschia triacanthos, <a href="#Page_66">66</a></li>
+<li>Gymnocladus dioicus, <a href="#Page_49">49</a></li>
+<li>&nbsp;</li>
+
+
+<li>Hicoria alba, <a href="#Page_64">64</a></li>
+<li>Hicoria glabra, <a href="#Page_64">64</a></li>
+<li>Hicoria minima, <a href="#Page_64">64</a></li>
+<li>Hicoria ovata, <a href="#Page_64">64</a></li>
+<li>Hicoria pecan, <a href="#Page_64">64</a></li>
+<li>&nbsp;</li>
+
+
+<li>Ilex monticolo, <a href="#Page_65">65</a></li>
+<li>Ilex opaca, <a href="#Page_64">64</a></li>
+<li>&nbsp;</li>
+
+
+<li>Juglans cinerea, <a href="#Page_45">45</a></li>
+<li>Juglans nigra, <a href="#Page_82">82</a></li>
+<li>Juniperus communis, <a href="#Page_19">19</a></li>
+<li>Juniperus Virginiana, <a href="#Page_18">18</a></li>
+<li>&nbsp;</li>
+
+
+<li>Larix Americana, <a href="#Page_22">22</a></li>
+<li>Larix laricina, <a href="#Page_22">22</a></li>
+<li>Larix occidentalis, <a href="#Page_22">22</a></li>
+<li>Libocedrus decurrens, <a href="#Page_18">18</a></li>
+<li>Liquidamber styraciflua, <a href="#Page_54">54</a></li>
+<li>Liriodendron tulipfera, <a href="#Page_81">81</a></li>
+<li>&nbsp;</li>
+
+
+<li>Maclura aurantiaca, <a href="#Page_76">76</a></li>
+<li>Magnolia acuminata, <a href="#Page_67">67</a></li>
+<li>Magnolia glauca, <a href="#Page_67">67</a><span class='pagenum'><a name="Page_260" id="Page_260">[260]</a></span></li>
+<li>Magnolia tripetala, <a href="#Page_67">67</a></li>
+<li>Morus rubra, <a href="#Page_70">70</a></li>
+<li>&nbsp;</li>
+
+
+<li>Nyssa aquatica, <a href="#Page_60">60</a></li>
+<li>Nyssa sylvatica, <a href="#Page_62">62</a></li>
+<li>&nbsp;</li>
+
+
+<li>Ostrya Virginiana, <a href="#Page_65">65</a></li>
+<li>Oxydendrum arboreum, <a href="#Page_80">80</a></li>
+<li>&nbsp;</li>
+
+
+<li>Picea alba, <a href="#Page_28">28</a></li>
+<li>Picea canadensis, <a href="#Page_28">28</a></li>
+<li>Picea engelmanni, <a href="#Page_28">28</a></li>
+<li>Picea mariana, <a href="#Page_27">27</a></li>
+<li>Picea nigra, <a href="#Page_27">27</a></li>
+<li>Picea rubens, <a href="#Page_28">28</a></li>
+<li>Picea sitchensis, <a href="#Page_28">28</a></li>
+<li>Pinus banksiana, <a href="#Page_27">27</a></li></ul>
+</div>
+
+<div class="column_right">
+<ul>
+<li>Pinus cubensis, <a href="#Page_26">26</a></li>
+<li>Pinus divaricata, <a href="#Page_27">27</a></li>
+<li>Pinus enchinata, <a href="#Page_26">26</a></li>
+<li>Pinus flexilis, <a href="#Page_24">24</a></li>
+<li>Pinus inops, <a href="#Page_27">27</a></li>
+<li>Pinus Jeffreyi, <a href="#Page_25">25</a></li>
+<li>Pinus Lambertiana, <a href="#Page_24">24</a></li>
+<li>Pinus monticolo, <a href="#Page_24">24</a></li>
+<li>Pinus Murryana, <a href="#Page_27">27</a></li>
+<li>Pinus palustris, <a href="#Page_24">24</a></li>
+<li>Pinus ponderosa, <a href="#Page_25">25</a></li>
+<li>Pinus resinosa, <a href="#Page_25">25</a></li>
+<li>Pinus rigida, <a href="#Page_26">26</a></li>
+<li>Pinus strobus, <a href="#Page_23">23</a></li>
+<li>Pinus t&aelig;da, <a href="#Page_25">25</a></li>
+<li>Pinus Virginiana, <a href="#Page_27">27</a></li>
+<li>Platanus occidentalis, <a href="#Page_80">80</a></li>
+<li>Platanus racemosa, <a href="#Page_81">81</a></li>
+<li>Populus alba, <a href="#Page_79">79</a></li>
+<li>Populus angulata, <a href="#Page_77">77</a></li>
+<li>Populus balsamifera, <a href="#Page_79">79</a></li>
+<li>Populus fremontii, <a href="#Page_78">78</a></li>
+<li>Populus grandidentata, <a href="#Page_79">79</a></li>
+<li>Populus heteropylla, <a href="#Page_78">78</a></li>
+<li>Populus monilifera, <a href="#Page_77">77</a></li>
+<li>Populus nigra italica, <a href="#Page_79">79</a></li>
+<li>Populus tremuloides, <a href="#Page_79">79</a></li>
+<li>Populus trichocarpa, <a href="#Page_78">78</a></li>
+<li>Populus Wislizeni, <a href="#Page_78">78</a></li>
+<li>Prunus Pennsylvanica, <a href="#Page_47">47</a></li>
+<li>Prunus serotina, <a href="#Page_47">47</a></li>
+<li>Pseudotsuga douglasii, <a href="#Page_29">29</a></li>
+<li>Pseudotsuga taxifolia, <a href="#Page_29">29</a></li>
+<li>Pyrus coronaria, <a href="#Page_49">49</a></li>
+<li>&nbsp;</li>
+
+
+<li>Quercus acuminata, <a href="#Page_73">73</a></li>
+<li>Quercus alba, <a href="#Page_71">71</a></li>
+<li>Quercus aquatica, <a href="#Page_73">73</a></li>
+<li>Quercus bicolor, <a href="#Page_72">72</a></li>
+<li>Quercus chrysolepis, <a href="#Page_76">76</a></li>
+<li>Quercus coccinea, <a href="#Page_75">75</a></li>
+<li>Quercus digitata, <a href="#Page_75">75</a></li>
+<li>Quercus durandii, <a href="#Page_71">71</a></li>
+<li>Quercus falcata, <a href="#Page_75">75</a></li>
+<li>Quercus garryana, <a href="#Page_71">71</a></li>
+<li>Quercus ilicijolia, <a href="#Page_74">74</a></li>
+<li>Quercus imbricaria, <a href="#Page_75">75</a></li>
+<li>Quercus lobata, <a href="#Page_72">72</a></li>
+<li>Quercus lyrata, <a href="#Page_73">73</a></li>
+<li>Quercus macrocarpa, <a href="#Page_72">72</a></li>
+<li>Quercus marilandica, <a href="#Page_75">75</a></li>
+<li>Quercus Michauxii, <a href="#Page_74">74</a></li>
+<li>Quercus minor, <a href="#Page_74">74</a></li>
+<li>Quercus nigra, <a href="#Page_75">75</a></li>
+<li>Quercus obtusiloda, <a href="#Page_74">74</a></li>
+<li>Quercus palustris, <a href="#Page_73">73</a></li>
+<li>Quercus phellos, <a href="#Page_72">72</a></li>
+<li>Quercus platanoides, <a href="#Page_72">72</a></li>
+<li>Quercus prinoides, <a href="#Page_74">74</a></li>
+<li>Quercus prinus, <a href="#Page_73">73</a></li>
+<li>Quercus pumila, <a href="#Page_74">74</a></li>
+<li>Quercus rubra, <a href="#Page_74">74</a></li>
+<li>Quercus tinctoria, <a href="#Page_74">74</a></li>
+<li>Quercus velutina, <a href="#Page_74">74</a></li>
+<li>Quercus virens, <a href="#Page_75">75</a></li>
+<li>&nbsp;</li>
+
+
+<li>Rhamnus Caroliniana, <a href="#Page_45">45</a></li>
+<li>Robinia pseudacacia, <a href="#Page_66">66</a></li>
+<li>Robinia viscosa, <a href="#Page_66">66</a></li>
+<li>&nbsp;</li>
+
+
+<li>Salix alba, <a href="#Page_83">83</a></li>
+<li>Salix amygdaloides, <a href="#Page_84">84</a></li>
+<li>Salix babylonica, <a href="#Page_84">84</a></li>
+<li>Salix bebbiana, <a href="#Page_84">84</a></li>
+<li>Salix discolor, <a href="#Page_84">84</a></li>
+<li>Salix fluviatilis, <a href="#Page_84">84</a></li>
+<li>Salix fragilis, <a href="#Page_84">84</a></li>
+<li>Salix lucida, <a href="#Page_84">84</a></li>
+<li>Salix nigra, <a href="#Page_83">83</a></li>
+<li>Salix rostrata, <a href="#Page_84">84</a></li>
+<li>Salix vitellina, <a href="#Page_83">83</a></li>
+<li>Sassafras sassafras, <a href="#Page_80">80</a></li>
+<li>Sequoia sempervirens, <a href="#Page_19">19</a></li>
+<li>&nbsp;</li>
+
+
+<li>Taxodium distinchum, <a href="#Page_19">19</a></li>
+<li>Taxus brevifolia, <a href="#Page_30">30</a></li>
+<li>Thuya gigantea, <a href="#Page_17">17</a></li>
+<li>Thuya occidentalis, <a href="#Page_17">17</a></li>
+<li>Tilia Americana, <a href="#Page_39">39</a></li>
+<li>Tilia heterophylla, <a href="#Page_39">39</a><span class='pagenum'><a name="Page_261" id="Page_261">[261]</a></span></li>
+<li>Tilia pubescens, <a href="#Page_39">39</a></li>
+<li>Tsuga canadensis, <a href="#Page_21">21</a></li>
+<li>Tsuga mertensiana, <a href="#Page_21">21</a></li>
+<li>&nbsp;</li>
+
+
+<li>Ulmus alata, <a href="#Page_51">51</a></li>
+<li>Ulmus Americana, <a href="#Page_50">50</a></li>
+<li>Ulmus crassifolia, <a href="#Page_51">51</a></li>
+<li>Ulmus fulva, <a href="#Page_51">51</a></li>
+<li>Ulmus pubescens, <a href="#Page_51">51</a></li>
+<li>Ulmus racemosa, <a href="#Page_50">50</a></li>
+<li>Umbellularia Californica, <a href="#Page_65">65</a></li>
+</ul>
+</div>
+<div class="clear">&nbsp;</div>
+</div>
+
+
+
+
+
+<h3><a name="INDEX" id="INDEX"></a>INDEX<span class='pagenum'><a name="Page_262" id="Page_262">[262]</a></span></h3>
+
+
+<ul class="index">
+<li><span class="smcap">Abele, Tree</span>, <a href="#Page_79">79</a></li>
+
+<li>Absorption of water by dry wood, <a href="#Page_124">124</a></li>
+
+<li>Acacia, <a href="#Page_66">66</a></li>
+
+<li>Acacia, false, <a href="#Page_66">66</a></li>
+
+<li>Acacia, three-thorned, <a href="#Page_66">66</a></li>
+
+<li>According to species, different kiln drying, <a href="#Page_170">170</a></li>
+
+<li>Advantages in seasoning, <a href="#Page_128">128</a></li>
+
+<li>Advantages of kiln-drying over air-drying, <a href="#Page_156">156</a></li>
+
+<li>Affect drying, properties of wood that, <a href="#Page_156">156</a></li>
+
+<li>Ailanthus, <a href="#Page_37">37</a></li>
+
+<li>Air circulation, <a href="#Page_173">173</a></li>
+
+<li>Air-drying, advantages of kiln-drying over, <a href="#Page_156">156</a></li>
+
+<li>Alaska cedar, <a href="#Page_18">18</a></li>
+
+<li>Alaska cypress, <a href="#Page_18">18</a></li>
+
+<li>Alcoholic liquids, stave and heads of barrels containing, <a href="#Page_112">112</a></li>
+
+<li>Almond-leaf willow, <a href="#Page_84">84</a></li>
+
+<li>Ambrosia or timber beetles, <a href="#Page_99">99</a></li>
+
+<li>American box, <a href="#Page_49">49</a></li>
+
+<li>American elm, <a href="#Page_50">50</a></li>
+
+<li>American larch, <a href="#Page_22">22</a></li>
+
+<li>American linden, <a href="#Page_39">39</a></li>
+
+<li>American oak, <a href="#Page_71">71</a></li>
+
+<li>American red pine, <a href="#Page_25">25</a></li>
+
+<li>Anatomical structure, <a href="#Page_14">14</a></li>
+
+<li>Annual ring, the yearly or, <a href="#Page_10">10</a></li>
+
+<li>Apartment dry kiln, <a href="#Page_198">198</a></li>
+
+<li>Apple, crab, <a href="#Page_49">49</a></li>
+
+<li>Apple, custard, <a href="#Page_76">76</a></li>
+
+<li>Apple, wild, <a href="#Page_49">49</a></li>
+
+<li>Appliances in kiln-drying, helpful, <a href="#Page_237">237</a></li>
+
+<li>Arborvit&aelig;, <a href="#Page_17">17</a></li>
+
+<li>Ash, <a href="#Page_37">37</a></li>
+
+<li>Ash, black, <a href="#Page_38">38</a></li>
+
+<li>Ash, blue, <a href="#Page_38">38</a></li>
+
+<li>Ash, Carolina, <a href="#Page_39">39</a></li>
+
+<li>Ash, green, <a href="#Page_38">38</a></li>
+
+<li>Ash, ground, <a href="#Page_38">38</a></li>
+
+<li>Ash, hoop, <a href="#Page_38">38</a></li>
+
+<li>Ash-leaved maple, <a href="#Page_69">69</a></li>
+
+<li>Ash, Oregon, <a href="#Page_38">38</a></li>
+
+<li>Ash, red, <a href="#Page_38">38</a></li>
+
+<li>Ash, white, <a href="#Page_37">37</a></li>
+
+<li>Aspen, <a href="#Page_39">39</a>, <a href="#Page_79">79</a></li>
+
+<li>Aspen, large-toothed, <a href="#Page_78">78</a></li>
+
+<li>Aspen-leaved birch, <a href="#Page_42">42</a></li>
+
+<li>Aspen, quaking, <a href="#Page_79">79</a></li>
+
+<li>Atmospheric pressure, drying at, <a href="#Page_146">146</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Bald Cypress</span>, <a href="#Page_19">19</a></li>
+
+<li>Ball tree, button, <a href="#Page_80">80</a></li>
+
+<li>Balm of gilead, <a href="#Page_79">79</a></li>
+
+<li>Balm of gilead fir, <a href="#Page_20">20</a></li>
+
+<li>Balsam, <a href="#Page_20">20</a>, <a href="#Page_79">79</a></li>
+
+<li>Balsam fir, <a href="#Page_20">20</a></li>
+
+<li>Bark and pith, <a href="#Page_8">8</a></li>
+
+<li>Bark on, round timber with, <a href="#Page_106">106</a></li>
+
+<li>Barrels containing alcoholic liquids, staves and heads of, <a href="#Page_112">112</a></li>
+
+<li>Barren oak, <a href="#Page_75">75</a></li>
+
+<li>Bar willow, sand, <a href="#Page_84">84</a></li>
+
+<li>Basket oak, <a href="#Page_74">74</a></li>
+
+<li>Basswood, <a href="#Page_39">39</a></li>
+
+<li>Basswood, small-leaved, <a href="#Page_39">39</a></li>
+
+<li>Basswood, white, <a href="#Page_39">39</a></li>
+
+<li>Bastard pine, <a href="#Page_26">26</a></li>
+
+<li>Bastard spruce, <a href="#Page_29">29</a></li>
+
+<li>Bay poplar, <a href="#Page_60">60</a></li>
+
+<li>Bay, sweet, <a href="#Page_67">67</a></li>
+
+<li>Bear oak, <a href="#Page_74">74</a></li>
+
+<li>Beaver wood, <a href="#Page_67">67</a></li>
+
+<li>Bebb willow, <a href="#Page_84">84</a></li>
+
+<li>Bee tree, <a href="#Page_39">39</a></li>
+
+<li>Beech, <a href="#Page_40">40</a></li>
+
+<li>Beech, blue, <a href="#Page_44">44</a></li>
+
+<li>Beech, red, <a href="#Page_40">40</a></li>
+
+<li>Beech, water, <a href="#Page_44">44</a>, <a href="#Page_80">80</a></li>
+
+<li>Beech, white, <a href="#Page_40">40</a></li>
+
+<li>Berry, sugar, <a href="#Page_62">62</a></li>
+
+<li>Beetles, ambrosia or timber, <a href="#Page_99">99</a><span class='pagenum'><a name="Page_263" id="Page_263">[263]</a></span></li>
+
+<li>Big bud hickory, <a href="#Page_64">64</a></li>
+
+<li>Bilsted, <a href="#Page_54">54</a></li>
+
+<li>Birch, <a href="#Page_41">41</a></li>
+
+<li>Birch, aspen-leaved, <a href="#Page_42">42</a></li>
+
+<li>Birch, black, <a href="#Page_41">41</a></li>
+
+<li>Birch, canoe, <a href="#Page_43">43</a></li>
+
+<li>Birch, cherry, <a href="#Page_41">41</a></li>
+
+<li>Birch, gray, <a href="#Page_42">42</a></li>
+
+<li>Birch, mahogany, <a href="#Page_41">41</a></li>
+
+<li>Birch, old field, <a href="#Page_42">42</a></li>
+
+<li>Birch, paper, <a href="#Page_43">43</a></li>
+
+<li>Birch, red, <a href="#Page_42">42</a></li>
+
+<li>Birch, river, <a href="#Page_43">43</a></li>
+
+<li>Birch, silver, <a href="#Page_42">42</a></li>
+
+<li>Birch, sweet, <a href="#Page_41">41</a></li>
+
+<li>Birch, white, <a href="#Page_42">42</a>, <a href="#Page_43">43</a></li>
+
+<li>Birch, wintergreen, <a href="#Page_41">41</a></li>
+
+<li>Birch, yellow, <a href="#Page_42">42</a></li>
+
+<li>Bird cherry, <a href="#Page_47">47</a></li>
+
+<li>Bitternut hickory, <a href="#Page_64">64</a></li>
+
+<li>Black ash, <a href="#Page_38">38</a></li>
+
+<li>Black birch, <a href="#Page_41">41</a></li>
+
+<li>Black cherry, <a href="#Page_47">47</a></li>
+
+<li>Black cottonwood, <a href="#Page_78">78</a></li>
+
+<li>Black cypress, <a href="#Page_19">19</a></li>
+
+<li>Black gum, <a href="#Page_62">62</a></li>
+
+<li>Black hickory, <a href="#Page_64">64</a></li>
+
+<li>Black jack, <a href="#Page_75">75</a></li>
+
+<li>Black larch, <a href="#Page_22">22</a></li>
+
+<li>Black locust, <a href="#Page_66">66</a></li>
+
+<li>Black nut hickory, <a href="#Page_64">64</a></li>
+
+<li>Black oak, <a href="#Page_74">74</a></li>
+
+<li>Black pine, <a href="#Page_25">25</a>, <a href="#Page_27">27</a></li>
+
+<li>Black spruce, <a href="#Page_27">27</a></li>
+
+<li>Black walnut, <a href="#Page_44">44</a>, <a href="#Page_82">82</a></li>
+
+<li>Black willow, <a href="#Page_83">83</a></li>
+
+<li>Blower dry kiln, operation of, <a href="#Page_186">186</a></li>
+
+<li>Blower or hot blast dry kiln, <a href="#Page_185">185</a></li>
+
+<li>Blue ash, <a href="#Page_38">38</a></li>
+
+<li>Blue beech, <a href="#Page_44">44</a></li>
+
+<li>Blue poplar, <a href="#Page_81">81</a></li>
+
+<li>Blue willow, <a href="#Page_83">83</a></li>
+
+<li>Bois d'Arc, <a href="#Page_45">45</a>, <a href="#Page_76">76</a></li>
+
+<li>Bolts, stave, heading and shingle, <a href="#Page_109">109</a></li>
+
+<li>Borers, flat-headed, <a href="#Page_103">103</a></li>
+
+<li>Borers, powder post, <a href="#Page_105">105</a></li>
+
+<li>Borers, round-headed, <a href="#Page_101">101</a></li>
+
+<li>Box, American, <a href="#Page_49">49</a></li>
+
+<li>Box elder, <a href="#Page_69">69</a></li>
+
+<li>Box dry kiln, <a href="#Page_204">204</a></li>
+
+<li>Broad-leaved maple, <a href="#Page_69">69</a></li>
+
+<li>Broad-leaved trees, <a href="#Page_31">31</a></li>
+
+<li>Broad-leaved trees, list of most important, <a href="#Page_37">37</a></li>
+
+<li>Broad-leaved trees, wood of, <a href="#Page_31">31</a></li>
+
+<li>Brown hickory, <a href="#Page_64">64</a></li>
+
+<li>Brown locust, <a href="#Page_66">66</a></li>
+
+<li>Buckeye, <a href="#Page_45">45</a></li>
+
+<li>Buckeye, fetid, <a href="#Page_45">45</a></li>
+
+<li>Buckeye, Ohio, <a href="#Page_45">45</a></li>
+
+<li>Buckeye, sweet, <a href="#Page_45">45</a></li>
+
+<li>Buckthorne, <a href="#Page_45">45</a></li>
+
+<li>Bud hickory, big, <a href="#Page_64">64</a></li>
+
+<li>Bull nut hickory, <a href="#Page_64">64</a></li>
+
+<li>Bull pine, <a href="#Page_25">25</a></li>
+
+<li>Bur oak, <a href="#Page_72">72</a></li>
+
+<li>Burning bush, <a href="#Page_82">82</a></li>
+
+<li>Bush, burning, <a href="#Page_82">82</a></li>
+
+<li>Bush, juniper, <a href="#Page_18">18</a></li>
+
+<li>Butternut, <a href="#Page_45">45</a></li>
+
+<li>Button ball tree, <a href="#Page_80">80</a></li>
+
+<li>Button wood, <a href="#Page_80">80</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">California Redwood</span>, <a href="#Page_19">19</a></li>
+
+<li>California white pine, <a href="#Page_25">25</a></li>
+
+<li>Canadian pine, <a href="#Page_25">25</a></li>
+
+<li>Canary wood, <a href="#Page_81">81</a></li>
+
+<li>Canoe birch, <a href="#Page_43">43</a></li>
+
+<li>Canoe cedar, <a href="#Page_17">17</a></li>
+
+<li>Carolina ash, <a href="#Page_39">39</a></li>
+
+<li>Carolina pine, <a href="#Page_26">26</a></li>
+
+<li>Carolina poplar, <a href="#Page_77">77</a></li>
+
+<li>Cars, method of loading kiln, <a href="#Page_206">206</a></li>
+
+<li>Catalpa, <a href="#Page_46">46</a></li>
+
+<li>Cedar, <a href="#Page_17">17</a></li>
+
+<li>Cedar, Alaska, <a href="#Page_18">18</a></li>
+
+<li>Cedar, canoe, <a href="#Page_17">17</a></li>
+
+<li>Cedar, elm, <a href="#Page_51">51</a></li>
+
+<li>Cedar, ground, <a href="#Page_19">19</a></li>
+
+<li>Cedar, incense, <a href="#Page_18">18</a></li>
+
+<li>Cedar of the West, red, <a href="#Page_17">17</a></li>
+
+<li>Cedar, Oregon, <a href="#Page_18">18</a></li>
+
+<li>Cedar, pencil, <a href="#Page_18">18</a></li>
+
+<li>Cedar, Port Orford, <a href="#Page_18">18</a></li>
+
+<li>Cedar, red, <a href="#Page_18">18</a>, <a href="#Page_19">19</a></li>
+
+<li>Cedar, white, <a href="#Page_17">17</a>, <a href="#Page_18">18</a></li>
+
+<li>Cedar, yellow, <a href="#Page_18">18</a></li>
+
+<li>Changes rendering drying difficult, <a href="#Page_140">140</a></li>
+
+<li>Characteristics and properties of wood, <a href="#Page_1">1</a></li>
+
+<li>Checking and splitting, prevention of, <a href="#Page_129">129</a></li>
+
+<li>Cherry, <a href="#Page_47">47</a></li>
+
+<li>Cherry birch, <a href="#Page_41">41</a><span class='pagenum'><a name="Page_264" id="Page_264">[264]</a></span></li>
+
+<li>Cherry, bird, <a href="#Page_47">47</a></li>
+
+<li>Cherry, black, <a href="#Page_47">47</a></li>
+
+<li>Cherry, Indian, <a href="#Page_45">45</a></li>
+
+<li>Cherry, red, <a href="#Page_47">47</a></li>
+
+<li>Cherry, rum, <a href="#Page_47">47</a></li>
+
+<li>Cherry, wild, <a href="#Page_47">47</a></li>
+
+<li>Cherry, wild red, <a href="#Page_47">47</a></li>
+
+<li>Chestnut, <a href="#Page_48">48</a></li>
+
+<li>Chestnut, horse, <a href="#Page_45">45</a>, <a href="#Page_65">65</a></li>
+
+<li>Chestnut oak, <a href="#Page_73">73</a></li>
+
+<li>Chestnut oak, rock, <a href="#Page_73">73</a></li>
+
+<li>Chestnut oak, scrub, <a href="#Page_74">74</a></li>
+
+<li>Chinquapin, <a href="#Page_48">48</a>, <a href="#Page_49">49</a></li>
+
+<li>Chinquapin oak, <a href="#Page_73">73</a>, <a href="#Page_74">74</a></li>
+
+<li>Chinquapin oak, dwarf, <a href="#Page_74">74</a></li>
+
+<li>Choice of drying method, <a href="#Page_195">195</a></li>
+
+<li>Circassian walnut, <a href="#Page_60">60</a></li>
+
+<li>Circulation, air, <a href="#Page_173">173</a></li>
+
+<li>Clammy locust, <a href="#Page_66">66</a></li>
+
+<li>Classes of trees, <a href="#Page_5">5</a></li>
+
+<li>Cliff elm, <a href="#Page_50">50</a></li>
+
+<li>Coast redwood, <a href="#Page_19">19</a></li>
+
+<li>Coffee nut, <a href="#Page_49">49</a></li>
+
+<li>Coffee tree, <a href="#Page_49">49</a></li>
+
+<li>Color and odor of wood, <a href="#Page_89">89</a></li>
+
+<li>Color, odor, weight, and figure in wood, grain, <a href="#Page_86">86</a></li>
+
+<li>Composition of sap, <a href="#Page_116">116</a></li>
+
+<li>Conditions and species, temperature depends on, <a href="#Page_171">171</a></li>
+
+<li>Conditions favorable for insect injury, <a href="#Page_106">106</a></li>
+
+<li>Conditions governing the drying of wood, <a href="#Page_156">156</a></li>
+
+<li>Conditions of success in kiln-drying, <a href="#Page_169">169</a></li>
+
+<li>Coniferous trees, <a href="#Page_8">8</a></li>
+
+<li>Coniferous trees, wood of, <a href="#Page_8">8</a></li>
+
+<li>Coniferous woods, list of important, <a href="#Page_17">17</a></li>
+
+<li>Containing alcoholic liquids, staves and heads of barrels, <a href="#Page_112">112</a></li>
+
+<li>Cooperage stock and wooden truss hoops, dry, <a href="#Page_112">112</a></li>
+
+<li>Cork elm, <a href="#Page_50">50</a></li>
+
+<li>Cotton gum, <a href="#Page_60">60</a></li>
+
+<li>Cottonwood, <a href="#Page_49">49</a>, <a href="#Page_77">77</a>, <a href="#Page_78">78</a></li>
+
+<li>Cottonwood, black, <a href="#Page_78">78</a></li>
+
+<li>Cottonwood, swamp, <a href="#Page_78">78</a></li>
+
+<li>Cow oak, <a href="#Page_74">74</a></li>
+
+<li>Crab apple, <a href="#Page_49">49</a></li>
+
+<li>Crab, fragrant, <a href="#Page_49">49</a></li>
+
+<li>Crack willow, <a href="#Page_84">84</a></li>
+
+<li>Crude products, <a href="#Page_106">106</a></li>
+
+<li>Cuban pine, <a href="#Page_26">26</a></li>
+
+<li>Cucumber tree, <a href="#Page_49">49</a>, <a href="#Page_67">67</a></li>
+
+<li>Cup oak, mossy, <a href="#Page_72">72</a></li>
+
+<li>Cup oak, over-, <a href="#Page_72">72</a>, <a href="#Page_73">73</a></li>
+
+<li>Custard apple, <a href="#Page_76">76</a></li>
+
+<li>Cypress, <a href="#Page_19">19</a></li>
+
+<li>Cypress, Alaska, <a href="#Page_18">18</a></li>
+
+<li>Cypress, bald, <a href="#Page_19">19</a></li>
+
+<li>Cypress, black, <a href="#Page_19">19</a></li>
+
+<li>Cypress, Lawson's, <a href="#Page_18">18</a></li>
+
+<li>Cypress, pecky, <a href="#Page_19">19</a></li>
+
+<li>Cypress, red, <a href="#Page_19">19</a></li>
+
+<li>Cypress, white, <a href="#Page_19">19</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">D'Arc, Bois</span>, <a href="#Page_45">45</a>, <a href="#Page_76">76</a></li>
+
+<li>Deal, yellow, <a href="#Page_23">23</a></li>
+
+<li>Demands upon soil and moisture of red gum, <a href="#Page_56">56</a></li>
+
+<li>Depends on conditions and species, temperature, <a href="#Page_171">171</a></li>
+
+<li>Description of the forest service kiln, theory and, <a href="#Page_161">161</a></li>
+
+<li>Diagram, the uses of the humidity, <a href="#Page_237">237</a></li>
+
+<li>Difference between seasoned and unseasoned wood, <a href="#Page_121">121</a></li>
+
+<li>Different grains of wood, <a href="#Page_86">86</a></li>
+
+<li>Different kiln-drying according to species, <a href="#Page_170">170</a></li>
+
+<li>Different species, weight of kiln-dried wood of, <a href="#Page_95">95</a></li>
+
+<li>Different types, kilns of, <a href="#Page_196">196</a></li>
+
+<li>Different types of dry kilns, <a href="#Page_185">185</a></li>
+
+<li>Different types of kiln doors, <a href="#Page_231">231</a></li>
+
+<li>Difficult, changes rendering drying, <a href="#Page_140">140</a></li>
+
+<li>Difficulties of drying wood, <a href="#Page_138">138</a></li>
+
+<li>Distribution of water in wood, <a href="#Page_114">114</a></li>
+
+<li>Distribution of water in wood, local, <a href="#Page_114">114</a></li>
+
+<li>Distribution of water in wood seasonal, <a href="#Page_115">115</a></li>
+
+<li>Dogwood, <a href="#Page_49">49</a></li>
+
+<li>Doors, different types of kiln, <a href="#Page_231">231</a></li>
+
+<li>Douglas spruce, <a href="#Page_29">29</a></li>
+
+<li>Downy linden, <a href="#Page_39">39</a></li>
+
+<li>Downy poplar, <a href="#Page_78">78</a></li>
+
+<li>Dry cooperage stock and wooden truss hoops, <a href="#Page_112">112</a></li>
+
+<li>Drying according to species, different kiln, <a href="#Page_170">170</a></li>
+
+<li>Drying, advantages of kiln-drying over air, <a href="#Page_156">156</a><span class='pagenum'><a name="Page_265" id="Page_265">[265]</a></span></li>
+
+<li>Drying at atmospheric pressure, <a href="#Page_146">146</a></li>
+
+<li>Drying by superheated steam, <a href="#Page_150">150</a></li>
+
+<li>Drying, conditions of success in kiln, <a href="#Page_169">169</a></li>
+
+<li>Drying difficult, changes rendering, <a href="#Page_140">140</a></li>
+
+<li>Drying gum, kiln, <a href="#Page_180">180</a></li>
+
+<li>Drying, helpful appliances in kiln, <a href="#Page_237">237</a></li>
+
+<li>Drying, kiln, <a href="#Page_164">164</a>, <a href="#Page_177">177</a></li>
+
+<li>Drying, losses due to improper kiln, <a href="#Page_141">141</a></li>
+
+<li>Drying method, choice of, <a href="#Page_185">185</a></li>
+
+<li>Drying, methods of kiln, <a href="#Page_145">145</a></li>
+
+<li>Drying, objects of kiln, <a href="#Page_168">168</a></li>
+
+<li>Drying of green red gum, kiln, <a href="#Page_183">183</a></li>
+
+<li>Drying of wood, kiln, <a href="#Page_156">156</a></li>
+
+<li>Drying of wood, physical conditions governing the, <a href="#Page_156">156</a></li>
+
+<li>Drying, physical properties that influence, <a href="#Page_125">125</a></li>
+
+<li>Drying, properties of wood that effect, <a href="#Page_141">141</a></li>
+
+<li>Drying, theory of kiln, <a href="#Page_157">157</a></li>
+
+<li>Drying, underlying principles of kiln, <a href="#Page_166">166</a></li>
+
+<li>Drying under pressure and vacuum, <a href="#Page_146">146</a></li>
+
+<li>Drying, unsolved problems in kiln, <a href="#Page_143">143</a></li>
+
+<li>Drying wood, difficulties of, <a href="#Page_138">138</a></li>
+
+<li>Drying 100 lb. of green wood in the kiln, pounds of water lost, <a href="#Page_179">179</a></li>
+
+<li>Dry kiln, apartment, <a href="#Page_198">198</a></li>
+
+<li>Dry kiln, box, <a href="#Page_204">204</a></li>
+
+<li>Dry kiln, operation of the blower, <a href="#Page_186">186</a></li>
+
+<li>Dry kiln, operation of the moist-air, <a href="#Page_192">192</a></li>
+
+<li>Dry kiln, moist-air or pipe, <a href="#Page_188">188</a></li>
+
+<li>Dry kiln, pocket, <a href="#Page_200">200</a></li>
+
+<li>Dry kiln, progressive, <a href="#Page_196">196</a></li>
+
+<li>Dry kiln, requirements in a satisfactory, <a href="#Page_160">160</a></li>
+
+<li>Dry kilns, different types of, <a href="#Page_185">185</a></li>
+
+<li>Dry kiln specialties, <a href="#Page_206">206</a></li>
+
+<li>Dry kilns, types of, <a href="#Page_185">185</a></li>
+
+<li>Dry kiln, tower, <a href="#Page_202">202</a></li>
+
+<li>Dry wood, absorption of water by, <a href="#Page_124">124</a></li>
+
+<li>Duck oak, <a href="#Page_73">73</a></li>
+
+<li>Due to improper kiln-drying, losses, <a href="#Page_141">141</a></li>
+
+<li>Dwarf chinquapin oak, <a href="#Page_74">74</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Effects of Moisture on Wood</span>, <a href="#Page_117">117</a></li>
+
+<li>Elder, box, <a href="#Page_69">69</a></li>
+
+<li>Electric heater, the, <a href="#Page_250">250</a></li>
+
+<li>Elimination of stain and mildew, <a href="#Page_136">136</a></li>
+
+<li>Elm, <a href="#Page_50">50</a></li>
+
+<li>Elm, American, <a href="#Page_50">50</a></li>
+
+<li>Elm, cedar, <a href="#Page_51">51</a></li>
+
+<li>Elm, cliff, <a href="#Page_50">50</a></li>
+
+<li>Elm, cork, <a href="#Page_50">50</a></li>
+
+<li>Elm, hickory, <a href="#Page_50">50</a></li>
+
+<li>Elm, moose, <a href="#Page_51">51</a></li>
+
+<li>Elm, red, <a href="#Page_51">51</a></li>
+
+<li>Elm, rock, <a href="#Page_50">50</a></li>
+
+<li>Elm, slippery, <a href="#Page_51">51</a></li>
+
+<li>Elm, water, <a href="#Page_50">50</a></li>
+
+<li>Elm, winged, <a href="#Page_51">51</a></li>
+
+<li>Elm, white, <a href="#Page_50">50</a></li>
+
+<li>Enemies of wood, <a href="#Page_98">98</a></li>
+
+<li>Evaporation of water, manner of, <a href="#Page_123">123</a></li>
+
+<li>Evaporation, rapidity of, <a href="#Page_124">124</a></li>
+
+<li>Expansion of wood, <a href="#Page_135">135</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Factories, Scalometer in</span>, <a href="#Page_249">249</a></li>
+
+<li>False acacia, <a href="#Page_66">66</a></li>
+
+<li>Favorable for insect injury, conditions, <a href="#Page_106">106</a></li>
+
+<li>Fetid buckeye, <a href="#Page_45">45</a></li>
+
+<li>Fibre saturation point in wood, <a href="#Page_118">118</a></li>
+
+<li>Field birch, old, <a href="#Page_42">42</a></li>
+
+<li>Field pine, old, <a href="#Page_25">25</a>, <a href="#Page_26">26</a></li>
+
+<li>Figure in wood, <a href="#Page_96">96</a></li>
+
+<li>Figure in wood, grain, color, odor, weight, and, <a href="#Page_86">86</a></li>
+
+<li>Final steaming of gum, <a href="#Page_182">182</a></li>
+
+<li>Fir, <a href="#Page_20">20</a></li>
+
+<li>Fir, balm of gilead, <a href="#Page_20">20</a></li>
+
+<li>Fir balsam, <a href="#Page_20">20</a></li>
+
+<li>Fir, noble, <a href="#Page_21">21</a></li>
+
+<li>Fir, red, <a href="#Page_21">21</a>, <a href="#Page_29">29</a></li>
+
+<li>Fir tree, <a href="#Page_20">20</a></li>
+
+<li>Fir, white, <a href="#Page_20">20</a>, <a href="#Page_21">21</a></li>
+
+<li>Fir, yellow, <a href="#Page_29">29</a></li>
+
+<li>Flat-headed borers, <a href="#Page_103">103</a></li>
+
+<li>Forest service kiln, theory and description of, <a href="#Page_161">161</a></li>
+
+<li>Form of the red gum, <a href="#Page_55">55</a></li>
+
+<li>Fragrant crab, <a href="#Page_49">49</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Gauge, the Recording Steam</span>, <a href="#Page_246">246</a></li>
+
+<li>Georgia pine, <a href="#Page_24">24</a></li>
+
+<li>Gilead, balm of, <a href="#Page_79">79</a></li>
+
+<li>Gilead fir, balm of, <a href="#Page_20">20</a><span class='pagenum'><a name="Page_266" id="Page_266">[266]</a></span></li>
+
+<li>Ginger pine, <a href="#Page_18">18</a></li>
+
+<li>Glaucous willow, <a href="#Page_84">84</a></li>
+
+<li>Governing the drying of wood, physical conditions, <a href="#Page_156">156</a></li>
+
+<li>Grain, color, odor, weight, and figure in wood, <a href="#Page_86">86</a></li>
+
+<li>Grains of wood, different, <a href="#Page_86">86</a></li>
+
+<li>Gray birch, <a href="#Page_42">42</a></li>
+
+<li>Gray pine, <a href="#Page_27">27</a></li>
+
+<li>Green ash, <a href="#Page_38">38</a></li>
+
+<li>Green red gum, kiln-drying, <a href="#Page_183">183</a></li>
+
+<li>Green wood in the kiln, pounds of water lost in drying 100 lbs., <a href="#Page_179">179</a></li>
+
+<li>Ground ash, <a href="#Page_38">38</a></li>
+
+<li>Ground cedar, <a href="#Page_19">19</a></li>
+
+<li>Growth red gum, second, <a href="#Page_59">59</a></li>
+
+<li>Gum, <a href="#Page_52">52</a></li>
+
+<li>Gum, black, <a href="#Page_62">62</a></li>
+
+<li>Gum, cotton, <a href="#Page_60">60</a></li>
+
+<li>Gum, demands upon soil and moisture of red, <a href="#Page_56">56</a></li>
+
+<li>Gum, final steaming of, <a href="#Page_182">182</a></li>
+
+<li>Gum, form of red, <a href="#Page_55">55</a></li>
+
+<li>Gum, kiln-drying, <a href="#Page_180">180</a></li>
+
+<li>Gum, kiln-drying of green red, <a href="#Page_183">183</a></li>
+
+<li>Gum, method of piling, <a href="#Page_180">180</a></li>
+
+<li>Gum, preliminary steaming of, <a href="#Page_182">182</a></li>
+
+<li>Gum, range of red, <a href="#Page_55">55</a></li>
+
+<li>Gum, range of tupelo, <a href="#Page_61">61</a></li>
+
+<li>Gum, red, <a href="#Page_54">54</a>, <a href="#Page_79">79</a></li>
+
+<li>Gum, reproduction of red, <a href="#Page_57">57</a></li>
+
+<li>Gum, second-growth red, <a href="#Page_59">59</a></li>
+
+<li>Gum, sour, <a href="#Page_62">62</a>, <a href="#Page_80">80</a></li>
+
+<li>Gum, sweet, <a href="#Page_54">54</a>, <a href="#Page_80">80</a></li>
+
+<li>Gum, tolerance of the red, <a href="#Page_56">56</a></li>
+
+<li>Gum, tupelo, <a href="#Page_60">60</a></li>
+
+<li>Gum, uses of tupelo, <a href="#Page_61">61</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Hackberry</span>, <a href="#Page_62">62</a></li>
+
+<li>Hacmatac, <a href="#Page_22">22</a></li>
+
+<li>Hard maple, <a href="#Page_68">68</a></li>
+
+<li>Hard pine, <a href="#Page_26">26</a></li>
+
+<li>Hard pines, <a href="#Page_24">24</a></li>
+
+<li>Hard pine, southern, <a href="#Page_24">24</a></li>
+
+<li>Hardwoods, <a href="#Page_37">37</a></li>
+
+<li>Hazel pine, <a href="#Page_54">54</a>, <a href="#Page_60">60</a></li>
+
+<li>Headed borers, flat, <a href="#Page_103">103</a></li>
+
+<li>Headed borers, round, <a href="#Page_101">101</a></li>
+
+<li>Heading, stave and shingle bolts, <a href="#Page_109">109</a></li>
+
+<li>Heads and staves of barrels containing alcoholic liquids, <a href="#Page_112">112</a></li>
+
+<li>Heart hickory, white, <a href="#Page_64">64</a></li>
+
+<li>Heartwood, sap and, <a href="#Page_8">8</a></li>
+
+<li>Heater, the electric, <a href="#Page_250">250</a></li>
+
+<li>Helpful appliances in kiln-drying, <a href="#Page_237">237</a></li>
+
+<li>Hemlock, <a href="#Page_21">21</a></li>
+
+<li>Hemlock spruce, <a href="#Page_21">21</a></li>
+
+<li>Hickory, <a href="#Page_63">63</a></li>
+
+<li>Hickory, big bud, <a href="#Page_64">64</a></li>
+
+<li>Hickory, bitternut, <a href="#Page_64">64</a></li>
+
+<li>Hickory, black, <a href="#Page_64">64</a></li>
+
+<li>Hickory, black nut, <a href="#Page_64">64</a></li>
+
+<li>Hickory, brown, <a href="#Page_64">64</a></li>
+
+<li>Hickory, bull nut, <a href="#Page_64">64</a></li>
+
+<li>Hickory elm, <a href="#Page_50">50</a></li>
+
+<li>Hickory, mockernut, <a href="#Page_64">64</a></li>
+
+<li>Hickory, pignut, <a href="#Page_64">64</a></li>
+
+<li>Hickory, poplar, <a href="#Page_81">81</a></li>
+
+<li>Hickory, scalybark, <a href="#Page_64">64</a></li>
+
+<li>Hickory, shagbark, <a href="#Page_64">64</a></li>
+
+<li>Hickory, shellbark, <a href="#Page_64">64</a></li>
+
+<li>Hickory, swamp, <a href="#Page_64">64</a></li>
+
+<li>Hickory, switchbud, <a href="#Page_64">64</a></li>
+
+<li>Hickory, white heart, <a href="#Page_64">64</a></li>
+
+<li>Holly, <a href="#Page_64">64</a>, <a href="#Page_65">65</a></li>
+
+<li>Holly, mountain, <a href="#Page_65">65</a></li>
+
+<li>Honey locust, <a href="#Page_66">66</a></li>
+
+<li>Honey shucks, <a href="#Page_66">66</a></li>
+
+<li>Hoop ash, <a href="#Page_38">38</a></li>
+
+<li>Hoops, dry cooperage stock and wooden truss, <a href="#Page_112">112</a></li>
+
+<li>Hop hornbeam, <a href="#Page_65">65</a></li>
+
+<li>Hornbeam, <a href="#Page_44">44</a></li>
+
+<li>Hornbeam, hop, <a href="#Page_65">65</a></li>
+
+<li>Horse chestnut, <a href="#Page_45">45</a>, <a href="#Page_65">65</a></li>
+
+<li>Hot blast or blower kiln, <a href="#Page_185">185</a></li>
+
+<li>Humidity, <a href="#Page_174">174</a></li>
+
+<li>Humidity diagram, uses of the, <a href="#Page_237">237</a></li>
+
+<li>How to prevent insect injury, <a href="#Page_107">107</a></li>
+
+<li>How wood is seasoned, <a href="#Page_145">145</a></li>
+
+<li>Hygrodeik, the, <a href="#Page_242">242</a></li>
+
+<li>Hygrometer, the recording, <a href="#Page_242">242</a></li>
+
+<li>Hygrometer, the registering, <a href="#Page_244">244</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Illinois Nut</span>, <a href="#Page_64">64</a></li>
+
+<li>Important broad-leaved trees, list of most, <a href="#Page_37">37</a></li>
+
+<li>Important coniferous woods, list of, <a href="#Page_17">17</a></li>
+
+<li>Impregnation methods, <a href="#Page_151">151</a></li>
+
+<li>Improper kiln-drying, losses due to, <a href="#Page_141">141</a></li>
+
+<li>Incense cedar, <a href="#Page_18">18</a></li>
+
+<li>Indian bean, <a href="#Page_46">46</a></li>
+
+<li>Indian cherry, <a href="#Page_45">45</a><span class='pagenum'><a name="Page_267" id="Page_267">[267]</a></span></li>
+
+<li>Influence drying, physical properties that, <a href="#Page_125">125</a></li>
+
+<li>Injury, conditions favorable for insect, <a href="#Page_106">106</a></li>
+
+<li>Injury from insects, how to prevent, <a href="#Page_107">107</a></li>
+
+<li>Insect injury, conditions favorable for, <a href="#Page_106">106</a></li>
+
+<li>Insects, how to prevent injury from, <a href="#Page_107">107</a></li>
+
+<li>Iron oak, <a href="#Page_74">74</a></li>
+
+<li>Ironwood, <a href="#Page_44">44</a>, <a href="#Page_65">65</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Jack, Black</span>, <a href="#Page_75">75</a></li>
+
+<li>Jack oak, <a href="#Page_75">75</a></li>
+
+<li>Jack pine, <a href="#Page_27">27</a></li>
+
+<li>Jersey pine, <a href="#Page_27">27</a></li>
+
+<li>Juniper, <a href="#Page_18">18</a></li>
+
+<li>Juniper bush, <a href="#Page_18">18</a></li>
+
+<li>Juniper, red, <a href="#Page_18">18</a></li>
+
+<li>Juniper, savin, <a href="#Page_18">18</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Keep Records of the Moisture Content</span>, <a href="#Page_249">249</a></li>
+
+<li>Kiln, apartment dry, <a href="#Page_198">198</a></li>
+
+<li>Kiln, blower or hot blast, <a href="#Page_185">185</a></li>
+
+<li>Kiln, box dry, <a href="#Page_204">204</a></li>
+
+<li>Kiln cars and method of loading, <a href="#Page_206">206</a></li>
+
+<li>Kiln doors, different types, <a href="#Page_231">231</a></li>
+
+<li>Kiln-dried wood of different species, weight of, <a href="#Page_95">95</a></li>
+
+<li>Kiln-drying, <a href="#Page_164">164</a>, <a href="#Page_177">177</a></li>
+
+<li>Kiln-drying according to species, different, <a href="#Page_170">170</a></li>
+
+<li>Kiln-drying, conditions of success in, <a href="#Page_169">169</a></li>
+
+<li>Kiln-drying gum, <a href="#Page_180">180</a></li>
+
+<li>Kiln-drying, helpful appliances in, <a href="#Page_237">237</a></li>
+
+<li>Kiln-drying, losses due to improper, <a href="#Page_141">141</a></li>
+
+<li>Kiln-drying, objects of, <a href="#Page_168">168</a></li>
+
+<li>Kiln-drying of green red gum, <a href="#Page_183">183</a></li>
+
+<li>Kiln-drying of wood, <a href="#Page_156">156</a></li>
+
+<li>Kiln-drying of wood, <a href="#Page_156">156</a></li>
+
+<li>Kiln-drying over air-drying, advantages of, <a href="#Page_156">156</a></li>
+
+<li>Kiln-drying, theory of, <a href="#Page_157">157</a></li>
+
+<li>Kiln-drying, underlying principles of, <a href="#Page_166">166</a></li>
+
+<li>Kiln-drying, unsolved problems in, <a href="#Page_143">143</a></li>
+
+<li>Kiln, operation of the blower dry, <a href="#Page_186">186</a></li>
+
+<li>Kiln, operation of the moist-air dry, <a href="#Page_192">192</a></li>
+
+<li>Kiln, pipe or moist-air dry, <a href="#Page_188">188</a></li>
+
+<li>Kiln, pocket dry, <a href="#Page_200">200</a></li>
+
+<li>Kiln, progressive dry, <a href="#Page_196">196</a></li>
+
+<li>Kiln, requirements in a satisfactory dry, <a href="#Page_160">160</a></li>
+
+<li>Kilns, different types of dry, <a href="#Page_185">185</a></li>
+
+<li>Kilns of different types, <a href="#Page_196">196</a></li>
+
+<li>Kiln specialties, dry, <a href="#Page_206">206</a></li>
+
+<li>Kiln, theory and description of the forest service, <a href="#Page_161">161</a></li>
+
+<li>Kilns, types of dry, <a href="#Page_185">185</a></li>
+
+<li>Kiln, tower dry, <a href="#Page_202">202</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Land Spruce, Tide</span>, <a href="#Page_28">28</a></li>
+
+<li>Larch, <a href="#Page_22">22</a></li>
+
+<li>Larch, American, <a href="#Page_22">22</a></li>
+
+<li>Larch, black, <a href="#Page_22">22</a></li>
+
+<li>Larch, western, <a href="#Page_22">22</a></li>
+
+<li>Large-toothed aspen, <a href="#Page_79">79</a></li>
+
+<li>Laurel, <a href="#Page_65">65</a></li>
+
+<li>Laurel oak, <a href="#Page_75">75</a></li>
+
+<li>Lawson's cypress, <a href="#Page_18">18</a></li>
+
+<li>Leaf pine, long-, <a href="#Page_24">24</a></li>
+
+<li>Leaf pine, short-, <a href="#Page_26">26</a></li>
+
+<li>Leaf willow, long, <a href="#Page_84">84</a></li>
+
+<li>Leaved basswood, small, <a href="#Page_39">39</a></li>
+
+<li>Leaved birch, aspen, <a href="#Page_42">42</a></li>
+
+<li>Leaved maple, ash, <a href="#Page_69">69</a></li>
+
+<li>Leaved maple, broad, <a href="#Page_69">69</a></li>
+
+<li>Leaved maple, silver, <a href="#Page_69">69</a></li>
+
+<li>Leaved trees, broad, <a href="#Page_31">31</a></li>
+
+<li>Leaved trees, list of most important broad, <a href="#Page_37">37</a></li>
+
+<li>Leaved trees, wood of broad, <a href="#Page_31">31</a></li>
+
+<li>Leverwood, <a href="#Page_65">65</a></li>
+
+<li>Life, tree of, <a href="#Page_17">17</a></li>
+
+<li>Lime tree, <a href="#Page_39">39</a></li>
+
+<li>Lin, <a href="#Page_39">39</a></li>
+
+<li>Linden, <a href="#Page_39">39</a></li>
+
+<li>Linden, American, <a href="#Page_39">39</a></li>
+
+<li>Linden, downy, <a href="#Page_39">39</a></li>
+
+<li>Liquidamber, <a href="#Page_54">54</a></li>
+
+<li>Liquids, staves and heads of barrels containing alcoholic, <a href="#Page_112">112</a></li>
+
+<li>List of important coniferous trees, <a href="#Page_17">17</a></li>
+
+<li>List of most important broad-leaved trees, <a href="#Page_37">37</a></li>
+
+<li>Live oak, <a href="#Page_75">75</a>, <a href="#Page_76">76</a></li>
+
+<li>Loading, kiln cars and method of, <a href="#Page_206">206</a></li>
+
+<li>Loblolly pine, <a href="#Page_25">25</a><span class='pagenum'><a name="Page_268" id="Page_268">[268]</a></span></li>
+
+<li>Local distribution of water in wood, <a href="#Page_114">114</a></li>
+
+<li>Locust, <a href="#Page_66">66</a></li>
+
+<li>Locust, black, <a href="#Page_66">66</a></li>
+
+<li>Locust, brown, <a href="#Page_66">66</a></li>
+
+<li>Locust, clammy, <a href="#Page_66">66</a></li>
+
+<li>Locust, honey, <a href="#Page_66">66</a></li>
+
+<li>Locust, sweet, <a href="#Page_66">66</a></li>
+
+<li>Locust, yellow, <a href="#Page_66">66</a></li>
+
+<li>Lodge-pole pine, <a href="#Page_27">27</a></li>
+
+<li>Lombardy poplar, <a href="#Page_79">79</a></li>
+
+<li>Long-leaf pine, <a href="#Page_24">24</a></li>
+
+<li>Long-leaf willow, <a href="#Page_84">84</a></li>
+
+<li>Long-straw pine, <a href="#Page_24">24</a></li>
+
+<li>Losses due to improper kiln-drying, <a href="#Page_141">141</a></li>
+
+<li>Lost in kiln-drying 100 lb. green wood in the kiln, pounds of water, <a href="#Page_179">179</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Magnolia</span>, <a href="#Page_67">67</a></li>
+
+<li>Magnolia, small, <a href="#Page_67">67</a></li>
+
+<li>Magnolia, swamp, <a href="#Page_67">67</a></li>
+
+<li>Mahogany, birch, <a href="#Page_41">41</a></li>
+
+<li>Mahogany, white, <a href="#Page_45">45</a></li>
+
+<li>Manner of evaporation of water, <a href="#Page_123">123</a></li>
+
+<li>Maple, <a href="#Page_67">67</a></li>
+
+<li>Maple, ash-leaved, <a href="#Page_69">69</a></li>
+
+<li>Maple, broad-leaved, <a href="#Page_69">69</a></li>
+
+<li>Maple, hard, <a href="#Page_68">68</a></li>
+
+<li>Maple, mountain, <a href="#Page_69">69</a></li>
+
+<li>Maple, Oregon, <a href="#Page_69">69</a></li>
+
+<li>Maple, red, <a href="#Page_69">69</a></li>
+
+<li>Maple, rock, <a href="#Page_68">68</a></li>
+
+<li>Maple, silver, <a href="#Page_69">69</a></li>
+
+<li>Maple, silver-leaved, <a href="#Page_69">69</a></li>
+
+<li>Maple, soft, <a href="#Page_69">69</a></li>
+
+<li>Maple, striped, <a href="#Page_70">70</a></li>
+
+<li>Maple, sugar, <a href="#Page_68">68</a></li>
+
+<li>Maple, swamp, <a href="#Page_69">69</a></li>
+
+<li>Maple, water, <a href="#Page_69">69</a></li>
+
+<li>Maple, white, <a href="#Page_69">69</a></li>
+
+<li>Maul oak, <a href="#Page_75">75</a>, <a href="#Page_76">76</a></li>
+
+<li>Meadow pine, <a href="#Page_26">26</a></li>
+
+<li>Method, choice of drying, <a href="#Page_195">195</a></li>
+
+<li>Method of loading kiln cars, <a href="#Page_206">206</a></li>
+
+<li>Method of piling gum, <a href="#Page_180">180</a></li>
+
+<li>Methods, impregnation, <a href="#Page_151">151</a></li>
+
+<li>Methods of drying, <a href="#Page_154">154</a></li>
+
+<li>Mildew, elimination of stain and, <a href="#Page_136">136</a></li>
+
+<li>Minute structure, <a href="#Page_34">34</a></li>
+
+<li>Mockernut hickory, <a href="#Page_64">64</a></li>
+
+<li>Moist-air dry kiln, operation of, <a href="#Page_192">192</a></li>
+
+<li>Moist-air or pipe kiln, the, <a href="#Page_188">188</a></li>
+
+<li>Moisture content, keep records of the, <a href="#Page_249">249</a></li>
+
+<li>Moisture, demands upon soil and, <a href="#Page_56">56</a></li>
+
+<li>Moisture on wood, effects of, <a href="#Page_117">117</a></li>
+
+<li>Moose elm, <a href="#Page_51">51</a></li>
+
+<li>Moose-wood, <a href="#Page_70">70</a></li>
+
+<li>Mossy-cup oak, <a href="#Page_72">72</a></li>
+
+<li>Most important broad-leaved trees list of, <a href="#Page_37">37</a></li>
+
+<li>Mountain holly, <a href="#Page_65">65</a></li>
+
+<li>Mountain maple, <a href="#Page_69">69</a></li>
+
+<li>Mulberry, <a href="#Page_70">70</a></li>
+
+<li>Mulberry, red, <a href="#Page_70">70</a></li>
+
+<li>Myrtle, <a href="#Page_65">65</a>, <a href="#Page_70">70</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Nettle Tree</span>, <a href="#Page_62">62</a></li>
+
+<li>Noble fir, <a href="#Page_21">21</a></li>
+
+<li>Norway pine, <a href="#Page_25">25</a></li>
+
+<li>Nut, coffee, <a href="#Page_49">49</a></li>
+
+<li>Nut hickory, black, <a href="#Page_64">64</a></li>
+
+<li>Nut hickory, bull, <a href="#Page_64">64</a></li>
+
+<li>Nut, Illinois, <a href="#Page_64">64</a></li>
+
+<li>Nyssa, <a href="#Page_60">60</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Oak</span>, <a href="#Page_70">70</a></li>
+
+<li>Oak, American, <a href="#Page_71">71</a></li>
+
+<li>Oak, barren, <a href="#Page_75">75</a></li>
+
+<li>Oak, basket, <a href="#Page_74">74</a></li>
+
+<li>Oak, bear, <a href="#Page_74">74</a></li>
+
+<li>Oak, black, <a href="#Page_74">74</a></li>
+
+<li>Oak, bur, <a href="#Page_72">72</a></li>
+
+<li>Oak, chestnut, <a href="#Page_73">73</a></li>
+
+<li>Oak, chinquapin, <a href="#Page_73">73</a>, <a href="#Page_74">74</a></li>
+
+<li>Oak, cow, <a href="#Page_74">74</a></li>
+
+<li>Oak, duck, <a href="#Page_73">73</a></li>
+
+<li>Oak, dwarf chinquapin, <a href="#Page_74">74</a></li>
+
+<li>Oak, iron, <a href="#Page_74">74</a></li>
+
+<li>Oak, jack, <a href="#Page_75">75</a></li>
+
+<li>Oak, laurel, <a href="#Page_75">75</a></li>
+
+<li>Oak, live, <a href="#Page_75">75</a>, <a href="#Page_76">76</a></li>
+
+<li>Oak, maul, <a href="#Page_75">75</a>, <a href="#Page_76">76</a></li>
+
+<li>Oak, mossy-cup, <a href="#Page_72">72</a></li>
+
+<li>Oak, over-cup, <a href="#Page_72">72</a>, <a href="#Page_73">73</a></li>
+
+<li>Oak, peach, <a href="#Page_72">72</a></li>
+
+<li>Oak, pin, <a href="#Page_73">73</a></li>
+
+<li>Oak, possum, <a href="#Page_73">73</a></li>
+
+<li>Oak, post, <a href="#Page_74">74</a></li>
+
+<li>Oak, punk, <a href="#Page_73">73</a></li>
+
+<li>Oak, red, <a href="#Page_74">74</a>, <a href="#Page_75">75</a></li>
+
+<li>Oak, rock, <a href="#Page_73">73</a></li>
+
+<li>Oak, rock chestnut, <a href="#Page_73">73</a><span class='pagenum'><a name="Page_269" id="Page_269">[269]</a></span></li>
+
+<li>Oak, scarlet, <a href="#Page_75">75</a></li>
+
+<li>Oak, scrub, <a href="#Page_74">74</a></li>
+
+<li>Oak, scrub chestnut, <a href="#Page_74">74</a></li>
+
+<li>Oak, shingle, <a href="#Page_75">75</a></li>
+
+<li>Oak, Spanish, <a href="#Page_75">75</a></li>
+
+<li>Oak, swamp post, <a href="#Page_73">73</a></li>
+
+<li>Oak, swamp Spanish, <a href="#Page_73">73</a></li>
+
+<li>Oak, swamp white, <a href="#Page_72">72</a>, <a href="#Page_73">73</a></li>
+
+<li>Oak, water, <a href="#Page_73">73</a></li>
+
+<li>Oak, western white, <a href="#Page_71">71</a></li>
+
+<li>Oak, white, <a href="#Page_71">71</a>, <a href="#Page_72">72</a></li>
+
+<li>Oak, willow, <a href="#Page_72">72</a></li>
+
+<li>Oak, yellow, <a href="#Page_73">73</a>, <a href="#Page_74">74</a></li>
+
+<li>Oak, Valparaiso, <a href="#Page_76">76</a></li>
+
+<li>Objects of kiln-drying, <a href="#Page_168">168</a></li>
+
+<li>Odor and color of wood, <a href="#Page_89">89</a></li>
+
+<li>Odor, weight, and figure in wood, grain, color, <a href="#Page_86">86</a></li>
+
+<li>Ohio buckeye, <a href="#Page_45">45</a></li>
+
+<li>Old field birch, <a href="#Page_42">42</a></li>
+
+<li>Old field pine, <a href="#Page_25">25</a>, <a href="#Page_26">26</a></li>
+
+<li>Operation of the blower kiln, <a href="#Page_186">186</a></li>
+
+<li>Operation of the moist-air kiln, <a href="#Page_192">192</a></li>
+
+<li>Orange, osage, <a href="#Page_76">76</a></li>
+
+<li>Oregon ash, <a href="#Page_38">38</a></li>
+
+<li>Oregon cedar, <a href="#Page_18">18</a></li>
+
+<li>Oregon maple, <a href="#Page_69">69</a></li>
+
+<li>Oregon pine, <a href="#Page_29">29</a></li>
+
+<li>Orford cedar, Port, <a href="#Page_18">18</a></li>
+
+<li>Osage orange, <a href="#Page_76">76</a></li>
+
+<li>Out-of-door seasoning, <a href="#Page_154">154</a></li>
+
+<li>Over-cup oak, <a href="#Page_72">72</a>, <a href="#Page_73">73</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Papaw</span>, <a href="#Page_76">76</a></li>
+
+<li>Paper birch, <a href="#Page_43">43</a></li>
+
+<li>Peach oak, <a href="#Page_72">72</a></li>
+
+<li>Pecan, <a href="#Page_64">64</a></li>
+
+<li>Pecky cypress, <a href="#Page_19">19</a></li>
+
+<li>Pencil cedar, <a href="#Page_18">18</a></li>
+
+<li>Pepperidge, <a href="#Page_60">60</a></li>
+
+<li>Perch willow, <a href="#Page_84">84</a></li>
+
+<li>Persimmon, <a href="#Page_77">77</a></li>
+
+<li>Peruche, <a href="#Page_21">21</a></li>
+
+<li>Physical conditions governing the drying of wood, <a href="#Page_156">156</a></li>
+
+<li>Physical properties that influence drying, <a href="#Page_125">125</a></li>
+
+<li>Pignut hickory, <a href="#Page_64">64</a></li>
+
+<li>Piling gum, methods of, <a href="#Page_180">180</a></li>
+
+<li>Pine, American red, <a href="#Page_25">25</a></li>
+
+<li>Pine, bastard, <a href="#Page_26">26</a></li>
+
+<li>Pine, black, <a href="#Page_25">25</a>, <a href="#Page_27">27</a></li>
+
+<li>Pine, bull, <a href="#Page_25">25</a></li>
+
+<li>Pine, California white, <a href="#Page_25">25</a></li>
+
+<li>Pine, Canadian, <a href="#Page_25">25</a></li>
+
+<li>Pine, Carolina, <a href="#Page_26">26</a></li>
+
+<li>Pine, Cuban, <a href="#Page_26">26</a></li>
+
+<li>Pine, Georgia, <a href="#Page_24">24</a></li>
+
+<li>Pine, ginger, <a href="#Page_18">18</a></li>
+
+<li>Pine, gray, <a href="#Page_27">27</a></li>
+
+<li>Pine, hard, <a href="#Page_26">26</a></li>
+
+<li>Pine, hazel, <a href="#Page_54">54</a>, <a href="#Page_60">60</a></li>
+
+<li>Pine, jack, <a href="#Page_27">27</a></li>
+
+<li>Pine, Jersey, <a href="#Page_27">27</a></li>
+
+<li>Pine, loblolly, <a href="#Page_25">25</a></li>
+
+<li>Pine, lodge-pole, <a href="#Page_27">27</a></li>
+
+<li>Pine, long-leaf, <a href="#Page_24">24</a></li>
+
+<li>Pine, long-straw, <a href="#Page_24">24</a></li>
+
+<li>Pine, meadow, <a href="#Page_26">26</a></li>
+
+<li>Pine, Norway, <a href="#Page_25">25</a></li>
+
+<li>Pine, old field, <a href="#Page_25">25</a>, <a href="#Page_26">26</a></li>
+
+<li>Pine, Oregon, <a href="#Page_29">29</a></li>
+
+<li>Pine, pitch, <a href="#Page_26">26</a></li>
+
+<li>Pine, Puget Sound, <a href="#Page_29">29</a></li>
+
+<li>Pine, pumpkin, <a href="#Page_23">23</a>, <a href="#Page_24">24</a></li>
+
+<li>Pine, red, <a href="#Page_29">29</a></li>
+
+<li>Pine, rosemary, <a href="#Page_25">25</a></li>
+
+<li>Pine, sap, <a href="#Page_25">25</a></li>
+
+<li>Pine, scrub, <a href="#Page_27">27</a></li>
+
+<li>Pines, hard, <a href="#Page_24">24</a></li>
+
+<li>Pine, short-leaf, <a href="#Page_26">26</a></li>
+
+<li>Pine, short-straw, <a href="#Page_25">25</a></li>
+
+<li>Pine, slash, <a href="#Page_25">25</a>, <a href="#Page_26">26</a></li>
+
+<li>Pine, soft, <a href="#Page_23">23</a>, <a href="#Page_24">24</a></li>
+
+<li>Pine, southern, <a href="#Page_24">24</a></li>
+
+<li>Pine, southern hard, <a href="#Page_24">24</a></li>
+
+<li>Pine, spruce, <a href="#Page_26">26</a></li>
+
+<li>Pine, sugar, <a href="#Page_24">24</a></li>
+
+<li>Pine, swamp, <a href="#Page_26">26</a></li>
+
+<li>Pine, torch, <a href="#Page_26">26</a></li>
+
+<li>Pine, Weymouth, <a href="#Page_23">23</a></li>
+
+<li>Pine, western, <a href="#Page_25">25</a></li>
+
+<li>Pine, western white, <a href="#Page_25">25</a></li>
+
+<li>Pine, western yellow, <a href="#Page_25">25</a></li>
+
+<li>Pine, white, <a href="#Page_23">23</a>, <a href="#Page_24">24</a></li>
+
+<li>Pine, yellow, <a href="#Page_24">24</a>, <a href="#Page_25">25</a>, <a href="#Page_26">26</a></li>
+
+<li>Pin oak, <a href="#Page_73">73</a></li>
+
+<li>Pipe or moist-air kiln, <a href="#Page_188">188</a></li>
+
+<li>Pitch pine, <a href="#Page_26">26</a></li>
+
+<li>Pith and bark, <a href="#Page_8">8</a></li>
+
+<li>Plane tree, <a href="#Page_80">80</a></li>
+
+<li>Pocket dry kiln, the, <a href="#Page_200">200</a></li>
+
+<li>Point in wood, the fibre saturation, <a href="#Page_118">118</a></li>
+
+<li>Pole pine, lodge, <a href="#Page_27">27</a></li>
+
+<li>Poplar, <a href="#Page_67">67</a>, <a href="#Page_77">77</a>, <a href="#Page_79">79</a>, <a href="#Page_81">81</a><span class='pagenum'><a name="Page_270" id="Page_270">[270]</a></span></li>
+
+<li>Poplar, bay, <a href="#Page_60">60</a></li>
+
+<li>Poplar, blue, <a href="#Page_81">81</a></li>
+
+<li>Poplar, Carolina, <a href="#Page_77">77</a></li>
+
+<li>Poplar, downy, <a href="#Page_78">78</a></li>
+
+<li>Poplar, hickory, <a href="#Page_81">81</a></li>
+
+<li>Poplar, Lombardy, <a href="#Page_79">79</a></li>
+
+<li>Poplar, swamp, <a href="#Page_60">60</a></li>
+
+<li>Poplar, white, <a href="#Page_79">79</a>, <a href="#Page_81">81</a></li>
+
+<li>Poplar, yellow, <a href="#Page_81">81</a></li>
+
+<li>Port Orford cedar, <a href="#Page_18">18</a></li>
+
+<li>Possum oak, <a href="#Page_73">73</a></li>
+
+<li>Post borers, powder, <a href="#Page_105">105</a></li>
+
+<li>Post oak, <a href="#Page_74">74</a></li>
+
+<li>Post oak, swamp, <a href="#Page_73">73</a></li>
+
+<li>Pounds of water lost in drying 100 lb. green wood in the kiln, <a href="#Page_179">179</a></li>
+
+<li>Powder post borers, <a href="#Page_105">105</a></li>
+
+<li>Preliminary steaming of gum, <a href="#Page_182">182</a></li>
+
+<li>Preliminary treatments, <a href="#Page_151">151</a></li>
+
+<li>Pressure and vacuum, drying under, <a href="#Page_146">146</a></li>
+
+<li>Pressure, drying at atmospheric, <a href="#Page_146">146</a></li>
+
+<li>Prevent injury from insects, how to, <a href="#Page_107">107</a></li>
+
+<li>Prevention of checking and splitting, <a href="#Page_129">129</a></li>
+
+<li>Principles of kiln-drying, underlying, <a href="#Page_166">166</a></li>
+
+<li>Problems in kiln-drying, unsolved, <a href="#Page_143">143</a></li>
+
+<li>Products, crude, <a href="#Page_106">106</a></li>
+
+<li>Products in the rough, seasoned, <a href="#Page_112">112</a></li>
+
+<li>Products in the rough, unseasoned, <a href="#Page_109">109</a></li>
+
+<li>Progressive dry kiln, the, <a href="#Page_196">196</a></li>
+
+<li>Properties, characteristics and, <a href="#Page_1">1</a></li>
+
+<li>Properties of wood, <a href="#Page_4">4</a></li>
+
+<li>Properties of wood that affect drying, <a href="#Page_141">141</a></li>
+
+<li>Properties that influence drying, physical, <a href="#Page_125">125</a></li>
+
+<li>Puget Sound pine, <a href="#Page_29">29</a></li>
+
+<li>Pumpkin pine, <a href="#Page_23">23</a>, <a href="#Page_24">24</a></li>
+
+<li>Punk oak, <a href="#Page_73">73</a></li>
+
+<li>Pussy willow, <a href="#Page_84">84</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Quaking Aspen</span>, <a href="#Page_79">79</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Range of Red Gum</span>, <a href="#Page_55">55</a></li>
+
+<li>Range of tupelo gum, <a href="#Page_61">61</a></li>
+
+<li>Rapidity of evaporation, <a href="#Page_124">124</a></li>
+
+<li>Recording hygrometer, the, <a href="#Page_242">242</a></li>
+
+<li>Recording steam gauge, the, <a href="#Page_246">246</a></li>
+
+<li>Recording thermometer, the, <a href="#Page_245">245</a></li>
+
+<li>Records of the moisture content, keep, <a href="#Page_249">249</a></li>
+
+<li>Red ash, <a href="#Page_38">38</a></li>
+
+<li>Red beech, <a href="#Page_40">40</a></li>
+
+<li>Red birch, <a href="#Page_43">43</a></li>
+
+<li>Red cedar, <a href="#Page_18">18</a>, <a href="#Page_19">19</a></li>
+
+<li>Red cedar of the West, <a href="#Page_17">17</a></li>
+
+<li>Red cherry, <a href="#Page_47">47</a></li>
+
+<li>Red cherry, wild, <a href="#Page_47">47</a></li>
+
+<li>Red cypress, <a href="#Page_19">19</a></li>
+
+<li>Red elm, <a href="#Page_51">51</a></li>
+
+<li>Red fir, <a href="#Page_21">21</a>, <a href="#Page_29">29</a></li>
+
+<li>Red gum, <a href="#Page_54">54</a>, <a href="#Page_79">79</a></li>
+
+<li>Red gum, demands upon soil and moisture of, <a href="#Page_56">56</a></li>
+
+<li>Red gum, form of the, <a href="#Page_55">55</a></li>
+
+<li>Red gum, kiln-drying of green, <a href="#Page_183">183</a></li>
+
+<li>Red gum, range of, <a href="#Page_55">55</a></li>
+
+<li>Red gum, reproduction of, <a href="#Page_57">57</a></li>
+
+<li>Red gum, second-growth, <a href="#Page_59">59</a></li>
+
+<li>Red gum, tolerance of, <a href="#Page_56">56</a></li>
+
+<li>Red juniper, <a href="#Page_18">18</a></li>
+
+<li>Red maple, <a href="#Page_69">69</a></li>
+
+<li>Red mulberry, <a href="#Page_70">70</a></li>
+
+<li>Red oak, <a href="#Page_74">74</a>, <a href="#Page_75">75</a></li>
+
+<li>Red pine, <a href="#Page_29">29</a></li>
+
+<li>Red pine, American, <a href="#Page_25">25</a></li>
+
+<li>Red spruce, <a href="#Page_28">28</a></li>
+
+<li>Redwood, <a href="#Page_19">19</a>, <a href="#Page_27">27</a></li>
+
+<li>Redwood, California, <a href="#Page_19">19</a></li>
+
+<li>Redwood, Coast, <a href="#Page_19">19</a></li>
+
+<li>Registering hygrometer, the, <a href="#Page_244">244</a></li>
+
+<li>Registering thermometer, the, <a href="#Page_246">246</a></li>
+
+<li>Rendering drying difficult, changes, <a href="#Page_140">140</a></li>
+
+<li>Reproduction of red gum, <a href="#Page_57">57</a></li>
+
+<li>Requirements in a satisfactory dry kiln, <a href="#Page_160">160</a></li>
+
+<li>Ring, the annual or yearly, <a href="#Page_10">10</a></li>
+
+<li>River birch, <a href="#Page_43">43</a></li>
+
+<li>Rock chestnut oak, <a href="#Page_73">73</a></li>
+
+<li>Rock elm, <a href="#Page_50">50</a></li>
+
+<li>Rock maple, <a href="#Page_68">68</a></li>
+
+<li>Rock oak, <a href="#Page_73">73</a></li>
+
+<li>Rosemary pine, <a href="#Page_25">25</a></li>
+
+<li>Rough, seasoned products in the, <a href="#Page_112">112</a></li>
+
+<li>Rough, unseasoned products in the, <a href="#Page_109">109</a></li>
+
+<li>Round-headed borers, <a href="#Page_101">101</a></li>
+
+<li>Round timber with bark on, <a href="#Page_106">106</a></li>
+
+<li>Rum cherry, <a href="#Page_47">47</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Samples for Scalometer Test</span>, <a href="#Page_248">248</a><span class='pagenum'><a name="Page_271" id="Page_271">[271]</a></span></li>
+
+<li>Sand bar willow, <a href="#Page_84">84</a></li>
+
+<li>Sap and heartwood, <a href="#Page_8">8</a></li>
+
+<li>Sap, composition of, <a href="#Page_116">116</a></li>
+
+<li>Saplings, <a href="#Page_108">108</a></li>
+
+<li>Sap pine, <a href="#Page_25">25</a></li>
+
+<li>Sassafras, <a href="#Page_80">80</a></li>
+
+<li>Satin walnut, <a href="#Page_54">54</a></li>
+
+<li>Satisfactory dry kiln, requirements in a, <a href="#Page_160">160</a></li>
+
+<li>Saturation point in wood, fibre, <a href="#Page_118">118</a></li>
+
+<li>Sawmills, scalometer in, <a href="#Page_249">249</a></li>
+
+<li>Savin juniper, <a href="#Page_18">18</a></li>
+
+<li>Scalometer in factories, <a href="#Page_249">249</a></li>
+
+<li>Scalometer in sawmills, <a href="#Page_249">249</a></li>
+
+<li>Scalometer, test samples for, <a href="#Page_248">248</a></li>
+
+<li>Scalometer, the troemroid, <a href="#Page_247">247</a></li>
+
+<li>Scalometer, weighing with, <a href="#Page_248">248</a></li>
+
+<li>Scalybark hickory, <a href="#Page_64">64</a></li>
+
+<li>Scarlet oak, <a href="#Page_75">75</a></li>
+
+<li>Scrub chestnut oak, <a href="#Page_74">74</a></li>
+
+<li>Scrub oak, <a href="#Page_74">74</a></li>
+
+<li>Scrub pine, <a href="#Page_27">27</a></li>
+
+<li>Seasonal distribution of water in wood, <a href="#Page_115">115</a></li>
+
+<li>Seasoned and unseasoned wood, difference between, <a href="#Page_121">121</a></li>
+
+<li>Seasoned, how wood is, <a href="#Page_145">145</a></li>
+
+<li>Seasoned products in the rough, <a href="#Page_112">112</a></li>
+
+<li>Seasoning, advantages in, <a href="#Page_128">128</a></li>
+
+<li>Seasoning is, what, <a href="#Page_119">119</a></li>
+
+<li>Seasoning, out-of-door, <a href="#Page_154">154</a></li>
+
+<li>Second-growth red gum, <a href="#Page_59">59</a></li>
+
+<li>Sequoia, <a href="#Page_19">19</a></li>
+
+<li>Service kiln, theory and description of forest, <a href="#Page_161">161</a></li>
+
+<li>Shagbark hickory, <a href="#Page_64">64</a></li>
+
+<li>Shellbark hickory, <a href="#Page_64">64</a></li>
+
+<li>Shingle, heading and stave bolts, <a href="#Page_109">109</a></li>
+
+<li>Shingle oak, <a href="#Page_75">75</a></li>
+
+<li>Shining willow, <a href="#Page_84">84</a></li>
+
+<li>Short-leaf pine, <a href="#Page_26">26</a></li>
+
+<li>Short-straw pine, <a href="#Page_25">25</a></li>
+
+<li>Shrinkage of wood, <a href="#Page_130">130</a></li>
+
+<li>Shucks, honey, <a href="#Page_66">66</a></li>
+
+<li>Sitka spruce, <a href="#Page_28">28</a></li>
+
+<li>Silver birch, <a href="#Page_42">42</a></li>
+
+<li>Silver-leaved maple, <a href="#Page_69">69</a></li>
+
+<li>Silver maple, <a href="#Page_69">69</a></li>
+
+<li>Slash pine, <a href="#Page_25">25</a>, <a href="#Page_26">26</a></li>
+
+<li>Slippery elm, <a href="#Page_51">51</a></li>
+
+<li>Small-leaved basswood, <a href="#Page_39">39</a></li>
+
+<li>Small magnolia, <a href="#Page_67">67</a></li>
+
+<li>Soft maple, <a href="#Page_69">69</a></li>
+
+<li>Soft pine, <a href="#Page_23">23</a>, <a href="#Page_24">24</a></li>
+
+<li>Soil and moisture, demands upon, <a href="#Page_56">56</a></li>
+
+<li>Sorrel-tree, <a href="#Page_80">80</a></li>
+
+<li>Sound pine, Puget, <a href="#Page_29">29</a></li>
+
+<li>Sour gum, <a href="#Page_62">62</a>, <a href="#Page_80">80</a></li>
+
+<li>Sourwood, <a href="#Page_80">80</a></li>
+
+<li>Southern hard pine, <a href="#Page_24">24</a></li>
+
+<li>Southern pine, <a href="#Page_24">24</a></li>
+
+<li>Spanish oak, <a href="#Page_75">75</a></li>
+
+<li>Spanish oak, swamp, <a href="#Page_73">73</a></li>
+
+<li>Specialties, dry-kiln, <a href="#Page_206">206</a></li>
+
+<li>Species, different kiln-drying according to, <a href="#Page_170">170</a></li>
+
+<li>Species, temperature depends upon condition and, <a href="#Page_171">171</a></li>
+
+<li>Species, weight of kiln-dried wood of different, <a href="#Page_95">95</a></li>
+
+<li>Spindle tree, <a href="#Page_82">82</a></li>
+
+<li>Splitting, prevention of checking and, <a href="#Page_129">129</a></li>
+
+<li>Spring and summer-wood, <a href="#Page_12">12</a></li>
+
+<li>Spruce, <a href="#Page_27">27</a></li>
+
+<li>Spruce, bastard, <a href="#Page_29">29</a></li>
+
+<li>Spruce, black, <a href="#Page_27">27</a></li>
+
+<li>Spruce, Douglas, <a href="#Page_29">29</a></li>
+
+<li>Spruce, hemlock, <a href="#Page_21">21</a></li>
+
+<li>Spruce pine, <a href="#Page_26">26</a></li>
+
+<li>Spruce, red, <a href="#Page_28">28</a></li>
+
+<li>Spruce, Sitka, <a href="#Page_28">28</a></li>
+
+<li>Spruce, tide-land, <a href="#Page_28">28</a></li>
+
+<li>Spruce, white, <a href="#Page_28">28</a></li>
+
+<li>Stain and mildew, elimination of, <a href="#Page_136">136</a></li>
+
+<li>Stave, heading and shingle bolts, <a href="#Page_109">109</a></li>
+
+<li>Staves and heads of barrels containing alcoholic liquids, <a href="#Page_112">112</a></li>
+
+<li>Steam, drying by superheated, <a href="#Page_150">150</a></li>
+
+<li>Steam gauge, the recording, <a href="#Page_246">246</a></li>
+
+<li>Steaming of gum, preliminary, <a href="#Page_182">182</a></li>
+
+<li>Steaming of gum, final, <a href="#Page_182">182</a></li>
+
+<li>Stock and wooden truss hoops, dry cooperage, <a href="#Page_112">112</a></li>
+
+<li>Straw pine, long, <a href="#Page_24">24</a></li>
+
+<li>Straw pine, short, <a href="#Page_25">25</a></li>
+
+<li>Striped maple, <a href="#Page_70">70</a></li>
+
+<li>Structure, anatomical, <a href="#Page_14">14</a></li>
+
+<li>Structure, minute, <a href="#Page_34">34</a></li>
+
+<li>Structure of wood, <a href="#Page_4">4</a></li>
+
+<li>Stump tree, <a href="#Page_49">49</a></li>
+
+<li>Success in kiln-drying, conditions of, <a href="#Page_169">169</a></li>
+
+<li>Sugar berry, <a href="#Page_62">62</a></li>
+
+<li>Sugar maple, <a href="#Page_68">68</a><span class='pagenum'><a name="Page_272" id="Page_272">[272]</a></span></li>
+
+<li>Sugar pine, <a href="#Page_24">24</a></li>
+
+<li>Summerwood, spring and, <a href="#Page_12">12</a></li>
+
+<li>Superheated steam, drying by, <a href="#Page_150">150</a></li>
+
+<li>Swamp cottonwood, <a href="#Page_78">78</a></li>
+
+<li>Swamp hickory, <a href="#Page_64">64</a></li>
+
+<li>Swamp magnolia, <a href="#Page_67">67</a></li>
+
+<li>Swamp maple, <a href="#Page_69">69</a></li>
+
+<li>Swamp pine, <a href="#Page_26">26</a></li>
+
+<li>Swamp poplar, <a href="#Page_60">60</a></li>
+
+<li>Swamp post oak, <a href="#Page_73">73</a></li>
+
+<li>Swamp Spanish oak, <a href="#Page_73">73</a></li>
+
+<li>Swamp white oak, <a href="#Page_72">72</a>, <a href="#Page_73">73</a></li>
+
+<li>Sweet bay, <a href="#Page_67">67</a></li>
+
+<li>Sweet buckeye, <a href="#Page_45">45</a></li>
+
+<li>Sweet birch, <a href="#Page_41">41</a></li>
+
+<li>Sweet gum, <a href="#Page_54">54</a>, <a href="#Page_80">80</a></li>
+
+<li>Sweet locust, <a href="#Page_66">66</a></li>
+
+<li>Switchbud hickory, <a href="#Page_64">64</a></li>
+
+<li>Sycamore, <a href="#Page_80">80</a>, <a href="#Page_81">81</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Tacmahac</span>, <a href="#Page_79">79</a></li>
+
+<li>Tamarack, <a href="#Page_22">22</a>, <a href="#Page_27">27</a>, <a href="#Page_29">29</a></li>
+
+<li>Temperature depends upon conditions and species, <a href="#Page_171">171</a></li>
+
+<li>Test samples for scalometer, <a href="#Page_248">248</a></li>
+
+<li>Theory and description of the forest service kiln, <a href="#Page_161">161</a></li>
+
+<li>Theory of kiln-drying, <a href="#Page_157">157</a></li>
+
+<li>Thermometer, the recording, <a href="#Page_245">245</a></li>
+
+<li>Thermometer, the registering, <a href="#Page_246">246</a></li>
+
+<li>Thorned acacia, three, <a href="#Page_66">66</a></li>
+
+<li>Three-thorned acacia, <a href="#Page_66">66</a></li>
+
+<li>Tide-land spruce, <a href="#Page_28">28</a></li>
+
+<li>Timber, <a href="#Page_1">1</a></li>
+
+<li>Timber beetles, ambrosia or, <a href="#Page_99">99</a></li>
+
+<li>Timber with bark on, round, <a href="#Page_106">106</a></li>
+
+<li>Timber worms, <a href="#Page_103">103</a></li>
+
+<li>Tolerance of red gum, <a href="#Page_56">56</a></li>
+
+<li>Toothed aspen, large-, <a href="#Page_79">79</a></li>
+
+<li>Torch pine, <a href="#Page_26">26</a></li>
+
+<li>Tower dry kiln, the, <a href="#Page_202">202</a></li>
+
+<li>Treatments, preliminary, <a href="#Page_151">151</a></li>
+
+<li>Tree, abele, <a href="#Page_79">79</a></li>
+
+<li>Tree, bee, <a href="#Page_39">39</a></li>
+
+<li>Tree, button ball, <a href="#Page_80">80</a></li>
+
+<li>Tree, coffee, <a href="#Page_49">49</a></li>
+
+<li>Tree, cucumber, <a href="#Page_49">49</a>, <a href="#Page_67">67</a></li>
+
+<li>Tree, fir, <a href="#Page_20">20</a></li>
+
+<li>Tree, lime, <a href="#Page_39">39</a></li>
+
+<li>Tree, nettle, <a href="#Page_62">62</a></li>
+
+<li>Tree of life, <a href="#Page_17">17</a></li>
+
+<li>Tree, plane, <a href="#Page_80">80</a></li>
+
+<li>Trees, broad-leaved, <a href="#Page_31">31</a></li>
+
+<li>Trees, classes of, <a href="#Page_5">5</a></li>
+
+<li>Trees, coniferous, <a href="#Page_8">8</a></li>
+
+<li>Trees, list of important coniferous, <a href="#Page_17">17</a></li>
+
+<li>Trees, list of most important broad-leaved, <a href="#Page_37">37</a></li>
+
+<li>Tree, sorrel, <a href="#Page_80">80</a></li>
+
+<li>Tree, spindle, <a href="#Page_82">82</a></li>
+
+<li>Tree, stump, <a href="#Page_49">49</a></li>
+
+<li>Trees, wood of broad-leaved, <a href="#Page_31">31</a></li>
+
+<li>Trees, wood of the coniferous, <a href="#Page_8">8</a></li>
+
+<li>Tree, tulip, <a href="#Page_81">81</a></li>
+
+<li>Tree, umbrella, <a href="#Page_67">67</a></li>
+
+<li>Troemroid Scalometer, the, <a href="#Page_247">247</a></li>
+
+<li>Truss hoops, dry cooperage stock and, <a href="#Page_112">112</a></li>
+
+<li>Tulip tree, <a href="#Page_81">81</a></li>
+
+<li>Tulip wood, <a href="#Page_67">67</a>, <a href="#Page_81">81</a></li>
+
+<li>Tupelo, <a href="#Page_82">82</a></li>
+
+<li>Tupelo gum, <a href="#Page_60">60</a></li>
+
+<li>Tupelo gum, range of, <a href="#Page_61">61</a></li>
+
+<li>Tupelo gum, uses of, <a href="#Page_61">61</a></li>
+
+<li>Types of dry kilns, different, <a href="#Page_185">185</a></li>
+
+<li>Types of kiln doors, different, <a href="#Page_231">231</a></li>
+
+<li>Types, kilns of different, <a href="#Page_196">196</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Umbrella Tree</span>, <a href="#Page_67">67</a></li>
+
+<li>Underlying principles of kiln-drying, <a href="#Page_166">166</a></li>
+
+<li>Unseasoned products in the rough, <a href="#Page_109">109</a></li>
+
+<li>Unseasoned wood, difference between seasoned and, <a href="#Page_121">121</a></li>
+
+<li>Unsolved problems in kiln-drying, <a href="#Page_143">143</a></li>
+
+<li>Uses of the humidity diagram, <a href="#Page_237">237</a></li>
+
+<li>Uses of tupelo gum, <a href="#Page_61">61</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Vacuum, Drying under Pressure and</span>, <a href="#Page_146">146</a></li>
+
+<li>Valparaiso oak, <a href="#Page_76">76</a></li>
+
+<li>Virgilia, <a href="#Page_85">85</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Wahoo</span>, <a href="#Page_51">51</a>, <a href="#Page_82">82</a></li>
+
+<li>Walnut, <a href="#Page_45">45</a>, <a href="#Page_82">82</a></li>
+
+<li>Walnut, black, <a href="#Page_44">44</a>, <a href="#Page_82">82</a></li>
+
+<li>Walnut, circassian, <a href="#Page_60">60</a></li>
+
+<li>Walnut, satin, <a href="#Page_54">54</a></li>
+
+<li>Walnut, white, <a href="#Page_45">45</a>, <a href="#Page_83">83</a></li>
+
+<li>Water beech, <a href="#Page_44">44</a>, <a href="#Page_80">80</a></li>
+
+<li>Water by dry wood, absorption of, <a href="#Page_124">124</a></li>
+
+<li>Water elm, <a href="#Page_50">50</a><span class='pagenum'><a name="Page_273" id="Page_273">[273]</a></span></li>
+
+<li>Water in wood, <a href="#Page_114">114</a></li>
+
+<li>Water in wood, distribution of, <a href="#Page_114">114</a></li>
+
+<li>Water in wood, local distribution of, <a href="#Page_114">114</a></li>
+
+<li>Water in wood, seasonal distribution of, <a href="#Page_115">115</a></li>
+
+<li>Water lost in drying 100 lb. of green wood in the kiln, pounds of, <a href="#Page_179">179</a></li>
+
+<li>Water, manner of evaporation of, <a href="#Page_123">123</a></li>
+
+<li>Water maple, <a href="#Page_69">69</a></li>
+
+<li>Water oak, <a href="#Page_73">73</a></li>
+
+<li>Weeping willow, <a href="#Page_84">84</a></li>
+
+<li>Weighing with scalometer, <a href="#Page_248">248</a></li>
+
+<li>Weight, and figure in wood, grain, color, odor, <a href="#Page_86">86</a></li>
+
+<li>Weight of kiln-dried wood of different species, <a href="#Page_95">95</a></li>
+
+<li>Weight of wood, <a href="#Page_91">91</a></li>
+
+<li>Western larch, <a href="#Page_22">22</a></li>
+
+<li>Western pine, <a href="#Page_25">25</a></li>
+
+<li>Western white oak, <a href="#Page_71">71</a></li>
+
+<li>Western white pine, <a href="#Page_25">25</a></li>
+
+<li>Western yellow pine, <a href="#Page_25">25</a></li>
+
+<li>West, red cedar of the, <a href="#Page_17">17</a></li>
+
+<li>Weymouth pine, <a href="#Page_23">23</a></li>
+
+<li>What seasoning is, <a href="#Page_119">119</a></li>
+
+<li>White ash, <a href="#Page_37">37</a></li>
+
+<li>White basswood, <a href="#Page_39">39</a></li>
+
+<li>White beech, <a href="#Page_40">40</a></li>
+
+<li>White birch, <a href="#Page_42">42</a>, <a href="#Page_43">43</a></li>
+
+<li>White cedar, <a href="#Page_17">17</a>, <a href="#Page_18">18</a></li>
+
+<li>White cypress, <a href="#Page_19">19</a></li>
+
+<li>White elm, <a href="#Page_50">50</a></li>
+
+<li>White fir, <a href="#Page_20">20</a>, <a href="#Page_21">21</a></li>
+
+<li>White heart hickory, <a href="#Page_64">64</a></li>
+
+<li>White mahogany, <a href="#Page_45">45</a></li>
+
+<li>White maple, <a href="#Page_69">69</a></li>
+
+<li>White oak, <a href="#Page_71">71</a>, <a href="#Page_72">72</a></li>
+
+<li>White oak, swamp, <a href="#Page_72">72</a>, <a href="#Page_73">73</a></li>
+
+<li>White oak, western, <a href="#Page_71">71</a></li>
+
+<li>White pine, <a href="#Page_23">23</a>, <a href="#Page_24">24</a></li>
+
+<li>White pine, California, <a href="#Page_25">25</a></li>
+
+<li>White pine, western, <a href="#Page_25">25</a></li>
+
+<li>White poplar, <a href="#Page_79">79</a>, <a href="#Page_81">81</a></li>
+
+<li>White spruce, <a href="#Page_28">28</a></li>
+
+<li>White walnut, <a href="#Page_45">45</a>, <a href="#Page_83">83</a></li>
+
+<li>White willow, <a href="#Page_83">83</a></li>
+
+<li>Whitewood, <a href="#Page_39">39</a>, <a href="#Page_81">81</a>, <a href="#Page_83">83</a></li>
+
+<li>Wild apple, <a href="#Page_49">49</a></li>
+
+<li>Wild cherry, <a href="#Page_47">47</a></li>
+
+<li>Wild red cherry, <a href="#Page_47">47</a></li>
+
+<li>Willow, <a href="#Page_83">83</a></li>
+
+<li>Willow, almond-leaf, <a href="#Page_84">84</a></li>
+
+<li>Willow, bebb, <a href="#Page_84">84</a></li>
+
+<li>Willow, black, <a href="#Page_83">83</a></li>
+
+<li>Willow, blue, <a href="#Page_83">83</a></li>
+
+<li>Willow, crack, <a href="#Page_84">84</a></li>
+
+<li>Willow, glaucous, <a href="#Page_84">84</a></li>
+
+<li>Willow, long-leaf, <a href="#Page_84">84</a></li>
+
+<li>Willow, oak, <a href="#Page_72">72</a></li>
+
+<li>Willow, perch, <a href="#Page_84">84</a></li>
+
+<li>Willow, pussy, <a href="#Page_84">84</a></li>
+
+<li>Willow, sand bar, <a href="#Page_84">84</a></li>
+
+<li>Willow, shining, <a href="#Page_84">84</a></li>
+
+<li>Willow, weeping, <a href="#Page_84">84</a></li>
+
+<li>Willow, white, <a href="#Page_83">83</a></li>
+
+<li>Willow, yellow, <a href="#Page_83">83</a></li>
+
+<li>Winged elm, <a href="#Page_51">51</a></li>
+
+<li>Wintergreen birch, <a href="#Page_41">41</a></li>
+
+<li>Wood, absorption of water by dry, <a href="#Page_124">124</a></li>
+
+<li>Wood, beaver, <a href="#Page_67">67</a></li>
+
+<li>Wood, canary, <a href="#Page_81">81</a></li>
+
+<li>Wood, characteristics and properties of, <a href="#Page_1">1</a></li>
+
+<li>Wood, color and odor of, <a href="#Page_89">89</a></li>
+
+<li>Wood, different grains of, <a href="#Page_86">86</a></li>
+
+<li>Wood, difference between seasoned and unseasoned, <a href="#Page_121">121</a></li>
+
+<li>Wood, difficulties of drying, <a href="#Page_138">138</a></li>
+
+<li>Wood, distribution of water in, <a href="#Page_114">114</a></li>
+
+<li>Wood, effects of moisture on, <a href="#Page_117">117</a></li>
+
+<li>Wood, enemies of, <a href="#Page_98">98</a></li>
+
+<li>Wood, expansion of, <a href="#Page_135">135</a></li>
+
+<li>Wood, figure in, <a href="#Page_96">96</a></li>
+
+<li>Wood, grain, color, odor, weight, and figure in, <a href="#Page_86">86</a></li>
+
+<li>Wood, how seasoned, <a href="#Page_145">145</a></li>
+
+<li>Wood in the kiln, pounds of water lost in drying 100 lb. of green, <a href="#Page_179">179</a></li>
+
+<li>Wood, iron, <a href="#Page_65">65</a></li>
+
+<li>Wood, kiln-drying of, <a href="#Page_156">156</a></li>
+
+<li>Wood, lever, <a href="#Page_65">65</a></li>
+
+<li>Wood, local distribution of water in, <a href="#Page_114">114</a></li>
+
+<li>Wood, moose, <a href="#Page_70">70</a></li>
+
+<li>Wood, of broad-leaves trees, <a href="#Page_31">31</a></li>
+
+<li>Wood of different species, weight of kiln-dried, <a href="#Page_95">95</a></li>
+
+<li>Wood of coniferous trees, <a href="#Page_8">8</a></li>
+
+<li>Wood, physical conditions governing the drying of, <a href="#Page_156">156</a><span class='pagenum'><a name="Page_274" id="Page_274">[274]</a></span></li>
+
+<li>Wood, properties of, <a href="#Page_4">4</a></li>
+
+<li>Wood, seasonal distribution of water in, <a href="#Page_115">115</a></li>
+
+<li>Wood, shrinkage of, <a href="#Page_130">130</a></li>
+
+<li>Woods, list of important coniferous, <a href="#Page_17">17</a></li>
+
+<li>Wood, spring and summer, <a href="#Page_12">12</a></li>
+
+<li>Wood, structure of, <a href="#Page_4">4</a></li>
+
+<li>Wood that effect drying, properties of, <a href="#Page_141">141</a></li>
+
+<li>Wood, the fibre saturation point in, <a href="#Page_118">118</a></li>
+
+<li>Wood, tulip, <a href="#Page_67">67</a>, <a href="#Page_81">81</a></li>
+
+<li>Wood, water in, <a href="#Page_114">114</a></li>
+
+<li>Wood, weight of, <a href="#Page_89">89</a></li>
+
+<li>Wood, white, <a href="#Page_81">81</a>, <a href="#Page_83">83</a></li>
+
+<li>Wood, yellow, <a href="#Page_85">85</a></li>
+
+<li>Wooden truss hoops, dry cooperage, stock and, <a href="#Page_112">112</a></li>
+
+<li>Worms, timber, <a href="#Page_103">103</a></li>
+<li>&nbsp;</li>
+
+<li><span class="smcap">Yearly Ring, the Annual of</span>, <a href="#Page_10">10</a></li>
+
+<li>Yellow birch, <a href="#Page_42">42</a></li>
+
+<li>Yellow cedar, <a href="#Page_18">18</a></li>
+
+<li>Yellow deal, <a href="#Page_23">23</a></li>
+
+<li>Yellow fir, <a href="#Page_29">29</a></li>
+
+<li>Yellow locust, <a href="#Page_66">66</a></li>
+
+<li>Yellow oak, <a href="#Page_73">73</a>, <a href="#Page_74">74</a></li>
+
+<li>Yellow pine, <a href="#Page_24">24</a>, <a href="#Page_25">25</a>, <a href="#Page_26">26</a></li>
+
+<li>Yellow pine, western, <a href="#Page_25">25</a></li>
+
+<li>Yellow poplar, <a href="#Page_81">81</a></li>
+
+<li>Yellow willow, <a href="#Page_83">83</a></li>
+
+<li>Yellow wood, <a href="#Page_85">85</a></li>
+
+<li>Yew, <a href="#Page_29">29</a>, <a href="#Page_30">30</a></li>
+</ul>
+
+<div class="advertisements">
+
+<div class="bbox">
+
+<p class="center bb" style="letter-spacing: 0.20ex; line-height: 180%"><big><b>D. VAN NOSTRAND COMPANY</b></big><br /><span class='pagenum'><a name="Page_1a" id="Page_1a">[1]</a></span>
+25 PARK PLACE<br />
+NEW YORK</p>
+
+<p class="center" style="line-height: 200%"><span style="font-size: 130%; font-weight: bold">SHORT-TITLE CATALOG</span><br />
+<small>OF</small><br />
+<span style="font-size: 130%; font-weight: bold">Publications and Importations</span><br />
+<small>OF</small><br />
+<span style="font-size: 110%">SCIENTIFIC AND ENGINEERING</span><br />
+<span style="font-size: 110%">BOOKS</span></p>
+
+<div class="figcenter" style="width: 50px; padding-top: 2em; padding-bottom: 2em">
+<img src="images/advert2.jpg" width="50" height="53" alt="" title="" />
+</div>
+
+<p class="center bt">This list includes<br />
+the technical publications of the following English publishers:</p>
+
+<p class="center">SCOTT, GREENWOOD &amp;<span style="padding-left: 1em"> CO. JAMES MUNRO &amp; CO., Ltd.</span><br />
+CONSTABLE &amp; COMPANY, Ltd. TECHNICAL PUBLISHING CO.<br />
+ELECTRICIAN PRINTING &amp; PUBLISHING CO.<br />
+
+for whom D. Van Nostrand Company are American agents.</p>
+</div>
+<p class="right" style="padding-top: 4em"><span class="smcap">July, 1917</span></p>
+
+<p class="center" style="line-height: 180%; font-weight: bold"><span style="font-size: 150%">SHORT-TITLE CATALOG</span><span class='pagenum'><a name="Page_2a" id="Page_2a">[2]</a></span><br />
+
+<small>OF THE</small><br />
+
+<span style="font-size: 150%">Publications and Importations</span><br />
+
+<small>OF</small><br />
+
+<span style="font-size: 130%">D. VAN NOSTRAND COMPANY</span><br />
+
+<span style="font-size: 130%">25 PARK PLACE, N.&nbsp;Y.</span></p>
+
+<p class="center"><i>Prices marked with an asterisk (*) are NET.</i><br />
+
+<i>All bindings are in cloth unless otherwise noted.</i></p>
+
+
+
+
+<table summary="catalog" style="margin-bottom: 4em">
+<tr><td class="catent">Abbott, A.&nbsp;V. The Electrical Transmission of Energy</td><td class="catvolume">8vo,</td><td class="catprice">*$5 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; A Treatise on Fuel. (Science Series No. 9)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Testing Machines. (Science Series No. 74.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Adam, P. Practical Bookbinding. Trans. by T.&nbsp;E. Maw</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Adams, H. Theory and Practice in Designing</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Adams, H.&nbsp;C. Sewage of Sea Coast Towns</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Adams, J.&nbsp;W. Sewers and Drains for Populous Districts</td><td class="catvolume">8vo,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">Adler, A.&nbsp;A. Theory of Engineering Drawing</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Principles of Parallel Projecting-line Drawing</td><td class="catvolume">8vo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Aikman, C.&nbsp;M. Manures and the Principles of Manuring</td><td class="catvolume">8vo,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">Aitken, W. Manual of the Telephone</td><td class="catvolume">8vo,</td><td class="catprice">*8 00</td></tr>
+
+<tr><td class="catent">d'Albe, E.&nbsp;E.&nbsp;F., Contemporary Chemistry</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Alexander, J.&nbsp;H. Elementary Electrical Engineering</td><td class="catvolume">12mo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Allan, W. Strength of Beams Under Transverse Loads. (Science Series
+  No. 19.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Theory of Arches. (Science Series No. 11)</td><td class="catvolume">16mo,</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Allen, H. Modern Power Gas Producer Practice and Applications.</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Anderson, J.&nbsp;W. Prospector's Handbook</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">And&eacute;s, L. Vegetable Fats and Oils</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Animal Fats and Oils. Trans. by C. Salter</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Drying Oils, Boiled Oil, and Solid and Liquid Driers</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Iron Corrosion, Anti-fouling and Anti-corrosive Paints. Trans. by
+  C. Salter</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Oil Colors, and Printers' Ink. Trans. by A. Morris and H.
+  Robson</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Treatment of Paper for Special Purposes. Trans. by C. Salter</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Andrews, E.&nbsp;S. Reinforced Concrete Construction</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Theory and Design of Structures</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Further Problems in the Theory and Design of Structures</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; The Strength of Materials</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Andrews, E.&nbsp;S., and Heywood, H.&nbsp;B. The Calculus for Engineers.</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Annual Reports on the Progress of Chemistry. Twelve Volumes now
+  ready. Vol. I., 1904, Vol. XII., 1914</td><td class="catvolume">8vo, each,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Argand, M. Imaginary Quantities. Translated from the French by
+A.&nbsp;S. Hardy. (Science Series No. 52.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50<span class='pagenum'><a name="Page_3a" id="Page_3a">[3]</a></span></td></tr>
+
+<tr><td class="catent">Armstrong, R., and Idell, F.&nbsp;E. Chimneys for Furnaces and Steam Boilers.
+(Science Series No. 1.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Arnold, E. Armature Windings of Direct-Current Dynamos. Trans. by
+F.&nbsp;B. DeGress</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Asch, W., and Asch, D. The Silicates in Chemistry and Commerce</td><td class="catvolume">8vo,</td><td class="catprice">*6 00</td></tr>
+
+<tr><td class="catent">Ashe, S.&nbsp;W., and Kelley, J.&nbsp;D. Electric Railways. Theoretically and
+Practically Treated. Vol. I. Rolling Stock</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Ashe, S.&nbsp;W. Electric Railways. Vol. II. Engineering Preliminaries and
+Direct Current Sub-Stations</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Electricity: Experimentally and Practically Applied</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Ashley, R.&nbsp;H. Chemical Calculations</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Atkins, W. Common Battery Telephony Simplified</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Atkinson, A.&nbsp;A. Electrical and Magnetic Calculations</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Atkinson, J.&nbsp;J. Friction of Air in Mines. (Science Series No. 14.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Atkinson, J.&nbsp;J., and Williams, Jr., E.&nbsp;H. Gases Met with in Coal Mines.
+(Science Series No. 13.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Atkinson, P. The Elements of Electric Lighting</td><td class="catvolume">12mo,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; The Elements of Dynamic Electricity and Magnetism</td><td class="catvolume">12mo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Power Transmitted by Electricity</td><td class="catvolume">12mo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Auchincloss, W.&nbsp;S. Link and Valve Motions Simplified</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Austin, E. Single Phase Electric Railways</td><td class="catvolume">4to,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Austin and Cohn. Pocketbook of Radiotelegraphy</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Ayrton, H. The Electric Arc</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+<tr><td class="catent">Bacon, F.&nbsp;W. Treatise on the Richards Steam-Engine Indicator</td><td class="catvolume">12mo,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">Bailey, R.&nbsp;D. The Brewers' Analyst</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Baker, A.&nbsp;L. Quaternions</td><td class="catvolume">8vo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Thick-Lens Optics</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Baker, Benj. Pressure of Earthwork. (Science Series No. 56.)</td><td class="catvolume">16mo,</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Baker, G.&nbsp;S. Ship Form, Resistance and Screw Propulsion</td><td class="catvolume">8vo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">Baker, I.&nbsp;O. Levelling. (Science Series No. 91.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Baker, M.&nbsp;N. Potable Water. (Science Series No. 61.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Sewerage and Sewage Purification. (Science Series No. 18.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Baker, T.&nbsp;T. Telegraphic Transmission of Photographs</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Bale, G.&nbsp;R. Modern Iron Foundry Practice. Two Volumes.</td><td class="catvolume">12mo.</td><td class="catprice">&nbsp;</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. I. Foundry Equipment, Materials Used</td><td class="catvolume">&nbsp;</td><td class="catprice">*2 50</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. II. Machine Moulding and Moulding Machines</td><td class="catvolume">&nbsp;</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Ball, J.&nbsp;W. Concrete Structures in Railways</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Ball, R.&nbsp;S. Popular Guide to the Heavens</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Natural Sources of Power. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Ball, W.&nbsp;V. Law Affecting Engineers</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Bankson, Lloyd. Slide Valve Diagrams. (Science Series No. 108.).</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Barham, G.&nbsp;B. Development of the Incandescent Electric Lamp</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Barker, A.&nbsp;F. Textiles and Their Manufacture. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Barker, A.&nbsp;F., and Midgley, E. Analysis of Textile Fabrics</td><td class="catvolume">8vo,</td><td class="catprice">3 00</td></tr>
+
+<tr><td class="catent">Barker, A.&nbsp;H. Graphic Methods of Engine Design</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Heating and Ventilation</td><td class="catvolume">4to,</td><td class="catprice">*8 00</td></tr>
+
+<tr><td class="catent">Barnard, J.&nbsp;H. The Naval Militiaman's Guide</td><td class="catvolume">16mo, leather,</td><td class="catprice">1 00<span class='pagenum'><a name="Page_4a" id="Page_4a">[4]</a></span></td></tr>
+
+<tr><td class="catent">Barnard, Major J.&nbsp;G. Rotary Motion. (Science Series No. 90.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Barnes, J.&nbsp;B. Elements of Military Sketching</td><td class="catvolume">16mo,</td><td class="catprice">*0 60</td></tr>
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+<tr><td class="catent">Barrus, G.&nbsp;H. Engine Tests</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Barwise, S. The Purification of Sewage</td><td class="catvolume">12mo,</td><td class="catprice">3 50</td></tr>
+
+<tr><td class="catent">Baterden, J.&nbsp;R. Timber. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Bates, E.&nbsp;L., and Charlesworth, F. Practical Mathematics and Geometry</td><td class="catvolume">12mo,</td><td class="catprice">&nbsp;</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Part I. Preliminary and Elementary Course</td><td class="catvolume">&nbsp;</td><td class="catprice">*1 50</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Part II. Advanced Course</td><td class="catvolume">&nbsp;</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Practical Mathematics</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
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+<tr><td class="catent">&mdash;&mdash; Practical Geometry and Graphics</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
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+<tr><td class="catent">Batey, J. The Science of Works Management</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
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+<tr><td class="catent">&mdash;&mdash; Steam Boilers and Combustion</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
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+<tr><td class="catent">Bayonet Training Manual</td><td class="catvolume">16mo,</td><td class="catprice">0 30</td></tr>
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+<tr><td class="catent">Beadle, C. Chapters on Papermaking. Five Volumes</td><td class="catvolume">12mo, each,</td><td class="catprice">*2 00</td></tr>
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+<tr><td class="catent">Beaumont, R. Color in Woven Design</td><td class="catvolume">8vo,</td><td class="catprice">*6 00</td></tr>
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+<tr><td class="catent">&mdash;&mdash; Finishing of Textile Fabrics</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
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+<tr><td class="catent">&mdash;&mdash; Standard Cloths</td><td class="catvolume"> 8vo,</td><td class="catprice">*5 00</td></tr>
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+<tr><td class="catent">Beaumont, W.&nbsp;W. The Steam-Engine Indicator</td><td class="catvolume">8vo,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">Bechhold, H. Colloids in Biology and Medicine. Trans. by J.&nbsp;G. Bullowa</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
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+<tr><td class="catent">Beckwith, A. Pottery</td><td class="catvolume">8vo, paper,</td><td class="catprice">0 60</td></tr>
+
+<tr><td class="catent">Bedell, F., and Pierce, C.&nbsp;A. Direct and Alternating Current Manual</td><td class="catvolume">8vo,</td><td class="catprice">4 00</td></tr>
+
+<tr><td class="catent">Beech, F. Dyeing of Cotton Fabrics</td><td class="catvolume">8vo,</td><td class="catprice">4 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Dyeing of Woolen Fabrics</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
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+<tr><td class="catent">Begtrup, J. The Slide Valve</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Beggs, G.&nbsp;E. Stresses in Railway Girders and Bridges</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Bender, C.&nbsp;E. Continuous Bridges. (Science Series No. 26.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Proportions of Pins used in Bridges. (Science Series No. 4.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Bengough, G.&nbsp;D. Brass. (Metallurgy Series.)</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Bennett, H.&nbsp;G. The Manufacture of Leather</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Bernthsen, A. A Text book of Organic Chemistry. Trans. by G. M'Gowan</td><td class="catvolume">12mo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Bersch. J. Manufacture of Mineral and Lake Pigments.
+Trans. by A.&nbsp;C. Wright</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Bertin, L.&nbsp;E. Marine Boilers. Trans. by L.&nbsp;S. Robertson</td><td class="catvolume">8vo,</td><td class="catprice">5 00</td></tr>
+
+<tr><td class="catent">Beveridge, J. Papermaker's Pocket Book</td><td class="catvolume">12mo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Binnie, Sir A. Rainfall Reservoirs and Water Supply</td><td class="catvolume">8vo,</td><td class="catprice">3 00</td></tr>
+
+<tr><td class="catent">Binns, C.&nbsp;F. Manual of Practical Potting</td><td class="catvolume">8vo,</td><td class="catprice">*7 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; The Potter's Craft</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Birchmore, W.&nbsp;H. Interpretation of Gas Analysis</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Blaine, R.&nbsp;G. The Calculus and Its Applications</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Blake, W.&nbsp;H. Brewers' Vade Mecum</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Blasdale, W.&nbsp;C. Quantitative Chemical Analysis. (Van Nostrand's
+Textbooks.)</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Bligh, W.&nbsp;G. The Practical Design of Irrigation Works</td><td class="catvolume">8vo,</td><td class="catprice">*6 00</td></tr>
+
+<tr><td class="catent">Bloch, L. Science of Illumination. Trans. by W.&nbsp;C. Clinton</td><td class="catvolume">8vo,</td><td class="catprice">*2 50<span class='pagenum'><a name="Page_5a" id="Page_5a">[5]</a></span></td></tr>
+
+<tr><td class="catent">Blok, A. Illumination and Artificial Lighting</td><td class="catvolume">12mo,</td><td class="catprice">1 25</td></tr>
+
+<tr><td class="catent">Bl&uuml;cher, H. Modern Industrial Chemistry. Trans. by J.&nbsp;P. Millington.</td><td class="catvolume">8vo,</td><td class="catprice">*7 50</td></tr>
+
+<tr><td class="catent">Blyth, A.&nbsp;W. Foods: Their Composition and Analysis</td><td class="catvolume">8vo,</td><td class="catprice">7 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Poisons: Their Effects and Detection</td><td class="catvolume">8vo,</td><td class="catprice">7 50</td></tr>
+
+<tr><td class="catent">B&ouml;ckmann, F. Celluloid</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Bodmer, G.&nbsp;R. Hydraulic Motors and Turbines</td><td class="catvolume">12mo,</td><td class="catprice">5 00</td></tr>
+
+<tr><td class="catent">Boileau, J.&nbsp;T. Traverse Tables</td><td class="catvolume">8vo,</td><td class="catprice">5 00</td></tr>
+
+<tr><td class="catent">Bonney, G.&nbsp;E. The Electro-platers' Handbook</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Booth, N. Guide to the Ring-spinning Frame</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Booth, W.&nbsp;H. Water Softening and Treatment</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Superheaters and Superheating and Their Control</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Bottcher, A. Cranes: Their Construction, Mechanical Equipment and
+  Working. Trans. by A. Tolhausen</td><td class="catvolume">4to,</td><td class="catprice">*10 00</td></tr>
+
+<tr><td class="catent">Bottler, M. Modern Bleaching Agents. Trans. by C. Salter</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Bottone, S.&nbsp;R. Magnetos for Automobilists</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Boulton, S.&nbsp;B. Preservation of Timber. (Science Series No. 82.).</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Bourcart, E. Insecticides, Fungicides and Weedkillers</td><td class="catvolume">8vo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">Bourgougnon, A. Physical Problems. (Science Series No. 113.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Bourry, E. Treatise on Ceramic Industries. Trans. by A.&nbsp;B. Searle.</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Bowie, A.&nbsp;J., Jr. A Practical Treatise on Hydraulic Mining</td><td class="catvolume">8vo,</td><td class="catprice">5 00</td></tr>
+
+<tr><td class="catent">Bowles, O. Tables of Common Rocks. (Science Series No. 125.).</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Bowser, E.&nbsp;A. Elementary Treatise on Analytic Geometry</td><td class="catvolume">12mo,</td><td class="catprice">1 75</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Elementary Treatise on the Differential and Integral Calculus.</td><td class="catvolume">12mo,</td><td class="catprice">2 25</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Elementary Treatise on Analytic Mechanics</td><td class="catvolume">12mo,</td><td class="catprice">3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Elementary Treatise on Hydro-mechanics</td><td class="catvolume">12mo,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; A Treatise on Roofs and Bridges</td><td class="catvolume">12mo,</td><td class="catprice">*2 25</td></tr>
+
+<tr><td class="catent">Boycott, G.&nbsp;W.&nbsp;M. Compressed Air Work and Diving</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Bragg, E.&nbsp;M. Marine Engine Design</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Design of Marine Engines and Auxiliaries</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Brainard, F.&nbsp;R. The Sextant. (Science Series No. 101.)</td><td class="catvolume">16mo,</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Brassey's Naval Annual for 1915. War Edition</td><td class="catvolume">8vo,</td><td class="catprice">4 00</td></tr>
+
+<tr><td class="catent">Briggs, R., and Wolff, A.&nbsp;R. Steam-Heating. (Science Series No.
+67.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Bright, C. The Life Story of Sir Charles Tilson Bright</td><td class="catvolume">8vo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">Brislee, T.&nbsp;J. Introduction to the Study of Fuel. (Outlines of Industrial
+Chemistry.)</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Broadfoot, S.&nbsp;K. Motors, Secondary Batteries. (Installation Manuals
+Series.)</td><td class="catvolume">12mo,</td><td class="catprice">*0 75</td></tr>
+
+<tr><td class="catent">Broughton, H.&nbsp;H. Electric Cranes and Hoists</td><td class="catvolume">&nbsp;</td><td class="catprice">*9 00</td></tr>
+
+<tr><td class="catent">Brown, G. Healthy Foundations. (Science Series No. 80.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Brown, H. Irrigation</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Brown, H. Rubber</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; W.&nbsp;A. Portland Cement Industry</td><td class="catvolume">8vo,</td><td class="catprice">3 00</td></tr>
+
+<tr><td class="catent">Brown, Wm. N. Dipping, Burnishing, Lacquering and Bronzing
+  Brass Ware</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Handbook on Japanning</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Brown, Wm. N. The Art of Enamelling on Metal</td><td class="catvolume">12mo,</td><td class="catprice">*1 00<span class='pagenum'><a name="Page_6a" id="Page_6a">[6]</a></span></td></tr>
+
+<tr><td class="catent">&mdash;&mdash; House Decorating and Painting</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; History of Decorative Art</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Workshop Wrinkles</td><td class="catvolume">8vo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Browne, C.&nbsp;L. Fitting and Erecting of Engines</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Browne, R.&nbsp;E. Water Meters. (Science Series No. 81.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Bruce, E.&nbsp;M. Pure Food Tests</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Brunner, R. Manufacture of Lubricants, Shoe Polishes and Leather
+  Dressings. Trans. by C. Salter</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Buel, R.&nbsp;H. Safety Valves. (Science Series No. 21.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Burley, G.&nbsp;W. Lathes, Their Construction and Operation</td><td class="catvolume">12mo,</td><td class="catprice">1 25</td></tr>
+
+<tr><td class="catent">Burnside, W. Bridge Foundations</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Burstall, F.&nbsp;W. Energy Diagram for Gas. With Text</td><td class="catvolume">8vo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Diagram. Sold separately</td><td class="catvolume">&nbsp;</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Burt, W.&nbsp;A. Key to the Solar Compass</td><td class="catvolume">16mo, leather,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">Buskett, E.&nbsp;W. Fire Assaying</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Butler, H.&nbsp;J. Motor Bodies and Chassis</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Byers, H.&nbsp;G., and Knight, H.&nbsp;G. Notes on Qualitative Analysis </td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Cain, W. Brief Course in the Calculus</td><td class="catvolume">12mo,</td><td class="catprice">*1 75</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Elastic Arches. (Science Series No. 48.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Maximum Stresses. (Science Series No. 38.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Practical Designing Retaining of Walls. (Science Series No. 3.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Theory of Steel-concrete Arches and of Vaulted Structures.
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+
+<tr><td class="catent">&mdash;&mdash; Theory of Voussoir Arches. (Science Series No. 12.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Symbolic Algebra. (Science Series No. 73.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Carpenter, F.&nbsp;D. Geographical Surveying. (Science Series No. 37.)</td><td class="catvolume">16mo,</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Carpenter, R.&nbsp;C., and Diederichs, H. Internal Combustion Engines</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Carter, H.&nbsp;A. Ramie (Rhea), China Grass</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
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+<tr><td class="catent">Carter, H.&nbsp;R. Modern Flax, Hemp, and Jute Spinning</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Bleaching, Dyeing and Finishing of Fabrics</td><td class="catvolume">8vo,</td><td class="catprice">*1 00</td></tr>
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+<tr><td class="catent">Cary, E.&nbsp;R. Solution of Railroad Problems with the Slide Rule</td><td class="catvolume">16mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Casler, M.&nbsp;D. Simplified Reinforced Concrete Mathematics</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Cathcart, W.&nbsp;L. Machine Design. Part I. Fastenings</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
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+<tr><td class="catent">Cathcart, W.&nbsp;L., and Chaffee, J.&nbsp;I. Elements of Graphic Statics</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
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+<tr><td class="catent">&mdash;&mdash; Short Course in Graphics</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
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+<tr><td class="catent">Caven, R.&nbsp;M., and Lander, G.&nbsp;D. Systematic Inorganic Chemistry</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Chalkley, A.&nbsp;P. Diesel Engines</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Chambers' Mathematical Tables</td><td class="catvolume">8vo,</td><td class="catprice">1 75</td></tr>
+
+<tr><td class="catent">Chambers, G.&nbsp;F. Astronomy</td><td class="catvolume">16mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Chappel, E. Five Figure Mathematical Tables</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Charnock, Mechanical Technology</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Charpentier, P. Timber</td><td class="catvolume">8vo,</td><td class="catprice">*6 00</td></tr>
+
+<tr><td class="catent">Chatley, H. Principles and Designs of Aeroplanes. (Science Series
+  No. 126)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; How to Use Water Power</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Gyrostatic Balancing</td><td class="catvolume">8vo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Child, C.&nbsp;D. Electric Arc</td><td class="catvolume">8vo,</td><td class="catprice">*2 00<span class='pagenum'><a name="Page_7a" id="Page_7a">[7]</a></span></td></tr>
+
+<tr><td class="catent">Christian, M. Disinfection and Disinfectants. Trans. by Chas.
+  Salter</td><td class="catvolume">12mo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Christie, W.&nbsp;W. Boiler-waters, Scale, Corrosion, Foaming</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Chimney Design and Theory</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Furnace Draft. (Science Series No. 123.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Water: Its Purification and Use in the Industries</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Church's Laboratory Guide. Rewritten by Edward Kinch</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Clapham, J.&nbsp;H. Woolen and Worsted Industries</td><td class="catvolume">8vo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Clapperton, G. Practical Papermaking</td><td class="catvolume">8vo,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">Clark, A.&nbsp;G. Motor Car Engineering.</td><td class="catvolume">&nbsp;</td><td class="catprice">&nbsp;</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. I. Construction</td><td class="catvolume">&nbsp;</td><td class="catprice">*3 00</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. II. Design</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Clark, C.&nbsp;H. Marine Gas Engines</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Clark, J.&nbsp;M. New System of Laying Out Railway Turnouts</td><td class="catvolume">12mo,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">Clarke, J.&nbsp;W., and Scott, W. Plumbing Practice.</td><td class="catvolume">&nbsp;</td><td class="catprice">&nbsp;</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. I. Lead Working and Plumbers' Materials</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. II. Sanitary Plumbing and Fittings</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. III. Practical Lead Working on Roofs</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Clarkson, R.&nbsp;B. Elementary Electrical Engineering</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Clausen-Thue, W. A B C Universal Commercial Telegraphic Code.
+  Sixth Edition</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Clerk, D., and Idell, F.&nbsp;E. Theory of the Gas Engine. (Science Series
+No. 62.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Clevenger, S.&nbsp;R. Treatise on the Method of Government Surveying.</td><td class="catvolume">16mo, morocco,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">Clouth, F. Rubber, Gutta-Percha, and Balata</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Cochran, J. Concrete and Reinforced Concrete Specifications</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Inspection of Concrete Construction</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Treatise on Cement Specifications</td><td class="catvolume">8vo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Cocking, W.&nbsp;C. Calculations for Steel-Frame Structures</td><td class="catvolume">12mo,</td><td class="catprice">*2 25</td></tr>
+
+<tr><td class="catent">Coffin, J.&nbsp;H.&nbsp;C. Navigation and Nautical Astronomy</td><td class="catvolume">12mo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Colburn, Z., and Thurston, R.&nbsp;H. Steam Boiler Explosions. (Science
+  Series No. 2.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Cole, R.&nbsp;S. Treatise on Photographic Optics</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Coles-Finch, W. Water, Its Origin and Use</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Collins, J.&nbsp;E. Useful Alloys and Memoranda for Goldsmiths, Jewelers.</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Collis, A.&nbsp;G. High and Low Tension Switch-Gear Design</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Switchgear. (Installation Manuals Series.)</td><td class="catvolume">12mo,</td><td class="catprice">*0 50</td></tr>
+
+<tr><td class="catent">Comstock, D.&nbsp;F., and Troland, L.&nbsp;T. The Nature of Electricity and
+  Matter</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Coombs, H.&nbsp;A. Gear Teeth. (Science Series No. 120.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Cooper, W.&nbsp;R. Primary Batteries</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Copperthwaite, W.&nbsp;C. Tunnel Shields</td><td class="catvolume">4to,</td><td class="catprice">*9 00</td></tr>
+
+<tr><td class="catent">Corfield, W.&nbsp;H. Dwelling Houses. (Science Series No. 50.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Water and Water-Supply. (Science Series No. 17.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Cornwall, H.&nbsp;B. Manual of Blow-pipe Analysis</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Cowee, G.&nbsp;A. Practical Safety Methods and Devices</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Cowell, W.&nbsp;B. Pure Air, Ozone, and Water</td><td class="catvolume">12mo,</td><td class="catprice">*2 00<span class='pagenum'><a name="Page_8a" id="Page_8a">[8]</a></span></td></tr>
+
+<tr><td class="catent">Craig, J.&nbsp;W., and Woodward, W.&nbsp;P. Questions and Answers About
+  Electrical Apparatus</td><td class="catvolume">12mo, leather,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Craig, T. Motion of a Solid in a Fuel. (Science Series No. 49.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Wave and Vortex Motion. (Science Series No. 43.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Cramp, W. Continuous Current Machine Design</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Crehore, A.&nbsp;C. Mystery of Matter and Energy</td><td class="catvolume">8vo,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">Creedy, F. Single Phase Commutator Motors</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Crocker, F.&nbsp;B. Electric Lighting. Two Volumes.</td><td class="catvolume">8vo.</td><td class="catprice">&nbsp;</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. I. The Generating Plant</td><td class="catvolume">&nbsp;</td><td class="catprice">3 00</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. II. Distributing Systems and Lamps</td><td class="catvolume">&nbsp;</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Crocker, F.&nbsp;B., and Arendt, M. Electric Motors</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Crocker, F.&nbsp;B., and Wheeler, S.&nbsp;S. The Management of Electrical Machinery</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Cross, C.&nbsp;F., Bevan, E.&nbsp;J., and Sindall, R.&nbsp;W. Wood Pulp and Its Applications.
+(Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Crosskey, L.&nbsp;R. Elementary Perspective</td><td class="catvolume">8vo,</td><td class="catprice">1 25</td></tr>
+
+<tr><td class="catent">Crosskey, L.&nbsp;R., and Thaw, J. Advanced Perspective</td><td class="catvolume">8vo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Culley, J.&nbsp;L. Theory of Arches. (Science Series No. 87.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Cushing, H.&nbsp;C., Jr., and Harrison, N. Central Station Management</td><td class="catvolume">&nbsp;</td><td class="catprice">*2 00</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Dadourian, H.&nbsp;M. Analytical Mechanics</td><td class="catvolume">12mo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Dana, R.&nbsp;T. Handbook of Construction plant</td><td class="catvolume">12mo, leather,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Danby, A. Natural Rock Asphalts and Bitumens</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Davenport, C. The Book. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Davey, N. The Gas Turbine</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Davies, F.&nbsp;H. Electric Power and Traction</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Foundations and Machinery Fixing. (Installation Manual Series.)</td><td class="catvolume">16mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Deerr, N. Sugar Cane</td><td class="catvolume">8vo,</td><td class="catprice">8 00</td></tr>
+
+<tr><td class="catent">Deite, C. Manual of Soapmaking. Trans. by S.&nbsp;T. King</td><td class="catvolume">4to,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">De la Coux, H. The Industrial Uses of Water. Trans. by A. Morris.</td><td class="catvolume">8vo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">Del Mar, W.&nbsp;A. Electric Power Conductors</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Denny, G.&nbsp;A. Deep-level Mines of the Rand</td><td class="catvolume">4to,</td><td class="catprice">*10 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Diamond Drilling for Gold</td><td class="catvolume">&nbsp;</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">De Roos, J.&nbsp;D.&nbsp;C. Linkages. (Science Series No. 47.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Derr, W.&nbsp;L. Block Signal Operation</td><td class="catvolume">Oblong 12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Maintenance-of-Way Engineering</td><td class="catvolume">(<i>In Preparation.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Desaint, A. Three Hundred Shades and How to Mix Them</td><td class="catvolume">8vo,</td><td class="catprice">*8 00</td></tr>
+
+<tr><td class="catent">De Varona, A. Sewer Gases. (Science Series No. 55.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Devey, R.&nbsp;G. Mill and Factory Wiring. (Installation Manuals Series.)</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Dibdin, W.&nbsp;J. Purification of Sewage and Water</td><td class="catvolume">8vo,</td><td class="catprice">6 50</td></tr>
+
+<tr><td class="catent">Dichmann, Carl. Basic Open-Hearth Steel Process</td><td class="catvolume">12mo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Dieterich, K. Analysis of Resins, Balsams, and Gum Resins</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Dilworth, E.&nbsp;C. Steel Railway Bridges</td><td class="catvolume">4to,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Dinger, Lieut. H.&nbsp;C. Care and Operation of Naval Machinery</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Dixon, D.&nbsp;B. Machinist's and Steam Engineer's Practical Calculator.</td><td class="catvolume">16mo, morocco,</td><td class="catprice">1 25</td></tr>
+
+<tr><td class="catent">Dodge, G.&nbsp;F. Diagrams for Designing Reinforced Concrete Structures,</td><td class="catvolume">folio,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Dommett, W.&nbsp;E. Motor Car Mechanism</td><td class="catvolume">12mo,</td><td class="catprice">*1 50<span class='pagenum'><a name="Page_9a" id="Page_9a">[9]</a></span></td></tr>
+
+<tr><td class="catent">Dorr, B.&nbsp;F. The Surveyor's Guide and Pocket Table-book.</td><td class="catvolume">16mo, morocco,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Draper, C.&nbsp;H. Elementary Text-book of Light, Heat and Sound</td><td class="catvolume">12mo,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Heat and the Principles of Thermo-dynamics</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Dron, R.&nbsp;W. Mining Formulas</td><td class="catvolume">12mo,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">Dubbel, H. High Power Gas Engines</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Dumesny, P., and Noyer, J. Wood Products, Distillates, and Extracts.</td><td class="catvolume">8vo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">Duncan, W.&nbsp;G., and Penman, D. The Electrical Equipment of Collieries.</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Dunkley, W.&nbsp;G. Design of Machine Elements</td><td class="catvolume">8vo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Dunstan, A.&nbsp;E., and Thole, F.&nbsp;B.&nbsp;T. Textbook of Practical Chemistry.</td><td class="catvolume">12mo,</td><td class="catprice">*1 40</td></tr>
+
+<tr><td class="catent">Durham, H.&nbsp;W. Saws</td><td class="catvolume">8vo,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">Duthie, A.&nbsp;L. Decorative Glass Processes. (Westminster Series.).</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Dwight, H.&nbsp;B. Transmission Line Formulas</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Dyson, S.&nbsp;S. Practical Testing of Raw Materials</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Dyson, S.&nbsp;S., and Clarkson, S.&nbsp;S. Chemical Works</td><td class="catvolume">8vo,</td><td class="catprice">*7 50</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Eccles, W.&nbsp;H. Wireless Telegraphy and Telephony</td><td class="catvolume">12mo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">Eck, J. Light, Radiation and Illumination. Trans. by Paul Hogner,</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Eddy, H.&nbsp;T. Maximum Stresses under Concentrated Loads</td><td class="catvolume">8vo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Eddy, L.&nbsp;C. Laboratory Manual of Alternating Currents</td><td class="catvolume">12mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Edelman, P. Inventions and Patents</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Edgcumbe, K. Industrial Electrical Measuring Instruments</td><td class="catvolume">8vo, (<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Edler, R. Switches and Switchgear. Trans. by Ph. Laubach</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
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+<tr><td class="catent">Eissler, M. The Metallurgy of Gold</td><td class="catvolume">8vo,</td><td class="catprice">7 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; The Metallurgy of Silver</td><td class="catvolume">8vo,</td><td class="catprice">4 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; The Metallurgy of Argentiferous Lead</td><td class="catvolume">8vo,</td><td class="catprice">5 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; A Handbook on Modern Explosives</td><td class="catvolume">8vo,</td><td class="catprice">5 00</td></tr>
+
+<tr><td class="catent">Ekin, T.&nbsp;C. Water Pipe and Sewage Discharge Diagrams</td><td class="catvolume">folio,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Electric Light Carbons, Manufacture of</td><td class="catvolume">8vo,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">Eliot, C.&nbsp;W., and Storer, F.&nbsp;H. Compendious Manual of Qualitative
+Chemical Analysis</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Ellis, C. Hydrogenation of Oils</td><td class="catvolume">8vo, (<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Ellis, G. Modern Technical Drawing</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Ennis, Wm. D. Linseed Oil and Other Seed Oils</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Applied Thermodynamics</td><td class="catvolume">8vo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Flying Machines To-day</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Vapors for Heat Engines</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Ermen, W.&nbsp;F.&nbsp;A. Materials Used in Sizing</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Erwin, M. The Universe and the Atom</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Evans, C.&nbsp;A. Macadamized Roads</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Ewing, A.&nbsp;J. Magnetic Induction in Iron</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Fairie, J. Notes on Lead Ores</td><td class="catvolume">12mo,</td><td class="catprice">*0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Notes on Pottery Clays</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Fairley, W., and Andre, Geo. J. Ventilation of Coal
+  Mines. (Science Series No. 58.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50<span class='pagenum'><a name="Page_10a" id="Page_10a">[10]</a></span></td></tr>
+
+<tr><td class="catent">Fairweather, W.&nbsp;C. Foreign and Colonial Patent Laws</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Falk, M.&nbsp;S. Cement Mortars and Concretes</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Fanning, J.&nbsp;T. Hydraulic and Water-supply Engineering</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Fay, I.&nbsp;W. The Coal-tar Colors</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Fernbach, R.&nbsp;L. Glue and Gelatine</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Firth, J.&nbsp;B. Practical Physical Chemistry</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Fischer, E. The Preparation of Organic Compounds.
+  Trans. by R.&nbsp;V. Stanford</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Fish, J.&nbsp;C.&nbsp;L. Lettering of Working Drawings</td><td class="catvolume">Oblong 8vo,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Mathematics of the Paper Location of a Railroad
+   paper</td><td class="catvolume">12mo,</td><td class="catprice">*0 25</td></tr>
+
+<tr><td class="catent">Fisher, H.&nbsp;K.&nbsp;C., and Darby, W.&nbsp;C. Submarine Cable
+  Testing</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Fleischmann, W. The Book of the Dairy. Trans. by
+  C.&nbsp;M. Aikman</td><td class="catvolume">8vo,</td><td class="catprice">4 00</td></tr>
+
+<tr><td class="catent">Fleming, J.&nbsp;A. The Alternate-current Transformer. Two Volumes.</td><td class="catvolume">8vo.</td><td class="catprice">&nbsp;</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. I. The Induction of Electric Currents</td><td class="catvolume">&nbsp;</td><td class="catprice">*5 00</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. II. The Utilization of Induced Currents</td><td class="catvolume">&nbsp;</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Propagation of Electric Currents</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; A Handbook for the Electrical Laboratory and
+  Testing Room. Two Volumes</td><td class="catvolume">8vo, each,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Fleury, P. Preparation and Uses of White Zinc Paints</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Flynn, P.&nbsp;J. Flow of Water. (Science Series No. 84.)</td><td class="catvolume">12mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Hydraulic Tables. (Science Series No. 66.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Forgie, J. Shield Tunneling</td><td class="catvolume">8vo. (<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Foster, H.&nbsp;A. Electrical Engineers' Pocket-book.
+  (<i>Seventh Edition.</i>)</td><td class="catvolume">12mo, leather,</td><td class="catprice">5 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Engineering Valuation of Public Utilities and Factories</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Handbook of Electrical Cost Data</td><td class="catvolume">8vo (<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Fowle, F.&nbsp;F. Overhead Transmission Line Crossings</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; The Solution of Alternating Current Problems</td><td class="catvolume">8vo (<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Fox, W.&nbsp;G. Transition Curves. (Science Series No. 110.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Fox, W., and Thomas, C.&nbsp;W. Practical Course in
+Mechanical Drawing</td><td class="catvolume">12mo,</td><td class="catprice">1 25</td></tr>
+
+<tr><td class="catent">Foye, J.&nbsp;C. Chemical Problems.
+  (Science Series No. 69.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Handbook of Mineralogy. (Science Series No. 86.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Francis, J.&nbsp;B. Lowell Hydraulic Experiments</td><td class="catvolume">4to,</td><td class="catprice">15 00</td></tr>
+
+<tr><td class="catent">Franzen, H. Exercises in Gas Analysis</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Freudemacher, P.&nbsp;W. Electrical Mining Installations.
+  (Installation Manuals Series.)</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Frith, J. Alternating Current Design</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Fritsch, J. Manufacture of Chemical Manures. Trans.
+  by D. Grant.</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Frye, A.&nbsp;I. Civil Engineers' Pocket-book</td><td class="catvolume">12mo, leather,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Fuller, G.&nbsp;W. Investigations into the Purification of
+  the Ohio River</td><td class="catvolume">4to,</td><td class="catprice">*10 00</td></tr>
+
+<tr><td class="catent">Furnell, J. Paints, Colors, Oils, and Varnishes</td><td class="catvolume">8vo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Gairdner, J.&nbsp;W.&nbsp;I. Earthwork</td><td class="catvolume">8vo (<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Gant, L.&nbsp;W. Elements of Electric Traction</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Garcia, A.&nbsp;J.&nbsp;R.&nbsp;V. Spanish-English Railway Terms</td><td class="catvolume">8vo,</td><td class="catprice">*4 50<span class='pagenum'><a name="Page_11a" id="Page_11a">[11]</a></span></td></tr>
+
+<tr><td class="catent">Gardner, H.&nbsp;A. Paint Researches, and Their Practical
+  Applications</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Garforth, W.&nbsp;E. Rules for Recovering Coal Mines after
+  Explosions and Fires</td><td class="catvolume">12mo, leather,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Garrard, C.&nbsp;C. Electric Switch and Controlling Gear</td><td class="catvolume">8vo,</td><td class="catprice">*6 00</td></tr>
+
+<tr><td class="catent">Gaudard, J. Foundations. (Science Series No. 34.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Gear, H.&nbsp;B., and Williams, P.&nbsp;F. Electric Central
+  Station Distribution Systems</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Geerligs, H.&nbsp;C.&nbsp;P. Cane Sugar and Its Manufacture</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Geikie, J. Structural and Field Geology</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Mountains. Their Growth, Origin and Decay</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; The Antiquity of Man in Europe</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Georgi, F., and Schubert, A. Sheet Metal Working.
+  Trans. by C. Salter</td><td class="catvolume">8vo,</td><td class="catprice">3 00</td></tr>
+
+<tr><td class="catent">Gerhard, W.&nbsp;P. Sanitation, Watersupply and Sewage
+  Disposal of Country Houses</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Gas Lighting  (Science Series No. 111.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Household Wastes. (Science Series No. 97.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; House Drainage. (Science Series No. 63.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Sanitary Drainage of Buildings. (Science Series
+  No. 93.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Gerhardi, C.&nbsp;W.&nbsp;H. Electricity Meters</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Geschwind, L. Manufacture of Alum and Sulphates.
+  Trans. by C. Salter</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Gibbings, A.&nbsp;H. Oil Fuel Equipment for Locomotives</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Gibbs, W.&nbsp;E. Lighting by Acetylene</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Gibson, A.&nbsp;H. Hydraulics and Its Application</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Water Hammer in Hydraulic Pipe Lines</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Gibson, A.&nbsp;H., and Ritchie, E.&nbsp;G. Circular
+  Arc Bow Girder</td><td class="catvolume">4to,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Gilbreth, F.&nbsp;B. Motion Study</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Bricklaying System</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Field System</td><td class="catvolume">12mo, leather,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Primer of Scientific Management</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Gillette, H.&nbsp;P. Handbook of Cost Data</td><td class="catvolume">12mo, leather,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Rock Excavation Methods and Cost</td><td class="catvolume">12mo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; and Dana, R.&nbsp;T. Cost Keeping and Management
+  Engineering</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; and Hill, C.&nbsp;S. Concrete Construction, Methods
+  and Cost</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Gillmore, Gen. Q.&nbsp;A. Roads, Streets, and Pavements</td><td class="catvolume">12mo,</td><td class="catprice">1 25</td></tr>
+
+<tr><td class="catent">Godfrey, E. Tables for Structural Engineers</td><td class="catvolume">16mo, leather,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Golding, H.&nbsp;A. The Theta-Phi Diagram</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Goldschmidt, R. Alternating Current Commutator Motor</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Goodchild, W. Precious Stones. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Goodeve, T.&nbsp;M. Textbook on the Steam-engine</td><td class="catvolume">12mo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Gore, G. Electrolytic Separation of Metals</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Gould, E.&nbsp;S. Arithmetic of the Steam-engine</td><td class="catvolume">12mo,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Calculus. (Science Series No. 112.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; High Masonry Dams. (Science Series No. 22.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Gould, E.&nbsp;S. Practical Hydrostatics and Hydrostatic
+Formulas. (Science Series No. 117.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50<span class='pagenum'><a name="Page_12a" id="Page_12a">[12]</a></span></td></tr>
+
+<tr><td class="catent">Gratacap, L.&nbsp;P. A Popular Guide to Minerals</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Gray, J. Electrical Influence Machines</td><td class="catvolume">12mo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Marine Boiler Design</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Greenhill, G. Dynamics of Mechanical Flight</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Gregorius, R. Mineral Waxes. Trans. by C. Salter</td><td class="catvolume">12mo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Grierson, R. Some Modern Methods of Ventilation</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Griffiths, A.&nbsp;B. A Treatise on Manures</td><td class="catvolume">12mo,</td><td class="catprice">3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Dental Metallurgy</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Gross, E. Hops</td><td class="catvolume">8vo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">Grossman, J. Ammonia and Its Compounds</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Groth, L.&nbsp;A. Welding and Cutting Metals by Gases or
+  Electricity. (Westminster Series)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Grover, F. Modern Gas and Oil Engines</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Gruner, A. Power-loom Weaving</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">G&uuml;ldner, Hugo. Internal Combustion Engines. Trans.
+  by H. Diederichs</td><td class="catvolume">4to,</td><td class="catprice">*15 00</td></tr>
+
+<tr><td class="catent">Gunther, C.&nbsp;O. Integration</td><td class="catvolume">8vo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Gurden, R.&nbsp;L. Traverse Tables</td><td class="catvolume">folio, half morocco,</td><td class="catprice">*7 50</td></tr>
+
+<tr><td class="catent">Guy, A.&nbsp;E. Experiments on the Flexure of Beams</td><td class="catvolume">8vo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Haenig, A. Emery and Emery Industry</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Hainbach, R. Pottery Decoration. Trans. by C. Salter</td><td class="catvolume">12mo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Hale, W.&nbsp;J. Calculations of General Chemistry</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Hall, C.&nbsp;H. Chemistry of Paints and Paint Vehicles</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Hall, G.&nbsp;L. Elementary Theory of Alternate Current
+  Working</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Hall, R.&nbsp;H. Governors and Governing Mechanism</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Hall, W.&nbsp;S. Elements of the Differential and Integral
+  Calculus</td><td class="catvolume">8vo,</td><td class="catprice">*2 25</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Descriptive Geometry</td><td class="catvolume">8vo volume and a 4to atlas,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Haller, G.&nbsp;F., and Cunningham, E.&nbsp;T. The Tesla Coil</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Halsey, F.&nbsp;A. Slide Valve Gears</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; The Use of the Slide Rule. (Science Series No.
+  114.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Worm and Spiral Gearing. (Science Series No.
+  116.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Hancock, H. Textbook of Mechanics and Hydrostatics</td><td class="catvolume">8vo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Hancock, W.&nbsp;C. Refractory Materials. (Metallurgy
+  Series.)</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Hardy, E. Elementary Principles of Graphic Statics</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Haring, H. Engineering Law
+  Vol. I. Law of Contract</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Harper, J.&nbsp;H. Hydraulic Tables on the Flow of Water</td><td class="catvolume">16mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Harris, S.&nbsp;M. Practical Topographical Surveying</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Harrison, W.&nbsp;B. The Mechanics' Tool-book</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Hart, J.&nbsp;W. External Plumbing Work</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Hints to Plumbers on Joint Wiping</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Principles of Hot Water Supply</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Sanitary Plumbing and Drainage</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Haskins, C.&nbsp;H. The Galvanometer and Its Uses</td><td class="catvolume">16mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Hatt, J.&nbsp;A.&nbsp;H. The Colorist</td><td class="catvolume">square 12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Hausbrand, E. Drying by Means of Air and Steam.
+  Trans. by A.&nbsp;C. Wright</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Evaporating, Condensing and Cooling Apparatus.
+  Trans. by A.&nbsp;C. Wright</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Hausmann, E. Telegraph Engineering</td><td class="catvolume">8vo,</td><td class="catprice">*3 00<span class='pagenum'><a name="Page_13a" id="Page_13a">[13]</a></span></td></tr>
+
+<tr><td class="catent">Hausner, A. Manufacture of Preserved Foods and
+  Sweetmeats. Trans. by A. Morris and H. Robson</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Hawkesworth, J. Graphical Handbook for Reinforced
+Concrete Design.</td><td class="catvolume">4to,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Hay, A. Continuous Current Engineering</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Hayes, H.&nbsp;V. Public Utilities, Their Cost New and
+  Depreciation</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Public Utilities, Their Fair Present Value and
+  Return</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Heath, F.&nbsp;H. Chemistry of Photography</td><td class="catvolume">8vo. (<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Heather, H.&nbsp;J.&nbsp;S. Electrical Engineering</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Heaviside, O. Electromagnetic Theory. Vols. I and II</td><td class="catvolume">8vo, each,</td><td class="catprice">*5 00</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. III</td><td class="catvolume">8vo,</td><td class="catprice">*7 50</td></tr>
+
+<tr><td class="catent">Heck, R.&nbsp;C.&nbsp;H. The Steam Engine and Turbine</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Steam-Engine and Other Steam Motors. Two Volumes.</td><td class="catvolume">&nbsp;</td><td class="catprice">&nbsp;</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. I. Thermodynamics and the Mechanics</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. II. Form, Construction, and Working</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Notes on Elementary Kinematics</td><td class="catvolume">8vo, boards,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Graphics of Machine Forces</td><td class="catvolume">8vo, boards,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Heermann, P. Dyers' Materials. Trans. by A.&nbsp;C.
+  Wright</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Heidenreich, E.&nbsp;L. Engineers' Pocketbook of Reinforced
+  Concrete</td><td class="catvolume">16mo, leather,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Hellot, Macquer and D'Apligny. Art of Dyeing Wool, Silk
+  and Cotton</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Henrici, O. Skeleton Structures</td><td class="catvolume">8vo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Hering, C., and Getman, F.&nbsp;H. Standard Tables of Electro-Chemical
+Equivalents</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Hering, D.&nbsp;W. Essentials of Physics for College
+  Students</td><td class="catvolume">8vo,</td><td class="catprice">*1 75</td></tr>
+
+<tr><td class="catent">Hering-Shaw, A. Domestic Sanitation and Plumbing.
+  Two Vols.</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Hering-Shaw, A. Elementary Science</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Herington, C.&nbsp;F. Powdered Coal and Fuel</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Herrmann, G. The Graphical Statics of Mechanism.
+  Trans. by A.&nbsp;P. Smith</td><td class="catvolume">12mo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Herzfeld, J. Testing of Yarns and Textile Fabrics</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Hildebrandt, A. Airships, Past and Present</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Hildenbrand, B.&nbsp;W. Cable-Making. (Science Series No.
+  32.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Hilditch, T.&nbsp;P. A Concise History of Chemistry</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Hill, C.&nbsp;S. Concrete Inspection</td><td class="catvolume">16mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Hill, J.&nbsp;W. The Purification of Public Water Supplies.
+  New Edition</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Interpretation of Water Analysis</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Hill, M.&nbsp;J.&nbsp;M. The Theory of Proportion</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Hiroi, I. Plate Girder Construction. (Science Series
+  No. 95.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Statically-Indeterminate Stresses</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Hirshfeld, C.&nbsp;F. Engineering Thermodynamics. (Science
+  Series No. 45.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Hoar, A. The Submarine Torpedo Boat</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Hobart, H.&nbsp;M. Heavy Electrical Engineering</td><td class="catvolume">8vo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Design of Static Transformers</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Electricity</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Electric Trains</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Electric Propulsion of Ships</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Hobart, J.&nbsp;F. Hard Soldering, Soft Soldering and Brazing.</td><td class="catvolume">12mo,</td><td class="catprice">*1 00<span class='pagenum'><a name="Page_14a" id="Page_14a">[14]</a></span></td></tr>
+
+<tr><td class="catent">Hobbs, W.&nbsp;R.&nbsp;P. The Arithmetic of Electrical Measurements.</td><td class="catvolume">12mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Hoff, J.&nbsp;N. Paint and Varnish Facts and Formulas.</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Hole, W. The Distribution of Gas.</td><td class="catvolume">8vo,</td><td class="catprice">*7 50</td></tr>
+
+<tr><td class="catent">Holley, A.&nbsp;L. Railway Practice.</td><td class="catvolume">folio,</td><td class="catprice">6 00</td></tr>
+
+<tr><td class="catent">Hopkins, N.&nbsp;M. Model Engines and Small Boats.</td><td class="catvolume">12mo,</td><td class="catprice">1 25</td></tr>
+
+<tr><td class="catent">Hopkinson, J., Shoolbred, J.&nbsp;N., and Day, R.&nbsp;E. Dynamic Electricity. (Science Series No. 71.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Horner, J. Practical Ironfounding.</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Gear Cutting, in Theory and Practice.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Houghton, C.&nbsp;E. The Elements of Mechanics of Materials.</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Houstoun, R.&nbsp;A. Studies in Light Production.</td><td class="catvolume">12mo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Hovenden, F. Practical Mathematics for Young Engineers.</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Howe, G. Mathematics for the Practical Man.</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Howorth, J. Repairing and Riveting Glass, China and Earthenware.</td><td class="catvolume">8vo, paper,</td><td class="catprice">*0 50</td></tr>
+
+<tr><td class="catent">Hoyt, W.&nbsp;E. Chemistry by Experimentation.</td><td class="catvolume">8vo,</td><td class="catprice">*0 70</td></tr>
+
+<tr><td class="catent">Hubbard, E. The Utilization of Wood-waste.</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">H&uuml;bner, J. Bleaching and Dyeing of Vegetable and Fibrous Materials. (Outlines of Industrial Chemistry.)</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Hudson, O.&nbsp;F. Iron and Steel. (Outlines of Industrial Chemistry.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Humphrey, J.&nbsp;C.&nbsp;W. Metallography of Strain. (Metallurgy Series.)</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Humphreys, A.&nbsp;C. The Business Features of Engineering Practice.</td><td class="catvolume">8vo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Hunter, A. Bridge Work.</td><td class="catvolume">8vo. (<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Hurst. G.&nbsp;H. Handbook of the Theory of Color.</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Dictionary of Chemicals and Raw Products.</td><td class="catvolume">8vo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Lubricating Oils, Fats and Greases.</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Soaps.</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Hurst, G.&nbsp;H., and Simmons, W.&nbsp;H. Textile Soaps and Oils.</td><td class="catvolume">8vo,</td><td class="catprice">3 00</td></tr>
+
+<tr><td class="catent">Hurst, H.&nbsp;E., and Lattey, R.&nbsp;T. Text-book of Physics.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Also published in three parts.</td><td class="catvolume">&nbsp;</td><td class="catprice"></td></tr>
+<tr><td class="catent" style="padding-left: 4em">Part   I. Dynamics and Heat.</td><td class="catvolume">&nbsp;</td><td class="catprice">*1 25</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Part  II. Sound and Light.</td><td class="catvolume">&nbsp;</td><td class="catprice">*1 25</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Part III. Magnetism and Electricity.</td><td class="catvolume">&nbsp;</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Hutchinson, R.&nbsp;W., Jr. Long Distance Electric Power Transmission.</td><td class="catvolume">12mo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Hutchinson, R.&nbsp;W., Jr., and Thomas, W.&nbsp;A. Electricity in Mining.</td><td class="catvolume">12mo, (<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Hutchinson, W.&nbsp;B. Patents and How to Make Money Out of Them.</td><td class="catvolume">12mo,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">Hutton, W.&nbsp;S. The Works' Manager's Handbook.</td><td class="catvolume">8vo,</td><td class="catprice">6 00</td></tr>
+
+<tr><td class="catent">Hyde, E.&nbsp;W. Skew Arches. (Science Series No. 15.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Hyde, F.&nbsp;S. Solvents, Oils, Gums, Waxes.</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Induction Coils. (Science Series No. 53.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Ingham, A.&nbsp;E. Gearing. A practical treatise.</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Ingle, H. Manual of Agricultural Chemistry.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Inness, C.&nbsp;H. Problems in Machine Design.</td><td class="catvolume">12mo,</td><td class="catprice">*2 00<span class='pagenum'><a name="Page_15a" id="Page_15a">[15]</a></span></td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Air Compressors and Blowing Engines.</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Centrifugal Pumps.</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; The Fan.</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Jacob, A., and Gould, E.&nbsp;S. On the Designing and Construction of Storage Reservoirs. (Science Series No. 6)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Jannettaz, E. Guide to the Determination of Rocks. Trans. by G.&nbsp;W. Plympton.</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Jehl, F. Manufacture of Carbons.</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Jennings, A.&nbsp;S. Commercial Paints and Paintings. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Jennison, F.&nbsp;H. The Manufacture of Lake Pigments.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Jepson, G. Cams and the Principles of their Construction.</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Mechanical Drawing.</td><td class="catvolume">8vo. (<i>In Preparation.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Jervis-Smith, F.&nbsp;J. Dynamometers.</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Jockin, W. Arithmetic of the Gold and Silversmith.</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Johnson, J.&nbsp;H. Arc Lamps and Accessory Apparatus. (Installation Manuals Series.)</td><td class="catvolume">12mo,</td><td class="catprice">*0 75</td></tr>
+
+<tr><td class="catent">Johnson, T.&nbsp;M. Ship Wiring and Fitting. (Installation Manuals Series.)</td><td class="catvolume">12mo,</td><td class="catprice">*0 75</td></tr>
+
+<tr><td class="catent">Johnson, W. McA. The Metallurgy of Nickel.</td><td class="catvolume">(<i>In Preparation.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Johnston, J.&nbsp;F.&nbsp;W., and Cameron, C. Elements of Agricultural Chemistry and Geology.</td><td class="catvolume">12mo,</td><td class="catprice">2 60</td></tr>
+
+<tr><td class="catent">Joly, J. Radioactivity and Geology.</td><td class="catvolume">12mo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Jones, H.&nbsp;C. Electrical Nature of Matter and Radioactivity.</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Nature of Solution.</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; New Era in Chemistry.</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Jones, J.&nbsp;H. Tinplate Industry.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Jones, M.&nbsp;W. Testing Raw Materials Used in Paint.</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Jordan, L.&nbsp;C. Practical Railway Spiral.</td><td class="catvolume">12mo, leather,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Joynson, F.&nbsp;H. Designing and Construction of Machine Gearing.</td><td class="catvolume">8vo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">J&uuml;ptner, H.&nbsp;F.&nbsp;V. Siderology: The Science of Iron.</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Kapp, G. Alternate Current Machinery. (Science Series No. 96.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Kapper, F. Overhead Transmission Lines.</td><td class="catvolume">4to,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Keim, A.&nbsp;W. Prevention of Dampness in Buildings.</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Keller, S.&nbsp;S. Mathematics for Engineering Students.</td><td class="catvolume">12mo, half leather.</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; and Knox, W.&nbsp;E. Analytical Geometry and Calculus.</td><td class="catvolume">&nbsp;</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Kelsey, W.&nbsp;R. Continuous-current Dynamos and Motors.</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Kemble, W.&nbsp;T., and Underhill, C.&nbsp;R. The Periodic Law and the Hydrogen Spectrum.</td><td class="catvolume">8vo, paper,</td><td class="catprice">*0 50</td></tr>
+
+<tr><td class="catent">Kennedy, A.&nbsp;B.&nbsp;W., and Thurston, R.&nbsp;H. Kinematics of Machinery. (Science Series No. 54.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Kennedy, A.&nbsp;B.&nbsp;W., Unwin, W.&nbsp;C., and Idell, F.&nbsp;E. Compressed Air. (Science Series No. 106.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Kennedy, R. Electrical Installations. Five Volumes.</td><td class="catvolume">4to,</td><td class="catprice">15 00</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Single Volumes.</td><td class="catvolume">each,</td><td class="catprice">3 50<span class='pagenum'><a name="Page_16a" id="Page_16a">[16]</a></span></td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Flying Machines; Practice and Design.</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Principles of Aeroplane Construction.</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Kennelly, A.&nbsp;E. Electro-dynamic Machinery.</td><td class="catvolume">8vo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Kent, W. Strength of Materials. (Science Series No. 41.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Kershaw, J.&nbsp;B.&nbsp;C. Fuel, Water and Gas Analysis.</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Electrometallurgy. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; The Electric Furnace in Iron and Steel Production.</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Electro-Thermal Methods of Iron and Steel Production.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Kindelan, J. Trackman's Helper.</td><td class="catvolume">12mo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Kinzbrunner, C. Alternate Current Windings.</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Continuous Current Armatures.</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Testing of Alternating Current Machines.</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Kirkaldy, A.&nbsp;W., and Evans, A.&nbsp;D. History and Economics of Transport.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Kirkaldy, W.&nbsp;G. David Kirkaldy's System of Mechanical Testing.</td><td class="catvolume">4to,</td><td class="catprice">10 00</td></tr>
+
+<tr><td class="catent">Kirkbride, J. Engraving for Illustration.</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Kirkham, J.&nbsp;E. Structural Engineering.</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Kirkwood, J.&nbsp;P. Filtration of River Waters.</td><td class="catvolume">4to,</td><td class="catprice">7 50</td></tr>
+
+<tr><td class="catent">Kirschke, A. Gas and Oil Engines.</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Klein, J.&nbsp;F. Design of a High-speed Steam-engine.</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Physical Significance of Entropy.</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Klingenberg, G. Large Electric Power Stations.</td><td class="catvolume">4to,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Knight, R.-Adm. A.&nbsp;M. Modern Seamanship.</td><td class="catvolume">8vo,</td><td class="catprice">*6 50</td></tr>
+
+<tr><td class="catent">Knott, C.&nbsp;G., and Mackay, J.&nbsp;S. Practical Mathematics.</td><td class="catvolume">8vo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Knox, G.&nbsp;D. Spirit of the Soil.</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Knox, J. Physico-Chemical Calculations.</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Fixation of Atmospheric Nitrogen. (Chemical Monographs.)</td><td class="catvolume">12mo,</td><td class="catprice">*0 75</td></tr>
+
+<tr><td class="catent">Koester, F. Steam-Electric Power Plants.</td><td class="catvolume">4to,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Hydroelectric Developments and Engineering.</td><td class="catvolume">4to,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Koller, T. The Utilization of Waste Products.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Cosmetics.</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Koppe, S.&nbsp;W. Glycerine.</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Kozmin, P.&nbsp;A. Flour Milling. Trans. by M. Falkner.</td><td class="catvolume">8vo. (<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Kremann, R. Application of the Physico-Chemical Theory to Technical Processes and Manufacturing Methods. Trans. by H.&nbsp;E. Potts.</td><td class="catvolume">8vo, *3 00</td></tr>
+
+<tr><td class="catent">Kretchmar, K. Yarn and Warp Sizing.</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Lallier, E.&nbsp;V. Elementary Manual of the Steam Engine.</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Lambert, T. Lead and Its Compounds.</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Bone Products and Manures.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Lamborn, L.&nbsp;L. Cottonseed Products.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Modern Soaps, Candles, and Glycerin.</td><td class="catvolume">8vo,</td><td class="catprice">*7 50</td></tr>
+
+<tr><td class="catent">Lamprecht, R. Recovery Work After Pit Fires. Trans. by C. Salter.</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Lancaster, M. Electric Cooking, Heating and Cleaning.</td><td class="catvolume">8vo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Lanchester, F.&nbsp;W. Aerial Flight. Two Volumes.</td><td class="catvolume">8vo.</td><td class="catprice">&nbsp;</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. I. Aerodynamics.</td><td class="catvolume">&nbsp;</td><td class="catprice">*6 00</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. II. Aerodonetics.</td><td class="catvolume">&nbsp;</td><td class="catprice">*6 00</td></tr>
+
+<tr><td class="catent">Lanchester, F.&nbsp;W. The Flying Machine.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00<span class='pagenum'><a name="Page_17a" id="Page_17a">[17]</a></span></td></tr>
+
+<tr><td class="catent">Lange, K.&nbsp;R. By-Products of Coal-Gas Manufacture.</td><td class="catvolume">12mo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Larner, E.&nbsp;T. Principles of Alternating Currents.</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">La Rue, B.&nbsp;F. Swing Bridges. (Science Series No. 107.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Lassar-Cohn. Dr. Modern Scientific Chemistry. Trans. by M.&nbsp;M. Pattison Muir</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Latimer, L.&nbsp;H., Field, C.&nbsp;J., and Howell, J.&nbsp;W. Incandescent Electric Lighting. (Science Series No. 57.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Latta, M.&nbsp;N. Handbook of American Gas-Engineering Practice.</td><td class="catvolume">8vo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; American Producer Gas Practice.</td><td class="catvolume">4to,</td><td class="catprice">*6 00</td></tr>
+
+<tr><td class="catent">Laws, B.&nbsp;C. Stability and Equilibrium of Floating Bodies.</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Lawson, W.&nbsp;R. British Railways. A Financial and Commercial Survey.</td><td class="catvolume">8vo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Leask, A.&nbsp;R. Breakdowns at Sea.</td><td class="catvolume">12mo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Refrigerating Machinery.</td><td class="catvolume">12mo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Lecky, S.&nbsp;T.&nbsp;S. "Wrinkles" in Practical Navigation.</td><td class="catvolume">8vo,</td><td class="catprice">10 00</td></tr>
+
+<tr><td class="catent">Le Doux, M. Ice-Making Machines. (Science Series No. 46.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Leeds, C.&nbsp;C. Mechanical Drawing for Trade Schools.</td><td class="catvolume">oblong 4to,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Mechanical Drawing for High and Vocational Schools.</td><td class="catvolume">4to,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Lef&eacute;vre, L. Architectural Pottery. Trans. by H.&nbsp;K. Bird and W.&nbsp;M. Binns.</td><td class="catvolume">4to,</td><td class="catprice">*7 50</td></tr>
+
+<tr><td class="catent">Lehner, S. Ink Manufacture. Trans. by A. Morris and H. Robson.</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Lemstrom, S. Electricity in Agriculture and Horticulture.</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Letts, E.&nbsp;A. Fundamental Problems in Chemistry.</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Le Van, W.&nbsp;B. Steam-Engine Indicator. (Science Series No. 78.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Lewes, V.&nbsp;B. Liquid and Gaseous Fuels. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Carbonization of Coal.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Lewis, L.&nbsp;P. Railway Signal Engineering.</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Lewis Automatic Machine Rifle; Operation of.</td><td class="catvolume">16mo,</td><td class="catprice">*0 75</td></tr>
+
+<tr><td class="catent">Licks, H.&nbsp;E. Recreations in Mathematics.</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Lieber, B.&nbsp;F. Lieber's Five Letter Standard Telegraphic Code.</td><td class="catvolume">8vo,</td><td class="catprice">*10 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Code. German Edition.</td><td class="catvolume">8vo,</td><td class="catprice">*10 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; &mdash;&mdash; Spanish Edition.</td><td class="catvolume">8vo,</td><td class="catprice">*10 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; &mdash;&mdash; French Edition.</td><td class="catvolume">8vo,</td><td class="catprice">*10 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Terminal Index.</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Lieber's Appendix.</td><td class="catvolume">folio,</td><td class="catprice">*15 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; &mdash;&mdash; Handy Tables.</td><td class="catvolume">4to,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Bankers and Stockbrokers' Code and Merchants and Shippers' Blank Tables.</td><td class="catvolume">8vo,</td><td class="catprice">*15 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; 100,000,000 Combination Code.</td><td class="catvolume">8vo,</td><td class="catprice">*10 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Engineering Code.</td><td class="catvolume">8vo,</td><td class="catprice">*12 50</td></tr>
+
+<tr><td class="catent">Livermore, V.&nbsp;P., and Williams, J. How to Become a Competent Motorman</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Livingstone, R. Design and Construction of Commutators.</td><td class="catvolume">8vo,</td><td class="catprice">*2 25</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Mechanical Design and Construction of Generators.</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Lloyd, S.&nbsp;L. Fertilizer Materials.</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Lobben, P. Machinists' and Draftsmen's Handbook.</td><td class="catvolume">8vo,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">Lockwood, T.&nbsp;D. Electricity, Magnetism, and Electro-telegraph.</td><td class="catvolume">8vo,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Electrical Measurement and the Galvanometer.</td><td class="catvolume">12mo,</td><td class="catprice">0 75</td></tr>
+
+<tr><td class="catent">Lodge, O.&nbsp;J. Elementary Mechanics.</td><td class="catvolume">12mo,</td><td class="catprice">1 50<span class='pagenum'><a name="Page_18a" id="Page_18a">[18]</a></span></td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Signalling Across Space without Wires.</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Loewenstein, L.&nbsp;C., and Crissey, C.&nbsp;P. Centrifugal Pumps.</td><td class="catvolume">&nbsp;</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">Lomax, J.&nbsp;W. Cotton Spinning.</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Lord, R.&nbsp;T. Decorative and Fancy Fabrics.</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Loring, A.&nbsp;E. A Handbook of the Electromagnetic Telegraph.</td><td class="catvolume">16mo</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Handbook. (Science Series No. 39.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Lovell, D.&nbsp;H. Practical Switchwork.</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Low, D.&nbsp;A. Applied Mechanics (Elementary).</td><td class="catvolume">16mo,</td><td class="catprice">0 80</td></tr>
+
+<tr><td class="catent">Lubschez, B.&nbsp;J. Perspective.</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Lucke, C.&nbsp;E. Gas Engine Design.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Power Plants: Design, Efficiency, and Power Costs. 2 vols.</td><td class="catvolume">(<i>In Preparation.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Luckiesh, M. Color and Its Application.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Light and Shade and Their Applications.</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Lunge, G. Coal-tar and Ammonia. Three Volumes.</td><td class="catvolume">8vo,</td><td class="catprice">*20 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Technical Gas Analysis.</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Manufacture of Sulphuric Acid and Alkali. Four Volumes.</td><td class="catvolume">8vo,</td><td class="catprice">&nbsp;</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. I. Sulphuric Acid. In three parts.</td><td class="catvolume">&nbsp;</td><td class="catprice">18 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Vol. I. Supplement.</td><td class="catvolume">8vo,</td><td class="catprice">5 00</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. II. Salt Cake, Hydrochloric Acid and Leblanc Soda. In two parts.</td><td class="catvolume">&nbsp;</td><td class="catprice">*15 00</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. III. Ammonia Soda.</td><td class="catvolume">&nbsp;</td><td class="catprice">*10 00</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. IV. Electrolytic Methods.</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Technical Chemists' Handbook.</td><td class="catvolume">12mo, leather,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Technical Methods of Chemical Analysis. Trans. by C.&nbsp;A. Keane in collaboration with the corps of specialists.</td><td class="catvolume">&nbsp;</td><td class="catprice">&nbsp;</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. I. In two parts.</td><td class="catvolume">8vo,</td><td class="catprice">*15 00</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. II. In two parts.</td><td class="catvolume">8vo,</td><td class="catprice">*18 00</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. III. In two parts.</td><td class="catvolume">8vo,</td><td class="catprice">*18 00</td></tr>
+<tr><td class="catent" style="padding-left: 4em">The set (3 vols.) complete.</td><td class="catvolume">&nbsp;</td><td class="catprice">*50 00</td></tr>
+
+<tr><td class="catent">Luquer, L.&nbsp;M. Minerals in Rock Sections.</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Macewen, H.&nbsp;A. Food Inspection.</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Mackenzie, N.&nbsp;F. Notes on Irrigation Works.</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Mackie, J. How to Make a Woolen Mill Pay.</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Maguire, Wm. R. Domestic Sanitary Drainage and Plumbing.</td><td class="catvolume">8vo,</td><td class="catprice">4 00</td></tr>
+
+<tr><td class="catent">Malcolm, C.&nbsp;W. Textbook on Graphic Statics.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Malcolm, H.&nbsp;W. Submarine Telegraph Cable.</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Mallet, A. Compound Engines. Trans. by R.&nbsp;R. Buel. (Science Series No. 10.)</td><td class="catvolume">16mo,</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Mansfield, A.&nbsp;N. Electro-magnets. (Science Series No. 64.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Marks, E.&nbsp;C.&nbsp;R. Construction of Cranes and Lifting Machinery.</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Construction and Working of Pumps.</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Manufacture of Iron and Steel Tubes.</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Mechanical Engineering Materials.</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Marks, G.&nbsp;C. Hydraulic Power Engineering.</td><td class="catvolume">8vo,</td><td class="catprice">3 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Inventions, Patents and Designs.</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Marlow, T.&nbsp;G. Drying Machinery and Practice.</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Marsh, C.&nbsp;F. Concise Treatise on Reinforced Concrete.</td><td class="catvolume">8vo,</td><td class="catprice">*2 50<span class='pagenum'><a name="Page_19a" id="Page_19a">[19]</a></span></td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Reinforced Concrete Compression Member Diagram. Mounted on Cloth Boards.</td><td class="catvolume">&nbsp;</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Marsh, C.&nbsp;F., and Dunn, W. Manual of Reinforced Concrete and Concrete Block Construction.</td><td class="catvolume">16mo, morocco,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Marshall, W.&nbsp;J., and Sankey, H.&nbsp;R. Gas Engines. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Martin, G. Triumphs and Wonders of Modern Chemistry.</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Modern Chemistry and Its Wonders.</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Martin, N. Properties and Design of Reinforced Concrete.</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Martin, W.&nbsp;D. Hints to Engineers.</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Massie, W.&nbsp;W., and Underhill, C.&nbsp;R. Wireless Telegraphy and Telephony.</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Mathot, R.&nbsp;E. Internal Combustion Engines.</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Maurice, W. Electric Blasting Apparatus and Explosives.</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Shot Firer's Guide.</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Maxwell, J.&nbsp;C. Matter and Motion. (Science Series No. 36.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Maxwell, W.&nbsp;H., and Brown, J.&nbsp;T. Encyclopedia of Municipal and Sanitary Engineering.</td><td class="catvolume">4to,</td><td class="catprice">*10 00</td></tr>
+
+<tr><td class="catent">Mayer, A.&nbsp;M. Lecture Notes on Physics.</td><td class="catvolume">8vo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Mayer, C., and Slippy, J.&nbsp;C. Telephone Line Construction.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">McCullough, E. Practical Surveying.</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Engineering Work in Cities and Towns.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Reinforced Concrete.</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">McCullough, R.&nbsp;S. Mechanical Theory of Heat.</td><td class="catvolume">8vo,</td><td class="catprice">3 50</td></tr>
+
+<tr><td class="catent">McGibbon, W.&nbsp;C. Indicator Diagrams for Marine Engineers.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Marine Engineers' Drawing Book.</td><td class="catvolume">oblong 4to,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">McIntosh, J.&nbsp;G. Technology of Sugar.</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Industrial Alcohol.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Manufacture of Varnishes and Kindred Industries. Three Volumes.</td><td class="catvolume">8vo.</td><td class="catprice">&nbsp;</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. I. Oil Crushing, Refining and Boiling.</td><td class="catvolume">&nbsp;</td><td class="catprice">*3 50</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. II. Varnish Materials and Oil Varnish Making.</td><td class="catvolume">&nbsp;</td><td class="catprice">*4 00</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. III. Spirit Varnishes and Materials.</td><td class="catvolume">&nbsp;</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">McKnight, J.&nbsp;D., and Brown, A.&nbsp;W. Marine Multitubular Boilers.</td><td class="catvolume">&nbsp;</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">McMaster, J.&nbsp;B. Bridge and Tunnel Centres. (Science Series No. 20.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">McMechen, F.&nbsp;L. Tests for Ores, Minerals and Metals.</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">McPherson, J.&nbsp;A. Water-works Distribution.</td><td class="catvolume">8vo,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">Meade, A. Modern Gas Works Practice.</td><td class="catvolume">8vo,</td><td class="catprice">*7 50</td></tr>
+
+<tr><td class="catent">McGibbon, W.&nbsp;C. Marine Engineers Pocketbook.</td><td class="catvolume">12mo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Meade, R.&nbsp;K. Design and Equipment of Small Chemical Laboratories,</td><td class="catvolume">8vo,</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Melick, C.&nbsp;W. Dairy Laboratory Guide.</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Mensch, L.&nbsp;J. Reinforced Concrete Pocket Book.</td><td class="catvolume">16mo, leather,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Merck, E. Chemical Reagents; Their Purity and Tests. Trans. by H.&nbsp;E. Schenck.</td><td class="catvolume">8vo,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">Merivale, J.&nbsp;H. Notes and Formulae for Mining Students.</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Merritt, Wm. H. Field Testing for Gold and Silver.</td><td class="catvolume">16mo, leather,</td><td class="catprice">1 50<span class='pagenum'><a name="Page_20a" id="Page_20a">[20]</a></span></td></tr>
+
+<tr><td class="catent">Mierzinski, S. Waterproofing of Fabrics. Trans. by A. Morris and H. Robson.</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Miessner, B.&nbsp;F. Radio Dynamics.</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Miller, G.&nbsp;A. Determinants. (Science Series No. 105.)</td><td class="catvolume">16mo,</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Miller, W.&nbsp;J. Introduction to Historical Geology.</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Milroy, M.&nbsp;E.&nbsp;W. Home Lace-making.</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Mills, C.&nbsp;N. Elementary Mechanics for Engineers.</td><td class="catvolume">8vo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Mitchell, C.&nbsp;A. Mineral and Aerated Waters.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Mitchell, C.&nbsp;A., and Prideaux, R.&nbsp;M. Fibres Used in Textile and Allied Industries.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Mitchell, C.&nbsp;F., and G.&nbsp;A. Building Construction and Drawing.</td><td class="catvolume">12mo.</td><td class="catprice">&nbsp;</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Elementary Course.</td><td class="catvolume">&nbsp;</td><td class="catprice">*1 50</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Advanced Course.</td><td class="catvolume">&nbsp;</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Monckton, C.&nbsp;C.&nbsp;F. Radiotelegraphy. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Monteverde, R.&nbsp;D. Vest Pocket Glossary of English-Spanish, Spanish-English Technical Terms.</td><td class="catvolume">64mo, leather,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Montgomery, J.&nbsp;H. Electric Wiring Specifications.</td><td class="catvolume">16mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Moore, E.&nbsp;C.&nbsp;S. New Tables for the Complete Solution of Ganguillet and Kutter's Formula.</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Morecroft, J.&nbsp;H., and Hehre, F.&nbsp;W. Short Course in Electrical Testing.</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Morgan, A.&nbsp;P. Wireless Telegraph Apparatus for Amateurs.</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Moses, A.&nbsp;J. The Characters of Crystals.</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; and Parsons, C.&nbsp;L. Elements of Mineralogy.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Moss, S.&nbsp;A. Elements of Gas Engine Design. (Science Series No. 121.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; The Lay-out of Corliss Valve Gears. (Science Series No. 119.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Mulford, A.&nbsp;C. Boundaries and Landmarks.</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Mullin, J.&nbsp;P. Modern Moulding and Pattern-making.</td><td class="catvolume">12mo,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">Munby, A.&nbsp;E. Chemistry and Physics of Building Materials. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Murphy, J.&nbsp;G. Practical Mining.</td><td class="catvolume">16mo,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">Murray, J.&nbsp;A. Soils and Manures. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Nasmith, J. The Student's Cotton Spinning.</td><td class="catvolume">8vo,</td><td class="catprice">3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Recent Cotton Mill Construction.</td><td class="catvolume">12mo,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">Neave, G.&nbsp;B., and Heilbron, I.&nbsp;M. Identification of Organic Compounds.</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Neilson, R.&nbsp;M. Aeroplane Patents.</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Nerz, F. Searchlights. Trans. by C. Rodgers.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Neuberger, H., and Noalhat, H. Technology of Petroleum. Trans. by J.&nbsp;G. McIntosh.</td><td class="catvolume">8vo,</td><td class="catprice">*10 00</td></tr>
+
+<tr><td class="catent">Newall, J.&nbsp;W. Drawing, Sizing and Cutting Bevel-gears.</td><td class="catvolume">8vo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Newell, F.&nbsp;H., and Drayer, C.&nbsp;E. Engineering as a Career</td><td class="catvolume">12mo, cloth,</td><td class="catprice">*1 00</td></tr>
+<tr><td class="catent">&nbsp;</td><td class="catvolume">paper,</td><td class="catprice">0 75</td></tr>
+
+<tr><td class="catent">Newbeging, T. Handbook for Gas Engineers and Managers.</td><td class="catvolume">8vo,</td><td class="catprice">*6 50</td></tr>
+
+<tr><td class="catent">Nicol, G. Ship Construction and Calculations.</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Nipher, F.&nbsp;E. Theory of Magnetic Measurements.</td><td class="catvolume">12mo,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">Nisbet, H. Grammar of Textile Design</td><td class="catvolume">8vo,</td><td class="catprice">*3 00<span class='pagenum'><a name="Page_21a" id="Page_21a">[21]</a></span></td></tr>
+
+<tr><td class="catent">Nolan, H. The Telescope. (Science Series No. 51.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">North, H.&nbsp;B. Laboratory Experiments in General Chemistry</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Nugent, E. Treatise on Optics</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">O'Connor, H. The Gas Engineer's Pocketbook</td><td class="catvolume">12mo, leather,</td><td class="catprice">3 50</td></tr>
+
+<tr><td class="catent">Ohm, G.&nbsp;S., and Lockwood, T.&nbsp;D. Galvanic Circuit. Translated by
+William Francis. (Science Series No. 102.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Olsen, J.&nbsp;C. Text-book of Quantitative Chemical Analysis</td><td class="catvolume">8vo,</td><td class="catprice">3 50</td></tr>
+
+<tr><td class="catent">Olsson, A. Motor Control, in Turret Turning and Gun Elevating. (U.&nbsp;S.
+Navy Electrical Series, No. 1.)</td><td class="catvolume">12mo, paper,</td><td class="catprice">*0 50</td></tr>
+
+<tr><td class="catent">Ormsby, M.&nbsp;T.&nbsp;M. Surveying</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Oudin, M.&nbsp;A. Standard Polyphase Apparatus and Systems</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Owen, D. Recent Physical Research</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Pakes, W.&nbsp;C.&nbsp;C., and Nankivell, A.&nbsp;T. The Science of Hygiene</td><td class="catvolume">8vo,</td><td class="catprice">*1 75</td></tr>
+
+<tr><td class="catent">Palaz, A. Industrial Photometry. Trans. by G.&nbsp;W. Patterson, Jr.</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Pamely, C. Colliery Manager's Handbook</td><td class="catvolume">8vo,</td><td class="catprice">*10 00</td></tr>
+
+<tr><td class="catent">Parker, P.&nbsp;A.&nbsp;M. The Control of Water</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Parr, G.&nbsp;D.&nbsp;A. Electrical Engineering Measuring Instruments</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Parry, E.&nbsp;J. Chemistry of Essential Oils and Artificial Perfumes,</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Foods and Drugs. Two Volumes.</td><td class="catvolume">&nbsp;</td><td class="catprice">&nbsp;</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. I. Chemical and Microscopical Analysis of Foods and Drugs</td><td class="catvolume">&nbsp;</td><td class="catprice">*7 50</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. II. Sale of Food and Drugs Act</td><td class="catvolume">&nbsp;</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; and Coste, J.&nbsp;H. Chemistry of Pigments</td><td class="catvolume">8vo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">Parry, L. Notes on Alloys</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Metalliferous Wastes</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Analysis of Ashes and Alloys</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Parry, L.&nbsp;A. Risk and Dangers of Various Occupations</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Parshall, H.&nbsp;F., and Hobart, H.&nbsp;M. Armature Windings</td><td class="catvolume">4to,</td><td class="catprice">*7 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Electric Railway Engineering</td><td class="catvolume">4to,</td><td class="catprice">*10 00</td></tr>
+
+<tr><td class="catent">Parsons, J.&nbsp;L. Land Drainage</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Parsons, S.&nbsp;J. Malleable Cast Iron</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Partington, J.&nbsp;R. Higher Mathematics for Chemical Students</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Textbook of Thermodynamics</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Passmore, A.&nbsp;C. Technical Terms Used in Architecture</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Patchell, W.&nbsp;H. Electric Power in Mines</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Paterson, G.&nbsp;W.&nbsp;L. Wiring Calculations</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Electric Mine Signalling Installations</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Patterson, D. The Color Printing of Carpet Yarns</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Color Matching on Textiles</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Textile Color Mixing</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Paulding, C.&nbsp;P. Condensation of Steam in Covered and Bare Pipes</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Transmission of Heat through Cold-storage Insulation</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Payne, D.&nbsp;W. Iron Founders' Handbook</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Peckham, S.&nbsp;F. Solid Bitumens</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Peddie, R.&nbsp;A. Engineering and Metallurgical Books</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Peirce, B. System of Analytic Mechanics</td><td class="catvolume">4to,</td><td class="catprice">10 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Linnear Associative Algebra</td><td class="catvolume">4to,</td><td class="catprice">3 00</td></tr>
+
+<tr><td class="catent">Pendred, V. The Railway Locomotive. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Perkin, F.&nbsp;M. Practical Methods of Inorganic
+  Chemistry</td><td class="catvolume">12mo,</td><td class="catprice">*1 00<span class='pagenum'><a name="Page_22a" id="Page_22a">[22]</a></span></td></tr>
+
+<tr><td class="catent">Perrin, J. Atoms</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; and Jaggers, E.&nbsp;M. Elementary Chemistry</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Perrine, F.&nbsp;A.&nbsp;C. Conductors for Electrical
+  Distribution</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Petit, G. White Lead and Zinc White Paints</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Petit, R. How to Build an Aeroplane. Trans. by
+  T. O'B. Hubbard, and J.&nbsp;H. Ledeboer</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Pettit, Lieut. J.&nbsp;S. Graphic Processes. (Science
+  Series No. 76.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Philbrick, P.&nbsp;H. Beams and Girders. (Science Series
+  No. 88.)</td><td class="catvolume">16mo,</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Phillips, J. Gold Assaying</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Dangerous Goods</td><td class="catvolume">8vo,</td><td class="catprice">3 50</td></tr>
+
+<tr><td class="catent">Phin, J. Seven Follies of Science</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Pickworth, C.&nbsp;N. The Indicator Handbook. Two
+  Volumes</td><td class="catvolume">12mo, each,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Logarithms for Beginners</td><td class="catvolume">12mo, boards,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; The Slide Rule</td><td class="catvolume">12mo,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">Plattner's Manual of Blow-pipe Analysis. Eighth
+  Edition, revised. Trans. by H.&nbsp;B. Cornwall</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Plympton, G.&nbsp;W. The Aneroid Barometer. (Science
+  Series No. 35.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; How to become an Engineer. (Science Series No.
+  100.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Van Nostrand's Table Book,  (Science Series No.
+  104.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Pochet, M.&nbsp;L. Steam Injectors. Translated from the
+  French. (Science Series No. 29.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Pocket Logarithms to Four Places. (Science Series No.
+  65.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+<tr><td class="catent">&nbsp;</td><td class="catvolume">leather,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">Polleyn, F. Dressings and Finishings for Textile
+  Fabrics</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Pope, F.&nbsp;G. Organic Chemistry</td><td class="catvolume">12mo,</td><td class="catprice">*2 25</td></tr>
+
+<tr><td class="catent">Pope, F.&nbsp;L. Modern Practice of the Electric Telegraph</td><td class="catvolume">8vo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Popplewell, W.&nbsp;C. Prevention of Smoke</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Strength of Materials</td><td class="catvolume">8vo,</td><td class="catprice">*1 75</td></tr>
+
+<tr><td class="catent">Porritt, B.&nbsp;D. The Chemistry of Rubber. (Chemical
+  Monographs, No. 3.)</td><td class="catvolume">12mo,</td><td class="catprice">*0 75</td></tr>
+
+<tr><td class="catent">Porter, J.&nbsp;R. Helicopter Flying Machine</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Potts, H.&nbsp;E. Chemistry of the Rubber Industry.
+  (Outlines of Industrial Chemistry)</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Practical Compounding of Oils, Tallow and Grease</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Pratt, K. Boiler Draught</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; High Speed Steam Engines</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Pray, T., Jr. Twenty Years with the Indicator</td><td class="catvolume">8vo,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Steam Tables and Engine Constant</td><td class="catvolume">8vo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Prelini, C. Earth and Rock Excavation</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Graphical Determination of Earth Slopes</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Tunneling. New Edition</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Dredging. A Practical Treatise</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Prescott, A.&nbsp;B. Organic Analysis</td><td class="catvolume">8vo,</td><td class="catprice">5 00</td></tr>
+
+<tr><td class="catent">Prescott, A.&nbsp;B., and Johnson, O.&nbsp;C. Qualitative
+  Chemical Analysis</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Prescott, A.&nbsp;B., and Sullivan, E.&nbsp;C. First Book in
+  Qualitative Chemistry</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Prideaux, E.&nbsp;B.&nbsp;R. Problems in Physical Chemistry</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Primrose, G.&nbsp;S.&nbsp;C. Zinc. (Metallurgy Series.)</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Prince, G.&nbsp;T. Flow of Water</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Pullen, W.&nbsp;W.&nbsp;F. Application of Graphic Methods to
+  the Design of Structures</td><td class="catvolume">12mo,</td><td class="catprice">*2 50<span class='pagenum'><a name="Page_23a" id="Page_23a">[23]</a></span></td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Injectors: Theory, Construction and Working</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Indicator Diagrams</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Engine Testing</td><td class="catvolume">8vo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">Putsch, A. Gas and Coal-dust Firing</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Pynchon, T.&nbsp;R. Introduction to Chemical Physics</td><td class="catvolume">8vo,</td><td class="catprice">3 00</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Rafter G.&nbsp;W. Mechanics of Ventilation. (Science Series
+  No. 33.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Potable Water. (Science Series No. 103.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Treatment of Septic Sewage. (Science Series
+  No. 118.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Rafter, G.&nbsp;W., and Baker, M.&nbsp;N. Sewage Disposal in
+  the United States.</td><td class="catvolume">4to,</td><td class="catprice">*6 00</td></tr>
+
+<tr><td class="catent">Raikes, H.&nbsp;P. Sewage Disposal Works</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Randau, P. Enamels and Enamelling</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Rankine, W.&nbsp;J.&nbsp;M. Applied Mechanics</td><td class="catvolume">8vo,</td><td class="catprice">5 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Civil Engineering</td><td class="catvolume">8vo,</td><td class="catprice">6 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Machinery and Millwork</td><td class="catvolume">8vo,</td><td class="catprice">5 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; The Steam-engine and Other Prime Movers</td><td class="catvolume">8vo,</td><td class="catprice">5 00</td></tr>
+
+<tr><td class="catent">Rankine, W.&nbsp;J.&nbsp;M., and Bamber, E.&nbsp;F. A Mechanical
+  Text-book</td><td class="catvolume">8vo,</td><td class="catprice">3 50</td></tr>
+
+<tr><td class="catent">Ransome, W.&nbsp;R. Freshman Mathematics</td><td class="catvolume">12mo,</td><td class="catprice">*1 35</td></tr>
+
+<tr><td class="catent">Raphael, F.&nbsp;C. Localization of Faults in Electric
+  Light and Power Mains</td><td class="catvolume">8vo,</td><td class="catprice">3 50</td></tr>
+
+<tr><td class="catent">Rasch, E. Electric Arc Phenomena. Trans. by K. Tornberg</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Rateau, A. Flow of Steam through Nozzles and Orifices.
+  Trans. by H.&nbsp;B. Brydon</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Rathbone, R.&nbsp;L.&nbsp;B. Simple Jewellery</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Rausenberger, F. The Theory of the Recoil of Guns</td><td class="catvolume">8vo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">Rautenstrauch, W. Notes on the Elements of Machine
+  Design</td><td class="catvolume">8vo, boards,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Rautenstrauch, W., and Williams, J.&nbsp;T. Machine Drafting and Empirical Design.</td><td class="catvolume">&nbsp;</td><td class="catprice">&nbsp;</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Part I. Machine Drafting</td><td class="catvolume">8vo,</td><td class="catprice">*1 25</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Part II. Empirical Design</td><td class="catvolume">(<i>In Preparation.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Raymond, E.&nbsp;B. Alternating Current Engineering</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Rayner, H. Silk Throwing and Waste Silk Spinning</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Recipes for the Color, Paint, Varnish, Oil, Soap and
+  Drysaltery Trades</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Recipes for Flint Glass Making</td><td class="catvolume">12mo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">Redfern, J.&nbsp;B., and Savin, J. Bells, Telephones
+  (Installation Manuals Series.)</td><td class="catvolume">16mo,</td><td class="catprice">*0 50</td></tr>
+
+<tr><td class="catent">Redgrove, H.&nbsp;S. Experimental Mensuration</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Redwood, B. Petroleum. (Science Series No. 92.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Reed, S. Turbines Applied to Marine Propulsion</td><td class="catvolume">&nbsp;</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Reed's Engineers' Handbook</td><td class="catvolume">8vo,</td><td class="catprice">*6 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Key to the Nineteenth Edition of Reed's
+  Engineers' Handbook</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Useful Hints to Sea-going Engineers</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Reid, E.&nbsp;E. Introduction to Research in Organic
+  Chemistry</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Reid, H.&nbsp;A. Concrete and Reinforced Concrete
+  Construction</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Reinhardt, C.&nbsp;W. Lettering for Draftsmen, Engineers,
+  and Students</td><td class="catvolume">oblong 4to, boards,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">Reinhardt, C.&nbsp;W. The Technic of Mechanical Drafting,</td><td class="catvolume">oblong, 4to, boards,</td><td class="catprice">*1 00<span class='pagenum'><a name="Page_24a" id="Page_24a">[24]</a></span></td></tr>
+
+<tr><td class="catent">Reiser, F. Hardening and Tempering of Steel. Trans. by A. Morris and
+H. Robson</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Reiser, N. Faults in the Manufacture of Woolen Goods. Trans. by A.
+Morris and H. Robson</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Spinning and Weaving Calculations</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Renwick, W.&nbsp;G. Marble and Marble Working</td><td class="catvolume">8vo,</td><td class="catprice">5 00</td></tr>
+
+<tr><td class="catent">Reuleaux, F. The Constructor. Trans. by H.&nbsp;H. Suplee</td><td class="catvolume">4to,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Reuterdahl, A. Theory and Design of Reinforced Concrete Arches.</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Rey, Jean. The Range of Electric Searchlight Projectors</td><td class="catvolume">8vo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">Reynolds, O., and Idell, F.&nbsp;E. Triple Expansion Engines. (Science
+Series No. 99.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Rhead, G.&nbsp;F. Simple Structural Woodwork</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Rhodes, H.&nbsp;J. Art of Lithography</td><td class="catvolume">8vo,</td><td class="catprice">3 50</td></tr>
+
+<tr><td class="catent">Rice, J.&nbsp;M., and Johnson, W.&nbsp;W. A New Method of Obtaining the Differential
+of Functions</td><td class="catvolume">12mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Richards, W.&nbsp;A. Forging of Iron and Steel</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Richards, W.&nbsp;A., and North, H.&nbsp;B. Manual of Cement Testing</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Richardson, J. The Modern Steam Engine</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Richardson, S.&nbsp;S. Magnetism and Electricity</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Rideal, S. Glue and Glue Testing</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Rimmer, E.&nbsp;J. Boiler Explosions, Collapses and Mishaps</td><td class="catvolume">8vo,</td><td class="catprice">*1 75</td></tr>
+
+<tr><td class="catent">Rings, F. Concrete in Theory and Practice</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Reinforced Concrete Bridges</td><td class="catvolume">4to,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Ripper, W. Course of Instruction in Machine Drawing</td><td class="catvolume">folio,</td><td class="catprice">*6 00</td></tr>
+
+<tr><td class="catent">Roberts, F.&nbsp;C. Figure of the Earth. (Science Series No. 79.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Roberts, J., Jr. Laboratory Work in Electrical Engineering</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Robertson, L.&nbsp;S. Water-tube Boilers</td><td class="catvolume">8vo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Robinson, J.&nbsp;B. Architectural Composition</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Robinson, S.&nbsp;W. Practical Treatise on the Teeth of Wheels. (Science
+Series No. 24.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Railroad Economics. (Science Series No. 59.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Wrought Iron Bridge Members. (Science Series No. 60.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Robson, J.&nbsp;H. Machine Drawing and Sketching</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Roebling, J.&nbsp;A. Long and Short Span Railway Bridges</td><td class="catvolume">folio,</td><td class="catprice">25 00</td></tr>
+
+<tr><td class="catent">Rogers, A. A Laboratory Guide of Industrial Chemistry</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Elements of Industrial Chemistry</td><td class="catvolume">12mo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Manual of Industrial Chemistry</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Rogers, F. Magnetism of Iron Vessels. (Science Series No. 30.).</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Rohland, P. Colloidal and Crystalloidal State of Matter. Trans. by
+W.&nbsp;J. Britland and H.&nbsp;E. Potts</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Rollinson, C. Alphabets</td><td class="catvolume">Oblong, 12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Rose, J. The Pattern-makers' Assistant</td><td class="catvolume">8vo,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Key to Engines and Engine-running</td><td class="catvolume">12mo,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">Rose, T.&nbsp;K. The Precious Metals. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Rosenhain, W. Glass Manufacture. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Physical Metallurgy, An Introduction to. (Metallurgy Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Roth, W.&nbsp;A. Physical Chemistry</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Rowan, F.&nbsp;J. Practical Physics of the Modern Steam-boiler</td><td class="catvolume">8vo,</td><td class="catprice">*3 00<span class='pagenum'><a name="Page_25a" id="Page_25a">[25]</a></span></td></tr>
+
+<tr><td class="catent">&mdash;&mdash; and Idell, F.&nbsp;E. Boiler Incrustation and Corrosion. (Science
+Series No. 27.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Roxburgh, W. General Foundry Practice. (Westminster Series.).</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Ruhmer, E. Wireless Telephony. Trans. by J. Erskine-Murray.</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Russell, A. Theory of Electric Cables and Networks</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Rutley, F. Elements of Mineralogy</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Sanford, P.&nbsp;G. Nitro-explosives</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
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+<tr><td class="catent">Saunders, C.&nbsp;H. Handbook of Practical Mechanics</td><td class="catvolume">16mo,</td><td class="catprice">1 00</td></tr>
+<tr><td class="catent">&nbsp;</td><td class="catvolume">leather,</td><td class="catprice">1 25</td></tr>
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+<tr><td class="catent">Sayers, H.&nbsp;M. Brakes for Tram Cars</td><td class="catvolume">8vo,</td><td class="catprice">*1 25</td></tr>
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+<tr><td class="catent">Scheele, C.&nbsp;W. Chemical Essays</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
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+<tr><td class="catent">Scheithauer, W. Shale Oils and Tars</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
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+<tr><td class="catent">Scherer, R. Casein. Trans. by C. Salter</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
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+<tr><td class="catent">Schidrowitz, P. Rubber, Its Production and Industrial Uses</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
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+<tr><td class="catent">Schindler, K. Iron and Steel Construction Works</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
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+<tr><td class="catent">Schmall, C.&nbsp;N. First Course in Analytic Geometry, Plane and Solid.</td><td class="catvolume">12mo, half leather,</td><td class="catprice">*1 75</td></tr>
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+<tr><td class="catent">Schmeer, L. Flow of Water</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
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+<tr><td class="catent">Schumann, F. A Manual of Heating and Ventilation</td><td class="catvolume">12mo, leather,</td><td class="catprice">1 50</td></tr>
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+<tr><td class="catent">Schwarz, E.&nbsp;H.&nbsp;L. Causal Geology</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
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+<tr><td class="catent">Schweizer, V. Distillation of Resins</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
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+<tr><td class="catent">Scott, W.&nbsp;W. Qualitative Analysis. A Laboratory Manual</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
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+<tr><td class="catent">&mdash;&mdash; Standard Methods of Chemical Analysis</td><td class="catvolume">8vo,</td><td class="catprice">*6 00</td></tr>
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+<tr><td class="catent">Scribner, J.&nbsp;M. Engineers' and Mechanics' Companion</td><td class="catvolume">16mo, leather,</td><td class="catprice">1 50</td></tr>
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+<tr><td class="catent">Scudder, H. Electrical Conductivity and Ionization Constants of
+Organic Compounds</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Searle, A.&nbsp;B. Modern Brickmaking</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
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+<tr><td class="catent">&mdash;&mdash; Cement, Concrete and Bricks</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Searle, G.&nbsp;M. "Sumners' Method."  Condensed and Improved.
+(Science Series No. 124.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Seaton, A.&nbsp;E. Manual of Marine Engineering</td><td class="catvolume">8vo,</td><td class="catprice">8 00</td></tr>
+
+<tr><td class="catent">Seaton, A.&nbsp;E., and Rounthwaite, H.&nbsp;M. Pocket-book of Marine Engineering</td><td class="catvolume">16mo, leather,</td><td class="catprice">3 50</td></tr>
+
+<tr><td class="catent">Seeligmann, T., Torrilhon, G.&nbsp;L., and Falconnet, H. India Rubber and
+Gutta Percha. Trans. by J.&nbsp;G. McIntosh</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Seidell, A. Solubilities of Inorganic and Organic Substances</td><td class="catvolume">8vo,</td><td class="catprice">4 50</td></tr>
+
+<tr><td class="catent">Seligman, B. Aluminum. (Metallurgy Series.)</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Sellew, W.&nbsp;H. Steel Rails</td><td class="catvolume">4to,</td><td class="catprice">*10 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Railway Maintenance Engineering</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Senter, G. Outlines of Physical Chemistry</td><td class="catvolume">12mo,</td><td class="catprice">*1 75</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Text-book of Inorganic Chemistry</td><td class="catvolume">12mo,</td><td class="catprice">*1 75</td></tr>
+
+<tr><td class="catent">Sever, G.&nbsp;F. Electric Engineering Experiments</td><td class="catvolume">8vo, boards,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Sever, G.&nbsp;F., and Townsend, F. Laboratory and Factory Tests in Electrical
+Engineering</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Sewall, C.&nbsp;H. Wireless Telegraphy</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Lessons in Telegraphy</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Sewell, T. The Construction of Dynamos</td><td class="catvolume">8vo,</td><td class="catprice">*3 00<span class='pagenum'><a name="Page_26a" id="Page_26a">[26]</a></span></td></tr>
+
+<tr><td class="catent">Sexton, A.&nbsp;H. Fuel and Refractory Materials</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Chemistry of the Materials of Engineering</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Alloys (Non-Ferrous)</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Sexton, A.&nbsp;H., and Primrose, J.&nbsp;S.&nbsp;G. The Metallurgy of Iron and Steel.</td><td class="catvolume">8vo,</td><td class="catprice">*6 50</td></tr>
+
+<tr><td class="catent">Seymour, A. Modern Printing Inks</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Shaw, Henry S.&nbsp;H. Mechanical Integrators. (Science Series No. 83.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Shaw, S. History of the Staffordshire Potteries</td><td class="catvolume">8vo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Chemistry of Compounds Used in Porcelain Manufacture</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Shaw, T.&nbsp;R. Driving of Machine Tools</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Shaw, W.&nbsp;N. Forecasting Weather</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Sheldon, S., and Hausmann, E. Direct Current Machines</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Alternating Current Machines</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Sheldon, S., and Hausmann, E. Electric Traction and Transmission Engineering</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Physical Laboratory Experiments, for Engineering Students</td><td class="catvolume">8vo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Shields, J.&nbsp;E. Notes on Engineering Construction</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Shreve, S.&nbsp;H. Strength of Bridges and Roofs</td><td class="catvolume">8vo,</td><td class="catprice">3 50</td></tr>
+
+<tr><td class="catent">Shunk, W.&nbsp;F. The Field Engineer</td><td class="catvolume">12mo, morocco,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">Simmons, W.&nbsp;H., and Appleton, H.&nbsp;A. Handbook of Soap Manufacture,</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Simmons, W.&nbsp;H., and Mitchell, C.&nbsp;A. Edible Fats and Oils</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Simpson, G. The Naval Constructor</td><td class="catvolume">12mo, morocco,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Simpson, W. Foundations</td><td class="catvolume">8vo. (<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Sinclair, A. Development of the Locomotive Engine</td><td class="catvolume">8vo, half leather,</td><td class="catprice">5 00</td></tr>
+
+<tr><td class="catent">Sindall, R.&nbsp;W. Manufacture of Paper. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Sindall, R.&nbsp;W., and Bacon, W.&nbsp;N. The Testing of Wood Pulp</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Sloane, T. O'C. Elementary Electrical Calculations</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Smallwood, J.&nbsp;C. Mechanical Laboratory Methods. (Van Nostrand's Textbooks)</td><td class="catvolume">12mo, leather,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Smith, C.&nbsp;A.&nbsp;M. Handbook of Testing, MATERIALS</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Smith, C.&nbsp;A.&nbsp;M., and Warren, A.&nbsp;G. New Steam Tables</td><td class="catvolume">8vo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Smith, C.&nbsp;F. Practical Alternating Currents and Testing</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Practical Testing of Dynamos and Motors</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Smith, F.&nbsp;A. Railway Curves</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Standard Turnouts on American Railroads</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Maintenance of Way Standards</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Smith, F.&nbsp;E. Handbook of General Instruction for Mechanics</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Smith, H.&nbsp;G. Minerals and the Microscope</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Smith, J.&nbsp;C. Manufacture of Paint</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Smith, R.&nbsp;H. Principles of Machine Work</td><td class="catvolume">12mo,</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Advanced Machine Work</td><td class="catvolume">12mo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Smith, W. Chemistry of Hat Manufacturing</td><td class="catvolume">12mo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Snell, A.&nbsp;T. Electric Motive Power</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Snow, W.&nbsp;G. Pocketbook of Steam Heating and Ventilation.</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Snow, W.&nbsp;G., and Nolan, T. Ventilation of Buildings. (Science Series No. 5.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Soddy, F. Radioactivity</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Solomon, M. Electric Lamps. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00<span class='pagenum'><a name="Page_27a" id="Page_27a">[27]</a></span></td></tr>
+
+<tr><td class="catent">Somerscales, A.&nbsp;N. Mechanics for Marine Engineers</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Mechanical and Marine Engineering Science</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Sothern, J.&nbsp;W. The Marine Steam Turbine</td><td class="catvolume">8vo,</td><td class="catprice">*6 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Verbal Notes and Sketches for Marine Engineers</td><td class="catvolume">8vo,</td><td class="catprice">*7 50</td></tr>
+
+<tr><td class="catent">Sothern, J.&nbsp;W., and Sothern, R.&nbsp;M. Elementary
+  Mathematics for Marine Engineers</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Simple Problems in Marine Engineering Design</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Southcombe, J.&nbsp;E. Chemistry of the Oil Industries.
+  (Outlines of Industrial Chemistry.)</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Soxhlet, D.&nbsp;H. Dyeing and Staining Marble. Trans.
+  by A. Morris and H. Robson</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Spangenburg, L. Fatigue of Metals. Translated by
+  S.&nbsp;H. Shreve. (Science Series No. 23.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Specht, G.&nbsp;J., Hardy, A.&nbsp;S., McMaster, J.&nbsp;B., and
+  Walling. Topographical Surveying. (Science Series
+  No. 72.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Spencer, A.&nbsp;S. Design of Steel-Framed Sheds</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Speyers, C.&nbsp;L. Text-book of Physical Chemistry</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Spiegel, L. Chemical Constitution and Physiological
+  Action. (Trans. by C. Luedeking and A.&nbsp;C. Boylston.)</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Sprague, E.&nbsp;H. Hydraulics</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Elements of Graphic Statics</td><td class="catvolume">8vo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Stability of Masonry</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Elementary Mathematics for Engineers</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Stahl, A.&nbsp;W. Transmission of Power. (Science Series
+  No. 28.)</td><td class="catvolume">16mo,</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Stahl, A.&nbsp;W., and Woods, A.&nbsp;T. Elementary Mechanism</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Staley, C., and Pierson, G.&nbsp;S. The Separate System of
+  Sewerage</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Standage, H.&nbsp;C. Leatherworkers' Manual</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Sealing Waxes, Wafers, and Other Adhesives</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Agglutinants of all Kinds for all Purposes</td><td class="catvolume">12mo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Stanley, H. Practical Applied Physics</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Stansbie, J.&nbsp;H. Iron and Steel. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Steadman, F.&nbsp;M. Unit Photography</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Stecher, G.&nbsp;E. Cork. Its Origin and Industrial Uses</td><td class="catvolume">12mo,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">Steinman, D.&nbsp;B. Suspension Bridges and Cantilevers.
+  (Science Series No. 127.)</td><td class="catvolume">&nbsp;</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Melan's Steel Arches and Suspension Bridges</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Stevens, H.&nbsp;P. Paper Mill Chemist</td><td class="catvolume">16mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Stevens, J.&nbsp;S. Theory of Measurements</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Stevenson, J.&nbsp;L. Blast-Furnace Calculations</td><td class="catvolume">12mo, leather,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Stewart, G. Modern Steam Traps</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Stiles, A. Tables for Field Engineers</td><td class="catvolume">12mo,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">Stodola, A. Steam Turbines. Trans. by L.&nbsp;C.
+  Loewenstein</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Stone, H. The Timbers of Commerce</td><td class="catvolume">8vo,</td><td class="catprice">3 50</td></tr>
+
+<tr><td class="catent">Stopes, M. Ancient Plants</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; The Study of Plant Life</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Sudborough, J.&nbsp;J., and James, T.&nbsp;C. Practical Organic
+  Chemistry</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Suffling, E.&nbsp;R. Treatise on the Art of Glass Painting</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Sullivan, T.&nbsp;V., and Underwood, N. Testing and
+  Valuation of Building and Engineering Materials</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Sur, F.&nbsp;J.&nbsp;S. Oil Prospecting and Extracting</td><td class="catvolume">8vo,</td><td class="catprice">*1 00<span class='pagenum'><a name="Page_28a" id="Page_28a">[28]</a></span></td></tr>
+
+<tr><td class="catent">Svenson, C.&nbsp;L. Handbook on Piping</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Swan, K. Patents, Designs and Trade Marks.
+  (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Swinburne, J., Wordingham, C.&nbsp;H., and Martin, T.&nbsp;C.
+  Electric Currents. (Science Series No. 109.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Swoope, C.&nbsp;W. Lessons in Practical Electricity</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Tailfer, L. Bleaching Linen and Cotton Yarn and Fabrics</td><td class="catvolume">8vo,</td><td class="catprice">6 00</td></tr>
+
+<tr><td class="catent">Tate, J.&nbsp;S. Surcharged and Different Forms of
+  Retaining-walls. (Science Series No. 7.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Taylor, F.&nbsp;N. Small Water Supplies</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Masonry in Civil Engineering</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Taylor, T.&nbsp;U. Surveyor's Handbook</td><td class="catvolume">12mo, leather,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Backbone of Perspective</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Taylor, W.&nbsp;P. Practical Cement Testing</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Templeton, W. Practical Mechanic's Workshop Companion</td><td class="catvolume">12mo, morocco,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Tenney, E.&nbsp;H. Test Methods for Steam Power Plants.
+  (Van Nostrand's Textbooks.)</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Terry, H.&nbsp;L. India Rubber and its Manufacture.
+  (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Thayer, H.&nbsp;R. Structural Design.</td><td class="catvolume">8vo.</td><td class="catprice">&nbsp;</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. I. Elements of Structural Design</td><td class="catvolume">&nbsp;</td><td class="catprice">*2 00</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. II. Design of Simple Structures</td><td class="catvolume">&nbsp;</td><td class="catprice">*4 00</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. III. Design of Advanced Structures</td><td class="catvolume">(<i>In Preparation.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Foundations and Masonry</td><td class="catvolume">(<i>In Preparation.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Thiess, J.&nbsp;B., and Joy, G.&nbsp;A. Toll Telephone Practice</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Thom, C., and Jones, W.&nbsp;H. Telegraphic Connections</td><td class="catvolume">oblong, 12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Thomas, C.&nbsp;W. Paper-makers' Handbook</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Thompson, A.&nbsp;B. Oil Fields of Russia</td><td class="catvolume">4to,</td><td class="catprice">*7 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Oil Field Development</td><td class="catvolume">&nbsp;</td><td class="catprice">7 50</td></tr>
+
+<tr><td class="catent">Thompson, S.&nbsp;P. Dynamo Electric Machines. (Science
+  Series No. 75.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Thompson, W.&nbsp;P. Handbook of Patent Law of All Countries</td><td class="catvolume">16mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Thomson, G. Modern Sanitary Engineering</td><td class="catvolume">12mo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Thomson, G.&nbsp;S. Milk and Cream Testing</td><td class="catvolume">12mo,</td><td class="catprice">*1 75</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Modern Sanitary Engineering, House Drainage, etc.</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Thornley, T. Cotton Combing Machines</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Cotton Waste</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Cotton Spinning.</td><td class="catvolume">8vo.</td><td class="catprice">&nbsp;</td></tr>
+<tr><td class="catent" style="padding-left: 4em">First Year</td><td class="catvolume">&nbsp;</td><td class="catprice">*1 50</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Second Year</td><td class="catvolume">&nbsp;</td><td class="catprice">*3 00</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Third Year</td><td class="catvolume">&nbsp;</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Thurso, J.&nbsp;W. Modern Turbine Practice</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Tidy, C. Meymott. Treatment of Sewage. (Science Series
+  No. 94.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Tillmans, J. Water Purification and Sewage Disposal.
+  Trans. by Hugh S. Taylor</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Tinney, W.&nbsp;H. Gold-mining Machinery</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Titherley, A.&nbsp;W. Laboratory Course of Organic Chemistry</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Tizard, H.&nbsp;T. Indicators</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;<span class='pagenum'><a name="Page_29a" id="Page_29a">[29]</a></span></td></tr>
+
+<tr><td class="catent">Toch, M. Chemistry and Technology of Paints</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Materials for Permanent Painting</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Tod, J., and McGibbon, W.&nbsp;C. Marine Engineers' Board
+  of Trade Examinations</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Todd, J., and Whall, W.&nbsp;B. Practical Seamanship</td><td class="catvolume">8vo,</td><td class="catprice">8 00</td></tr>
+
+<tr><td class="catent">Tonge, J. Coal. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Townsend, F. Alternating Current Engineering</td><td class="catvolume">8vo, boards,</td><td class="catprice">*0 75</td></tr>
+
+<tr><td class="catent">Townsend, J.&nbsp;S. Ionization of Gases by Collision</td><td class="catvolume">8vo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Transactions of the American Institute of Chemical
+  Engineers, 8vo. Eight volumes now ready. Vol. I.
+  to IX., 1908-1916</td><td class="catvolume">8vo, each,</td><td class="catprice">6 00</td></tr>
+
+<tr><td class="catent">Traverse Tables. (Science Series No. 115.)</td><td class="catvolume">16mo,  0 50</td></tr>
+<tr><td class="catent">&nbsp;</td><td class="catvolume">morocco,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">Treiber, E. Foundry Machinery. Trans. by C. Salter</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Trinks, W., and Housum, C. Shaft Governors. (Science
+  Series No. 122.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Trowbridge, W.&nbsp;P. Turbine Wheels. (Science Series No.
+  44.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Tucker, J.&nbsp;H. A Manual of Sugar Analysis</td><td class="catvolume">8vo,</td><td class="catprice">3 50</td></tr>
+
+<tr><td class="catent">Tunner, P.&nbsp;A. Treatise on Roll-turning. Trans. by
+  J.&nbsp;B. Pearse.</td><td class="catvolume">8vo, text and folio atlas,</td><td class="catprice">10 00</td></tr>
+
+<tr><td class="catent">Turnbull, Jr., J., and Robinson, S.&nbsp;W. A Treatise on
+  the Compound Steam-engine. (Science Series No. 8.)</td><td class="catvolume">16mo,</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Turner, H. Worsted Spinners' Handbook</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Turrill, S.&nbsp;M. Elementary Course in Perspective</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Twyford, H.&nbsp;B. Purchasing</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Tyrrell, H.&nbsp;G. Design and Construction of Mill
+  Buildings</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Concrete Bridges and Culverts</td><td class="catvolume">16mo, leather,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Artistic Bridge Design</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Underhill, C.&nbsp;R. Solenoids, Electromagnets and
+  Electromagnetic Windings</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Underwood, N., and Sullivan, T.&nbsp;V. Chemistry and
+  Technology of Printing Inks</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Urquhart, J.&nbsp;W. Electro-plating</td><td class="catvolume">12mo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Electrotyping</td><td class="catvolume">12mo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Usborne, P.&nbsp;O.&nbsp;G. Design of Simple Steel Bridges</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Vacher, F. Food Inspector's Handbook</td><td class="catvolume">12mo,</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Van Nostrand's Chemical Annual. Third issue 1913</td><td class="catvolume">leather, 12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Year Book of Mechanical Engineering Data</td><td class="catvolume">(<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Van Wagenen, T.&nbsp;F. Manual of Hydraulic Mining</td><td class="catvolume">16mo,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">Vega, Baron Von. Logarithmic Tables</td><td class="catvolume">8vo, cloth,</td><td class="catprice">2 00</td></tr>
+<tr><td class="catent">&nbsp;</td><td class="catvolume">half morocco,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">Vincent, C. Ammonia and its Compounds. Trans. by
+  M.&nbsp;J. Salter</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Volk, C. Haulage and Winding Appliances</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Von Georgievics, G. Chemical Technology of Textile
+  Fibres. Trans. by C. Salter</td><td class="catvolume">8vo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Chemistry of Dyestuffs. Trans. by C. Salter</td><td class="catvolume">8vo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">Vose, G.&nbsp;L. Graphic Method for Solving Certain
+  Questions in Arithmetic and Algebra (Science
+  Series No. 16.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Vosmaer, A. Ozone</td><td class="catvolume">8vo,</td><td class="catprice">*2 50<span class='pagenum'><a name="Page_30a" id="Page_30a">[30]</a></span></td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Wabner, R. Ventilation in Mines. Trans. by C. Salter</td><td class="catvolume">8vo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">Wade, E.&nbsp;J. Secondary Batteries</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">Wadmore, T.&nbsp;M. Elementary Chemical Theory</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Wadsworth, C. Primary Battery Ignition</td><td class="catvolume">12mo,</td><td class="catprice">*0 50</td></tr>
+
+<tr><td class="catent">Wagner, E. Preserving Fruits, Vegetables, and Meat</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Wagner, J.&nbsp;B. A Treatise on the Natural and Artificial
+  Processes of Wood Seasoning</td><td class="catvolume">8vo, (<i>In Press.</i>)</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Waldram, P.&nbsp;J. Principles of Structural Mechanics</td><td class="catvolume">12mo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Walker, F. Aerial Navigation</td><td class="catvolume">8vo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Dynamo Building. (Science Series No. 98.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Walker, J. Organic Chemistry for Students of Medicine</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Walker, S.&nbsp;F. Steam Boilers, Engines and Turbines</td><td class="catvolume">8vo,</td><td class="catprice">3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Refrigeration, Heating and Ventilation on
+  Shipboard</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Electricity in Mining</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Wallis-Tayler, A.&nbsp;J. Bearings and Lubrication</td><td class="catvolume">8vo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Aerial or Wire Ropeways</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Sugar Machinery</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Walsh, J.&nbsp;J. Chemistry and Physics of Mining and
+  Mine Ventilation,</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Wanklyn, J.&nbsp;A. Water Analysis</td><td class="catvolume">12mo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">Wansbrough, W.&nbsp;D. The A B C of the Differential
+  Calculus</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Slide Valves</td><td class="catvolume">12mo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Waring, Jr., G.&nbsp;E. Sanitary Conditions. (Science
+  Series No. 31.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Sewerage and Land Drainage</td><td class="catvolume">&nbsp;</td><td class="catprice">*6 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Modern Methods of Sewage Disposal</td><td class="catvolume">12mo,</td><td class="catprice">2 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; How to Drain a House</td><td class="catvolume">12mo,</td><td class="catprice">1 25</td></tr>
+
+<tr><td class="catent">Warnes, A.&nbsp;R. Coal Tar Distillation</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Warren, F.&nbsp;D. Handbook on Reinforced Concrete</td><td class="catvolume">12mo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Watkins, A. Photography. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Watson, E.&nbsp;P. Small Engines and Boilers</td><td class="catvolume">12mo,</td><td class="catprice">1 25</td></tr>
+
+<tr><td class="catent">Watt, A. Electro-plating and Electro-refining of Metals</td><td class="catvolume">8vo,</td><td class="catprice">*4 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Electro-metallurgy</td><td class="catvolume">12mo,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; The Art of Soap Making</td><td class="catvolume">8vo,</td><td class="catprice">3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Leather Manufacture</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Paper-Making</td><td class="catvolume">8vo,</td><td class="catprice">3 00</td></tr>
+
+<tr><td class="catent">Webb, H.&nbsp;L. Guide to the Testing of Insulated Wires
+  and Cables</td><td class="catvolume">12mo,</td><td class="catprice">1 00</td></tr>
+
+<tr><td class="catent">Webber, W.&nbsp;H.&nbsp;Y. Town Gas. (Westminster Series.)</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Weisbach, J. A Manual of Theoretical Mechanics</td><td class="catvolume">8vo,</td><td class="catprice">*6 00</td></tr>
+<tr><td class="catent">&nbsp;</td><td class="catvolume">sheep,</td><td class="catprice">*7 50</td></tr>
+
+<tr><td class="catent">Weisbach, J., and Herrmann, G. Mechanics of Air
+  Machinery</td><td class="catvolume">8vo,</td><td class="catprice">*3 75</td></tr>
+
+<tr><td class="catent">Wells, M.&nbsp;B. Steel Bridge Designing</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Weston, E.&nbsp;B. Loss of Head Due to Friction of Water
+  in Pipes</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Wheatley, O. Ornamental Cement Work</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Whipple, S. An Elementary and Practical Treatise on
+  Bridge Building</td><td class="catvolume">8vo,</td><td class="catprice">3 00</td></tr>
+
+<tr><td class="catent">White, C.&nbsp;H. Methods of Metallurgical Analysis. (Van
+  Nostrand's Textbooks.)</td><td class="catvolume">12mo,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">White, G.&nbsp;F. Qualitative Chemical Analysis</td><td class="catvolume">12mo,</td><td class="catprice">*1 25<span class='pagenum'><a name="Page_31a" id="Page_31a">[31]</a></span></td></tr>
+
+<tr><td class="catent">White, G.&nbsp;T. Toothed Gearing</td><td class="catvolume">12mo,</td><td class="catprice">*1 25</td></tr>
+
+<tr><td class="catent">Wilcox, R.&nbsp;M. Cantilever Bridges. (Science Series No. 25.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Wilda, H. Steam Turbines. Trans. by C. Salter</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Cranes and Hoists. Trans. by C. Salter</td><td class="catvolume">12mo,</td><td class="catprice">1 50</td></tr>
+
+<tr><td class="catent">Wilkinson, H.&nbsp;D. Submarine Cable Laying and Repairing</td><td class="catvolume">8vo,</td><td class="catprice">*6 00</td></tr>
+
+<tr><td class="catent">Williamson, J. Surveying</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Williamson, R.&nbsp;S. On the Use of the Barometer</td><td class="catvolume">4to,</td><td class="catprice">15 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Practical Tables in Meteorology and Hypsometry</td><td class="catvolume">4to,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">Wilson, F.&nbsp;J., and Heilbron, I.&nbsp;M. Chemical Theory and Calculations</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Wilson, J.&nbsp;F. Essentials of Electrical Engineering</td><td class="catvolume">8vo,</td><td class="catprice">2 50</td></tr>
+
+<tr><td class="catent">Wimperis, H.&nbsp;E. Internal Combustion Engine</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Application of Power to Road Transport</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Primer of Internal Combustion Engine</td><td class="catvolume">12mo,</td><td class="catprice">*1 00</td></tr>
+
+<tr><td class="catent">Winchell, N.&nbsp;H., and A.&nbsp;N. Elements of Optical Mineralogy</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">Winslow, A. Stadia Surveying. (Science Series No. 77.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Wisser, Lieut. J.&nbsp;P. Explosive Materials. (Science Series No. 70.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Wisser, Lieut. J.&nbsp;P. Modern Gun Cotton. (Science Series No. 89.)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Wolff, C.&nbsp;E. Modern Locomotive Practice</td><td class="catvolume">8vo,</td><td class="catprice">*4 20</td></tr>
+
+<tr><td class="catent">Wood, De V. Luminiferous Aether. (Science Series No. 85)</td><td class="catvolume">16mo,</td><td class="catprice">0 50</td></tr>
+
+<tr><td class="catent">Wood, J.&nbsp;K. Chemistry of Dyeing. (Chemical Monographs No. 2.)</td><td class="catvolume">12mo,</td><td class="catprice">*0 75</td></tr>
+
+<tr><td class="catent">Worden, E.&nbsp;C. The Nitrocellulose Industry. Two Volumes</td><td class="catvolume">8vo,</td><td class="catprice">*10 00</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Technology of Cellulose Esters. In 10 volumes.</td><td class="catvolume">8vo.</td><td class="catprice">&nbsp;</td></tr>
+<tr><td class="catent" style="padding-left: 4em">Vol. VIII. Cellulose Acetate</td><td class="catvolume">&nbsp;</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Wren, H. Organometallic Compounds of Zinc and Magnesium. (Chemical
+Monographs No. 1.)</td><td class="catvolume">12mo,</td><td class="catprice">*0 75</td></tr>
+
+<tr><td class="catent">Wright, A.&nbsp;C. Analysis of Oils and Allied Substances</td><td class="catvolume">8vo,</td><td class="catprice">*3 50</td></tr>
+
+<tr><td class="catent">&mdash;&mdash; Simple Method for Testing Painters' Materials</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Wright, F.&nbsp;W. Design of a Condensing Plant</td><td class="catvolume">12mo,</td><td class="catprice">*1 50</td></tr>
+
+<tr><td class="catent">Wright, H.&nbsp;E. Handy Book for Brewers</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Wright, J. Testing, Fault Finding, etc., for Wiremen. (Installation
+Manuals Series.)</td><td class="catvolume">16mo,</td><td class="catprice">*0 50</td></tr>
+
+<tr><td class="catent">Wright, T.&nbsp;W. Elements of Mechanics</td><td class="catvolume">8vo,</td><td class="catprice">*2 50</td></tr>
+
+<tr><td class="catent">Wright, T.&nbsp;W., and Hayford, J.&nbsp;F. Adjustment of Observations</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Wynne, W.&nbsp;E., and Sparagen, W. Handbook of Engineering Mathematics</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Yoder, J.&nbsp;H., and Wharen, G.&nbsp;B. Locomotive Valves and Valve Gears</td><td class="catvolume">8vo,</td><td class="catprice">*3 00</td></tr>
+
+<tr><td class="catent">Young, J.&nbsp;E. Electrical Testing for Telegraph Engineers</td><td class="catvolume">8vo,</td><td class="catprice">*4 00</td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td class="catent">Zahner, R. Transmission of Power. (Science Series No. 40.)</td><td class="catvolume">16mo,</td><td class="catprice">&nbsp;</td></tr>
+
+<tr><td class="catent">Zeidler, J., and Lustgarten, J. Electric Arc Lamps</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+
+<tr><td class="catent">Zeuner, A. Technical Thermodynamics. Trans. by J.&nbsp;F. Klein. Two Volumes</td><td class="catvolume">8vo,</td><td class="catprice">*8 00</td></tr>
+
+<tr><td class="catent">Zimmer, G.&nbsp;F. Mechanical Handling and Storing of Materials</td><td class="catvolume">4to,</td><td class="catprice">*12 50</td></tr>
+
+<tr><td class="catent">Zipser, J. Textile Raw Materials. Trans. by C. Salter</td><td class="catvolume">8vo,</td><td class="catprice">*5 00</td></tr>
+
+<tr><td class="catent">Zur Nedden, F. Engineering Workshop Machines and Processes. Trans.
+by J.&nbsp;A. Davenport</td><td class="catvolume">8vo,</td><td class="catprice">*2 00</td></tr>
+</table>
+
+<div class="bbox">
+<p class="center bb" style="font-size: 130%; font-weight: bold"><span class='pagenum'><a name="Page_32a" id="Page_32a">[32]</a></span>
+<span class="smcap">D. Van Nostrand Company</span></p>
+
+
+
+<p class="center">are prepared to supply, either from<br />
+their complete stock or at<br />
+short notice,<br /><br />
+
+<span style="font-size: 140%; padding-right: 4em">Any Technical or</span><br />
+<span style="font-size: 140%; padding-left: 4em">Scientific Book</span></p>
+
+<p style="padding-top: 1em; text-align: justify; margin-left: auto; margin-right: auto; width: 20em; text-indent: 0em">
+In addition to publishing a very large
+and varied number of <span class="smcap">Scientific and
+Engineering Books</span>, D. Van Nostrand
+Company have on hand the largest
+assortment in the United States of such
+books issued by American and foreign
+publishers.</p>
+
+
+<p style="padding-top: 1em; text-align: justify; margin-left: auto; margin-right: auto; width: 20em; text-indent: 0em">All inquiries are cheerfully and carefully
+answered and complete catalogs
+sent free on request.</p>
+
+<p class="bt"><span class="smcap" style="padding-left: 1em">25 Park Place</span><span class="smcap" style="padding-left: 13em">New York</span></p>
+</div>
+
+</div>
+
+<div class="note">
+
+<h4>Transcriber's Note</h4>
+<p>Obvious typographical errors have been corrected. See the detailed list below.
+If your cursor turns into a hand when it is hovered over an illustration, the click
+on it will take you to the larger image.</p>
+
+<ul>
+<li>page <a href="#Page_18">018</a>&mdash;typo fixed: changed 'Oregan' to 'Oregon'</li>
+<li>page <a href="#Page_27">027</a>&mdash;typo fixed: changed 'Michigian' to 'Michigan'</li>
+<li>page <a href="#Page_46">046</a>&mdash;typo fixed: changed 'resistence' to 'resistance'</li>
+<li>page <a href="#Page_58">058</a>&mdash;typo fixed: changed 'homus' to 'humus'</li>
+<li>page <a href="#Page_69">069</a>&mdash;typo fixed: changed 'resistence' to 'resistance'</li>
+<li>page <a href="#Page_74">074</a>&mdash;typo fixed: changed 'ilicijolia' to 'ilicifolia'</li>
+<li>page <a href="#Page_84">084</a>&mdash;typo fixed: changed 'Novia Scota' to 'Nova Scotia'</li>
+<li>page <a href="#Page_86">086</a>&mdash;typo fixed: changed 'visable' to 'visible'</li>
+<li>page <a href="#Page_103">103</a>&mdash;typo fixed: changed 'energed' to 'emerged'</li>
+<li>page <a href="#Page_106">106</a>&mdash;typo fixed: changed 'absolutley' to 'absolutely'</li>
+<li>page <a href="#Page_110">110</a>&mdash;typo fixed: changed 'has' to 'had'</li>
+<li>page <a href="#Page_131">131</a>&mdash;typo fixed: changed 'accomodate' to 'accommodate'</li>
+<li>page <a href="#Page_163">163</a>&mdash;typo fixed: changed 'hydrodeik' to 'hygrodeik'</li>
+<li>page <a href="#Page_181">181</a>&mdash;typo fixed: changed 'longitutudinal' to 'longitudinal'</li>
+<li>page <a href="#Page_198">198</a>&mdash;typo fixed: changed 'accomodate' to 'accommodate'</li>
+<li>page <a href="#Page_202">202</a>&mdash;typo fixed: changed 'ecomony' to 'economy'</li>
+<li>page <a href="#Page_204">204</a>&mdash;typo fixed: changed 'minumim' to 'minimum'</li>
+<li>page <a href="#Page_239">239</a>&mdash;typo fixed: changed 'horizonal' to 'horizontal'</li>
+<li>page <a href="#Page_257">257</a>&mdash;typo fixed: changed 'arrangment' to 'arrangement'</li>
+<li>page <a href="#Page_266">266</a>&mdash;typo fixed: changed 'applicances' to 'appliances'</li>
+<li>page <a href="#Page_267">267</a>&mdash;typo fixed: changed 'specialities' to 'specialties'</li>
+<li>page <a href="#Page_267">267</a>&mdash;typo fixed: changed 'theary' to 'theory'</li>
+<li>page <a href="#Page_274">274</a>&mdash;typo fixed: changed 'Annual of' to 'Annual or'</li>
+</ul>
+
+</div>
+
+
+
+
+
+
+
+
+<pre>
+
+
+
+
+
+End of the Project Gutenberg EBook of Seasoning of Wood, by Joseph B. Wagner
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+</body>
+</html>
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+The Project Gutenberg EBook of Seasoning of Wood, by Joseph B. Wagner
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Seasoning of Wood
+
+Author: Joseph B. Wagner
+
+Release Date: September 12, 2008 [EBook #26598]
+
+Language: English
+
+Character set encoding: ASCII
+
+*** START OF THIS PROJECT GUTENBERG EBOOK SEASONING OF WOOD ***
+
+
+
+
+Produced by Jason Isbell, Irma Spehar and the Online
+Distributed Proofreading Team at https://www.pgdp.net
+
+
+
+
+
+                           SEASONING OF WOOD
+
+               A TREATISE ON THE NATURAL AND ARTIFICIAL
+                 PROCESSES EMPLOYED IN THE PREPARATION
+                      OF LUMBER FOR MANUFACTURE,
+                   WITH DETAILED EXPLANATIONS OF ITS
+                 USES, CHARACTERISTICS AND PROPERTIES
+
+
+                            _ILLUSTRATIONS_
+                                  BY
+                           JOSEPH B. WAGNER
+                         AUTHOR OF "COOPERAGE"
+
+
+                            [Illustration]
+
+
+                               NEW YORK
+                        D. VAN NOSTRAND COMPANY
+                             25 PARK PLACE
+                                 1917
+
+
+                          COPYRIGHT, 1917, BY
+                        D. VAN NOSTRAND COMPANY
+
+
+                          THE.PLIMPTON.PRESS
+                          NORWOOD.MASS.U.S.A
+
+
+
+
+                                PREFACE
+
+
+The seasoning and kiln-drying of wood is such an important process in
+the manufacture of woods that a need for fuller information regarding
+it, based upon scientific study of the behavior of various species at
+different mechanical temperatures, and under different drying
+processes is keenly felt. Everyone connected with the woodworking
+industry, or its use in manufactured products, is well aware of the
+difficulties encountered in properly seasoning or removing the
+moisture content without injury to the timber, and of its
+susceptibility to atmospheric conditions after it has been thoroughly
+seasoned. There is perhaps no material or substance that gives up its
+moisture with more resistance than wood does. It vigorously defies the
+efforts of human ingenuity to take away from it, without injury or
+destruction, that with which nature has so generously supplied it.
+
+In the past but little has been known of this matter further than the
+fact that wood contained moisture which had to be removed before the
+wood could be made use of for commercial purposes. Within recent
+years, however, considerable interest has been awakened among
+wood-users in the operation of kiln-drying. The losses occasioned in
+air-drying and improper kiln-drying, and the necessity for getting the
+material dry as quickly as possible after it has come from the saw, in
+order to prepare it for manufacturing purposes, are bringing about a
+realization of the importance of a technical knowledge of the subject.
+
+Since this particular subject has never before been represented by any
+technical work, and appears to have been neglected, it is hoped that
+the trade will appreciate the endeavor in bringing this book before
+them, as well as the difficulties encountered in compiling it, as it
+is the first of its kind in existence. The author trusts that his
+efforts will present some information that may be applied with
+advantage, or serve at least as a matter of consideration or
+investigation.
+
+In every case the aim has been to give the facts, and wherever a
+machine or appliance has been illustrated or commented upon, or the
+name of the maker has been mentioned, it has not been with the
+intention either of recommending or disparaging his or their work, but
+has been made use of merely to illustrate the text.
+
+The preparation of the following pages has been a work of pleasure to
+the author. If they prove beneficial and of service to his
+fellow-workmen he will have been amply repaid.
+
+                                                      THE AUTHOR.
+
+    September, 1917
+
+
+
+
+                               CONTENTS
+
+
+                               SECTION I
+
+                                TIMBER
+                                                                   PAGES
+
+Characteristics and Properties of Same--Structure
+of Wood--Properties of Wood--Classes of Trees                        1-7
+
+                              SECTION II
+
+                           CONIFEROUS TREES
+
+Wood of Coniferous Trees--Bark and Pith--Sapwood and Heartwood--The
+Annual or Yearly Ring--Spring- and Summer-Wood--Anatomical
+Structure--List of Important Coniferous Trees                       8-30
+
+                              SECTION III
+
+                          BROAD-LEAVED TREES
+
+Wood of Broad-leaved Trees--Minute Structure--List of Most
+Important Broad-leaved Trees--Red Gum--Range of Red Gum--Form
+of Red Gum--Tolerance of Red Gum--Its Demands upon Soil and
+Moisture--Reproduction of Red Gum--Second-growth Red Gum--Tupelo
+Gum--Uses of Tupelo Gum--Range of Tupelo Gum                       31-85
+
+                              SECTION IV
+
+            GRAIN, COLOR, ODOR, WEIGHT, AND FIGURE IN WOOD
+
+Different Grains of Wood--Color and Odor of Wood--Weight of
+Wood--Weight of Kiln-dried Wood of Different Species--Figure in
+Wood                                                               86-97
+
+                               SECTION V
+
+                            ENEMIES OF WOOD
+
+General Remarks--Ambrosia or Timber Beetles--Round-headed
+Borers--Flat-headed Borers--Timber Worms--Powder Post
+Borers--Conditions Favorable for Insect Injury--Crude
+Products--Round Timber with Bark on--How to Prevent
+Injury--Saplings--Stave, Heading, and Shingle Bolts--Unseasoned
+Products in the Rough--Seasoned Products in the Rough--Dry
+Cooperage Stock and Wooden Truss Hoops--Staves and Heads
+of Barrels Containing Alcoholic Liquids                           98-113
+
+                              SECTION VI
+
+                             WATER IN WOOD
+
+Distribution of Water in Wood--Seasonal Distribution of Water in
+Wood--Composition of Sap--Effects of Moisture on Wood--The
+Fibre-Saturation Point in Wood                                   114-118
+
+                              SECTION VII
+
+                           WHAT SEASONING IS
+
+What Seasoning Is--Difference Between Seasoned and Unseasoned
+Wood--Manner of Evaporation of Water--Absorption of Water
+by Dry Wood--Rapidity of Evaporation--Physical Properties
+that Influence Drying                                            119-127
+
+                             SECTION VIII
+
+                        ADVANTAGES OF SEASONING
+
+Advantages of Seasoning--Prevention of Checking and
+Splitting--Shrinkage of Wood--Expansion of Wood--Elimination of
+Stain and Mildew                                                 128-137
+
+                              SECTION IX
+
+                      DIFFICULTIES OF DRYING WOOD
+
+Difficulties of Drying Wood--Changes Rendering Drying
+Difficult--Losses Due to Improper Kiln-drying--Properties of
+Wood that Effect Drying--Unsolved Problems in Kiln-drying        138-144
+
+                               SECTION X
+
+                         HOW WOOD IS SEASONED
+
+Methods of Drying--Drying at Atmospheric Pressure--Drying Under
+Pressure and Vacuum--Impregnation Methods--Preliminary
+Treatments--Out-of-door Seasoning                                145-155
+
+                              SECTION XI
+
+                          KILN-DRYING OF WOOD
+
+Advantages of Kiln-drying over Air Drying--Physical Conditions
+Governing the Drying of Wood--Theory of Kiln-drying--Requirements
+in a Satisfactory Dry Kiln--Kiln-drying--Remarks--Underlying
+Principles--Objects of Kiln-drying--Conditions of Success--Different
+Treatments According to Kind--Temperature Depends--Air
+Circulation--Humidity--Kiln-drying--Pounds of Water Lost in Drying
+100 Pounds of Green Wood in the Kiln--Kiln-drying Gum--Preliminary
+Steaming--Final Steaming--Kiln-drying of Green Red Gum           156-184
+
+                              SECTION XII
+
+                          TYPES OF DRY KILNS
+
+Different types of Dry Kilns--The "Blower" or "Hot Blast" Dry
+Kiln--Operating the "Blower" or "Hot Blast" Dry Kiln--The
+"Pipe" or "Moist-Air" Dry Kiln--Operating the "Pipe" or
+"Moist-Air" Dry Kiln--Choice of Drying Method--Kilns of
+Different Types--The "Progressive" Dry Kiln--The "Apartment"
+Dry Kiln--The "Pocket" Dry Kiln--The "Tower" Dry Kiln--The
+"Box" Dry Kiln                                                   185-205
+
+                             SECTION XIII
+
+                         DRY KILN SPECIALTIES
+
+Kiln Cars and Method of Loading Same--The "Cross-wise" Piling
+Method--The "End-wise" Piling Method--The "Edge-wise"
+Piling Method--The Automatic Lumber Stacker--The Unstacker
+Car--Stave Piling--Shingle Piling--Stave Bolt Trucks--Different
+Types of Kiln Cars--Different Types of Transfer Cars--Dry Kiln
+Doors--Different Types of Kiln Door Carriers                     206-236
+
+                              SECTION XIV
+
+                   HELPFUL APPLIANCES IN KILN DRYING
+
+The Humidity Diagram--Examples of Use--The Hygrodeik--The
+Recording Hygrometer--The Registering Hygrometer--The
+Recording Thermometer--The Registering Thermometer--The
+Recording Steam Gauge--The Troemroid Scalometer--Test
+Samples--Weighing--Examples of Use--Records of Moisture
+Content--Saw Mills--Factories--The Electric Heater               237-250
+
+                              SECTION XV
+
+Bibliography--Glossary--Index of Latin Names--Index of Common
+Names                                                            251-257
+
+
+
+
+                         LIST OF ILLUSTRATIONS
+
+ FIG.                                                               PAGE
+
+ 1. Board of pine                                                     13
+ 2. Wood of spruce                                                    14
+ 3. Group of fibres from pine wood                                    15
+ 4. Block of oak                                                      31
+ 5. Board of oak                                                      32
+ 6. Cross-section of oak highly magnified                             32
+ 7. Highly magnified fibres of wood                                   33
+ 8. Isolated fibres and cells of wood                                 34
+ 9. Cross-section of basswood                                         35
+10. A large red gum                                                   52
+11. A tupelo gum slough                                               53
+12. Second growth red gum                                             57
+13. A cypress slough in dry season                                    58
+14. A large cottonwood                                                78
+15. Spiral grain in wood                                              87
+16. Alternating spiral grain in cypress                               87
+17. Wavy grain in beech                                               88
+18. Section of wood showing position of the grain at base of limb     89
+19. Cross-section of a group of wood fibres                           91
+20. Isolated fibres of wood                                           91
+21. Orientation of wood samples                                       93
+22. Work of ambrosia beetles in tulip or yellow poplar               100
+23. Work of ambrosia beetles in oak                                  100
+24. Work of round-headed and flat-headed borers in pine              102
+25. Work of timber worms in oak                                      103
+26. Work of powder post borers in hickory poles                      104
+27. Work of powder post borers in hickory poles                      104
+28. Work of powder post borers in hickory handles                    105
+29. Work of round-headed borers in white pine staves                 111
+30. U. S. Forest Service humidity controlled dry kiln                161
+31. Section through moist-air dry kiln                               189
+32. Live steam single pipe heating apparatus                         190
+33. Live steam double pipe heating apparatus                         191
+34. Vertical Pipe heating apparatus                                  193
+35. Progressive dry kilns                                            197
+36. Apartment dry kilns                                              199
+37. Pocket dry kilns                                                 201
+38. Tower dry kiln                                                   203
+39. Box dry kiln                                                     205
+40. Edge-wise method of piling                                       206
+41. Edge-wise method of piling                                       207
+42. Automatic lumber stacker                                         208
+43. Automatic lumber stacker                                         208
+44. Battery of three automatic lumber stackers                       209
+45. Battery of three automatic lumber stackers                       209
+46. Lumber loaded edge-wise on kiln truck                            210
+47. The lumber unstacker                                             211
+48. The lumber unstacker car                                         211
+49. Method of piling veneer on edge                                  212
+50. Kiln truck loaded cross-wise of kiln                             213
+51. Kiln truck loaded cross-wise of kiln                             214
+52. Kiln truck loaded end-wise of kiln                               214
+53. Kiln truck loaded end-wise of kiln                               215
+54. Method of piling staves on kiln truck                            216
+55. Method of piling staves on kiln truck                            216
+56. Method of piling tub or pail staves on kiln truck                217
+57. Method of piling bundled staves on kiln truck                    217
+58. Method of piling shingles on kiln truck                          218
+59. Method of piling shingles on kiln truck                          218
+60. Method of piling shingles on kiln truck                          219
+61. Kiln truck designed for loose pail staves                        219
+62. Kiln truck designed for handling short stock                     221
+63. Stave bolt truck                                                 221
+64. Stave bolt truck                                                 222
+65. Stave bolt truck                                                 222
+66. Stave bolt truck                                                 223
+67. Stave bolt truck                                                 223
+68. Stave bolt truck                                                 224
+69. Regular 3-rail transfer car                                      224
+70. Regular 3-rail transfer car                                      225
+71. Special 4-rail transfer car                                      225
+72. Regular 2-rail transfer car                                      225
+73. Regular 2-rail transfer car                                      226
+74. Underslung type 3-rail transfer car                              226
+75. Underslung type 2-rail transfer car                              226
+76. Flexible type 2-rail transfer car                                227
+77. Regular transfer car for stave bolt trucks                       228
+78. Regular transfer car for stave bolt trucks                       228
+79. Special transfer car for stave bolt trucks                       228
+80. Regular channel iron kiln truck for cross-wise piling            229
+81. Regular channel iron kiln truck for cross-wise piling            229
+82. Regular channel iron kiln truck for end-wise piling              230
+83. Special channel iron kiln truck for end-wise piling              230
+84. Regular dolly kiln truck for end-wise piling                     230
+85. Asbestos-lined kiln door                                         231
+86. Twin door carrier with door loaded                               232
+87. Twin door carrier for doors 18 to 35 feet wide                   232
+88. Kiln door carrier                                                233
+89. Kiln door construction                                           234
+90. Kiln door construction                                           235
+91. Kiln door construction                                           235
+92. Kiln door construction                                           236
+93. The Humidity diagram                                  _facing_   237
+94. The hygrodeik                                                    242
+95. The recording hygrometer                                         243
+96. The registering hygrometer                                       244
+97. The recording thermometer                                        245
+98. The registering thermometer                                      246
+99. The recording steam gauge                                        246
+100. The troemroid scalometer                                        247
+101. The electric heater                                             250
+
+
+
+
+                           SEASONING OF WOOD
+
+
+
+
+                               SECTION I
+
+                                TIMBER
+
+                    Characteristics and Properties
+
+
+Timber was probably one of the earliest, if not the earliest, of
+materials used by man for constructional purposes. With it he built
+for himself a shelter from the elements; it provided him with fuel and
+oft-times food, and the tree cut down and let across a stream formed
+the first bridge. From it, too, he made his "dug-out" to travel along
+and across the rivers of the district in which he dwelt; so on down
+through the ages, for shipbuilding and constructive purposes, timber
+has continued to our own time to be one of the most largely used of
+nature's products.
+
+Although wood has been in use so long and so universally, there still
+exists a remarkable lack of knowledge regarding its nature, not only
+among ordinary workmen, but among those who might be expected to know
+its properties. Consequently it is often used in a faulty and wasteful
+manner. Experience has been almost the only teacher, and
+theories--sometimes right, sometimes wrong--rather than well
+substantiated facts, lead the workman.
+
+One reason for this imperfect knowledge lies in the fact that wood is
+not a homogeneous material, but a complicated structure, and so
+variable, that one piece will behave very differently from another,
+although cut from the same tree. Not only does the wood of one species
+differ from that of another, but the butt cut differs from that of the
+top log, the heartwood from the sapwood; the wood of quickly-grown
+sapling of the abandoned field, from that of the slowly-grown, old
+monarch of the forest. Even the manner in which the tree was cut and
+kept influences its behavior and quality. It is therefore extremely
+difficult to study the material for the purpose of establishing
+general laws.
+
+The experienced woodsman will look for straight-grained, long-fibred
+woods, with the absence of disturbing resinous and coloring matter,
+knots, etc., and will quickly distinguish the more porous red or black
+oaks from the less porous white species, _Quercus alba_. That the
+inspection should have regard to defects and unhealthy conditions
+(often indicated by color) goes without saying, and such inspection is
+usually practised. That knots, even the smallest, are defects, which
+for some uses condemn the material entirely, need hardly be mentioned.
+But that "season-checks," even those that have closed by subsequent
+shrinkage, remain elements of weakness is not so readily appreciated;
+yet there cannot be any doubt of this, since these, the intimate
+connections of the wood fibres, when once interrupted are never
+reestablished.
+
+Careful woods-foremen and manufacturers, therefore, are concerned as
+to the manner in which their timber is treated after the felling, for,
+according to the more or less careful seasoning of it, the season
+checks--not altogether avoidable--are more or less abundant.
+
+There is no country where wood is more lavishly used or criminally
+neglected than in the United States, and none in which nature has more
+bountifully provided for all reasonable requirements.
+
+In the absence of proper efforts to secure reproduction, the most
+valuable kinds are rapidly being decimated, and the necessity of a
+more rational and careful use of what remains is clearly apparent. By
+greater care in selection, however, not only will the duration of the
+supply be extended, but more satisfactory results will accrue from its
+practice.
+
+There are few more extensive and wide-reaching subjects on which to
+treat than timber, which in this book refers to dead timber--the
+timber of commerce--as distinct from the living tree. Such a great
+number of different kinds of wood are now being brought from various
+parts of the world, so many new kinds are continually being added, and
+the subject is more difficult to explain because timber of practically
+the same character which comes from different localities goes under
+different names, that if one were always to adhere to the botanical
+name there would be less confusion, although even botanists differ in
+some cases as to names. Except in the cases of the older and better
+known timbers, one rarely takes up two books dealing with timber and
+finds the botanical names the same; moreover, trees of the same
+species may produce a much poorer quality of timber when obtained from
+different localities in the same country, so that botanical knowledge
+will not always allow us to dispense with other tests.
+
+The structure of wood affords the only reliable means of
+distinguishing the different kinds. Color, weight, smell, and other
+appearances, which are often direct or indirect results of structure,
+may be helpful in this distinction, but cannot be relied upon
+entirely. Furthermore, structure underlies nearly all the technical
+properties of this important product, and furnishes an explanation why
+one piece differs in these properties from another. Structure explains
+why oak is heavier, stronger, and tougher than pine; why it is harder
+to saw and plane, and why it is so much more difficult to season
+without injury. From its less porous structure alone it is evident
+that a piece of young and thrifty oak is stronger than the porous wood
+of an old or stunted tree, or that a Georgia or long-leaf pine excels
+white pine in weight and strength.
+
+Keeping especially in mind the arrangement and direction of the fibres
+of wood, it is clear at once why knots and "cross-grain" interfere
+with the strength of timber. It is due to the structural peculiarities
+that "honeycombing" occurs in rapid seasoning, that checks or cracks
+extend radially and follow pith rays, that tangent or "bastard" cut
+stock shrinks and warps more than that which is quarter-sawn. These
+same peculiarities enable oak to take a better finish than basswood or
+coarse-grained pine.
+
+
+                           Structure of Wood
+
+The softwoods are made up chiefly of tracheids, or vertical cells
+closed at the ends, and of the relatively short parenchyma cells of
+the medullary rays which extend radially from the heart of the tree.
+The course of the tracheids and the rays are at right angles to each
+other. Although the tracheids have their permeable portions or pits in
+their walls, liquids cannot pass through them with the greatest ease.
+The softwoods do not contain "pores" or vessels and are therefore
+called "non-porous" woods.
+
+The hardwoods are not so simple in structure as softwoods. They
+contain not only rays, and in many cases tracheids, but also
+thick-walled cells called fibres and wood parenchyma for the storage
+of such foods as starches and sugars. The principal structural
+features of the hardwoods are the pores or vessels. These are long
+tubes, the segments of which are made up of cells which have lost
+their end walls and joined end to end, forming continuous "pipe lines"
+from the roots to the leaves in the tree. Since they possess pores or
+vessels, the hardwoods are called "porous" woods.
+
+Red oak is an excellent example of a porous wood. In white oak the
+vessels of the heartwood especially are closed, very generally by
+ingrowths called tyloses. This probably explains why red oak dries
+more easily and rapidly than white oak.
+
+The red and black gums are perhaps the simplest of the hardwoods in
+structure. They are termed "diffuse porous" woods because of the
+numerous scattered pores they contain. They have only vessels, wood
+fibres, and a few parenchyma cells. The medullary rays, although
+present, are scarcely visible in most instances. The vessels are in
+many cases open, and might be expected to offer relatively little
+resistance to drying.
+
+
+                          Properties of Wood
+
+Certain general properties of wood may be discussed briefly. We know
+that wood substance has the property of taking in moisture from the
+air until some balance is reached between the humidity of the air and
+the moisture in the wood. This moisture which goes into the cell walls
+hygroscopic moisture, and the property which the wood substance has of
+taking on hygroscopic moisture is termed hygroscopicity. Usually wood
+contains not only hygroscopic moisture but also more or less free
+water in the cell cavities. Especially is this true of sapwood. The
+free water usually dries out quite rapidly with little or no shrinkage
+or other physical change.
+
+In certain woods--for example, _Eucalyptus globulus_ and possibly some
+oaks--shrinkage begins almost at once, thus introducing a factor at
+the very start of the seasoning process which makes these woods very
+refractory.
+
+The cell walls of some species, including the two already mentioned,
+such as Western red cedar and redwood, become soft and plastic when
+hot and moist. If the fibres are hot enough and very wet, they are not
+strong enough to withstand the resulting force of the atmospheric
+pressure and the tensile force exerted by the departing free water,
+and the result is that the cells actually collapse.
+
+In general, however, the hygroscopic moisture necessary to saturate
+the cell walls is termed the "fibre saturation point." This amount has
+been found to be from 25 to 30 per cent of the dry wood weight. Unlike
+_Eucalyptus globulus_ and certain oaks, the gums do not begin to
+shrink until the moisture content has been reduced to about 30 per
+cent of the dry wood weight. These woods are not subject to collapse,
+although their fibres become very plastic while hot and moist.
+
+Upon the peculiar properties of each wood depends the difficulty or
+ease of the seasoning process.
+
+
+                           Classes of Trees
+
+The timber of the United States is furnished by three well-defined
+classes of trees: (1) The needle-leaved, naked-seeded conifers, such
+as pine, cedar, etc., (2) the broad-leaved trees such as oak poplar,
+etc., and (3) to an inferior extent by the (one-seed leaf) palms,
+yuccas, and their allies, which are confined to the most southern
+parts of the country.
+
+Broad-leaved trees are also known as deciduous trees, although,
+especially in warm countries, many of them are evergreen, while the
+needle-leaved trees (conifers) are commonly termed "evergreens,"
+although the larch, bald cypress, and others shed their leaves every
+fall, and even the names "broad-leaved" and "coniferous," though
+perhaps the most satisfactory, are not at all exact, for the conifer
+"ginkgo" has broad leaves and bears no cones.
+
+Among the woodsmen, the woods of broad-leaved trees are known as
+"hardwoods," though poplar is as soft as pine, and the "coniferous
+woods" are known as "softwoods," notwithstanding the fact that yew
+ranks high in hardness even when compared with "hardwoods."
+
+Both in the number of different kinds of trees or species and still
+more in the importance of their product, the conifers and broad-leaved
+trees far excel the palms and their relatives.
+
+In the manner of their growth both the conifers and broad-leaved trees
+behave alike, adding each year a new layer of wood, which covers the
+old wood in all parts of the stem and limbs. Thus the trunk continues
+to grow in thickness throughout the life of the tree by additions
+(annual rings), which in temperate climates are, barring accidents,
+accurate records of the tree. With the palms and their relatives the
+stem remains generally of the same diameter, the tree of a hundred
+years old being as thick as it was at ten years, the growth of these
+being only at the top. Even where a peripheral increase takes place,
+as in the yuccas, the wood is not laid on in well-defined layers for
+the structure remains irregular throughout. Though alike in the manner
+of their growth, and therefore similar in their general make-up,
+conifers and broad-leaved trees differ markedly in the details of
+their structure and the character of their wood.
+
+The wood of all conifers is very simple in its structure, the fibres
+composing the main part of the wood all being alike and their
+arrangement regular. The wood of the broad-leaved trees is complex in
+structure; it is made up of different kinds of cells and fibres and
+lacks the regularity of arrangement so noticeable in the conifers.
+This difference is so great that in a study of wood structure it is
+best to consider the two kinds separately.
+
+In this country the great variety of woods, and especially of useful
+woods, often makes the mere distinction of the kind or species of tree
+most difficult. Thus there are at least eight pines of the thirty-five
+native ones in the market, some of which so closely resemble each
+other in their minute structure that one can hardly tell them apart,
+and yet they differ in quality and are often mixed or confounded in
+the trade. Of the thirty-six oaks, of which probably not less than six
+or eight are marketed, we can readily recognize by means of their
+minute anatomy at least two tribes--the white and black oaks. The same
+is true of the eleven kinds of hickory, the six kinds of ash, etc.,
+etc.
+
+The list of names of all trees indigenous to the United States, as
+enumerated by the United States Forest Service, is 495 in number, the
+designation of "tree" being applied to all woody plants which produce
+naturally in their native habitat one main, erect stem, bearing a
+definite crown, no matter what size they attain.
+
+Timber is produced only by the Spermatophyta, or seed-bearing plants,
+which are subdivided into the Gymnosperms (conifers), and Angiosperms
+(broad-leaved). The conifer or cone-bearing tree, to which belong the
+pines, larches, and firs, is one of the three natural orders of
+Gymnosperms. These are generally classed as "softwoods," and are more
+extensively scattered and more generally used than any other class of
+timber, and are simple and regular in structure. The so-called
+"hardwoods" are "Dicotyledons" or broad-leaved trees, a subdivision of
+the Angiosperms. They are generally of slower growth, and produce
+harder timber than the conifers, but not necessarily so. Basswood,
+poplar, sycamore, and some of the gums, though classed with the
+hardwoods, are not nearly as hard as some of the pines.
+
+
+
+
+                              SECTION II
+
+                           CONIFEROUS TREES
+
+                     WOOD OF THE CONIFEROUS TREES
+
+
+Examining a smooth cross-section or end face of a well-grown log of
+Georgia pine, we distinguish an envelope of reddish, scaly bark, a
+small, whitish pith at the center, and between these the wood in a
+great number of concentric rings.
+
+
+                             Bark and Pith
+
+The bark of a pine stem is thickest and roughest near the base,
+decreases rapidly in thickness from one to one-half inches at the
+stump to one-tenth inch near the top of the tree, and forms in general
+about ten to fifteen per cent of the entire trunk. The pith is quite
+thick, usually one-eighth to one-fifth inch in southern species,
+though much less so in white pine, and is very thin, one-fifteenth to
+one twenty-fifth inch in cypress, cedar, and larch.
+
+In woods with a thick pith, the pith is finest at the stump, grows
+rapidly thicker toward the top, and becomes thinner again in the crown
+and limbs, the first one to five rings adjoining it behaving
+similarly.
+
+What is called the pith was once the seedling tree, and in many of the
+pines and firs, especially after they have been seasoning for a good
+while, this is distinctly noticeable in the center of the log, and
+detaches itself from the surrounding wood.
+
+
+                           Sap and Heartwood
+
+Wood is composed of duramen or heartwood, and alburnum or sapwood, and
+when dry consists approximately of 49 per cent by weight of carbon, 6
+per cent of hydrogen, 44 per cent of oxygen, and 1 per cent of ash,
+which is fairly uniform for all species. The sapwood is the external
+and youngest portion of the tree, and often constitutes a very
+considerable proportion of it. It lies next the bark, and after a
+course of years, sometimes many, as in the case of oaks, sometimes
+few, as in the case of firs, it becomes hardened and ultimately forms
+the duramen or heartwood. Sapwood is generally of a white or light
+color, almost invariably lighter in color than the heartwood, and is
+very conspicuous in the darker-colored woods, as for instance the
+yellow sapwood of mahogany and similiar colored woods, and the reddish
+brown heartwood; or the yellow sapwood of _Lignum-vitae_ and the dark
+green heartwood. Sapwood forms a much larger proportion of some trees
+than others, but being on the outer circumference it always forms a
+large proportion of the timber, and even in sound, hard pine will be
+from 40 per cent to 60 per cent of the tree and in some cases much
+more. It is really imperfect wood, while the duramen or heartwood is
+the perfect wood; the heartwood of the mature tree was the sapwood of
+its earlier years. Young trees when cut down are almost all sapwood,
+and practically useless as good, sound timber; it is, however, through
+the sapwood that the life-giving juices which sustain the tree arise
+from the soil, and if the sapwood be cut through, as is done when
+"girdling," the tree quickly dies, as it can derive no further
+nourishment from the soil. Although absolutely necessary to the
+growing tree, sapwood is often objectionable to the user, as it is the
+first part to decay. In this sapwood many cells are active, store up
+starch, and otherwise assist in the life processes of the tree,
+although only the last or outer layer of cells forms the growing part,
+and the true life of the tree.
+
+The duramen or heartwood is the inner, darker part of the log. In the
+heartwood all the cells are lifeless cases, and serve only the
+mechanical function of keeping the tree from breaking under its own
+great weight or from being laid low by the winds. The darker color of
+the heartwood is due to infiltration of chemical substances into the
+cell walls, but the cavities of the cells in pine are not filled up,
+as is sometimes believed, nor do their walls grow thicker, nor are the
+walls any more liquified than in the sapwood.
+
+Sapwood varies in width and in the number of rings which it contains
+even in different parts of the same tree. The same year's growth which
+is sapwood in one part of a disk may be heartwood in another. Sapwood
+is widest in the main part of the stem and often varies within
+considerable limits and without apparent regularity. Generally, it
+becomes narrower toward the top and in the limbs, its width varying
+with the diameter, and being the least in a given disk on the side
+which has the shortest radius. Sapwood of old and stunted pines is
+composed of more rings than that of young and thrifty specimens. Thus
+in a pine two hundred and fifty years old a layer of wood or an annual
+ring does not change from sapwood to heartwood until seventy or eighty
+years after it is formed, while in a tree one hundred years old or
+less it remains sapwood only from thirty to sixty years.
+
+The width of the sapwood varies considerably for different kinds of
+pine. It is small for long-leaf and white pine and great for loblolly
+and Norway pines. Occupying the peripheral part of the trunk, the
+proportion which it forms of the entire mass of the stem is always
+great. Thus even in old long-leaf pines, the sapwood forms 40 per cent
+of the merchantable log, while in the loblolly and in all young trees
+the sapwood forms the bulk of the wood.
+
+
+                      The Annual or Yearly Rings
+
+The concentric annual or yearly rings which appear on the end face of
+a log are cross-sections of so many thin layers of wood. Each such
+layer forms an envelope around its inner neighbor, and is in turn
+covered by the adjoining layer without, so that the whole stem is
+built up of a series of thin, hollow cylinders, or rather cones.
+
+A new layer of wood is formed each season, covering the entire stem,
+as well as all the living branches. The thickness of this layer or the
+width of the yearly ring varies greatly in different trees, and also
+in different parts of the same tree.
+
+In a normally-grown, thrifty pine log the rings are widest near the
+pith, growing more and more narrow toward the bark. Thus the central
+twenty rings in a disk of an old long-leaf pine may each be one-eighth
+to one-sixth inch wide, while the twenty rings next to the bark may
+average only one-thirtieth inch.
+
+In our forest trees, rings of one-half inch in width occur only near
+the center in disks of very thrifty trees, of both conifers and
+hardwoods. One-twelfth inch represents good, thrifty growth, and the
+minimum width of one two hundred inch is often seen in stunted spruce
+and pine. The average width of rings in well-grown, old white pine
+will vary from one-twelfth to one-eighteenth inch, while in the slower
+growing long-leaf pine it may be one twenty-fifth to one-thirtieth of
+an inch. The same layer of wood is widest near the stump in very
+thrifty young trees, especially if grown in the open park; but in old
+forest trees the same year's growth is wider at the upper part of the
+tree, being narrowest near the stump, and often also near the very tip
+of the stem. Generally the rings are widest near the center, growing
+narrower toward the bark.
+
+In logs from stunted trees the order is often reversed, the interior
+rings being thin and the outer rings widest. Frequently, too, zones or
+bands of very narrow rings, representing unfavorable periods of
+growth, disturb the general regularity.
+
+Few trees, even among pines, furnish a log with truly circular
+cross-section. Usually it is an oval, and at the stump commonly quite
+an irregular figure. Moreover, even in very regular or circular disks
+the pith is rarely in the center, and frequently one radius is
+conspicuously longer than its opposite, the width of some rings, if
+not all, being greater on one side than on the other. This is nearly
+always so in the limbs, the lower radius exceeding the upper. In
+extreme cases, especially in the limbs, a ring is frequently
+conspicuous on one side, and almost or entirely lost to view on the
+other. Where the rings are extremely narrow, the dark portion of the
+ring is often wanting, the color being quite uniform and light. The
+greater regularity or irregularity of the annual rings has much to do
+with the technical qualities of the timber.
+
+
+                        Spring- and Summer-Wood
+
+Examining the rings more closely, it is noticed that each ring is made
+up of an inner, softer, light-colored and an outer, or peripheral,
+firmer and darker-colored portion. Being formed in the forepart of the
+season, the inner, light-colored part is termed spring-wood, the
+outer, darker-portioned being the summer-wood of the ring. Since the
+latter is very heavy and firm it determines to a very large extent the
+weight and strength of the wood, and as its darker color influences
+the shade of color of the entire piece of wood, this color effect
+becomes a valuable aid in distinguishing heavy and strong from light
+and soft pine wood.
+
+In most hard pines, like the long-leaf, the dark summer-wood appears
+as a distinct band, so that the yearly ring is composed of two sharply
+defined bands--an inner, the spring-wood, and an outer, the
+summer-wood. But in some cases, even in hard pines, and normally in
+the woods of white pines, the spring-wood passes gradually into the
+darker summer-wood, so that a darkly defined line occurs only where
+the spring-wood of one ring abuts against the summer-wood of its
+neighbor. It is this clearly defined line which enables the eye to
+distinguish even the very narrow lines in old pines and spruces.
+
+In some cases, especially in the trunks of Southern pines, and
+normally on the lower side of pine limbs, there occur dark bands of
+wood in the spring-wood portion of the ring, giving rise to false
+rings, which mislead in a superficial counting of rings. In the disks
+cut from limbs these dark bands often occupy the greater part of the
+ring, and appear as "lunes," or sickle-shaped figures. The wood of
+these dark bands is similar to that of the true summer-wood. The cells
+have thick walls, but usually the compressed or flattened form.
+Normally, the summer-wood forms a greater proportion of the rings in
+the part of the tree formed during the period of thriftiest growth. In
+an old tree this proportion is very small in the first two to five
+rings about the pith, and also in the part next to the bark, the
+intermediate part showing a greater proportion of summer-wood. It is
+also greatest in a disk taken from near the stump, and decreases
+upward in the stem, thus fully accounting for the difference in weight
+and firmness of the wood of these different parts.
+
+    [Illustration: Fig. 1. Board of Pine. CS, cross-section; RS,
+    radial section; TS, tangential section; _sw_, summer-wood;
+    _spw_, spring-wood.]
+
+In the long-leaf pine the summer-wood often forms scarcely ten per
+cent of the wood in the central five rings; forty to fifty per cent of
+the next one hundred rings, about thirty per cent of the next fifty,
+and only about twenty per cent in the fifty rings next to the bark. It
+averages forty-five per cent of the wood of the stump and only
+twenty-four per cent of that of the top.
+
+Sawing the log into boards, the yearly rings are represented on the
+board faces of the middle board (radial sections) by narrow parallel
+strips (see Fig. 1), an inner, lighter stripe and its outer, darker
+neighbor always corresponding to one annual ring.
+
+On the faces of the boards nearest the slab (tangential or bastard
+boards) the several years' growth should also appear as parallel, but
+much broader stripes. This they do if the log is short and very
+perfect. Usually a variety of pleasing patterns is displayed on the
+boards, depending on the position of the saw cut and on the regularity
+of growth of the log (see Fig. 1). Where the cut passes through a
+prominence (bump or crook) of the log, irregular, concentric circlets
+and ovals are produced, and on almost all tangent boards arrow or
+V-shaped forms occur.
+
+
+                         Anatomical Structure
+
+Holding a well-smoothed disk or cross-section one-eighth inch thick
+toward the light, it is readily seen that pine wood is a very porous
+structure. If viewed with a strong magnifier, the little tubes,
+especially in the spring-wood of the rings, are easily distinguished,
+and their arrangement in regular, straight, radial rows is apparent.
+
+    [Illustration: Fig. 2. Wood of Spruce. 1, natural size; 2,
+    small part of one ring magnified 100 times. The vertical
+    tubes are wood fibres, in this case all "tracheids." _m_,
+    medullary or pith ray; _n_, transverse tracheids of ray; _a_,
+    _b_, and _c_, bordered pits of the tracheids, more enlarged.]
+
+Scattered through the summer-wood portion of the rings, numerous
+irregular grayish dots (the resin ducts) disturb the uniformity and
+regularity of the structure. Magnified one hundred times, a piece of
+spruce, which is similar to pine, presents a picture like that shown
+in Fig. 2. Only short pieces of the tubes or cells of which the wood
+is composed are represented in the picture. The total length of these
+fibres is from one-twentieth to one-fifth inch, being the smallest
+near the pith, and is fifty to one hundred times as great as their
+width (see Fig. 3). They are tapered and closed at their ends,
+polygonal or rounded and thin-walled, with large cavity, lumen or
+internal space in the spring-wood, and thick-walled and flattened
+radially, with the internal space or lumen much reduced in the
+summer-wood (see right-hand portion of Fig. 2). This flattening,
+together with the thicker walls of the cells, which reduces the lumen,
+causes the greater firmness and darker color of the summer-wood.
+There is more material in the same volume. As shown in the figure, the
+tubes, cells or "tracheids" are decorated on their walls by
+circlet-like structures, the "bordered pits," sections of which are
+seen more magnified as _a_, _b_, and _c_, Fig. 2. These pits are in
+the nature of pores, covered by very thin membranes, and serve as
+waterways between the cells or tracheids. The dark lines on the side
+of the smaller piece (1, Fig. 2) appear when magnified (in 2, Fig. 2)
+as tiers of eight to ten rows of cells, which run radially (parallel
+to the rows of tubes or tracheids), and are seen as bands on the
+radial face and as rows of pores on the tangential face. These bands
+or tiers of cell rows are the medullary rays or pith rays, and are
+common to all our lumber woods.
+
+In the pines and other conifers they are quite small, but they can
+readily be seen even without a magnifier. If a radial surface of
+split-wood (not smoothed) is examined, the entire radial face will be
+seen almost covered with these tiny structures, which appear as fine
+but conspicuous cross-lines. As shown in Fig. 2, the cells of the
+medullary or pith are smaller and very much shorter than the wood
+fibre or tracheids, and their long axis is at right angles to that of
+the fiber.
+
+    [Illustration: Fig. 3. Group of Fibres from Pine Wood. Partly
+    schematic. The little circles are "border pits" (see Fig. 2,
+    _a-c_). The transverse rows of square pits indicate the
+    places of contact of these fibres and the cells of the
+    neighboring pith rays. Magnified about 25 times.]
+
+In pines and spruces the cells of the upper and lower rows of each
+tier or pith ray have "bordered" pits, like those of the wood fibre or
+tracheids proper, but the cells of the intermediate rows in the rays
+of cedars, etc., have only "simple" pits, _i.e._, pits devoid of the
+saucer-like "border" or rim. In pine, many of the pith rays are larger
+than the majority, each containing a whitish line, the horizontal
+resin duct, which, though much smaller, resembles the vertical ducts
+on the cross-section. The larger vertical resin ducts are best
+observed on removal of the bark from a fresh piece of white pine cut
+in the winter where they appear as conspicuous white lines, extending
+often for many inches up and down the stem. Neither the horizontal nor
+the vertical resin ducts are vessels or cells, but are openings
+between cells, _i.e._, intercellular spaces, in which the resin
+accumulates, freely oozing out when the ducts of a fresh piece of
+sapwood are cut. They are present only in our coniferous woods, and
+even here they are restricted to pine, spruce, and larch, and are
+normally absent in fir, cedar, cypress, and yew. Altogether, the
+structure of coniferous woods is very simple and regular, the bulk
+being made up of the small fibres called tracheids, the disturbing
+elements of pith rays and resin ducts being insignificant, and hence
+the great uniformity and great technical value of coniferous woods.
+
+
+
+
+                  LIST OF IMPORTANT CONIFEROUS WOODS
+
+
+                                 CEDAR
+
+Light soft, stiff, not strong, of fine texture. Sap- and heartwood
+distinct, the former lighter, the latter a dull grayish brown or red.
+The wood seasons rapidly, shrinks and checks but little, and is very
+durable in contact with the soil. Used like soft pine, but owing to
+its great durability preferred for shingles, etc. Cedars usually occur
+scattered, but they form in certain localities forests of considerable
+extent.
+
+
+                          (_a_) White Cedars
+
+=1. White Cedar= (_Thuya occidentalis_) (Arborvitae, Tree of Life).
+Heartwood light yellowish brown, sapwood nearly white. Wood light,
+soft, not strong, of fine texture, very durable in contact with the
+soil, very fragrant. Scattered along streams and lakes, frequently
+covering extensive swamps; rarely large enough for lumber, but
+commonly used for fence posts, rails, railway ties, and shingles. This
+species has been extensively cultivated as an ornamental tree for at
+least a century. Maine to Minnesota and northward.
+
+=2. Canoe Cedar= (_Thuya gigantea_) (Red Cedar of the West). In Oregon
+and Washington a very large tree, covering extensive swamps; in the
+mountains much smaller, skirting the water courses. An important
+lumber tree. The wood takes a fine polish; suitable for interior
+finishing, as there is much variety of shading in the color.
+Washington to northern California and eastward to Montana.
+
+=3. White Cedar= (_Chamaecyparis thyoides_). Medium-sized tree. Heartwood
+light brown with rose tinge, sapwood paler. Wood light, soft, not
+strong, close-grained, easily worked, very durable in contact with the
+soil and very fragrant. Used in boatbuilding cooperage, interior
+finish, fence posts, railway ties, etc. Along the coast from Maine to
+Mississippi.
+
+=4. White Cedar= (_Chamaecyparis Lawsoniana_) (Port Orford Cedar, Oregon
+Cedar, Lawson's Cypress, Ginger Pine). A very large tree. A fine,
+close-grained, yellowish-white, durable timber, elastic, easily
+worked, free of knots, and fragrant. Extensively cut for lumber;
+heavier and stronger than any of the preceding. Along the coast line
+of Oregon.
+
+=5. White Cedar= (_Libocedrus decurrens_) (Incense Cedar). A large tree,
+abundantly scattered among pine and fir. Wood fine-grained. Cascades
+and Sierra Nevada Mountains of Oregon and California.
+
+=6. Yellow Cedar= (_Cupressus nootkatensis_) (Alaska Cedar, Alaska
+Cypress). A very large tree, much used for panelling and furniture. A
+fine, close-grained, yellowish white, durable timber, easily worked.
+Along the coast line of Oregon north.
+
+
+                           (_b_) Red Cedars
+
+=7. Red Cedar= (_Juniperus Virginiana_) (Savin Juniper, Juniper, Red
+Juniper, Juniper Bush, Pencil Cedar). Heartwood dull red color, thin
+sapwood nearly white. Close even grain, compact structure. Wood light,
+soft, weak, brittle, easily worked, durable in contact with the soil,
+and fragrant. Used for ties, posts, interior finish, pencil cases,
+cigar boxes, silos, tanks, and especially for lead pencils, for which
+purpose alone several million feet are cut each year. A small to
+medium-sized tree scattered through the forests, or in the West
+sparsely covering extensive areas (cedar brakes). The red cedar is the
+most widely distributed conifer of the United States, occurring from
+the Atlantic to the Pacific, and from Florida to Minnesota. Attains a
+suitable size for lumber only in the Southern, and more especially the
+Gulf States.
+
+=8. Red Cedar= (_Juniperus communis_) (Ground Cedar). Small-sized tree,
+its maximum height being about 25 feet. It is found widely distributed
+throughout the Northern hemisphere. Wood in its quality similar to the
+preceding. The fruit of this species is gathered in large quantities
+and used in the manufacture of gin; whose peculiar flavor and
+medicinal properties are due to the oil of Juniper berries, which is
+secured by adding the crushed fruit to undistilled grain spirit, or by
+allowing the vapor to pass over it before condensation. Used locally
+for construction purposes, fence posts, etc. Ranges from Greenland to
+Alaska, in the East, southward to Pennsylvania and northern Nebraska;
+in the Rocky Mountains to Texas, Mexico, and Arizona.
+
+=9. Redwood= (_Sequoia sempervirens_) (Sequoia, California Redwood,
+Coast Redwood). Wood in its quality and uses like white cedar. Thick,
+red heartwood, changing to reddish brown when seasoned. Thin sapwood,
+nearly white, coarse, straight grain, compact structure. Light, not
+strong, soft, very durable in contact with the soil, not resinous,
+easily worked, does not burn easily, receives high polish. Used for
+timber, shingles, flumes, fence posts, coffins, railway ties, water
+pipes, interior decorations, and cabinetmaking. A very large tree,
+limited to the coast ranges of California, and forming considerable
+forests, which are rapidly being converted into lumber.
+
+
+                                CYPRESS
+
+=10. Cypress= (_Taxodium distinchum_) (Bald Cypress, Black, White, and
+Red Cypress, Pecky Cypress). Wood in its appearance, quality, and uses
+similar to white cedar. "Black" and "White Cypress" are heavy and
+light forms of the same species. Heartwood brownish; sapwood nearly
+white. Wood close, straight-grain, frequently full of small holes
+caused by disease known as "pecky cypress." Greasy appearance and
+feeling. Wood light, soft, not strong, durable in contact with the
+soil, takes a fine polish. Green wood often very heavy. Used for
+carpentry, building construction, shingles, cooperage, railway ties,
+silos, tanks, vehicles, and washing machines. The cypress is a large,
+deciduous tree, inhabiting swampy lands, and along rivers and coasts
+of the Southern parts of the United States. Grows to a height of 150
+feet and 12 feet in diameter.
+
+
+                                  FIR
+
+This name is frequently applied to wood and to trees which are not
+fir; most commonly to spruce, but also, especially in English markets,
+to pine. It resembles spruce, but is easily distinguished from it, as
+well as from pine and larch, by the absence of resin ducts. Quality,
+uses, and habits similar to spruce.
+
+=11. Balsam Fir= (_Abies balsamea_) (Balsam, Fir Tree, Balm of Gilead
+Fir). Heartwood white to brownish; sapwood lighter color;
+coarse-grained, compact structure, satiny. Wood light, not durable or
+strong, resinous, easily split. Used for boxes, crates, doors,
+millwork, cheap lumber, paper pulp. Inferior to white pine or spruce,
+yet often mixed and sold with these species in the lumber market. A
+medium-sized tree scattered throughout the northern pineries, and cut
+in lumber operations whenever of sufficient size. Minnesota to Maine
+and northward.
+
+=12. White Fir= (_Abies grandis_ and _Abies concolor_). Medium-to very
+large-sized tree, forming an important part of most of the Western
+mountain forests, and furnishes much of the lumber of the respective
+regions. The former occurs from Vancouver to California, and the
+latter from Oregon to Arizona and eastward to Colorado and Mexico. The
+wood is soft and light, coarse-grained, not unlike the "Swiss pine" of
+Europe, but darker and firmer, and is not suitable for any purpose
+requiring strength. It is used for boxes, barrels, and to a small
+extent for wood pulp.
+
+=13. White Fir= (_Abies amabalis_). Good-sized tree, often forming
+extensive mountain forests. Wood similar in quality and uses to _Abies
+grandis_. Cascade Mountains of Washington and Oregon.
+
+=14. Red Fir= (_Abies nobilis_) (Noble Fir) (not to be confounded with
+Douglas spruce. See No. 40). Large to very large-sized tree, forming
+extensive forests on the slope of the mountains between 3,000 and
+4,000 feet elevation. Cascade Mountains of Oregon.
+
+=15. Red Fir= (_Abies magnifica_). Very large-sized tree, forming
+forests about the base of Mount Shasta. Sierra Nevada Mountains of
+California, from Mount Shasta southward.
+
+
+                                HEMLOCK
+
+Light to medium weight, soft, stiff, but brittle, commonly
+cross-grained, rough and splintery. Sapwood and heartwood not well
+defined. The wood of a light reddish-gray color, free from resin
+ducts, moderately durable, shrinks and warps considerably in drying,
+wears rough, retains nails firmly. Used principally for dimension
+stuff and timbers. Hemlocks are medium- to large-sized trees, commonly
+scattered among broad-leaved trees and conifers, but often forming
+forests of almost pure growth.
+
+=16. Hemlock= (_Tsuga canadensis_) (Hemlock Spruce, Peruche).
+Medium-sized tree, furnishes almost all the hemlock of the Eastern
+market. Maine to Wisconsin, also following the Alleghanies southward
+to Georgia and Alabama.
+
+=17. Hemlock= (_Tsuga mertensiana_). Large-sized tree, wood claimed to
+be heavier and harder than the Eastern species and of superior
+quality. Used for pulp wood, floors, panels, and newels. It is not
+suitable for heavy construction, especially where exposed to the
+weather, it is straight in grain and will take a good polish. Not
+adapted for use partly in and partly out of the ground; in fresh water
+as piles will last about ten years, but as it is softer than fir it is
+less able to stand driving successfully. Washington to California and
+eastward to Montana.
+
+
+                           LARCH or TAMARACK
+
+Wood like the best of hard pine both in appearance, quality, and uses,
+and owing to its great durability somewhat preferred in shipbuilding,
+for telegraph poles, and railway ties. In its structure it resembles
+spruce. The larches are deciduous trees, occasionally covering
+considerable areas, but usually scattered among other conifers.
+
+=18. Tamarack= (_Larix laricina_ var. _Americana_) (Larch, Black Larch,
+American Larch, Hacmatac). Heartwood light brown in color, sapwood
+nearly white, coarse conspicuous grain, compact structure, annual
+rings pronounced. Wood heavy, hard, very strong, durable in contact
+with the soil. Used for railway ties, fence posts, sills, ship
+timbers, telegraph poles, flagstaffs. Medium-sized tree, often
+covering swamps, in which case it is smaller and of poor quality.
+Maine to Minnesota, and southward to Pennsylvania.
+
+=19. Tamarack= (_Larix occidentalis_) (Western Larch, Larch).
+Large-sized trees, scattered, locally abundant. Is little inferior to
+oak in strength and durability. Heartwood of a light brown color with
+lighter sapwood, has a fine, slightly satiny grain, and is fairly free
+from knots; the annual rings are distant. Used for railway ties and
+shipbuilding. Washington and Oregon to Montana.
+
+
+                                 PINE
+
+Very variable, very light and soft in "soft" pine, such as white pine;
+of medium weight to heavy and quite hard in "hard" pine, of which the
+long-leaf or Georgia pine is the extreme form. Usually it is stiff,
+quite strong, of even texture, and more or less resinous. The sapwood
+is yellowish white; the heartwood orange brown. Pine shrinks
+moderately, seasons rapidly and without much injury; it works easily,
+is never too hard to nail (unlike oak or hickory); it is mostly quite
+durable when in contact with the soil, and if well seasoned is not
+subject to the attacks of boring insects. The heavier the wood, the
+darker, stronger, and harder it is, and the more it shrinks and checks
+when seasoning. Pine is used more extensively than any other wood. It
+is the principal wood in carpentry, as well as in all heavy
+construction, bridges, trestles, etc. It is also used in almost every
+other wood industry; for spars, masts, planks, and timbers in
+shipbuilding, in car and wagon construction, in cooperage and
+woodenware; for crates and boxes, in furniture work, for toys and
+patterns, water pipes, excelsior, etc. Pines are usually large-sized
+trees with few branches, the straight, cylindrical, useful stem
+forming by far the greatest part of the tree. They occur gregariously,
+forming vast forests, a fact which greatly facilitates their
+exploitation. Of the many special terms applied to pine as lumber,
+denoting sometimes differences in quality, the following deserve
+attention: "White pine," "pumpkin pine," "soft pine," in the Eastern
+markets refer to the wood of the white pine (_Pinus strobus_), and on
+the Pacific Coast to that of the sugar pine (_Pinus lambertiana_).
+"Yellow pine" is applied in the trade to all the Southern lumber
+pines; in the Northwest it is also applied to the pitch pine (_Pinus
+regida_); in the West it refers mostly to the bull pine (_Pinus
+ponderosa_). "Yellow long-leaf pine" (Georgia pine), chiefly used in
+advertisements, refers to the long-leaf Pine (_Pinus palustris_).
+
+
+                           (_a_) Soft Pines
+
+=20. White Pine= (_Pinus strobus_) (Soft Pine, Pumpkin Pine, Weymouth
+Pine, Yellow Deal). Large to very large-sized tree, reaching a height
+of 80 to 100 feet or more, and in some instances 7 or 8 feet in
+diameter. For the last fifty years the most important timber tree of
+the United States, furnishing the best quality of soft pine. Heartwood
+cream white; sapwood nearly white. Close straight grain, compact
+structure; comparatively free from knots and resin. Soft, uniform;
+seasons well; easy to work; nails without splitting; fairly durable in
+contact with the soil; and shrinks less than other species of pine.
+Paints well. Used for carpentry, construction, building, spars, masts,
+matches, boxes, etc., etc., etc.
+
+=21. Sugar Pine= (_Pinus lambertiana_) (White Pine, Pumpkin Pine, Soft
+Pine). A very large tree, forming extensive forests in the Rocky
+Mountains and furnishing most of the timber of the western United
+States. It is confined to Oregon and California, and grows at from
+1,500 to 8,000 feet above sea level. Has an average height of 150 to
+175 feet and a diameter of 4 to 5 feet, with a maximum height of 235
+feet and 12 feet in diameter. The wood is soft, durable,
+straight-grained, easily worked, very resinous, and has a satiny
+luster which makes it appreciated for interior work. It is extensively
+used for doors, blinds, sashes, and interior finish, also for
+druggists' drawers, owing to its freedom from odor, for oars,
+mouldings, shipbuilding, cooperage, shingles, and fruit boxes. Oregon
+and California.
+
+=22. White Pine= (_Pinus monticolo_). A large tree, at home in Montana,
+Idaho, and the Pacific States. Most common and locally used in
+northern Idaho.
+
+=23. White Pine= (_Pinus flexilis_). A small-sized tree, forming
+mountain forests of considerable extent and locally used. Eastern
+Rocky Mountain slopes, Montana to New Mexico.
+
+
+                           (_b_) Hard Pines
+
+=24. Long-Leaf Pine= (_Pinus palustris_) (Georgia Pine, Southern Pine,
+Yellow Pine, Southern Hard Pine, Long-straw Pine, etc.). Large-sized
+tree. This species furnishes the hardest and most durable as well as
+one of the strongest pine timbers in the market. Heartwood orange,
+sapwood lighter color, the annual rings are strongly marked, and it is
+full of resinous matter, making it very durable, but difficult to
+work. It is hard, dense, and strong, fairly free from knots,
+straight-grained, and one of the best timbers for heavy engineering
+work where great strength, long span, and durability are required.
+Used for heavy construction, shipbuilding, cars, docks, beams, ties,
+flooring, and interior decoration. Coast region from North Carolina to
+Texas.
+
+=25. Bull Pine= (_Pinus ponderosa_) (Yellow Pine, Western Yellow Pine,
+Western Pine, Western White Pine, California White Pine). Medium- to
+very large-sized tree, forming extensive forests in the Pacific and
+Rocky Mountain regions. Heartwood reddish brown, sapwood yellowish
+white, and there is often a good deal of it. The resinous smell of the
+wood is very remarkable. It is extensively used for beams, flooring,
+ceilings, and building work generally.
+
+=26. Bull Pine= (_Pinus Jeffreyi_) (Black Pine). Large-sized tree, wood
+resembles _Pinus ponderosa_ and replacing same at high altitudes. Used
+locally in California.
+
+=27. Loblolly Pine= (_Pinus taeda_) (Slash Pine, Old Field Pine, Rosemary
+Pine, Sap Pine, Short-straw Pine). A large-sized tree, forms extensive
+forests. Wider-ringed, coarser, lighter, softer, with more sapwood
+than the long-leaf pine, but the two are often confounded in the
+market. The more Northern tree produces lumber which is weak, brittle,
+coarse-grained, and not durable, the Southern tree produces a better
+quality wood. Both are very resinous. This is the common lumber pine
+from Virginia to South Carolina, and is found extensively in Arkansas
+and Texas. Southern States, Virginia to Texas and Arkansas.
+
+=28. Norway Pine= (_Pinus resinosa_) (American Red Pine, Canadian Pine).
+Large-sized tree, never forming forests, usually scattered or in
+small groves, together with white pine. Largely sapwood and hence not
+durable. Heartwood reddish white, with fine, clear grain, fairly tough
+and elastic, not liable to warp and split. Used for building
+construction, bridges, piles, masts, and spars. Minnesota to Michigan;
+also in New England to Pennsylvania.
+
+=29. Short-Leaf Pine= (_Pinus echinata_) (Slash Pine, Spruce Pine,
+Carolina Pine, Yellow Pine, Old Field Pine, Hard Pine). A medium- to
+large-sized tree, resembling loblolly pine, often approaches in its
+wood the Norway pine. Heartwood orange, sapwood lighter; compact
+structure, apt to be variable in appearance in cross-section. Wood
+usually hard, tough, strong, durable, resinous. A valuable timber
+tree, sometimes worked for turpentine. Used for heavy construction,
+shipbuilding, cars, docks, beams, ties, flooring, and house trim.
+_Pinus echinata_, _palustris_, and _taeda_ are very similar in
+character, of thin wood and very difficult to distinguish one from
+another. As a rule, however, _palustris_ (Long-leaf Pine) has the
+smallest and most uniform growth rings, and _Pinus taeda_ (Loblolly
+Pine) has the largest. All are apt to be bunched together in the
+lumber market as Southern Hard Pine. All are used for the same
+purposes. Short-leaf is the common lumber pine of Missouri and
+Arkansas. North Carolina to Texas and Missouri.
+
+=30. Cuban Pine= (_Pinus cubensis_) (Slash Pine, Swamp Pine, Bastard
+Pine, Meadow Pine). Resembles long-leaf pine, but commonly has a wider
+sapwood and coarser grain. Does not enter the markets to any extent.
+Along the coast from South Carolina to Louisiana.
+
+=31. Pitch Pine= (_Pinus rigida_) (Torch Pine). A small to medium-sized
+tree. Heartwood light brown or red, sapwood yellowish white. Wood
+light, soft, not strong, coarse-grained, durable, very resinous. Used
+locally for lumber, fuel, and charcoal. Coast regions from New York
+to Georgia, and along the mountains to Kentucky.
+
+=32. Black Pine= (_Pinus murryana_) (Lodge-pole Pine, Tamarack).
+Small-sized tree. Rocky Mountains and Pacific regions.
+
+=33. Jersey Pine= (_Pinus inops_ var. _Virginiana_) (Scrub Pine).
+Small-sized tree. Along the coast from New York to Georgia and along
+the mountains to Kentucky.
+
+=34. Gray Pine= (_Pinus divaricata_ var. _banksiana_) (Scrub Pine, Jack
+Pine). Medium- to large-sized tree. Heartwood pale brown, rarely
+yellow; sapwood nearly white. Wood light, soft, not strong,
+close-grained. Used for fuel, railway ties, and fence posts. In days
+gone by the Indians preferred this species for frames of canoes.
+Maine, Vermont, and Michigan to Minnesota.
+
+
+                          REDWOOD (See Cedar)
+
+                                SPRUCE
+
+Resembles soft pine, is light, very soft, stiff, moderately strong,
+less resinous than pine; has no distinct heartwood, and is of whitish
+color. Used like soft pine, but also employed as resonance wood in
+musical instruments and preferred for paper pulp. Spruces, like pines,
+form extensive forests. They are more frugal, thrive on thinner soils,
+and bear more shade, but usually require a more humid climate. "Black"
+and "White" spruce as applied by lumbermen usually refer to narrow and
+wide-ringed forms of black spruce (_Picea nigra_).
+
+=35. Black Spruce= (_Picea nigra_ var. _mariana_). Medium-sized tree,
+forms extensive forests in northwestern United States and in British
+America; occurs scattered or in groves, especially in low lands
+throughout the northern pineries. Important lumber tree in eastern
+United States. Heartwood pale, often with reddish tinge; sapwood pure
+white. Wood light, soft, not strong. Chiefly used for manufacture of
+paper pulp, and great quantities of this as well as _Picea alba_ are
+used for this purpose. Used also for sounding boards for pianos,
+violins, etc. Maine to Minnesota, British America, and in the
+Alleghanies to North Carolina.
+
+=36. White Spruce= (_Picea canadensis_ var. _alba_). Medium- to
+large-sized tree. Heartwood light yellow; sapwood nearly white.
+Generally associated with the preceding. Most abundant along streams
+and lakes, grows largest in Montana and forms the most important tree
+of the sub-arctic forest of British America. Used largely for floors,
+joists, doors, sashes, mouldings, and panel work, rapidly superceding
+_Pinus strobus_ for building purposes. It is very similar to Norway
+pine, excels it in toughness, is rather less durable and dense, and
+more liable to warp in seasoning. Northern United States from Maine to
+Minnesota, also from Montana to Pacific, British America.
+
+=37. White Spruce= (_Picea engelmanni_). Medium- to large-sized tree,
+forming extensive forests at elevations from 5,000 to 10,000 feet
+above sea level; resembles the preceding, but occupies a different
+station. A very important timber tree in the central and southern
+parts of the Rocky Mountains. Rocky Mountains from Mexico to Montana.
+
+=38. Tide-Land Spruce= (_Picea sitchensis_) (Sitka Spruce). A
+large-sized tree, forming an extensive coast-belt forest. Used
+extensively for all classes of cooperage and woodenware on the Pacific
+Coast. Along the sea-coast from Alaska to central California.
+
+=39. Red Spruce= (_Picea rubens_). Medium-sized tree, generally
+associated with _Picea nigra_ and occurs scattered throughout the
+northern pineries. Heartwood reddish; sapwood lighter color,
+straight-grained, compact structure. Wood light, soft, not strong,
+elastic, resonant, not durable when exposed. Used for flooring,
+carpentry, shipbuilding, piles, posts, railway ties, paddles, oars,
+sounding boards, paper pulp, and musical instruments. Montana to
+Pacific, British America.
+
+
+                            BASTARD SPRUCE
+
+Spruce or fir in name, but resembling hard pine or larch in
+appearance, quality and uses of its wood.
+
+=40. Douglas Spruce= (_Pseudotsuga douglasii_) (Yellow Fir, Red Fir,
+Oregon Pine). One of the most important trees of the western United
+States; grows very large in the Pacific States, to fair size in all
+parts of the mountains, in Colorado up to about 10,000 feet above sea
+level; forms extensive forests, often of pure growth, it is really
+neither a pine nor a fir. Wood very variable, usually coarse-grained
+and heavy, with very pronounced summer-wood. Hard and strong ("red"
+fir), but often fine-grained and light ("yellow" fir). It is the chief
+tree of Washington and Oregon, and most abundant and most valuable in
+British Columbia, where it attains its greatest size. From the plains
+to the Pacific Ocean, and from Mexico to British Columbia.
+
+=41. Red Fir= (_Pseudotsuga taxifolia_) (Oregon Pine, Puget Sound Pine,
+Yellow Fir, Douglas Spruce, Red Pine). Heartwood light red or yellow
+in color, sapwood narrow, nearly white, comparatively free from
+resins, variable annual rings. Wood usually hard, strong, difficult to
+work, durable, splinters easily. Used for heavy construction,
+dimension timber, railway ties, doors, blinds, interior finish, piles,
+etc. One of the most important of Western trees. From the plains to
+the Pacific Ocean, and from Mexico to British America.
+
+
+                         TAMARACK (See Larch)
+
+
+                                  YEW
+
+Wood heavy, hard, extremely stiff and strong, of fine texture with a
+pale yellow sapwood, and an orange-red heartwood; seasons well and is
+quite durable. Extensively used for archery bows, turner's ware, etc.
+The yews form no forests, but occur scattered with other conifers.
+
+=42. Yew= (_Taxus brevifolia_). A small to medium-sized tree of the
+Pacific region.
+
+
+
+
+                              SECTION III
+
+                          BROAD-LEAVED TREES
+
+                      WOOD OF BROAD-LEAVED TREES
+
+
+    [Illustration: Fig. 4. Block of Oak. CS, cross-section; RS,
+    radial section; TS, tangential section; _mr_, medullary or
+    pith ray; _a_, height; _b_, width; and _e_, length of pith
+    ray.]
+
+    [Illustration: Fig. 5. Board of Oak. CS, cross-section; RS,
+    radial section; TS, tangential section; _v_, vessels or
+    pores, cut through.; A, slight curve in log which appears in
+    section as an islet.]
+
+    [Illustration: Fig. 6. Cross-section of Oak (Magnified about
+    5 times).]
+
+On a cross-section of oak, the same arrangement of pith and bark, of
+sapwood and heartwood, and the same disposition of the wood in
+well-defined concentric or annual rings occur, but the rings are
+marked by lines or rows of conspicuous pores or openings, which occupy
+the greater part of the spring-wood for each ring (see Fig. 4, also
+6), and are, in fact the hollows of vessels through which the cut has
+been made. On the radial section or quarter-sawn board the several
+layers appear as so many stripes (see Fig. 5); on the tangential
+section or "bastard" face patterns similar to those mentioned for pine
+wood are observed. But while the patterns in hard pine are marked by
+the darker summer-wood, and are composed of plain, alternating stripes
+of darker and lighter wood, the figures in oak (and other broad-leaved
+woods) are due chiefly to the vessels, those of the spring-wood in oak
+being the most conspicuous (see Fig. 5). So that in an oak table, the
+darker, shaded parts are the spring-wood, the lighter unicolored parts
+the summer-wood. On closer examination of the smooth cross-section of
+oak, the spring-wood part of the ring is found to be formed in great
+part of pores; large, round, or oval openings made by the cut through
+long vessels. These are separated by a grayish and quite porous
+tissue (see Fig. 6, A), which continues here and there in the form of
+radial, often branched, patches (not the pith rays) into and through
+the summer-wood to the spring-wood of the next ring. The large vessels
+of the spring-wood, occupying six to ten per cent of the volume of a
+log in very good oak, and twenty-five per cent or more in inferior and
+narrow-ringed timber, are a very important feature, since it is
+evident that the greater their share in the volume, the lighter and
+weaker the wood. They are smallest near the pith, and grow wider
+outward. They are wider in the stem than limb, and seem to be of
+indefinite length, forming open channels, in some cases probably as
+long as the tree itself. Scattered through the radiating gray patches
+of porous wood are vessels similar to those of the spring-wood, but
+decidedly smaller. These vessels are usually fewer and larger near the
+outer portions of the ring. Their number and size can be utilized to
+distinguish the oaks classed as white oaks from those classed as black
+and red oaks. They are fewer and larger in red oaks, smaller but much
+more numerous in white oaks. The summer-wood, except for these radial,
+grayish patches, is dark colored and firm. This firm portion, divided
+into bodies or strands by these patches of porous wood, and also by
+fine, wavy, concentric lines of short, thin-walled cells (see Fig. 6,
+A), consists of thin-walled fibres (see Fig. 7, B), and is the chief
+element of strength in oak wood. In good white oak it forms one-half
+or more of the wood, if it cuts like horn, and the cut surface is
+shiny, and of a deep chocolate brown color. In very narrow-ringed wood
+and in inferior red oak it is usually much reduced in quantity as well
+as quality. The pith rays of the oak, unlike those of the coniferous
+woods, are at least in part very large and conspicuous. (See Fig. 4;
+their height indicated by the letter _a_, and their width by the
+letter _b_.) The large medullary rays of oak are often twenty and more
+cells wide, and several hundred cell rows in height, which amount
+commonly to one or more inches. These large rays are conspicuous on
+all sections. They appear as long, sharp, grayish lines on the
+cross-sections; as short, thick lines, tapering at each end, on the
+tangential or "bastard" face, and as broad, shiny bands, "the
+mirrors," on the radial section. In addition to these coarse rays,
+there is also a large number of small pith rays, which can be seen
+only when magnified. On the whole, the pith rays form a much larger
+part of the wood than might be supposed. In specimens of good white
+oak it has been found that they form about sixteen to twenty-five per
+cent of the wood.
+
+    [Illustration: Fig. 7. Portion of the Firm Bodies of Fibres
+    with Two Cells of a Small Pith Ray _mr_ (Highly Magnified).]
+
+    [Illustration: Fig. 8. Isolated Fibres and Cells, _a_, four
+    cells of wood, parenchyma; _b_, two cells from a pith ray;
+    _c_, a single joint or cell of a vessel, the openings _x_
+    leading into its upper and lower neighbors; _d_, tracheid;
+    _e_, wood fibre proper.]
+
+
+                           Minute Structure
+
+    [Illustration: Fig. 9. Cross-section of Basswood (Magnified).
+    _v_, vessels; _mr_, pith rays.]
+
+If a well-smoothed thin disk or cross-section of oak (say
+one-sixteenth inch thick) is held up to the light, it looks very much
+like a sieve, the pores or vessels appearing as clean-cut holes. The
+spring-wood and gray patches are seen to be quite porous, but the firm
+bodies of fibres between them are dense and opaque. Examined with a
+magnifier it will be noticed that there is no such regularity of
+arrangement in straight rows as is conspicuous in pine. On the
+contrary, great irregularity prevails. At the same time, while the
+pores are as large as pin holes, the cells of the denser wood, unlike
+those of pine wood, are too small to be distinguished. Studied with
+the microscope, each vessel is found to be a vertical row of a great
+number of short, wide tubes, joined end to end (see Fig. 8, _c_). The
+porous spring-wood and radial gray tracts are partly composed of
+smaller vessels, but chiefly of tracheids, like those of pine, and of
+shorter cells, the "wood parenchyma," resembling the cells of the
+medullary rays. These latter, as well as the fine concentric lines
+mentioned as occurring in the summer-wood, are composed entirely of
+short tube-like parenchyma cells, with square or oblique ends (see
+Fig. 8, _a_ and _b_). The wood fibres proper, which form the dark,
+firm bodies referred to, are very fine, thread-like cells, one
+twenty-fifth to one-tenth inch long, with a wall commonly so thick
+that scarcely any empty internal space or lumen remains (see Figs. 8,
+_e_, and 7, B). If, instead of oak, a piece of poplar or basswood (see
+Fig. 9) had been used in this study, the structure would have been
+found to be quite different. The same kinds of cell-elements, vessels,
+etc., are, to be sure, present, but their combination and arrangement
+are different, and thus from the great variety of possible
+combinations results the great variety of structure and, in
+consequence, of the qualities which distinguish the wood of
+broad-leaved trees. The sharp distinction of sap wood and heartwood is
+wanting; the rings are not so clearly defined; the vessels of the
+wood are small, very numerous, and rather evenly scattered through the
+wood of the annual rings, so that the distinction of the ring almost
+vanishes and the medullary or pith rays in poplar can be seen, without
+being magnified, only on the radial section.
+
+
+         LIST OF MOST IMPORTANT BROAD-LEAVED TREES (HARDWOODS)
+
+Woods of complex and very variable structure, and therefore differing
+widely in quality, behavior, and consequently in applicability to the
+arts.
+
+
+                               AILANTHUS
+
+=1. Ailanthus= (_Ailanthus glandulosa_). Medium to large-sized tree.
+Wood pale yellow, hard, fine-grained, and satiny. This species
+originally came from China, where it is known as the Tree of "Heaven,"
+was introduced into the United States and planted near Philadelphia
+during the 18th century, and is more ornamental than useful. It is
+used to some extent in cabinet work. Western Pennsylvania and Long
+Island, New York.
+
+
+                                  ASH
+
+Wood heavy, hard, stiff, quite tough, not durable in contact with the
+soil, straight-grained, rough on the split surfaces and coarse in
+texture. The wood shrinks moderately, seasons with little injury,
+stands well, and takes a good polish. In carpentry, ash is used for
+stairways, panels, etc. It is used in shipbuilding, in the
+construction of cars, wagons, etc., in the manufacture of all kinds of
+farm implements, machinery, and especially of all kinds of furniture;
+for cooperage, baskets, oars, tool handles, hoops, etc., etc. The
+trees of the several species of ash are rapid growers, of small to
+medium height with stout trunks. They form no forests, but occur
+scattered in almost all our broad-leaved forests.
+
+=2. White Ash= (_Fraxinus Americana_). Medium-, sometimes large-sized
+tree. Heartwood reddish brown, usually mottled; sapwood lighter color,
+nearly white. Wood heavy, hard, tough, elastic, coarse-grained,
+compact structure. Annual rings clearly marked by large open pores,
+not durable in contact with the soil, is straight-grained, and the
+best material for oars, etc. Used for agricultural implements, tool
+handles, automobile (rim boards), vehicle bodies and parts, baseball
+bats, interior finish, cabinet work, etc., etc. Basin of the Ohio, but
+found from Maine to Minnesota and Texas.
+
+=3. Red Ash= (_Fraxinus pubescens_ var. _Pennsylvanica_). Medium-sized
+tree, a timber very similar to, but smaller than _Fraxinus Americana_.
+Heartwood light brown, sapwood lighter color. Wood heavy, hard,
+strong, and coarse-grained. Ranges from New Brunswick to Florida, and
+westward to Dakota, Nebraska, and Kansas.
+
+=4. Black Ash= (_Fraxinus nigra_ var. _sambucifolia_) (Hoop Ash, Ground
+Ash). Medium-sized tree, very common, is more widely distributed than
+the _Fraxinus Americana_; the wood is not so hard, but is well suited
+for hoops and basketwork. Heartwood dark brown, sapwood light brown or
+white. Wood heavy, rather soft, tough and coarse-grained. Used for
+barrel hoops, basketwork, cabinetwork and interior of houses. Maine to
+Minnesota and southward to Alabama.
+
+=5. Blue Ash= (_Fraxinus quadrangulata_). Small to medium-sized tree.
+Heartwood yellow, streaked with brown, sapwood a lighter color. Wood
+heavy, hard, and coarse-grained. Not common. Indiana and Illinois;
+occurs from Michigan to Minnesota and southward to Alabama.
+
+=6. Green Ash= (_Fraxinus viridis_). Small-sized tree. Occurs from New
+York to the Rocky Mountains, and southward to Florida and Arizona.
+
+=7. Oregon Ash= (_Fraxinus Oregana_). Small to medium-sized tree. Occurs
+from western Washington to California.
+
+=8. Carolina Ash= (_Fraxinus Caroliniana_). Medium-sized tree. Occurs in
+the Carolinas and the coast regions southward.
+
+
+                          ASPEN (See Poplar)
+
+
+                               BASSWOOD
+
+=9. Basswood= (_Tilia Americana_) (Linden, Lime Tree, American Linden,
+Lin, Bee Tree). Medium- to large-sized tree. Wood light, soft, stiff,
+but not strong, of fine texture, straight and close-grained, and white
+to light brown color, but not durable in contact with the soil. The
+wood shrinks considerably in drying, works well and stands well in
+interior work. It is used for cooperage, in carpentry, in the
+manufacture of furniture and woodenware (both turned and carved), for
+toys, also for panelling of car and carriage bodies, for agricultural
+implements, automobiles, sides and backs of drawers, cigar boxes,
+excelsior, refrigerators, trunks, and paper pulp. It is also largely
+cut for veneer and used as "three-ply" for boxes and chair seats. It
+is used for sounding boards in pianos and organs. If well seasoned and
+painted it stands fairly well for outside work. Common in all northern
+broad-leaved forests. Found throughout the eastern United States, but
+reaches its greatest size in the Valley of the Ohio, becoming often
+130 feet in height, but its usual height is about 70 feet.
+
+=10. White Basswood= (_Tilia heterophylla_) (Whitewood). A small-sized
+tree. Wood in its quality and uses similar to the preceding, only it
+is lighter in color. Most abundant in the Alleghany region.
+
+=11. White Basswood= (_Tilia pubescens_) (Downy Linden, Small-leaved
+Basswood). Small-sized tree. Wood in its quality and uses similar to
+_Tilia Americana_. This is a Southern species which makes it way as
+far north as Long Island. Is found at its best in South Carolina.
+
+
+                                 BEECH
+
+=12. Beech= (_Fagus ferruginea_) (Red Beech, White Beech). Medium-sized
+tree, common, sometimes forming forests of pure growth. Wood heavy,
+hard, stiff, strong, of rather coarse texture, white to light brown
+color, not durable in contact with the soil, and subject to the
+inroads of boring insects. Rather close-grained, conspicuous medullary
+rays, and when quarter-sawn and well smoothed is very beautiful. The
+wood shrinks and checks considerably in drying, works well and stands
+well, and takes a fine polish. Beech is comparatively free from
+objectionable taste, and finds a place in the manufacture of
+commodities which come in contact with foodstuffs, such as lard tubs,
+butter boxes and pails, and the beaters of ice cream freezers; for the
+latter the persistent hardness of the wood when subjected to attrition
+and abrasion, while wet gives it peculiar fitness. It is an excellent
+material for churns. Sugar hogsheads are made of beech, partly because
+it is a tasteless wood and partly because it has great strength. A
+large class of woodenware, including veneer plates, dishes, boxes,
+paddles, scoops, spoons, and beaters, which belong to the kitchen and
+pantry, are made of this species of wood. Beech picnic plates are made
+by the million, a single machine turning out 75,000 a day. The wood
+has a long list of miscellaneous uses and enters in a great variety of
+commodities. In every region where it grows in commercial quantities
+it is made into boxes, baskets, and crating. Beech baskets are chiefly
+employed in shipping fruit, berries, and vegetables. In Maine thin
+veneer of beech is made specially for the Sicily orange and lemon
+trade. This is shipped in bulk and the boxes are made abroad. Beech is
+also an important handle wood, although not in the same class with
+hickory. It is not selected because of toughness and resiliency, as
+hickory is, and generally goes into plane, handsaw, pail, chisel, and
+flatiron handles. Recent statistics show that in the production of
+slack cooperage staves, only two woods, red gum and pine, stood above
+beech in quantity, while for heading, pine alone exceeded it. It is
+also used in turnery, for shoe lasts, butcher blocks, ladder rounds,
+etc. Abroad it is very extensively used by the carpenter, millwright,
+and wagon maker, in turnery and wood carving. Most abundant in the
+Ohio and Mississippi basin, but found from Maine to Wisconsin and
+southward to Florida.
+
+
+                                 BIRCH
+
+=13. Cherry Birch= (_Betula lenta_) (Black Birch, Sweet Birch, Mahogany
+Birch, Wintergreen Birch). Medium-sized tree, very common. Wood of
+beautiful reddish or yellowish brown, and much of it nicely figured,
+of compact structure, is straight in grain, heavy, hard, strong, takes
+a fine polish, and considerably used as imitation of mahogany. The
+wood shrinks considerably in drying, works well and stands well, but
+is not durable in contact with the soil. The medullary rays in birch
+are very fine and close and not easily seen. The sweet birch is very
+handsome, with satiny luster, equalling cherry, and is too costly a
+wood to be profitably used for ordinary purposes, but there are both
+high and low grades of birch, the latter consisting chiefly of sapwood
+and pieces too knotty for first class commodities. This cheap material
+swells the supply of box lumber, and a little of it is found wherever
+birch passes through sawmills. The frequent objections against sweet
+birch as box lumber and crating material are that it is hard to nail
+and is inclined to split. It is also used for veneer picnic plates and
+butter dishes, although it is not as popular for this class of
+commodity as are yellow and paper birch, maple and beech. The best
+grades are largely used for furniture and cabinet work, and also for
+interior finish. Maine to Michigan and to Tennessee.
+
+=14. White Birch= (_Betula populifolia_) (Gray Birch, Old Field Birch,
+Aspen-leaved Birch). Small to medium-sized tree, least common of all
+the birches. Short-lived, twenty to thirty feet high, grows very
+rapidly. Heartwood light brown, sapwood lighter color. Wood light,
+soft, close-grained, not strong, checks badly in drying, decays
+quickly, not durable in contact with the soil, takes a good polish.
+Used for spools, shoepegs, wood pulp, and barrel hoops. Fuel, value
+not high, but burns with bright flame. Ranges from Nova Scotia and
+lower St. Lawrence River, southward, mostly in the coast region to
+Delaware, and westward through northern New England and New York to
+southern shore of Lake Ontario.
+
+=15. Yellow Birch= (_Betula lutea_) (Gray Birch, Silver Birch). Medium-
+to large-sized tree, very common. Heartwood light reddish brown,
+sapwood nearly white, close-grained, compact structure, with a satiny
+luster. Wood heavy, very strong, hard, tough, susceptible of high
+polish, not durable when exposed. Is similar to _Betula lenta_, and
+finds a place in practically all kinds of woodenware. A large
+percentage of broom handles on the market are made of this species of
+wood, though nearly every other birch contributes something. It is
+used for veneer plates and dishes made for pies, butter, lard, and
+many other commodities. Tubs and pails are sometimes made of yellow
+birch provided weight is not objectionable. The wood is twice as heavy
+as some of the pines and cedars. Many small handles for such articles
+as flatirons, gimlets, augers, screw drivers, chisels, varnish and
+paint brushes, butcher and carving knives, etc. It is also widely used
+for shipping boxes, baskets, and crates, and it is one of the
+stiffest, strongest woods procurable, but on account of its excessive
+weight it is sometimes discriminated against. It is excellent for
+veneer boxes, and that is probably one of the most important places it
+fills. Citrus fruit from northern Africa and the islands and countries
+of the Mediterranean is often shipped to market in boxes made of
+yellow birch from veneer cut in New England. The better grades are
+also used for furniture and cabinet work, and the "burls" found on
+this species are highly valued for making fancy articles, gavels, etc.
+It is extensively used for turnery, buttons, spools, bobbins, wheel
+hubs, etc. Maine to Minnesota and southward to Tennessee.
+
+=16. Red Birch= (_Betula rubra_ var. _nigra_) (River Birch). Small to
+medium-sized tree, very common. Lighter and less valuable than the
+preceding. Heartwood light brown, sapwood pale. Wood light, fairly
+strong and close-grained. Red birch is best developed in the middle
+South, and usually grows near the banks of rivers. Its bark hangs in
+tatters, even worse than that of paper birch, but it is darker. In
+Tennessee the slack coopers have found that red birch makes excellent
+barrel heads and it is sometimes employed in preference to other
+woods. In eastern Maryland the manufacturers of peach baskets draw
+their supplies from this wood, and substitute it for white elm in
+making the hoops or bands which stiffen the top of the basket, and
+provide a fastening for the veneer which forms the sides. Red birch
+bends in a very satisfactory manner, which is an important point. This
+wood enters pretty generally into the manufacture of woodenware within
+its range, but statistics do not mention it by name. It is also used
+in the manufacture of veneer picnic plates, pie plates, butter dishes,
+washboards, small handles, kitchen and pantry utensils, and ironing
+boards. New England to Texas and Missouri.
+
+=17. Canoe Birch= (_Betula paprifera_) (White Birch, Paper Birch). Small
+to medium-sized tree, sometimes forming forests, very common.
+Heartwood light brown tinged with red, sapwood lighter color. Wood of
+good quality, but light, fairly hard and strong, tough, close-grained.
+Sap flows freely in spring and by boiling can be made into syrup. Not
+as valuable as any of the preceding. Canoe birch is a northern tree,
+easily identified by its white trunk and its ragged bark. Large
+numbers of small wooden boxes are made by boring out blocks of this
+wood, shaping them in lathes, and fitting lids on them. Canoe birch is
+one of the best woods for this class of commodities, because it can be
+worked very thin, does not split readily, and is of pleasing color.
+Such boxes, or two-piece diminutive kegs, are used as containers for
+articles shipped and sold in small bulk, such as tacks, small nails,
+and brads. Such containers are generally cylindrical and of
+considerably greater depth than diameter. Many others of nearly
+similar form are made to contain ink bottles, bottles of perfumery,
+drugs, liquids, salves, lotions, and powders of many kinds. Many boxes
+of this pattern are used by manufacturers of pencils and crayons for
+packing and shipping their wares. Such boxes are made in numerous
+numbers by automatic machinery. A single machine of the most improved
+pattern will turn out 1,400 boxes an hour. After the boring and
+turning are done, they are smoothed by placing them into a tumbling
+barrel with soapstone. It is also used for one-piece shallow trays or
+boxes, without lids, and used as card receivers, pin receptacles,
+butter boxes, fruit platters, and contribution plates in churches. It
+is also the principal wood used for spools, bobbins, bowls, shoe
+lasts, pegs, and turnery, and is also much used in the furniture
+trade. All along the northern boundary of the United States and
+northward, from the Atlantic to the Pacific.
+
+
+                       BLACK WALNUT (See Walnut)
+
+
+                              BLUE BEECH
+
+=18. Blue Beech= (_Carpinus Caroliniana_) (Hornbeam, Water Beech,
+Ironwood). Small-sized tree. Heartwood light brown, sapwood nearly
+white. Wood very hard, heavy, strong, very stiff, of rather fine
+texture, not durable in contact with the soil, shrinks and checks
+considerably in drying, but works well and stands well, and takes a
+fine polish. Used chiefly in turnery, for tool handles, etc. Abroad
+much used by mill-and wheelwrights. A small tree, largest in the
+Southwest, but found in nearly all parts of the eastern United States.
+
+
+                     BOIS D'ARC (See Osage Orange)
+
+
+                                BUCKEYE
+
+Wood light, soft, not strong, often quite tough, of fine, uniform
+texture and creamy white color. It shrinks considerably in drying, but
+works well and stands well. Used for woodenware, artificial limbs,
+paper pulp, and locally also for building construction.
+
+=19. Ohio Buckeye= (_AEsculus glabra_) (Horse Chestnut, Fetid Buckeye).
+Small-sized tree, scattered, never forming forests. Heartwood white,
+sapwood pale brown. Wood light, soft, not strong, often quite tough
+and close-grained. Alleghanies, Pennsylvania to Oklahoma.
+
+=20. Sweet Buckeye= (_AEsculus octandra_ var. _flava_) (Horse Chestnut).
+Small-sized tree, scattered, never forming forests. Wood in its
+quality and uses similar to the preceding. Alleghanies, Pennsylvania
+to Texas.
+
+
+                              BUCKTHORNE
+
+=21. Buckthorne= (_Rhanmus Caroliniana_) (Indian Cherry). Small-sized
+tree. Heartwood light brown, sapwood almost white. Wood light, hard,
+close-grained. Does not enter the markets to any great extent. Found
+along the borders of streams in rich bottom lands. Its northern limits
+is Long Island, where it is only a shrub; it becomes a tree only in
+southern Arkansas and adjoining regions.
+
+
+                               BUTTERNUT
+
+=22. Butternut= (_Juglans cinerea_) (White Walnut, White Mahogany,
+Walnut). Medium-sized tree, scattered, never forming forests. Wood
+very similar to black walnut, but light, quite soft, and not strong.
+Heartwood light gray-brown, darkening with exposure; sapwood nearly
+white, coarse-grained, compact structure, easily worked, and
+susceptible to high polish. Has similar grain to black walnut and when
+stained is a very good imitation. Is much used for inside work, and
+very durable. Used chiefly for finishing lumber, cabinet work, boat
+finish and fixtures, and for furniture. Butternut furniture is often
+sold as circassian walnut. Largest and most common in the Ohio basin.
+Maine to Minnesota and southward to Georgia and Alabama.
+
+
+                                CATALPA
+
+The catalpa is a tree which was planted about 25 years ago as a
+commercial speculation in Iowa, Kansas, and Nebraska. Its native
+habitat was along the rivers Ohio and lower Wabash, and a century ago
+it gained a reputation for rapid growth and durability, but did not
+grow in large quantities. As a railway tie, experiments have left no
+doubt as to its resistance to decay; it stands abrasion as well as the
+white oak (_Quercus alba_), and is superior to it in longevity.
+Catalpa is a tree singularly free from destructive diseases. Wood cut
+from the living tree is one of the most durable timbers known. In
+spite of its light porous structure it resists the weathering
+influences and the attacks of wood-destroying fungi to a remarkable
+degree. No fungus has yet been found which will grow in the dead
+timber, and for fence posts this wood has no equal, lasting longer
+than almost any other species of timber. The wood is rather soft and
+coarse in texture, the tree is of slow growth, and the brown colored
+heartwood, even of very young trees, forms nearly three-quarters of
+their volume. There is only about one-quarter inch of sapwood in a
+9-inch tree.
+
+=23. Catalpa= (_Catalpa speciosa_ var. _bignonioides_) (Indian Bean).
+Medium-sized tree. Heartwood light brown, sapwood nearly white. Wood
+light, soft, not strong, brittle, very durable in contact with the
+soil, of coarse texture. Used chiefly for railway ties, telegraph
+poles, and fence posts, but well suited for a great variety of uses.
+Lower basin of the Ohio River, locally common. Extensively planted,
+and therefore promising to become of some importance.
+
+
+                                CHERRY
+
+=24. Cherry= (_Prunus serotina_) (Wild Cherry, Black Cherry, Rum
+Cherry). Wood heavy, hard, strong, of fine texture. Sapwood yellowish
+white, heartwood reddish to brown. The wood shrinks considerably in
+drying, works well and stands well, has a fine satin-like luster, and
+takes a fine polish which somewhat resembles mahogany, and is much
+esteemed for its beauty. Cherry is chiefly used as a decorative
+interior finishing lumber, for buildings, cars and boats, also for
+furniture and in turnery, for musical instruments, walking sticks,
+last blocks, and woodenware. It is becoming too costly for many
+purposes for which it is naturally well suited. The lumber-furnishing
+cherry of the United States, the wild black cherry, is a small to
+medium-sized tree, scattered through many of the broad-leaved trees of
+the western slope of the Alleghanies, but found from Michigan to
+Florida, and west to Texas. Other species of this genus, as well as
+the hawthornes (_Prunus cratoegus_) and wild apple (_Pyrus_), are not
+commonly offered in the markets. Their wood is of the same character
+as cherry, often finer, but in smaller dimensions.
+
+=25. Red Cherry= (_Prunus Pennsylvanica_) (Wild Red Cherry, Bird
+Cherry). Small-sized tree. Heartwood light brown, sapwood pale yellow.
+Wood light, soft, and close-grained. Uses similiar to the preceding,
+common throughout the Northern States, reaching its greatest size on
+the mountains of Tennessee.
+
+
+                               CHESTNUT
+
+The chestnut is a long-lived tree, attaining an age of from 400 to 600
+years, but trees over 100 years are usually hollow. It grows quickly,
+and sprouts from a chestnut stump (Coppice Chestnut) often attain a
+height of 8 feet in the first year. It has a fairly cylindrical stem,
+and often grows to a height of 100 feet and over. Coppice chestnut,
+that is, chestnut grown on an old stump, furnishes better timber for
+working than chestnut grown from the nut, it is heavier, less spongy,
+straighter in grain, easier to split, and stands exposure longer.
+
+=26. Chestnut= (_Castanea vulgaris_ var. _Americana_). Medium-to
+large-sized tree, never forming forests. Wood is light, moderately
+hard, stiff, elastic, not strong, but very durable when in contact
+with the soil, of coarse texture. Sapwood light, heartwood darker
+brown, and is readily distinguishable from the sapwood, which very
+early turns into heartwood. It shrinks and checks considerably in
+drying, works easily, stands well. The annual rings are very distinct,
+medullary rays very minute and not visible to the naked eye. Used in
+cooperage, for cabinetwork, agricultural implements, railway ties,
+telegraph poles, fence posts, sills, boxes, crates, coffins,
+furniture, fixtures, foundation for veneer, and locally in heavy
+construction. Very common in the Alleghanies. Occurs from Maine to
+Michigan and southward to Alabama.
+
+=27. Chestnut= (_Castanea dentata_ var. _vesca_). Medium-sized tree,
+never forming forests, not common. Heartwood brown color, sapwood
+lighter shade, coarse-grained. Wood and uses similar to the preceding.
+Occurs scattered along the St. Lawrence River, and even there is met
+with only in small quantities.
+
+=28. Chinquapin= (_Castanea pumila_). Medium- to small-sized tree, with
+wood slightly heavier, but otherwise similiar to the preceding. Most
+common in Arkansas, but with nearly the same range as _Castanea
+vulgaris_.
+
+=29. Chinquapin= (_Castanea chrysophylla_). A medium-sized tree of the
+western ranges of California and Oregon.
+
+
+                              COFFEE TREE
+
+=30. Coffee Tree= (_Gymnocladus dioicus_) (Coffee Nut, Stump Tree). A
+medium- to large-sized tree, not common. Wood heavy, hard, strong,
+very stiff, of coarse texture, and durable. Sapwood yellow, heartwood
+reddish brown, shrinks and checks considerably in drying, works well
+and stands well, and takes a fine polish. It is used to a limited
+extent in cabinetwork and interior finish. Pennsylvania to Minnesota
+and Arkansas.
+
+
+                        COTTONWOOD (See Poplar)
+
+
+                              CRAB APPLE
+
+=31. Crab Apple= (_Pyrus coronaria_) (Wild Apple, Fragrant Crab).
+Small-sized tree. Heartwood reddish brown, sapwood yellow. Wood heavy,
+hard, not strong, close-grained. Used principally for tool handles and
+small domestic articles. Most abundant in the middle and western
+states, reaches its greatest size in the valleys of the lower Ohio
+basin.
+
+
+                     CUCUMBER TREE (See Magnolia)
+
+
+                                DOGWOOD
+
+=32. Dogwood= (_Cornus florida_) (American Box). Small to medium-sized
+tree. Attains a height of about 30 feet and about 12 inches in
+diameter. The heartwood is a red or pinkish color, the sapwood, which
+is considerable, is a creamy white. The wood has a dull surface and
+very fine grain. It is valuable for turnery, tool handles, and
+mallets, and being so free from silex, watchmakers use small splinters
+of it for cleaning out the pivot holes of watches, and opticians for
+removing dust from deep-seated lenses. It is also used for butchers'
+skewers, and shuttle blocks and wheel stock, and is suitable for
+turnery and inlaid work. Occurs scattered in all the broad-leaved
+forests of our country; very common.
+
+
+                                  ELM
+
+Wood heavy, hard, strong, elastic, very tough, moderately durable in
+contact with the soil, commonly cross-grained, difficult to split and
+shape, warps and checks considerably in drying, but stands well if
+properly seasoned. The broad sapwood whitish, heartwood light brown,
+both with shades of gray and red. On split surfaces rough, texture
+coarse to fine, capable of high polish. Elm for years has been the
+principal wood used in slack cooperage for barrel staves, also in the
+construction of cars, wagons, etc., in boat building, agricultural
+implements and machinery, in saddlery and harness work, and
+particularly in the manufacture of all kinds of furniture, where the
+beautiful figures, especially those of the tangential or bastard
+section, are just beginning to be appreciated. The elms are medium- to
+large-sized trees, of fairly rapid growth, with stout trunks; they
+form no forests of pure growth, but are found scattered in all the
+broad-leaved woods of our country, sometimes forming a considerable
+portion of the arborescent growth.
+
+=33. White Elm= (_Ulmus Americana_) (American Elm, Water Elm). Medium-
+to large-sized tree. Wood in its quality and uses as stated above.
+Common. Maine to Minnesota, southward to Florida and Texas.
+
+=34. Rock Elm= (_Ulmus racemosa_) (Cork Elm, Hickory Elm, White Elm,
+Cliff Elm). Medium- to large-sized tree of rapid growth. Heartwood
+light brown, often tinged with red, sapwood yellowish or greenish
+white, compact structure, fibres interlaced. Wood heavy, hard, very
+tough, strong, elastic, difficult to split, takes a fine polish. Used
+for agricultural implements, automobiles, crating, boxes, cooperage,
+tool handles, wheel stock, bridge timbers, sills, interior finish,
+and maul heads. Fairly free from knots and has only a small quantity
+of sapwood. Michigan, Ohio, from Vermont to Iowa, and southward to
+Kentucky.
+
+=35. Red Elm= (_Ulmus fulva_ var. _pubescens_) (Slippery Elm, Moose
+Elm). The red or slippery elm is not as large a tree as the white elm
+(_Ulmus Americana_), though it occasionally attains a height of 135
+feet and a diameter of 4 feet. It grows tall and straight, and thrives
+in river valleys. The wood is heavy, hard, strong, tough, elastic,
+commonly cross-grained, moderately durable in contact with the soil,
+splits easily when green, works fairly well, and stands well if
+properly handled. Careful seasoning and handling are essential for the
+best results. Trees can be utilized for posts when very small. When
+green the wood rots very quickly in contact with the soil. Poles for
+posts should be cut in summer and peeled and dried before setting. The
+wood becomes very tough and pliable when steamed, and is of value for
+sleigh runners and for ribs of canoes and skiffs. Together with white
+elm (_Ulmus Americana_) it is extensively used for barrel staves in
+slack cooperage and also for furniture. The thick, viscous inner bark,
+which gives the tree its descriptive name, is quite palatable,
+slightly nutritious, and has a medicinal value. Found chiefly along
+water courses. New York to Minnesota, and southward to Florida and
+Texas.
+
+=36. Cedar Elm= (_Ulmus crassifolia_). Medium- to small-sized tree,
+locally quite common. Arkansas and Texas.
+
+=37. Winged Elm= (_Ulmus alata_) (Wahoo). Small-sized tree, locally
+quite common. Heartwood light brown, sapwood yellowish white. Wood
+heavy, hard, tough, strong, and close-grained. Arkansas, Missouri, and
+eastern Virginia.
+
+    [Illustration: Fig. 10. A Large Red Gum.]
+
+
+                                  GUM
+
+This general term applies to three important species of gum in the
+South, the principal one usually being distinguished as "red" or
+"sweet" gum (see Fig. 10). The next in importance being the "tupelo"
+or "bay poplar," and the least of the trio is designated as "black" or
+"sour" gum (see Fig. 11). Up to the year 1900 little was known of gum
+as a wood for cooperage purposes, but by the continued advance in
+price of the woods used, a few of the most progressive manufacturers,
+looking into the future, saw that the supply of the various woods in
+use was limited, that new woods would have to be sought, and gum was
+looked upon as a possible substitute, owing to its cheapness and
+abundant supply. No doubt in the future this wood will be used to a
+considerable extent in the manufacture of both "tight" and "slack"
+cooperage. In the manufacture of the gum, unless the knives and saws
+are kept very sharp, the wood has a tendency to break out, the corners
+splitting off; and also, much difficulty has been experienced in
+seasoning and kiln-drying.
+
+    [Illustration: Fig. 11. A Tupelo Gum Slough.]
+
+In the past, gum, having no marketable value, has been left standing
+after logging operations, or, where the land has been cleared for
+farming, the trees have been "girdled" and allowed to rot, and then
+felled and burned as trash. Now, however, that there is a market for
+this species of timber, it will be profitable to cut the gum with the
+other hardwoods, and this species of wood will come in for a greater
+share of attention than ever before.
+
+=38. Red Gum= (_Liquidamber styraciflua_) (Sweet Gum, Hazel Pine, Satin
+Walnut, Liquidamber, Bilsted). The wood is about as stiff and as
+strong as chestnut, rather heavy, it splits easily and is quite brash,
+commonly cross-grained, of fine texture, and has a large proportion of
+whitish sapwood, which decays rapidly when exposed to the weather; but
+the reddish brown heartwood is quite durable, even in the ground. The
+external appearance of the wood is of fine grain and smooth, close
+texture, but when broken the lines of fracture do not run with
+apparent direction of the growth; possibly it is this unevenness of
+grain which renders the wood so difficult to dry without twisting and
+warping. It has little resiliency; can be easily bent when steamed,
+and when properly dried will hold its shape. The annual rings are not
+distinctly marked, medullary rays fine and numerous. The green wood
+contains much water, and consequently is heavy and difficult to float,
+but when dry it is as light as basswood. The great amount of water in
+the green wood, particularly in the sap, makes it difficult to season
+by ordinary methods without warping and twisting. It does not check
+badly, is tasteless and odorless, and when once seasoned, swells and
+shrinks but little unless exposed to the weather. Used for boat
+finish, veneers, cabinet work, furniture, fixtures, interior
+decoration, shingles, paving blocks, woodenware, cooperage, machinery
+frames, refrigerators, and trunk slats.
+
+
+                           Range of Red Gum
+
+Red gum is distributed from Fairfield County, Conn., to southeastern
+Missouri, through Arkansas and Oklahoma to the valley of the Trinity
+River in Texas, and eastward to the Atlantic coast. Its commercial
+range is restricted, however, to the moist lands of the lower Ohio and
+Mississippi basins and of the Southeastern coast. It is one of the
+commonest timber trees in the hardwood bottoms and drier swamps of the
+South. It grows in mixture with ash, cottonwood and oak (see Fig. 12).
+It is also found to a considerable extent on the lower ridges and
+slopes of the southern Appalachians, but there it does not reach
+merchantable value and is of little importance. Considerable
+difference is found between the growth in the upper Mississippi
+bottoms and that along the rivers on the Atlantic coast and on the
+Gulf. In the latter regions the bottoms are lower, and consequently
+more subject to floods and to continued overflows (see Fig. 11). The
+alluvial deposit is also greater, and the trees grow considerably
+faster. Trees of the same diameter show a larger percentage of sapwood
+there than in the upper portions of the Mississippi Valley. The
+Mississippi Valley hardwood trees are for the most part considerably
+older, and reach larger dimensions than the timber along the coast.
+
+
+                          Form of the Red Gum
+
+In the best situations red gum reaches a height of 150 feet, and a
+diameter of 5 feet. These dimensions, however are unusual. The stem is
+straight and cylindrical, with dark, deeply-furrowed bark, and
+branches often winged with corky ridges. In youth, while growing
+vigorously under normal conditions, it assumes a long, regular,
+conical crown, much resembling the form of a conifer (see Fig. 12).
+After the tree has attained its height growth, however, the crown
+becomes rounded, spreading and rather ovate in shape. When growing in
+the forest the tree prunes itself readily at an early period, and
+forms a good length of clear stem, but it branches strongly after
+making most of its height growth. The mature tree is usually forked,
+and the place where the forking commences determines the number of
+logs in the tree or its merchantable length, by preventing cutting to
+a small diameter in the top. On large trees the stem is often not less
+than eighteen inches in diameter where the branching begins. The
+over-mature tree is usually broken and dry topped, with a very
+spreading crown, in consequence of new branches being sent out.
+
+
+                         Tolerance of Red Gum
+
+Throughout its entire life red gum is intolerant in shade, there are
+practically no red seedlings under the dense forest cover of the
+bottom land, and while a good many may come up under the pine forest
+on the drier uplands, they seldom develop into large trees. As a rule
+seedlings appear only in clearings or in open spots in the forest. It
+is seldom that an over-topped tree is found, for the gum dies quickly
+if suppressed, and is consequently nearly always a dominant or
+intermediate tree. In a hardwood bottom forest the timber trees are
+all of nearly the same age over considerable areas, and there is
+little young growth to be found in the older stands. The reason for
+this is the intolerance of most of the swamp species. A scale of
+intolerance containing the important species, and beginning with the
+most light-demanding, would run as follows: Cottonwood, sycamore, red
+gum, white elm, white ash, and red maple.
+
+
+                    Demands upon Soil and Moisture
+
+While the red gum grows in various situations, it prefers the deep,
+rich soil of the hardwood bottoms, and there reaches its best
+development (see Fig. 10). It requires considerable soil moisture,
+though it does not grow in the wetter swamps, and does not thrive on
+dry pine land. Seedlings, however, are often found in large numbers on
+the edges of the uplands and even on the sandy pine land, but they
+seldom live beyond the pole stage. When they do, they form small,
+scrubby trees that are of little value. Where the soil is dry the tree
+has a long tap root. In the swamps, where the roots can obtain water
+easily, the development of the tap root is poor, and it is only
+moderate on the glade bottom lands, where there is considerable
+moisture throughout the year, but no standing water in the summer
+months.
+
+
+                        Reproduction of Red Gum
+
+    [Illustration: Fig. 12. Second Growth Red Gum, Ash,
+    Cottonwood, and Sycamore.]
+
+Red gum reproduces both by seed and by sprouts (see Fig. 12). It
+produces seed fairly abundantly every year, but about once in three
+years there is an extremely heavy production. The tree begins to bear
+seed when twenty-five to thirty years old, and seeds vigorously up to
+an age of one hundred and fifty years, when its productive power
+begins to diminish. A great part of the seed, however, is abortive.
+Red gum is not fastidious in regard to its germinating bed; it comes
+up readily on sod in old fields and meadows, on decomposing humus in
+the forest, or on bare clay-loam or loamy sand soil. It requires a
+considerable degree of light, however, and prefers a moist seed bed.
+The natural distribution of the seed takes place for several hundred
+feet from the seed trees, the dissemination depending almost entirely
+on the wind. A great part of the seed falls on the hardwood bottom
+when the land is flooded, and is either washed away or, if already in
+the ground and germinating, is destroyed by the long-continued
+overflow. After germinating, the red gum seedling demands, above
+everything else, abundant light for its survival and development. It
+is for this reason that there is very little growth of red gum, either
+in the unculled forest or on culled land, where, as is usually the
+case, a dense undergrowth of cane, briers, and rattan is present.
+Under the dense underbrush of cane and briers throughout much of the
+virgin forest, reproduction of any of the merchantable species is of
+course impossible. And even where the land has been logged over, the
+forest is seldom open enough to allow reproduction of cottonwood and
+red gum. Where, however, seed trees are contiguous to pastures or
+cleared land, scattered seedlings are found springing up in the open,
+and where openings occur in the forest, there are often large numbers
+of red gum seedlings, the reproduction generally occurring in groups.
+But over the greater part of the Southern hardwood bottom land forest
+reproduction is very poor. The growth of red gum during the early part
+of its life, and up to the time it reaches a diameter of eight inches
+breast-high, is extremely rapid, and, like most of the intolerant
+species, it attains its height growth at an early period. Gum sprouts
+readily from the stump, and the sprouts surpass the seedlings in rate
+of height growth for the first few years, but they seldom form large
+timber trees. Those over fifty years of age seldom sprout. For this
+reason sprout reproduction is of little importance in the forest. The
+principal requirements of red gum, then, are a moist, fairly rich soil
+and good exposure to light. Without these it will not reach its best
+development.
+
+    [Illustration: Fig. 13. A Cypress Slough in the Dry Season.]
+
+
+                         Second-Growth Red Gum
+
+Second-growth red gum occurs to any considerable extent only on land
+which has been thoroughly cleared. Throughout the South there is a
+great deal of land which was in cultivation before the Civil War, but
+which during the subsequent period of industrial depression was
+abandoned and allowed to revert to forest. These old fields now mostly
+covered with second-growth forest, of which red gum forms an
+important part (see Fig. 12). Frequently over fifty per cent of the
+stand consists of this species, but more often, and especially on the
+Atlantic coast, the greater part is of cottonwood or ash. These stands
+are very dense, and the growth is extremely rapid. Small stands of
+young growth are also often found along the edges of cultivated
+fields. In the Mississippi Valley the abandoned fields on which young
+stands have sprung up are for the most part being rapidly cleared
+again. The second growth here is considered of little value in
+comparison with the value of the land for agricultural purposes. In
+many cases, however, the farm value of the land is not at present
+sufficient to make it profitable to clear it, unless the timber cut
+will at least pay for the operation. There is considerable land upon
+which the second growth will become valuable timber within a few
+years. Such land should not be cleared until it is possible to utilize
+the timber.
+
+=39. Tupelo Gum= (_Nyssa aquatica_) (Bay Poplar, Swamp Poplar, Cotton
+Gum, Hazel Pine, Circassian Walnut, Pepperidge, Nyssa). The close
+similarity which exists between red and tupelo gum, together with the
+fact that tupelo is often cut along with red gum, and marketed with
+the sapwood of the latter, makes it not out of place to give
+consideration to this timber. The wood has a fine, uniform texture, is
+moderately hard and strong, is stiff, not elastic, very tough and hard
+to split, but easy to work with tools. Tupelo takes glue, paint, or
+varnish well, and absorbs very little of the material. In this respect
+it is equal to yellow poplar and superior to cottonwood. The wood is
+not durable in contact with ground, and requires much care in
+seasoning. The distinction between the heartwood and sapwood of this
+species is marked. The former varies in color from a dull gray to a
+dull brown; the latter is whitish or light yellow like that of poplar.
+The wood is of medium weight, about thirty-two pounds per cubic foot
+when dry, or nearly that of red gum and loblolly pine. After
+seasoning it is difficult to distinguish the better grades of sapwood
+from poplar. Owing to the prejudice against tupelo gum, it was until
+recently marketed under such names as bay poplar, swamp poplar, nyssa,
+cotton gum, circassian walnut, and hazel pine. Since it has become
+evident that the properties of the wood fit it for many uses, the
+demand for tupelo has largely increased, and it is now taking rank
+with other standard woods under its rightful name. Heretofore the
+quality and usefulness of this wood were greatly underestimated, and
+the difficulty of handling it was magnified. Poor success in seasoning
+and kiln-drying was laid to defects of the wood itself, when, as a
+matter of fact, the failures were largely due to the absence of proper
+methods in handling. The passing of this prejudice against tupelo is
+due to a better understanding of the characteristics and uses of the
+wood. Handled in the way in which its particular character demands,
+tupelo is a wood of much value.
+
+
+                          Uses of Tupelo Gum
+
+Tupelo gum is now used in slack cooperage, principally for heading. It
+is used extensively for house flooring and inside finishing, such as
+mouldings, door jambs, and casings. A great deal is now shipped to
+European countries, where it is highly valued for different classes of
+manufacture. Much of the wood is used in the manufacture of boxes,
+since it works well upon rotary veneer machines. There is also an
+increasing demand for tupelo for laths, wooden pumps, violin and organ
+sounding boards, coffins, mantelwork, conduits and novelties. It is
+also used in the furniture trade for backing, drawers, and panels.
+
+
+                          Range of Tupelo Gum
+
+Tupelo occurs throughout the coastal region of the Atlantic States,
+from southern Virginia to northern Florida, through the Gulf States to
+the valley of the Nueces River in Texas, through Arkansas and southern
+Missouri to western Kentucky and Tennessee, and to the valley of the
+lower Wabash River. Tupelo is being extensively milled at present only
+in the region adjacent to Mobile Ala., and in southern and central
+Louisiana, where it occurs in large merchantable quantities, attaining
+its best development in the former locality. The country in this
+locality is very swampy (see Fig. 11), and within a radius of one
+hundred miles tupelo gum is one of the principal timber trees. It
+grows only in the swamps and wetter situations (see Fig. 11), often in
+mixture with cypress, and in the rainy season it stands in from two to
+twenty feet of water.
+
+=40. Black Gum= (_Nyssa sylvatica_) (Sour Gum). Black gum is not cut to
+much extent, owing to its less abundant supply and poorer quality, but
+is used for repair work on wagons, for boxes, crates, wagon hubs,
+rollers, bowls, woodenware, and for cattle yokes and other purposes
+which require a strong, non-splitting wood. Heartwood is light brown
+in color, often nearly white; sapwood hardly distinguishable, fine
+grain, fibres interwoven. Wood is heavy, not hard, difficult to work,
+strong, very tough, checks and warps considerably in drying, not
+durable. It is distributed from Maine to southern Ontario, through
+central Michigan to southeastern Missouri, southward to the valley of
+the Brazos River in Texas, and eastward to the Kissimmee River and
+Tampa Bay in Florida. It is found in the swamps and hardwood bottoms,
+but is more abundant and of better size on the slightly higher ridges
+and hummocks in these swamps, and on the mountain slopes in the
+southern Alleghany region. Though its range is greater than that of
+either red or tupelo gum, it nowhere forms an important part of the
+forest.
+
+
+                               HACKBERRY
+
+=41. Hackberry= (_Celtis occidentalis_) (Sugar Berry, Nettle Tree). The
+wood is handsome, heavy, hard, strong, quite tough, of moderately fine
+texture, and greenish or yellowish color, shrinks moderately, works
+well and stands well, and takes a good polish. Used to some extent in
+cooperage, and in the manufacture of cheap furniture. Medium- to
+large-sized tree, locally quite common, largest in the lower
+Mississippi Valley. Occurs in nearly all parts of the eastern United
+States.
+
+
+                                HICKORY
+
+The hickories of commerce are exclusively North American and some of
+them are large and beautiful trees of 60 to 70 feet or more in height.
+They are closely allied to the walnut, and the wood is very like
+walnut in grain and color, though of a somewhat darker brown. It is
+one of the finest of American hardwoods in point of strength; in
+toughness it is superior to ash, rather coarse in texture, smooth and
+of straight grain, very heavy and strong as well as elastic and
+tenacious, but decays rapidly, especially the sapwood when exposed to
+damp and moisture, and is very liable to attack from worms and boring
+insects. The cross-section of hickory is peculiar, the annual rings
+appear like fine lines instead of like the usual pores, and the
+medullary rays, which are also very fine but distinct, in crossing
+these form a peculiar web-like pattern which is one of the
+characteristic differences between hickory and ash. Hickory is rarely
+subjected to artificial treatment, but there is this curious fact in
+connection with the wood, that, contrary to most other woods, creosote
+is only with difficulty injected into the sap, although there is no
+difficulty in getting it into the heartwood. It dries slowly, shrinks
+and checks considerably in seasoning; is not durable in contact with
+the soil or if exposed. Hickory excels as wagon and carriage stock,
+for hoops in cooperage, and is extensively used in the manufacture of
+implements and machinery, for tool handles, timber pins, harness work,
+dowel pins, golf clubs, and fishing rods. The hickories are tall trees
+with slender stems, never forming forests, occasionally small groves,
+but usually occur scattered among other broad-leaved trees in suitable
+localities. The following species all contribute more or less to the
+hickory of the markets:
+
+=42. Shagbark Hickory= (_Hicoria ovata_) (Shellbark Hickory, Scalybark
+Hickory). A medium- to large-sized tree, quite common; the favorite
+among the hickories. Heartwood light brown, sapwood ivory or
+cream-colored. Wood close-grained, compact structure, annual rings
+clearly marked. Very hard, heavy, strong, tough, and flexible, but not
+durable in contact with the soil or when exposed. Used for
+agricultural implements, wheel runners, tool handles, vehicle parts,
+baskets, dowel pins, harness work, golf clubs, fishing rods, etc. Best
+developed in the Ohio and Mississippi basins; from Lake Ontario to
+Texas, Minnesota to Florida.
+
+=43. Mockernut Hickory= (_Hicoria alba_) (Black Nut Hickory, Black
+Hickory, Bull Nut Hickory, Big Bud Hickory, White Heart Hickory). A
+medium- to large-sized tree. Wood in its quality and uses similar to
+the preceding. Its range is the same as that of _Hicoria ovata_.
+Common, especially in the South.
+
+=44. Pignut Hickory= (_Hicoria glabra_) (Brown Hickory, Black Hickory,
+Switchbud Hickory). A medium- to large-sized tree. Heavier and
+stronger than any of the preceding. Heartwood light to dark brown,
+sapwood nearly white. Abundant, all eastern United States.
+
+=45. Bitternut Hickory= (_Hicoria minima_) (Swamp Hickory). A
+medium-sized tree, favoring wet localities. Heartwood light brown,
+sapwood lighter color. Wood in its quality and uses not so valuable as
+_Hicoria ovata_, but is used for the same purposes. Abundant, all
+eastern United States.
+
+=46. Pecan= (_Hicoria pecan_) (Illinois Nut). A large tree, very common
+in the fertile bottoms of the western streams. Indiana to Nebraska and
+southward to Louisiana and Texas.
+
+
+                                 HOLLY
+
+=47. Holly= (_Ilex opaca_). Small to medium-sized tree. Wood of medium
+weight, hard, strong, tough, of exceedingly fine grain, closer in
+texture than most woods, of white color, sometimes almost as white as
+ivory; requires great care in its treatment to preserve the whiteness
+of the wood. It does not readily absorb foreign matter. Much used by
+turners and for all parts of musical instruments, for handles on whips
+and fancy articles, draught-boards, engraving blocks, cabinet work,
+etc. The wood is often dyed black and sold as ebony; works well and
+stands well. Most abundant in the lower Mississippi Valley and Gulf
+States, but occurring eastward to Massachusetts and north to Indiana.
+
+=48. Holly= (_Ilex monticolo_) (Mountain Holly). Small-sized tree. Wood
+in its quality and uses similar to the preceding, but is not very
+generally known. It is found in the Catskill Mountains and extends
+southward along the Alleghanies as far as Alabama.
+
+
+                     HORSE CHESTNUT (See Buckeye)
+
+
+                               IRONWOOD
+
+=49. Ironwood= (_Ostrya Virginiana_) (Hop Hornbeam, Lever Wood).
+Small-sized tree, common. Heartwood light brown tinged with red,
+sapwood nearly white. Wood heavy, tough, exceedingly close-grained,
+very strong and hard, durable in contact with the soil, and will take
+a fine polish. Used for small articles like levers, handles of tools,
+mallets, etc. Ranges throughout the United States east of the Rocky
+Mountains.
+
+
+                                LAUREL
+
+=50. Laurel= (_Umbellularia Californica_) (Myrtle). A Western tree,
+produces timber of light brown color of great size and beauty, and is
+very valuable for cabinet and inside work, as it takes a fine polish.
+California and Oregon, coast range of the Sierra Nevada Mountains.
+
+
+                                LOCUST
+
+=51. Black Locust= (_Robinia pseudacacia_) (Locust, Yellow Locust,
+Acacia). Small to medium-sized tree. Wood very heavy, hard, strong,
+and tough, rivalling some of the best oak in this latter quality. The
+wood has great torsional strength, excelling most of the soft woods in
+this respect, of coarse texture, close-grained and compact structure,
+takes a fine polish. Annual rings clearly marked, very durable in
+contact with the soil, shrinks and checks considerably in drying, the
+very narrow sapwood greenish yellow, the heartwood brown, with shades
+of red and green. Used for wagon hubs, trenails or pins, but
+especially for railway ties, fence posts, and door sills. Also used
+for boat parts, turnery, ornamentations, and locally for construction.
+Abroad it is much used for furniture and farming implements and also
+in turnery. At home in the Alleghany Mountains, extensively planted,
+especially in the West.
+
+=52. Honey Locust= (_Gleditschia triacanthos_) (Honey Shucks, Locust,
+Black Locust, Brown Locust, Sweet Locust, False Acacia, Three-Thorned
+Acacia). A medium-sized tree. Wood heavy, hard, strong, tough, durable
+in contact with the soil, of coarse texture, susceptible to a good
+polish. The narrow sapwood yellow, the heartwood brownish red. So far,
+but little appreciated except for fences and fuel. Used to some extent
+for wheel hubs, and locally in rough construction. Found from
+Pennsylvania to Nebraska, and southward to Florida and Texas; locally
+quite abundant.
+
+=53. Locust= (_Robinia viscosa_) (Clammy Locust). Usually a shrub five
+or six feet high, but known to reach a height of 40 feet in the
+mountains of North Carolina, with the habit of a tree. Wood light
+brown, heavy, hard, and close-grained. Not used to much extent in
+manufacture. Range same as the preceding.
+
+
+                               MAGNOLIA
+
+=54. Magnolia= (_Magnolia glauca_) (Swamp Magnolia, Small Magnolia,
+Sweet Bay, Beaver Wood). Small-sized tree. Heartwood reddish brown,
+sap wood cream white. Sparingly used in manufacture. Ranges from Essex
+County, Mass., to Long Island, N. Y., from New Jersey to Florida, and
+west in the Gulf region to Texas.
+
+=55. Magnolia= (_Magnolia tripetala_) (Umbrella Tree). A small-sized
+tree. Wood in its quality similiar to the preceding. It may be easily
+recognized by its great leaves, twelve to eighteen inches long, and
+five to eight inches broad. This species as well as the preceding is
+an ornamental tree. Ranges from Pennsylvania southward to the Gulf.
+
+=56. Cucumber Tree= (_Magnolia accuminata_) (Tulip-wood, Poplar).
+Medium- to large-sized tree. Heartwood yellowish brown, sapwood almost
+white. Wood light, soft, satiny, close-grained, durable in contact
+with the soil, resembling and sometimes confounded with tulip tree
+(_Liriodendron tulipifera_) in the markets. The wood shrinks
+considerably, but seasons without much injury, and works and stands
+well. It bends readily when steamed, and takes stain and paint well.
+Used in cooperage, for siding, for panelling and finishing lumber in
+house, car and shipbuilding, etc., also in the manufacture of toys,
+culinary woodenware, and backing for drawers. Most common in the
+southern Alleghanies, but distributed from western New York to
+southern Illinois, south through central Kentucky and Tennessee to
+Alabama, and throughout Arkansas.
+
+
+                                 MAPLE
+
+Wood heavy, hard, strong, stiff, and tough, of fine texture,
+frequently wavy-grained, this giving rise to "curly" and "blister"
+figures which are much admired. Not durable in the ground, or when
+exposed. Maple is creamy white, with shades of light brown in the
+heartwood, shrinks moderately, seasons, works, and stands well, wears
+smoothly, and takes a fine polish. The wood is used in cooperage, and
+for ceiling, flooring, panelling, stairway, and other finishing lumber
+in house, ship, and car construction. It is used for the keels of
+boats and ships, in the manufacture of implements and machinery, but
+especially for furniture, where entire chamber sets of maple rival
+those of oak. Maple is also used for shoe lasts and other form blocks;
+for shoe pegs; for piano actions, school apparatus, for wood type in
+show bill printing, tool handles, in wood carving, turnery, and scroll
+work, in fact it is one of our most useful woods. The maples are
+medium-sized trees, of fairly rapid growth, sometimes form forests,
+and frequently constitute a large proportion of the arborescent
+growth. They grow freely in parts of the Northern Hemisphere, and are
+particularly luxuriant in Canada and the northern portions of the
+United States.
+
+=57. Sugar Maple= (_Acer saccharum_) (Hard Maple, Rock Maple). Medium-
+to large-sized tree, very common, forms considerable forests, and is
+especially esteemed. The wood is close-grained, heavy, fairly hard and
+strong, of compact structure. Heartwood brownish, sapwood lighter
+color; it can be worked to a satin-like surface and take a fine
+polish, it is not durable if exposed, and requires a good deal of
+seasoning. Medullary rays small but distinct. The "curly" or "wavy"
+varieties furnish wood of much beauty, the peculiar contortions of the
+grain called "bird's eye" being much sought after, and used as veneer
+for panelling, etc. It is used in all good grades of furniture,
+cabinetmaking, panelling, interior finish, and turnery; it is not
+liable to warp and twist. It is also largely used for flooring, for
+rollers for wringers and mangling machines, for which there is a large
+and increasing demand. The peculiarity known as "bird's eye," and
+which causes a difficulty in working the wood smooth, owing to the
+little pieces like knots lifting up, is supposed to be due to the
+action of boring insects. Its resistance to compression across the
+grain is higher than that of most other woods. Ranges from Maine to
+Minnesota, abundant, with birch, in the region of the Great Lakes.
+
+=58. Red Maple= (_Acer rubrum_) (Swamp Maple, Soft Maple, Water Maple).
+Medium-sized tree. Like the preceding but not so valuable. Scattered
+along water-courses and other moist localities. Abundant. Maine to
+Minnesota, southward to northern Florida.
+
+=59. Silver Maple= (_Acer saccharinum_) (Soft Maple, White Maple,
+Silver-Leaved Maple). Medium- to large-sized tree, common. Wood
+lighter, softer, and inferior to _Acer saccharum_, and usually offered
+in small quantities and held separate in the markets. Heartwood
+reddish brown, sapwood ivory white, fine-grained, compact structure.
+Fibres sometimes twisted, weaved, or curly. Not durable. Used in
+cooperage for woodenware, turnery articles, interior decorations and
+flooring. Valley of the Ohio, but occurs from Maine to Dakota and
+southward to Florida.
+
+=60. Broad-Leaved Maple= (_Acer macrophyllum_) (Oregon Maple).
+Medium-sized tree, forms considerable forests, and, like the preceding
+has a lighter, softer, and less valuable wood than _Acer saccharum_.
+Pacific Coast regions.
+
+=61. Mountain Maple= (_Acer spicatum_). Small-sized tree. Heartwood pale
+reddish brown, sapwood lighter color. Wood light, soft, close-grained,
+and susceptible of high polish. Ranges from lower St. Lawrence River
+to northern Minnesota and regions of the Saskatchewan River; south
+through the Northern States and along the Appalachian Mountains to
+Georgia.
+
+=62. Ash-Leaved Maple= (_Acer negundo_) (Box Elder). Medium- to
+large-sized tree. Heartwood creamy white, sapwood nearly white. Wood
+light, soft, close-grained, not strong. Used for woodenware and paper
+pulp. Distributed across the continent, abundant throughout the
+Mississippi Valley along banks of streams and borders of swamps.
+
+=63. Striped Maple= (_Acer Pennsylvanicum_) (Moose-wood). Small-sized
+tree. Produces a very white wood much sought after for inlaid and for
+cabinet work. Wood is light, soft, close-grained, and takes a fine
+polish. Not common. Occurs from Pennsylvania to Minnesota.
+
+
+                               MULBERRY
+
+=64. Red Mulberry= (_Morus rubra_). A small-sized tree. Wood moderately
+heavy, fairly hard and strong, rather tough, of coarse texture, very
+durable in contact with the soil. The sapwood whitish, heartwood
+yellow to orange brown, shrinks and checks considerably in drying,
+works well and stands well. Used in cooperage and locally in
+construction, and in the manufacture of farm implements. Common in the
+Ohio and Mississippi Valleys, but widely distributed in the eastern
+United States.
+
+
+                          MYRTLE (See Laurel)
+
+
+                                  OAK
+
+Wood very variable, usually very heavy and hard, very strong and
+tough, porous, and of coarse texture. The sapwood whitish, the
+heartwood "oak" to reddish brown. It shrinks and checks badly, giving
+trouble in seasoning, but stands well, is durable, and little subject
+to the attacks of boring insects. Oak is used for many purposes, and
+is the chief wood used for tight cooperage; it is used in
+shipbuilding, for heavy construction, in carpentry, in furniture, car
+and wagon work, turnery, and even in woodcarving. It is also used in
+all kinds of farm implements, mill machinery, for piles and wharves,
+railway ties, etc., etc. The oaks are medium- to large-sized trees,
+forming the predominant part of a large proportion of our
+broad-leaved forests, so that these are generally termed "oak
+forests," though they always contain considerable proportion of other
+kinds of trees. Three well-marked kinds--white, red, and live oak--are
+distinguished and kept separate in the markets. Of the two principal
+kinds "white oak" is the stronger, tougher, less porous, and more
+durable. "Red oak" is usually of coarser texture, more porous, often
+brittle, less durable, and even more troublesome in seasoning than
+white oak. In carpentry and furniture work red oak brings the same
+price at present as white oak. The red oaks everywhere accompany the
+white oaks, and, like the latter, are usually represented by several
+species in any given locality. "Live oak," once largely employed in
+shipbuilding, possesses all the good qualities, except that of size,
+of white oak, even to a greater degree. It is one of the heaviest,
+hardest, toughest, and most durable woods of this country. In
+structure it resembles the red oak, but is less porous.
+
+=65. White Oak= (_Quercus alba_) (American Oak). Medium-to large-sized
+tree. Heartwood light brown, sapwood lighter color. Annual rings well
+marked, medullary rays broad and prominent. Wood tough, strong, heavy,
+hard, liable to check in seasoning, durable in contact with the soil,
+takes a high polish, very elastic, does not shrink much, and can be
+bent to any form when steamed. Used for agricultural implements, tool
+handles, furniture, fixtures, interior finish, car and wagon
+construction, beams, cabinet work, tight cooperage, railway ties,
+etc., etc. Because of the broad medullary rays, it is generally
+"quarter-sawn" for cabinet work and furniture. Common in the Eastern
+States, Ohio and Mississippi Valleys. Occurs throughout the eastern
+United States.
+
+=66. White Oak= (_Quercus durandii_). Medium- to small-sized tree. Wood
+in its quality and uses similiar to the preceding. Texas, eastward to
+Alabama.
+
+=67. White Oak= (_Quercus garryana_) (Western White Oak). Medium- to
+large-sized tree. Stronger, more durable, and wood more compact than
+_Quercus alba_. Washington to California.
+
+=68. White Oak= (_Quercus lobata_). Medium- to large-sized tree. Largest
+oak on the Pacific Coast. Wood in its quality and uses similar to
+_Quercus alba_, only it is finer-grained. California.
+
+=69. Bur Oak= (_Quercus macrocarpa_) (Mossy-Cup Oak, Over-Cup Oak).
+Large-sized tree. Heartwood "oak" brown, sapwood lighter color. Wood
+heavy, strong, close-grained, durable in contact with the soil. Used
+in ship- and boatbuilding, all sorts of construction, interior finish
+of houses, cabinet work, tight cooperage, carriage and wagon work,
+agricultural implements, railway ties, etc., etc. One of the most
+valuable and most widely distributed of American oaks, 60 to 80 feet
+in height, and, unlike most of the other oaks, adapts itself to
+varying climatic conditions. It is one of the most durable woods when
+in contact with the soil. Common, locally abundant. Ranges from
+Manitoba to Texas, and from the foot hills of the Rocky Mountains to
+the Atlantic Coast. It is the most abundant oak of Kansas and
+Nebraska, and forms the scattered forests known as "The oak openings"
+of Minnesota.
+
+=70. Willow Oak= (_Quercus phellos_) (Peach oak). Small to medium-sized
+tree. Heartwood pale reddish brown, sapwood lighter color. Wood heavy,
+hard, strong, coarse-grained. Occasionally used in construction. New
+York to Texas, and northward to Kentucky.
+
+=71. Swamp White Oak= (_Quercus bicolor_ var. _platanoides_).
+Large-sized tree. Heartwood pale brown, sapwood the same color. Wood
+heavy, hard, strong, tough, coarse-grained, checks considerably in
+seasoning. Used in construction, interior finish of houses,
+carriage-and boatbuilding, agricultural implements, in cooperage,
+railway ties, fencing, etc., etc. Ranges from Quebec to Georgia and
+westward to Arkansas. Never abundant. Most abundant in the Lake
+States.
+
+=72. Over-Cup Oak= (_Quercus lyrata_) (Swamp White Oak, Swamp Post Oak).
+Medium to large-sized tree, rather restricted, as it grows in the
+swampy districts of Carolina and Georgia. Is a larger tree than most
+of the other oaks, and produces an excellent timber, but grows in
+districts difficult of access, and is not much used. Lower Mississippi
+and eastward to Delaware.
+
+=73. Pin Oak= (_Quercus palustris_) (Swamp Spanish Oak, Water Oak).
+Medium- to large-sized tree. Heartwood pale brown with dark-colored
+sap wood. Wood heavy, strong, and coarse-grained. Common along the
+borders of streams and swamps, attains its greatest size in the valley
+of the Ohio. Arkansas to Wisconsin, and eastward to the Alleghanies.
+
+=74. Water Oak= (_Quercus aquatica_) (Duck Oak, Possum Oak). Medium- to
+large-sized tree, of extremely rapid growth. Eastern Gulf States,
+eastward to Delaware and northward to Missouri and Kentucky.
+
+=75. Chestnut Oak= (_Quercus prinus_) (Yellow Oak, Rock Oak, Rock
+Chestnut Oak). Heartwood dark brown, sapwood lighter color. Wood
+heavy, hard, strong, tough, close-grained, durable in contact with the
+soil. Used for railway ties, fencing, fuel, and locally for
+construction. Ranges from Maine to Georgia and Alabama, westward
+through Ohio, and southward to Kentucky and Tennessee.
+
+=76. Yellow Oak= (_Quercus acuminata_) (Chestnut Oak, Chinquapin Oak).
+Medium- to large-sized tree. Heartwood dark brown, sapwood pale brown.
+Wood heavy, hard, strong, close-grained, durable in contact with the
+soil. Used in the manufacture of wheel stock, in cooperage, for
+railway ties, fencing, etc., etc. Ranges from New York to Nebraska and
+eastern Kansas, southward in the Atlantic region to the District of
+Columbia, and west of the Alleghanies southward to the Gulf States.
+
+=77. Chinquapin Oak= (_Quercus prinoides_) (Dwarf Chinquapin Oak, Scrub
+Chestnut Oak). Small-sized tree. Heartwood light brown, sapwood darker
+color. Does not enter the markets to any great extent. Ranges from
+Massachusetts to North Carolina, westward to Missouri, Nebraska,
+Kansas, and eastern Texas. Reaches its best form in Missouri and
+Kansas.
+
+=78. Basket Oak= (_Quercus michauxii_) (Cow Oak). Large-sized tree.
+Locally abundant. Lower Mississippi and eastward to Delaware.
+
+=79. Scrub Oak= (_Quercus ilicifolia_ var. _pumila_) (Bear Oak).
+Small-sized tree. Heartwood light brown, sapwood darker color. Wood
+heavy, hard, strong, and coarse-grained. Found in New England and
+along the Alleghanies.
+
+=80. Post Oak= (_Quercus obtusiloda_ var. _minor_) (Iron Oak). Medium-
+to large-sized tree, gives timber of great strength. The color is of a
+brownish yellow hue, close-grained, and often superior to the white
+oak (_Quercus alba_) in strength and durability. It is used for posts
+and fencing, and locally for construction. Arkansas to Texas, eastward
+to New England and northward to Michigan.
+
+=81. Red Oak= (_Quercus rubra_) (Black Oak). Medium- to large-sized
+tree. Heartwood light brown to red, sapwood lighter color. Wood
+coarse-grained, well-marked annual rings, medullary rays few but
+broad. Wood heavy, hard, strong, liable to check in seasoning. It is
+found over the same range as white oak, and is more plentiful. Wood is
+spongy in grain, moderately durable, but unfit for work requiring
+strength. Used for agricultural implements, furniture, bob sleds,
+vehicle parts, boxes, cooperage, woodenware, fixtures, interior
+finish, railway ties, etc., etc. Common in all parts of its range.
+Maine to Minnesota, and southward to the Gulf.
+
+=82. Black Oak= (_Quercus tinctoria_ var. _velutina_) (Yellow Oak).
+Medium- to large-sized tree. Heartwood bright brown tinged with red,
+sapwood lighter color. Wood heavy, hard, strong, coarse-grained,
+checks considerably in seasoning. Very common in the Southern States,
+but occurring North as far as Minnesota, and eastward to Maine.
+
+=83. Barren Oak= (_Quercus nigra_ var. _marilandica_) (Black Jack, Jack
+Oak). Small-sized tree. Heartwood dark brown, sapwood lighter color.
+Wood heavy, hard, strong, coarse-grained, not valuable. Used in the
+manufacture of charcoal and for fuel. New York to Kansas and Nebraska,
+and southward to Florida. Rare in the North, but abundant in the
+South.
+
+=84. Shingle Oak= (_Quercus imbricaria_) (Laurel Oak). Small to
+medium-sized tree. Heartwood pale reddish brown, sapwood lighter
+color. Wood heavy, hard, strong, coarse-grained, checks considerably
+in drying. Used for shingles and locally for construction. Rare in the
+east, most abundant in the lower Ohio Valley. From New York to
+Illinois and southward. Reaches its greatest size in southern Illinois
+and Indiana.
+
+=85. Spanish Oak= (_Quercus digitata_ var. _falcata_) (Red Oak).
+Medium-sized tree. Heartwood light reddish brown, sapwood much
+lighter. Wood heavy, hard, strong, coarse-grained, and checks
+considerably in seasoning. Used locally for construction, and has high
+fuel value. Common in south Atlantic and Gulf region, but found from
+Texas to New York, and northward to Missouri and Kentucky.
+
+=86. Scarlet Oak= (_Quercus coccinea_). Medium- to large-sized tree.
+Heartwood light reddish-brown, sapwood darker color. Wood heavy, hard,
+strong, and coarse-grained. Best developed in the lower basin of the
+Ohio, but found from Minnesota to Florida.
+
+=87. Live Oak= (_Quercus virens_) (Maul Oak). Medium- to large-sized
+tree. Grows from Maryland to the Gulf of Mexico, and often attains a
+height of 60 feet and 4 feet in diameter. The wood is hard, strong,
+and durable, but of rather rapid growth, therefore not as good quality
+as _Quercus alba_. The live oak of Florida is now reserved by the
+United States Government for Naval purposes. Used for mauls and
+mallets, tool handles, etc., and locally for construction. Scattered
+along the coast from Maryland to Texas.
+
+=88. Live Oak= (_Quercus chrysolepis_) (Maul Oak, Valparaiso Oak).
+Medium- to small-sized tree. California.
+
+
+                             OSAGE ORANGE
+
+=89. Osage Orange= (_Maclura aurantiaca_) (Bois d'Arc). A small-sized
+tree of fairly rapid growth. Wood very heavy, exceedingly hard,
+strong, not tough, of moderately coarse texture, and very durable and
+elastic. Sapwood yellow, heartwood brown on the end face, yellow on
+the longitudinal faces, soon turning grayish brown if exposed. It
+shrinks considerably in drying, but once dry it stands unusually well.
+Much used for wheel stock, and wagon framing; it is easily split, so
+is unfit for wheel hubs, but is very suitable for wheel spokes. It is
+considered one of the timbers likely to supply the place of black
+locust for insulator pins on telegraph poles. Seems too little
+appreciated; it is well suited for turned ware and especially for
+woodcarving. Used for spokes, insulator pins, posts, railway ties,
+wagon framing, turnery, and woodcarving. Scattered through the rich
+bottoms of Arkansas and Texas.
+
+
+                                 PAPAW
+
+=90. Papaw= (_Asimina triloba_) (Custard Apple). Small-sized tree, often
+only a shrub, Heartwood pale, yellowish green, sapwood lighter color.
+Wood light, soft, coarse-grained, and spongy. Not used to any extent
+in manufacture. Occurs in eastern and central Pennsylvania, west as
+far as Michigan and Kansas, and south to Florida and Texas. Often
+forming dense thickets in the lowlands bordering the Mississippi
+River.
+
+
+                               PERSIMMON
+
+=91. Persimmon= (_Diospyros Virginiana_). Small to medium-sized tree.
+Wood very heavy, and hard, strong and tough; resembles hickory, but is
+of finer texture and elastic, but liable to split in working. The
+broad sapwood cream color, the heartwood brown, sometimes almost
+black. The persimmon is the Virginia date plum, a tree of 30 to 50
+feet high, and 18 to 20 inches in diameter; it is noted chiefly for
+its fruit, but it produces a wood of considerable value. Used in
+turnery, for wood engraving, shuttles, bobbins, plane stock, shoe lasts,
+and largely as a substitute for box (_Buxus sempervirens_)--especially
+the black or Mexican variety,--also used for pocket rules and drawing
+scales, for flutes and other wind instruments. Common, and best
+developed in the lower Ohio Valley, but occurs from New York to Texas
+and Missouri.
+
+
+                     POPLAR (See also Tulip Wood)
+
+Wood light, very soft, not strong, of fine texture, and whitish,
+grayish to yellowish color, usually with a satiny luster. The wood
+shrinks moderately (some cross-grained forms warp excessively), but
+checks very little in seasoning; is easily worked, but is not durable.
+Used in cooperage, for building and furniture lumber, for crates and
+boxes (especially cracker boxes), for woodenware, and paper pulp.
+
+=92. Cottonwood= (_Populus monilifera_, var. _angulata_) (Carolina
+Poplar). Large-sized tree, forms considerable forests along many of
+the Western streams, and furnishes most of the cottonwood of the
+market. Heartwood dark brown, sapwood nearly white. Wood light, soft,
+not strong, and close-grained (see Fig. 14). Mississippi Valley and
+West. New England to the Rocky Mountains.
+
+=93. Cottonwood= (_Populus fremontii_ var. _wislizeni_). Medium-to
+large-sized tree. Common. Wood in its quality and uses similiar to the
+preceding, but not so valuable. Texas to California.
+
+    [Illustration: Fig. 14. A Large Cottonwood. One of the
+    Associates of Red Gum.]
+
+=94. Black Cottonwood= (_Populus trichocarpa_ var. _heterophylla_)
+(Swamp Cottonwood, Downy Poplar). The largest deciduous tree of
+Washington. Very common. Heartwood dull brown, sapwood lighter brown.
+Wood soft, close-grained. Is now manufactured into lumber in the West
+and South, and used in interior finish of buildings. Northern Rocky
+Mountains and Pacific region.
+
+=95. Poplar= (_Populus grandidentata_) (Large-Toothed Aspen).
+Medium-sized tree. Heartwood light brown, sapwood nearly white. Wood
+soft and close-grained, neither strong nor durable. Chiefly used for
+wood pulp. Maine to Minnesota and southward along the Alleghanies.
+
+=96. White Poplar= (_Populus alba_) (Abele-Tree). Small to medium-sized
+tree. Wood in its quality and uses similar to the preceding. Found
+principally along banks of streams, never forming forests. Widely
+distributed in the United States.
+
+=97. Lombardy Poplar= (_Populus nigra italica_). Medium-to large-sized
+tree. This species is the first ornamental tree introduced into the
+United States, and originated in Afghanistan. Does not enter into the
+markets. Widely planted in the United States.
+
+=98. Balsam= (_Populus balsamifera_) (Balm of Gilead, Tacmahac). Medium-
+to large-sized tree. Heartwood light brown, sapwood nearly white. Wood
+light, soft, not strong, close-grained. Used extensively in the
+manufacture of paper pulp. Common all along the northern boundary of
+the United States.
+
+=99. Aspen= (_Populus tremuloides_) (Quaking Aspen). Small to
+medium-sized tree, often forming extensive forests, and covering
+burned areas. Heartwood light brown, sapwood nearly white. Wood light,
+soft, close-grained, neither strong nor durable. Chiefly used for
+woodenware, cooperage, and paper pulp. Maine to Washington and
+northward, and south in the western mountains to California and New
+Mexico.
+
+
+                           RED GUM (See Gum)
+
+
+                               SASSAFRAS
+
+=100. Sassafras= (_Sassafras sassafras_). Medium-sized tree, largest in
+the lower Mississippi Valley. Wood light, soft, not strong, brittle,
+of coarse texture, durable in contact with the soil. The sapwood
+yellow, the heartwood orange brown. Used to some extent in slack
+cooperage, for skiff- and boatbuilding, fencing, posts, sills, etc.
+Occurs from New England to Texas and from Michigan to Florida.
+
+
+                          SOUR GUM (See Gum)
+
+
+                               SOURWOOD
+
+=101. Sourwood= (_Oxydendrum arboreum_) (Sorrel-Tree). A slender tree,
+reaching the maximum height of 60 feet. Heartwood reddish brown,
+sapwood lighter color. Wood heavy, hard, strong, close-grained, and
+takes a fine polish. Ranges from Pennsylvania, along the Alleghanies,
+to Florida and Alabama, westward through Ohio to southern Indiana and
+southward through Arkansas and Louisiana to the Coast.
+
+
+                          SWEET GUM (See Gum)
+
+
+                               SYCAMORE
+
+=102. Sycamore= (_Platanus occidentalis_) (Buttonwood, Button-Ball Tree,
+Plane Tree, Water Beech). A large-sized tree, of rapid growth. One of
+the largest deciduous trees of the United States, sometimes attaining
+a height of 100 feet. It produces a timber that is moderately heavy,
+quite hard, stiff, strong, and tough, usually cross-grained; of coarse
+texture, difficult to split and work, shrinks moderately, but warps
+and checks considerably in seasoning, but stands well, and is not
+considered durable for outside work, or in contact with the soil. It
+has broad medullary rays, and much of the timber has a beautiful
+figure. It is used in slack cooperage, and quite extensively for
+drawers, backs, and bottoms, etc., in furniture work. It is also used
+for cabinet work, for tobacco boxes, crates, desks, flooring,
+furniture, ox-yokes, butcher blocks, and also for finishing lumber,
+where it has too long been underrated. Common and largest in the Ohio
+and Mississippi Valleys, at home in nearly all parts of the eastern
+United States.
+
+=103. Sycamore= (_Platanus racemosa_). The California species,
+resembling in its wood the Eastern form. Not used to any great extent.
+
+
+                              TULIP TREE
+
+=104. Tulip Tree= (_Liriodendron tulipifera_) (Yellow Poplar, Tulip
+Wood, White Wood, Canary Wood, Poplar, Blue Poplar, White Poplar,
+Hickory Poplar). A medium- to large-sized tree, does not form forests,
+but is quite common, especially in the Ohio basin. Wood usually light,
+but varies in weight, it is soft, tough, but not strong, of fine
+texture, and yellowish color. The wood shrinks considerably, but
+seasons without much injury, and works and stands extremely well.
+Heartwood light yellow or greenish brown, the sapwood is thin, nearly
+white, and decays rapidly. The heartwood is fairly durable when
+exposed to the weather or in contact with the soil. It bends readily
+when steamed, and takes stain and paint well. The mature forest-grown
+tree has a long, straight, cylindrical bole, clear of branches for at
+least two thirds of its length, surmounted by a short, open, irregular
+crown. When growing in the open, the tree maintains a straight stem,
+but the crown extends almost to the ground, and is of conical shape.
+Yellow poplar, or tulip wood, ordinarily grows to a height of from 100
+to 125 feet, with a diameter of from 3 to 6 feet, and a clear length
+of about 70 feet. Trees have been found 190 feet high and ten feet in
+diameter. Used in cooperage, for siding, for panelling and finishing
+lumber in houses, car- and shipbuilding, for sideboards, panels of
+wagons and carriages, for aeroplanes, for automobiles, also in the
+manufacture of furniture farm implements, machinery, for pump logs,
+and almost every kind of common woodenware, boxes shelving, drawers,
+etc., etc. Also in the manufacture of toys, culinary woodenware, and
+backing for veneer. It is in great demand throughout the vehicle and
+implement trade, and also makes a fair grade of wood pulp. In fact the
+tulip tree is one of the most useful of woods throughout the
+woodworking industry of this country. Occurs from New England to
+Missouri and southward to Florida.
+
+
+                           TUPELO (See Gum)
+
+
+                                WAAHOO
+
+=105. Waahoo= (_Evonymus atropurpureus_). (Burning Bush, Spindle Tree).
+A small-sized tree. Wood white, tinged with orange; heavy, hard,
+tough, and close-grained, works well and stands well. Used principally
+for arrows and spindles. Widely distributed. Usually a shrub six to
+ten feet high, becoming a tree only in southern Arkansas and Oklahoma.
+
+
+                                WALNUT
+
+=106. Black Walnut= (_Juglans nigra_) (Walnut). A large, beautiful, and
+quickly-growing tree, about 60 feet and upwards in height. Wood heavy,
+hard, strong, of coarse texture, very durable in contact with the
+soil. The narrow sapwood whitish, the heartwood dark, rich, chocolate
+brown, sometimes almost black; aged trees of fine quality bring fancy
+prices. The wood shrinks moderately in seasoning, works well and
+stands well, and takes a fine polish. It is quite handsome, and has
+been for a long time the favorite wood for cabinet and furniture
+making. It is used for gun-stocks, fixtures, interior decoration,
+veneer, panelling, stair newells, and all classes of work demanding a
+high priced grade of wood. Black walnut is a large tree with stout
+trunk, of rapid growth, and was formerly quite abundant throughout
+the Alleghany region. Occurs from New England to Texas, and from
+Michigan to Florida. Not common.
+
+
+                     WHITE WALNUT (See Butternut)
+
+
+               WHITE WOOD (See Tulip and also Basswood)
+
+
+                             WHITE WILLOW
+
+=107. White Willow= (_Salix alba_ var. _vitellina_) (Willow, Yellow
+Willow, Blue Willow). The wood is very soft, light, flexible, and
+fairly strong, is fairly durable in contact with the soil, works well
+and stands well when seasoned. Medium-sized tree, characterized by a
+short, thick trunk, and a large, rather irregular crown composed of
+many branches. The size of the tree at maturity varies with the
+locality. In the region where it occurs naturally, a height of 70 to
+80 feet, and a diameter of three to four feet are often attained. When
+planted in the Middle West, a height of from 50 to 60 feet, and a
+diameter of one and one-half to two feet are all that may be expected.
+When closely planted on moist soil, the tree forms a tall, slender
+stem, well cleared branches. Is widely naturalized in the United
+States. It is used in cooperage, for woodenware, for cricket and
+baseball bats, for basket work, etc. Charcoal made from the wood is
+used in the manufacture of gunpowder. It has been generally used for
+fence posts on the Northwestern plains, because of scarcity of better
+material. Well seasoned posts will last from four to seven years.
+Widely distributed throughout the United States.
+
+=108. Black Willow= (_Salix nigra_). Small-sized tree. Heartwood light
+reddish brown, sapwood nearly white. Wood soft, light, not strong,
+close-grained, and very flexible. Used in basket making, etc. Ranges
+from New York to Rocky Mountains and southward to Mexico.
+
+=109. Shining Willow= (_Salix lucida_). A small-sized tree. Wood in its
+quality and uses similiar to the preceding. Ranges from Newfoundland
+to Rocky Mountains and southward to Pennsylvania and Nebraska.
+
+=110. Perch Willow= (_Salix amygdaloides_) (Almond-leaf Willow). Small
+to medium-sized tree. Heartwood light brown, sapwood lighter color.
+Wood light, soft, flexible, not strong, close-grained. Uses similiar
+to the preceding. Follows the water courses and ranges across the
+continent; less abundant in New England than elsewhere. Common in the
+West.
+
+=111. Long-Leaf Willow= (_Salix fluviatilis_) (Sand Bar Willow). A
+small-sized tree. Ranges from the Arctic Circle to Northern Mexico.
+
+=112. Bebb Willow= (_Salix bebbiana_ var. _rostrata_). A small-sized
+tree. More abundant in British America than in the United States,
+where it ranges southward to Pennsylvania and westward to Minnesota.
+
+=113. Glaucous Willow= (_Salix discolor_) (Pussy Willow). A small-sized
+tree. Common along the banks of streams, and ranges from Nova Scotia
+to Manitoba, and south to Delaware; west to Indiana and northwestern
+Missouri.
+
+=114. Crack Willow= (_Salix fragilis_). A medium to large-sized tree.
+Wood is very soft, light, very flexible and fairly strong, is fairly
+durable in contact with the soil, works well and stands well. Used
+principally for basket making, hoops, etc., and to produce charcoal
+for gunpowder. Very common, and widely distributed in the United
+States.
+
+=115. Weeping Willow= (_Salix babylonica_). Medium- to large-sized tree.
+Wood similiar to _Salix nigra_, but not so valuable. Mostly an
+ornamental tree. Originally came from China. Widely planted in the
+United States.
+
+
+                              YELLOW WOOD
+
+=116. Yellow Wood= (_Cladrastis lutea_) (Virgilia). A small to
+medium-sized tree. Wood yellow to pale brown, heavy, hard,
+close-grained and strong. Not used to much extent in manufacturing.
+Not common. Found principally on the limestone cliffs of Kentucky,
+Tennessee, and North Carolina.
+
+
+
+
+                              SECTION IV
+
+            GRAIN, COLOR, ODOR, WEIGHT, AND FIGURE IN WOOD
+
+
+                       DIFFERENT GRAINS OF WOOD
+
+The terms "fine-grained," "coarse-grained," "straight-grained," and
+"cross-grained" are frequently applied in the trade. In common usage,
+wood is coarse-grained if its annual rings are wide; fine-grained if
+they are narrow. In the finer wood industries a fine-grained wood is
+capable of high polish, while a coarse-grained wood is not, so that in
+this latter case the distinction depends chiefly on hardness, and in
+the former on an accidental case of slow or rapid growth. Generally if
+the direction of the wood fibres is parallel to the axis of the stem
+or limb in which they occur, the wood is straight-grained; but in many
+cases the course of the fibres is spiral or twisted around the tree
+(as shown in Fig. 15), and sometimes commonly in the butts of gum and
+cypress, the fibres of several layers are oblique in one direction,
+and those of the next series of layers are oblique in the opposite
+direction. (As shown in Fig. 16 the wood is cross or twisted grain.)
+Wavy-grain in a tangential plane as seen on the radial section is
+illustrated in Fig. 17, which represents an extreme case observed in
+beech. This same form also occurs on the radial plane, causing the
+tangential section to appear wavy or in transverse folds.
+
+When wavy grain is fine (_i.e._, the folds or ridges small but
+numerous) it gives rise to the "curly" structure frequently seen in
+maple. Ordinarily, neither wavy, spiral, nor alternate grain is
+visible on the cross-section; its existence often escapes the eye even
+on smooth, longitudinal faces in the sawed material, so that the only
+guide to their discovery lies in splitting the wood in two, in the two
+normal plains.
+
+    [Illustration: Fig. 15. Spiral Grain. Season checks, after
+    removal of bark, indicate the direction of the fibres or
+    grain of the wood.]
+
+    [Illustration: Fig. 16. Alternating Spiral Grain in Cypress.
+    Side and end view of same piece. When the bark was at _o_,
+    the grain of this piece was straight. From that time, each
+    year it grew more oblique in one direction, reaching a climax
+    at _a_, and then turned back in the opposite direction. These
+    alternations were repeated periodically, the bark sharing in
+    these changes.]
+
+Generally the surface of the wood under the bark, and therefore also
+that of any layer in the interior, is not uniform and smooth, but is
+channelled and pitted by numerous depressions, which differ greatly in
+size and form. Usually, any one depression or elevation is restricted
+to one or few annual layers (_i.e._, seen only in one or few rings)
+and is then lost, being compensated (the surface at the particular
+spot evened up) by growth. In some woods, however, any depression or
+elevation once attained grows from year to year and reaches a maximum
+size, which is maintained for many years, sometimes throughout life.
+In maple, where this tendency to preserve any particular contour is
+very great, the depressions and elevations are usually small
+(commonly less than one-eighth inch) but very numerous.
+
+On tangent boards of such wood, the sections, pits, and prominences
+appear as circlets, and give rise to the beautiful "bird's eye" or
+"landscape" structure. Similiar structures in the burls of black ash,
+maple, etc., are frequently due to the presence of dormant buds, which
+cause the surface of all the layers through which they pass to be
+covered by small conical elevations, whose cross-sections on the sawed
+board appear as irregular circlets or islets, each with a dark speck,
+the section of the pith or "trace" of the dormant bud in the center.
+
+    [Illustration: Fig. 17. Wavy Grain in Beech (_after
+    Nordlinger_).]
+
+In the wood of many broad-leaved trees the wood fibres are much longer
+when full grown than when they are first formed in the cambium or
+growing zone. This causes the tips of each fibre to crowd in between
+the fibres above and below, and leads to an irregular interlacement of
+these fibres, which adds to the toughness, but reduces the
+cleavability of the wood. At the juncture of the limb and stem the
+fibres on the upper and lower sides of the limb behave differently.
+On the lower side they run from the stem into the limb, forming an
+uninterrupted strand or tissue and a perfect union. On the upper side
+the fibres bend aside, are not continuous into the limb, and hence the
+connection is not perfect (see Fig. 18). Owing to this arrangement of
+the fibres, the cleft made in splitting never runs into the knot if
+started on the side above the limb, but is apt to enter the knot if
+started below, a fact well understood in woodcraft. When limbs die,
+decay, and break off, the remaining stubs are surrounded, and may
+finally be covered by the growth of the trunk and thus give rise to
+the annoying "dead" or "loose" knots.
+
+    [Illustration: Fig. 18. Section of Wood showing Position of
+    the Grain at Base of a Limb. P, pith of both stem and limb;
+    1-7, seven yearly layers of wood; _a_, _b_, knot or basal
+    part of a limb which lived for four years, then died and
+    broke off near the stem, leaving the part to the left of _a_,
+    _b_, a "sound" knot, the part to the right a "dead" knot,
+    which would soon be entirely covered by the growing stem.]
+
+
+                        COLOR AND ODOR OF WOOD
+
+Color, like structure, lends beauty to the wood, aids in its
+identification, and is of great value in the determination of its
+quality. If we consider only the heartwood, the black color of the
+persimmon, the dark brown of the walnut, the light brown of the white
+oaks, the reddish brown of the red oaks, the yellowish white of the
+tulip and poplars, the brownish red of the redwood and cedars, the
+yellow of the papaw and sumac, are all reliable marks of distinction
+and color. Together with luster and weight, they are only too often
+the only features depended upon in practice. Newly formed wood, like
+that of the outer few rings, has but little color. The sapwood
+generally is light, and the wood of trees which form no heartwood
+changes but little, except when stained by forerunners of disease.
+
+The different tints of colors, whether the brown of oak, the orange
+brown of pine, the blackish tint of walnut, or the reddish cast of
+cedar, are due to pigments, while the deeper shade of the summer-wood
+bands in pine, cedar, oak, or walnut is due to the fact that the wood
+being denser, more of the colored wood substance occurs on a given
+space, _i.e._, there is more colored matter per square inch. Wood is
+translucent, a thin disk of pine permitting light to pass through
+quite freely. This translucency affects the luster and brightness of
+lumber.
+
+When lumber is attacked by fungi, it becomes more opaque, loses its
+brightness, and in practice is designated "dead," in distinction to
+"live" or bright timber. Exposure to air darkens all wood; direct
+sunlight and occasional moistening hasten this change, and cause it to
+penetrate deeper. Prolonged immersion has the same effect, pine wood
+becoming a dark gray, while oak changes to a blackish brown.
+
+Odor, like color, depends on chemical compounds, forming no part of
+the wood substance itself. Exposure to weather reduces and often
+changes the odor, but a piece of long-leaf pine, cedar, or camphor
+wood exhales apparently as much odor as ever when a new surface is
+exposed. Heartwood is more odoriferous than sapwood. Many kinds of
+wood are distinguished by strong and peculiar odors. This is
+especially the case with camphor, cedar, pine, oak, and mahogany, and
+the list would comprise every kind of wood in use were our sense of
+smell developed in keeping with its importance.
+
+Decomposition is usually accompanied by pronounced odors. Decaying
+poplar emits a disagreeable odor, while red oak often becomes
+fragrant, its smell resembling that of heliotrope.
+
+
+                            WEIGHT OF WOOD
+
+A small cross-section of wood (as in Fig. 19) dropped into water
+sinks, showing that the substance of which wood fibre or wood is built
+up is heavier than water. By immersing the wood successively in
+heavier liquids, until we find a liquid in which it does not sink, and
+comparing the weight of the same with water, we find that wood
+substance is about 1.6 times as heavy as water, and that this is as
+true of poplar as of oak or pine.
+
+    [Illustration: Fig. 19. Cross-section of a Group of Wood
+    Fibres (Highly Magnified.)]
+
+Separating a single cell (as shown in Fig. 20, _a_), drying and then
+dropping it into water, it floats. The air-filled cell cavity or
+interior reduces its weight, and, like an empty corked bottle, it
+weighs less than the water. Soon, however, water soaks into the cell,
+when it fills up and sinks. Many such cells grown together, as in a
+block of wood, when all or most of them are filled with water, will
+float as long as the majority of them are empty or only partially
+filled. This is why a green, sappy pine pole soon sinks in "driving"
+(floating down stream). Its cells are largely filled before it is
+thrown in, and but little additional water suffices to make its weight
+greater than that of the water. In a good-sized white pine log,
+composed chiefly of empty cells (heartwood), the water requires a very
+long time to fill up the cells (five years would not suffice to fill
+them all), and therefore the log may float for many months. When the
+wall of the wood fibre is very thick (five eighths or more of the
+volume, as in Fig. 20, _b_), the fibre sinks whether empty or filled.
+This applies to most of the fibres of the dark summer-wood bands in
+pines, and to the compact fibres of oak or hickory, and many,
+especially tropical woods, have such thick-walled cells and so little
+empty or air space that they never float.
+
+    [Illustration: Fig. 20. Isolated Fibres of Wood.]
+
+Here, then, are the two main factors of weight in wood; the amount of
+cell wall or wood substance constant for any given piece, and the
+amount of water contained in the wood, variable even in the standing
+tree, and only in part eliminated in drying.
+
+The weight of the green wood of any species varies chiefly as a second
+factor, and is entirely misleading, if the relative weight of
+different kinds is sought. Thus some green sticks of the otherwise
+lighter cypress and gum sink more readily than fresh oak.
+
+The weight of sapwood or the sappy, peripheral part of our common
+lumber woods is always great, whether cut in winter or summer. It
+rarely falls much below forty-five pounds, and commonly exceeds
+fifty-five pounds to the cubic foot, even in our lighter wooded
+species. It follows that the green wood of a sapling is heavier than
+that of an old tree, the fresh wood from a disk of the upper part of a
+tree is often heavier than that of the lower part, and the wood near
+the bark heavier than that nearer the pith; and also that the
+advantage of drying the wood before shipping is most important in
+sappy and light kinds.
+
+When kiln-dried, the misleading moisture factor of weight is uniformly
+reduced, and a fair comparison possible. For the sake of convenience
+in comparison, the weight of wood is expressed either as the weight
+per cubic foot, or, what is still more convenient, as specific weight
+or density. If an old long-leaf pine is cut up (as shown in Fig. 21)
+the wood of disk No. 1 is heavier than that of disk No. 2, the latter
+heavier than that of disk No. 3, and the wood of the top disk is found
+to be only about three fourths as heavy as that of disk No. 1.
+Similiarly, if disk No. 2 is cut up, as in the figure, the specific
+weight of the different parts is:
+
+              _a_, about 0.52
+              _b_, about 0.64
+              _c_, about 0.67
+    _d_, _e_, _f_, about 0.65
+
+showing that in this disk at least the wood formed during the many
+years' growth, represented in piece _a_, is much lighter than that of
+former years. It also shows that the best wood is the middle part,
+with its large proportion of dark summer bands.
+
+    [Illustration: Fig. 21. Orientation of Wood Samples.]
+
+Cutting up all disks in the same way, it will be found that the piece
+_a_ of the first disk is heavier than the piece _a_ of the fifth, and
+that piece _c_ of the first disk excels the piece _c_ of all the other
+disks. This shows that the wood grown during the same number of years
+is lighter in the upper parts of the stem; and if the disks are
+smoothed on the radial surfaces and set up one on top of the other in
+their regular order, for the sake of comparison, this decrease in
+weight will be seen to be accompanied by a decrease in the amount of
+summer-wood. The color effect of the upper disks is conspicuously
+lighter. If our old pine had been cut one hundred and fifty years ago,
+before the outer, lighter wood was laid on, it is evident that the
+weight of the wood of any one disk would have been found to increase
+from the center outward, and no subsequent decrease could have been
+observed.
+
+In a thrifty young pine, then, the wood is heavier from the center
+outward, and lighter from below upward; only the wood laid on in old
+age falls in weight below the average. The number of brownish bands of
+summer-wood are a direct indication of these differences. If an old
+oak is cut up in the same manner, the butt cut is also found heaviest
+and the top lightest, but, unlike the disk of pine, the disk of oak
+has its firmest wood at the center, and each successive piece from the
+center outward is lighter than its neighbor.
+
+Examining the pieces, this difference is not as readily explained by
+the appearance of each piece as in the case of pine wood.
+Nevertheless, one conspicuous point appears at once. The pores, so
+very distinct in oak, are very minute in the wood near the center, and
+thus the wood is far less porous.
+
+Studying different trees, it is found that in the pines, wood with
+narrow rings is just as heavy as and often heavier than the wood with
+wider rings; but if the rings are unusually narrow in any part of the
+disk, the wood has a lighter color; that is, there is less summer-wood
+and therefore less weight.
+
+In oak, ash, or elm trees of thrifty growth, the rings, fairly wide
+(not less than one-twelfth inch), always form the heaviest wood, while
+any piece with very narrow rings is light. On the other hand, the
+weight of a piece of hard maple or birch is quite independent of the
+width of its rings.
+
+The bases of limbs (knots) are usually heavy, very heavy in conifers,
+and also the wood which surrounds them, but generally the wood of the
+limbs is lighter than that of the stem, and the wood of the roots is
+the lightest.
+
+In general, it may be said that none of the native woods in common use
+in this country are when dry as heavy as water, _i.e._, sixty-two
+pounds to the cubic foot. Few exceed fifty pounds, while most of them
+fall below forty pounds, and much of the pine and other coniferous
+wood weigh less than thirty pounds per cubic foot. The weight of the
+wood is in itself an important quality. Weight assists in
+distinguishing maple from poplar. Lightness coupled with great
+strength and stiffness recommends wood for a thousand different uses.
+To a large extent weight predicates the strength of the wood, at least
+in the same species, so that a heavy piece of oak will exceed in
+strength a light piece of the same species, and in pine it appears
+probable that, weight for weight, the strength of the wood of various
+pines is nearly equal.
+
+WEIGHT OF KILN-DRIED WOOD OF DIFFERENT SPECIES
+-----------------------------------------+----------------------------
+                                         |        Approximate
+                                         |----------+-----------------
+                                         |          |    Weight of
+                                         |          |---------+-------
+           Species                       | Specific |    1    | 1,000
+                                         |  Weight  |  Cubic  |  Feet
+                                         |          |  Foot   | Lumber
+-----------------------------------------+----------+---------+-------
+(_a_) Very Heavy Woods:                  |          |         |
+  Hickory, Oak, Persimmon, Osage Orange, |          |         |
+  Black Locust, Hackberry, Blue Beech,   |          |         |
+  best of Elm and Ash                    |0.70-0.80 |  42-48  | 3,700
+(_b_) Heavy Woods                        |          |         |
+  Ash, Elm, Cherry, Birch, Maple, Beech, |          |         |
+  Walnut, Sour Gum, Coffee Tree, Honey   |          |         |
+  Locust, best of Southern Pine and      |          |         |
+  Tamarack                               |0.60-0.70 |  36-42  | 3,200
+(_c_) Woods of Medium Weight:            |          |         |
+  Southern Pine, Pitch Pine, Tamarack,   |          |         |
+  Douglas Spruce, Western Hemlock,       |          |         |
+  Sweet Gum, Soft Maple, Sycamore,       |          |         |
+  Sassafras, Mulberry, light grades of   |          |         |
+  Birch and Cherry                       |0.50-0.60 |  30-36  | 2,700
+(_d_) Light Woods:                       |          |         |
+  Norway and Bull Pine, Red Cedar,       |          |         |
+  Cypress, Hemlock, the Heavier Spruces  |          |         |
+  and Firs, Redwood, Basswood, Chestnut, |          |         |
+  Butternut, Tulip, Catalpa, Buckeye,    |          |         |
+  heavier grades of Poplar               |0.40-0.50 |  24-30  | 2,200
+(_e_) Very Light Woods:                   |          |         |
+  White Pine, Spruce, Fir, White Cedar,  |          |         |
+  Poplar                                 |0.30-0.40 |  18-24  | 1,800
+-----------------------------------------+----------+---------+-------
+
+
+                           "FIGURE" IN WOOD
+
+Many theories have been propounded as to the cause of "figure" in
+timber; while it is true that all timber possesses "figure" in some
+degree, which is more noticeable if it be cut in certain ways, yet
+there are some woods in which it is more conspicuous than in others,
+and which for cabinet or furniture work are much appreciated, as it
+adds to the value of the work produced.
+
+The characteristic "figure" of oak is due to the broad and deep
+medullary rays so conspicuous in this timber, and the same applies to
+honeysuckle. Figure due to the same cause is found in sycamore and
+beech, but is not so pronounced. The beautiful figure in "bird's eye
+maple" is supposed to be due to the boring action of insects in the
+early growth of the tree, causing pits or grooves, which in time
+become filled up by being overlain by fresh layers of wood growth;
+these peculiar and unique markings are found only in the older and
+inner portion of the tree.
+
+Pitch pine has sometimes a very beautiful "figure," but it generally
+does not go deep into the timber; walnut has quite a variety of
+"figures," and so has the elm. It is in mahogany, however, that we
+find the greatest variety of "figure," and as this timber is only used
+for furniture and fancy work, a good "figure" greatly enhances its
+value, as firmly figured logs bring fancy prices.
+
+Mahogany, unlike the oak, never draws its "figure" from its small and
+almost unnoticeable medullary rays, but from the twisted condition of
+its fibres; the natural growth of mahogany produces a straight wood;
+what is called "figured" is unnatural and exceptional, and thus adds
+to its value as an ornamental wood. These peculiarities are rarely
+found in the earlier portion of the tree that is near the center,
+being in this respect quite different from maple; they appear when the
+tree is more fully developed, and consist of bundles of woody fibres
+which, instead of being laid in straight lines, behave in an erratic
+manner and are deposited in a twisted form; sometimes it may be caused
+by the intersection of branches, or possibly by the crackling of the
+bark pressing on the wood, and thus moving it out of its natural
+straight course, causing a wavy line which in time becomes
+accentuated.
+
+It will have been observed by most people that the outer portion of a
+tree is often indented by the bark, and the outer rings often follow a
+sinuous course which corresponds to this indention, but in most trees,
+after a few years, this is evened up and the annual rings assume their
+nearly circular form; it is supposed by some that in the case of
+mahogany this is not the case, and that the indentations are even
+accentuated.
+
+The best figured logs of timber are secured from trees which grow in
+firm rocky soil; those growing on low-lying or swampy ground are
+seldom figured. To the practical woodworker the figure in mahogany
+causes some difficulty in planing the wood to a smooth surface; some
+portions plane smooth, others are the "wrong way of the grain."
+
+Figure in wood is effected by the way light is thrown upon it, showing
+light if seen from one direction, and dark if viewed from another, as
+may easily be observed by holding a piece of figured mahogany under
+artificial light and looking at it from opposite directions. The
+characteristic markings on mahogany are "mottle," which is also found
+in sycamore, and is conspicuous on the backs of fiddles and violins,
+and is not in itself valuable; it runs the transverse way of the
+fibres and is probably the effect of the wind upon the tree in its
+early stages of growth. "Roe," which is said to be caused by the
+contortion of the woody fibres, and takes a wavy line parallel to
+them, is also found in the hollow of bent stems and in the root
+structure, and when combined with "mottle" is very valuable. "Dapple"
+is an exaggerated form of mottle. "Thunder shake," "wind shake," or
+"tornado shake" is a rupture of the fibres across the grain, which in
+mahogany does not always break them; the tree swaying in the wind only
+strains its fibres, and thus produces mottle in the wood.
+
+
+
+
+                               SECTION V
+
+                            ENEMIES OF WOOD
+
+
+From the writer's personal investigations of this subject in different
+sections of the country, the damage to forest products of various
+kinds from this cause seems to be far more extensive than is generally
+recognized. Allowing a loss of five per cent on the total value of the
+forest products of the country, which the writer believes to be a
+conservative estimate, it would amount to something over $30,000,000
+annually. This loss differs from that resulting from insect damage to
+natural forest resources, in that it represents more directly a loss
+of money invested in material and labor. In dealing with the insects
+mentioned, as with forest insects in general, the methods which yield
+the best results are those which relate directly to preventing attack,
+as well as those which are unattractive or unfavorable. The insects
+have two objects in their attack: one is to obtain food, the other is
+to prepare for the development of their broods. Different species of
+insects have special periods during the season of activity (March to
+November), when the adults are on the wing in search of suitable
+material in which to deposit their eggs. Some species, which fly in
+April, will be attracted to the trunks of recently felled pine trees
+or to piles of pine sawlogs from trees felled the previous winter.
+They are not attracted to any other kind of timber, because they can
+live only in the bark or wood of pine, and only in that which is in
+the proper condition to favor the hatching of their eggs and the
+normal development of their young. As they fly only in April, they
+cannot injure the logs of trees felled during the remainder of the
+year.
+
+There are also oak insects, which attack nothing but oak; hickory,
+cypress, and spruce insects, etc., which have different habits and
+different periods of flight, and require special conditions of the
+bark and wood for depositing their eggs or for subsequent development
+of their broods. Some of these insects have but one generation in a
+year, others have two or more, while some require more than one year
+for the complete development and transformation. Some species deposit
+their eggs in the bark or wood of trees soon after they are felled or
+before any perceptible change from the normal living tissue has taken
+place; other species are attracted only to dead bark and dead wood of
+trees which have been felled or girdled for several months; others are
+attracted to dry and seasoned wood; while another class will attack
+nothing but very old, dry bark or wood of special kinds and under
+special conditions. Thus it will be seen how important it is for the
+practical man to have knowledge of such of the foregoing facts as
+apply to his immediate interest in the manufacture or utilization of a
+given forest product, in order that he may with the least trouble and
+expense adjust his business methods to meet the requirements for
+preventing losses.
+
+The work of different kinds of insects, as represented by special
+injuries to forest products, is the first thing to attract attention,
+and the distinctive character of this work is easily observed, while
+the insect responsible for it is seldom seen, or it is so difficult to
+determine by the general observer from descriptions or illustrations
+that the species is rarely recognized. Fortunately, the character of
+the work is often sufficient in itself to identify the cause and
+suggest a remedy, and in this section primary consideration is given
+to this phase of the subject.
+
+
+                      Ambrosia or Timber Beetles
+
+    [Illustration: Fig. 22. Work of Ambrosia Beetles in Tulip or
+    Yellow Poplar Wood. _a_, work of _Xyleborus affinis_ and
+    _Xyleborus inermis_; _b_, _Xyleborus obesus_ and work; _c_,
+    bark; _d_, sapwood; _e_, heartwood.]
+
+    [Illustration: Fig. 23. Work of Ambrosia Beetles in Oak. _a_,
+    _Monarthrum mali_ and work; _b_, _Platypus compositus_ and
+    work; _c_, bark; _d_, sapwood; _e_, heartwood; _f_, character
+    of work in wood from injured log.]
+
+The characteristic work of this class of wood-boring beetles is shown
+in Figs. 22 and 23. The injury consists of pinhole and stained-wood
+defects in the sapwood and heartwood of recently felled or girdled
+trees, sawlogs, pulpwood, stave and shingle bolts, green or
+unseasoned lumber, and staves and heads of barrels containing
+alcoholic liquids. The holes and galleries are made by the adult
+parent beetles, to serve as entrances and temporary houses or
+nurseries for the development of their broods of young, which feed on
+a fungus growing on the walls of the galleries.
+
+The growth of this ambrosia-like fungus is induced and controlled by
+the parent beetles, and the young are dependent upon it for food. The
+wood must be in exactly the proper condition for the growth of the
+fungus in order to attract the beetles and induce them to excavate
+their galleries; it must have a certain degree of moisture and other
+favorable qualities, which usually prevail during the period involved
+in the change from living, or normal, to dead or dry wood; such a
+condition is found in recently felled trees, sawlogs, or like crude
+products.
+
+There are two general types or classes of these galleries: one in
+which the broods develop together in the main burrows (see Fig. 22),
+the other in which the individuals develop in short, separate side
+chambers, extending at right angles from the primary galleries (see
+Fig. 23). The galleries of the latter type are usually accompanied by
+a distinct staining of the wood, while those of the former are not.
+
+The beetles responsible for this work are cylindrical in form,
+apparently with a head (the prothorax) half as long as the remainder
+of the body (see Figs. 22, _a_, and 23, _a_).
+
+North American species vary in size from less than one-tenth to
+slightly more than two-tenths of an inch, while some of the
+subtropical and tropical species attain a much larger size. The
+diameter of the holes made by each species corresponds closely to that
+of the body, and varies from about one-twentieth to one-sixteenth of
+an inch for the tropical species.
+
+
+                          Round-headed Borers
+
+    [Illustration: Fig. 24. Work of Round-headed and Flat-headed
+    Borers in Pine. _a_, work of round-headed borer, "sawyer,"
+    _Monohammus spiculatus_, natural size _b_, _Ergates
+    spiculatus_; _c_, work of flat-headed borer, _Buprestis_,
+    larva and adult; _d_, bark; _e_, sapwood; _f_, heartwood.]
+
+The character of the work of this class of wood- and bark-boring grubs
+is shown in Fig. 24. The injuries consist of irregular flattened or
+nearly round wormhole defects in the wood, which sometimes result in
+the destruction of valuable parts of the wood or bark material. The
+sapwood and heartwood of recently felled trees, sawlogs, poles posts,
+mine props, pulpwood and cordwood, also lumber or square timber, with
+bark on the edges, and construction timber in new and old buildings,
+are injured by wormhole defects, while the valuable parts of stored
+oak and hemlock tanbark and certain kinds of wood are converted into
+worm-dust. These injuries are caused by the young or larvae of
+long-horned beetles. Those which infest the wood hatch from eggs
+deposited in the outer bark of logs and like material, and the minute
+grubs hatching therefrom bore into the inner bark, through which they
+extend their irregular burrows, for the purpose of obtaining food from
+the sap and other nutritive material found in the plant tissue. They
+continue to extend and enlarge their burrows as they increase in size,
+until they are nearly or quite full grown. They then enter the wood
+and continue their excavations deep into the sapwood or heartwood
+until they attain their normal size. They then excavate pupa cells in
+which to transform into adults, which emerge from the wood through
+exit holes in the surface. This class of borers is represented by a
+large number of species. The adults, however, are seldom seen by the
+general observer unless cut out of the wood before they have emerged.
+
+
+                          Flat-headed Borers
+
+The work of the flat-headed borers (Fig. 24) is only distinguished
+from that of the preceding by the broad, shallow burrows, and the much
+more oblong form of the exit holes. In general, the injuries are
+similiar, and effect the same class of products, but they are of much
+less importance. The adult forms are flattened, metallic-colored
+beetles, and represent many species, of various sizes.
+
+
+                             Timber Worms
+
+    [Illustration: Fig. 25. Work of Timber Worms in Oak. _a_,
+    work of oak timber worm, _Eupsalis minuta_; _b_, barked
+    surface; _c_, bark; _d_, sapwood timber worm, _Hylocoetus
+    lugubris_, and work; _e_, sapwood.]
+
+The character of the work done by this class is shown in Fig. 25. The
+injury consists of pinhole defects in the sapwood and heartwood of
+felled trees, sawlogs and like material which have been left in the
+woods or in piles in the open for several months during the warmer
+seasons. Stave and shingle bolts and closely piled oak lumber and
+square timbers also suffer from injury of this kind. These injuries
+are made by elongate, slender worms or larvae, which hatch from eggs
+deposited by the adult beetles in the outer bark, or, where there is
+no bark, just beneath the surface of the wood. At first the young
+larvae bore almost invisible holes for a long distance through the
+sapwood and heartwood, but as they increase in size the same holes are
+enlarged and extended until the larvae have attained their full
+growth. They then transform to adults, and emerge through the enlarged
+entrance burrows. The work of these timber worms is distinguished from
+that of the timber beetles by the greater variation in the size of
+holes in the same piece of wood, also by the fact that they are not
+branched from a single entrance or gallery, as are those made by the
+beetles.
+
+    [Illustration: Fig. 26. Work of Powder Post Beetle,
+    _Sinoxylon basilare_, in Hickory Poles, showing Transverse
+    Egg Galleries excavated by the Adult, _a_, entrance; _b_,
+    gallery; _c_, adult.]
+
+    [Illustration: Fig. 27. Work of Powder
+    Post Beetle, _Sinoxylon basilare_, in Hickory Pole. _a_,
+    character of work by larvae; _b_, exit holes made by
+    emerging broods.]
+
+
+                          Powder Post Borers
+
+The character of the work of this class of insects is shown in Figs.
+26, 27, and 28. The injury consists of closely placed burrows, packed
+with borings, or a completely destroyed or powdered condition of the
+wood of seasoned products, such as lumber, crude and finished handle
+and wagon stock, cooperage and wooden truss hoops, furniture, and
+inside finish woodwork, in old buildings, as well as in many other
+crude or finished and utilized woods. This is the work of both the
+adults and young stages of some species, or of the larval stage alone
+of others. In the former, the adult beetles deposit their eggs in
+burrows or galleries excavated for the purpose, as in Figs. 26 and 27,
+while in the latter (Fig. 28) the eggs are on or beneath the surface
+of the wood. The grubs complete the destruction by boring through the
+solid wood in all directions and packing their burrows with the
+powdered wood. When they are full grown they transform to the adult,
+and emerge from the injured material through holes in the surface.
+Some of the species continue to work in the same wood until many
+generations have developed and emerged or until every particle of wood
+tissue has been destroyed and the available nutritive substance
+extracted.
+
+    [Illustration: Fig. 28. Work of Powder Post Beetles, _Lyctus
+    striatus_, in Hickory Handles and Spokes. _a_, larva; _b_,
+    pupa; _c_, adult; _d_, exit holes; _e_, entrance of larvae
+    (vents for borings are exits of parasites); _f_, work of
+    larvae; _g_, wood, completely destroyed; _h_, sapwood; _i_,
+    heartwood.]
+
+
+                    Conditions Favorable for Insect
+           Injury--Crude Products--Round Timber with Bark on
+
+Newly felled trees, sawlogs, stave and heading bolts, telegraph poles,
+posts, and the like material, cut in the fall and winter, and left on
+the ground or in close piles during a few weeks or months in the
+spring or summer, causing them to heat and sweat, are especially
+liable to injury by ambrosia beetles (Figs. 22 and 23), round and
+flat-headed borers (Fig. 24), and timber worms (Fig. 25), as are also
+trees felled in the warm season, and left for a time before working up
+into lumber.
+
+The proper degree of moisture found in freshly cut living or dying
+wood, and the period when the insects are flying, are the conditions
+most favorable for attack. This period of danger varies with the time
+of the year the timber is felled and with the different kinds of
+trees. Those felled in late fall and winter will generally remain
+attractive to ambrosia beetles, and to the adults of round- and
+flat-headed borers during March, April, and May. Those felled in April
+to September may be attacked in a few days after they are felled, and
+the period of danger may not extend over more than a few weeks.
+Certain kinds of trees felled during certain months and seasons are
+never attacked, because the danger period prevails only when the
+insects are flying; on the other hand, if the same kinds of trees are
+felled at a different time, the conditions may be most attractive when
+the insects are active, and they will be thickly infested and ruined.
+
+The presence of bark is absolutely necessary for infestation by most
+of the wood-boring grubs, since the eggs and young stages must occupy
+the outer and inner portions before they can enter the wood. Some
+ambrosia and timber worms will, however, attack barked logs,
+especially those in close piles, and others shaded and protected from
+rapid drying.
+
+The sapwood of pine, spruce, fir, cedar, cypress, and the like
+softwoods is especially liable to injury by ambrosia beetles, while
+the heartwood is sometimes ruined by a class of round-headed borers,
+known as "sawyers." Yellow poplar, oak, chestnut, gum, hickory, and
+most other hardwoods are as a rule attacked by species of ambrosia
+beetles, sawyers, and timber worms, different from those infesting the
+pines, there being but very few species which attack both.
+
+Mahogany and other rare and valuable woods imported from the tropics
+to this country in the form of round logs, with or without bark on,
+are commonly damaged more or less seriously by ambrosia beetles and
+timber worms.
+
+It would appear from the writer's investigations of logs received at
+the mills in this country, that the principal damage is done during a
+limited period--from the time the trees are felled until they are
+placed in fresh or salt water for transportation to the shipping
+points. If, however, the logs are loaded on a vessel direct from the
+shore, or if not left in the water long enough to kill the insects,
+the latter will continue their destructive work during transportation
+to other countries and after they arrive, and until cold weather
+ensues or the logs are converted into lumber.
+
+It was also found that a thorough soaking in sea-water, while it
+usually killed the insects at the time, did not prevent subsequent
+attacks by both foreign and native ambrosia beetles; also, that the
+removal of the bark from such logs previous to immersion did not
+render them entirely immune. Those with the bark off were attacked
+more than those with it on, owing to a greater amount of saline
+moisture retained by the bark.
+
+
+                         How to Prevent Injury
+
+From the foregoing it will be seen that some requisites for preventing
+these insect injuries to round timber are:
+
+     1. To provide for as little delay as possible between the
+     felling of the tree and its manufacture into rough products.
+     This is especially necessary with trees felled from April to
+     September, in the region north of the Gulf States, and from
+     March to November in the latter, while the late fall and
+     winter cutting should all be worked up by March or April.
+
+     2. If the round timber must be left in the woods or on the
+     skidways during the danger period, every precaution should
+     be taken to facilitate rapid drying of the inner bark, by
+     keeping the logs off the ground in the sun, or in loose
+     piles; or else the opposite extreme should be adopted and
+     the logs kept in water.
+
+     3. The immediate removal of all the bark from poles, posts,
+     and other material which will not be seriously damaged by
+     checking or season checks.
+
+     4. To determine and utilize the proper months or seasons to
+     girdle or fell different kinds of trees: Bald cypress in the
+     swamps of the South are "girdled" in order that they may
+     die, and in a few weeks or months dry out and become light
+     enough to float. This method has been extensively adopted in
+     sections where it is the only practicable one by which the
+     timber can be transported to the sawmills. It is found,
+     however, that some of these "girdled" trees are especially
+     attractive to several species of ambrosia beetles (Figs. 22
+     and 23), round-headed borers (Fig. 24) and timber worms
+     (Fig. 25), which cause serious injury to the sapwood or
+     heartwood, while other trees "girdled" at a different time
+     or season are not injured. This suggested to the writer the
+     importance of experiments to determine the proper time to
+     "girdle" trees to avoid losses, and they are now being
+     conducted on an extensive scale by the United States Forest
+     Service, in co-operation with prominent cypress operators in
+     different sections of the cypress-growing region.
+
+
+                               Saplings
+
+Saplings, including hickory and other round hoop-poles and similiar
+products, are subject to serious injuries and destruction by round-
+and flat-headed borers (Fig. 24), and certain species of powder post
+borers (Figs. 26 and 27) before the bark and wood are dead or dry, and
+also by other powder post borers (Fig. 28) after they are dried and
+seasoned. The conditions favoring attack by the former class are those
+resulting from leaving the poles in piles or bundles in or near the
+forest for a few weeks during the season of insect activity, and by
+the latter from leaving them stored in one place for several months.
+
+
+                   Stave, Heading and Shingle Bolts
+
+These are attacked by ambrosia beetles (Figs. 22 and 23), and the oak
+timber worm (Fig. 25, _a_), which, as has been frequently reported,
+cause serious losses. The conditions favoring attack by these insects
+are similiar to those mentioned under "Round Timber." The insects may
+enter the wood before the bolts are cut from the log or afterward,
+especially if the bolts are left in moist, shady places in the woods,
+in close piles during the danger period. If cut during the warm
+season, the bark should be removed and the bolts converted into the
+smallest practicable size and piled in such manner as to facilitate
+rapid drying.
+
+
+                   Unseasoned Products in the Rough
+
+Freshly sawn hardwood, placed in close piles during warm, damp weather
+in July and September, presents especially favorable conditions for
+injury by ambrosia beetles (Figs. 22, _a_, and 23, _a_). This is due
+to the continued moist condition of such material.
+
+Heavy two-inch or three-inch stuff is also liable to attack even in
+loose piles with lumber or cross sticks. An example of the latter was
+found in a valuable lot of mahogany lumber of first grade, the value
+of which was reduced two thirds by injury from a native ambrosia
+beetle. Numerous complaints have been received from different sections
+of the country of this class of injury to oak, poplar, gum, and other
+hardwoods. In all cases it is the moist condition and retarded drying
+of the lumber which induces attack; therefore, any method which will
+provide for the rapid drying of the wood before or after piling will
+tend to prevent losses.
+
+It is important that heavy lumber should, as far as possible, be cut
+in the winter months and piled so that it will be well dried out
+before the middle of March. Square timber, stave and heading bolts,
+with the bark on, often suffer from injuries by flat- or round-headed
+borers, hatching from eggs deposited in the bark of the logs before
+they are sawed and piled. One example of serious damage and loss was
+reported in which white pine staves for paint buckets and other small
+wooden vessels, which had been sawed from small logs, and the bark
+left on the edges, were attacked by a round-headed borer, the adults
+having deposited their eggs in the bark after the stock was sawn and
+piled. The character of the injury is shown in Fig. 29. Another
+example was reported from a manufacturer in the South, where the
+pieces of lumber which had strips of bark on one side were seriously
+damaged by the same kind of borer, the eggs having been deposited in
+the logs before sawing or in the bark after the lumber was piled. If
+the eggs are deposited in the logs, and the borers have entered the
+inner bark or the wood before sawing, they may continue their work
+regardless of methods of piling, but if such lumber is cut from new
+logs and placed in the pile while green, with the bark surface up, it
+will be much less liable to attack than if piled with the bark edges
+down. This liability of lumber with bark edges or sides to be attacked
+by insects suggests the importance of the removal of the bark, to
+prevent damage, or, if this is not practicable, the lumber with the
+bark on the sides should be piled in open, loose piles with the bark
+up, while that with the bark on the edges should be placed on the
+outer edges of the piles, exposed to the light and air.
+
+    [Illustration: Fig. 29. Work of Round-headed Borers,
+    _Callidium antennatum_, in White Pine Bucket Staves from New
+    Hampshire. _a_, where egg was deposited in bark; _b_, larval
+    mine; _c_, pupal cell; _d_, exit in bark; _e_, adult.]
+
+In the Southern States it is difficult to keep green timber in the
+woods or in piles for any length of time, because of the rapidity
+which wood-destroying fungi attack it. This is particularly true
+during the summer season, when the humidity is greatest. There is
+really no easily-applied, general specific for these summer troubles
+in the handling of wood, but there are some suggestions that are worth
+while that it may be well to mention. One of these, and the most
+important, is to remove all the bark from the timber that has been
+cut, just as soon as possible after felling. And, in this, emphasis
+should be laid on the ALL, as a piece of bark no larger than a man's
+little finger will furnish an entering place for insects, and once
+they get in, it is a difficult matter to get rid of them, for they
+seldom stop boring until they ruin the stick. And again, after the
+timber has been felled and the bark removed, it is well to get it to
+the mill pond or cut up into merchantable sizes and on to the pile as
+soon as possible. What is wanted is to get the timber up off the
+ground, to a place where it can get plenty of air, to enable the sap
+to dry up before it sours; and, besides, large units of wood are more
+likely to crack open on the ends from the heat than they would if cut
+up into the smaller units for merchandizing.
+
+A moist condition of lumber and square timber, such as results from
+close or solid piles, with the bottom layers on the ground or on
+foundations of old decaying logs or near decaying stumps and logs,
+offers especially favorable conditions for the attack of white ants.
+
+
+                    Seasoned Products in the Rough
+
+Seasoned or dry timber in stacks or storage is liable to injury by
+powder post borers (Fig. 28). The conditions favoring attack are: (1)
+The presence of a large proportion of sapwood, as in hickory, ash, and
+similiar woods; (2) material which is two or more years old, or that
+which has been kept in one place for a long time; (3) access to old
+infested material. Therefore, such stock should be frequently examined
+for evidence of the presence of these insects. This is always
+indicated by fine, flour-like powder on or beneath the piles, or
+otherwise associated with such material. All infested material should
+be at once removed and the infested parts destroyed by burning.
+
+
+              Dry Cooperage Stock and Wooden Truss Hoops
+
+These are especially liable to attack and serious injury by powder
+post borers (Fig. 28), under the same or similiar conditions as the
+preceding.
+
+
+       Staves and Heads of Barrels containing Alcoholic Liquids
+
+These are liable to attack by ambrosia beetles (Figs. 22, _a_, and 23,
+_a_), which are attracted by the moist condition and possibly by the
+peculiar odor of the wood, resembling that of dying sapwood of trees
+and logs, which is their normal breeding place.
+
+There are many examples on record of serious losses of liquors from
+leakage caused by the beetles boring through the staves and heads of
+the barrels and casks in cellars and storerooms.
+
+The condition, in addition to the moisture of the wood, which is
+favorable for the presence of the beetles, is proximity to their
+breeding places, such as the trunks and stumps of recently felled or
+dying oak, maple, and other hardwood or deciduous trees; lumber yards,
+sawmills, freshly-cut cordwood, from living or dead trees, and forests
+of hardwood timber. Under such conditions the beetles occur in great
+numbers, and if the storerooms and cellars in which the barrels are
+kept stored are damp, poorly ventilated, and readily accessible to
+them, serious injury is almost certain to follow.
+
+
+
+
+                              SECTION VI
+
+                             WATER IN WOOD
+
+                     DISTRIBUTION OF WATER IN WOOD
+
+
+                  Local Distribution of Water in Wood
+
+As seasoning means essentially the more or less rapid evaporation of
+water from wood, it will be necessary to discuss at the very outset
+where water is found in wood, and its local seasonal distribution in a
+tree.
+
+Water may occur in wood in three conditions: (1) It forms the greater
+part (over 90 per cent) of the protoplasmic contents of the living
+cells; (2) it saturates the walls of all cells; and (3) it entirely or
+at least partly fills the cavities of the lifeless cells, fibres, and
+vessels.
+
+In the sapwood of pine it occurs in all three forms; in the heartwood
+only in the second form, it merely saturates the walls.
+
+Of 100 pounds of water associated with 100 pounds of dry wood
+substance taken from 200 pounds of fresh sapwood of white pine, about
+35 pounds are needed to saturate the cell walls, less than 5 pounds
+are contained in the living cells, and the remaining 60 pounds partly
+fill the cavities of the wood fibres. This latter forms the sap as
+ordinarily understood.
+
+The wood next to the bark contains the most water. In the species
+which do not form heartwood, the decrease toward the pith is gradual,
+but where heartwood is formed the change from a more moist to a drier
+condition is usually quite abrupt at the sapwood limit.
+
+In long-leaf pine, the wood of the outer one inch of a disk may
+contain 50 per cent of water, that of the next, or the second inch,
+only 35 per cent, and that of the heartwood, only 20 per cent. In
+such a tree the amount of water in any one section varies with the
+amount of sapwood, and is greater for the upper than the lower cuts,
+greater for the limbs than the stems, and greatest of all in the
+roots.
+
+Different trees, even of the same kind and from the same place, differ
+as to the amount of water they contain. A thrifty tree contains more
+water than a stunted one, and a young tree more than on old one, while
+the wood of all trees varies in its moisture relations with the season
+of the year.
+
+
+                Seasonal Distribution of Water in Wood
+
+It is generally supposed that trees contain less water in winter than
+in summer. This is evidenced by the popular saying that "the sap is
+down in the winter." This is probably not always the case; some trees
+contain as much water in winter as in summer, if not more. Trees
+normally contain the greatest amount of water during that period when
+the roots are active and the leaves are not yet out. This activity
+commonly begins in January, February, and March, the exact time
+varying with the kind of timber and the local atmospheric conditions.
+And it has been found that green wood becomes lighter or contains less
+water in late spring or early summer, when transpiration through the
+foliage is most rapid. The amount of water at any one season, however,
+is doubtless much influenced by the amount of moisture in the soil.
+The fact that the bark peels easily in the spring depends on the
+presence of incomplete, soft tissue found between wood and bark during
+this season, and has little to do with the total amount of water
+contained in the wood of the stem.
+
+Even in the living tree a flow of sap from a cut occurs only in
+certain kinds of trees and under special circumstances. From boards,
+felled timber, etc., the water does not flow out, as is sometimes
+believed, but must be evaporated. The seeming exceptions to this rule
+are mostly referable to two causes; clefts or "shakes" will allow
+water contained in them to flow out, and water is forced out of sound
+wood, if very sappy, whenever the wood is warmed, just as water flows
+from green wood when put in a stove.
+
+
+                          Composition of Sap
+
+The term "sap" is an ambiguous expression. The sap in the tree
+descends through the bark, and except in early spring is not present
+in the wood of the tree except in the medullary rays and living
+tissues in the "sapwood."
+
+What flows through the "sapwood" is chiefly water brought from the
+soil. It is not pure water, but contains many substances in solution,
+such as mineral salts, and in certain species--maple, birch, etc., it
+also contains at certain times a small percentage of sugar and other
+organic matter.
+
+The water rises from the roots through the sapwood to the leaves,
+where it is converted into true "sap" which descends through the bark
+and feeds the living tissues between the bark and the wood, which
+tissues make the annual growth of the trunk. The wood itself contains
+very little true sap and the heartwood none.
+
+The wood contains, however, mineral substances, organic acids,
+volatile oils and gums, as resin, cedar oil, etc.
+
+All the conifers--pines, cedars, junipers, cypresses, sequoias, yews,
+and spruces--contain resin. The sap of deciduous trees--those which
+shed their leaves at stated seasons--is lacking in this element, and
+its constituents vary greatly in the different species. But there is
+one element common to all trees, and for that matter to almost all
+plant growth, and that is albumen.
+
+Both resin and albumen, as they exist in the sap of woods, are soluble
+in water; and both harden with heat, much the same as the white of an
+egg, which is almost pure albumen.
+
+These organic substances are the dissolved reserve food, stored during
+the winter in the pith rays, etc., of the wood and bark; generally but
+a mere trace of them is to be found. From this it appears that the
+solids contained in the sap, such as albumen, gum, sugar, etc.,
+cannot exercise the influence on the strength of the wood which is so
+commonly claimed for them.
+
+
+                      Effects of Moisture on Wood
+
+The question of the effect of moisture upon the strength and stiffness
+of wood offers a wide scope for study, and authorities consulted
+differ in conclusions. Two authorities give the tensile strength in
+pounds per square inch for white oak as 10,000 and 19,500,
+respectively; for spruce, 8,000 to 19,500, and other species in
+similiar startling contrasts.
+
+Wood, we are told, is composed of organic products. The chief material
+is cellulose, and this in its natural state in the living plant or
+green wood contains from 25 to 35 per cent of its weight in moisture.
+The moisture renders the cellulose substance pliable. What the
+physical action of the water is upon the molecular structure of
+organic material, to render it softer and more pliable, is largely a
+matter of conjecture.
+
+The strength of a timber depends not only upon its relative freedom
+from imperfections, such as knots, crookedness of grain, decay,
+wormholes or ring-shakes, but also upon its density; upon the rate at
+which it grew, and upon the arrangement of the various elements which
+compose it.
+
+The factors effecting the strength of wood are therefore of two
+classes: (1) Those inherent in the wood itself and which may cause
+differences to exist between two pieces from the same species of wood
+or even between the two ends of a piece, and (2) those which are
+foreign to the wood itself, such as moisture, oils, and heat.
+
+Though the effect of moisture is generally temporary, it is far more
+important than is generally realized. So great, indeed, is the effect
+of moisture that under some conditions it outweighs all the other
+causes which effect strength, with the exception, perhaps of decided
+imperfections in the wood itself.
+
+
+                  The Fibre Saturation Point in Wood
+
+Water exists in green wood in two forms: (1) As liquid water contained
+in the cavities of the cells or pores, and (2) as "imbibed" water
+intimately absorbed in the substance of which the wood is composed.
+The removal of the free water from the cells or pores will evidently
+have no effect upon the physical properties or shrinkage of the wood,
+but as soon as any of the "imbibed" moisture is removed from the cell
+walls, shrinkage begins to take place and other changes occur. The
+strength also begins to increase at this time.
+
+The point where the cell walls or wood substance becomes saturated is
+called the "fibre saturation point," and is a very significant point
+in the drying of wood.
+
+It is easy to remove the free water from woods which will stand a high
+temperature, as it is only necessary to heat the wood slightly above
+the boiling point in a closed vessel, which will allow the escape of
+the steam as it is formed, but will not allow dry air to come in
+contact with the wood, so that the surface will not become dried below
+its saturation point. This can be accomplished with most of the
+softwoods, but not as a rule with the hardwoods, as they are injured
+by the temperature necessary.
+
+The chief difficulties are encountered in evaporating the "imbibed"
+moisture and also where the free water has to be removed through its
+gradual transfusion instead of boiling. As soon as the imbibed
+moisture begins to be extracted from any portion, shrinkage takes
+place and stresses are set up in the wood which tend to cause
+checking.
+
+The fibre saturation point lies between moisture conditions of 25 and
+30 per cent of the dry weight of the wood, depending on the species.
+Certain species of eucalyptus, and probably other woods, however,
+appear to be exceptional in this respect, in that shrinkage begins to
+take place at a moisture condition of 80 to 90 per cent of the dry
+weight.
+
+
+
+
+                              SECTION VII
+
+                           WHAT SEASONING IS
+
+
+Seasoning is ordinarily understood to mean drying. When exposed to the
+sun and air, the water in green wood rapidly evaporates. The rate of
+evaporation will depend on: (1) the kind of wood; (2) the shape and
+thickness of the timber; and (3) the conditions under which the wood
+is placed or piled.
+
+Pieces of wood completely surrounded by air, exposed to the wind and
+the sun, and protected by a roof from rain and snow, will dry out very
+rapidly, while wood piled or packed close together so as to exclude
+the air, or left in the shade and exposed to rain and snow, will dry
+out very slowly and will also be subject to mould and decay.
+
+But seasoning implies other changes besides the evaporation of water.
+Although we have as yet only a vague conception as to the exact nature
+of the difference between seasoned and unseasoned wood, it is very
+probable that one of these consists in changes in the albuminous
+substances in the wood fibres, and possibly also in the tannins,
+resins, and other incrusting substances. Whether the change in these
+substances is merely a drying-out, or whether it consists in a partial
+decomposition is at yet undetermined. That the change during the
+seasoning process is a profound one there can be no doubt, because
+experience has shown again and again that seasoned wood fibre is very
+much more permeable, both for liquids and gases than the living,
+unseasoned fibre.
+
+One can picture the albuminous substances as forming a coating which
+dries out and possibly disintegrates when the wood dries. The
+drying-out may result in considerable shrinkage, which may make the
+wood fibre more porous. It is also possible that there are oxidizing
+influences at work within these substances which result in their
+disintegration. Whatever the exact nature of the change may be, one
+can say without hesitation that exposure to the wind and air brings
+about changes in the wood, which are of such a nature that the wood
+becomes drier and more permeable.
+
+When seasoned by exposure to live steam, similiar changes may take
+place; the water leaves the wood in the form of steam, while the
+organic compounds in the walls probably coagulate or disintegrate
+under the high temperature.
+
+The most effective seasoning is without doubt that obtained by the
+uniform, slow drying which takes place in properly constructed piles
+outdoors, under exposure to the winds and the sun and under cover from
+the rain and snow, and is what has been termed "air-seasoning." By
+air-seasoning oak and similiar hardwoods, nature performs certain
+functions that cannot be duplicated by any artificial means. Because
+of this, woods of this class cannot be successfully kiln-dried green
+from the saw.
+
+In drying wood, the free water within the cells passes through the
+cell walls until the cells are empty, while the cell walls remain
+saturated. When all the free water has been removed, the cell walls
+begin to yield up their moisture. Heat raises the absorptive power of
+the fibres and so aids the passage of water from the interior of the
+cells. A confusion in the word "sap" is to be found in many
+discussions of kiln-drying; in some instances it means water, in other
+cases it is applied to the organic substances held in a water solution
+in the cell cavities. The term is best confined to the organic
+substances from the living cell. These substances, for the most part
+of the nature of sugar, have a strong attraction for water and water
+vapor, and so retard drying and absorb moisture into dried wood. High
+temperatures, especially those produced by live steam, appear to
+destroy these organic compounds and therefore both to retard and to
+limit the reabsorption of moisture when the wood is subsequently
+exposed to the atmosphere.
+
+Air-dried wood, under ordinary atmospheric temperatures, retains from
+10 to 20 per cent of moisture, whereas kiln-dried wood may have no
+more than 5 per cent as it comes from the kiln. The exact figures for
+a given species depend in the first case upon the weather conditions,
+and in the second case upon the temperature in the kiln and the time
+during which the wood is exposed to it. When wood that has been
+kiln-dried is allowed to stand in the open, it apparently ceases to
+reabsorb moisture from the air before its moisture content equals that
+of wood which has merely been air-dried in the same place, and under
+the same conditions, in other words kiln-dried wood will not absorb as
+much moisture as air-dried wood under the same conditions.
+
+
+            Difference between Seasoned and Unseasoned Wood
+
+Although it has been known for a long time that there is a marked
+difference in the length of life of seasoned and of unseasoned wood,
+the consumers of wood have shown very little interest in its
+seasoning, except for the purpose of doing away with the evils which
+result from checking, warping, and shrinking. For this purpose both
+kiln-drying and air-seasoning are largely in use.
+
+The drying of material is a subject which is extremely important to
+most industries, and in no industry is it of more importance than in
+the lumber trade. Timber drying means not only the extracting of so
+much water, but goes very deeply into the quality of the wood, its
+workability and its cell strength, etc.
+
+Kiln-drying, which dries the wood at a uniformly rapid rate by
+artificially heating it in inclosed rooms, has become a part of almost
+every woodworking industry, as without it the construction of the
+finished product would often be impossible. Nevertheless much
+unseasoned or imperfectly seasoned wood is used, as is evidenced by
+the frequent shrinkage and warping of the finished articles. This is
+explained to a certain extent by the fact that the manufacturer is
+often so hard pressed for his product that he is forced to send out an
+inferior article, which the consumer is willing to accept in that
+condition rather than to wait several weeks or months for an article
+made up of thoroughly seasoned material, and also that dry kilns are
+at present constructed and operated largely without thoroughgoing
+system.
+
+Forms of kilns and mode of operation have commonly been copied by one
+woodworking plant after the example of some neighboring establishment.
+In this way it has been brought about that the present practices have
+many shortcomings. The most progressive operators, however, have
+experimented freely in the effort to secure special results desirable
+for their peculiar products. Despite the diversity of practice, it is
+possible to find among the larger and more enterprising operators a
+measure of agreement, as to both methods and results, and from this to
+outline the essentials of a correct theory. As a result, properly
+seasoned wood commands a high price, and in some cases cannot be
+obtained at all.
+
+Wood seasoned out of doors, which by many is supposed to be much
+superior to kiln-dried material, is becoming very scarce, as the
+demand for any kind of wood is so great that it is thought not to pay
+to hold it for the time necessary to season it properly. How long this
+state of affairs is going to last it is difficult to say, but it is
+believed that a reaction will come when the consumer learns that in
+the long run it does not pay to use poorly seasoned material. Such a
+condition has now arisen in connection with another phase of the
+seasoning of wood; it is a commonly accepted fact that dry wood will
+not decay nearly so fast as wet or green wood; nevertheless, the
+immense superiority of seasoned over unseasoned wood for all purposes
+where resistance to decay is necessary has not been sufficiently
+recognized. In the times when wood of all kinds was both plentiful and
+cheap, it mattered little in most cases how long it lasted or resisted
+decay. Wood used for furniture, flooring, car construction, cooperage,
+etc., usually got some chance to dry out before or after it was placed
+in use. The wood which was exposed to decaying influences was
+generally selected from those woods which, whatever their other
+qualities might be, would resist decay longest.
+
+To-day conditions have changed, so that wood can no longer be used to
+the same extent as in former years. Inferior woods with less lasting
+qualities have been pressed into service. Although haphazard methods
+of cutting and subsequent use are still much in vogue, there are many
+signs that both lumbermen and consumers are awakening to the fact that
+such carelessness and wasteful methods of handling wood will no longer
+do, and must give way to more exact and economical methods. The reason
+why many manufacturers and consumers of wood are still using the older
+methods is perhaps because of long custom, and because they have not
+yet learned that, though the saving to be obtained by the application
+of good methods has at all times been appreciable, now, when wood is
+more valuable, a much greater saving is possible. The increased cost
+of applying economical methods is really very slight, and is many
+times exceeded by the value of the increased service which can be
+secured through its use.
+
+
+                    Manner of Evaporation of Water
+
+The evaporation of water from wood takes place largely through the
+ends, _i.e._, in the direction of the longitudinal axis of the wood
+fibres. The evaporation from the other surfaces takes place very
+slowly out of doors, and with greater rapidity in a dry kiln. The rate
+of evaporation differs both with the kind of timber and its shape;
+that is, thin material will dry more rapidly than heavier stock.
+Sapwood dries faster than heartwood, and pine more rapidly than oak or
+other hardwoods.
+
+Tests made show little difference in the rate of evaporation in sawn
+and hewn stock, the results, however, not being conclusive. Air-drying
+out of doors takes from two months to a year, the time depending on
+the kind of timber, its thickness, and the climatic conditions. After
+wood has reached an air-dry condition it absorbs water in small
+quantities after a rain or during damp weather, much of which is
+immediately lost again when a few warm, dry days follow. In this way
+wood exposed to the weather will continue to absorb water and lose it
+for indefinite periods.
+
+When soaked in water, seasoned woods absorb water rapidly. This at
+first enters into the wood through the cell walls; when these are
+soaked, the water will fill the cell lumen, so that if constantly
+submerged the wood may become completely filled with water.
+
+The following figures show the gain in weight by absorption of several
+coniferous woods, air-dry at the start, expressed in per cent of the
+kiln-dry weight:
+
+                    ABSORPTION OF WATER BY DRY WOOD
+---------------------------------------------------------------
+                  | White Pine | Red Cedar | Hemlock | Tamarack
+---------------------------------------------------------------
+Air-dried         |    108     |   109     |   111   |   108
+Kiln-dried        |    100     |   100     |   100   |   100
+In water 1 day    |    135     |   120     |   133   |   129
+In water 2 days   |    147     |   126     |   144   |   136
+In water 3 days   |    154     |   132     |   149   |   142
+In water 4 days   |    162     |   137     |   154   |   147
+In water 5 days   |    165     |   140     |   158   |   150
+In water 7 days   |    176     |   143     |   164   |   156
+In water 9 days   |    179     |   147     |   168   |   157
+In water 11 days  |    184     |   149     |   173   |   159
+In water 14 days  |    187     |   150     |   176   |   159
+In water 17 days  |    192     |   152     |   176   |   161
+In water 25 days  |    198     |   155     |   180   |   161
+In water 30 days  |    207     |   158     |   183   |   166
+---------------------------------------------------------------
+
+
+                        Rapidity of Evaporation
+
+The rapidity with which water is evaporated, that is, the rate of
+drying, depends on the size and shape of the piece and on the
+structure of the wood. An inch board dries more than four times as
+fast as a four-inch plank, and more than twenty times as fast as a
+ten-inch timber. White pine dries faster than oak. A very moist piece
+of pine or oak will, during one hour, lose more than four times as
+much water per square inch from the cross-section, but only one half
+as much from the tangential as from the radial section. In a long
+timber, where the ends or cross-sections form but a small part of the
+drying surface, this difference is not so evident. Nevertheless, the
+ends dry and shrink first, and being opposed in this shrinkage by the
+more moist adjoining parts, they check, the cracks largely
+disappearing as seasoning progresses.
+
+High temperatures are very effective in evaporating the water from
+wood, no matter how humid the air, and a fresh piece of sapwood may
+lose weight in boiling water, and can be dried to quite an extent in
+hot steam.
+
+In drying chemicals or fabrics, all that is required is to provide
+heat enough to vaporize the moisture and circulation enough to carry
+off the vapor thus secured, and the quickest and most economical means
+to these ends may be used. While on the other hand, in drying wood,
+whether in the form of standard stock or the finished product, the
+application of the requisite heat and circulation must be carefully
+regulated throughout the entire process, or warping and checking are
+almost certain to result. Moreover, wood of different shapes and
+thicknesses is very differently effected by the same treatment.
+Finally, the tissues composing the wood, which vary in form and
+physical properties, and which cross each other in regular directions,
+exert their own peculiar influences upon its behavior during drying.
+With our native woods, for instance, summer-wood and spring-wood show
+distinct tendencies in drying, and the same is true in a less degree
+of heartwood, as contrasted with sapwood. Or, again, pronounced
+medullary rays further complicate the drying problem.
+
+
+               Physical Properties that influence Drying
+
+The principal properties which render the drying of wood peculiarly
+difficult are: (1) The irregular shrinkage; (2) the different ways in
+which water is contained; (3) the manner in which moisture transfuses
+through the wood from the center to the surface; (4) the plasticity of
+the wood substance while moist and hot; (5) the changes which take
+place in the hygroscopic and chemical nature of the surface; and (6)
+the difference produced in the total shrinkage by different rates of
+drying.
+
+The shrinkage is unequal in different directions and in different
+portions of the same piece. It is greatest in the circumferential
+direction of the tree, being generally twice as great in this
+direction as in the radial direction. In the longitudinal direction,
+for most woods, it is almost negligible, being from 20 to over 100
+times as great circumferentially as longitudinally.
+
+There is a great variation in different species in this respect.
+Consequently, it follows from necessity that large internal strains
+are set up when the wood shrinks, and were it not for its plasticity
+it would rupture. There is an enormous difference in the total amount
+of shrinkage of different species of wood, varying from a shrinkage of
+only 7 per cent in volume, based on the green dimensions, in the case
+of some of the cedars to nearly 50 per cent in the case of some
+species of eucalyptus.
+
+When the free water in the capillary spaces of the wood fibre is
+evaporated it follows the laws of evaporation from capillary spaces,
+except that the passages are not all free passages, and much of the
+water has to pass out by a process of transfusion through the moist
+cell walls. These cell walls in the green wood completely surround the
+cell cavities so that there are no openings large enough to offer a
+passage to water or air.
+
+The well-known "pits" in the cell walls extend through the secondary
+thickening only, and not through the primary walls. This statement
+applies to the tracheids and parenchyma cells in the conifer
+(gymnosperms), and to the tracheids, parenchyma cells, and the wood
+fibres in the broad-leaved trees (angiosperms); the vessels in the
+latter, however, form open passages except when clogged by ingrowth
+called tyloses, and the resin canals in the former sometimes form
+occasional openings.
+
+By heating the wood above the boiling point, corresponding to the
+external pressure, the free water passes through the cell walls more
+readily.
+
+To remove the moisture from the wood substance requires heat in
+addition to the latent heat of evaporation, because the molecules of
+moisture are so intimately associated with the molecules, minute
+particles composing the wood, that energy is required to separate them
+therefrom.
+
+Carefully conducted experiments show this to be from 16.6 to 19.6
+calories per grain of dry wood in the case of beech, long-leaf pine,
+and sugar maple.
+
+The difficulty imposed in drying, however, is not so much the
+additional heat required as it is in the rate at which the water
+transfuses through the solid wood.
+
+
+
+
+                             SECTION VIII
+
+                        ADVANTAGES IN SEASONING
+
+
+Three most important advantages of seasoning have already been made
+apparent:
+
+     1. Seasoned timber lasts much longer than unseasoned. Since
+     the decay of timber is due to the attacks of wood-destroying
+     fungi, and since the most important condition of the growth
+     of these fungi is water, anything which lessens the amount
+     of water in wood aids in its preservation.
+
+     2. In the case of treated timber, seasoning before treatment
+     greatly increases the effectiveness of the ordinary methods
+     of treatment, and seasoning after treatment prevents the
+     rapid leaching out of the salts introduced to preserve the
+     timber.
+
+     3. The saving in freight where timber is shipped from one
+     place to another. Few persons realize how much water green
+     wood contains, or how much it will lose in a comparatively
+     short time. Experiments along this line with lodge-pole
+     pine, white oak, and chestnut gave results which were a
+     surprise to the companies owning the timber.
+
+Freight charges vary considerably in different parts of the country;
+but a decrease of 35 to 40 per cent in weight is important enough to
+deserve everywhere serious consideration from those in charge of
+timber operations.
+
+When timber is shipped long distances over several roads, as is coming
+to be more and more the case, the saving in freight will make a
+material difference in the cost of lumber operations, irrespective of
+any other advantages of seasoning.
+
+
+                 Prevention of Checking and Splitting
+
+Under present methods much timber is rendered unfit for use by
+improper seasoning. Green timber, particularly when cut during
+January, February, and March, when the roots are most active, contains
+a large amount of water. When exposed to the sun and wind or to high
+temperatures in a drying room, the water will evaporate more rapidly
+from the outer than from the inner parts of the piece, and more
+rapidly from the ends than from the sides. As the water evaporates,
+the wood shrinks, and when the shrinkage is not fairly uniform the
+wood cracks and splits.
+
+When wet wood is piled in the sun, evaporation goes on with such
+unevenness that the timbers split and crack in some cases so badly as
+to become useless for the purpose for which it was intended. Such
+uneven drying can be prevented by careful piling, keeping the logs
+immersed in a log pond until wanted, or by piling or storing under an
+open shed so that the sun cannot get at them.
+
+Experiments have also demonstrated that injury to stock in the way of
+checking and splitting always develops immediately after the stock is
+taken into the dry kiln, and is due to the degree of humidity being
+too low.
+
+The receiving end of the kiln should always be kept moist, where the
+stock has not been steamed before being put into the kiln, as when the
+air is too dry it tends to dry the outside of the stock first--which
+is termed "case-hardening"--and in so doing shrinks and closes up the
+pores. As the material is moved down the kiln (as in the case of
+"progressive kilns"), it absorbs a continually increasing amount of
+heat, which tends to drive off the moisture still present in the
+center of the piece, the pores on the outside having been closed up,
+there is no exit for the vapor or steam that is being rapidly formed
+in the center of the piece. It must find its way out in some manner,
+and in doing so sets up strains, which result either in checking or
+splitting. If the humidity had been kept higher, the outside of the
+piece would not have dried so quickly, and the pores would have
+remained open for the exit of the moisture from the interior of the
+piece, and this trouble would have been avoided. (See also article
+following.)
+
+
+                           Shrinkage of Wood
+
+Since in all our woods, cells with thick walls and cells with thin
+walls are more or less intermixed, and especially as the spring-wood
+and summer-wood nearly always differ from each other in this respect,
+strains and tendencies to warp are always active when wood dries out,
+because the summer-wood shrinks more than the spring-wood, and heavier
+wood in general shrinks more than light wood of the same kind.
+
+If a thin piece of wood after drying is placed upon a moist surface,
+the cells on the under side of the piece take up moisture and swell
+before the upper cells receive any moisture. This causes the under
+side of the piece to become longer than the upper side, and as a
+consequence warping occurs. Soon, however, the moisture penetrates to
+all the cells and the piece straightens out. But while a thin board of
+pine curves laterally it remains quite straight lengthwise, since in
+this direction both shrinkage and swelling are small. If one side of a
+green board is exposed to the sun, warping is produced by the removal
+of water and consequent shrinkage of the side exposed; this may be
+eliminated by the frequent turning of the topmost pieces of the piles
+in order that they may be dried evenly.
+
+As already stated, wood loses water faster from the ends than from the
+longitudinal faces. Hence the ends shrink at a different rate from the
+interior parts. The faster the drying at the surface, the greater is
+the difference in the moisture of the different parts, and hence the
+greater the strains and consequently also the greater amount of
+checking. This becomes very evident when freshly cut wood is placed in
+the sun, and still more when put into a hot, dry kiln. While most of
+these smaller checks are only temporary, closing up again, some large
+radial checks remain and even grow larger as drying progresses. Their
+cause is a different one and will presently be explained. The
+temporary checks not only appear at the ends, but are developed on
+the sides also, only to a much smaller degree. They become especially
+annoying on the surface of thick planks of hardwoods, and also on
+peeled logs when exposed to the sun.
+
+So far we have considered the wood as if made up only of parallel
+fibres all placed longitudinally in the log. This, however, is not the
+case. A large part of the wood is formed by the medullary or pith
+rays. In pine over 15,000 of these occur on a square inch of a
+tangential section, and even in oak the very large rays, which are
+readily visible to the eye, represent scarcely a hundredth part of the
+number which a microscope reveals, as the cells of these rays have
+their length at right angles to the direction of the wood fibres.
+
+If a large pith ray of white oak is whittled out and allowed to dry,
+it is found to shrink greatly in its width, while, as we have stated,
+the fibres to which the ray is firmly grown in the wood do not shrink
+in the same direction. Therefore, in the wood, as the cells of the
+pith ray dry they pull on the longitudinal fibres and try to shorten
+them, and, being opposed by the rigidity of the fibres, the pith ray
+is greatly strained. But this is not the only strain it has to bear.
+Since the fibres shrink as much again as the pith ray, in this its
+longitudinal direction, the fibres tend to shorten the ray, and the
+latter in opposing this prevents the former from shrinking as much as
+they otherwise would.
+
+Thus the structure is subjected to two severe strains at right angles
+to each other, and herein lies the greatest difficulty of wood
+seasoning, for whenever the wood dries rapidly these fibres have not
+the chance to "give" or accommodate themselves, and hence fibres and
+pith rays separate and checking results, which, whether visible or
+not, are detrimental in the use of the wood.
+
+The contraction of the pith rays parallel to the length of the board
+is probably one of the causes of the small amount of longitudinal
+shrinkage which has been observed in boards. This smaller shrinkage of
+the pith rays along the radius of the log (the length of the pith
+ray), opposing the shrinkage of the fibres in this direction, becomes
+one of the causes of the second great trouble in wood seasoning,
+namely, the difference in the shrinkage along the radius and that
+along the rings or tangent. This greater tangential shrinkage appears
+to be due in part to the causes just mentioned, but also to the fact
+that the greatly shrinking bands of summer-wood are interrupted along
+the radius by as many bands of porous spring-wood, while they are
+continuous in the tangential direction. In this direction, therefore,
+each such band tends to shrink, as if the entire piece were composed
+of summer-wood, and since the summer-wood represents the greater part
+of the wood substance, this greater tendency to tangential shrinkage
+prevails.
+
+The effect of this greater tangential shrinkage effects every phase of
+woodworking. It leads to permanent checks and causes the log or piece
+to split open on drying. Sawed in two, the flat sides of the log
+become convex; sawed into timber, it checks along the median line of
+the four faces, and if converted into boards, the latter checks
+considerably from the end through the center, all owing to the greater
+tangential shrinkage of the wood.
+
+Briefly, then, shrinkage of wood is due to the fact that the cell
+walls grow thinner on drying. The thicker cell walls and therefore the
+heavier wood shrinks most, while the water in the cell cavities does
+not influence the volume of the wood.
+
+Owing to the great difference of cells in shape, size, and thickness
+of walls, and still more in their arrangement, shrinkage is not
+uniform in any kind of wood. This irregularity produces strains, which
+grow with the difference between adjoining cells and are greatest at
+the pith rays. These strains cause warping and checking, but exist
+even where no outward signs are visible. They are greater if the wood
+is dried rapidly than if dried slowly, but can never be entirely
+avoided.
+
+Temporary checks are caused by the more rapid drying of the outer
+parts of any stick; permanent checks are due to the greater shrinkage,
+tangentially, along the rings than along the radius. This, too, is the
+cause of most of the ordinary phenomena of shrinkage, such as the
+difference in behavior of the entire and quartered logs, "bastard"
+(tangent) and rift (radial) boards, etc., and explains many of the
+phenomena erroneously attributed to the influence of bark, or of the
+greater shrinkage of outer and inner parts of any log.
+
+Once dry, wood may be swelled again to its original size by soaking in
+water, boiling, or steaming. Soaked pieces on drying shrink again as
+before; boiled and steamed pieces do the same, but to a slightly less
+degree. Neither hygroscopicity, _i.e._, the capacity of taking up
+water, nor shrinkage of wood can be overcome by drying at temperatures
+below 200 degrees Fahrenheit. Higher temperatures, however, reduce
+these qualities, but nothing short of a coaling heat robs wood of the
+capacity to shrink and swell.
+
+Rapidly dried in a kiln, the wood of oak and other hardwoods
+"case-harden," that is, the outer part dries and shrinks before the
+interior has a chance to do the same, and thus forms a firm shell or
+case of shrunken, commonly checked wood around the interior. This
+shell does not prevent the interior from drying, but when this drying
+occurs the interior is commonly checked along the medullary rays,
+commonly called "honeycombing" or "hollow-horning." In practice this
+occurrence can be prevented by steaming or sweating the wood in the
+kiln, and still better by drying the wood in the open air or in a shed
+before placing in the kiln. Since only the first shrinkage is apt to
+check the wood, any kind of lumber which has once been air-dried
+(three to six months for one-inch stuff) may be subjected to kiln heat
+without any danger from this source.
+
+Kept in a bent or warped condition during the first shrinkage, the
+wood retains the shape to which it has been bent and firmly opposes
+any attempt at subsequent straightening.
+
+Sapwood, as a rule, shrinks more than heartwood of the same weight,
+but very heavy heartwood may shrink more than lighter sapwood. The
+amount of water in wood is no criterion of its shrinkage, since in wet
+wood most of the water is held in the cavities, where it has no effect
+on the volume.
+
+The wood of pine, spruce, cypress, etc., with its very regular
+structure, dries and shrinks evenly, and suffers much less in
+seasoning than the wood of broad-leaved (hardwood) trees. Among the
+latter, oak is the most difficult to dry without injury.
+
+Desiccating the air with certain chemicals will cause the wood to dry,
+but wood thus dried at 80 degrees Fahrenheit will still lose water in
+the kiln. Wood dried at 120 degrees Fahrenheit loses water still if
+dried at 200 degrees Fahrenheit, and this again will lose more water
+if the temperature be raised, so that _absolutely dry wood_ cannot be
+obtained, and chemical destruction sets in before all the water is
+driven off.
+
+On removal from the kiln, the dry wood at once takes up moisture from
+the air, even in the driest weather. At first the absorption is quite
+rapid; at the end of a week a short piece of pine, 1-1/2 inches thick,
+has regained two thirds of, and, in a few months, all the moisture
+which it had when air-dry, 8 to 10 per cent, and also its former
+dimensions. In thin boards all parts soon attain the same degree of
+dryness. In heavy timbers the interior remains more moist for many
+months, and even years, than the exterior parts. Finally an
+equilibrium is reached, and then only the outer parts change with the
+weather.
+
+With kiln-dried woods all parts are equally dry, and when exposed, the
+moisture coming from the air must pass through the outer parts, and
+thus the order is reversed. Ordinary timber requires months before it
+is at its best. Kiln-dried timber, if properly handled, is prime at
+once.
+
+Dry wood if soaked in water soon regains its original volume, and in
+the heartwood portion it may even surpass it; that is to say, swell to
+a larger dimension than it had when green. With the soaking it
+continues to increase in weight, the cell cavities filling with water,
+and if left many months all pieces sink. Yet after a year's immersion
+a piece of oak 2 by 2 inches and only 6 inches long still contains
+air; _i.e._, it has not taken up all the water it can. By rafting or
+prolonged immersion, wood loses some of its weight, soluble materials
+being leached out, but it is not impaired either as fuel or as
+building material. Immersion, and still more boiling and steaming,
+reduce the hygroscopicity of wood and therefore also the troublesome
+"working," or shrinking and swelling.
+
+Exposure in dry air to a temperature of 300 degrees Fahrenheit for a
+short time reduces but does not destroy the hygroscopicity, and with
+it the tendency to shrink and swell. A piece of red oak which has been
+subjected to a temperature of over 300 degrees Fahrenheit still swells
+in hot water and shrinks in a dry kiln.
+
+
+                           Expansion of Wood
+
+It must not be forgotten that timber, in common with every other
+material, expands as well as contracts. If we extract the moisture
+from a piece of wood and so cause it to shrink, it may be swelled to
+its original volume by soaking it in water, but owing to the
+protection given to most timber in dwelling-houses it is not much
+affected by wet or damp weather. The shrinkage is more apparent, more
+lasting, and of more consequence to the architect, builder, or owner
+than the slight expansion which takes place, as, although the amount
+of moisture contained in wood varies with the climate conditions, the
+consequence of dampness or moisture on good timber used in houses only
+makes itself apparent by the occasional jamming of a door or window in
+wet or damp weather.
+
+Considerable expansion, however, takes place in the wood-paving of
+streets, and when this form of paving was in its infancy much trouble
+occurred owing to all allowances not having been made for this
+contingency, the trouble being doubtless increased owing to the blocks
+not being properly seasoned; curbing was lifted or pushed out of line
+and gully grids were broken by this action. As a rule in street paving
+a space of one or two inches wide is now left next to the curb, which
+is filled with sand or some soft material, so that the blocks may
+expand longitudinally without injuring the contour or affecting the
+curbs. But even with this arrangement it is not at all unusual for an
+inch or more to have to be cut off paving blocks parallel to the
+channels some time after the paving has been laid, owing to the
+expansion of the wood exceeding the amounts allowed.
+
+Considerable variation occurs in the expansion of wood blocks, and it
+is noticeable in the hardwoods as well as in the softwoods, and is
+often greater in the former than in the latter.
+
+Expansion takes place in the direction of the length of the blocks as
+they are laid across the street, and causes no trouble in the other
+direction, the reason being that the lengthway of a block of wood is
+across the grain, of the timber, and it expands or contracts as a
+plank does. On one occasion, in a roadway forty feet wide, expansion
+occurred until it amounted to four inches on each side, or eight
+inches in all. This continual expansion and contraction is doubtless
+the cause of a considerable amount of wood street-paving bulging and
+becoming filled with ridges and depressions.
+
+
+                    Elimination of Stain and Mildew
+
+A great many manufacturers, and particularly those located in the
+Southern States, experience a great amount of difficulty in their
+timber becoming stained and mildewed. This is particularly true with
+gum wood, as it will frequently stain and mould in twenty-four hours,
+and they have experienced so much of this trouble that they have, in a
+great many instances, discontinued cutting it during the summer
+season.
+
+If this matter were given proper attention they should be able to
+eliminate a great deal of this difficulty, as no doubt they will find
+after investigation that the mould has been caused by the stock being
+improperly piled to the weather.
+
+Freshly sawn wood, placed in close piles during warm, damp weather in
+the months of July and August, presents especially favorable
+conditions for mould and stain. In all cases it is the moist condition
+and retarded drying of the wood which causes this. Therefore, any
+method which will provide for the rapid drying of the wood before or
+after piling will tend to prevent the difficulty, and the best method
+for eliminating mould is (1) to provide for as little delay as
+possible between the felling of the tree, and its manufacture into
+rough products before the sap has had an opportunity of becoming sour.
+This is especially necessary with trees felled from April to
+September, in the region north of the Gulf States, and from March to
+November in the latter, while the late fall and winter cutting should
+all be worked up by March or April. (2) The material should be piled
+to the weather immediately after being sawn or cut, and every
+precaution should be taken in piling to facilitate rapid drying, by
+keeping the piles or ricks up off the ground. (3) All weeds (and
+emphasis should be placed on the ALL) and other vegetation should be
+kept well clear of the piles, in order that the air may have a clear
+and unobstructed passage through and around the piles, and (4) the
+piles should be so constructed that each stick or piece will have as
+much air space about it as it is possible to give to it.
+
+If the above instructions are properly carried out, there will be
+little or no difficulty experienced with mould appearing on the
+lumber.
+
+
+
+
+                              SECTION IX
+
+                      DIFFICULTIES OF DRYING WOOD
+
+
+Seasoning and kiln-drying is so important a process in the manufacture
+of woods that a need is keenly felt for fuller information regarding
+it, based upon scientific study of the behavior of various species at
+different mechanical temperatures and under different mechanical
+drying processes. The special precautions necessary to prevent loss of
+strength or distortion of shape render the drying of wood especially
+difficult.
+
+All wood when undergoing a seasoning process, either natural (by air)
+or mechanical (by steam or heat in a dry kiln), checks or splits more
+or less. This is due to the uneven drying-out of the wood and the
+consequent strains exerted in opposite directions by the wood fibres
+in shrinking. This shrinkage, it has been proven, takes place both
+end-wise and across the grain of the wood. The old tradition that wood
+does not shrink end-wise has long since been shattered, and it has
+long been demonstrated that there is an end-wise shrinkage.
+
+In some woods it is very light, while in others it is easily
+perceptible. It is claimed that the average end shrinkage, taking all
+the woods, is only about 1-1/2 per cent. This, however, probably has
+relation to the average shrinkage on ordinary lumber as it is used and
+cut and dried. Now if we depart from this and take veneer, or basket
+stock, or even stave bolts where they are boiled, causing swelling
+both end-wise and across the grain or in dimension, after they are
+thoroughly dried, there is considerably more evidence of end
+shrinkage. In other words, a slack barrel stave of elm, say, 28 or 30
+inches in length, after being boiled might shrink as much in
+thoroughly drying-out as compared to its length when freshly cut, as a
+12-foot elm board.
+
+It is in cutting veneer that this end shrinkage becomes most readily
+apparent. In trimming with scoring knives it is done to exact measure,
+and where stock is cut to fit some specific place there has been
+observed a shrinkage on some of the softer woods, like cottonwood,
+amounting to fully 1/8 of an inch in 36 inches. And at times where
+drying has been thorough the writer has noted a shrinkage of 1/8 of an
+inch on an ordinary elm cabbage-crate strip 36 inches long, sawed from
+the log without boiling.
+
+There are really no fixed rules of measurement or allowance, however,
+because the same piece of wood may vary under different conditions,
+and, again, the grain may cross a little or wind around the tree, and
+this of itself has a decided effect on the amount of what is termed
+"end shrinkage."
+
+There is more checking in the wood of the broad-leaf (hardwood) trees
+than in that of the coniferous (softwood) trees, more in sapwood than
+in heartwood, and more in summer-wood than in spring-wood.
+
+Inasmuch as under normal conditions of weather, water evaporates less
+rapidly during the early seasoning of winter, wood that is cut in the
+autumn and early winter is considered less subject to checking than
+that which is cut in spring and summer.
+
+Rapid seasoning, except after wood has been thoroughly soaked or
+steamed, almost invariably results in more or less serious checking.
+All hardwoods which check or warp badly during the seasoning should be
+reduced to the smallest practicable size before drying to avoid the
+injuries involved in this process, and wood once seasoned _should
+never again be exposed to the weather_, since all injuries due to
+seasoning are thereby aggravated.
+
+Seasoning increases the strength of wood in every respect, and it is
+therefore of great importance to protect the wood against moisture.
+
+
+                  Changes rendering Drying difficult
+
+An important property rendering drying of wood peculiarly difficult is
+the changes which occur in the hygroscopic properties of the surface
+of a stick, and the rate at which it will allow moisture to pass
+through it. If wood is dried rapidly the surface soon reaches a
+condition where the transfusion is greatly hindered and sometimes
+appears almost to cease. The nature of this action is not well
+understood and it differs greatly in different species. Bald cypress
+(_Taxodium distichum_) is an example in which this property is
+particularly troublesome. The difficulty can be overcome by regulating
+the humidity during the drying operation. It is one of the factors
+entering into production of what is called "case-hardening" of wood,
+where the surface of the piece becomes hardened in a stretched or
+expanded condition, and subsequent shrinkage of the interior causes
+"honeycombing," "hollow-horning," or internal checking. The outer
+surface of the wood appears to undergo a chemical change in the nature
+of hydrolization or oxidization, which alters the rate of absorption
+and evaporation in the air.
+
+As the total amount of shrinkage varies with the rate at which the
+wood is dried, it follows that the outer surface of a rapidly dried
+board shrinks less than the interior. This sets up an internal stress,
+which, if the board be afterward resawed into two thinner boards by
+slicing it through the middle, causes the two halves to cup with their
+convex surfaces outward. This effect may occur even though the
+moisture distribution in the board has reached a uniform condition,
+and the board is thoroughly dry before it is resawed. It is distinct
+from the well-known "case-hardening" effect spoken of above, which is
+caused by unequal moisture conditions.
+
+The manner in which the water passes from the interior of a piece of
+wood to its surface has not as yet been fully determined, although it
+is one of the most important factors which influence drying. This must
+involve a transfusion of moisture through the cell walls, since, as
+already mentioned, except for the open vessels in the hardwoods, free
+resin ducts in the softwoods, and possibly the intercellular spaces,
+the cells of green wood are enclosed by membranes and the water must
+pass through the walls or the membranes of the pits. Heat appears to
+increase this transfusion, but experimental data are lacking.
+
+It is evident that to dry wood properly a great many factors must be
+taken into consideration aside from the mere evaporation of moisture.
+
+
+                  Losses Due to Improper Kiln-drying
+
+In some cases there is practically no loss in drying, but more often
+it ranges from 1 to 3 per cent, and 7 to 10 per cent in refractory
+woods such as gum. In exceptional instances the losses are as high as
+33 per cent.
+
+In air-drying there is little or no control over the process; it may
+take place too rapidly on some days and too slowly on others, and it
+may be very non-uniform.
+
+Hardwoods in large sizes almost invariably check.
+
+By proper kiln-drying these unfavorable circumstances may be
+eliminated. However, air-drying is unquestionably to be preferred to
+bad kiln-drying, and when there is any doubt in the case it is
+generally safer to trust to air-drying.
+
+If the fundamental principles are all taken care of, green lumber can
+be better dried in the dry kiln.
+
+
+                 Properties of Wood that affect Drying
+
+It is clear, from the previous discussion of the structure of wood,
+that this property is of first importance among those influencing the
+seasoning of wood. The free water way usually be extracted quite
+readily from porous hardwoods. The presence of tyloses in white oak
+makes even this a difficult problem. On the other hand, its more
+complex structure usually renders the hygroscopic moisture quite
+difficult to extract.
+
+The lack of an open, porous structure renders the transfusion of
+moisture through some woods very slow, while the reverse may be true
+of other species. The point of interest is that all the different
+variations in structure affect the drying rates of woods. The
+structure of the gums suggests relatively easy seasoning.
+
+Shrinkage is a very important factor affecting the drying of woods.
+Generally speaking, the greater the shrinkage the more difficult it is
+to dry wood. Wood shrinks about twice as much tangentially as
+radially, thus introducing very serious stresses which may cause loss
+in woods whose total shrinkage is large. It has been found that the
+amount of shrinkage depends, to some extent, on the rate and
+temperature at which woods season. Rapid drying at high or low
+temperature results in slight shrinkage, while slow drying, especially
+at high temperature, increases the shrinkage.
+
+As some woods must be dried in one way and others in other ways, to
+obtain the best general results, this effect may be for the best in
+one case and the reverse in others. As an example one might cite the
+case of Southern white oak. This species must be dried very slowly at
+low temperatures in order to avoid the many evils to which it is heir.
+It is interesting to note that this method tends to increase the
+shrinkage, so that one might logically expect such treatment merely to
+aggravate the evils. Such is not the case, however, as too fast drying
+results in other defects much worse than that of excessive shrinkage.
+
+Thus we see that the shrinkage of any given species of wood depends to
+a great extent on the method of drying. Just how much the shrinkage of
+gum is affected by the temperature and drying rate is not known at
+present. There is no doubt that the method of seasoning affects the
+shrinkage of the gums, however. It is just possible that these woods
+may shrink longitudinally more than is normal, thus furnishing another
+cause for their peculiar action under certain circumstances. It has
+been found that the properties of wood which affect the seasoning of
+the gums are, in the order of their importance: (1) The indeterminate
+and erratic grain; (2) the uneven shrinkage with the resultant
+opposing stresses; (3) the plasticity under high temperature while
+moist; and (4) the slight apparent lack of cohesion between the
+fibres. The first, second, and fourth properties are clearly
+detrimental, while the third may possibly be an advantage in reducing
+checking and "case-hardening."
+
+The grain of the wood is a prominent factor also affecting the
+problem. It is this factor, coupled with uneven shrinkage, which is
+probably responsible, to a large extent, for the action of the gums in
+drying. The grain may be said to be more or less indeterminate. It is
+usually spiral, and the spiral may reverse from year to year of the
+tree's growth. When a board in which this condition exists begins to
+shrink, the result is the development of opposing stresses, the effect
+of which is sometimes disastrous. The shrinkage around the knots seems
+to be particularly uneven, so that checking at the knots is quite
+common.
+
+Some woods, such as Western red cedar, redwood, and eucalyptus, become
+very plastic when hot and moist. The result of drying-out the free
+water at high temperature may be to collapse the cells. The gums are
+known to be quite soft and plastic, if they are moist, at high
+temperature, but they do not collapse so far as we have been able to
+determine.
+
+The cells of certain species of wood appear to lack cohesion,
+especially at the junction between the annual rings. As a result,
+checks and ring shakes are very common in Western larch and hemlock.
+The parenchyma cells of the medullary rays in oak do not cohere
+strongly and often check open, especially when steamed too severely.
+
+
+                   Unsolved Problems in Kiln-drying
+
+     1. Physical data of the properties of wood in relation to
+     heat are meagre.
+
+     2. Figures on the specific heat of wood are not readily
+     available, though upon this rests not only the exact
+     operation of heating coils for kilns, but the theory of
+     kiln-drying as a whole.
+
+     3. Great divergence is shown in the results of experiments
+     in the conductivity of wood. It remains to be seen whether
+     the known variation of conductivity with moisture content
+     will reduce these results to uniformity.
+
+     4. The maximum or highest temperature to which the different
+     species of wood may be exposed without serious loss of
+     strength has not yet been determined.
+
+     5. The optimum or absolute correct temperature for drying
+     the different species of wood is as yet entirely unsettled.
+
+     6. The inter-relation between wood and water is as
+     imperfectly known to dry-kiln operators as that between wood
+     and heat.
+
+     7. What moisture conditions obtain in a stick of air-dried
+     wood?
+
+     8. How is the moisture distinguished?
+
+     9. What is its form?
+
+     10. What is the meaning of the peculiar surface conditions
+     which even in air-dried wood appear to indicate incipient
+     "case-hardening"?
+
+     11. The manner in which the water passes from the interior
+     of a piece of wood to its surface has not as yet been fully
+     determined.
+
+These questions can be answered thus far only by speculation or, at
+best, on the basis of incomplete data.
+
+Until these problems are solved, kiln-drying must necessarily remain
+without the guidance of complete scientific theory.
+
+A correct understanding of the principles of drying is rare, and
+opinions in regard to the subject are very diverse. The same lack of
+knowledge exists in regard to dry kilns. The physical properties of
+the wood which complicate the drying operation and render it distinct
+from that of merely evaporating free water from some substance like a
+piece of cloth must be studied experimentally. It cannot well be
+worked out theoretically.
+
+
+
+
+                               SECTION X
+
+                         HOW WOOD IS SEASONED
+
+
+                           Methods of Drying
+
+The choice of a method of drying depends largely upon the object in
+view. The principal objects may be grouped under three main heads, as
+follows:
+
+     1. To reduce shipping weight.
+
+     2. To reduce the quantity necessary to carry in stock.
+
+     3. To prepare the wood for its ultimate use and improve its
+     qualities.
+
+When wood will stand the temperature without excessive checking or
+undue shrinkage or loss in strength, the first object is most readily
+attained by heating the wood above the boiling point in a closed
+chamber, with a large circulation of air or vapor, so arranged that
+the excess steam produced will escape. This process manifestly does
+not apply to many of the hardwoods, but is applicable to many of the
+softwoods. It is used especially in the northwestern part of the
+United States, where Douglas fir boards one inch thick are dried in
+from 40 to 65 hours, and sometimes in as short a time as 24 hours. In
+the latter case superheated steam at 300 degrees Fahrenheit was forced
+into the chamber but, of course, the lumber could not be heated
+thereby much above the boiling point so long as it contained any free
+water.
+
+This lumber, however, contained but 34 per cent moisture to start
+with, and the most rapid rate was 1.6 per cent loss per hour.
+
+The heat of evaporation may be supplied either by superheated steam or
+by steam pipes within the kiln itself.
+
+The quantity of wood it is necessary to carry in stock is naturally
+reduced when either of the other two objects is attained and,
+therefore, need not necessarily be discussed.
+
+In drying to prepare for use and to improve quality, careful and
+scientific drying is called for. This applies more particularly to the
+hardwoods, although it may be required for softwoods also.
+
+
+                    Drying at Atmospheric Pressure
+
+Present practice of kiln-drying varies tremendously and there is no
+uniformity or standard method.
+
+Temperatures vary anywhere from 65 to 165 degrees Fahrenheit, or even
+higher, and inch boards three to six months on the sticks are being
+dried in from four days to three weeks, and three-inch material in
+from two to five months.
+
+All methods in use at atmospheric pressure may be classified under the
+following headings. The kilns may be either progressive or
+compartment, and preliminary steaming may or may not be used with any
+one of these methods:
+
+     1. Dry air heated. This is generally obsolete.
+     2. Moist air.
+         _a._ Ventilated.
+         _b._ Forced draft.
+         _c._ Condensing.
+         _d._ Humidity regulated.
+         _e._ Boiling.
+     3. Superheated steam.
+
+
+                   Drying under Pressure and Vacuum
+
+Various methods of drying wood under pressures other than atmospheric
+have been tried. Only a brief mention of this subject will be made.
+Where the apparatus is available probably the quickest way to dry wood
+is first to heat it in saturated steam at as high a temperature as the
+species can endure without serious chemical change until the heat has
+penetrated to the center, then follow this with a vacuum.
+
+By this means the self-contained specific heat of the wood and the
+water is made available for the evaporation, and the drying takes
+place from the inside outwardly, just the reverse of that which occurs
+by drying by means of external heat.
+
+When the specimen has cooled this process is then to be repeated until
+it has dried down to fibre-saturation point. It cannot be dried much
+below this point by this method, since the absorption during the
+heating operation will then equal the evaporation during the cooling.
+It may be carried further, however, by heating in partially humidified
+air, proportioning the relative humidity each time it is heated to the
+degree of moisture present in the wood.
+
+The point to be considered in this operation is that during the
+heating process no evaporation shall be allowed to take place, but
+only during the cooling. In this way surface drying and
+"case-hardening" are prevented since the heat is from within and the
+moisture passes from the inside outwardly. However, with some species,
+notably oak, surface cracks appear as a network of fine checks along
+the medullary rays.
+
+In the first place, it should be borne in mind that it is the heat
+which produces evaporation and not the air nor any mysterious property
+assigned to a "vacuum."
+
+For every pound of water evaporated at ordinary temperatures
+approximately 1,000 British thermal units of heat are used up, or
+"become latent," as it is called. This is true whether the evaporation
+takes place in a vacuum or under a moderate air pressure. If this heat
+is not supplied from an outside source it must be supplied by the
+water itself (or the material being dried), the temperature of which
+will consequently fall until the surrounding space becomes saturated
+with vapor at a pressure corresponding to the temperature which the
+water has reached; evaporation will then cease. The pressure of the
+vapor in a space saturated with water vapor increases rapidly with
+increase of temperature. At a so-called vacuum of 28 inches, which is
+about the limit in commercial operations, and in reality signifies an
+actual pressure of 2 inches of mercury column, the space will be
+saturated with vapor at 101 degrees Fahrenheit. Consequently, no
+evaporation will take place in such a vacuum unless the water be
+warmer than 101 degrees Fahrenheit, provided there is no air leakage.
+The qualification in regard to air is necessary, for the sake of
+exactness, for the following reason: In any given space the total
+actual pressure is made up of the combined pressures of all the gases
+present. If the total pressure ("vacuum") is 2 inches, and there is no
+air present, it is all produced by the water vapor (which saturates
+the space at 101 degrees Fahrenheit); but if some air is present and
+the total pressure is still maintained at 2 inches, then there must be
+less vapor present, since the air is producing part of the pressure
+and the space is no longer saturated at the given temperature.
+Consequently further evaporation may occur, with a corresponding
+lowering of the temperature of the water, until a balance is again
+reached. Without further explanation it is easy to see that but little
+water can be evaporated by a vacuum alone without addition of heat,
+and that the prevalent idea that a vacuum can of itself produce
+evaporation is a fallacy. If heat be supplied to the water, however,
+either by conduction or radiation, evaporation will take place in
+direct proportion to the amount of heat supplied, so long as the
+pressure is kept down by the vacuum pump.
+
+At 30 inches of mercury pressure (one atmosphere) the space becomes
+saturated with vapor and equilibrium is established at 212 degrees
+Fahrenheit. If heat be now supplied to the water, however, evaporation
+will take place in proportion to the amount of heat supplied, so long
+as the pressure remains that of one atmosphere, just as in the case of
+the vacuum. Evaporation in this condition, where the vapor pressure at
+the temperature of the water is equal to the gas pressure on the
+water, is commonly called "boiling," and the saturated vapor entirely
+displaces the air under continuous operation. Whenever the space is
+not saturated with vapor, whether air is present or not, evaporation
+will take place, by boiling if no air be present or by diffusion under
+the presence of air, until an equilibrium between temperature and
+vapor pressure is resumed.
+
+Relative humidity is simply the ratio of the actual vapor pressure
+present in a given space to the vapor pressure when the space is
+saturated with vapor at the given temperature. It matters not whether
+air be present or not. One hundred per cent humidity means that the
+space contains all the vapor which it can hold at the given
+temperature--it is saturated. Thus at 100 per cent humidity and 212
+degrees Fahrenheit the space is saturated, and since the pressure of
+saturated vapor at this temperature is one atmosphere, no air can be
+present under these conditions. If, however, the total pressure at
+this temperature were 20 pounds (5 pounds gauge), then it would mean
+that there was 5 pounds air pressure present in addition to the vapor,
+yet the space would still be saturated at the given temperature.
+Again, if the temperature were 101 degrees Fahrenheit, the pressure of
+saturated vapor would be only 1 pound, and the additional pressure of
+14 pounds, if the total pressure were atmospheric, would be made up of
+air. In order to have no air present and the space still saturated at
+101 degrees Fahrenheit, the total pressure must be reduced to 1 pound
+by a vacuum pump. Fifty per cent relative humidity, therefore,
+signifies that only half the amount of vapor required to saturate the
+space at the given temperature is present. Thus at 212 degrees
+Fahrenheit temperature the vapor pressure would only be 7-1/2 pounds
+(vacuum of 15 inches gauge). If the total pressure were atmospheric,
+then the additional 7-1/2 pounds would be simply air.
+
+"Live steam" is simply water-saturated vapor at a pressure usually
+above atmospheric. We may just as truly have live steam at pressures
+less than atmospheric, at a vacuum of 28 inches for instance. Only in
+the latter case its temperature would be lower, _viz._, 101 degrees
+Fahrenheit.
+
+Superheated steam is nothing more than water vapor at a relative
+humidity less than saturation, but is usually considered at pressures
+above atmospheric, and in the absence of air. The atmosphere at, say,
+50 per cent relative humidity really contains superheated steam or
+vapor, the only difference being that it is at a lower temperature and
+pressure than we are accustomed to think of in speaking of superheated
+steam, and it has air mixed with it to make up the deficiency in
+pressure below the atmosphere.
+
+Two things should now be clear; that evaporation is produced by heat
+and that the presence or absence of air does not influence the amount
+of evaporation. It does, however, influence the rate of evaporation,
+which is retarded by the presence of air. The main things influencing
+evaporation are, first, the quantity of heat supplied and, second, the
+relative humidity of the immediately surrounding space.
+
+
+                      Drying by Superheated Steam
+
+What this term really signifies is simply water vapor in the absence
+of air in a condition of less than saturation. Kilns of this type are,
+properly speaking, vapor kilns, and usually operate at atmospheric
+pressure, but may be used at greater pressures or at less pressures.
+As stated before, the vapor present in the air at any humidity less
+than saturation is really "superheated steam," only at a lower
+pressure than is ordinarily understood by this term, and mixed with
+air. The main argument in favor of this process seems to be based on
+the idea that steam is moist heat. This is true, however, only when
+the steam is near saturation. When it is superheated it is just as dry
+as air containing the same relative humidity. For instance, steam at
+atmospheric pressure and heated to 248 degrees Fahrenheit has a
+relative humidity of only 50 per cent and is just as dry as air
+containing the same humidity. If heated to 306 degrees Fahrenheit, its
+relative humidity is reduced to 20 per cent; that is to say, the ratio
+of its actual vapor pressure (one atmosphere) to the pressure of
+saturated vapor at this temperature (five atmospheres) is 1:5, or 20
+per cent. Superheated vapor in the absence of air, however, parts with
+its heat with great rapidity and finally becomes saturated when it has
+lost all of its ability to cause evaporation. In this respect it is
+more moist than air when it comes in contact with bodies which are at
+a lower temperature. When saturated steam is used to heat the lumber
+it can raise the temperature of the latter to its own temperature, but
+cannot produce evaporation unless, indeed, the pressure is varied.
+Only by the heat supplied above the temperature of saturation can
+evaporation be produced.
+
+
+                         Impregnation Methods
+
+Methods of partially overcoming the shrinkage by impregnation of the
+cell walls with organic materials closely allied to the wood substance
+itself are in use. In one of these which has been patented, sugar is
+used as the impregnating material, which is subsequently hardened or
+"caramelized" by heating. Experiments which the United States Forest
+Service has made substantiate the claims that the sugar does greatly
+reduce the shrinkage of the wood; but the use of impregnation
+processes is determined rather from a financial economic standpoint
+than by the physical result obtained.
+
+Another process consists in passing a current of electricity through
+the wet boards or through the green logs before sawing. It is said
+that the ligno cellulose and the sap are thus transformed by
+electrolysis, and that the wood subsequently dries more rapidly.
+
+
+                        Preliminary Treatments
+
+In many dry kiln operations, especially where the kilns are not
+designed for treatments with very moist air, the wood is allowed to
+air-season from several months to a year or more before running it
+into the dry kiln. In this way the surface dries below its
+fibre-saturation point and becomes hardened or "set" and the
+subsequent shrinkage is not so great. Moreover, there is less danger
+of surface checking in the kiln, since the surface has already passed
+the danger point. Many woods, however, check severely in air-drying or
+case-harden in the air. It is thought that such woods can be
+satisfactorily handled in a humidity-regulated kiln direct from the
+saw.
+
+Preliminary steaming is frequently used to moisten the surface if
+case-hardened, and to heat the lumber through to the center before
+drying begins. This is sometimes done in a separate chamber, but more
+often in a compartment of the kiln itself, partitioned off by means of
+a curtain which can be raised or lowered as circumstances require.
+This steaming is usually conducted at atmospheric pressure and
+frequently condensed steam is used at temperatures far below 212
+degrees Fahrenheit. In a humidity-regulated kiln this preliminary
+treatment may be omitted, since nearly saturated conditions can be
+maintained and graduated as the drying progresses.
+
+Recently the process of steaming at pressures up to 20 pounds gauge in
+a cylinder for short periods of time, varying from 5 to 20 minutes, is
+being advocated in the United States. The truck load is run into the
+cylinder, steamed, and then taken directly out into the air. It may
+subsequently be placed in the dry kiln if further drying is desired.
+The self-contained heat of the wood evaporates considerable moisture,
+and the sudden drying of the boards causes the shrinkage to be reduced
+slightly in some cases. Such short periods of steaming under 20 pounds
+pressure do not appear to injure the wood mechanically, although they
+do darken the color appreciably, especially of the sapwood of the
+species having a light-colored sap, as black walnut (_Juglans nigra_)
+and red gum (_Liquidamber styraciflua_). Longer periods of steaming
+have been found to weaken the wood. There is a great difference in the
+effect on different species, however.
+
+Soaking wood for a long time before drying has been practised, but
+experiments indicate that no particularly beneficial results, from the
+drying standpoint, are attained thereby. In fact, in some species
+containing sugars and allied substances it is probably detrimental
+from the shrinkage standpoint. If soaked in boiling water some species
+shrink and warp more than if dried without this treatment.
+
+In general, it may be said that, except possibly for short-period
+steaming as described above, steaming and soaking hardwoods at
+temperatures of 212 degrees Fahrenheit or over should be avoided if
+possible.
+
+It is the old saying that wood put into water shortly after it is
+felled, and left in water for a year or more, will be perfectly
+seasoned after a short subsequent exposure to the air. For this reason
+rivermen maintain that timber is made better by rafting. Herzenstein
+says: "Floating the timber down rivers helps to wash out the sap, and
+hence must be considered as favorable to its preservation, the more so
+as it enables it to absorb more preservative."
+
+Wood which has been buried in swamps is eagerly sought after by
+carpenters and joiners, because it has lost all tendency to warp and
+twist. When first taken from the swamp the long-immersed logs are very
+much heavier than water, but they dry with great rapidity. A cypress
+log from the Mississippi Delta, which two men could barely handle at
+the time it was taken out some years ago, has dried out so much since
+then that to-day one man can lift it with ease. White cedar telegraph
+poles are said to remain floating in the water of the Great Lakes
+sometimes for several years before they are set in lines and to last
+better than freshly cut poles.
+
+It is very probable that immersion for long periods in water does
+materially hasten subsequent seasoning. The tannins, resins,
+albuminous materials, etc., which are deposited in the cell walls of
+the fibres of green wood, and which prevent rapid evaporation of the
+water, undergo changes when under water, probably due to the action of
+bacteria which live without air, and in the course of time many of
+these substances are leached out of the wood. The cells thereby become
+more and more permeable to water, and when the wood is finally brought
+into the air the water escapes very rapidly and very evenly.
+Herzenstein's statement that wood prepared by immersion and subsequent
+drying will absorb more preservative, and that with greater rapidity,
+is certainly borne out by experience in the United States.
+
+It is sometimes claimed that all seasoning preparatory to treatment
+with a substance like tar oil might be done away with by putting the
+green wood into a cylinder with the oil and heating to 225 degrees
+Fahrenheit, thus driving the water off in the form of steam, after
+which the tar oil would readily penetrate into the wood. This is the
+basis of the so-called "Curtiss process" of timber treatment. Without
+going into any discussion of this method of creosoting, it may be said
+that the same objection made for steaming holds here. In order to get
+a temperature of 212 degrees Fahrenheit in the center of the treated
+wood, the outside temperature would have to be raised so high that the
+strength of the wood might be seriously injured.
+
+A company on the Pacific coast which treats red fir piling asserts
+that it avoids this danger by leaving the green timber in the tar oil
+at a temperature which never exceeds 225 degrees Fahrenheit for from
+five to twelve hours, until there is no further evidence of water
+vapor coming out of the wood. The tar oil is then run out, and a
+vacuum is created for about an hour, after which the oil is run in
+again and is kept in the cylinders under 100 pounds pressure for from
+ten to twelve hours, until the required amount of absorption has been
+reached (about 12 pounds per cubic foot).
+
+
+                         Out-of-door Seasoning
+
+The most effective seasoning is without doubt that obtained by the
+uniform, slow drying which takes place in properly constructed piles
+outdoors, under exposure to the winds and the sun. Lumber has always
+been seasoned in this way, which is still the best for ordinary
+purposes.
+
+It is probable for the sake of economy, air-drying will be eliminated
+in the drying process of the future without loss to the quality of the
+product, but as yet no effective method has been discovered whereby
+this may be accomplished, because nature performs certain functions in
+air-drying that cannot be duplicated by artificial means. Because of
+this, hardwoods, as a rule, cannot be successfully kiln-dried green or
+direct from the saw, and must receive a certain amount of preliminary
+air-drying before being placed in a dry kiln.
+
+The present methods of air-seasoning in use have been determined by
+long experience, and are probably as good as they could be made for
+present conditions. But the same care has not up to this time been
+given to the seasoning of such timber as ties, bridge material, posts,
+telegraph and telephone poles, etc. These have sometimes been piled
+more or less intelligently, but in the majority of cases their value
+has been too low to make it seem worth while to pile with reference to
+anything beyond convenience in handling.
+
+In piling material for air-seasoning, one should utilize high, dry
+ground when possible, and see that the foundations are high enough off
+the ground, so that there is proper air circulation through the bottom
+of the piles, and also that the piles are far enough apart so that the
+air may circulate freely through and around them.
+
+It is air circulation that is desired in all cases of drying, both in
+dry kilns and out-of-doors, and not sunshine; that is, not the sun
+shining directly upon the material. The ends also should be protected
+from the sun, and everything possible done to induce a free
+circulation of air, and to keep the foundations free from all plant
+growth.
+
+Naturally, the heavier the material to be dried, the more difficulty
+is experienced from checking, which has its most active time in the
+spring when the sap is rising. In fact the main period of danger in
+material checking comes with the March winds and the April showers,
+and not infrequently in the South it occurs earlier than that. In
+other words, as soon as the sap begins to rise, the timber shows signs
+of checking, and that is the time to take extra precautions by careful
+piling and protection from the sun. When the hot days of summer arrive
+the tendency to check is not so bad, but stock will sour from the
+heat, stain from the sap, mildew from moisture, and fall a prey to
+wood-destroying insects.
+
+It has been proven in a general way that wood will season more slowly
+in winter than in summer, and also that the water content during
+various months varies. In the spring the drying-out of wood cut in
+October and November will take place more rapidly.
+
+
+
+
+                              SECTION XI
+
+                          KILN-DRYING OF WOOD
+
+
+               Advantages of Kiln-drying over Air-drying
+
+Some of the advantages of kiln-drying to be secured over air-drying in
+addition to reducing the shipping weight and lessening quantity of
+stock are the following:
+
+     1. Less material lost.
+     2. Better quality of product.
+     3. Prevention of sap stain and mould.
+     4. Fixation of gums and resins.
+     5. Reduction of hygroscopicity.
+
+This reduction in the tendency to take up moisture means a reduction
+in the "working" of the material which, even though slight, is of
+importance.
+
+The problem of drying wood in the best manner divides itself into two
+distinct parts, one of which is entirely concerned with the behavior
+of the wood itself and the physical phenomena involved, while the
+other part has to do with the control of the drying process.
+
+
+           Physical Conditions governing the Drying of Wood
+
+     1. Wood is soft and plastic while hot and moist, and becomes
+     "set" in whatever shape it dries. Some species are much more
+     plastic than others.
+
+     2. Wood substance begins to shrink only when it dries below
+     the fibre-saturation point, at which it contains from 25 to
+     30 per cent moisture based on its dry weight. Eucalyptus and
+     certain other species appear to be exceptions to this law.
+
+     3. The shrinkage of wood is about twice as great
+     circumferentially as in the radial direction; lengthwise, it
+     is very slight.
+
+     4. Wood shrinks most when subjected, while kept moist, to
+     slow drying at high temperatures.
+
+     5. Rapid drying produces less shrinkage than slow drying at
+     high temperatures, but is apt to cause case-hardening and
+     honeycombing, especially in dense woods.
+
+     6. Case-hardening, honeycombing, and cupping result directly
+     from conditions 1, 4, and 5, and chemical changes of the
+     outer surface.
+
+     7. Brittleness is caused by carrying the drying process too
+     far, or by using too high temperatures. Safe limits of
+     treatment vary greatly for different species.
+
+     8. Wood absorbs or loses moisture in proportion to the
+     relative humidity in the air, not according to the
+     temperature. This property is called its "hygroscopicity."
+
+     9. Hygroscopicity and "working" are reduced but not
+     eliminated by thorough drying.
+
+     10. Moisture tends to transfuse from the hot towards the
+     cold portion of the wood.
+
+     11. Collapse of the cells may occur in some species while
+     the wood is hot and plastic. This collapse is independent of
+     subsequent shrinkage.
+
+
+                         Theory of Kiln-drying
+
+The dry kiln has long since acquired particular appreciation at the
+hands of those who have witnessed its time-saving qualities, when
+practically applied to the drying of timber. The science of drying is
+itself of the simplest, the exposure to the air being, indeed, the
+only means needed where the matter of time is not called into
+question. Otherwise, where hours, even minutes, have a marked
+significance, then other means must be introduced to bring about the
+desired effect. In any event, however, the same simple and natural
+remedy pertains,--the absorption of moisture. This moisture in green
+timber is known as "sap", which is itself composed of a number of
+ingredients, most important among which are water, resin, and albumen.
+
+All dry kilns in existence use heat to season timber; that is, to
+drive out that portion of the "sap" which is volatile.
+
+The heat does not drive out the resin of the pines nor the albumen of
+the hardwoods. It is really of no advantage in this respect. Resin in
+its hardened state as produced by heat is only slowly soluble in water
+and contains a large proportion of carbon, the most stable form of
+matter. Therefore, its retention in the pores of the wood is a
+positive advantage.
+
+To produce the ideal effect the drying must commence at the heart of
+the piece and work outward, the moisture being removed from the
+surface as fast as it exudes from the pores of the wood. To
+successfully accomplish this, adjustments must be available to
+regulate the temperature, circulation, and humidity according to the
+variations of the atmospheric conditions, the kind and condition of
+the material to be dried.
+
+This ideal effect is only attained by the use of a type of dry kiln in
+which the surface of the lumber is kept soft, the pores being left
+open until all the moisture within has been volatilized by the heat
+and carried off by a free circulation of air. When the moisture has
+been removed from the pores, the surface is dried without closing the
+pores, resulting in timber that is clean, soft, bright, straight, and
+absolutely free from stains, checks, or other imperfections.
+
+Now, no matter how the method of drying may be applied, it must be
+remembered that vapor exists in the atmosphere at all times, its
+volume being regulated by the capacity of the temperature absorbed. To
+kiln-dry properly, a free current of air must be maintained, of
+sufficient volume to carry off this moisture. Now, the capacity of
+this air for drying depends entirely upon the ability of its
+temperature to absorb or carry off a larger proportion of moisture
+than that apportioned by natural means. Thus, it will be seen, a cubic
+foot of air at 32 degrees Fahrenheit is capable of absorbing only two
+grains of water, while at 160 degrees, it will dispose of ninety
+grains. The air, therefore, should be made as dry as possible and
+caused to move freely, so as to remove all moisture from the surface
+of the wood as soon as it appears. Thus the heat effects a double
+purpose, not only increasing the rate of evaporation, but also the
+capacity of the air for absorption. Where these means are applied,
+which rely on the heat alone to accomplish this purpose, only that of
+the moisture which is volatile succumbs, while the albumen and resin
+becoming hardened under the treatment close up the pores of the wood.
+This latter result is oft-times accomplished while moisture yet
+remains and which in an enforced effort to escape bursts open the
+cells in which it has been confined and creates what is known as
+"checks."
+
+Therefore, taking the above facts into consideration, the essentials
+for the successful kiln-drying of wood may be enumerated as follows:
+
+     1. The evaporation from the surface of a stick should not
+     exceed the rate at which the moisture transfuses from the
+     interior to the surface.
+
+     2. Drying should proceed uniformly at all points, otherwise
+     extra stresses are set up in the wood, causing warping, etc.
+
+     3. Heat should penetrate to the interior of the piece before
+     drying begins.
+
+     4. The humidity should be suited to the condition of the
+     wood at the start and reduced in the proper ratio as drying
+     progresses. With wet or green wood it should usually be held
+     uniform at a degree which will prevent the surface from
+     drying below its saturation point until all the free water
+     has evaporated, then gradually reduced to remove the
+     hygroscopic moisture.
+
+     5. The temperature should be uniform and as high as the
+     species under treatment will stand without excessive
+     shrinkage, collapse, or checking.
+
+     6. Rate of drying should be controlled by the amount of
+     humidity in the air and not by the rate of circulation,
+     which should be made ample at all times.
+
+     7. In drying refractory hardwoods, such as oak, best results
+     are obtained at a comparatively low temperature. In more
+     easily dried hardwoods, such as maple, and some of the more
+     difficult softwoods, as cypress, the process may be hastened
+     by a higher temperature but not above the boiling point. In
+     many of the softwoods, the rate of drying may be very
+     greatly increased by heating above the boiling point with a
+     large circulation of vapor at atmospheric pressure.
+
+     8. Unequal shrinkage between the exterior and interior
+     portions of the wood and also unequal chemical changes must
+     be guarded against by temperatures and humidities suited to
+     the species in question to prevent subsequent cupping and
+     warping.
+
+     9. The degree of dryness attained should conform to the use
+     to which the wood is put.
+
+     10. Proper piling of the material and weighting to prevent
+     warping are of great importance.
+
+
+                Requirements in a Satisfactory Dry Kiln
+
+The requirements in a satisfactory dry kiln are:
+
+     1. Control of humidity at all times.
+     2. Ample air circulation at all points.
+     3. Uniform and proper temperatures.
+
+In order to meet these requirements the United States Forestry Service
+has designed a kiln in which the humidity, temperature, and
+circulation can be controlled at all times.
+
+Briefly, it consists of a drying chamber with a partition on either
+side, making two narrow side chambers open top and bottom.
+
+The steam pipes are in the usual position underneath the material to
+be dried.
+
+At the top of the side chambers is a spray; at the bottom are gutters
+and an eliminator or set of baffle plates to separate the fine mist
+from the air.
+
+The spray accomplishes two things: It induces an increased circulation
+and it regulates the humidity. This is done by regulating the
+temperature of the spray water.
+
+The air under the heating coil is saturated at whatever temperature
+is required. This temperature is the dew point of the air after it
+passes up into the drying chamber above the coils. Knowing the
+temperature in the drying room and the dew point, the relative
+humidity is thus determined.
+
+The relative humidity is simply the ratio of the vapor pressure at the
+dew point to the pressure of saturated vapor (see Fig. 30).
+
+    [Illustration: Fig. 30. Section through United States
+    Forestry Service Humidity-controlled Dry Kiln.]
+
+
+          Theory and Description of the Forestry Service Kiln
+
+The humidities and temperatures in the piles of lumber are largely
+dependent upon the circulation of air within the kiln. The temperature
+and humidity within the kiln, taken alone, are no criterion of the
+conditions of drying the pile of lumber if the circulation in any
+portion is deficient. It is possible to have an extremely rapid
+circulation of air within the dry kiln itself and yet have stagnation
+within the individual piles, the air passing chiefly through open
+spaces and channels. Wherever stagnation exists or the movement of air
+is too sluggish the temperature will drop and the humidity increase,
+perhaps to the point of saturation.
+
+When in large kilns the forced circulation is in the opposite
+direction from that induced by the cooling of the air by the lumber,
+there is always more or less uncertainty as to the movement of the air
+through the piles. Even with the boards placed edge-wise, with
+stickers running vertically, and with the heating pipes beneath the
+lumber, it was found that although the air passed upward through most
+of the spaces it was actually descending through others, so that very
+unequal drying resulted. While edge piling would at first thought seem
+ideal for the freest circulation in an ordinary kiln with steam pipes
+below, it in fact produces an indeterminate condition; air columns may
+pass downward through some channels as well as upward through others,
+and probably stagnate in still others. Nevertheless, edge piling is
+greatly superior to flat piling where the heating system is below the
+lumber.
+
+From experiments and from study of conditions in commercial kilns the
+idea was developed of so arranging the parts of the kiln and the pile
+of lumber that advantage might be taken of this cooling of the air to
+assist the circulation. That this can be readily accomplished without
+doing away with the present features of regulation of humidity by
+means of a spray of water is clear from Fig. 30, which shows a
+cross-section of the improved humidity-regulated dry kiln.
+
+In the form shown in the sketch a chamber or flue B runs through the
+center near the bottom. This flue is only about 6 or 7 feet in height
+and, together with the water spray F and the baffle plates DD,
+constitutes the humidity-control feature of the kiln. This control of
+humidity is affected by the temperature of the water used in the
+spray. This spray completely saturates the air in the flue B at
+whatever predetermined temperature is required. The baffle plates DD
+are to separate all entrained particles of water from the air, so that
+it is delivered to the heaters in a saturated condition at the
+required temperature. This temperature is, therefore, the dew point of
+the air when heated above, and the method of humidity control may
+therefore be called the dew-point method. It is a very simple matter
+by means of the humidity diagram (see Fig. 93), or by a hygrodeik
+(Fig. 94), to determine what dew-point temperature is needed for any
+desired humidity above the heaters.
+
+Besides regulating the humidity the spray F also acts as an ejector
+and forces circulation of air through the flue B. The heating system H
+is concentrated near the outer walls, so as to heat the rising column
+of air. The temperature within the drying chamber is controlled by
+means of any suitable thermostat, actuating a valve on the main steam
+line. The lumber is piled in such a way that the stickers slope
+downward toward the sides of the kiln.
+
+M is an auxiliary steam spray pointing downward for use at very high
+temperatures. C is a gutter to catch the precipitation and conduct it
+back to the pump, the water being recirculated through the sprays. G
+is a pipe condenser for use toward the end of the drying operation. K
+is a baffle plate for diverting the heated air and at the same time
+shielding the under layers of boards from direct radiation of the
+steam pipes.
+
+The operation of the kiln is simple. The heated air rises above the
+pipes HH and between the piles of lumber. As it comes in contact with
+the piles, portions of it are cooled and pass downward and outward
+through the layers of boards into the space between the condensers GG.
+Here the column of cooled air descends into the spray flue B, where
+its velocity is increased by the force of the water spray. It then
+passes out from the baffle plates to the heaters and repeats the
+cycle.
+
+One of the greatest advantages of this natural circulation method is
+that the colder the lumber when placed in the kiln the greater is the
+movement produced, under the very conditions which call for the
+greatest circulation--just the opposite of the direct-circulation
+method. This is a feature of the greatest importance in winter, when
+the lumber is put into the kiln in a frozen condition. One truckload
+of lumber at 60 per cent moisture may easily contain over 7,000 pounds
+of ice.
+
+In the matter of circulation the kiln is, in fact, seldom
+regulatory--the colder the lumber the greater the circulation
+produced, with the effect increased toward the cooler and wetter
+portions of the pile.
+
+Preliminary steaming may be used in connection with this kiln, but
+experiments indicate that ordinarily it is not desirable, since the
+high humidity which can be secured gives as good results, and being at
+as low a temperature as desired, much better results in the case of
+certain difficult woods like oak, eucalyptus, etc., are obtained.
+
+This kiln has another advantage in that its operation is entirely
+independent of outdoor atmospheric conditions, except that barometric
+pressure will effect it slightly.
+
+
+                              KILN-DRYING
+
+                                Remarks
+
+Drying is an essential part of the preparation of wood for
+manufacture. For a long time the only drying process used or known was
+air-drying, or the exposure of wood to the gradual drying influences
+of the open air, and is what has now been termed "preliminary
+seasoning." This method is without doubt the most successful and
+effective seasoning, because nature performs certain functions in
+air-drying that cannot be duplicated by artificial means. Because of
+this, hardwoods, as a rule, cannot be successfully kiln-dried green or
+direct from the saw.
+
+Within recent years, considerable interest is awakening among wood
+users in the operation of kiln-drying. The losses occasioned in
+air-drying and in improper kiln-drying, and the necessity for getting
+material dry as quickly as possible from the saw, for shipping
+purposes and also for manufacturing, are bringing about a realization
+of the importance of a technical knowledge of the subject.
+
+The losses which occur in air-drying wood, through checking, warping,
+staining, and rotting, are often greater than one would suppose. While
+correct statistics of this nature are difficult to obtain, some idea
+may be had of the amount of degrading of the better class of lumber.
+In the case of one species of soft wood, Western larch, it is commonly
+admitted that the best grades fall off sixty to seventy per cent in
+air-drying, and it is probable that the same is true in the case of
+Southern swamp oaks. In Western yellow pine, the loss is great, and in
+the Southern red gum, it is probably as much as thirty per cent. It
+may be said that in all species there is some loss in air-drying, but
+in some easily dried species such as spruce, hemlock, maple, etc., it
+is not so great.
+
+It would hardly be correct to state at the present time that this loss
+could be entirely prevented by proper methods of kiln-drying the green
+lumber, but it is safe to say that it can be greatly reduced.
+
+It is well where stock is kiln-dried direct from the saw or knife,
+after having first been steamed or boiled--as in the case of veneers,
+etc.,--to get them into the kiln while they are still warm, as they
+are then in good condition for kiln-drying, as the fibres of the wood
+are soft and the pores well opened, which will allow of forcing the
+evaporation of moisture without much damage being done to the
+material.
+
+With softwoods it is a common practice to kiln-dry direct from the
+saw. This procedure, however, is ill adapted for the hardwoods, in
+which it would produce such warping and checking as would greatly
+reduce the value of the product. Therefore, hardwoods, as a rule, are
+more or less thoroughly air-dried before being placed in the dry kiln,
+where the residue of moisture may be reduced to within three or four
+per cent, which is much lower than is possible by air-drying only.
+
+It is probable that for the sake of economy, air-drying will be
+eliminated in the drying processes of the future without loss to the
+quality of the product, but as yet no method has been discovered
+whereby this may be accomplished.
+
+The dry kiln has been, and probably still is, one of the most
+troublesome factors arising from the development of the timber
+industry. In the earlier days, before power machinery for the
+working-up of timber products came into general use, dry kilns were
+unheard-of, air-drying or seasoning was then relied upon solely to
+furnish the craftsman with dry stock from which to manufacture his
+product. Even after machinery had made rapid and startling strides on
+its way to perfection, the dry kiln remained practically an unknown
+quantity, but gradually, as the industry developed and demand for dry
+material increased, the necessity for some more rapid and positive
+method of seasoning became apparent, and the subject of artificial
+drying began to receive the serious attention of the more progressive
+and energetic members of the craft.
+
+Kiln-drying which is an artificial method, originated in the effort to
+improve or shorten the process, by subjecting the wood to a high
+temperature or to a draught of heated air in a confined space or kiln.
+In so doing, time is saved and a certain degree of control over the
+drying operation is secured.
+
+The first efforts in the way of artificial drying were confined to
+aiding or hastening nature in the seasoning process by exposing the
+material to the direct heat from fires built in pits, over which the
+lumber was piled in a way to expose it to the heat rays of the fires
+below. This, of course, was a primitive, hazardous, and very
+unsatisfactory method, to say the least, but it marked the first step
+in the evolution of the present-day dry kiln, and in that particular
+only is it deserving of mention.
+
+
+                         Underlying Principles
+
+In addition to marking the first step in artificial drying, it
+illustrated also, in the simplest manner possible, the three
+underlying principles governing all drying problems: (1) The
+application of heat to evaporate or volatilize the water contained in
+the material; (2) with sufficient air in circulation to carry away in
+suspension the vapor thus liberated; and (3) with a certain amount of
+humidity present to prevent the surface from drying too rapidly while
+the heat is allowed to penetrate to the interior. The last performs
+two distinct functions: (a) It makes the wood more permeable to the
+passage of the moisture from the interior of the wood to the surface,
+and (b) it supplies the latent heat necessary to evaporate the
+moisture after it reaches the surface. The air circulation is
+important in removing the moisture after it has been evaporated by the
+heat, and ventilation also serves the purpose of bringing the heat in
+contact with the wood. If, however, plain, dry heat is applied to the
+wood, the surface will become entirely dry before the interior
+moisture is even heated, let alone removed. This condition causes
+"case-hardening" or "hollow-horning." So it is very essential that
+sufficient humidity be maintained to prevent the surface from drying
+too rapidly, while the heat is allowed to penetrate to the interior.
+
+This humidity or moisture is originated by the evaporation from the
+drying wood, or by the admission of steam into the dry kiln by the use
+of steam spray pipes, and is absolutely necessary in the process of
+hastening the drying of wood. With green lumber it keeps the sap near
+the surface of the piece in a condition that allows the escape of the
+moisture from its interior; or, in other words, it prevents the
+outside from drying first, which would close the pores and cause
+case-hardening.
+
+The great amount of latent heat necessary to evaporate the water after
+it has reached the surface is shown by the fact that the evaporation
+of only one pound of water will extract approximately 66 degrees from
+1,000 cubic feet of air, allowing the air to drop in temperature from
+154 to 84 degrees Fahrenheit. In addition to this amount of heat, the
+wood and the water must also be raised to the temperature at which the
+drying is to be accomplished.
+
+It matters not what type of dry kiln is used, source or application of
+heating medium, these underlying principles remain the same, and must
+be the first things considered in the design or selection of the
+equipment necessary for producing the three essentials of drying:
+Heat, humidity, and circulation.
+
+Although these principles constitute the basis of all drying problems
+and must, therefore, be continually carried in mind in the
+consideration of them, it is equally necessary to have a comprehensive
+understanding of the characteristics of the materials to be dried, and
+its action during the drying process. All failures in the past, in the
+drying of timber products, can be directly attributed to either the
+kiln designer's neglect of these things, or his failure to carry them
+fully in mind in the consideration of his problems.
+
+Wood has characteristics very much different from those of other
+materials, and what little knowledge we have of it and its properties
+has been taken from the accumulated records of experience. The reason
+for this imperfect knowledge lies in the fact that wood is not a
+homogeneous material like the metals, but a complicated structure, and
+so variable that one stick will behave in a manner widely different
+from that of another, although it may have been cut from the same
+tree.
+
+The great variety of woods often makes the mere distinction of the
+kind or species of the tree most difficult. It is not uncommon to find
+men of long experience disagree as to the kind of tree a certain piece
+of lumber was cut from, and, in some cases, there is even a wide
+difference in the appearance and evidently the structure of timber cut
+from the same tree.
+
+
+                        Objects of Kiln-drying
+
+The objects of kiln-drying wood may be placed under three main
+headings: (1) To reduce shipping expenses; (2) to reduce the quantity
+necessary to maintain in stock; and (3) to reduce losses in air-drying
+and to properly prepare the wood for subsequent use. Item number 2
+naturally follows as a consequence of either 1 or 3. The reduction in
+weight on account of shipping expenses is of greatest significance
+with the Northwestern lumbermen in the case of Douglas fir, redwood,
+Western red cedar, sugar pine, bull pine, and other softwoods.
+
+Very rapid methods of rough drying are possible with some of these
+species, and are in use. High temperatures are used, and the water is
+sometimes boiled off from the wood by heating above 212 degrees
+Fahrenheit. These high-temperature methods will not apply to the
+majority of hardwoods, however, nor to many of the softwoods.
+
+It must first of all be recognized that the drying of lumber is a
+totally different operation from the drying of a fabric or of thin
+material. In the latter, it is largely a matter of evaporated
+moisture, but wood is not only hygroscopic and attracts moisture from
+the air, but its physical behavior is very complex and renders the
+extraction of moisture a very complicated process.
+
+An idea of its complexity may be had by mentioning some of the
+conditions which must be contended with. Shrinkage is, perhaps, the
+most important. This is unequal in different directions, being twice
+as great tangentially as radially and fifty times as great radially as
+longitudinally. Moreover, shrinkage is often unequal in different
+portions of the same piece. The slowness of the transfusion of
+moisture through the wood is an important factor. This varies with
+different woods and greatly in different directions. Wood becomes soft
+and plastic when hot and moist, and will yield more or less to
+internal stresses. As some species are practically impervious to air
+when wet, this plasticity of the cell walls causes them to collapse as
+the water passes outward from the cell cavities. This difficulty has
+given much trouble in the case of Western red cedar, and also to some
+extent in redwood. The unequal shrinkage causes internal stresses in
+the wood as it dries, which results in warping, checking,
+case-hardening, and honeycombing. Case-hardening is one of the most
+common defects in improperly dried lumber. It is clearly shown by the
+cupping of the two halves when a case-hardened board is resawed.
+Chemical changes also occur in the wood in drying, especially so at
+higher temperatures, rendering it less hygroscopic, but more brittle.
+If dried too much or at too high a temperature, the strength and
+toughness is seriously reduced.
+
+
+                         Conditions of Success
+
+Commercial success in drying therefore requires that the substance be
+exposed to the air in the most efficient manner; that the temperature
+of the air be as high as the substance will stand without injury, and
+that the air change or movement be as rapid as is consistent with
+economical installation and operation. Conditions of success therefore
+require the observance of the following points, which embody the basic
+principles of the process: (1) The timber should be heated through
+before drying begins. (2) The air should be very humid at the
+beginning of the drying process, and be made drier only gradually. (3)
+The temperature of the lumber must be maintained uniformly throughout
+the entire pile. (4) Control of the drying process at any given
+temperature must be secured by controlling the relative humidity, not
+by decreasing the circulation. (5) In general, high temperatures
+permit more rapid drying than do lower temperatures. The higher the
+temperature of the lumber, the more efficient is the kiln. It is
+believed that temperatures as high as the boiling point are not
+injurious to most woods, providing all other fundamentally important
+features are taken care of. Some species, however, are not able to
+stand as high temperatures as others, and (6) the degree of dryness
+attained, where strength is the prime requisite, should not exceed
+that at which the wood is to be used.
+
+
+                 Different Treatment according to Kind
+
+The rapidity with which water may be evaporated, that is, the rate of
+drying, depends on the size and shape of the piece and on the
+structure of the wood. Thin stock can be dried much faster than thick,
+under the same conditions of temperature, circulation, and humidity.
+Pine can be dried, as a general thing, in about one third of the time
+that would be required for oak of the same thickness, although the
+former contains the more water of the two. Quarter-sawn oak usually
+requires half again as long as plain oak. Mahogany requires about the
+same time as plain oak; ash dries in a little less time, and maple,
+according to the purpose for which it is intended, may be dried in one
+fifth the time needed for oak, or may require a slightly longer
+treatment. For birch, the time required is from one half to two
+thirds, and for poplar and basswood, from, one fifth to one third that
+required for oak.
+
+All kinds and thicknesses of lumber cannot be dried at the same time
+in the same kiln. It is manifest that green and air-dried lumber,
+dense and porous lumber, all require different treatment. For
+instance, Southern yellow pine when cut green from the log will stand
+a very high temperature, say 200 degrees Fahrenheit, and in fact this
+high temperature is necessary together with a rapid circulation of air
+in order to neutralize the acidity of the pitch which causes the wood
+to blue and discolor. This lumber requires to be heated up immediately
+and to be kept hot throughout the length of the kiln. Hence the kiln
+must not be of such length as to allow of the air being too much
+cooled before escaping.
+
+
+                          Temperature depends
+
+While it is true that a higher temperature can be carried in the kiln
+for drying pine and similar woods, this does not altogether account
+for the great difference in drying time, as experience has taught us
+that even when both woods are dried in the same kiln, under the same
+conditions, pine will still dry much faster, proving thereby that the
+structure of the wood itself affects drying.
+
+The aim of all kiln designers should be to dry in the shortest
+possible time, without injury to the material. Experience has
+demonstrated that high temperatures are very effective in evaporating
+water, regardless of the degree of humidity, but great care must be
+exercised in using extreme temperatures that the material to be dried
+is not damaged by checking, case-hardening, or hollow-horning.
+
+The temperature used should depend upon the species and condition of
+the material when entering the kiln. In general, it is advantageous to
+have as high a temperature as possible, both for economy of operation
+and speed of drying, but the physical properties of the wood will
+govern this.
+
+Many species cannot be dried satisfactorily at high temperatures on
+account of their peculiar behavior. This is particularly so with green
+lumber.
+
+Air-dried wood will stand a relatively higher temperature, as a rule,
+than wet or green wood. In drying green wood direct from the saw, it
+is usually best to start with a comparatively low temperature, and not
+raise the temperature until the wood is nearly dry. For example, green
+maple containing about 60 per cent of its dry weight in water should
+be started at about 120 degrees Fahrenheit and when it reaches a
+dryness of 25 per cent, the temperature may be raised gradually up to
+190 degrees.
+
+It is exceedingly important that the material be practically at the
+same temperature throughout if perfect drying is to be secured. It
+should be the same temperature in the center of a pile or car as on
+the outside, and the same in the center of each individual piece of
+wood as on its surface. This is the effect obtained by natural
+air-drying. The outside atmosphere and breezes (natural air
+circulation) are so ample that the heat extracted for drying does not
+appreciably change the temperature.
+
+When once the wood has been raised to a high temperature through and
+through and especially when the surface has been rendered most
+permeable to moisture, drying may proceed as rapidly as it can be
+forced by artificial circulation, provided the heat lost from the wood
+through vaporization is constantly replaced by the heat of the kiln.
+
+It is evident that to secure an even temperature, a free circulation
+of air must be brought in contact with the wood. It is also evident
+that in addition to heat and a circulation of air, the air must be
+charged with a certain amount of moisture to prevent surface drying or
+case-hardening.
+
+There are some twenty-five different makes of dry kilns on the market,
+which fulfill to a varying degree the fundamental requirements.
+Probably none of them succeed perfectly in fulfilling all.
+
+It is well to have the temperature of a dry kiln controlled by a
+thermostat which actuates the valve on the main steam supply pipe. It
+is doubly important to maintain a uniform temperature and avoid
+fluctuations in the dry kiln, since a change in temperature will
+greatly alter the relative humidity.
+
+In artificial drying, temperatures of from 150 to 180 degrees
+Fahrenheit are usually employed. Pine, spruce, cypress, cedar, etc.,
+are dried fresh from the saw, allowing four days for 1-inch stuff.
+Hardwoods, especially oak, ash, maple, birch, sycamore, etc., are
+usually air-seasoned for three to six months to allow the first
+shrinkage to take place more gradually, and are then exposed to the
+above temperatures in the kiln for about six to ten days for 1-inch
+stuff, other dimensions in proportion.
+
+Freshly cut poplar and cottonwood are often dried direct from the saw
+in a kiln. By employing lower temperatures, 100 to 120 degrees
+Fahrenheit, green oak, ash, etc., can be seasoned in dry kilns without
+much injury to the material.
+
+Steaming and sweating the wood is sometimes resorted to in order to
+prevent checking and case-hardening, but not, as has been frequently
+asserted, to enable the material to dry.
+
+
+                            Air Circulation
+
+Air circulation is of the utmost importance, since no drying whatever
+can take place when it is lacking. The evaporation of moisture
+requires heat and this must be supplied by the circulating air.
+Moreover, the moisture laden air must be constantly removed and fresh,
+drier air substituted. Probably this is the factor which gives more
+trouble in commercial operations than anything else, and the one which
+causes the greatest number of failures.
+
+It is necessary that the air circulate through every part of the kiln
+and that the moving air come in contact with every portion of the
+material to be dried. In fact, the humidity is dependent upon the
+circulation. If the air stagnates in any portion of the pile, then the
+temperature will drop and the humidity rise to a condition of
+saturation. Drying will not take place at this portion of the pile and
+the material is apt to mould and rot.
+
+The method of piling the material on trucks or in the kiln, is
+therefore, of extreme importance. Various methods are in use. Ordinary
+flat piling is probably the poorest. Flat piling with open chimney
+spaces in the piles is better. But neither method is suitable for a
+kiln in which the circulation is mainly vertical.
+
+Edge piling with stickers running vertically is in use in kilns when
+the heating coils are beneath. This is much better.
+
+Air being cooled as it comes in contact with a pile of material,
+becomes denser, and consequently tends to sink. Unless the material to
+be dried is so arranged that the air can pass gradually downward
+through the pile as it cools, poor circulation is apt to result.
+
+In edge-piled lumber, with the heating system beneath the piles, the
+natural tendency of the cooled air to descend is opposed by the hot
+air beneath which tends to rise. An indeterminate condition is thus
+brought about, resulting in non-uniform drying. It has been found that
+air will rise through some layers and descend through others.
+
+
+                               Humidity
+
+Humidity is of prime importance because the rate of drying and
+prevention of checking and case-hardening are largely dependent
+thereon. It is generally true that the surface of the wood should not
+dry more rapidly than the moisture transfuses from the center of the
+piece to its surface, otherwise disaster will result. As a sufficient
+amount of moisture is removed from the wood to maintain the desired
+humidity, it is not good economy to generate moisture in an outside
+apparatus and force it into a kiln, unless the moisture in the wood is
+not sufficient for this purpose; in that case provision should be made
+for adding any additional moisture that may be required.
+
+The rate of evaporation may best be controlled by controlling the
+amount of vapor present in the air (relative humidity); it should not
+be controlled by reducing the air circulation, since a large
+circulation is needed at all times to supply the necessary heat.
+
+The humidity should be graded from 100 per cent at the receiving end
+of the kiln, to whatever humidity corresponds with the desired degree
+of dryness at the delivery end.
+
+The kiln should be so designed that the proper degree may be
+maintained at its every section.
+
+A fresh piece of sapwood will lose weight in boiling water and can
+also be dried to quite an extent in steam. This proves conclusively
+that a high degree of humidity does not have the detrimental effect on
+drying that is commonly attributed to it. In fact, a proper degree of
+humidity, especially in the loading or receiving end of a kiln, is
+just as necessary to good results in drying as getting the proper
+temperature.
+
+Experiments have demonstrated also that injury to stock in the way of
+checking, warping, and hollow-horning always develops immediately
+after the stock is taken into the kiln, and is due to the degree of
+humidity being too low. The receiving end of the kiln should always be
+kept moist, where the stock has not been steamed before being put into
+the kiln. The reason for this is simple enough. When the air is too
+dry it tends to dry the outside of the material first--which is termed
+"case-hardening"--and in so doing shrinks and closes up the pores of
+the wood. As the stock is moved down the kiln, it absorbs a
+continually increasing amount of heat, which tends to drive off the
+moisture still present in the center of the stock. The pores on the
+outside having been closed up, there is no exit for the vapor or steam
+that is being rapidly formed in the center. It must find its way out
+some way, and in doing so sets up strains, which result either in
+checking, warping, or hollow-horning. If the humidity had been kept
+higher, the outside of the material would not have dried so quickly,
+and the pores would have remained open for the exit of moisture from
+the interior of the wood, and this trouble would have been avoided.
+
+Where the humidity is kept at a high point in the receiving end of the
+kiln, a higher rate of temperature may also be carried, and in that
+way the drying process is hastened with comparative safety.
+
+It is essential, therefore, to have an ample supply of heat through
+the convection currents of the air; but in the case of wood the rate
+of evaporation must be controlled, else checking will occur. This can
+be done by means of the relative humidity, as stated before. It is
+clear now that when the air--or, more properly speaking, the space--is
+completely saturated no evaporation can take place at the given
+temperature. By reducing the humidity, evaporation takes place more
+and more rapidly.
+
+Another bad feature of an insufficient and non-uniform supply of heat
+is that each piece of wood will be heated to the evaporating point on
+the outer surface, the inside remaining cool until considerable drying
+has taken place from the surface. Ordinarily in dry kilns high
+humidity and large circulation of air are antitheses to one another.
+To obtain the high humidity the circulation is either stopped
+altogether or greatly reduced, and to reduce the humidity a greater
+circulation is induced by opening the ventilators or otherwise
+increasing the draft. This is evidently not good practice, but as a
+rule is unavoidable in most dry kilns of present make. The humidity
+should be raised to check evaporation without reducing the circulation
+if possible.
+
+While thin stock, such as cooperage and box stuff is less inclined to
+give trouble by undue checking than 1-inch and thicker, one will find
+that any dry kiln will give more uniform results and, at the same
+time, be more economical in the use of steam, when the humidity and
+temperature is carried at as high a point as possible without injury
+to the material to be dried.
+
+Any well-made dry kiln which will fulfill the conditions required as
+to circulation and humidity control should work satisfactorily; but
+each case must be studied by itself, and the various factors modified
+to suit the peculiar conditions of the problem in hand. In every new
+case the material should be constantly watched and studied and, if
+checking begins, the humidity should be increased until it stops. It
+is not reducing the circulation, but adding the necessary moisture to
+the air, that should be depended on to prevent checking. For this
+purpose it is well to have steam jets in the kiln so that if needed
+they are ready at hand.
+
+
+                              Kiln-drying
+
+There are two distinct ways of handling material in dry kilns. One way
+is to place the load of lumber in a chamber where it remains in the
+same place throughout the operation, while the conditions of the
+drying medium are varied as the drying progresses. This is the
+"apartment" kiln or stationary method. The other is to run the lumber
+in at one end of the chamber on a wheeled truck and gradually move it
+along until the drying process is completed, when it is taken out at
+the opposite end of the kiln. It is the usual custom in these kilns to
+maintain one end of the chamber moist and the other end dry. This is
+known as the "progressive" type of kiln, and is the one most commonly
+used in large operations.
+
+It is, however, the least satisfactory of the two where careful drying
+is required, since the conditions cannot be so well regulated and the
+temperatures and humidities are apt to change with any change of wind.
+The apartment method can be arranged so that it will not require any
+more kiln space or any more handling of lumber than the progressive
+type. It does, however, require more intelligent operation, since the
+conditions in the drying chamber must be changed as the drying
+progresses. With the progressive type the conditions, once properly
+established, remain the same.
+
+To obtain draft or circulation three methods are in use--by forced
+draft or a blower usually placed outside the kiln, by ventilation, and
+by internal circulation and condensation. A great many patents have
+been taken out on different methods of ventilation, but in actual
+operation few kilns work exactly as intended. Frequently the air moves
+in the reverse direction for which the ventilators were planned.
+Sometimes a condenser is used in connection with the blower and the
+air is recirculated. It is also--and more satisfactorily--used with
+the gentle internal-gravity currents of air.
+
+Many patents have been taken out for heating systems. The differences
+among these, however, have more to do the mechanical construction than
+with the process of drying. In general, the heating is either direct
+or indirect. In the former steam coils are placed in the chamber with
+the lumber, and in the latter the air is heated by either steam coils
+or a furnace before it is introduced into the drying chamber.
+
+Moisture is sometimes supplied by means of free steam jets in the kiln
+or in the entering air; but more often the moisture evaporated from
+the lumber is relied upon to maintain the humidity necessary.
+
+A substance becomes dry by the evaporation of its inherent moisture
+into the surrounding space. If this space be confined it soon becomes
+saturated and the process stops. Hence, constant change is necessary
+in order that the moisture given off may be continually carried away.
+
+In practice, air movement, is therefore absolutely essential to the
+process of drying. Heat is merely a useful accessory which serves to
+decrease the time of drying by increasing both the rate of evaporation
+and the absorbing power of the surrounding space.
+
+It makes no difference whether this space is a vacuum or filled with
+air; under either condition it will take up a stated weight of vapor.
+From this it appears that the vapor molecules find sufficient space
+between the molecules of air. But the converse is not true, for
+somewhat less air will be contained in a given space saturated with
+vapor than in one devoid of moisture. In other words the air does not
+seem to find sufficient space between the molecules of vapor.
+
+If the temperature of the confined space be increased, opportunity
+will thereby be provided for the vaporization of more water, but if it
+be decreased, its capacity for moisture will be reduced and visible
+water will be deposited. The temperature at which this takes place is
+known as the "dew-point" and depends upon the initial degree of
+saturation of the given space; the less the relative saturation the
+lower the dew-point.
+
+Careful piling of the material to be dried, both in the yard and dry
+kiln, is essential to good results in drying.
+
+Air-dried material is not dry, and its moisture is too unevenly
+distributed to insure good behavior after manufacture.
+
+It is quite a difficult matter to give specific or absolute correct
+weights of any species of timber when thoroughly or properly dried, in
+order that one may be guided in these kiln operations, as a great deal
+depends upon the species of wood to be dried, its density, and upon
+the thickness which it has been cut, and its condition when entering
+the drying chamber.
+
+Elm will naturally weigh less than beech, and where the wood is
+close-grained or compact it will weigh more than coarse-grained wood
+of the same species, and, therefore, no set rules can be laid down, as
+good judgment only should be used, as the quality of the drying is not
+purely one of time. Sometimes the comparatively slow process gives
+excellent results, while to rush a lot of stock through the kiln may
+be to turn it out so poorly seasoned that it will not give
+satisfaction when worked into the finished product. The mistreatment
+of the material in this respect results in numerous defects, chief
+among which are warping and twisting, checking, case-hardening, and
+honeycombing, or, as sometimes called, hollow-horning.
+
+Since the proportion of sap and heartwood varies with size, age,
+species, and individual trees, the following figures as regards weight
+must be regarded as mere approximations:
+
+
+  POUNDS OF WATER LOST IN DRYING 100 POUNDS OF GREEN WOOD IN THE KILN
+
+=========================================================================
+                                                |Sapwood or | Heartwood
+                                                |outer part | or interior
+=========================================================================
+                                                |           |
+(1) Pine, cedar, spruce, and fir                |  45-65    |   16-25
+(2) Cypress, extremely variable                 |  50-65    |   18-60
+(3) Poplar, cottonwood, and basswood            |  60-65    |   40-60
+(4) Oak, beech, ash, maple, birch, elm, hickory,|           |
+    chestnut, walnut, and sycamore              |  40-50    |   30-40
+=========================================================================
+
+The lighter kinds have the most water in the sapwood; thus sycamore
+has more water than hickory, etc.
+
+The efficiency of the drying operations depends a great deal upon the
+way in which, the lumber is piled, especially when the humidity is not
+regulated. From the theory of drying it is evident that the rate of
+evaporation in dry kilns where the humidity is not regulated depends
+entirely upon the rate of circulation, other things being equal.
+Consequently, those portions of the wood which receive the greatest
+amount of air dry the most rapidly, and vice versa. The only way,
+therefore, in which anything like uniform drying can take place is
+where the lumber is so piled that each portion of it comes in contact
+with the same amount of air.
+
+In the Forestry Service kiln (Fig. 30), where the degree of relative
+humidity is used to control the rate of drying, the amount of
+circulation makes little difference, provided it exceeds a certain
+amount. It is desirable to pile the lumber so as to offer as little
+frictional resistance as possible and at the same time secure uniform
+circulation. If circulation is excessive in any place it simply means
+waste of energy but no other injury to the lumber.
+
+The best method of piling is one which permits the heated air to pass
+through the pile in a somewhat downward direction. The natural
+tendency of the cooled air to descend is thus taken advantage of in
+assisting the circulation in the kiln. This is especially important
+when cold or green lumber is first introduced into the kiln. But even
+when the lumber has become warmed the cooling due to the evaporation
+increases the density of the mixture of the air and vapor.
+
+
+                            Kiln-drying Gum
+
+The following article was published by the United States Forestry
+Service as to the best method of kiln-drying gum:
+
+=Piling.=--Perhaps the most important factor in good kiln-drying,
+especially in the case of the gums, is the method of piling. It is our
+opinion that proper and very careful piling will greatly reduce the
+loss due to warping. A good method of piling is to place the lumber
+lengthwise of the kiln and on an incline cross-wise. The warm air
+should rise at the higher side of the pile and descend between the
+courses of lumber. The reason for this is very simple and the
+principle has been applied in the manufacture of the best ice boxes
+for some time. The most efficient refrigerators are iced at the side,
+the ice compartment opening to the cooling chamber at the top and
+bottom. The warm air from above is cooled by melting the ice. It then
+becomes denser and settles down into the main chamber. The articles in
+the cooling room warm the air as they cool, so it rises to the top and
+again comes in contact with the ice, thus completing the cycle. The
+rate of this natural circulation is automatically regulated by the
+temperature of the articles in the cooling chamber and by the amount
+of ice in the icing compartment; hence the efficiency of such a box is
+high.
+
+Now let us apply this principle to the drying of lumber. First we must
+understand that as long as the lumber is moist and drying, it will
+always be cooler than the surrounding air, the amount of this
+difference being determined by the rate of drying and the moisture in
+the wood. As the lumber dries, its temperature gradually rises until
+it is equal to that of the air, when perfect dryness results. With
+this fact in mind it is clear that the function of the lumber in a
+kiln is exactly analogous to that of the ice in an ice box; that is,
+it is the cooling agent. Similarly, the heating pipes in a dry kiln
+bring about the same effect as the articles of food in the ice box in
+that they serve to heat the air. Therefore, the air will be cooled by
+the lumber, causing it to pass downward through the piles. If the
+heating units are placed at the sides of the kiln, the action of the
+air in a good ice box is duplicated in the kiln. The significant point
+in this connection is that, the greener and colder the lumber, the
+faster is the circulation. This is a highly desirable feature.
+
+A second vital point is that as the wood becomes gradually drier the
+circulation automatically decreases, thus resulting in increased
+efficiency, because there is no need for circulation greater than
+enough to maintain the humidity of the air as it leaves the lumber
+about the same as it enters. Therefore, we advocate either the
+longitudinal side-wise inclined pile or edge stacking, the latter
+being much preferable when possible. Of course the piles in our kiln
+were small and could not be weighted properly, so the best results as
+to reducing warping were not obtained.
+
+=Preliminary Steaming.=--Because the fibres of the gums become plastic
+while moist and hot without causing defects, it is desirable to heat
+the air-dried lumber to about 200 degrees Fahrenheit in saturated
+steam at atmospheric pressure in order to reduce the warping. This
+treatment also furnishes a means of heating the lumber very rapidly.
+It is probably a good way to stop the sap-staining of green lumber, if
+it is steamed while green. We have not investigated the other effects
+of steaming green gum, however, so we hesitate to recommend it.
+
+Temperatures as high as 210 degrees Fahrenheit were used with no
+apparent harm to the material. The best result was obtained with the
+temperature of 180 degrees Fahrenheit, after the first preliminary
+heating in steam to 200 degrees Fahrenheit. Higher temperatures may be
+used with air-dried gum, however.
+
+The best method of humidity control proved to be to reduce the
+relative humidity of the air from 100 per cent (saturated steam) very
+carefully at first and then more rapidly to 30 per cent in about four
+days. If the change is too marked immediately after the steaming
+period, checking will invariably result. Under these temperature and
+humidity conditions the stock was dried from 15 per cent moisture,
+based on the dry wood weight, to 6 per cent in five days' time. The
+loss due to checking was about 5 per cent, based on the actual footage
+loss, not on commercial grades.
+
+=Final Steaming.=--From time to time during the test runs the material
+was resawed to test for case-hardening. The stock dried in five days
+showed slight case-hardening, so it was steamed at atmospheric
+pressure for 36 minutes near the close of the run, with the result
+that when dried off again the stresses were no longer present. The
+material from one run was steamed for three hours at atmospheric
+pressure and proved very badly case-hardened, but in the reverse
+direction. It seems possible that by testing for the amount of
+case-hardening one might select a final steaming period which would
+eliminate all stresses in the wood.
+
+
+                     Kiln-drying of Green Red Gum
+
+The following article was published by the United States Forestry
+Service on the kiln-drying of green red gum:
+
+A short time ago fifteen fine, red-gum logs 16 feet long were received
+from Sardis, Miss. They were in excellent condition and quite green.
+
+It has been our belief that if the gum could be kiln-dried directly
+from the saw, a number of the difficulties in seasoning might be
+avoided. Therefore, we have undertaken to find out whether or not such
+a thing is feasible. The green logs now at the laboratory are to be
+used in this investigation. One run of a preliminary nature has just
+been made, the method and results of which I will now tell.
+
+This method was really adapted to the drying of Southern pine, and one
+log of the green gum was cut into 1-inch stock and dried with the
+pine. The heartwood contained many knots and some checks, although it
+was in general of quite good quality. The sapwood was in fine
+condition and almost as white as snow.
+
+This material was edge-stacked with one crosser at either end and one
+at the center, of the 16-foot board. This is sufficient for the pine,
+but was absolutely inadequate for drying green gum. A special
+shrinkage take-up was applied at the three points. The results proved
+very interesting in spite of the warping which was expected with but
+three crossers in 16 feet. The method of circulation described was
+used. It is our belief that edge piling is best for this method.
+
+This method of kiln-drying depends on the maintenance of a high
+velocity of slightly superheated steam through the lumber. In few
+words, the object is to maintain the temperature of the vapor as it
+leaves the lumber at slightly above 212 degrees Fahrenheit. In order
+to accomplish this result, it is necessary to maintain the high
+velocity of circulation. As the wood dries, the superheat may be
+increased until a temperature of 225 degrees or 230 degrees Fahrenheit
+of the exit air is recorded.
+
+The 1-inch green gum was dried from 20.1 per cent to 11.4 per cent
+moisture, based on the dry wood weight in 45 hours. The loss due to
+checking was 10 per cent. Nearly every knot in the heartwood was
+checked, showing that as the knots could be eliminated in any case,
+this loss might not be so great. It was significant that practically
+all of the checking occurred in the heartwood. The loss due to warping
+was 22 per cent. Of course this was large; but not nearly enough
+crossers were used for the gum. It is our opinion that this loss due
+to warping can be very much reduced by using at least eight crossers
+and providing for taking up of the shrinkage. A feature of this
+process which is very important is that the method absolutely prevents
+all sap staining.
+
+Another delightful surprise was the manner in which the superheated
+steam method of drying changed the color of the sapwood from pure
+white to a beautifully uniform, clean-looking, cherry red color which
+very closely resembles that of the heartwood. This method is not new
+by any means, as several patents have been granted on the steaming of
+gum to render the sapwood more nearly the color of the heartwoods. The
+method of application in kiln-drying green gum we believe to be new,
+however. Other methods for kiln-drying this green stock are to be
+tested until the proper process is developed. We expect to have
+something interesting to report in the near future.[1]
+
+    [Footnote 1: The above test was made at the United States
+    Forestry Service Laboratory, Madison, Wis.]
+
+
+
+
+                              SECTION XII
+
+                          TYPES OF DRY KILNS
+
+                     DIFFERENT TYPES OF DRY KILNS
+
+
+Dry kilns as in use to-day are divided into two classes: The "pipe" or
+"moist-air" kiln, in which natural draft is relied upon for
+circulation and, the "blower" or "hot blast" kiln, in which the
+circulation is produced by fans or blowers. Both classes have their
+adherents and either one will produce satisfactory results if properly
+operated.
+
+
+                   The "Blower" or "Hot Blast" Kiln
+
+The blower kiln in its various types has been in use so long that it
+is hardly necessary to give to it a lengthy introduction. These kilns
+at their inauguration were a wonderful improvement over the old style
+"bake-oven" or "sweat box" kiln then employed, both on account of the
+improved quality of the material and the rapidity at which it was
+dried.
+
+These blower kilns have undergone steady improvement, not only in the
+apparatus and equipment, but also in their general design, method of
+introducing air, and provision for controlling the temperature and
+humidity. With this type of kiln the circulation is always under
+absolute control and can be adjusted to suit the conditions, which
+necessarily vary with the conditions of the material to be dried and
+the quantity to be put through the kiln.
+
+In either the blower or moist-air type of dry kiln, however, it is
+absolutely essential, in order to secure satisfactory results, both as
+to rapidity in drying and good quality of stock, that the kiln be so
+designed that the temperature and humidity, together with circulation,
+are always under convenient control. Any dry kiln in which this has
+not been carefully considered will not give the desired results.
+
+In the old style blower kiln, while the circulation and temperature
+was very largely under the operator's control, it was next to
+impossible to produce conditions in the receiving end of the kiln so
+that the humidity could be kept at the proper point. In fact, this was
+one reason why the natural draft, or so-called moist-air kiln was
+developed.
+
+The advent of the moist-air kiln served as an education to kiln
+designers and manufacturers, in that it has shown conclusively the
+value of a proper degree of humidity in the receiving end of any
+progressive dry kiln, and it has been of special benefit also in that
+it gave the manufacturers of blower kilns an idea as to how to improve
+the design of their type of kiln to overcome the difficulty referred
+to in the old style blower kilns. This has now been remedied, and in a
+decidedly simple manner, as is usually the case with all things that
+possess merit.
+
+It was found that by returning from one third to one half of the moist
+air _after_ having passed through the kiln back to the fan room and by
+mixing it with the fresh and more or less dry air going into the
+drying room, that the humidity could be kept under convenient control.
+
+The amount of air that can be returned from a kiln of this class
+depends upon three things: (1) The condition of the material when
+entering the drying room; (2) the rapidity with which the material is
+to be dried; and (3) the condition of the outside atmosphere. In the
+winter season it will be found that a larger proportion of air may be
+returned to the drying room than in summer, as the air during the
+winter season contains considerably less moisture and as a consequence
+is much drier. This is rather a fortunate coincidence, as, when the
+kiln is being operated in this manner, it will be much more economical
+in its steam consumption.
+
+In the summer season, when the outside atmosphere is saturated to a
+much greater extent, it will be found that it is not possible to
+return as great a quantity of air to the drying room, although there
+have been instances of kilns of this class, which in operation have
+had all the air returned and found to give satisfactory results. This
+is an unusual condition, however, and can only be accounted for by
+some special or peculiar condition surrounding the installation.
+
+In some instances, the desired amount of humidity in a blower type of
+kiln is obtained by the addition of a steam spray in the receiving end
+of the kiln, much in the same manner as that used in the moist-air
+kilns. This method is not as economical as returning the
+moisture-laden air from the drying room as explained in the preceding
+paragraph.
+
+With the positive circulation that may be obtained in a blower kiln,
+and with the conditions of temperature and humidity under convenient
+control, this type of kiln has the elements most necessary to produce
+satisfactory drying in the quickest possible elapsed time.
+
+It must not be inferred from this, however, that this class of dry
+kiln may be installed and satisfactory results obtained regardless of
+how it is handled. A great deal of the success of any dry kiln--or any
+other apparatus, for that matter--depends upon intelligent operation.
+
+
+                  Operation of the "Blower" Dry Kiln
+
+It is essential that the operator be supplied with proper facilities
+to keep a record of the material as it is placed into the drying room,
+and when it is taken out. An accurate record should be kept of the
+temperature every two or three hours, for the different thicknesses
+and species of lumber, that he may have some reliable data to guide
+him in future cases.
+
+Any man possessing ordinary intelligence can operate dry kilns and
+secure satisfactory results, providing he will use good judgment and
+follow the basic instructions as outlined below:
+
+     1. When cold and before putting into operation, heat the
+     apparatus slowly until all pipes are hot, then start the fan
+     or blower, gradually bringing it up to its required speed.
+
+     2. See that _all_ steam supply valves are kept wide open,
+     unless you desire to lengthen the time required to dry the
+     material.
+
+     3. When using exhaust steam, the valve from the header
+     (which is a separate drip, independent of the trap
+     connection) must be kept wide open, but must be closed when
+     live steam is used on that part of the heater.
+
+     4. The engines as supplied by the manufacturers are
+     constructed to operate the fan or blower at a proper speed
+     with its throttle valve wide open, and with not less than 80
+     pounds pressure of steam.
+
+     5. If the return steam trap does not discharge regularly, it
+     is important that it be opened and thoroughly cleaned and
+     the valve seat re-ground.
+
+     6. As good air circulation is as essential as the proper
+     degree of heat, and as the volume of air and its contact
+     with the material to be dried depends upon the volume
+     delivered by the fan or blower, it is necessary to maintain
+     a regular and uniform speed of the engine.
+
+     7. Atmospheric openings must always be maintained in the fan
+     or heater room for fresh air supply.
+
+     8. Successful drying cannot be accomplished without ample
+     and free circulation of air at all times.
+
+If the above instructions are fully carried out, and good judgment
+used in the handling and operation of the blower kiln, no difficulties
+should be encountered in successfully drying the materials at hand.
+
+
+                  The "Pipe" or "Moist-air" Dry Kiln
+
+While in the blower class of dry kiln, the circulation is obtained by
+forced draft with the aid of fans or blowers, in the Moist-air kilns
+(see Fig. 31); the circulation is obtained by natural draft only,
+aided by the manipulation of dampers installed at the receiving end of
+the drying room, which lead to vertical flues through a stack to the
+outside atmosphere.
+
+The heat in these kilns is obtained by condensing steam in coils of
+pipe, which are placed underneath the material to be dried. As the
+degree of heat required, and steam pressure govern the amount of
+radiation, there are several types of radiating coils. In Fig. 32 will
+be seen the Single Row Heating Coils for live or high pressure steam,
+which are used when the low temperature is required. Figure 33 shows
+the Double (or 2) Row Heating Coils for live or high pressure steam.
+This apparatus is used when a medium temperature is required. In Fig.
+34 will be seen the Vertical Type Heating Coils which is recommended
+where exhaust or low-pressure steam is to be used, or may be used with
+live or high-pressure steam when high temperatures are desired.
+
+    [Illustration: Fig. 31. Section through a typical Moist-air
+    Dry Kiln.]
+
+These heating coils are usually installed in sections, which permit
+any degree of heat from the minimum to the maximum to be maintained by
+the elimination of, or the addition of, any number of heating
+sections. This gives a dry kiln for the drying of green softwoods, or
+by shutting off a portion of the radiating coils--thus reducing the
+temperature--a dry kiln for drying hardwoods, that will not stand the
+maximum degree of heat.
+
+    [Illustration: Fig. 32. Single Pipe Heating Apparatus for Dry
+    Kilns, arranged for the Use of Live Steam. For Low
+    Temperatures.]
+
+    [Illustration: Fig. 33. Double Pipe Heating Apparatus for Dry
+    Kilns, arranged for the Use of Live Steam. For Medium
+    Temperatures.]
+
+In the Moist-air or Natural Draft type of dry kiln, any degree of
+humidity, from clear and dry to a dense fog may be obtained; this is
+in fact, the main and most important feature of this type of dry kiln,
+and the most essential one in the drying of hardwoods.
+
+It is not generally understood that the length of a kiln has any
+effect upon the quantity of material that may be put through it, but
+it is a fact nevertheless that long kilns are much more effective, and
+produce a better quality of stock in less time than kilns of shorter
+length.
+
+Experience has proven that a kiln from 80 to 125 feet in length will
+produce the best results, and it should be the practice, where
+possible, to keep them within these figures. The reason for this is
+that in a long kiln there is a greater drop in temperature between the
+discharge end and the green or receiving end of the kiln.
+
+It is very essential that the conditions in the receiving end of the
+kiln, as far as the temperature and humidity are concerned, must go
+hand in hand.
+
+It has also been found that in a long kiln the desired conditions may
+be obtained with higher temperatures than with a shorter kiln;
+consequently higher temperatures may be carried in the discharge end
+of the kiln, thereby securing greater rapidity in drying. It is not
+unusual to find that a temperature of 200 degrees Fahrenheit is
+carried in the discharge end of a long dry kiln with safety, without
+in any way injuring the quality of the material, although, it would be
+better not to exceed 180 degrees in the discharge end, and about 120
+degrees in the receiving or green end in order to be on the safe side.
+
+
+                 Operation of the "Moist-air" Dry Kiln
+
+To obtain the best results these kilns should be kept in continuous
+operation when once started, that is, they should be operated
+continuously day and night. When not in operation at night or on
+Sundays, and the kiln is used to season green stock direct from the
+saw, the large doors at both ends of the kiln should be opened wide,
+or the material to be dried will "sap stain."
+
+    [Illustration: Fig. 34. Vertical Pipe Heating Apparatus for
+    Dry Kilns; may be used in Connection with either Live or
+    Exhaust Steam for High or Low Temperatures.]
+
+It is highly important that the operator attending any drying
+apparatus keep a minute and accurate record of the condition of the
+material as it is placed into the drying room, and its final condition
+when taken out.
+
+Records of the temperature and humidity should be taken frequently and
+at stated periods for the different thicknesses and species of
+material, in order that he may have reliable data to guide him in
+future operations.
+
+The following facts should be taken into consideration when operating
+the Moist-air dry kiln:
+
+     1. Before any material has been placed in the drying room,
+     the steam should be turned into the heating or radiating
+     coils, gradually warming them, and bringing the temperature
+     in the kiln up to the desired degree.
+
+     2. Care should be exercised that there is sufficient
+     humidity in the receiving or loading end of the kiln, in
+     order to guard against checking, case-hardening, etc.
+     Therefore it is essential that the steam spray at the
+     receiving or loading end of the kiln be properly
+     manipulated.
+
+     3. As the temperature depends principally upon the pressure
+     of steam carried in the boilers, maintain a steam pressure
+     of not less than 80 pounds at all times; it may range as
+     high as 100 pounds. The higher the temperature with its
+     relatively high humidity the more rapidly the drying will be
+     accomplished.
+
+     4. Since air circulation is as essential as the proper
+     degree of heat, and as its contact with the material to be
+     dried depends upon its free circulation, it is necessary
+     that the dampers for its admittance into, and its exit from,
+     the drying room be efficiently and properly operated.
+     Successful drying cannot be accomplished without ample and
+     free circulation of air at all times during the drying
+     process.
+
+If the above basic principles are carefully noted and followed out,
+and good common sense used in the handling and operation of the kiln
+apparatus, no serious difficulties should arise against the successful
+drying of the materials at hand.
+
+
+                        Choice of Drying Method
+
+At this point naturally arises the question: Which of the two classes
+of dry kilns, the "Moist-air" or "Blower" kiln is the better adapted
+for my particular needs?
+
+This must be determined entirely by the species of wood to be dried,
+its condition when it goes into the kiln, and what kind of finished
+product is to be manufactured from it.
+
+Almost any species of hardwood which has been subjected to
+air-seasoning for three months or more may be dried rapidly and in the
+best possible condition for glue-jointing and fine finishing with a
+"Blower" kiln, but green hardwood, direct from the saw, can only be
+successfully dried (if at all) in a "Moist-air" kiln.
+
+Most furniture factories have considerable bent stock which must of
+necessity be thoroughly steamed before bending. By steaming, the
+initial process of the Moist-air kiln has been consummated. Hence, the
+Blower kiln is better adapted to the drying of such stock than the
+Moist-air kiln would be, as the stock has been thoroughly soaked by
+the preliminary steaming, and all that is required is sufficient heat
+to volatilize the moisture, and a strong circulation of air to remove
+it as it comes to the surface.
+
+The Moist-air kiln is better adapted to the drying of tight cooperage
+stock, while the Blower kiln is almost universally used throughout the
+slack cooperage industry for the drying of its products.
+
+For the drying of heavy timbers, planks, blocks, carriage stock, etc.,
+and for all species of hardwood thicker than one inch, the Moist-air
+kiln is undoubtedly the best.
+
+Both types of kilns are equally well adapted to the drying of 1-inch
+green Norway and white pine, elm, hemlock, and such woods as are used
+in the manufacture of flooring, ceiling, siding, shingles, hoops, tub
+and pail stock, etc.
+
+The selection of one or the other for such work is largely matter of
+personal opinion.
+
+
+                       Kilns of Different Types
+
+All dry kilns as in use to-day are divided as to method of drying into
+two classes:
+
+    The "Pipe" or "Moist-air" kiln;
+    The "Blower" or "Hot Blast" kiln;
+
+both of which have been fully explained in a previous article.
+
+The above two classes are again subdivided into five different types
+of dry kilns as follows:
+
+    The "Progressive" kiln;
+    The "Apartment" kiln;
+    The "Pocket" kiln;
+    The "Tower" kiln;
+    The "Box" kiln.
+
+
+                      The "Progressive" Dry Kiln
+
+Dry kilns constructed so that the material goes in at one end and is
+taken out at the opposite end are called Progressive dry kilns, from
+the fact that the material gradually progresses through the kiln from
+one stage to another while drying (see Fig. 31).
+
+In the operation of the Progressive kiln, the material is first
+subjected to a sweating or steaming process at the receiving or
+loading end of the kiln with a low temperature and a relative high
+humidity. It then gradually progresses through the kiln into higher
+temperatures and lower humidities, as well as changes of air
+circulation, until it reaches the final stage at the discharge end of
+the kiln.
+
+Progressive kilns, in order to produce the most satisfactory results,
+especially in the drying of hardwoods or heavy softwood timbers,
+should be not less than 100 feet in length (see Fig. 35).
+
+In placing this type of kiln in operation, the following instructions
+should be carefully followed:
+
+When steam has been turned into the heating coils, and the kiln is
+fairly warm, place the first car of material to be dried in the drying
+room--preferably in the morning--about 25 feet from the kiln door on
+the receiving or loading end of the kiln, blocking the wheels so that
+it will remain stationary.
+
+    [Illustration: Fig. 35. Exterior View of Four Progressive Dry
+    Kilns, each 140 Feet long by 18 Feet wide. Cross-wise piling,
+    fire-proof construction.]
+
+Five hours later, or about noon, run in the second car and stop it
+about five feet from the first one placed in the drying room. Five
+hours later, or in the evening push car number two up against the
+first car; then run in car number three, stopping it about five feet
+from car number two.
+
+On the morning of the second day, push car number three against the
+others, and then move them all forward about 25 feet, and then run in
+car number four, stopping it about five feet from the car in advance
+of it. Five hours later, or about noon, run in car number five and
+stop it about five feet from car number four. In the evening or about
+five hours later, push these cars against the ones ahead, and run in
+loaded car number six, stopping it about five feet from the preceding
+car.
+
+On the morning of the third day, move all the cars forward about six
+feet; then run in loaded car number seven stop it about four feet from
+the car preceding it. Five hours later or about noon push this car
+against those in advance of it, and run in loaded car number eight
+moving all cars forward about six feet, and continue in this manner
+until the full complement of cars have been placed in the kiln. When
+the kiln has been filled, remove car number one and push all the
+remaining cars forward and run in the next loaded car, and continue in
+this manner as long as the kiln is in operation.
+
+As the temperature depends principally upon the pressure of steam,
+maintain a steam pressure of not less than 80 pounds at all times; it
+may range up to as high as 100 pounds. The higher the temperature with
+a relatively higher humidity the more rapidly the drying will be
+accomplished.
+
+If the above instructions are carried out, the temperatures,
+humidities, and air circulation properly manipulated, there should be
+complete success in the handling of this type of dry kiln.
+
+The Progressive type of dry kiln is adapted to such lines of
+manufacture that have large quantities of material to kiln-dry where
+the species to be dried is of a similiar nature or texture, and does
+not vary to any great extent in its thickness, such, for instance, as:
+
+    Oak flooring plants;
+    Maple flooring plants;
+    Cooperage plants;
+    Large box plants;
+    Furniture factories; etc.
+
+In the selection of this kind of dry kiln, consideration should be
+given to the question of ground space of sufficient length or
+dimension to accommodate a kiln of proper length for successful
+drying.
+
+
+                       The "Apartment" Dry Kiln
+
+The Apartment system of dry kilns are primarily designed for the
+drying of different kinds or sizes of material at the same time, a
+separate room or apartment being devoted to each species or size when
+the quantity is sufficient (see Fig. 36).
+
+These kilns are sometimes built single or in batteries of two or more,
+generally not exceeding 40 or 50 feet in length with doors and
+platforms at both ends the same as the Progressive kilns; but in
+operation each kiln is entirely filled at one loading and then closed,
+and the entire contents dried at one time, then emptied and again
+recharged.
+
+Any number of apartments may be built, and each apartment may be
+arranged to handle any number of cars, generally about three or four,
+or they may be so constructed that the material is piled directly upon
+the floor of the drying room.
+
+    [Illustration: Fig. 36. Exterior View of Six Apartment Dry
+    Kilns, each 10 Feet wide by 52 Feet long, End-wise Piling.
+    They are entirely of fire-proof construction and equipped
+    with double doors (Hussey asbestos outside and canvas
+    inside), and are also equipped with humidity and air control
+    dampers, which may be operated from the outside without
+    opening the kiln doors, which is a very good feature.]
+
+When cars are used, it is well to have a transfer car at each end of
+the kilns, and stub tracks for holding cars of dry material, and for
+the loading of the unseasoned stock, as in this manner the kilns may
+be kept in full operation at all times.
+
+In this type of dry kiln the material receives the same treatment and
+process that it would in a Progressive kiln. The advantages of
+Apartment kilns is manifest where certain conditions require the
+drying of numerous kinds as well as thicknesses of material at one and
+the same time. This method permits of several short drying rooms or
+apartments so that it is not necessary to mix hardwoods and softwoods,
+or thick and thin material in the same kiln room.
+
+In these small kilns the circulation is under perfect control, so that
+the efficiency is equal to that of the more extensive plants, and will
+readily appeal to manufacturers whose output calls for the prompt and
+constant seasoning of a large variety of small stock, rather than a
+large volume of material of uniform size and grade.
+
+Apartment kilns are recommended for industries where conditions
+require numerous kinds and thicknesses of material to be dried, such
+as:
+
+    Furniture factories;
+    Piano factories;
+    Interior woodwork mills;
+    Planing mills; etc.
+
+
+                         The "Pocket" Dry Kiln
+
+"Pocket" dry kilns (see Fig. 37) are generally built in batteries of
+several pockets. They have the tracks level and the lumber goes in and
+out at the same end. Each drying room is entirely filled at one time,
+the material is dried and then removed and the kiln again recharged.
+
+The length of "Pocket" kilns ranges generally from 14 feet to about 32
+feet.
+
+The interior equipment for this type of dry kiln is arranged very
+similiar to that used in the Apartment kiln. The heating or radiating
+coils and steam spray jets extend the whole length of the drying room,
+and are arranged for the use of either live or exhaust steam, as
+desired.
+
+Inasmuch as Pocket kilns have doors at one end only, this feature
+eliminates a certain amount of door exposure, which conduces towards
+economy in operation.
+
+In operating Pocket kilns, woods of different texture and thickness
+should be separated and placed in different drying rooms, and each
+kiln adjusted and operated to accommodate the peculiarities of the
+species and thickness of the material to be dried.
+
+    [Illustration: Fig. 37. Exterior View of Five Pocket Dry
+    Kilns, built in Two Batteries with the Front of each Set
+    facing the other, and a Transfer System between. They are
+    also equipped with the asbestos doors.]
+
+Naturally, the more complex the conditions of manufacturing wood
+products in any industry, the more difficult will be the proper
+drying of same. Pocket kilns, are, therefore, recommended for
+factories having several different kinds and thicknesses of material
+to dry in small quantities of each, such as:
+
+    Planing mills;
+    Chair factories;
+    Furniture factories;
+    Sash and door factories; etc.
+
+
+                         The "Tower" Dry Kiln
+
+The so-called "Tower" dry kiln (see Fig. 38) is designed for the rapid
+drying of small stuff in quantities. Although the general form of
+construction and the capacity of the individual bins or drying rooms
+may vary, the same essential method of operation is common to all.
+That is, the material itself, such as wooden novelties, loose staves,
+and heading for tubs, kits, and pails, for box stuff, kindling wood,
+etc., is dumped directly into the drying rooms from above, or through
+the roof, in such quantities as effectually to fill the bin, from
+which it is finally removed when dry, through the doors at the bottom.
+
+These dry kilns are usually operated as "Blower" kilns, the heating
+apparatus is generally located in a separate room or building adjacent
+to the main structure or drying rooms, and arranged so that the hot
+air discharged through the inlet duct (see illustration) is thoroughly
+distributed beneath a lattice floor upon which rests the material to
+be dried. Through this floor the air passes directly upward, between
+and around the stock, and finally returns to the fan or heating room.
+
+This return air duct is so arranged that by means of dampers, leading
+from each drying room, the air may be returned in any quantity to the
+fan room where it is mixed with fresh air and again used. This is one
+of the main features of economy of the blower system of drying, as by
+the employment of this return air system, considerable saving may be
+made in the amount of steam required for drying.
+
+    [Illustration: Fig. 38. Exterior and Sectional View of a
+    Battery of Tower Dry Kilns. This is a "Blower" or "Hot Blast"
+    type, and shows the arrangement of the fan blower, engine,
+    etc. This type of dry kin is used principally for the
+    seasoning of small, loose material.]
+
+The lattice floors in this type of dry kiln are built on an incline,
+which arrangement materially lessens the cost, and increases the
+convenience with which the dried stock may be removed from the bins or
+drying rooms.
+
+In operation, the material is conveyed in cars or trucks on an
+overhead trestle--which is inclosed--from which the material to be
+dried is dumped directly into the drying rooms or bins, through
+hoppers arranged for that purpose thereby creating considerable saving
+in the handling of the material to be dried into the kiln. The entire
+arrangement thus secures the maximum capacity, with a minimum amount
+of floor space, with the least expense. Of course, the higher these
+kilns are built, the less relative cost for a given result in the
+amount of material dried.
+
+In some instances, these kilns are built less in height and up against
+an embankment so that teamloads of material may be run directly onto
+the roof of the kilns, and dumped through the hoppers into the drying
+rooms or bins, thus again reducing to a minimum the cost of this
+handling.
+
+The return air duct plays an important part in both of these methods
+of filling, permitting the air to become saturated to the maximum
+desired, and utilizing much of the heat contained therein, which would
+otherwise escape to the atmosphere.
+
+The "Tower" kiln is especially adapted to factories of the following
+class:
+
+    Sawmills;
+    Novelty factories;
+    Woodenware factories;
+    Tub and pail factories; etc.
+
+
+                          The "Box" Dry Kiln
+
+The "Box" kiln shown in Figure 39 is an exterior view of a kiln of
+this type which is 20 feet wide, 19 feet deep, and 14 feet high, which
+is the size generally used when the space will permit.
+
+Box kilns are used mostly where only a small quantity of material is
+to be dried. They are not equipped with trucks or cars, the material
+to be dried being piled upon a raised platform inside the drying
+room. This arrangement, therefore, makes them of less cost than the
+other types of dry kilns.
+
+They are particularly adapted to any and all species and size of
+lumber to be dried in very small quantities.
+
+    [Illustration: Fig. 39. Exterior view of the Box Dry Kiln.
+    This particular kiln is 20 feet wide, 19 feet deep and 14
+    feet high. Box kilns are used mostly where only a small
+    amount of kiln-dried lumber of various sizes is required.
+    They are not equipped with trucks or cars, and therefore cost
+    less to construct than any other type of dry kiln.]
+
+In these small kilns the circulation is under perfect control, so that
+the efficiency is equal to that of the more extensive plants.
+
+These special kilns will readily appeal to manufacturers, whose output
+calls for the prompt and constant seasoning of a large variety of
+small stock, rather than a large volume material of uniform size and
+grade.
+
+
+
+
+                             SECTION XIII
+
+                         DRY KILN SPECIALTIES
+
+                    KILN CARS AND METHOD OF LOADING
+
+
+Within recent years, the edge-wise piling of lumber (see Figs. 40 and
+41), upon kiln cars has met with considerable favor on account of its
+many advantages over the older method of flat piling. It has been
+proven that lumber stacked edge-wise dries more uniformly and rapidly,
+and with practically no warping or twisting of the material, and that
+it is finally discharged from the dry kiln in a much better and
+brighter condition. This method of piling also considerably increases
+the holding and consequent drying capacities of the dry kiln by reason
+of the increased carrying capacities of the kiln cars, and the shorter
+period of time required for drying the material.
+
+    [Illustration: Fig. 40. Car Loaded with Lumber on its Edges
+    by the Automatic Stacker, to go into the Dry Kiln cross-wise.
+    Equipped with two edge piling kiln trucks.]
+
+In Figures 42 and 43 are shown different views of the automatic lumber
+stacker for edge-wise piling of lumber on kiln cars. Many users of
+automatic stackers report that the grade of their lumber is raised to
+such an extent that the system would be profitable for this reason
+alone, not taking into consideration the added saving in time and
+labor, which to anyone's mind should be the most important item.
+
+    [Illustration: Fig. 41. Car Loaded with Lumber on its Edges
+    by the Automatic Stacker, to go into the Dry Kiln end-wise.
+    The bunks on which the lumber rests are channel steel. The
+    end sockets are malleable iron and made for I-beam stakes.]
+
+In operation, the lumber is carried to these automatic stackers on
+transfer chains or chain conveyors, and passes on to the stacker
+table. When the table is covered with boards, the "lumber" lever is
+pulled by the operator, which raises a stop, preventing any more
+lumber leaving the chain conveyor. The "table" lever then operates the
+friction drive and raises the table filled with the boards to a
+vertical position. As the table goes up, it raises the latches, which
+fall into place behind the piling strips that had been previously laid
+on the table. When the table returns to the lower position, a new set
+of piling strips are put in place on the table, and the stream of
+boards which has been accumulating on the conveyor chain are again
+permitted to flow onto the table. As each layer of lumber is added,
+the kiln car is forced out against a strong tension. When the car is
+loaded, binders are put on over the stakes by means of a powerful
+lever arrangement.
+
+    [Illustration: Fig. 42. The above illustration shows the
+    construction of the Automatic Lumber Stacker for edge piling
+    of lumber to go into the dry kiln end-wise.]
+
+    [Illustration: Fig. 43. The above illustration shows the
+    construction of the Automatic Lumber Stacker for edge piling
+    of lumber to go into the dry kiln cross-wise.]
+
+    [Illustration: Fig. 44. The above illustration shows a
+    battery of Three Automatic Lumber Stackers.]
+
+    [Illustration: Fig. 45. The above illustration shows another
+    battery of Three Automatic Lumber Stackers.]
+
+    [Illustration: Fig. 46. Cars Loaded with Lumber on its Edges
+    by the Automatic Lumber Stackers.]
+
+After leaving the dry kilns, the loaded car is transferred to the
+unstacker (see Fig. 47). Here it is placed on the unstacker car which,
+by means of a tension device, holds the load of lumber tight against
+the vertical frame of the unstacker. The frame of the unstacker is
+triangular and has a series of chains. Each chain has two special
+links with projecting lugs. The chains all travel in unison. The lug
+links engage a layer of boards, sliding the entire layer vertically,
+and the boards, one at a time, fall over the top of the unstacker
+frame onto the inclined table, and from there onto conveyor chains
+from which they may be delivered to any point desired, depending upon
+the length and direction of the chain conveyor.
+
+With these unstackers one man can easily unload a kiln car in twenty
+minutes or less.
+
+    [Illustration: Fig. 47. The Lumber Unstacker Car, used for
+    unloading cars of Lumber loaded by the Automatic Stacker.]
+
+    [Illustration: Fig. 48. The Lumber Unstacker Car and
+    Unstacker, used for unloading Lumber loaded by the Automatic
+    Stacker.]
+
+The experience of many users prove that these edge stacking machines
+are not alike. This is important, because there is one feature of edge
+stacking that must not be overlooked. Unless each layer of boards is
+forced into place by power and held under a strong pressure, much
+slack will accumulate in an entire load, and the subsequent handling
+of the kiln cars, and the effect of the kiln-drying will loosen up the
+load until there is a tendency for the layers to telescope. And unless
+the boards are held in place rigidly and with strong pressure they
+will have a tendency to warp.
+
+    [Illustration: Fig. 49. The above illustration shows method
+    of loading kiln cars with veneer on its edges by the use of
+    the Tilting Platform.]
+
+A kiln car of edge-stacked lumber, properly piled, is made up of
+alternate solid sheets of lumber and vertical open-air spaces, so that
+the hot air and vapors rise naturally and freely through the lumber,
+drying both sides of the board evenly. The distribution of the heat
+and moisture being even and uniform, the drying process is naturally
+quickened, and there is no opportunity or tendency for the lumber to
+warp.
+
+In Figure 49 will be seen a method of loading kiln cars with veneer on
+edge by the use of a tilting platform. On the right of the
+illustration is seen a partially loaded kiln car tilted to an angle of
+45 degrees, to facilitate the placing of the veneer on the car. At
+the left is a completely loaded car ready to enter the dry kiln.
+
+Gum, poplar, and pine veneers are satisfactorily dried in this manner
+in from 8 to 24 hours.
+
+In Figure 50 will be seen method of piling lumber on the flat,
+"cross-wise" of the dry kiln when same has three tracks.
+
+    [Illustration: Fig. 50. Method of Loading lumber on its Flat,
+    cross-wise of the Dry Kiln when same has Three Tracks.]
+
+In Figure 51 will be seen another method of piling lumber on the flat,
+"cross-wise" of the dry kiln when same has three tracks.
+
+In Figure 52 will be seen method of piling lumber on the flat,
+"end-wise" of the dry kiln when same has two tracks.
+
+In Figure 53 will be seen another method of piling lumber on the flat,
+"end-wise" of the dry kiln when same has two tracks.
+
+In Figure 54 will be seen method of piling slack or tight barrel
+staves "cross-wise" of the kiln when same has three tracks.
+
+In Figure 55 will be seen another method of piling slack or tight
+barrel staves "cross-wise" of the dry kiln when same has three tracks.
+
+In Figure 56 will be seen method of piling small tub or pail staves
+"cross-wise" of the dry kiln when same has two tracks.
+
+In Figure 57 will be seen method of piling bundled staves "cross-wise"
+of the dry kiln when same has two tracks.
+
+    [Illustration: Fig. 51. Method of loading Lumber on its Flat,
+    cross-wise of the Dry Kiln when same has Three Tracks.]
+
+    [Illustration: Fig. 52. Method of loading Lumber on its Flat,
+    end-wise of the Dry Kiln by the Use of the Single-sill or
+    Dolly Truck.]
+
+    [Illustration: Fig. 53. Method of loading Lumber on its Flat,
+    end-wise of the Dry Kiln by the Use of the Double-sill
+    Truck.]
+
+    [Illustration: Fig. 54. Method of loading Kiln Car with Tight
+    or Slack Barrel Staves cross-wise of Dry Kiln.]
+
+    [Illustration: Fig. 55. Method of loading Kiln Car with Tight
+    or Slack Barrel Staves cross-wise of Dry Kiln.]
+
+    [Illustration: Fig. 56. Method of loading Kiln Car with Tub
+    or Pail Staves cross-wise of Dry Kiln.]
+
+    [Illustration: Fig. 57. Method of loading Kiln Car with
+    Bundled Staves cross-wise of Dry Kiln.]
+
+In Figure 58 will be seen method of piling shingles "cross-wise" of
+dry kiln when same has three tracks.
+
+In Figure 59 will be seen another method of piling shingles
+"cross-wise" of the dry kiln when same has three tracks.
+
+    [Illustration: Fig. 58. Method of loading Kiln Car with
+    Shingles cross-wise of Dry Kiln.]
+
+    [Illustration: Fig. 59. Method of loading Kiln Car with
+    Shingles cross-wise of Dry Kiln.]
+
+In Figure 60 will be seen method of piling shingles "end-wise" of the
+dry kiln when same has two tracks.
+
+In Figure 61 will be seen a kiln car designed for handling short tub
+or pail staves through a dry kiln.
+
+    [Illustration: Fig. 60. Car loaded with 100,000 Shingles.
+    Equipped with four long end-wise piling trucks and to go into
+    dry kiln end-wise.]
+
+    [Illustration: Fig. 61. Kiln Car designed for handling Short
+    Tub or Pail Staves through a Dry Kiln.]
+
+In Figure 62 will be seen a kiln car designed for short piece stock
+through a dry kiln.
+
+In Figure 63 will be seen a type of truck designed for the handling of
+stave bolts about a stave mill or through a steam box.
+
+In Figure 64 will be seen another type of truck designed for the
+handling of stave bolts about a stave mill or through a steam box.
+
+In Figure 65 will be seen another type of truck designed for the
+handling of stave bolts about a stave mill or through a steam box.
+
+In Figure 66 will be seen another type of truck designed for the
+handling of stave bolts about a stave mill or through a steam box.
+
+In Figure 67 will be seen another type of truck designed for the
+handling of stave bolts about a stave mill or through a steam box.
+
+In Figure 68 will be seen another type of truck designed for the
+handling of stave bolts about a stave mill or through a steam box.
+
+In Figure 69 will be seen the Regular 3-rail Transfer Car designed for
+the handling of 2-rail kiln cars which have been loaded "end-wise."
+
+In Figure 70 will be seen another type of Regular 3-rail Transfer Car
+designed for the handling of 2-rail kiln cars which have been loaded
+"end-wise."
+
+In Figure 71 will be seen a Specially-designed 4-rail Transfer Car for
+2-rail kiln cars which have been built to accommodate extra long
+material to be dried.
+
+In Figure 72 will be seen the Regular 2-rail Transfer Car designed for
+the handling of 3-rail kiln cars which have been loaded "cross-wise."
+
+In Figure 73 will be seen another type of Regular 2-rail Transfer Car
+designed for the handling of 3-rail kiln cars which have been loaded
+"cross-wise."
+
+In Figure 74 will be seen the Regular 2-rail Underslung type of
+Transfer Car designed for the handling of 3-rail kiln cars which have
+been loaded "cross-wise." Two important features in the construction
+of this transfer car make it extremely easy in its operation. It has
+extra large wheels, diameter 13-1/2 inches, and being underslung, the
+top of its rails are no higher than the other types of transfer cars.
+Note the relative size of the wheels in the illustration, yet the car
+is only about 10 inches in height.
+
+    [Illustration: Fig. 62. Kiln Car Designed for handling Short
+    Piece Stock through a Dry Kiln.]
+
+    [Illustration: Fig. 63. A Stave Bolt Truck.]
+
+    [Illustration: Fig. 64. A Stave Bolt Truck.]
+
+    [Illustration: Fig. 65. A Stave Bolt Truck.]
+
+    [Illustration: Fig. 66. A Stave Bolt Truck.]
+
+    [Illustration: Fig. 67. A Stave Bolt Truck.]
+
+    [Illustration: Fig. 68. A Stave Bolt Truck.]
+
+    [Illustration: Fig. 69. A Regular 3-Rail Transfer Truck.]
+
+    [Illustration: Fig. 70. A Regular 3-Rail Transfer Truck.]
+
+    [Illustration: Fig. 71. A Special 4-Rail Transfer Truck.]
+
+    [Illustration: Fig. 72. A Regular 2-Rail Transfer Truck.]
+
+    [Illustration: Fig. 73. A Regular 2-Rail Transfer Truck.]
+
+    [Illustration: Fig. 74. A Regular 2-Rail Underslung Transfer
+    Truck.]
+
+    [Illustration: Fig. 75. A Regular 3-Rail Underslung Transfer
+    Truck.]
+
+In Figure 75 will be seen the Regular 3-rail Underslung type of
+Transfer Car designed for the handling of 2-rail kiln cars which have
+been loaded "end-wise." This car also has the important features of
+large diameter wheels and low rail construction, which make it very
+easy in its operation.
+
+    [Illustration: Fig. 76. A Special 2-Rail Flexible Transfer
+    Truck.]
+
+In Figure 76 will be seen the Special 2-rail Flexible type of Transfer
+Car designed for the handling of 3-rail kiln cars which have been
+loaded "cross-wise." This car is equipped with double the usual number
+of wheels, and by making each set of trucks a separate unit (the front
+and rear trucks being bolted to a steel beam with malleable iron
+connection), a slight up-and-down movement is permitted, which enables
+this transfer car to adjust itself to any unevenness in the track,
+which is a very good feature.
+
+In Figure 77 will be seen the Regular Transfer Car designed for the
+handling of stave bolt trucks.
+
+In Figure 78 will be seen another type of Regular Transfer Car
+designed for the handling of stave bolt trucks.
+
+In Figure 79 will be seen a Special Transfer Car designed for the
+handling of stave bolt trucks.
+
+    [Illustration: Fig. 77. A Regular Transfer Car for handling
+    Stave Bolt Trucks.]
+
+    [Illustration: Fig. 78. A Regular Transfer Car for handling
+    Stave Bolt Trucks.]
+
+    [Illustration: Fig. 79. A Special Transfer Car for handling
+    Stave Bolt Trucks.]
+
+In Figure 80 will be seen the Regular Channel-iron Kiln Truck designed
+for edge piling "cross-wise" of the dry kiln.
+
+In Figure 81 will be seen another type of Regular Channel-iron Kiln
+Truck designed for edge piling "cross-wise" of the dry kiln.
+
+    [Illustration: Fig. 80. A Regular Channel-iron Kiln Truck.]
+
+    [Illustration: Fig. 81. A Regular Channel-iron Kiln Truck.]
+
+In Figure 82 will be seen the Regular Channel-iron Kiln Truck designed
+for flat piling "end-wise" of the dry kiln.
+
+    [Illustration: Fig. 82. A Regular Channel-iron Kiln Truck.]
+
+    [Illustration: Fig. 83. A Regular Channel-iron Kiln Truck.]
+
+    [Illustration: Fig. 84. A Regular Single-sill or Dolly Kiln
+    Truck.]
+
+In Figure 83 will be seen the Regular Channel-iron Kiln Truck with
+I-Beam cross-pieces designed for flat piling "end-wise" of the dry
+kiln.
+
+In Figure 84 will be seen the Regular Small Dolly Kiln Truck designed
+for flat piling "end-wise" of the dry kiln.
+
+
+                     Different Types of Kiln Doors
+
+In Figure 85 will be seen the Asbestos-lined Door. The construction of
+this kiln door is such that it has no tendency to warp or twist. The
+framework is solid and the body is made of thin slats placed so that
+the slat on either side covers the open space of the other with
+asbestos roofing fabric in between. This makes a comparatively light
+and inexpensive door, and one that absolutely holds the heat. These
+doors may be built either swinging, hoisting, or sliding.
+
+    [Illustration: Fig. 85. An Asbestos-lined Kiln Door of the
+    Hinge Type.]
+
+In Figure 86 will be seen the Twin Carrier type of door hangers with
+doors loaded and rolling clear of the opening.
+
+    [Illustration: Fig. 86. Twin Carrier with Kiln Door loaded
+    and rolling clear of Opening.]
+
+    [Illustration: Fig. 87. Twin Carriers for Kiln Doors 18 to 35
+    Feet wide.]
+
+In Figure 87 will be seen the Twin Carrier for doors 18 to 35 feet
+wide, idle on a section of the track.
+
+In Figure 88 will be seen another type of carrier for kiln doors.
+
+In Figure 89 will be seen the preceding type of kiln door carrier in
+operation.
+
+In Figure 90 will be seen another type of carrier for kiln doors.
+
+In Figure 91 will be seen kiln doors seated, wood construction,
+showing 3-1/2" x 5-3/4" inch-track timbers and trusses, supported on
+4-inch by 6-inch jamb posts. "T" rail track, top and side, inclined
+shelves on which the kiln door rests. Track timber not trussed on
+openings under 12 feet wide.
+
+    [Illustration: Fig. 88. Kiln Door Carrier engaged to Door
+    Ready for lifting.]
+
+In Figure 92 will be seen kiln doors seated, fire-proof construction,
+showing 12-inch, channel, steel lintels, 2" x 2" steel angle mullions,
+track brackets bolted to the steel lintels and "T" rail track. No
+track timbers or trusses used.
+
+    [Illustration: Fig. 89. Kiln Door Carrier shown on Doors of
+    Wood Construction.]
+
+    [Illustration: Fig. 90. Kiln Door Construction with Door
+    Carrier out of Sight.]
+
+    [Illustration: Fig. 91. Kiln Door Construction. Doors Seated.
+    Wood Construction.]
+
+    [Illustration: Fig. 92. Kiln Door Construction. Doors Seated.
+    Fire-proof Construction.]
+
+
+
+
+                              SECTION XIV
+
+                   HELPFUL APPLIANCES IN KILN-DRYING
+
+
+                         The Humidity Diagram
+
+    [Illustration: Fig. 93. The United States Forest Service
+    Humidity Diagram for determination of Absolute Humidities.
+    Dew Points and Vapor Pressures; also Relative Humidities by
+    means of Wet and Dry-Bulb Thermometer, for any temperatures
+    and change in temperature.]
+
+Some simple means of determining humidities and changes in humidity
+brought about by changes in temperature in the dry kiln without the
+use of tables is almost a necessity. To meet this requirement the
+United States Forestry Service has devised the Humidity Diagram shown
+in Figure 93. It differs in several respects from the hydrodeiks now
+in use.
+
+The purpose of the humidity diagram is to enable the dry-kiln operator
+to determine quickly the humidity conditions and vapor pressure, as
+well as the changes which take place with changes of temperature. The
+diagram above is adapted to the direct solution of problems of this
+character without recourse to tables or mathematical calculations.
+
+The humidity diagram consists of two distinct sets of curves on the
+same sheet. One set, the convex curves, is for the determination of
+relative humidity of wet-and-dry-bulb hygrometer or psychrometer; the
+other, the concave curves, is derived from the vapor pressures and
+shows the amount of moisture per cubic foot at relative humidities and
+temperatures when read at the dew-point. The latter curves, therefore,
+are independent of all variables affecting the wet-bulb readings. They
+are proportional to vapor pressures, not to density, and, therefore,
+may be followed from one temperature to another with correctness. The
+short dashes show the correction (increase or decrease) which is
+necessary in the relative humidity, read from the convex curves, with
+an increase or decrease from the normal barometric pressure of 30
+inches, for which the curves have been plotted. This correction,
+except for very low temperatures, is so small that it may usually be
+disregarded.
+
+The ordinates, or vertical distances, are relative humidity expressed
+in per cent of saturation, from 0 per cent at the bottom to 100 per
+cent at the top. The abscissae, or horizontal distances, are
+temperatures in degrees Fahrenheit from 30 degrees below zero, at the
+left, to 220 degrees above, at the right.
+
+
+                            Examples of Use
+
+The application of the humidity diagram can best be understood by
+sample problems. These problems also show the wide range of conditions
+to which the diagram will apply.
+
+     EXAMPLE 1. To find the relative humidity by use of
+     wet-and-dry-bulb hygrometer or psychrometer:
+
+     Place the instrument in a strong circulation of air, or wave
+     it to and fro. Read the temperature of the dry bulb and the
+     wet, and subtract. Find on the horizontal line the
+     temperature shown by the dry-bulb thermometer. Follow the
+     vertical line from this point till it intersects with the
+     convex curve marked with the difference between the wet and
+     dry readings. The horizontal line passing through this
+     intersection will give the relative humidity.
+
+     Example: Dry bulb 70 deg., wet bulb 62 deg., difference 8 deg.. Find 70 deg.
+     on the horizontal line of temperature. Follow up the
+     vertical line from 70 deg. until it intersects with the convex
+     curve marked 8 deg.. The horizontal line passing through this
+     intersection shows the relative humidity to be 64 per cent.
+
+     EXAMPLE 2. To find how much water per cubic foot is
+     contained in the air:
+
+     Find the relative humidity as in example 1. Then the nearest
+     concave curve gives the weight of water in grains per cubic
+     foot when the air is cooled to the dew-point. Using the same
+     quantities as in example 1, this will be slightly more than
+     5 grains.
+
+     EXAMPLE 3. To find the amount of water required to saturate
+     air at a given temperature:
+
+     Find on the top line (100 per cent humidity) the given
+     temperature; the concave curve intersecting at or near this
+     point gives the number of grains per cubic foot.
+     (Interpolate, if great accuracy is desired.)
+
+     EXAMPLE 4. To find the dew-point:
+
+     Obtain the relative humidity as in example 1. Then follow up
+     parallel to the nearest concave curve until the top
+     horizontal (indicating 100 per cent relative humidity) is
+     reached. The temperature on this horizontal line at the
+     point reached will be the dew-point.
+
+     Example: Dry bulb 70 deg., wet bulb 62 deg.. On the vertical line
+     for 70 deg. find the intersection with the hygrometer (convex)
+     curve for 8 deg.. This will be found at nearly 64 per cent
+     relative humidity. Then follow up parallel with the vapor
+     pressure (concave) curve marked 5 grains to its intersection
+     at the top of the chart with the 100 per cent humidity line.
+     This gives the dew-point as 57 deg..
+
+     EXAMPLE 5. To find the change in the relative humidity
+     produced by a change in temperature:
+
+     Example: The air at 70 deg. Fahr. is found to contain 64 per
+     cent humidity; what will be its relative humidity if heated
+     to 150 deg. Fahr.? Starting from the intersection of the
+     designated humidity and temperature coordinates, follow the
+     vapor-pressure curve (concave) until it intersects the 150 deg.
+     temperature ordinate. The horizontal line then reads 6 per
+     cent relative humidity. The same operation applies to
+     reductions in temperature. In the above example what is the
+     humidity at 60 deg.? Following parallel to the same curve in the
+     opposite direction until it intersects the 60 deg. ordinate
+     gives 90 per cent; at 57 deg. it becomes 100 per cent, reaching
+     the dew-point.
+
+     EXAMPLE 6. To find the amount of condensation produced by
+     lowering the temperature:
+
+     Example: At 150 deg. the wet bulb reads 132 deg.. How much water
+     would be condensed if the temperature were lowered to 70 deg.?
+     The intersection of the hygrometer curve for 18 deg. (150 deg.-132 deg.)
+     with temperature line for 150 deg. shows a relative humidity of
+     60 per cent. The vapor-pressure curve (concave) followed up
+     to the 100 per cent relative humidity line shows 45 grains
+     per cubic foot at the dew-point, which corresponds to a
+     temperature of 130 deg.. At 70 deg. it is seen that the air can
+     contain but 8 grains per cubic foot (saturation).
+     Consequently, there will be condensed 45 minus 8, or 37
+     grains per cubic foot of space measured at the dew-point.
+
+     EXAMPLE 7. To find the amount of water required to produce
+     saturation by a given rise in temperature:
+
+     Example: Take the values given in example 5. The air at the
+     dew-point contains slightly over 5 grains per cubic foot. At
+     150 deg. it is capable of containing 73 grains per cubic foot.
+     Consequently, 73-5=68 grains of water which can be
+     evaporated per cubic foot of space at the dew-point when the
+     temperature is raised to 150 deg.. But the latent heat necessary
+     to produce evaporation must be supplied in addition to the
+     heat required to raise the air to 150 deg..
+
+     EXAMPLE 8. To find the amount of water evaporated during a
+     given change of temperature and humidity:
+
+     Example: At 70 deg. suppose the humidity is found to be 64 per
+     cent and at 150 deg. it is found to be 60 per cent. How much
+     water has been evaporated per cubic foot of space? At 70 deg.
+     temperature and 64 per cent humidity there are 5 grains of
+     water present per cubic foot at the dew-point (example 2).
+     At 150 deg. and 60 per cent humidity there are 45 grains
+     present. Therefore, 45-5=40 grains of water which have been
+     evaporated per cubic foot of space, figuring all volumes at
+     the dew-point.
+
+     EXAMPLE 9. To correct readings of the hygrometer for changes
+     in barometric pressure:
+
+     A change of pressure affects the reading of the wet bulb.
+     The chart applies at a barometric pressure of 30 inches,
+     and, except for great accuracy, no correction is generally
+     necessary.
+
+     Find the relative humidity as usual. Then look for the
+     nearest barometer line (indicated by dashes). At the end of
+     each barometer line will be found a fraction which
+     represents the proportion of the relative humidity already
+     found, which must be added or subtracted for a change in
+     barometric pressure. If the barometer reading is less than
+     30 inches, add; if greater than 30 inches, subtract. The
+     figures given are for a change of 1 inch; for other changes
+     use proportional amounts. Thus, for a change of 2 inches use
+     twice the indicated ratio; for half an inch use half, and so
+     on.
+
+     Example: Dry bulb 67 deg., wet bulb 51 deg., barometer 28 inches.
+     The relative humidity is found, by the method given in
+     example 1, to equal 30 per cent. The barometric line--gives
+     a value of 3/100H for each inch of change. Since the
+     barometer is 2 inches below 30, multiply 3/100H by 2, giving
+     6/100H. The correction will, therefore, be 6/100 of 30,
+     which equals 1.8. Since the barometer is below 30, this is
+     to be added, giving a corrected relative humidity of 31.8
+     per cent.
+
+     This has nothing to do with the vapor pressure (concave)
+     curves, which are independent of barometric pressure, and
+     consequently does not affect the solution of the previous
+     problems.
+
+     EXAMPLE 10. At what temperature must the condenser be
+     maintained to produce a given humidity?
+
+     Example: Suppose the temperature in the drying room is to be
+     kept at 150 deg. Fahr., and a humidity of 80 per cent is
+     desired. If the humidity is in excess of 80 per cent the air
+     must be cooled to the dew-point corresponding to this
+     condition (see example 4), which in this case is 141.5 deg..
+
+     Hence, if the condenser cools the air to this dew point the
+     required condition is obtained when the air is again heated
+     to the initial temperature.
+
+     EXAMPLE 11. Determination of relative humidity by the
+     dew-point:
+
+     The quantity of moisture present and relative humidity for
+     any given temperature may be determined directly and
+     accurately by finding the dew-point and applying the concave
+     (vapor-pressure) curves. This does away with the necessity
+     for the empirical convex curves and wet-and-dry-bulb
+     readings. To find the dew-point some form of apparatus,
+     consisting essentially of a thin glass vessel containing a
+     thermometer and a volatile liquid, such as ether, may be
+     used. The vessel is gradually cooled through the evaporation
+     of the liquid, accelerated by forcing air through a tube
+     until a haze or dimness, due to condensation from the
+     surrounding air, first appears upon the brighter outer
+     surface of the glass. The temperature at which the haze
+     first appears is the dew-point. Several trials should be
+     made for this temperature determination, using the average
+     temperature at which the haze appears and disappears.
+
+     To determine the relative humidity of the surrounding air by
+     means of the dew-point thus determined, find the concave
+     curve intersecting the top horizontal (100 per cent
+     relative humidity) line nearest the dew-point temperature.
+     Follow parallel with this curve till it intersects the
+     vertical line representing the temperature of the
+     surrounding air. The horizontal line passing through this
+     intersection will give the relative humidity.
+
+     Example: Temperature of surrounding air is 80; dew-point is
+     61; relative humidity is 53 per cent.
+
+     The dew-point determination is, however, not as convenient
+     to make as the wet-and-dry-bulb hygrometer readings.
+     Therefore, the hygrometer (convex) curves are ordinarily
+     more useful in determining relative humidities.
+
+
+                             The Hygrodeik
+
+In Figure 94 will be seen the Hygrodeik. This instrument is used to
+determine the amount of moisture in the atmosphere. It is a very
+useful instrument, as the readings may be taken direct with accuracy.
+
+To find the relative humidity in the atmosphere, swing the index hand
+to the left of the chart, and adjust the sliding pointer to that
+degree of the wet-bulb thermometer scale at which the mercury stands.
+Then swing the index hand to the right until the sliding pointer
+intersects the curved line, which extends downwards to the left from
+the degree of the dry-bulb thermometer scale, indicated by the top of
+the mercury column in the dry-bulb tube.
+
+At that intersection, the index hand will point to the relative
+humidity on scale at bottom of chart (for example see Fig. 94). Should
+the temperature indicated by the wet-bulb thermometer be 60 degrees,
+and that of the dry-bulb 70 degrees, the index hand will indicate
+humidity 55 degrees, when the pointer rests on the intersecting line
+of 60 degrees and 80 degrees.
+
+
+                       The Recording Hygrometer
+
+In Figure 95 is shown the Recording Hygrometer complete with wet and
+dry bulbs, two connecting tubes and two recording pens and special
+moistening device for supplying water to the wet bulb.
+
+This equipment is designed particularly for use in connection with dry
+rooms and dry kilns and is arranged so that the recording instrument
+and the water supply bottle may be installed outside of the dry kiln
+or drying room, while the wet and dry bulbs are both installed inside
+the room or kiln at the point where it is desired to measure the
+humidity. This instrument records on a weekly chart the humidity for
+each hour of the day, during the entire week.
+
+    [Illustration: Fig. 94. The Hygrodeik.]
+
+
+                      The Registering Hygrometer
+
+In Figure 96 is shown the Registering Hygrometer, which consists of
+two especially constructed thermometers. The special feature of the
+thermometers permits placing the instrument in the dry kiln without
+entering the drying room, through a small opening, where it is left
+for about 20 minutes.
+
+    [Illustration: Fig. 95. The Recording Hygrometer, Complete
+    with Wet and Dry Bulbs. This instrument records on a weekly
+    chart the humidity for each hour of the day, during the
+    entire week.]
+
+The temperature of both the dry and wet bulbs are automatically
+recorded, and the outside temperature will not affect the thermometers
+when removed from the kiln. From these recorded temperatures, as shown
+when the instrument is removed from the kiln, the humidity can be
+easily determined from a simple form of chart which is furnished free
+by the makers with each instrument.
+
+
+                       The Recording Thermometer
+
+    [Illustration: Fig. 96. The Registering Hygrometer.]
+
+    [Illustration: Fig. 97. The Recording Thermometer.]
+
+In Figure 97 is shown the Recording Thermometer for observing and
+recording the temperatures within a dry kiln, and thus obtaining a
+check upon its operation. This instrument is constructed to record
+automatically, upon a circular chart, the temperatures prevailing
+within the drying room at all times of the day and night, and serves
+not only as a means of keeping an accurate record of the operation of
+the dry kiln, but as a valuable check upon the attendant in charge of
+the drying process.
+
+    [Illustration: Fig. 98. The Registering Thermometer.]
+
+    [Illustration: Fig. 99. The Recording Steam-Pressure Gauge.]
+
+
+                      The Registering Thermometer
+
+In Figure 98 is shown the Registering Thermometer, which is a less
+expensive instrument than that shown in Figure 97, but by its use the
+maximum and minimum temperatures in the drying room during a given
+period can be determined.
+
+
+                       The Recording Steam Gauge
+
+In Figure 99 is shown the Recording Steam Pressure Gauge, which is
+used for accurately recording the steam pressures kept in the boilers.
+This instrument may be mounted near the boilers, or may be located at
+any distance necessary, giving a true and accurate record of the
+fluctuations of the steam pressure that may take place within the
+boilers, and is a check upon both the day and night boiler firemen.
+
+
+                       The Troemroid Scalometer
+
+In Figure 100 is shown the Troemroid Scalometer. This instrument is a
+special scale of extreme accuracy, fitted with agate bearings with
+screw adjustment for balancing. The beam is graduated from 0 to 2
+ounces, divided into 100 parts, each division representing 1-50th of
+an ounce; and by using the pointer attached to the beam weight, the
+1-100th part of an ounce can be weighed.
+
+    [Illustration: Fig. 100. The Troemroid Scalometer.]
+
+The percentage table No. II has a range from one half of 1 per cent to
+30 per cent and is designed for use where extremely fine results are
+needed, or where a very small amount of moisture is present. Table
+No. III ranges from 30 per cent up to 90 per cent. These instruments
+are in three models as described below.
+
+     MODEL A. (One cylinder) ranges from 1/2 of 1 per cent to 30
+     per cent and is to be used for testing moisture contents in
+     kiln-dried and air-dried lumber.
+
+     MODEL B. (Two cylinders) ranges from 1/2 of 1 per cent up to
+     90 per cent and is to be used for testing the moisture
+     contents of kiln-dried, air-dried, and green lumber.
+
+     MODEL C. (One cylinder) ranges from 30 per cent to 90 per
+     cent and is applicable to green lumber only.
+
+=Test Samples.=--The green boards and all other boards intended for
+testing should be selected from boards of fair average quality. If
+air-dried, select one about half way up the height of the pile of
+lumber. If kiln-dried, two thirds the height of the kiln car. Do not
+remove the kiln car from the kiln until after the test. Three of four
+test pieces should be cut from near the middle of the cross-wise
+section of the board, and 1/8 to 3/16 inch thick. Remove the
+superfluous sawdust and splinters. When the test pieces are placed on
+the scale pan, be sure their weight is less than two ounces and more
+than 1-3/4 ounces. If necessary, use two or more broken pieces. It is
+better if the test pieces can be cut off on a fine band saw.
+
+=Weighing.=--Set the base of the scale on a level surface and accurately
+balance the scale beam. Put the test pieces on the scale pan and note
+their weight on the lower edge of the beam. Set the indicator point on
+the horizontal bar at a number corresponding to this weight, which may
+be found on the cylinder at the top of the table.
+
+Dry the test pieces on the Electric Heater (Fig. 101) 30 to 40
+minutes, or on the engine cylinder two or three hours. Weigh them at
+once and note the weight. Then turn the cylinder up and at the left of
+it under the small pointer find the number corresponding to this
+weight. The percentage of moisture lost is found directly under
+pointer on the horizontal bar first mentioned. The lower portion on
+the cylinder Table No. II is an extension of the upper portion, and
+is manipulated in the same manner except that the bottom line of
+figures is used for the first weight, and the right side of cylinder
+for second weight. Turn the cylinder down instead of up when using it.
+
+
+                        Examples (Test Pieces)
+
+     MODEL A. Table No. II, Kiln-dried or Air-dried Lumber:
+
+     If first weight is 90-1/2 and the second weight is 87, the
+     cylinder table will show the board from which the test
+     pieces were taken had a moisture content of 3.8 per cent.
+
+     MODEL B. Tables No. II and III, Air-dried (also Green and
+     Kiln-dried) Lumber.
+
+     If the first weight on lower cylinder is 97 and the second
+     weight is 76, the table will show 21.6 per cent of moisture.
+
+     MODEL C. Table III, Green Lumber:
+
+     If the first weight is 94 and the second weight is 51, the
+     table shows 45.8 per cent of moisture.
+
+
+                 Keep Records of the Moisture Content
+
+=Saw Mills.=--Should test and mark each pile of lumber when first piled
+in the yard, and later when sold it should be again tested and the two
+records given to the purchaser.
+
+=Factories.=--Should test and mark the lumber when first received, and
+if piled in the yard to be kiln-dried later, it should be tested
+before going into the dry kiln, and again before being removed, and
+these records placed on file for future reference.
+
+Kiln-dried lumber piled in storage rooms (without any heat) will
+absorb 7 to 9 per cent of moisture, and even when so stored should be
+tested for moisture before being manufactured into the finished
+product.
+
+Never work lumber through the factory that has more than 5 or 6 per
+cent of moisture or less than 3 per cent.
+
+Dry storage rooms should be provided with heating coils and properly
+ventilated.
+
+Oak or any other species of wood that shows 25 or 30 per cent of
+moisture when going into the dry kiln, will take longer to dry than it
+would if it contained 15 to 20 per cent, therefore the importance of
+testing before putting into the kiln as well as when taking it out.
+
+
+                          The Electric Heater
+
+In Figure 101 is shown the Electric Heater. This heater is especially
+designed to dry quickly the test pieces for use in connection with the
+Scalometer (see Fig. 100) without charring them. It may be attached to
+any electric light socket of 110 volts direct or alternating current.
+A metal rack is provided to hold the test pieces vertically on edge.
+
+    [Illustration: Fig. 101. The Electric Heater.]
+
+Turn the test pieces over once or twice while drying.
+
+It will require from 20 minutes to one hour to remove all the moisture
+from the test pieces when placed on this heater, depending on whether
+they are cut from green, air-dried, or kiln-dried boards.
+
+Test pieces cut from softwoods will dry quicker than those cut from
+hardwoods.
+
+When the test pieces fail to show any further loss in weight, they are
+then free from all moisture content.
+
+
+
+
+                             BIBLIOGRAPHY
+
+
+AMERICAN BLOWER COMPANY, Detroit, Mich.
+
+IMRE, JAMES E., "The Kiln-drying of Gum," The United States
+Dept. of Agriculture, Division of Forestry.
+
+NATIONAL DRY KILN COMPANY, Indianapolis, Ind.
+
+PRICHARD, REUBEN P., "The Structure of the Common Woods,"
+The United States Dept. of Agriculture, Division of Forestry,
+Bulletin No. 3.
+
+ROTH, FILIBERT, "Timber," The United States Dept. of Agriculture,
+Division of Forestry, Bulletin No. 10.
+
+STANDARD DRY KILN COMPANY, Indianapolis, Ind.
+
+STURTEVANT COMPANY, B. F., Boston, Mass.
+
+TIEMAN, H. D., "The Effects of Moisture upon the Strength and
+Stiffness of Wood," The United States Dept. of Agriculture,
+Division of Forestry, Bulletin No. 70.
+
+TIEMAN, H. D., "Principles of Kiln-drying Lumber," The United
+States Dept. of Agriculture, Division of Forestry.
+
+TIEMAN, H. D., "The Theory of Drying and its Application, etc.,"
+The United States Dept. of Agriculture, Division of Forestry,
+Bulletin No. 509.
+
+THE UNITED STATES DEPT. OF AGRICULTURE, DIVISION OF FORESTRY,
+"Check List of the Forest Trees of the United States."
+
+THE UNITED STATES DEPT. OF AGRICULTURE, DIVISION OF
+FORESTRY, Bulletin No. 37.
+
+VON SCHRENK, HERMAN, "Seasoning of Timbers," The United
+States Dept. of Agriculture, Division of Forestry, Bulletin
+No. 41.
+
+WAGNER, J. B., "Cooperage," 1910.
+
+
+
+
+                               GLOSSARY
+
+
+=Abnormal.= Differing from the usual structure.
+
+=Acuminate.= Tapering at the end.
+
+=Adhesion.= The union of members of different floral whorls.
+
+=Air-seasoning.= The drying of wood in the open air.
+
+=Albumen.=  A name applied to the food store laid up outside the
+embryo in many seeds; also nitrogenous organic matter found in plants.
+
+=Alburnam.= Sapwood.
+
+=Angiosperms.= Those plants which bear their seeds within a
+pericarp.
+
+=Annual rings.= The layers of wood which are added annually to
+the tree.
+
+=Apartment kiln.= A drying arrangement of one or more rooms
+with openings at each end.
+
+=Arborescent.= A tree in size and habit of growth.
+
+
+=Baffle plate.= An obstruction to deflect air or other currents.
+
+=Bastard cut.= Tangential cut. Wood of inferior cut.
+
+=Berry.= A fruit whose entire pericarp is succulent.
+
+=Blower kiln.= A drying arrangement in which the air is blown
+through heating coils into the drying room.
+
+=Box kiln.= A small square heating room with openings in one end
+only.
+
+=Brittleness.= Aptness to break; not tough; fragility.
+
+=Burrow.= A shelter; insect's hole in the wood.
+
+
+=Calorie.=  Unit of heat; amount of heat which raises the
+temperature.
+
+=Calyx.= The outer whorl of floral envelopes.
+
+=Capillary.= A tube or vessel extremely fine or minute.
+
+=Case-harden.= A condition in which the pores of the wood are
+closed and the outer surface dry, while the inner portion is
+still wet or unseasoned.
+
+=Cavity.= A hollow place; a hollow.
+
+=Cell.= One of the minute, elementary structures comprising the
+greater part of plant tissue.
+
+=Cellulose.= A primary cell-wall substance.
+
+=Checks.= The small chinks or cracks caused by the rupture of the
+wood fibres.
+
+=Cleft.= Opening made by splitting; divided.
+
+=Coarse-grained.= Wood is coarse-grained when the annual rings
+are wide or far apart.
+
+=Cohesion.= The union of members of the same floral whorl.
+
+=Contorted.= Twisted together.
+
+=Corolla.= The inner whorl of floral envelopes.
+
+=Cotyledon.= One of the parts of the embryo performing in part the
+function of a leaf, but usually serving as a storehouse of food
+for the developing plant.
+
+=Crossers.= Narrow wooden strips used to separate the material on
+kiln cars.
+
+=Cross-grained.= Wood is cross-grained when its fibres are spiral
+or twisted.
+
+
+=Dapple.= An exaggerated form of mottle.
+
+=Deciduous.= Not persistent; applied to leaves that fall in autumn
+and to calyx and corolla when they fall off before the fruit
+develops.
+
+=Definite.= Limited or defined.
+
+=Dew-point.= The point at which water is deposited from moisture-laden
+air.
+
+=Dicotyledon.= A plant whose embryo has two opposite cotyledons.
+
+=Diffuse.= Widely spreading.
+
+=Disk.= A circular, flat, thin piece or section of the tree.
+
+=Duramen.= Heartwood.
+
+
+=Embryo.= Applied in botany to the tiny plant within the seed.
+
+=Enchinate.= Beset with prickles.
+
+=Expansion.= An enlargement across the grain or lengthwise of the
+wood.
+
+
+=Fibres.= The thread-like portion of the tissue of wood.
+
+=Fibre-saturation point.= The amount of moisture wood will imbibe,
+usually 25 to 30 per cent of its dry-wood weight.
+
+=Figure.= The broad and deep medullary rays as in oak showing
+when the timber is cut into boards.
+
+=Filament.= The stalk which supports the anther.
+
+=Fine-grained.= Wood is fine-grained when the annual rings are
+close together or narrow.
+
+
+=Germination.= The sprouting of a seed.
+
+=Girdling.= To make a groove around and through the bark of a
+tree, thus killing it.
+
+=Glands.= A secreting surface or structure; a protuberance having
+the appearance of such an organ.
+
+=Glaucous.= Covered or whitened with a bloom.
+
+=Grain.= Direction or arrangement of the fibres in wood.
+
+=Grubs.= The larvae of wood-destroying insects.
+
+=Gymnosperms.= Plants bearing naked seeds; without an ovary.
+
+
+=Habitat.= The geographical range of a plant.
+
+=Heartwood.= The central portion of tree.
+
+=Hollow-horning.= Internal checking.
+
+=Honeycombing.= Internal checking.
+
+=Hot-blast kiln.= A drying arrangement in which the air is blown
+through heating coils into the drying room.
+
+=Humidity.= Damp, moist.
+
+=Hygroscopicity.= The property of readily imbibing moisture from
+the atmosphere.
+
+
+=Indefinite.= Applied to petals or other organs when too numerous
+to be conveniently counted.
+
+=Indigenous.= Native to the country.
+
+=Involute.= A form of vernation in which the leaf is rolled inward
+from its edges.
+
+
+=Kiln-drying.= Drying or seasoning of wood by artificial heat in an
+inclosed room.
+
+
+=Leaflet.= A single division of a compound leaf.
+
+=Limb.= The spreading portion of the tree.
+
+=Lumen.= Internal space in the spring- and summer-wood fibres.
+
+
+=Median.= Situated in the middle.
+
+=Medulla.= The pith.
+
+=Medullary rays.= Rays of fundamental tissue which connect the
+pith with the bark.
+
+=Membranous.= Thin and rather soft, more or less translucent.
+
+=Midrib.= The central or main rib of a leaf.
+
+=Moist-air kiln.= A drying arrangement in which the heat is taken
+from radiating coils located inside the drying room.
+
+=Mottle.= Figure transverse of the fibres, probably caused by the
+action of wind upon the tree.
+
+
+=Non-porous.= Without pores.
+
+
+=Oblong.= Considerably longer than broad, with flowing outline.
+
+=Obtuse.= Blunt, rounded.
+
+=Oval.= Broadly elliptical.
+
+=Ovary.= The part of the pistil that contains the ovules.
+
+
+=Parted.= Cleft nearly, but not quite to the base or midrib.
+
+=Parenchyma.= Short cells constituting the pith and pulp of the
+tree.
+
+=Pericarp.= The walls of the ripened ovary, the part of the fruit
+that encloses the seeds.
+
+=Permeable.= Capable of being penetrated.
+
+=Petal.= One of the leaves of the corolla.
+
+=Pinholes.= Small holes in the wood caused by worms or insects.
+
+=Pistil.= The modified leaf or leaves which bear the ovules; usually
+consisting of ovary, style and stigma.
+
+=Plastic.= Elastic, easily bent.
+
+=Pocket kilns.= Small drying rooms with openings on one end only
+and in which the material to be dried is piled directly on the
+floor.
+
+=Pollen.= The fertilizing powder produced by the anther.
+
+=Pores.= Minute orifices in wood.
+
+=Porous.= Containing pores.
+
+=Preliminary steaming.= Subjecting wood to a steaming process
+before drying or seasoning.
+
+=Progressive kiln.= A drying arrangement with openings at both
+ends, and in which the material enters at one end and is discharged
+at the other.
+
+
+=Rick.= A pile or stack of lumber.
+
+=Rift.= To split; cleft.
+
+=Ring shake.= A large check or crack in the wood following an
+annual ring.
+
+=Roe.= A peculiar figure caused by the contortion of the woody
+fibres, and takes a wavy line parallel to them.
+
+
+=Sapwood.= The outer portions of the tree next to the bark;
+alburnam.
+
+=Saturate.= To cause to become completely penetrated or soaked.
+
+=Season checks.= Small openings in the ends of the wood caused
+by the process of drying.
+
+=Seasoning.= The process by which wood is dried or seasoned.
+
+=Seedholes.= Minute holes in wood caused by wood-destroying
+worms or insects.
+
+=Shake.= A large check or crack in wood caused by the action of
+the wind on the tree.
+
+=Shrinkage.= A lessening or contraction of the wood substance.
+
+=Skidways.= Material set on an incline for transporting lumber or
+logs.
+
+=Species.= In science, a group of existing things, associated according
+to properties.
+
+=Spermatophyta.= Seed-bearing plants.
+
+=Spring-wood.= Wood that is formed in the spring of the year.
+
+=Stamen.= The pollen-bearing organ of the flower, usually consisting
+of filament and anther.
+
+=Stigma.= That part of the pistil which receives the pollen.
+
+=Style.= That part of the pistil which connects the ovary with the
+stigma.
+
+
+=Taproot.= The main root or downward continuation of the plant
+axis.
+
+=Temporary checks.= Checks or cracks that subsequently close.
+
+=Tissue.= One of the elementary fibres composing wood.
+
+=Thunder shake.= A rupture of the fibres of the tree across the
+grain, which in some woods does not always break them.
+
+=Tornado shake.= (See Thunder shake.)
+
+=Tracheids.= The tissues of the tree which consist of vertical cells
+or vessels closed at one end.
+
+
+=Warping.= Turning or twisting out of shape.
+
+=Wind shake.= (See Thunder shake.)
+
+=Working.= The shrinking and swelling occasioned in wood.
+
+=Wormholes.= Small holes in wood caused by wood-destroying
+worms.
+
+
+=Vernation.= The arrangement of the leaves in the bud.
+
+=Whorl.= An arrangement of organs in a circle about a central axis.
+
+
+
+
+                         INDEX OF LATIN NAMES
+
+
+Abies amabalis, 21
+Abies balsamea, 20
+Abies concolor, 20
+Abies grandis, 20
+Abies magnifica, 21
+Abies nobilis, 21
+Acer macrophyllum, 69
+Acer negundo, 69
+Acer Pennsylvanicum, 70
+Acer rubrum, 69
+Acer saccharinum, 69
+Acer saccharum, 68
+Acer spicatum, 69
+AEsculus flava, 45
+AEsculus glabra, 45
+AEsculus octandra, 45
+Ailanthus glandulosa, 37
+Asimina triloba, 76
+
+
+Betula lenta, 41
+Betula lutea, 42
+Betula nigra, 43
+Betula papyrifera, 43
+Betula populifolia, 42
+Betula rubra, 43
+Buxus sempervirens, 77
+
+
+Carpinus Caroliana, 44
+Castanea Americana, 48
+Castanea chrysophylla, 49
+Castanea dentata, 48
+Castanea pumila, 48
+Castanea vesca, 48
+Castanea vulgaris, 48
+Catalpa bignonioides, 46
+Catalpa speciosa, 46
+Celtis occidentalis, 62
+Chamaecyparis Lawsonia, 18
+Chamaecyparis thyoides, 17
+Cladrastis lutea, 85
+Cornus florida, 49
+Cupressus nootkatensis, 18
+
+
+Diospyros Virginia, 77
+
+
+Evonymus atropurpureus, 82
+
+
+Fagus ferruginea, 40
+Fraxinus Americana, 37
+Fraxinus Caroliniana, 39
+Fraxinus nigra, 38
+Fraxinus Oregana, 38
+Fraxinus Pennsylvanica, 38
+Fraxinus pubescens, 38
+Fraxinus quadrangulata, 38
+Fraxinus sambucifolia, 38
+Fraxinus viridis, 38
+
+
+Gleditschia triacanthos, 66
+Gymnocladus dioicus, 49
+
+
+Hicoria alba, 64
+Hicoria glabra, 64
+Hicoria minima, 64
+Hicoria ovata, 64
+Hicoria pecan, 64
+
+
+Ilex monticolo, 65
+Ilex opaca, 64
+
+
+Juglans cinerea, 45
+Juglans nigra, 82
+Juniperus communis, 19
+Juniperus Virginiana, 18
+
+
+Larix Americana, 22
+Larix laricina, 22
+Larix occidentalis, 22
+Libocedrus decurrens, 18
+Liquidamber styraciflua, 54
+Liriodendron tulipfera, 81
+
+
+Maclura aurantiaca, 76
+Magnolia acuminata, 67
+Magnolia glauca, 67
+Magnolia tripetala, 67
+Morus rubra, 70
+
+
+Nyssa aquatica, 60
+Nyssa sylvatica, 62
+
+
+Ostrya Virginiana, 65
+Oxydendrum arboreum, 80
+
+
+Picea alba, 28
+Picea canadensis, 28
+Picea engelmanni, 28
+Picea mariana, 27
+Picea nigra, 27
+Picea rubens, 28
+Picea sitchensis, 28
+Pinus banksiana, 27
+Pinus cubensis, 26
+Pinus divaricata, 27
+Pinus enchinata, 26
+Pinus flexilis, 24
+Pinus inops, 27
+Pinus Jeffreyi, 25
+Pinus Lambertiana, 24
+Pinus monticolo, 24
+Pinus Murryana, 27
+Pinus palustris, 24
+Pinus ponderosa, 25
+Pinus resinosa, 25
+Pinus rigida, 26
+Pinus strobus, 23
+Pinus taeda, 25
+Pinus Virginiana, 27
+Platanus occidentalis, 80
+Platanus racemosa, 81
+Populus alba, 79
+Populus angulata, 77
+Populus balsamifera, 79
+Populus fremontii, 78
+Populus grandidentata, 79
+Populus heteropylla, 78
+Populus monilifera, 77
+Populus nigra italica, 79
+Populus tremuloides, 79
+Populus trichocarpa, 78
+Populus Wislizeni, 78
+Prunus Pennsylvanica, 47
+Prunus serotina, 47
+Pseudotsuga douglasii, 29
+Pseudotsuga taxifolia, 29
+Pyrus coronaria, 49
+
+
+Quercus acuminata, 73
+Quercus alba, 71
+Quercus aquatica, 73
+Quercus bicolor, 72
+Quercus chrysolepis, 76
+Quercus coccinea, 75
+Quercus digitata, 75
+Quercus durandii, 71
+Quercus falcata, 75
+Quercus garryana, 71
+Quercus ilicijolia, 74
+Quercus imbricaria, 75
+Quercus lobata, 72
+Quercus lyrata, 73
+Quercus macrocarpa, 72
+Quercus marilandica, 75
+Quercus Michauxii, 74
+Quercus minor, 74
+Quercus nigra, 75
+Quercus obtusiloda, 74
+Quercus palustris, 73
+Quercus phellos, 72
+Quercus platanoides, 72
+Quercus prinoides, 74
+Quercus prinus, 73
+Quercus pumila, 74
+Quercus rubra, 74
+Quercus tinctoria, 74
+Quercus velutina, 74
+Quercus virens, 75
+
+
+Rhamnus Caroliniana, 45
+Robinia pseudacacia, 66
+Robinia viscosa, 66
+
+
+Salix alba, 83
+Salix amygdaloides, 84
+Salix babylonica, 84
+Salix bebbiana, 84
+Salix discolor, 84
+Salix fluviatilis, 84
+Salix fragilis, 84
+Salix lucida, 84
+Salix nigra, 83
+Salix rostrata, 84
+Salix vitellina, 83
+Sassafras sassafras, 80
+Sequoia sempervirens, 19
+
+
+Taxodium distinchum, 19
+Taxus brevifolia, 30
+Thuya gigantea, 17
+Thuya occidentalis, 17
+Tilia Americana, 39
+Tilia heterophylla, 39
+Tilia pubescens, 39
+Tsuga canadensis, 21
+Tsuga mertensiana, 21
+
+
+Ulmus alata, 51
+Ulmus Americana, 50
+Ulmus crassifolia, 51
+Ulmus fulva, 51
+Ulmus pubescens, 51
+Ulmus racemosa, 50
+Umbellularia Californica, 65
+
+
+
+
+                                 INDEX
+
+
+Abele, Tree, 79
+
+Absorption of water by dry wood, 124
+
+Acacia, 66
+
+Acacia, false, 66
+
+Acacia, three-thorned, 66
+
+According to species, different kiln drying, 170
+
+Advantages in seasoning, 128
+
+Advantages of kiln-drying over air-drying, 156
+
+Affect drying, properties of wood that, 156
+
+Ailanthus, 37
+
+Air circulation, 173
+
+Air-drying, advantages of kiln-drying over, 156
+
+Alaska cedar, 18
+
+Alaska cypress, 18
+
+Alcoholic liquids, stave and heads of barrels containing, 112
+
+Almond-leaf willow, 84
+
+Ambrosia or timber beetles, 99
+
+American box, 49
+
+American elm, 50
+
+American larch, 22
+
+American linden, 39
+
+American oak, 71
+
+American red pine, 25
+
+Anatomical structure, 14
+
+Annual ring, the yearly or, 10
+
+Apartment dry kiln, 198
+
+Apple, crab, 49
+
+Apple, custard, 76
+
+Apple, wild, 49
+
+Appliances in kiln-drying, helpful, 237
+
+Arborvitae, 17
+
+Ash, 37
+
+Ash, black, 38
+
+Ash, blue, 38
+
+Ash, Carolina, 39
+
+Ash, green, 38
+
+Ash, ground, 38
+
+Ash, hoop, 38
+
+Ash-leaved maple, 69
+
+Ash, Oregon, 38
+
+Ash, red, 38
+
+Ash, white, 37
+
+Aspen, 39, 79
+
+Aspen, large-toothed, 78
+
+Aspen-leaved birch, 42
+
+Aspen, quaking, 79
+
+Atmospheric pressure, drying at, 146
+
+
+Bald Cypress, 19
+
+Ball tree, button, 80
+
+Balm of gilead, 79
+
+Balm of gilead fir, 20
+
+Balsam, 20, 79
+
+Balsam fir, 20
+
+Bark and pith, 8
+
+Bark on, round timber with, 106
+
+Barrels containing alcoholic liquids, staves and heads of, 112
+
+Barren oak, 75
+
+Bar willow, sand, 84
+
+Basket oak, 74
+
+Basswood, 39
+
+Basswood, small-leaved, 39
+
+Basswood, white, 39
+
+Bastard pine, 26
+
+Bastard spruce, 29
+
+Bay poplar, 60
+
+Bay, sweet, 67
+
+Bear oak, 74
+
+Beaver wood, 67
+
+Bebb willow, 84
+
+Bee tree, 39
+
+Beech, 40
+
+Beech, blue, 44
+
+Beech, red, 40
+
+Beech, water, 44, 80
+
+Beech, white, 40
+
+Berry, sugar, 62
+
+Beetles, ambrosia or timber, 99
+
+Big bud hickory, 64
+
+Bilsted, 54
+
+Birch, 41
+
+Birch, aspen-leaved, 42
+
+Birch, black, 41
+
+Birch, canoe, 43
+
+Birch, cherry, 41
+
+Birch, gray, 42
+
+Birch, mahogany, 41
+
+Birch, old field, 42
+
+Birch, paper, 43
+
+Birch, red, 42
+
+Birch, river, 43
+
+Birch, silver, 42
+
+Birch, sweet, 41
+
+Birch, white, 42, 43
+
+Birch, wintergreen, 41
+
+Birch, yellow, 42
+
+Bird cherry, 47
+
+Bitternut hickory, 64
+
+Black ash, 38
+
+Black birch, 41
+
+Black cherry, 47
+
+Black cottonwood, 78
+
+Black cypress, 19
+
+Black gum, 62
+
+Black hickory, 64
+
+Black jack, 75
+
+Black larch, 22
+
+Black locust, 66
+
+Black nut hickory, 64
+
+Black oak, 74
+
+Black pine, 25, 27
+
+Black spruce, 27
+
+Black walnut, 44, 82
+
+Black willow, 83
+
+Blower dry kiln, operation of, 186
+
+Blower or hot blast dry kiln, 185
+
+Blue ash, 38
+
+Blue beech, 44
+
+Blue poplar, 81
+
+Blue willow, 83
+
+Bois d'Arc, 45, 76
+
+Bolts, stave, heading and shingle, 109
+
+Borers, flat-headed, 103
+
+Borers, powder post, 105
+
+Borers, round-headed, 101
+
+Box, American, 49
+
+Box elder, 69
+
+Box dry kiln, 204
+
+Broad-leaved maple, 69
+
+Broad-leaved trees, 31
+
+Broad-leaved trees, list of most important, 37
+
+Broad-leaved trees, wood of, 31
+
+Brown hickory, 64
+
+Brown locust, 66
+
+Buckeye, 45
+
+Buckeye, fetid, 45
+
+Buckeye, Ohio, 45
+
+Buckeye, sweet, 45
+
+Buckthorne, 45
+
+Bud hickory, big, 64
+
+Bull nut hickory, 64
+
+Bull pine, 25
+
+Bur oak, 72
+
+Burning bush, 82
+
+Bush, burning, 82
+
+Bush, juniper, 18
+
+Butternut, 45
+
+Button ball tree, 80
+
+Button wood, 80
+
+
+California Redwood, 19
+
+California white pine, 25
+
+Canadian pine, 25
+
+Canary wood, 81
+
+Canoe birch, 43
+
+Canoe cedar, 17
+
+Carolina ash, 39
+
+Carolina pine, 26
+
+Carolina poplar, 77
+
+Cars, method of loading kiln, 206
+
+Catalpa, 46
+
+Cedar, 17
+
+Cedar, Alaska, 18
+
+Cedar, canoe, 17
+
+Cedar, elm, 51
+
+Cedar, ground, 19
+
+Cedar, incense, 18
+
+Cedar of the West, red, 17
+
+Cedar, Oregon, 18
+
+Cedar, pencil, 18
+
+Cedar, Port Orford, 18
+
+Cedar, red, 18, 19
+
+Cedar, white, 17, 18
+
+Cedar, yellow, 18
+
+Changes rendering drying difficult, 140
+
+Characteristics and properties of wood, 1
+
+Checking and splitting, prevention of, 129
+
+Cherry, 47
+
+Cherry birch, 41
+
+Cherry, bird, 47
+
+Cherry, black, 47
+
+Cherry, Indian, 45
+
+Cherry, red, 47
+
+Cherry, rum, 47
+
+Cherry, wild, 47
+
+Cherry, wild red, 47
+
+Chestnut, 48
+
+Chestnut, horse, 45, 65
+
+Chestnut oak, 73
+
+Chestnut oak, rock, 73
+
+Chestnut oak, scrub, 74
+
+Chinquapin, 48, 49
+
+Chinquapin oak, 73, 74
+
+Chinquapin oak, dwarf, 74
+
+Choice of drying method, 195
+
+Circassian walnut, 60
+
+Circulation, air, 173
+
+Clammy locust, 66
+
+Classes of trees, 5
+
+Cliff elm, 50
+
+Coast redwood, 19
+
+Coffee nut, 49
+
+Coffee tree, 49
+
+Color and odor of wood, 89
+
+Color, odor, weight, and figure in wood, grain, 86
+
+Composition of sap, 116
+
+Conditions and species, temperature depends on, 171
+
+Conditions favorable for insect injury, 106
+
+Conditions governing the drying of wood, 156
+
+Conditions of success in kiln-drying, 169
+
+Coniferous trees, 8
+
+Coniferous trees, wood of, 8
+
+Coniferous woods, list of important, 17
+
+Containing alcoholic liquids, staves and heads of barrels, 112
+
+Cooperage stock and wooden truss hoops, dry, 112
+
+Cork elm, 50
+
+Cotton gum, 60
+
+Cottonwood, 49, 77, 78
+
+Cottonwood, black, 78
+
+Cottonwood, swamp, 78
+
+Cow oak, 74
+
+Crab apple, 49
+
+Crab, fragrant, 49
+
+Crack willow, 84
+
+Crude products, 106
+
+Cuban pine, 26
+
+Cucumber tree, 49, 67
+
+Cup oak, mossy, 72
+
+Cup oak, over-, 72, 73
+
+Custard apple, 76
+
+Cypress, 19
+
+Cypress, Alaska, 18
+
+Cypress, bald, 19
+
+Cypress, black, 19
+
+Cypress, Lawson's, 18
+
+Cypress, pecky, 19
+
+Cypress, red, 19
+
+Cypress, white, 19
+
+
+D'Arc, Bois, 45, 76
+
+Deal, yellow, 23
+
+Demands upon soil and moisture of red gum, 56
+
+Depends on conditions and species, temperature, 171
+
+Description of the forest service kiln, theory and, 161
+
+Diagram, the uses of the humidity, 237
+
+Difference between seasoned and unseasoned wood, 121
+
+Different grains of wood, 86
+
+Different kiln-drying according to species, 170
+
+Different species, weight of kiln-dried wood of, 95
+
+Different types, kilns of, 196
+
+Different types of dry kilns, 185
+
+Different types of kiln doors, 231
+
+Difficult, changes rendering drying, 140
+
+Difficulties of drying wood, 138
+
+Distribution of water in wood, 114
+
+Distribution of water in wood, local, 114
+
+Distribution of water in wood seasonal, 115
+
+Dogwood, 49
+
+Doors, different types of kiln, 231
+
+Douglas spruce, 29
+
+Downy linden, 39
+
+Downy poplar, 78
+
+Dry cooperage stock and wooden truss hoops, 112
+
+Drying according to species, different kiln, 170
+
+Drying, advantages of kiln-drying over air, 156
+
+Drying at atmospheric pressure, 146
+
+Drying by superheated steam, 150
+
+Drying, conditions of success in kiln, 169
+
+Drying difficult, changes rendering, 140
+
+Drying gum, kiln, 180
+
+Drying, helpful appliances in kiln, 237
+
+Drying, kiln, 164, 177
+
+Drying, losses due to improper kiln, 141
+
+Drying method, choice of, 185
+
+Drying, methods of kiln, 145
+
+Drying, objects of kiln, 168
+
+Drying of green red gum, kiln, 183
+
+Drying of wood, kiln, 156
+
+Drying of wood, physical conditions governing the, 156
+
+Drying, physical properties that influence, 125
+
+Drying, properties of wood that effect, 141
+
+Drying, theory of kiln, 157
+
+Drying, underlying principles of kiln, 166
+
+Drying under pressure and vacuum, 146
+
+Drying, unsolved problems in kiln, 143
+
+Drying wood, difficulties of, 138
+
+Drying 100 lb. of green wood in the kiln, pounds of water lost, 179
+
+Dry kiln, apartment, 198
+
+Dry kiln, box, 204
+
+Dry kiln, operation of the blower, 186
+
+Dry kiln, operation of the moist-air, 192
+
+Dry kiln, moist-air or pipe, 188
+
+Dry kiln, pocket, 200
+
+Dry kiln, progressive, 196
+
+Dry kiln, requirements in a satisfactory, 160
+
+Dry kilns, different types of, 185
+
+Dry kiln specialties, 206
+
+Dry kilns, types of, 185
+
+Dry kiln, tower, 202
+
+Dry wood, absorption of water by, 124
+
+Duck oak, 73
+
+Due to improper kiln-drying, losses, 141
+
+Dwarf chinquapin oak, 74
+
+
+Effects of Moisture on Wood, 117
+
+Elder, box, 69
+
+Electric heater, the, 250
+
+Elimination of stain and mildew, 136
+
+Elm, 50
+
+Elm, American, 50
+
+Elm, cedar, 51
+
+Elm, cliff, 50
+
+Elm, cork, 50
+
+Elm, hickory, 50
+
+Elm, moose, 51
+
+Elm, red, 51
+
+Elm, rock, 50
+
+Elm, slippery, 51
+
+Elm, water, 50
+
+Elm, winged, 51
+
+Elm, white, 50
+
+Enemies of wood, 98
+
+Evaporation of water, manner of, 123
+
+Evaporation, rapidity of, 124
+
+Expansion of wood, 135
+
+
+Factories, Scalometer in, 249
+
+False acacia, 66
+
+Favorable for insect injury, conditions, 106
+
+Fetid buckeye, 45
+
+Fibre saturation point in wood, 118
+
+Field birch, old, 42
+
+Field pine, old, 25, 26
+
+Figure in wood, 96
+
+Figure in wood, grain, color, odor, weight, and, 86
+
+Final steaming of gum, 182
+
+Fir, 20
+
+Fir, balm of gilead, 20
+
+Fir balsam, 20
+
+Fir, noble, 21
+
+Fir, red, 21, 29
+
+Fir tree, 20
+
+Fir, white, 20, 21
+
+Fir, yellow, 29
+
+Flat-headed borers, 103
+
+Forest service kiln, theory and description of, 161
+
+Form of the red gum, 55
+
+Fragrant crab, 49
+
+
+Gauge, the Recording Steam, 246
+
+Georgia pine, 24
+
+Gilead, balm of, 79
+
+Gilead fir, balm of, 20
+
+Ginger pine, 18
+
+Glaucous willow, 84
+
+Governing the drying of wood, physical conditions, 156
+
+Grain, color, odor, weight, and figure in wood, 86
+
+Grains of wood, different, 86
+
+Gray birch, 42
+
+Gray pine, 27
+
+Green ash, 38
+
+Green red gum, kiln-drying, 183
+
+Green wood in the kiln, pounds of water lost in drying 100 lbs., 179
+
+Ground ash, 38
+
+Ground cedar, 19
+
+Growth red gum, second, 59
+
+Gum, 52
+
+Gum, black, 62
+
+Gum, cotton, 60
+
+Gum, demands upon soil and moisture of red, 56
+
+Gum, final steaming of, 182
+
+Gum, form of red, 55
+
+Gum, kiln-drying, 180
+
+Gum, kiln-drying of green red, 183
+
+Gum, method of piling, 180
+
+Gum, preliminary steaming of, 182
+
+Gum, range of red, 55
+
+Gum, range of tupelo, 61
+
+Gum, red, 54, 79
+
+Gum, reproduction of red, 57
+
+Gum, second-growth red, 59
+
+Gum, sour, 62, 80
+
+Gum, sweet, 54, 80
+
+Gum, tolerance of the red, 56
+
+Gum, tupelo, 60
+
+Gum, uses of tupelo, 61
+
+
+Hackberry, 62
+
+Hacmatac, 22
+
+Hard maple, 68
+
+Hard pine, 26
+
+Hard pines, 24
+
+Hard pine, southern, 24
+
+Hardwoods, 37
+
+Hazel pine, 54, 60
+
+Headed borers, flat, 103
+
+Headed borers, round, 101
+
+Heading, stave and shingle bolts, 109
+
+Heads and staves of barrels containing alcoholic liquids, 112
+
+Heart hickory, white, 64
+
+Heartwood, sap and, 8
+
+Heater, the electric, 250
+
+Helpful appliances in kiln-drying, 237
+
+Hemlock, 21
+
+Hemlock spruce, 21
+
+Hickory, 63
+
+Hickory, big bud, 64
+
+Hickory, bitternut, 64
+
+Hickory, black, 64
+
+Hickory, black nut, 64
+
+Hickory, brown, 64
+
+Hickory, bull nut, 64
+
+Hickory elm, 50
+
+Hickory, mockernut, 64
+
+Hickory, pignut, 64
+
+Hickory, poplar, 81
+
+Hickory, scalybark, 64
+
+Hickory, shagbark, 64
+
+Hickory, shellbark, 64
+
+Hickory, swamp, 64
+
+Hickory, switchbud, 64
+
+Hickory, white heart, 64
+
+Holly, 64, 65
+
+Holly, mountain, 65
+
+Honey locust, 66
+
+Honey shucks, 66
+
+Hoop ash, 38
+
+Hoops, dry cooperage stock and wooden truss, 112
+
+Hop hornbeam, 65
+
+Hornbeam, 44
+
+Hornbeam, hop, 65
+
+Horse chestnut, 45, 65
+
+Hot blast or blower kiln, 185
+
+Humidity, 174
+
+Humidity diagram, uses of the, 237
+
+How to prevent insect injury, 107
+
+How wood is seasoned, 145
+
+Hygrodeik, the, 242
+
+Hygrometer, the recording, 242
+
+Hygrometer, the registering, 244
+
+
+Illinois Nut, 64
+
+Important broad-leaved trees, list of most, 37
+
+Important coniferous woods, list of, 17
+
+Impregnation methods, 151
+
+Improper kiln-drying, losses due to, 141
+
+Incense cedar, 18
+
+Indian bean, 46
+
+Indian cherry, 45
+
+Influence drying, physical properties that, 125
+
+Injury, conditions favorable for insect, 106
+
+Injury from insects, how to prevent, 107
+
+Insect injury, conditions favorable for, 106
+
+Insects, how to prevent injury from, 107
+
+Iron oak, 74
+
+Ironwood, 44, 65
+
+
+Jack, Black, 75
+
+Jack oak, 75
+
+Jack pine, 27
+
+Jersey pine, 27
+
+Juniper, 18
+
+Juniper bush, 18
+
+Juniper, red, 18
+
+Juniper, savin, 18
+
+
+Keep Records of the Moisture Content, 249
+
+Kiln, apartment dry, 198
+
+Kiln, blower or hot blast, 185
+
+Kiln, box dry, 204
+
+Kiln cars and method of loading, 206
+
+Kiln doors, different types, 231
+
+Kiln-dried wood of different species, weight of, 95
+
+Kiln-drying, 164, 177
+
+Kiln-drying according to species, different, 170
+
+Kiln-drying, conditions of success in, 169
+
+Kiln-drying gum, 180
+
+Kiln-drying, helpful appliances in, 237
+
+Kiln-drying, losses due to improper, 141
+
+Kiln-drying, objects of, 168
+
+Kiln-drying of green red gum, 183
+
+Kiln-drying of wood, 156
+
+Kiln-drying of wood, 156
+
+Kiln-drying over air-drying, advantages of, 156
+
+Kiln-drying, theory of, 157
+
+Kiln-drying, underlying principles of, 166
+
+Kiln-drying, unsolved problems in, 143
+
+Kiln, operation of the blower dry, 186
+
+Kiln, operation of the moist-air dry, 192
+
+Kiln, pipe or moist-air dry, 188
+
+Kiln, pocket dry, 200
+
+Kiln, progressive dry, 196
+
+Kiln, requirements in a satisfactory dry, 160
+
+Kilns, different types of dry, 185
+
+Kilns of different types, 196
+
+Kiln specialties, dry, 206
+
+Kiln, theory and description of the forest service, 161
+
+Kilns, types of dry, 185
+
+Kiln, tower dry, 202
+
+
+Land Spruce, Tide, 28
+
+Larch, 22
+
+Larch, American, 22
+
+Larch, black, 22
+
+Larch, western, 22
+
+Large-toothed aspen, 79
+
+Laurel, 65
+
+Laurel oak, 75
+
+Lawson's cypress, 18
+
+Leaf pine, long-, 24
+
+Leaf pine, short-, 26
+
+Leaf willow, long, 84
+
+Leaved basswood, small, 39
+
+Leaved birch, aspen, 42
+
+Leaved maple, ash, 69
+
+Leaved maple, broad, 69
+
+Leaved maple, silver, 69
+
+Leaved trees, broad, 31
+
+Leaved trees, list of most important broad, 37
+
+Leaved trees, wood of broad, 31
+
+Leverwood, 65
+
+Life, tree of, 17
+
+Lime tree, 39
+
+Lin, 39
+
+Linden, 39
+
+Linden, American, 39
+
+Linden, downy, 39
+
+Liquidamber, 54
+
+Liquids, staves and heads of barrels containing alcoholic, 112
+
+List of important coniferous trees, 17
+
+List of most important broad-leaved trees, 37
+
+Live oak, 75, 76
+
+Loading, kiln cars and method of, 206
+
+Loblolly pine, 25
+
+Local distribution of water in wood, 114
+
+Locust, 66
+
+Locust, black, 66
+
+Locust, brown, 66
+
+Locust, clammy, 66
+
+Locust, honey, 66
+
+Locust, sweet, 66
+
+Locust, yellow, 66
+
+Lodge-pole pine, 27
+
+Lombardy poplar, 79
+
+Long-leaf pine, 24
+
+Long-leaf willow, 84
+
+Long-straw pine, 24
+
+Losses due to improper kiln-drying, 141
+
+Lost in kiln-drying 100 lb. green wood in the kiln, pounds of water, 179
+
+
+Magnolia, 67
+
+Magnolia, small, 67
+
+Magnolia, swamp, 67
+
+Mahogany, birch, 41
+
+Mahogany, white, 45
+
+Manner of evaporation of water, 123
+
+Maple, 67
+
+Maple, ash-leaved, 69
+
+Maple, broad-leaved, 69
+
+Maple, hard, 68
+
+Maple, mountain, 69
+
+Maple, Oregon, 69
+
+Maple, red, 69
+
+Maple, rock, 68
+
+Maple, silver, 69
+
+Maple, silver-leaved, 69
+
+Maple, soft, 69
+
+Maple, striped, 70
+
+Maple, sugar, 68
+
+Maple, swamp, 69
+
+Maple, water, 69
+
+Maple, white, 69
+
+Maul oak, 75, 76
+
+Meadow pine, 26
+
+Method, choice of drying, 195
+
+Method of loading kiln cars, 206
+
+Method of piling gum, 180
+
+Methods, impregnation, 151
+
+Methods of drying, 154
+
+Mildew, elimination of stain and, 136
+
+Minute structure, 34
+
+Mockernut hickory, 64
+
+Moist-air dry kiln, operation of, 192
+
+Moist-air or pipe kiln, the, 188
+
+Moisture content, keep records of the, 249
+
+Moisture, demands upon soil and, 56
+
+Moisture on wood, effects of, 117
+
+Moose elm, 51
+
+Moose-wood, 70
+
+Mossy-cup oak, 72
+
+Most important broad-leaved trees list of, 37
+
+Mountain holly, 65
+
+Mountain maple, 69
+
+Mulberry, 70
+
+Mulberry, red, 70
+
+Myrtle, 65, 70
+
+
+Nettle Tree, 62
+
+Noble fir, 21
+
+Norway pine, 25
+
+Nut, coffee, 49
+
+Nut hickory, black, 64
+
+Nut hickory, bull, 64
+
+Nut, Illinois, 64
+
+Nyssa, 60
+
+
+Oak, 70
+
+Oak, American, 71
+
+Oak, barren, 75
+
+Oak, basket, 74
+
+Oak, bear, 74
+
+Oak, black, 74
+
+Oak, bur, 72
+
+Oak, chestnut, 73
+
+Oak, chinquapin, 73, 74
+
+Oak, cow, 74
+
+Oak, duck, 73
+
+Oak, dwarf chinquapin, 74
+
+Oak, iron, 74
+
+Oak, jack, 75
+
+Oak, laurel, 75
+
+Oak, live, 75, 76
+
+Oak, maul, 75, 76
+
+Oak, mossy-cup, 72
+
+Oak, over-cup, 72, 73
+
+Oak, peach, 72
+
+Oak, pin, 73
+
+Oak, possum, 73
+
+Oak, post, 74
+
+Oak, punk, 73
+
+Oak, red, 74, 75
+
+Oak, rock, 73
+
+Oak, rock chestnut, 73
+
+Oak, scarlet, 75
+
+Oak, scrub, 74
+
+Oak, scrub chestnut, 74
+
+Oak, shingle, 75
+
+Oak, Spanish, 75
+
+Oak, swamp post, 73
+
+Oak, swamp Spanish, 73
+
+Oak, swamp white, 72, 73
+
+Oak, water, 73
+
+Oak, western white, 71
+
+Oak, white, 71, 72
+
+Oak, willow, 72
+
+Oak, yellow, 73, 74
+
+Oak, Valparaiso, 76
+
+Objects of kiln-drying, 168
+
+Odor and color of wood, 89
+
+Odor, weight, and figure in wood, grain, color, 86
+
+Ohio buckeye, 45
+
+Old field birch, 42
+
+Old field pine, 25, 26
+
+Operation of the blower kiln, 186
+
+Operation of the moist-air kiln, 192
+
+Orange, osage, 76
+
+Oregon ash, 38
+
+Oregon cedar, 18
+
+Oregon maple, 69
+
+Oregon pine, 29
+
+Orford cedar, Port, 18
+
+Osage orange, 76
+
+Out-of-door seasoning, 154
+
+Over-cup oak, 72, 73
+
+
+Papaw, 76
+
+Paper birch, 43
+
+Peach oak, 72
+
+Pecan, 64
+
+Pecky cypress, 19
+
+Pencil cedar, 18
+
+Pepperidge, 60
+
+Perch willow, 84
+
+Persimmon, 77
+
+Peruche, 21
+
+Physical conditions governing the drying of wood, 156
+
+Physical properties that influence drying, 125
+
+Pignut hickory, 64
+
+Piling gum, methods of, 180
+
+Pine, American red, 25
+
+Pine, bastard, 26
+
+Pine, black, 25, 27
+
+Pine, bull, 25
+
+Pine, California white, 25
+
+Pine, Canadian, 25
+
+Pine, Carolina, 26
+
+Pine, Cuban, 26
+
+Pine, Georgia, 24
+
+Pine, ginger, 18
+
+Pine, gray, 27
+
+Pine, hard, 26
+
+Pine, hazel, 54, 60
+
+Pine, jack, 27
+
+Pine, Jersey, 27
+
+Pine, loblolly, 25
+
+Pine, lodge-pole, 27
+
+Pine, long-leaf, 24
+
+Pine, long-straw, 24
+
+Pine, meadow, 26
+
+Pine, Norway, 25
+
+Pine, old field, 25, 26
+
+Pine, Oregon, 29
+
+Pine, pitch, 26
+
+Pine, Puget Sound, 29
+
+Pine, pumpkin, 23, 24
+
+Pine, red, 29
+
+Pine, rosemary, 25
+
+Pine, sap, 25
+
+Pine, scrub, 27
+
+Pines, hard, 24
+
+Pine, short-leaf, 26
+
+Pine, short-straw, 25
+
+Pine, slash, 25, 26
+
+Pine, soft, 23, 24
+
+Pine, southern, 24
+
+Pine, southern hard, 24
+
+Pine, spruce, 26
+
+Pine, sugar, 24
+
+Pine, swamp, 26
+
+Pine, torch, 26
+
+Pine, Weymouth, 23
+
+Pine, western, 25
+
+Pine, western white, 25
+
+Pine, western yellow, 25
+
+Pine, white, 23, 24
+
+Pine, yellow, 24, 25, 26
+
+Pin oak, 73
+
+Pipe or moist-air kiln, 188
+
+Pitch pine, 26
+
+Pith and bark, 8
+
+Plane tree, 80
+
+Pocket dry kiln, the, 200
+
+Point in wood, the fibre saturation, 118
+
+Pole pine, lodge, 27
+
+Poplar, 67, 77, 79, 81
+
+Poplar, bay, 60
+
+Poplar, blue, 81
+
+Poplar, Carolina, 77
+
+Poplar, downy, 78
+
+Poplar, hickory, 81
+
+Poplar, Lombardy, 79
+
+Poplar, swamp, 60
+
+Poplar, white, 79, 81
+
+Poplar, yellow, 81
+
+Port Orford cedar, 18
+
+Possum oak, 73
+
+Post borers, powder, 105
+
+Post oak, 74
+
+Post oak, swamp, 73
+
+Pounds of water lost in drying 100 lb. green wood in the kiln, 179
+
+Powder post borers, 105
+
+Preliminary steaming of gum, 182
+
+Preliminary treatments, 151
+
+Pressure and vacuum, drying under, 146
+
+Pressure, drying at atmospheric, 146
+
+Prevent injury from insects, how to, 107
+
+Prevention of checking and splitting, 129
+
+Principles of kiln-drying, underlying, 166
+
+Problems in kiln-drying, unsolved, 143
+
+Products, crude, 106
+
+Products in the rough, seasoned, 112
+
+Products in the rough, unseasoned, 109
+
+Progressive dry kiln, the, 196
+
+Properties, characteristics and, 1
+
+Properties of wood, 4
+
+Properties of wood that affect drying, 141
+
+Properties that influence drying, physical, 125
+
+Puget Sound pine, 29
+
+Pumpkin pine, 23, 24
+
+Punk oak, 73
+
+Pussy willow, 84
+
+
+Quaking Aspen, 79
+
+
+Range of Red Gum, 55
+
+Range of tupelo gum, 61
+
+Rapidity of evaporation, 124
+
+Recording hygrometer, the, 242
+
+Recording steam gauge, the, 246
+
+Recording thermometer, the, 245
+
+Records of the moisture content, keep, 249
+
+Red ash, 38
+
+Red beech, 40
+
+Red birch, 43
+
+Red cedar, 18, 19
+
+Red cedar of the West, 17
+
+Red cherry, 47
+
+Red cherry, wild, 47
+
+Red cypress, 19
+
+Red elm, 51
+
+Red fir, 21, 29
+
+Red gum, 54, 79
+
+Red gum, demands upon soil and moisture of, 56
+
+Red gum, form of the, 55
+
+Red gum, kiln-drying of green, 183
+
+Red gum, range of, 55
+
+Red gum, reproduction of, 57
+
+Red gum, second-growth, 59
+
+Red gum, tolerance of, 56
+
+Red juniper, 18
+
+Red maple, 69
+
+Red mulberry, 70
+
+Red oak, 74, 75
+
+Red pine, 29
+
+Red pine, American, 25
+
+Red spruce, 28
+
+Redwood, 19, 27
+
+Redwood, California, 19
+
+Redwood, Coast, 19
+
+Registering hygrometer, the, 244
+
+Registering thermometer, the, 246
+
+Rendering drying difficult, changes, 140
+
+Reproduction of red gum, 57
+
+Requirements in a satisfactory dry kiln, 160
+
+Ring, the annual or yearly, 10
+
+River birch, 43
+
+Rock chestnut oak, 73
+
+Rock elm, 50
+
+Rock maple, 68
+
+Rock oak, 73
+
+Rosemary pine, 25
+
+Rough, seasoned products in the, 112
+
+Rough, unseasoned products in the, 109
+
+Round-headed borers, 101
+
+Round timber with bark on, 106
+
+Rum cherry, 47
+
+
+Samples for Scalometer Test, 248
+
+Sand bar willow, 84
+
+Sap and heartwood, 8
+
+Sap, composition of, 116
+
+Saplings, 108
+
+Sap pine, 25
+
+Sassafras, 80
+
+Satin walnut, 54
+
+Satisfactory dry kiln, requirements in a, 160
+
+Saturation point in wood, fibre, 118
+
+Sawmills, scalometer in, 249
+
+Savin juniper, 18
+
+Scalometer in factories, 249
+
+Scalometer in sawmills, 249
+
+Scalometer, test samples for, 248
+
+Scalometer, the troemroid, 247
+
+Scalometer, weighing with, 248
+
+Scalybark hickory, 64
+
+Scarlet oak, 75
+
+Scrub chestnut oak, 74
+
+Scrub oak, 74
+
+Scrub pine, 27
+
+Seasonal distribution of water in wood, 115
+
+Seasoned and unseasoned wood, difference between, 121
+
+Seasoned, how wood is, 145
+
+Seasoned products in the rough, 112
+
+Seasoning, advantages in, 128
+
+Seasoning is, what, 119
+
+Seasoning, out-of-door, 154
+
+Second-growth red gum, 59
+
+Sequoia, 19
+
+Service kiln, theory and description of forest, 161
+
+Shagbark hickory, 64
+
+Shellbark hickory, 64
+
+Shingle, heading and stave bolts, 109
+
+Shingle oak, 75
+
+Shining willow, 84
+
+Short-leaf pine, 26
+
+Short-straw pine, 25
+
+Shrinkage of wood, 130
+
+Shucks, honey, 66
+
+Sitka spruce, 28
+
+Silver birch, 42
+
+Silver-leaved maple, 69
+
+Silver maple, 69
+
+Slash pine, 25, 26
+
+Slippery elm, 51
+
+Small-leaved basswood, 39
+
+Small magnolia, 67
+
+Soft maple, 69
+
+Soft pine, 23, 24
+
+Soil and moisture, demands upon, 56
+
+Sorrel-tree, 80
+
+Sound pine, Puget, 29
+
+Sour gum, 62, 80
+
+Sourwood, 80
+
+Southern hard pine, 24
+
+Southern pine, 24
+
+Spanish oak, 75
+
+Spanish oak, swamp, 73
+
+Specialties, dry-kiln, 206
+
+Species, different kiln-drying according to, 170
+
+Species, temperature depends upon condition and, 171
+
+Species, weight of kiln-dried wood of different, 95
+
+Spindle tree, 82
+
+Splitting, prevention of checking and, 129
+
+Spring and summer-wood, 12
+
+Spruce, 27
+
+Spruce, bastard, 29
+
+Spruce, black, 27
+
+Spruce, Douglas, 29
+
+Spruce, hemlock, 21
+
+Spruce pine, 26
+
+Spruce, red, 28
+
+Spruce, Sitka, 28
+
+Spruce, tide-land, 28
+
+Spruce, white, 28
+
+Stain and mildew, elimination of, 136
+
+Stave, heading and shingle bolts, 109
+
+Staves and heads of barrels containing alcoholic liquids, 112
+
+Steam, drying by superheated, 150
+
+Steam gauge, the recording, 246
+
+Steaming of gum, preliminary, 182
+
+Steaming of gum, final, 182
+
+Stock and wooden truss hoops, dry cooperage, 112
+
+Straw pine, long, 24
+
+Straw pine, short, 25
+
+Striped maple, 70
+
+Structure, anatomical, 14
+
+Structure, minute, 34
+
+Structure of wood, 4
+
+Stump tree, 49
+
+Success in kiln-drying, conditions of, 169
+
+Sugar berry, 62
+
+Sugar maple, 68
+
+Sugar pine, 24
+
+Summerwood, spring and, 12
+
+Superheated steam, drying by, 150
+
+Swamp cottonwood, 78
+
+Swamp hickory, 64
+
+Swamp magnolia, 67
+
+Swamp maple, 69
+
+Swamp pine, 26
+
+Swamp poplar, 60
+
+Swamp post oak, 73
+
+Swamp Spanish oak, 73
+
+Swamp white oak, 72, 73
+
+Sweet bay, 67
+
+Sweet buckeye, 45
+
+Sweet birch, 41
+
+Sweet gum, 54, 80
+
+Sweet locust, 66
+
+Switchbud hickory, 64
+
+Sycamore, 80, 81
+
+
+Tacmahac, 79
+
+Tamarack, 22, 27, 29
+
+Temperature depends upon conditions and species, 171
+
+Test samples for scalometer, 248
+
+Theory and description of the forest service kiln, 161
+
+Theory of kiln-drying, 157
+
+Thermometer, the recording, 245
+
+Thermometer, the registering, 246
+
+Thorned acacia, three, 66
+
+Three-thorned acacia, 66
+
+Tide-land spruce, 28
+
+Timber, 1
+
+Timber beetles, ambrosia or, 99
+
+Timber with bark on, round, 106
+
+Timber worms, 103
+
+Tolerance of red gum, 56
+
+Toothed aspen, large-, 79
+
+Torch pine, 26
+
+Tower dry kiln, the, 202
+
+Treatments, preliminary, 151
+
+Tree, abele, 79
+
+Tree, bee, 39
+
+Tree, button ball, 80
+
+Tree, coffee, 49
+
+Tree, cucumber, 49, 67
+
+Tree, fir, 20
+
+Tree, lime, 39
+
+Tree, nettle, 62
+
+Tree of life, 17
+
+Tree, plane, 80
+
+Trees, broad-leaved, 31
+
+Trees, classes of, 5
+
+Trees, coniferous, 8
+
+Trees, list of important coniferous, 17
+
+Trees, list of most important broad-leaved, 37
+
+Tree, sorrel, 80
+
+Tree, spindle, 82
+
+Tree, stump, 49
+
+Trees, wood of broad-leaved, 31
+
+Trees, wood of the coniferous, 8
+
+Tree, tulip, 81
+
+Tree, umbrella, 67
+
+Troemroid Scalometer, the, 247
+
+Truss hoops, dry cooperage stock and, 112
+
+Tulip tree, 81
+
+Tulip wood, 67, 81
+
+Tupelo, 82
+
+Tupelo gum, 60
+
+Tupelo gum, range of, 61
+
+Tupelo gum, uses of, 61
+
+Types of dry kilns, different, 185
+
+Types of kiln doors, different, 231
+
+Types, kilns of different, 196
+
+
+Umbrella Tree, 67
+
+Underlying principles of kiln-drying, 166
+
+Unseasoned products in the rough, 109
+
+Unseasoned wood, difference between seasoned and, 121
+
+Unsolved problems in kiln-drying, 143
+
+Uses of the humidity diagram, 237
+
+Uses of tupelo gum, 61
+
+
+Vacuum, Drying under Pressure and, 146
+
+Valparaiso oak, 76
+
+Virgilia, 85
+
+
+Wahoo, 51, 82
+
+Walnut, 45, 82
+
+Walnut, black, 44, 82
+
+Walnut, circassian, 60
+
+Walnut, satin, 54
+
+Walnut, white, 45, 83
+
+Water beech, 44, 80
+
+Water by dry wood, absorption of, 124
+
+Water elm, 50
+
+Water in wood, 114
+
+Water in wood, distribution of, 114
+
+Water in wood, local distribution of, 114
+
+Water in wood, seasonal distribution of, 115
+
+Water lost in drying 100 lb. of green wood in the kiln, pounds of, 179
+
+Water, manner of evaporation of, 123
+
+Water maple, 69
+
+Water oak, 73
+
+Weeping willow, 84
+
+Weighing with scalometer, 248
+
+Weight, and figure in wood, grain, color, odor, 86
+
+Weight of kiln-dried wood of different species, 95
+
+Weight of wood, 91
+
+Western larch, 22
+
+Western pine, 25
+
+Western white oak, 71
+
+Western white pine, 25
+
+Western yellow pine, 25
+
+West, red cedar of the, 17
+
+Weymouth pine, 23
+
+What seasoning is, 119
+
+White ash, 37
+
+White basswood, 39
+
+White beech, 40
+
+White birch, 42, 43
+
+White cedar, 17, 18
+
+White cypress, 19
+
+White elm, 50
+
+White fir, 20, 21
+
+White heart hickory, 64
+
+White mahogany, 45
+
+White maple, 69
+
+White oak, 71, 72
+
+White oak, swamp, 72, 73
+
+White oak, western, 71
+
+White pine, 23, 24
+
+White pine, California, 25
+
+White pine, western, 25
+
+White poplar, 79, 81
+
+White spruce, 28
+
+White walnut, 45, 83
+
+White willow, 83
+
+Whitewood, 39, 81, 83
+
+Wild apple, 49
+
+Wild cherry, 47
+
+Wild red cherry, 47
+
+Willow, 83
+
+Willow, almond-leaf, 84
+
+Willow, bebb, 84
+
+Willow, black, 83
+
+Willow, blue, 83
+
+Willow, crack, 84
+
+Willow, glaucous, 84
+
+Willow, long-leaf, 84
+
+Willow, oak, 72
+
+Willow, perch, 84
+
+Willow, pussy, 84
+
+Willow, sand bar, 84
+
+Willow, shining, 84
+
+Willow, weeping, 84
+
+Willow, white, 83
+
+Willow, yellow, 83
+
+Winged elm, 51
+
+Wintergreen birch, 41
+
+Wood, absorption of water by dry, 124
+
+Wood, beaver, 67
+
+Wood, canary, 81
+
+Wood, characteristics and properties of, 1
+
+Wood, color and odor of, 89
+
+Wood, different grains of, 86
+
+Wood, difference between seasoned and unseasoned, 121
+
+Wood, difficulties of drying, 138
+
+Wood, distribution of water in, 114
+
+Wood, effects of moisture on, 117
+
+Wood, enemies of, 98
+
+Wood, expansion of, 135
+
+Wood, figure in, 96
+
+Wood, grain, color, odor, weight, and figure in, 86
+
+Wood, how seasoned, 145
+
+Wood in the kiln, pounds of water lost in drying 100 lb. of green, 179
+
+Wood, iron, 65
+
+Wood, kiln-drying of, 156
+
+Wood, lever, 65
+
+Wood, local distribution of water in, 114
+
+Wood, moose, 70
+
+Wood, of broad-leaves trees, 31
+
+Wood of different species, weight of kiln-dried, 95
+
+Wood of coniferous trees, 8
+
+Wood, physical conditions governing the drying of, 156
+
+Wood, properties of, 4
+
+Wood, seasonal distribution of water in, 115
+
+Wood, shrinkage of, 130
+
+Woods, list of important coniferous, 17
+
+Wood, spring and summer, 12
+
+Wood, structure of, 4
+
+Wood that effect drying, properties of, 141
+
+Wood, the fibre saturation point in, 118
+
+Wood, tulip, 67, 81
+
+Wood, water in, 114
+
+Wood, weight of, 89
+
+Wood, white, 81, 83
+
+Wood, yellow, 85
+
+Wooden truss hoops, dry cooperage, stock and, 112
+
+Worms, timber, 103
+
+
+Yearly Ring, the Annual of, 10
+
+Yellow birch, 42
+
+Yellow cedar, 18
+
+Yellow deal, 23
+
+Yellow fir, 29
+
+Yellow locust, 66
+
+Yellow oak, 73, 74
+
+Yellow pine, 24, 25, 26
+
+Yellow pine, western, 25
+
+Yellow poplar, 81
+
+Yellow willow, 83
+
+Yellow wood, 85
+
+Yew, 29, 30
+
+
+
+
+                        D. VAN NOSTRAND COMPANY
+                             25 PARK PLACE
+                               NEW YORK
+
+
+                          SHORT-TITLE CATALOG
+                                  OF
+                     Publications and Importations
+                                  OF
+                      SCIENTIFIC AND ENGINEERING
+                                 BOOKS
+
+                            [Illustration]
+
+                          This list includes
+    the technical publications of the following English publishers:
+
+            SCOTT, GREENWOOD & CO. JAMES MUNRO & CO., Ltd.
+          CONSTABLE & COMPANY, Ltd. TECHNICAL PUBLISHING CO.
+                 ELECTRICIAN PRINTING & PUBLISHING CO.
+
+         for whom D. Van Nostrand Company are American agents.
+
+
+
+
+                                                      JULY, 1917
+
+                          SHORT-TITLE CATALOG
+                                OF THE
+                     Publications and Importations
+                                  OF
+                        D. VAN NOSTRAND COMPANY
+                         25 PARK PLACE, N. Y.
+
+             _Prices marked with an asterisk (*) are NET._
+
+          _All bindings are in cloth unless otherwise noted._
+
+
+Abbott, A. V. The Electrical Transmission of Energy          8vo, *$5 00
+
+---- A Treatise on Fuel. (Science Series No. 9)             16mo,   0 50
+
+---- Testing Machines. (Science Series No. 74.)             16mo,   0 50
+
+Adam, P. Practical Bookbinding. Trans. by T. E. Maw         12mo,  *2 50
+
+Adams, H. Theory and Practice in Designing                   8vo,  *2 50
+
+Adams, H. C. Sewage of Sea Coast Towns                       8vo,  *2 00
+
+Adams, J. W. Sewers and Drains for Populous Districts        8vo,   2 50
+
+Adler, A. A. Theory of Engineering Drawing                   8vo,  *2 00
+
+---- Principles of Parallel Projecting-line Drawing          8vo,  *1 00
+
+Aikman, C. M. Manures and the Principles of Manuring         8vo,   2 50
+
+Aitken, W. Manual of the Telephone                           8vo,  *8 00
+
+d'Albe, E. E. F., Contemporary Chemistry                    12mo,  *1 25
+
+Alexander, J. H. Elementary Electrical Engineering          12mo,   2 00
+
+Allan, W. Strength of Beams Under Transverse Loads.
+  (Science Series No. 19.)                                  16mo,   0 50
+
+---- Theory of Arches. (Science Series No. 11)              16mo,
+
+Allen, H. Modern Power Gas Producer Practice and
+  Applications.                                             12mo,  *2 50
+
+Anderson, J. W. Prospector's Handbook                       12mo,   1 50
+
+Andes, L. Vegetable Fats and Oils                            8vo,  *4 00
+
+---- Animal Fats and Oils. Trans. by C. Salter               8vo,  *4 00
+
+---- Drying Oils, Boiled Oil, and Solid and Liquid Driers    8vo,  *5 00
+
+---- Iron Corrosion, Anti-fouling and Anti-corrosive
+  Paints. Trans. by C. Salter                                8vo,  *4 00
+
+---- Oil Colors, and Printers' Ink. Trans. by A. Morris
+  and H. Robson                                              8vo,  *2 50
+
+---- Treatment of Paper for Special Purposes. Trans.
+  by C. Salter                                              12mo,  *2 50
+
+Andrews, E. S. Reinforced Concrete Construction             12mo,  *1 50
+
+---- Theory and Design of Structures                         8vo,  *3 50
+
+---- Further Problems in the Theory and Design
+  of Structures                                              8vo,  *2 50
+
+---- The Strength of Materials                               8vo,  *4 00
+
+Andrews, E. S., and Heywood, H. B. The Calculus
+  for Engineers.                                            12mo,  *1 50
+
+Annual Reports on the Progress of Chemistry. Twelve
+  Volumes now ready. Vol. I., 1904, Vol. XII., 1914    8vo, each,  *2 00
+
+Argand, M. Imaginary Quantities. Translated from the
+  French by A. S. Hardy. (Science Series No. 52.)           16mo,   0 50
+
+Armstrong, R., and Idell, F. E. Chimneys for Furnaces
+  and Steam Boilers. (Science Series No. 1.)                16mo,   0 50
+
+Arnold, E. Armature Windings of Direct-Current Dynamos.
+  Trans. by F. B. DeGress                                    8vo,  *2 00
+
+Asch, W., and Asch, D. The Silicates in Chemistry
+  and Commerce                                               8vo,  *6 00
+
+Ashe, S. W., and Kelley, J. D. Electric Railways.
+  Theoretically and Practically Treated. Vol. I.
+  Rolling Stock                                             12mo,  *2 50
+
+Ashe, S. W. Electric Railways. Vol. II. Engineering
+  Preliminaries and Direct Current Sub-Stations             12mo,  *2 50
+
+---- Electricity: Experimentally and Practically Applied    12mo,  *2 00
+
+Ashley, R. H. Chemical Calculations                         12mo,  *2 00
+
+Atkins, W. Common Battery Telephony Simplified              12mo,  *1 25
+
+Atkinson, A. A. Electrical and Magnetic Calculations         8vo,  *1 50
+
+Atkinson, J. J. Friction of Air in Mines. (Science
+  Series No. 14.)                                           16mo,   0 50
+
+Atkinson, J. J., and Williams, Jr., E. H. Gases Met
+  with in Coal Mines. (Science Series No. 13.)              16mo,   0 50
+
+Atkinson, P. The Elements of Electric Lighting              12mo,   1 00
+
+---- The Elements of Dynamic Electricity and Magnetism      12mo,   2 00
+
+---- Power Transmitted by Electricity                       12mo,   2 00
+
+Auchincloss, W. S. Link and Valve Motions Simplified         8vo,  *1 50
+
+Austin, E. Single Phase Electric Railways                    4to,  *5 00
+
+Austin and Cohn. Pocketbook of Radiotelegraphy      (_In Press._)
+
+Ayrton, H. The Electric Arc                                  8vo,  *5 00
+
+
+Bacon, F. W. Treatise on the Richards Steam-Engine
+  Indicator                                                 12mo,   1 00
+
+Bailey, R. D. The Brewers' Analyst                           8vo,  *5 00
+
+Baker, A. L. Quaternions                                     8vo,  *1 25
+
+---- Thick-Lens Optics                                      12mo,  *1 50
+
+Baker, Benj. Pressure of Earthwork. (Science
+  Series No. 56.)                                           16mo,
+
+Baker, G. S. Ship Form, Resistance and Screw Propulsion      8vo,  *4 50
+
+Baker, I. O. Levelling. (Science Series No. 91.)            16mo,   0 50
+
+Baker, M. N. Potable Water. (Science Series No. 61.)        16mo,   0 50
+
+---- Sewerage and Sewage Purification. (Science
+  Series No. 18.)                                           16mo,   0 50
+
+Baker, T. T. Telegraphic Transmission of Photographs        12mo,  *1 25
+
+Bale, G. R. Modern Iron Foundry Practice. Two Volumes.      12mo.
+    Vol. I. Foundry Equipment, Materials Used                      *2 50
+    Vol. II. Machine Moulding and Moulding Machines                *1 50
+
+Ball, J. W. Concrete Structures in Railways                  8vo,  *2 50
+
+Ball, R. S. Popular Guide to the Heavens                     8vo,  *5 00
+
+---- Natural Sources of Power. (Westminster Series.)         8vo,  *2 00
+
+Ball, W. V. Law Affecting Engineers                          8vo,  *3 50
+
+Bankson, Lloyd. Slide Valve Diagrams. (Science
+  Series No. 108.).                                         16mo,   0 50
+
+Barham, G. B. Development of the Incandescent Electric
+  Lamp                                                       8vo,  *2 00
+
+Barker, A. F. Textiles and Their Manufacture.
+  (Westminster Series.)                                      8vo,   2 00
+
+Barker, A. F., and Midgley, E. Analysis of Textile Fabrics   8vo,   3 00
+
+Barker, A. H. Graphic Methods of Engine Design              12mo,  *1 50
+
+---- Heating and Ventilation                                 4to,  *8 00
+
+Barnard, J. H. The Naval Militiaman's Guide        16mo, leather,   1 00
+
+Barnard, Major J. G. Rotary Motion. (Science
+  Series No. 90.)                                           16mo,   0 50
+
+Barnes, J. B. Elements of Military Sketching                16mo,  *0 60
+
+Barrus, G. H. Engine Tests                                   8vo,  *4 00
+
+Barwise, S. The Purification of Sewage                      12mo,   3 50
+
+Baterden, J. R. Timber. (Westminster Series.)                8vo,  *2 00
+
+Bates, E. L., and Charlesworth, F. Practical Mathematics
+  and Geometry                                              12mo,
+    Part I. Preliminary and Elementary Course                      *1 50
+    Part II. Advanced Course                                       *1 50
+
+---- Practical Mathematics                                  12mo,  *1 50
+
+---- Practical Geometry and Graphics                        12mo,  *2 00
+
+Batey, J. The Science of Works Management                   12mo,  *1 50
+
+---- Steam Boilers and Combustion                           12mo,  *1 50
+
+Bayonet Training Manual                                     16mo,   0 30
+
+Beadle, C. Chapters on Papermaking. Five Volumes      12mo, each,  *2 00
+
+Beaumont, R. Color in Woven Design                           8vo,  *6 00
+
+---- Finishing of Textile Fabrics                            8vo,  *4 00
+
+---- Standard Cloths                                         8vo,  *5 00
+
+Beaumont, W. W. The Steam-Engine Indicator                   8vo,   2 50
+
+Bechhold, H. Colloids in Biology and Medicine. Trans.
+  by J. G. Bullowa                                         (_In Press._)
+
+Beckwith, A. Pottery                                  8vo, paper,   0 60
+
+Bedell, F., and Pierce, C. A. Direct and Alternating
+  Current Manual                                             8vo,   4 00
+
+Beech, F. Dyeing of Cotton Fabrics                           8vo,   4 00
+
+---- Dyeing of Woolen Fabrics                                8vo,  *3 50
+
+Begtrup, J. The Slide Valve                                  8vo,  *2 00
+
+Beggs, G. E. Stresses in Railway Girders and Bridges       (_In Press._)
+
+Bender, C. E. Continuous Bridges. (Science Series No. 26.)  16mo,   0 50
+
+---- Proportions of Pins used in Bridges. (Science
+  Series No. 4.)                                            16mo,   0 50
+
+Bengough, G. D. Brass. (Metallurgy Series.)                (_In Press._)
+
+Bennett, H. G. The Manufacture of Leather                    8vo,  *5 00
+
+Bernthsen, A. A Text book of Organic Chemistry. Trans.
+  by G. M'Gowan                                             12mo,  *3 00
+
+Bersch. J. Manufacture of Mineral and Lake Pigments.
+  Trans. by A. C. Wright                                     8vo,  *5 00
+
+Bertin, L. E. Marine Boilers. Trans. by L. S. Robertson      8vo,   5 00
+
+Beveridge, J. Papermaker's Pocket Book                      12mo,  *4 00
+
+Binnie, Sir A. Rainfall Reservoirs and Water Supply          8vo,   3 00
+
+Binns, C. F. Manual of Practical Potting                     8vo,  *7 50
+
+---- The Potter's Craft                                     12mo,  *2 00
+
+Birchmore, W. H. Interpretation of Gas Analysis             12mo,  *1 25
+
+Blaine, R. G. The Calculus and Its Applications             12mo,  *1 50
+
+Blake, W. H. Brewers' Vade Mecum                             8vo,  *4 00
+
+Blasdale, W. C. Quantitative Chemical Analysis.
+  (Van Nostrand's Textbooks.)                               12mo,  *2 50
+
+Bligh, W. G. The Practical Design of Irrigation Works        8vo,  *6 00
+
+Bloch, L. Science of Illumination. Trans. by W. C. Clinton   8vo,  *2 50
+
+Blok, A. Illumination and Artificial Lighting               12mo,   1 25
+
+Bluecher, H. Modern Industrial Chemistry. Trans. by
+  J. P. Millington.                                          8vo,  *7 50
+
+Blyth, A. W. Foods: Their Composition and Analysis           8vo,   7 50
+
+---- Poisons: Their Effects and Detection                    8vo,   7 50
+
+Boeckmann, F. Celluloid                                      12mo,  *2 50
+
+Bodmer, G. R. Hydraulic Motors and Turbines                 12mo,   5 00
+
+Boileau, J. T. Traverse Tables                               8vo,   5 00
+
+Bonney, G. E. The Electro-platers' Handbook                 12mo,   1 50
+
+Booth, N. Guide to the Ring-spinning Frame                  12mo,  *1 25
+
+Booth, W. H. Water Softening and Treatment                   8vo,  *2 50
+
+---- Superheaters and Superheating and Their Control         8vo,  *1 50
+
+Bottcher, A. Cranes: Their Construction, Mechanical
+  Equipment and Working. Trans. by A. Tolhausen              4to, *10 00
+
+Bottler, M. Modern Bleaching Agents. Trans. by C. Salter    12mo,  *2 50
+
+Bottone, S. R. Magnetos for Automobilists                   12mo,  *1 00
+
+Boulton, S. B. Preservation of Timber. (Science
+  Series No. 82.).                                          16mo,   0 50
+
+Bourcart, E. Insecticides, Fungicides and Weedkillers        8vo,  *4 50
+
+Bourgougnon, A. Physical Problems. (Science Series
+  No. 113.)                                                 16mo,   0 50
+
+Bourry, E. Treatise on Ceramic Industries. Trans.
+  by A. B. Searle.                                           8vo,  *5 00
+
+Bowie, A. J., Jr. A Practical Treatise on Hydraulic Mining   8vo,   5 00
+
+Bowles, O. Tables of Common Rocks. (Science Series
+  No. 125.).                                                16mo,   0 50
+
+Bowser, E. A. Elementary Treatise on Analytic Geometry      12mo,   1 75
+
+---- Elementary Treatise on the Differential and
+   Integral Calculus.                                       12mo,   2 25
+
+---- Elementary Treatise on Analytic Mechanics              12mo,   3 00
+
+---- Elementary Treatise on Hydro-mechanics                 12mo,   2 50
+
+---- A Treatise on Roofs and Bridges                        12mo,  *2 25
+
+Boycott, G. W. M. Compressed Air Work and Diving             8vo,  *4 00
+
+Bragg, E. M. Marine Engine Design                           12mo,  *2 00
+
+---- Design of Marine Engines and Auxiliaries                8vo,  *3 00
+
+Brainard, F. R. The Sextant. (Science Series No. 101.)      16mo,
+
+Brassey's Naval Annual for 1915. War Edition                 8vo,   4 00
+
+Briggs, R., and Wolff, A. R. Steam-Heating. (Science
+  Series No. 67.)                                           16mo,   0 50
+
+Bright, C. The Life Story of Sir Charles Tilson Bright       8vo,  *4 50
+
+Brislee, T. J. Introduction to the Study of Fuel.
+  (Outlines of Industrial Chemistry.)                        8vo,  *3 00
+
+Broadfoot, S. K. Motors, Secondary Batteries.
+  (Installation Manuals Series.)                            12mo,  *0 75
+
+Broughton, H. H. Electric Cranes and Hoists                        *9 00
+
+Brown, G. Healthy Foundations. (Science Series No. 80.)     16mo,   0 50
+
+Brown, H. Irrigation                                         8vo,  *5 00
+
+Brown, H. Rubber                                             8vo,  *2 00
+
+---- W. A. Portland Cement Industry                          8vo,   3 00
+
+Brown, Wm. N. Dipping, Burnishing, Lacquering and Bronzing
+  Brass Ware                                                12mo,  *1 25
+
+---- Handbook on Japanning                                  12mo,  *1 50
+
+Brown, Wm. N. The Art of Enamelling on Metal                12mo,  *1 00
+
+---- House Decorating and Painting                          12mo,  *1 50
+
+---- History of Decorative Art                              12mo,  *1 25
+
+---- Workshop Wrinkles                                       8vo,  *1 00
+
+Browne, C. L. Fitting and Erecting of Engines                8vo,  *1 50
+
+Browne, R. E. Water Meters. (Science Series No. 81.)        16mo,   0 50
+
+Bruce, E. M. Pure Food Tests                                12mo,  *1 25
+
+Brunner, R. Manufacture of Lubricants, Shoe Polishes
+   and Leather Dressings. Trans. by C. Salt                  8vo,  *3 00
+
+Buel, R. H. Safety Valves. (Science Series No. 21.)         16mo,   0 50
+
+Burley, G. W. Lathes, Their Construction and Operation      12mo,   1 25
+
+Burnside, W. Bridge Foundations                             12mo,  *1 50
+
+Burstall, F. W. Energy Diagram for Gas. With Text            8vo,   1 50
+
+---- Diagram. Sold separately                                      *1 00
+
+Burt, W. A. Key to the Solar Compass               16mo, leather,   2 50
+
+Buskett, E. W. Fire Assaying                                12mo,  *1 25
+
+Butler, H. J. Motor Bodies and Chassis                       8vo,  *2 50
+
+Byers, H. G., and Knight, H. G. Notes on Qualitative
+  Analysis                                                   8vo,  *1 50
+
+
+Cain, W. Brief Course in the Calculus                       12mo,  *1 75
+
+---- Elastic Arches. (Science Series No. 48.)               16mo,   0 50
+
+---- Maximum Stresses. (Science Series No. 38.)             16mo,   0 50
+
+---- Practical Designing Retaining of Walls. (Science
+  Series No. 3.)                                            16mo,   0 50
+
+---- Theory of Steel-concrete Arches and of Vaulted
+  Structures. (Science Series No. 42.)                      16mo,   0 50
+
+---- Theory of Voussoir Arches. (Science Series No. 12.)    16mo,   0 50
+
+---- Symbolic Algebra. (Science Series No. 73.)             16mo,   0 50
+
+Carpenter, F. D. Geographical Surveying. (Science
+  Series No. 37.)                                           16mo,
+
+Carpenter, R. C., and Diederichs, H. Internal Combustion
+  Engines                                                    8vo,  *5 00
+
+Carter, H. A. Ramie (Rhea), China Grass                     12mo,  *2 00
+
+Carter, H. R. Modern Flax, Hemp, and Jute Spinning           8vo,  *3 00
+
+---- Bleaching, Dyeing and Finishing of Fabrics              8vo,  *1 00
+
+Cary, E. R. Solution of Railroad Problems with the
+  Slide Rule                                                16mo,  *1 00
+
+Casler, M. D. Simplified Reinforced Concrete Mathematics    12mo,  *1 00
+
+Cathcart, W. L. Machine Design. Part I. Fastenings           8vo,  *3 00
+
+Cathcart, W. L., and Chaffee, J. I. Elements of
+  Graphic Statics                                            8vo,  *3 00
+
+---- Short Course in Graphics                               12mo,   1 50
+
+Caven, R. M., and Lander, G. D. Systematic Inorganic
+  Chemistry                                                 12mo,  *2 00
+
+Chalkley, A. P. Diesel Engines                               8vo,  *4 00
+
+Chambers' Mathematical Tables                                8vo,   1 75
+
+Chambers, G. F. Astronomy                                   16mo,  *1 50
+
+Chappel, E. Five Figure Mathematical Tables                  8vo,  *2 00
+
+Charnock, Mechanical Technology                              8vo,  *3 00
+
+Charpentier, P. Timber                                       8vo,  *6 00
+
+Chatley, H. Principles and Designs of Aeroplanes.
+  (Science Series No. 126)                                  16mo,   0 50
+
+---- How to Use Water Power                                 12mo,  *1 00
+
+---- Gyrostatic Balancing                                    8vo,  *1 00
+
+Child, C. D. Electric Arc                                    8vo,  *2 00
+
+Christian, M. Disinfection and Disinfectants. Trans.
+  by Chas. Salter                                           12mo,   2 00
+
+Christie, W. W. Boiler-waters, Scale, Corrosion, Foaming     8vo,  *3 00
+
+---- Chimney Design and Theory                               8vo,  *3 00
+
+---- Furnace Draft. (Science Series No. 123.)               16mo,   0 50
+
+---- Water: Its Purification and Use in the Industries       8vo,  *2 00
+
+Church's Laboratory Guide. Rewritten by Edward Kinch         8vo,  *1 50
+
+Clapham, J. H. Woolen and Worsted Industries                 8vo,   2 00
+
+Clapperton, G. Practical Papermaking                         8vo,   2 50
+
+Clark, A. G. Motor Car Engineering.
+    Vol. I. Construction                                           *3 00
+    Vol. II. Design                                          8vo,  *3 00
+
+Clark, C. H. Marine Gas Engines                             12mo,  *1 50
+
+Clark, J. M. New System of Laying Out Railway Turnouts      12mo,   1 00
+
+Clarke, J. W., and Scott, W. Plumbing Practice.
+    Vol. I. Lead Working and Plumbers' Materials             8vo,  *4 00
+    Vol. II. Sanitary Plumbing and Fittings                (_In Press._)
+    Vol. III. Practical Lead Working on Roofs              (_In Press._)
+
+Clarkson, R. B. Elementary Electrical Engineering          (_In Press._)
+
+Clausen-Thue, W. A B C Universal Commercial Telegraphic
+  Code. Sixth Edition                                      (_In Press._)
+
+Clerk, D., and Idell, F. E. Theory of the Gas Engine.
+  (Science Series No. 62.)                                  16mo,   0 50
+
+Clevenger, S. R. Treatise on the Method of
+  Government Surveying.                            16mo, morocco,   2 50
+
+Clouth, F. Rubber, Gutta-Percha, and Balata                  8vo,  *5 00
+
+Cochran, J. Concrete and Reinforced Concrete Specifications  8vo,  *2 50
+
+---- Inspection of Concrete Construction                     8vo,  *4 00
+
+---- Treatise on Cement Specifications                       8vo,  *1 00
+
+Cocking, W. C. Calculations for Steel-Frame Structures      12mo,  *2 25
+
+Coffin, J. H. C. Navigation and Nautical Astronomy          12mo,  *3 50
+
+Colburn, Z., and Thurston, R. H. Steam Boiler
+  Explosions. (Science Series No. 2.)                       16mo,   0 50
+
+Cole, R. S. Treatise on Photographic Optics                 12mo,   1 50
+
+Coles-Finch, W. Water, Its Origin and Use                    8vo,  *5 00
+
+Collins, J. E. Useful Alloys and Memoranda for
+  Goldsmiths, Jewelers.                                     16mo,   0 50
+
+Collis, A. G. High and Low Tension Switch-Gear Design        8vo,  *3 50
+
+---- Switchgear. (Installation Manuals Series.)             12mo,  *0 50
+
+Comstock, D. F., and Troland, L. T. The Nature
+  of Electricity and Matter                                  8vo,  *2 00
+
+Coombs, H. A. Gear Teeth. (Science Series No. 120.)         16mo,   0 50
+
+Cooper, W. R. Primary Batteries                              8vo,  *4 00
+
+Copperthwaite, W. C. Tunnel Shields                          4to,  *9 00
+
+Corfield, W. H. Dwelling Houses. (Science Series No. 50.)   16mo,   0 50
+
+---- Water and Water-Supply. (Science Series No. 17.)       16mo,   0 50
+
+Cornwall, H. B. Manual of Blow-pipe Analysis                 8vo,  *2 50
+
+Cowee, G. A. Practical Safety Methods and Devices            8vo,  *3 00
+
+Cowell, W. B. Pure Air, Ozone, and Water                    12mo,  *2 00
+
+Craig, J. W., and Woodward, W. P. Questions and
+  Answers About Electrical Apparatus               12mo, leather,   1 50
+
+Craig, T. Motion of a Solid in a Fuel. (Science
+  Series No. 49.)                                           16mo,   0 50
+
+---- Wave and Vortex Motion. (Science Series No. 43.)       16mo,   0 50
+
+Cramp, W. Continuous Current Machine Design                  8vo,  *2 50
+
+Crehore, A. C. Mystery of Matter and Energy                  8vo,   1 00
+
+Creedy, F. Single Phase Commutator Motors                    8vo,  *2 00
+
+Crocker, F. B. Electric Lighting. Two Volumes.               8vo,
+    Vol. I. The Generating Plant                                    3 00
+    Vol. II. Distributing Systems and Lamps
+
+Crocker, F. B., and Arendt, M. Electric Motors               8vo,  *2 50
+
+Crocker, F. B., and Wheeler, S. S. The Management
+  of Electrical Machinery                                   12mo,  *1 00
+
+Cross, C. F., Bevan, E. J., and Sindall, R. W. Wood
+  Pulp and Its Applications. (Westminster Series.)           8vo,  *2 00
+
+Crosskey, L. R. Elementary Perspective                       8vo,   1 25
+
+Crosskey, L. R., and Thaw, J. Advanced Perspective           8vo,   1 50
+
+Culley, J. L. Theory of Arches. (Science Series No. 87.)    16mo,   0 50
+
+Cushing, H. C., Jr., and Harrison, N. Central Station
+  Management                                                       *2 00
+
+
+Dadourian, H. M. Analytical Mechanics                       12mo,  *3 00
+
+Dana, R. T. Handbook of Construction plant         12mo, leather,  *5 00
+
+Danby, A. Natural Rock Asphalts and Bitumens                 8vo,  *2 50
+
+Davenport, C. The Book. (Westminster Series.)                8vo,  *2 00
+
+Davey, N. The Gas Turbine                                    8vo,  *4 00
+
+Davies, F. H. Electric Power and Traction                    8vo,  *2 00
+
+---- Foundations and Machinery Fixing. (Installation
+  Manual Series.)                                           16mo,  *1 00
+
+Deerr, N. Sugar Cane                                         8vo,   8 00
+
+Deite, C. Manual of Soapmaking. Trans. by S. T. King         4to,  *5 00
+
+De la Coux, H. The Industrial Uses of Water. Trans.
+  by A. Morris.                                              8vo,  *4 50
+
+Del Mar, W. A. Electric Power Conductors                     8vo,  *2 00
+
+Denny, G. A. Deep-level Mines of the Rand                    4to, *10 00
+
+---- Diamond Drilling for Gold                                     *5 00
+
+De Roos, J. D. C. Linkages. (Science Series No. 47.)        16mo,   0 50
+
+Derr, W. L. Block Signal Operation                   Oblong 12mo,  *1 50
+
+---- Maintenance-of-Way Engineering                  (_In Preparation._)
+
+Desaint, A. Three Hundred Shades and How to Mix Them         8vo,  *8 00
+
+De Varona, A. Sewer Gases. (Science Series No. 55.)         16mo,   0 50
+
+Devey, R. G. Mill and Factory Wiring. (Installation
+  Manuals Series.)                                          12mo,  *1 00
+
+Dibdin, W. J. Purification of Sewage and Water               8vo,   6 50
+
+Dichmann, Carl. Basic Open-Hearth Steel Process             12mo,  *3 50
+
+Dieterich, K. Analysis of Resins, Balsams, and Gum Resins    8vo,  *3 00
+
+Dilworth, E. C. Steel Railway Bridges                        4to,  *4 00
+
+Dinger, Lieut. H. C. Care and Operation of Naval
+  Machinery                                                 12mo,  *2 00
+
+Dixon, D. B. Machinist's and Steam Engineer's
+  Practical Calculator.                            16mo, morocco,   1 25
+
+Dodge, G. F. Diagrams for Designing Reinforced
+  Concrete Structures,                                     folio,  *4 00
+
+Dommett, W. E. Motor Car Mechanism                          12mo,  *1 50
+
+Dorr, B. F. The Surveyor's Guide and Pocket
+  Table-book.                                      16mo, morocco,   2 00
+
+Draper, C. H. Elementary Text-book of Light,
+  Heat and Sound                                            12mo,   1 00
+
+---- Heat and the Principles of Thermo-dynamics             12mo,  *2 00
+
+Dron, R. W. Mining Formulas                                 12mo,   1 00
+
+Dubbel, H. High Power Gas Engines                            8vo,  *5 00
+
+Dumesny, P., and Noyer, J. Wood Products, Distillates,
+  and Extracts.                                              8vo,  *4 50
+
+Duncan, W. G., and Penman, D. The Electrical Equipment
+  of Collieries.                                             8vo,  *4 00
+
+Dunkley, W. G. Design of Machine Elements                    8vo,   1 50
+
+Dunstan, A. E., and Thole, F. B. T. Textbook of
+  Practical Chemistry.                                      12mo,  *1 40
+
+Durham, H. W. Saws                                           8vo,   2 50
+
+Duthie, A. L. Decorative Glass Processes.
+  (Westminster Series.).                                     8vo,  *2 00
+
+Dwight, H. B. Transmission Line Formulas                     8vo,  *2 00
+
+Dyson, S. S. Practical Testing of Raw Materials              8vo,  *5 00
+
+Dyson, S. S., and Clarkson, S. S. Chemical Works             8vo,  *7 50
+
+
+Eccles, W. H. Wireless Telegraphy and Telephony             12mo,  *4 50
+
+Eck, J. Light, Radiation and Illumination. Trans.
+  by Paul Hogner,                                            8vo,  *2 50
+
+Eddy, H. T. Maximum Stresses under Concentrated Loads        8vo,   1 50
+
+Eddy, L. C. Laboratory Manual of Alternating Currents       12mo,   0 50
+
+Edelman, P. Inventions and Patents                          12mo,  *1 50
+
+Edgcumbe, K. Industrial Electrical Measuring
+  Instruments                                         8vo, (_In Press._)
+
+Edler, R. Switches and Switchgear. Trans.
+  by Ph. Laubach                                             8vo,  *4 00
+
+Eissler, M. The Metallurgy of Gold                           8vo,   7 50
+
+---- The Metallurgy of Silver                                8vo,   4 00
+
+---- The Metallurgy of Argentiferous Lead                    8vo,   5 00
+
+---- A Handbook on Modern Explosives                         8vo,   5 00
+
+Ekin, T. C. Water Pipe and Sewage Discharge Diagrams       folio,  *3 00
+
+Electric Light Carbons, Manufacture of                       8vo,   1 00
+
+Eliot, C. W., and Storer, F. H. Compendious Manual
+  of Qualitative Chemical Analysis                          12mo,  *1 25
+
+Ellis, C. Hydrogenation of Oils                       8vo, (_In Press._)
+
+Ellis, G. Modern Technical Drawing                           8vo,  *2 00
+
+Ennis, Wm. D. Linseed Oil and Other Seed Oils                8vo,  *4 00
+
+---- Applied Thermodynamics                                  8vo,  *4 50
+
+---- Flying Machines To-day                                 12mo,  *1 50
+
+---- Vapors for Heat Engines                                12mo,  *1 00
+
+Ermen, W. F. A. Materials Used in Sizing                     8vo,  *2 00
+
+Erwin, M. The Universe and the Atom                         12mo,  *2 00
+
+Evans, C. A. Macadamized Roads                             (_In Press._)
+
+Ewing, A. J. Magnetic Induction in Iron                      8vo,  *4 00
+
+
+Fairie, J. Notes on Lead Ores                               12mo,  *0 50
+
+---- Notes on Pottery Clays                                 12mo,  *1 50
+
+Fairley, W., and Andre, Geo. J. Ventilation of Coal
+  Mines. (Science Series No. 58.)                           16mo,   0 50
+
+Fairweather, W. C. Foreign and Colonial Patent Laws          8vo,  *3 00
+
+Falk, M. S. Cement Mortars and Concretes                     8vo,  *2 50
+
+Fanning, J. T. Hydraulic and Water-supply Engineering        8vo,  *5 00
+
+Fay, I. W. The Coal-tar Colors                               8vo,  *4 00
+
+Fernbach, R. L. Glue and Gelatine                            8vo,  *3 00
+
+Firth, J. B. Practical Physical Chemistry                   12mo,  *1 00
+
+Fischer, E. The Preparation of Organic Compounds.
+  Trans. by R. V. Stanford                                  12mo,  *1 25
+
+Fish, J. C. L. Lettering of Working Drawings          Oblong 8vo,   1 00
+
+---- Mathematics of the Paper Location of a Railroad
+  paper                                                     12mo,  *0 25
+
+Fisher, H. K. C., and Darby, W. C. Submarine Cable
+  Testing                                                    8vo,  *3 50
+
+Fleischmann, W. The Book of the Dairy. Trans. by
+  C. M. Aikman                                               8vo,   4 00
+
+Fleming, J. A. The Alternate-current Transformer. Two
+  Volumes.                                                   8vo.
+    Vol. I. The Induction of Electric Currents                     *5 00
+    Vol. II. The Utilization of Induced Currents                   *5 00
+
+---- Propagation of Electric Currents                        8vo,  *3 00
+
+---- A Handbook for the Electrical Laboratory and
+  Testing Room. Two Volumes                            8vo, each,  *5 00
+
+Fleury, P. Preparation and Uses of White Zinc Paints         8vo,  *2 50
+
+Flynn, P. J. Flow of Water. (Science Series No. 84.)        12mo,   0 50
+
+---- Hydraulic Tables. (Science Series No. 66.)             16mo,   0 50
+
+Forgie, J. Shield Tunneling                           8vo. (_In Press._)
+
+Foster, H. A. Electrical Engineers' Pocket-book.
+  (_Seventh Edition._)                             12mo, leather,   5 00
+
+---- Engineering Valuation of Public Utilities
+  and Factories                                              8vo,  *3 00
+
+---- Handbook of Electrical Cost Data                  8vo (_In Press._)
+
+Fowle, F. F. Overhead Transmission Line Crossings           12mo,  *1 50
+
+---- The Solution of Alternating Current Problems      8vo (_In Press._)
+
+Fox, W. G. Transition Curves. (Science Series No. 110.)     16mo,   0 50
+
+Fox, W., and Thomas, C. W. Practical Course in
+  Mechanical Drawing                                        12mo,   1 25
+
+Foye, J. C. Chemical Problems.
+  (Science Series No. 69.)                                  16mo,   0 50
+
+---- Handbook of Mineralogy. (Science Series No. 86.)       16mo,   0 50
+
+Francis, J. B. Lowell Hydraulic Experiments                  4to,  15 00
+
+Franzen, H. Exercises in Gas Analysis                       12mo,  *1 00
+
+Freudemacher, P. W. Electrical Mining Installations.
+  (Installation Manuals Series.)                            12mo,  *1 00
+
+Frith, J. Alternating Current Design                         8vo,  *2 00
+
+Fritsch, J. Manufacture of Chemical Manures. Trans.
+  by D. Grant.                                               8vo,  *4 00
+
+Frye, A. I. Civil Engineers' Pocket-book           12mo, leather,  *5 00
+
+Fuller, G. W. Investigations into the Purification of
+  the Ohio River                                             4to, *10 00
+
+Furnell, J. Paints, Colors, Oils, and Varnishes              8vo,  *1 00
+
+
+Gairdner, J. W. I. Earthwork                           8vo (_In Press._)
+
+Gant, L. W. Elements of Electric Traction                    8vo,  *2 50
+
+Garcia, A. J. R. V. Spanish-English Railway Terms            8vo,  *4 50
+
+Gardner, H. A. Paint Researches, and Their Practical
+  Applications                                               8vo,  *5 00
+
+Garforth, W. E. Rules for Recovering Coal Mines
+  after Explosions and Fires                       12mo, leather,   1 50
+
+Garrard, C. C. Electric Switch and Controlling Gear          8vo,  *6 00
+
+Gaudard, J. Foundations. (Science Series No. 34.)           16mo,   0 50
+
+Gear, H. B., and Williams, P. F. Electric Central
+  Station Distribution Systems                               8vo,  *3 50
+
+Geerligs, H. C. P. Cane Sugar and Its Manufacture            8vo,  *5 00
+
+Geikie, J. Structural and Field Geology                      8vo,  *4 00
+
+---- Mountains. Their Growth, Origin and Decay               8vo,  *4 00
+
+---- The Antiquity of Man in Europe                          8vo,  *3 00
+
+Georgi, F., and Schubert, A. Sheet Metal Working.
+  Trans. by C. Salter                                        8vo,   3 00
+
+Gerhard, W. P. Sanitation, Watersupply and Sewage
+  Disposal of Country Houses                                12mo,  *2 00
+
+---- Gas Lighting  (Science Series No. 111.)                16mo,   0 50
+
+---- Household Wastes. (Science Series No. 97.)             16mo,   0 50
+
+---- House Drainage. (Science Series No. 63.)               16mo,   0 50
+
+---- Sanitary Drainage of Buildings. (Science Series
+  No. 93.)                                                  16mo,   0 50
+
+Gerhardi, C. W. H. Electricity Meters                        8vo,  *4 00
+
+Geschwind, L. Manufacture of Alum and Sulphates.
+  Trans. by C. Salter                                        8vo,  *5 00
+
+Gibbings, A. H. Oil Fuel Equipment for Locomotives           8vo,  *5 00
+
+Gibbs, W. E. Lighting by Acetylene                          12mo,  *1 50
+
+Gibson, A. H. Hydraulics and Its Application                 8vo,  *5 00
+
+---- Water Hammer in Hydraulic Pipe Lines                   12mo,  *2 00
+
+Gibson, A. H., and Ritchie, E. G. Circular
+  Arc Bow Girder                                             4to,  *3 50
+
+Gilbreth, F. B. Motion Study                                12mo,  *2 00
+
+---- Bricklaying System                                      8vo,  *3 00
+
+---- Field System                                  12mo, leather,  *3 00
+
+---- Primer of Scientific Management                        12mo,  *1 00
+
+Gillette, H. P. Handbook of Cost Data              12mo, leather,  *5 00
+
+---- Rock Excavation Methods and Cost                       12mo,  *5 00
+
+---- and Dana, R. T. Cost Keeping and Management
+  Engineering                                                8vo,  *3 50
+
+---- and Hill, C. S. Concrete Construction, Methods
+  and Cost                                                   8vo,  *5 00
+
+Gillmore, Gen. Q. A. Roads, Streets, and Pavements          12mo,   1 25
+
+Godfrey, E. Tables for Structural Engineers        16mo, leather,  *2 50
+
+Golding, H. A. The Theta-Phi Diagram                        12mo,  *1 25
+
+Goldschmidt, R. Alternating Current Commutator Motor         8vo,  *3 00
+
+Goodchild, W. Precious Stones. (Westminster Series.)         8vo,  *2 00
+
+Goodeve, T. M. Textbook on the Steam-engine                 12mo,   2 00
+
+Gore, G. Electrolytic Separation of Metals                   8vo,  *3 50
+
+Gould, E. S. Arithmetic of the Steam-engine                 12mo,   1 00
+
+---- Calculus. (Science Series No. 112.)                    16mo,   0 50
+
+---- High Masonry Dams. (Science Series No. 22.)            16mo,   0 50
+
+Gould, E. S. Practical Hydrostatics and Hydrostatic
+  Formulas. (Science Series No. 117.)                       16mo,   0 50
+
+Gratacap, L. P. A Popular Guide to Minerals                  8vo,  *3 00
+
+Gray, J. Electrical Influence Machines                      12mo,   2 00
+
+---- Marine Boiler Design                                   12mo,  *1 25
+
+Greenhill, G. Dynamics of Mechanical Flight                  8vo,  *2 50
+
+Gregorius, R. Mineral Waxes. Trans. by C. Salter            12mo,  *3 00
+
+Grierson, R. Some Modern Methods of Ventilation              8vo,  *3 00
+
+Griffiths, A. B. A Treatise on Manures                      12mo,   3 00
+
+---- Dental Metallurgy                                       8vo,  *3 50
+
+Gross, E. Hops                                               8vo,  *4 50
+
+Grossman, J. Ammonia and Its Compounds                      12mo,  *1 25
+
+Groth, L. A. Welding and Cutting Metals by Gases or
+  Electricity. (Westminster Series)                          8vo,  *2 00
+
+Grover, F. Modern Gas and Oil Engines                        8vo,  *2 00
+
+Gruner, A. Power-loom Weaving                                8vo,  *3 00
+
+Gueldner, Hugo. Internal Combustion Engines. Trans.
+  by H. Diederichs                                           4to, *15 00
+
+Gunther, C. O. Integration                                   8vo,  *1 25
+
+Gurden, R. L. Traverse Tables                folio, half morocco,  *7 50
+
+Guy, A. E. Experiments on the Flexure of Beams               8vo,  *1 25
+
+
+Haenig, A. Emery and Emery Industry                          8vo,  *2 50
+
+Hainbach, R. Pottery Decoration. Trans. by C. Salter        12mo,  *3 00
+
+Hale, W. J. Calculations of General Chemistry               12mo,  *1 00
+
+Hall, C. H. Chemistry of Paints and Paint Vehicles          12mo,  *2 00
+
+Hall, G. L. Elementary Theory of Alternate Current
+  Working                                                    8vo,  *1 50
+
+Hall, R. H. Governors and Governing Mechanism               12mo,  *2 00
+
+Hall, W. S. Elements of the Differential and Integral
+  Calculus                                                   8vo,  *2 25
+
+---- Descriptive Geometry             8vo volume and a 4to atlas,  *3 50
+
+Haller, G. F., and Cunningham, E. T. The Tesla Coil         12mo,  *1 25
+
+Halsey, F. A. Slide Valve Gears                             12mo,   1 50
+
+---- The Use of the Slide Rule. (Science Series No.
+  114.)                                                     16mo,   0 50
+
+---- Worm and Spiral Gearing. (Science Series No.
+  116.)                                                     16mo,   0 50
+
+Hancock, H. Textbook of Mechanics and Hydrostatics           8vo,   1 50
+
+Hancock, W. C. Refractory Materials. (Metallurgy
+  Series.)                                                 (_In Press._)
+
+Hardy, E. Elementary Principles of Graphic Statics          12mo,  *1 50
+
+Haring, H. Engineering Law
+    Vol. I. Law of Contract                                  8vo,  *4 00
+
+Harper, J. H. Hydraulic Tables on the Flow of Water         16mo,  *2 00
+
+Harris, S. M. Practical Topographical Surveying            (_In Press._)
+
+Harrison, W. B. The Mechanics' Tool-book                    12mo,   1 50
+
+Hart, J. W. External Plumbing Work                           8vo,  *3 00
+
+---- Hints to Plumbers on Joint Wiping                       8vo,  *3 00
+
+---- Principles of Hot Water Supply                          8vo,  *3 00
+
+---- Sanitary Plumbing and Drainage                          8vo,  *3 00
+
+Haskins, C. H. The Galvanometer and Its Uses                16mo,   1 50
+
+Hatt, J. A. H. The Colorist                          square 12mo,  *1 50
+
+Hausbrand, E. Drying by Means of Air and Steam.
+  Trans. by A. C. Wright                                    12mo,  *2 00
+
+---- Evaporating, Condensing and Cooling Apparatus.
+  Trans. by A. C. Wright                                     8vo,  *5 00
+
+Hausmann, E. Telegraph Engineering                           8vo,  *3 00
+
+Hausner, A. Manufacture of Preserved Foods and
+  Sweetmeats. Trans. by A. Morris and H. Robson              8vo,  *3 00
+
+Hawkesworth, J. Graphical Handbook for Reinforced
+  Concrete Design.                                           4to,  *2 50
+
+Hay, A. Continuous Current Engineering                       8vo,  *2 50
+
+Hayes, H. V. Public Utilities, Their Cost New and
+  Depreciation                                               8vo,  *2 00
+
+---- Public Utilities, Their Fair Present Value and
+  Return                                                     8vo,  *2 00
+
+Heath, F. H. Chemistry of Photography 8vo.                 (_In Press._)
+
+Heather, H. J. S. Electrical Engineering                     8vo,  *3 50
+
+Heaviside, O. Electromagnetic Theory. Vols. I and II   8vo, each,  *5 00
+                                     Vol. III                8vo,  *7 50
+
+Heck, R. C. H. The Steam Engine and Turbine                  8vo,  *3 50
+
+---- Steam-Engine and Other Steam Motors. Two Volumes.
+    Vol. I. Thermodynamics and the Mechanics                 8vo,  *3 50
+    Vol. II. Form, Construction, and Working                 8vo,  *5 00
+
+---- Notes on Elementary Kinematics                  8vo, boards,  *1 00
+
+---- Graphics of Machine Forces                      8vo, boards,  *1 00
+
+Heermann, P. Dyers' Materials. Trans. by A. C.
+  Wright                                                    12mo,  *2 50
+
+Heidenreich, E. L. Engineers' Pocketbook of Reinforced
+  Concrete                                         16mo, leather,  *3 00
+
+Hellot, Macquer and D'Apligny. Art of Dyeing Wool, Silk
+  and Cotton                                                 8vo,  *2 00
+
+Henrici, O. Skeleton Structures                              8vo,   1 50
+
+Hering, C., and Getman, F. H. Standard Tables of
+  Electro-Chemical Equivalents                              12mo,  *1 50
+
+Hering, D. W. Essentials of Physics for College
+  Students                                                   8vo,  *1 75
+
+Hering-Shaw, A. Domestic Sanitation and Plumbing.
+  Two Vols.                                                  8vo,  *5 00
+
+Hering-Shaw, A. Elementary Science                           8vo,  *2 00
+
+Herington, C. F. Powdered Coal and Fuel                    (_In Press._)
+
+Herrmann, G. The Graphical Statics of Mechanism.
+  Trans. by A. P. Smith                                     12mo,   2 00
+
+Herzfeld, J. Testing of Yarns and Textile Fabrics            8vo,  *3 50
+
+Hildebrandt, A. Airships, Past and Present                   8vo,  *3 50
+
+Hildenbrand, B. W. Cable-Making. (Science Series No. 32.)   16mo,   0 50
+
+Hilditch, T. P. A Concise History of Chemistry              12mo,  *1 25
+
+Hill, C. S. Concrete Inspection                             16mo,  *1 00
+
+Hill, J. W. The Purification of Public Water Supplies.
+  New Edition                                              (_In Press._)
+
+---- Interpretation of Water Analysis                      (_In Press._)
+
+Hill, M. J. M. The Theory of Proportion                      8vo,  *2 50
+
+Hiroi, I. Plate Girder Construction. (Science Series
+  No. 95.)                                                  16mo,   0 50
+
+---- Statically-Indeterminate Stresses                      12mo,  *2 00
+
+Hirshfeld, C. F. Engineering Thermodynamics. (Science
+  Series No. 45.)                                           16mo,   0 50
+
+Hoar, A. The Submarine Torpedo Boat                         12mo,  *2 00
+
+Hobart, H. M. Heavy Electrical Engineering                   8vo,  *4 50
+
+---- Design of Static Transformers                          12mo,  *2 00
+
+---- Electricity                                             8vo,  *2 00
+
+---- Electric Trains                                         8vo,  *2 50
+
+---- Electric Propulsion of Ships                            8vo,  *2 50
+
+Hobart, J. F. Hard Soldering, Soft Soldering and Brazing.   12mo,  *1 00
+
+Hobbs, W. R. P. The Arithmetic of Electrical Measurements.  12mo,   0 50
+
+Hoff, J. N. Paint and Varnish Facts and Formulas.           12mo,  *1 50
+
+Hole, W. The Distribution of Gas.                            8vo,  *7 50
+
+Holley, A. L. Railway Practice.                            folio,   6 00
+
+Hopkins, N. M. Model Engines and Small Boats.               12mo,   1 25
+
+Hopkinson, J., Shoolbred, J. N., and Day, R. E.
+  Dynamic Electricity. (Science Series No. 71.)             16mo,   0 50
+
+Horner, J. Practical Ironfounding.                           8vo,  *2 00
+
+---- Gear Cutting, in Theory and Practice.                   8vo,  *3 00
+
+Houghton, C. E. The Elements of Mechanics of Materials.     12mo,  *2 00
+
+Houstoun, R. A. Studies in Light Production.                12mo,   2 00
+
+Hovenden, F. Practical Mathematics for Young Engineers.     12mo,  *1 50
+
+Howe, G. Mathematics for the Practical Man.                 12mo,  *1 25
+
+Howorth, J. Repairing and Riveting Glass, China
+  and Earthenware.                                    8vo, paper,  *0 50
+
+Hoyt, W. E. Chemistry by Experimentation.                    8vo,  *0 70
+
+Hubbard, E. The Utilization of Wood-waste.                   8vo,  *2 00
+
+Huebner, J. Bleaching and Dyeing of Vegetable and
+  Fibrous Materials. (Outlines of Industrial Chemistry.)     8vo,  *5 00
+
+Hudson, O. F. Iron and Steel. (Outlines of Industrial
+  Chemistry.)                                                8vo,  *2 00
+
+Humphrey, J. C. W. Metallography of Strain. (Metallurgy
+  Series.)                                                 (_In Press._)
+
+Humphreys, A. C. The Business Features of Engineering
+  Practice.                                                  8vo,  *1 25
+
+Hunter, A. Bridge Work. 8vo.                               (_In Press._)
+
+Hurst. G. H. Handbook of the Theory of Color.                8vo,  *2 50
+
+---- Dictionary of Chemicals and Raw Products.               8vo,  *4 50
+
+---- Lubricating Oils, Fats and Greases.                     8vo,  *4 00
+
+---- Soaps.                                                  8vo,  *5 00
+
+Hurst, G. H., and Simmons, W. H. Textile Soaps and Oils.     8vo,   3 00
+
+Hurst, H. E., and Lattey, R. T. Text-book of Physics.        8vo,  *3 00
+
+---- Also published in three parts.
+    Part   I. Dynamics and Heat.                                   *1 25
+    Part  II. Sound and Light.                                     *1 25
+    Part III. Magnetism and Electricity.                           *1 50
+
+Hutchinson, R. W., Jr. Long Distance Electric Power
+  Transmission.                                             12mo,  *3 00
+
+Hutchinson, R. W., Jr., and Thomas, W. A. Electricity
+  in Mining.                                         12mo, (_In Press._)
+
+Hutchinson, W. B. Patents and How to Make Money Out
+  of Them.                                                  12mo,   1 00
+
+Hutton, W. S. The Works' Manager's Handbook.                 8vo,   6 00
+
+Hyde, E. W. Skew Arches. (Science Series No. 15.)           16mo,   0 50
+
+Hyde, F. S. Solvents, Oils, Gums, Waxes.                     8vo,  *2 00
+
+
+Induction Coils. (Science Series No. 53.)                   16mo,   0 50
+
+Ingham, A. E. Gearing. A practical treatise.                 8vo,  *2 50
+
+Ingle, H. Manual of Agricultural Chemistry.                  8vo,  *3 00
+
+Inness, C. H. Problems in Machine Design.                   12mo,  *2 00
+
+---- Air Compressors and Blowing Engines.                   12mo,  *2 00
+
+---- Centrifugal Pumps.                                     12mo,  *2 00
+
+---- The Fan.                                               12mo,  *2 00
+
+
+Jacob, A., and Gould, E. S. On the Designing and
+  Construction of Storage Reservoirs. (Science Series
+  No. 6)                                                    16mo,   0 50
+
+Jannettaz, E. Guide to the Determination of
+  Rocks. Trans. by G. W. Plympton.                          12mo,   1 50
+
+Jehl, F. Manufacture of Carbons.                             8vo,  *4 00
+
+Jennings, A. S. Commercial Paints and Paintings.
+  (Westminster Series.)                                      8vo,  *2 00
+
+Jennison, F. H. The Manufacture of Lake Pigments.            8vo,  *3 00
+
+Jepson, G. Cams and the Principles of their Construction.    8vo,  *1 50
+
+---- Mechanical Drawing.                        8vo. (_In Preparation._)
+
+Jervis-Smith, F. J. Dynamometers.                            8vo,  *3 50
+
+Jockin, W. Arithmetic of the Gold and Silversmith.          12mo,  *1 00
+
+Johnson, J. H. Arc Lamps and Accessory Apparatus.
+  (Installation Manuals Series.)                            12mo,  *0 75
+
+Johnson, T. M. Ship Wiring and Fitting. (Installation
+  Manuals Series.)                                          12mo,  *0 75
+
+Johnson, W. McA. The Metallurgy of Nickel.           (_In Preparation._)
+
+Johnston, J. F. W., and Cameron, C. Elements of
+  Agricultural Chemistry and Geology.                       12mo,   2 60
+
+Joly, J. Radioactivity and Geology.                         12mo,  *3 00
+
+Jones, H. C. Electrical Nature of Matter
+  and Radioactivity.                                        12mo,  *2 00
+
+---- Nature of Solution.                                     8vo,  *3 50
+
+---- New Era in Chemistry.                                  12mo,  *2 00
+
+Jones, J. H. Tinplate Industry.                              8vo,  *3 00
+
+Jones, M. W. Testing Raw Materials Used in Paint.           12mo,  *2 00
+
+Jordan, L. C. Practical Railway Spiral.            12mo, leather,  *1 50
+
+Joynson, F. H. Designing and Construction of
+  Machine Gearing.                                           8vo,   2 00
+
+Jueptner, H. F. V. Siderology: The Science of Iron.           8vo,  *5 00
+
+
+Kapp, G. Alternate Current Machinery. (Science
+  Series No. 96.)                                           16mo,   0 50
+
+Kapper, F. Overhead Transmission Lines.                      4to,  *4 00
+
+Keim, A. W. Prevention of Dampness in Buildings.             8vo,  *2 00
+
+Keller, S. S. Mathematics for Engineering Students.  12mo, half leather.
+
+---- and Knox, W. E. Analytical Geometry and Calculus.             *2 00
+
+Kelsey, W. R. Continuous-current Dynamos and Motors.         8vo,  *2 50
+
+Kemble, W. T., and Underhill, C. R. The Periodic Law
+  and the Hydrogen Spectrum.                          8vo, paper,  *0 50
+
+Kennedy, A. B. W., and Thurston, R. H. Kinematics of
+  Machinery. (Science Series No. 54.)                       16mo,   0 50
+
+Kennedy, A. B. W., Unwin, W. C., and Idell,
+  F. E. Compressed Air. (Science Series No. 106.)           16mo,   0 50
+
+Kennedy, R. Electrical Installations. Five Volumes.          4to,  15 00
+    Single Volumes.                                         each,   3 50
+
+---- Flying Machines; Practice and Design.                  12mo,  *2 00
+
+---- Principles of Aeroplane Construction.                   8vo,  *1 50
+
+Kennelly, A. E. Electro-dynamic Machinery.                   8vo,   1 50
+
+Kent, W. Strength of Materials. (Science Series No. 41.)    16mo,   0 50
+
+Kershaw, J. B. C. Fuel, Water and Gas Analysis.              8vo,  *2 50
+
+---- Electrometallurgy. (Westminster Series.)                8vo,  *2 00
+
+---- The Electric Furnace in Iron and Steel Production.     12mo,  *1 50
+
+---- Electro-Thermal Methods of Iron and Steel Production.   8vo,  *3 00
+
+Kindelan, J. Trackman's Helper.                             12mo,   2 00
+
+Kinzbrunner, C. Alternate Current Windings.                  8vo,  *1 50
+
+---- Continuous Current Armatures.                           8vo,  *1 50
+
+---- Testing of Alternating Current Machines.                8vo,  *2 00
+
+Kirkaldy, A. W., and Evans, A. D. History and
+  Economics of Transport.                                    8vo,  *3 00
+
+Kirkaldy, W. G. David Kirkaldy's System of
+  Mechanical Testing.                                        4to,  10 00
+
+Kirkbride, J. Engraving for Illustration.                    8vo,  *1 50
+
+Kirkham, J. E. Structural Engineering.                       8vo,  *5 00
+
+Kirkwood, J. P. Filtration of River Waters.                  4to,   7 50
+
+Kirschke, A. Gas and Oil Engines.                           12mo,  *1 25
+
+Klein, J. F. Design of a High-speed Steam-engine.            8vo,  *5 00
+
+---- Physical Significance of Entropy.                       8vo,  *1 50
+
+Klingenberg, G. Large Electric Power Stations.               4to,  *5 00
+
+Knight, R.-Adm. A. M. Modern Seamanship.                     8vo,  *6 50
+
+Knott, C. G., and Mackay, J. S. Practical Mathematics.       8vo,   2 00
+
+Knox, G. D. Spirit of the Soil.                             12mo,  *1 25
+
+Knox, J. Physico-Chemical Calculations.                     12mo,  *1 25
+
+---- Fixation of Atmospheric Nitrogen. (Chemical
+  Monographs.)                                              12mo,  *0 75
+
+Koester, F. Steam-Electric Power Plants.                     4to,  *5 00
+
+---- Hydroelectric Developments and Engineering.             4to,  *5 00
+
+Koller, T. The Utilization of Waste Products.                8vo,  *3 00
+
+---- Cosmetics.                                              8vo,  *2 50
+
+Koppe, S. W. Glycerine.                                     12mo,  *2 50
+
+Kozmin, P. A. Flour Milling. Trans. by M. Falkner.    8vo. (_In Press._)
+
+Kremann, R. Application of the Physico-Chemical
+  Theory to Technical Processes and Manufacturing Methods.
+  Trans. by H. E. Potts.                                     8vo,  *3 00
+
+Kretchmar, K. Yarn and Warp Sizing.                          8vo,  *4 00
+
+
+Lallier, E. V. Elementary Manual of the Steam Engine.       12mo,  *2 00
+
+Lambert, T. Lead and Its Compounds.                          8vo,  *3 50
+
+---- Bone Products and Manures.                              8vo,  *3 00
+
+Lamborn, L. L. Cottonseed Products.                          8vo,  *3 00
+
+---- Modern Soaps, Candles, and Glycerin.                    8vo,  *7 50
+
+Lamprecht, R. Recovery Work After Pit Fires. Trans.
+  by C. Salter.                                              8vo,  *4 00
+
+Lancaster, M. Electric Cooking, Heating and Cleaning.        8vo,  *1 00
+
+Lanchester, F. W. Aerial Flight. Two Volumes.                8vo.
+    Vol. I. Aerodynamics.                                          *6 00
+    Vol. II. Aerodonetics.                                         *6 00
+
+Lanchester, F. W. The Flying Machine.                        8vo,  *3 00
+
+Lange, K. R. By-Products of Coal-Gas Manufacture.           12mo,   2 00
+
+Larner, E. T. Principles of Alternating Currents.           12mo,  *1 25
+
+La Rue, B. F. Swing Bridges. (Science Series No. 107.)      16mo,   0 50
+
+Lassar-Cohn. Dr. Modern Scientific Chemistry. Trans.
+  by M. M. Pattison Muir                                    12mo,  *2 00
+
+Latimer, L. H., Field, C. J., and Howell, J. W.
+  Incandescent Electric Lighting. (Science
+  Series No. 57.)                                           16mo,   0 50
+
+Latta, M. N. Handbook of American Gas-Engineering Practice.  8vo,  *4 50
+
+---- American Producer Gas Practice.                         4to,  *6 00
+
+Laws, B. C. Stability and Equilibrium of Floating Bodies.    8vo,  *3 50
+
+Lawson, W. R. British Railways. A Financial and
+  Commercial Survey.                                         8vo,   2 00
+
+Leask, A. R. Breakdowns at Sea.                             12mo,   2 00
+
+---- Refrigerating Machinery.                               12mo,   2 00
+
+Lecky, S. T. S. "Wrinkles" in Practical Navigation.          8vo,  10 00
+
+Le Doux, M. Ice-Making Machines. (Science Series No. 46.)   16mo,   0 50
+
+Leeds, C. C. Mechanical Drawing for Trade Schools. oblong    4to,  *2 00
+
+---- Mechanical Drawing for High and Vocational Schools.     4to,  *1 25
+
+Lefevre, L. Architectural Pottery. Trans. by H. K.
+  Bird and W. M. Binns.                                      4to,  *7 50
+
+Lehner, S. Ink Manufacture. Trans. by A. Morris
+  and H. Robson.                                             8vo,  *2 50
+
+Lemstrom, S. Electricity in Agriculture and Horticulture.    8vo,  *1 50
+
+Letts, E. A. Fundamental Problems in Chemistry.              8vo,  *2 00
+
+Le Van, W. B. Steam-Engine Indicator. (Science
+  Series No. 78.)                                           16mo,   0 50
+
+Lewes, V. B. Liquid and Gaseous Fuels. (Westminster
+  Series.)                                                   8vo,  *2 00
+
+---- Carbonization of Coal.                                  8vo,  *3 00
+
+Lewis, L. P. Railway Signal Engineering.                     8vo,  *3 50
+
+Lewis Automatic Machine Rifle; Operation of.                16mo,  *0 75
+
+Licks, H. E. Recreations in Mathematics.                    12mo,  *1 25
+
+Lieber, B. F. Lieber's Five Letter Standard
+  Telegraphic Code.                                          8vo, *10 00
+
+---- Code. German Edition.                                   8vo, *10 00
+
+---- ---- Spanish Edition.                                   8vo, *10 00
+
+---- ---- French Edition.                                    8vo, *10 00
+
+---- Terminal Index.                                         8vo,  *2 50
+
+---- Lieber's Appendix.                                    folio, *15 00
+
+---- ---- Handy Tables.                                      4to,  *2 50
+
+---- Bankers and Stockbrokers' Code and Merchants
+  and Shippers' Blank Tables.                                8vo, *15 00
+
+---- 100,000,000 Combination Code.                           8vo, *10 00
+
+---- Engineering Code.                                       8vo, *12 50
+
+Livermore, V. P., and Williams, J. How to Become
+  a Competent Motorman                                      12mo,  *1 00
+
+Livingstone, R. Design and Construction of Commutators.      8vo,  *2 25
+
+---- Mechanical Design and Construction of Generators.       8vo,  *3 50
+
+Lloyd, S. L. Fertilizer Materials.                         (_In Press._)
+
+Lobben, P. Machinists' and Draftsmen's Handbook.             8vo,   2 50
+
+Lockwood, T. D. Electricity, Magnetism, and
+  Electro-telegraph.                                         8vo,   2 50
+
+---- Electrical Measurement and the Galvanometer.           12mo,   0 75
+
+Lodge, O. J. Elementary Mechanics.                          12mo,   1 50
+
+---- Signalling Across Space without Wires.                  8vo,  *2 00
+
+Loewenstein, L. C., and Crissey, C. P. Centrifugal Pumps.          *4 50
+
+Lomax, J. W. Cotton Spinning.                               12mo,   1 50
+
+Lord, R. T. Decorative and Fancy Fabrics.                    8vo,  *3 50
+
+Loring, A. E. A Handbook of the Electromagnetic Telegraph.  16mo,   0 50
+
+---- Handbook. (Science Series No. 39.)                     16mo,   0 50
+
+Lovell, D. H. Practical Switchwork.                         12mo,  *1 00
+
+Low, D. A. Applied Mechanics (Elementary).                  16mo,   0 80
+
+Lubschez, B. J. Perspective.                                12mo,  *1 50
+
+Lucke, C. E. Gas Engine Design.                              8vo,  *3 00
+
+---- Power Plants: Design, Efficiency, and Power
+  Costs. 2 vols.                                     (_In Preparation._)
+
+Luckiesh, M. Color and Its Application.                      8vo,  *3 00
+
+---- Light and Shade and Their Applications.                 8vo,  *2 50
+
+Lunge, G. Coal-tar and Ammonia. Three Volumes.               8vo, *20 00
+
+---- Technical Gas Analysis.                                 8vo,  *4 00
+
+---- Manufacture of Sulphuric Acid and Alkali. Four Volumes. 8vo,
+     Vol. I. Sulphuric Acid. In three parts.                       18 00
+---- Vol. I. Supplement.                                     8vo,   5 00
+     Vol. II. Salt Cake, Hydrochloric Acid and Leblanc
+       Soda. In two parts.                                        *15 00
+     Vol. III. Ammonia Soda.                                      *10 00
+     Vol. IV. Electrolytic Methods.                        (_In Press._)
+
+---- Technical Chemists' Handbook.                 12mo, leather,  *3 50
+
+---- Technical Methods of Chemical Analysis. Trans.
+       by C. A. Keane in collaboration with
+       the corps of specialists.
+     Vol. I. In two parts.                                   8vo, *15 00
+     Vol. II. In two parts.                                  8vo, *18 00
+     Vol. III. In two parts.                                 8vo, *18 00
+     The set (3 vols.) complete.                                  *50 00
+
+Luquer, L. M. Minerals in Rock Sections.                     8vo,  *1 50
+
+
+Macewen, H. A. Food Inspection.                              8vo,  *2 50
+
+Mackenzie, N. F. Notes on Irrigation Works.                  8vo,  *2 50
+
+Mackie, J. How to Make a Woolen Mill Pay.                    8vo,  *2 00
+
+Maguire, Wm. R. Domestic Sanitary Drainage and Plumbing.     8vo,   4 00
+
+Malcolm, C. W. Textbook on Graphic Statics.                  8vo,  *3 00
+
+Malcolm, H. W. Submarine Telegraph Cable.                  (_In Press._)
+
+Mallet, A. Compound Engines. Trans. by R. R. Buel.
+  (Science Series No. 10.)                                  16mo,
+
+Mansfield, A. N. Electro-magnets. (Science Series No. 64.)  16mo,   0 50
+
+Marks, E. C. R. Construction of Cranes and Lifting
+  Machinery.                                                12mo,  *1 50
+
+---- Construction and Working of Pumps.                     12mo,  *1 50
+
+---- Manufacture of Iron and Steel Tubes.                   12mo,  *2 00
+
+---- Mechanical Engineering Materials.                      12mo,  *1 00
+
+Marks, G. C. Hydraulic Power Engineering.                    8vo,   3 50
+
+---- Inventions, Patents and Designs.                       12mo,  *1 00
+
+Marlow, T. G. Drying Machinery and Practice.                 8vo,  *5 00
+
+Marsh, C. F. Concise Treatise on Reinforced Concrete.        8vo,  *2 50
+
+---- Reinforced Concrete Compression Member Diagram.
+  Mounted on Cloth Boards.                                         *1 50
+
+Marsh, C. F., and Dunn, W. Manual of Reinforced
+  Concrete and Concrete Block Construction.        16mo, morocco,  *2 50
+
+Marshall, W. J., and Sankey, H. R. Gas Engines.
+  (Westminster Series.)                                      8vo,  *2 00
+
+Martin, G. Triumphs and Wonders of Modern Chemistry.         8vo,  *2 00
+
+---- Modern Chemistry and Its Wonders.                       8vo,  *2 00
+
+Martin, N. Properties and Design of Reinforced Concrete.    12mo,  *2 50
+
+Martin, W. D. Hints to Engineers.                           12mo,  *1 50
+
+Massie, W. W., and Underhill, C. R. Wireless Telegraphy
+  and Telephony.                                            12mo,  *1 00
+
+Mathot, R. E. Internal Combustion Engines.                   8vo,  *4 00
+
+Maurice, W. Electric Blasting Apparatus and Explosives.      8vo,  *3 50
+
+---- Shot Firer's Guide.                                     8vo,  *1 50
+
+Maxwell, J. C. Matter and Motion. (Science Series No. 36.)  16mo,   0 50
+
+Maxwell, W. H., and Brown, J. T. Encyclopedia of
+  Municipal and Sanitary Engineering.                        4to, *10 00
+
+Mayer, A. M. Lecture Notes on Physics.                       8vo,   2 00
+
+Mayer, C., and Slippy, J. C. Telephone Line Construction.    8vo,  *3 00
+
+McCullough, E. Practical Surveying.                         12mo,  *2 00
+
+---- Engineering Work in Cities and Towns.                   8vo,  *3 00
+
+---- Reinforced Concrete.                                   12mo,  *1 50
+
+McCullough, R. S. Mechanical Theory of Heat.                 8vo,   3 50
+
+McGibbon, W. C. Indicator Diagrams for Marine Engineers.     8vo,  *3 00
+
+---- Marine Engineers' Drawing Book.                  oblong 4to,  *2 50
+
+McIntosh, J. G. Technology of Sugar.                         8vo,  *5 00
+
+---- Industrial Alcohol.                                     8vo,  *3 00
+
+---- Manufacture of Varnishes and Kindred Industries.
+      Three Volumes.                                         8vo.
+    Vol. I. Oil Crushing, Refining and Boiling.                    *3 50
+    Vol. II. Varnish Materials and Oil Varnish Making.             *4 00
+    Vol. III. Spirit Varnishes and Materials.                      *4 50
+
+McKnight, J. D., and Brown, A. W. Marine Multitubular Boilers.     *1 50
+
+McMaster, J. B. Bridge and Tunnel Centres. (Science
+  Series No. 20.)                                           16mo,   0 50
+
+McMechen, F. L. Tests for Ores, Minerals and Metals.        12mo,  *1 00
+
+McPherson, J. A. Water-works Distribution.                   8vo,   2 50
+
+Meade, A. Modern Gas Works Practice.                         8vo,  *7 50
+
+McGibbon, W. C. Marine Engineers Pocketbook.                12mo,  *4 00
+
+Meade, R. K. Design and Equipment of Small Chemical
+  Laboratories,                                              8vo,
+
+Melick, C. W. Dairy Laboratory Guide.                       12mo,  *1 25
+
+Mensch, L. J. Reinforced Concrete Pocket Book.     16mo, leather,  *4 00
+
+Merck, E. Chemical Reagents; Their Purity and Tests. Trans.
+  by H. E. Schenck.                                          8vo,   1 00
+
+Merivale, J. H. Notes and Formulae for Mining Students.     12mo,   1 50
+
+Merritt, Wm. H. Field Testing for Gold and Silver. 16mo, leather,   1 50
+
+Mierzinski, S. Waterproofing of Fabrics. Trans. by A.
+  Morris and H. Robson.                                      8vo,  *2 50
+
+Miessner, B. F. Radio Dynamics.                             12mo,  *2 00
+
+Miller, G. A. Determinants. (Science Series No. 105.)       16mo,
+
+Miller, W. J. Introduction to Historical Geology.           12mo,  *2 00
+
+Milroy, M. E. W. Home Lace-making.                          12mo,  *1 00
+
+Mills, C. N. Elementary Mechanics for Engineers.             8vo,  *1 00
+
+Mitchell, C. A. Mineral and Aerated Waters.                  8vo,  *3 00
+
+Mitchell, C. A., and Prideaux, R. M. Fibres Used in
+  Textile and Allied Industries.                             8vo,  *3 00
+
+Mitchell, C. F., and G. A. Building Construction
+       and Drawing.                                         12mo.
+     Elementary Course.                                            *1 50
+     Advanced Course.                                              *2 50
+
+Monckton, C. C. F. Radiotelegraphy. (Westminster Series.)    8vo,  *2 00
+
+Monteverde, R. D. Vest Pocket Glossary of English-Spanish,
+  Spanish-English Technical Terms.                 64mo, leather,  *1 00
+
+Montgomery, J. H. Electric Wiring Specifications.           16mo,  *1 00
+
+Moore, E. C. S. New Tables for the Complete Solution of
+  Ganguillet and Kutter's Formula.                           8vo,  *5 00
+
+Morecroft, J. H., and Hehre, F. W. Short Course
+  in Electrical Testing.                                     8vo,  *1 50
+
+Morgan, A. P. Wireless Telegraph Apparatus for Amateurs.    12mo,  *1 50
+
+Moses, A. J. The Characters of Crystals.                     8vo,  *2 00
+
+---- and Parsons, C. L. Elements of Mineralogy.              8vo,  *3 00
+
+Moss, S. A. Elements of Gas Engine Design. (Science
+  Series No. 121.)                                          16mo,   0 50
+
+---- The Lay-out of Corliss Valve Gears. (Science
+  Series No. 119.)                                          16mo,   0 50
+
+Mulford, A. C. Boundaries and Landmarks.                    12mo,  *1 00
+
+Mullin, J. P. Modern Moulding and Pattern-making.           12mo,   2 50
+
+Munby, A. E. Chemistry and Physics of Building
+  Materials. (Westminster Series.)                           8vo,  *2 00
+
+Murphy, J. G. Practical Mining.                             16mo,   1 00
+
+Murray, J. A. Soils and Manures. (Westminster Series.)       8vo,  *2 00
+
+
+Nasmith, J. The Student's Cotton Spinning.                   8vo,   3 00
+
+---- Recent Cotton Mill Construction.                       12mo,   2 50
+
+Neave, G. B., and Heilbron, I. M. Identification of
+  Organic Compounds.                                        12mo,  *1 25
+
+Neilson, R. M. Aeroplane Patents.                            8vo,  *2 00
+
+Nerz, F. Searchlights. Trans. by C. Rodgers.                 8vo,  *3 00
+
+Neuberger, H., and Noalhat, H. Technology of Petroleum.
+  Trans. by J. G. McIntosh.                                  8vo, *10 00
+
+Newall, J. W. Drawing, Sizing and Cutting Bevel-gears.       8vo,   1 50
+
+Newell, F. H., and Drayer, C. E. Engineering
+  as a Career                                        12mo, cloth,  *1 00
+                                                           paper,   0 75
+
+Newbeging, T. Handbook for Gas Engineers and Managers.       8vo,  *6 50
+
+Nicol, G. Ship Construction and Calculations.                8vo,  *5 00
+
+Nipher, F. E. Theory of Magnetic Measurements.              12mo,   1 00
+
+Nisbet, H. Grammar of Textile Design                         8vo,  *3 00
+
+Nolan, H. The Telescope. (Science Series No. 51.)           16mo,   0 50
+
+North, H. B. Laboratory Experiments in General Chemistry    12mo,  *1 00
+
+Nugent, E. Treatise on Optics                               12mo,   1 50
+
+
+O'Connor, H. The Gas Engineer's Pocketbook         12mo, leather,   3 50
+
+Ohm, G. S., and Lockwood, T. D. Galvanic Circuit.
+  Translated by William Francis. (Science Series
+  No. 102.)                                                 16mo,   0 50
+
+Olsen, J. C. Text-book of Quantitative Chemical Analysis     8vo,   3 50
+
+Olsson, A. Motor Control, in Turret Turning and Gun
+  Elevating. (U. S. Navy Electrical Series, No. 1.)  12mo, paper,  *0 50
+
+Ormsby, M. T. M. Surveying                                  12mo,   1 50
+
+Oudin, M. A. Standard Polyphase Apparatus and Systems        8vo,  *3 00
+
+Owen, D. Recent Physical Research                            8vo,  *1 50
+
+
+Pakes, W. C. C., and Nankivell, A. T. The Science of
+  Hygiene                                                    8vo,  *1 75
+
+Palaz, A. Industrial Photometry. Trans. by G. W.
+  Patterson, Jr.                                             8vo,  *4 00
+
+Pamely, C. Colliery Manager's Handbook                       8vo, *10 00
+
+Parker, P. A. M. The Control of Water                        8vo,  *5 00
+
+Parr, G. D. A. Electrical Engineering Measuring
+  Instruments                                                8vo,  *3 50
+
+Parry, E. J. Chemistry of Essential Oils and
+  Artificial Perfumes,                                     (_In Press._)
+
+---- Foods and Drugs. Two Volumes.
+    Vol. I. Chemical and Microscopical Analysis
+      of Foods and Drugs                                           *7 50
+    Vol. II. Sale of Food and Drugs Act                            *3 00
+
+---- and Coste, J. H. Chemistry of Pigments                  8vo,  *4 50
+
+Parry, L. Notes on Alloys                                    8vo,  *3 00
+
+---- Metalliferous Wastes                                    8vo,  *2 00
+
+---- Analysis of Ashes and Alloys                            8vo,  *2 00
+
+Parry, L. A. Risk and Dangers of Various Occupations         8vo,  *3 00
+
+Parshall, H. F., and Hobart, H. M. Armature Windings         4to,  *7 50
+
+---- Electric Railway Engineering                            4to, *10 00
+
+Parsons, J. L. Land Drainage                                 8vo,  *1 50
+
+Parsons, S. J. Malleable Cast Iron                           8vo,  *2 50
+
+Partington, J. R. Higher Mathematics for Chemical Students  12mo,  *2 00
+
+---- Textbook of Thermodynamics                              8vo,  *4 00
+
+Passmore, A. C. Technical Terms Used in Architecture         8vo,  *3 50
+
+Patchell, W. H. Electric Power in Mines                      8vo,  *4 00
+
+Paterson, G. W. L. Wiring Calculations                      12mo,  *2 00
+
+---- Electric Mine Signalling Installations                 12mo,  *1 50
+
+Patterson, D. The Color Printing of Carpet Yarns             8vo,  *3 50
+
+---- Color Matching on Textiles                              8vo,  *3 00
+
+---- Textile Color Mixing                                    8vo,  *3 00
+
+Paulding, C. P. Condensation of Steam in Covered and
+  Bare Pipes                                                 8vo,  *2 00
+
+---- Transmission of Heat through Cold-storage Insulation   12mo,  *1 00
+
+Payne, D. W. Iron Founders' Handbook                         8vo,  *4 00
+
+Peckham, S. F. Solid Bitumens                                8vo,  *5 00
+
+Peddie, R. A. Engineering and Metallurgical Books           12mo,  *1 50
+
+Peirce, B. System of Analytic Mechanics                      4to,  10 00
+
+---- Linnear Associative Algebra                             4to,   3 00
+
+Pendred, V. The Railway Locomotive. (Westminster Series.)    8vo,  *2 00
+
+Perkin, F. M. Practical Methods of Inorganic
+  Chemistry                                                 12mo,  *1 00
+
+Perrin, J. Atoms                                             8vo,  *2 50
+
+---- and Jaggers, E. M. Elementary Chemistry                12mo,  *1 00
+
+Perrine, F. A. C. Conductors for Electrical
+  Distribution                                               8vo,  *3 50
+
+Petit, G. White Lead and Zinc White Paints                   8vo,  *1 50
+
+Petit, R. How to Build an Aeroplane. Trans. by
+  T. O'B. Hubbard, and J. H. Ledeboer                        8vo,  *1 50
+
+Pettit, Lieut. J. S. Graphic Processes. (Science
+  Series No. 76.)                                           16mo,   0 50
+
+Philbrick, P. H. Beams and Girders. (Science Series
+  No. 88.)                                                  16mo,
+
+Phillips, J. Gold Assaying                                   8vo,  *2 50
+
+---- Dangerous Goods                                         8vo,   3 50
+
+Phin, J. Seven Follies of Science                           12mo,  *1 25
+
+Pickworth, C. N. The Indicator Handbook. Two
+  Volumes                                             12mo, each,   1 50
+
+---- Logarithms for Beginners                       12mo, boards,   0 50
+
+---- The Slide Rule                                         12mo,   1 00
+
+Plattner's Manual of Blow-pipe Analysis. Eighth
+  Edition, revised. Trans. by H. B. Cornwall                 8vo,  *4 00
+
+Plympton, G. W. The Aneroid Barometer. (Science
+  Series No. 35.)                                           16mo,   0 50
+
+---- How to become an Engineer. (Science Series No.
+  100.)                                                     16mo,   0 50
+
+---- Van Nostrand's Table Book,  (Science Series No.
+  104.)                                                     16mo,   0 50
+
+Pochet, M. L. Steam Injectors. Translated from the
+  French. (Science Series No. 29.)                          16mo,   0 50
+
+Pocket Logarithms to Four Places. (Science Series No.
+  65.)                                                      16mo,   0 50
+                                                         leather,   1 00
+
+Polleyn, F. Dressings and Finishings for Textile
+  Fabrics                                                    8vo,  *3 00
+
+Pope, F. G. Organic Chemistry                               12mo,  *2 25
+
+Pope, F. L. Modern Practice of the Electric Telegraph        8vo,   1 50
+
+Popplewell, W. C. Prevention of Smoke                        8vo,  *3 50
+
+---- Strength of Materials                                   8vo,  *1 75
+
+Porritt, B. D. The Chemistry of Rubber. (Chemical
+  Monographs, No. 3.)                                       12mo,  *0 75
+
+Porter, J. R. Helicopter Flying Machine                     12mo,  *1 25
+
+Potts, H. E. Chemistry of the Rubber Industry.
+  (Outlines of Industrial Chemistry)                         8vo,  *2 50
+
+Practical Compounding of Oils, Tallow and Grease             8vo,  *3 50
+
+Pratt, K. Boiler Draught                                    12mo,  *1 25
+
+---- High Speed Steam Engines                                8vo,  *2 00
+
+Pray, T., Jr. Twenty Years with the Indicator                8vo,   2 50
+
+---- Steam Tables and Engine Constant                        8vo,   2 00
+
+Prelini, C. Earth and Rock Excavation                        8vo,  *3 00
+
+---- Graphical Determination of Earth Slopes                 8vo,  *2 00
+
+---- Tunneling. New Edition                                  8vo,  *3 00
+
+---- Dredging. A Practical Treatise                          8vo,  *3 00
+
+Prescott, A. B. Organic Analysis                             8vo,   5 00
+
+Prescott, A. B., and Johnson, O. C. Qualitative
+  Chemical Analysis                                          8vo,  *3 50
+
+Prescott, A. B., and Sullivan, E. C. First Book in
+  Qualitative Chemistry                                     12mo,  *1 50
+
+Prideaux, E. B. R. Problems in Physical Chemistry            8vo,  *2 00
+
+Primrose, G. S. C. Zinc. (Metallurgy Series.)              (_In Press._)
+
+Prince, G. T. Flow of Water                                 12mo,  *2 00
+
+Pullen, W. W. F. Application of Graphic Methods to
+  the Design of Structures                                  12mo,  *2 50
+
+---- Injectors: Theory, Construction and Working            12mo,  *1 50
+
+---- Indicator Diagrams                                      8vo,  *2 50
+
+---- Engine Testing                                          8vo,  *4 50
+
+Putsch, A. Gas and Coal-dust Firing                          8vo,  *3 00
+
+Pynchon, T. R. Introduction to Chemical Physics              8vo,   3 00
+
+
+Rafter G. W. Mechanics of Ventilation. (Science Series
+  No. 33.)                                                  16mo,   0 50
+
+---- Potable Water. (Science Series No. 103.)               16mo,   0 50
+
+---- Treatment of Septic Sewage. (Science Series
+  No. 118.)                                                 16mo,   0 50
+
+Rafter, G. W., and Baker, M. N. Sewage Disposal in
+  the United States.                                         4to,  *6 00
+
+Raikes, H. P. Sewage Disposal Works                          8vo,  *4 00
+
+Randau, P. Enamels and Enamelling                            8vo,  *4 00
+
+Rankine, W. J. M. Applied Mechanics                          8vo,   5 00
+
+---- Civil Engineering                                       8vo,   6 50
+
+---- Machinery and Millwork                                  8vo,   5 00
+
+---- The Steam-engine and Other Prime Movers                 8vo,   5 00
+
+Rankine, W. J. M., and Bamber, E. F. A Mechanical
+  Text-book                                                  8vo,   3 50
+
+Ransome, W. R. Freshman Mathematics                         12mo,  *1 35
+
+Raphael, F. C. Localization of Faults in Electric
+  Light and Power Mains                                      8vo,   3 50
+
+Rasch, E. Electric Arc Phenomena. Trans. by K. Tornberg      8vo,  *2 00
+
+Rateau, A. Flow of Steam through Nozzles and Orifices.
+  Trans. by H. B. Brydon                                     8vo,  *1 50
+
+Rathbone, R. L. B. Simple Jewellery                          8vo,  *2 00
+
+Rausenberger, F. The Theory of the Recoil of Guns            8vo,  *4 50
+
+Rautenstrauch, W. Notes on the Elements of Machine
+  Design                                             8vo, boards,  *1 50
+
+Rautenstrauch, W., and Williams, J. T. Machine Drafting
+  and Empirical Design.
+    Part I. Machine Drafting                                 8vo,  *1 25
+    Part II. Empirical Design                        (_In Preparation._)
+
+Raymond, E. B. Alternating Current Engineering              12mo,  *2 50
+
+Rayner, H. Silk Throwing and Waste Silk Spinning             8vo,  *2 50
+
+Recipes for the Color, Paint, Varnish, Oil, Soap and
+  Drysaltery Trades                                          8vo,  *3 50
+
+Recipes for Flint Glass Making                              12mo,  *4 50
+
+Redfern, J. B., and Savin, J. Bells, Telephones
+  (Installation Manuals Series.)                            16mo,  *0 50
+
+Redgrove, H. S. Experimental Mensuration                    12mo,  *1 25
+
+Redwood, B. Petroleum. (Science Series No. 92.)             16mo,   0 50
+
+Reed, S. Turbines Applied to Marine Propulsion                     *5 00
+
+Reed's Engineers' Handbook                                   8vo,  *6 00
+
+---- Key to the Nineteenth Edition of Reed's
+  Engineers' Handbook                                        8vo,  *3 00
+
+---- Useful Hints to Sea-going Engineers                    12mo,   1 50
+
+Reid, E. E. Introduction to Research in Organic
+  Chemistry                                                (_In Press._)
+
+Reid, H. A. Concrete and Reinforced Concrete
+  Construction                                               8vo,  *5 00
+
+Reinhardt, C. W. Lettering for Draftsmen, Engineers,
+  and Students                                oblong 4to, boards,   1 00
+
+Reinhardt, C. W. The Technic of Mechanical Drafting,
+                                             oblong, 4to, boards,  *1 00
+
+Reiser, F. Hardening and Tempering of Steel. Trans. by A.
+  Morris and H. Robson                                      12mo,  *2 50
+
+Reiser, N. Faults in the Manufacture of Woolen Goods.
+  Trans. by A. Morris and H. Robson                          8vo,  *2 50
+
+---- Spinning and Weaving Calculations                       8vo,  *5 00
+
+Renwick, W. G. Marble and Marble Working                     8vo,   5 00
+
+Reuleaux, F. The Constructor. Trans. by H. H. Suplee         4to,  *4 00
+
+Reuterdahl, A. Theory and Design of Reinforced
+  Concrete Arches.                                           8vo,  *2 00
+
+Rey, Jean. The Range of Electric Searchlight Projectors      8vo,  *4 50
+
+Reynolds, O., and Idell, F. E. Triple Expansion Engines.
+  (Science Series No. 99.)                                  16mo,   0 50
+
+Rhead, G. F. Simple Structural Woodwork                     12mo,  *1 00
+
+Rhodes, H. J. Art of Lithography                             8vo,   3 50
+
+Rice, J. M., and Johnson, W. W. A New Method of Obtaining
+  the Differential of Functions                             12mo,   0 50
+
+Richards, W. A. Forging of Iron and Steel                   12mo,   1 50
+
+Richards, W. A., and North, H. B. Manual of Cement Testing  12mo,  *1 50
+
+Richardson, J. The Modern Steam Engine                       8vo,  *3 50
+
+Richardson, S. S. Magnetism and Electricity                 12mo,  *2 00
+
+Rideal, S. Glue and Glue Testing                             8vo,  *4 00
+
+Rimmer, E. J. Boiler Explosions, Collapses and Mishaps       8vo,  *1 75
+
+Rings, F. Concrete in Theory and Practice                   12mo,  *2 50
+
+---- Reinforced Concrete Bridges                             4to,  *5 00
+
+Ripper, W. Course of Instruction in Machine Drawing        folio,  *6 00
+
+Roberts, F. C. Figure of the Earth. (Science Series
+  No. 79.)                                                  16mo,   0 50
+
+Roberts, J., Jr. Laboratory Work in Electrical Engineering   8vo,  *2 00
+
+Robertson, L. S. Water-tube Boilers                          8vo,   2 00
+
+Robinson, J. B. Architectural Composition                    8vo,  *2 50
+
+Robinson, S. W. Practical Treatise on the Teeth of Wheels.
+  (Science Series No. 24.)                                  16mo,   0 50
+
+---- Railroad Economics. (Science Series No. 59.)           16mo,   0 50
+
+---- Wrought Iron Bridge Members. (Science Series No. 60.)  16mo,   0 50
+
+Robson, J. H. Machine Drawing and Sketching                  8vo,  *1 50
+
+Roebling, J. A. Long and Short Span Railway Bridges        folio,  25 00
+
+Rogers, A. A Laboratory Guide of Industrial Chemistry      (_In Press._)
+
+---- Elements of Industrial Chemistry                       12mo,  *3 00
+
+---- Manual of Industrial Chemistry                          8vo,  *5 00
+
+Rogers, F. Magnetism of Iron Vessels. (Science Series
+  No. 30.).                                                 16mo,   0 50
+
+Rohland, P. Colloidal and Crystalloidal State of Matter.
+  Trans. by W. J. Britland and H. E. Potts                  12mo,  *1 25
+
+Rollinson, C. Alphabets                             Oblong, 12mo,  *1 00
+
+Rose, J. The Pattern-makers' Assistant                       8vo,   2 50
+
+---- Key to Engines and Engine-running                      12mo,   2 50
+
+Rose, T. K. The Precious Metals. (Westminster Series.)       8vo,  *2 00
+
+Rosenhain, W. Glass Manufacture. (Westminster Series.)       8vo,  *2 00
+
+---- Physical Metallurgy, An Introduction to. (Metallurgy
+  Series.)                                                   8vo,  *3 50
+
+Roth, W. A. Physical Chemistry                               8vo,  *2 00
+
+Rowan, F. J. Practical Physics of the Modern Steam-boiler    8vo,  *3 00
+
+---- and Idell, F. E. Boiler Incrustation and Corrosion.
+  (Science Series No. 27.)                                  16mo,   0 50
+
+Roxburgh, W. General Foundry Practice. (Westminster
+  Series.).                                                  8vo,  *2 00
+
+Ruhmer, E. Wireless Telephony. Trans. by J. Erskine-Murray.  8vo,  *3 50
+
+Russell, A. Theory of Electric Cables and Networks           8vo,  *3 00
+
+Rutley, F. Elements of Mineralogy                           12mo,  *1 25
+
+
+Sanford, P. G. Nitro-explosives                              8vo,  *4 00
+
+Saunders, C. H. Handbook of Practical Mechanics             16mo,   1 00
+                                                         leather,   1 25
+
+Sayers, H. M. Brakes for Tram Cars                           8vo,  *1 25
+
+Scheele, C. W. Chemical Essays                               8vo,  *2 00
+
+Scheithauer, W. Shale Oils and Tars                          8vo,  *3 50
+
+Scherer, R. Casein. Trans. by C. Salter                      8vo,  *3 00
+
+Schidrowitz, P. Rubber, Its Production and Industrial Uses   8vo,  *5 00
+
+Schindler, K. Iron and Steel Construction Works             12mo,  *1 25
+
+Schmall, C. N. First Course in Analytic Geometry,
+  Plane and Solid.                            12mo, half leather,  *1 75
+
+Schmeer, L. Flow of Water                                    8vo,  *3 00
+
+Schumann, F. A Manual of Heating and Ventilation   12mo, leather,   1 50
+
+Schwarz, E. H. L. Causal Geology                             8vo,  *2 50
+
+Schweizer, V. Distillation of Resins                         8vo,  *3 50
+
+Scott, W. W. Qualitative Analysis. A Laboratory Manual       8vo,  *1 50
+
+---- Standard Methods of Chemical Analysis                   8vo,  *6 00
+
+Scribner, J. M. Engineers' and Mechanics'
+  Companion                                        16mo, leather,   1 50
+
+Scudder, H. Electrical Conductivity and Ionization Constants
+  of Organic Compounds                                       8vo,  *3 00
+
+Searle, A. B. Modern Brickmaking                             8vo,  *5 00
+
+---- Cement, Concrete and Bricks                             8vo,  *3 00
+
+Searle, G. M. "Sumners' Method."  Condensed and Improved.
+  (Science Series No. 124.)                                 16mo,   0 50
+
+Seaton, A. E. Manual of Marine Engineering                   8vo,   8 00
+
+Seaton, A. E., and Rounthwaite, H. M. Pocket-book of
+  Marine Engineering                               16mo, leather,   3 50
+
+Seeligmann, T., Torrilhon, G. L., and Falconnet, H. India
+  Rubber and Gutta Percha. Trans. by J. G. McIntosh          8vo,  *5 00
+
+Seidell, A. Solubilities of Inorganic and Organic
+  Substances                                                 8vo,   4 50
+
+Seligman, B. Aluminum. (Metallurgy Series.)                (_In Press._)
+
+Sellew, W. H. Steel Rails                                    4to, *10 00
+
+---- Railway Maintenance Engineering                        12mo,  *2 50
+
+Senter, G. Outlines of Physical Chemistry                   12mo,  *1 75
+
+---- Text-book of Inorganic Chemistry                       12mo,  *1 75
+
+Sever, G. F. Electric Engineering Experiments        8vo, boards,  *1 00
+
+Sever, G. F., and Townsend, F. Laboratory and Factory
+  Tests in Electrical Engineering                            8vo,  *2 50
+
+Sewall, C. H. Wireless Telegraphy                            8vo,  *2 00
+
+---- Lessons in Telegraphy                                  12mo,  *1 00
+
+Sewell, T. The Construction of Dynamos                       8vo,  *3 00
+
+Sexton, A. H. Fuel and Refractory Materials                 12mo,  *2 50
+
+---- Chemistry of the Materials of Engineering              12mo,  *2 50
+
+---- Alloys (Non-Ferrous)                                    8vo,  *3 00
+
+Sexton, A. H., and Primrose, J. S. G. The Metallurgy of
+  Iron and Steel.                                            8vo,  *6 50
+
+Seymour, A. Modern Printing Inks                             8vo,  *2 00
+
+Shaw, Henry S. H. Mechanical Integrators. (Science
+  Series No. 83.)                                           16mo,   0 50
+
+Shaw, S. History of the Staffordshire Potteries              8vo,   2 00
+
+---- Chemistry of Compounds Used in Porcelain Manufacture    8vo,  *5 00
+
+Shaw, T. R. Driving of Machine Tools                        12mo,  *2 00
+
+Shaw, W. N. Forecasting Weather                              8vo,  *3 50
+
+Sheldon, S., and Hausmann, E. Direct Current Machines       12mo,  *2 50
+
+---- Alternating Current Machines                           12mo,  *2 50
+
+Sheldon, S., and Hausmann, E. Electric Traction and
+  Transmission Engineering                                  12mo,  *2 50
+
+---- Physical Laboratory Experiments, for Engineering
+  Students                                                   8vo,  *1 25
+
+Shields, J. E. Notes on Engineering Construction            12mo,   1 50
+
+Shreve, S. H. Strength of Bridges and Roofs                  8vo,   3 50
+
+Shunk, W. F. The Field Engineer                    12mo, morocco,   2 50
+
+Simmons, W. H., and Appleton, H. A. Handbook of
+  Soap Manufacture,                                          8vo,  *3 00
+
+Simmons, W. H., and Mitchell, C. A. Edible Fats and Oils     8vo,  *3 00
+
+Simpson, G. The Naval Constructor                  12mo, morocco,  *5 00
+
+Simpson, W. Foundations                               8vo. (_In Press._)
+
+Sinclair, A. Development of the Locomotive
+  Engine                                       8vo, half leather,   5 00
+
+Sindall, R. W. Manufacture of Paper. (Westminster Series.)   8vo,  *2 00
+
+Sindall, R. W., and Bacon, W. N. The Testing of Wood Pulp    8vo,  *2 50
+
+Sloane, T. O'C. Elementary Electrical Calculations          12mo,  *2 00
+
+Smallwood, J. C. Mechanical Laboratory Methods. (Van
+  Nostrand's Textbooks)                            12mo, leather,  *2 50
+
+Smith, C. A. M. Handbook of Testing, MATERIALS               8vo,  *2 50
+
+Smith, C. A. M., and Warren, A. G. New Steam Tables          8vo,  *1 25
+
+Smith, C. F. Practical Alternating Currents and Testing      8vo,  *2 50
+
+---- Practical Testing of Dynamos and Motors                 8vo,  *2 00
+
+Smith, F. A. Railway Curves                                 12mo,  *1 00
+
+---- Standard Turnouts on American Railroads                12mo,  *1 00
+
+---- Maintenance of Way Standards                           12mo,  *1 50
+
+Smith, F. E. Handbook of General Instruction for
+  Mechanics                                                 12mo,   1 50
+
+Smith, H. G. Minerals and the Microscope                    12mo,  *1 25
+
+Smith, J. C. Manufacture of Paint                            8vo,  *3 50
+
+Smith, R. H. Principles of Machine Work                     12mo,
+
+---- Advanced Machine Work                                  12mo,  *3 00
+
+Smith, W. Chemistry of Hat Manufacturing                    12mo,  *3 00
+
+Snell, A. T. Electric Motive Power                           8vo,  *4 00
+
+Snow, W. G. Pocketbook of Steam Heating and Ventilation.   (_In Press._)
+
+Snow, W. G., and Nolan, T. Ventilation of Buildings.
+  (Science Series No. 5.)                                   16mo,   0 50
+
+Soddy, F. Radioactivity                                      8vo,  *3 00
+
+Solomon, M. Electric Lamps. (Westminster Series.)            8vo,  *2 00
+
+Somerscales, A. N. Mechanics for Marine Engineers           12mo,  *2 00
+
+---- Mechanical and Marine Engineering Science               8vo,  *5 00
+
+Sothern, J. W. The Marine Steam Turbine                      8vo,  *6 00
+
+---- Verbal Notes and Sketches for Marine Engineers          8vo,  *7 50
+
+Sothern, J. W., and Sothern, R. M. Elementary
+  Mathematics for Marine Engineers                          12mo,  *1 50
+
+---- Simple Problems in Marine Engineering Design           12mo,  *1 50
+
+Southcombe, J. E. Chemistry of the Oil Industries.
+  (Outlines of Industrial Chemistry.)                        8vo,  *3 00
+
+Soxhlet, D. H. Dyeing and Staining Marble. Trans.
+  by A. Morris and H. Robson                                 8vo,  *2 50
+
+Spangenburg, L. Fatigue of Metals. Translated by
+  S. H. Shreve. (Science Series No. 23.)                    16mo,   0 50
+
+Specht, G. J., Hardy, A. S., McMaster, J. B., and
+  Walling. Topographical Surveying. (Science Series
+  No. 72.)                                                  16mo,   0 50
+
+Spencer, A. S. Design of Steel-Framed Sheds                  8vo,  *3 50
+
+Speyers, C. L. Text-book of Physical Chemistry               8vo,  *1 50
+
+Spiegel, L. Chemical Constitution and Physiological
+  Action. (Trans. by C. Luedeking and A. C. Boylston.)      12mo,  *1 25
+
+Sprague, E. H. Hydraulics                                   12mo,   1 50
+
+---- Elements of Graphic Statics                             8vo,   2 00
+
+---- Stability of Masonry                                   12mo,   1 50
+
+---- Elementary Mathematics for Engineers                   12mo,  *1 50
+
+Stahl, A. W. Transmission of Power. (Science Series
+  No. 28.)                                                  16mo,
+
+Stahl, A. W., and Woods, A. T. Elementary Mechanism         12mo,  *2 00
+
+Staley, C., and Pierson, G. S. The Separate System of
+  Sewerage                                                   8vo,  *3 00
+
+Standage, H. C. Leatherworkers' Manual                       8vo,  *3 50
+
+---- Sealing Waxes, Wafers, and Other Adhesives              8vo,  *2 00
+
+---- Agglutinants of all Kinds for all Purposes             12mo,  *3 50
+
+Stanley, H. Practical Applied Physics                      (_In Press._)
+
+Stansbie, J. H. Iron and Steel. (Westminster Series.)        8vo,  *2 00
+
+Steadman, F. M. Unit Photography                            12mo,  *2 00
+
+Stecher, G. E. Cork. Its Origin and Industrial Uses         12mo,   1 00
+
+Steinman, D. B. Suspension Bridges and Cantilevers.
+  (Science Series No. 127.)                                         0 50
+
+---- Melan's Steel Arches and Suspension Bridges             8vo,  *3 00
+
+Stevens, H. P. Paper Mill Chemist                           16mo,  *2 50
+
+Stevens, J. S. Theory of Measurements                       12mo,  *1 25
+
+Stevenson, J. L. Blast-Furnace Calculations        12mo, leather,  *2 00
+
+Stewart, G. Modern Steam Traps                              12mo,  *1 25
+
+Stiles, A. Tables for Field Engineers                       12mo,   1 00
+
+Stodola, A. Steam Turbines. Trans. by L. C.
+  Loewenstein                                                8vo,  *5 00
+
+Stone, H. The Timbers of Commerce                            8vo,   3 50
+
+Stopes, M. Ancient Plants                                    8vo,  *2 00
+
+---- The Study of Plant Life                                 8vo,  *2 00
+
+Sudborough, J. J., and James, T. C. Practical Organic
+  Chemistry                                                 12mo,  *2 00
+
+Suffling, E. R. Treatise on the Art of Glass Painting        8vo,  *3 50
+
+Sullivan, T. V., and Underwood, N. Testing and
+  Valuation of Building and Engineering Materials          (_In Press._)
+
+Sur, F. J. S. Oil Prospecting and Extracting                 8vo,  *1 00
+
+Svenson, C. L. Handbook on Piping                          (_In Press._)
+
+Swan, K. Patents, Designs and Trade Marks.
+  (Westminster Series.)                                      8vo,  *2 00
+
+Swinburne, J., Wordingham, C. H., and Martin, T. C.
+  Electric Currents. (Science Series No. 109.)              16mo,   0 50
+
+Swoope, C. W. Lessons in Practical Electricity              12mo,  *2 00
+
+
+Tailfer, L. Bleaching Linen and Cotton Yarn and Fabrics      8vo,   6 00
+
+Tate, J. S. Surcharged and Different Forms of
+  Retaining-walls. (Science Series No. 7.)                  16mo,   0 50
+
+Taylor, F. N. Small Water Supplies                          12mo,  *2 50
+
+---- Masonry in Civil Engineering                            8vo,  *2 50
+
+Taylor, T. U. Surveyor's Handbook                  12mo, leather,  *2 00
+
+---- Backbone of Perspective                                12mo,  *1 00
+
+Taylor, W. P. Practical Cement Testing                       8vo,  *3 00
+
+Templeton, W. Practical Mechanic's Workshop
+  Companion                                        12mo, morocco,   2 00
+
+Tenney, E. H. Test Methods for Steam Power Plants.
+  (Van Nostrand's Textbooks.)                               12mo,  *2 50
+
+Terry, H. L. India Rubber and its Manufacture.
+  (Westminster Series.)                                      8vo,  *2 00
+
+Thayer, H. R. Structural Design.                             8vo.
+    Vol. I. Elements of Structural Design                          *2 00
+    Vol. II. Design of Simple Structures                           *4 00
+    Vol. III. Design of Advanced Structures          (_In Preparation._)
+
+---- Foundations and Masonry                         (_In Preparation._)
+
+Thiess, J. B., and Joy, G. A. Toll Telephone Practice        8vo,  *3 50
+
+Thom, C., and Jones, W. H. Telegraphic Connections  oblong, 12mo,   1 50
+
+Thomas, C. W. Paper-makers' Handbook                       (_In Press._)
+
+Thompson, A. B. Oil Fields of Russia                         4to,  *7 50
+
+---- Oil Field Development                                          7 50
+
+Thompson, S. P. Dynamo Electric Machines. (Science
+  Series No. 75.)                                           16mo,   0 50
+
+Thompson, W. P. Handbook of Patent Law of All
+  Countries                                                 16mo,   1 50
+
+Thomson, G. Modern Sanitary Engineering                     12mo,  *3 00
+
+Thomson, G. S. Milk and Cream Testing                       12mo,  *1 75
+
+---- Modern Sanitary Engineering, House Drainage, etc.       8vo,  *3 00
+
+Thornley, T. Cotton Combing Machines                         8vo,  *3 00
+
+---- Cotton Waste                                            8vo,  *3 00
+
+---- Cotton Spinning.                                        8vo.
+    First Year                                                     *1 50
+    Second Year                                                    *3 00
+    Third Year                                                     *2 50
+
+Thurso, J. W. Modern Turbine Practice                        8vo,  *4 00
+
+Tidy, C. Meymott. Treatment of Sewage. (Science Series
+  No. 94.)                                                  16mo,   0 50
+
+Tillmans, J. Water Purification and Sewage Disposal.
+  Trans. by Hugh S. Taylor                                   8vo,  *2 00
+
+Tinney, W. H. Gold-mining Machinery                          8vo,  *3 00
+
+Titherley, A. W. Laboratory Course of Organic Chemistry      8vo,  *2 00
+
+Tizard, H. T. Indicators                                   (_In Press._)
+
+Toch, M. Chemistry and Technology of Paints                  8vo,  *4 00
+
+---- Materials for Permanent Painting                       12mo,  *2 00
+
+Tod, J., and McGibbon, W. C. Marine Engineers' Board
+  of Trade Examinations                                      8vo,  *2 00
+
+Todd, J., and Whall, W. B. Practical Seamanship              8vo,   8 00
+
+Tonge, J. Coal. (Westminster Series.)                        8vo,  *2 00
+
+Townsend, F. Alternating Current Engineering         8vo, boards,  *0 75
+
+Townsend, J. S. Ionization of Gases by Collision             8vo,  *1 25
+
+Transactions of the American Institute of Chemical
+  Engineers, 8vo. Eight volumes now ready. Vol. I.
+  to IX., 1908-1916                                    8vo, each,   6 00
+
+Traverse Tables. (Science Series No. 115.)                  16mo,   0 50
+                                                         morocco,   1 00
+
+Treiber, E. Foundry Machinery. Trans. by C. Salter          12mo,   1 50
+
+Trinks, W., and Housum, C. Shaft Governors. (Science
+  Series No. 122.)                                          16mo,   0 50
+
+Trowbridge, W. P. Turbine Wheels. (Science Series No.
+  44.)                                                      16mo,   0 50
+
+Tucker, J. H. A Manual of Sugar Analysis                     8vo,   3 50
+
+Tunner, P. A. Treatise on Roll-turning. Trans. by
+  J. B. Pearse.                        8vo, text and folio atlas,  10 00
+
+Turnbull, Jr., J., and Robinson, S. W. A Treatise on
+  the Compound Steam-engine. (Science Series No. 8.)        16mo,
+
+Turner, H. Worsted Spinners' Handbook                       12mo,  *2 00
+
+Turrill, S. M. Elementary Course in Perspective             12mo,  *1 25
+
+Twyford, H. B. Purchasing                                    8vo,  *3 00
+
+Tyrrell, H. G. Design and Construction of Mill
+  Buildings                                                  8vo,  *4 00
+
+---- Concrete Bridges and Culverts                 16mo, leather,  *3 00
+
+---- Artistic Bridge Design                                  8vo,  *3 00
+
+
+Underhill, C. R. Solenoids, Electromagnets and
+  Electromagnetic Windings                                  12mo,  *2 00
+
+Underwood, N., and Sullivan, T. V. Chemistry and
+  Technology of Printing Inks                                8vo,  *3 00
+
+Urquhart, J. W. Electro-plating                             12mo,   2 00
+
+---- Electrotyping                                          12mo,   2 00
+
+Usborne, P. O. G. Design of Simple Steel Bridges             8vo,  *4 00
+
+
+Vacher, F. Food Inspector's Handbook                        12mo,
+
+Van Nostrand's Chemical Annual. Third issue 1913   leather, 12mo,  *2 50
+
+---- Year Book of Mechanical Engineering Data              (_In Press._)
+
+Van Wagenen, T. F. Manual of Hydraulic Mining               16mo,   1 00
+
+Vega, Baron Von. Logarithmic Tables                   8vo, cloth,   2 00
+                                                    half morocco,   2 50
+
+Vincent, C. Ammonia and its Compounds. Trans. by
+  M. J. Salter                                               8vo,  *2 00
+
+Volk, C. Haulage and Winding Appliances                      8vo,  *4 00
+
+Von Georgievics, G. Chemical Technology of Textile
+  Fibres. Trans. by C. Salter                                8vo,  *4 50
+
+---- Chemistry of Dyestuffs. Trans. by C. Salter             8vo,  *4 50
+
+Vose, G. L. Graphic Method for Solving Certain
+  Questions in Arithmetic and Algebra (Science
+  Series No. 16.)                                           16mo,   0 50
+
+Vosmaer, A. Ozone                                            8vo,  *2 50
+
+
+Wabner, R. Ventilation in Mines. Trans. by C. Salter         8vo,  *4 50
+
+Wade, E. J. Secondary Batteries                              8vo,  *4 00
+
+Wadmore, T. M. Elementary Chemical Theory                   12mo,  *1 50
+
+Wadsworth, C. Primary Battery Ignition                      12mo,  *0 50
+
+Wagner, E. Preserving Fruits, Vegetables, and Meat          12mo,  *2 50
+
+Wagner, J. B. A Treatise on the Natural and Artificial
+  Processes of Wood Seasoning                         8vo, (_In Press._)
+
+Waldram, P. J. Principles of Structural Mechanics           12mo,  *3 00
+
+Walker, F. Aerial Navigation                                 8vo,   2 00
+
+---- Dynamo Building. (Science Series No. 98.)              16mo,   0 50
+
+Walker, J. Organic Chemistry for Students of Medicine        8vo,  *2 50
+
+Walker, S. F. Steam Boilers, Engines and Turbines            8vo,   3 00
+
+---- Refrigeration, Heating and Ventilation on
+  Shipboard                                                 12mo,  *2 00
+
+---- Electricity in Mining                                   8vo,  *3 50
+
+Wallis-Tayler, A. J. Bearings and Lubrication                8vo,  *1 50
+
+---- Aerial or Wire Ropeways                                 8vo,  *3 00
+
+---- Sugar Machinery                                        12mo,  *2 00
+
+Walsh, J. J. Chemistry and Physics of Mining and
+  Mine Ventilation,                                         12mo,  *2 00
+
+Wanklyn, J. A. Water Analysis                               12mo,   2 00
+
+Wansbrough, W. D. The A B C of the Differential
+  Calculus                                                  12mo,  *1 50
+
+---- Slide Valves                                           12mo,  *2 00
+
+Waring, Jr., G. E. Sanitary Conditions. (Science
+  Series No. 31.)                                           16mo,   0 50
+
+---- Sewerage and Land Drainage                                    *6 00
+
+---- Modern Methods of Sewage Disposal                      12mo,   2 00
+
+---- How to Drain a House                                   12mo,   1 25
+
+Warnes, A. R. Coal Tar Distillation                          8vo,  *3 00
+
+Warren, F. D. Handbook on Reinforced Concrete               12mo,  *2 50
+
+Watkins, A. Photography. (Westminster Series.)               8vo,  *2 00
+
+Watson, E. P. Small Engines and Boilers                     12mo,   1 25
+
+Watt, A. Electro-plating and Electro-refining of Metals      8vo,  *4 50
+
+---- Electro-metallurgy                                     12mo,   1 00
+
+---- The Art of Soap Making                                  8vo,   3 00
+
+---- Leather Manufacture                                     8vo,  *4 00
+
+---- Paper-Making                                            8vo,   3 00
+
+Webb, H. L. Guide to the Testing of Insulated Wires
+  and Cables                                                12mo,   1 00
+
+Webber, W. H. Y. Town Gas. (Westminster Series.)             8vo,  *2 00
+
+Weisbach, J. A Manual of Theoretical Mechanics               8vo,  *6 00
+                                                           sheep,  *7 50
+
+Weisbach, J., and Herrmann, G. Mechanics of Air
+  Machinery                                                  8vo,  *3 75
+
+Wells, M. B. Steel Bridge Designing                          8vo,  *2 50
+
+Weston, E. B. Loss of Head Due to Friction of Water
+  in Pipes                                                  12mo,  *1 50
+
+Wheatley, O. Ornamental Cement Work                          8vo,  *2 00
+
+Whipple, S. An Elementary and Practical Treatise on
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+White, C. H. Methods of Metallurgical Analysis. (Van
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+White, G. T. Toothed Gearing                                12mo,  *1 25
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+Wilda, H. Steam Turbines. Trans. by C. Salter               12mo,   1 50
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+Wilkinson, H. D. Submarine Cable Laying and Repairing        8vo,  *6 00
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+Williamson, J. Surveying                                     8vo,  *3 00
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+Williamson, R. S. On the Use of the Barometer                4to,  15 00
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+---- Practical Tables in Meteorology and Hypsometry          4to,   2 50
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+Wilson, F. J., and Heilbron, I. M. Chemical Theory
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+Wisser, Lieut. J. P. Explosive Materials. (Science
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+Wisser, Lieut. J. P. Modern Gun Cotton. (Science
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+Wolff, C. E. Modern Locomotive Practice                      8vo,  *4 20
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+Wood, De V. Luminiferous Aether. (Science Series No. 85)    16mo,   0 50
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+Wood, J. K. Chemistry of Dyeing. (Chemical Monographs
+  No. 2.)                                                   12mo,  *0 75
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+Worden, E. C. The Nitrocellulose Industry. Two Volumes       8vo, *10 00
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+---- Technology of Cellulose Esters. In 10 volumes. 8vo.
+    Vol. VIII. Cellulose Acetate                                   *5 00
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+Wren, H. Organometallic Compounds of Zinc and Magnesium.
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+Wright, T. W. Elements of Mechanics                          8vo,  *2 50
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+Wright, T. W., and Hayford, J. F. Adjustment
+  of Observations                                            8vo,  *3 00
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+Wynne, W. E., and Sparagen, W. Handbook of Engineering
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+Yoder, J. H., and Wharen, G. B. Locomotive Valves
+  and Valve Gears                                            8vo,  *3 00
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+Young, J. E. Electrical Testing for Telegraph Engineers      8vo,  *4 00
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+Zahner, R. Transmission of Power. (Science Series No. 40.)  16mo,
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+Zeidler, J., and Lustgarten, J. Electric Arc Lamps           8vo,  *2 00
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+Zeuner, A. Technical Thermodynamics. Trans. by
+  J. F. Klein. Two Volumes                                   8vo,  *8 00
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+Zimmer, G. F. Mechanical Handling and Storing
+  of Materials                                               4to, *12 50
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+Zipser, J. Textile Raw Materials. Trans. by C. Salter        8vo,  *5 00
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+Zur Nedden, F. Engineering Workshop Machines and
+  Processes. Trans. by J. A. Davenport                       8vo,  *2 00
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+page 018--typo fixed: changed 'Oregan' to 'Oregon'
+page 027--fixed: changed 'Michigian' to 'Michigan'
+page 046--typo fixed: changed 'resistence' to 'resistance'
+page 058--typo fixed: changed 'homus' to 'humus'
+page 069--typo fixed: changed 'resistence' to 'resistance'
+page 074--typo fixed: changed 'ilicijolia' to 'ilicifolia'
+page 084--typo fixed: changed 'Novia Scota' to 'Nova Scotia'
+page 086--typo fixed: changed 'visable' to 'visible'
+page 103--typo fixed: changed 'energed' to 'emerged'
+page 106--typo fixed: changed 'absolutley' to 'absolutely'
+page 110--typo fixed: changed 'has' to 'had'
+page 131--typo fixed: changed 'accomodate' to 'accommodate'
+page 163--typo fixed: changed 'hydrodeik' to 'hygrodeik'
+page 181--typo fixed: changed 'longitutudinal' to 'longitudinal'
+page 198--typo fixed: changed 'accomodate' to 'accommodate'
+page 202--typo fixed: changed 'ecomony' to 'economy'
+page 204--typo fixed: changed 'minumim' to 'minimum'
+page 239--typo fixed: changed 'horizonal' to 'horizontal'
+page 257--typo fixed: changed 'arrangment' to 'arrangement'
+page 266--typo fixed: changed 'applicances' to 'appliances'
+page 267--typo fixed: changed 'specialities' to 'specialties'
+page 267--typo fixed: changed 'theary' to 'theory'
+page 274--typo fixed: changed 'Annual of' to 'Annual or'
+
+
+
+
+
+
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