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diff --git a/.gitattributes b/.gitattributes new file mode 100644 index 0000000..6833f05 --- /dev/null +++ b/.gitattributes @@ -0,0 +1,3 @@ +* text=auto +*.txt text +*.md text diff --git a/18448-0.txt b/18448-0.txt new file mode 100644 index 0000000..78788ef --- /dev/null +++ b/18448-0.txt @@ -0,0 +1,6002 @@ +The Project Gutenberg EBook of Transactions of the American Society of +Civil Engineers, vol. LXX, Dec. 1910, by Herbert M. Wilson + +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: Transactions of the American Society of Civil Engineers, vol. LXX, Dec. 1910 + Federal Investigations of Mine Accidents, Structural + Materials and Fuels. Paper No. 1171 + +Author: Herbert M. Wilson + +Release Date: May 25, 2006 [EBook #18448] + +Language: English + +Character set encoding: UTF-8 + +*** START OF THIS PROJECT GUTENBERG EBOOK SOCIETY OF CIVIL ENGINEERS *** + + + + +Produced by Louise Hope, Juliet Sutherland and the Online +Distributed Proofreading Team at http://www.pgdp.net + + + + + + [Transcriber’s Note: + All footnotes are grouped at the end of the file. Those that include + non-bibliographic information are _also_ shown after their referring + paragraph. + This UTF-8 file includes a few less common fractions such as ⅛ and ⅔. + Readers who cannot see these characters may prefer the Latin-1 version + of the file.] + + * * * * * + + AMERICAN SOCIETY OF CIVIL ENGINEERS + Instituted 1852 + + TRANSACTIONS + + Paper No. 1171 + + FEDERAL INVESTIGATIONS OF MINE ACCIDENTS, + STRUCTURAL MATERIALS, AND FUELS.[1] + + By HERBERT M. WILSON, M. Am. Soc. C. E. + + With Discussion by Messrs. KENNETH ALLEN, + HENRY KREISINGER, WALTER O. SNELLING, + A. BARTOCCINI, H. G. STOTT, B. W. DUNN, + and HERBERT M. WILSON. + + +INTRODUCTION. + +The mine disaster, which occurred at Cherry, Ill., on November 13th, +1909, when 527 men were in the mine, resulting in the entombment of 330 +men, of whom 310 were killed, has again focused public attention on the +frequent recurrence of such disasters and their appalling consequences. +Interest in the possible prevention of such disasters, and the possible +means of combating subsequent mine fires and rescuing the imprisoned +miners, has been heightened as it was not even by the series of three +equally extensive disasters which occurred in 1907, for the reason that, +after the Cherry disaster, 20 men were rescued alive after an entombment +of one week, when practically all hope of rescuing any of the miners had +been abandoned. + +This accident, occurring, as it does, a little more than 1½ years after +the enactment of legislation by Congress instructing the Director of the +United States Geological Survey to investigate the causes and possible +means of preventing the loss of life in coal-mining operations, makes +this an opportune time to review what has been done by the Geological +Survey during this time, toward carrying out the intent of this Act. + +It may be stated with confidence, that had such a disaster occurred a +year or more ago, all the entombed men must have perished, as it would +have been impossible to enter the mine without the protection afforded +by artificial respiratory apparatus. Moreover, but for the presence of +the skilled corps of Government engineers, experienced by more than a +year’s training in similar operations in more than twenty disasters, the +mine would have been sealed until the fire had burned out, and neither +the dead, nor those who were found alive, would have been recovered for +many weeks. In the interval great suffering and loss would have been +inflicted on the miners, because of enforced idleness, and on the mine +owners because of continued inability to re-open and resume operations. + +_Character of the Work._--The United States Geological Survey has been +engaged continuously since 1904 in conducting investigations relating to +structural materials, such as stone, clay, cement, etc., and in making +tests and analyses of the coals, lignites, and other mineral fuel +substances, belonging to, and for the use of, the Government. + +Incidentally, the Survey has been considering means to increase +efficiency in the use of these resources as fuels and structural +materials, in the hope that the investigations will lead to their best +utilization. + +These inquiries attracted attention to the waste of human life incident +to the mining of fuel and its preparation for the market, with the +result that, in May, 1908, provision was made by Congress for +investigations into the causes of mine explosions with a view to their +prevention. + +Statistics collected by the Geological Survey show that the average +death rate in the coal mines of the United States from accidents of all +kinds, including gas and dust explosions, falls of roof, powder +explosions, etc., is three times that of France, Belgium, or Germany. On +the other hand, in no country in the world are natural conditions so +favorable for the safe extraction of coal as in the United States. In +Belgium, foremost in the study of mining conditions, a constant +reduction in the death rate has been secured, and from a rate once +nearly as great as that of the United States, namely, 3.28 per thousand, +in the period 1851-60, it had been reduced to about 2 per thousand in +the period 1881-90; and in the last decade this has been further reduced +to nearly 1 per thousand. It seems certain, from the investigations +already made by the Geological Survey, that better means of safeguarding +the lives of miners will be found, and that the death rate from mine +accidents will soon show a marked reduction. + +Other statistics collected by the Geological Survey show that, to the +close of 1907, nearly 7,000,000,000 tons of coal had been mined in the +United States, and it is estimated that for every ton mined nearly a ton +has been wasted, 3,500,000,000 tons being left in the ground or thrown +on the dump as of a grade too low for commercial use. To the close of +1907 the production represents an exhaustion of somewhat more than +10,000,000,000 tons of coal. It has been estimated that if the +production continues to increase, from the present annual output of +approximately 415,000,000 tons, at the rate which has prevailed during +the last fifty years, the greater part of the more accessible coal +supply will be exhausted before the middle of the next century. + +The Forest Service estimates that, at the present rate of consumption, +renewals of growth not being taken into account, the timber supply will +be exhausted within the next quarter of a century. It is desirable, +therefore, that all information possible be gained regarding the most +suitable substitutes for wood for building and engineering construction, +such as iron, stone, clay products, concrete, etc., and that the minimum +proportion in which these materials should be used for a given purpose, +be ascertained. Exhaustion, by use in engineering and building +construction, applies not only to the iron ore, clay, and cement-making +materials, but, in larger ratio, to the fuel essential to rendering +these substances available for materials of construction. Incidentally, +investigations into the waste of structural materials have developed the +fact that the destructive losses, due to fires in combustible buildings, +amount to more than $200,000,000 per annum. A sum even greater than this +is annually expended on fire protection. Inquiries looking to the +reduction of fire losses are being conducted in order to ascertain the +most suitable fire-resisting materials for building construction. + +Early in 1904, during the Louisiana Purchase Exposition, Congress made +provision for tests, demonstrations, and investigations concerning the +fuels and structural materials of the United States. These +investigations were organized subsequently as the Technologic Branch of +the United States Geological Survey, under Mr. Joseph A. Holmes, Expert +in Charge, and the President of the United States invited a group of +civilian engineers and Chiefs of Engineering Bureaus of the Government +to act as a National Advisory Board concerning the method of conducting +this work, with a view to making it of more immediate benefit to the +Government and to the people of the United States. This Society is +formally represented on this Board by C. C. Schneider, Past-President, +Am. Soc. C. E., and George S. Webster, M. Am. Soc. C. E. Among +representatives of other engineering societies, or of Government +Bureaus, the membership of the National Advisory Board includes other +members of this Society, as follows: General William Crozier, Frank T. +Chambers, Professor W. K. Hatt, Richard L. Humphrey, Robert W. Hunt, H. +G. Kelley, Robert W. Lesley, John B. Lober, Hunter McDonald, and +Frederick H. Newell. + +In view, therefore, of the important part taken both officially and +unofficially by members of this Society in the planning and organization +of this work, it seems proper to present a statement of the scope, +methods, and progress of these investigations. Whereas the Act governing +this work limits the testing and investigation of fuels and of +structural materials to those belonging to the United States, the +activities of the Federal Government in the use of these materials so +far exceeds that of any other single concern in the United States, that +the results cannot but be of great value to all engineers and to all +those engaged in engineering works. + + +MINE ACCIDENTS INVESTIGATIONS. + +_Organization, and Character of the Work._--The mine rescue +investigations, carried on at the Federal testing station, at Pittsburg, +Pa., include five lines of attack: + +1.--Investigations in the mines to determine the conditions leading up +to mine disasters, the presence and the relative explosibility of mine +gas and coal dust, and mine fires and means of preventing and combating +them. + +2.--Tests to determine the relative safety, or otherwise, of the various +explosives used in coal mining, when ignited in the presence of +explosible mixtures of natural gas and air, or coal dust, or of both. + +3.--Tests to determine the conditions under which electric equipment is +safe in coal-mining operations. + +4.--Tests to determine the safety of various types of mine lights in the +presence of inflammable gas, and their accuracy in detecting small +percentages of mine gas. + +5.--Tests of the various artificial breathing apparatus, and the +training of miners and of skilled mining engineers in rescue methods. + +The first four of these lines of investigation have to do with +preventive measures, and are those on which ultimately the greatest +dependence must be placed. The fifth is one in which the result seems at +first to be the most apparent. It has to do, not with prevention, but +with the cure of conditions which should not arise, or, at least, should +be greatly ameliorated. + +During the last 19 years, 28,514 men have been killed in the coal-mining +industries.[2] In 1907 alone, 3,125 men lost their lives in coal mines, +and, in addition, nearly 800 were killed in the metal mines and quarries +of the country. Including the injured, 8,441 men suffered casualties in +the mines in that year. In every mining camp containing 1,000 men, 4.86 +were taken by violent death in that year. In the mining of coal in Great +Britain, 1.31 men were killed in every 1,000 employed in the same year; +in France, 1.1; in Belgium, 0.94, or less than 1 man in every 1,000 +employed. It is thus seen that from three to four times as many men are +being killed in the United States as in any European coal-producing +country. This safer condition in Europe has resulted from the use of +safer explosives, or the better use of the explosives available; from +the reduction in the use of open lights; from the establishment of mine +rescue stations and the training with artificial breathing apparatus; +and from the adoption of regulations for safeguarding the lives of the +workmen. + +The mining engineering field force of the Geological Survey, at the head +of which is Mr. George S. Rice, an experienced mining and consulting +engineer, has already made great progress in the study of underground +mining conditions and methods. Nearly all the more dangerous coal mines +in the United States have been examined; samples of gas, coal, and dust +have been taken and analyzed at the chemical laboratories at Pittsburg; +extended tests have been made as to the explosibility of various +mixtures of gas and air; as to the explosibility of dust from various +typical coals; as to the chemical composition and physical +characteristics of this dust; the degree of fineness necessary to the +most explosive conditions; and the methods of dampening the dust by +water, by humidifying, by steam, or of deadening its explosibility by +the addition of calcium chloride, stone dust, etc. A bulletin outlining +the results thus far obtained in the study of the coal-dust problem is +now in course of publication.[3] + +After reviewing the history of observations and experiments with coal +dust carried on in Europe, and later, the experiments at the French, +German, Belgian, and English explosives-testing stations, this bulletin +takes up the coal-dust question in the United States. Further chapters +concern the tests as to the explosibility of coal dust, made by the +Geological Survey, at Pittsburg; investigations, both at the Pittsburg +laboratory and in mines, as to the humidity of mine air. There is also a +chapter on the chemical investigations into the ignition of coal dust by +Dr. J. C. W. Frazer, of the Geological Survey. The application of some +of these data to actual mine conditions in Europe, in the last year, is +treated by Mr. Axel Larsen; the use of exhaust steam in a mine of the +Consolidation Coal Company, in West Virginia, is discussed by Mr. Frank +Haas, Consulting Engineer; and the use of sprays in Oklahoma coal mines +is the subject of a chapter by Mr. Carl Scholz, Vice-President of the +Rock Island Coal Mining Company. + +An earlier bulletin setting forth the literature and certain mine +investigations of explosive gases and dust,[4] has already been issued. +After treating of methods of collecting and analyzing the gases found in +mines, of investigations as to the rate of liberation of gas from coal, +and of studies on coal dust, this bulletin discusses such factors as the +restraining influence of shale dust and dampness on coal-dust +explosions. It then takes up practical considerations as to the danger +of explosions, including the relative inflammability of old and fresh +coal dust. The problems involved are undergoing further investigation +and elaboration, in the light of information already gathered. + +_Permissible Explosives._--The most important progress in these tests +and investigations has been made in those relating to the various +explosives used in getting coal from mines. Immediately upon the +enactment of the first legislation, in the spring of 1908, arrangements +were perfected whereby the lower portion of the old Arsenal grounds +belonging to the War Department and adjacent to the Pennsylvania +Railroad, on the Alleghany River, at 40th and Butler Streets, Pittsburg, +Pa., were transferred to the Interior Department for use in these +investigations. Meantime, in anticipation of the appropriation, Mr. +Clarence Hall, an engineer experienced in the manufacture and use of +explosives, was sent to Europe to study the methods of testing +explosives practiced at the Government stations in Great Britain, +Germany, Belgium, and France. Mr. Joseph A. Holmes also visited Europe +for the purpose of studying methods of ameliorating conditions in the +mines. Three foreign mining experts, the chiefs of investigating bureaus +in Belgium, Germany, and England, spent three months studying conditions +in the United States at the invitation of the Secretary of the Interior, +to whom they submitted a valuable report.[5] + +Under the supervision of the writer, Chief Engineer of these +investigations, detailed plans and specifications had been prepared in +advance for the necessary apparatus and the transformation of the +buildings at Pittsburg to the purposes of this work. It was possible, +therefore, to undertake immediately the changes in existing buildings, +the erection of new buildings, the installation of railway tracks, +laboratories, and the plumbing, heating, and lighting plant, etc. This +work was carried on with unusual expedition, under the direction of the +Assistant Chief Engineer, Mr. James C. Roberts, and was completed within +a few months, by which time most of the apparatus was delivered and +installed. + +One building (No. 17) is devoted to the smaller physical tests of +explosives. It was rendered fire resistant by heavily covering the +floors, ceiling, and walls with cement on metal lath, and otherwise +protecting the openings. In it are installed apparatus for determining +calorific value of explosives, pressure produced on ignition, +susceptibility to ignition when dropped, rate of detonation, length and +duration of flame, and kindred factors. Elsewhere on the grounds is a +gallery of boiler-steel plate, 100 ft. long and more than 6 ft. in +diameter, solidly attached to a mass of concrete at one end, in which is +embedded a cannon from which to discharge the explosive under test, and +open at the other end, and otherwise so constructed as to simulate a +small section of a mine gallery (Fig. 2, Plate VI). The heavy mortar +pendulum, for the pendulum test for determining the force produced by an +explosive, is near by, as is also an armored pit in which large +quantities of explosive may be detonated, with a view to studying the +effects of magazine explosions, and for testing as to the rate at which +ignition of an explosive travels from one end to the other of a +cartridge, and the sensitiveness of one cartridge to explosion by +discharge of another near by. + + [Illustration: PLATE VI. + + Fig. 1.--Explosion from Coal Dust in Gas and Dust Gallery No. 1. + + Fig. 2.--Mine Gallery No. 1. + + Fig. 3.--Ballistic Pendulum.] + +In another building (No. 21), is a well-equipped chemical laboratory for +chemical analyses and investigations of explosives, structural +materials, and fuels. + +Several months were required to calibrate the various apparatus, and to +make analyses of the available natural gas to determine the correct +method of proportioning it with air, so as to produce exact mixtures of +2, 4, 6, or 8% of methane with air. Tests of existing explosives were +made in air and in inflammable mixtures of air and gas, with a view to +fixing on some standard explosive as a basis of comparison. Ultimately, +40% nitro-glycerine dynamite was adopted as the standard. Investigative +tests having been made, and the various factors concerning all the +explosives on the market having been determined, a circular was sent to +all manufacturers of explosives in the United States, on January 9th, +1909, and was also published in the various technical journals, through +the associated press, and otherwise. + +On May 15th, 1909, all the explosives which had been offered for test, +as permissible, having been tested, the first list of permissible +explosives was issued, as given in the following circular: + + “EXPLOSIVES CIRCULAR NO. 1. + “DEPARTMENT OF THE INTERIOR. + “United States Geological Survey. + “May 15, 1909. + + “LIST OF PERMISSIBLE EXPLOSIVES. + “Tested prior to May 15, 1909. + + “As a part of the investigation of mine explosions authorized by + Congress in May, 1908, it was decided by the Secretary of the Interior + that a careful examination should be made of the various explosives + used in mining operations, with a view to determining the extent to + which the use of such explosives might be responsible for the + occurrence of these disasters. + + “The preliminary investigation showed the necessity of subjecting to + rigid tests all explosives intended for use in mines where either gas + or dry inflammable dust is present in quantity or under conditions + which are indicative of danger. + + “With this in view, a letter was sent by the Director of the United + States Geological Survey on January 9, 1909, to the manufacturers of + explosives in the United States, setting forth the conditions under + which these explosives would be examined and the nature of the tests + to which they would be subjected. + + “Inasmuch as the conditions and tests described in this letter were + subsequently followed in testing the explosives given in the list + below, they are here reproduced, as follows: + + “(1) The manufacturer is to furnish 100 pounds of each explosive which + he desires to have tested; he is to be responsible for the care, + handling, and delivery of this material at the testing station on the + United States arsenal grounds, Fortieth and Butler streets, Pittsburg, + Pa., at the time the explosive is to be tested; and he is to have a + representative present during the tests, who will be responsible for + the handling of the packages containing the explosives until they are + opened for testing. + + “(2) No one is to be present at or to participate in these tests + except the necessary government officers at the testing station, their + assistants, and the representative of the manufacturer of the + explosives to be tested. + + “(3) The tests will be made in the order of the receipt of the + applications for them, provided the necessary quantity of the + explosive is delivered at the plant by the time assigned, of which due + notice will be given by the Geological Survey. + + “(4) Preference will be given to the testing of explosives that are + now being manufactured and that are in that sense already on the + market. No test will be made of any new explosive which is not now + being manufactured and marketed, until all explosives now on the + market that may be offered for testing have been tested. + + “(5) A list of the explosives which pass certain requirements + satisfactorily will be furnished to the state mine inspectors, and + will be made public in such further manner as may be considered + desirable. + + “TEST REQUIREMENTS FOR EXPLOSIVES. + + “The tests will be made by the engineers of the United States + Explosives Testing Station at Pittsburg, Pa., in gas and dust gallery + No. 1. The charge of explosive to be fired in tests 1, 2, and 3 shall + be equal in disruptive power to one-half pound (227 grams) of 40 per + cent. nitroglycerin dynamite in its original wrapper, of the following + formula: + + Nitroglycerin 40 + Nitrate of sodium 44 + Wood pulp 15 + Calcium carbonate 1 + --- + 100 + + “Each charge shall be fired with an electric fuse of sufficient power + to completely detonate or explode the charge, as recommended by the + manufacturer. The explosive must be in such condition that the + chemical and physical tests do not show any unfavorable results. The + explosives in which the charge used is less than 100 grams (0.22 + pound) will be weighed in tinfoil without the original wrapper. + + “The dust used in tests 2, 3, and 4 will be of the same degree of + fineness and taken from one mine.[6] + + [Footnote 6: With a view to obtaining a dust of uniform purity and + inflammability.] + + “TEST 1.--Ten shots with the charge as described above, in its + original wrapper, shall be fired, each with 1 pound of clay tamping, + at a gallery temperature of 77° F., into a mixture of gas and air + containing 8 per cent. of methane and ethane. An explosive will pass + this test if all ten shots fail to ignite the mixture. + + “TEST 2.--Ten shots with charge as previously noted, in its original + wrapper, shall be fired, each with 1 pound of clay tamping at a + gallery temperature of 77° F., into a mixture of gas and air + containing 4 per cent. of methane and ethane and 20 pounds of + bituminous coal dust, 18 pounds of which is to be placed on shelves + laterally arranged along the first 20 feet of the gallery, and 2 + pounds to be placed near the inlet of the mixing system in such a + manner that all or part of it will be suspended in the first division + of the gallery. An explosive will pass this test if all ten shots fail + to ignite the mixture. + + “TEST 3.--Ten shots with charge as previously noted, in its original + wrapper, shall be fired, each with 1 pound of clay tamping at a + gallery temperature of 77° F., into 40 pounds of bituminous coal dust, + 20 pounds of which is to be distributed uniformly on a horse placed in + front of the cannon and 20 pounds placed on side shelves in sections + 4, 5, and 6. An explosive will pass this test if all ten shots fail to + ignite the mixture. + + “TEST 4.--A limit charge will be determined within 25 grams by firing + charges in their original wrappers, untamped, at a gallery temperature + of 77° F., into a mixture of gas and air containing 4 per cent. of + methane and ethane and 20 pounds of bituminous coal dust, to be + arranged in the same manner as in test 2. This limit charge is to be + repeated five times under the same conditions before being + established. + + “NOTE.--At least 2 pounds of clay tamping will be used with + slow-burning explosives. + + “Washington, D.C., _January 9, 1909_. + + “In response to the above communication applications were received + from 12 manufacturers for the testing of 29 explosives. Of these + explosives, the 17 given in the following list have passed all the + test requirements set forth, and will be termed permissible + explosives. + + “_Permissible explosives tested prior to May 15, 1909._ + + ----------------------------+---------------------------------------- + Brand. | Manufacturer. + ----------------------------+---------------------------------------- + Ætna coal powder A | Ætna Powder Co., Chicago, Ill. + Ætna coal powder B | Do. + Carbonite No. 1 | E. I. Dupont de Nemours Powder Co., + | Wilmington, Del. + Carbonite No. 2 | E. I. Du Pont de Nemours Powder Co., + | Wilmington, Del. + Carbonite No. 3 | Do. + Carbonite No. 1 L. F. | Do. + Carbonite No. 2 L. F. | Do. + Coal special No. 1 | Keystone Powder Co., Emporium, Pa. + Coal special No. 2 | Do. + Coalite No. 1 | Potts Powder Co., New York City. + Coalite No. 2 D | Do. + Collier dynamite No. 2 | Sinnamahoning Powder Co., Emporium, Pa. + Collier dynamite No. 4 | Do. + Collier dynamite No. 5 | Do. + Masurite M. L. F. | Masurite Explosive Co., Sharon, Pa. + Meteor dynamite | E. I. Du Pont de Nemours Powder Co., + | Wilmington, Del. + Monobel | Do. + ----------------------------+---------------------------------------- + + “Subject to the conditions named below, a permissible explosive is + defined as an explosive which has passed gas and dust gallery tests + Nos. 1, 2, and 3 as described above, and of which in test No. 4 1½ + pounds (680 grams) of the explosive has been fired into the mixture + there described without causing an ignition. + + “_Provided:_ + + “1. That the explosive is in all respects similar to the sample + submitted by the manufacturer for test. + + “2. That double-strength detonators are used of not less strength than + 1 gram charge consisting by weight of 90 parts of mercury fulminate + and 10 parts of potassium chlorate (or its equivalent), except for the + explosive ‘Masurite M. L. F.’ for which the detonator shall be of not + less strength than 1½ grams charge. + + “3. That the explosive, if in a frozen condition, shall be thoroughly + thawed in a safe and suitable manner before use. + + “4. That the amount used in practice does not exceed 1½ pounds (680 + grams) properly tamped. + + “The above partial list includes the permissible explosives that have + passed these tests prior to May 15, 1909. The announcement of the + passing of like tests by other explosives will be made public + immediately after the completion of the tests for such explosives. + + “A description of the method followed in making these and the many + additional tests to which each explosive is subjected, together with + the full data obtained in each case, will be published by the Survey + at an early date. + + “NOTES AND SUGGESTIONS. + + “It may be wise to point out in this connection certain differences + between the permissible explosives as a class and the black powders + now so generally used in coal mining, as follows: + + “(_a_) With equal quantities of each, the flame of the black powder is + more than three times as long and has a duration three thousand to + more than four thousand times that of one of the permissible + explosives, also the rate of explosion is slower. + + “(_b_) The permissible explosives are one and one-fourth to one and + three-fourths times as strong and are said, if properly used, to do + twice the work of black powder in bringing down coal; hence only half + the quantity need be used. + + “(_c_) With 1 pound of a permissible explosive or 2 pounds of black + powder, the quantity of noxious gases given off from a shot averages + approximately the same, the quantity from the black powder being less + than from some of the permissible explosives and slightly greater than + from others. The time elapsing after firing before the miner returns + to the working face or fires another shot should not be less for + permissible explosives than for black powder. + + “The use of permissible explosives should be considered as + supplemental to and not as a substitute for other safety precautions + in mines where gas or inflammable coal dust is present under + conditions indicative of danger. As stated above, they should be used + with strong detonators; and the charge used in practice should not + exceed 1½ pounds, and in many cases need not exceed 1 pound. + + “Inasmuch as no explosive manufactured for use in mining is flameless, + and as no such explosive is entirely safe under all the variable + mining conditions, the use of the terms ‘flameless’ and ‘safety’ as + applied to explosives is likely to be misunderstood, may endanger + human life, and should be discouraged. + + “JOSEPH A. HOLMES, + “_Expert in Charge Technologic Branch_. + + “Approved, May 18, 1909: + “GEO. OTIS SMITH, + “_Director_.” + +In the meantime, many of the explosives submitted, which heretofore had +been on the market as safety explosives, were found to be unsafe for +use in gaseous or dusty mines, and the manufacturers were permitted +to withdraw them. Their weaknesses being known, as a result of these +tests, the manufacturers were enabled to produce similar, but safer, +explosives. Consequently, applications for further tests continued +to pour in, as they still do, and on October 1st, 1909, a second list +of permissible explosives was issued, as follows: + + “EXPLOSIVES CIRCULAR NO. 2. + “DEPARTMENT OF THE INTERIOR. + “United States Geological Survey. + “October 1, 1909. + + “LIST OF PERMISSIBLE EXPLOSIVES. + “Tested prior to October 1, 1909. + + “The following list of permissible explosives tested by the United + States Geological Survey at Pittsburg, Pa., is hereby published for + the benefit of operators, mine owners, mine inspectors, miners, and + others interested. + + “The conditions and test requirements described in Explosives Circular + No. 1, issued under date of May 15, 1909, have been followed in all + subsequent tests. + + “Subject to the provisions named below, a permissible explosive is + defined as an explosive which is in such condition that the chemical + and physical tests do not show any unfavorable results; which has + passed gas and dust gallery tests Nos. 1 and 3, as described in + circular No. 1; and of which, in test No. 4, 1½ pounds (680 grams) has + been fired into the mixture there described without causing ignition. + + “_Permissible explosives tested prior to October 1, 1909._ + + “[Those reported in Explosives Circular No. 1 are marked *.] + + ------------------------------+------------------------------------- + Brand. | Manufacturer. + ------------------------------+------------------------------------- + *Ætna coal powder A | Ætna Powder Co., Chicago, Ill. + Ætna coal powder AA | Do. + *Ætna coal powder B | Do. + Ætna coal powder C | Do. + Bituminite No. 1 | Jefferson Powder Co., Birmingham, + | Ala. + Black Diamond No. 3 | Illinois Powder Manufacturing Co., + | St. Louis, Mo. + Black Diamond No. 4 | Do. + *Carbonite No. 1 | E. I. Du Pont de Nemours Powder Co., + | Wilmington, Del. + *Carbonite No. 2 | Do. + *Carbonite No. 3 | Do. + *Carbonite No. 1-L. F. | Do. + *Carbonite No. 2-L. F. | Do. + *Coalite No. 1 | Potts Powder Co., New York City. + *Coalite No. 2-D. | Do. + *Coal special No. 1 | Keystone Powder Co., Emporium, Pa. + *Coal special No. 2 | Do. + *Collier dynamite No. 2. | Sinnamahoning Powder Manufacturing + | Co., Emporium, Pa. + *Collier dynamite No. 4. | Do. + *Collier dynamite No. 5. | Do. + Giant A low-flame dynamite. | Giant Powder Co. (Con.), Giant, Cal. + Giant B low-flame dynamite. | Do. + Giant C low-flame dynamite. | Do. + *Masurite M. L. F. | Masurite Explosives Co., Sharon, Pa. + *Meteor dynamite. | E. I. Du Pont de Nemours Powder Co., + | Wilmington, Del. + Mine-ite A. | Burton Powder Co., Pittsburg, Pa. + Mine-ite B. | Do. + *Monobel. | E. I. Du Pont de Nemours Powder Co., + | Wilmington, Del. + Tunnelite No. 5. | G. R. McAbee Powder and Oil Co., + | Pittsburg, Pa. + Tunnelite No. 6. | Do. + Tunnelite No. 7. | Do. + Tunnelite No. 8. | Do. + ------------------------------+------------------------------------- + + “_Provided:_ + + “1. That the explosive is in all respects similar to sample submitted + by the manufacturer for test. + + “2. That No. 6 detonators, preferably No. 6 electric detonators + (double strength), are used of not less strength than 1 gram charge, + consisting by weight of 90 parts of mercury fulminate and 10 parts of + potassium chlorate (or its equivalent), except for the explosive + ’Masurite M. L. F.,’ for which the detonator shall be of not less + strength than 1½ grams charge. + + “3. That the explosive, if frozen, shall be thoroughly thawed in a + safe and suitable manner before use. + + “4. That the amount used in practice does not exceed 1½ pounds (680 + grams), properly tamped. + + “The above partial list includes all the permissible explosives that + have passed these tests prior to October 1, 1909. The announcement of + the passing of like tests by other explosives will be made public + immediately after the completion of the tests. + + “With a view to the wise use of these explosives it may be well in + this connection to point out again certain differences between the + permissible explosives as a class and the black powders now so + generally used in coal mining, as follows: + + “(_a_) With equal quantities of each, the flame of the black powder is + more than three times as long and has a duration three thousand to + more than four thousand times that of one of the permissible + explosives; the rate of explosion also is slower. + + “(_b_) The permissible explosives are one and one-fourth to one and + three-fourths times as strong and are said, if properly used, to do + twice the work of black powder in bringing down coal; hence only half + the quantity need be used. + + “(_c_) With 1 pound of a permissible explosive or 2 pounds of black + powder, the quantity of noxious gases given off from a shot averages + approximately the same, the quantity from the black powder being less + than from some of the permissible explosives and slightly greater than + from others. The time elapsing after firing before the miner returns + to the working face or fires another shot should not be less for + permissible explosives than for black powder. + + “The use of permissible explosives should be considered as + supplemental to and not as a substitute for other safety precautions + in mines where gas or inflammable coal dust is present under + conditions indicating danger. As stated above, they should be used + with strong detonators, and the charge used in practice should not + exceed 1½ pounds and in many cases need not exceed 1 pound. + + “JOSEPH A. HOLMES, + “_Expert in Charge Technologic Branch._ + “Approved, October 11, 1909. + “H. C. RIZER, + “_Acting Director._” + +The second list contains 31 explosives which the Government is prepared +to brand as permissible, and therefore comparatively safe, for use in +gaseous and dusty mines. An equally large number of so-called safety +powders failed to pass these tests. Immediately on the passing of the +tests, as to the permissibility of any explosive, the facts are reported +to the manufacturer and to the various State mine inspectors. When +published, the permissible lists were issued to all explosives +manufacturers, all mine operators in the United States, and State +inspectors. The effect has been the enactment, by three of the largest +coal-producing States, of legislation or regulations prohibiting the use +of any but permissible explosives in gaseous or dusty mines, and other +States must soon follow. To prevent fraud, endeavor is being made to +restrict the use of the brand “Permissible Explosive, U.S. Testing +Station, Pittsburg, Pa.,” to only such boxes or packages as contain +listed permissible explosives. + +As these tests clearly demonstrate, both in the records thereof and +visually to such as follow them, that certain explosives, especially +those which are slow-burning like black powder, or produce high +temperature in connection with comparative slow burning, will ignite +mixtures of gas and air, or mixtures of coal dust and air, and cause +explosions. The results point out clearly to all concerned, the danger +of using such explosives. The remedy is also made available by the +announcement of the names of a large number of explosives now on the +market at reasonable cost, which will not cause explosions under these +conditions. It is believed that when permissible explosives are +generally adopted in coal mines, this source of danger will have been +greatly minimized. + +_Explosives Investigations._--Questions have arisen on the part of +miners or of mine operators as to the greater cost in using permissible +explosives due to their expense, which is slightly in excess of that of +other explosives; as to their greater shattering effect in breaking down +the coal, and in giving a smaller percentage of lump and a larger +percentage of slack; and as to the possible danger of breathing the +gases produced. + +Observations made in mines by Mr. J. J. Rutledge, an experienced coal +miner and careful mining engineer connected with the Geological Survey, +as to the amount of coal obtained by the use of permissible and other +explosives, tend to indicate that the permissible explosives are not +more, but perhaps less expensive than others, in view of the fact that, +because of their greater relative power, a smaller quantity is required +to do the work than is the case, say, with black powder. On the other +hand, for safety and for certainty of detonation, stronger detonators +are recommended for use with permissible explosives, preferably electric +detonators. These may cost a few cents more per blast than the squib or +fuse, but there is no danger that they will ignite the gas, and the +difference in cost is, in some measure, offset by the greater certainty +of action and the fact that they produce a much more powerful explosion, +thus again permitting the use of still smaller quantities of the +explosive and, consequently, reducing the cost. These investigations are +still in progress. + +Concerning the shattering of the coal: This is being remedied in some of +the permissible explosives by the introduction of dopes, moisture, or +other means of slowing down the disruptive effect, so as to produce the +heaving and breaking effect obtained with the slower-burning powders +instead of the shattering effect produced by dynamite. There is every +reason to believe that as the permissible explosives are perfected, and +as experience develops the proper methods of using them, this difficulty +will be overcome in large measure. This matter is also being +investigated by the Survey mining engineers and others, by the actual +use of such explosives in coal-mining operations. + +Of the gases given off by explosives, those resulting from black powder +are accompanied by considerable odor and smoke, and, consequently, the +miners go back more slowly after the shots, allowing time for the gases +to be dissipated by the ventilation. With the permissible explosive, the +miner, seeing no smoke and observing little odor, is apt to be +incautious, and to think that he may run back immediately. As more is +learned of the use of these explosives, this source of danger, which is, +however, inconsiderable, will be diminished. Table 1 gives the +percentages of the gaseous products of combustions from equal weights of +black powder and two of the permissible explosives. Of the latter, one +represents the maximum amount of injurious gases, and the other the +minimum amount, between which limits the permissible explosives +approximately vary. + +Such noxious gases as may be produced by the discharge of the explosive +are diluted by a much larger volume of air, and are practically +harmless, as proven by actual analysis of samples taken at the face +immediately after a discharge. + + TABLE 1. + + --------+---------+-------------------------- + | | Permissible Explosives. + | Black |-------------+------------ + | powder. | Maximum. | Minimum. + --------+---------+-------------+------------ + CO_{2} | 22.8 | 14.50 | 21.4 + CO | 10.3 | 27.74 | 1.3 + N | 10.3 | 45.09 | 74.4 + --------+---------+-------------+------------ + +In addition to investigations as to explosives for use in coal mining, +the Explosives Section of the Geological Survey analyzes and tests all +such materials, fuses, caps, etc., purchased by the Isthmian Canal +Commission, as well as many other kinds used by the Government. It is +thus acquiring a large fund of useful information, which will be +published from time to time, relative to the kinds of explosives and the +manner of using them best suited to any blasting operations, either +above or under water, in hard rock, earth, or coal. There has been +issued from the press, recently, a primer of explosives,[7] by Mr. +Clarence Hall, the engineer in charge of these tests, and Professor C. +E. Munroe, Consulting Explosives Chemist, which contains a large amount +of valuable fundamental information, so simply expressed as to be easily +understandable by coal miners, and yet sufficiently detailed to be a +valuable guide to all persons who have to handle or use explosives. + +In the first chapters are described the various combustible substances, +and the chemical reactions leading to their explosibility. The low and +high explosives are differentiated, and the sensitiveness of fulminate +of mercury and other detonators is clearly pointed out. The various +explosives, such as gunpowder, black blasting powder, potassium chlorate +powders, nitro-glycerine powders, etc., are described, and their +peculiarities and suitability for different purposes are set forth. The +character and method of using the different explosives, both in opening +up work and in enclosed work in coal mines, follow, with information as +to the proper method of handling, transporting, storing, and thawing the +same. Then follow chapters on squibs, fuses, and detonators; on methods +of shooting coal off the solid; location of bore-holes; undercutting; +and the relative advantages of small and large charges, with +descriptions of proper methods of loading and firing the same. The +subjects of explosives for blasting in rock, firing machines, blasting +machines, and tests thereof, conclude the report. + +The work of the chemical laboratory in which explosives are analyzed, +and in which mine gases and the gases produced by combustion of +explosives and explosions of coal-gas or coal dust are studied, has been +of the most fundamental and important character. The Government is +procuring a confidential record of the chemical composition and mode of +manufacture of all explosives, fuses, etc., which are on the market. +This information cannot but add greatly to the knowledge as to the +chemistry of explosives for use in mines, and will furnish the basis on +which remedial measures may be devised. + +A bulletin (shortly to go to press) which gives the details of the +physical tests of the permissible explosives thus far tested, will set +forth elaborately the character of the testing apparatus, and the method +of use and of computing results.[8] + +This bulletin contains a chapter, by Mr. Rutledge, setting forth in +detail the results of his observations as to the best methods of using +permissible explosives in getting coal from various mines in which they +are used. This information will be most valuable in guiding mining +engineers who desire to adopt the use of permissible explosives, as to +the best methods of handling them. + +_Electricity in Mines._--In connection with the use of electricity in +mines, an informal series of tests has been made on all enclosed +electric fuses, as to whether or not they will ignite an explosive +mixture of air and gas when blown out. The results of this work, which +is under the direction of Mr. H. H. Clark, Electrical Engineer for +Mines, have been furnished the manufacturers for their guidance in +perfecting safer fuses, a series of tests of which has been announced. A +series of tests as to the ability of the insulation of electric wiring +to withstand the attacks of acid mine waters is in progress, which will +lead, it is hoped, to the development of more permanent and cheaper +insulation for use in mine wiring. A series of competitive tests of +enclosed motors for use in mines has been announced, and is in progress, +the object being to determine whether or not sparking from such motors +will cause an explosion in the presence of inflammable gas. + +In the grounds outside of Building No. 10 is a large steel gallery, much +shorter than Gallery No. 1, in fact, but 30 ft. in length, and much +greater in diameter, namely, 10 ft. (Fig. 3, Plate X), in which electric +motors, electric cutting machines, and similar apparatus, are being +tested in the presence of explosive mixtures of gas and dust and with +large amperage and high voltage, such as may be used in the largest +electrical equipment in mines. + +The investigation as to the ability of insulation to withstand the +effects of acid mine waters has been very difficult and complicated. At +first it was believed possible that mine waters from nearby Pennsylvania +mines and of known percentages of acidity could be procured and kept in +an immersion tank at approximately any given percentage of strength. +This was found to be impracticable, as these waters seem to undergo +rapid change the moment they are exposed to the air or are transported, +in addition to the changes wrought by evaporation in the tank. It has +been necessary, therefore, to analyze and study carefully these waters +with a view to reproducing them artificially for the purpose of these +tests. Concerning the insulation, delicate questions have arisen as to a +standard of durability which shall be commensurate with reasonable cost. +These preliminary points are being solved in conference with the +manufacturers, and it is expected that the results will soon permit of +starting the actual tests. + +_Safety-Lamp Investigations._--Many so-called safety lamps are on the +market, and preliminary tests of them have been made in the lamp +gallery, in Building No. 17 (Fig. 2, Plate X). After nearly a year of +endeavor to calibrate this gallery, and to co-ordinate its results with +those produced in similar galleries in Europe, this preliminary inquiry +has been completed, and the manufacturers and agents of all safety lamps +have been invited to be present at tests of their products at the +Pittsburg laboratory. + +A circular dated November 19th, 1909, contains an outline of these +tests, which are to be conducted under the direction of Mr. J. W. Paul, +an experienced coal-mining engineer and ex-Chief of the Department of +State Mine Inspection of West Virginia. The lamps will be subjected to +the following tests: + +(_a_).--Each lamp will be placed in a mixture of air and explosive +natural gas containing 6, 8, and 10% of gas, moving at a velocity of +from 200 to 2,500 ft. per min., to determine the velocity of the air +current which will ignite the mixture surrounding the lamp. The current +will be made to move against the lamp in a horizontal, vertical +ascending, and vertical descending direction, and at an angle of 45°, +ascending and descending. + +(_b_).--After completing the tests herein described, the lamps will be +subjected to the tests described under (_a_), with the air and gas +mixture under pressure up to 6 in. of water column. + +(_c_).--Under the conditions outlined in (_a_), coal dust will be +introduced into the current of air and gas to determine its effect, if +any, in inducing the ignition of the gas mixture. + +(_d_).--Each lamp will be placed in a mixture of air and varying +percentages of explosive natural gas to determine the action of the gas +on the flame of the lamp. + +(_e_).--Each lamp will be placed in a mixture of air and varying +percentages of carbonic acid gas to determine the action of the gas on +the flame. + +(_f_).--Lamps equipped with internal igniters will be placed in +explosive mixtures of air and gas in a quiet state and in a moving +current, and the effect of the igniter on the surrounding mixture will +be observed. + +(_g_).--The oils (illuminants) used in the lamps will be tested as to +viscosity, gravity, flashing point, congealing point, and composition. + +(_h_).--Safety-lamp globes will be tested by placing each globe in +position in the lamp and allowing the flame to impinge against the globe +for 3 min. after the lamp has been burning with a full flame for 10 +min., to determine whether the globe will break. + +(_i_).--Each safety-lamp globe will be mounted in a lighted lamp with +up-feed, and placed for 5 min. in an explosive mixture of air and gas +moving at the rate of 1,000 ft. per min., to determine whether the heat +will break the glass and, if it is broken, to note the character of the +fracture. + +(_j_).--Safety-lamp globes will be broken by impact, by allowing each +globe to fall and strike, horizontally, on a block of seasoned white +oak, the distance of fall being recorded. + +(_k_).--Each safety lamp globe will be mounted in a safety lamp and, +when the lamp is in a horizontal position, a steel pick weighing 100 +grammes will be permitted to fall a sufficient distance to break the +globe by striking its center, the distance of the fall to be recorded. + +(_l_).--To determine the candle power of safety lamps, a photometer +equipped with a standardized lamp will be used. The candle-power will be +determined along a line at right angles to the axis of the flame; also +along lines at angles to the axis of the flame both above and below the +horizontal. The candle-power will be read after the lamp has been +burning 20 min. + +(_m_).--The time a safety lamp will continue to burn with a full charge +of illuminant will be determined. + +(_n_).--Wicks in lamps must be of sufficient length to be at all times +in contact with the bottom of the vessel in which the illuminant is +contained, and, before it is used, the wick shall be dried to remove +moisture. + +_Mine-Rescue Methods._--Mr. Paul, who has had perhaps as wide an +experience as any mining man in the investigation of and in rescue work +at mine disasters, is also in charge of the mine-rescue apparatus and +training for the Geological Survey. These operations consist chiefly of +a thorough test of the various artificial breathing apparatus, or +so-called oxygen helmets. Most of these are of European make and find +favor in Great Britain, Belgium, France, or Germany, largely according +as they are of domestic design and manufacture. As yet nothing has been +produced in the United States which fulfills all the requirements of a +thoroughly efficient and safe breathing apparatus for use in mine +disasters. + +At the Pittsburg testing station there are a number of all kinds of +apparatus. The tests of these are to determine ease of use, of repair, +durability, safety under all conditions, period during which the supply +of artificial air or oxygen can be relied on, and other essential data. + +In addition to the central testing station, sub-stations for training +miners, and as headquarters for field investigation as to the causes of +mine disasters and for rescue work in the more dangerous coal fields, +have been established; at Urbana, Ill., in charge of Mr. R. Y. Williams, +Mining Engineer; at Knoxville, Tenn., in charge of Mr. J. J. Rutledge, +Mining Engineer; at McAlester, Okla., in charge of Mr. L. M. Jones, +Assistant Mining Engineer; and at Seattle, Wash., in charge of Mr. Hugh +Wolflin, Assistant Mining Engineer. Others may soon be established in +Colorado and elsewhere, in charge of skilled mining engineers who have +been trained in this work at Pittsburg, and who will be assisted by +trained miners. It is not to be expected that under any but +extraordinary circumstances, such as those which occurred at Cherry, +Ill., the few Government engineers, located at widely scattered points +throughout the United States, can hope to save the lives of miners after +a disaster occurs. As a rule, all who are alive in the mine on such an +occasion, are killed within a few hours. This is almost invariably the +case after a dust explosion, and is likely to be true after a gas +explosion, although a fire such as that at Cherry, Ill., offers the +greatest opportunity for subsequent successful rescue operations. The +most to be hoped for from the Government engineers is that they shall +train miners and be available to assist and advise State inspectors and +mine owners, should their services be called for. + +It should be borne in mind that the Federal Government has no police +duties in the States, and that, therefore, its employees may not direct +operations or have other responsible charge in the enforcement of State +laws. There is little reason to doubt that these Federal mining +engineers, both because of their preliminary education as mining +engineers and their subsequent training in charge of mine operations, +and more recently in mine-accidents investigations and rescue work, are +eminently fitted to furnish advice and assistance on such occasions. The +mere fact that, within a year, some of these men have been present at, +and assisted in, rescue work or in opening up after disasters at nearly +twenty of such catastrophes, whereas the average mining engineer or +superintendent may be connected with but one in a lifetime, should make +their advice and assistance of supreme value on such occasions. They +cannot be held in any way responsible for tardiness, however, nor be +unduly credited with effective measures taken after a mine disaster, +because of their lack of responsible authority or charge, except in +occasional instances where such may be given them by the mine owners or +the State officials, from a reliance on their superior equipment for +such work. + +Successful rescue operations may only be looked for when the time, now +believed to be not far distant, has been reached when the mine operators +throughout the various fields will have their own rescue stations, as is +the practice in Europe, and have available, at certain strategic mines, +the necessary artificial breathing apparatus, and have in their employ +skilled miners who have been trained in rescue work at the Government +stations. Then, on the occurrence of a disaster, the engineer in charge +of the Government station may advise by wire all those who have proper +equipment or training to assemble, and it may be possible to gather, +within an hour or two of a disaster, a sufficiently large corps of +helmet-men to enable them to recover such persons as have not been +killed before the fire--which usually is started by the explosion--has +gained sufficient headway to prevent entrance into the mine. Without +such apparatus, it is essential that the fans be started, and the mine +cleared of gas. The usual effect of this is to give life to any +incipient fire. With the apparatus, the more dense the gas, the safer +the helmet-men are from a secondary explosion or from the rapid ignition +of a fire, because of the absence of the oxygen necessary to combustion. + +The miners who were saved at Cherry, Ill., on November 20th, 1909, owe +their lives primarily to the work of the Government engineers. The +sub-station of the Survey at Urbana, Ill., was promptly notified of the +disaster on the afternoon of November 13th. Arrangements were +immediately made, whereby Mr. R. Y. Williams, Mining Engineer in Charge, +and his Assistant, Mr. J. M. Webb, with their apparatus, were rushed by +special train to the scene, arriving early the following day (Sunday). + +Chief Mining Engineer, George S. Rice, Chief of Rescue Division, J. W. +Paul, and Assistant Engineer, F. F. Morris, learned of the disaster +through the daily press, at their homes in Pittsburg, on Sunday. They +left immediately with four sets of rescue apparatus, reaching Cherry on +Monday morning. Meantime, Messrs. Williams and Webb, equipped with +oxygen helmets, had made two trips into the shaft, but were driven out +by the heat. Both shafts were shortly resealed with a view to combating +the fire, which had now made considerable headway. + +The direction of the operations at Cherry, was, by right of +jurisdiction, in charge of the State Mine Inspectors of Illinois, at +whose solicitation the Government engineers were brought into conference +as to the proper means to follow in an effort to get into the mine. The +disaster was not due to an explosion of coal or gas, but was the result +of a fire ignited in hay, in the stable within the mine. The flame had +come through the top of the air-shaft, and had disabled the ventilating +fans. A rescue corps of twelve men, unprotected by artificial breathing +apparatus, had entered the mine, and all had been killed. When the +shafts were resealed on Monday evening, the 15th, a small hole was left +for the insertion of a water-pipe or hose. During the afternoon and +evening, a sprinkler was rigged up, and, by Tuesday morning, was in +successful operation, the temperature in the shaft at that time being +109° Fahr. After the temperature had been reduced to about 100°, the +Federal engineers volunteered to descend into the shaft and make an +exploration. The rescue party, consisting of Messrs. Rice, Paul, and +Williams, equipped with artificial breathing apparatus, made an +exploration near the bottom of the air-shaft and located the first body. +After they had returned to the surface, three of the Illinois State +Inspectors, who had previously received training by the Government +engineers in the use of the rescue apparatus, including Inspectors Moses +and Taylor, descended, made tests of the air, and found that with the +fan running slowly, it was possible to work in the shaft. The rescue +corps then took hose down the main shaft, having first attached it to a +fire engine belonging to the Chicago Fire Department. Water was directed +on the fire at the bottom of the shaft, greatly diminishing its force, +and it was soon subdued sufficiently to permit the firemen to enter the +mine without the protection of breathing apparatus. + +Unfortunately, these operations could be pursued only under the most +disadvantageous circumstances and surrounded by the greatest possible +precautions, due to the frequent heavy falls of roof--a result of the +heating by the mine fire--and the presence of large quantities of +black-damp. All movements of unprotected rescuers had to be preceded by +exploration by the trained rescue corps, who analyzed the gases, as the +fire still continued to burn, and watched closely for falls, possible +explosions, or a revival of the fire. While the heavy work of shoring +up, and removing bodies, was being carried on by the unprotected rescue +force, the helmet-men explored the more distant parts of the mine, and +on Saturday afternoon, November 20th, one week after the disaster, a +room was discovered in which a number of miners, with great presence of +mind, had walled themselves in in order to keep out the smoke and heat. +From this room 20 living men were taken, of whom 12 were recovered in a +helpless condition, by the helmet-men. + +This is not the first time this Government mining corps has performed +valiant services. Directly and indirectly the members have saved from +fifteen to twenty lives in the short time they have been organized. At +the Marianna, Pa., disaster, the corps found one man still alive among +150 bodies, and he was brought to the surface. He recovered entirely +after a month in the hospital. + +At the Leiter mine, at Zeigler, Ill., two employees, who had been +trained in the use of the oxygen helmets by members of the Government’s +corps, went down into the mine, following an explosion, and brought one +man to the surface, where they resuscitated him. + +Equally good service, either in actual rescue operations, or in +explorations after mine disasters, or in fire-fighting, has been +rendered by this force at the Darr, Star Junction, Hazel, Clarinda, +Sewickley, Berwind-White No. 37, and Wehrum, Pa., mine disasters; at +Monongah and Lick Branch, W. Va.; at Deering, Sunnyside, and Shelburn, +Ind., Jobs, Ohio, and at Roslyn, Wash. + +_Explosives Laboratory._--The rooms grouped at the south end of Building +No. 21, at Pittsburg, are occupied as a laboratory for the chemical +examination and analysis of explosives, and are in charge of Mr. W. O. +Snelling. + +Samples of all explosives used in the testing gallery, ballistic +pendulum, pressure gauge, and other testing apparatus, are here +subjected to chemical analysis in order to determine the component +materials and their exact percentages. Tests are also made to determine +the stability of the explosive, or its liability to decompose at various +temperatures, and other properties which are of importance in showing +the factors which will control the safety of the explosive during +transportation and storage. + +In the investigation of all explosives, the first procedure is a +qualitative examination to determine what constituents are present. +Owing to the large number of organic and inorganic compounds which enter +into the composition of explosive mixtures, this examination must be +thorough. Several hundred chemical bodies have been used in explosives +at different times, and some of these materials can be separated from +others with which they are mixed only by the most careful and exact +methods of chemical analysis. + +Following the qualitative examination, a method is selected for the +separation and weighing of each of the constituents previously found to +be present. These methods, of course, vary widely, according to the +particular materials to be separated, it being usually necessary to +devise a special method of analysis for each explosive, unless it is +found, by the qualitative analysis, to be similar to some ordinary +explosive, in which case the ordinary method of analysis of that +explosive can be carried out. Most safety powders require special +treatment, while most grades of dynamite and all ordinary forms of black +blasting powder are readily analyzed by the usual methods. + +The examination of black blasting powder has been greatly facilitated +and, at the same time, made considerably more accurate, by means of a +densimeter devised at this laboratory. In this apparatus a Torricellian +vacuum is used as a means of displacing the air surrounding the grains +of powder, and through very simple manipulation the true density of +black powder is determined with a high degree of accuracy. In Building +No. 17 there is an apparatus for separating or grading the sizes of +black powder (Fig. 1, Plate X). + +By means of two factors, the moisture coefficient and the hygroscopic +coefficient, which have been worked out at this laboratory, a number of +important observations can be made on black powder, in determining the +relative efficiency of the graphite coating to resist moisture, and also +as a means of judging the thoroughness with which the components of the +powder are mixed. The moisture coefficient relates to the amount of +moisture which is taken up by the grains of the powder in a definite +time under standard conditions of saturation; and the hygroscopic +coefficient relates to the affinity of the constituents of the powder +for moisture under the same standard conditions. + +Besides the examination of explosives used at the testing station, those +for the Reclamation Service, the Isthmian Canal Commission, and other +divisions of the Government, are also inspected and analyzed at the +explosives laboratory. At the present time, the Isthmian Canal +Commission is probably the largest user of explosives in the world, and +samples used in its work are inspected, tested, and analyzed at this +laboratory, and at the branch laboratories at Gibbstown and Pompton +Lakes, N.J., and at Xenia, Ohio. + +Aside from the usual analysis of explosives for the Isthmian Canal +Commission, special tests are made to determine the liability of the +explosive to exude nitro-glycerine, and to deteriorate in unfavorable +weather conditions. These tests are necessary, because of the warm and +moist climate of the Isthmus of Panama. + +_Gas and Dust Gallery No. 1._--Gallery No. 1 is cylindrical in form, +100 ft. long, and has a minimum internal diameter of 6⅓ ft. It consists +of fifteen similar sections, each 6⅔ ft. long and built up in in-and-out +courses. The first three sections, those nearest the concrete head, are +of ½-in. boiler-plate steel, the remaining twelve sections are of ⅜-in. +boiler-plate steel, and have a tensile strength of, at least, 55,000 lb. +per sq. in. Each section has one release pressure door, centrally placed +on top, equipped with a rubber bumper to prevent its destruction when +opened quickly. In use, this door may be either closed and unfastened, +closed and fastened by stud-bolts, or left open. Each section is also +equipped with one ¾-in. plate-glass window, 6 by 6 in., centrally placed +in the side of the gallery (Fig. 1, and Figs. 1 and 2, Plate VI). The +sections are held together by a lap-joint. At each lap-joint there is, +on the interior of the gallery, a 2½-in. circular, angle iron, on the +face of which a paper diaphragm may be placed and held in position by +semicircular washers, studs, and wedges. These paper diaphragms are used +to assist in confining a gas-and-air mixture. + + [Illustration: Fig. 1. + + EXPLOSIVES TESTING GALLERY No. 1] + +Natural gas from the mains of the City of Pittsburg is used to represent +that found in the mines by actual analysis. A typical analysis of this +gas is as follows: + +Volumetric Analysis of Typical Natural Gas. + + Hydrogen gases 0 + Carbon dioxide 0.1 + Oxygen 0 + Heavy hydrocarbons 0 + Carbon monoxide 0 + Methane 81.8 + Ethane 16.8 + Nitrogen 1.3 + +The volume of gas used is measured by an accurate test meter reading to +one-twentieth of a cubic foot. The required amount is admitted near the +bottom, to one or more of the 20-ft. divisions of the gallery, from a +2-in. pipe, 14 ft. long. The pipe has perforations arranged so that an +equal flow of gas is maintained from each unit length. + +Each 20-ft. division of the gallery is further equipped with an exterior +circulating system, as shown by Fig. 1, thus providing an efficient +method of mixing the gas with the air. For the first division this +circulating system is stationary, a portion of the piping being equipped +with heating coils for maintaining a constant temperature. + +The other divisions have a common circulating system mounted on a truck +which may be used on any of these divisions. Valves are provided for +isolating the fan so that a possible explosion will not injure it. + +In the center section of each division is an indicator cock which is +used to provide means of recording pressures above and below +atmospheric, or of sampling the air-and-gas mixture. The first division +of the gallery is equipped with shelves laterally placed, for the +support of coal dust. + +The cannon in which the explosive is fired is placed in the concrete +head, the axial line of the bore-hole being coincident with that of the +gallery. This cannon (Fig. 2) is similar to that used in the ballistic +pendulum. The charge is fired electrically from the observation room. To +minimize the risk of loading the cannon, the charger carries in his +pocket the plug of a stage switch (the only plug of its kind on the +ground), so that it is impossible to complete the circuit until the +charger has left the gallery. That portion of the first division of the +gallery which is not embedded in concrete, has a 3-in. covering made up +of blocks of magnesia, asbestos fiber, asbestos, cement, a thin layer of +8-oz. duck, and strips of water-proof roofing paper, the whole being +covered with a thick coat of graphite paint. The object of this covering +is to assist in maintaining a constant temperature. + + [Illustration: PLATE VII. + + Fig. 1.--Bichel Pressure Gauges. + + Fig. 2.--Rate of Detonation Recorder.] + +The entire gallery rests on a concrete foundation 10 ft. wide, which has +a maximum height of 4½ ft. and a minimum height of 2 ft. + +The concrete head in which the cannon is placed completely closes that +end of the gallery. A narrow drain extends under the entire length of +the gallery, and a tapped hole at the bottom of each section provides an +efficient means of drainage. + + [Illustration: Fig. 2. + + {cannon as described in text} ] + +The buildings near the gallery are protected by two barricades near the +open end, each 10 ft. high and 30 ft. long. A back-stop, consisting of a +swinging steel plate, 6 ft. high and 9 ft. long, 50 ft. from the end of +the gallery, prevents any of the stemming from doing damage. + +Tests are witnessed from an observation room, a protected position about +60 ft. from the gallery. The walls of the room are 18 in. thick, and the +line of vision passes through a ½-in. plate glass, 6 in. wide and 37 ft. +long, and is further confined by two external guards, each 37 ft. long +and 3 ft. wide. + +In this gallery a series of experiments has been undertaken to determine +the amount of moisture necessary with different coal dusts, in order to +reduce the likelihood of a coal-dust explosion from a blown-out shot of +one of the dangerous types of explosives. + +Coal dust taken from the roads of one of the coal mines in the Pittsburg +district required at least 12% of water to prevent an ignition. It has +also been proven that the finer the dust the more water is required, and +when it was 100-mesh fine, 30% of water was required to prevent its +ignition by the flame of a blown-out shot in direct contact. The methods +now used in sprinkling have been proven entirely insufficient for +thoroughly moistening the dust, and hence are unreliable in preventing a +general dust explosion. + +At this station successful experiments have been carried out by using +humidifiers to moisten the atmosphere after the temperature of the air +outside the gallery has been raised to mine temperature and drawn +through the humidifiers. It has been found that if a relative humidity +of 90%, at a temperature of 60° Fahr., is maintained for 48 hours, +simulating summer conditions in a mine, the absorption of moisture by +the dust and the blanketing effect of the humid air prevent the general +ignition of the dust. + +These humidity tests have been run in Gas and Dust Gallery No. 1 with +special equipment consisting of a Koerting exhauster having a capacity +of 240,000 cu. ft. per hour, which draws the air out of the gallery +through the first doorway, or that next the concrete head in which the +cannon is embedded. + +The other end of the gallery is closed by means of brattice cloth and +paper diaphragms, the entire gallery being made practically air-tight. +The air enters the fifteenth doorway through a box, passing over steam +radiators to increase its temperature, and then through the humidifier +heads. + + +EXPLOSIVES TESTING APPARATUS. + +There is no exposed woodwork in Building No. 17, which is 40 by 60 ft., +two stories high, and substantially constructed of heavy stone masonry, +with a slate roof. The structure within is entirely fire-proof. Iron +columns and girders, and wooden girders heavily encased in cement, +support the floors which are either of cement slab construction or of +wooden flooring protected by expanded metal and cement mortar, both +above and beneath. At one end, on the ground floor, is the exposing and +recording apparatus for flame tests of explosives, also pressure gauges, +and a calorimeter, and, at the other end, is a gallery for testing +safety lamps. + +The larger portion of the second floor is occupied by a gas-tight +training room for rescue work, and an audience chamber, from which +persons interested in such work may observe the methods of procedure. A +storage room for rescue apparatus and different models of safety lamps +is also on this floor. + +The disruptive force of explosives is determined in three ways, namely, +by the ballistic pendulum, by the Bichel pressure gauge, and by Trauzl +lead blocks. + +_Ballistic Pendulum._--The disruptive force of explosives, as tested by +the ballistic pendulum, is measured by the amount of oscillation. The +standard unit of comparison is a charge of ½ lb. of 40% nitro-glycerine +dynamite. The apparatus consists essentially of a 12-in. mortar (Fig. 3, +Plate VI), weighing 31,600 lb., and suspended as a pendulum from a beam +having knife-edges. A steel cannon is mounted on a truck set on a track +laid in line with the direction of the swing of the mortar. At the time +of firing the cannon may be placed 1/16-in. from the muzzle of the +mortar. The beam, from which the mortar is suspended, rests on concrete +walls, 51 by 120 in. at the base and 139 in. high. On top of each wall +is a 1-in. base-plate, 7 by 48 in., anchored to the wall by ⅝-in. bolts, +28 in. long. The knife-edges rest on bearing-plates placed on these +base-plates. The bearing-plates are provided with small grooves for the +purpose of keeping the knife-edges in oil and protected from the +weather. The knife-edges are each 6 in. long, 2-11/16 in. deep from +point to back, 2 in. wide at the back, and taper 50° with the +horizontal, starting on a line 1½ in. from the back. The point is +rounded to conform to a radius of ¼ in. The back of each is 2 in. longer +than the edge, making a total length of 10 in., and is 1 in. deep and 12 +in. wide. This shoulder gives bolting surface to the beam from which the +mortar is hung. The beam is of solid steel, has a 4 by 8-in. section, +and is 87 in. long. Heavy steel castings are bolted to it to take the +threads of the machine-steel rods which form the saddles on which the +mortar is suspended. The radius of the swing, measured from the point of +the knife-edges to the center of the trunnions, is 89¾ in. + +The cannon consists of two parts, a jacket and a liner. The jacket is 36 +in. long, has an external diameter of 24 in., and internal diameters of +9½ and 7½ in. It is made of the best cast steel or of forged steel. + +The liner is 36½ in. long, with a 1-in. shoulder, 7¾ in. from the back, +changing the diameter from 9½ to 7½ in. The bore is smooth, being 2¼ in. +in diameter and 21½ in. long. The cannon rests on a 4-wheel truck, to +which it is well braced by straps and rods. A track of 30-in. gauge +extends about 9 ft. from the muzzle of the mortar to the bumper for the +cannon. + +The shot is fired by an electric firing battery, from the first floor of +Building No. 17, about 10 yd. away. To insure the safety of the operator +and the charger, the man who loads the cannon carries a safety plug +without which the charge cannot be exploded. The wires for connecting to +the fuse after charging are placed conveniently, and the safety plug is +then inserted in a box at the end of the west wall. The completion of +the firing battery by the switch at the firing place is indicated by the +flashing of a red light, after which all that is necessary to set off +the charge is to press a button on the battery. An automatic recording +device at the back of the mortar records the length of swing which, by a +vernier, may be read to 1/200 in. + +_Bichel Pressure Gauges._--Pressure gauges are constructed for the +purpose of determining the unit disruptive force of explosives +detonating at different rates of velocity, by measuring pressures +developed in an enclosed space from which the generated gases cannot +escape. The apparatus consists of a stout steel cylinder, which may be +made absolutely air-tight; an air-pump and proper connections for +exhausting the air in the cylinder to a pressure equivalent to 10 mm. of +mercury; an insulated plug for providing the means of igniting the +charge; a valve by which the gaseous products of combustion may be +removed for subsequent analysis; and an indicator drum (Fig. 1, Plate +VII) with proper connections for driving it at a determinable speed. + +This apparatus is in the southeast corner of Building No. 17. The +cylinder is 31½ in. long, 19¾ in. in diameter, and is anchored to +a solid concrete footing at a convenient height for handling. The +explosion chamber is 19 in. long and 7⅞in. in diameter, with a capacity +of exactly 15 liters. The cover of the cylinder is a heavy piece of +steel held in place by stout screw-bolts and a heavy steel clamp. + +The charge is placed on a small wire tripod, and connections are made +with a fuse to an electric firing battery for igniting the charges. The +cover is drawn tight, with the twelve heavy bolts against lead washers. +The air in the cylinder is exhausted to 10 mm., mercury column, in order +to approach more closely the conditions of a stemmed charge exploding in +a bore-hole inaccessible to air; the indicator drum is placed in +position and set in motion; and, finally, the shot is fired. The record +shown on the indicator card is a rapidly ascending curve for quick +explosives and a shallower, slowly rising curve for explosives of slow +detonation. When the gases cool, the curve merges into a straight line, +which indicates the pressures of the cooled gases on the sides of the +chamber. + + [Illustration: PLATE VIII. + + Fig. 1.--Explosives Calorimeter. + + Fig. 2.--Building No. 17, and Flame-Test Apparatus. + + Fig. 3.--Small Lead Block Test.] + +Since the ratio of the volume of the cylinder to the volume of the +charge may be computed, the pressure of the confined charge may also be +found, and this pressure often exceeds 100,000 lb. per sq. in. The +cooling effect of the inner surface on the gaseous products of +combustion, a vital point in computations of the disruptive force of +explosives by this method, is determined by comparing the pressures +obtained in the original cylinder with those in a second cylinder of +larger capacity, into which has been inserted one or more steel +cylinders to increase the superficial area while keeping the volume +equal to that of the first cylinders. By comparing results, a curve may +be plotted, which will determine the actual pressures developed, with +the surface-cooling effect eliminated. + +_Trauzl Lead Blocks._--The lead-block test is the method adopted by the +Fifth International Congress of Applied Chemistry as the standard for +measuring the disruptive force of explosives. The unit by this test is +defined to be the force required to enlarge the bore-hole in the block +to an amount equivalent to that produced by 10 grammes of standard 40% +nitro-glycerine dynamite stemmed with 50 grammes of dry sand under +standard conditions as produced with the tamping device. The results of +this test, when compared with those of the Bichel gauge, indicate that, +for explosives of high detonation, the lead block is quite accurate, but +for slow explosives, such as gunpowder, the expansion of the gases is +not fast enough to make comparative results of value. The reason for +this is that the gases escape through the bore of the block rather than +take effect in expanding the bore-hole. + +The lead blocks are cylindrical, 200 mm. in diameter, and 200 mm. high. +Each has a central cavity, 25 mm. in diameter and 125 mm. deep (Fig. 1, +Plate IX), in which the charge is placed. The blocks are made of +desilverized lead of the best quality, and, as nearly as possible, under +identical conditions. The charge is placed in the cavity and prepared +for detonation with an electrical exploder and stemming. After the +explosion the bore-hole is pear-shaped, the size of the cavity +depending, not only on the disruptive power of the explosive, but also +on its rate of detonation, as already indicated. The size of the +bore-hole is measured by filling the cavity with water from a burette. +The difference in the capacity of the cavity before and after detonation +indicates the enlarging power of the explosive. + +_Calorimeter._--The explosion calorimeter is designed to measure the +amount of heat given off by the detonation of explosive charges of 100 +grammes. The apparatus consists of the calorimeter bomb (Fig. 1, Plate +VIII), the inner receiver or immersion vessel, a wooden tub, a +registering thermometer, and a rocking frame. This piece of apparatus +stands on the east side of Building No. 17. + +The bottle-shaped bomb is made of ½-in. wrought steel, and has a +capacity of 30 liters. On opposite sides near the top are bored +apertures, one for the exhaust valve for obtaining a partial vacuum +(about 20 mm., mercury column) after the bomb has been charged, the +other for inserting the plug through which passes the fuse wire for +igniting the charge. The bomb is closed with a cap, by which the chamber +may be made absolutely air-tight. It is 30 in. high with the cap on, +weighs 158 lb., and is handled to and from the immersion vessel by a +small crane. + +The inner receiver is made of 1/16-in. sheet copper, 30⅞ in. deep, and +with an inner diameter of 17⅞ in. It is nickel-plated, and strengthened +on the outside with bands of copper wire, and its capacity is about 70 +liters. The outer tub is made of 1-in. lumber strengthened with four +brass hoops on the outside. It is 33 in. deep, and its inner diameter +is 21 in. + +The stirring device, operated vertically by an electric motor, consists +of a small wooden beam connected to a system of three rings having a +horizontal bearing surface. When the apparatus is put together, the +inner receiver rests on a small standard on top of the base of the outer +tank, and the rings of the stirring device are run between the bomb and +the inner receiver. The bomb itself rests on a small standard placed on +the bottom of the inner receiver. The apparatus is provided with a +snugly fitting board cover. The bomb is charged from the top, the +explosive being suspended in its center. The air is exhausted to the +desired degree of rarification. The caps are then screwed on, and the +apparatus is set together as described. + + [Illustration: PLATE IX. + + Fig. 1.--Trauzl Lead Blocks. + + Fig. 2.--Powder Flames.] + +The apparatus is assembled on scales and weighed before the water is +poured in and after the receiver is filled. From the weight of the water +thus obtained and the rise of temperature, the calorific value may be +computed. The charge is exploded by electricity, while the water is +being stirred. The rise in the temperature of the water is read by a +magnifying glass, from a thermometer which measures temperature +differences of 0.01 degree. From the readings obtained, the maximum +temperature of explosion may be determined, according to certain +formulas for calorimetric experiments. Proper corrections are made for +the effects, on the temperature readings, of the formation of the +products of combustion, and for the heat-absorbing power of the +apparatus. + +_Impact Machine._--In Building No. 17, at the south side, is an impact +machine designed to gauge the sensitiveness of explosives to shock. For +this purpose, a drop-hammer, constructed to meet the following +requirements, is used: A substantial, unyielding foundation; minimum +friction in the guide-grooves; and no escape or scattering of the +explosive when struck by the falling weight. This machine is modeled +after one used in Germany, but is much improved in details of +construction. + +The apparatus, Fig. 1, Plate XI, consists essentially of the following +parts: An endless chain working in a vertical path and provided with +lugs; a steel anvil on which the charge of explosive is held by a steel +stamp; a demagnetizing collar moving freely in vertical guides and +provided with jaws placed so that the lugs of the chain may engage them; +a steel weight sliding loosely in vertical guides and drawn by the +demagnetizing collar to determinable heights when the machine is in +operation; a second demagnetizing collar, which may be set at known +heights, and provided with a release for the jaws of the first collar; +and a recording device geared to a vertically-driven threaded rod which +raises or lowers, sets the second demagnetizing collar, and thus +determines the height of fall of the weight. By this apparatus the +weight may be lifted to different known heights, and dropped on the +steel stamp which transmits the shock to the explosive. The fall +necessary to explode the sample is thus determined. + +The hammers are of varying weight, the one generally used weighing +2,000 grammes. As the sensitiveness of an explosive is influenced by +temperature changes, water at 25° cent. is allowed to flow through the +anvil in order to keep its temperature uniform. + +_Flame Test._--An apparatus, Fig. 2, Plate VIII, designed to measure +the length and duration of flames given off by explosives, is placed at +the northeast corner of Building No. 17. It consists essentially of a +cannon, a photographing device, and a drum geared for high speed, to +which a sensitized film may be attached. + +About 13 ft. outside the wall of Building No. 17, set in a concrete +footing, is a cannon pointing vertically into an encasing cylinder or +stack, 20 ft. high and 43 in. in diameter. This cannon is a duplicate of +the one used for the ballistic pendulum, details of which have already +been given. The stack or cylinder is of ¼-in. boiler plate, in +twenty-four sections, and is absolutely tight against light at the base +and on the sides. It is connected with a dark room in Building No. 17 by +a light-tight conduit of rectangular section, 12 in. wide, horizontal on +the bottom, and sloping on the top from a height of 8¼ ft. at the stack +to 21 in. at the inside of the wall of the building. + +The conduit is carefully insulated from the light at all joints, and is +riveted to the stack. A vertical slit, 2 in. wide and 8 ft. long, +coincident with the center line of the conduit, is cut in the stack. A +vertical plane drawn through the center line of the bore-hole of the +cannon and that of the slit, if produced, intersects the center line of +a quartz lens, and coincides with the center of a stenopaic slit and the +axis of the revolving drum carrying the film. The photographing +apparatus consists of a shutter, a quartz lens, and a stenopaic slit, 76 +by 1.7 mm., between the lens and the sensitized film on the rotary drum. +The quartz lens is used because it will focus the ultra-violet rays, +which are those attending extreme heat. + +The drum is 50 cm. in circumference and 10 cm. deep. It is driven by a +220-volt motor connected to a tachometer which reads both meters per +second and revolutions per minute. A maximum peripheral speed of 20 m. +per sec. may be obtained. + +When the cannon is charged, the operator retires to the dark room in +which the recording apparatus is located, starts the drum, obtains the +desired speed, and fires the shot by means of a battery. When developed, +the film shows a blur of certain dimensions, produced by the flame from +the charge. From the two dimensions--height and lateral +displacement--the length and duration of the flame of the explosive are +determined. + +The results of flame tests of a permissible explosive and a test of +black blasting powder, all shot without stemming, are shown on Fig. 2, +Plate IX. In this test, the speed of the drum carrying the black powder +negative was reduced to one sixty-fourth of that for the permissible +explosives, in order that the photograph might come within the limits of +the negative. In other words, the duration of the black powder flame, as +shown, should be multiplied by 64 for comparison with that of the +permissible explosive, which is from 3,500 to 4,000 times quicker. + +_Apparatus for Measuring Rate of Detonation._--The rate at which +detonation travels through a given length of an explosive can be +measured by an apparatus installed in and near Building No. 17. Its most +essential feature is a recording device, with an electrical connection, +by which very small time intervals can be measured with great exactness. + +The explosive is placed in a sheet-iron tube about 1½ in. in diameter +and 4 ft. long, and suspended by cords in a pit, 11 ft. deep and 16 ft. +in diameter. This pit was once used as the well of a gas tank, Fig. 2, +Plate VIII. In adapting the pit to its new use, the tank was cut in two; +the top half, inverted, was placed in the pit on a bed of saw-dust, and +the space between the tank and the masonry walls of the pit was filled +with saw-dust. The cover of the pit consists of heavy timbers framed +together and overlaid by a 12-in. layer of concrete reinforced by six +I-beams. Four straps extend over the top and down to eight “deadmen” +planted about 8 ft. below the surface of the ground. + +The recording device, known as the Mettegang recorder, Fig. 2, Plate +VII, comprises two sparking induction coils and a rapidly revolving +metallic drum driven by a small motor, the periphery of the drum having +a thin coating of lampblack. A vibration tachometer which will indicate +any speed between 50 and 150 rev. per sec., is directly connected to the +drum, so that any chance of error by slipping is eliminated. The wires +leading to the primary coils of the sparking coils pass through the +explosive a meter or more apart. Wires lead from the secondary coils to +two platinum points placed a fraction of a millimeter from the periphery +of the drum. A separate circuit is provided for the firing lines. + +In making a test, the separate cartridges, with the paper trimmed from +the ends, are placed, end to end, in the sheet-iron tube; the drum is +given the desired peripheral speed, and the charge is exploded. The +usual length between the points in the tube is 1 m., and the time +required for the detonation of a charge of that length is shown by the +distance between the beginning of two rows of dots on the drum made by +the sparks from the secondary coil circuits, the dots starting the +instant the primary circuits are broken by the detonation. At one end of +the drum are gear teeth, 1 mm. apart on centers, which can be made to +engage a worm revolving a pointer in front of a dial graduated to +hundredths; by means of this and a filar eyepiece, the distance between +the start of the two rows of spark dots on the drum can be measured +accurately to 0.01 mm. As the drum is 500 mm. in circumference, and its +normal speed is 86 rev. per sec., it is theoretically possible to +measure time to one four-millionth of a second, though with a cartridge +1 m. long, such refinement has not been found necessary. + +The use of small lead blocks affords another means of determining the +rate of detonation or quickness of an explosive. Each block (a cylinder, +2½ in. long and 1½ in. in diameter) is enclosed in a piece of paper so +that a shell is formed above the block, in which to place the charge. A +small steel disk of the same diameter as the block is first placed in +the shell on top of the block, then the charge with a detonator is +inserted. The charge is customarily 100 grammes. On detonation of the +charge, a deformation of the lead takes place, the amount of which is +due to the quickness of the explosive used (Fig. 3, Plate VIII). + +Sample Record of Tests. + +The procedure followed in the examination of an explosive is shown by +the following outline: + +1.--_Physical Examination._ + + (_a_).--Record of appearance and marks on original package. + + (_b_).--Dimensions of cartridge. + + (_c_).--Weight of cartridge, color and specific gravity of powder. + +2.--_Chemical Analysis._ + + (_a_).--Record of moisture, nitro-glycerine, sodium or potassium + nitrate, and other chemical constituents, as set forth by the + analysis; percentage of ash, hygroscopic coefficient--the amount of + water taken up in 24 hours in a saturated atmosphere, at 15° cent., + by 5 grammes, as compared with the weight of the explosive. + + (_b_).--Analysis of products of combustion from 100 grammes, including + gaseous products, solids, and water. + + (_c_).--Composition of gaseous products of combustion, including + carbon monoxide and carbon dioxide, hydrogen, nitrogen, etc. + + (_d_).--Composition of solid products of combustion, subdivided into + soluble and insoluble. + +_3.--A Typical Analysis of Natural Gas._ + +Used in tests, as follows: + + Carbon dioxide 0.0 per cent. + Heavy hydrocarbons 0.2 ” ” + Oxygen 0.1 ” ” + Carbon monoxide 0.0 ” ” + Methane 82.4 ” ” + Ethane 15.3 ” ” + Nitrogen 2.0 ” ” + ----- + 100.00 per cent. + +_4.--Typical Analysis of Bituminous Coal Dust, 100-Mesh Fine, Used in +Tests._ + + Moisture 1.90 + Volatile matter 35.05 + Fixed carbon 58.92 + Ash 4.13 + ------ + 100.00 + Sulphur 1.04 + +_5.--An Average Analysis of Detonators._ + +Used on Trauzl lead blocks, pressure gauge, calorimeter, and small lead +blocks: + + M - l(l/m). Triple-strength exploder. + + Charge 1.5729 grammes. + + Mercury Chlorate + fulminate. of potash. + Specification 89.73 10.27 + +Used on all other tests: + + M - 260(l/m). Double-strength exploder. + + Charge 0.9805 grammes. + + Mercury Chlorate + fulminate. of potash. + Specification 91.31 8.69 + +_6.--Ballistic-Pendulum Tests._ + +This record includes powder used, weight of charge, swing of mortar, and +unit disruptive charge, the latter being the charge required to produce +a swing of the mortar equal to that produced by ½ lb. (227 grammes) of +40% dynamite, or 3.01 in. + +_7.--Record of Tests._ + +Tests Nos. 1 to 5 in Gallery No. 1, as set forth in preceding circular. + +_8.--Trauzl Lead-Block Test._ + +Powder and test numbers, expansion of bore-hole in cubic centimeters, +and average expansion compared with that produced by a like quantity (10 +grammes) of 40% dynamite, the latter giving an average expansion of 294 +cu. cm. + +_9.--Pressure Gauge._ + +Powder and test number, weight of charge, charging density, height of +curve, pressure developed, and pressure developed after cooling, +compared with pressure developed after elimination of surface influences +by a like quantity (100 grammes) of 40% dynamite, the average being +8,439 kg. per sq. cm. + +_10.--Rate of Detonation._ + +Powder and test number, size of cartridge, and rate of detonation in +meters per second, for comparison with rate of detonation of 40% +dynamite, which, under the same conditions, averages 4,690 m. per sec. + +_11.--Impact Machine._ + +Explosive and test numbers, distance of fall (2,000-gramme weight) +necessary to cause explosion, for comparison with length of fall, 11 +cm., necessary to cause explosion of 40% dynamite. + +_12.--Distance of Explosive Wave Transmitted by 1.25 by 8-in. +Cartridge._ + +Explosive and test numbers, weight of cartridge, distance separating +cartridges in tests, resulting explosion or non-explosion, for +comparison with two cartridges of 40% dynamite, hung, under identical +conditions, 13 in. apart, end to end, in which case detonation of the +first cartridge will explode the second. + +_13.--Flame Test._ + +Explosive and test numbers, charge 100 grammes with 1 lb. of clay +stemming, average length of flame and average duration of flame, for +comparison with photographs produced by 40% dynamite under like +conditions. + + [Illustration: PLATE X. + + Fig. 1.--Separator for Grading Black Powder. + + Fig. 2.--Safety Lamp Testing Gallery. + + Fig. 3.--Mine Gallery No. 2.] + +_14.--Small Lead Blocks._ + +Powder and test numbers, weight of charge, and compression produced in +blocks. + +_15.--Calories Developed._ + +Number of large calories developed per kilogramme of explosive, for +comparison with 1,000 grammes of 40% dynamite, which develop, on an +average, 1,229 large calories. + +Blasting Powder Separator. + +The grains of black blasting powder are graded by a separator, similar +to those used in powder mills, but of reduced size. It consists of an +inclined wooden box, with slots on the sides to carry a series of +screens, and a vertical conduit at the end for carrying off the grains +as they are screened into separate small bins (Fig. 1, Plate X). At the +upper end of the screens is a small 12 by 16-in. hopper, with a sliding +brass apron to regulate the feed. The screens are shaken laterally by an +eccentric rod operated by hand. The top of the hopper is about 6½ ft. +above the floor. The box is 6 ft. 10 in. long, from tip to tip, and +inclines at an angle of 9 degrees. + +After separation the grains fall through a vertical conduit, and thence +to the bins through zinc chutes, 1 by 2 in. in section. Care is taken to +have no steel or iron exposed to the powder. + +The screens are held by light wooden frames which slip into the inclined +box from the upper end. In this way, any or all of the screens may be +used at once, thus separating all grades, or making only such +separations as are desired. The screens with the largest meshes are +diagonally-perforated zinc plates. Table 2 gives the number of holes per +square foot in zinc plates perforated with circular holes of the +diameters stated. + + TABLE 2.--Number of Holes per Square Foot in Zinc Plates with Circular + Perforations. + + -------------+------------ + Diameter, | Number + in inches | of holes. + -------------+------------ + 1/2 | 353 + 4/10 | 518 + 1/3 | 782 + 1/4 | 1,392 + 1/6 | 1,680 + 1/8 | 3,456 + 1/10 | 6,636 + 1/16 | 12,800 + -------------+------------ + +The finer meshes are obtained by using linen screens with holes of two +sizes, namely, 1/20 in. square and 1/28 in. square. + +Until a few years ago, black blasting powder was manufactured in the +sizes given in Table 3. + + TABLE 3.--Gradation of Black Blasting Powder. + + ---------+----------- + Grade. | Mesh. + ---------+----------- + CC | 2 - 2½ + C | 2½ - 3 + F | 3 - 5 + FF | 5 - 8 + FFF | 8 - 16 + FFFF | 16 - 28 + ---------+----------- + +In late years there has been considerable demand for special sizes and +mixed grains for individual mines, especially in Illinois. As no +material change has been made in the brands, the letters now used are +not indicative of the size of the grains, which they are supposed to +represent. Of 29 samples of black blasting powder recently received from +the Illinois Powder Commission, only 10 were found to contain 95% of the +size of grains they were supposed to represent; 4 contained 90%; 7 +varied from 80 to 90%; several others were mixtures of small and large +grains, and were branded FF black blasting powder; and one sample +contained only 8.5% of the size of grains it was supposed to represent. +The remaining samples showed many variations, even when sold under the +same name. The practice of thus mixing grades is exceedingly dangerous, +because a miner, after becoming accustomed to one brand of FF powder of +uniform separation, may receive another make of similar brand but of +mixed grains, and, consequently, he cannot gauge the quantity of powder +to be used. The result is often an over-load or a blown-out shot. The +smaller grains will burn first, and the larger ones may be thrown out +before combustion is complete, and thus ignite any fire-damp present. + +Lamp Testing Gallery. + +At the Pittsburg testing station, there is a gallery for testing safety +lamps in the presence of various percentages of inflammable gas. In this +gallery the safety of the lamps in these gaseous mixtures may be tested, +and it is also possible for mine inspectors and fire bosses to bring +their safety lamps to this station, and test their measurements of +percentage of gas, by noting the length and the appearance of the flame +in the presence of mixtures containing known percentages of methane and +air. + + [Illustration: PLATE XI. + + Fig. 1.--Impact Machine. + + Fig. 2.--Lamp Testing Box.] + +The gas-tight gallery used for testing the lamps, consists of a +rectangular conduit (Fig. 2, Plate X), having sheet-steel sides, 6 mm. +thick and 433 mm. wide, the top and bottom being of channel iron. The +gallery rests on two steel trestles, and to one end is attached a No. 5 +Koerting exhauster, capable of aspirating 50 cu. m. per min., under a +pressure of 500 mm. of water, with the necessary valve, steam separator, +etc. The mouth of the exhauster passes through the wall of the building +and discharges into the open air. + +Besides the main horizontal conduit, there are two secondary conduits +connected by a short horizontal length, and the whole is put together so +that the safety lamp under test may be placed in a current of air, or of +air and gas, which strikes it horizontally, vertically upward or +downward, or at an angle of 45° (Fig. 3). The path of the current is +determined by detachable sheet-steel doors. + + [Illustration: Fig. 3. + + SAFETY LAMP TESTING GALLERY] + +There are five double observing windows of plate glass, which open on +hinges. The size of each window is 7½ by 3 in.; the inner glass is ¼ in. +thick and the outer one, ½ in. thick. These glasses are separated by a +space of ¼ in. The upper conduit has four safety doors along the top, +each of the inclined conduits has one safety door, and the walls and +windows are provided with rubber gaskets or asbestos packing, to make +them gas-tight. The cross-sectional area of the conduit is 434 sq. cm. + +The air inlet consists of 36 perforations, 22 mm. in diameter, in a +bronze plate or diaphragm. The object of this diaphragm is to produce +pressure in the conduit before the mixing boxes, and permit the +measuring of the velocity of the current. The air-current, after passing +through the holes, enters the mixer, a cast-steel box traversed by 36 +copper tubes, each perforated by 12 openings, 3 mm. in diameter, +arranged in a spiral along its length and equally spaced. The total +cross-sectional area of the tubes is 137 sq. cm. + +The explosive gas enters the interior of the box around the tubes +through large pipes, each 90 mm. in diameter, passes thence through the +432 openings in the copper tubes, and mixes thoroughly with the air +flowing through these tubes. The current through the apparatus is +induced by the exhauster, and its course is determined by the position +of the doors. + +The gallery can be controlled so as to provide rapidly and easily a +current of known velocity and known percentage of methane. In the +explosive current of gas and air, safety lamps of any size or design can +be tested under conditions simulating those found occasionally in mines, +air-currents containing methane in dangerous proportions striking the +lamps at different angles, and the relative safety of the various types +of lamps under such conditions can be determined. In this gallery it is +also possible to test lighting devices either in a quiet atmosphere or +in a moving current, and, by subjecting the lamps to air containing +known percentages of methane, it is possible to acquaint the user with +the appearance of the flame caps. + +Breathing Apparatus. + +With this apparatus, the wearer may explore a gaseous mine, approach +fires for the purpose of fighting them, or make investigations after an +explosion. Its object is to provide air or oxygen to be breathed by the +wearer in coal mines, when the mine air is so full of poisonous gases as +to render life in its presence impossible. + +A variety of forms of rescue helmets and apparatus are on the market, +almost all of European manufacture, which are being subjected to +comparative trials as to their durability and safety, the ease or +inconvenience involved in their use, etc. All consist essentially of +helmets which fit air-tight about the head, or of air-tight nose clamps +and mouthpieces (Fig. 1, Plate XII). + +These several forms of breathing apparatus are of three types: + +1.--The liquid-air type, in which air, in a liquid state, evaporates and +provides a constant supply of fresh air. + +2.--The chemical oxygen-producing type, which artificially makes or +supplies oxygen for breathing at about the rate required; and, + +3.--The compressed-oxygen type. + + [Illustration: PLATE XII. + + Fig. 1.--Breathing and Rescue Apparatus. + + Fig. 2.--Rescue Training Room.] + +Apparatus of the first type, weighing 20 lb., supplies enough air to +last about 3 hours, and the products of breathing pass through a +check-valve directly into space. Apparatus of the second type supplies +oxygen obtained from oxygen-producing chemicals, and also provides means +of absorbing the carbonic acid gas produced in respiration. They contain +also the requisite tubes, valves, connections, etc., for the +transmission of the fresh air and the respired air so as to produce +sufficient oxygen while in use; to absorb and purify the products of +expiration; and to convey the fresh air to the mouth without +contamination by the atmosphere in which the apparatus is used. Three +oxygen-generating cartridges are provided, each supplying oxygen enough +for 1 hour, making the total capacity 3 hours. Changes of cylinders can +be made in a few seconds while breathing is suspended. This apparatus +weighs from 20 to 25 lb., according to the number of oxygen generators +carried. The cartridges for generating oxygen, provided with this +apparatus, are of no value after having been used for about an hour. + +The third type of apparatus is equipped with strong cylinders charged +with oxygen under high pressure; two potash regenerative cans for +absorbing the carbon dioxide gas exhaled; a facial helmet; the necessary +valves, tubes, etc., for the control of the oxygen; and a finimeter +which registers the contents of the cylinders in atmospheres and minutes +of duration. The two cartridges used for absorbing the carbonic acid gas +are of no value after having been in use for two hours. + +If inhalation is through the mouth alone, a mouthpiece is attached to +the end of the breathing tube by which the air or oxygen is supplied, +the nose is closed by a clip, and the eyes are protected by goggles. To +inhale through both nose and mouth, the miner wears a helmet or headgear +which can be made to fit tightly around the face. The helmet has two +tubes attached, one for inspiration and the other for expiration. In the +oxygen-cylinder apparatus these tubes lead to and from rubber sacks used +for pure-air and bad-air reserves. + +Mine-Rescue Training. + +It has been found in actual service that when a miner, equipped with +breathing apparatus for the first time, enters a mine in which an +explosion has occurred, he is soon overcome by excitement or nervousness +induced by the artificial conditions of breathing imposed by the +apparatus, the darkness and heat, and the consciousness that he is +surrounded with poisonous gases. It has also been found that a brief +period of training in the use of such apparatus, under conditions +simulating those encountered in a mine after a disaster, gives the miner +confidence and enables him to use the apparatus successfully under the +strain of the vigorous exertion incident to rescue work. + +The rescue corps consists of five or six miners under the direction of +a mining engineer who is experienced in rescue operations and familiar +with the conditions existing after mine disasters. The miners work in +pairs, so that one may assist the other in case of accident, or of +injury to the breathing apparatus, and so that each may watch the +condition of the oxygen supply, as shown by the gauges in the other’s +outfit. + +The training is given in the gas-tight room of Building No. 17, or in +similar rooms at sub-stations (Fig. 2, Plate XII). This room is made +absolutely dark, and is filled with formaldehyde gas, SO_{2}, CO_{2}, or +CO, produced by burning sulphur or charcoal on braziers. At each period +of training, the miners enter and walk a distance of about 1 mile, the +average distance usually traveled from the mine mouth to the working +face or point of explosion. They then remove a number of timbers; lift a +quantity of brick or hard lump-coal into wheel-barrows; climb through +artificial tunnels, up and down inclines, and over surfaces strewn with +coal or stone; operate a machine with a device attached to it, which +automatically records the foot-pounds of work done; and perform other +vigorous exercise, during a period of 2 hours. This routine is repeated +daily during 1 week, after which the rescue corps is considered +sufficiently trained for active service. + +The apparatus used for recording the foot-pounds of work done by the +person operating the work machine within the gas-tight rescue room, +comprises a small dial with electrical connections, which records the +number of strokes made by the machine, and a pencil point which rests on +a paper diaphragm, fastened to a horizontal brass disk. This disk is +driven by clockwork, and makes one complete revolution per hour. When +the machine is in operation, the pencil point works back and forth, +making a broad line on the paper; when the operator of the machine +rests, the pencil point traces a single line. The apparatus thus records +the number of strokes given by the operator during a given time. From +the weight lifted, the height of lift, and the number of strokes in the +given time, the foot-pounds of work are readily calculated. + +Electric Testing Apparatus. + +On the ground floor of Building No. 10, two rooms are occupied as +laboratories for investigating the electrical equipment used in mining +operations. The purpose of these investigations is to ascertain the +conditions under which electricity of various voltages may be used with +safety--in mine haulage, hoisting, pumping, or lighting--in the presence +of dangerous mixtures of explosive gases or of dust. It is also proposed +to test various kinds of insulation and insulators in this laboratory, +and to determine the durability of such insulation in the presence of +such corrosive gases and water as are found in mines. + +A water-proof wooden tank, measuring 15 by 5 by 5 ft., is installed, in +which insulation and insulating materials are tested under either pure +or polluted water. Various electric lighting devices and equipment can +be connected from a switch-board in Building No. 17 with Gas-and-Dust +Gallery No. 2, for testing the effect of such lighting apparatus in the +presence of explosive mixtures of gas and dust, as set forth on page +220. + +In the electrical laboratory, Building No. 10, is a booster set +developing 60 kw., and an appropriate switch-board for taking direct +current at 220 volts from the turbo-generator and converting it into +current varying from 0 to 750 volts. There are also transformers for +developing 60-cycle, alternating current at voltages of from 110 to +2,200. The switch-board is designed to handle these various voltages and +to communicate them to the apparatus under test in Building No. 10, +Gallery No. 2, or elsewhere. + +Tests are in progress of insulating materials for use in mines, and of +electric fuses, lights, etc., in Gallery No. 2 (Fig. 3, Plate X), and in +the lamp-testing box (Fig. 2, Plate XI). It is proposed, at the earliest +possible date, to make comparative tests of the safety of various mine +locomotives and mine-hoisting equipment through the medium of this +laboratory, and it is believed that the results will furnish valuable +information as a guide to the safety, reliability, and durability of +these appliances when electrically operated. + +_Electric Lamp and Fuse Testing Box._--An apparatus for testing safety +lamps and electric lights and fuses, consists of ¼-in. iron plates, +bolted together with 1½ in. angle-irons to form a box with inside +dimensions of 18 by 18 by 24 in. The box is placed on a stand at such a +height that the observation windows are on a level with the observer’s +eye (Fig. 2, Plate XI), and it is connected, by a gas-pipe, with a +supply of natural gas which can be measured by a gas-holder or meter +alongside the box. + +By the use of this apparatus the effect of explosive gas on flames, of +electric sparks on explosive mixtures of gas and air, and of breaking +electric lamps in an explosive mixture of gas and air, may be studied. +The safety lamps are introduced into the box from beneath, through a +hole 6 in. square, covered with a hinged iron lid, admission to which is +had through a flexible rubber sleeve, 20 in. long. + +The behavior of the standard safety lamp and of the safety lamps +undergoing test may be compared in this box as to height of flame for +different percentages of methane in the air, the effect of such flames +in igniting gas, etc. + +In each end of the box is an opening 1 ft. square, over which may be +placed a paper diaphragm held by skeleton doors, the purpose of which +is to confine the gas in such a manner that, should an explosion occur, +no damage would be done. In the front of the box are two plate-glass +observing windows, 2⅝ by 5½ in. In the side of the box, between the +two windows, is a ⅜-in. hole, which can be closed by a tap-screw, +through which samples for chemical analysis are drawn. + +The gasometer consists of two iron cans, the lower one being open at +the top and filled with water and the upper one open at the bottom and +suspended by a counterweight. The latter has attached to its upper +surface a scale which moves with it, thereby measuring the amount of +gas in the holder. A two-way cock permits the admission of gas into the +gasometer and thence into the testing box. + +_Gas-and-Dust Gallery No. 2._--This gallery is constructed of sheet +steel and is similar to Gallery No. 1, the length, however, being only +30 ft. and the diameter 10 ft. It rests on a concrete foundation (Fig. +3, Plate X). Diaphragms can be placed across either extremity, or at +various sections, to confine the mixtures of gas and air in which the +tests are made. The admission of gas is controlled by pipes and valves, +and the gas and air can be stirred or mixed by a fan, as described for +Gallery No. 1, and as shown by Fig. 1. + +Gallery No. 2 is used for investigating the effect of flames of various +lamps, of electric currents, motors, and coal-cutting machines, in the +presence of known mixtures of explosive gas and air. It is also used for +testing the length of flame of safety lamps in still air carrying +various proportions of methane, and, for this purpose, is more +convenient than the lamp gallery. In tests with explosive mixtures, +after the device to be tested has been introduced and preparations are +completed, operations are controlled from a safe distance by a +switch-board in a building near-by. + +Among other investigations conducted in this gallery are those of the +effect of sparks on known gas mixtures. These sparks are such as those +struck from a pick on flint, but in this case they are produced by +rubbing a rapidly revolving emery wheel against a steel file. The effect +of a spark produced by a short circuit of known voltage, the flame from +an arc lamp, etc., may also be studied in this gallery. + + +STRUCTURAL MATERIALS INVESTIGATIONS. + +The structural materials investigations are being conducted for the +purpose of determining the nature and extent of the materials available +for use in the building and construction work of the Government, and how +these materials may be used most efficiently. + +These investigations include: + +(1).--Inquiries into the distribution and local availability, near each +of the building centers in the United States, of such materials as are +needed by the Government. + +(2).--How these materials may be used most efficiently. + +(3).--Their fire-resisting qualities and strength at different +temperatures. + +(4).--The best and most economic methods of protecting steel by +fire-resistant covering. + +(5).--The most efficient methods of proportioning and mixing the +aggregate, locally available, for different purposes. + +(6).--The character and value of protective coatings, or of various +mixes, to prevent deterioration by sea water, alkali, and other +destructive agencies. + +(7).--The kinds and forms of reinforcement for concrete necessary to +secure the greatest strength in beams, columns, floor slabs, etc. + +(8).--Investigation of the clays and of the products of clays needed in +Government works, as to their strength, durability, suitability as +fire-resisting materials, and the methods of analyzing and testing clay +products. + +(9).--Tests of building stones, and investigations as to their +availability near the various building centers throughout the United +States. + +The operations of the Structural Materials Division include +investigations into cement-making materials, constituent materials of +concrete, building stones, clays, clay products, iron, steel, and +miscellaneous materials of construction, for the use of the Government. +The organization comprises a number of sections, including those for the +chemical and physical examination of Departmental purchases; field +sampling and laboratory examination of constituent materials of concrete +collected by skilled field inspectors in the neighborhood of the larger +commercial and building centers; similar field sampling of building +stones and of clays and clay products, offered for use in Government +buildings or engineering construction; and the forwarding of such +samples to the testing laboratories at St. Louis or Pittsburg for +investigation and test. The investigative tests include experiments +regarding destructive agencies, such as electrolysis, alkaline earths +and waters, salt water, fire, and weathering; also experiments with +protective and water-proofing agencies, including the various washes or +patented mixtures on the market, and the methods of washing, and mixing +mortars and concrete, which are likely to result in rendering such +materials less pervious to water. + +Investigations are also being conducted to determine the nature and +extent of materials available for use in the building-construction work +of the Government, and how these materials may be used most efficiently +and safely. While the act authorizing this work does not permit +investigations or tests for private parties, it is believed that these +tests for the Government cannot fail to be of great general value. The +aggregate expenditure by the Federal Government in building and +engineering construction is about $40,000,000 annually. This work is +being executed under so many different conditions, at points so widely +separated geographically, and requires so great a variety of materials, +that the problems to be solved for the Government can hardly fail to +cover a large share of the needs of the Engineering Profession, State +and municipal governments, and the general public. + +_Character of the Work._--The tests and analyses, of the materials of +construction purchased by the various bureaus and departments for the +use of the Government, are to determine the character, quality, +suitability, and availability of the materials submitted, and to +ascertain data leading to more accurate working values as a basis for +better working specifications, so as to enable Government officials to +use such materials with more economy and increased efficiency. + +Investigative tests of materials entering into Government construction, +relative to the larger problems involved in the use of materials +purchased by the Government, include exhaustive study of the suitability +for use, in concrete construction on the Isthmian Canal, of the sand and +stone, and of the cementing value of pozzuolanic material, found on the +Isthmus; the strength, elasticity, and chemical properties of structural +steel for canal lock-gates; of wire rope and cables for use in hoisting +and haulage; and the most suitable sand and stone available for concrete +and reinforced concrete for under-water construction, such as the +retaining walls being built by the Quartermaster’s Department of the +Army, in San Francisco Harbor. + +These tests also include investigations into the disintegrating effect +of alkaline soil and water on the concrete and reinforced concrete +structures of the Reclamation Service, with a view to preventing such +disintegration; investigations into the proper proportions and +dimensions of concrete and reinforced concrete structural columns, +beams, and piers, and of walls of brick and of building stone, and of +the various types of metal used for reinforcement by the Supervising +Architect in the construction of public buildings; investigations into +the sand, gravel, and broken stone available for local use in concrete +construction, such as columns, piers, arches, floor slabs, etc., as a +guide to the more economical design of public structures, and to +determine the proper method of mixing the materials to render the +concrete most impervious to water and resistant to weather and other +destructive agencies. + +Other lines of research may be stated briefly as follows: + +The extent to which concrete made from cement and local materials can be +most safely and efficiently used for different purposes under different +conditions; + +The best methods for mixing and utilizing the various constituent +materials locally available for use in Government construction; + +The materials suitable for the manufacture of cement on the public +lands, or where the Government has planned extensive building or +engineering construction work, where no cement plants now exist; + +The kinds and forms of reinforcement for concrete, and the best methods +of applying them in order to secure the greatest strength in +compression, tension, shear, etc., in reinforced concrete beams, +columns, floor slabs, etc.; + +The influence of acids, oils, salts, and other foreign materials, +long-continued strain, or electric currents, on the permanence of the +steel in reinforced concrete; + +The value of protective coatings as preventives of deterioration of +structural materials by destructive agencies; and + +The establishment of working stresses for various structural materials +needed by the Government in its buildings. + +Investigations are being made into the effects of fire and the rate of +conductivity of heat on concrete and reinforced concrete, brick, tile, +building stone, etc., as a guide to the use of the most suitable +materials for fire-proof building construction and the proper +dimensioning of fire-resistive coverings. + +Investigations and tests are being made, with a view to the preparation +of working specifications for use in Government construction, of bricks, +tile, sand-lime brick, paving brick, sewer pipe, roofing slates, +flooring tiles, cable conduits, electric insulators, architectural terra +cotta, fire-brick, and all shapes of refractories and other clay +products, regarding which no satisfactory data for the preparation of +specifications of working values now exist. + +Investigations of the clay deposits throughout the United States are in +progress, to determine proper methods of converting them into building +brick, tile, etc., at the most reasonable cost, and the suitability of +the resulting material for erection in structural forms and to meet +building requirements. + +Investigations are being made in the field, of building stones locally +available, and physical and chemical tests of these building stones to +determine their bearing or crushing strength; the most suitable mortars +for use with them; their resistance to weathering; their fire-resistive +and fire-proof qualities, etc., regarding which practically no adequate +information is available as a guide to Government engineering and +building design. + +_Results Accomplished._--During one period of six months alone, more +than 2,500 samples, taken from Government purchases of structural +materials, were examined, of which more than 300 failed to meet the +specified requirements, representing many thousands of dollars worth of +inferior material rejected, which otherwise would have been paid for by +the Government. These tests were the means of detecting the inferior +quality of large quantities of materials delivered on contracts, and the +moral effect on bidders has proven as important a factor in the +maintenance of a high quality of purchases, as in the saving of money. + +The examination of sands, gravels, and crushed stones, as constituent +materials for concrete and reinforced concrete construction, has +developed data showing that certain materials, locally available near +large building centers and previously regarded as inferior in quality, +were, in fact, superior to other and more expensive materials which it +had been proposed to use. + +These investigations have represented an actual saving in the cost of +construction on the work of the Isthmian Canal Commission, of the +Supervising Architect, and of certain States and cities which have +benefited by the information disseminated regarding these constituent +materials. + +Investigations of clay products, only recently inaugurated, have already +resulted in the ascertainment of important facts relative to the colloid +matter of clay and its measurement, and the bearing thereof on the +plasticity and working values of various clays. The study of the +preliminary treatment of clays difficult to handle dry, has furnished +useful information regarding the drying of such clays, and concerning +the fire resistance of bricks made of soft, stiff, or dried clay of +various densities. + +The field collection and investigation of building-stone samples have +developed some important facts which had not been considered previously, +relative to the effect of quarrying, in relation to the strike and dip +of the bedding planes of building stone, and the strength and durability +of the same material when erected in building construction. These +investigations have also developed certain fundamental facts relative to +the effects of blasting (as compared with channeling or cutting) on the +strength and durability of quarried building stone. + +_Mineral Chemistry Laboratories._--Investigations and analyses of the +materials of engineering and building construction are carried on at +Pittsburg in four of the larger rooms of Building No. 21. In this +laboratory, are conducted research investigations into the effect of +alkaline waters and soils on the constituent materials of concrete +available in arid regions, as related to the life and permanency of the +concrete and reinforced concrete construction of the Reclamation +Service. These investigations include a study of individual salts found +in particular alkalis, and a study of the results of allowing solutions +of various alkalis to percolate through cylinders of cement mortar and +concrete. Other research analyses have to do with the investigation of +destructive and preservative agencies for concrete, reinforced concrete, +and similar materials, and with the chemistry of the effects of salt +water on concrete, etc. The routine chemical analyses of the constituent +materials of concrete and cement-making materials, are made in this +laboratory, as are also a large number of miscellaneous chemical +analyses and investigations of reinforcement metal, the composition of +building stones, and allied work. + +A heat laboratory, in charge of Dr. J. K. Clement, occupies three rooms +on the ground floor of Building No. 21, and is concerned chiefly with +the measurement of temperatures in gas producers, in the furnaces of +steam boilers, kilns, etc. The work includes determinations of the +thermal conductivity of fire clays, concrete, and other building +materials, and of their fire-resisting properties; measurements of the +thermal expansion and specific heats of fire-bricks, porcelain, and +glazes; and investigations of the effect of temperature variations on +the various chemical processes which take place in the fuel bed of the +gas producer, boiler furnace, etc. + +The heat laboratory is equipped for the calibration of the thermometers +and pyrometers, and electrical and other physical apparatus used by the +various sections of the Technologic Branch. + +For convenience in analyzing materials received from the various +purchasing officers attached to the Government bureaus, this work is +housed in a laboratory on the fourth floor of the Geological Survey +Building in Washington. + +Large quantities and many varieties of building materials for use in +public buildings under contract with the Supervising Architect’s office, +are submitted to the laboratory by contractors to determine whether or +not they meet the specified requirements. Further examinations are made +of samples submitted by superintendents of construction, representing +material actually furnished by contractors. It is frequently found that +the sample of material submitted by the contractor is of far better +quality than that sent by the superintendent to represent deliveries. +The needed constant check on deliveries is thus provided. + +In addition to this work for the office of the Supervising Architect, +similar work on purchases and supplies is carried on for the Isthmian +Canal Commission, the Quartermaster-General’s Department of the Army, +the Life Saving Service, the Reclamation Service, and other branches of +the Government. About 300 samples are examined each month, requiring an +average of 12 determinations per sample, or about 3,600 determinations +per month. + +The chemical laboratory for testing Government purchases of structural +materials is equipped with the necessary apparatus for making the +requisite physical and chemical tests. For the physical tests of cement, +there are a tensile test machine, briquette moulds, a pat tank for +boiling tests to determine soundness, water tanks for the storage of +briquettes, a moist oven, apparatus to determine specific gravity, +fineness of grinding, etc. + +The chemical laboratory at Washington is equipped with the necessary +analytical balances, steam ovens, baths, blast lamps, stills, etc., +required in the routine chemical analysis of cement, plaster, clay, +bricks and terra cotta, mineral paints and pigments, roofing material, +tern plate and asphaltic compounds, water-proofing materials, iron and +steel alloys, etc. + +At present, materials which require investigative tests as a basis for +the preparation of suitable specifications, tests not connected with the +immediate determination as to whether or not the purchases are in +accordance with the specifications, are referred to the chemical +laboratories attached to the Structural Materials Division, at +Pittsburg. + +The inspection and tests of cement purchased in large quantities, such +as the larger purchases on behalf of public-building construction under +the Supervising Architect, or the great 4,500,000-bbl. contract of the +Isthmian Canal Commission, are made in the cement-testing laboratory of +the Survey, in the Lehigh Portland cement district, at Northampton, Pa. + +_Testing Machines._--The various structural forms into which concrete +and reinforced concrete may be assembled for use in public-building +construction, are undergoing investigative tests as to their compressive +and tensile strength, resistance to shearing, modulus of elasticity, +coefficient of expansion, fire-resistive qualities, etc. Similar tests +are being conducted on building stone, clay products, and the structural +forms in which steel and iron are used for building construction. + +The compressive, tensile, and other large testing machines, for all +kinds of structural materials reaching the testing stations, are under +the general supervision of Richard L. Humphrey, M. Am. Soc. C. E. The +immediate direction of the physical tests on the larger testing machines +is in charge of Mr. H. H. Kaplan. + +Most of this testing apparatus, prior to 1909, was housed in buildings +loaned by the City of St. Louis, in Forest Park, St. Louis, Mo., and the +arrangement of these buildings, details of equipment, organization, and +methods of conducting the tests, are fully set forth in Bulletin No. 329 +of the U.S. Geological Survey. In brief, this equipment included +motor-driven, universal, four-screw testing machines, as follows: One +600,000-lb., vertical automatic, four-screw machine; one 200,000-lb., +automatic, four-screw machine; and one 200,000-lb. and one 100,000-lb. +machine of the same type, but with three screws. There are a number of +smaller machines of 50,000, 40,000, 10,000, and 2,000 lb., respectively. + +These machines are equipped so that all are available for making tensile +and compressive tests (Fig. 1, Plate XIII). The 600,000-lb. machine is +capable of testing columns up to 30-ft. lengths, and of making +transverse tests of beams up to 25-ft. span, and tension tests for +specimens up to 24 ft. in length. The smaller machines are capable of +making tension and compressive tests up to 4 ft. in length and +transverse beam tests up to 12 ft. span. In addition, there are ample +subsidiary apparatus, including concrete mixers with capacities of ½ and +1 cu. yd., five hollow concrete block machines, automatic sifting +machines, briquette moulds, storage tanks, etc. + +At the Atlantic City sub-station, there is also a 200,000-lb., +universal, four-screw testing machine, with miscellaneous equipment for +testing cement and moulding concrete, etc.; and at the Northampton +sub-station, there is a complete equipment of apparatus for cement +testing, capable of handling 10,000 bbl. per day. + +At the Pittsburg testing station, a 10,000,000-lb., vertical, +compression testing machine (Plate XIV), made by Tinius Olsen and +Company, is being erected for making a complete series of comparative +tests of various building stones of 2, 4, and 12-in. cube, of stone +prisms, 12 in. base and 24 in. high, of concrete and reinforced concrete +columns up to 65 ft. in height, and of brick piers and structural-steel +columns up to the the limits of the capacity and height of the machine. + + [Illustration: PLATE XIII. + + Fig. 1.--Testing Beam in 200,000-Lb. Machine. + + Fig. 2.--Fire Test of Panel.] + +This machine is a large hydraulic press, with an adjustable head, and a +weighing system for recording the loading developed by a triple-plunger +pump. It has a maximum clearance of 65 ft. between heads; the clearance +in the machine is a trifle more than 6 ft. between screws, and the heads +are 6 ft. square. + +The machine consists of a base containing the main cylinder, with a +sectional area of 2,000 sq. in., upon which rests the lower platform or +head, which is provided with a ball-and-socket bearing. The upper head +is adjustable over four vertical screws, 13½ in. in diameter and 72 ft. +2 in. long, by a system of gearing operating four nuts with +ball-bearings upon which the head rests. The shafting operating this +mechanism is connected with a variable-speed motor which actuates +the triple-plunger pump supplying the pressure to the main cylinder +(Fig. 4). + +The weighing device consists of a set of standard Olsen levers for +weighing one-eightieth of the total load on the main cylinder. This +reduction is effected through the medium of a piston and a diaphragm. +The main cylinder has a diameter of 50 in., and the smaller one, a +diameter of 5-9/16 in. The weighing beam is balanced by an +automatically-operated poise weight, and is provided with a device for +applying successive counterweights of 1,000,000 lb. each. Each division +on the dial is equivalent to a 100-lb. load, and smaller subdivisions +are made possible by an additional needle-beam. + +The power is applied by a 15-h.p., 220-volt, variable-speed motor +operating a triple-plunger pump, the gearing operating the upper head +being driven by the same motor. The extreme length of the main screws +necessitates splicing, which is accomplished as follows: + +In the center of the screws, at the splice, is a 3-in. threaded pin for +centering the upper and lower screws; this splice is strengthened by +sleeve nuts, split to facilitate their removal whenever it is necessary +to lower the upper head; after the head has passed the splice, the +sleeve nuts are replaced. + +In order to maintain a constant load, a needle-valve has been provided, +which, when the pump is operated at its lowest speed, will allow a +sufficient quantity of oil to flow into the main cylinder to equalize +whatever leakage there may be. The main cylinder has a vertical movement +of 24 in. The speed of the machine, for the purpose of adjustment, using +the gearing attached to the upper head, is 10 in. per min. The speed for +applying loads, controlled by the variable-speed motor driving the pump, +varies from a minimum of at least 1/60 in. per min. to a maximum of at +least ½ in. per min. The machine has a guaranteed accuracy of at least +one-third of 1%, for any load of more than 100,000 lb., up to its +capacity. + + [Illustration: Fig. 4. + + PLAN AND ELEVATION OF 10,000,000-LB. VERTICAL COMPRESSION + TESTING MACHINE] + +The castings for the base and the top head weigh approximately 48,000 +lb. each. Each main screw weighs more than 40,000 lb., the lower +platform weighing about 25,000 lb., and the main cylinder, 16,000 lb. +The top of the machine will be about 70 ft. above the top of the floor, +and the concrete foundation, upon which it rests, is about 8 ft. below +the floor line. + + [Illustration: PLATE XIV. + + 10,000,000-Lb. Testing Machine.] + +_Concrete and Cement Investigations._--The investigations relating to +concrete include the examination of the deposits of sand, gravel, stone, +etc., in the field, the collection of representative samples, and the +shipment of these samples to the laboratory for analysis and test. These +tests are conducted in connection with the investigation of cement +mortars, made from a typical Portland cement prepared by thoroughly +mixing a number of brands, each of which must meet the following +requirements: + + Specific gravity, not less than 3.10; + + Fineness, residue not to exceed 8% on No. 100, nor 25% on No. 200 + sieve; + + Time of setting: Initial set, not less than 30 min.; hard set, not + less than 1 hour, nor more than 10 hours. + + Tensile strength: Requirements applying to neat cement and to 1 part + cement with 3 parts standard sand: + + -------------------------------+--------------+---------- + | Neat cement. | 1:3 Mix. + Time specification. | Pounds. | Pounds. + -------------------------------+--------------+---------- + 24 hours in moist air | 175 | ... + 7 days (1 day in moist air, | 500 | 175 + 6 days in water) | | + 28 days (1 day in moist air, | 600 | 250 + 27 days in water) | | + -------------------------------+--------------+---------- + + Constancy of volume: Pats of neat cement, 3 in. in diameter, ½ in. + thick at center, tapering to a thin edge, shall be kept in moist air + for a period of 24 hours. A pat is kept in air at normal temperature + and observed at intervals for at least 28 days. Another pat is kept in + water maintained as near 70° Fahr. as practicable, and is observed at + intervals for at least 28 days. A third pat is exposed in an + atmosphere of steam above boiling water, in a loosely-closed vessel, + for 5 hours. These pats must remain firm and hard and show no signs of + distortion, checking, cracking, or disfiguration. + + The cement shall not contain more than 1.75% of anhydrous sulphuric + acid, nor more than 4% of magnesium oxide. + + A test of the neat cement must be made with each mortar series for + comparison of the quality of the typical Portland cement. + +The constituent materials are subjected to the following examination and +determinations, and, in addition, are analyzed to determine the +composition and character of the stone, sand, etc.: + + 1.--Mineralogical examination, + + 2.--Specific gravity, + + 3.--Weight, per cubic foot, + + 4.--Sifting (granulometric composition), + + 5.--Percentage of silt and character of same, + + 6.--Percentage of voids, + + 7.--Character of stone as to percentage of absorption, porosity, + permeability, compressive strength, and behavior under treatment. + +Physical tests are made to determine the tensile, compressive, and +transverse strengths of the cement and mortar test pieces, with various +preparations of cement and various percentages of material. Tests are +also made to determine porosity, permeability, volumetric changes in +setting, absorption, coefficient of expansion, effect of oil, etc. + +Investigation of concretes made from mixtures of typical Portland +cement, sand, stone, and gravel, includes tests on cylinders, prisms, +cubes, and other standard test pieces, with various proportions of +materials and at ages ranging from 30 to 360 days. Full-sized plain +concrete beams, moulded building blocks, reinforced concrete beams, +columns, floor slabs, arches, etc., are tested to determine the effect, +character, and amount of reinforcement, the effect of changes in volume, +size, and composition, and the effect of different methods of loading +and of supporting these pieces, etc. + +These investigations include detailed inquiry in the field and research +in the chemical and physical laboratories regarding the effects of +alkaline soils and waters on structures of concrete being built by the +Reclamation Service in the arid regions. It has been noted that on +certain of the Reclamation projects, notably on the Sun River Project, +near Great Falls, Mont., the Shoshone Project, near Cody, Wyo., and the +Carlsbad and Hondo Projects in the Pecos Valley, N. Mex., structures of +concrete, reinforced concrete, building stones, brick, and tile, show +evidence of disintegration. This is attributed to the effects of +alkaline waters or soils coming into contact with the structures, or to +the constituent materials used. In co-operation with the Reclamation +Service, samples of the waters, soils, and constituent materials, are +collected in the field, and are subjected to careful chemical +examination in the mineral laboratories at Pittsburg. + + [Illustration: PLATE XV. + + Fig. 1.--Characteristic Failures of Reinforced Concrete Beams. + + Fig. 2.--Arrangement of Static Load Test for Reinforced + Concrete Beams.] + +The cylinders used in the percolation tests are composed of typical +Portland cement mixed with sand, gravel, and broken stone of known +composition and behavior, and of cement mixed with sand, gravel, and +broken stone collected in the neighborhood of the Reclamation projects +under investigation. + + [Illustration: Fig. 5. + + CROSS-SECTION OF APPARATUS FOR HOLDING PERMEABILITY-TEST PIECES] + +It is also proposed to subject these test pieces, some made with water +of known purity, and others with alkaline water, to contact with +alkaline soils near the projects, and with soil of known composition +near the testing laboratories at Pittsburg. As these tests progress and +other lines of investigation are developed, the programme will be +extended, in the hope that the inquiry may develop methods of preparing +and mixing concrete and reinforced concrete which can be used in +alkaline soils without danger of disintegration. + +Investigations into the effect of salt water on cement mortars and +concretes, and the effect of electrolysis, are being conducted at +Atlantic City, N.J., where the test pieces may be immersed in deep sea +water for longer or shorter periods of time. + +At the Pittsburg laboratory a great amount of investigative work is done +for the purpose of determining the suitability and availability of +various structural materials submitted for use by the Government. While +primarily valuable only to the Government, the results of these tests +are of indirect value to all who are interested in the use of similar +materials. Among such investigations have been those relating to the +strength, elasticity, and chemical properties of wire rope for use in +the Canal Zone; investigations of the suitability and cementing value of +concrete, sand, stone, and pozzuolanic material found on the Isthmus; +investigations as to the relative resistance to corrosion of various +types of wire screens for use in the Canal Zone; into the suitability +for use, in concrete sea-wall construction, of sand and stone from the +vicinity of San Francisco; into the properties of reinforced concrete +floor slabs; routine tests of reinforcing metal, and of reinforced +concrete beams and columns, for the Supervising Architect of the +Treasury Department, etc. The results have been set forth in three +bulletins[9] which describe the methods of conducting these tests and +also tests on constituent materials of concrete and plain concrete +beams. In addition, there are in process of publication a number of +bulletins giving the results of tests on reinforced concrete beams, +columns, and floor slabs, concrete building blocks, etc. + +The Northampton laboratory was established because it is in the center +of the Lehigh cement district, and therefore available for the mill +sampling and testing of purchases of cement made by the Isthmian Canal +Commission; it is also available for tests of cement purchased in the +Lehigh district by the Supervising Architect and others. It is in a +building, the outer walls of which are of cement plaster applied over +metal lath nailed to studding. The partitions are of the same +construction, and the floors and roof are of concrete throughout. + +The inspection at the factories and the sampling of the cement are under +the immediate direction of the Commission; the testing is under the +direction of the U.S. Geological Survey. A large force of employees is +required, in view of the magnitude of the work, which includes the daily +testing of consignments ranging from 5,000 to 10,000 bbl., sampled in +lots of 100 bbl., which is equivalent to from 50 to 100 samples tested +per day. + +The cement to be sampled is taken from the storage bins and kept under +seal by the chief inspector pending the results of the test. The +quantity of cement sampled is sufficient for the tests required under +the specifications of the Isthmian Canal Commission, as well as for +preliminary tests made by the cement company, and check tests made at +the Geological Survey laboratory, at Pittsburg. + +The tests specified by the Commission include determination of specific +gravity, fineness of grinding, time of setting, soundness, tensile +strength (with three parts of standard quartz sand for 7 and 28 days, +respectively), and determination of sulphur anhydride (SO_{3}), and +magnesia (MgO). + +The briquette-making and testing room is fitted with a mixing table, +moist closet, briquette-storage tanks, and testing machines. The mixing +table has a concrete top, in which is set plate glass, 18 in. square and +1 in. thick. Underneath the table are shelves for moulds, glass plates, +etc. + +The moist closet, 5 ft. high, 3 ft. 10 in. wide, and 1 ft. 8 in. deep, +is divided into two compartments by a vertical partition, and each +compartment is fitted with cleats for supporting thirteen tiers of glass +plates. On each pair of cleats, in each compartment, can be placed four +glass plates, each plate containing a 4-gang mould, making storage for +416 briquettes. With the exception of the doors, which are of wood lined +with copper, the closet is of 1:1 cement mortar, poured monolithic, even +to the cleats for supporting the glass plates. + +The immersion tanks, of the same mortar, are in tiers of three, +supported by a steel structure. They are 6¼ ft. long, 2¼ ft. wide, and 6 +in. deep, and 2,000 briquettes can be stored in each tank. The overflow +from the top tank wastes into the second, which, in turn, wastes into +the third. Water is kept running constantly. + +The briquette-testing machine is a Fairbanks shot machine with a +capacity of 2,000 lb., and is regulated to apply the load at the rate of +600 lb. per min. Twenty-four 4-gang moulds, of the type recommended by +the Special Committee on Uniform Tests of Cement, of the American +Society of Civil Engineers, are used. + +The room for noting time of set and soundness is fitted with a mixing +table similar to that in the briquette-making room. The Vicat apparatus +is used for determining the normal consistency, and the Gilmore +apparatus for the time of setting. While setting, the soundness pats are +stored in galvanized-iron pans having about 1 in. of water in the +bottom, and covered with dampened felt or burlap. The pats rest on a +rack slightly above the water and well below the felt. + +For specific gravity tests, the Le Chatelier bottles are used. A pan, in +which five bottles can be immersed at one time, is used for maintaining +the benzine at a constant temperature. The samples are weighed on a pair +of Troemner’s No. 7 scales. + +The fineness room is fitted with tables, two sets of standard No. 100 +and No. 200 sieves, and two Troemner’s No. 7 scales similar to those +used for the specific gravity tests. + +The storage room is fitted with shelves for the storage of samples being +held for 28-day tests. + +The mould-cleaning room contains tables for cleaning moulds, and racks +for air pats. + +An effort is made to keep all the rooms at a temperature of 70° Fahr., +and, with this in view, a Bristol recording thermometer is placed in the +briquette-room. Two wet-and-dry bulb hygrometers are used to determine +the moisture in the air. + +Samples are taken from the conveyor which carries the cement to the +storage bins, at the approximate rate of one sample for each 100 bbl. +After each 4,000-bbl. bin has been filled, it is sealed until all tests +have been made, when, if these have been satisfactory, it is released +for shipment. + +The samples are taken in cans, 9 in. high and 7½ in. in diameter. These +cans are delivered in the preparation room where the contents are mixed +and passed through a No. 20 sieve. Separate samples are then weighed out +for mortar briquettes, for soundness pats, and for the specific-gravity +and fineness tests. These are placed in smaller cans and a quantity +sufficient for a re-test is held in the storage room awaiting the +results of all the tests. + +The sample for briquettes is mixed with three parts standard crushed +quartz, and then taken to the briquette-making room, where eight +briquettes are made, four for 7-day and four for 28-day tests. These are +placed in the moist closet in damp air for 24 hours, then removed from +the moulds, and placed in water for the remainder of the test period. At +the proper time they are taken from the immersion tank and broken. + +From the sample for soundness, four pats are made. The time of setting +is determined on one of these pats. They are placed in the pan +previously described, for 24 hours, then one is placed in running water +and one in air for 28 days. The others are treated in the boiler, one in +boiling water for 3 hours and one in steam at atmospheric pressure for 5 +hours. + +The sample taken for specific gravity and fineness is dried in the oven +at 100° cent. in order to drive off moisture. Two samples are then +carefully weighed out, 50 grammes for fineness and 64 grammes for +specific gravity, and the determinations are made. As soon as anything +unsatisfactory develops, a re-test is made. If, however, the cement +satisfies all requirements, a report sheet containing all the data for a +bin, is made out, and the cement is ready for shipment. From every fifth +bin, special neat and mortar briquettes are made, which are intended for +tests at ages up to ten years. + +_Salt-Water Laboratory._--The laboratory at Atlantic City, for +conducting investigations into the effects of salt water on concrete and +reinforced concrete, is situated so that water more than 25 ft. deep is +available for immersion tests of the setting and deterioration of such +materials. + +Through the courtesy of the municipality of Atlantic City, Young’s +cottage, on old Young’s Pier, has been turned over, at a nominal rental, +to the Geological Survey for the conduct of these tests. The laboratory +building is about 700 ft. from the boardwalk, and occupies a space about +100 by 45 ft. It is one story high, of frame-cottage construction, and +stands on wooden piles at one side of the pier proper and about 20 ft. +above the water, which is about 19 ft. deep at this point. Fresh running +water, gas, electric light, and electric power are supplied to the +building (Fig. 6). + +In this laboratory investigations will be made of the cause of the +failure and disintegration of cement and concrete subjected to the +action of sea water. Tests are conducted so as to approach, as nearly as +possible, the actual conditions found in concrete construction along the +sea coast. All sea-water tests are made in the ocean, some will probably +be paralleled by ocean-water laboratory tests and all by fresh-water +comparative tests. + +Cements, in the form of pats, briquettes, cubes, cylinders, and in a +loose ground state, and also mortars and concretes in cube, cylinder, +and slab form, are subjected to sea water. + +The general plan for the investigations is as follows: + +1.--Determination of the failing elements and the nature of the failure; + +2.--Determination of the value of the theories advanced at the present +time; and, + +3.--Determination of a method of eliminating or chemically recombining +the injurious elements. + +Preliminary tests are in progress, including a study of the effect of +salt water on mortars and concretes of various mixtures and ages. The +proportions of these mixtures and the methods of mixing will be varied +from time to time, as suggested by the progress of the tests. + +_Fire-Proofing Tests._--Tests of the fire-proofing and fire-resistive +properties of various structural materials are carried on in the +laboratories in Building No. 10, at Pittsburg, and in co-operation with +the Board or Fire Underwriters at its Chicago laboratory (Fig. 2, Plate +XIII). These tests include three essential classes of material: (_a_), +clay products, protective coverings representative of numerous varieties +of brick and fire-proofing tiles, including those on the market and +those especially manufactured for these tests in the laboratory at +Pittsburg; (_b_), characteristic granites of New England, with +subsequent tests of the various building stones found throughout the +United States; and (_c_), cement and concrete covering material, +building blocks, and concrete reinforced by steel bars embedded at +different depths for the purpose of studying the effect of expansion on +the protective covering. + +In co-operation with the physical laboratory, these tests include a +study of the relative rates of conductivity of cement mortars and +concretes. By embedding thermo-couples in cylinders composed of the +materials under test, obtaining a given temperature by an electric coil, +and noting the time required to raise the temperature at the various +embedded couples to a given degree, the rate of conductivity may be +determined. Other tests include those in muffles to determine the rate +of expansion and the effect of heat and compressive stresses combined on +the compressive strength of the various structural materials. The +methods of making the panel tests, and the equipment used, are described +and illustrated in Bulletin No. 329, and the results of the tests have +been published in detail.[10] + +_Building Stones Investigations._--The field investigations of building +stones are conducted by Mr. E. F. Burchard, and include the examination +of the various deposits found throughout the United States. A study of +the granites of New England has been commenced, which includes the +collection of type specimens of fine, medium, and coarse-grained +granites, and of dark, medium, and light-gray or white granites. A +comparative series of these granites, consisting of prisms and cubes of +4 and 2 in., respectively, has been prepared. + + [Illustration: Fig. 6. + + PLAN OF LABORATORY FOR SALT-WATER TESTS AT ATLANTIC CITY, N.J.] + +The standard adopted for compressive test pieces in the 10,000,000-lb. +machine is a prism, having a base of 12 in. and being 24 in. high. The +tests include not only those for compression or crushing strength, but +also those for resistance to compressive strains of the prisms and +cubes, when raised to high temperatures in muffles or kilns; resistance +to weathering, freezing, and thawing; porosity; fire-resisting +qualities, etc. + +In collecting field samples, special attention is paid to the occurrence +of the stone, extent of the deposit, strike, dip, etc., and specimens +are procured having their faces cut with reference to the bedding +planes, in order that compressive and weathering tests may be made, not +only in relation to these planes but at those angles thereto in which +the material is most frequently used commercially. Attention is also +paid to the results of blasting, in its relation to compressive strains, +as blasting is believed to have a material effect on stones, especially +on those which may occur in the foundations of great masonry dams, and +type specimens of stone quarried by channeling, as well as by blasting, +are collected and tested. + +_Clay and Clay Products Investigations._--These investigations are in +charge of Mr. A. V. Bleininger, and include the study of the occurrence +of clay beds in various parts of the United States, and the adaptability +of each clay to the manufacture of the various clay products. + +Experiments on grinding, drying, and burning the materials are conducted +at the Pittsburg testing station, to ascertain the most favorable +conditions for preparing and burning each clay, and to determine the +most suitable economic use to which it may be put, such as the +manufacture of building or paving bricks, architectural tiles, sewer +tiles, etc. + +The laboratory is equipped with various grinding and drying devices, +muffles, kilns, and apparatus for chemical investigations, physical +tests, and the manufacture and subsequent investigative tests of clay +products. + +This section occupies the east end of Building No. 10, and rooms on the +first and second floors have been allotted for this work. In addition, a +brick structure, 46 by 30 ft., provided with a 60-ft. iron stack, has +been erected for housing the necessary kilns and furnaces. + + [Illustration: PLATE XVI. + + Fig. 1.--Brick Machine and Universal Cutter. + + Fig. 2.--House-Heating Boilers, Building No. 21.] + +On the ground floor of Building No. 10, adjoining the cement and +concrete section, is a storage room for raw materials and product under +investigation. Adjoining this room, and connecting with it by wide +doors, is the grinding room, containing a 5-ft. wet pan, with 2,000-lb. +rollers, to be used for both dry and wet grinding. Later, a heavy dry +pan is to be installed. With these machines, even the hardest material +can be easily disintegrated and prepared. In this room there is also a +jaw crusher for reducing smaller quantities of very hard material, as +well as a 30 by 16-in. iron ball mill, for fine grinding. These machines +are belted to a line shaft along the wall across the building. Ample +sink drainage is provided for flushing and cleaning the wet pan, when +changing from one clay to another. + +A large room adjoining is for the operation of all moulding and shaping +machines, representing the usual commercial processes. At present these +include an auger machine, with a rotary universal brick and tile cutter, +Fig. 1, Plate XVI, and a set of brick and special dies, a hand repress +for paving brick, and a hand screw press for dry pressing. The brick +machine is operated from the main shaft which crosses the building in +this room and is driven from a 50-h.p. motor. It is possible thus to +study the power consumption under different loads and with different +clays, as well as with varying degrees of water content in the clay. As +the needs of the work demand it, other types of machines are to be +installed. For special tests in which pressure is an important factor it +is intended to fit up one of the compression testing machines of the +cement section with the necessary dies, thus enabling the pressing to be +carried on under known pressures. Crushing, transverse, and other tests +of clay products are made on the testing machines of the cement and +concrete laboratories. + +Outside of the building, in a lean-to, there is a double-chamber rattler +for the testing of paving brick according to the specifications of the +National Brick Manufacturers’ Association. + +In the smaller room adjoining the machine laboratory there are two small +wet-grinding ball mills, of two and four jars, respectively, and also a +9-leaf laboratory filter press. + +The remaining room on the first floor is devoted to the drying of clays +and clay wares. The equipment consists of a large sheet-iron drying oven +of special construction, which permits of close regulation of the +temperature (Fig. 7). It is heated by gas burners, and is used for the +preliminary heat treatment of raw clays, in connection with the study of +the drying problems of certain raw materials. It is intended to work +with temperatures as high as 250° cent. + +Another drying closet, heated by steam coils (Fig. 8), intended for +drying various clay products, has been designed with special reference +to the exact regulation of the temperature, humidity, and velocity of +the air flowing through it. Both dryers connect by flues with an iron +stack outside the building. This stack is provided with a suction fan, +driven by a belt from an electric motor. + +On the second floor are the chemical, physical, and research +laboratories, dealing with the precise manipulations of the tests and +investigations. + +The chemical laboratory is fully equipped with the necessary apparatus +for carrying on special chemical research in silicate chemistry, +including electrical resistance furnaces, shaking devices, etc. It is +not the intention to do routine work in this laboratory. The office +adjoins this laboratory, and near it is the physical laboratory, devoted +to the study of the structure of raw materials. The latter contains +Nobel and Schoene elutriators, together with viscosimeters of the flow +and the Coulomb and Clark electrical types, sieves, voluminometers, +colorimeters, vernier shrinkage gauges, micrometers, microscopes, and +the necessary balances. + +The room across the hall is devoted to the study of the specific +gravity, absorption, porosity, permeability, hardness, translucency, +etc., of burnt-clay products, all the necessary apparatus being +provided. In the two remaining rooms, intended for research work, +special apparatus adapted to the particular investigation may be set up. +All the rooms are piped for water, gas, compressed air, steam, and +drainage, and wired for light and power. + +In the kiln house there is a test kiln adapted for solid fuel and gas. +It is of the down-draft type, with an available burning space of about 8 +cu. ft. (Fig. 9). For heavier ware and the study of the fire behavior of +clay products under conditions approaching those of practice, a round +down-draft kiln, with an inside diameter of 6 ft., is installed. About +13 ft. above the floor level, and supported by iron beams, there is a +flue parallel to the long side of the structure. This flue conducts the +gases of the kilns to the stack, which is symmetrically located with +reference to the kiln house. Natural gas is the principal fuel. In +addition to these kilns, a small muffle furnace, fired with petroleum, +is provided for the determination of melting points, and an electric +carbon resistance furnace, with an aluminum muffle for high-temperature +work. For crucible-fusion work, a gas-fired pot furnace is installed. + + [Illustration: Fig. 7. + + CLAY-DRYING OVEN] + +Along the north wall, bins are provided for the storage of fuel, clay, +sand, and other kiln supplies. There are two floor drainage sinks, and +electric current, steam, water, and compressed air, are provided. + + [Illustration: Fig. 8. + + DRYING CLOSETS FOR CERAMICS] + +_Results of the Work._--More than 39,300 separate test pieces have been +made at the structural-materials testing laboratory. In connection with +the study of these, 86,000 tests and nearly 14,000 chemical analyses +have been made. Of these tests more than 13,600 have been of the +constituent materials of concrete, including tensile tests of cement +briquettes, compression tests of cylinders and cubes, and transverse +tests of various specimens. + +Nearly 1,200 beams of concrete or reinforced concrete, each 13 ft. long +and 8 by 11 in. in cross-section, have been made, and, in connection +with the investigation of the behavior of these beams, nearly 3,000 +tests have been made. Nearly 900 of these beams, probably more than +double the entire number made in other laboratories in the United +States, during a period of more than 15 years, have been tested. + +In the section of building blocks, 2,200 blocks have been tested, +including, with auxiliary pieces, more than 4,500 tests; also, more than +900 pieces of concrete have been tested for permeability and shear. The +physical tests have numbered 14,000; tests of steel for reinforcement, +3,800; and 550 tests to determine fire-resistive qualities of various +building materials, have been made on 30 special panels, and on +miscellaneous pieces. + + [Illustration: Fig. 9. + + DOWN-DRAFT KILN] + +The tests of the permeability of cement mortars and concretes, and of +water-proofing and damp-proofing materials, have numbered 3,470. + +The results of the work of the Structural Materials Division have +already appeared in preliminary bulletins, as follows: No. 324, “San +Francisco Earthquake and Fire of April 18, 1906, and Their Effects on +Structures and Structural Materials”; No. 329, “Organization, Equipment, +and Operation of the Structural-Materials Testing Laboratories at St. +Louis, Mo.”; No. 331, “Portland Cement Mortars and Their Constituent +Materials” (based on nearly 25,000 tests); No. 344, “Strength of +Concrete Beams” (based on tests of 108 beams); No. 370, “Fire-Resistive +Properties of Various Building Materials”; No. 387, “The Colloid Matter +of Clay and its Measurements.” A bulletin on the results of tests of +reinforced concrete beams, one on the manufacture and chemistry of lime, +and one on drying tests of brick, are in course of publication. + + +FUEL INVESTIGATIONS. + +The scope of the fuel investigations has been planned to conform to the +provisions of the Act of Congress which provides for analyzing and +testing coals, lignites, and other mineral fuel substances belonging to +the United States, or for the use of the United States Government, and +examinations for the purpose of increasing the general efficiency or +available supply of the fuel resources in the United States. + +In conformity with this plan, the investigations inaugurated at St. +Louis had for their initial object the analyzing and testing of the +coals of the United States, using in this work samples of from 1 to 3 +carloads, collected with great care from typical localities in the more +important coal fields of the country, with a view to determining the +relative values of those different fuels. In the work at Norfolk, during +1907, this purpose was modified to the extent of keeping in view +relative fuel efficiencies for naval purposes. The tests at Denver have +been on coal from Government land or from land contiguous thereto, and +are conducted solely with a view to perfecting methods of coking this +coal by prior washing and by manipulation in the process of coking. + +Three general lines of inquiry are embodied in the plan of investigation +undertaken and contemplated by the Technologic Branch, after conference +and with the advice and approval of the Advisory Board: 1. The +ascertainment of the best mode of utilizing any fuel deposit owned or to +be used by the Government, or the fuel of any extensive deposit as a +whole, by conducting a more thorough investigation into its combustion +under steam boilers, conversion into producer gas, or into coke, +briquettes, etc. 2. The prevention of waste, through the study of the +possibility of improvement in the methods of mining, shipping, +utilizing, etc. 3. The inspection and analysis of coal and lignite +purchased under specification for the use of the Government, to +ascertain its heating value, ash, contained moisture, etc. + +The first general line of work concerns the investigation and testing of +the fuel resources of the United States, and especially those belonging +to the Federal Government, to determine a more efficient and more +economical method of utilizing the same. This work has developed along +the following lines: + +The collection of representative samples for chemical analysis, and +calorimeter tests by a corps of skilled mine samplers, from the mines +selected as typical of extensive deposits of coal in a given field or +from a given bed of coal; and the collection from the same mines of +larger samples of from 1 to 3 carloads, shipped to the testing station +for tests in boiler furnaces, gas producers, etc., as a check on the +analysis and calorimeter tests; + +The testing of each coal received to determine the most efficient and +least wasteful method of use in different furnaces suitable for public +buildings or power plants or ships of the Government; + +The testing of other portions of the same shipment of coal in the gas +producer, for continuous runs during periods of a few days up to several +weeks, in order to determine the availability of this fuel for use in +such producers, and the best method of handling it, to determine the +conditions requisite to produce the largest amount of high-grade gas +available for power purposes; + +The testing of another portion of the same coal in a briquette machine +at different pressures and with different percentages and kinds of +binder, in order to determine the feasibility of briquetting the slack +or fine coal. Combustion tests are then made of these briquettes, to +determine the conditions under which they may be burned advantageously; + +Demonstrations, on a commercial scale, of the possibility of producing +briquettes from American lignites, and the relative value of these for +purposes of combustion as compared with the run-of-mine coal from which +the briquettes are made; + +The finding of cheaper binders for use in briquetting friable coals not +suited for coking purposes; + +Investigations into the distribution, chemical composition, and +calorific value of the peat deposits available in those portions of the +United States where coal is not found, and the preparation of such peat +for combustion, by drying or briquetting, to render it useful as a local +substitute for coal; + +Investigations into the character of the various petroleums found +throughout the United States, with a view to determining their calorific +value, chemical composition, and the various methods whereby they may be +made most economically available for more efficient use as power +producers, through the various methods of combustion; + +Investigations and tests into the relative efficiency, as power +producers in internal-combustion engines, of the heavier distillates of +petroleum, as well as of kerosene and gasoline, in order to ascertain +the commercial value and relative efficiency of each product in the +various types of engines; + +Investigations into the most efficient methods of utilizing the various +coals available throughout the United States for heating small public +buildings, army posts, etc., in order that these coals may be used more +economically than at present; + +Investigative studies into the processes of combustion within boiler +furnaces and gas producers to ascertain the temperatures at which the +most complete combustion of the gases takes place, and the means whereby +such temperatures may be produced and maintained, thus diminishing the +loss of values up the smokestack and the amount of smoke produced; + +Investigations and tests into the possibilities of coking coals which +have hitherto been classed as non-coking, and the making of comparative +tests of all coals found in the United States, especially those from the +public lands of the West; + +Investigations, by means of washing in suitable machines, to determine +the possibility of improving the quality of American coals for various +methods of combustion, and with a view to making them more available for +the production of coke of high-grade metallurgical value, as free as +possible from sulphur and other injurious substances. + +At each stage of the process of testing, samples of the coal have been +forwarded to the chemical laboratory for analyses; combustion +temperatures have been measured; and samples of gas collected from +various parts of the combustion chambers of the gas producers and boiler +furnaces have been analyzed, in order that a study of these data may +throw such light on the processes of combustion and indicate such +necessary changes in the apparatus, as might result in larger economies +in the use of coal. + +The second line of investigation concerns the methods of mining and +preparing coal for the market, and the collection of mine samples of +coal, oil, etc., for analysis and testing. It is well known that, under +present methods of mining, from 10 to 75% of any given deposit of coal +is left underground as props and supports, or as low-grade material, or +in overlying beds broken up through mining the lower bed first. An +average of 50% of the coal is thus wasted or rendered valueless, as it +cannot be removed subsequently because of the caving or falling in of +the roofs of abandoned galleries and the breaking up of the adjoining +overlying beds, including coal, floor, and roof. + +The investigations into waste in mining and the testing of the waste, +bone, and slack coal in gas producers, as briquettes, etc., have, for +their purpose, the prevention of this form of waste by demonstrating +that these materials, now wasted, may be used profitably, by means of +gas producers and engines, for power purposes. + +The third general line of investigation concerns the inspection and +sampling of fuel delivered to the Government under purchase contracts, +and the analyzing and testing of the samples collected, to determine +their heating value and the extent to which they may or may not comply +with the specifications under which they are purchased. The coal +delivered at the public buildings in the District of Columbia is sampled +by special representatives of the Technologic Branch of the Survey. The +taking of similar samples at public buildings and posts throughout the +United States, and the shipment of the samples in hermetically sealed +cans or jars to the chemical laboratory at Washington, is for the most +part looked after by special officers or employees at each place. These +purchases are made, to an increasing extent, under specifications which +provide premiums for coal delivered in excess of standards, and +penalties for deliveries below standards fixed in the specifications. +The standard for bituminous coals is based mainly on the heat units, +ash, and sulphur, while that for anthracite coal is based mainly on the +percentage of ash and the heat units. + +In connection with all these lines of fuel testing, certain research +work, both chemical and physical, is carried on to determine the true +composition and properties of the different varieties of coal, the +changes in the transformation from peat to lignite, from lignite to +bituminous coal, and from bituminous to anthracite coal, and the +chemical and physical processes in combustion. Experiments are conducted +concerning the destructive distillation of fuels; the by-products of +coking processes; the spontaneous combustion of coal; the storage of +coal, and the loss in value in various methods of storing; and kindred +questions, such as the weathering of coal. These experiments may yield +valuable results through careful chemical research work supplemented by +equally careful observations in the field. + +_Inspection and Mine Sampling._--In the Geological Survey Building, at +Washington, coal purchased for Government use on a guaranteed-analysis +or heat-value basis, is inspected and sampled. + +Some of the employees on this work are constantly at the mines taking +samples, or at public works inspecting coal for Government use, while +others are stationed at Washington to look after the deliveries of coal +to the many public buildings, and to collect and prepare samples taken +from these deliveries for analysis, as well as to prepare samples +received from public works and buildings in other parts of the country. + + [Illustration: Fig. 10. + + COAL-SAMPLING ROOM, GEOLOGICAL SURVEY, WASHINGTON, D.C.] + +The preparation of these samples is carried on in a room in the basement +of the building, where special machinery has been installed for this +work. Fig. 10 shows a plan of this room and the arrangement of the +sampling and crushing machinery. + +The crushing of the coal produces great quantities of objectionable +dust, and to prevent this dust from giving trouble outside the sampling +room, the wooden partitions on three sides of the room (the fourth side +being a masonry wall) are completely covered on the outside with +galvanized sheet iron. The only openings to the room are two doors, +which are likewise covered with sheet iron, and provided with broad +flanges of the same material, in order to seal effectually the openings +when the doors are shut. Fresh air is drawn into the room by a fan, +through a pipe leading to the outer air. A dust-collecting system which +carries the coal dust and spent air from the room, consists of an +arrangement of 8-in. and 12-in. pipes leading from hoods, placed over +the crushing machines, to the main furnace stack of the building. The +draft in this stack draws all the dust from the crushers directly +through the hoods to the main pipe, where most of it is deposited. + +The equipment of the sampling room consists of one motor-driven, baby +hammer crusher, which has a capacity of about 1 ton per hour and crushes +to a fineness of ¼-in. mesh; one adjustable chipmunk jaw crusher, for 5- +and 10-lb. samples; one set of 4½ by 7½-in. rolls, crushing to 60 mesh, +for small samples; one large bucking board, and several different sizes +of riffle samplers for reducing samples to small quantities. The small +crushers are belted to a shaft driven by a separate motor from that +driving the baby crusher. + +In conducting the inspection of departmental purchases of coal in +Washington, the office is notified whenever a delivery of coal is to be +made at one of the buildings, and an inspector is sent, who remains +during the unloading of the coal. He is provided with galvanized-iron +buckets having lids and locks; each bucket holds about 60 lb. of coal. +In these buckets he puts small quantities of the coal taken from every +portion of the delivery, and when the delivery has been completed, he +locks the buckets and notifies the office to send a wagon for them. The +buckets are numbered consecutively, and the inspector makes a record of +these numbers, the date, point of delivery, quality of coal delivered, +etc. The buckets are also tagged to prevent error. He then reports to +the office in person, or by telephone, for assignment to another point +in the city. All the samples are delivered to the crushing room in the +basement of the Survey Building, to be prepared for analysis.[11] + +Samples taken from coal delivered to points outside of Washington are +taken by representatives of the department for which the coal is being +purchased, according to instructions furnished them, and, from time to +time, the regular inspectors are sent to see that these instructions are +being complied with. These samples are crushed by hand, reduced to about +2 lb. at the point where they are taken, and sent to Washington, in +proper air-tight containers, by mail or express, accompanied by +appropriate descriptions. + +Each sample is entered in the sample record book when received, and is +given a serial number. For each contract a card is provided giving +information relative to the contract. On this card is also entered the +serial number of each sample of coal delivered under that contract. + +After the samples are recorded, they are sent to the crushing room, +where they are reduced to the proper bulk and fineness for analysis. +They are then sent, in rubber-stoppered bottles, accompanied by blank +analysis report cards and card receipts, one for each sample, showing +the serial numbers, to the fuel laboratory for analysis. The receipt +card for each sample is signed and returned to the inspection office, +and when the analysis has been made, the analysis report card showing +the result is returned. This result is entered at once on the contract +card, and when all analyses have been received, covering the entire +delivery of coal, the average quality is calculated, and the results are +reported to the proper department. + +The matter of supplying the Pittsburg plant with fuel for test purposes +is also carried on from the Washington office. Preliminary to a series +of investigations, the kinds and amounts of coal required are decided +on, and the localities from which these coals are to be obtained are +determined. Negotiations are then opened with the mine owners, who, in +most cases, generously donate the coal. When the preliminaries have been +arranged, an inspector is sent to the mine to supervise the loading and +shipment of the coal. This inspector enters the mine and takes, for +chemical analysis, small mine samples which are sent to the laboratory +at Pittsburg in metal cans by mail, accompanied by proper identification +cards. The results of the analysis are furnished to the experts in +charge at the testing plant, for their information and guidance in the +investigations for which the coal was shipped. + +All samples for testing purposes are designated consecutively in the +order of shipment, “Pittsburg No. 1,” “Pittsburg No. 2,” etc. A complete +record of all shipments is kept on card forms at the Pittsburg plant, +and a duplicate set of these is on file in the inspection office at +Washington. + +_Analysis of Fuels._--The routine analyses of fuel used in the +combustion tests at Pittsburg, and of the gases resulting from +combustion or from explosions in the testing galleries, or sampled in +the mines, are made in Building No. 21.[12] A small laboratory is also +maintained on the second floor of the south end of Building No. 13, for +analyses of gases resulting from combustion in the producer-gas plant, +and from explosions in Galleries Nos. 1 and 2, etc. From four to six +chemists are continually employed in this laboratory (in 8-hour shifts), +during prolonged gas-producer tests, and three chemists are also +employed in analyzing gases relating to mine explosions. + +In addition to these gas analyses, there are also made in the main +laboratory, analyses and calorific tests of all coal samples collected +by the Geological Survey in connection with its land-classification work +on the coal lands of the Western States. Routine analyses of mine, car, +and furnace samples of fuels for testing, before and after washing and +briquetting, before coking and the resultant coke, and extraction +analyses of binders for briquettes, etc., are also made in this +laboratory. + +The fuel-testing laboratory at Washington is equipped with three Mahler +bomb calorimeters and the necessary balances and chemical equipment +required in the proximate analysis of coal. More than 650 deliveries of +coal are sampled each month for tests, representing 50,000 tons +purchased per month, besides daily deliveries, on ship-board, of 550,000 +tons of coal for the Panama Railroad. The data obtained by these tests +furnish the basis for payment. The tests cover deliveries of coal to the +forty odd bureaus, and to the District Municipal buildings in +Washington; to the arsenals at Watertown, Mass., Frankford, Pa., and +Rock Island, Ill.; and to a number of navy yards, through the Bureau of +Yards and Docks; to military posts in various parts of the country; for +the Quartermaster-General’s Department; to the Reclamation Service; to +Indian Agencies and Soldiers’ Homes; to several lighthouse districts; +and to the superintendents of the various public buildings throughout +the United States, through the Treasury Department; etc. During 1909, +the average rate of reporting fuel samples was 540 per month, requiring, +on an average, six determinations per sample, or about 3,240 +determinations per month. + +_Fuel-Research Laboratories._--Smaller laboratories, occupying, on the +average, three rooms each, are located in Building No. 21. One is used +for chemical investigations and calorific tests of petroleum collected +from the various oil fields of the United States; another is used for +investigations relative to the extraction of coal and the rapidity of +oxidization of coals by standard solutions of oxidizing agents; and +another is occupied with investigations into the destructive +distillation of coal. The researches under way show the wide variation +in chemical composition and calorific value of the various crude oils, +indicate the possibility of the extraction of coal constituents by +solvents, and point to important results relative to the equilibrium of +gases at high temperatures in furnaces and gas producers. The +investigations also bear directly on the coking processes, especially +the by-product process, as showing the varying proportion of each of the +volatile products derivable from types of coals occurring in the various +coal fields of the United States, the time and temperature at which +these distillates are given off, the variation in quality and quantity +of the products, according to the conditions of temperature, and, in +addition, explain the deterioration of coals in storage, etc. + + [Illustration: Fig. 11. + + PLAN OF CONSTRUCTION DETAILS OF METAL HOOD] + +At the Washington office, microscopic investigations into the life +history of coal, lignite, and peat are being conducted. These +investigations have already progressed far enough to admit of the +identification of some of the botanical constituents of the older peats +and the younger lignites, and it is believed that the origin of the +older lignites, and even of some of the more recent bituminous coals, +may be developed through this examination. + +In the chemical laboratories, in Building No. 21, the hoods (Figs. 11 +and 12) are of iron, with a brick pan underneath. They are supported on +iron pipes, as are most of the other fixtures in the laboratories in +this building. The hood proper is of japanned, pressed-iron plate, No. +22 gauge, the same material being used for the boxes, slides, and bottom +surrounding the hood. The sash is hung on red copper pulleys, and the +corners of the hood are reinforced with pressed, japanned, riveted plate +to which the ventilating pipe is riveted. + + [Illustration: Fig. 12. + + ELEVATION OF CONSTRUCTION DETAILS OF METAL HOOD] + +There is some variety in the cupboards and tables provided in the +various laboratories, but, in general, they follow the design shown in +Fig. 13. The table tops, 12 ft. long, are of clear maple in full-length +pieces, ⅞ in. thick and 2⅝ in. wide, laid on edge and drilled at +18-in. intervals for bolts. These pieces are glued and drawn together by +the bolts, the heads of which are countersunk. The tops, planed off, +sanded, and rounded, are supported on pipe legs and frames of 1¼ by +1½-in. galvanized-iron pipe with screw flanges fitting to the floor and +top. Under the tops are drawers and above them re-agent shelves. Halfway +between the table top and the floor is a wire shelf of a frame-work of +No. 2 wire interlaced with No. 12 weave of ⅝-in. square mesh. + +Certain of the tables used in the laboratory are fitted with cupboards +beneath and with drawers, and, in place of re-agent stands, +porcelain-lined sinks are sunk into them. These tables follow, in +general style and construction, the re-agent tables. The tables used in +connection with calorimeter determinations are illustrated in Fig. 14. +The sinks provided throughout these laboratories are of standard +porcelain enamel, rolled rim, 18 by 13 in., with enameled back, over a +sink and drain board, 24 in. long on the left side, though there are +variations from this type in some instances. + +The plumbing includes separate lines of pipe to each hood and table; one +each for cold water, steam at from 5 to 10 lb. pressure, compressed air, +natural gas, and, in some cases, live steam at a pressure of 60 lb. + +On each table is an exposed drainage system of 2½-in. galvanized-iron +pipe, in the upper surface of which holes have been bored, through which +the various apparatus drain by means of flexible connections of glass or +rubber. These pipes and the sinks, etc., discharge into main drains, +hung to the ceiling of the floor beneath. These drains are of wood, +asphaltum coated, with an inside diameter ranging from 3 to 6 in., and +at the proper grades to secure free discharge. These wooden drain-pipes +are made in short lengths, strengthened by a spiral wrapping of metal +bands, and are tested to a pressure of 40 lb. per sq. in. Angles are +turned and branches connected in 4- and 6-in. square headers. + + [Illustration: Fig. 13. + + PLAN OF CONSTRUCTION DETAILS OF REAGENT TABLES BUILDING 21.] + + + [Illustration: Fig. 14. + + CONSTRUCTION DETAILS OF CALORIMETER TABLES] + +The entire building is ventilated by a force or blower fan in the +basement, and by an exhaust fan in the attic with sufficient capacity to +insure complete renewal of air in each laboratory once in 20 min. + +The blower fan is placed in the center of the building, on the ground +floor, and is 100 in. in diameter. Its capacity is about 30,000 cu. ft. +of air per min., and it forces the air, through a series of pipes, into +registers placed in each of the laboratories. + +The exhaust fan, in the center of the attic, is run at 550 rev. per +min., and has a capacity of 22,600 cu. ft. of air per min. It draws the +air from each of the rooms below, as well as from the hoods, through a +main pipe, 48 in. in diameter. + +_Steaming and Combustion Tests._--The investigations included under the +term, fuel efficiency, relate to the utilization of the various types of +fuels found in the coal and oil fields, and deal primarily with the +combustion of such fuels in gas producers, in the furnaces of steam +boilers, in locomotives, etc., and with the efficiency and utilization +of petroleum, kerosene, gasoline, etc., in internal-combustion engines. +This work is under the general direction of Mr. R. L. Fernald, and is +conducted principally in Buildings Nos. 13 (Plate XVII) and 21. + +For tests of combustion of fuels purchased by the Government, the +equipment consists of two Heine, water-tube boilers, each of 210 h.p., +set in Building No. 13. One of these boilers is equipped with a Jones +underfeed stoker, and is baffled in the regular way. At four points in +the setting, large pipes have been built into the brick wall, to permit +making observations on the temperature of the gas, and to take samples +of the gas for chemical analysis. + +The other boiler is set with a plain hand-fired grate. It is baffled to +give an extra passage for the gases (Fig. 15). Through the side of this +boiler, at the rear end, the gases from the long combustion chamber +(Plate XVIII) enter and take the same course as those from the +hand-fired grate. Both the hand-fired grate and the long combustion +chamber may be operated at the same time, but it is expected that +usually only one will be in operation. A forced-draft fan has been +installed at one side of the hand-fired boiler, to provide air pressure +when coal is being burned at high capacity. This fan is also connected +in such a way as to furnish air for the long combustion chamber when +desired. A more complete description of the boilers may be found in +Professional Paper No. 48, and Bulletin No. 325 of the U.S. Geological +Survey, in which the water-measuring apparatus is also described.[13] + +On account of the distance from Building No. 21 to the main group of +buildings, it was considered inadvisable to attempt to furnish steam +from Building No. 13 to Building No. 21, either for heating or power +purposes. In view, moreover, of the necessity of installing various +types and sizes of house-heating boilers, on account of tests to be made +thereon in connection with these investigations, it was decided to +install these boilers in the lower floor of Building No. 21, where they +could be utilized, not only in making the necessary tests, but in +furnishing heat and steam for the building and the chemical laboratories +therein. + + [Illustration: Fig. 15. + + SETTING FOR 210-HORSE POWER, HAND-FIRED BOILERS] + +In addition to the physical laboratory on the lower floor of Building +No. 21, and the house-heating boiler plant with the necessary coal +storage, there are rooms devoted to the storage of heavy supplies, +samples of fuels and oils, and miscellaneous commercial apparatus. One +room is occupied by the ventilating fan and one is used for the +necessary crushers, rolls, sizing screens, etc., required in connection +with the sampling of coal prior to analysis. + +The Quartermaster’s Department having expressed a wish that tests be +made of the heating value and efficiency of the various fuels offered +that Department, in connection with the heating of military posts +throughout the country, three house-heating boilers were procured which +represent, in a general way, the types and sizes used in a medium-sized +hospital or other similar building, and in smaller residences (Fig. 2, +Plate XVI). The larger apparatus is a horizontal return-tubular boiler, +60 in. in diameter, 16 ft. long, and having fifty-four 4-in. tubes.[14] + +In order to determine whether such a boiler may be operated under +heating conditions without making smoke, when burning various kinds of +coal, it has been installed in accordance with accepted ideas regarding +the prevention of smoke. A fire-brick arch extends over the entire grate +surface and past the bridge wall. A baffle wall has been built in the +combustion chamber, which compels the gases to pass downward and to +divide through two openings before they reach the boiler shell. +Provision has been made for the admission of air at the front of the +furnace, underneath the arch, and at the rear end of the bridge wall, +thus furnishing air both above and below the fire. It is not expected +that all coals can be burned without smoke in this furnace, but it is +desirable to determine under what conditions some kinds of coals may be +burned without objectionable smoke.[15] + +For sampling the gases in the smokebox of the horizontal return-tubular +boiler, a special flue-gas sampler was designed, in order to obtain a +composite sample of the gases escaping from the boiler. + +The other heaters are two cast-iron house-heating boilers. One can +supply 400 sq. ft. of radiation and the other about 4,000 sq. ft. They +were installed primarily for the purpose of testing coals to determine +their relative value when burned for heating purposes. They are piped to +a specially designed separator, and from this to a pressure-reducing +valve. Beyond this valve an orifice allows the steam to escape into the +regular heating mains. This arrangement makes it possible to maintain a +practically constant load on the boilers. + + [Illustration: PLATE XVIII. + + Fig. 1.--Long Combustion Chamber. + + Fig. 2.--Gas Sampling Apparatus, Long Combustion Chamber.] + +There is a fourth boiler, designed and built for testing purposes by the +Quartermaster’s Department. This is a tubular boiler designed on the +lines of a house-heating boiler, but for use as a calorimeter to +determine the relative heat value of different fuels reduced to the +basis of a standard cord of oak wood. + +A series of research tests on the processes of combustion is being +conducted in Building No. 13, by Mr. Henry Kreisinger. These tests are +being made chiefly in a long combustion chamber (Figs. 16 and 17, and +Figs. 1 and 2, Plate XVIII), which is fed with coal from a Murphy +mechanical stoker, and discharges the hot gases at the rear end of the +combustion chamber, into the hand-fired Heine boiler. The walls and roof +of this chamber are double; the inner wall is 9 in. thick, of +fire-brick; the outer one is 8 in. thick, and is faced with red pressed +brick. Between the walls of the sides there is a 2-in. air space, and +between them on the roof a 1-in. layer of asbestos paste is placed. The +inner walls and roof have three special slip-joints, to allow for +expansion. The floor is of concrete, protected by a 1½-in. layer of +asbestos board, which in turn is covered by a 3-in. layer of earth; on +top of this earth there is a 4-in. layer of fire-brick (not shown in the +drawings). + + [Illustration: Fig. 16. + + CROSS-SECTIONS OF CHAMBER AND OF FURNACE, LONG COMBUSTION CHAMBER] + +Inasmuch as one of the first problems to be attacked will be the +determination of the length of travel and the time required to complete +combustion in a flame in which the lines of stream flow are nearly +parallel, great care was taken to make the inner surfaces of the tunnel +smooth, and all corners and hollows are rounded out in the direction of +travel of the gases. + +Provision is made, by large peep-holes in the sides, and by smaller +sampling holes in the top, for observing the fuel bed at several points +and also the flame at 5-ft. intervals along the tunnel. Temperatures and +gas samples are taken simultaneously at a number of points through these +holes, so as to determine, if possible, the progress of combustion +(Fig. 1, Plate XVIII). + +About twenty thermo-couples are embedded in the walls, roof, and floor, +some within 1 in. of the inside edge of the tunnel walls, and some in +the red pressed brick near the outer surface, the object of which is to +procure data on heat conduction through well-built brick walls[16] (Fig. +2, Plate XVIII). + +In order to minimize the leakage of air through the brickwork, the +furnace and tunnel are kept as nearly as possible at atmospheric +pressure by the combined use of pressure and exhausting fans. +Nevertheless, the leakage is determined periodically as accurately as +possible. + +At first a number of tests were run to calibrate the apparatus as a +whole, all these preliminary tests being made on cheap, carefully +inspected, uniform screenings from the same seam of the same mine near +Pittsburg. Later tests will be run with other coals of various volatile +contents and various distillation properties. + +It is anticipated that the progress of the tests may suggest changes in +the construction or operation of this chamber. It is especially +contemplated that the section of the chamber may be narrowed down by +laying sand in the bottom and fire-brick thereon; also that baffle walls +may be built into various portions of it, and that cooling surfaces with +baffling may be introduced. In addition to variations in the tests, due +to changes in construction in the combustion chamber, there will be +variations in the fuels tested. Especial effort will be made to procure +fuels ranging in volatile content from 15 to 27 and to 40%, and those +high in tar and heavy hydro-carbons. It is also proposed to vary the +conditions of testing by burning at high rates, such as at 15, 20, and +30 lb. per ft. of grate surface, and even higher. Records will be kept +of the weight of coal fired and of each firing, of the weight of ash, +etc.; samples of coal and of ash will be taken for chemical and physical +analysis, as well as samples of the gas, and other essential data. These +records will be studied in detail. + + [Illustration: Fig. 17. + + LONGITUDINAL SECTIONS OF LONG COMBUSTION CHAMBER] + +A series of heat-transmission tests undertaken two years ago, is being +continued on the ground floor of Building No. 21, on modified apparatus +reconstructed in the light of the earlier experiments by Mr. W. T. Ray. +The purpose of the tests on this apparatus has been to determine some of +the laws controlling the rate of transmission of heat from a hot gas to +a liquid and _vice versa_, the two being on the opposite sides of a +metal tube. + +It appears that four factors determine the rate of heat impartation from +the gas to any small area of the metal[17]: + + [Footnote 17: The assumption is made that a metal tube free from scale + will remain almost as cool as the water; actual measurements with + thermo-couples have indicated the correctness of this assumption in + the majority of cases.] + + (1).--The temperature difference between the body of the gas and the + metal; + + (2).--The weight of the gas per cubic foot, which is proportional to + the number of molecules in any unit of volume; + + (3).--The bodily velocity of the motion of the gas parallel to any + small area under consideration; and (probably), + + (4).--The specific heat of the gas at constant pressure. + +The apparatus consists of an electric resistance furnace containing +coils of nickel wire, a small (interchangeable) multi-tubular boiler, +and a steam-jet apparatus for reducing the air pressure at the exit end, +so as to cause a flow of air through the boiler. A surface condenser was +attached to the boiler’s steam outlet, the condensed steam being weighed +as a check on the feed-water measurements. A number of thermometers and +thermo-couples were used to obtain atmospheric-air temperature, +temperatures of the air entering and leaving the boilers, and feed-water +temperature. + +The apparatus is now being reconstructed with appliances for measuring +the quantity of air entering the furnace, and an automatic +electric-furnace temperature regulator. + + [Illustration: PLATE XIX. + + Fig. 1.--Gas Producer, Economizer, and Wet Scrubber. + + Fig. 2.--Producer Gas: Dry Scrubber and Gas Holder.] + +Three sizes of boiler have been tested thus far, the dimensions being as +given in Table 4. + +Each of the three boilers was tested at several temperatures of entering +air, up to 1,500° Fahr., about ten tests being made at each temperature. +It is also the intention to run, on these three boilers, about eight +tests at temperatures of 1,800°, 2,100° and 2,400° Fahr., respectively. +A bulletin on the work already done, together with much incidental +matter, is in course of preparation.[18] + + TABLE 4.--Dimensions of Boilers Nos. 1, 2, and 3. + + ------------------------------------+--------+--------+-------- + Items. | Boiler | Boiler | Boiler + | No. 1. | No. 2. | No. 3. + ------------------------------------+--------+--------+-------- + Distance, outside to outside of | | | + boiler heads, in inches | 8.28 | 8.28 | 16.125 + Actual outside diameter of flues, | 0.252 | 0.313 | 0.252 + in inches | | | + Actual inside diameter of flues, | 0.175 | 0.230 | 0.175 + in inches | | | + Number of flues (tubes) | 10 | 10 | 10 + ------------------------------------+--------+--------+-------- + +The work on the first three boilers is only a beginning; preparations +are being made to test eight more multi-tubular boilers of various +lengths and tube diameters, under similar conditions. Because of the +experience already obtained, it will be necessary to make only eight +tests at each initial air temperature. + +When the work on multi-tubular boilers is completed, water-tube boilers +will be taken up, for which a fairly complete outline has been prepared. +This second or water-tube portion of the investigation is really of the +greater scientific and commercial interest, but the multi-tubular +boilers were investigated first because the mathematical treatment is +much simpler. + +_Producer-Gas Tests._--The producer-gas plant at the Pittsburg testing +station is in charge of Mr. Carl D. Smith, and has been installed for +the purpose of testing low-grade fuel, bone coal, roof coal, mine +refuse, and such material as is usually considered of little value, or +even worthless for power purposes. The gas engine, gas producer, +economizer, wet scrubber (Fig. 1, Plate XIX), and accessories, are in +Building No. 13, and the dry scrubber, gas-holder, and water-cooling +apparatus are immediately outside that building (Fig. 2, Plate XIX). + +At present immense quantities of fuel are left at the mines, in the form +of culm and slack, which, in quality, are much below the average output. +Such fuel is considered of little or no value, chiefly because there is +no apparatus in general use which can burn it to good advantage. The +heat value of this fuel is often from 50 to 75% of that of the fuel +marketed, and if not utilized, represents an immense waste of natural +resources. Large quantities of low-grade fuel are also left in the +mines, simply because present conditions do not warrant its extraction, +and it is left in such a way that it will be very difficult, if not +practically impossible, for future generations to take out such fuel +when it will be at a premium. Again, there are large deposits of +low-grade coal in regions far remote from the sources of the present +fuel supply, but where its successful and economic utilization would be +a boon to the community and a material advantage to the country at +large. The great importance of the successful utilization of low-grade +fuel is obvious. Until within very recent years little had been +accomplished along these lines, and there was little hope of ever being +able to use these fuels successfully. + +The development of the gas producer for the utilization of ordinary +fuels,[19] however, indicates that the successful utilization of +practically all low-grade fuel is well within the range of possibility. +It is notable that, although all producer-gas tests at the Government +testing stations, at St. Louis and Norfolk, were made in a type of +producer[20] designed primarily for a good grade of anthracite coal, the +fuels tested included a wide range of bituminous coals and lignites, and +even peat and bone coal, and that, in nearly every test, little serious +difficulty was encountered in maintaining satisfactory operating +conditions.[21] It is interesting to note that in one test, a bone coal +containing more than 45% of ash was easily handled in the producer, and +that practically full load was maintained for the regulation test period +of 50 hours.[22] + +It is not expected that all the fuels tested will prove to be of +immediate commercial value, but it is hoped that much light will be +thrown on this important problem. + + [Illustration: PLATE XX. + + Fig. 1.--Charging Floor of Gas Producer. + + Fig. 2.--European and American Briquettes.] + +The equipment for this work consists of a single gas generator, rated at +150 h.p., and a three-cylinder, vertical gas engine of the same +capacity. The producer is a Loomis-Pettibone, down-draft, made by the +Power and Mining Machinery Company, of Cudahy, Wis., and is known as its +“Type C” plant. The gas generator consists of a cylindrical shell, 6 ft. +in diameter, carefully lined with fire-brick, and having an internal +diameter of approximately 4 ft. Near the bottom of the generator there +is a fire-brick grate, on which the fuel bed rests. The fuel is charged +at the top of the producer through a door (Fig. 1, Plate XX), which may +be left open a considerable time without affecting the operation of the +producer, thus enabling the operator to watch and control the fuel bed +with little inconvenience. As the gas is generated, it passes downward +through the hot fuel bed and through the fire-brick grate. This +down-draft feature “fixes,” or makes into permanent gases, the tarry +vapors which are distilled from bituminous coal when it is first charged +into the producer. A motor-driven exhauster with a capacity of 375 cu. +ft. per min., draws the hot gas from the base of the producer through an +economizer, where the sensible heat of the gas is used to pre-heat the +air and to form the water vapor necessary for the operation of the +producer. The pre-heated air and vapor leave the economizer and enter +the producer through a passageway near the top and above the fuel bed. +From the economizer the gas is drawn through a wet scrubber where it +undergoes a further cooling and is cleansed of dirt and dust. After +passing the wet scrubber, the gas, under a light pressure, is forced, by +the exhauster, through a dry scrubber to a gas-holder with a capacity of +about 1,000 cu. ft. + +All the fuel used is carefully weighed on scales which are checked from +time to time by standard weights; and, as the fuel is charged into the +producer, a sample is taken for chemical analysis and for the +determination of its calorific power. The water required for the +generation of the vapor is supplied from a small tank carefully +graduated to pounds; this observation is made and recorded every hour. +All the water used in the wet scrubber is measured by passing it through +a piston-type water meter, which is calibrated from time to time to +insure a fair degree of accuracy in the measurement. Provision is made +for observing the pressure and temperature of the gas at various points; +these are observed and recorded every hour. + +From the holder the gas passes through a large meter to the vertical +three-cylinder Westinghouse engine, which is connected by a belt to a +175-kw., direct-current generator. The load on the generator is measured +by carefully calibrated switch-board instruments, and is regulated by a +specially constructed water rheostat which stands in front of the +building. + +Careful notes are kept of the engine operation; the gas consumption and +the load on the engine are observed and recorded every 20 min.; the +quantity of jacket water used on the gas engine, and also its +temperature entering and leaving the engine jackets, are recorded every +hour. Indicator cards are taken every 2 hours. The work is continuous, +and each day is divided into three shifts of 8 hours each; the length of +a test, however, is determined very largely by the character and +behavior of the fuel used. + +A preliminary study of the relative efficiency of the coals found in +different portions of the United States, as producers of illuminating +gas, has been nearly completed under the direction of Mr. Alfred H. +White, and a bulletin setting forth the results is in press.[23] + +_Tests of Liquid Fuels._--Tests of liquid fuels in internal-combustion +engines, in charge of Mr. R. M. Strong, are conducted in the engine-room +of Building No. 13. + +The various liquid hydro-carbon fuels used in internal-combustion +engines for producing power, range from the light refined oils, such as +naphtha, to the crude petroleums, and have a correspondingly wide +variation of physical and chemical properties. + +The most satisfactory of the liquid fuels for use in internal-combustion +engines, are alcohol and the light refined hydro-carbon oils, such as +gasoline. These fuels, however, are the most expensive in commercial +use, even when consumed with the highest practical efficiency, which, it +is thought, has already been attained, as far as present types of +engines are concerned. + +At present little is known as to how far many of the very cheap +distillates and crude petroleums can be used as fuel for +internal-combustion engines. It is difficult to use them at all, +regardless of efficiency. + +Gasoline is comparatively constant in quality, and can be used with +equal efficiency in any gasoline engine of the better grade. There are +many makes of high-grade gasoline engines, tests on any of which may be +taken as representative of the performance and action of gasoline in an +internal-combustion engine, if the conditions under which the tests were +made are clearly stated and are similar. + +Kerosene varies widely in quality, and requires special devices for its +use, but is a little cheaper than gasoline. It is possible that the +kerosene engine may be developed so as to permit it to take the place of +the smaller stationary and marine gasoline engines. This would mean +considerable saving in fuel cost to the small power user, who now finds +the liquid-fuel internal-combustion engine of commercial advantage. A +number of engines at present on the market use kerosene; some use only +the lighter grades and are at best comparatively less efficient than +gasoline engines. All these engines have to be adjusted to the grade of +oil to be used in order to get the best results. + +Kerosene engines are of two general types: the external-vaporizer type, +in which the fuel is vaporized and mixed with air before or as it is +taken into the cylinder; and the internal-vaporizer type, in which the +liquid fuel is forced into the cylinder and vaporized by contact with +the hot gases or heated walls of a combustion chamber at the head of the +cylinder. A number of special devices for vaporizing kerosene and the +lighter distillates have been tried and used with some success. Heat is +necessary to vaporize the kerosene as quickly as it is required, and the +degree of heat must be held between the temperature of vaporization and +that at which the oil will be carbonized. The vapor must also be +thoroughly and uniformly mixed with air in order to obtain complete +combustion. As yet, no reliable data on these limiting temperatures for +kerosene and similar oils have been obtained. No investigation has ever +been made of possible methods for preventing the oils from carbonizing +at the higher temperatures, and the properties of explosive mixtures of +oil vapors and air have not been studied. This field of engineering +laboratory research is of vital importance to the solution of the +kerosene-engine problem. + +Distillates or fuel oils and the crude oils are much the cheapest of the +liquid fuels, and if used efficiently in internal-combustion engines +would be by far the cheapest fuels available in many large districts. + +Several engine builders are developing kerosene vaporizers, which are +built as a part of the engine, or are adapted to each different engine, +as required to obtain the best results. Most of these vaporizers use the +heat and the exhaust gases to vaporize the fuel, but they differ greatly +in construction; some are of the retort type, and others are of the +float-feed carburetter type. To what extent the lower-grade fuel oils +can be used with these vaporizers is yet to be determined. + +There are only a few successful oil engines on the American market. The +most prominent of these represent specific applications of the principal +methods of internal vaporization, and all except one are of the hot-bulb +ignition type. It will probably be found that no one of the 4-stroke +cycle, or 2-stroke cycle, engines is best for all grades of oil, but +rather that each is best for some one grade. The Diesel engine is in a +class by itself, its cycle and method of control being somewhat +different from the others. + +An investigation of the comparative adaptability of gasoline and alcohol +to use in internal-combustion engines, consisting of more than 2,000 +tests, was made at the temporary fuel-testing plant of the Geological +Survey, at Norfolk, Va., in 1907. A detailed report of these tests is in +preparation.[24] A similar investigation of the comparative adaptability +of kerosenes has been commenced, with a view to obtaining data on their +economical use, leading up to the investigation of the comparative fuel +values of the cheaper distillates and crude petroleum, as before +discussed. + +_Washing and Coking Tests._--The investigations relating to the +preparation of low-grade coals, such as those high in ash or sulphur, by +processes that will give them a higher market value or increase their +efficiency in use, are in charge of Mr. A. W. Belden. They include the +washing and coking tests of coals, and the briquetting of slack and +low-grade coal and culm-bank refuse so as to adapt these fuels for +combustion in furnaces, etc. + +This work has been conducted in the washery and coking plant temporarily +located at Denver, Colo., and in Building No. 32 at the Pittsburg +testing station, where briquetting is in progress. The details of these +tests are set forth in the various bulletins issued by the Geological +Survey.[25] + +The washing tests are carried out in the following manner: As the raw +coal is received at the plant, it is shoveled from the railroad cars to +the hopper scale, and weighed. It then passes through the tooth-roll +crusher, where the lumps are broken down to a maximum size of 2½ in. An +apron conveyor delivers the coal to an elevator which raises it to one +of the storage bins. As the coal is being elevated, an average sample +representing the whole shipment is taken. An analysis is made of this +sample of raw coal and float-and-sink tests are run to determine the +size to which it is necessary to crush before washing, and the +percentage of refuse with the best separation. From the data thus +obtained, the washing machines are adjusted so that the washing test is +made with full knowledge of the separations possible under varying +percentages of refuse. The raw coal is drawn from the bin and delivered +to a corrugated-roll disintegrator, where it is crushed to the size +found most suitable, and is then delivered by the raw-coal elevator to +another storage bin. The arrangement of the plant is such that the coal +may be first washed on a Stewart jig, and the refuse then delivered to +and re-washed on a special jig, or the refuse may be re-crushed and then +re-washed. + +When the coal is to be washed, it drops to the sluice box, where it is +mixed with the water and sluiced to the jigs. In drawing off the washed +coal, or when the uncrushed raw coal is to be drawn from a bin and +crushed for the washing tests, however, a gate just below the coal-flow +regulating gate is thrown in, and the coal falls into a central hopper +instead of into the sluice box. Ordinarily, this gate forms one side of +the vertical chute. The coal in this central hopper is carried by a +chute to the apron conveyor, and thence to the roll disintegrator, or, +in case it is washed coal, to a swing-hammer crusher. It will be noted +that coal, in this manner, can be drawn from a bin at the same time that +coal is being taken from another bin, and sluiced to the jigs for +washing, the two operations not interfering in the least. + +The washed coal, after being crushed and elevated to the top of the +building, is conveyed by a chute to the coke-oven larry, and is weighed +on the track scale, after which it is charged to the oven. The refuse is +sampled and weighed as it is wheeled to the dump pile, and from this +sample the analysis is made and a float-and-sink test run to determine +the “loss of good coal” in the refuse and to show the efficiency of the +washing test. + +The coking tests have been conducted in a battery of two beehive ovens, +one 7 ft. high and 12 ft. in diameter, the other, 6¼ ft. high and +12 ft. in diameter. A standard larry with a capacity of 8 tons, and +the necessary scales for weighing accurately the coal charged and coke +produced, complete the equipment. The coal is usually run through a roll +crusher which breaks it to about ½-in. size, or through a Pennsylvania +hammer crusher. The fineness of the coals put through the hammer crusher +varies somewhat, but the average, taken from a large number of samples, +is as follows: Through ⅛-in. mesh, 100%; over 10-mesh, 31.43%; over +20-mesh, 24.29%; over 40-mesh, 22.86%; over 60-mesh, 10 per cent. The +results of the coking tests are set forth in detail in the various +publications issued on this subject.[26] + +Tests of coke produced in the illuminating-gas investigations before +referred to, and a study of commercial coking and by-product plants, are +included in these investigations. + +_Briquetting Investigations._--These investigations are in charge of Mr. +C. L. Wright, and are conducted in Building No. 32, which is of +fire-proof construction, having a steel-skeleton frame work, +reinforced-concrete floors, and 2-in. cement curtain walls, plastered on +expanded-metal laths. In this building two briquetting machines are +installed, one an English machine of the Johnson type, and the other a +German lignite machine of very powerful construction. + +The investigations include the possibility of making satisfactory +commercial fuels from lignite or low-grade coals which do not stand +shipment well, the benefiting of culm or slack coals which are wasted or +sold at unremunerative prices, and the possibility of improving the +efficiency of good coals. Some of the various forms of commercial +briquettes, American and foreign, are shown in Fig. 2, Plate XX. After +undergoing chemical analysis, the coal is elevated and fed to a storage +bin, whence it is drawn through a chute to a hopper on the weighing +scales. There it is mixed with varying percentages of different kinds of +binding material, and the tests are conducted so as to ascertain the +most suitable binder for each kind of fuel, which will produce the most +durable and weather-proof briquette at least cost, and the minimum +quantity necessary to produce a good, firm briquette. After weighing, +the materials to be tested are run through the necessary grinding and +pulverizing machines and are fed into the briquetting machines, whence +the manufactured briquettes are delivered for loading or storage. The +materials to be used in the German machine are also dried and cooled +again. + + [Illustration: PLATE XXI. + + Fig. 1.--Hand Briquetting Press. + + Fig. 2.--Coal Briquetting Machine.] + +The briquettes made at this plant are then subjected to physical tests +in order to determine their weathering qualities and their resistance to +abrasion; extraction tests and chemical analyses are also made. +Meanwhile other briquettes from the same lots are subjected to +combustion tests for comparison with the same coal not briquetted. These +tests are made in stationary boilers, in house-heating boilers, on +locomotives, naval vessels, etc., and the results, both of the processes +of manufacture, and of the tests, are published in various bulletins +issued by the Geological Survey.[27] + +The equipment includes storage bins for the raw coal, scales for +weighing, machines for crushing or cracking the pitch, grinders, +crushers, and disintegrators for reducing the coal to the desired +fineness, heating and mixing apparatus, presses and moulds for forming +the briquettes, a Schulz drier, and a cooling apparatus. + +There is a small experimental hand-briquetting press (Fig. 1, Plate XXI) +for making preliminary tests of the briquetting qualities of the various +coals and lignites. With this it is easily possible to vary the +pressure, heat, percentage and kind of binder, so as to determine the +best briquetting conditions for each fuel before subjecting it to +large-scale commercial tests in the big briquetting machines. + +This hand press will exert pressures up to 50 tons or 100,000 lb. per +sq. in., on a plunger 3 in. in diameter. This plunger enters a mould, +which can be heated by a steam jacket supplied with ordinary saturated +steam at a pressure of 125 lb., and compresses the fuel into a +briquette, 8 in. long, under the conditions of temperature and pressure +desired. + +The Johnson briquetting machine, which requires 25 h.p. for its +operation, exerts a pressure of about 2,500 lb. per sq. in., and makes +briquettes of rectangular form, 6¾ by 4¼ by 2½ in., and having an +average weight of about 3¾ lb. The capacity of the machine (Fig. 2, +Plate XXI) is about 3.8 tons of briquettes per 8-hour day. + +Under the hopper on the scales for the raw material is a square wooden +reciprocal plunger which pushes the fuel into a hole in the floor at a +uniform rate. The pitch is added as uniformly as possible by hand, as +the coal passes this hole. Under this hole a horizontal screw conveyor +carries the fuel and pitch to the disintegrator, in front of which, in +the feeding chute, there is a powerful magnet for picking out any pieces +of iron which might enter the machine and cause trouble. + +The ground mixture is elevated from the disintegrator to a point above +the top of the upper mixer of the machine. At the base of this cylinder, +steam can be admitted by several openings to heat the material to any +desired temperature, usually from 180° to 205° Fahr. There, a plunger, +making 17 strokes per min., compresses two briquettes at each stroke. + +The German lignite-briquetting machine (Figs. 18 and 19) was made by the +Maschinenfabrik Buckau Actien-Gesellschaft, Magdeburg, Germany. Lignite +from the storage room on the third floor of the building is fed into one +end of a Schulz tubular drier (Fig. 1, Plate XXII), which is similar to +a multi-tubular boiler set at a slight angle from the horizontal, and +slowly revolved by worm and wheel gearing, the lignite passing through +the tubes and the steam being within the boiler. From this drier the +lignite passes through a sorting sieve and crushing rolls to a cooling +apparatus, which consists of four horizontal circular plates, about 13 +ft. in diameter, over which the dried material is moved by rakes. After +cooling, the material is carried by a long, worm conveyor to a large +hopper over the briquette press, and by a feeding box to the press (Fig. +2, Plate XXII). + +The press, which is of the open-mould type, consists of a ram and die +plates, the latter being set so as to make a tube which gradually tapers +toward the delivery end of the machine. The briquettes have a +cross-section similar to an ellipse with the ends slightly cut off; they +are about 1¼ in. thick and average about 1 lb. in weight (Fig. 2, Plate +XX). The press is operated by a direct connection with a steam engine of +150 h.p., the base of which is continuous with that of the press. The +exhaust steam from the engine is used to heat the driver. + +The plunger makes from 80 to 100 strokes per min., the pressure exerted +ranging from 14,000 to 28,000 lb. per sq. in., the capacity of the +machine being 1 briquette per stroke, or from 2½ to 3 tons of completed +briquettes per hour. It is expected that no binder will be needed for +practically all the brown lignite briquetted by this machine, thus +reducing the cost as compared with the briquetting of coals, which +require from 5 to 7% of water-gas, pitch binder costing more than 50 +cents per ton of manufactured briquettes. + + [Illustration: Fig. 18. + + LONGITUDINAL-SECTION OF LIGNITE-BRIQUETTING PLANT] + + + [Illustration: Fig. 19. + + CROSS-SECTION OF LIGNITE-BRIQUETTING PLANT] + +_Peat Investigations._--Investigations into the distribution, +production, origin, nature, and uses of peat are being conducted by Mr. +C. A. Davis, and include co-operative arrangements with State Geological +Surveys and the Geologic Branch of the U.S. Geological Survey. These +organizations conduct surveys which include the mapping of the peat +deposits in the field, the determination of their extent and +limitations, the sampling of peat from various depths, and the +transmittal of samples to the Pittsburg laboratories for analysis and +test.[28] + +This work is co-ordinated in such a manner as to result in uniform +methods of procedure in studying the peat deposits of the United States. +The samples of peat are subjected to microscopic examination, in order +to determine their origin and age, and to chemical and physical tests at +the laboratories in Pittsburg, so as to ascertain the chemical +composition and calorific value, the resistance to compressive strains, +the ash and moisture content, drying properties, resistance to abrasion, +etc. Occasionally, large quantities of peat are disintegrated and +machined, and portions, after drying for different periods, are +subjected to combustion tests in steam boilers and to tests in the gas +producer, to ascertain their efficiency as power producers. + +_Results._--The full value of such investigations as have been described +in the preceding pages cannot be realized for many years; but, even +within the four years during which this work has been under way, certain +investigations have led to important results, some of which may be +briefly mentioned: + +The chemical and calorific determinations of coals purchased for the use +of the Government have resulted in the delivery of a better grade of +fuel without corresponding increase in cost, and, consequently, in +saving to the Government. Under this system, of purchasing its coal +under specifications and testing, the Government is getting more nearly +what it pays for and is paying for what it gets. These investigations, +by suggesting changes in equipment and methods, are also indicating the +practicability of the purchase of cheaper fuels, such as bituminous coal +and the smaller sizes of pea, buckwheat, etc., instead of the more +expensive sizes of anthracite, with a corresponding saving in cost. The +Government’s fuel bill now aggregates about $10,000,000 yearly. + + [Illustration: PLATE XXII. + + Fig. 1.--Dryer for Lignite Briquetting Press. + + Fig. 2.--Lignite Briquetting Machine.] + +The making and assembling of chemical analyses and calorific +determinations (checked by other tests) of carefully selected samples of +coals from nearly 1,000 different localities, in the different coal +fields of the United States, with the additions, from time to time, of +samples representing parts of coal fields or newly opened beds of coal +in the same field, furnish invaluable sources of accurate information, +not only for use of the Government, but also for the general public. Of +the above-mentioned localities, 501 were in the public-land States and +427 in the Central, Eastern, and Southern States. + +The chemical analyses of the coals found throughout the United States +have been made with such uniformity of method, both as to collection +of samples and analytical procedure, as to yield results strictly +comparable for coals from all parts of the country, and furnish complete +information, as a basis for future purchases and use by the Government +and by the general public, of all types of American coals. + +Other researches have resulted in the acquirement of valuable +information regarding the distribution of temperature in the fuel bed of +gas producers and furnaces, showing a range of from 400° to 1,300° +cent., and have thus furnished data indicating specific difficulties to +be overcome in gas-producer improvements for greater fuel efficiency. + +The recent studies of the volatile matter in coal, and its relation to +the operation of coke ovens and other forms of combustion, have +demonstrated that as much as one-third of this matter is inert and +non-combustible, a fact which may have a direct bearing on smoke +prevention by explaining its cause and indicating means for its +abatement. + +Experiments in the storage of coal have proven that oxygen is absorbed +during exposure to air, thereby causing, in some cases, a deterioration +in heating value, and indicating that, for certain coals, in case they +are to be stored a long time for naval and other purposes, storage under +water is advisable. + +The tests of different coals under steam boilers have shown the +possibility of increasing the general efficiency of hand-fired steam +boilers from 10 to 15% over ordinary results. If this saving could be +made in the great number of hand-fired boilers now being operated in all +parts of the United States, it would result in large saving in the fuel +bill of the country. Experiments which have been made with +residence-heating boilers justify the belief that it will be possible to +perfect such types of boilers as may economically give a smokeless +operation. The tests under steam boilers furnish specific information as +to the most efficient method of utilizing each of a number of different +types of coal in Government buildings and power plants in different +parts of the country. + +The tests in the gas producer have shown that many fuels of such low +grade as to be practically valueless for steam-furnace purposes, +including slack coal, bone coal, and lignite, may be economically +converted into producer gas, and may thus generate sufficient power to +render them of high commercial value. + +Practically every shipment out of several hundred tested in the gas +producers, including coals as high in ash content as 45%, and lignites +and peats high in moisture, has been successfully converted into +producer gas which has been used in operating gas engines. It has been +estimated that on an average there was developed from each coal tested +in the gas-producer plant two and one-half times the power developed +when used in the ordinary steam-boiler plant, and that such relative +efficiencies will probably hold good for the average plant of moderate +power capacity, though this ratio may be greatly reduced in large steam +plants of the most modern type. It was found that the low-grade lignites +of North Dakota developed as much power, when converted into producer +gas, as did the best West Virginia bituminous coals when utilized under +the steam boiler; and, in this way, lignite beds underlying from +20,000,000 to 30,000,000 acres of public lands, supposed to have little +or no commercial value, are shown to have a large value for power +development. + +The tests made with reference to the manufacture and combustion of +briquetted coal have demonstrated conclusively that by this means many +low-grade bituminous coals and lignites may have their commercial value +increased to an extent which more than covers the increased cost of +making; and these tests have also shown that bituminous coals of the +higher grades may be burned in locomotives with greatly increased +efficiency and capacity and with less smoke than the same coal not +briquetted. These tests have shown that, with the same fuel consumption +of briquettes as of raw coal, the same locomotive can very materially +increase its hauling capacity and thus reduce the cost of +transportation. + +The investigations into smoke abatement have indicated clearly that each +type of coal may be burned practically without smoke in some type of +furnace or with some arrangement of mechanical stoker, draft, etc. The +elimination of smoke means more complete combustion of the fuel, and +consequently less waste and higher efficiency. + +The investigations into the waste of coal in mining have shown the +enormous extent of this waste, aggregating probably from 300,000,000 to +400,000,000 tons yearly, of which at least one-half might be saved. It +is being demonstrated that the low-grade coals, high in sulphur and ash, +now left underground, can be used economically in the gas producer for +power and light, and, therefore, should be mined at the same time that +the high-grade coal is being removed. Moreover, attention is now being +called to the practicability of a further large reduction of waste +through more efficient mining methods. + +The washing tests have demonstrated the fact that many coals, too high +in ash and sulphur for economic use under the steam boiler or for +coking, may be rendered of commercial value by proper treatment in the +washery. The coking tests have also demonstrated that, by proper methods +of preparation for and manipulation in the beehive oven, many coals +which were not supposed to be of economic value for coking purposes, may +be rendered so by prior washing and proper treatment. Of more than 100 +coals tested during 1906 from the Mississippi Valley and the Eastern +States, most of which coals were regarded as non-coking, all except 6 +were found, by careful manipulation, to make fairly good coke for +foundry and other metallurgical purposes. Of 52 coals from the Rocky +Mountain region, all but 3 produced good coke under proper treatment, +though a number of these had been considered non-coking coals. + +Investigations into the relative efficiency of gasoline and denatured +alcohol as power producers, undertaken in connection with work for the +Navy Department, have demonstrated that with proper manipulation of the +carburetters, igniters, degree of compression, etc., denatured alcohol +has the same power-producing value, gallon for gallon, as gasoline. This +is a most interesting development, in view of the fact that the heat +value of a gallon of alcohol is only a little more than 0.6 that of a +gallon of gasoline. To secure these results, compressions of from 150 to +180 lb. per sq. in. were used, these pressures involving an increase in +weight of engine. Although the engine especially designed for alcohol +will be heavier than a gasoline engine of the same size, it will have a +sufficiently greater power capacity so that the weight per horse-power +need not be greater. + +Several hundred tons of peat have been tested to determine methods of +drying, compressing into briquettes, and utilization for power +production in the gas producer. In connection with these peat +investigations, a reconnoissance survey has been made of the peat +deposits of the Atlantic Coast. Samples have been obtained by boring to +different depths in many widely distributed peat-bogs, and these samples +have been analyzed and tested in order to determine their origin, +nature, and fuel value. + +The extent and number of tests from which these results have been +derived will be appreciated from the fact that, in three years, nearly +15,000 tests were made, in each of which large quantities of fuel were +consumed. These tests involved nearly 1,250,000 physical observations +and 67,080 chemical determinations, made with a view to analyze the +results of the tests and to indicate any necessary changes in the +methods as they progressed. For coking, cupola, and washing, 596 tests, +of which nearly 300 involved the use of nearly 1,000 tons of coal, have +been made at Denver. For briquetting, 312 tests have been made. +Briquettes have been used in combustion tests in which 250 tons of +briquetted coal were consumed in battleship tests, 210 tons in +torpedo-boat tests, 320 tons in locomotive tests on three railway +systems, and 70 tons were consumed under stationary steam boilers. Of +producer gas tests, 175 have been made, of which 7 were long-time runs +of a week or more in duration, consuming in all 105 tons of coal. There +have been 300 house-heating boiler tests and 575 steam-boiler tests; +also, 83 railway-locomotive and 23 naval-vessel tests have been made on +run-of-mine coal in comparison with briquetted coal; also, 125 tests +have been made in connection with heat-transmission experiments, and +2,254 gasoline- and alcohol-engine tests. Nearly 10,000 samples of coal +were taken for analysis, of which 3,000 were from public-land States. +Nearly 5,000 inspection samples, of coal purchased by the Government for +its use, have been taken and tested. + +The results of the tests made in the course of these investigations, as +summarized, have been published in twelve separate Bulletins, three of +which, Nos. 261, 290, and 332, set forth in detail the operations of the +fuel-testing plant for 1904, 1905, and 1906. Professional Paper No. 48, +in three volumes, describes in greater detail each stage of the +operations for 1904 and 1905. + +Separate Bulletins, descriptive of the methods and results of the work +in detail, have been published, as follows: No. 323, Experimental work +conducted in the chemical laboratory; No. 325, A study of four hundred +steaming tests; No. 334, Burning of coal without smoke in boiler plants; +No. 336, Washing and coking tests of coal, and cupola tests of coke; No. +339, Purchase of coal under specifications on basis of heating value; +No. 343, Binders for coal briquettes; No. 362, Mine sampling and +chemical analyses of coals in 1907; No. 363, Comparative tests of +run-of-mine and briquetted coal on locomotives, including torpedo-boat +tests, and some foreign specifications for briquetted fuel; No. 366, +Tests of coal and briquettes as fuel for house-heating boilers; No. 367, +Significance of drafts in steam-boiler practice; No. 368, Coking and +washing tests of coal at Denver; No. 373, Smokeless combustion of coal +in boiler plants, with a chapter on central heating plants; No. 378, +Results of purchasing coal under Government specifications; No. 382, +The effect of oxygen in coal; and, No. 385, Briquetting tests at +Norfolk, Va. + + + + +DISCUSSION + + +KENNETH ALLEN, M. Am. Soc. C. E.--The speaker would like to know whether +anything has been done in the United States toward utilizing marsh mud +for fuel. + +In an address by Mr. Edward Atkinson, before the New England Water Works +Association, in 1904, on the subject of “Bog Fuel,” he referred to its +extensive use in Sweden and elsewhere, and intimated that there was a +wide field for its use in America. + +The percentage of combustible material in the mud of ordinary marsh +lands is very considerable, and there are enormous deposits readily +available; but it is hardly probable that its calorific value is +sufficiently high to render its general use at this time profitable. + +As an example of the amount of organic matter which may remain stored in +these muds for many years, the speaker would mention a sample taken from +the bottom of a trench, which he had analyzed a few years ago. Although +taken from a depth of about 15 ft., much of the vegetable fiber remained +intact. The material proved to be 70¾% volatile. + +Possibly before the existing available coal deposits are exhausted, the +exploitation of meadow muds for fuel may become profitable. + + +HENRY KREISINGER, Esq.[29] (by letter).--Mr. Wilson gives a brief +description of a long furnace and an outline of the research work which +is being done in it. It may be well to discuss somewhat more fully the +proposed investigations and point out the practical value of the +findings to which they may lead. + +In general, the object is to study the process of combustion of coal. +When soft coal is burned in any furnace, part of the combustible is +driven off shortly after charging, and has to be burned in the space +between the fuel bed and the exit of the gases, which is called the +combustion space. There is enough evidence to show that, with a constant +air supply, the completeness of the combustion of the volatile +combustible depends on the length of time the latter stays within the +combustion space; but, with a constant rate of charging the coal, this +length of time depends directly on the extent of the combustion space. +Thus, if the volume of the volatile combustible evolved per second and +the admixed air is 40 cu. ft., and the extent of the combustion space is +80 cu. ft., the average time the gas will stay within the latter is 2 +sec.; if the combustion space is 20 cu. ft., the average time the +mixture can stay in this space is only ½ sec., and its combustion will +be less complete than in the first case. Thus it is seen that the extent +of the combustion space of a furnace is an important factor in the +economic combustion of volatile coals. The specific object of the +investigations, thus far planned, is to determine the extent of the +combustion space required to attain practically complete combustion when +a given quantity of a given coal is burned under definite conditions. +With this object in view, the furnace has been provided with a +combustion space large enough for the highest volatile coals and for the +highest customary rate of combustion. To illustrate the application of +the data which will be obtained by these experiments, the following +queries are given: + +Suppose it is required to design a furnace which will burn coal from a +certain Illinois mine at the rate of 1,000 lb. per hour, with a +resulting temperature of not less than 2,800° Fahr. How large a +combustion space is required to burn, with practical completeness, the +volatile combustible? What completeness of combustion can be attained, +if the combustion space is only three-fourths of the required extent? In +the present state of the knowledge of the process of combustion of coal, +these queries cannot be answered definitely. In the literature on +combustion one may find statements that the gases must be completely +burned before leaving the furnace or before they strike the cooling +surfaces of the boiler; but there is no definite information available +as to how long the gases must be kept in the furnace or how large the +combustion space must be in order to obtain practically complete +combustion. It is strange that so little is known of such an old art as +the combustion of coal. + +The research work under consideration is fundamentally a problem in +physical chemistry, and, for that reason, has been assigned to a +committee consisting of the writer as Engineer, Dr. J. C. W. Frazer, +Chemist, and Dr. J. K. Clement, Physicist. The outcome of the +investigation may prove of extreme interest to mechanical and fuel +engineers, and to all who have anything to do with the burning of coal +or the construction of furnaces. In the experiments thus far planned the +following factors will be considered: + +_Effect of the Nature of Coal on the Extent of Combustion Space +Required._--The steaming coals mined in different localities evolve +different volumes of volatile combustible, even when burned at the same +rate. The coal which analyzes 45% of volatile matter evolves a much +greater volume of gases and tar vapors than that analyzing only 15 per +cent. These evolved gases and tar vapors must be burned in the space. +Consequently, a furnace burning high volatile coal must have a much +larger combustion space than that burning coal low in volatile +combustible. + +There is enough evidence to show that the extent of combustion space +required to burn the volatile combustible depends, not only on the +volume of the combustible mixture, but also on the chemical composition +of the volatile combustible. Thus the volatile combustible of low +volatile coal, when mixed with an equal volume of air, may require 1 +sec. in the combustion space to burn practically to completeness, while +it may require 2 sec. to burn the same volume of the volatile +combustible of high volatile coal with the same completeness; so that +the extent of the combustion space required to burn various kinds of +coal may not be directly proportional to the volatile matter of the +coal. + +_Effect of the Rate of Combustion on the Extent of Combustion Space +Required._--With the same coal, the volume of the volatile combustible +distilled from the fuel bed per unit of time varies as the rate of +combustion. Thus, when this rate is double that of the standard, the +volume of gases and tar vapors driven from the fuel is about doubled. To +this increased volume of volatile combustible, about double the volume +of air must be added, and, if the mixture is to be kept the same length +of time within the combustion space, the latter should be about twice as +large as for the standard rate of combustion. Thus the combustion space +required for complete combustion varies, not only with the nature of the +coal, but also with the rate of firing the fuel, which, of course, is +self-evident. + +_Effect of Air Supply on the Extent of Combustion Space +Required._--Another factor which influences the extent of the combustion +space is the quantity of air mixed with the volatile combustible. +Perhaps, within certain limits, the combustion space may be decreased +when the supply of air is increased. However, any statement at present +is only speculation; the facts must be determined experimentally. One +fact is known, namely, that, in order to obtain higher temperatures of +the products of combustion, the air supply must be decreased. + +_Effect of Rate of Heating of Coal on the Extent of Combustion Space +Required._--There is still another factor, a very important one, which, +with a given coal and any given air supply, will influence the extent of +the combustion space. This factor is the rate of heating of the coal +when feeding it into the furnace. The so-called “proximate” analysis of +coal is indeed only very approximate. When the analysis shows, say, 40% +of volatile matter and 45% of fixed carbon, it does not mean that the +coal is actually composed of so much volatile matter and so much fixed +carbon; it simply means that, under a certain rate of heating attained +by certain standard laboratory conditions, 40% of the coal has been +driven off as “volatile matter.” If the rate or method of heating were +different, the amount of volatile matter driven off would also be +different. Chemists state that it is difficult to obtain accurate checks +on “proximate” analysis. To illustrate this factor, further reference +may be made to the operation of the up-draft bituminous gas producers. +In the generator of such producers the tar vapors leave the freshly +fired fuel, pass through the wet scrubber, and are finally separated by +the tar extractor as a black, pasty substance in a semi-liquid state. If +this tar is subjected to the standard proximate analysis, it will be +shown that from 40 to 50% of it is fixed carbon, although it left the +gas generator as volatile matter. It is desired to emphasize the fact +that different rates of heating of high volatile coals will not only +drive off different percentages of volatile matter, but that the latter +itself varies greatly in chemical composition and physical properties as +regards inflammability and rapidity of combustion. Thus it may be said +that the extent of the combustion space required for the complete +oxidation of the volatile combustible depends on the method of charging +the fuel, that is, on how rapidly the fresh fuel is heated. If this +factor is given proper consideration, it may be possible to reduce very +materially the necessary space required for complete combustion. + +_The Effect of the Rate of Mixing the Volatile Combustible and Air on +the Extent of the Combustion Space._--When studying the effects +discussed in the preceding paragraphs, the rate of mixing the volatile +combustible with the supply of air must be as constant as practicable. +At first, tests will be made with no special mixing devices, the mixing +will be accomplished entirely by the streams of air entering the furnace +at the stoker, and by natural diffusion. Although there appears to be +violent stirring of the gases above the fuel bed, the mixture of the +gases does not become homogeneous until they are about 10 or 15 ft. from +the stoker. The mixing caused by the air currents forced into the +furnace at the stoker is very distinct, and can be readily observed +through the peep-hole in the side wall of the Heine boiler, opposite the +long combustion chamber. This mixing is shown in Fig. 20. _A_ is a +current of air forced from the ash-pit directly upward through the fuel +bed; _B_ and _B_ are streams of air forced above the fuel bed through +numerous small openings at the furnace side of each hopper. Those +currents cause the gases to flow out of the furnace in two spirals, as +shown in Fig. 20. The velocity of rotation on the outside of the two +spirals appears to be about 10 ft. per sec., when the rate of combustion +is about 750 lb. of coal per hour. It is reasonable to expect that when +the rate of mixing is increased by building piers and other mixing +structures immediately back of the grate, the completeness of the +combustion will be effected in less time, and a smaller combustion space +will be required. Thus, the mixing structures may be an important factor +in the extent of the required combustion space. + +To sum up, it can be said that the extent of the space required to +obtain a combustion which can be considered complete for all practical +purposes, depends on the following factors: + + (_a_).--Nature of coal, + + (_b_).--Rate of combustion, + + (_c_).--Supply of air, + + (_d_).--Rate of heating fuel, + + (_e_).--Rate of mixing volatile combustible and air. + +Just how much the extent of the combustion space required will be +influenced by these factors is the object of the experiments under +discussion. + +_The Scope of the Experiments._--With this object in view, as explained +in the preceding paragraphs, the following series of experiments are +planned: + + [Illustration: Fig. 20. + + SECTION THROUGH STOKER SHOWING MIXING OF GASES + CAUSED BY CURRENTS OF AIR] + +Six or eight typical coals are to be selected, each representing a +certain group of nearly the same chemical composition. Each series will +consist of several sets of tests, each set being run with all the +conditions constant except the one, the effect of which on the size of +the combustion space is to be investigated. Thus a set of four or five +tests will be made, varying in rate of combustion from 20 to 80 lb. of +coal per square foot of grate per hour, keeping the supply of air per +pound of combustible and the rate of heating constant. This set will +show the effect of the rate of combustion of the coal on the extent of +space required to obtain combustion which is practically complete. Other +variables, such as composition of coal, supply of air, and rate of +heating, remain constant. + +Another set of four or five tests will be made with the same coal and at +the same rate of combustion, but the air supply will be different for +each test. This set of tests will be repeated for two or three different +rates of combustion. Thus each of these sets will give the effect of the +air supply on the extent of combustion space when the coal and rate of +combustion remain constant. + +Still another set of tests should be made in which the time of heating +the coal when feeding it into the furnace will vary from 3 to 30 min. In +each of the tests of this set, the rate of combustion and the air supply +will be kept constant, and the set will be repeated for two or three +rates of combustion and two or three supplies of air. Each of these sets +of tests will give the effect of the rate of heating of fresh fuel on +the extent of combustion space required to burn the distilled volatile +combustible. These sets of experiments will require a modification in +the stoker mechanism, and, on that account, may be put off until all the +other tests on the other selected typical coals are completed. As the +investigation proceeds, enough may be learned so that the number of +tests in each series may be gradually reduced. After all the desirable +tests are made with the furnace as it stands, several kinds of mixing +structures will be built successively back of the stoker and tried, one +kind at a time, with a set of representative tests. Thus the +effectiveness of such mixing structures will be determined. + +_Determining the Completeness of Combustion._--The completeness of +combustion in the successive cross-sections of the stream of gases is +determined mainly by the chemical analysis of samples of gases collected +through the openings at these respective cross-sections. The first of +these cross-sections at which gas samples are collected, passes through +the middle of the bridge wall; the others are placed at intervals of 5 +ft. through the entire length of the furnace. Measurements of the +temperature of the gases, and direct observations of the length and +color of the flames and of any visible smoke will be also made through +the side peep-holes. These direct observations, together with the gas +analysis, will furnish enough data to determine the length of travel of +the combustible mixture to reach practically complete combustion. + +In other words, these observations will determine the extent of the +combustion space for various kinds of coal when burned under certain +given conditions. Direct observations and the analysis of gases at +sections nearer the stoker than that at which the combustion is +practically complete, will show how the process of combustion approaches +its completion. This information will be of extreme value in determining +the effect of shortening the combustion space on the loss of heat due to +incomplete combustion. + +_Method of Collecting Gas Samples._--The collection of gas samples is a +difficult problem in itself, when one considers that the temperature of +the gases, as they are in the furnace, ranges from 2,400° to 3,200° +Fahr.; consequently, the samples must be collected with water-cooled +tubes. Thus far, about 25 preliminary tests have been made. These tests +show that the composition of the gases at the cross-sections near the +stoker is not uniform, and that more than one sample must be taken from +each cross-section. It was decided to take 9 samples from the +cross-section immediately back of the stoker, and reduce the number in +the sections following, according to the uniformity of the gas +composition. Thus, about 35 simultaneous gas samples must be taken for +each test. The samples will be subjected, not only to the usual +determination of CO_{2}, O_{2} and CO, but to a complete analysis. It is +also realized that some of the carbon-hydrogen compounds which, at the +furnace temperature, exist as heavy gases, are condensed to liquids and +solids when cooled in the sampling tubes, where they settle and tend to +clog it. To neglect the presence of this form of the combustible would +introduce considerable error in the determination of the completeness of +combustion at any of the cross-sections. Therefore, special water-cooled +sampling tubes are constructed and equipped with filters which separate +the liquid and solid combustible from the gases. The contents of these +filters are then also subjected to complete analysis. To obtain +quantitative data, a measured quantity of gases must be drawn through +these filtering sampling tubes. + +_The Measuring of Temperatures._--At present the only possible known +method of measuring the temperature of the furnace gases is by optical +and radiation pyrometers. Platinum thermo-couples are soon destroyed by +the corrosive action of the hot gases. The pyrometers used at present +are the Wanner optical pyrometer and the Fery radiation pyrometer. + +_The Flow of Heat Through Furnace Walls._--An interesting side +investigation has developed, in the study of the loss of heat through +the furnace walls. In the description of this experimental furnace it +has been said that the side walls contained a 2-in. air space, which, in +the roof, was replaced with a 1-in. layer of asbestos. To determine the +relative resistance to heat flow of the air space and the asbestos +layer, 20 thermo-couples were embedded, in groups of four, to different +depths at three places in the side wall and at two places in the roof. +In the side wall, one of the thermo-couples of each group was placed in +the inner wall near the furnace surface; the second thermo-couple was +placed in the same wall, but near the surface facing the air space; the +third thermo-couple was placed in the outer wall near the inner surface; +and the fourth was placed near the outer surface in the outer wall. In +the roof the second and third thermo-couples were placed in the brick +near the surface on each side of the asbestos layer. These +thermo-couples have shown that the temperature drop across the 2-in. air +space was much less than that across the 1-in. layer of asbestos; in +fact, that it was considerably less than the temperature drop through +the same thickness of the brick wall. + +The results obtained prove that, as far as heat insulation is concerned, +air spaces in furnace walls are undesirable. The heat is not conducted +through the air, but leaps across the space by radiation. In furnace +construction a solid wall is a better heat insulator than one of the +same total thickness containing an air space. If it is necessary to +build a furnace wall in two parts on account of unequal expansion, the +space between the two walls should be filled with some solid, cheap, +non-conducting materials, such as ash, sand, or crushed brick. A more +detailed account of these experiments may be found in a Bulletin of the +U.S. Geological Survey entitled “The Flow of Heat Through Furnace +Walls.” + + +WALTER O. SNELLING, Esq.[30] (by letter).--The work of the United States +Testing Station at Pittsburg has been set forth so fully by Mr. Wilson +that a further statement as to the results achieved may seem like +repetition. It would be most unlikely, however, that studies of such +variety should possess no other value than along the direct lines being +investigated. In the case of the Mine Accidents Division, at least, it +is certain that the indirect benefits of some of the studies have been +far-reaching, and are now proving of value in lines far removed from +those which were the primary object of the investigation. They are +developing facts which will be of great value to all engineers or +contractors engaged in tunneling or quarrying. As the writer’s +experience has been solely in connection with the chemical examination +of explosives, he will confine his discussion to this phase. + +In studying the properties of various explosives, and in testing work to +separate those in which the danger of igniting explosive mixtures of +coal dust and air, or of fire-damp and air, is greatest, from those in +which this danger is least, much information has been collected. Mr. +Wilson has described many of the tests, and it can be readily seen that +in carrying out these and other tests on each of the explosives +submitted, a great many facts relating to the properties of explosive +compounds have been obtained, which were soon found to be of decided +value in directions other than the simple differentiation of explosives +which are safe from those which are unsafe in the presence of explosive +mixtures of fire-damp or coal dust. + +The factors which determine the suitability of an explosive for work in +material of any particular physical characteristics depend on the +relationship of such properties as percussive force (or the initial blow +produced by the products of the decomposition of the explosive at the +moment of explosion), and the heaving force (or the continued pressure +produced by the products of the decomposition, after the initial blow at +the instant of detonation). Where an explosive has been used in coal or +rock of a certain degree of brittleness, and where the work of the +explosive with that particular coal is not thoroughly satisfactory, it +becomes evident that through the systematic use of the information +available at the Testing Station (and now in course of publication in +the form of bulletins), in regard to the relationship between percussive +and heaving forces in different explosives, as shown by the tests with +small lead blocks, the Trauzl test, and the ballistic pendulum, that +explosives can be selected which, possessing in modified form the +properties of the explosive not entirely satisfactory in that type of +coal or rock, would combine all the favorable properties of the first +explosive, together with such additional advantages as would come from +its added adaptation to the material in which it is to be used. + +For example, if the explosive in use were found to have too great a +shattering effect on the coal, an examination of the small lead-block +test of this explosive, and a comparison of this with lead-block tests +of other explosives having practically the same strength, as shown by +the ballistic pendulum, will enable the mine manager to select from +those already on the Permissible List (and therefore vouched for in +regard to safety in the presence of gas and coal dust, when used in a +proper way), some explosive which will have the same strength, and yet +which, because of lessened percussive force or shattering effect, will +produce coal in the manner desired. If one takes the other extreme, and +considers a mine in which the product is used exclusively for the +preparation of coke (and therefore where shattering of the coal is in no +way a disadvantage), the mine superintendent’s interest will be +primarily to select an explosive which, as indicated by suitable +lead-block, Trauzl, and ballistic pendulum tests, will produce the +greatest amount of coal at the least cost. + +As the cost of the explosive does not form any part of the tables +prepared by the Testing Station, the relative cost must be computed from +the manufacturer’s prices, but the results tabulated by the Station will +contain all the other data necessary to give the mine superintendent +(who cares to take the small amount of trouble necessary to familiarize +himself with the tables) all the information which is required to +compare the action of one explosive with that of any other explosive +tested. + +In this way it is seen that, aside from the primary consideration of +safety in the presence of explosive mixtures of fire-damp and coal dust +(a condition alike fulfilled by all explosives admitted to the +Permissible List), the data prepared by the Testing Station also give +the information necessary to enable the discriminating mine manager to +select an explosive adapted to the particular physical qualities of the +coal at his mine, or to decide intelligently between two explosives of +the same cost on the basis of their actual energy content in the +particular form of the heaving or percussive force required in his work. + +Up to the present time the investigations have been confined to +explosives used in coal mining, because the Act of Congress establishing +the Testing Station has thus limited its work. Accordingly, it is not +possible to compare, on the systematic basis just mentioned, the +explosives generally used in rock work. It is probable that, if the Bill +now before Congress in regard to the establishment of a Bureau of Mines +is passed, work of this character will be undertaken, and the tables of +explosives now prepared will be extended to cover all those intended for +general mining and quarrying use. Data of such character are +unobtainable to-day, and, as a result, a considerable percentage of +explosives now used in all mining operations is wasted, because of their +lack of adaptation to the materials being blasted. It is well known, for +example, that when an explosive of high percussive force is used in +excavating in a soft or easily compressed medium, a considerable +percentage of its force is wasted as heat energy, performing no other +function than the distortion and compression of the material in which it +is fired, without exerting either an appreciable cracking or fissuring +effect, or a heaving or throwing of the material. + +Owing to lack of information in regard to the exact relationship between +the percussive and the heaving force in particular explosives, this +waste, as compared with the quantity required for the work with a +properly balanced material, will continue; but it is to be hoped that it +will soon be possible to give the mining and quarrying industries +suitable information in regard to the properties of the various +explosives, so that the railroad contractor and the metal miner may have +the same simple and exact means of discrimination between suitable and +unsuitable explosives that is now being provided for the benefit of the +coal miner. + +Another of the important but indirect benefits of this work has been the +production of uniformity of strength and composition in explosives. An +example of this helpful influence is the standardization of detonating +caps and electric detonators. In the early days of the explosive +industry, it was apparently advantageous for each manufacturer to have a +separate system of trade nomenclature by which to designate the +strengths of the different detonators manufactured by him. The necessity +and even the advantage of such methods have long been outgrown, and yet, +until the past year, the explosive industry has had to labor under +conditions which made it almost impossible for the user of explosives to +compare, in cost or strength, detonators of different manufacturers; or +to select intelligently the detonator best suited to the explosive to be +used. After conference with the manufacturers of detonating caps and +electric detonators, a standard system of naming the strengths of these +products has been selected by the Testing Station, and has met with a +most hearty response. It is encouraging to note that, in recent trade +catalogues, detonators are named in such a way as to enable the user to +determine directly the strength of the contained charge, which is a +decided advantage to every user of explosives and also to manufacturers. + +The uniformity of composition of explosives (and many difficulties in +mining work and many accidents have been rightly or wrongly attributed +to lack of uniformity) may be considered as settled in regard to all +those on the Permissible List. One of the conditions required of every +explosive on that list is that its composition must continue +substantially the same as the samples submitted originally for official +test. Up to the present, all explosives admitted to the Permissible List +have maintained their original composition, as determined by subsequent +analyses of samples selected from mines in which the explosive was in +use, and comparison with the original samples. + +The data assembled by the Testing Station in regard to particular +explosives have also been of great benefit to the manufacturers. When +the explosives tests were commenced, comparatively few explosives were +being made in the United States for which it was even claimed by the +manufacturers that they were at all safe in the presence of explosive +mixtures of gas or coal dust. It was evident that, without systematic +tests, very little knowledge of the safety or lack of safety of any +particular explosive could ever be gained, and, consequently, the user +of explosives was apt to regard with incredulity any claim by the +manufacturer in regard to the qualities of safety. Owing to lack of +proof, this was most natural; and it was also evident that the very slow +process of testing, which was offered by a study of mine explosions +during past years, was sufficient only to prove the danger of black +powder, and not in any way to indicate the safety of any of the brands +of mining powder for which this property was claimed. Indeed, one of the +few explosives to which the name, “safety,” was attached, at the time +the Government experiments were first undertaken, was found to be +anything but safe when tested in the gallery, although there is no +reason to believe that the makers of this and other explosives claiming +“safety” for their product, did not have the fullest confidence in their +safety. + +The Testing Station offered the first opportunity in the United States +to obtain facts in regard to the danger of any particular explosive in +the presence of explosive mixtures of gas or coal dust. With most +commendable energy, the manufacturers of explosives, noting the early +failures of their powders in the testing gallery, began at once to +modify them in such ways as suggested by the behavior of the explosives +when under test, and, in a short time, returned to the Testing Station +with improved products, able to stand the severe tests required. In this +way the Testing Station has been a most active agent in increasing the +general safety of explosives, and the manufacturers have shown clearly +that it never was their desire to offer inferior explosives to the +public, but that their failures in the past were due solely to lack of +information in regard to the action of explosives under the conditions +which exist before a mine disaster. The chance being offered to +duplicate, at the Testing Station, the conditions represented in a mine +in the presence of gas, they showed an eagerness to modify and improve +their explosives so as to enable them to answer severe mining +conditions, which is most commendable to American industry. + +In regard to the unfavorable conditions existing in mines in the past, +the same arguments may be used. In spite of the frequency of mine +accidents in the United States, and in spite of the high death rate in +coal mining as compared with that in other countries, it must be said in +fairness that this has been the result of ignorance of the actual +conditions which produce mine explosions, rather than any willful +disregard of the known laws of safety by mine owners. Conditions in +American mines are far different from those obtaining in mines abroad, +and, as a result, the rules which years of experience had taught to +foreign colliery managers were not quickly applied to conditions +existing in American mines; but, as soon as the work at the Pittsburg +Station had demonstrated the explosibility of the coal dust from +adjoining mines, and had shown the very great safety of some explosives +as compared with others, there was at once a readiness on the part of +mine owners throughout the country to improve conditions in their mines, +and to take advantage of all the studies made by the Government, thus +showing clearly that the disasters of the past had been due to lack of +sufficient information rather that to any willful disregard of the value +of human lives. + +Another of the indirect benefits of the work of the Station has resulted +from its examination of explosives for the Panama Canal. For several +years the Isthmian Canal Commission has been one of the largest users of +explosives in the world, and, in the purchase of the enormous quantities +required, it was found necessary to establish a system of careful +examination and inspection. This was done in order to insure the safety +of the explosives delivered on the Isthmus, and also to make certain +that the standards named in the contract were being maintained at all +times. With its established corps of chemists and engineers, it was +natural that this important work should be taken up by the Technologic +Branch of the United States Geological Survey, and, during the past +three years, many millions of pounds of dynamite have been inspected and +samples analyzed by the chemists connected with the Pittsburg Testing +Station, thus insuring the high standard of these materials. + +One of the many ways in which this work for the Canal Commission has +proved of advantage is shown by the fact that, as a result of studies at +the Testing Station, electric detonators are being made to-day which, in +water-proof qualities, are greatly superior to any similar product. As +the improvements of these detonators were made by a member of the +testing staff, all the pecuniary advantages arising from them have gone +directly to the Government, which to-day is obtaining superior electric +detonators, and at a cost of about one-third of the price of the former +materials. + +All the work of the Technologic Branch is being carried out along +eminently practical lines, and is far removed from such work as can be +taken up advantageously by private or by State agencies. The work of the +Mine Accidents Division was taken up primarily to reduce the number of +mine accidents, and to increase the general conditions of safety in +mining. As the work of this Division has progressed, it has been found +to be of great advantage to the miner and the mine owner, while the +ultimate results of the studies will be of still greater value to every +consumer of coal, as they will insure a continued supply of this +valuable product, and at a lower cost than if the present methods, +wasteful alike in lives and in coal, had been allowed to continue for +another decade. + + +A. BARTOCCINI, Assoc. M. Am. Soc. C. E. (by letter).--The writer made a +personal investigation of the mine disaster of Cherry, Ill. He +interviewed the men who escaped on the day of the accident, and also +several of those who were rescued one week later. He also interrogated +the superintendent and the engineer of the mine, and obtained all the +information asked for and also the plans of the mine showing the +progress of the work. + +After a careful investigation the writer found that the following +conditions existed at the mine at the time of the disaster: + + _First._--There were no means for extinguishing fires in the mine. + + _Second._--There were no signal systems of any kind. Had the mine been + provided with electric signals and telephones, like some of the most + modern mines in the United States, the majority of the men could have + been saved, by getting into communication with the outside and working + in conjunction with the rescuers. + + _Third._--The miners had never received instructions of how to behave + in case of fire. + + _Fourth._--The main entries and stables were lighted with open + torches. + + _Fifth._--The organization of the mine was defective in some way, for + at the time of the disaster orders came from every direction. + + _Sixth._--The air shaft was used also as a hoisting shaft. + + _Seventh._--The main shaft practically reached only to the second + vein; its extension to the third and deepest vein was not used. + + _Eighth._--Plans of the workings of the second and third veins were + not up to date. The last survey recorded on them was that of June, + 1909. This would have made rescue work almost impossible to men not + familiar with the mine. + + _Ninth._--The inside survey of the mine was not connected with the + outside survey. + +Would it not be possible for the United States Geological Survey to +enforce rules which would prevent the existence of conditions such as +those mentioned? The Survey is doing wonderful work, as shown by the +rescue of twenty miners at Cherry one week after the conflagration; but +there is no doubt that perhaps all the men could have been saved if +telephone communications with the outside had been established. +Telephone lines to resist any kind of a fire, can easily be installed, +and the expense is small, almost negligible when one considers the +enormous losses suffered by the mine owners and by the families of the +victims. + + +H. G. STOTT, M. Am. Soc. C. E.--The curves shown by Mr. Wilson give a +clear general idea of the relative efficiencies of steam and gas engines +when treated from a purely theoretical thermodynamic point of view. This +point of view, however, is only justified when small units having a +maximum brake horse-power not exceeding 1,000 are considered. + +The steam engine or turbine operating under a gauge pressure of 200 lb. +per sq. in., and with 150° superheat, has a maximum temperature of 538° +Fahr. in its cylinder, while that of the gas engine varies between +2,000° and 3,000° Fahr. + +The lubrication of a surface continually subjected to the latter +temperature would be impossible, so that water jackets on the cylinders +and, in the larger units, in the pistons become absolutely necessary. As +the cylinders increase in diameter, it is necessary, of course, to +increase their strength in proportion to their area, which, in turn, is +proportional to the square of the diameter. The cooling surface, +however, is only proportional to the circumference, or a single function +of the diameter. Increasing the strength in proportion to the square of +the diameter soon leads to difficulties, because of the fact that the +flow of heat through a metal is a comparatively slow process; the thick +walls of the cylinders on large engines cannot conduct the heat away +fast enough, and all sorts of strains are set up in the metal, due to +the enormous difference in temperature between the inside and the jacket +lining of the cylinder. + +These conditions produce cut and cracked cylinders, with a natural +resultant of high maintenance and depreciation costs. These costs, in +some cases, have been so great, not only in the United States, but in +Europe and Africa, as to cause the complete abandonment of large gas +engine plants after a few years of attempted operation. + +The first consideration in any power plant is that it shall be +thoroughly reliable in operation, and the second is that it shall be +economical, not only in operation, but in maintenance and depreciation. +Therefore, in using the comparative efficiency curves shown in Mr. +Wilson’s paper it should be kept in mind that the cost of power is not +only the fuel cost, but the fuel plus the maintenance and depreciation +charges, and that the latter items should not be taken from the first +year’s account, but as an average of at least five years. + +The small gas engine is a very satisfactory apparatus when supplied with +good, clean gas, and when given proper attention, but great caution +should be used before investing in large units, until further +developments in the art take place, as conservation of capital is just +as important as conservation of coal. + + +B. W. DUNN, Esq.[31] (by letter.)--The growing importance of +investigations of explosives, with a view to increasing the consumer’s +knowledge of proper methods for handling and using them, is evident when +it is noted that the total production of explosives in the United States +has grown from less than 9,000,000 lb. in 1840 to about 215,000,000 lb. +in 1905. Table 5 has been compiled by the Bureau of Explosives of the +American Railway Association. + + TABLE 5.--Manufacture of Explosives in the United States, 1909. + + ---------------------+-------------+------------------------------ + Kind of explosives. | Number of | Maximum Capacity, in Pounds. + | factories. +--------------+--------------- + | | Daily. | Annual. + ---------------------+-------------+--------------+--------------- + Black powder | 49 | 1,220,150 | 366,135,000 + High explosives | 37 | 1,203,935 | 361,180,500 + Smokeless powders | 5 | 75,686 | 22,705,800 + ---------------------+-------------+--------------+--------------- + +The first problem presented by this phenomenal increase relates to the +safe transportation of this material from the factories to points of +consumption. A package of explosives may make many journeys through +densely populated centers, and rest temporarily in many widely separated +storehouses before it reaches its final destination. A comprehensive +view of the entire railway mileage of the United States would show at +any instant about 5,000 cars partially or completely loaded with +explosives. More than 1,200 storage magazines are listed by the Bureau +of Explosives as sources of shipments of explosives by rail. + +The increase in the demand for explosives has not been due entirely to +the increase in mining operations. The civil engineer has been expanding +his use of them until now carloads of dynamite, used on the Isthmus of +Panama in a single blast, bring to the steam shovels as much as 75,000 +cu. yd. of material, the dislodgment of which by manual labor would have +required days of time and hundreds of men. Without the assistance of +explosives, the construction of subways and the driving of tunnels would +be impracticable. Even the farmer has awakened to the value of this +concentrated source of power, and he uses it for the cheap and effective +uprooting of large stumps over extended areas in Oregon, while an entire +acre of subsoil in South Carolina, too refractory for the plow, is +broken up and made available for successful cultivation by one explosion +of a series of well-placed charges of dynamite. It has also been found +by experience that a few cents’ worth of explosive will be as effective +as a dollar’s worth of manual labor in preparing holes for transplanting +trees. + +The use of explosives in war and in preparation for war is now almost a +negligible quantity when compared with the general demand from peaceful +industries. With the completion of the Panama Canal, it is estimated +that the Government will have used in that work alone more explosives +than have been expended in all the battles of history. + +Until a few years ago little interest was manifested by the public in +safeguarding the manufacture, transportation, storage, and use of +explosives. Anyone possessing the necessary degree of ignorance, or +rashness, was free to engage in their manufacture with incomplete +equipment; they were transported by many railroads without any special +precautions; the location of magazines in the immediate vicinity of +dwellings, railways, and public highways, was criticized only after some +disastrous explosion; and the often inexperienced consumer was without +access to a competent and disinterested source of information such as he +now has in the testing plant at Pittsburg so well described by Mr. +Wilson. + +The first general move to improve these conditions is believed to have +been made by the American Railway Association in April, 1905. It +resulted in the organization of a Bureau of Explosives which, through +its inspectors, now exercises supervision over the transportation of all +kinds of dangerous articles on 223,630 of the 245,000 miles of railways +in the United States and Canada. A general idea of the kind and volume +of inspection work is shown by the following extracts from the Annual +Report of the Chief Inspector, dated February, 1910: + + 1909. 1908. + “Total number of railway lines members of + Bureau December 31st 172 158 + Total mileage of Bureau lines December 31st 209,984 202,186 + Total number of inspections of stations for + explosives 6,953 5,603 + Number of stations receiving two or more + inspections for explosives 1,839 1,309 + Total number of inspections of stations + for inflammables 6,950 1,098 + Number of stations receiving two or more + inspections for inflammables 1,886 .... + Total number of inspections of factories 278 270 + Number of factories receiving two or more + inspections 75 69 + Total number of inspections of magazines 1,293 1,540 + Number of magazines receiving two or more + inspections 349 361 + Total number of boxes of high explosives + condemned as unsafe for transportation 10,029 4,852 + Total number of kegs of black powder + condemned as unsafe for transportation 1,468 531 + Total number of cars in transit containing + explosives inspected 475 448 + Total number of cars in transit showing serious + violations of the regulations 168 197 + Total number of inspections of steamship + companies’ piers + (inflammable, 75; explosive, 63) 138 .... + Total number of inspections made by Bureau 16,087 8,959 + Total number of lectures to railway officials + and employes and meetings addressed on the + subject of safe transportation of explosives + and other dangerous articles 215 171 + + 1909. 1908. 1907. + “Total number of accidents resulting + in explosions or fires in + transportation of explosives by rail 12 22 79 + Total known property loss account + explosions or accidents in + transporting explosives by rail $2,673 $114,629 $496,820 + Total number of persons injured by + explosions in transit 7 53 80 + Total number of persons killed by + explosions in transit 6 26 52 + + “During the same period reports have been rendered to the Chief + Inspector by the Chemical Laboratory of the Bureau on 734 samples, + as follows: + + Explosives 211 + Fireworks 186 + Inflammables 304 + Paper for lining high explosive boxes 31 + Ammunition 2 + ---- + Total 734 + + “As a means of ensuring the uniform enforcement of the regulations, by + a well grounded appreciation of their significance and application, + the lectures delivered by representatives of the Bureau have proved + most successful. The promulgation of the regulations is not of itself + sufficient to ensure uniformity or efficiency in their observance, and + so these lectures form a valuable supplement to the inspection + service. They have been successfully continued throughout the year, + and the requests for the delivery of them by the managements of so + many of the membership lines, is a convincing testimonial of the high + esteem in which they are held. + + “While the lectures are primarily intended for the instruction and + information of the officials and employes of the railway companies, + and especially of those whose duties bring them into immediate contact + with the dangerous articles handled in transportation, the + manufacturers and shippers are invited, and they have attended them in + considerable numbers. Many of this class have voluntarily expressed + their commendation of the lectures as a medium of education, and + signified their approval of them in flattering terms. + + “The scope of these lectures embraces elementary instruction in the + characteristics of explosives and inflammables and the hazards + encountered in their transportation and in what respects the + regulations afford protection against them. The requirements of the + law, and the attendant penalties for violation, are fully described. + Methods of preparation, packing, marking, receiving, handling and + delivering, are explained by stereopticon lantern slides. These are + interesting of themselves, and are the best means of stamping the + impression they are intended to convey upon the minds of the + audiences, and are always an acceptable feature of the lectures. The + reception generally given to the lectures by those who have attended + them, often at the voluntary surrender of time intended for rest while + off duty, may be stated as an indication that the subject matter is + one in which they are interested. + + “The facilities of the Young Men’s Christian Association, in halls, + lanterns and skilled lantern operators, have been generously accorded + and made use of to great advantage, in connection with the lectures at + many places. The co-operation of this Association affords a convenient + and economical method of securing the above facilities, and the + Association has expressed its satisfaction with the arrangement as in + line with the educational features which they provide for their + members. + + “During the year 1909, 215 lectures were delivered at various points + throughout the United States.” + +The Bureau of Explosives, of the American Railway Association, and the +Bureau of Mines, of the United States Geological Survey, were +independent products of a general agitation due to the appreciation by a +limited number of public-spirited citizens of the gravity of the +“explosive” problem. It is the plain duty of the average citizen to +become familiar with work of this kind prosecuted in his behalf. He may +be able to help the work by assisting to overcome misguided opposition +to it. Evidences of this opposition may be noted in the efforts of some +shippers to avoid the expense of providing suitable shipping containers +for explosives and inflammable articles, and in the threats of miners’ +labor unions to strike rather than use permissible explosives instead of +black powder in mining coal in gaseous or dusty mines. + +Too much credit cannot be given Messrs. Holmes and Wilson, and other +officials of the Technologic Branch of the United States Geological +Survey, for the investigations described in this paper. They are +establishing reasonable standards for many structural materials; they +are teaching the manufacturer what he can and should produce, and the +consumer what he has a right to demand; with scientific accuracy they +are pointing the way to a conservation of our natural resources and to a +saving of life which will repay the nation many times for the cost of +their work. + +When these facts become thoroughly appreciated and digested by the +average citizen, these gentlemen and their able assistants will have no +further cause to fear the withdrawal of financial or moral support for +their work. + + +HERBERT M. WILSON, M. Am. Soc. C. E. (by letter).--The Fuel Division of +the United States Geological Survey has given considerable attention to +the use of peat as a fuel for combustion under boiler furnaces, in gas +producers, and for other purposes. It is doubtless to this material that +Mr. Allen refers in speaking of utilizing “marsh mud for fuel,” since he +refers to an address by Mr. Edward Atkinson on the subject of “Bog Fuel” +in which he characterized peat by the more popular term “marsh mud.” + +In Europe, where fuel is expensive, 10,000,000 tons of peat are used +annually for fuel purposes. A preliminary and incomplete examination, +made by Mr. C. A. Davis, of the Fuel Division of the Geological Survey, +indicates that the peat beds of the United States extend throughout an +area of more than 11,000 sq. miles. The larger part of this is in New +England, New York, Minnesota, Wisconsin, New Jersey, Virginia, and other +Coastal States which contain little or no coal. It has been estimated +that this area will produce 13,000,000,000 tons of air-dried peat. + +At present peat production is in its infancy in the United States, +though there are in operation several commercial plants which find a +ready market for their product and are being operated at a profit. A +test was made at the Pittsburg plant on North Carolina peat operated in +a gas producer--the resulting producer gas being used to run a gas +engine of 150 h.p.--the load on which was measured on a switch-board. +Peat containing nearly 30% of ash and 15% of water gave 1 commercial +horse-power-hour for each 4 lb. of peat fired in the producer. Had the +peat cost $2 per ton to dig and prepare for the producer, each +horse-power-hour developed would have cost 0.4 of a cent. The fuel cost +of running an electric plant properly equipped for using peat fuel, of +even this low grade, in the gas producer would be about $4 per 100 h.p. +developed per 10-hour day. + +Equally good results were procured in tests of Florida and Michigan peat +operated in the gas producer. The investigations of peat under Mr. Davis +include studies of simple commercial methods of drying, the chemical and +fuel value, analyses of the peat, studies of the mechanical methods of +digging and disintegrating the peat, and physical tests to determine the +strength of air-dried peat to support a load. + +The calorific value of peat, as shown by numerous analyses made by the +United States Geological Survey, runs from about 7,500 to nearly 11,000 +B.t.u., moisture free, including the ash, which varies from less than 2% +to 20%, the latter being considered in Europe the limit of commercial +use for fuel. Analyses of 25 samples of peat from Florida, within these +limits as to ash, show a range of from 8,269 to 10,865 B.t.u., only four +of the series being below 9,000 B.t.u., and four exceeding 10,500 +B.t.u., moisture free. Such fuel in Florida is likely to be utilized +soon, since it only needs to be dug and dried in order to render it fit +for the furnace or gas producer. Many bituminous coals now used +commercially have fuel value as low as 11,000 B.t.u., moisture free, and +with maximum ash content of 20%; buckwheat anthracite averages near the +same figures, often running as high as 24% ash. + +One bulletin concerning the peats of Maine has been published, and +another, concerning the peat industries of the United States, is in +course of publication. + +Mr. Bartoccini asks whether it would not be possible for the United +States Geological Survey to enforce rules which would prevent the +existence of conditions such as occurred at the mine disaster of Cherry, +Ill. + +The United States Government has no police power within the States, and +it is not within its province to enact or enforce rules or laws, or even +to make police inspection regarding the methods of operating mining +properties. The province of the mine accidents investigations and that +of its successor, the Bureau of Mines, is, within the States, like that +of other and similar Government bureaus in the Interior Department, the +Department of Agriculture, and other Federal departments, merely to +investigate and disseminate information. It remains for the States to +enact laws and rules applying the remedies which may be indicated as a +result of Federal investigation. + +Investigations are now in progress and tests are being conducted with a +view to issuing circulars concerning the methods of fighting mine fires, +the installation of telephones and other means of signaling, and other +subjects of the kind to which Mr. Bartoccini refers. + +Much as the writer appreciates the kindly and sympathetic spirit of the +discussion of Messrs. Allen and Bartoccini, he appreciates even more +that of Colonel Dunn and Mr. Stott, who are recognized authorities +regarding the subjects they discuss, and of Messrs. Kreisinger and +Snelling, who have added materially to the details presented in the +paper relative to the particular investigations of which they have +charge in Pittsburg. + +Mr. Snelling’s reference to the use of explosives in blasting operations +should be of interest to all civil engineers, as well as to mining +engineers, as should Colonel Dunn’s discussion concerning the means +adopted to safeguard the transportation of explosives. + +Since the presentation of the paper, Congress has enacted a law +establishing, in the Department of the Interior, a United States Bureau +of Mines. To this Bureau have been transferred from the Geological +Survey the fuel-testing and the mine accidents investigations described +in this paper. To the writer it seems a matter for deep regret that the +investigations of the structural materials belonging to and for the use +of the United States, were not also transferred to the same Bureau. On +the last day of the session of Congress, a conference report transferred +these from the Geological Survey to the Bureau of Standards. It is +doubtful whether the continuation of these investigations in that +Bureau, presided over as it is by physicists and chemists of high +scientific attainments, will be of as immediate value to engineers and +to those engaged in building and engineering construction as they would +in the Bureau of Mines, charged as it is with the investigations +pertinent to the mining and quarrying industries, and having in its +employ mining, mechanical, and civil engineers. + + +FOOTNOTES + + [Footnote 1: Presented at the meeting of April 20th, 1910.] + + [Footnote 2: “Coal Mine Accidents,” by Clarence Hall and Walter O. + Snelling. Bulletin No. 333, U.S. Geological Survey, Washington, D.C.] + + [Footnote 3: “The Explosibility of Coal Dust,” by George S. Rice and + others. Bulletin No. * * *, U.S. Geological Survey.] + + [Footnote 4: “Notes on Explosives, Mine Gases and Dusts,” by Rollin + Thomas Chamberlin. Bulletin No. 383, U.S. Geological Survey, 1909.] + + [Footnote 5: “Prevention of Mine Explosions,” by Victor Watteyne, Carl + Meissner, and Arthur Desborough. Bulletin No. 369, U.S. Geological + Survey.] + + [Footnote 6: With a view to obtaining a dust of uniform purity and + inflammability.] + + [Footnote 7: “The Primer of Explosives,” by C. E. Munroe and Clarence + Hall. Bulletin No. 423, U.S. Geological Survey, 1909.] + + [Footnote 8: “Tests of Permissible Explosives,” by Clarence Hall, + W. O. Snelling, S. P. Howell, and J. J. Rutledge. Bulletin No. * * *, + U.S. Geological Survey.] + + [Footnote 9: “Structural Materials Testing Laboratories,” by Richard + L. Humphrey, Bulletin No. 329. U.S. Geological Survey, 1908; + “Portland Cement Mortars and their Constituent Materials,” by Richard + L. Humphrey and William Jordan, Jr., Bulletin No. 331, U.S. Geological + Survey, 1908; “Strength of Concrete Beams,” by Richard L. Humphrey, + Bulletin No. 344, U.S. Geological Survey, 1908.] + + [Footnote 10: “Fire Resistive Properties of Various Building + Materials,” by Richard L. Humphrey, Bulletin No. 370, U.S. Geological + Survey, 1909.] + + [Footnote 11: “Purchasing Coal Under Government Specifications,” by + J. S. Burrows, Bulletin No. 378, U.S. Geological Survey, 1909.] + + [Footnote 12: “Experimental Work in the Chemical Laboratory,” by N. W. + Lord, Bulletin No. 323, U.S. Geological Survey, 1907: “Operations of + the Coal Testing Plant, St. Louis, Mo.” Professional Paper No. 48, + U.S. Geological Survey, 1906.] + + [Footnote 13: Also Bulletins Nos. 290, 332, 334, 363, 366, 367, 373, + 402, 403, and 412, U.S. Geological Survey.] + + [Footnote 14: “Tests of Coal for House Heating Boilers,” by D. T. + Randall, Bulletin No. 336, U.S. Geological Survey, 1908.] + + [Footnote 15: “The Smokeless Combustion of Coal,” by D. T. Randall and + H. W. Weeks, Bulletin No. 373, U.S. Geological Survey, 1909.] + + [Footnote 16: “The Flow of Heat through Furnace Walls,” by W. T. Ray + and H. Kreisinger. Bulletin (in press), U.S. Geological Survey.] + + [Footnote 17: The assumption is made that a metal tube free from scale + will remain almost as cool as the water; actual measurements with + thermo-couples have indicated the correctness of this assumption in + the majority of cases.] + + [Footnote 18: “Heat Transmission into Steam Boilers,” by W. T. Ray and + H. Kreisinger, Bulletin (in press), U.S. Geological Survey.] + + [Footnote 19: “The Producer Gas Power Plant,” by R. H. Fernald, + Bulletin No. 416, U.S. Geological Survey, 1909; also Professional + Paper No. 48 and Bulletins Nos. 290, 316, 332, and 416.] + + [Footnote 20: A Taylor up-draft pressure producer, made by R. D. Wood + and Company, Philadelphia, Pa.] + + [Footnote 21: “Coal Testing Plant, St. Louis, Mo.,” by R. H. Fernald, + Professional Paper No. 48, Vol. III, U.S. Geological Survey, 1906.] + + [Footnote 22: A report of these tests may be found in Bulletin No. + * * *, U.S. Geological Survey.] + + [Footnote 23: “Illuminating Gas Coals,” by A. H. White and Perry + Barker, U.S. Geological Survey.] + + [Footnote 24: “Gasoline and Alcohol Tests,” by R. M. Strong, Bulletin + No. 392, U.S. Geological Survey, 1909.] + + [Footnote 25: “Washing and Coking Tests,” by Richard Moldenke, A. W. + Belden and G. R. Delamater, Bulletin No. 336, U.S. Geological Survey, + 1908; also, “Washing and Coking Tests at Denver, Colo.,” by A. W. + Belden and G. R. Delamater, Bulletin No. 368, U.S. Geological Survey, + 1909.] + + [Footnote 26: U.S. Geological Survey, Professional Paper No. 48, Pt. + III, and Bulletins Nos. 290, 332, 336, 368, 385, and 403.] + + [Footnote 27: Professional Paper No. 48, and Bulletins Nos. 290, 316, + 332, 343, 363, 366, 385, 402, 403, and 412, U.S. Geological Survey.] + + [Footnote 28: “Peat Deposits of Maine,” by E. D. Bastin and C. A. + Davis. Bulletin No. 376, U.S. Geological Survey, 1909.] + + [Footnote 29: U.S. Geological Survey, Pittsburg, Pa.] + + [Footnote 30: Chief Explosives Chemist, U.S. Geological Survey.] + + [Footnote 31: Lieutenant-Colonel, Ordnance Dept., U. S. A.] + + * * * * * + * * * * + * * * * * + +[Errata: + + [Fig. 3. caption] + SAFETY LAMP TESTING GALLERY + _text reads “SAFTY”_ + + [Mine-Rescue Training] + experienced in rescue operations and familiar / with the conditions + existing after mine disasters + _text reads “familar”_ + + so as to determine, if possible, the progress of combustion (Fig. 1, + Plate XVIII). + _text reads “Pate XVIII”_ + + The chemical analyses of the coals + _text reads “anaylses”_ ] + + + + + +End of the Project Gutenberg EBook of Transactions of the American Society +of Civil Engineers, vol. LXX, Dec. 1, by Herbert M. 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LXX, Dec. 1910, by Herbert M. Wilson + +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: Transactions of the American Society of Civil Engineers, vol. LXX, Dec. 1910 + Federal Investigations of Mine Accidents, Structural + Materials and Fuels. Paper No. 1171 + +Author: Herbert M. Wilson + +Release Date: May 25, 2006 [EBook #18448] + +Language: English + +Character set encoding: UTF-8 + +*** START OF THIS PROJECT GUTENBERG EBOOK SOCIETY OF CIVIL ENGINEERS *** + + + + +Produced by Louise Hope, Juliet Sutherland and the Online +Distributed Proofreading Team at http://www.pgdp.net + + + + + + +</pre> + + +<div class = "mynote"> +Page numbers in [brackets] represent full-page illustrations or +unpaginated plates, here placed as close as practicable to their +referring text.<br> +The largest illustrations are shown as thumbnails linked to the +full-size version.<br> +This file includes a few less common fractions such as ⅛ and ⅔. +Passages containing these characters are given in alternate form at the +<a href = "#fractions">end of the text</a>, after the Footnotes. +</div> + +<h3>AMERICAN SOCIETY OF CIVIL ENGINEERS</h3> + +<h6>INSTITUTED 1852</h6> + +<hr class = "tiny"> + +<h2 class = "boldf">TRANSACTIONS</h2> + +<hr class = "tiny"> + +<h4 class = "boldf">Paper No. 1171</h4> + +<hr class = "tiny"> + +<h4>FEDERAL INVESTIGATIONS OF MINE ACCIDENTS,<br> +STRUCTURAL MATERIALS, AND FUELS.<a class = "tag" name = "tag1" href = +"#note1">1</a></h4> + +<h5 class = "smallcaps">By Herbert M. Wilson, M. Am. Soc. C. E.</h5> + +<hr class = "tiny"> + +<h5 class = "smallcaps">With Discussion by Messrs. +Kenneth <a class = "plain" href = "#disc_allen">Allen</a>, +Henry <a class = "plain" href = "#disc_kreisinger">Kreisinger</a>, +Walter O. <a class = "plain" href = "#disc_snelling">Snelling</a>, +A. <a class = "plain" href = "#disc_bartoccini">Bartoccini</a>, +H. G. <a class = "plain" href = "#disc_stott">Stott</a>, +B. W. <a class = "plain" href = "#disc_dunn">Dunn</a>, +and Herbert M. <a class = "plain" href = "#disc_wilson">Wilson</a>.</h5> + +<hr class = "tiny"> + +<h5 class = "smallcaps">Introduction.</h5> + +<p> +The mine disaster, which occurred at Cherry, Ill., on November 13th, +1909, when 527 men were in the mine, resulting in the entombment of 330 +men, of whom 310 were killed, has again focused public attention on the +frequent recurrence of such disasters and their appalling consequences. +Interest in the possible prevention of such disasters, and the possible +means of combating subsequent mine fires and rescuing the imprisoned +miners, has been heightened as it was not even by the series of three +equally extensive disasters which occurred in 1907, for the reason that, +after the Cherry disaster, 20 men were rescued alive after an entombment +of one week, when practically all hope of rescuing any of the miners had +been abandoned.</p> + +<p> +This accident, occurring, as it does, a little more than 1½ years after +the enactment of legislation by Congress instructing the Director of the +United States Geological Survey to investigate the causes and possible +means of preventing the loss of life in coal-mining +<!--png191--> +<span class = "pagenum">191</span> +<a name = "page191"> </a> +operations, makes this an opportune time to review what has been done by +the Geological Survey during this time, toward carrying out the intent +of this Act.</p> + +<p> +It may be stated with confidence, that had such a disaster occurred a +year or more ago, all the entombed men must have perished, as it would +have been impossible to enter the mine without the protection afforded +by artificial respiratory apparatus. Moreover, but for the presence of +the skilled corps of Government engineers, experienced by more than a +year’s training in similar operations in more than twenty disasters, the +mine would have been sealed until the fire had burned out, and neither +the dead, nor those who were found alive, would have been recovered for +many weeks. In the interval great suffering and loss would have been +inflicted on the miners, because of enforced idleness, and on the mine +owners because of continued inability to re-open and resume +operations.</p> + +<p> +<i>Character of the Work.</i>—The United States Geological Survey +has been engaged continuously since 1904 in conducting investigations +relating to structural materials, such as stone, clay, cement, etc., and +in making tests and analyses of the coals, lignites, and other mineral +fuel substances, belonging to, and for the use of, the Government.</p> + +<p> +Incidentally, the Survey has been considering means to increase +efficiency in the use of these resources as fuels and structural +materials, in the hope that the investigations will lead to their best +utilization.</p> + +<p> +These inquiries attracted attention to the waste of human life incident +to the mining of fuel and its preparation for the market, with the +result that, in May, 1908, provision was made by Congress for +investigations into the causes of mine explosions with a view to their +prevention.</p> + +<p> +Statistics collected by the Geological Survey show that the average +death rate in the coal mines of the United States from accidents of all +kinds, including gas and dust explosions, falls of roof, powder +explosions, etc., is three times that of France, Belgium, or Germany. On +the other hand, in no country in the world are natural conditions so +favorable for the safe extraction of coal as in the United States. In +Belgium, foremost in the study of mining conditions, a constant +reduction in the death rate has been secured, and from a rate once +nearly as great as that of the United States, namely, 3.28 per thousand, +in the period 1851-60, it had been reduced to about 2 per thousand in +<!--png192--> +<span class = "pagenum">192</span> +<a name = "page192"> </a> +the period 1881-90; and in the last decade this has been further reduced +to nearly 1 per thousand. It seems certain, from the investigations +already made by the Geological Survey, that better means of safeguarding +the lives of miners will be found, and that the death rate from mine +accidents will soon show a marked reduction.</p> + +<p> +Other statistics collected by the Geological Survey show that, to the +close of 1907, nearly 7,000,000,000 tons of coal had been mined in the +United States, and it is estimated that for every ton mined nearly a ton +has been wasted, 3,500,000,000 tons being left in the ground or thrown +on the dump as of a grade too low for commercial use. To the close of +1907 the production represents an exhaustion of somewhat more than +10,000,000,000 tons of coal. It has been estimated that if the +production continues to increase, from the present annual output of +approximately 415,000,000 tons, at the rate which has prevailed during +the last fifty years, the greater part of the more accessible coal +supply will be exhausted before the middle of the next century.</p> + +<p> +The Forest Service estimates that, at the present rate of consumption, +renewals of growth not being taken into account, the timber supply will +be exhausted within the next quarter of a century. It is desirable, +therefore, that all information possible be gained regarding the most +suitable substitutes for wood for building and engineering construction, +such as iron, stone, clay products, concrete, etc., and that the minimum +proportion in which these materials should be used for a given purpose, +be ascertained. Exhaustion, by use in engineering and building +construction, applies not only to the iron ore, clay, and cement-making +materials, but, in larger ratio, to the fuel essential to rendering +these substances available for materials of construction. Incidentally, +investigations into the waste of structural materials have developed the +fact that the destructive losses, due to fires in combustible buildings, +amount to more than $200,000,000 per annum. A sum even greater than this +is annually expended on fire protection. Inquiries looking to the +reduction of fire losses are being conducted in order to ascertain the +most suitable fire-resisting materials for building construction.</p> + +<p> +Early in 1904, during the Louisiana Purchase Exposition, Congress made +provision for tests, demonstrations, and investigations concerning the +fuels and structural materials of the United States. These +investigations were organized subsequently as the Technologic Branch +<!--png193--> +<span class = "pagenum">193</span> +<a name = "page193"> </a> +of the United States Geological Survey, under Mr. Joseph A. Holmes, +Expert in Charge, and the President of the United States invited a group +of civilian engineers and Chiefs of Engineering Bureaus of the +Government to act as a National Advisory Board concerning the method of +conducting this work, with a view to making it of more immediate benefit +to the Government and to the people of the United States. This Society +is formally represented on this Board by C. C. Schneider, +Past-President, Am. Soc. C. E., and George S. Webster, M. Am. Soc. +C. E. Among representatives of other engineering societies, or of +Government Bureaus, the membership of the National Advisory Board +includes other members of this Society, as follows: General William +Crozier, Frank T. Chambers, Professor W. K. Hatt, Richard L. +Humphrey, Robert W. Hunt, H. G. Kelley, Robert W. Lesley, John B. +Lober, Hunter McDonald, and Frederick H. Newell.</p> + +<p> +In view, therefore, of the important part taken both officially and +unofficially by members of this Society in the planning and organization +of this work, it seems proper to present a statement of the scope, +methods, and progress of these investigations. Whereas the Act governing +this work limits the testing and investigation of fuels and of +structural materials to those belonging to the United States, the +activities of the Federal Government in the use of these materials so +far exceeds that of any other single concern in the United States, that +the results cannot but be of great value to all engineers and to all +those engaged in engineering works.</p> + + +<h5 class = "smallcaps">Mine Accidents Investigations.</h5> + +<p> +<i>Organization, and Character of the Work.</i>—The mine rescue +investigations, carried on at the Federal testing station, at Pittsburg, +Pa., include five lines of attack:</p> + +<p> +1.—Investigations in the mines to determine the conditions leading +up to mine disasters, the presence and the relative explosibility of +mine gas and coal dust, and mine fires and means of preventing and +combating them.</p> + +<p> +2.—Tests to determine the relative safety, or otherwise, of the +various explosives used in coal mining, when ignited in the presence of +explosible mixtures of natural gas and air, or coal dust, or of +both.</p> + +<p> +3.—Tests to determine the conditions under which electric +equipment is safe in coal-mining operations.</p> + +<p> +<!--png194--> +<span class = "pagenum">194</span> +<a name = "page194"> </a> +4.—Tests to determine the safety of various types of mine lights +in the presence of inflammable gas, and their accuracy in detecting +small percentages of mine gas.</p> + +<p> +5.—Tests of the various artificial breathing apparatus, and the +training of miners and of skilled mining engineers in rescue +methods.</p> + +<p> +The first four of these lines of investigation have to do with +preventive measures, and are those on which ultimately the greatest +dependence must be placed. The fifth is one in which the result seems at +first to be the most apparent. It has to do, not with prevention, but +with the cure of conditions which should not arise, or, at least, should +be greatly ameliorated.</p> + +<p> +During the last 19 years, 28,514 men have been killed in the coal-mining +industries.<a class = "tag" name = "tag2" href = "#note2">2</a> In 1907 +alone, 3,125 men lost their lives in coal mines, and, in addition, +nearly 800 were killed in the metal mines and quarries of the country. +Including the injured, 8,441 men suffered casualties in the mines in +that year. In every mining camp containing 1,000 men, 4.86 were taken by +violent death in that year. In the mining of coal in Great Britain, 1.31 +men were killed in every 1,000 employed in the same year; in France, +1.1; in Belgium, 0.94, or less than 1 man in every 1,000 employed. It is +thus seen that from three to four times as many men are being killed in +the United States as in any European coal-producing country. This safer +condition in Europe has resulted from the use of safer explosives, or +the better use of the explosives available; from the reduction in the +use of open lights; from the establishment of mine rescue stations and +the training with artificial breathing apparatus; and from the adoption +of regulations for safeguarding the lives of the workmen.</p> + +<p> +The mining engineering field force of the Geological Survey, at the head +of which is Mr. George S. Rice, an experienced mining and consulting +engineer, has already made great progress in the study of underground +mining conditions and methods. Nearly all the more dangerous coal mines +in the United States have been examined; samples of gas, coal, and dust +have been taken and analyzed at the chemical laboratories at Pittsburg; +extended tests have been made as to the explosibility of various +mixtures of gas and air; as to the explosibility of dust from various +typical coals; as to the chemical composition and +<!--png195--> +<span class = "pagenum">195</span> +<a name = "page195"> </a> +physical characteristics of this dust; the degree of fineness necessary +to the most explosive conditions; and the methods of dampening the dust +by water, by humidifying, by steam, or of deadening its explosibility by +the addition of calcium chloride, stone dust, etc. A bulletin outlining +the results thus far obtained in the study of the coal-dust problem is +now in course of publication.<a class = "tag" name = "tag3" href = +"#note3">3</a></p> + +<p> +After reviewing the history of observations and experiments with coal +dust carried on in Europe, and later, the experiments at the French, +German, Belgian, and English explosives-testing stations, this bulletin +takes up the coal-dust question in the United States. Further chapters +concern the tests as to the explosibility of coal dust, made by the +Geological Survey, at Pittsburg; investigations, both at the Pittsburg +laboratory and in mines, as to the humidity of mine air. There is also a +chapter on the chemical investigations into the ignition of coal dust by +Dr. J. C. W. Frazer, of the Geological Survey. The application +of some of these data to actual mine conditions in Europe, in the last +year, is treated by Mr. Axel Larsen; the use of exhaust steam in a mine +of the Consolidation Coal Company, in West Virginia, is discussed by Mr. +Frank Haas, Consulting Engineer; and the use of sprays in Oklahoma coal +mines is the subject of a chapter by Mr. Carl Scholz, Vice-President of +the Rock Island Coal Mining Company.</p> + +<p> +An earlier bulletin setting forth the literature and certain mine +investigations of explosive gases and dust,<a class = "tag" name = +"tag4" href = "#note4">4</a> has already been issued. After treating of +methods of collecting and analyzing the gases found in mines, of +investigations as to the rate of liberation of gas from coal, and of +studies on coal dust, this bulletin discusses such factors as the +restraining influence of shale dust and dampness on coal-dust +explosions. It then takes up practical considerations as to the danger +of explosions, including the relative inflammability of old and fresh +coal dust. The problems involved are undergoing further investigation +and elaboration, in the light of information already gathered.</p> + +<p> +<i>Permissible Explosives.</i>—The most important progress in +these tests and investigations has been made in those relating to the +various explosives used in getting coal from mines. Immediately upon the +enactment of the first legislation, in the spring of 1908, arrangements +<!--png196--> +<span class = "pagenum">196</span> +<a name = "page196"> </a> +were perfected whereby the lower portion of the old Arsenal grounds +belonging to the War Department and adjacent to the Pennsylvania +Railroad, on the Alleghany River, at 40th and Butler Streets, Pittsburg, +Pa., were transferred to the Interior Department for use in these +investigations. Meantime, in anticipation of the appropriation, Mr. +Clarence Hall, an engineer experienced in the manufacture and use of +explosives, was sent to Europe to study the methods of testing +explosives practiced at the Government stations in Great Britain, +Germany, Belgium, and France. Mr. Joseph A. Holmes also visited Europe +for the purpose of studying methods of ameliorating conditions in the +mines. Three foreign mining experts, the chiefs of investigating bureaus +in Belgium, Germany, and England, spent three months studying conditions +in the United States at the invitation of the Secretary of the Interior, +to whom they submitted a valuable report.<a class = "tag" name = "tag5" +href = "#note5">5</a></p> + +<p> +Under the supervision of the writer, Chief Engineer of these +investigations, detailed plans and specifications had been prepared in +advance for the necessary apparatus and the transformation of the +buildings at Pittsburg to the purposes of this work. It was possible, +therefore, to undertake immediately the changes in existing buildings, +the erection of new buildings, the installation of railway tracks, +laboratories, and the plumbing, heating, and lighting plant, etc. This +work was carried on with unusual expedition, under the direction of the +Assistant Chief Engineer, Mr. James C. Roberts, and was completed within +a few months, by which time most of the apparatus was delivered and +installed.</p> + +<p> +One building (No. 17) is devoted to the smaller physical tests of +explosives. It was rendered fire resistant by heavily covering the +floors, ceiling, and walls with cement on metal lath, and otherwise +protecting the openings. In it are installed apparatus for determining +calorific value of explosives, pressure produced on ignition, +susceptibility to ignition when dropped, rate of detonation, length and +duration of flame, and kindred factors. Elsewhere on the grounds is a +gallery of boiler-steel plate, 100 ft. long and more than 6 ft. in +diameter, solidly attached to a mass of concrete at one end, in which is +embedded a cannon from which to discharge the explosive under test, and +open at the other end, and otherwise so constructed as to +<!--png199--> +<span class = "pagenum">197</span> +<a name = "page197"> </a> +simulate a small section of a mine gallery (Fig. 2, <a href = +"#plate_VI">Plate VI</a>). The heavy mortar pendulum, for the +pendulum test for determining the force produced by an explosive, is +near by, as is also an armored pit in which large quantities of +explosive may be detonated, with a view to studying the effects of +magazine explosions, and for testing as to the rate at which ignition of +an explosive travels from one end to the other of a cartridge, and the +sensitiveness of one cartridge to explosion by discharge of another +near by.</p> + +<p> +In another building (No. 21), is a well-equipped chemical laboratory for +chemical analyses and investigations of explosives, structural +materials, and fuels.</p> + +<p> +Several months were required to calibrate the various apparatus, and to +make analyses of the available natural gas to determine the correct +method of proportioning it with air, so as to produce exact mixtures of +2, 4, 6, or 8% of methane with air. Tests of existing explosives were +made in air and in inflammable mixtures of air and gas, with a view to +fixing on some standard explosive as a basis of comparison. Ultimately, +40% nitro-glycerine dynamite was adopted as the standard. Investigative +tests having been made, and the various factors concerning all the +explosives on the market having been determined, a circular was sent to +all manufacturers of explosives in the United States, on January 9th, +1909, and was also published in the various technical journals, through +the associated press, and otherwise.</p> + +<p> +On May 15th, 1909, all the explosives which had been offered for test, +as permissible, having been tested, the first list of permissible +explosives was issued, as given in the following circular:</p> + +<div class = "quotation section"> +<p> +“<span class = "smaller">EXPLOSIVES CIRCULAR NO. 1.</span></p> + +<h5>“DEPARTMENT OF THE INTERIOR.</h5> + +<h5 class = "smallcaps nospace">“United States Geological Survey.</h5> + +<h5 class = "smallcaps nospace">“May 15, 1909.</h5> + +<h5>“LIST OF PERMISSIBLE EXPLOSIVES.</h5> + +<h5 class = "nospace">“Tested prior to May 15, 1909.</h5> + +<p> +“As a part of the investigation of mine explosions authorized by +Congress in May, 1908, it was decided by the Secretary of the Interior +that a careful examination should be made of the various explosives used +in mining operations, with a view to determining the extent to +<!--png200--> +<span class = "pagenum">198</span> +<a name = "page198"> </a> +which the use of such explosives might be responsible for the occurrence +of these disasters.</p> + +<p> +“The preliminary investigation showed the necessity of subjecting to +rigid tests all explosives intended for use in mines where either gas or +dry inflammable dust is present in quantity or under conditions which +are indicative of danger.</p> + +<p> +“With this in view, a letter was sent by the Director of the United +States Geological Survey on January 9, 1909, to the manufacturers of +explosives in the United States, setting forth the conditions under +which these explosives would be examined and the nature of the tests to +which they would be subjected.</p> + +<p> +“Inasmuch as the conditions and tests described in this letter were +subsequently followed in testing the explosives given in the list below, +they are here reproduced, as follows:</p> + +<p> +“(1) The manufacturer is to furnish 100 pounds of each explosive which +he desires to have tested; he is to be responsible for the care, +handling, and delivery of this material at the testing station on the +United States arsenal grounds, Fortieth and Butler streets, Pittsburg, +Pa., at the time the explosive is to be tested; and he is to have a +representative present during the tests, who will be responsible for the +handling of the packages containing the explosives until they are opened +for testing.</p> + +<p> +“(2) No one is to be present at or to participate in these tests except +the necessary government officers at the testing station, their +assistants, and the representative of the manufacturer of the explosives +to be tested.</p> + +<p> +“(3) The tests will be made in the order of the receipt of the +applications for them, provided the necessary quantity of the explosive +is delivered at the plant by the time assigned, of which due notice will +be given by the Geological Survey.</p> + +<p> +“(4) Preference will be given to the testing of explosives that are now +being manufactured and that are in that sense already on the market. No +test will be made of any new explosive which is not now being +manufactured and marketed, until all explosives now on the market that +may be offered for testing have been tested.</p> + +<p> +“(5) A list of the explosives which pass certain requirements +satisfactorily will be furnished to the state mine inspectors, and will +be made public in such further manner as may be considered +desirable.</p> + +<h6>“TEST REQUIREMENTS FOR EXPLOSIVES.</h6> + +<p> +“The tests will be made by the engineers of the United States Explosives +Testing Station at Pittsburg, Pa., in gas and dust gallery No. 1. The +charge of explosive to be fired in tests 1, 2, and 3 shall be equal in +disruptive power to one-half pound (227 grams) of 40 per cent. +nitroglycerin dynamite in its original wrapper, of the following +formula:</p> + +<table class = "inline quotation"> +<tr> +<td>Nitroglycerin</td> +<td class = "number">40</td> +</tr> +<tr> +<td>Nitrate of sodium</td> +<td class = "number">44</td> +</tr> +<tr> +<td>Wood pulp</td> +<td class = "number">15</td> +</tr> +<tr> +<td>Calcium carbonate</td> +<td class = "number underline">1</td> +</tr> +<tr> +<td></td><td class = "number">100</td> +</tr> +</table> + +<p> +<!--png201--> +<span class = "pagenum">199</span> +<a name = "page199"> </a> +“Each charge shall be fired with an electric fuse of sufficient power to +completely detonate or explode the charge, as recommended by the +manufacturer. The explosive must be in such condition that the chemical +and physical tests do not show any unfavorable results. The explosives +in which the charge used is less than 100 grams (0.22 pound) will be +weighed in tinfoil without the original wrapper.</p> + +<p> +“The dust used in tests 2, 3, and 4 will be of the same degree of +fineness and taken from one mine.<a class = "tag" name = "tag6" href = +"#note6">6</a></p> + +<p> +“<span class = "smallcaps">Test 1.</span>—Ten shots with the +charge as described above, in its original wrapper, shall be fired, each +with 1 pound of clay tamping, at a gallery temperature of 77° F., into a +mixture of gas and air containing 8 per cent. of methane and ethane. An +explosive will pass this test if all ten shots fail to ignite the +mixture.</p> + +<p> +“<span class = "smallcaps">Test 2.</span>—Ten shots with charge as +previously noted, in its original wrapper, shall be fired, each with 1 +pound of clay tamping at a gallery temperature of 77° F., into a mixture +of gas and air containing 4 per cent. of methane and ethane and 20 +pounds of bituminous coal dust, 18 pounds of which is to be placed on +shelves laterally arranged along the first 20 feet of the gallery, and 2 +pounds to be placed near the inlet of the mixing system in such a manner +that all or part of it will be suspended in the first division of the +gallery. An explosive will pass this test if all ten shots fail to +ignite the mixture.</p> + +<p> +“<span class = "smallcaps">Test 3.</span>—Ten shots with charge as +previously noted, in its original wrapper, shall be fired, each with 1 +pound of clay tamping at a gallery temperature of 77° F., into 40 pounds +of bituminous coal dust, 20 pounds of which is to be distributed +uniformly on a horse placed in front of the cannon and 20 pounds placed +on side shelves in sections 4, 5, and 6. An explosive will pass this +test if all ten shots fail to ignite the mixture.</p> + +<p> +“<span class = "smallcaps">Test 4.</span>—A limit charge will be +determined within 25 grams by firing charges in their original wrappers, +untamped, at a gallery temperature of 77° F., into a mixture of gas and +air containing 4 per cent. of methane and ethane and 20 pounds of +bituminous coal dust, to be arranged in the same manner as in test 2. +This limit charge is to be repeated five times under the same conditions +before being established.</p> + +<p> +“<span class = "smallcaps">Note.</span>—At least 2 pounds of clay +tamping will be used with slow-burning explosives.</p> + +<p> +“<span class = "smallcaps">Washington, D. C.</span>, <i>January 9, +1909</i>.</p> + +<p class = "space"> +“In response to the above communication applications were received from +12 manufacturers for the testing of 29 explosives. Of these explosives, +the 17 given in the following list have passed all the test requirements +set forth, and will be termed permissible explosives.</p> + +<h5 class = "ital"> +“Permissible explosives tested prior to May 15, 1909.</h5> + +<table class = "quotation lines"> +<tr class = "lines"> +<th>Brand.</th> +<th class = "leftline">Manufacturer.</th> +</tr> + +<tr> +<td>Ætna coal powder A</td> +<td class = "leftline">Ætna Powder Co., Chicago, Ill.</td> +</tr> +<tr> +<td>Ætna coal powder B</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td>Carbonite No. 1</td> +<td class = "leftline"><div class = "hanging"> +E. I. Dupont de Nemours Powder Co., Wilmington, Del.</div></td> +</tr> +<tr> +<td> +<!--png202--> +<span class = "pagenum">200</span> +<a name = "page200"> </a> +Carbonite No. 2</td> +<td class = "leftline"><div class = "hanging"> +E. I. Du Pont de Nemours Powder Co., Wilmington, Del.</div></td> +</tr> +<tr> +<td>Carbonite No. 3</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td>Carbonite No. 1 L. F.</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td>Carbonite No. 2 L. F.</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td>Coal special No. 1</td> +<td class = "leftline">Keystone Powder Co., Emporium, Pa.</td> +</tr> +<tr> +<td>Coal special No. 2</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td>Coalite No. 1</td> +<td class = "leftline">Potts Powder Co., New York City.</td> +</tr> +<tr> +<td>Coalite No. 2 D</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td>Collier dynamite No. 2</td> +<td class = "leftline">Sinnamahoning Powder Co., Emporium, Pa.</td> +</tr> +<tr> +<td>Collier dynamite No. 4</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td>Collier dynamite No. 5</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td>Masurite M. L. F.</td> +<td class = "leftline">Masurite Explosive Co., Sharon, Pa.</td> +</tr> +<tr> +<td>Meteor dynamite</td> +<td class = "leftline"><div class = "hanging"> +E. I. Du Pont de Nemours Powder Co., Wilmington, Del.</div></td> +</tr> +<tr> +<td>Monobel</td> +<td class = "leftline middle">Do.</td> +</tr> +</table> + +<p> +“Subject to the conditions named below, a permissible explosive is +defined as an explosive which has passed gas and dust gallery tests Nos. +1, 2, and 3 as described above, and of which in test No. 4 1½ pounds +(680 grams) of the explosive has been fired into the mixture there +described without causing an ignition.</p> + +<p> +“<i>Provided:</i></p> + +<p> +“1. That the explosive is in all respects similar to the sample +submitted by the manufacturer for test.</p> + +<p> +“2. That double-strength detonators are used of not less strength than 1 +gram charge consisting by weight of 90 parts of mercury fulminate and 10 +parts of potassium chlorate (or its equivalent), except for the +explosive ‘Masurite M. L. F.’ for which the detonator shall be +of not less strength than 1½ grams charge.</p> + +<p> +“3. That the explosive, if in a frozen condition, shall be thoroughly +thawed in a safe and suitable manner before use.</p> + +<p> +“4. That the amount used in practice does not exceed 1½ pounds (680 +grams) properly tamped.</p> + +<p> +“The above partial list includes the permissible explosives that have +passed these tests prior to May 15, 1909. The announcement of the +passing of like tests by other explosives will be made public +immediately after the completion of the tests for such explosives.</p> + +<p> +“A description of the method followed in making these and the many +additional tests to which each explosive is subjected, together with the +full data obtained in each case, will be published by the Survey at an +early date.</p> + +<!--png203--> +<span class = "pagenum">201</span> +<a name = "page201"> </a> +<h6>“NOTES AND SUGGESTIONS.</h6> + +<p> +“It may be wise to point out in this connection certain differences +between the permissible explosives as a class and the black powders now +so generally used in coal mining, as follows:</p> + +<p> +“(<i>a</i>) With equal quantities of each, the flame of the black powder +is more than three times as long and has a duration three thousand to +more than four thousand times that of one of the permissible explosives, +also the rate of explosion is slower.</p> + +<p> +“(<i>b</i>) The permissible explosives are one and one-fourth to one and +three-fourths times as strong and are said, if properly used, to do +twice the work of black powder in bringing down coal; hence only half +the quantity need be used.</p> + +<p> +“(<i>c</i>) With 1 pound of a permissible explosive or 2 pounds of black +powder, the quantity of noxious gases given off from a shot averages +approximately the same, the quantity from the black powder being less +than from some of the permissible explosives and slightly greater than +from others. The time elapsing after firing before the miner returns to +the working face or fires another shot should not be less for +permissible explosives than for black powder.</p> + +<p> +“The use of permissible explosives should be considered as supplemental +to and not as a substitute for other safety precautions in mines where +gas or inflammable coal dust is present under conditions indicative of +danger. As stated above, they should be used with strong detonators; and +the charge used in practice should not exceed 1½ pounds, and in many +cases need not exceed 1 pound.</p> + +<p> +“Inasmuch as no explosive manufactured for use in mining is flameless, +and as no such explosive is entirely safe under all the variable mining +conditions, the use of the terms ‘flameless’ and ‘safety’ as applied to +explosives is likely to be misunderstood, may endanger human life, and +should be discouraged.</p> + +<p align = "right"> +“<span class = "smallcaps">Joseph A. Holmes</span>, +<span class = "padding"> </span><br> +“<i>Expert in Charge Technologic Branch</i>.</p> + +<p> +“Approved, May 18, 1909:<br> +<span class = "padding"> </span> +“<span class = "smallcaps">Geo. Otis Smith</span>,<br> +<span class = "padding"> </span> +<span class = "padding"> </span> +“<i>Director</i>.”</p> +</div> + +<p> +In the meantime, many of the explosives submitted, which heretofore had +been on the market as safety explosives, were found to be unsafe for use +in gaseous or dusty mines, and the manufacturers were permitted to +withdraw them. Their weaknesses being known, as a result of these tests, +the manufacturers were enabled to produce similar, but safer, +explosives. Consequently, applications for further tests continued to +pour in, as they still do, and on October 1st, 1909, a second list of +permissible explosives was issued, as follows:</p> + +<div class = "quotation section"> +<p> +<!--png204--> +<span class = "pagenum">202</span> +<a name = "page202"> </a> +“<span class = "smaller">EXPLOSIVES CIRCULAR NO. 2.</span></p> + +<h5>“DEPARTMENT OF THE INTERIOR.</h5> + +<h5 class = "smallcaps nospace">“United States Geological Survey.</h5> + +<h5 class = "smallcaps nospace">October 1, 1909.</h5> + +<h5>“LIST OF PERMISSIBLE EXPLOSIVES.</h5> + +<h5 class = "nospace">“Tested prior to October 1, 1909.</h5> + +<p> +“The following list of permissible explosives tested by the United +States Geological Survey at Pittsburg, Pa., is hereby published for the +benefit of operators, mine owners, mine inspectors, miners, and others +interested.</p> + +<p> +“The conditions and test requirements described in Explosives Circular +No. 1, issued under date of May 15, 1909, have been followed in all +subsequent tests.</p> + +<p> +“Subject to the provisions named below, a permissible explosive is +defined as an explosive which is in such condition that the chemical and +physical tests do not show any unfavorable results; which has passed gas +and dust gallery tests Nos. 1 and 3, as described in circular No. 1; and +of which, in test No. 4, 1½ pounds (680 grams) has been fired into the +mixture there described without causing ignition.</p> + +<p> +“<i>Permissible explosives tested prior to October 1, 1909.</i></p> + +<p> +“[Those reported in Explosives Circular No. 1 are marked *.]</p> + +<table class = "quotation lines"> +<tr class = "lines"> +<th>Brand.</th> +<th class = "leftline">Manufacturer.</th> +</tr> + +<tr> +<td>* Ætna coal powder A</td> +<td class = "leftline">Ætna Powder Co., Chicago, Ill.</td> +</tr> +<tr> +<td> Ætna coal powder AA</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td>* Ætna coal powder B</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td> Ætna coal powder C</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td> Bituminite No. 1</td> +<td class = "leftline">Jefferson Powder Co., Birmingham, Ala.</td> +</tr> +<tr> +<td> Black Diamond No. 3</td> +<td class = "leftline"><div class = "hanging"> +Illinois Powder Manufacturing Co., St. Louis, Mo.</div></td> +</tr> +<tr> +<td> Black Diamond No. 4</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td>* Carbonite No. 1</td> +<td class = "leftline"><div class = "hanging"> +E. I. Du Pont de Nemours Powder Co., Wilmington, Del.</div></td> +</tr> +<tr> +<td>* Carbonite No. 2</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td>* Carbonite No. 3</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td>* Carbonite No. 1-L. F.</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td>* Carbonite No. 2-L. F.</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td>* Coalite No. 1</td> +<td class = "leftline">Potts Powder Co., New York City.</td> +</tr> +<tr> +<td>* Coalite No. 2-D.</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td>* Coal special No. 1</td> +<td class = "leftline">Keystone Powder Co., Emporium, Pa.</td> +</tr> +<tr> +<td>* Coal special No. 2</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td> +<!--png205--> +<span class = "pagenum">203</span> +<a name = "page203"> </a> +* Collier dynamite No. 2.</td> +<td class = "leftline"><div class = "hanging"> +Sinnamahoning Powder Manufacturing Co., Emporium, Pa.</div></td> +</tr> +<tr> +<td>* Collier dynamite No. 4.</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td>* Collier dynamite No. 5.</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td> Giant A low-flame dynamite.</td> +<td class = "leftline">Giant Powder Co. (Con.), Giant, Cal.</td> +</tr> +<tr> +<td> Giant B low-flame dynamite.</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td> Giant C low-flame dynamite.</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td>* Masurite M. L. F.</td> +<td class = "leftline">Masurite Explosives Co., Sharon, Pa.</td> +</tr> +<tr> +<td>* Meteor dynamite.</td> +<td class = "leftline"><div class = "hanging"> +E. I. Du Pont de Nemours Powder Co., Wilmington, Del.</div></td> +</tr> +<tr> +<td> Mine-ite A.</td> +<td class = "leftline">Burton Powder Co., Pittsburg, Pa.</td> +</tr> +<tr> +<td> Mine-ite B.</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td>* Monobel.</td> +<td class = "leftline"><div class = "hanging"> +E. I. Du Pont de Nemours Powder Co., Wilmington, Del.</div></td> +</tr> +<tr> +<td> Tunnelite No. 5.</td> +<td class = "leftline"><div class = "hanging"> +G. R. McAbee Powder and Oil Co., Pittsburg, Pa.</div></td> +</tr> +<tr> +<td> Tunnelite No. 6.</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td> Tunnelite No. 7.</td> +<td class = "leftline middle">Do.</td> +</tr> +<tr> +<td> Tunnelite No. 8.</td> +<td class = "leftline middle">Do.</td> +</tr> +</table> + +<p> +“<i>Provided:</i></p> + +<p> +“1. That the explosive is in all respects similar to sample submitted by +the manufacturer for test.</p> + +<p> +“2. That No. 6 detonators, preferably No. 6 electric detonators (double +strength), are used of not less strength than 1 gram charge, consisting +by weight of 90 parts of mercury fulminate and 10 parts of potassium +chlorate (or its equivalent), except for the explosive ‘Masurite +M. L. F.,’ for which the detonator shall be of not less strength +than 1½ grams charge.</p> + +<p> +“3. That the explosive, if frozen, shall be thoroughly thawed in a safe +and suitable manner before use.</p> + +<p> +“4. That the amount used in practice does not exceed 1½ pounds (680 +grams), properly tamped.</p> + +<p> +“The above partial list includes all the permissible explosives that +have passed these tests prior to October 1, 1909. The announcement of +the passing of like tests by other explosives will be made public +immediately after the completion of the tests.</p> + +<p> +“With a view to the wise use of these explosives it may be well in this +connection to point out again certain differences between the +permissible explosives as a class and the black powders now so generally +used in coal mining, as follows:</p> + +<p> +“(<i>a</i>) With equal quantities of each, the flame of the black powder +is more than three times as long and has a duration three thousand to +<!--png206--> +<span class = "pagenum">204</span> +<a name = "page204"> </a> +more than four thousand times that of one of the permissible explosives; +the rate of explosion also is slower.</p> + +<p> +“(<i>b</i>) The permissible explosives are one and one-fourth to one and +three-fourths times as strong and are said, if properly used, to do +twice the work of black powder in bringing down coal; hence only half +the quantity need be used.</p> + +<p> +“(<i>c</i>) With 1 pound of a permissible explosive or 2 pounds of black +powder, the quantity of noxious gases given off from a shot averages +approximately the same, the quantity from the black powder being less +than from some of the permissible explosives and slightly greater than +from others. The time elapsing after firing before the miner returns to +the working face or fires another shot should not be less for +permissible explosives than for black powder.</p> + +<p> +“The use of permissible explosives should be considered as supplemental +to and not as a substitute for other safety precautions in mines where +gas or inflammable coal dust is present under conditions indicating +danger. As stated above, they should be used with strong detonators, and +the charge used in practice should not exceed 1½ pounds and in many +cases need not exceed 1 pound.</p> + +<p align = "right"> +“<span class = "smallcaps">Joseph A. Holmes</span>, +<span class = "padding"> </span><br> +“<i>Expert in Charge Technologic Branch</i>.</p> + +<p>“Approved, October 11, 1909.<br> +<span class = "padding"> </span> +“<span class = "smallcaps">H. C. Rizer</span>,<br> +<span class = "padding"> </span> +<span class = "padding"> </span> +“<i>Acting Director.</i>”</p> +</div> + +<p> +The second list contains 31 explosives which the Government is prepared +to brand as permissible, and therefore comparatively safe, for use in +gaseous and dusty mines. An equally large number of so-called safety +powders failed to pass these tests. Immediately on the passing of the +tests, as to the permissibility of any explosive, the facts are reported +to the manufacturer and to the various State mine inspectors. When +published, the permissible lists were issued to all explosives +manufacturers, all mine operators in the United States, and State +inspectors. The effect has been the enactment, by three of the largest +coal-producing States, of legislation or regulations prohibiting the use +of any but permissible explosives in gaseous or dusty mines, and other +States must soon follow. To prevent fraud, endeavor is being made to +restrict the use of the brand “Permissible Explosive, U. S. Testing +Station, Pittsburg, Pa.,” to only such boxes or packages as contain +listed permissible explosives.</p> + +<p> +As these tests clearly demonstrate, both in the records thereof and +visually to such as follow them, that certain explosives, especially +<!--png207--> +<span class = "pagenum">205</span> +<a name = "page205"> </a> +those which are slow-burning like black powder, or produce high +temperature in connection with comparative slow burning, will ignite +mixtures of gas and air, or mixtures of coal dust and air, and cause +explosions. The results point out clearly to all concerned, the danger +of using such explosives. The remedy is also made available by the +announcement of the names of a large number of explosives now on the +market at reasonable cost, which will not cause explosions under these +conditions. It is believed that when permissible explosives are +generally adopted in coal mines, this source of danger will have been +greatly minimized.</p> + +<p> +<i>Explosives Investigations.</i>—Questions have arisen on the +part of miners or of mine operators as to the greater cost in using +permissible explosives due to their expense, which is slightly in excess +of that of other explosives; as to their greater shattering effect in +breaking down the coal, and in giving a smaller percentage of lump and a +larger percentage of slack; and as to the possible danger of breathing +the gases produced.</p> + +<p> +Observations made in mines by Mr. J. J. Rutledge, an experienced +coal miner and careful mining engineer connected with the Geological +Survey, as to the amount of coal obtained by the use of permissible and +other explosives, tend to indicate that the permissible explosives are +not more, but perhaps less expensive than others, in view of the fact +that, because of their greater relative power, a smaller quantity is +required to do the work than is the case, say, with black powder. On the +other hand, for safety and for certainty of detonation, stronger +detonators are recommended for use with permissible explosives, +preferably electric detonators. These may cost a few cents more per +blast than the squib or fuse, but there is no danger that they will +ignite the gas, and the difference in cost is, in some measure, offset +by the greater certainty of action and the fact that they produce a much +more powerful explosion, thus again permitting the use of still smaller +quantities of the explosive and, consequently, reducing the cost. These +investigations are still in progress.</p> + +<p> +Concerning the shattering of the coal: This is being remedied in some of +the permissible explosives by the introduction of dopes, moisture, or +other means of slowing down the disruptive effect, so as to produce the +heaving and breaking effect obtained with the slower-burning powders +instead of the shattering effect produced by +<!--png208--> +<span class = "pagenum">206</span> +<a name = "page206"> </a> +dynamite. There is every reason to believe that as the permissible +explosives are perfected, and as experience develops the proper methods +of using them, this difficulty will be overcome in large measure. This +matter is also being investigated by the Survey mining engineers and +others, by the actual use of such explosives in coal-mining +operations.</p> + +<p> +Of the gases given off by explosives, those resulting from black powder +are accompanied by considerable odor and smoke, and, consequently, the +miners go back more slowly after the shots, allowing time for the gases +to be dissipated by the ventilation. With the permissible explosive, the +miner, seeing no smoke and observing little odor, is apt to be +incautious, and to think that he may run back immediately. As more is +learned of the use of these explosives, this source of danger, which is, +however, inconsiderable, will be diminished. Table 1 gives the +percentages of the gaseous products of combustions from equal weights of +black powder and two of the permissible explosives. Of the latter, one +represents the maximum amount of injurious gases, and the other the +minimum amount, between which limits the permissible explosives +approximately vary.</p> + +<p> +Such noxious gases as may be produced by the discharge of the explosive +are diluted by a much larger volume of air, and are practically +harmless, as proven by actual analysis of samples taken at the face +immediately after a discharge.</p> + +<h5>TABLE 1.</h5> + +<table class = "lines"> +<tr class = "lines"> +<td rowspan = "2"></td> +<th rowspan = "2" class = "leftline">Black<br> +powder.</th> +<th colspan = "2" class = "leftline"> +<span class = "smallcaps">Permissible Explosives.</span></th> +</tr> +<tr class = "lines"> +<th class = "leftline">Maximum.</th> +<th class = "leftline">Minimum.</th> +</tr> + +<tr> +<td>CO<sub>2</sub></td> +<td class = "middle leftline">22.8</td> +<td class = "middle leftline">14.50</td> +<td class = "middle leftline">21.4</td> +</tr> +<tr> +<td>CO</td> +<td class = "middle leftline">10.3</td> +<td class = "middle leftline">27.74</td> +<td class = "middle leftline"> 1.3</td> +</tr> +<tr> +<td>N</td> +<td class = "middle leftline">10.3</td> +<td class = "middle leftline">45.09</td> +<td class = "middle leftline">74.4</td> +</tr> +</table> + +<p> +In addition to investigations as to explosives for use in coal mining, +the Explosives Section of the Geological Survey analyzes and tests all +such materials, fuses, caps, etc., purchased by the Isthmian Canal +Commission, as well as many other kinds used by the Government. It is +thus acquiring a large fund of useful information, which will be +published from time to time, relative to the kinds of explosives +<!--png209--> +<span class = "pagenum">207</span> +<a name = "page207"> </a> +and the manner of using them best suited to any blasting operations, +either above or under water, in hard rock, earth, or coal. There has +been issued from the press, recently, a primer of explosives,<a class = +"tag" name = "tag7" href = "#note7">7</a> by Mr. Clarence Hall, the +engineer in charge of these tests, and Professor C. E. Munroe, +Consulting Explosives Chemist, which contains a large amount of valuable +fundamental information, so simply expressed as to be easily +understandable by coal miners, and yet sufficiently detailed to be a +valuable guide to all persons who have to handle or use explosives.</p> + +<p> +In the first chapters are described the various combustible substances, +and the chemical reactions leading to their explosibility. The low and +high explosives are differentiated, and the sensitiveness of fulminate +of mercury and other detonators is clearly pointed out. The various +explosives, such as gunpowder, black blasting powder, potassium chlorate +powders, nitro-glycerine powders, etc., are described, and their +peculiarities and suitability for different purposes are set forth. The +character and method of using the different explosives, both in opening +up work and in enclosed work in coal mines, follow, with information as +to the proper method of handling, transporting, storing, and thawing the +same. Then follow chapters on squibs, fuses, and detonators; on methods +of shooting coal off the solid; location of bore-holes; undercutting; +and the relative advantages of small and large charges, with +descriptions of proper methods of loading and firing the same. The +subjects of explosives for blasting in rock, firing machines, blasting +machines, and tests thereof, conclude the report.</p> + +<p> +The work of the chemical laboratory in which explosives are analyzed, +and in which mine gases and the gases produced by combustion of +explosives and explosions of coal-gas or coal dust are studied, has been +of the most fundamental and important character. The Government is +procuring a confidential record of the chemical composition and mode of +manufacture of all explosives, fuses, etc., which are on the market. +This information cannot but add greatly to the knowledge as to the +chemistry of explosives for use in mines, and will furnish the basis on +which remedial measures may be devised.</p> + +<p> +A bulletin (shortly to go to press) which gives the details of the +physical tests of the permissible explosives thus far tested, will set +<!--png210--> +<span class = "pagenum">208</span> +<a name = "page208"> </a> +forth elaborately the character of the testing apparatus, and the method +of use and of computing results.<a class = "tag" name = "tag8" href = +"#note8">8</a></p> + +<p> +This bulletin contains a chapter, by Mr. Rutledge, setting forth in +detail the results of his observations as to the best methods of using +permissible explosives in getting coal from various mines in which they +are used. This information will be most valuable in guiding mining +engineers who desire to adopt the use of permissible explosives, as to +the best methods of handling them.</p> + +<p> +<i>Electricity in Mines.</i>—In connection with the use of +electricity in mines, an informal series of tests has been made on all +enclosed electric fuses, as to whether or not they will ignite an +explosive mixture of air and gas when blown out. The results of this +work, which is under the direction of Mr. H. H. Clark, Electrical +Engineer for Mines, have been furnished the manufacturers for their +guidance in perfecting safer fuses, a series of tests of which has been +announced. A series of tests as to the ability of the insulation of +electric wiring to withstand the attacks of acid mine waters is in +progress, which will lead, it is hoped, to the development of more +permanent and cheaper insulation for use in mine wiring. A series of +competitive tests of enclosed motors for use in mines has been +announced, and is in progress, the object being to determine whether or +not sparking from such motors will cause an explosion in the presence of +inflammable gas.</p> + +<p> +In the grounds outside of Building No. 10 is a large steel gallery, much +shorter than Gallery No. 1, in fact, but 30 ft. in length, and much +greater in diameter, namely, 10 ft. (Fig. 3, <a href = +"#plate_X">Plate X</a>), in which electric motors, electric cutting +machines, and similar apparatus, are being tested in the presence of +explosive mixtures of gas and dust and with large amperage and high +voltage, such as may be used in the largest electrical equipment in +mines.</p> + +<p> +The investigation as to the ability of insulation to withstand the +effects of acid mine waters has been very difficult and complicated. At +first it was believed possible that mine waters from nearby Pennsylvania +mines and of known percentages of acidity could be procured and kept in +an immersion tank at approximately any given percentage of strength. +This was found to be impracticable, as these waters seem to undergo +rapid change the moment they are exposed to the air or are transported, +in addition to the changes wrought by evaporation +<!--png211--> +<span class = "pagenum">209</span> +<a name = "page209"> </a> +in the tank. It has been necessary, therefore, to analyze and study +carefully these waters with a view to reproducing them artificially for +the purpose of these tests. Concerning the insulation, delicate +questions have arisen as to a standard of durability which shall be +commensurate with reasonable cost. These preliminary points are being +solved in conference with the manufacturers, and it is expected that the +results will soon permit of starting the actual tests.</p> + +<p> +<i>Safety-Lamp Investigations.</i>—Many so-called safety lamps are +on the market, and preliminary tests of them have been made in the lamp +gallery, in Building No. 17 (Fig. 2, <a href = +"#plate_X">Plate X</a>). After nearly a year of endeavor to +calibrate this gallery, and to co-ordinate its results with those +produced in similar galleries in Europe, this preliminary inquiry has +been completed, and the manufacturers and agents of all safety lamps +have been invited to be present at tests of their products at the +Pittsburg laboratory.</p> + +<p> +A circular dated November 19th, 1909, contains an outline of these +tests, which are to be conducted under the direction of Mr. J. W. +Paul, an experienced coal-mining engineer and ex-Chief of the Department +of State Mine Inspection of West Virginia. The lamps will be subjected +to the following tests:</p> + +<p> +(<i>a</i>).—Each lamp will be placed in a mixture of air and +explosive natural gas containing 6, 8, and 10% of gas, moving at a +velocity of from 200 to 2,500 ft. per min., to determine the velocity of +the air current which will ignite the mixture surrounding the lamp. The +current will be made to move against the lamp in a horizontal, vertical +ascending, and vertical descending direction, and at an angle of 45°, +ascending and descending.</p> + +<p> +(<i>b</i>).—After completing the tests herein described, the lamps +will be subjected to the tests described under (<i>a</i>), with the air +and gas mixture under pressure up to 6 in. of water column.</p> + +<p> +(<i>c</i>).—Under the conditions outlined in (<i>a</i>), coal dust +will be introduced into the current of air and gas to determine its +effect, if any, in inducing the ignition of the gas mixture.</p> + +<p> +(<i>d</i>).—Each lamp will be placed in a mixture of air and +varying percentages of explosive natural gas to determine the action of +the gas on the flame of the lamp.</p> + +<p> +(<i>e</i>).—Each lamp will be placed in a mixture of air and +varying percentages of carbonic acid gas to determine the action of the +gas on the flame.</p> + +<p> +<!--png212--> +<span class = "pagenum">210</span> +<a name = "page210"> </a> +(<i>f</i>).—Lamps equipped with internal igniters will be placed +in explosive mixtures of air and gas in a quiet state and in a moving +current, and the effect of the igniter on the surrounding mixture will +be observed.</p> + +<p> +(<i>g</i>).—The oils (illuminants) used in the lamps will be +tested as to viscosity, gravity, flashing point, congealing point, and +composition.</p> + +<p> +(<i>h</i>).—Safety-lamp globes will be tested by placing each +globe in position in the lamp and allowing the flame to impinge against +the globe for 3 min. after the lamp has been burning with a full flame +for 10 min., to determine whether the globe will break.</p> + +<p> +(<i>i</i>).—Each safety-lamp globe will be mounted in a lighted +lamp with up-feed, and placed for 5 min. in an explosive mixture of air +and gas moving at the rate of 1,000 ft. per min., to determine whether +the heat will break the glass and, if it is broken, to note the +character of the fracture.</p> + +<p> +(<i>j</i>).—Safety-lamp globes will be broken by impact, by +allowing each globe to fall and strike, horizontally, on a block of +seasoned white oak, the distance of fall being recorded.</p> + +<p> +(<i>k</i>).—Each safety lamp globe will be mounted in a safety +lamp and, when the lamp is in a horizontal position, a steel pick +weighing 100 grammes will be permitted to fall a sufficient distance to +break the globe by striking its center, the distance of the fall to be +recorded.</p> + +<p> +(<i>l</i>).—To determine the candle power of safety lamps, a +photometer equipped with a standardized lamp will be used. The +candle-power will be determined along a line at right angles to the axis +of the flame; also along lines at angles to the axis of the flame both +above and below the horizontal. The candle-power will be read after the +lamp has been burning 20 min.</p> + +<p> +(<i>m</i>).—The time a safety lamp will continue to burn with a +full charge of illuminant will be determined.</p> + +<p> +(<i>n</i>).—Wicks in lamps must be of sufficient length to be at +all times in contact with the bottom of the vessel in which the +illuminant is contained, and, before it is used, the wick shall be dried +to remove moisture.</p> + +<p> +<i>Mine-Rescue Methods.</i>—Mr. Paul, who has had perhaps as wide +an experience as any mining man in the investigation of and in rescue +work at mine disasters, is also in charge of the mine-rescue +<!--png213--> +<span class = "pagenum">211</span> +<a name = "page211"> </a> +apparatus and training for the Geological Survey. These operations +consist chiefly of a thorough test of the various artificial breathing +apparatus, or so-called oxygen helmets. Most of these are of European +make and find favor in Great Britain, Belgium, France, or Germany, +largely according as they are of domestic design and manufacture. As yet +nothing has been produced in the United States which fulfills all the +requirements of a thoroughly efficient and safe breathing apparatus for +use in mine disasters.</p> + +<p> +At the Pittsburg testing station there are a number of all kinds of +apparatus. The tests of these are to determine ease of use, of repair, +durability, safety under all conditions, period during which the supply +of artificial air or oxygen can be relied on, and other essential +data.</p> + +<p> +In addition to the central testing station, sub-stations for training +miners, and as headquarters for field investigation as to the causes of +mine disasters and for rescue work in the more dangerous coal fields, +have been established; at Urbana, Ill., in charge of Mr. R. Y. +Williams, Mining Engineer; at Knoxville, Tenn., in charge of Mr. +J. J. Rutledge, Mining Engineer; at McAlester, Okla., in charge of +Mr. L. M. Jones, Assistant Mining Engineer; and at Seattle, Wash., +in charge of Mr. Hugh Wolflin, Assistant Mining Engineer. Others may +soon be established in Colorado and elsewhere, in charge of skilled +mining engineers who have been trained in this work at Pittsburg, and +who will be assisted by trained miners. It is not to be expected that +under any but extraordinary circumstances, such as those which occurred +at Cherry, Ill., the few Government engineers, located at widely +scattered points throughout the United States, can hope to save the +lives of miners after a disaster occurs. As a rule, all who are alive in +the mine on such an occasion, are killed within a few hours. This is +almost invariably the case after a dust explosion, and is likely to be +true after a gas explosion, although a fire such as that at Cherry, +Ill., offers the greatest opportunity for subsequent successful rescue +operations. The most to be hoped for from the Government engineers is +that they shall train miners and be available to assist and advise State +inspectors and mine owners, should their services be +called for.</p> + +<p> +It should be borne in mind that the Federal Government has no +<!--png214--> +<span class = "pagenum">212</span> +<a name = "page212"> </a> +police duties in the States, and that, therefore, its employees may not +direct operations or have other responsible charge in the enforcement of +State laws. There is little reason to doubt that these Federal mining +engineers, both because of their preliminary education as mining +engineers and their subsequent training in charge of mine operations, +and more recently in mine-accidents investigations and rescue work, are +eminently fitted to furnish advice and assistance on such occasions. The +mere fact that, within a year, some of these men have been present at, +and assisted in, rescue work or in opening up after disasters at nearly +twenty of such catastrophes, whereas the average mining engineer or +superintendent may be connected with but one in a lifetime, should make +their advice and assistance of supreme value on such occasions. They +cannot be held in any way responsible for tardiness, however, nor be +unduly credited with effective measures taken after a mine disaster, +because of their lack of responsible authority or charge, except in +occasional instances where such may be given them by the mine owners or +the State officials, from a reliance on their superior equipment for +such work.</p> + +<p> +Successful rescue operations may only be looked for when the time, now +believed to be not far distant, has been reached when the mine operators +throughout the various fields will have their own rescue stations, as is +the practice in Europe, and have available, at certain strategic mines, +the necessary artificial breathing apparatus, and have in their employ +skilled miners who have been trained in rescue work at the Government +stations. Then, on the occurrence of a disaster, the engineer in charge +of the Government station may advise by wire all those who have proper +equipment or training to assemble, and it may be possible to gather, +within an hour or two of a disaster, a sufficiently large corps of +helmet-men to enable them to recover such persons as have not been +killed before the fire—which usually is started by the +explosion—has gained sufficient headway to prevent entrance into +the mine. Without such apparatus, it is essential that the fans be +started, and the mine cleared of gas. The usual effect of this is to +give life to any incipient fire. With the apparatus, the more dense the +gas, the safer the helmet-men are from a secondary explosion or from the +rapid ignition of a fire, because of the absence of the oxygen necessary +to combustion.</p> + +<p> +The miners who were saved at Cherry, Ill., on November 20th, +<!--png215--> +<span class = "pagenum">213</span> +<a name = "page213"> </a> +1909, owe their lives primarily to the work of the Government engineers. +The sub-station of the Survey at Urbana, Ill., was promptly notified of +the disaster on the afternoon of November 13th. Arrangements were +immediately made, whereby Mr. R. Y. Williams, Mining Engineer in +Charge, and his Assistant, Mr. J. M. Webb, with their apparatus, +were rushed by special train to the scene, arriving early the following +day (Sunday).</p> + +<p> +Chief Mining Engineer, George S. Rice, Chief of Rescue Division, +J. W. Paul, and Assistant Engineer, F. F. Morris, learned of +the disaster through the daily press, at their homes in Pittsburg, on +Sunday. They left immediately with four sets of rescue apparatus, +reaching Cherry on Monday morning. Meantime, Messrs. Williams and Webb, +equipped with oxygen helmets, had made two trips into the shaft, but +were driven out by the heat. Both shafts were shortly resealed with a +view to combating the fire, which had now made considerable headway.</p> + +<p> +The direction of the operations at Cherry, was, by right of +jurisdiction, in charge of the State Mine Inspectors of Illinois, at +whose solicitation the Government engineers were brought into conference +as to the proper means to follow in an effort to get into the mine. The +disaster was not due to an explosion of coal or gas, but was the result +of a fire ignited in hay, in the stable within the mine. The flame had +come through the top of the air-shaft, and had disabled the ventilating +fans. A rescue corps of twelve men, unprotected by artificial breathing +apparatus, had entered the mine, and all had been killed. When the +shafts were resealed on Monday evening, the 15th, a small hole was left +for the insertion of a water-pipe or hose. During the afternoon and +evening, a sprinkler was rigged up, and, by Tuesday morning, was in +successful operation, the temperature in the shaft at that time being +109° Fahr. After the temperature had been reduced to about 100°, the +Federal engineers volunteered to descend into the shaft and make an +exploration. The rescue party, consisting of Messrs. Rice, Paul, and +Williams, equipped with artificial breathing apparatus, made an +exploration near the bottom of the air-shaft and located the first body. +After they had returned to the surface, three of the Illinois State +Inspectors, who had previously received training by the Government +engineers in the use of the rescue apparatus, including Inspectors Moses +and Taylor, descended, made +<!--png216--> +<span class = "pagenum">214</span> +<a name = "page214"> </a> +tests of the air, and found that with the fan running slowly, it was +possible to work in the shaft. The rescue corps then took hose down the +main shaft, having first attached it to a fire engine belonging to the +Chicago Fire Department. Water was directed on the fire at the bottom of +the shaft, greatly diminishing its force, and it was soon subdued +sufficiently to permit the firemen to enter the mine without the +protection of breathing apparatus.</p> + +<p> +Unfortunately, these operations could be pursued only under the most +disadvantageous circumstances and surrounded by the greatest possible +precautions, due to the frequent heavy falls of roof—a result of +the heating by the mine fire—and the presence of large quantities +of black-damp. All movements of unprotected rescuers had to be preceded +by exploration by the trained rescue corps, who analyzed the gases, as +the fire still continued to burn, and watched closely for falls, +possible explosions, or a revival of the fire. While the heavy work of +shoring up, and removing bodies, was being carried on by the unprotected +rescue force, the helmet-men explored the more distant parts of the +mine, and on Saturday afternoon, November 20th, one week after the +disaster, a room was discovered in which a number of miners, with great +presence of mind, had walled themselves in in order to keep out the +smoke and heat. From this room 20 living men were taken, of whom 12 were +recovered in a helpless condition, by the helmet-men.</p> + +<p> +This is not the first time this Government mining corps has performed +valiant services. Directly and indirectly the members have saved from +fifteen to twenty lives in the short time they have been organized. At +the Marianna, Pa., disaster, the corps found one man still alive among +150 bodies, and he was brought to the surface. He recovered entirely +after a month in the hospital.</p> + +<p> +At the Leiter mine, at Zeigler, Ill., two employees, who had been +trained in the use of the oxygen helmets by members of the Government’s +corps, went down into the mine, following an explosion, and brought one +man to the surface, where they resuscitated him.</p> + +<p> +Equally good service, either in actual rescue operations, or in +explorations after mine disasters, or in fire-fighting, has been +rendered by this force at the Darr, Star Junction, Hazel, Clarinda, +Sewickley, Berwind-White No. 37, and Wehrum, Pa., mine disasters; at +Monongah and Lick Branch, W. Va.; at Deering, Sunnyside, and Shelburn, +Ind., Jobs, Ohio, and at Roslyn, Wash.</p> + +<p> +<!--png217--> +<span class = "pagenum">215</span> +<a name = "page215"> </a> +<i>Explosives Laboratory.</i>—The rooms grouped at the south end +of Building No. 21, at Pittsburg, are occupied as a laboratory for the +chemical examination and analysis of explosives, and are in charge of +Mr. W. O. Snelling.</p> + +<p> +Samples of all explosives used in the testing gallery, ballistic +pendulum, pressure gauge, and other testing apparatus, are here +subjected to chemical analysis in order to determine the component +materials and their exact percentages. Tests are also made to determine +the stability of the explosive, or its liability to decompose at various +temperatures, and other properties which are of importance in showing +the factors which will control the safety of the explosive during +transportation and storage.</p> + +<p> +In the investigation of all explosives, the first procedure is a +qualitative examination to determine what constituents are present. +Owing to the large number of organic and inorganic compounds which enter +into the composition of explosive mixtures, this examination must be +thorough. Several hundred chemical bodies have been used in explosives +at different times, and some of these materials can be separated from +others with which they are mixed only by the most careful and exact +methods of chemical analysis.</p> + +<p> +Following the qualitative examination, a method is selected for the +separation and weighing of each of the constituents previously found to +be present. These methods, of course, vary widely, according to the +particular materials to be separated, it being usually necessary to +devise a special method of analysis for each explosive, unless it is +found, by the qualitative analysis, to be similar to some ordinary +explosive, in which case the ordinary method of analysis of that +explosive can be carried out. Most safety powders require special +treatment, while most grades of dynamite and all ordinary forms of black +blasting powder are readily analyzed by the usual methods.</p> + +<p> +The examination of black blasting powder has been greatly facilitated +and, at the same time, made considerably more accurate, by means of a +densimeter devised at this laboratory. In this apparatus a Torricellian +vacuum is used as a means of displacing the air surrounding the grains +of powder, and through very simple manipulation the true density of +black powder is determined with a high degree of accuracy. In Building +No. 17 there is an apparatus for separating or grading the sizes of +black powder (Fig. 1, <a href = "#plate_X">Plate X</a>).</p> + +<p> +By means of two factors, the moisture coefficient and the hygroscopic +<!--png218--> +<span class = "pagenum">216</span> +<a name = "page216"> </a> +coefficient, which have been worked out at this laboratory, a number of +important observations can be made on black powder, in determining the +relative efficiency of the graphite coating to resist moisture, and also +as a means of judging the thoroughness with which the components of the +powder are mixed. The moisture coefficient relates to the amount of +moisture which is taken up by the grains of the powder in a definite +time under standard conditions of saturation; and the hygroscopic +coefficient relates to the affinity of the constituents of the powder +for moisture under the same standard conditions.</p> + +<p> +Besides the examination of explosives used at the testing station, those +for the Reclamation Service, the Isthmian Canal Commission, and other +divisions of the Government, are also inspected and analyzed at the +explosives laboratory. At the present time, the Isthmian Canal +Commission is probably the largest user of explosives in the world, and +samples used in its work are inspected, tested, and analyzed at this +laboratory, and at the branch laboratories at Gibbstown and Pompton +Lakes, N. J., and at Xenia, Ohio.</p> + +<p> +Aside from the usual analysis of explosives for the Isthmian Canal +Commission, special tests are made to determine the liability of the +explosive to exude nitro-glycerine, and to deteriorate in unfavorable +weather conditions. These tests are necessary, because of the warm and +moist climate of the Isthmus of Panama.</p> + +<p> +<i>Gas and Dust Gallery No. 1.</i>—Gallery No. 1 is cylindrical in +form, 100 ft. long, and has a minimum internal diameter of 6⅓ ft. It +consists of fifteen similar sections, each 6⅔ ft. long and built up in +in-and-out courses. The first three sections, those nearest the concrete +head, are of ½-in. boiler-plate steel, the remaining twelve sections are +of ⅜-in. boiler-plate steel, and have a tensile strength of, at least, +55,000 lb. per sq. in. Each section has one release pressure door, +centrally placed on top, equipped with a rubber bumper to prevent its +destruction when opened quickly. In use, this door may be either closed +and unfastened, closed and fastened by stud-bolts, or left open. Each +section is also equipped with one ¾-in. plate-glass window, 6 by 6 in., +centrally placed in the side of the gallery (<a href = +"#fig_1">Fig. 1</a>, and Figs. 1 and 2, <a href = +"#plate_VI">Plate VI</a>). The sections are held together by a +lap-joint. At each lap-joint there is, on the interior of the gallery, a +2½-in. circular, angle iron, on the face of which a paper diaphragm may +be placed and held in +<!--png220--> +<span class = "pagenum">218</span> +<a name = "page218"> </a> +position by semicircular washers, studs, and wedges. These paper +diaphragms are used to assist in confining a gas-and-air mixture.</p> + +<!--png219--> +<p class = "illustration"> +<span class = "pagenum">[217]</span> +<a name = "page217"> </a> +<a name = "fig_1"><span class = "smallcaps">Fig. 1.</span></a><br> +<a href = "images/fig1.png"> +<img src = "images/thumb1.png" width = "288" height = "176" +alt = "Figure 1 thumbnail"></a><br> +<span class = "caption"> +EXPLOSIVES TESTING GALLERY No. 1</span></p> + +<p> +Natural gas from the mains of the City of Pittsburg is used to represent +that found in the mines by actual analysis. A typical analysis of this +gas is as follows:</p> + +<h5 class = "smallcaps">Volumetric Analysis of Typical Natural Gas.</h5> + +<table class = "inline"> + +<tr> +<td>Hydrogen gases</td> +<td class = "middle">0</td> +</tr> +<tr> +<td>Carbon dioxide</td> +<td class = "decimal"> 0.1</td> +</tr> +<tr> +<td>Oxygen</td> +<td class = "middle">0</td> +</tr> +<tr> +<td>Heavy hydrocarbons</td> +<td class = "middle">0</td> +</tr> +<tr> +<td>Carbon monoxide</td> +<td class = "middle">0</td> +</tr> +<tr> +<td>Methane</td> +<td class = "decimal">81.8</td> +</tr> +<tr> +<td>Ethane</td> +<td class = "decimal">16.8</td> +</tr> +<tr> +<td>Nitrogen</td> +<td class = "decimal"> 1.3</td> +</tr> +</table> + +<p> +The volume of gas used is measured by an accurate test meter reading to +one-twentieth of a cubic foot. The required amount is admitted near the +bottom, to one or more of the 20-ft. divisions of the gallery, from a +2-in. pipe, 14 ft. long. The pipe has perforations arranged so that an +equal flow of gas is maintained from each unit length.</p> + +<p> +Each 20-ft. division of the gallery is further equipped with an exterior +circulating system, as shown by <a href = "#fig_1">Fig. 1</a>, thus +providing an efficient method of mixing the gas with the air. For the +first division this circulating system is stationary, a portion of the +piping being equipped with heating coils for maintaining a constant +temperature.</p> + +<p> +The other divisions have a common circulating system mounted on a truck +which may be used on any of these divisions. Valves are provided for +isolating the fan so that a possible explosion will not +injure it.</p> + +<p> +In the center section of each division is an indicator cock which is +used to provide means of recording pressures above and below +atmospheric, or of sampling the air-and-gas mixture. The first division +of the gallery is equipped with shelves laterally placed, for the +support of coal dust.</p> + +<p> +The cannon in which the explosive is fired is placed in the concrete +head, the axial line of the bore-hole being coincident with that of the +gallery. This cannon (<a href = "#fig_2">Fig. 2</a>) is similar to +that used in the ballistic pendulum. The charge is fired electrically +from the observation room. To minimize the risk of loading the cannon, +the charger carries in his +<!--png223--> +<span class = "pagenum">219</span> +<a name = "page219"> </a> +pocket the plug of a stage switch (the only plug of its kind on the +ground), so that it is impossible to complete the circuit until the +charger has left the gallery. That portion of the first division of the +gallery which is not embedded in concrete, has a 3-in. covering made up +of blocks of magnesia, asbestos fiber, asbestos, cement, a thin layer of +8-oz. duck, and strips of water-proof roofing paper, the whole being +covered with a thick coat of graphite paint. The object of this covering +is to assist in maintaining a constant temperature.</p> + +<p class = "illustration"> +<a name = "fig_2"><span class = "smallcaps">Fig. 2.</span></a><br> +<img src = "images/fig2.png" width = "589" height = "215" +alt = "cannon as described in text"></p> + +<p> +The entire gallery rests on a concrete foundation 10 ft. wide, which has +a maximum height of 4½ ft. and a minimum height of 2 ft.</p> + +<p> +The concrete head in which the cannon is placed completely closes that +end of the gallery. A narrow drain extends under the entire length of +the gallery, and a tapped hole at the bottom of each section provides an +efficient means of drainage.</p> + +<p> +The buildings near the gallery are protected by two barricades near the +open end, each 10 ft. high and 30 ft. long. A back-stop, consisting of a +swinging steel plate, 6 ft. high and 9 ft. long, 50 ft. from the end of +the gallery, prevents any of the stemming from doing damage.</p> + +<p> +Tests are witnessed from an observation room, a protected position about +60 ft. from the gallery. The walls of the room are 18 in. thick, and the +line of vision passes through a ½-in. plate glass, 6 in. wide and 37 ft. +long, and is further confined by two external guards, each 37 ft. long +and 3 ft. wide.</p> + +<p> +In this gallery a series of experiments has been undertaken to determine +the amount of moisture necessary with different coal dusts, in order to +reduce the likelihood of a coal-dust explosion from a blown-out shot of +one of the dangerous types of explosives.</p> + +<p> +<!--png224--> +<span class = "pagenum">220</span> +<a name = "page220"> </a> +Coal dust taken from the roads of one of the coal mines in the Pittsburg +district required at least 12% of water to prevent an ignition. It has +also been proven that the finer the dust the more water is required, and +when it was 100-mesh fine, 30% of water was required to prevent its +ignition by the flame of a blown-out shot in direct contact. The methods +now used in sprinkling have been proven entirely insufficient for +thoroughly moistening the dust, and hence are unreliable in preventing a +general dust explosion.</p> + +<p> +At this station successful experiments have been carried out by using +humidifiers to moisten the atmosphere after the temperature of the air +outside the gallery has been raised to mine temperature and drawn +through the humidifiers. It has been found that if a relative humidity +of 90%, at a temperature of 60° Fahr., is maintained for 48 hours, +simulating summer conditions in a mine, the absorption of moisture by +the dust and the blanketing effect of the humid air prevent the general +ignition of the dust.</p> + +<p> +These humidity tests have been run in Gas and Dust Gallery No. 1 with +special equipment consisting of a Koerting exhauster having a capacity +of 240,000 cu. ft. per hour, which draws the air out of the gallery +through the first doorway, or that next the concrete head in which the +cannon is embedded.</p> + +<p> +The other end of the gallery is closed by means of brattice cloth and +paper diaphragms, the entire gallery being made practically air-tight. +The air enters the fifteenth doorway through a box, passing over steam +radiators to increase its temperature, and then through the humidifier +heads.</p> + + +<h5 class = "smallcaps">Explosives Testing Apparatus.</h5> + +<p> +There is no exposed woodwork in Building No. 17, which is 40 by 60 ft., +two stories high, and substantially constructed of heavy stone masonry, +with a slate roof. The structure within is entirely fire-proof. Iron +columns and girders, and wooden girders heavily encased in cement, +support the floors which are either of cement slab construction or of +wooden flooring protected by expanded metal and cement mortar, both +above and beneath. At one end, on the ground floor, is the exposing and +recording apparatus for flame tests of explosives, also pressure gauges, +and a calorimeter, and, at the other end, is a gallery for testing +safety lamps.</p> + +<p> +<!--png225--> +<span class = "pagenum">221</span> +<a name = "page221"> </a> +The larger portion of the second floor is occupied by a gas-tight +training room for rescue work, and an audience chamber, from which +persons interested in such work may observe the methods of procedure. A +storage room for rescue apparatus and different models of safety lamps +is also on this floor.</p> + +<p> +The disruptive force of explosives is determined in three ways, namely, +by the ballistic pendulum, by the Bichel pressure gauge, and by Trauzl +lead blocks.</p> + +<p> +<i>Ballistic Pendulum.</i>—The disruptive force of explosives, as +tested by the ballistic pendulum, is measured by the amount of +oscillation. The standard unit of comparison is a charge of ½ lb. of 40% +nitro-glycerine dynamite. The apparatus consists essentially of a 12-in. +mortar (Fig. 3, <a href = "#plate_VI">Plate VI</a>), weighing +31,600 lb., and suspended as a pendulum from a beam having knife-edges. +A steel cannon is mounted on a truck set on a track laid in line with +the direction of the swing of the mortar. At the time of firing the +cannon may be placed 1/16-in. from the muzzle of the mortar. The beam, +from which the mortar is suspended, rests on concrete walls, 51 by 120 +in. at the base and 139 in. high. On top of each wall is a 1-in. +base-plate, 7 by 48 in., anchored to the wall by ⅝-in. bolts, 28 in. +long. The knife-edges rest on bearing-plates placed on these +base-plates. The bearing-plates are provided with small grooves for the +purpose of keeping the knife-edges in oil and protected from the +weather. The knife-edges are each 6 in. long, 2 11/16 in. deep from +point to back, 2 in. wide at the back, and taper 50° with the +horizontal, starting on a line 1½ in. from the back. The point is +rounded to conform to a radius of ¼ in. The back of each is 2 in. longer +than the edge, making a total length of 10 in., and is 1 in. deep and 12 +in. wide. This shoulder gives bolting surface to the beam from which the +mortar is hung. The beam is of solid steel, has a 4 by 8-in. section, +and is 87 in. long. Heavy steel castings are bolted to it to take the +threads of the machine-steel rods which form the saddles on which the +mortar is suspended. The radius of the swing, measured from the point of +the knife-edges to the center of the trunnions, is 89¾ in.</p> + +<!--png197--> +<p class = "illustration"> +<span class = "pagenum">[opp. 196]</span> +<a name = "plate_VI"><span class = "smallcaps">Plate VI.</span></a><br> +<img src = "images/plate6a.jpg" width = "500" height = "268" +alt = "Plate VI Fig. 1"><br> +<span class = "smallcaps">Fig. 1.—Explosion from Coal Dust in Gas +and Dust Gallery No. 1.</span><br> +<img src = "images/plate6b.jpg" width = "500" height = "212" +alt = "Plate VI Fig. 2"><br> +<span class = "smallcaps">Fig. 2.—Mine Gallery No. 1.</span><br> +<img src = "images/plate6c.jpg" width = "500" height = "339" +alt = "Plate VI Fig. 3"><br> +<span class = "smallcaps">Fig. 3.—Ballistic Pendulum.</span></p> + +<p> +The cannon consists of two parts, a jacket and a liner. The jacket is 36 +in. long, has an external diameter of 24 in., and internal diameters of +9½ and 7½ in. It is made of the best cast steel or of forged steel.</p> + +<p> +The liner is 36½ in. long, with a 1-in. shoulder, 7¾ in. from the +<!--png226--> +<span class = "pagenum">222</span> +<a name = "page222"> </a> +back, changing the diameter from 9½ to 7½ in. The bore is smooth, being +2¼ in. in diameter and 21½ in. long. The cannon rests on a 4-wheel +truck, to which it is well braced by straps and rods. A track of 30-in. +gauge extends about 9 ft. from the muzzle of the mortar to the bumper +for the cannon.</p> + +<p> +The shot is fired by an electric firing battery, from the first floor of +Building No. 17, about 10 yd. away. To insure the safety of the operator +and the charger, the man who loads the cannon carries a safety plug +without which the charge cannot be exploded. The wires for connecting to +the fuse after charging are placed conveniently, and the safety plug is +then inserted in a box at the end of the west wall. The completion of +the firing battery by the switch at the firing place is indicated by the +flashing of a red light, after which all that is necessary to set off +the charge is to press a button on the battery. An automatic recording +device at the back of the mortar records the length of swing which, by a +vernier, may be read to 1/200 in.</p> + +<p> +<i>Bichel Pressure Gauges.</i>—Pressure gauges are constructed for +the purpose of determining the unit disruptive force of explosives +detonating at different rates of velocity, by measuring pressures +developed in an enclosed space from which the generated gases cannot +escape. The apparatus consists of a stout steel cylinder, which may be +made absolutely air-tight; an air-pump and proper connections for +exhausting the air in the cylinder to a pressure equivalent to 10 mm. of +mercury; an insulated plug for providing the means of igniting the +charge; a valve by which the gaseous products of combustion may be +removed for subsequent analysis; and an indicator drum (Fig. 1, +<a href = "#plate_VII">Plate VII</a>) with proper connections for +driving it at a determinable speed.</p> + +<!--png221--> +<p class = "illustration"> +<span class = "pagenum">[opp. 220]</span> +<a name = "plate_VII"><span class = "smallcaps">Plate +VII.</span></a><br> +<img src = "images/plate7a.jpg" width = "500" height = "390" +alt = "Plate VII Fig. 1"><br> +<span class = "smallcaps">Fig. 1.—Bichel Pressure +Gauges.</span><br> +<img src = "images/plate7b.jpg" width = "500" height = "418" +alt = "Plate VII Fig. 2"><br> +<span class = "smallcaps">Fig. 2.—Rate of Detonation +Recorder.</span></p> + +<p> +This apparatus is in the southeast corner of Building No. 17. The +cylinder is 31½ in. long, 19¾ in. in diameter, and is anchored to a +solid concrete footing at a convenient height for handling. The +explosion chamber is 19 in. long and 7⅞ in. in diameter, with a capacity +of exactly 15 liters. The cover of the cylinder is a heavy piece of +steel held in place by stout screw-bolts and a heavy steel clamp.</p> + +<p> +The charge is placed on a small wire tripod, and connections are made +with a fuse to an electric firing battery for igniting the charges. The +cover is drawn tight, with the twelve heavy bolts against lead washers. +The air in the cylinder is exhausted to 10 mm., mercury column, in order +to approach more closely the conditions of a stemmed +<!--png229--> +<span class = "pagenum">223</span> +<a name = "page223"> </a> +charge exploding in a bore-hole inaccessible to air; the indicator drum +is placed in position and set in motion; and, finally, the shot is +fired. The record shown on the indicator card is a rapidly ascending +curve for quick explosives and a shallower, slowly rising curve for +explosives of slow detonation. When the gases cool, the curve merges +into a straight line, which indicates the pressures of the cooled gases +on the sides of the chamber.</p> + +<p> +Since the ratio of the volume of the cylinder to the volume of the +charge may be computed, the pressure of the confined charge may also be +found, and this pressure often exceeds 100,000 lb. per sq. in. The +cooling effect of the inner surface on the gaseous products of +combustion, a vital point in computations of the disruptive force of +explosives by this method, is determined by comparing the pressures +obtained in the original cylinder with those in a second cylinder of +larger capacity, into which has been inserted one or more steel +cylinders to increase the superficial area while keeping the volume +equal to that of the first cylinders. By comparing results, a curve may +be plotted, which will determine the actual pressures developed, with +the surface-cooling effect eliminated.</p> + +<p> +<i>Trauzl Lead Blocks.</i>—The lead-block test is the method +adopted by the Fifth International Congress of Applied Chemistry as the +standard for measuring the disruptive force of explosives. The unit by +this test is defined to be the force required to enlarge the bore-hole +in the block to an amount equivalent to that produced by 10 grammes of +standard 40% nitro-glycerine dynamite stemmed with 50 grammes of dry +sand under standard conditions as produced with the tamping device. The +results of this test, when compared with those of the Bichel gauge, +indicate that, for explosives of high detonation, the lead block is +quite accurate, but for slow explosives, such as gunpowder, the +expansion of the gases is not fast enough to make comparative results of +value. The reason for this is that the gases escape through the bore of +the block rather than take effect in expanding the bore-hole.</p> + +<p> +The lead blocks are cylindrical, 200 mm. in diameter, and 200 mm. high. +Each has a central cavity, 25 mm. in diameter and 125 mm. deep +(Fig. 1, <a href = "#plate_IX">Plate IX</a>), in which the +charge is placed. The blocks are made of desilverized lead of the best +quality, and, as nearly as possible, under identical conditions. The +charge is placed in the cavity and prepared for detonation with an +electrical exploder and +<!--png230--> +<span class = "pagenum">224</span> +<a name = "page224"> </a> +stemming. After the explosion the bore-hole is pear-shaped, the size of +the cavity depending, not only on the disruptive power of the explosive, +but also on its rate of detonation, as already indicated. The size of +the bore-hole is measured by filling the cavity with water from a +burette. The difference in the capacity of the cavity before and after +detonation indicates the enlarging power of the explosive.</p> + +<p> +<i>Calorimeter.</i>—The explosion calorimeter is designed to +measure the amount of heat given off by the detonation of explosive +charges of 100 grammes. The apparatus consists of the calorimeter bomb +(Fig. 1, <a href = "#plate_VIII">Plate VIII</a>), the inner +receiver or immersion vessel, a wooden tub, a registering thermometer, +and a rocking frame. This piece of apparatus stands on the east side of +Building No. 17.</p> + +<p> +The bottle-shaped bomb is made of ½-in. wrought steel, and has a +capacity of 30 liters. On opposite sides near the top are bored +apertures, one for the exhaust valve for obtaining a partial vacuum +(about 20 mm., mercury column) after the bomb has been charged, the +other for inserting the plug through which passes the fuse wire for +igniting the charge. The bomb is closed with a cap, by which the chamber +may be made absolutely air-tight. It is 30 in. high with the cap on, +weighs 158 lb., and is handled to and from the immersion vessel by a +small crane.</p> + +<p> +The inner receiver is made of 1/16-in. sheet copper, 30⅞ in. deep, and +with an inner diameter of 17⅞ in. It is nickel-plated, and strengthened +on the outside with bands of copper wire, and its capacity is about 70 +liters. The outer tub is made of 1-in. lumber strengthened with four +brass hoops on the outside. It is 33 in. deep, and its inner diameter is +21 in.</p> + +<p> +The stirring device, operated vertically by an electric motor, consists +of a small wooden beam connected to a system of three rings having a +horizontal bearing surface. When the apparatus is put together, the +inner receiver rests on a small standard on top of the base of the outer +tank, and the rings of the stirring device are run between the bomb and +the inner receiver. The bomb itself rests on a small standard placed on +the bottom of the inner receiver. The apparatus is provided with a +snugly fitting board cover. The bomb is charged from the top, the +explosive being suspended in its center. The air is exhausted to the +desired degree of rarification. The caps are then screwed on, and the +apparatus is set together as described.</p> + +<p> +<!--png233--> +<span class = "pagenum">225</span> +<a name = "page225"> </a> +The apparatus is assembled on scales and weighed before the water is +poured in and after the receiver is filled. From the weight of the water +thus obtained and the rise of temperature, the calorific value may be +computed. The charge is exploded by electricity, while the water is +being stirred. The rise in the temperature of the water is read by a +magnifying glass, from a thermometer which measures temperature +differences of 0.01 degree. From the readings obtained, the maximum +temperature of explosion may be determined, according to certain +formulas for calorimetric experiments. Proper corrections are made for +the effects, on the temperature readings, of the formation of the +products of combustion, and for the heat-absorbing power of the +apparatus.</p> + +<p> +<i>Impact Machine.</i>—In Building No. 17, at the south side, is +an impact machine designed to gauge the sensitiveness of explosives to +shock. For this purpose, a drop-hammer, constructed to meet the +following requirements, is used: A substantial, unyielding foundation; +minimum friction in the guide-grooves; and no escape or scattering of +the explosive when struck by the falling weight. This machine is modeled +after one used in Germany, but is much improved in details of +construction.</p> + +<p> +The apparatus, Fig. 1, <a href = "#plate_XI">Plate XI</a>, +consists essentially of the following parts: An endless chain working in +a vertical path and provided with lugs; a steel anvil on which the charge +of explosive is held by a steel stamp; a demagnetizing collar moving +freely in vertical guides and provided with jaws placed so that the lugs +of the chain may engage them; a steel weight sliding loosely in vertical +guides and drawn by the demagnetizing collar to determinable heights +when the machine is in operation; a second demagnetizing collar, which +may be set at known heights, and provided with a release for the jaws of +the first collar; and a recording device geared to a vertically-driven +threaded rod which raises or lowers, sets the second demagnetizing +collar, and thus determines the height of fall of the weight. By this +apparatus the weight may be lifted to different known heights, and +dropped on the steel stamp which transmits the shock to the explosive. +The fall necessary to explode the sample is thus determined.</p> + +<p> +The hammers are of varying weight, the one generally used weighing 2,000 +grammes. As the sensitiveness of an explosive is influenced by +temperature changes, water at 25° cent. is allowed to flow through the +anvil in order to keep its temperature uniform.</p> + +<p> +<!--png234--> +<span class = "pagenum">226</span> +<a name = "page226"> </a> +<i>Flame Test.</i>—An apparatus, Fig. 2, <a href = +"#plate_VIII">Plate VIII</a>, designed to measure the length and +duration of flames given off by explosives, is placed at the northeast +corner of Building No. 17. It consists essentially of a cannon, a +photographing device, and a drum geared for high speed, to which a +sensitized film may be attached.</p> + +<!--png227--> +<p class = "illustration"> +<span class = "pagenum">[opp. 222]</span> +<a name = "plate_VIII"><span class = "smallcaps">Plate +VIII.</span></a><br> +<img src = "images/plate8a.jpg" width = "500" height = "387" +alt = "Plate VIII Fig. 1"><br> +<span class = "smallcaps">Fig. 1.—Explosives +Calorimeter.</span><br> +<img src = "images/plate8b.jpg" width = "500" height = "334" +alt = "Plate VIII Fig. 2"><br> +<span class = "smallcaps">Fig. 2.—Building No. 17, and Flame-Test +Apparatus.</span><br> +<img src = "images/plate8c.jpg" width = "500" height = "92" +alt = "Plate VIII Fig. 3"><br> +<span class = "smallcaps">Fig. 3.—Small Lead Block +Test.</span></p> + +<p> +About 13 ft. outside the wall of Building No. 17, set in a concrete +footing, is a cannon pointing vertically into an encasing cylinder or +stack, 20 ft. high and 43 in. in diameter. This cannon is a duplicate of +the one used for the ballistic pendulum, details of which have already +been given. The stack or cylinder is of ¼-in. boiler plate, in +twenty-four sections, and is absolutely tight against light at the base +and on the sides. It is connected with a dark room in Building No. 17 by +a light-tight conduit of rectangular section, 12 in. wide, horizontal on +the bottom, and sloping on the top from a height of 8¼ ft. at the stack +to 21 in. at the inside of the wall of the building.</p> + +<p> +The conduit is carefully insulated from the light at all joints, and is +riveted to the stack. A vertical slit, 2 in. wide and 8 ft. long, +coincident with the center line of the conduit, is cut in the stack. A +vertical plane drawn through the center line of the bore-hole of the +cannon and that of the slit, if produced, intersects the center line of +a quartz lens, and coincides with the center of a stenopaic slit and the +axis of the revolving drum carrying the film. The photographing +apparatus consists of a shutter, a quartz lens, and a stenopaic slit, 76 +by 1.7 mm., between the lens and the sensitized film on the rotary drum. +The quartz lens is used because it will focus the ultra-violet rays, +which are those attending extreme heat.</p> + +<p> +The drum is 50 cm. in circumference and 10 cm. deep. It is driven by a +220-volt motor connected to a tachometer which reads both meters per +second and revolutions per minute. A maximum peripheral speed of 20 m. +per sec. may be obtained.</p> + +<p> +When the cannon is charged, the operator retires to the dark room in +which the recording apparatus is located, starts the drum, obtains the +desired speed, and fires the shot by means of a battery. When developed, +the film shows a blur of certain dimensions, produced by the flame from +the charge. From the two dimensions—height and lateral +displacement—the length and duration of the flame of the explosive +are determined.</p> + +<p> +The results of flame tests of a permissible explosive and a test of +black blasting powder, all shot without stemming, are shown on +<!--png235--> +<span class = "pagenum">227</span> +<a name = "page227"> </a> +Fig. 2, <a href = "#plate_IX">Plate IX</a>. In this test, the +speed of the drum carrying the black powder negative was reduced to one +sixty-fourth of that for the permissible explosives, in order that the +photograph might come within the limits of the negative. In other words, +the duration of the black powder flame, as shown, should be multiplied +by 64 for comparison with that of the permissible explosive, which is +from 3,500 to 4,000 times quicker.</p> + +<!--png231--> +<p class = "illustration"> +<span class = "pagenum">[opp. 224]</span> +<a name = "plate_IX"><span class = "smallcaps">Plate IX.</span></a><br> +<img src = "images/plate9a.jpg" width = "500" height = "239" +alt = "Plate IX Fig. 1"><br> +<span class = "smallcaps">Fig. 1.—Trauzl Lead Blocks.</span><br> +<img src = "images/plate9b.jpg" width = "500" height = "573" +alt = "Plate IX Fig. 2"><br> +<span class = "smallcaps">Fig. 2.—Powder Flames.</span></p> + +<p> +<i>Apparatus for Measuring Rate of Detonation.</i>—The rate at +which detonation travels through a given length of an explosive can be +measured by an apparatus installed in and near Building No. 17. Its most +essential feature is a recording device, with an electrical connection, +by which very small time intervals can be measured with great +exactness.</p> + +<p> +The explosive is placed in a sheet-iron tube about 1½ in. in diameter +and 4 ft. long, and suspended by cords in a pit, 11 ft. deep and 16 ft. +in diameter. This pit was once used as the well of a gas tank, Fig. 2, +<a href = "#plate_VIII">Plate VIII</a>. In adapting the pit to its +new use, the tank was cut in two; the top half, inverted, was placed in +the pit on a bed of saw-dust, and the space between the tank and the +masonry walls of the pit was filled with saw-dust. The cover of the pit +consists of heavy timbers framed together and overlaid by a 12-in. layer +of concrete reinforced by six <span class = "heavy">I</span>-beams. Four +straps extend over the top and down to eight “deadmen” planted about 8 +ft. below the surface of the ground.</p> + +<p> +The recording device, known as the Mettegang recorder, Fig. 2, +<a href = "#plate_VII">Plate VII</a>, comprises two sparking induction coils +and a rapidly revolving metallic drum driven by a small motor, the +periphery of the drum having a thin coating of lampblack. A vibration +tachometer which will indicate any speed between 50 and 150 rev. per +sec., is directly connected to the drum, so that any chance of error by +slipping is eliminated. The wires leading to the primary coils of the +sparking coils pass through the explosive a meter or more apart. Wires +lead from the secondary coils to two platinum points placed a fraction +of a millimeter from the periphery of the drum. A separate circuit is +provided for the firing lines.</p> + +<p> +In making a test, the separate cartridges, with the paper trimmed from +the ends, are placed, end to end, in the sheet-iron tube; the drum is +given the desired peripheral speed, and the charge is exploded. The +usual length between the points in the tube is 1 m., and the time +required for the detonation of a charge of that length is shown by the +<!--png236--> +<span class = "pagenum">228</span> +<a name = "page228"> </a> +distance between the beginning of two rows of dots on the drum made by +the sparks from the secondary coil circuits, the dots starting the +instant the primary circuits are broken by the detonation. At one end of +the drum are gear teeth, 1 mm. apart on centers, which can be made to +engage a worm revolving a pointer in front of a dial graduated to +hundredths; by means of this and a filar eyepiece, the distance between +the start of the two rows of spark dots on the drum can be measured +accurately to 0.01 mm. As the drum is 500 mm. in circumference, and its +normal speed is 86 rev. per sec., it is theoretically possible to +measure time to one four-millionth of a second, though with a cartridge +1 m. long, such refinement has not been found necessary.</p> + +<p> +The use of small lead blocks affords another means of determining the +rate of detonation or quickness of an explosive. Each block (a cylinder, +2½ in. long and 1½ in. in diameter) is enclosed in a piece of paper so +that a shell is formed above the block, in which to place the charge. A +small steel disk of the same diameter as the block is first placed in +the shell on top of the block, then the charge with a detonator is +inserted. The charge is customarily 100 grammes. On detonation of the +charge, a deformation of the lead takes place, the amount of which is +due to the quickness of the explosive used (Fig. 3, <a href = +"#plate_VIII">Plate VIII</a>).</p> + +<h5>Sample Record of Tests.</h5> + +<p> +The procedure followed in the examination of an explosive is shown by +the following outline:</p> + +<p> +1.—<i>Physical Examination.</i></p> + +<p class = "hanging"> +(<i>a</i>).—Record of appearance and marks on original +package.</p> + +<p class = "hanging"> +(<i>b</i>).—Dimensions of cartridge.</p> + +<p class = "hanging"> +(<i>c</i>).—Weight of cartridge, color and specific gravity of +powder.</p> + +<p> +2.—<i>Chemical Analysis.</i></p> + +<p class = "hanging"> +(<i>a</i>).—Record of moisture, nitro-glycerine, sodium or +potassium nitrate, and other chemical constituents, as set forth by the +analysis; percentage of ash, hygroscopic coefficient—the amount of +water taken up in 24 hours in a saturated atmosphere, at 15° cent., by 5 +grammes, as compared with the weight of the explosive.</p> + +<p class = "hanging"> +(<i>b</i>).—Analysis of products of combustion from 100 grammes, +including gaseous products, solids, and water.</p> + +<p class = "hanging"> +<!--png237--> +<span class = "pagenum">229</span> +<a name = "page229"> </a> +(<i>c</i>).—Composition of gaseous products of combustion, +including carbon monoxide and carbon dioxide, hydrogen, nitrogen, +etc.</p> + +<p class = "hanging"> +(<i>d</i>).—Composition of solid products of combustion, +subdivided into soluble and insoluble.</p> + +<p> +<i>3.—A Typical Analysis of Natural Gas.</i></p> + +<p> +Used in tests, as follows:</p> + +<table class = "inline"> +<tr> +<td>Carbon dioxide</td> +<td class = "number">0.0</td> +<td class = "middle">per cent.</td> +</tr> +<tr> +<td>Heavy hydrocarbons</td> +<td class = "number">0.2</td> +<td class = "middle">” ”</td> +</tr> +<tr> +<td>Oxygen</td> +<td class = "number">0.1</td> +<td class = "middle">” ”</td> +</tr> +<tr> +<td>Carbon monoxide</td> +<td class = "number">0.0</td> +<td class = "middle">” ”</td> +</tr> +<tr> +<td>Methane</td> +<td class = "number">82.4</td> +<td class = "middle">” ”</td> +</tr> +<tr> +<td>Ethane</td> +<td class = "number">15.3</td> +<td class = "middle">” ”</td> +</tr> +<tr> +<td>Nitrogen</td> +<td class = "number underline">2.0</td> +<td class = "middle">” ”</td> +</tr> +<tr> +<td></td><td class = "number">100.00</td> +<td class = "middle">per cent.</td> +</tr> +</table> + +<p> +<i>4.—Typical Analysis of Bituminous Coal Dust, 100-Mesh Fine, +Used in Tests.</i></p> + +<table class = "inline"> +<tr> +<td>Moisture</td> +<td class = "number">1.90</td> +</tr> +<tr> +<td>Volatile matter</td> +<td class = "number">35.05</td> +</tr> +<tr> +<td>Fixed carbon</td> +<td class = "number">58.92</td> +</tr> +<tr> +<td>Ash</td> +<td class = "number underline">4.13</td> +</tr> +<tr> +<td></td> +<td class = "number">100.00</td> +</tr> +<tr> +<td>Sulphur</td> +<td class = "number">1.04</td> +</tr> +</table> + +<p> +<i>5.—An Average Analysis of Detonators.</i></p> + +<p> +Used on Trauzl lead blocks, pressure gauge, calorimeter, and small lead +blocks:</p> + +<table class = "inline"> +<tr> +<td class = "midway" rowspan = "2"><i>M</i> - <i>l</i></td> +<td class = "midway underline"><i>l</i></td> +<td class = "midway" rowspan = "2">. Triple-strength exploder.</td> +</tr> +<tr> +<td class = "midway"><i>m</i></td> +</tr> +</table> + +<table class = "inline"> +<tr> +<td width = "33%">Charge</td> +<td>1.5729 grammes.</td> +<td></td><td></td> +</tr> +<tr> +<td></td><td></td> +<td class = "small">Mercury<br> +fulminate.</td> +<td class = "small">Chlorate<br> +of potash.</td> +</tr> +<tr> +<td colspan = "2">Specification</td> +<td class = "middle">89.73</td> +<td class = "middle">10.27</td> +</tr> +</table> + +<p> +Used on all other tests:</p> + +<table class = "inline"> +<tr> +<td class = "midway" rowspan = "2"><i>M</i> - 260</td> +<td class = "midway underline"><i>l</i></td> +<td class = "midway" rowspan = "2">. Double-strength exploder.</td> +</tr> +<tr> +<td class = "midway"><i>m</i></td> +</tr> +</table> + +<table class = "inline"> +<tr> +<td width = "33%">Charge</td> +<td>0.9805 grammes.</td> +<td></td><td></td> +</tr> +<tr> +<td></td><td></td> +<td class = "small">Mercury<br> +fulminate.</td> +<td class = "small">Chlorate<br> +of potash.</td> +</tr> +<tr> +<td colspan = "2">Specification</td> +<td class = "middle">91.31</td> +<td class = "middle">8.69</td> +</tr> +</table> + +<p> +<!--png238--> +<span class = "pagenum">230</span> +<a name = "page230"> </a> +<i>6.—Ballistic-Pendulum Tests.</i></p> + +<p> +This record includes powder used, weight of charge, swing of mortar, and +unit disruptive charge, the latter being the charge required to produce +a swing of the mortar equal to that produced by ½ lb. (227 grammes) of +40% dynamite, or 3.01 in.</p> + +<p> +<i>7.—Record of Tests.</i></p> + +<p> +Tests Nos. 1 to 5 in Gallery No. 1, as set forth in preceding +circular.</p> + +<p> +<i>8.—Trauzl Lead-Block Test.</i></p> + +<p> +Powder and test numbers, expansion of bore-hole in cubic centimeters, +and average expansion compared with that produced by a like quantity (10 +grammes) of 40% dynamite, the latter giving an average expansion of 294 +cu. cm.</p> + +<p> +<i>9.—Pressure Gauge.</i></p> + +<p> +Powder and test number, weight of charge, charging density, height of +curve, pressure developed, and pressure developed after cooling, +compared with pressure developed after elimination of surface influences +by a like quantity (100 grammes) of 40% dynamite, the average being +8,439 kg. per sq. cm.</p> + +<p> +<i>10.—Rate of Detonation.</i></p> + +<p> +Powder and test number, size of cartridge, and rate of detonation in +meters per second, for comparison with rate of detonation of 40% +dynamite, which, under the same conditions, averages 4,690 m. +per sec.</p> + +<p> +<i>11.—Impact Machine.</i></p> + +<p> +Explosive and test numbers, distance of fall (2,000-gramme weight) +necessary to cause explosion, for comparison with length of fall, 11 +cm., necessary to cause explosion of 40% dynamite.</p> + +<p> +<i>12.—Distance of Explosive Wave Transmitted by 1.25 by 8-in. +Cartridge.</i></p> + +<p> +Explosive and test numbers, weight of cartridge, distance separating +cartridges in tests, resulting explosion or non-explosion, for +comparison with two cartridges of 40% dynamite, hung, under identical +conditions, 13 in. apart, end to end, in which case detonation of the +first cartridge will explode the second.</p> + +<p> +<i>13.—Flame Test.</i></p> + +<p> +Explosive and test numbers, charge 100 grammes with 1 lb. of clay +stemming, average length of flame and average duration of flame, for +comparison with photographs produced by 40% dynamite under like +conditions.</p> + +<p> +<!--png241--> +<span class = "pagenum">231</span> +<a name = "page231"> </a> +<i>14.—Small Lead Blocks.</i></p> + +<p> +Powder and test numbers, weight of charge, and compression produced in +blocks.</p> + +<p> +<i>15.—Calories Developed.</i></p> + +<p> +Number of large calories developed per kilogramme of explosive, for +comparison with 1,000 grammes of 40% dynamite, which develop, on an +average, 1,229 large calories.</p> + +<h5>Blasting Powder Separator.</h5> + +<p> +The grains of black blasting powder are graded by a separator, similar +to those used in powder mills, but of reduced size. It consists of an +inclined wooden box, with slots on the sides to carry a series of +screens, and a vertical conduit at the end for carrying off the grains +as they are screened into separate small bins (Fig. 1, <a href = +"#plate_X">Plate X</a>). At the upper end of the screens is a small +12 by 16-in. hopper, with a sliding brass apron to regulate the feed. +The screens are shaken laterally by an eccentric rod operated by hand. +The top of the hopper is about 6½ ft. above the floor. The box is 6 ft. +10 in. long, from tip to tip, and inclines at an angle of 9 degrees.</p> + +<!--png239--> +<p class = "illustration"> +<span class = "pagenum">[opp. 230]</span> +<a name = "plate_X"><span class = "smallcaps">Plate X.</span></a><br> +<img src = "images/plate10a.jpg" width = "500" height = "332" +alt = "Plate X Fig. 1"><br> +<span class = "smallcaps">Fig. 1.—Separator for Grading Black +Powder.</span><br> +<img src = "images/plate10b.jpg" width = "500" height = "232" +alt = "Plate X Fig. 2"><br> +<span class = "smallcaps">Fig. 2.—Safety Lamp Testing +Gallery.</span><br> +<img src = "images/plate10c.jpg" width = "500" height = "249" +alt = "Plate X Fig. 3"><br> +<span class = "smallcaps">Fig. 3.—Mine Gallery No. 2.</span></p> + +<p> +After separation the grains fall through a vertical conduit, and thence +to the bins through zinc chutes, 1 by 2 in. in section. Care is taken to +have no steel or iron exposed to the powder.</p> + +<p> +The screens are held by light wooden frames which slip into the inclined +box from the upper end. In this way, any or all of the screens may be +used at once, thus separating all grades, or making only such +separations as are desired. The screens with the largest meshes are +diagonally-perforated zinc plates. Table 2 gives the number of holes per +square foot in zinc plates perforated with circular holes of the +diameters stated.</p> + +<h5 class = "smallcaps">TABLE 2.—Number of Holes per Square Foot +in Zinc Plates with Circular Perforations.</h5> + +<table class = "lines"> +<tr class = "lines"> +<th>Diameter,<br> +in inches</th> +<th class = "leftline">Number<br> +of holes.</th> +</tr> +<tr> +<td class = "middle">1/2</td> +<td class = "number leftline">353</td> +</tr> +<tr> +<td class = "middle">4/10</td> +<td class = "number leftline">518</td> +</tr> +<tr> +<td class = "middle">1/3</td> +<td class = "number leftline">782</td> +</tr> +<tr> +<td class = "middle">1/4</td> +<td class = "number leftline">1,392</td> +</tr> +<tr> +<td class = "middle">1/6</td> +<td class = "number leftline">1,680</td> +</tr> +<tr> +<td class = "middle">1/8</td> +<td class = "number leftline">3,456</td> +</tr> +<tr> +<td class = "middle">1/10</td> +<td class = "number leftline">6,636</td> +</tr> +<tr> +<td class = "middle">1/16</td> +<td class = "number leftline">12,800</td> +</tr> +</table> + +<p> +The finer meshes are obtained by using linen screens with holes of two +sizes, namely, 1/20 in. square and 1/28 in. square.</p> + +<p> +<!--png242--> +<span class = "pagenum">232</span> +<a name = "page232"> </a> +Until a few years ago, black blasting powder was manufactured in the +sizes given in Table 3.</p> + +<h5 class = "smallcaps">TABLE 3.—Gradation of Black Blasting +Powder.</h5> + +<table class = "lines"> +<tr class = "lines"> +<th>Grade.</th> +<th class = "leftline">Mesh.</th> +</tr> +<tr> +<td>CC</td> +<td class = "hyphen leftline">2-2½</td> +</tr> +<tr> +<td>C</td> +<td class = "hyphen leftline">2½-3</td> +</tr> +<tr> +<td>F</td> +<td class = "hyphen leftline">3-5</td> +</tr> +<tr> +<td>FF</td> +<td class = "hyphen leftline">5-8</td> +</tr> +<tr> +<td>FFF</td> +<td class = "hyphen leftline">8-16</td> +</tr> +<tr> +<td>FFFF</td> +<td class = "hyphen leftline">16-28</td> +</tr> +</table> + +<p> +In late years there has been considerable demand for special sizes and +mixed grains for individual mines, especially in Illinois. As no +material change has been made in the brands, the letters now used are +not indicative of the size of the grains, which they are supposed to +represent. Of 29 samples of black blasting powder recently received from +the Illinois Powder Commission, only 10 were found to contain 95% of the +size of grains they were supposed to represent; 4 contained 90%; 7 +varied from 80 to 90%; several others were mixtures of small and large +grains, and were branded FF black blasting powder; and one sample +contained only 8.5% of the size of grains it was supposed to represent. +The remaining samples showed many variations, even when sold under the +same name. The practice of thus mixing grades is exceedingly dangerous, +because a miner, after becoming accustomed to one brand of FF powder of +uniform separation, may receive another make of similar brand but of +mixed grains, and, consequently, he cannot gauge the quantity of powder +to be used. The result is often an over-load or a blown-out shot. The +smaller grains will burn first, and the larger ones may be thrown out +before combustion is complete, and thus ignite any fire-damp +present.</p> + +<!--png243--> +<p class = "illustration"> +<span class = "pagenum">[opp. 232]</span> +<a name = "plate_XI"><span class = "smallcaps">Plate XI.</span></a><br> +<img src = "images/plate11a.jpg" width = "402" height = "500" +alt = "Plate XI Fig. 1"><br> +<span class = "smallcaps">Fig. 1.—Impact Machine.</span><br> +<img src = "images/plate11b.jpg" width = "368" height = "500" +alt = "Plate XI Fig. 2"><br> +<span class = "smallcaps">Fig. 2.—Lamp Testing Box.</span></p> + +<h5>Lamp Testing Gallery.</h5> + +<p> +At the Pittsburg testing station, there is a gallery for testing safety +lamps in the presence of various percentages of inflammable gas. In this +gallery the safety of the lamps in these gaseous mixtures may be tested, +and it is also possible for mine inspectors and fire bosses to bring +their safety lamps to this station, and test their measurements of +percentage of gas, by noting the length and the appearance of the flame +in the presence of mixtures containing known percentages of methane +and air.</p> + +<p> +<!--png245--> +<span class = "pagenum">233</span> +<a name = "page233"> </a> +The gas-tight gallery used for testing the lamps, consists of a +rectangular conduit (Fig. 2, <a href = "#plate_X">Plate X</a>), +having sheet-steel sides, 6 mm. thick and 433 mm. wide, the top and +bottom being of channel iron. The gallery rests on two steel trestles, +and to one end is attached a No. 5 Koerting exhauster, capable of +aspirating 50 cu. m. per min., under a pressure of 500 mm. of water, +with the necessary valve, steam separator, etc. The mouth of the +exhauster passes through the wall of the building and discharges into +the open air.</p> + +<p> +Besides the main horizontal conduit, there are two secondary conduits +connected by a short horizontal length, and the whole is put together so +that the safety lamp under test may be placed in a current of air, or of +air and gas, which strikes it horizontally, vertically upward or +downward, or at an angle of 45° (<a href = "#fig_3">Fig. 3</a>). +The path of the current is determined by detachable sheet-steel +doors.</p> + +<p class = "illustration"> +<a name = "fig_3"><span class = "smallcaps">Fig. 3.</span></a><br> +<img src = "images/fig3.png" width = "600" height = "246" +alt = "SAFTY [sic] LAMP TESTING GALLERY" +title = "SAFTY [sic] LAMP TESTING GALLERY"></p> + +<p> +There are five double observing windows of plate glass, which open on +hinges. The size of each window is 7½ by 3 in.; the inner glass is ¼ in. +thick and the outer one, ½ in. thick. These glasses are separated by a +space of ¼ in. The upper conduit has four safety doors along the top, +each of the inclined conduits has one safety door, and the walls and +windows are provided with rubber gaskets or asbestos packing, to make +them gas-tight. The cross-sectional area of the conduit is 434 +sq. cm.</p> + +<p> +The air inlet consists of 36 perforations, 22 mm. in diameter, in a +bronze plate or diaphragm. The object of this diaphragm is to produce +pressure in the conduit before the mixing boxes, and permit the +measuring of the velocity of the current. The air-current, after +<!--png246--> +<span class = "pagenum">234</span> +<a name = "page234"> </a> +passing through the holes, enters the mixer, a cast-steel box traversed +by 36 copper tubes, each perforated by 12 openings, 3 mm. in diameter, +arranged in a spiral along its length and equally spaced. The total +cross-sectional area of the tubes is 137 sq. cm.</p> + +<p> +The explosive gas enters the interior of the box around the tubes +through large pipes, each 90 mm. in diameter, passes thence through the +432 openings in the copper tubes, and mixes thoroughly with the air +flowing through these tubes. The current through the apparatus is +induced by the exhauster, and its course is determined by the position +of the doors.</p> + +<p> +The gallery can be controlled so as to provide rapidly and easily a +current of known velocity and known percentage of methane. In the +explosive current of gas and air, safety lamps of any size or design can +be tested under conditions simulating those found occasionally in mines, +air-currents containing methane in dangerous proportions striking the +lamps at different angles, and the relative safety of the various types +of lamps under such conditions can be determined. In this gallery it is +also possible to test lighting devices either in a quiet atmosphere or +in a moving current, and, by subjecting the lamps to air containing +known percentages of methane, it is possible to acquaint the user with +the appearance of the flame caps.</p> + +<h5>Breathing Apparatus.</h5> + +<p> +With this apparatus, the wearer may explore a gaseous mine, approach +fires for the purpose of fighting them, or make investigations after an +explosion. Its object is to provide air or oxygen to be breathed by the +wearer in coal mines, when the mine air is so full of poisonous gases as +to render life in its presence impossible.</p> + +<p> +A variety of forms of rescue helmets and apparatus are on the market, +almost all of European manufacture, which are being subjected to +comparative trials as to their durability and safety, the ease or +inconvenience involved in their use, etc. All consist essentially of +helmets which fit air-tight about the head, or of air-tight nose clamps +and mouthpieces (Fig. 1, <a href = "#plate_XII">Plate XII</a>).</p> + +<p> +These several forms of breathing apparatus are of three types:</p> + +<p> +1.—The liquid-air type, in which air, in a liquid state, +evaporates and provides a constant supply of fresh air.</p> + +<p> +2.—The chemical oxygen-producing type, which artificially makes or +supplies oxygen for breathing at about the rate required; and,</p> + +<p> +<!--png249--> +<span class = "pagenum">235</span> +<a name = "page235"> </a> +3.—The compressed-oxygen type.</p> + +<p> +Apparatus of the first type, weighing 20 lb., supplies enough air to +last about 3 hours, and the products of breathing pass through a +check-valve directly into space. Apparatus of the second type supplies +oxygen obtained from oxygen-producing chemicals, and also provides means +of absorbing the carbonic acid gas produced in respiration. They contain +also the requisite tubes, valves, connections, etc., for the +transmission of the fresh air and the respired air so as to produce +sufficient oxygen while in use; to absorb and purify the products of +expiration; and to convey the fresh air to the mouth without +contamination by the atmosphere in which the apparatus is used. Three +oxygen-generating cartridges are provided, each supplying oxygen enough +for 1 hour, making the total capacity 3 hours. Changes of cylinders can +be made in a few seconds while breathing is suspended. This apparatus +weighs from 20 to 25 lb., according to the number of oxygen generators +carried. The cartridges for generating oxygen, provided with this +apparatus, are of no value after having been used for about an hour.</p> + +<p> +The third type of apparatus is equipped with strong cylinders charged +with oxygen under high pressure; two potash regenerative cans for +absorbing the carbon dioxide gas exhaled; a facial helmet; the necessary +valves, tubes, etc., for the control of the oxygen; and a finimeter +which registers the contents of the cylinders in atmospheres and minutes +of duration. The two cartridges used for absorbing the carbonic acid gas +are of no value after having been in use for two hours.</p> + +<p> +If inhalation is through the mouth alone, a mouthpiece is attached to +the end of the breathing tube by which the air or oxygen is supplied, +the nose is closed by a clip, and the eyes are protected by goggles. To +inhale through both nose and mouth, the miner wears a helmet or headgear +which can be made to fit tightly around the face. The helmet has two +tubes attached, one for inspiration and the other for expiration. In the +oxygen-cylinder apparatus these tubes lead to and from rubber sacks used +for pure-air and bad-air reserves.</p> + +<h5>Mine-Rescue Training.</h5> + +<p> +It has been found in actual service that when a miner, equipped with +breathing apparatus for the first time, enters a mine in which an +explosion has occurred, he is soon overcome by excitement or +<!--png250--> +<span class = "pagenum">236</span> +<a name = "page236"> </a> +nervousness induced by the artificial conditions of breathing imposed by +the apparatus, the darkness and heat, and the consciousness that he is +surrounded with poisonous gases. It has also been found that a brief +period of training in the use of such apparatus, under conditions +simulating those encountered in a mine after a disaster, gives the miner +confidence and enables him to use the apparatus successfully under the +strain of the vigorous exertion incident to rescue work.</p> + +<p> +The rescue corps consists of five or six miners under the direction of a +mining engineer who is experienced in rescue operations and <ins class = +"correction" title = "text reads ‘familar’">familiar</ins> with the +conditions existing after mine disasters. The miners work in pairs, so +that one may assist the other in case of accident, or of injury to the +breathing apparatus, and so that each may watch the condition of the +oxygen supply, as shown by the gauges in the other’s outfit.</p> + +<p> +The training is given in the gas-tight room of Building No. 17, or in +similar rooms at sub-stations (Fig. 2, <a href = +"#plate_XII">Plate XII</a>). This room is made absolutely dark, and +is filled with formaldehyde gas, SO<sub>2</sub>, CO<sub>2</sub>, or CO, +produced by burning sulphur or charcoal on braziers. At each period of +training, the miners enter and walk a distance of about 1 mile, the +average distance usually traveled from the mine mouth to the working +face or point of explosion. They then remove a number of timbers; lift a +quantity of brick or hard lump-coal into wheel-barrows; climb through +artificial tunnels, up and down inclines, and over surfaces strewn with +coal or stone; operate a machine with a device attached to it, which +automatically records the foot-pounds of work done; and perform other +vigorous exercise, during a period of 2 hours. This routine is repeated +daily during 1 week, after which the rescue corps is considered +sufficiently trained for active service.</p> + +<!--png247--> +<p class = "illustration"> +<span class = "pagenum">[opp. 234]</span> +<a name = "plate_XII"><span class = "smallcaps">Plate +XII.</span></a><br> +<img src = "images/plate12a.jpg" width = "500" height = "381" +alt = "Plate XII Fig. 1"><br> +<span class = "smallcaps">Fig. 1.—Breathing and Rescue +Apparatus.</span><br> +<img src = "images/plate12b.jpg" width = "500" height = "351" +alt = "Plate XII Fig. 2"><br> +<span class = "smallcaps">Fig. 2.—Rescue Training Room.</span></p> + +<p> +The apparatus used for recording the foot-pounds of work done by the +person operating the work machine within the gas-tight rescue room, +comprises a small dial with electrical connections, which records the +number of strokes made by the machine, and a pencil point which rests on +a paper diaphragm, fastened to a horizontal brass disk. This disk is +driven by clockwork, and makes one complete revolution per hour. When +the machine is in operation, the pencil point works back and forth, +making a broad line on the paper; when the operator of the machine +rests, the pencil point traces a single line. The +<!--png251--> +<span class = "pagenum">237</span> +<a name = "page237"> </a> +apparatus thus records the number of strokes given by the operator +during a given time. From the weight lifted, the height of lift, and the +number of strokes in the given time, the foot-pounds of work are readily +calculated.</p> + +<h5>Electric Testing Apparatus.</h5> + +<p> +On the ground floor of Building No. 10, two rooms are occupied as +laboratories for investigating the electrical equipment used in mining +operations. The purpose of these investigations is to ascertain the +conditions under which electricity of various voltages may be used with +safety—in mine haulage, hoisting, pumping, or lighting—in +the presence of dangerous mixtures of explosive gases or of dust. It is +also proposed to test various kinds of insulation and insulators in this +laboratory, and to determine the durability of such insulation in the +presence of such corrosive gases and water as are found in mines.</p> + +<p> +A water-proof wooden tank, measuring 15 by 5 by 5 ft., is installed, in +which insulation and insulating materials are tested under either pure +or polluted water. Various electric lighting devices and equipment can +be connected from a switch-board in Building No. 17 with Gas-and-Dust +Gallery No. 2, for testing the effect of such lighting apparatus in the +presence of explosive mixtures of gas and dust, as set forth on <a href += "#page220">page 220</a>.</p> + +<p> +In the electrical laboratory, Building No. 10, is a booster set +developing 60 kw., and an appropriate switch-board for taking direct +current at 220 volts from the turbo-generator and converting it into +current varying from 0 to 750 volts. There are also transformers for +developing 60-cycle, alternating current at voltages of from 110 to +2,200. The switch-board is designed to handle these various voltages and +to communicate them to the apparatus under test in Building No. 10, +Gallery No. 2, or elsewhere.</p> + +<p> +Tests are in progress of insulating materials for use in mines, and of +electric fuses, lights, etc., in Gallery No. 2 (Fig. 3, <a href = +"#plate_X">Plate X</a>), and in the lamp-testing box (Fig. 2, <a +href = "#plate_XI">Plate XI</a>). It is proposed, at the earliest +possible date, to make comparative tests of the safety of various mine +locomotives and mine-hoisting equipment through the medium of this +laboratory, and it is believed that the results will furnish valuable +information as a guide to the safety, reliability, and durability of +these appliances when electrically operated.</p> + +<p> +<!--png252--> +<span class = "pagenum">238</span> +<a name = "page238"> </a> +<i>Electric Lamp and Fuse Testing Box.</i>—An apparatus for +testing safety lamps and electric lights and fuses, consists of ¼-in. +iron plates, bolted together with 1½ in. angle-irons to form a box with +inside dimensions of 18 by 18 by 24 in. The box is placed on a stand at +such a height that the observation windows are on a level with the +observer’s eye (Fig. 2, <a href = "#plate_XI">Plate XI</a>), and it +is connected, by a gas-pipe, with a supply of natural gas which can be +measured by a gas-holder or meter alongside the box.</p> + +<p> +By the use of this apparatus the effect of explosive gas on flames, of +electric sparks on explosive mixtures of gas and air, and of breaking +electric lamps in an explosive mixture of gas and air, may be studied. +The safety lamps are introduced into the box from beneath, through a +hole 6 in. square, covered with a hinged iron lid, admission to which is +had through a flexible rubber sleeve, 20 in. long.</p> + +<p> +The behavior of the standard safety lamp and of the safety lamps +undergoing test may be compared in this box as to height of flame for +different percentages of methane in the air, the effect of such flames +in igniting gas, etc.</p> + +<p> +In each end of the box is an opening 1 ft. square, over which may be +placed a paper diaphragm held by skeleton doors, the purpose of which is +to confine the gas in such a manner that, should an explosion occur, no +damage would be done. In the front of the box are two plate-glass +observing windows, 2⅝ by 5½ in. In the side of the box, between the two +windows, is a ⅜-in. hole, which can be closed by a tap-screw, through +which samples for chemical analysis are drawn.</p> + +<p> +The gasometer consists of two iron cans, the lower one being open at the +top and filled with water and the upper one open at the bottom and +suspended by a counterweight. The latter has attached to its upper +surface a scale which moves with it, thereby measuring the amount of gas +in the holder. A two-way cock permits the admission of gas into the +gasometer and thence into the testing box.</p> + +<p> +<i>Gas-and-Dust Gallery No. 2.</i>—This gallery is constructed of +sheet steel and is similar to Gallery No. 1, the length, however, being +only 30 ft. and the diameter 10 ft. It rests on a concrete foundation +(Fig. 3, <a href = "#plate_X">Plate X</a>). Diaphragms can be +placed across either extremity, or at various sections, to confine the +mixtures of gas and air in which the tests are made. The admission of +gas is controlled by pipes and valves, and the gas and air can be +stirred or mixed by a fan, as described for Gallery No. 1, and as shown +by <a href = "#fig_1">Fig. 1</a>.</p> + +<p> +<!--png253--> +<span class = "pagenum">239</span> +<a name = "page239"> </a> +Gallery No. 2 is used for investigating the effect of flames of various +lamps, of electric currents, motors, and coal-cutting machines, in the +presence of known mixtures of explosive gas and air. It is also used for +testing the length of flame of safety lamps in still air carrying +various proportions of methane, and, for this purpose, is more +convenient than the lamp gallery. In tests with explosive mixtures, +after the device to be tested has been introduced and preparations are +completed, operations are controlled from a safe distance by a +switch-board in a building near-by.</p> + +<p> +Among other investigations conducted in this gallery are those of the +effect of sparks on known gas mixtures. These sparks are such as those +struck from a pick on flint, but in this case they are produced by +rubbing a rapidly revolving emery wheel against a steel file. The effect +of a spark produced by a short circuit of known voltage, the flame from +an arc lamp, etc., may also be studied in this gallery.</p> + + +<h5 class = "smallcaps">Structural Materials Investigations.</h5> + +<p> +The structural materials investigations are being conducted for the +purpose of determining the nature and extent of the materials available +for use in the building and construction work of the Government, and how +these materials may be used most efficiently.</p> + +<p> +These investigations include:</p> + +<p> +(1).—Inquiries into the distribution and local availability, near +each of the building centers in the United States, of such materials as +are needed by the Government.</p> + +<p> +(2).—How these materials may be used most efficiently.</p> + +<p> +(3).—Their fire-resisting qualities and strength at different +temperatures.</p> + +<p> +(4).—The best and most economic methods of protecting steel by +fire-resistant covering.</p> + +<p> +(5).—The most efficient methods of proportioning and mixing the +aggregate, locally available, for different purposes.</p> + +<p> +(6).—The character and value of protective coatings, or of various +mixes, to prevent deterioration by sea water, alkali, and other +destructive agencies.</p> + +<p> +(7).—The kinds and forms of reinforcement for concrete necessary +to secure the greatest strength in beams, columns, floor slabs, etc.</p> + +<p> +(8).—Investigation of the clays and of the products of clays +needed in Government works, as to their strength, durability, +suitability as +<!--png254--> +<span class = "pagenum">240</span> +<a name = "page240"> </a> +fire-resisting materials, and the methods of analyzing and testing clay +products.</p> + +<p> +(9).—Tests of building stones, and investigations as to their +availability near the various building centers throughout the United +States.</p> + +<p> +The operations of the Structural Materials Division include +investigations into cement-making materials, constituent materials of +concrete, building stones, clays, clay products, iron, steel, and +miscellaneous materials of construction, for the use of the Government. +The organization comprises a number of sections, including those for the +chemical and physical examination of Departmental purchases; field +sampling and laboratory examination of constituent materials of concrete +collected by skilled field inspectors in the neighborhood of the larger +commercial and building centers; similar field sampling of building +stones and of clays and clay products, offered for use in Government +buildings or engineering construction; and the forwarding of such +samples to the testing laboratories at St. Louis or Pittsburg for +investigation and test. The investigative tests include experiments +regarding destructive agencies, such as electrolysis, alkaline earths +and waters, salt water, fire, and weathering; also experiments with +protective and water-proofing agencies, including the various washes or +patented mixtures on the market, and the methods of washing, and mixing +mortars and concrete, which are likely to result in rendering such +materials less pervious to water.</p> + +<p> +Investigations are also being conducted to determine the nature and +extent of materials available for use in the building-construction work +of the Government, and how these materials may be used most efficiently +and safely. While the act authorizing this work does not permit +investigations or tests for private parties, it is believed that these +tests for the Government cannot fail to be of great general value. The +aggregate expenditure by the Federal Government in building and +engineering construction is about $40,000,000 annually. This work is +being executed under so many different conditions, at points so widely +separated geographically, and requires so great a variety of materials, +that the problems to be solved for the Government can hardly fail to +cover a large share of the needs of the Engineering Profession, State +and municipal governments, and the general public.</p> + +<p> +<i>Character of the Work.</i>—The tests and analyses, of the +materials of construction purchased by the various bureaus and +departments for the use of the Government, are to determine the +character, quality, +<!--png255--> +<span class = "pagenum">241</span> +<a name = "page241"> </a> +suitability, and availability of the materials submitted, and to +ascertain data leading to more accurate working values as a basis for +better working specifications, so as to enable Government officials to +use such materials with more economy and increased efficiency.</p> + +<p> +Investigative tests of materials entering into Government construction, +relative to the larger problems involved in the use of materials +purchased by the Government, include exhaustive study of the suitability +for use, in concrete construction on the Isthmian Canal, of the sand and +stone, and of the cementing value of pozzuolanic material, found on the +Isthmus; the strength, elasticity, and chemical properties of structural +steel for canal lock-gates; of wire rope and cables for use in hoisting +and haulage; and the most suitable sand and stone available for concrete +and reinforced concrete for under-water construction, such as the +retaining walls being built by the Quartermaster’s Department of the +Army, in San Francisco Harbor.</p> + +<p> +These tests also include investigations into the disintegrating effect +of alkaline soil and water on the concrete and reinforced concrete +structures of the Reclamation Service, with a view to preventing such +disintegration; investigations into the proper proportions and +dimensions of concrete and reinforced concrete structural columns, +beams, and piers, and of walls of brick and of building stone, and of +the various types of metal used for reinforcement by the Supervising +Architect in the construction of public buildings; investigations into +the sand, gravel, and broken stone available for local use in concrete +construction, such as columns, piers, arches, floor slabs, etc., as a +guide to the more economical design of public structures, and to +determine the proper method of mixing the materials to render the +concrete most impervious to water and resistant to weather and other +destructive agencies.</p> + +<p> +Other lines of research may be stated briefly as follows:</p> + +<p> +The extent to which concrete made from cement and local materials can be +most safely and efficiently used for different purposes under different +conditions;</p> + +<p> +The best methods for mixing and utilizing the various constituent +materials locally available for use in Government construction;</p> + +<p> +The materials suitable for the manufacture of cement on the public +lands, or where the Government has planned extensive building or +engineering construction work, where no cement plants now exist;</p> + +<p> +The kinds and forms of reinforcement for concrete, and the best +<!--png256--> +<span class = "pagenum">242</span> +<a name = "page242"> </a> +methods of applying them in order to secure the greatest strength in +compression, tension, shear, etc., in reinforced concrete beams, +columns, floor slabs, etc.;</p> + +<p> +The influence of acids, oils, salts, and other foreign materials, +long-continued strain, or electric currents, on the permanence of the +steel in reinforced concrete;</p> + +<p> +The value of protective coatings as preventives of deterioration of +structural materials by destructive agencies; and</p> + +<p> +The establishment of working stresses for various structural materials +needed by the Government in its buildings.</p> + +<p> +Investigations are being made into the effects of fire and the rate of +conductivity of heat on concrete and reinforced concrete, brick, tile, +building stone, etc., as a guide to the use of the most suitable +materials for fire-proof building construction and the proper +dimensioning of fire-resistive coverings.</p> + +<p> +Investigations and tests are being made, with a view to the preparation +of working specifications for use in Government construction, of bricks, +tile, sand-lime brick, paving brick, sewer pipe, roofing slates, +flooring tiles, cable conduits, electric insulators, architectural terra +cotta, fire-brick, and all shapes of refractories and other clay +products, regarding which no satisfactory data for the preparation of +specifications of working values now exist.</p> + +<p> +Investigations of the clay deposits throughout the United States are in +progress, to determine proper methods of converting them into building +brick, tile, etc., at the most reasonable cost, and the suitability of +the resulting material for erection in structural forms and to meet +building requirements.</p> + +<p> +Investigations are being made in the field, of building stones locally +available, and physical and chemical tests of these building stones to +determine their bearing or crushing strength; the most suitable mortars +for use with them; their resistance to weathering; their fire-resistive +and fire-proof qualities, etc., regarding which practically no adequate +information is available as a guide to Government engineering and +building design.</p> + +<p> +<i>Results Accomplished.</i>—During one period of six months +alone, more than 2,500 samples, taken from Government purchases of +structural materials, were examined, of which more than 300 failed to +meet the specified requirements, representing many thousands of dollars +worth of inferior material rejected, which otherwise would have been +<!--png257--> +<span class = "pagenum">243</span> +<a name = "page243"> </a> +paid for by the Government. These tests were the means of detecting the +inferior quality of large quantities of materials delivered on +contracts, and the moral effect on bidders has proven as important a +factor in the maintenance of a high quality of purchases, as in the +saving of money.</p> + +<p> +The examination of sands, gravels, and crushed stones, as constituent +materials for concrete and reinforced concrete construction, has +developed data showing that certain materials, locally available near +large building centers and previously regarded as inferior in quality, +were, in fact, superior to other and more expensive materials which it +had been proposed to use.</p> + +<p> +These investigations have represented an actual saving in the cost of +construction on the work of the Isthmian Canal Commission, of the +Supervising Architect, and of certain States and cities which have +benefited by the information disseminated regarding these constituent +materials.</p> + +<p> +Investigations of clay products, only recently inaugurated, have already +resulted in the ascertainment of important facts relative to the colloid +matter of clay and its measurement, and the bearing thereof on the +plasticity and working values of various clays. The study of the +preliminary treatment of clays difficult to handle dry, has furnished +useful information regarding the drying of such clays, and concerning +the fire resistance of bricks made of soft, stiff, or dried clay of +various densities.</p> + +<p> +The field collection and investigation of building-stone samples have +developed some important facts which had not been considered previously, +relative to the effect of quarrying, in relation to the strike and dip +of the bedding planes of building stone, and the strength and durability +of the same material when erected in building construction. These +investigations have also developed certain fundamental facts relative to +the effects of blasting (as compared with channeling or cutting) on the +strength and durability of quarried building stone.</p> + +<p> +<i>Mineral Chemistry Laboratories.</i>—Investigations and analyses +of the materials of engineering and building construction are carried on +at Pittsburg in four of the larger rooms of Building No. 21. In this +laboratory, are conducted research investigations into the effect of +alkaline waters and soils on the constituent materials of concrete +available in arid regions, as related to the life and permanency of the +concrete and reinforced concrete construction of the Reclamation +Service. +<!--png258--> +<span class = "pagenum">244</span> +<a name = "page244"> </a> +These investigations include a study of individual salts found in +particular alkalis, and a study of the results of allowing solutions of +various alkalis to percolate through cylinders of cement mortar and +concrete. Other research analyses have to do with the investigation of +destructive and preservative agencies for concrete, reinforced concrete, +and similar materials, and with the chemistry of the effects of salt +water on concrete, etc. The routine chemical analyses of the constituent +materials of concrete and cement-making materials, are made in this +laboratory, as are also a large number of miscellaneous chemical +analyses and investigations of reinforcement metal, the composition of +building stones, and allied work.</p> + +<p> +A heat laboratory, in charge of Dr. J. K. Clement, occupies three +rooms on the ground floor of Building No. 21, and is concerned chiefly +with the measurement of temperatures in gas producers, in the furnaces +of steam boilers, kilns, etc. The work includes determinations of the +thermal conductivity of fire clays, concrete, and other building +materials, and of their fire-resisting properties; measurements of the +thermal expansion and specific heats of fire-bricks, porcelain, and +glazes; and investigations of the effect of temperature variations on +the various chemical processes which take place in the fuel bed of the +gas producer, boiler furnace, etc.</p> + +<p> +The heat laboratory is equipped for the calibration of the thermometers +and pyrometers, and electrical and other physical apparatus used by the +various sections of the Technologic Branch.</p> + +<p> +For convenience in analyzing materials received from the various +purchasing officers attached to the Government bureaus, this work is +housed in a laboratory on the fourth floor of the Geological Survey +Building in Washington.</p> + +<p> +Large quantities and many varieties of building materials for use in +public buildings under contract with the Supervising Architect’s office, +are submitted to the laboratory by contractors to determine whether or +not they meet the specified requirements. Further examinations are made +of samples submitted by superintendents of construction, representing +material actually furnished by contractors. It is frequently found that +the sample of material submitted by the contractor is of far better +quality than that sent by the superintendent to represent deliveries. +The needed constant check on deliveries is thus provided.</p> + +<p> +<!--png259--> +<span class = "pagenum">245</span> +<a name = "page245"> </a> +In addition to this work for the office of the Supervising Architect, +similar work on purchases and supplies is carried on for the Isthmian +Canal Commission, the Quartermaster-General’s Department of the Army, +the Life Saving Service, the Reclamation Service, and other branches of +the Government. About 300 samples are examined each month, requiring an +average of 12 determinations per sample, or about 3,600 determinations +per month.</p> + +<p> +The chemical laboratory for testing Government purchases of structural +materials is equipped with the necessary apparatus for making the +requisite physical and chemical tests. For the physical tests of cement, +there are a tensile test machine, briquette moulds, a pat tank for +boiling tests to determine soundness, water tanks for the storage of +briquettes, a moist oven, apparatus to determine specific gravity, +fineness of grinding, etc.</p> + +<p> +The chemical laboratory at Washington is equipped with the necessary +analytical balances, steam ovens, baths, blast lamps, stills, etc., +required in the routine chemical analysis of cement, plaster, clay, +bricks and terra cotta, mineral paints and pigments, roofing material, +tern plate and asphaltic compounds, water-proofing materials, iron and +steel alloys, etc.</p> + +<p> +At present, materials which require investigative tests as a basis for +the preparation of suitable specifications, tests not connected with the +immediate determination as to whether or not the purchases are in +accordance with the specifications, are referred to the chemical +laboratories attached to the Structural Materials Division, at +Pittsburg.</p> + +<p> +The inspection and tests of cement purchased in large quantities, such +as the larger purchases on behalf of public-building construction under +the Supervising Architect, or the great 4,500,000-bbl. contract of the +Isthmian Canal Commission, are made in the cement-testing laboratory of +the Survey, in the Lehigh Portland cement district, at +Northampton, Pa.</p> + +<p> +<i>Testing Machines.</i>—The various structural forms into which +concrete and reinforced concrete may be assembled for use in +public-building construction, are undergoing investigative tests as to +their compressive and tensile strength, resistance to shearing, modulus +of elasticity, coefficient of expansion, fire-resistive qualities, etc. +Similar tests are being conducted on building stone, clay products, and +the structural forms in which steel and iron are used for building +construction.</p> + +<p> +<!--png260--> +<span class = "pagenum">246</span> +<a name = "page246"> </a> +The compressive, tensile, and other large testing machines, for all +kinds of structural materials reaching the testing stations, are under +the general supervision of Richard L. Humphrey, M. Am. Soc. C. E. +The immediate direction of the physical tests on the larger testing +machines is in charge of Mr. H. H. Kaplan.</p> + +<p> +Most of this testing apparatus, prior to 1909, was housed in buildings +loaned by the City of St. Louis, in Forest Park, St. Louis, Mo., and the +arrangement of these buildings, details of equipment, organization, and +methods of conducting the tests, are fully set forth in Bulletin No. 329 +of the U. S. Geological Survey. In brief, this equipment included +motor-driven, universal, four-screw testing machines, as follows: One +600,000-lb., vertical automatic, four-screw machine; one 200,000-lb., +automatic, four-screw machine; and one 200,000-lb. and one 100,000-lb. +machine of the same type, but with three screws. There are a number of +smaller machines of 50,000, 40,000, 10,000, and 2,000 lb., +respectively.</p> + +<p> +These machines are equipped so that all are available for making tensile +and compressive tests (Fig. 1, <a href = +"#plate_XIII">Plate XIII</a>). The 600,000-lb. machine is capable +of testing columns up to 30-ft. lengths, and of making transverse tests +of beams up to 25-ft. span, and tension tests for specimens up to 24 ft. +in length. The smaller machines are capable of making tension and +compressive tests up to 4 ft. in length and transverse beam tests up to +12 ft. span. In addition, there are ample subsidiary apparatus, +including concrete mixers with capacities of ½ and 1 cu. yd., five +hollow concrete block machines, automatic sifting machines, briquette +moulds, storage tanks, etc.</p> + +<!--png261--> +<p class = "illustration"> +<span class = "pagenum">[opp. 246]</span> +<a name = "plate_XIII"><span class = "smallcaps">Plate +XIII.</span></a><br> +<img src = "images/plate13a.jpg" width = "500" height = "335" +alt = "Plate XIII Fig. 1"><br> +<span class = "smallcaps">Fig. 1.—Testing Beam in 200,000-Lb. +Machine.</span><br> +<img src = "images/plate13b.jpg" width = "500" height = "283" +alt = "Plate XIII Fig. 2"><br> +<span class = "smallcaps">Fig. 2.—Fire Test of Panel.</span></p> + +<p> +At the Atlantic City sub-station, there is also a 200,000-lb., +universal, four-screw testing machine, with miscellaneous equipment for +testing cement and moulding concrete, etc.; and at the Northampton +sub-station, there is a complete equipment of apparatus for cement +testing, capable of handling 10,000 bbl. per day.</p> + +<p> +At the Pittsburg testing station, a 10,000,000-lb., vertical, +compression testing machine (<a href = "#plate_XIV">Plate XIV</a>), +made by Tinius Olsen and Company, is being erected for making a complete +series of comparative tests of various building stones of 2, 4, and +12-in. cube, of stone prisms, 12 in. base and 24 in. high, of concrete +and reinforced concrete columns up to 65 ft. in height, and of brick +piers and structural-steel columns up to the the limits of the capacity +and height of the machine.</p> + +<!--png265--> +<p class = "illustration"> +<span class = "pagenum">[opp. 248]</span> +<a name = "plate_XIV"><span class = "smallcaps">Plate +XIV.</span></a><br> +<img src = "images/plate14.jpg" width = "310" height = "500" +alt = "Plate XIV"><br> +<span class = "smallcaps">10,000,000-Lb. Testing Machine.</span></p> + +<p> +<!--png263--> +<span class = "pagenum">247</span> +<a name = "page247"> </a> +This machine is a large hydraulic press, with an adjustable head, and a +weighing system for recording the loading developed by a triple-plunger +pump. It has a maximum clearance of 65 ft. between heads; the clearance +in the machine is a trifle more than 6 ft. between screws, and the heads +are 6 ft. square.</p> + +<p> +The machine consists of a base containing the main cylinder, with a +sectional area of 2,000 sq. in., upon which rests the lower platform or +head, which is provided with a ball-and-socket bearing. The upper head +is adjustable over four vertical screws, 13½ in. in diameter and 72 ft. +2 in. long, by a system of gearing operating four nuts with +ball-bearings upon which the head rests. The shafting operating this +mechanism is connected with a variable-speed motor which actuates the +triple-plunger pump supplying the pressure to the main cylinder (<a href += "#fig_4">Fig. 4</a>).</p> + +<p class = "illustration"> +<a name = "fig_4"><span class = "smallcaps">Fig. 4.</span></a><br> +<img src = "images/fig4.png" width = "474" height = "586" +alt = "PLAN AND ELEVATION OF 10,000,000-LB. VERTICAL COMPRESSION TESTING MACHINE"></p> + +<p> +The weighing device consists of a set of standard Olsen levers for +weighing one-eightieth of the total load on the main cylinder. This +reduction is effected through the medium of a piston and a diaphragm. +The main cylinder has a diameter of 50 in., and the smaller one, a +diameter of 5 9/16 in. The weighing beam is balanced by an +automatically-operated poise weight, and is provided with a device for +applying successive counterweights of 1,000,000 lb. each. Each division +on the dial is equivalent to a 100-lb. load, and smaller subdivisions +are made possible by an additional needle-beam.</p> + +<p> +The power is applied by a 15-h.p., 220-volt, variable-speed motor +operating a triple-plunger pump, the gearing operating the upper head +being driven by the same motor. The extreme length of the main screws +necessitates splicing, which is accomplished as follows:</p> + +<p> +In the center of the screws, at the splice, is a 3-in. threaded pin for +centering the upper and lower screws; this splice is strengthened by +sleeve nuts, split to facilitate their removal whenever it is necessary +to lower the upper head; after the head has passed the splice, the +sleeve nuts are replaced.</p> + +<p> +In order to maintain a constant load, a needle-valve has been provided, +which, when the pump is operated at its lowest speed, will allow a +sufficient quantity of oil to flow into the main cylinder to equalize +whatever leakage there may be. The main cylinder has a vertical movement +of 24 in. The speed of the machine, for the purpose of adjustment, using +the gearing attached to the upper head, is 10 in. per +<!--png264--> +<span class = "pagenum">248</span> +<a name = "page248"> </a> +min. The speed for applying loads, controlled by the variable-speed +motor driving the pump, varies from a minimum of at least 1/60 in. per +min. to a maximum of at least ½ in. per min. The machine has a +guaranteed accuracy of at least one-third of 1%, for any load of more +than 100,000 lb., up to its capacity.</p> + +<p> +The castings for the base and the top head weigh approximately 48,000 +lb. each. Each main screw weighs more than 40,000 lb., the lower +platform weighing about 25,000 lb., and the main cylinder, 16,000 lb. +The top of the machine will be about 70 ft. above the top +<!--png267--> +<span class = "pagenum">249</span> +<a name = "page249"> </a> +of the floor, and the concrete foundation, upon which it rests, is about +8 ft. below the floor line.</p> + +<p> +<i>Concrete and Cement Investigations.</i>—The investigations +relating to concrete include the examination of the deposits of sand, +gravel, stone, etc., in the field, the collection of representative +samples, and the shipment of these samples to the laboratory for +analysis and test. These tests are conducted in connection with the +investigation of cement mortars, made from a typical Portland cement +prepared by thoroughly mixing a number of brands, each of which must +meet the following requirements:</p> + +<div class = "rules"> +<p> +Specific gravity, not less than 3.10;</p> + +<p> +Fineness, residue not to exceed 8% on No. 100, nor 25% on No. 200 +sieve;</p> + +<p> +Time of setting: Initial set, not less than 30 min.; hard set, not less +than 1 hour, nor more than 10 hours.</p> + +<p> +Tensile strength: Requirements applying to neat cement and to 1 part +cement with 3 parts standard sand:</p> + +<table class = "quotation lines"> +<tr class = "lines"> +<th>Time specification.</th> +<th class = "leftline">Neat cement.<br> +Pounds.</th> +<th class = "leftline">1:3 Mix.<br> +Pounds.</th> +</tr> +<tr> +<td>24 hours in moist air</td> +<td class = "middle leftline">175</td> +<td class = "middle leftline">...</td> +</tr> +<tr> +<td>7 days (1 day in moist air, 6 days in water)</td> +<td class = "middle leftline">500</td> +<td class = "middle leftline">175</td> +</tr> +<tr> +<td>28 days (1 day in moist air, 27 days in water)</td> +<td class = "middle leftline">600</td> +<td class = "middle leftline">250</td> +</tr> +</table> + +<p> +Constancy of volume: Pats of neat cement, 3 in. in diameter, ½ in. thick +at center, tapering to a thin edge, shall be kept in moist air for a +period of 24 hours. A pat is kept in air at normal temperature and +observed at intervals for at least 28 days. Another pat is kept in water +maintained as near 70° Fahr. as practicable, and is observed at +intervals for at least 28 days. A third pat is exposed in an atmosphere +of steam above boiling water, in a loosely-closed vessel, for 5 hours. +These pats must remain firm and hard and show no signs of distortion, +checking, cracking, or disfiguration.</p> + +<p> +The cement shall not contain more than 1.75% of anhydrous sulphuric +acid, nor more than 4% of magnesium oxide.</p> + +<p> +A test of the neat cement must be made with each mortar series for +comparison of the quality of the typical Portland cement.</p> +</div> + +<p> +The constituent materials are subjected to the following examination and +determinations, and, in addition, are analyzed to determine the +composition and character of the stone, sand, etc.:</p> + +<p class = "hanging"> +1.—Mineralogical examination,</p> + +<p class = "hanging"> +2.—Specific gravity,</p> + +<p class = "hanging"> +<!--png268--> +<span class = "pagenum">250</span> +<a name = "page250"> </a> +3.—Weight, per cubic foot,</p> + +<p class = "hanging"> +4.—Sifting (granulometric composition),</p> + +<p class = "hanging"> +5.—Percentage of silt and character of same,</p> + +<p class = "hanging"> +6.—Percentage of voids,</p> + +<p class = "hanging"> +7.—Character of stone as to percentage of absorption, porosity, +permeability, compressive strength, and behavior under treatment.</p> + +<p> +Physical tests are made to determine the tensile, compressive, and +transverse strengths of the cement and mortar test pieces, with various +preparations of cement and various percentages of material. Tests are +also made to determine porosity, permeability, volumetric changes in +setting, absorption, coefficient of expansion, effect of oil, etc.</p> + +<p> +Investigation of concretes made from mixtures of typical Portland +cement, sand, stone, and gravel, includes tests on cylinders, prisms, +cubes, and other standard test pieces, with various proportions of +materials and at ages ranging from 30 to 360 days. Full-sized plain +concrete beams, moulded building blocks, reinforced concrete beams, +columns, floor slabs, arches, etc., are tested to determine the effect, +character, and amount of reinforcement, the effect of changes in volume, +size, and composition, and the effect of different methods of loading +and of supporting these pieces, etc.</p> + +<p> +These investigations include detailed inquiry in the field and research +in the chemical and physical laboratories regarding the effects of +alkaline soils and waters on structures of concrete being built by the +Reclamation Service in the arid regions. It has been noted that on +certain of the Reclamation projects, notably on the Sun River Project, +near Great Falls, Mont., the Shoshone Project, near Cody, Wyo., and the +Carlsbad and Hondo Projects in the Pecos Valley, N. Mex., structures of +concrete, reinforced concrete, building stones, brick, and tile, show +evidence of disintegration. This is attributed to the effects of +alkaline waters or soils coming into contact with the structures, or to +the constituent materials used. In co-operation with the Reclamation +Service, samples of the waters, soils, and constituent materials, are +collected in the field, and are subjected to careful chemical +examination in the mineral laboratories at Pittsburg.</p> + +<!--png269--> +<p class = "illustration"> +<span class = "pagenum">[opp. 250]</span> +<a name = "plate_XV"><span class = "smallcaps">Plate XV.</span></a><br> +<img src = "images/plate15a.jpg" width = "500" height = "375" +alt = "Plate XV Fig. 1"><br> +<span class = "smallcaps">Fig. 1.—Characteristic Failures of +Reinforced Concrete Beams.</span><br> +<img src = "images/plate15b.jpg" width = "500" height = "353" +alt = "Plate XV Fig. 2"><br> +<span class = "smallcaps">Fig. 2.—Arrangement of Static Load Test +for Reinforced Concrete Beams.</span></p> + +<p> +The cylinders used in the percolation tests are composed of typical +Portland cement mixed with sand, gravel, and broken stone of known +composition and behavior, and of cement mixed with sand, gravel, and +<!--png271--> +<span class = "pagenum">251</span> +<a name = "page251"> </a> +broken stone collected in the neighborhood of the Reclamation projects +under investigation.</p> + +<p class = "illustration float"> +<a name = "fig_5"><span class = "smallcaps">Fig. 5.</span></a><br> +<img src = "images/fig5.png" width = "271" height = "494" +alt = "CROSS-SECTION OF APPARATUS FOR HOLDING PERMEABILITY-TEST PIECES"></p> + +<p>It is also proposed to subject these test pieces, some made with +water of known purity, and others with alkaline water, to contact with +alkaline soils near the projects, and with soil of known composition +near the testing laboratories at Pittsburg. As these tests progress and +other lines of investigation are developed, the programme will be +extended, in the hope that the inquiry may develop methods of preparing +and mixing concrete and reinforced concrete which can be used in +alkaline soils without danger of disintegration.</p> + +<p> +Investigations into the effect of salt water on cement mortars and +concretes, and the effect of electrolysis, are being conducted at +Atlantic City, N. J., where the test pieces may be immersed in deep +sea water for longer or shorter periods of time.</p> + +<p> +At the Pittsburg laboratory a great amount of investigative work is done +for the purpose of determining the suitability and availability of +various structural materials submitted for use by the Government. While +primarily valuable only to the Government, the results of these tests +are of indirect value to all who are interested in the use of similar +materials. Among such investigations have been those relating to the +strength, elasticity, and chemical properties of wire rope for use in +the Canal Zone; investigations of the suitability and cementing value of +concrete, +<!--png272--> +<span class = "pagenum">252</span> +<a name = "page252"> </a> +sand, stone, and pozzuolanic material found on the Isthmus; +investigations as to the relative resistance to corrosion of various +types of wire screens for use in the Canal Zone; into the suitability +for use, in concrete sea-wall construction, of sand and stone from the +vicinity of San Francisco; into the properties of reinforced concrete +floor slabs; routine tests of reinforcing metal, and of reinforced +concrete beams and columns, for the Supervising Architect of the +Treasury Department, etc. The results have been set forth in three +bulletins<a class = "tag" name = "tag9" href = "#note9">9</a> which +describe the methods of conducting these tests and also tests on +constituent materials of concrete and plain concrete beams. In addition, +there are in process of publication a number of bulletins giving the +results of tests on reinforced concrete beams, columns, and floor slabs, +concrete building blocks, etc.</p> + +<p> +The Northampton laboratory was established because it is in the center +of the Lehigh cement district, and therefore available for the mill +sampling and testing of purchases of cement made by the Isthmian Canal +Commission; it is also available for tests of cement purchased in the +Lehigh district by the Supervising Architect and others. It is in a +building, the outer walls of which are of cement plaster applied over +metal lath nailed to studding. The partitions are of the same +construction, and the floors and roof are of concrete throughout.</p> + +<p> +The inspection at the factories and the sampling of the cement are under +the immediate direction of the Commission; the testing is under the +direction of the U. S. Geological Survey. A large force of +employees is required, in view of the magnitude of the work, which +includes the daily testing of consignments ranging from 5,000 to 10,000 +bbl., sampled in lots of 100 bbl., which is equivalent to from 50 to 100 +samples tested per day.</p> + +<p> +The cement to be sampled is taken from the storage bins and kept under +seal by the chief inspector pending the results of the test. The +quantity of cement sampled is sufficient for the tests required under +the specifications of the Isthmian Canal Commission, as well as for +preliminary tests made by the cement company, and check tests made at +the Geological Survey laboratory, at Pittsburg.</p> + +<p> +The tests specified by the Commission include determination of +<!--png273--> +<span class = "pagenum">253</span> +<a name = "page253"> </a> +specific gravity, fineness of grinding, time of setting, soundness, +tensile strength (with three parts of standard quartz sand for 7 and 28 +days, respectively), and determination of sulphur anhydride +(SO<sub>3</sub>), and magnesia (MgO).</p> + +<p> +The briquette-making and testing room is fitted with a mixing table, +moist closet, briquette-storage tanks, and testing machines. The mixing +table has a concrete top, in which is set plate glass, 18 in. square and +1 in. thick. Underneath the table are shelves for moulds, glass plates, +etc.</p> + +<p> +The moist closet, 5 ft. high, 3 ft. 10 in. wide, and 1 ft. 8 in. deep, +is divided into two compartments by a vertical partition, and each +compartment is fitted with cleats for supporting thirteen tiers of glass +plates. On each pair of cleats, in each compartment, can be placed four +glass plates, each plate containing a 4-gang mould, making storage for +416 briquettes. With the exception of the doors, which are of wood lined +with copper, the closet is of 1:1 cement mortar, poured monolithic, even +to the cleats for supporting the glass plates.</p> + +<p> +The immersion tanks, of the same mortar, are in tiers of three, +supported by a steel structure. They are 6¼ ft. long, 2¼ ft. wide, and 6 +in. deep, and 2,000 briquettes can be stored in each tank. The overflow +from the top tank wastes into the second, which, in turn, wastes into +the third. Water is kept running constantly.</p> + +<p> +The briquette-testing machine is a Fairbanks shot machine with a +capacity of 2,000 lb., and is regulated to apply the load at the rate of +600 lb. per min. Twenty-four 4-gang moulds, of the type recommended by +the Special Committee on Uniform Tests of Cement, of the American +Society of Civil Engineers, are used.</p> + +<p> +The room for noting time of set and soundness is fitted with a mixing +table similar to that in the briquette-making room. The Vicat apparatus +is used for determining the normal consistency, and the Gilmore +apparatus for the time of setting. While setting, the soundness pats are +stored in galvanized-iron pans having about 1 in. of water in the +bottom, and covered with dampened felt or burlap. The pats rest on a +rack slightly above the water and well below the felt.</p> + +<p> +For specific gravity tests, the Le Chatelier bottles are used. A pan, in +which five bottles can be immersed at one time, is used for maintaining +the benzine at a constant temperature. The samples are weighed on a pair +of Troemner’s No. 7 scales.</p> + +<p> +<!--png274--> +<span class = "pagenum">254</span> +<a name = "page254"> </a> +The fineness room is fitted with tables, two sets of standard No. 100 +and No. 200 sieves, and two Troemner’s No. 7 scales similar to those +used for the specific gravity tests.</p> + +<p> +The storage room is fitted with shelves for the storage of samples being +held for 28-day tests.</p> + +<p> +The mould-cleaning room contains tables for cleaning moulds, and racks +for air pats.</p> + +<p> +An effort is made to keep all the rooms at a temperature of 70° Fahr., +and, with this in view, a Bristol recording thermometer is placed in the +briquette-room. Two wet-and-dry bulb hygrometers are used to determine +the moisture in the air.</p> + +<p> +Samples are taken from the conveyor which carries the cement to the +storage bins, at the approximate rate of one sample for each 100 bbl. +After each 4,000-bbl. bin has been filled, it is sealed until all tests +have been made, when, if these have been satisfactory, it is released +for shipment.</p> + +<p> +The samples are taken in cans, 9 in. high and 7½ in. in diameter. These +cans are delivered in the preparation room where the contents are mixed +and passed through a No. 20 sieve. Separate samples are then weighed out +for mortar briquettes, for soundness pats, and for the specific-gravity +and fineness tests. These are placed in smaller cans and a quantity +sufficient for a re-test is held in the storage room awaiting the +results of all the tests.</p> + +<p> +The sample for briquettes is mixed with three parts standard crushed +quartz, and then taken to the briquette-making room, where eight +briquettes are made, four for 7-day and four for 28-day tests. These are +placed in the moist closet in damp air for 24 hours, then removed from +the moulds, and placed in water for the remainder of the test period. At +the proper time they are taken from the immersion tank and broken.</p> + +<p> +From the sample for soundness, four pats are made. The time of setting +is determined on one of these pats. They are placed in the pan +previously described, for 24 hours, then one is placed in running water +and one in air for 28 days. The others are treated in the boiler, one in +boiling water for 3 hours and one in steam at atmospheric pressure for 5 +hours.</p> + +<p> +The sample taken for specific gravity and fineness is dried in the oven +at 100° cent. in order to drive off moisture. Two samples are then +carefully weighed out, 50 grammes for fineness and 64 grammes +<!--png275--> +<span class = "pagenum">255</span> +<a name = "page255"> </a> +for specific gravity, and the determinations are made. As soon as +anything unsatisfactory develops, a re-test is made. If, however, the +cement satisfies all requirements, a report sheet containing all the +data for a bin, is made out, and the cement is ready for shipment. From +every fifth bin, special neat and mortar briquettes are made, which are +intended for tests at ages up to ten years.</p> + +<p> +<i>Salt-Water Laboratory.</i>—The laboratory at Atlantic City, for +conducting investigations into the effects of salt water on concrete and +reinforced concrete, is situated so that water more than 25 ft. deep is +available for immersion tests of the setting and deterioration of such +materials.</p> + +<p> +Through the courtesy of the municipality of Atlantic City, Young’s +cottage, on old Young’s Pier, has been turned over, at a nominal rental, +to the Geological Survey for the conduct of these tests. The laboratory +building is about 700 ft. from the boardwalk, and occupies a space about +100 by 45 ft. It is one story high, of frame-cottage construction, and +stands on wooden piles at one side of the pier proper and about 20 ft. +above the water, which is about 19 ft. deep at this point. Fresh running +water, gas, electric light, and electric power are supplied to the +building (<a href = "#fig_6">Fig. 6</a>).</p> + +<!--png277--> +<p class = "illustration"> +<span class = "pagenum">[257]</span> +<a name = "page257"> </a> +<a name = "fig_6"><span class = "smallcaps">Fig. 6.</span></a><br> +<a href = "images/fig6.png"> +<img src = "images/thumb6.png" width = "288" height = "133" +alt = "Figure 6 thumbnail"></a><br> +<span class = "caption"> +PLAN OF LABORATORY FOR SALT-WATER TESTS AT ATLANTIC CITY, N. +J.</span></p> + +<p> +In this laboratory investigations will be made of the cause of the +failure and disintegration of cement and concrete subjected to the +action of sea water. Tests are conducted so as to approach, as nearly as +possible, the actual conditions found in concrete construction along the +sea coast. All sea-water tests are made in the ocean, some will probably +be paralleled by ocean-water laboratory tests and all by fresh-water +comparative tests.</p> + +<p> +Cements, in the form of pats, briquettes, cubes, cylinders, and in a +loose ground state, and also mortars and concretes in cube, cylinder, +and slab form, are subjected to sea water.</p> + +<p> +The general plan for the investigations is as follows:</p> + +<p> +1.—Determination of the failing elements and the nature of the +failure;</p> + +<p> +2.—Determination of the value of the theories advanced at the +present time; and,</p> + +<p> +3.—Determination of a method of eliminating or chemically +recombining the injurious elements.</p> + +<p> +Preliminary tests are in progress, including a study of the effect of +salt water on mortars and concretes of various mixtures and ages. +<!--png276--> +<span class = "pagenum">256</span> +<a name = "page256"> </a> +The proportions of these mixtures and the methods of mixing will be +varied from time to time, as suggested by the progress of the tests.</p> + +<p> +<i>Fire-Proofing Tests.</i>—Tests of the fire-proofing and +fire-resistive properties of various structural materials are carried on +in the laboratories in Building No. 10, at Pittsburg, and in +co-operation with the Board or Fire Underwriters at its Chicago +laboratory (Fig. 2, <a href = "#plate_XIII">Plate XIII</a>). These +tests include three essential classes of material: (<i>a</i>), clay +products, protective coverings representative of numerous varieties of +brick and fire-proofing tiles, including those on the market and those +especially manufactured for these tests in the laboratory at Pittsburg; +(<i>b</i>), characteristic granites of New England, with subsequent +tests of the various building stones found throughout the United States; +and (<i>c</i>), cement and concrete covering material, building blocks, +and concrete reinforced by steel bars embedded at different depths for +the purpose of studying the effect of expansion on the protective +covering.</p> + +<p> +In co-operation with the physical laboratory, these tests include a +study of the relative rates of conductivity of cement mortars and +concretes. By embedding thermo-couples in cylinders composed of the +materials under test, obtaining a given temperature by an electric coil, +and noting the time required to raise the temperature at the various +embedded couples to a given degree, the rate of conductivity may be +determined. Other tests include those in muffles to determine the rate +of expansion and the effect of heat and compressive stresses combined on +the compressive strength of the various structural materials. The +methods of making the panel tests, and the equipment used, are described +and illustrated in Bulletin No. 329, and the results of the tests have +been published in detail.<a class = "tag" name = "tag10" href = +"#note10">10</a></p> + +<p> +<i>Building Stones Investigations.</i>—The field investigations of +building stones are conducted by Mr. E. F. Burchard, and include +the examination of the various deposits found throughout the United +States. A study of the granites of New England has been commenced, which +includes the collection of type specimens of fine, medium, and +coarse-grained granites, and of dark, medium, and light-gray or white +granites. A comparative series of these granites, consisting of prisms +and cubes of 4 and 2 in., respectively, has been prepared.</p> + +<p> +<!--png278--> +<span class = "pagenum">258</span> +<a name = "page258"> </a> +The standard adopted for compressive test pieces in the 10,000,000-lb. +machine is a prism, having a base of 12 in. and being 24 in. high. The +tests include not only those for compression or crushing strength, but +also those for resistance to compressive strains of the prisms and +cubes, when raised to high temperatures in muffles or kilns; resistance +to weathering, freezing, and thawing; porosity; fire-resisting +qualities, etc.</p> + +<p> +In collecting field samples, special attention is paid to the occurrence +of the stone, extent of the deposit, strike, dip, etc., and specimens +are procured having their faces cut with reference to the bedding +planes, in order that compressive and weathering tests may be made, not +only in relation to these planes but at those angles thereto in which +the material is most frequently used commercially. Attention is also +paid to the results of blasting, in its relation to compressive strains, +as blasting is believed to have a material effect on stones, especially +on those which may occur in the foundations of great masonry dams, and +type specimens of stone quarried by channeling, as well as by blasting, +are collected and tested.</p> + +<p> +<i>Clay and Clay Products Investigations.</i>—These investigations +are in charge of Mr. A. V. Bleininger, and include the study of the +occurrence of clay beds in various parts of the United States, and the +adaptability of each clay to the manufacture of the various clay +products.</p> + +<p> +Experiments on grinding, drying, and burning the materials are conducted +at the Pittsburg testing station, to ascertain the most favorable +conditions for preparing and burning each clay, and to determine the +most suitable economic use to which it may be put, such as the +manufacture of building or paving bricks, architectural tiles, sewer +tiles, etc.</p> + +<p> +The laboratory is equipped with various grinding and drying devices, +muffles, kilns, and apparatus for chemical investigations, physical +tests, and the manufacture and subsequent investigative tests of clay +products.</p> + +<p> +This section occupies the east end of Building No. 10, and rooms on the +first and second floors have been allotted for this work. In addition, a +brick structure, 46 by 30 ft., provided with a 60-ft. iron stack, has +been erected for housing the necessary kilns and furnaces.</p> + +<p> +On the ground floor of Building No. 10, adjoining the cement and +<!--png281--> +<span class = "pagenum">259</span> +<a name = "page259"> </a> +concrete section, is a storage room for raw materials and product under +investigation. Adjoining this room, and connecting with it by wide +doors, is the grinding room, containing a 5-ft. wet pan, with 2,000-lb. +rollers, to be used for both dry and wet grinding. Later, a heavy dry +pan is to be installed. With these machines, even the hardest material +can be easily disintegrated and prepared. In this room there is also a +jaw crusher for reducing smaller quantities of very hard material, as +well as a 30 by 16-in. iron ball mill, for fine grinding. These machines +are belted to a line shaft along the wall across the building. Ample +sink drainage is provided for flushing and cleaning the wet pan, when +changing from one clay to another.</p> + +<p> +A large room adjoining is for the operation of all moulding and shaping +machines, representing the usual commercial processes. At present these +include an auger machine, with a rotary universal brick and tile cutter, +Fig. 1, <a href = "#plate_XVI">Plate XVI</a>, and a set of brick +and special dies, a hand repress for paving brick, and a hand screw +press for dry pressing. The brick machine is operated from the main +shaft which crosses the building in this room and is driven from a +50-h.p. motor. It is possible thus to study the power consumption under +different loads and with different clays, as well as with varying +degrees of water content in the clay. As the needs of the work demand +it, other types of machines are to be installed. For special tests in +which pressure is an important factor it is intended to fit up one of +the compression testing machines of the cement section with the +necessary dies, thus enabling the pressing to be carried on under known +pressures. Crushing, transverse, and other tests of clay products are +made on the testing machines of the cement and concrete +laboratories.</p> + +<!--png279--> +<p class = "illustration"> +<span class = "pagenum">[opp. 258]</span> +<a name = "plate_XVI"><span class = "smallcaps">Plate +XVI.</span></a><br> +<img src = "images/plate16a.jpg" width = "500" height = "385" +alt = "Plate XVI Fig. 1"><br> +<span class = "smallcaps">Fig. 1.—Brick Machine and Universal +Cutter.</span><br> +<img src = "images/plate16b.jpg" width = "500" height = "374" +alt = "Plate XVI Fig. 2"><br> +<span class = "smallcaps">Fig. 2.—House-Heating Boilers, Building +No. 21.</span></p> + +<p> +Outside of the building, in a lean-to, there is a double-chamber rattler +for the testing of paving brick according to the specifications of the +National Brick Manufacturers’ Association.</p> + +<p> +In the smaller room adjoining the machine laboratory there are two small +wet-grinding ball mills, of two and four jars, respectively, and also a +9-leaf laboratory filter press.</p> + +<!--png283--> +<p class = "illustration float"> +<span class = "pagenum">[261]</span> +<a name = "page261"> </a> +<a name = "fig_7"><span class = "smallcaps">Fig. 7.</span></a><br> +<a href = "images/fig7.png"> +<img src = "images/thumb7.png" width = "180" height = "288" +alt = "Figure 7 thumbnail"></a><br> +<span class = "caption"> +CLAY-DRYING OVEN</span></p> + +<p> +The remaining room on the first floor is devoted to the drying of clays +and clay wares. The equipment consists of a large sheet-iron drying oven +of special construction, which permits of close regulation of the +temperature (<a href = "#fig_7">Fig. 7</a>). It is heated by gas +burners, and is used for the preliminary heat treatment of raw clays, in +connection with +<!--png282--> +<span class = "pagenum">260</span> +<a name = "page260"> </a> +the study of the drying problems of certain raw materials. It is +intended to work with temperatures as high as 250° cent.</p> + +<p> +Another drying closet, heated by steam coils (<a href = +"#fig_8">Fig. 8</a>), intended for drying various clay products, +has been designed with special reference to the exact regulation of the +temperature, humidity, and velocity of the air flowing through it. Both +dryers connect by flues with an iron stack outside the building. This +stack is provided with a suction fan, driven by a belt from an electric +motor.</p> + +<p> +On the second floor are the chemical, physical, and research +laboratories, dealing with the precise manipulations of the tests and +investigations.</p> + +<p class = "illustration"> +<a name = "fig_8"><span class = "smallcaps">Fig. 8.</span></a><br> +<img src = "images/fig8.png" width = "477" height = "328" +alt = "Figure 8"><br> +<span class = "caption"> +DRYING CLOSETS FOR CERAMICS</span></p> + +<p> +The chemical laboratory is fully equipped with the necessary apparatus +for carrying on special chemical research in silicate chemistry, +including electrical resistance furnaces, shaking devices, etc. It is +not the intention to do routine work in this laboratory. The office +adjoins this laboratory, and near it is the physical laboratory, devoted +to the study of the structure of raw materials. The latter contains +Nobel and Schoene elutriators, together with viscosimeters of the flow +and the Coulomb and Clark electrical types, sieves, voluminometers, +colorimeters, vernier shrinkage gauges, micrometers, microscopes, and +the necessary balances.</p> + +<p> +The room across the hall is devoted to the study of the specific +gravity, absorption, porosity, permeability, hardness, translucency, +etc., of burnt-clay products, all the necessary apparatus being +provided. In the two remaining rooms, intended for research work, +special apparatus adapted to the particular investigation may be set up. +All the rooms are piped for water, gas, compressed air, steam, and +drainage, and wired for light and power.</p> + +<p> +In the kiln house there is a test kiln adapted for solid fuel and gas. +It is of the down-draft type, with an available burning space of about 8 +cu. ft. (<a href = "#fig_9">Fig. 9</a>). For heavier ware and the +study of the fire behavior of clay products under conditions approaching +those of practice, a round down-draft kiln, with an inside diameter of 6 +ft., is installed. About 13 ft. above the floor level, and supported by +iron beams, there is a flue parallel to the long side of the structure. +This flue conducts the gases of the kilns to the stack, which is +symmetrically located with reference to the kiln house. Natural gas is +the principal fuel. In addition to these kilns, a small muffle furnace, +fired with +<!--png284--> +<span class = "pagenum">262</span> +<a name = "page262"> </a> +petroleum, is provided for the determination of melting points, and an +electric carbon resistance furnace, with an aluminum muffle for +high-temperature work. For crucible-fusion work, a gas-fired pot furnace +is installed.</p> + +<p class = "illustration"> +<a name = "fig_9"><span class = "smallcaps">Fig. 9.</span></a><br> +<img src = "images/fig9.png" width = "465" height = "405" +alt = "Figure 9"><br> +<span class = "caption"> +DOWN-DRAFT KILN</span></p> + +<p> +Along the north wall, bins are provided for the storage of fuel, clay, +sand, and other kiln supplies. There are two floor drainage sinks, and +electric current, steam, water, and compressed air, are provided.</p> + +<p> +<i>Results of the Work.</i>—More than 39,300 separate test pieces +have been made at the structural-materials testing laboratory. In +connection with the study of these, 86,000 tests and nearly 14,000 +chemical analyses have been made. Of these tests more than 13,600 have +been of the constituent materials of concrete, including tensile tests +of cement briquettes, compression tests of cylinders and cubes, and +transverse tests of various specimens.</p> + +<p> +Nearly 1,200 beams of concrete or reinforced concrete, each 13 ft. long +and 8 by 11 in. in cross-section, have been made, and, in connection +with the investigation of the behavior of these beams, nearly 3,000 +tests have been made. Nearly 900 of these beams, probably more than +double the entire number made in other laboratories in +<!--png285--> +<span class = "pagenum">263</span> +<a name = "page263"> </a> +the United States, during a period of more than 15 years, have been +tested.</p> + +<p> +In the section of building blocks, 2,200 blocks have been tested, +including, with auxiliary pieces, more than 4,500 tests; also, more than +900 pieces of concrete have been tested for permeability and shear. The +physical tests have numbered 14,000; tests of steel for reinforcement, +3,800; and 550 tests to determine fire-resistive qualities of various +building materials, have been made on 30 special panels, and on +miscellaneous pieces.</p> + +<p> +The tests of the permeability of cement mortars and concretes, and of +water-proofing and damp-proofing materials, have numbered 3,470.</p> + +<p> +The results of the work of the Structural Materials Division have +already appeared in preliminary bulletins, as follows: No. 324, “San +Francisco Earthquake and Fire of April 18, 1906, and Their Effects on +Structures and Structural Materials”; No. 329, “Organization, Equipment, +and Operation of the Structural-Materials Testing Laboratories +<!--png286--> +<span class = "pagenum">264</span> +<a name = "page264"> </a> +at St. Louis, Mo.”; No. 331, “Portland Cement Mortars and Their +Constituent Materials” (based on nearly 25,000 tests); No. 344, +“Strength of Concrete Beams” (based on tests of 108 beams); No. 370, +“Fire-Resistive Properties of Various Building Materials”; No. 387, “The +Colloid Matter of Clay and its Measurements.” A bulletin on the results +of tests of reinforced concrete beams, one on the manufacture and +chemistry of lime, and one on drying tests of brick, are in course of +publication.</p> + + +<h5 class = "smallcaps">Fuel Investigations.</h5> + +<p> +The scope of the fuel investigations has been planned to conform to the +provisions of the Act of Congress which provides for analyzing and +testing coals, lignites, and other mineral fuel substances belonging to +the United States, or for the use of the United States Government, and +examinations for the purpose of increasing the general efficiency or +available supply of the fuel resources in the United States.</p> + +<p> +In conformity with this plan, the investigations inaugurated at St. +Louis had for their initial object the analyzing and testing of the +coals of the United States, using in this work samples of from 1 to 3 +carloads, collected with great care from typical localities in the more +important coal fields of the country, with a view to determining the +relative values of those different fuels. In the work at Norfolk, during +1907, this purpose was modified to the extent of keeping in view +relative fuel efficiencies for naval purposes. The tests at Denver have +been on coal from Government land or from land contiguous thereto, and +are conducted solely with a view to perfecting methods of coking this +coal by prior washing and by manipulation in the process of coking.</p> + +<p> +Three general lines of inquiry are embodied in the plan of investigation +undertaken and contemplated by the Technologic Branch, after conference +and with the advice and approval of the Advisory Board: 1. The +ascertainment of the best mode of utilizing any fuel deposit owned or to +be used by the Government, or the fuel of any extensive deposit as a +whole, by conducting a more thorough investigation into its combustion +under steam boilers, conversion into producer gas, or into coke, +briquettes, etc. 2. The prevention of waste, through the study of the +possibility of improvement in the methods of mining, shipping, +utilizing, etc. 3. The inspection and analysis of coal and +<!--png287--> +<span class = "pagenum">265</span> +<a name = "page265"> </a> +lignite purchased under specification for the use of the Government, to +ascertain its heating value, ash, contained moisture, etc.</p> + +<p> +The first general line of work concerns the investigation and testing of +the fuel resources of the United States, and especially those belonging +to the Federal Government, to determine a more efficient and more +economical method of utilizing the same. This work has developed along +the following lines:</p> + +<p> +The collection of representative samples for chemical analysis, and +calorimeter tests by a corps of skilled mine samplers, from the mines +selected as typical of extensive deposits of coal in a given field or +from a given bed of coal; and the collection from the same mines of +larger samples of from 1 to 3 carloads, shipped to the testing station +for tests in boiler furnaces, gas producers, etc., as a check on the +analysis and calorimeter tests;</p> + +<p> +The testing of each coal received to determine the most efficient and +least wasteful method of use in different furnaces suitable for public +buildings or power plants or ships of the Government;</p> + +<p> +The testing of other portions of the same shipment of coal in the gas +producer, for continuous runs during periods of a few days up to several +weeks, in order to determine the availability of this fuel for use in +such producers, and the best method of handling it, to determine the +conditions requisite to produce the largest amount of high-grade gas +available for power purposes;</p> + +<p> +The testing of another portion of the same coal in a briquette machine +at different pressures and with different percentages and kinds of +binder, in order to determine the feasibility of briquetting the slack +or fine coal. Combustion tests are then made of these briquettes, to +determine the conditions under which they may be burned +advantageously;</p> + +<p> +Demonstrations, on a commercial scale, of the possibility of producing +briquettes from American lignites, and the relative value of these for +purposes of combustion as compared with the run-of-mine coal from which +the briquettes are made;</p> + +<p> +The finding of cheaper binders for use in briquetting friable coals not +suited for coking purposes;</p> + +<p> +Investigations into the distribution, chemical composition, and +calorific value of the peat deposits available in those portions of the +United States where coal is not found, and the preparation of such +<!--png288--> +<span class = "pagenum">266</span> +<a name = "page266"> </a> +peat for combustion, by drying or briquetting, to render it useful as a +local substitute for coal;</p> + +<p> +Investigations into the character of the various petroleums found +throughout the United States, with a view to determining their calorific +value, chemical composition, and the various methods whereby they may be +made most economically available for more efficient use as power +producers, through the various methods of combustion;</p> + +<p> +Investigations and tests into the relative efficiency, as power +producers in internal-combustion engines, of the heavier distillates of +petroleum, as well as of kerosene and gasoline, in order to ascertain +the commercial value and relative efficiency of each product in the +various types of engines;</p> + +<p> +Investigations into the most efficient methods of utilizing the various +coals available throughout the United States for heating small public +buildings, army posts, etc., in order that these coals may be used more +economically than at present;</p> + +<p> +Investigative studies into the processes of combustion within boiler +furnaces and gas producers to ascertain the temperatures at which the +most complete combustion of the gases takes place, and the means whereby +such temperatures may be produced and maintained, thus diminishing the +loss of values up the smokestack and the amount of smoke produced;</p> + +<p> +Investigations and tests into the possibilities of coking coals which +have hitherto been classed as non-coking, and the making of comparative +tests of all coals found in the United States, especially those from the +public lands of the West;</p> + +<p> +Investigations, by means of washing in suitable machines, to determine +the possibility of improving the quality of American coals for various +methods of combustion, and with a view to making them more available for +the production of coke of high-grade metallurgical value, as free as +possible from sulphur and other injurious substances.</p> + +<p> +At each stage of the process of testing, samples of the coal have been +forwarded to the chemical laboratory for analyses; combustion +temperatures have been measured; and samples of gas collected from +various parts of the combustion chambers of the gas producers and boiler +furnaces have been analyzed, in order that a study of these data may +throw such light on the processes of combustion and indicate such +necessary changes in the apparatus, as might result in larger economies +in the use of coal.</p> + +<p> +<!--png289--> +<span class = "pagenum">267</span> +<a name = "page267"> </a> +The second line of investigation concerns the methods of mining and +preparing coal for the market, and the collection of mine samples of +coal, oil, etc., for analysis and testing. It is well known that, under +present methods of mining, from 10 to 75% of any given deposit of coal +is left underground as props and supports, or as low-grade material, or +in overlying beds broken up through mining the lower bed first. An +average of 50% of the coal is thus wasted or rendered valueless, as it +cannot be removed subsequently because of the caving or falling in of +the roofs of abandoned galleries and the breaking up of the adjoining +overlying beds, including coal, floor, and roof.</p> + +<p> +The investigations into waste in mining and the testing of the waste, +bone, and slack coal in gas producers, as briquettes, etc., have, for +their purpose, the prevention of this form of waste by demonstrating +that these materials, now wasted, may be used profitably, by means of +gas producers and engines, for power purposes.</p> + +<p> +The third general line of investigation concerns the inspection and +sampling of fuel delivered to the Government under purchase contracts, +and the analyzing and testing of the samples collected, to determine +their heating value and the extent to which they may or may not comply +with the specifications under which they are purchased. The coal +delivered at the public buildings in the District of Columbia is sampled +by special representatives of the Technologic Branch of the Survey. The +taking of similar samples at public buildings and posts throughout the +United States, and the shipment of the samples in hermetically sealed +cans or jars to the chemical laboratory at Washington, is for the most +part looked after by special officers or employees at each place. These +purchases are made, to an increasing extent, under specifications which +provide premiums for coal delivered in excess of standards, and +penalties for deliveries below standards fixed in the specifications. +The standard for bituminous coals is based mainly on the heat units, +ash, and sulphur, while that for anthracite coal is based mainly on the +percentage of ash and the heat units.</p> + +<p> +In connection with all these lines of fuel testing, certain research +work, both chemical and physical, is carried on to determine the true +composition and properties of the different varieties of coal, the +changes in the transformation from peat to lignite, from lignite to +bituminous coal, and from bituminous to anthracite coal, and the +chemical and physical processes in combustion. Experiments are conducted +concerning the destructive distillation of fuels; the by-products of +coking +<!--png290--> +<span class = "pagenum">268</span> +<a name = "page268"> </a> +processes; the spontaneous combustion of coal; the storage of coal, and +the loss in value in various methods of storing; and kindred questions, +such as the weathering of coal. These experiments may yield valuable +results through careful chemical research work supplemented by equally +careful observations in the field.</p> + +<p> +<i>Inspection and Mine Sampling.</i>—In the Geological Survey +Building, at Washington, coal purchased for Government use on a +guaranteed-analysis or heat-value basis, is inspected and sampled.</p> + +<p> +Some of the employees on this work are constantly at the mines taking +samples, or at public works inspecting coal for Government use, while +others are stationed at Washington to look after the deliveries of coal +to the many public buildings, and to collect and prepare samples taken +from these deliveries for analysis, as well as to prepare samples +received from public works and buildings in other parts of the +country.</p> + +<p> +The preparation of these samples is carried on in a room in the basement +of the building, where special machinery has been installed for this +work. <a href = "#fig_10">Fig. 10</a> shows a plan of this room and +the arrangement of the sampling and crushing machinery.</p> + +<p class = "illustration"> +<a name = "fig_10"><span class = "smallcaps">Fig. 10.</span></a><br> +<img src = "images/fig10.png" width = "454" height = "246" +alt = "COAL-SAMPLING ROOM, GEOLOGICAL SURVEY, WASHINGTON, D. C."></p> + +<p> +The crushing of the coal produces great quantities of objectionable +dust, and to prevent this dust from giving trouble outside the sampling +room, the wooden partitions on three sides of the room (the fourth side +being a masonry wall) are completely covered on the outside with +galvanized sheet iron. The only openings to the room are two doors, +which are likewise covered with sheet iron, and provided with broad +<!--png291--> +<span class = "pagenum">269</span> +<a name = "page269"> </a> +flanges of the same material, in order to seal effectually the openings +when the doors are shut. Fresh air is drawn into the room by a fan, +through a pipe leading to the outer air. A dust-collecting system which +carries the coal dust and spent air from the room, consists of an +arrangement of 8-in. and 12-in. pipes leading from hoods, placed over +the crushing machines, to the main furnace stack of the building. The +draft in this stack draws all the dust from the crushers directly +through the hoods to the main pipe, where most of it is deposited.</p> + +<p> +The equipment of the sampling room consists of one motor-driven, baby +hammer crusher, which has a capacity of about 1 ton per hour and crushes +to a fineness of ¼-in. mesh; one adjustable chipmunk jaw crusher, for 5- +and 10-lb. samples; one set of 4½ by 7½-in. rolls, crushing to 60 mesh, +for small samples; one large bucking board, and several different sizes +of riffle samplers for reducing samples to small quantities. The small +crushers are belted to a shaft driven by a separate motor from that +driving the baby crusher.</p> + +<p> +In conducting the inspection of departmental purchases of coal in +Washington, the office is notified whenever a delivery of coal is to be +made at one of the buildings, and an inspector is sent, who remains +during the unloading of the coal. He is provided with galvanized-iron +buckets having lids and locks; each bucket holds about 60 lb. of coal. +In these buckets he puts small quantities of the coal taken from every +portion of the delivery, and when the delivery has been completed, he +locks the buckets and notifies the office to send a wagon for them. The +buckets are numbered consecutively, and the inspector makes a record of +these numbers, the date, point of delivery, quality of coal delivered, +etc. The buckets are also tagged to prevent error. He then reports to +the office in person, or by telephone, for assignment to another point +in the city. All the samples are delivered to the crushing room in the +basement of the Survey Building, to be prepared for analysis.<a class = +"tag" name = "tag11" href = "#note11">11</a></p> + +<p> +Samples taken from coal delivered to points outside of Washington are +taken by representatives of the department for which the coal is being +purchased, according to instructions furnished them, and, from time to +time, the regular inspectors are sent to see that these instructions are +being complied with. These samples are crushed by hand, reduced to about +2 lb. at the point where they are taken, and sent +<!--png292--> +<span class = "pagenum">270</span> +<a name = "page270"> </a> +to Washington, in proper air-tight containers, by mail or express, +accompanied by appropriate descriptions.</p> + +<p> +Each sample is entered in the sample record book when received, and is +given a serial number. For each contract a card is provided giving +information relative to the contract. On this card is also entered the +serial number of each sample of coal delivered under that contract.</p> + +<p> +After the samples are recorded, they are sent to the crushing room, +where they are reduced to the proper bulk and fineness for analysis. +They are then sent, in rubber-stoppered bottles, accompanied by blank +analysis report cards and card receipts, one for each sample, showing +the serial numbers, to the fuel laboratory for analysis. The receipt +card for each sample is signed and returned to the inspection office, +and when the analysis has been made, the analysis report card showing +the result is returned. This result is entered at once on the contract +card, and when all analyses have been received, covering the entire +delivery of coal, the average quality is calculated, and the results are +reported to the proper department.</p> + +<p> +The matter of supplying the Pittsburg plant with fuel for test purposes +is also carried on from the Washington office. Preliminary to a series +of investigations, the kinds and amounts of coal required are decided +on, and the localities from which these coals are to be obtained are +determined. Negotiations are then opened with the mine owners, who, in +most cases, generously donate the coal. When the preliminaries have been +arranged, an inspector is sent to the mine to supervise the loading and +shipment of the coal. This inspector enters the mine and takes, for +chemical analysis, small mine samples which are sent to the laboratory +at Pittsburg in metal cans by mail, accompanied by proper identification +cards. The results of the analysis are furnished to the experts in +charge at the testing plant, for their information and guidance in the +investigations for which the coal was shipped.</p> + +<p> +All samples for testing purposes are designated consecutively in the +order of shipment, “Pittsburg No. 1,” “Pittsburg No. 2,” etc. A complete +record of all shipments is kept on card forms at the Pittsburg plant, +and a duplicate set of these is on file in the inspection office at +Washington.</p> + +<p> +<i>Analysis of Fuels.</i>—The routine analyses of fuel used in the +combustion tests at Pittsburg, and of the gases resulting from +combustion +<!--png293--> +<span class = "pagenum">271</span> +<a name = "page271"> </a> +or from explosions in the testing galleries, or sampled in the mines, +are made in Building No. 21.<a class = "tag" name = "tag12" href = +"#note12">12</a> A small laboratory is also maintained on the second +floor of the south end of Building No. 13, for analyses of gases +resulting from combustion in the producer-gas plant, and from explosions +in Galleries Nos. 1 and 2, etc. From four to six chemists are +continually employed in this laboratory (in 8-hour shifts), during +prolonged gas-producer tests, and three chemists are also employed in +analyzing gases relating to mine explosions.</p> + +<p> +In addition to these gas analyses, there are also made in the main +laboratory, analyses and calorific tests of all coal samples collected +by the Geological Survey in connection with its land-classification work +on the coal lands of the Western States. Routine analyses of mine, car, +and furnace samples of fuels for testing, before and after washing and +briquetting, before coking and the resultant coke, and extraction +analyses of binders for briquettes, etc., are also made in this +laboratory.</p> + +<p> +The fuel-testing laboratory at Washington is equipped with three Mahler +bomb calorimeters and the necessary balances and chemical equipment +required in the proximate analysis of coal. More than 650 deliveries of +coal are sampled each month for tests, representing 50,000 tons +purchased per month, besides daily deliveries, on ship-board, of 550,000 +tons of coal for the Panama Railroad. The data obtained by these tests +furnish the basis for payment. The tests cover deliveries of coal to the +forty odd bureaus, and to the District Municipal buildings in +Washington; to the arsenals at Watertown, Mass., Frankford, Pa., and +Rock Island, Ill.; and to a number of navy yards, through the Bureau of +Yards and Docks; to military posts in various parts of the country; for +the Quartermaster-General’s Department; to the Reclamation Service; to +Indian Agencies and Soldiers’ Homes; to several lighthouse districts; +and to the superintendents of the various public buildings throughout +the United States, through the Treasury Department; etc. During 1909, +the average rate of reporting fuel samples was 540 per month, requiring, +on an average, six determinations per sample, or about 3,240 +determinations per month.</p> + +<p class = "illustration float"> +<a name = "fig_11"><span class = "smallcaps">Fig. 11.</span></a><br> +<img src = "images/fig11.png" width = "291" height = "641" +alt = "PLAN OF CONSTRUCTION DETAILS OF METAL HOOD"></p> + +<p> +<i>Fuel-Research Laboratories.</i>—Smaller laboratories, +occupying, on the average, three rooms each, are located in Building No. +21. One is used for chemical investigations and calorific tests of +petroleum collected from the various oil fields of the United States; +another is used +<!--png294--> +<span class = "pagenum">272</span> +<a name = "page272"> </a> +for investigations relative to the extraction of coal and the rapidity +of oxidization of coals by standard solutions of oxidizing agents; and +another is occupied with investigations into the destructive +distillation of coal. The researches under way show the wide variation +in chemical composition and calorific value of the various crude oils, +indicate the possibility of the extraction of coal constituents by +solvents, and point to important results relative to the equilibrium of +gases at high temperatures in furnaces and gas producers. The +investigations also bear directly on the coking processes, especially +the by-product process, as showing the varying proportion of each of the +volatile products derivable from types of coals occurring in the various +coal fields of the United States, the time and temperature at which +these distillates are given off, the variation in quality and quantity +of the products, according to the conditions of temperature, and, in +addition, explain the deterioration of coals in storage, etc.</p> + +<p>At the Washington office, microscopic investigations into the life +history of coal, lignite, and peat are being conducted. These +investigations have already progressed far enough to admit of the +identification of some of the botanical constituents of the older peats +and the younger lignites, and it is believed that the origin of the +older lignites, and even of some of the more recent bituminous coals, +may be developed through this examination.</p> + +<p>In the chemical laboratories, in Building No. 21, the hoods (Figs. <a +href = "#fig_11">11</a> and <a href = "#fig_12">12</a>) are of +iron, with a brick pan underneath. They are supported on iron pipes, as +are most of the other fixtures in the laboratories +<!--png296--> +<span class = "pagenum">274</span> +<a name = "page274"> </a> +in this building. The hood proper is of japanned, pressed-iron plate, +No. 22 gauge, the same material being used for the boxes, slides, and +bottom surrounding the hood. The sash is hung on red copper pulleys, and +the corners of the hood are reinforced with pressed, japanned, riveted +plate to which the ventilating pipe is riveted.</p> + +<!--png295--> +<p class = "illustration"> +<span class = "pagenum">[273]</span> +<a name = "page273"> </a> +<a name = "fig_12"><span class = "smallcaps">Fig. 12.</span></a><br> +<img src = "images/fig12.png" width = "475" height = "668" +alt = "Figure 12"><br> +<span class = "caption"> +ELEVATION OF CONSTRUCTION DETAILS OF METAL HOOD</span></p> + +<p> +There is some variety in the cupboards and tables provided in the +various laboratories, but, in general, they follow the design shown in +<a href = "#fig_13">Fig. 13</a>. The table tops, 12 ft. long, are +of clear maple in full-length pieces, ⅞ in. thick and 2⅝ in. wide, laid +on edge and drilled at 18-in. intervals for bolts. These pieces are +glued and drawn together by the bolts, the heads of which are +countersunk. The tops, planed off, sanded, and rounded, are supported on +pipe legs and frames of 1¼ by 1½-in. galvanized-iron pipe with screw +flanges fitting to the floor and top. Under the tops are drawers and +above them re-agent shelves. Halfway between the table top and the floor +is a wire shelf of a frame-work of No. 2 wire interlaced with No. 12 +weave of ⅝-in. square mesh.</p> + +<!--png297--> +<p class = "illustration"> +<span class = "pagenum">[275]</span> +<a name = "page275"> </a> +<a name = "fig_13"><span class = "smallcaps">Fig. 13.</span></a><br> +<img src = "images/fig13.png" width = "437" height = "369" +alt = "PLAN OF CONSTRUCTION DETAILS OF REAGENT TABLES BUILDING 21."></p> + +<p> +Certain of the tables used in the laboratory are fitted with cupboards +beneath and with drawers, and, in place of re-agent stands, +porcelain-lined sinks are sunk into them. These tables follow, in +general style and construction, the re-agent tables. The tables used in +connection with calorimeter determinations are illustrated in <a href = +"#fig_14">Fig. 14</a>. The sinks provided throughout these +laboratories are of standard porcelain enamel, rolled rim, 18 by 13 in., +with enameled back, over a sink and drain board, 24 in. long on the left +side, though there are variations from this type in some instances.</p> + +<p class = "illustration"> +<a name = "fig_14"><span class = "smallcaps">Fig. 14.</span></a><br> +<img src = "images/fig14.png" width = "428" height = "377" +alt = "Figure 14"><br> +<span class = "caption"> +CONSTRUCTION DETAILS OF CALORIMETER TABLES</span></p> + +<p> +The plumbing includes separate lines of pipe to each hood and table; one +each for cold water, steam at from 5 to 10 lb. pressure, compressed air, +natural gas, and, in some cases, live steam at a pressure of +60 lb.</p> + +<p> +On each table is an exposed drainage system of 2½-in. galvanized-iron +pipe, in the upper surface of which holes have been bored, through which +the various apparatus drain by means of flexible connections of glass or +rubber. These pipes and the sinks, etc., discharge into main drains, +hung to the ceiling of the floor beneath. These drains are of wood, +asphaltum coated, with an inside diameter ranging from 3 to 6 in., and +at the proper grades to secure free discharge. These wooden drain-pipes +are made in short lengths, strengthened by a spiral wrapping of metal +bands, and are tested to a pressure of 40 lb. per sq. in. Angles are +turned and branches connected in 4- and 6-in. square headers.</p> + +<p> +<!--png298--> +<span class = "pagenum">276</span> +<a name = "page276"> </a> +The entire building is ventilated by a force or blower fan in the +basement, and by an exhaust fan in the attic with sufficient capacity to +insure complete renewal of air in each laboratory once in +20 min.</p> + +<p> +The blower fan is placed in the center of the building, on the ground +floor, and is 100 in. in diameter. Its capacity is about 30,000 cu. ft. +of air per min., and it forces the air, through a series of pipes, into +registers placed in each of the laboratories.</p> + +<p> +The exhaust fan, in the center of the attic, is run at 550 rev. per +min., and has a capacity of 22,600 cu. ft. of air per min. It draws the +air from each of the rooms below, as well as from the hoods, through a +main pipe, 48 in. in diameter.</p> + +<p> +<i>Steaming and Combustion Tests.</i>—The investigations included +under the term, fuel efficiency, relate to the utilization of the +various types of fuels found in the coal and oil fields, and deal +primarily with the combustion of such fuels in gas producers, in the +furnaces of steam boilers, in locomotives, etc., and with the efficiency +and utilization of petroleum, kerosene, gasoline, etc., in +internal-combustion engines. This work is under the general direction of +Mr. R. L. Fernald, and is conducted principally in Buildings Nos. +13 (<a href = "#plate_XVII">Plate XVII</a>) and 21.</p> + +<p class = "illustration"> +<span class = "pagenum">[fold-in]</span> +<a name = "plate_XVII"><span class = "smallcaps">Plate +XVII.</span></a><br> +<a href = "images/plate17.png"> +<img src = "images/thumb_p17.png" width = "288" height = "122" +alt = "Plate XVII thumbnail"></a><br> +<span class = "caption">PLAN OF BUILDING 13,<br> +TESTING STATION AT PITTSBURG, PA.</span></p> + +<p> +For tests of combustion of fuels purchased by the Government, the +equipment consists of two Heine, water-tube boilers, each of 210 h.p., +set in Building No. 13. One of these boilers is equipped with a Jones +underfeed stoker, and is baffled in the regular way. At four points in +the setting, large pipes have been built into the brick wall, to permit +making observations on the temperature of the gas, and to take samples +of the gas for chemical analysis.</p> + +<p> +The other boiler is set with a plain hand-fired grate. It is baffled to +give an extra passage for the gases (<a href = +"#fig_15">Fig. 15</a>). Through the side of this boiler, at the +rear end, the gases from the long combustion chamber (<a href = +"#plate_XVIII">Plate XVIII</a>) enter and take the same course as +those from the hand-fired grate. Both the hand-fired grate and the long +combustion chamber may be operated at the same time, but it is expected +that usually only one will be in operation. A forced-draft fan has been +installed at one side of the hand-fired boiler, to provide air pressure +when coal is being burned at high capacity. This fan is also connected +in such a way as to furnish air for the long combustion chamber when +desired. A more complete description of the boilers may be found in +Professional Paper No. 48, and Bulletin No. 325 of +<!--png299--> +<span class = "pagenum">277</span> +<a name = "page277"> </a> +the U. S. Geological Survey, in which the water-measuring apparatus +is also described.<a class = "tag" name = "tag13" href = +"#note13">13</a></p> + +<p class = "illustration"> +<a name = "fig_15"><span class = "smallcaps">Fig. 15.</span></a><br> +<img src = "images/fig15.png" width = "469" height = "371" +alt = "SETTING FOR 210-HORSE POWER, HAND-FIRED BOILERS"></p> + +<p> +On account of the distance from Building No. 21 to the main group of +buildings, it was considered inadvisable to attempt to furnish steam +from Building No. 13 to Building No. 21, either for heating or power +purposes. In view, moreover, of the necessity of installing various +types and sizes of house-heating boilers, on account of tests to be made +thereon in connection with these investigations, it was decided to +install these boilers in the lower floor of Building No. 21, where they +could be utilized, not only in making the necessary tests, but in +furnishing heat and steam for the building and the chemical laboratories +therein.</p> + +<p> +In addition to the physical laboratory on the lower floor of Building +No. 21, and the house-heating boiler plant with the necessary coal +storage, there are rooms devoted to the storage of heavy supplies, +samples of fuels and oils, and miscellaneous commercial apparatus. One +room is occupied by the ventilating fan and one is used for the +<!--png300--> +<span class = "pagenum">278</span> +<a name = "page278"> </a> +necessary crushers, rolls, sizing screens, etc., required in connection +with the sampling of coal prior to analysis.</p> + +<p> +The Quartermaster’s Department having expressed a wish that tests be +made of the heating value and efficiency of the various fuels offered +that Department, in connection with the heating of military posts +throughout the country, three house-heating boilers were procured which +represent, in a general way, the types and sizes used in a medium-sized +hospital or other similar building, and in smaller residences (Fig. 2, +<a href = "#plate_XVI">Plate XVI</a>). The larger apparatus is a +horizontal return-tubular boiler, 60 in. in diameter, 16 ft. long, and +having fifty-four 4-in. tubes.<a class = "tag" name = "tag14" href = +"#note14">14</a></p> + +<p> +In order to determine whether such a boiler may be operated under +heating conditions without making smoke, when burning various kinds of +coal, it has been installed in accordance with accepted ideas regarding +the prevention of smoke. A fire-brick arch extends over the entire grate +surface and past the bridge wall. A baffle wall has been built in the +combustion chamber, which compels the gases to pass downward and to +divide through two openings before they reach the boiler shell. +Provision has been made for the admission of air at the front of the +furnace, underneath the arch, and at the rear end of the bridge wall, +thus furnishing air both above and below the fire. It is not expected +that all coals can be burned without smoke in this furnace, but it is +desirable to determine under what conditions some kinds of coals may be +burned without objectionable smoke.<a class = "tag" name = "tag15" href += "#note15">15</a></p> + +<p> +For sampling the gases in the smokebox of the horizontal return-tubular +boiler, a special flue-gas sampler was designed, in order to obtain a +composite sample of the gases escaping from the boiler.</p> + +<p> +The other heaters are two cast-iron house-heating boilers. One can +supply 400 sq. ft. of radiation and the other about 4,000 sq. ft. They +were installed primarily for the purpose of testing coals to determine +their relative value when burned for heating purposes. They are piped to +a specially designed separator, and from this to a pressure-reducing +valve. Beyond this valve an orifice allows the steam to escape into the +regular heating mains. This arrangement makes it possible to maintain a +practically constant load on the boilers.</p> + +<p> +<!--png303--> +<span class = "pagenum">279</span> +<a name = "page279"> </a> +There is a fourth boiler, designed and built for testing purposes by the +Quartermaster’s Department. This is a tubular boiler designed on the +lines of a house-heating boiler, but for use as a calorimeter to +determine the relative heat value of different fuels reduced to the +basis of a standard cord of oak wood.</p> + +<p> +A series of research tests on the processes of combustion is being +conducted in Building No. 13, by Mr. Henry Kreisinger. These tests are +being made chiefly in a long combustion chamber (Figs. <a href = +"#fig_16">16</a> and <a href = "#fig_17">17</a>, and Figs. 1 and 2, +<a href = "#plate_XVIII">Plate XVIII</a>), which is fed with coal +from a Murphy mechanical stoker, and discharges the hot gases at the +rear end of the combustion chamber, into the hand-fired Heine boiler. +The walls and roof of this chamber are double; the inner wall is 9 in. +thick, of fire-brick; the outer one is 8 in. thick, and is faced with +red pressed brick. Between the walls of the sides there is a 2-in. air +space, and between them on the roof a 1-in. layer of asbestos paste is +placed. The inner walls and roof have three special slip-joints, to +allow for expansion. The floor is of concrete, protected by a 1½-in. +layer of asbestos board, which in turn is covered by a 3-in. layer of +earth; on top of this earth there is a 4-in. layer of fire-brick (not +shown in the drawings).</p> + +<p class = "illustration"> +<a name = "fig_16"><span class = "smallcaps">Fig. 16.</span></a><br> +<img src = "images/fig16.png" width = "475" height = "213" +alt = "Figure 16"><br> +<span class = "caption"> +CROSS-SECTIONS OF CHAMBER AND OF FURNACE, LONG COMBUSTION +CHAMBER</span></p> + +<p> +Inasmuch as one of the first problems to be attacked will be the +determination of the length of travel and the time required to complete +combustion in a flame in which the lines of stream flow are nearly +parallel, great care was taken to make the inner surfaces of the +<!--png304--> +<span class = "pagenum">280</span> +<a name = "page280"> </a> +tunnel smooth, and all corners and hollows are rounded out in the +direction of travel of the gases.</p> + +<p> +Provision is made, by large peep-holes in the sides, and by smaller +sampling holes in the top, for observing the fuel bed at several points +and also the flame at 5-ft. intervals along the tunnel. Temperatures and +gas samples are taken simultaneously at a number of points through these +holes, so as to determine, if possible, the progress of combustion (Fig. +1, <ins class = "correction" title = "text reads ‘Pate’">Plate</ins> +XVIII).</p> + +<p> +About twenty thermo-couples are embedded in the walls, roof, and floor, +some within 1 in. of the inside edge of the tunnel walls, and some in +the red pressed brick near the outer surface, the object of which is to +procure data on heat conduction through well-built brick walls<a class = +"tag" name = "tag16" href = "#note16">16</a> (Fig. 2, <a href = +"#plate_XVIII">Plate XVIII</a>).</p> + +<!--png301--> +<p class = "illustration"> +<span class = "pagenum">[opp. 278]</span> +<a name = "plate_XVIII"><span class = "smallcaps">Plate +XVIII.</span></a><br> +<img src = "images/plate18a.jpg" width = "500" height = "364" +alt = "Plate XVIII Fig. 1"><br> +<span class = "smallcaps">Fig. 1.—Long Combustion +Chamber.</span><br> +<img src = "images/plate18b.jpg" width = "500" height = "342" +alt = "Plate XVIII Fig. 2"><br> +<span class = "smallcaps">Fig. 2.—Gas Sampling Apparatus, Long +Combustion Chamber.</span></p> + +<p> +In order to minimize the leakage of air through the brickwork, the +furnace and tunnel are kept as nearly as possible at atmospheric +pressure by the combined use of pressure and exhausting fans. +Nevertheless, the leakage is determined periodically as accurately as +possible.</p> + +<p> +At first a number of tests were run to calibrate the apparatus as a +whole, all these preliminary tests being made on cheap, carefully +inspected, uniform screenings from the same seam of the same mine near +Pittsburg. Later tests will be run with other coals of various volatile +contents and various distillation properties.</p> + +<p> +It is anticipated that the progress of the tests may suggest changes in +the construction or operation of this chamber. It is especially +contemplated that the section of the chamber may be narrowed down by +laying sand in the bottom and fire-brick thereon; also that baffle walls +may be built into various portions of it, and that cooling surfaces with +baffling may be introduced. In addition to variations in the tests, due +to changes in construction in the combustion chamber, there will be +variations in the fuels tested. Especial effort will be made to procure +fuels ranging in volatile content from 15 to 27 and to 40%, and those +high in tar and heavy hydro-carbons. It is also proposed to vary the +conditions of testing by burning at high rates, such as at 15, 20, and +30 lb. per ft. of grate surface, and even higher. Records will be kept +of the weight of coal fired and of each firing, of +<!--png306--> +<span class = "pagenum">282</span> +<a name = "page282"> </a> +the weight of ash, etc.; samples of coal and of ash will be taken for +chemical and physical analysis, as well as samples of the gas, and other +essential data. These records will be studied in detail.</p> + +<!--png305--> +<p class = "illustration"> +<span class = "pagenum">[281]</span> +<a name = "page281"> </a> +<a name = "fig_17"><span class = "smallcaps">Fig. 17.</span></a><br> +<a href = "images/fig17.png"> +<img src = "images/thumb17.png" width = "288" height = "146" +alt = "Figure 17 thumbnail"></a><br> +<span class = "caption"> +LONGITUDINAL SECTIONS OF LONG COMBUSTION CHAMBER</span></p> + +<p> +A series of heat-transmission tests undertaken two years ago, is being +continued on the ground floor of Building No. 21, on modified apparatus +reconstructed in the light of the earlier experiments by Mr. W. T. +Ray. The purpose of the tests on this apparatus has been to determine +some of the laws controlling the rate of transmission of heat from a hot +gas to a liquid and <i>vice versa</i>, the two being on the opposite +sides of a metal tube.</p> + +<p> +It appears that four factors determine the rate of heat impartation from +the gas to any small area of the metal<a class = "tag" name = "tag17" +href = "#note17">17</a>:</p> + +<p class = "hanging"> +(1).—The temperature difference between the body of the gas and +the metal;</p> + +<p class = "hanging"> +(2).—The weight of the gas per cubic foot, which is proportional +to the number of molecules in any unit of volume;</p> + +<p class = "hanging"> +(3).—The bodily velocity of the motion of the gas parallel to any +small area under consideration; and (probably),</p> + +<p class = "hanging"> +(4).—The specific heat of the gas at constant pressure.</p> + +<p> +The apparatus consists of an electric resistance furnace containing +coils of nickel wire, a small (interchangeable) multi-tubular boiler, +and a steam-jet apparatus for reducing the air pressure at the exit end, +so as to cause a flow of air through the boiler. A surface condenser was +attached to the boiler’s steam outlet, the condensed steam being weighed +as a check on the feed-water measurements. A number of thermometers and +thermo-couples were used to obtain atmospheric-air temperature, +temperatures of the air entering and leaving the boilers, and feed-water +temperature.</p> + +<p> +The apparatus is now being reconstructed with appliances for measuring +the quantity of air entering the furnace, and an automatic +electric-furnace temperature regulator.</p> + +<p> +Three sizes of boiler have been tested thus far, the dimensions being as +given in Table 4.</p> + +<p> +Each of the three boilers was tested at several temperatures of entering +air, up to 1,500° Fahr., about ten tests being made at each temperature. +It is also the intention to run, on these three boilers, +<!--png309--> +<span class = "pagenum">283</span> +<a name = "page283"> </a> +about eight tests at temperatures of 1,800°, 2,100° and 2,400° Fahr., +respectively. A bulletin on the work already done, together with much +incidental matter, is in course of preparation.<a class = "tag" name = +"tag18" href = "#note18">18</a></p> + +<h5 class = "smallcaps">TABLE 4.—Dimensions of Boilers Nos. 1, 2, +and 3.</h5> + +<table class = "lines"> +<tr class = "lines"> +<th>Items.</th> +<th class = "leftline">Boiler<br> +No. 1.</th> +<th class = "leftline">Boiler<br> +No. 2.</th> +<th class = "leftline">Boiler<br> +No. 3.</th> +</tr> +<tr> +<td><div class = "hanging"> +Distance, outside to outside of boiler heads, in inches</div></td> +<td class = "decimal leftline"> 8.28</td> +<td class = "decimal leftline"> 8.28</td> +<td class = "decimal leftline">16.125</td> +</tr> +<tr> +<td><div class = "hanging"> +Actual outside diameter of flues, in inches</div></td> +<td class = "decimal leftline"> 0.252</td> +<td class = "decimal leftline"> 0.313</td> +<td class = "decimal leftline"> 0.252</td> +</tr> +<tr> +<td><div class = "hanging"> +Actual inside diameter of flues, in inches</div></td> +<td class = "decimal leftline"> 0.175</td> +<td class = "decimal leftline"> 0.230</td> +<td class = "decimal leftline"> 0.175</td> +</tr> +<tr> +<td><div class = "hanging"> +Number of flues (tubes)</div></td> +<td class = "decimal leftline">10</td> +<td class = "decimal leftline">10</td> +<td class = "decimal leftline">10</td> +</tr> +</table> + +<p> +The work on the first three boilers is only a beginning; preparations +are being made to test eight more multi-tubular boilers of various +lengths and tube diameters, under similar conditions. Because of the +experience already obtained, it will be necessary to make only eight +tests at each initial air temperature.</p> + +<p> +When the work on multi-tubular boilers is completed, water-tube boilers +will be taken up, for which a fairly complete outline has been prepared. +This second or water-tube portion of the investigation is really of the +greater scientific and commercial interest, but the multi-tubular +boilers were investigated first because the mathematical treatment is +much simpler.</p> + +<p> +<i>Producer-Gas Tests.</i>—The producer-gas plant at the Pittsburg +testing station is in charge of Mr. Carl D. Smith, and has been +installed for the purpose of testing low-grade fuel, bone coal, roof +coal, mine refuse, and such material as is usually considered of little +value, or even worthless for power purposes. The gas engine, gas +producer, economizer, wet scrubber (Fig. 1, <a href = +"#plate_XIX">Plate XIX</a>), and accessories, are in Building No. +13, and the dry scrubber, gas-holder, and water-cooling apparatus are +immediately outside that building (Fig. 2, <a href = +"#plate_XIX">Plate XIX</a>).</p> + +<!--png307--> +<p class = "illustration"> +<span class = "pagenum">[opp. 282]</span> +<a name = "plate_XIX"><span class = "smallcaps">Plate +XIX.</span></a><br> +<img src = "images/plate19a.jpg" width = "500" height = "396" +alt = "Plate XIX Fig. 1"><br> +<span class = "smallcaps">Fig. 1.—Gas Producer, Economizer, and +Wet Scrubber.</span><br> +<img src = "images/plate19b.jpg" width = "500" height = "343" +alt = "Plate XIX Fig. 2"><br> +<span class = "smallcaps">Fig. 2.—Producer Gas: Dry Scrubber and +Gas Holder.</span></p> + +<p> +At present immense quantities of fuel are left at the mines, in the form +of culm and slack, which, in quality, are much below the average output. +Such fuel is considered of little or no value, chiefly because there is +no apparatus in general use which can burn it to good advantage. The +heat value of this fuel is often from 50 to 75% of that of the fuel +marketed, and if not utilized, represents an +<!--png310--> +<span class = "pagenum">284</span> +<a name = "page284"> </a> +immense waste of natural resources. Large quantities of low-grade fuel +are also left in the mines, simply because present conditions do not +warrant its extraction, and it is left in such a way that it will be +very difficult, if not practically impossible, for future generations to +take out such fuel when it will be at a premium. Again, there are large +deposits of low-grade coal in regions far remote from the sources of the +present fuel supply, but where its successful and economic utilization +would be a boon to the community and a material advantage to the country +at large. The great importance of the successful utilization of +low-grade fuel is obvious. Until within very recent years little had +been accomplished along these lines, and there was little hope of ever +being able to use these fuels successfully.</p> + +<p> +The development of the gas producer for the utilization of ordinary +fuels,<a class = "tag" name = "tag19" href = "#note19">19</a> however, +indicates that the successful utilization of practically all low-grade +fuel is well within the range of possibility. It is notable that, +although all producer-gas tests at the Government testing stations, at +St. Louis and Norfolk, were made in a type of producer<a class = "tag" +name = "tag20" href = "#note20">20</a> designed primarily for a good +grade of anthracite coal, the fuels tested included a wide range of +bituminous coals and lignites, and even peat and bone coal, and that, in +nearly every test, little serious difficulty was encountered in +maintaining satisfactory operating conditions.<a class = "tag" name = +"tag21" href = "#note21">21</a> It is interesting to note that in one +test, a bone coal containing more than 45% of ash was easily handled in +the producer, and that practically full load was maintained for the +regulation test period of 50 hours.<a class = "tag" name = "tag22" href += "#note22">22</a></p> + +<p> +It is not expected that all the fuels tested will prove to be of +immediate commercial value, but it is hoped that much light will be +thrown on this important problem.</p> + +<p> +The equipment for this work consists of a single gas generator, rated at +150 h.p., and a three-cylinder, vertical gas engine of the same +capacity. The producer is a Loomis-Pettibone, down-draft, made by the +Power and Mining Machinery Company, of Cudahy, Wis., and is known as its +“Type C” plant. The gas generator consists of a +<!--png313--> +<span class = "pagenum">285</span> +<a name = "page285"> </a> +cylindrical shell, 6 ft. in diameter, carefully lined with fire-brick, +and having an internal diameter of approximately 4 ft. Near the bottom +of the generator there is a fire-brick grate, on which the fuel bed +rests. The fuel is charged at the top of the producer through a door +(Fig. 1, <a href = "#plate_XX">Plate XX</a>), which may be left +open a considerable time without affecting the operation of the +producer, thus enabling the operator to watch and control the fuel bed +with little inconvenience. As the gas is generated, it passes downward +through the hot fuel bed and through the fire-brick grate. This +down-draft feature “fixes,” or makes into permanent gases, the tarry +vapors which are distilled from bituminous coal when it is first charged +into the producer. A motor-driven exhauster with a capacity of 375 cu. +ft. per min., draws the hot gas from the base of the producer through an +economizer, where the sensible heat of the gas is used to pre-heat the +air and to form the water vapor necessary for the operation of the +producer. The pre-heated air and vapor leave the economizer and enter +the producer through a passageway near the top and above the fuel bed. +From the economizer the gas is drawn through a wet scrubber where it +undergoes a further cooling and is cleansed of dirt and dust. After +passing the wet scrubber, the gas, under a light pressure, is forced, by +the exhauster, through a dry scrubber to a gas-holder with a capacity of +about 1,000 cu. ft.</p> + +<p> +All the fuel used is carefully weighed on scales which are checked from +time to time by standard weights; and, as the fuel is charged into the +producer, a sample is taken for chemical analysis and for the +determination of its calorific power. The water required for the +generation of the vapor is supplied from a small tank carefully +graduated to pounds; this observation is made and recorded every hour. +All the water used in the wet scrubber is measured by passing it through +a piston-type water meter, which is calibrated from time to time to +insure a fair degree of accuracy in the measurement. Provision is made +for observing the pressure and temperature of the gas at various points; +these are observed and recorded every hour.</p> + +<p> +From the holder the gas passes through a large meter to the vertical +three-cylinder Westinghouse engine, which is connected by a belt to a +175-kw., direct-current generator. The load on the generator is measured +by carefully calibrated switch-board instruments, and is regulated by a +specially constructed water rheostat which stands in front of the +building.</p> + +<p> +<!--png314--> +<span class = "pagenum">286</span> +<a name = "page286"> </a> +Careful notes are kept of the engine operation; the gas consumption and +the load on the engine are observed and recorded every 20 min.; the +quantity of jacket water used on the gas engine, and also its +temperature entering and leaving the engine jackets, are recorded every +hour. Indicator cards are taken every 2 hours. The work is continuous, +and each day is divided into three shifts of 8 hours each; the length of +a test, however, is determined very largely by the character and +behavior of the fuel used.</p> + +<p> +A preliminary study of the relative efficiency of the coals found in +different portions of the United States, as producers of illuminating +gas, has been nearly completed under the direction of Mr. Alfred H. +White, and a bulletin setting forth the results is in press.<a class = +"tag" name = "tag23" href = "#note23">23</a></p> + +<p> +<i>Tests of Liquid Fuels.</i>—Tests of liquid fuels in +internal-combustion engines, in charge of Mr. R. M. Strong, are +conducted in the engine-room of Building No. 13.</p> + +<p> +The various liquid hydro-carbon fuels used in internal-combustion +engines for producing power, range from the light refined oils, such as +naphtha, to the crude petroleums, and have a correspondingly wide +variation of physical and chemical properties.</p> + +<p> +The most satisfactory of the liquid fuels for use in internal-combustion +engines, are alcohol and the light refined hydro-carbon oils, such as +gasoline. These fuels, however, are the most expensive in commercial +use, even when consumed with the highest practical efficiency, which, it +is thought, has already been attained, as far as present types of +engines are concerned.</p> + +<p> +At present little is known as to how far many of the very cheap +distillates and crude petroleums can be used as fuel for +internal-combustion engines. It is difficult to use them at all, +regardless of efficiency.</p> + +<p> +Gasoline is comparatively constant in quality, and can be used with +equal efficiency in any gasoline engine of the better grade. There are +many makes of high-grade gasoline engines, tests on any of which may be +taken as representative of the performance and action of gasoline in an +internal-combustion engine, if the conditions under which the tests were +made are clearly stated and are similar.</p> + +<p> +Kerosene varies widely in quality, and requires special devices for its +use, but is a little cheaper than gasoline. It is possible that the +<!--png315--> +<span class = "pagenum">287</span> +<a name = "page287"> </a> +kerosene engine may be developed so as to permit it to take the place of +the smaller stationary and marine gasoline engines. This would mean +considerable saving in fuel cost to the small power user, who now finds +the liquid-fuel internal-combustion engine of commercial advantage. A +number of engines at present on the market use kerosene; some use only +the lighter grades and are at best comparatively less efficient than +gasoline engines. All these engines have to be adjusted to the grade of +oil to be used in order to get the best results.</p> + +<p> +Kerosene engines are of two general types: the external-vaporizer type, +in which the fuel is vaporized and mixed with air before or as it is +taken into the cylinder; and the internal-vaporizer type, in which the +liquid fuel is forced into the cylinder and vaporized by contact with +the hot gases or heated walls of a combustion chamber at the head of the +cylinder. A number of special devices for vaporizing kerosene and the +lighter distillates have been tried and used with some success. Heat is +necessary to vaporize the kerosene as quickly as it is required, and the +degree of heat must be held between the temperature of vaporization and +that at which the oil will be carbonized. The vapor must also be +thoroughly and uniformly mixed with air in order to obtain complete +combustion. As yet, no reliable data on these limiting temperatures for +kerosene and similar oils have been obtained. No investigation has ever +been made of possible methods for preventing the oils from carbonizing +at the higher temperatures, and the properties of explosive mixtures of +oil vapors and air have not been studied. This field of engineering +laboratory research is of vital importance to the solution of the +kerosene-engine problem.</p> + +<p> +Distillates or fuel oils and the crude oils are much the cheapest of the +liquid fuels, and if used efficiently in internal-combustion engines +would be by far the cheapest fuels available in many large +districts.</p> + +<p> +Several engine builders are developing kerosene vaporizers, which are +built as a part of the engine, or are adapted to each different engine, +as required to obtain the best results. Most of these vaporizers use the +heat and the exhaust gases to vaporize the fuel, but they differ greatly +in construction; some are of the retort type, and others are of the +float-feed carburetter type. To what extent the lower-grade fuel oils +can be used with these vaporizers is yet to be determined.</p> + +<p> +<!--png316--> +<span class = "pagenum">288</span> +<a name = "page288"> </a> +There are only a few successful oil engines on the American market. The +most prominent of these represent specific applications of the principal +methods of internal vaporization, and all except one are of the hot-bulb +ignition type. It will probably be found that no one of the 4-stroke +cycle, or 2-stroke cycle, engines is best for all grades of oil, but +rather that each is best for some one grade. The Diesel engine is in a +class by itself, its cycle and method of control being somewhat +different from the others.</p> + +<p> +An investigation of the comparative adaptability of gasoline and alcohol +to use in internal-combustion engines, consisting of more than 2,000 +tests, was made at the temporary fuel-testing plant of the Geological +Survey, at Norfolk, Va., in 1907. A detailed report of these tests is in +preparation.<a class = "tag" name = "tag24" href = "#note24">24</a> A +similar investigation of the comparative adaptability of kerosenes has +been commenced, with a view to obtaining data on their economical use, +leading up to the investigation of the comparative fuel values of the +cheaper distillates and crude petroleum, as before discussed.</p> + +<p> +<i>Washing and Coking Tests.</i>—The investigations relating to +the preparation of low-grade coals, such as those high in ash or +sulphur, by processes that will give them a higher market value or +increase their efficiency in use, are in charge of Mr. A. W. +Belden. They include the washing and coking tests of coals, and the +briquetting of slack and low-grade coal and culm-bank refuse so as to +adapt these fuels for combustion in furnaces, etc.</p> + +<p> +This work has been conducted in the washery and coking plant temporarily +located at Denver, Colo., and in Building No. 32 at the Pittsburg +testing station, where briquetting is in progress. The details of these +tests are set forth in the various bulletins issued by the Geological +Survey.<a class = "tag" name = "tag25" href = "#note25">25</a></p> + +<p> +The washing tests are carried out in the following manner: As the raw +coal is received at the plant, it is shoveled from the railroad cars to +the hopper scale, and weighed. It then passes through the tooth-roll +crusher, where the lumps are broken down to a maximum size of 2½ in. An +apron conveyor delivers the coal to an elevator +<!--png317--> +<span class = "pagenum">289</span> +<a name = "page289"> </a> +which raises it to one of the storage bins. As the coal is being +elevated, an average sample representing the whole shipment is taken. An +analysis is made of this sample of raw coal and float-and-sink tests are +run to determine the size to which it is necessary to crush before +washing, and the percentage of refuse with the best separation. From the +data thus obtained, the washing machines are adjusted so that the +washing test is made with full knowledge of the separations possible +under varying percentages of refuse. The raw coal is drawn from the bin +and delivered to a corrugated-roll disintegrator, where it is crushed to +the size found most suitable, and is then delivered by the raw-coal +elevator to another storage bin. The arrangement of the plant is such +that the coal may be first washed on a Stewart jig, and the refuse then +delivered to and re-washed on a special jig, or the refuse may be +re-crushed and then re-washed.</p> + +<p> +When the coal is to be washed, it drops to the sluice box, where it is +mixed with the water and sluiced to the jigs. In drawing off the washed +coal, or when the uncrushed raw coal is to be drawn from a bin and +crushed for the washing tests, however, a gate just below the coal-flow +regulating gate is thrown in, and the coal falls into a central hopper +instead of into the sluice box. Ordinarily, this gate forms one side of +the vertical chute. The coal in this central hopper is carried by a +chute to the apron conveyor, and thence to the roll disintegrator, or, +in case it is washed coal, to a swing-hammer crusher. It will be noted +that coal, in this manner, can be drawn from a bin at the same time that +coal is being taken from another bin, and sluiced to the jigs for +washing, the two operations not interfering in the least.</p> + +<p> +The washed coal, after being crushed and elevated to the top of the +building, is conveyed by a chute to the coke-oven larry, and is weighed +on the track scale, after which it is charged to the oven. The refuse is +sampled and weighed as it is wheeled to the dump pile, and from this +sample the analysis is made and a float-and-sink test run to determine +the “loss of good coal” in the refuse and to show the efficiency of the +washing test.</p> + +<p> +The coking tests have been conducted in a battery of two beehive ovens, +one 7 ft. high and 12 ft. in diameter, the other, 6¼ ft. high and 12 ft. +in diameter. A standard larry with a capacity of 8 tons, and the +necessary scales for weighing accurately the coal charged and +<!--png318--> +<span class = "pagenum">290</span> +<a name = "page290"> </a> +coke produced, complete the equipment. The coal is usually run through a +roll crusher which breaks it to about ½-in. size, or through a +Pennsylvania hammer crusher. The fineness of the coals put through the +hammer crusher varies somewhat, but the average, taken from a large +number of samples, is as follows: Through ⅛-in. mesh, 100%; over +10-mesh, 31.43%; over 20-mesh, 24.29%; over 40-mesh, 22.86%; over +60-mesh, 10 per cent. The results of the coking tests are set forth in +detail in the various publications issued on this subject.<a class = +"tag" name = "tag26" href = "#note26">26</a></p> + +<p> +Tests of coke produced in the illuminating-gas investigations before +referred to, and a study of commercial coking and by-product plants, are +included in these investigations.</p> + +<p> +<i>Briquetting Investigations.</i>—These investigations are in +charge of Mr. C. L. Wright, and are conducted in Building No. 32, +which is of fire-proof construction, having a steel-skeleton frame work, +reinforced-concrete floors, and 2-in. cement curtain walls, plastered on +expanded-metal laths. In this building two briquetting machines are +installed, one an English machine of the Johnson type, and the other a +German lignite machine of very powerful construction.</p> + +<p> +The investigations include the possibility of making satisfactory +commercial fuels from lignite or low-grade coals which do not stand +shipment well, the benefiting of culm or slack coals which are wasted or +sold at unremunerative prices, and the possibility of improving the +efficiency of good coals. Some of the various forms of commercial +briquettes, American and foreign, are shown in Fig. 2, <a href = +"#plate_XX">Plate XX</a>. After undergoing chemical analysis, the +coal is elevated and fed to a storage bin, whence it is drawn through a +chute to a hopper on the weighing scales. There it is mixed with varying +percentages of different kinds of binding material, and the tests are +conducted so as to ascertain the most suitable binder for each kind of +fuel, which will produce the most durable and weather-proof briquette at +least cost, and the minimum quantity necessary to produce a good, firm +briquette. After weighing, the materials to be tested are run through +the necessary grinding and pulverizing machines and are fed into the +briquetting machines, whence the manufactured briquettes are delivered +for loading or storage. The materials to be used in the German machine +are also dried and cooled again.</p> + +<!--png311--> +<p class = "illustration"> +<span class = "pagenum">[opp. 284]</span> +<a name = "plate_XX"><span class = "smallcaps">Plate XX.</span></a><br> +<img src = "images/plate20a.jpg" width = "500" height = "351" +alt = "Plate XX Fig. 1"><br> +<span class = "smallcaps">Fig. 1.—Charging Floor of Gas +Producer.</span><br> +<img src = "images/plate20b.jpg" width = "500" height = "364" +alt = "Plate XX Fig. 2"><br> +<span class = "smallcaps">Fig. 2.—European and American +Briquettes.</span></p> + +<p> +<!--png321--> +<span class = "pagenum">291</span> +<a name = "page291"> </a> +The briquettes made at this plant are then subjected to physical tests +in order to determine their weathering qualities and their resistance to +abrasion; extraction tests and chemical analyses are also made. +Meanwhile other briquettes from the same lots are subjected to +combustion tests for comparison with the same coal not briquetted. These +tests are made in stationary boilers, in house-heating boilers, on +locomotives, naval vessels, etc., and the results, both of the processes +of manufacture, and of the tests, are published in various bulletins +issued by the Geological Survey.<a class = "tag" name = "tag27" href = +"#note27">27</a></p> + +<p> +The equipment includes storage bins for the raw coal, scales for +weighing, machines for crushing or cracking the pitch, grinders, +crushers, and disintegrators for reducing the coal to the desired +fineness, heating and mixing apparatus, presses and moulds for forming +the briquettes, a Schulz drier, and a cooling apparatus.</p> + +<p> +There is a small experimental hand-briquetting press (Fig. 1, <a href = +"#plate_XXI">Plate XXI</a>) for making preliminary tests of the +briquetting qualities of the various coals and lignites. With this it is +easily possible to vary the pressure, heat, percentage and kind of +binder, so as to determine the best briquetting conditions for each fuel +before subjecting it to large-scale commercial tests in the big +briquetting machines.</p> + +<p> +This hand press will exert pressures up to 50 tons or 100,000 lb. per +sq. in., on a plunger 3 in. in diameter. This plunger enters a mould, +which can be heated by a steam jacket supplied with ordinary saturated +steam at a pressure of 125 lb., and compresses the fuel into a +briquette, 8 in. long, under the conditions of temperature and pressure +desired.</p> + +<p> +The Johnson briquetting machine, which requires 25 h.p. for its +operation, exerts a pressure of about 2,500 lb. per sq. in., and makes +briquettes of rectangular form, 6¾ by 4¼ by 2½ in., and having an +average weight of about 3¾ lb. The capacity of the machine (Fig. 2, <a +href = "#plate_XXI">Plate XXI</a>) is about 3.8 tons of briquettes +per 8-hour day.</p> + +<!--png319--> +<p class = "illustration"> +<span class = "pagenum">[opp. 290]</span> +<a name = "plate_XXI"><span class = "smallcaps">Plate +XXI.</span></a><br> +<img src = "images/plate21a.jpg" width = "264" height = "500" +alt = "Plate XXI Fig. 1"><br> +<span class = "smallcaps">Fig. 1.—Hand Briquetting +Press.</span><br> +<img src = "images/plate21b.jpg" width = "369" height = "500" +alt = "Plate XXI Fig. 2"><br> +<span class = "smallcaps">Fig. 2.—Coal Briquetting +Machine.</span></p> + +<p> +Under the hopper on the scales for the raw material is a square wooden +reciprocal plunger which pushes the fuel into a hole in the floor at a +uniform rate. The pitch is added as uniformly as possible by hand, as +the coal passes this hole. Under this hole a horizontal screw conveyor +carries the fuel and pitch to the disintegrator, in front +<!--png322--> +<span class = "pagenum">292</span> +<a name = "page292"> </a> +of which, in the feeding chute, there is a powerful magnet for picking +out any pieces of iron which might enter the machine and cause +trouble.</p> + +<p> +The ground mixture is elevated from the disintegrator to a point above +the top of the upper mixer of the machine. At the base of this cylinder, +steam can be admitted by several openings to heat the material to any +desired temperature, usually from 180° to 205° Fahr. There, a plunger, +making 17 strokes per min., compresses two briquettes at each +stroke.</p> + +<p> +The German lignite-briquetting machine (Figs. <a href = "#fig_18">18</a> +and <a href = "#fig_19">19</a>) was made by the Maschinenfabrik +Buckau Actien-Gesellschaft, Magdeburg, Germany. Lignite from the storage +room on the third floor of the building is fed into one end of a Schulz +tubular drier (Fig. 1, <a href = "#plate_XXII">Plate XXII</a>), +which is similar to a multi-tubular boiler set at a slight angle from +the horizontal, and slowly revolved by worm and wheel gearing, the +lignite passing through the tubes and the steam being within the boiler. +From this drier the lignite passes through a sorting sieve and crushing +rolls to a cooling apparatus, which consists of four horizontal circular +plates, about 13 ft. in diameter, over which the dried material is moved +by rakes. After cooling, the material is carried by a long, worm +conveyor to a large hopper over the briquette press, and by a feeding +box to the press (Fig. 2, <a href = +"#plate_XXII">Plate XXII</a>).</p> + +<!--png325--> +<p class = "illustration"> +<span class = "pagenum">[opp. 294]</span> +<a name = "plate_XXII"><span class = "smallcaps">Plate +XXII.</span></a><br> +<img src = "images/plate22a.jpg" width = "500" height = "398" +alt = "Plate XXII Fig. 1"><br> +<span class = "smallcaps">Fig. 1.—Dryer for Lignite Briquetting +Press.</span><br> +<img src = "images/plate22b.jpg" width = "500" height = "384" +alt = "Plate XXII Fig. 2"><br> +<span class = "smallcaps">Fig. 2.—Lignite Briquetting +Machine.</span></p> + +<p> +The press, which is of the open-mould type, consists of a ram and die +plates, the latter being set so as to make a tube which gradually tapers +toward the delivery end of the machine. The briquettes have a +cross-section similar to an ellipse with the ends slightly cut off; they +are about 1¼ in. thick and average about 1 lb. in weight (Fig. 2, <a +href = "#plate_XX">Plate XX</a>). The press is operated by a direct +connection with a steam engine of 150 h.p., the base of which is +continuous with that of the press. The exhaust steam from the engine is +used to heat the driver.</p> + +<p> +The plunger makes from 80 to 100 strokes per min., the pressure exerted +ranging from 14,000 to 28,000 lb. per sq. in., the capacity of the +machine being 1 briquette per stroke, or from 2½ to 3 tons of completed +briquettes per hour. It is expected that no binder will be needed for +practically all the brown lignite briquetted by this machine, thus +reducing the cost as compared with the briquetting of coals, which +require from 5 to 7% of water-gas, pitch binder costing more than 50 +cents per ton of manufactured briquettes.</p> + +<!--png323--> +<p class = "illustration"> +<span class = "pagenum">[293]</span> +<a name = "page293"> </a> +<a name = "fig_18"><span class = "smallcaps">Fig. 18.</span></a><br> +<img src = "images/fig18.png" width = "441" height = "438" +alt = "LONGITUDINAL-SECTION OF LIGNITE-BRIQUETTING PLANT"></p> + + +<p class = "illustration"> +<a name = "fig_19"><span class = "smallcaps">Fig. 19.</span></a><br> +<img src = "images/fig19.png" width = "433" height = "431" +alt = "CROSS-SECTION OF LIGNITE-BRIQUETTING PLANT"></p> + +<p> +<!--png324--> +<span class = "pagenum">294</span> +<a name = "page294"> </a> +<i>Peat Investigations.</i>—Investigations into the distribution, +production, origin, nature, and uses of peat are being conducted by Mr. +C. A. Davis, and include co-operative arrangements with State +Geological Surveys and the Geologic Branch of the U. S. Geological +Survey. These organizations conduct surveys which include the mapping of +the peat deposits in the field, the determination of their extent and +limitations, the sampling of peat from various depths, and the +transmittal of samples to the Pittsburg laboratories for analysis and +test.<a class = "tag" name = "tag28" href = "#note28">28</a></p> + +<p> +This work is co-ordinated in such a manner as to result in uniform +methods of procedure in studying the peat deposits of the United States. +The samples of peat are subjected to microscopic examination, in order +to determine their origin and age, and to chemical and physical tests at +the laboratories in Pittsburg, so as to ascertain the chemical +composition and calorific value, the resistance to compressive strains, +the ash and moisture content, drying properties, resistance to abrasion, +etc. Occasionally, large quantities of peat are disintegrated and +machined, and portions, after drying for different periods, are +subjected to combustion tests in steam boilers and to tests in the gas +producer, to ascertain their efficiency as power producers.</p> + +<p> +<i>Results.</i>—The full value of such investigations as have been +described in the preceding pages cannot be realized for many years; but, +even within the four years during which this work has been under way, +certain investigations have led to important results, some of which may +be briefly mentioned:</p> + +<p> +The chemical and calorific determinations of coals purchased for the use +of the Government have resulted in the delivery of a better grade of +fuel without corresponding increase in cost, and, consequently, in +saving to the Government. Under this system, of purchasing its coal +under specifications and testing, the Government is getting more nearly +what it pays for and is paying for what it gets. These investigations, +by suggesting changes in equipment and methods, are also indicating the +practicability of the purchase of cheaper fuels, such as bituminous coal +and the smaller sizes of pea, buckwheat, etc., instead of the more +expensive sizes of anthracite, with a corresponding saving in cost. The +Government’s fuel bill now aggregates about $10,000,000 yearly.</p> + +<p> +<!--png327--> +<span class = "pagenum">295</span> +<a name = "page295"> </a> +The making and assembling of chemical analyses and calorific +determinations (checked by other tests) of carefully selected samples of +coals from nearly 1,000 different localities, in the different coal +fields of the United States, with the additions, from time to time, of +samples representing parts of coal fields or newly opened beds of coal +in the same field, furnish invaluable sources of accurate information, +not only for use of the Government, but also for the general public. Of +the above-mentioned localities, 501 were in the public-land States and +427 in the Central, Eastern, and Southern States.</p> + +<p> +The chemical <ins class = "correction" title = +"text reads ‘anaylses’">analyses</ins> +of the coals found throughout the United +States have been made with such uniformity of method, both as to +collection of samples and analytical procedure, as to yield results +strictly comparable for coals from all parts of the country, and furnish +complete information, as a basis for future purchases and use by the +Government and by the general public, of all types of American +coals.</p> + +<p> +Other researches have resulted in the acquirement of valuable +information regarding the distribution of temperature in the fuel bed of +gas producers and furnaces, showing a range of from 400° to 1,300° +cent., and have thus furnished data indicating specific difficulties to +be overcome in gas-producer improvements for greater fuel +efficiency.</p> + +<p> +The recent studies of the volatile matter in coal, and its relation to +the operation of coke ovens and other forms of combustion, have +demonstrated that as much as one-third of this matter is inert and +non-combustible, a fact which may have a direct bearing on smoke +prevention by explaining its cause and indicating means for its +abatement.</p> + +<p> +Experiments in the storage of coal have proven that oxygen is absorbed +during exposure to air, thereby causing, in some cases, a deterioration +in heating value, and indicating that, for certain coals, in case they +are to be stored a long time for naval and other purposes, storage under +water is advisable.</p> + +<p> +The tests of different coals under steam boilers have shown the +possibility of increasing the general efficiency of hand-fired steam +boilers from 10 to 15% over ordinary results. If this saving could be +made in the great number of hand-fired boilers now being operated in all +parts of the United States, it would result in large saving in the fuel +bill of the country. Experiments which have been made with +residence-heating boilers justify the belief that it will be possible +<!--png328--> +<span class = "pagenum">296</span> +<a name = "page296"> </a> +to perfect such types of boilers as may economically give a smokeless +operation. The tests under steam boilers furnish specific information as +to the most efficient method of utilizing each of a number of different +types of coal in Government buildings and power plants in different +parts of the country.</p> + +<p> +The tests in the gas producer have shown that many fuels of such low +grade as to be practically valueless for steam-furnace purposes, +including slack coal, bone coal, and lignite, may be economically +converted into producer gas, and may thus generate sufficient power to +render them of high commercial value.</p> + +<p> +Practically every shipment out of several hundred tested in the gas +producers, including coals as high in ash content as 45%, and lignites +and peats high in moisture, has been successfully converted into +producer gas which has been used in operating gas engines. It has been +estimated that on an average there was developed from each coal tested +in the gas-producer plant two and one-half times the power developed +when used in the ordinary steam-boiler plant, and that such relative +efficiencies will probably hold good for the average plant of moderate +power capacity, though this ratio may be greatly reduced in large steam +plants of the most modern type. It was found that the low-grade lignites +of North Dakota developed as much power, when converted into producer +gas, as did the best West Virginia bituminous coals when utilized under +the steam boiler; and, in this way, lignite beds underlying from +20,000,000 to 30,000,000 acres of public lands, supposed to have little +or no commercial value, are shown to have a large value for power +development.</p> + +<p> +The tests made with reference to the manufacture and combustion of +briquetted coal have demonstrated conclusively that by this means many +low-grade bituminous coals and lignites may have their commercial value +increased to an extent which more than covers the increased cost of +making; and these tests have also shown that bituminous coals of the +higher grades may be burned in locomotives with greatly increased +efficiency and capacity and with less smoke than the same coal not +briquetted. These tests have shown that, with the same fuel consumption +of briquettes as of raw coal, the same locomotive can very materially +increase its hauling capacity and thus reduce the cost of +transportation.</p> + +<p> +The investigations into smoke abatement have indicated clearly +<!--png329--> +<span class = "pagenum">297</span> +<a name = "page297"> </a> +that each type of coal may be burned practically without smoke in some +type of furnace or with some arrangement of mechanical stoker, draft, +etc. The elimination of smoke means more complete combustion of the +fuel, and consequently less waste and higher efficiency.</p> + +<p> +The investigations into the waste of coal in mining have shown the +enormous extent of this waste, aggregating probably from 300,000,000 to +400,000,000 tons yearly, of which at least one-half might be saved. It +is being demonstrated that the low-grade coals, high in sulphur and ash, +now left underground, can be used economically in the gas producer for +power and light, and, therefore, should be mined at the same time that +the high-grade coal is being removed. Moreover, attention is now being +called to the practicability of a further large reduction of waste +through more efficient mining methods.</p> + +<p> +The washing tests have demonstrated the fact that many coals, too high +in ash and sulphur for economic use under the steam boiler or for +coking, may be rendered of commercial value by proper treatment in the +washery. The coking tests have also demonstrated that, by proper methods +of preparation for and manipulation in the beehive oven, many coals +which were not supposed to be of economic value for coking purposes, may +be rendered so by prior washing and proper treatment. Of more than 100 +coals tested during 1906 from the Mississippi Valley and the Eastern +States, most of which coals were regarded as non-coking, all except 6 +were found, by careful manipulation, to make fairly good coke for +foundry and other metallurgical purposes. Of 52 coals from the Rocky +Mountain region, all but 3 produced good coke under proper treatment, +though a number of these had been considered non-coking coals.</p> + +<p> +Investigations into the relative efficiency of gasoline and denatured +alcohol as power producers, undertaken in connection with work for the +Navy Department, have demonstrated that with proper manipulation of the +carburetters, igniters, degree of compression, etc., denatured alcohol +has the same power-producing value, gallon for gallon, as gasoline. This +is a most interesting development, in view of the fact that the heat +value of a gallon of alcohol is only a little more than 0.6 that of a +gallon of gasoline. To secure these results, compressions of from 150 to +180 lb. per sq. in. were used, these pressures involving an increase in +weight of engine. Although the engine especially +<!--png330--> +<span class = "pagenum">298</span> +<a name = "page298"> </a> +designed for alcohol will be heavier than a gasoline engine of the same +size, it will have a sufficiently greater power capacity so that the +weight per horse-power need not be greater.</p> + +<p> +Several hundred tons of peat have been tested to determine methods of +drying, compressing into briquettes, and utilization for power +production in the gas producer. In connection with these peat +investigations, a reconnoissance survey has been made of the peat +deposits of the Atlantic Coast. Samples have been obtained by boring to +different depths in many widely distributed peat-bogs, and these samples +have been analyzed and tested in order to determine their origin, +nature, and fuel value.</p> + +<p> +The extent and number of tests from which these results have been +derived will be appreciated from the fact that, in three years, nearly +15,000 tests were made, in each of which large quantities of fuel were +consumed. These tests involved nearly 1,250,000 physical observations +and 67,080 chemical determinations, made with a view to analyze the +results of the tests and to indicate any necessary changes in the +methods as they progressed. For coking, cupola, and washing, 596 tests, +of which nearly 300 involved the use of nearly 1,000 tons of coal, have +been made at Denver. For briquetting, 312 tests have been made. +Briquettes have been used in combustion tests in which 250 tons of +briquetted coal were consumed in battleship tests, 210 tons in +torpedo-boat tests, 320 tons in locomotive tests on three railway +systems, and 70 tons were consumed under stationary steam boilers. Of +producer gas tests, 175 have been made, of which 7 were long-time runs +of a week or more in duration, consuming in all 105 tons of coal. There +have been 300 house-heating boiler tests and 575 steam-boiler tests; +also, 83 railway-locomotive and 23 naval-vessel tests have been made on +run-of-mine coal in comparison with briquetted coal; also, 125 tests +have been made in connection with heat-transmission experiments, and +2,254 gasoline- and alcohol-engine tests. Nearly 10,000 samples of coal +were taken for analysis, of which 3,000 were from public-land States. +Nearly 5,000 inspection samples, of coal purchased by the Government for +its use, have been taken and tested.</p> + +<p> +The results of the tests made in the course of these investigations, as +summarized, have been published in twelve separate Bulletins, three of +which, Nos. 261, 290, and 332, set forth in detail the operations of the +fuel-testing plant for 1904, 1905, and 1906. Professional +<!--png331--> +<span class = "pagenum">299</span> +<a name = "page299"> </a> +Paper No. 48, in three volumes, describes in greater detail each stage +of the operations for 1904 and 1905.</p> + +<p> +Separate Bulletins, descriptive of the methods and results of the work +in detail, have been published, as follows: No. 323, Experimental work +conducted in the chemical laboratory; No. 325, A study of four hundred +steaming tests; No. 334, Burning of coal without smoke in boiler plants; +No. 336, Washing and coking tests of coal, and cupola tests of coke; No. +339, Purchase of coal under specifications on basis of heating value; +No. 343, Binders for coal briquettes; No. 362, Mine sampling and +chemical analyses of coals in 1907; No. 363, Comparative tests of +run-of-mine and briquetted coal on locomotives, including torpedo-boat +tests, and some foreign specifications for briquetted fuel; No. 366, +Tests of coal and briquettes as fuel for house-heating boilers; No. 367, +Significance of drafts in steam-boiler practice; No. 368, Coking and +washing tests of coal at Denver; No. 373, Smokeless combustion of coal +in boiler plants, with a chapter on central heating plants; No. 378, +Results of purchasing coal under Government specifications; No. 382, The +effect of oxygen in coal; and, No. 385, Briquetting tests at +Norfolk, Va.</p> + + +<!--png332--> +<span class = "pagenum">300</span> +<a name = "page300"> </a> +<h4 class = "chapter">DISCUSSION</h4> + +<hr class = "tiny"> + +<p class = "space"> +<span class = "sidenote"><a name = "disc_allen">Mr.<br> +Allen.</a></span> +<span class = "smallcaps">Kenneth Allen, M. Am. Soc. C. +E.</span>—The speaker would like to know whether anything has been +done in the United States toward utilizing marsh mud for fuel.</p> + +<p> +In an address by Mr. Edward Atkinson, before the New England Water Works +Association, in 1904, on the subject of “Bog Fuel,” he referred to its +extensive use in Sweden and elsewhere, and intimated that there was a +wide field for its use in America.</p> + +<p> +The percentage of combustible material in the mud of ordinary marsh +lands is very considerable, and there are enormous deposits readily +available; but it is hardly probable that its calorific value is +sufficiently high to render its general use at this time profitable.</p> + +<p> +As an example of the amount of organic matter which may remain stored in +these muds for many years, the speaker would mention a sample taken from +the bottom of a trench, which he had analyzed a few years ago. Although +taken from a depth of about 15 ft., much of the vegetable fiber remained +intact. The material proved to be 70¾% volatile.</p> + +<p> +Possibly before the existing available coal deposits are exhausted, the +exploitation of meadow muds for fuel may become profitable.</p> + +<p class = "space"> +<span class = "sidenote"><a name = "disc_kreisinger">Mr.<br> +Kreisinger.</a></span> +<span class = "smallcaps">Henry Kreisinger, Esq.</span><a class = "tag" +name = "tag29" href = "#note29">29</a> (by letter).—Mr. Wilson +gives a brief description of a long furnace and an outline of the +research work which is being done in it. It may be well to discuss +somewhat more fully the proposed investigations and point out the +practical value of the findings to which they may lead.</p> + +<p> +In general, the object is to study the process of combustion of coal. +When soft coal is burned in any furnace, part of the combustible is +driven off shortly after charging, and has to be burned in the space +between the fuel bed and the exit of the gases, which is called the +combustion space. There is enough evidence to show that, with a constant +air supply, the completeness of the combustion of the volatile +combustible depends on the length of time the latter stays within the +combustion space; but, with a constant rate of charging the coal, this +length of time depends directly on the extent of the combustion space. +Thus, if the volume of the volatile combustible evolved per second and +the admixed air is 40 cu. ft., and the extent of the combustion space is +80 cu. ft., the average time the gas will stay within the latter is 2 +sec.; if the combustion space is 20 cu. ft., the average time the +mixture can stay in this space is only ½ sec., and its combustion will +be less complete than in the first case. Thus it is seen that the extent +of the combustion space of a furnace is an important factor in the +economic combustion of volatile coals. The specific object of the +<!--png333--> +<span class = "pagenum">301</span> +<a name = "page301"> </a> +investigations, thus far planned, is to determine the extent of the +combustion space required to attain practically complete combustion when +a given quantity of a given coal is burned under definite conditions. +With this object in view, the furnace has been provided with a +combustion space large enough for the highest volatile coals and for the +highest customary rate of combustion. To illustrate the application of +the data which will be obtained by these experiments, the following +queries are given:</p> + +<p> +Suppose it is required to design a furnace which will burn coal from a +certain Illinois mine at the rate of 1,000 lb. per hour, with a +resulting temperature of not less than 2,800° Fahr. How large a +combustion space is required to burn, with practical completeness, the +volatile combustible? What completeness of combustion can be attained, +if the combustion space is only three-fourths of the required extent? In +the present state of the knowledge of the process of combustion of coal, +these queries cannot be answered definitely. In the literature on +combustion one may find statements that the gases must be completely +burned before leaving the furnace or before they strike the cooling +surfaces of the boiler; but there is no definite information available +as to how long the gases must be kept in the furnace or how large the +combustion space must be in order to obtain practically complete +combustion. It is strange that so little is known of such an old art as +the combustion of coal.</p> + +<p> +The research work under consideration is fundamentally a problem in +physical chemistry, and, for that reason, has been assigned to a +committee consisting of the writer as Engineer, Dr. J. C. W. +Frazer, Chemist, and Dr. J. K. Clement, Physicist. The outcome of +the investigation may prove of extreme interest to mechanical and fuel +engineers, and to all who have anything to do with the burning of coal +or the construction of furnaces. In the experiments thus far planned the +following factors will be considered:</p> + +<p> +<i>Effect of the Nature of Coal on the Extent of Combustion Space +Required.</i>—The steaming coals mined in different localities +evolve different volumes of volatile combustible, even when burned at +the same rate. The coal which analyzes 45% of volatile matter evolves a +much greater volume of gases and tar vapors than that analyzing only 15 +per cent. These evolved gases and tar vapors must be burned in the +space. Consequently, a furnace burning high volatile coal must have a +much larger combustion space than that burning coal low in volatile +combustible.</p> + +<p> +There is enough evidence to show that the extent of combustion space +required to burn the volatile combustible depends, not only on the +volume of the combustible mixture, but also on the chemical composition +of the volatile combustible. Thus the volatile combustible of +<!--png334--> +<span class = "pagenum">302</span> +<a name = "page302"> </a> +low volatile coal, when mixed with an equal volume of air, may require 1 +sec. in the combustion space to burn practically to completeness, while +it may require 2 sec. to burn the same volume of the volatile +combustible of high volatile coal with the same completeness; so that +the extent of the combustion space required to burn various kinds of +coal may not be directly proportional to the volatile matter of the +coal.</p> + +<p> +<i>Effect of the Rate of Combustion on the Extent of Combustion Space +Required.</i>—With the same coal, the volume of the volatile +combustible distilled from the fuel bed per unit of time varies as the +rate of combustion. Thus, when this rate is double that of the standard, +the volume of gases and tar vapors driven from the fuel is about +doubled. To this increased volume of volatile combustible, about double +the volume of air must be added, and, if the mixture is to be kept the +same length of time within the combustion space, the latter should be +about twice as large as for the standard rate of combustion. Thus the +combustion space required for complete combustion varies, not only with +the nature of the coal, but also with the rate of firing the fuel, +which, of course, is self-evident.</p> + +<p> +<i>Effect of Air Supply on the Extent of Combustion Space +Required.</i>—Another factor which influences the extent of the +combustion space is the quantity of air mixed with the volatile +combustible. Perhaps, within certain limits, the combustion space may be +decreased when the supply of air is increased. However, any statement at +present is only speculation; the facts must be determined +experimentally. One fact is known, namely, that, in order to obtain +higher temperatures of the products of combustion, the air supply must +be decreased.</p> + +<p> +<i>Effect of Rate of Heating of Coal on the Extent of Combustion Space +Required.</i>—There is still another factor, a very important one, +which, with a given coal and any given air supply, will influence the +extent of the combustion space. This factor is the rate of heating of +the coal when feeding it into the furnace. The so-called “proximate” +analysis of coal is indeed only very approximate. When the analysis +shows, say, 40% of volatile matter and 45% of fixed carbon, it does not +mean that the coal is actually composed of so much volatile matter and +so much fixed carbon; it simply means that, under a certain rate of +heating attained by certain standard laboratory conditions, 40% of the +coal has been driven off as “volatile matter.” If the rate or method of +heating were different, the amount of volatile matter driven off would +also be different. Chemists state that it is difficult to obtain +accurate checks on “proximate” analysis. To illustrate this factor, +further reference may be made to the operation of the up-draft +bituminous gas producers. In the generator of such producers the tar +vapors leave the freshly fired fuel, pass through the wet scrubber, and +are finally separated by the tar extractor as a black, pasty substance +in a semi-liquid state. If this tar is subjected to the standard +proximate +<!--png335--> +<span class = "pagenum">303</span> +<a name = "page303"> </a> +analysis, it will be shown that from 40 to 50% of it is fixed carbon, +although it left the gas generator as volatile matter. It is desired to +emphasize the fact that different rates of heating of high volatile +coals will not only drive off different percentages of volatile matter, +but that the latter itself varies greatly in chemical composition and +physical properties as regards inflammability and rapidity of +combustion. Thus it may be said that the extent of the combustion space +required for the complete oxidation of the volatile combustible depends +on the method of charging the fuel, that is, on how rapidly the fresh +fuel is heated. If this factor is given proper consideration, it may be +possible to reduce very materially the necessary space required for +complete combustion.</p> + +<p> +<i>The Effect of the Rate of Mixing the Volatile Combustible and Air on +the Extent of the Combustion Space.</i>—When studying the effects +discussed in the preceding paragraphs, the rate of mixing the volatile +combustible with the supply of air must be as constant as practicable. +At first, tests will be made with no special mixing devices, the mixing +will be accomplished entirely by the streams of air entering the furnace +at the stoker, and by natural diffusion. Although there appears to be +violent stirring of the gases above the fuel bed, the mixture of the +gases does not become homogeneous until they are about 10 or 15 ft. from +the stoker. The mixing caused by the air currents forced into the +furnace at the stoker is very distinct, and can be readily observed +through the peep-hole in the side wall of the Heine boiler, opposite the +long combustion chamber. This mixing is shown in <a href = +"#fig_20">Fig. 20</a>. <i>A</i> is a current of air forced from the +ash-pit directly upward through the fuel bed; <i>B</i> and <i>B</i> are +streams of air forced above the fuel bed through numerous small openings +at the furnace side of each hopper. Those currents cause the gases to +flow out of the furnace in two spirals, as shown in <a href = +"#fig_20">Fig. 20</a>. The velocity of rotation on the outside of +the two spirals appears to be about 10 ft. per sec., when the rate of +combustion is about 750 lb. of coal per hour. It is reasonable to expect +that when the rate of mixing is increased by building piers and other +mixing structures immediately back of the grate, the completeness of the +combustion will be effected in less time, and a smaller combustion space +will be required. Thus, the mixing structures may be an important factor +in the extent of the required combustion space.</p> + +<p class = "illustration"> +<a name = "fig_20"><span class = "smallcaps">Fig. 20.</span></a><br> +<img src = "images/fig20.png" width = "314" height = "291" +alt = "Figure 20"><br> +<span class = "caption"> +SECTION THROUGH STOKER<br> +SHOWING MIXING OF GASES<br> +CAUSED BY CURRENTS OF AIR</span></p> + +<p> +To sum up, it can be said that the extent of the space required to +obtain a combustion which can be considered complete for all practical +purposes, depends on the following factors:</p> + +<p class = "hanging"> +(<i>a</i>).—Nature of coal,</p> + +<p class = "hanging"> +(<i>b</i>).—Rate of combustion,</p> + +<p class = "hanging"> +(<i>c</i>).—Supply of air,</p> + +<p class = "hanging"> +(<i>d</i>).—Rate of heating fuel,</p> + +<p class = "hanging"> +(<i>e</i>).—Rate of mixing volatile combustible and air.</p> + +<p> +<!--png336--> +<span class = "pagenum">304</span> +<a name = "page304"> </a> +Just how much the extent of the combustion space required will be +influenced by these factors is the object of the experiments under +discussion.</p> + +<p> +<i>The Scope of the Experiments.</i>—With this object in view, as +explained in the preceding paragraphs, the following series of +experiments are planned:</p> + +<p> +Six or eight typical coals are to be selected, each representing a +certain group of nearly the same chemical composition. Each series will +consist of several sets of tests, each set being run with all the +conditions constant except the one, the effect of which on the size of +the combustion space is to be investigated. Thus a set of four or five +tests will be made, varying in rate of combustion from 20 to 80 lb. of +coal per square foot of grate per hour, keeping the supply of air per +pound of combustible and the rate of heating constant. This set will +show the effect of the rate of combustion of the coal on the extent of +space required to obtain combustion which is practically complete. Other +variables, such as composition of coal, supply of air, and rate of +heating, remain constant.</p> + +<p> +<!--png337--> +<span class = "pagenum">305</span> +<a name = "page305"> </a> +Another set of four or five tests will be made with the same coal and at +the same rate of combustion, but the air supply will be different for +each test. This set of tests will be repeated for two or three different +rates of combustion. Thus each of these sets will give the effect of the +air supply on the extent of combustion space when the coal and rate of +combustion remain constant.</p> + +<p> +Still another set of tests should be made in which the time of heating +the coal when feeding it into the furnace will vary from 3 to 30 min. In +each of the tests of this set, the rate of combustion and the air supply +will be kept constant, and the set will be repeated for two or three +rates of combustion and two or three supplies of air. Each of these sets +of tests will give the effect of the rate of heating of fresh fuel on +the extent of combustion space required to burn the distilled volatile +combustible. These sets of experiments will require a modification in +the stoker mechanism, and, on that account, may be put off until all the +other tests on the other selected typical coals are completed. As the +investigation proceeds, enough may be learned so that the number of +tests in each series may be gradually reduced. After all the desirable +tests are made with the furnace as it stands, several kinds of mixing +structures will be built successively back of the stoker and tried, one +kind at a time, with a set of representative tests. Thus the +effectiveness of such mixing structures will be determined.</p> + +<p> +<i>Determining the Completeness of Combustion.</i>—The +completeness of combustion in the successive cross-sections of the +stream of gases is determined mainly by the chemical analysis of samples +of gases collected through the openings at these respective +cross-sections. The first of these cross-sections at which gas samples +are collected, passes through the middle of the bridge wall; the others +are placed at intervals of 5 ft. through the entire length of the +furnace. Measurements of the temperature of the gases, and direct +observations of the length and color of the flames and of any visible +smoke will be also made through the side peep-holes. These direct +observations, together with the gas analysis, will furnish enough data +to determine the length of travel of the combustible mixture to reach +practically complete combustion.</p> + +<p> +In other words, these observations will determine the extent of the +combustion space for various kinds of coal when burned under certain +given conditions. Direct observations and the analysis of gases at +sections nearer the stoker than that at which the combustion is +practically complete, will show how the process of combustion approaches +its completion. This information will be of extreme value in determining +the effect of shortening the combustion space on the loss of heat due to +incomplete combustion.</p> + +<p> +<i>Method of Collecting Gas Samples.</i>—The collection of gas +samples is a difficult problem in itself, when one considers that the +temperature +<!--png338--> +<span class = "pagenum">306</span> +<a name = "page306"> </a> +of the gases, as they are in the furnace, ranges from 2,400° to 3,200° +Fahr.; consequently, the samples must be collected with water-cooled +tubes. Thus far, about 25 preliminary tests have been made. These tests +show that the composition of the gases at the cross-sections near the +stoker is not uniform, and that more than one sample must be taken from +each cross-section. It was decided to take 9 samples from the +cross-section immediately back of the stoker, and reduce the number in +the sections following, according to the uniformity of the gas +composition. Thus, about 35 simultaneous gas samples must be taken for +each test. The samples will be subjected, not only to the usual +determination of CO<sub>2</sub>, O<sub>2</sub> and CO, but to a complete +analysis. It is also realized that some of the carbon-hydrogen compounds +which, at the furnace temperature, exist as heavy gases, are condensed +to liquids and solids when cooled in the sampling tubes, where they +settle and tend to clog it. To neglect the presence of this form of the +combustible would introduce considerable error in the determination of +the completeness of combustion at any of the cross-sections. Therefore, +special water-cooled sampling tubes are constructed and equipped with +filters which separate the liquid and solid combustible from the gases. +The contents of these filters are then also subjected to complete +analysis. To obtain quantitative data, a measured quantity of gases must +be drawn through these filtering sampling tubes.</p> + +<p> +<i>The Measuring of Temperatures.</i>—At present the only possible +known method of measuring the temperature of the furnace gases is by +optical and radiation pyrometers. Platinum thermo-couples are soon +destroyed by the corrosive action of the hot gases. The pyrometers used +at present are the Wanner optical pyrometer and the Fery radiation +pyrometer.</p> + +<p> +<i>The Flow of Heat Through Furnace Walls.</i>—An interesting side +investigation has developed, in the study of the loss of heat through +the furnace walls. In the description of this experimental furnace it +has been said that the side walls contained a 2-in. air space, which, in +the roof, was replaced with a 1-in. layer of asbestos. To determine the +relative resistance to heat flow of the air space and the asbestos +layer, 20 thermo-couples were embedded, in groups of four, to different +depths at three places in the side wall and at two places in the roof. +In the side wall, one of the thermo-couples of each group was placed in +the inner wall near the furnace surface; the second thermo-couple was +placed in the same wall, but near the surface facing the air space; the +third thermo-couple was placed in the outer wall near the inner surface; +and the fourth was placed near the outer surface in the outer wall. In +the roof the second and third thermo-couples were placed in the brick +near the surface on each side of the asbestos layer. These +thermo-couples have shown that the temperature drop across the 2-in. air +space was much less than that across the 1-in. layer of asbestos; +<!--png339--> +<span class = "pagenum">307</span> +<a name = "page307"> </a> +in fact, that it was considerably less than the temperature drop through +the same thickness of the brick wall.</p> + +<p> +The results obtained prove that, as far as heat insulation is concerned, +air spaces in furnace walls are undesirable. The heat is not conducted +through the air, but leaps across the space by radiation. In furnace +construction a solid wall is a better heat insulator than one of the +same total thickness containing an air space. If it is necessary to +build a furnace wall in two parts on account of unequal expansion, the +space between the two walls should be filled with some solid, cheap, +non-conducting materials, such as ash, sand, or crushed brick. A more +detailed account of these experiments may be found in a Bulletin of the +U. S. Geological Survey entitled “The Flow of Heat Through Furnace +Walls.”</p> + +<p class = "space"> +<span class = "sidenote"><a name = "disc_snelling">Mr.<br> +Snelling.</a></span> +<span class = "smallcaps">Walter O. Snelling, Esq.</span><a class = +"tag" name = "tag30" href = "#note30">30</a> (by letter).—The work +of the United States Testing Station at Pittsburg has been set forth so +fully by Mr. Wilson that a further statement as to the results achieved +may seem like repetition. It would be most unlikely, however, that +studies of such variety should possess no other value than along the +direct lines being investigated. In the case of the Mine Accidents +Division, at least, it is certain that the indirect benefits of some of +the studies have been far-reaching, and are now proving of value in +lines far removed from those which were the primary object of the +investigation. They are developing facts which will be of great value to +all engineers or contractors engaged in tunneling or quarrying. As the +writer’s experience has been solely in connection with the chemical +examination of explosives, he will confine his discussion to this +phase.</p> + +<p> +In studying the properties of various explosives, and in testing work to +separate those in which the danger of igniting explosive mixtures of +coal dust and air, or of fire-damp and air, is greatest, from those in +which this danger is least, much information has been collected. Mr. +Wilson has described many of the tests, and it can be readily seen that +in carrying out these and other tests on each of the explosives +submitted, a great many facts relating to the properties of explosive +compounds have been obtained, which were soon found to be of decided +value in directions other than the simple differentiation of explosives +which are safe from those which are unsafe in the presence of explosive +mixtures of fire-damp or coal dust.</p> + +<p> +The factors which determine the suitability of an explosive for work in +material of any particular physical characteristics depend on the +relationship of such properties as percussive force (or the initial blow +produced by the products of the decomposition of the explosive at the +moment of explosion), and the heaving force (or the continued pressure +produced by the products of the decomposition, after the +<!--png340--> +<span class = "pagenum">308</span> +<a name = "page308"> </a> +initial blow at the instant of detonation). Where an explosive has been +used in coal or rock of a certain degree of brittleness, and where the +work of the explosive with that particular coal is not thoroughly +satisfactory, it becomes evident that through the systematic use of the +information available at the Testing Station (and now in course of +publication in the form of bulletins), in regard to the relationship +between percussive and heaving forces in different explosives, as shown +by the tests with small lead blocks, the Trauzl test, and the ballistic +pendulum, that explosives can be selected which, possessing in modified +form the properties of the explosive not entirely satisfactory in that +type of coal or rock, would combine all the favorable properties of the +first explosive, together with such additional advantages as would come +from its added adaptation to the material in which it is to be used.</p> + +<p> +For example, if the explosive in use were found to have too great a +shattering effect on the coal, an examination of the small lead-block +test of this explosive, and a comparison of this with lead-block tests +of other explosives having practically the same strength, as shown by +the ballistic pendulum, will enable the mine manager to select from +those already on the Permissible List (and therefore vouched for in +regard to safety in the presence of gas and coal dust, when used in a +proper way), some explosive which will have the same strength, and yet +which, because of lessened percussive force or shattering effect, will +produce coal in the manner desired. If one takes the other extreme, and +considers a mine in which the product is used exclusively for the +preparation of coke (and therefore where shattering of the coal is in no +way a disadvantage), the mine superintendent’s interest will be +primarily to select an explosive which, as indicated by suitable +lead-block, Trauzl, and ballistic pendulum tests, will produce the +greatest amount of coal at the least cost.</p> + +<p> +As the cost of the explosive does not form any part of the tables +prepared by the Testing Station, the relative cost must be computed from +the manufacturer’s prices, but the results tabulated by the Station will +contain all the other data necessary to give the mine superintendent +(who cares to take the small amount of trouble necessary to familiarize +himself with the tables) all the information which is required to +compare the action of one explosive with that of any other explosive +tested.</p> + +<p> +In this way it is seen that, aside from the primary consideration of +safety in the presence of explosive mixtures of fire-damp and coal dust +(a condition alike fulfilled by all explosives admitted to the +Permissible List), the data prepared by the Testing Station also give +the information necessary to enable the discriminating mine manager to +select an explosive adapted to the particular physical qualities of the +coal at his mine, or to decide intelligently between two explosives of +the same cost on the basis of their actual energy content +<!--png341--> +<span class = "pagenum">309</span> +<a name = "page309"> </a> +in the particular form of the heaving or percussive force required in +his work.</p> + +<p> +Up to the present time the investigations have been confined to +explosives used in coal mining, because the Act of Congress establishing +the Testing Station has thus limited its work. Accordingly, it is not +possible to compare, on the systematic basis just mentioned, the +explosives generally used in rock work. It is probable that, if the Bill +now before Congress in regard to the establishment of a Bureau of Mines +is passed, work of this character will be undertaken, and the tables of +explosives now prepared will be extended to cover all those intended for +general mining and quarrying use. Data of such character are +unobtainable to-day, and, as a result, a considerable percentage of +explosives now used in all mining operations is wasted, because of their +lack of adaptation to the materials being blasted. It is well known, for +example, that when an explosive of high percussive force is used in +excavating in a soft or easily compressed medium, a considerable +percentage of its force is wasted as heat energy, performing no other +function than the distortion and compression of the material in which it +is fired, without exerting either an appreciable cracking or fissuring +effect, or a heaving or throwing of the material.</p> + +<p> +Owing to lack of information in regard to the exact relationship between +the percussive and the heaving force in particular explosives, this +waste, as compared with the quantity required for the work with a +properly balanced material, will continue; but it is to be hoped that it +will soon be possible to give the mining and quarrying industries +suitable information in regard to the properties of the various +explosives, so that the railroad contractor and the metal miner may have +the same simple and exact means of discrimination between suitable and +unsuitable explosives that is now being provided for the benefit of the +coal miner.</p> + +<p> +Another of the important but indirect benefits of this work has been the +production of uniformity of strength and composition in explosives. An +example of this helpful influence is the standardization of detonating +caps and electric detonators. In the early days of the explosive +industry, it was apparently advantageous for each manufacturer to have a +separate system of trade nomenclature by which to designate the +strengths of the different detonators manufactured by him. The necessity +and even the advantage of such methods have long been outgrown, and yet, +until the past year, the explosive industry has had to labor under +conditions which made it almost impossible for the user of explosives to +compare, in cost or strength, detonators of different manufacturers; or +to select intelligently the detonator best suited to the explosive to be +used. After conference with the manufacturers of detonating caps and +electric detonators, a standard system of naming the strengths of these +products has been selected by the +<!--png342--> +<span class = "pagenum">310</span> +<a name = "page310"> </a> +Testing Station, and has met with a most hearty response. It is +encouraging to note that, in recent trade catalogues, detonators are +named in such a way as to enable the user to determine directly the +strength of the contained charge, which is a decided advantage to every +user of explosives and also to manufacturers.</p> + +<p> +The uniformity of composition of explosives (and many difficulties in +mining work and many accidents have been rightly or wrongly attributed +to lack of uniformity) may be considered as settled in regard to all +those on the Permissible List. One of the conditions required of every +explosive on that list is that its composition must continue +substantially the same as the samples submitted originally for official +test. Up to the present, all explosives admitted to the Permissible List +have maintained their original composition, as determined by subsequent +analyses of samples selected from mines in which the explosive was in +use, and comparison with the original samples.</p> + +<p> +The data assembled by the Testing Station in regard to particular +explosives have also been of great benefit to the manufacturers. When +the explosives tests were commenced, comparatively few explosives were +being made in the United States for which it was even claimed by the +manufacturers that they were at all safe in the presence of explosive +mixtures of gas or coal dust. It was evident that, without systematic +tests, very little knowledge of the safety or lack of safety of any +particular explosive could ever be gained, and, consequently, the user +of explosives was apt to regard with incredulity any claim by the +manufacturer in regard to the qualities of safety. Owing to lack of +proof, this was most natural; and it was also evident that the very slow +process of testing, which was offered by a study of mine explosions +during past years, was sufficient only to prove the danger of black +powder, and not in any way to indicate the safety of any of the brands +of mining powder for which this property was claimed. Indeed, one of the +few explosives to which the name, “safety,” was attached, at the time +the Government experiments were first undertaken, was found to be +anything but safe when tested in the gallery, although there is no +reason to believe that the makers of this and other explosives claiming +“safety” for their product, did not have the fullest confidence in their +safety.</p> + +<p> +The Testing Station offered the first opportunity in the United States +to obtain facts in regard to the danger of any particular explosive in +the presence of explosive mixtures of gas or coal dust. With most +commendable energy, the manufacturers of explosives, noting the early +failures of their powders in the testing gallery, began at once to +modify them in such ways as suggested by the behavior of the explosives +when under test, and, in a short time, returned to the Testing Station +with improved products, able to stand the severe +<!--png343--> +<span class = "pagenum">311</span> +<a name = "page311"> </a> +tests required. In this way the Testing Station has been a most active +agent in increasing the general safety of explosives, and the +manufacturers have shown clearly that it never was their desire to offer +inferior explosives to the public, but that their failures in the past +were due solely to lack of information in regard to the action of +explosives under the conditions which exist before a mine disaster. The +chance being offered to duplicate, at the Testing Station, the +conditions represented in a mine in the presence of gas, they showed an +eagerness to modify and improve their explosives so as to enable them to +answer severe mining conditions, which is most commendable to American +industry.</p> + +<p> +In regard to the unfavorable conditions existing in mines in the past, +the same arguments may be used. In spite of the frequency of mine +accidents in the United States, and in spite of the high death rate in +coal mining as compared with that in other countries, it must be said in +fairness that this has been the result of ignorance of the actual +conditions which produce mine explosions, rather than any willful +disregard of the known laws of safety by mine owners. Conditions in +American mines are far different from those obtaining in mines abroad, +and, as a result, the rules which years of experience had taught to +foreign colliery managers were not quickly applied to conditions +existing in American mines; but, as soon as the work at the Pittsburg +Station had demonstrated the explosibility of the coal dust from +adjoining mines, and had shown the very great safety of some explosives +as compared with others, there was at once a readiness on the part of +mine owners throughout the country to improve conditions in their mines, +and to take advantage of all the studies made by the Government, thus +showing clearly that the disasters of the past had been due to lack of +sufficient information rather that to any willful disregard of the value +of human lives.</p> + +<p> +Another of the indirect benefits of the work of the Station has resulted +from its examination of explosives for the Panama Canal. For several +years the Isthmian Canal Commission has been one of the largest users of +explosives in the world, and, in the purchase of the enormous quantities +required, it was found necessary to establish a system of careful +examination and inspection. This was done in order to insure the safety +of the explosives delivered on the Isthmus, and also to make certain +that the standards named in the contract were being maintained at all +times. With its established corps of chemists and engineers, it was +natural that this important work should be taken up by the Technologic +Branch of the United States Geological Survey, and, during the past +three years, many millions of pounds of dynamite have been inspected and +samples analyzed by the chemists connected with the Pittsburg Testing +Station, thus insuring the high standard of these materials.</p> + +<p> +<!--png344--> +<span class = "pagenum">312</span> +<a name = "page312"> </a> +One of the many ways in which this work for the Canal Commission has +proved of advantage is shown by the fact that, as a result of studies at +the Testing Station, electric detonators are being made to-day which, in +water-proof qualities, are greatly superior to any similar product. As +the improvements of these detonators were made by a member of the +testing staff, all the pecuniary advantages arising from them have gone +directly to the Government, which to-day is obtaining superior electric +detonators, and at a cost of about one-third of the price of the former +materials.</p> + +<p> +All the work of the Technologic Branch is being carried out along +eminently practical lines, and is far removed from such work as can be +taken up advantageously by private or by State agencies. The work of the +Mine Accidents Division was taken up primarily to reduce the number of +mine accidents, and to increase the general conditions of safety in +mining. As the work of this Division has progressed, it has been found +to be of great advantage to the miner and the mine owner, while the +ultimate results of the studies will be of still greater value to every +consumer of coal, as they will insure a continued supply of this +valuable product, and at a lower cost than if the present methods, +wasteful alike in lives and in coal, had been allowed to continue for +another decade.</p> + +<p class = "space"> +<span class = "sidenote"><a name = "disc_bartoccini">Mr.<br> +Bartoccini.</a></span> +<span class = "smallcaps">A. Bartoccini, Assoc. M. Am. Soc. +C. E.</span> (by letter).—The writer made a personal +investigation of the mine disaster of Cherry, Ill. He interviewed the +men who escaped on the day of the accident, and also several of those +who were rescued one week later. He also interrogated the superintendent +and the engineer of the mine, and obtained all the information asked for +and also the plans of the mine showing the progress of the work.</p> + +<p> +After a careful investigation the writer found that the following +conditions existed at the mine at the time of the disaster:</p> + +<p class = "hanging"> +<i>First.</i>—There were no means for extinguishing fires in the +mine.</p> + +<p class = "hanging"> +<i>Second.</i>—There were no signal systems of any kind. Had the +mine been provided with electric signals and telephones, like some of +the most modern mines in the United States, the majority of the men +could have been saved, by getting into communication with the outside +and working in conjunction with the rescuers.</p> + +<p class = "hanging"> +<i>Third.</i>—The miners had never received instructions of how to +behave in case of fire.</p> + +<p class = "hanging"> +<i>Fourth.</i>—The main entries and stables were lighted with open +torches.</p> + +<p class = "hanging"> +<i>Fifth.</i>—The organization of the mine was defective in some +way, for at the time of the disaster orders came from every +direction.</p> + +<p class = "hanging"> +<!--png345--> +<span class = "pagenum">313</span> +<a name = "page313"> </a> +<i>Sixth.</i>—The air shaft was used also as a hoisting shaft.</p> + +<p class = "hanging"> +<i>Seventh.</i>—The main shaft practically reached only to the +second vein; its extension to the third and deepest vein was not +used.</p> + +<p class = "hanging"> +<i>Eighth.</i>—Plans of the workings of the second and third veins +were not up to date. The last survey recorded on them was that of June, +1909. This would have made rescue work almost impossible to men not +familiar with the mine.</p> + +<p class = "hanging"> +<i>Ninth.</i>—The inside survey of the mine was not connected with +the outside survey.</p> + +<p> +Would it not be possible for the United States Geological Survey to +enforce rules which would prevent the existence of conditions such as +those mentioned? The Survey is doing wonderful work, as shown by the +rescue of twenty miners at Cherry one week after the conflagration; but +there is no doubt that perhaps all the men could have been saved if +telephone communications with the outside had been established. +Telephone lines to resist any kind of a fire, can easily be installed, +and the expense is small, almost negligible when one considers the +enormous losses suffered by the mine owners and by the families of the +victims.</p> + + +<p class = "space"> +<span class = "sidenote"><a name = "disc_stott">Mr.<br> +Stott.</a></span> +<span class = "smallcaps">H. G. Stott, M. Am. Soc. C. +E.</span>—The curves shown by Mr. Wilson give a clear general idea +of the relative efficiencies of steam and gas engines when treated from +a purely theoretical thermodynamic point of view. This point of view, +however, is only justified when small units having a maximum brake +horse-power not exceeding 1,000 are considered.</p> + +<p> +The steam engine or turbine operating under a gauge pressure of 200 lb. +per sq. in., and with 150° superheat, has a maximum temperature of 538° +Fahr. in its cylinder, while that of the gas engine varies between +2,000° and 3,000° Fahr.</p> + +<p> +The lubrication of a surface continually subjected to the latter +temperature would be impossible, so that water jackets on the cylinders +and, in the larger units, in the pistons become absolutely necessary. As +the cylinders increase in diameter, it is necessary, of course, to +increase their strength in proportion to their area, which, in turn, is +proportional to the square of the diameter. The cooling surface, +however, is only proportional to the circumference, or a single function +of the diameter. Increasing the strength in proportion to the square of +the diameter soon leads to difficulties, because of the fact that the +flow of heat through a metal is a comparatively slow process; the thick +walls of the cylinders on large engines cannot conduct the heat away +fast enough, and all sorts of strains are set up in the metal, due to +the enormous difference in temperature between the inside and the jacket +lining of the cylinder.</p> + +<p> +<!--png346--> +<span class = "pagenum">314</span> +<a name = "page314"> </a> +These conditions produce cut and cracked cylinders, with a natural +resultant of high maintenance and depreciation costs. These costs, in +some cases, have been so great, not only in the United States, but in +Europe and Africa, as to cause the complete abandonment of large gas +engine plants after a few years of attempted operation.</p> + +<p> +The first consideration in any power plant is that it shall be +thoroughly reliable in operation, and the second is that it shall be +economical, not only in operation, but in maintenance and depreciation. +Therefore, in using the comparative efficiency curves shown in Mr. +Wilson’s paper it should be kept in mind that the cost of power is not +only the fuel cost, but the fuel plus the maintenance and depreciation +charges, and that the latter items should not be taken from the first +year’s account, but as an average of at least five years.</p> + +<p> +The small gas engine is a very satisfactory apparatus when supplied with +good, clean gas, and when given proper attention, but great caution +should be used before investing in large units, until further +developments in the art take place, as conservation of capital is just +as important as conservation of coal.</p> + + +<p class = "space"> +<span class = "sidenote"><a name = "disc_dunn">Mr.<br> +Dunn.</a></span> +<span class = "smallcaps">B. W. Dunn, Esq.</span><a class = "tag" name = +"tag31" href = "#note31">31</a> (by letter.)—The growing +importance of investigations of explosives, with a view to increasing +the consumer’s knowledge of proper methods for handling and using them, +is evident when it is noted that the total production of explosives in +the United States has grown from less than 9,000,000 lb. in 1840 to +about 215,000,000 lb. in 1905. Table 5 has been compiled by the Bureau +of Explosives of the American Railway Association.</p> + +<h5 class = "smallcaps">TABLE 5.—Manufacture of Explosives in the +United States, 1909.</h5> + +<table class = "lines"> +<tr class = "lines"> +<th rowspan = "2">Kind of explosives.</th> +<th class = "leftline" rowspan = "2">Number of<br> +factories.</th> +<th class = "leftline smallcaps" colspan = "2">Maximum Capacity, in +Pounds.</th> +</tr> +<tr class = "lines"> +<th class = "leftline">Daily.</th> +<th class = "leftline">Annual.</th> +</tr> +<tr> +<td>Black powder</td> +<td class = "middle leftline">49</td> +<td class = "number leftline">1,220,150</td> +<td class = "number leftline">366,135,000</td> +</tr> +<tr> +<td>High explosives</td> +<td class = "middle leftline">37</td> +<td class = "number leftline">1,203,935</td> +<td class = "number leftline">361,180,500</td> +</tr> +<tr> +<td>Smokeless powders</td> +<td class = "middle leftline"> 5</td> +<td class = "number leftline">75,686</td> +<td class = "number leftline">22,705,800</td> +</tr> +</table> + +<p> +The first problem presented by this phenomenal increase relates to the +safe transportation of this material from the factories to points of +consumption. A package of explosives may make many journeys through +densely populated centers, and rest temporarily in many widely separated +storehouses before it reaches its final destination. A comprehensive +view of the entire railway mileage of the United States would show at +any instant about 5,000 cars partially or completely loaded with +explosives. More than 1,200 storage magazines are listed by the Bureau +of Explosives as sources of shipments of explosives by rail.</p> + +<p> +<!--png347--> +<span class = "pagenum">315</span> +<a name = "page315"> </a> +The increase in the demand for explosives has not been due entirely to +the increase in mining operations. The civil engineer has been expanding +his use of them until now carloads of dynamite, used on the Isthmus of +Panama in a single blast, bring to the steam shovels as much as 75,000 +cu. yd. of material, the dislodgment of which by manual labor would have +required days of time and hundreds of men. Without the assistance of +explosives, the construction of subways and the driving of tunnels would +be impracticable. Even the farmer has awakened to the value of this +concentrated source of power, and he uses it for the cheap and effective +uprooting of large stumps over extended areas in Oregon, while an entire +acre of subsoil in South Carolina, too refractory for the plow, is +broken up and made available for successful cultivation by one explosion +of a series of well-placed charges of dynamite. It has also been found +by experience that a few cents’ worth of explosive will be as effective +as a dollar’s worth of manual labor in preparing holes for transplanting +trees.</p> + +<p> +The use of explosives in war and in preparation for war is now almost a +negligible quantity when compared with the general demand from peaceful +industries. With the completion of the Panama Canal, it is estimated +that the Government will have used in that work alone more explosives +than have been expended in all the battles of history.</p> + +<p> +Until a few years ago little interest was manifested by the public in +safeguarding the manufacture, transportation, storage, and use of +explosives. Anyone possessing the necessary degree of ignorance, or +rashness, was free to engage in their manufacture with incomplete +equipment; they were transported by many railroads without any special +precautions; the location of magazines in the immediate vicinity of +dwellings, railways, and public highways, was criticized only after some +disastrous explosion; and the often inexperienced consumer was without +access to a competent and disinterested source of information such as he +now has in the testing plant at Pittsburg so well described by Mr. +Wilson.</p> + +<p> +The first general move to improve these conditions is believed to have +been made by the American Railway Association in April, 1905. It +resulted in the organization of a Bureau of Explosives which, through +its inspectors, now exercises supervision over the transportation of all +kinds of dangerous articles on 223,630 of the 245,000 miles of railways +in the United States and Canada. A general idea of the kind and volume +of inspection work is shown by the following extracts from the Annual +Report of the Chief Inspector, dated February, 1910:</p> + +<div class = "rules"> + +<table class = "quotation"> +<tr> +<td></td> +<td class = "number ital">1909.</td> +<td class = "number ital">1908.</td> +</tr> +<tr> +<td><div class = "hanging"> +“Total number of railway lines members of Bureau December 31st +</div></td> +<td class = "number">172</td> +<td class = "number">158</td> +</tr> +<tr> +<td><div class = "hanging"> +Total mileage of Bureau lines December 31st +</div></td> +<td class = "number">209,984</td> +<td class = "number">202,186</td> +</tr> +<tr> +<td><div class = "hanging"> +Total number of inspections of stations for explosives +</div></td> +<td class = "number">6,953</td> +<td class = "number">5,603</td> +</tr> +<tr> +<td><div class = "hanging"> +Number of stations receiving two or more inspections for explosives +</div></td> +<td class = "number">1,839</td> +<td class = "number">1,309</td> +</tr> +<tr> +<td><div class = "hanging"> +<!--png348--> +<span class = "pagenum">316</span> +<a name = "page316"> </a> +Total number of inspections of stations for inflammables +</div></td> +<td class = "number">6,950</td> +<td class = "number">1,098</td> +</tr> +<tr> +<td><div class = "hanging"> +Number of stations receiving two or more inspections for inflammables +</div></td> +<td class = "number">1,886</td> +<td class = "number">....</td> +</tr> +<tr> +<td><div class = "hanging"> +Total number of inspections of factories +</div></td> +<td class = "number">278</td> +<td class = "number">270</td> +</tr> +<tr> +<td><div class = "hanging"> +Number of factories receiving two or more inspections +</div></td> +<td class = "number">75</td> +<td class = "number">69</td> +</tr> +<tr> +<td><div class = "hanging"> +Total number of inspections of magazines +</div></td> +<td class = "number">1,293</td> +<td class = "number">1,540</td> +</tr> +<tr> +<td><div class = "hanging"> +Number of magazines receiving two or more inspections +</div></td> +<td class = "number">349</td> +<td class = "number">361</td> +</tr> +<tr> +<td><div class = "hanging"> +Total number of boxes of high explosives condemned as unsafe for +transportation +</div></td> +<td class = "number">10,029</td> +<td class = "number">4,852</td> +</tr> +<tr> +<td><div class = "hanging"> +Total number of kegs of black powder condemned as unsafe for +transportation +</div></td> +<td class = "number">1,468</td> +<td class = "number">531</td> +</tr> +<tr> +<td><div class = "hanging"> +Total number of cars in transit containing explosives inspected +</div></td> +<td class = "number">475</td> +<td class = "number">448</td> +</tr> +<tr> +<td><div class = "hanging"> +Total number of cars in transit showing serious violations of the +regulations +</div></td> +<td class = "number">168</td> +<td class = "number">197</td> +</tr> +<tr> +<td><div class = "hanging"> +Total number of inspections of steamship companies’ piers (inflammable, +75; explosive, 63) +</div></td> +<td class = "number">138</td> +<td class = "number">....</td> +</tr> +<tr> +<td><div class = "hanging"> +Total number of inspections made by Bureau +</div></td> +<td class = "number">16,087</td> +<td class = "number">8,959</td> +</tr> +<tr> +<td><div class = "hanging"> +Total number of lectures to railway officials and employes and meetings +addressed on the subject of safe transportation of explosives and other +dangerous articles +</div></td> +<td class = "number">215</td> +<td class = "number">171</td> +</tr> +</table> + +<table class = "quotation"> +<tr> +<td></td> +<td class = "number ital">1909.</td> +<td class = "number ital">1908.</td> +<td class = "number ital">1907.</td> +</tr> +<tr> +<td><div class = "hanging"> +“Total number of accidents resulting in explosions or fires in +transportation of explosives by rail +</div></td> +<td class = "number">12</td> +<td class = "number">22</td> +<td class = "number">79</td> +</tr> +<tr> +<td><div class = "hanging"> +Total known property loss account explosions or accidents in +transporting explosives by rail +</div></td> +<td class = "number">$2,673</td> +<td class = "number">$114,629</td> +<td class = "number">$496,820</td> +</tr> +<tr> +<td><div class = "hanging"> +Total number of persons injured by explosions in transit +</div></td> +<td class = "number">7</td> +<td class = "number">53</td> +<td class = "number">80</td> +</tr> +<tr> +<td><div class = "hanging"> +Total number of persons killed by explosions in transit +</div></td> +<td class = "number">6</td> +<td class = "number">26</td> +<td class = "number">52</td> +</tr> +</table> + +<p> +“During the same period reports have been rendered to the Chief +Inspector by the Chemical Laboratory of the Bureau on 734 samples, as +follows:</p> + +<table class = "quotation inline"> +<tr> +<td>Explosives</td> +<td class = "number">211</td> +</tr> +<tr> +<td>Fireworks</td> +<td class = "number">186</td> +</tr> +<tr> +<td>Inflammables</td> +<td class = "number">304</td> +</tr> +<tr> +<td>Paper for lining high explosive boxes</td> +<td class = "number">31</td> +</tr> +<tr> +<td>Ammunition</td> +<td class = "number underline">2</td> +</tr> +<tr> +<td>Total</td> +<td class = "number">734</td> +</tr> +</table> + +<p> +“As a means of ensuring the uniform enforcement of the regulations, by a +well grounded appreciation of their significance and application, the +lectures delivered by representatives of the Bureau have +<!--png349--> +<span class = "pagenum">317</span> +<a name = "page317"> </a> +proved most successful. The promulgation of the regulations is not of +itself sufficient to ensure uniformity or efficiency in their +observance, and so these lectures form a valuable supplement to the +inspection service. They have been successfully continued throughout the +year, and the requests for the delivery of them by the managements of so +many of the membership lines, is a convincing testimonial of the high +esteem in which they are held.</p> + +<p> +“While the lectures are primarily intended for the instruction and +information of the officials and employes of the railway companies, and +especially of those whose duties bring them into immediate contact with +the dangerous articles handled in transportation, the manufacturers and +shippers are invited, and they have attended them in considerable +numbers. Many of this class have voluntarily expressed their +commendation of the lectures as a medium of education, and signified +their approval of them in flattering terms.</p> + +<p> +“The scope of these lectures embraces elementary instruction in the +characteristics of explosives and inflammables and the hazards +encountered in their transportation and in what respects the regulations +afford protection against them. The requirements of the law, and the +attendant penalties for violation, are fully described. Methods of +preparation, packing, marking, receiving, handling and delivering, are +explained by stereopticon lantern slides. These are interesting of +themselves, and are the best means of stamping the impression they are +intended to convey upon the minds of the audiences, and are always an +acceptable feature of the lectures. The reception generally given to the +lectures by those who have attended them, often at the voluntary +surrender of time intended for rest while off duty, may be stated as an +indication that the subject matter is one in which they are +interested.</p> + +<p> +“The facilities of the Young Men’s Christian Association, in halls, +lanterns and skilled lantern operators, have been generously accorded +and made use of to great advantage, in connection with the lectures at +many places. The co-operation of this Association affords a convenient +and economical method of securing the above facilities, and the +Association has expressed its satisfaction with the arrangement as in +line with the educational features which they provide for their +members.</p> + +<p> +“During the year 1909, 215 lectures were delivered at various points +throughout the United States.”</p> +</div> + +<p> +The Bureau of Explosives, of the American Railway Association, and the +Bureau of Mines, of the United States Geological Survey, were +independent products of a general agitation due to the appreciation by a +limited number of public-spirited citizens of the gravity of the +“explosive” problem. It is the plain duty of the average citizen to +become familiar with work of this kind prosecuted in his behalf. He may +be able to help the work by assisting to overcome misguided opposition +to it. Evidences of this opposition may be noted in the efforts of some +shippers to avoid the expense of providing suitable shipping containers +for explosives and inflammable articles, and in the threats of miners’ +labor unions to strike rather than use permissible explosives instead of +black powder in mining coal in gaseous or dusty mines.</p> + +<p> +Too much credit cannot be given Messrs. Holmes and Wilson, and +<!--png350--> +<span class = "pagenum">318</span> +<a name = "page318"> </a> +other officials of the Technologic Branch of the United States +Geological Survey, for the investigations described in this paper. They +are establishing reasonable standards for many structural materials; +they are teaching the manufacturer what he can and should produce, and +the consumer what he has a right to demand; with scientific accuracy +they are pointing the way to a conservation of our natural resources and +to a saving of life which will repay the nation many times for the cost +of their work.</p> + +<p> +When these facts become thoroughly appreciated and digested by the +average citizen, these gentlemen and their able assistants will have no +further cause to fear the withdrawal of financial or moral support for +their work.</p> + +<p class = "space"> +<span class = "sidenote"><a name = "disc_wilson">Mr.<br> +Wilson.</a></span> +<span class = "smallcaps">Herbert M. Wilson, M. Am. Soc. C. E.</span> +(by letter).—The Fuel Division of the United States Geological +Survey has given considerable attention to the use of peat as a fuel for +combustion under boiler furnaces, in gas producers, and for other +purposes. It is doubtless to this material that Mr. Allen refers in +speaking of utilizing “marsh mud for fuel,” since he refers to an +address by Mr. Edward Atkinson on the subject of “Bog Fuel” in which he +characterized peat by the more popular term “marsh mud.”</p> + +<p> +In Europe, where fuel is expensive, 10,000,000 tons of peat are used +annually for fuel purposes. A preliminary and incomplete examination, +made by Mr. C. A. Davis, of the Fuel Division of the Geological +Survey, indicates that the peat beds of the United States extend +throughout an area of more than 11,000 sq. miles. The larger part of +this is in New England, New York, Minnesota, Wisconsin, New Jersey, +Virginia, and other Coastal States which contain little or no coal. It +has been estimated that this area will produce 13,000,000,000 tons of +air-dried peat.</p> + +<p> +At present peat production is in its infancy in the United States, +though there are in operation several commercial plants which find a +ready market for their product and are being operated at a profit. A +test was made at the Pittsburg plant on North Carolina peat operated in +a gas producer—the resulting producer gas being used to run a gas +engine of 150 h.p.—the load on which was measured on a +switch-board. Peat containing nearly 30% of ash and 15% of water gave 1 +commercial horse-power-hour for each 4 lb. of peat fired in the +producer. Had the peat cost $2 per ton to dig and prepare for the +producer, each horse-power-hour developed would have cost 0.4 of a cent. +The fuel cost of running an electric plant properly equipped for using +peat fuel, of even this low grade, in the gas producer would be about $4 +per 100 h.p. developed per 10-hour day.</p> + +<p> +Equally good results were procured in tests of Florida and Michigan peat +operated in the gas producer. The investigations of peat under Mr. Davis +include studies of simple commercial methods of drying, the chemical and +fuel value, analyses of the peat, studies of the +<!--png351--> +<span class = "pagenum">319</span> +<a name = "page319"> </a> +mechanical methods of digging and disintegrating the peat, and physical +tests to determine the strength of air-dried peat to support a load.</p> + +<p> +The calorific value of peat, as shown by numerous analyses made by the +United States Geological Survey, runs from about 7,500 to nearly 11,000 +B.t.u., moisture free, including the ash, which varies from less than 2% +to 20%, the latter being considered in Europe the limit of commercial +use for fuel. Analyses of 25 samples of peat from Florida, within these +limits as to ash, show a range of from 8,269 to 10,865 B.t.u., only four +of the series being below 9,000 B.t.u., and four exceeding 10,500 +B.t.u., moisture free. Such fuel in Florida is likely to be utilized +soon, since it only needs to be dug and dried in order to render it fit +for the furnace or gas producer. Many bituminous coals now used +commercially have fuel value as low as 11,000 B.t.u., moisture free, and +with maximum ash content of 20%; buckwheat anthracite averages near the +same figures, often running as high as 24% ash.</p> + +<p> +One bulletin concerning the peats of Maine has been published, and +another, concerning the peat industries of the United States, is in +course of publication.</p> + +<p> +Mr. Bartoccini asks whether it would not be possible for the United +States Geological Survey to enforce rules which would prevent the +existence of conditions such as occurred at the mine disaster of +Cherry, Ill.</p> + +<p> +The United States Government has no police power within the States, and +it is not within its province to enact or enforce rules or laws, or even +to make police inspection regarding the methods of operating mining +properties. The province of the mine accidents investigations and that +of its successor, the Bureau of Mines, is, within the States, like that +of other and similar Government bureaus in the Interior Department, the +Department of Agriculture, and other Federal departments, merely to +investigate and disseminate information. It remains for the States to +enact laws and rules applying the remedies which may be indicated as a +result of Federal investigation.</p> + +<p> +Investigations are now in progress and tests are being conducted with a +view to issuing circulars concerning the methods of fighting mine fires, +the installation of telephones and other means of signaling, and other +subjects of the kind to which Mr. Bartoccini refers.</p> + +<p> +Much as the writer appreciates the kindly and sympathetic spirit of the +discussion of Messrs. Allen and Bartoccini, he appreciates even more +that of Colonel Dunn and Mr. Stott, who are recognized authorities +regarding the subjects they discuss, and of Messrs. Kreisinger and +Snelling, who have added materially to the details presented in the +paper relative to the particular investigations of which they have +charge in Pittsburg.</p> + +<p> +Mr. Snelling’s reference to the use of explosives in blasting operations +<!--png352--> +<span class = "pagenum">320</span> +<a name = "page320"> </a> +should be of interest to all civil engineers, as well as to mining +engineers, as should Colonel Dunn’s discussion concerning the means +adopted to safeguard the transportation of explosives.</p> + +<p> +Since the presentation of the paper, Congress has enacted a law +establishing, in the Department of the Interior, a United States Bureau +of Mines. To this Bureau have been transferred from the Geological +Survey the fuel-testing and the mine accidents investigations described +in this paper. To the writer it seems a matter for deep regret that the +investigations of the structural materials belonging to and for the use +of the United States, were not also transferred to the same Bureau. On +the last day of the session of Congress, a conference report transferred +these from the Geological Survey to the Bureau of Standards. It is +doubtful whether the continuation of these investigations in that +Bureau, presided over as it is by physicists and chemists of high +scientific attainments, will be of as immediate value to engineers and +to those engaged in building and engineering construction as they would +in the Bureau of Mines, charged as it is with the investigations +pertinent to the mining and quarrying industries, and having in its +employ mining, mechanical, and civil engineers.</p> + +<hr class = "section"> +<h4>Footnotes</h4> + +<div class = "footnote"><a name = "note1" href = "#tag1">1.</a> +Presented at the meeting of April 20th, 1910.</div> + +<div class = "footnote"><a name = "note2" href = "#tag2">2.</a> +“Coal Mine Accidents,” by Clarence Hall and Walter O. Snelling. Bulletin +No. 333, U. S. Geological Survey, Washington, D. C.</div> + +<div class = "footnote"><a name = "note3" href = "#tag3">3.</a> +“The Explosibility of Coal Dust,” by George S. Rice and others. Bulletin +No. * * *, U. S. Geological Survey.</div> + +<div class = "footnote"><a name = "note4" href = "#tag4">4.</a> +“Notes on Explosives, Mine Gases and Dusts,” by Rollin Thomas +Chamberlin. Bulletin No. 383, U. S. Geological Survey, 1909.</div> + +<div class = "footnote"><a name = "note5" href = "#tag5">5.</a> +“Prevention of Mine Explosions,” by Victor Watteyne, Carl Meissner, and +Arthur Desborough. Bulletin No. 369, U. S. Geological Survey.</div> + +<div class = "footnote"><a name = "note6" href = "#tag6">6.</a> +With a view to obtaining a dust of uniform purity and +inflammability.</div> + +<div class = "footnote"><a name = "note7" href = "#tag7">7.</a> +“The Primer of Explosives,” by C. E. Munroe and Clarence Hall. +Bulletin No. 423, U. S. Geological Survey, 1909.</div> + +<div class = "footnote"><a name = "note8" href = "#tag8">8.</a> +“Tests of Permissible Explosives,” by Clarence Hall, W. O. +Snelling, S. P. Howell, and J. J. Rutledge. Bulletin No. +* * *, U. S. Geological Survey.</div> + +<div class = "footnote"><a name = "note9" href = "#tag9">9.</a> +“Structural Materials Testing Laboratories,” by Richard L. Humphrey, +Bulletin No. 329. U. S. Geological Survey, 1908; “Portland Cement +Mortars and their Constituent Materials,” by Richard L. Humphrey and +William Jordan, Jr., Bulletin No. 331, U. S. Geological Survey, +1908; “Strength of Concrete Beams,” by Richard L. Humphrey, Bulletin No. +344, U. S. Geological Survey, 1908.</div> + +<div class = "footnote"><a name = "note10" href = "#tag10">10.</a> +“Fire Resistive Properties of Various Building Materials,” by Richard L. +Humphrey, Bulletin No. 370, U. S. Geological Survey, 1909.</div> + +<div class = "footnote"><a name = "note11" href = "#tag11">11.</a> +“Purchasing Coal Under Government Specifications,” by J. S. +Burrows, Bulletin No. 378, U. S. Geological Survey, 1909.</div> + +<div class = "footnote"><a name = "note12" href = "#tag12">12.</a> +“Experimental Work in the Chemical Laboratory,” by N. W. Lord, +Bulletin No. 323, U. S. Geological Survey, 1907: “Operations of the +Coal Testing Plant, St. Louis, Mo.” Professional Paper No. 48, +U. S. Geological Survey, 1906.</div> + +<div class = "footnote"><a name = "note13" href = "#tag13">13.</a> +Also Bulletins Nos. 290, 332, 334, 363, 366, 367, 373, 402, 403, and +412, U. S. Geological Survey.</div> + +<div class = "footnote"><a name = "note14" href = "#tag14">14.</a> +“Tests of Coal for House Heating Boilers,” by D. T. Randall, +Bulletin No. 336, U. S. Geological Survey, 1908.</div> + +<div class = "footnote"><a name = "note15" href = "#tag15">15.</a> +“The Smokeless Combustion of Coal,” by D. T. Randall and H. W. +Weeks, Bulletin No. 373, U. S. Geological Survey, 1909.</div> + +<div class = "footnote"><a name = "note16" href = "#tag16">16.</a> +“The Flow of Heat through Furnace Walls,” by W. T. Ray and H. +Kreisinger. Bulletin (in press), U. S. Geological Survey.</div> + +<div class = "footnote"><a name = "note17" href = "#tag17">17.</a> +The assumption is made that a metal tube free from scale will remain +almost as cool as the water; actual measurements with thermo-couples +have indicated the correctness of this assumption in the majority of +cases.</div> + +<div class = "footnote"><a name = "note18" href = "#tag18">18.</a> +“Heat Transmission into Steam Boilers,” by W. T. Ray and H. +Kreisinger, Bulletin (in press), U. S. Geological Survey.</div> + +<div class = "footnote"><a name = "note19" href = "#tag19">19.</a> +“The Producer Gas Power Plant,” by R. H. Fernald, Bulletin No. 416, +U. S. Geological Survey, 1909; also Professional Paper No. 48 and +Bulletins Nos. 290, 316, 332, and 416.</div> + +<div class = "footnote"><a name = "note20" href = "#tag20">20.</a> +A Taylor up-draft pressure producer, made by R. D. Wood and +Company, Philadelphia, Pa.</div> + +<div class = "footnote"><a name = "note21" href = "#tag21">21.</a> +“Coal Testing Plant, St. Louis, Mo.,” by R. H. Fernald, +Professional Paper No. 48, Vol. III, U. S. Geological Survey, +1906.</div> + +<div class = "footnote"><a name = "note22" href = "#tag22">22.</a> +A report of these tests may be found in Bulletin No. * * *, +U. S. Geological Survey.</div> + +<div class = "footnote"><a name = "note23" href = "#tag23">23.</a> +“Illuminating Gas Coals,” by A. H. White and Perry Barker, +U. S. Geological Survey.</div> + +<div class = "footnote"><a name = "note24" href = "#tag24">24.</a> +“Gasoline and Alcohol Tests,” by R. M. Strong, Bulletin No. 392, +U. S. Geological Survey, 1909.</div> + +<div class = "footnote"><a name = "note25" href = "#tag25">25.</a> +“Washing and Coking Tests,” by Richard Moldenke, A. W. Belden and +G. R. Delamater, Bulletin No. 336, U. S. Geological Survey, +1908; also, “Washing and Coking Tests at Denver, Colo.,” by A. W. +Belden and G. R. Delamater, Bulletin No. 368, U. S. Geological +Survey, 1909.</div> + +<div class = "footnote"><a name = "note26" href = "#tag26">26.</a> +U. S. Geological Survey, Professional Paper No. 48, Pt. III, and +Bulletins Nos. 290, 332, 336, 368, 385, and 403.</div> + +<div class = "footnote"><a name = "note27" href = "#tag27">27.</a> +Professional Paper No. 48, and Bulletins Nos. 290, 316, 332, 343, 363, +366, 385, 402, 403, and 412, U. S. Geological Survey.</div> + +<div class = "footnote"><a name = "note28" href = "#tag28">28.</a> +“Peat Deposits of Maine,” by E. D. Bastin and C. A. Davis. +Bulletin No. 376, U. S. Geological Survey, 1909.</div> + +<div class = "footnote"><a name = "note29" href = "#tag29">29.</a> +U. S. Geological Survey, Pittsburg, Pa.</div> + +<div class = "footnote"><a name = "note30" href = "#tag30">30.</a> +Chief Explosives Chemist, U. S. Geological Survey.</div> + +<div class = "footnote"><a name = "note31" href = "#tag31">31.</a> +Lieutenant-Colonel, Ordnance Dept., U. S. A.</div> + +<hr class = "mid chapter"> + +<div class = "mynote"> +<h5 class = "nospace"><a name = "fractions">Fractions +(Expanded)</a></h5> +Ellipses (...) represent omitted text at beginning or end of a +paragraph. For consistency, common fractions such as ½ have also been +expanded.</div> + +<p><i>Gas and Dust Gallery No. 1.</i>—Gallery No. 1 is cylindrical +in form, 100 ft. long, and has a minimum internal diameter of 6 1/3 +ft. It consists of fifteen similar sections, each 6 2/3 ft. long +and built up in in-and-out courses. The first three sections, those +nearest the concrete head, are of 1/2-in. boiler-plate steel, the +remaining twelve sections are of 3/8-in. boiler-plate steel, and have a +tensile strength of, at least, 55,000 lb. per sq. in....</p> + +<p>...The beam, from which the mortar is suspended, rests on concrete +walls, 51 by 120 in. at the base and 139 in. high. On top of each wall +is a 1-in. base-plate, 7 by 48 in., anchored to the wall by 5/8-in. +bolts, 28 in. long....</p> + +<p>This apparatus is in the southeast corner of Building No. 17. The +cylinder is 31 1/2 in. long, 19 1/4 in. in diameter, and is +anchored to a solid concrete footing at a convenient height for +handling. The explosion chamber is 19 in. long and 7 7/8 in. in +diameter, with a capacity of exactly 15 liters....</p> + +<p>The inner receiver is made of 1/16-in. sheet copper, 30 7/8 in. +deep, and with an inner diameter of 17 7/8 in. It is nickel-plated, +and strengthened on the outside with bands of copper wire, and its +capacity is about 70 liters....</p> + +<p>...In the front of the box are two plate-glass observing windows, +2 5/8 by 5 1/2 in. In the side of the box, between the two +windows, is a 3/8-in. hole, which can be closed by a tap-screw, through +which samples for chemical analysis are drawn.</p> + +<p>There is some variety in the cupboards and tables provided in the +various laboratories, but, in general, they follow the design shown in +<a href = "#fig_13">Fig. 13</a>. The table tops, 12 ft. long, are +of clear maple in full-length pieces, 7/8 in. thick and 2 5/8 in. +wide, laid on edge and drilled at 18-in. intervals for bolts. These +pieces are glued and drawn together by the bolts, the heads of which are +countersunk. The tops, planed off, sanded, and rounded, are supported on +pipe legs and frames of 1 1/4 by 1 1/2-in. galvanized-iron +pipe with screw flanges fitting to the floor and top. Under the tops are +drawers and above them re-agent shelves. Halfway between the table top +and the floor is a wire shelf of a frame-work of No. 2 wire interlaced +with No. 12 weave of 5/8-in. square mesh.</p> + +<p>...The fineness of the coals put through the hammer crusher varies +somewhat, but the average, taken from a large number of samples, is as +follows: Through 1/8-in. mesh, 100%; over 10-mesh, 31.43%; over 20-mesh, +24.29%; over 40-mesh, 22.86%; over 60-mesh, 10 per cent....</p> + + + + + + + + +<pre> + + + + + +End of the Project Gutenberg EBook of Transactions of the American Society +of Civil Engineers, vol. LXX, Dec. 1, by Herbert M. 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Anyone seeking to utilize +this eBook outside of the United States should confirm copyright +status under the laws that apply to them. diff --git a/README.md b/README.md new file mode 100644 index 0000000..1ab9b75 --- /dev/null +++ b/README.md @@ -0,0 +1,2 @@ +Project Gutenberg (https://www.gutenberg.org) public repository for +eBook #18448 (https://www.gutenberg.org/ebooks/18448) diff --git a/old/18448-8.txt b/old/18448-8.txt new file mode 100644 index 0000000..15dc7f6 --- /dev/null +++ b/old/18448-8.txt @@ -0,0 +1,6000 @@ +The Project Gutenberg EBook of Transactions of the American Society of +Civil Engineers, vol. LXX, Dec. 1910, by Herbert M. Wilson + +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: Transactions of the American Society of Civil Engineers, vol. LXX, Dec. 1910 + Federal Investigations of Mine Accidents, Structural + Materials and Fuels. Paper No. 1171 + +Author: Herbert M. Wilson + +Release Date: May 25, 2006 [EBook #18448] + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK SOCIETY OF CIVIL ENGINEERS *** + + + + +Produced by Louise Hope, Juliet Sutherland and the Online +Distributed Proofreading Team at http://www.pgdp.net + + + + + + [Transcriber's Note: + All footnotes are grouped at the end of the file. Those that include + non-bibliographic information are _also_ shown after their referring + paragraph.] + + * * * * * + + AMERICAN SOCIETY OF CIVIL ENGINEERS + Instituted 1852 + + TRANSACTIONS + + Paper No. 1171 + + FEDERAL INVESTIGATIONS OF MINE ACCIDENTS, + STRUCTURAL MATERIALS, AND FUELS.[1] + + By HERBERT M. WILSON, M. Am. Soc. C. E. + + With Discussion by Messrs. KENNETH ALLEN, + HENRY KREISINGER, WALTER O. SNELLING, + A. BARTOCCINI, H. G. STOTT, B. W. DUNN, + and HERBERT M. WILSON. + + +INTRODUCTION. + +The mine disaster, which occurred at Cherry, Ill., on November 13th, +1909, when 527 men were in the mine, resulting in the entombment of 330 +men, of whom 310 were killed, has again focused public attention on the +frequent recurrence of such disasters and their appalling consequences. +Interest in the possible prevention of such disasters, and the possible +means of combating subsequent mine fires and rescuing the imprisoned +miners, has been heightened as it was not even by the series of three +equally extensive disasters which occurred in 1907, for the reason that, +after the Cherry disaster, 20 men were rescued alive after an entombment +of one week, when practically all hope of rescuing any of the miners had +been abandoned. + +This accident, occurring, as it does, a little more than 1 years after +the enactment of legislation by Congress instructing the Director of the +United States Geological Survey to investigate the causes and possible +means of preventing the loss of life in coal-mining operations, makes +this an opportune time to review what has been done by the Geological +Survey during this time, toward carrying out the intent of this Act. + +It may be stated with confidence, that had such a disaster occurred a +year or more ago, all the entombed men must have perished, as it would +have been impossible to enter the mine without the protection afforded +by artificial respiratory apparatus. Moreover, but for the presence of +the skilled corps of Government engineers, experienced by more than a +year's training in similar operations in more than twenty disasters, the +mine would have been sealed until the fire had burned out, and neither +the dead, nor those who were found alive, would have been recovered for +many weeks. In the interval great suffering and loss would have been +inflicted on the miners, because of enforced idleness, and on the mine +owners because of continued inability to re-open and resume operations. + +_Character of the Work._--The United States Geological Survey has been +engaged continuously since 1904 in conducting investigations relating to +structural materials, such as stone, clay, cement, etc., and in making +tests and analyses of the coals, lignites, and other mineral fuel +substances, belonging to, and for the use of, the Government. + +Incidentally, the Survey has been considering means to increase +efficiency in the use of these resources as fuels and structural +materials, in the hope that the investigations will lead to their best +utilization. + +These inquiries attracted attention to the waste of human life incident +to the mining of fuel and its preparation for the market, with the +result that, in May, 1908, provision was made by Congress for +investigations into the causes of mine explosions with a view to their +prevention. + +Statistics collected by the Geological Survey show that the average +death rate in the coal mines of the United States from accidents of all +kinds, including gas and dust explosions, falls of roof, powder +explosions, etc., is three times that of France, Belgium, or Germany. On +the other hand, in no country in the world are natural conditions so +favorable for the safe extraction of coal as in the United States. In +Belgium, foremost in the study of mining conditions, a constant +reduction in the death rate has been secured, and from a rate once +nearly as great as that of the United States, namely, 3.28 per thousand, +in the period 1851-60, it had been reduced to about 2 per thousand in +the period 1881-90; and in the last decade this has been further reduced +to nearly 1 per thousand. It seems certain, from the investigations +already made by the Geological Survey, that better means of safeguarding +the lives of miners will be found, and that the death rate from mine +accidents will soon show a marked reduction. + +Other statistics collected by the Geological Survey show that, to the +close of 1907, nearly 7,000,000,000 tons of coal had been mined in the +United States, and it is estimated that for every ton mined nearly a ton +has been wasted, 3,500,000,000 tons being left in the ground or thrown +on the dump as of a grade too low for commercial use. To the close of +1907 the production represents an exhaustion of somewhat more than +10,000,000,000 tons of coal. It has been estimated that if the +production continues to increase, from the present annual output of +approximately 415,000,000 tons, at the rate which has prevailed during +the last fifty years, the greater part of the more accessible coal +supply will be exhausted before the middle of the next century. + +The Forest Service estimates that, at the present rate of consumption, +renewals of growth not being taken into account, the timber supply will +be exhausted within the next quarter of a century. It is desirable, +therefore, that all information possible be gained regarding the most +suitable substitutes for wood for building and engineering construction, +such as iron, stone, clay products, concrete, etc., and that the minimum +proportion in which these materials should be used for a given purpose, +be ascertained. Exhaustion, by use in engineering and building +construction, applies not only to the iron ore, clay, and cement-making +materials, but, in larger ratio, to the fuel essential to rendering +these substances available for materials of construction. Incidentally, +investigations into the waste of structural materials have developed the +fact that the destructive losses, due to fires in combustible buildings, +amount to more than $200,000,000 per annum. A sum even greater than this +is annually expended on fire protection. Inquiries looking to the +reduction of fire losses are being conducted in order to ascertain the +most suitable fire-resisting materials for building construction. + +Early in 1904, during the Louisiana Purchase Exposition, Congress made +provision for tests, demonstrations, and investigations concerning the +fuels and structural materials of the United States. These +investigations were organized subsequently as the Technologic Branch of +the United States Geological Survey, under Mr. Joseph A. Holmes, Expert +in Charge, and the President of the United States invited a group of +civilian engineers and Chiefs of Engineering Bureaus of the Government +to act as a National Advisory Board concerning the method of conducting +this work, with a view to making it of more immediate benefit to the +Government and to the people of the United States. This Society is +formally represented on this Board by C. C. Schneider, Past-President, +Am. Soc. C. E., and George S. Webster, M. Am. Soc. C. E. Among +representatives of other engineering societies, or of Government +Bureaus, the membership of the National Advisory Board includes other +members of this Society, as follows: General William Crozier, Frank T. +Chambers, Professor W. K. Hatt, Richard L. Humphrey, Robert W. Hunt, H. +G. Kelley, Robert W. Lesley, John B. Lober, Hunter McDonald, and +Frederick H. Newell. + +In view, therefore, of the important part taken both officially and +unofficially by members of this Society in the planning and organization +of this work, it seems proper to present a statement of the scope, +methods, and progress of these investigations. Whereas the Act governing +this work limits the testing and investigation of fuels and of +structural materials to those belonging to the United States, the +activities of the Federal Government in the use of these materials so +far exceeds that of any other single concern in the United States, that +the results cannot but be of great value to all engineers and to all +those engaged in engineering works. + + +MINE ACCIDENTS INVESTIGATIONS. + +_Organization, and Character of the Work._--The mine rescue +investigations, carried on at the Federal testing station, at Pittsburg, +Pa., include five lines of attack: + +1.--Investigations in the mines to determine the conditions leading up +to mine disasters, the presence and the relative explosibility of mine +gas and coal dust, and mine fires and means of preventing and combating +them. + +2.--Tests to determine the relative safety, or otherwise, of the various +explosives used in coal mining, when ignited in the presence of +explosible mixtures of natural gas and air, or coal dust, or of both. + +3.--Tests to determine the conditions under which electric equipment is +safe in coal-mining operations. + +4.--Tests to determine the safety of various types of mine lights in the +presence of inflammable gas, and their accuracy in detecting small +percentages of mine gas. + +5.--Tests of the various artificial breathing apparatus, and the +training of miners and of skilled mining engineers in rescue methods. + +The first four of these lines of investigation have to do with +preventive measures, and are those on which ultimately the greatest +dependence must be placed. The fifth is one in which the result seems at +first to be the most apparent. It has to do, not with prevention, but +with the cure of conditions which should not arise, or, at least, should +be greatly ameliorated. + +During the last 19 years, 28,514 men have been killed in the coal-mining +industries.[2] In 1907 alone, 3,125 men lost their lives in coal mines, +and, in addition, nearly 800 were killed in the metal mines and quarries +of the country. Including the injured, 8,441 men suffered casualties in +the mines in that year. In every mining camp containing 1,000 men, 4.86 +were taken by violent death in that year. In the mining of coal in Great +Britain, 1.31 men were killed in every 1,000 employed in the same year; +in France, 1.1; in Belgium, 0.94, or less than 1 man in every 1,000 +employed. It is thus seen that from three to four times as many men are +being killed in the United States as in any European coal-producing +country. This safer condition in Europe has resulted from the use of +safer explosives, or the better use of the explosives available; from +the reduction in the use of open lights; from the establishment of mine +rescue stations and the training with artificial breathing apparatus; +and from the adoption of regulations for safeguarding the lives of the +workmen. + +The mining engineering field force of the Geological Survey, at the head +of which is Mr. George S. Rice, an experienced mining and consulting +engineer, has already made great progress in the study of underground +mining conditions and methods. Nearly all the more dangerous coal mines +in the United States have been examined; samples of gas, coal, and dust +have been taken and analyzed at the chemical laboratories at Pittsburg; +extended tests have been made as to the explosibility of various +mixtures of gas and air; as to the explosibility of dust from various +typical coals; as to the chemical composition and physical +characteristics of this dust; the degree of fineness necessary to the +most explosive conditions; and the methods of dampening the dust by +water, by humidifying, by steam, or of deadening its explosibility by +the addition of calcium chloride, stone dust, etc. A bulletin outlining +the results thus far obtained in the study of the coal-dust problem is +now in course of publication.[3] + +After reviewing the history of observations and experiments with coal +dust carried on in Europe, and later, the experiments at the French, +German, Belgian, and English explosives-testing stations, this bulletin +takes up the coal-dust question in the United States. Further chapters +concern the tests as to the explosibility of coal dust, made by the +Geological Survey, at Pittsburg; investigations, both at the Pittsburg +laboratory and in mines, as to the humidity of mine air. There is also a +chapter on the chemical investigations into the ignition of coal dust by +Dr. J. C. W. Frazer, of the Geological Survey. The application of some +of these data to actual mine conditions in Europe, in the last year, is +treated by Mr. Axel Larsen; the use of exhaust steam in a mine of the +Consolidation Coal Company, in West Virginia, is discussed by Mr. Frank +Haas, Consulting Engineer; and the use of sprays in Oklahoma coal mines +is the subject of a chapter by Mr. Carl Scholz, Vice-President of the +Rock Island Coal Mining Company. + +An earlier bulletin setting forth the literature and certain mine +investigations of explosive gases and dust,[4] has already been issued. +After treating of methods of collecting and analyzing the gases found in +mines, of investigations as to the rate of liberation of gas from coal, +and of studies on coal dust, this bulletin discusses such factors as the +restraining influence of shale dust and dampness on coal-dust +explosions. It then takes up practical considerations as to the danger +of explosions, including the relative inflammability of old and fresh +coal dust. The problems involved are undergoing further investigation +and elaboration, in the light of information already gathered. + +_Permissible Explosives._--The most important progress in these tests +and investigations has been made in those relating to the various +explosives used in getting coal from mines. Immediately upon the +enactment of the first legislation, in the spring of 1908, arrangements +were perfected whereby the lower portion of the old Arsenal grounds +belonging to the War Department and adjacent to the Pennsylvania +Railroad, on the Alleghany River, at 40th and Butler Streets, Pittsburg, +Pa., were transferred to the Interior Department for use in these +investigations. Meantime, in anticipation of the appropriation, Mr. +Clarence Hall, an engineer experienced in the manufacture and use of +explosives, was sent to Europe to study the methods of testing +explosives practiced at the Government stations in Great Britain, +Germany, Belgium, and France. Mr. Joseph A. Holmes also visited Europe +for the purpose of studying methods of ameliorating conditions in the +mines. Three foreign mining experts, the chiefs of investigating bureaus +in Belgium, Germany, and England, spent three months studying conditions +in the United States at the invitation of the Secretary of the Interior, +to whom they submitted a valuable report.[5] + +Under the supervision of the writer, Chief Engineer of these +investigations, detailed plans and specifications had been prepared in +advance for the necessary apparatus and the transformation of the +buildings at Pittsburg to the purposes of this work. It was possible, +therefore, to undertake immediately the changes in existing buildings, +the erection of new buildings, the installation of railway tracks, +laboratories, and the plumbing, heating, and lighting plant, etc. This +work was carried on with unusual expedition, under the direction of the +Assistant Chief Engineer, Mr. James C. Roberts, and was completed within +a few months, by which time most of the apparatus was delivered and +installed. + +One building (No. 17) is devoted to the smaller physical tests of +explosives. It was rendered fire resistant by heavily covering the +floors, ceiling, and walls with cement on metal lath, and otherwise +protecting the openings. In it are installed apparatus for determining +calorific value of explosives, pressure produced on ignition, +susceptibility to ignition when dropped, rate of detonation, length and +duration of flame, and kindred factors. Elsewhere on the grounds is a +gallery of boiler-steel plate, 100 ft. long and more than 6 ft. in +diameter, solidly attached to a mass of concrete at one end, in which is +embedded a cannon from which to discharge the explosive under test, and +open at the other end, and otherwise so constructed as to simulate a +small section of a mine gallery (Fig. 2, Plate VI). The heavy mortar +pendulum, for the pendulum test for determining the force produced by an +explosive, is near by, as is also an armored pit in which large +quantities of explosive may be detonated, with a view to studying the +effects of magazine explosions, and for testing as to the rate at which +ignition of an explosive travels from one end to the other of a +cartridge, and the sensitiveness of one cartridge to explosion by +discharge of another near by. + + [Illustration: PLATE VI. + + Fig. 1.--Explosion from Coal Dust in Gas and Dust Gallery No. 1. + + Fig. 2.--Mine Gallery No. 1. + + Fig. 3.--Ballistic Pendulum.] + +In another building (No. 21), is a well-equipped chemical laboratory for +chemical analyses and investigations of explosives, structural +materials, and fuels. + +Several months were required to calibrate the various apparatus, and to +make analyses of the available natural gas to determine the correct +method of proportioning it with air, so as to produce exact mixtures of +2, 4, 6, or 8% of methane with air. Tests of existing explosives were +made in air and in inflammable mixtures of air and gas, with a view to +fixing on some standard explosive as a basis of comparison. Ultimately, +40% nitro-glycerine dynamite was adopted as the standard. Investigative +tests having been made, and the various factors concerning all the +explosives on the market having been determined, a circular was sent to +all manufacturers of explosives in the United States, on January 9th, +1909, and was also published in the various technical journals, through +the associated press, and otherwise. + +On May 15th, 1909, all the explosives which had been offered for test, +as permissible, having been tested, the first list of permissible +explosives was issued, as given in the following circular: + + "EXPLOSIVES CIRCULAR NO. 1. + "DEPARTMENT OF THE INTERIOR. + "United States Geological Survey. + "May 15, 1909. + + "LIST OF PERMISSIBLE EXPLOSIVES. + "Tested prior to May 15, 1909. + + "As a part of the investigation of mine explosions authorized by + Congress in May, 1908, it was decided by the Secretary of the Interior + that a careful examination should be made of the various explosives + used in mining operations, with a view to determining the extent to + which the use of such explosives might be responsible for the + occurrence of these disasters. + + "The preliminary investigation showed the necessity of subjecting to + rigid tests all explosives intended for use in mines where either gas + or dry inflammable dust is present in quantity or under conditions + which are indicative of danger. + + "With this in view, a letter was sent by the Director of the United + States Geological Survey on January 9, 1909, to the manufacturers of + explosives in the United States, setting forth the conditions under + which these explosives would be examined and the nature of the tests + to which they would be subjected. + + "Inasmuch as the conditions and tests described in this letter were + subsequently followed in testing the explosives given in the list + below, they are here reproduced, as follows: + + "(1) The manufacturer is to furnish 100 pounds of each explosive which + he desires to have tested; he is to be responsible for the care, + handling, and delivery of this material at the testing station on the + United States arsenal grounds, Fortieth and Butler streets, Pittsburg, + Pa., at the time the explosive is to be tested; and he is to have a + representative present during the tests, who will be responsible for + the handling of the packages containing the explosives until they are + opened for testing. + + "(2) No one is to be present at or to participate in these tests + except the necessary government officers at the testing station, their + assistants, and the representative of the manufacturer of the + explosives to be tested. + + "(3) The tests will be made in the order of the receipt of the + applications for them, provided the necessary quantity of the + explosive is delivered at the plant by the time assigned, of which due + notice will be given by the Geological Survey. + + "(4) Preference will be given to the testing of explosives that are + now being manufactured and that are in that sense already on the + market. No test will be made of any new explosive which is not now + being manufactured and marketed, until all explosives now on the + market that may be offered for testing have been tested. + + "(5) A list of the explosives which pass certain requirements + satisfactorily will be furnished to the state mine inspectors, and + will be made public in such further manner as may be considered + desirable. + + "TEST REQUIREMENTS FOR EXPLOSIVES. + + "The tests will be made by the engineers of the United States + Explosives Testing Station at Pittsburg, Pa., in gas and dust gallery + No. 1. The charge of explosive to be fired in tests 1, 2, and 3 shall + be equal in disruptive power to one-half pound (227 grams) of 40 per + cent. nitroglycerin dynamite in its original wrapper, of the following + formula: + + Nitroglycerin 40 + Nitrate of sodium 44 + Wood pulp 15 + Calcium carbonate 1 + --- + 100 + + "Each charge shall be fired with an electric fuse of sufficient power + to completely detonate or explode the charge, as recommended by the + manufacturer. The explosive must be in such condition that the + chemical and physical tests do not show any unfavorable results. The + explosives in which the charge used is less than 100 grams (0.22 + pound) will be weighed in tinfoil without the original wrapper. + + "The dust used in tests 2, 3, and 4 will be of the same degree of + fineness and taken from one mine.[6] + + [Footnote 6: With a view to obtaining a dust of uniform purity and + inflammability.] + + "TEST 1.--Ten shots with the charge as described above, in its + original wrapper, shall be fired, each with 1 pound of clay tamping, + at a gallery temperature of 77 F., into a mixture of gas and air + containing 8 per cent. of methane and ethane. An explosive will pass + this test if all ten shots fail to ignite the mixture. + + "TEST 2.--Ten shots with charge as previously noted, in its original + wrapper, shall be fired, each with 1 pound of clay tamping at a + gallery temperature of 77 F., into a mixture of gas and air + containing 4 per cent. of methane and ethane and 20 pounds of + bituminous coal dust, 18 pounds of which is to be placed on shelves + laterally arranged along the first 20 feet of the gallery, and 2 + pounds to be placed near the inlet of the mixing system in such a + manner that all or part of it will be suspended in the first division + of the gallery. An explosive will pass this test if all ten shots fail + to ignite the mixture. + + "TEST 3.--Ten shots with charge as previously noted, in its original + wrapper, shall be fired, each with 1 pound of clay tamping at a + gallery temperature of 77 F., into 40 pounds of bituminous coal dust, + 20 pounds of which is to be distributed uniformly on a horse placed in + front of the cannon and 20 pounds placed on side shelves in sections + 4, 5, and 6. An explosive will pass this test if all ten shots fail to + ignite the mixture. + + "TEST 4.--A limit charge will be determined within 25 grams by firing + charges in their original wrappers, untamped, at a gallery temperature + of 77 F., into a mixture of gas and air containing 4 per cent. of + methane and ethane and 20 pounds of bituminous coal dust, to be + arranged in the same manner as in test 2. This limit charge is to be + repeated five times under the same conditions before being + established. + + "NOTE.--At least 2 pounds of clay tamping will be used with + slow-burning explosives. + + "Washington, D.C., _January 9, 1909_. + + "In response to the above communication applications were received + from 12 manufacturers for the testing of 29 explosives. Of these + explosives, the 17 given in the following list have passed all the + test requirements set forth, and will be termed permissible + explosives. + + _"Permissible explosives tested prior to May 15, 1909._ + + ----------------------------+---------------------------------------- + Brand. | Manufacturer. + ----------------------------+---------------------------------------- + tna coal powder A | tna Powder Co., Chicago, Ill. + tna coal powder B | Do. + Carbonite No. 1 | E. I. Dupont de Nemours Powder Co., + | Wilmington, Del. + Carbonite No. 2 | E. I. Du Pont de Nemours Powder Co., + | Wilmington, Del. + Carbonite No. 3 | Do. + Carbonite No. 1 L. F. | Do. + Carbonite No. 2 L. F. | Do. + Coal special No. 1 | Keystone Powder Co., Emporium, Pa. + Coal special No. 2 | Do. + Coalite No. 1 | Potts Powder Co., New York City. + Coalite No. 2 D | Do. + Collier dynamite No. 2 | Sinnamahoning Powder Co., Emporium, Pa. + Collier dynamite No. 4 | Do. + Collier dynamite No. 5 | Do. + Masurite M. L. F. | Masurite Explosive Co., Sharon, Pa. + Meteor dynamite | E. I. Du Pont de Nemours Powder Co., + | Wilmington, Del. + Monobel | Do. + ----------------------------+---------------------------------------- + + "Subject to the conditions named below, a permissible explosive is + defined as an explosive which has passed gas and dust gallery tests + Nos. 1, 2, and 3 as described above, and of which in test No. 4 1 + pounds (680 grams) of the explosive has been fired into the mixture + there described without causing an ignition. + + "_Provided:_ + + "1. That the explosive is in all respects similar to the sample + submitted by the manufacturer for test. + + "2. That double-strength detonators are used of not less strength than + 1 gram charge consisting by weight of 90 parts of mercury fulminate + and 10 parts of potassium chlorate (or its equivalent), except for the + explosive 'Masurite M. L. F.' for which the detonator shall be of not + less strength than 1 grams charge. + + "3. That the explosive, if in a frozen condition, shall be thoroughly + thawed in a safe and suitable manner before use. + + "4. That the amount used in practice does not exceed 1 pounds (680 + grams) properly tamped. + + "The above partial list includes the permissible explosives that have + passed these tests prior to May 15, 1909. The announcement of the + passing of like tests by other explosives will be made public + immediately after the completion of the tests for such explosives. + + "A description of the method followed in making these and the many + additional tests to which each explosive is subjected, together with + the full data obtained in each case, will be published by the Survey + at an early date. + + "NOTES AND SUGGESTIONS. + + "It may be wise to point out in this connection certain differences + between the permissible explosives as a class and the black powders + now so generally used in coal mining, as follows: + + "(_a_) With equal quantities of each, the flame of the black powder is + more than three times as long and has a duration three thousand to + more than four thousand times that of one of the permissible + explosives, also the rate of explosion is slower. + + "(_b_) The permissible explosives are one and one-fourth to one and + three-fourths times as strong and are said, if properly used, to do + twice the work of black powder in bringing down coal; hence only half + the quantity need be used. + + "(_c_) With 1 pound of a permissible explosive or 2 pounds of black + powder, the quantity of noxious gases given off from a shot averages + approximately the same, the quantity from the black powder being less + than from some of the permissible explosives and slightly greater than + from others. The time elapsing after firing before the miner returns + to the working face or fires another shot should not be less for + permissible explosives than for black powder. + + "The use of permissible explosives should be considered as + supplemental to and not as a substitute for other safety precautions + in mines where gas or inflammable coal dust is present under + conditions indicative of danger. As stated above, they should be used + with strong detonators; and the charge used in practice should not + exceed 1 pounds, and in many cases need not exceed 1 pound. + + "Inasmuch as no explosive manufactured for use in mining is flameless, + and as no such explosive is entirely safe under all the variable + mining conditions, the use of the terms 'flameless' and 'safety' as + applied to explosives is likely to be misunderstood, may endanger + human life, and should be discouraged. + + "JOSEPH A. HOLMES, + "_Expert in Charge Technologic Branch_. + + "Approved, May 18, 1909: + "GEO. OTIS SMITH, + "_Director_." + +In the meantime, many of the explosives submitted, which heretofore had +been on the market as safety explosives, were found to be unsafe for +use in gaseous or dusty mines, and the manufacturers were permitted +to withdraw them. Their weaknesses being known, as a result of these +tests, the manufacturers were enabled to produce similar, but safer, +explosives. Consequently, applications for further tests continued +to pour in, as they still do, and on October 1st, 1909, a second list +of permissible explosives was issued, as follows: + + "EXPLOSIVES CIRCULAR NO. 2. + "DEPARTMENT OF THE INTERIOR. + "United States Geological Survey. + "October 1, 1909. + + "LIST OF PERMISSIBLE EXPLOSIVES. + "Tested prior to October 1, 1909. + + "The following list of permissible explosives tested by the United + States Geological Survey at Pittsburg, Pa., is hereby published for + the benefit of operators, mine owners, mine inspectors, miners, and + others interested. + + "The conditions and test requirements described in Explosives Circular + No. 1, issued under date of May 15, 1909, have been followed in all + subsequent tests. + + "Subject to the provisions named below, a permissible explosive is + defined as an explosive which is in such condition that the chemical + and physical tests do not show any unfavorable results; which has + passed gas and dust gallery tests Nos. 1 and 3, as described in + circular No. 1; and of which, in test No. 4, 1 pounds (680 grams) has + been fired into the mixture there described without causing ignition. + + "_Permissible explosives tested prior to October 1, 1909._ + + "[Those reported in Explosives Circular No. 1 are marked *.] + + ------------------------------+------------------------------------- + Brand. | Manufacturer. + ------------------------------+------------------------------------- + *tna coal powder A | tna Powder Co., Chicago, Ill. + tna coal powder AA | Do. + *tna coal powder B | Do. + tna coal powder C | Do. + Bituminite No. 1 | Jefferson Powder Co., Birmingham, + | Ala. + Black Diamond No. 3 | Illinois Powder Manufacturing Co., + | St. Louis, Mo. + Black Diamond No. 4 | Do. + *Carbonite No. 1 | E. I. Du Pont de Nemours Powder Co., + | Wilmington, Del. + *Carbonite No. 2 | Do. + *Carbonite No. 3 | Do. + *Carbonite No. 1-L. F. | Do. + *Carbonite No. 2-L. F. | Do. + *Coalite No. 1 | Potts Powder Co., New York City. + *Coalite No. 2-D. | Do. + *Coal special No. 1 | Keystone Powder Co., Emporium, Pa. + *Coal special No. 2 | Do. + *Collier dynamite No. 2. | Sinnamahoning Powder Manufacturing + | Co., Emporium, Pa. + *Collier dynamite No. 4. | Do. + *Collier dynamite No. 5. | Do. + Giant A low-flame dynamite. | Giant Powder Co. (Con.), Giant, Cal. + Giant B low-flame dynamite. | Do. + Giant C low-flame dynamite. | Do. + *Masurite M. L. F. | Masurite Explosives Co., Sharon, Pa. + *Meteor dynamite. | E. I. Du Pont de Nemours Powder Co., + | Wilmington, Del. + Mine-ite A. | Burton Powder Co., Pittsburg, Pa. + Mine-ite B. | Do. + *Monobel. | E. I. Du Pont de Nemours Powder Co., + | Wilmington, Del. + Tunnelite No. 5. | G. R. McAbee Powder and Oil Co., + | Pittsburg, Pa. + Tunnelite No. 6. | Do. + Tunnelite No. 7. | Do. + Tunnelite No. 8. | Do. + ------------------------------+------------------------------------- + + "_Provided:_ + + "1. That the explosive is in all respects similar to sample submitted + by the manufacturer for test. + + "2. That No. 6 detonators, preferably No. 6 electric detonators + (double strength), are used of not less strength than 1 gram charge, + consisting by weight of 90 parts of mercury fulminate and 10 parts of + potassium chlorate (or its equivalent), except for the explosive + 'Masurite M. L. F.,' for which the detonator shall be of not less + strength than 1 grams charge. + + "3. That the explosive, if frozen, shall be thoroughly thawed in a + safe and suitable manner before use. + + "4. That the amount used in practice does not exceed 1 pounds (680 + grams), properly tamped. + + "The above partial list includes all the permissible explosives that + have passed these tests prior to October 1, 1909. The announcement of + the passing of like tests by other explosives will be made public + immediately after the completion of the tests. + + "With a view to the wise use of these explosives it may be well in + this connection to point out again certain differences between the + permissible explosives as a class and the black powders now so + generally used in coal mining, as follows: + + "(_a_) With equal quantities of each, the flame of the black powder is + more than three times as long and has a duration three thousand to + more than four thousand times that of one of the permissible + explosives; the rate of explosion also is slower. + + "(_b_) The permissible explosives are one and one-fourth to one and + three-fourths times as strong and are said, if properly used, to do + twice the work of black powder in bringing down coal; hence only half + the quantity need be used. + + "(_c_) With 1 pound of a permissible explosive or 2 pounds of black + powder, the quantity of noxious gases given off from a shot averages + approximately the same, the quantity from the black powder being less + than from some of the permissible explosives and slightly greater than + from others. The time elapsing after firing before the miner returns + to the working face or fires another shot should not be less for + permissible explosives than for black powder. + + "The use of permissible explosives should be considered as + supplemental to and not as a substitute for other safety precautions + in mines where gas or inflammable coal dust is present under + conditions indicating danger. As stated above, they should be used + with strong detonators, and the charge used in practice should not + exceed 1 pounds and in many cases need not exceed 1 pound. + + "JOSEPH A. HOLMES, + "_Expert in Charge Technologic Branch._ + "Approved, October 11, 1909. + "H. C. RIZER, + "_Acting Director._" + +The second list contains 31 explosives which the Government is prepared +to brand as permissible, and therefore comparatively safe, for use in +gaseous and dusty mines. An equally large number of so-called safety +powders failed to pass these tests. Immediately on the passing of the +tests, as to the permissibility of any explosive, the facts are reported +to the manufacturer and to the various State mine inspectors. When +published, the permissible lists were issued to all explosives +manufacturers, all mine operators in the United States, and State +inspectors. The effect has been the enactment, by three of the largest +coal-producing States, of legislation or regulations prohibiting the use +of any but permissible explosives in gaseous or dusty mines, and other +States must soon follow. To prevent fraud, endeavor is being made to +restrict the use of the brand "Permissible Explosive, U.S. Testing +Station, Pittsburg, Pa.," to only such boxes or packages as contain +listed permissible explosives. + +As these tests clearly demonstrate, both in the records thereof and +visually to such as follow them, that certain explosives, especially +those which are slow-burning like black powder, or produce high +temperature in connection with comparative slow burning, will ignite +mixtures of gas and air, or mixtures of coal dust and air, and cause +explosions. The results point out clearly to all concerned, the danger +of using such explosives. The remedy is also made available by the +announcement of the names of a large number of explosives now on the +market at reasonable cost, which will not cause explosions under these +conditions. It is believed that when permissible explosives are +generally adopted in coal mines, this source of danger will have been +greatly minimized. + +_Explosives Investigations._--Questions have arisen on the part of +miners or of mine operators as to the greater cost in using permissible +explosives due to their expense, which is slightly in excess of that of +other explosives; as to their greater shattering effect in breaking down +the coal, and in giving a smaller percentage of lump and a larger +percentage of slack; and as to the possible danger of breathing the +gases produced. + +Observations made in mines by Mr. J. J. Rutledge, an experienced coal +miner and careful mining engineer connected with the Geological Survey, +as to the amount of coal obtained by the use of permissible and other +explosives, tend to indicate that the permissible explosives are not +more, but perhaps less expensive than others, in view of the fact that, +because of their greater relative power, a smaller quantity is required +to do the work than is the case, say, with black powder. On the other +hand, for safety and for certainty of detonation, stronger detonators +are recommended for use with permissible explosives, preferably electric +detonators. These may cost a few cents more per blast than the squib or +fuse, but there is no danger that they will ignite the gas, and the +difference in cost is, in some measure, offset by the greater certainty +of action and the fact that they produce a much more powerful explosion, +thus again permitting the use of still smaller quantities of the +explosive and, consequently, reducing the cost. These investigations are +still in progress. + +Concerning the shattering of the coal: This is being remedied in some of +the permissible explosives by the introduction of dopes, moisture, or +other means of slowing down the disruptive effect, so as to produce the +heaving and breaking effect obtained with the slower-burning powders +instead of the shattering effect produced by dynamite. There is every +reason to believe that as the permissible explosives are perfected, and +as experience develops the proper methods of using them, this difficulty +will be overcome in large measure. This matter is also being +investigated by the Survey mining engineers and others, by the actual +use of such explosives in coal-mining operations. + +Of the gases given off by explosives, those resulting from black powder +are accompanied by considerable odor and smoke, and, consequently, the +miners go back more slowly after the shots, allowing time for the gases +to be dissipated by the ventilation. With the permissible explosive, the +miner, seeing no smoke and observing little odor, is apt to be +incautious, and to think that he may run back immediately. As more is +learned of the use of these explosives, this source of danger, which is, +however, inconsiderable, will be diminished. Table 1 gives the +percentages of the gaseous products of combustions from equal weights of +black powder and two of the permissible explosives. Of the latter, one +represents the maximum amount of injurious gases, and the other the +minimum amount, between which limits the permissible explosives +approximately vary. + +Such noxious gases as may be produced by the discharge of the explosive +are diluted by a much larger volume of air, and are practically +harmless, as proven by actual analysis of samples taken at the face +immediately after a discharge. + + TABLE 1. + + --------+---------+-------------------------- + | | Permissible Explosives. + | Black |-------------+------------ + | powder. | Maximum. | Minimum. + --------+---------+-------------+------------ + CO_{2} | 22.8 | 14.50 | 21.4 + CO | 10.3 | 27.74 | 1.3 + N | 10.3 | 45.09 | 74.4 + --------+---------+-------------+------------ + +In addition to investigations as to explosives for use in coal mining, +the Explosives Section of the Geological Survey analyzes and tests all +such materials, fuses, caps, etc., purchased by the Isthmian Canal +Commission, as well as many other kinds used by the Government. It is +thus acquiring a large fund of useful information, which will be +published from time to time, relative to the kinds of explosives and the +manner of using them best suited to any blasting operations, either +above or under water, in hard rock, earth, or coal. There has been +issued from the press, recently, a primer of explosives,[7] by Mr. +Clarence Hall, the engineer in charge of these tests, and Professor C. +E. Munroe, Consulting Explosives Chemist, which contains a large amount +of valuable fundamental information, so simply expressed as to be easily +understandable by coal miners, and yet sufficiently detailed to be a +valuable guide to all persons who have to handle or use explosives. + +In the first chapters are described the various combustible substances, +and the chemical reactions leading to their explosibility. The low and +high explosives are differentiated, and the sensitiveness of fulminate +of mercury and other detonators is clearly pointed out. The various +explosives, such as gunpowder, black blasting powder, potassium chlorate +powders, nitro-glycerine powders, etc., are described, and their +peculiarities and suitability for different purposes are set forth. The +character and method of using the different explosives, both in opening +up work and in enclosed work in coal mines, follow, with information as +to the proper method of handling, transporting, storing, and thawing the +same. Then follow chapters on squibs, fuses, and detonators; on methods +of shooting coal off the solid; location of bore-holes; undercutting; +and the relative advantages of small and large charges, with +descriptions of proper methods of loading and firing the same. The +subjects of explosives for blasting in rock, firing machines, blasting +machines, and tests thereof, conclude the report. + +The work of the chemical laboratory in which explosives are analyzed, +and in which mine gases and the gases produced by combustion of +explosives and explosions of coal-gas or coal dust are studied, has been +of the most fundamental and important character. The Government is +procuring a confidential record of the chemical composition and mode of +manufacture of all explosives, fuses, etc., which are on the market. +This information cannot but add greatly to the knowledge as to the +chemistry of explosives for use in mines, and will furnish the basis on +which remedial measures may be devised. + +A bulletin (shortly to go to press) which gives the details of the +physical tests of the permissible explosives thus far tested, will set +forth elaborately the character of the testing apparatus, and the method +of use and of computing results.[8] + +This bulletin contains a chapter, by Mr. Rutledge, setting forth in +detail the results of his observations as to the best methods of using +permissible explosives in getting coal from various mines in which they +are used. This information will be most valuable in guiding mining +engineers who desire to adopt the use of permissible explosives, as to +the best methods of handling them. + +_Electricity in Mines._--In connection with the use of electricity in +mines, an informal series of tests has been made on all enclosed +electric fuses, as to whether or not they will ignite an explosive +mixture of air and gas when blown out. The results of this work, which +is under the direction of Mr. H. H. Clark, Electrical Engineer for +Mines, have been furnished the manufacturers for their guidance in +perfecting safer fuses, a series of tests of which has been announced. A +series of tests as to the ability of the insulation of electric wiring +to withstand the attacks of acid mine waters is in progress, which will +lead, it is hoped, to the development of more permanent and cheaper +insulation for use in mine wiring. A series of competitive tests of +enclosed motors for use in mines has been announced, and is in progress, +the object being to determine whether or not sparking from such motors +will cause an explosion in the presence of inflammable gas. + +In the grounds outside of Building No. 10 is a large steel gallery, much +shorter than Gallery No. 1, in fact, but 30 ft. in length, and much +greater in diameter, namely, 10 ft. (Fig. 3, Plate X), in which electric +motors, electric cutting machines, and similar apparatus, are being +tested in the presence of explosive mixtures of gas and dust and with +large amperage and high voltage, such as may be used in the largest +electrical equipment in mines. + +The investigation as to the ability of insulation to withstand the +effects of acid mine waters has been very difficult and complicated. At +first it was believed possible that mine waters from nearby Pennsylvania +mines and of known percentages of acidity could be procured and kept in +an immersion tank at approximately any given percentage of strength. +This was found to be impracticable, as these waters seem to undergo +rapid change the moment they are exposed to the air or are transported, +in addition to the changes wrought by evaporation in the tank. It has +been necessary, therefore, to analyze and study carefully these waters +with a view to reproducing them artificially for the purpose of these +tests. Concerning the insulation, delicate questions have arisen as to a +standard of durability which shall be commensurate with reasonable cost. +These preliminary points are being solved in conference with the +manufacturers, and it is expected that the results will soon permit of +starting the actual tests. + +_Safety-Lamp Investigations._--Many so-called safety lamps are on the +market, and preliminary tests of them have been made in the lamp +gallery, in Building No. 17 (Fig. 2, Plate X). After nearly a year of +endeavor to calibrate this gallery, and to co-ordinate its results with +those produced in similar galleries in Europe, this preliminary inquiry +has been completed, and the manufacturers and agents of all safety lamps +have been invited to be present at tests of their products at the +Pittsburg laboratory. + +A circular dated November 19th, 1909, contains an outline of these +tests, which are to be conducted under the direction of Mr. J. W. Paul, +an experienced coal-mining engineer and ex-Chief of the Department of +State Mine Inspection of West Virginia. The lamps will be subjected to +the following tests: + +(_a_).--Each lamp will be placed in a mixture of air and explosive +natural gas containing 6, 8, and 10% of gas, moving at a velocity of +from 200 to 2,500 ft. per min., to determine the velocity of the air +current which will ignite the mixture surrounding the lamp. The current +will be made to move against the lamp in a horizontal, vertical +ascending, and vertical descending direction, and at an angle of 45, +ascending and descending. + +(_b_).--After completing the tests herein described, the lamps will be +subjected to the tests described under (_a_), with the air and gas +mixture under pressure up to 6 in. of water column. + +(_c_).--Under the conditions outlined in (_a_), coal dust will be +introduced into the current of air and gas to determine its effect, if +any, in inducing the ignition of the gas mixture. + +(_d_).--Each lamp will be placed in a mixture of air and varying +percentages of explosive natural gas to determine the action of the gas +on the flame of the lamp. + +(_e_).--Each lamp will be placed in a mixture of air and varying +percentages of carbonic acid gas to determine the action of the gas on +the flame. + +(_f_).--Lamps equipped with internal igniters will be placed in +explosive mixtures of air and gas in a quiet state and in a moving +current, and the effect of the igniter on the surrounding mixture will +be observed. + +(_g_).--The oils (illuminants) used in the lamps will be tested as to +viscosity, gravity, flashing point, congealing point, and composition. + +(_h_).--Safety-lamp globes will be tested by placing each globe in +position in the lamp and allowing the flame to impinge against the globe +for 3 min. after the lamp has been burning with a full flame for 10 +min., to determine whether the globe will break. + +(_i_).--Each safety-lamp globe will be mounted in a lighted lamp with +up-feed, and placed for 5 min. in an explosive mixture of air and gas +moving at the rate of 1,000 ft. per min., to determine whether the heat +will break the glass and, if it is broken, to note the character of the +fracture. + +(_j_).--Safety-lamp globes will be broken by impact, by allowing each +globe to fall and strike, horizontally, on a block of seasoned white +oak, the distance of fall being recorded. + +(_k_).--Each safety lamp globe will be mounted in a safety lamp and, +when the lamp is in a horizontal position, a steel pick weighing 100 +grammes will be permitted to fall a sufficient distance to break the +globe by striking its center, the distance of the fall to be recorded. + +(_l_).--To determine the candle power of safety lamps, a photometer +equipped with a standardized lamp will be used. The candle-power will be +determined along a line at right angles to the axis of the flame; also +along lines at angles to the axis of the flame both above and below the +horizontal. The candle-power will be read after the lamp has been +burning 20 min. + +(_m_).--The time a safety lamp will continue to burn with a full charge +of illuminant will be determined. + +(_n_).--Wicks in lamps must be of sufficient length to be at all times +in contact with the bottom of the vessel in which the illuminant is +contained, and, before it is used, the wick shall be dried to remove +moisture. + +_Mine-Rescue Methods._--Mr. Paul, who has had perhaps as wide an +experience as any mining man in the investigation of and in rescue work +at mine disasters, is also in charge of the mine-rescue apparatus and +training for the Geological Survey. These operations consist chiefly of +a thorough test of the various artificial breathing apparatus, or +so-called oxygen helmets. Most of these are of European make and find +favor in Great Britain, Belgium, France, or Germany, largely according +as they are of domestic design and manufacture. As yet nothing has been +produced in the United States which fulfills all the requirements of a +thoroughly efficient and safe breathing apparatus for use in mine +disasters. + +At the Pittsburg testing station there are a number of all kinds of +apparatus. The tests of these are to determine ease of use, of repair, +durability, safety under all conditions, period during which the supply +of artificial air or oxygen can be relied on, and other essential data. + +In addition to the central testing station, sub-stations for training +miners, and as headquarters for field investigation as to the causes of +mine disasters and for rescue work in the more dangerous coal fields, +have been established; at Urbana, Ill., in charge of Mr. R. Y. Williams, +Mining Engineer; at Knoxville, Tenn., in charge of Mr. J. J. Rutledge, +Mining Engineer; at McAlester, Okla., in charge of Mr. L. M. Jones, +Assistant Mining Engineer; and at Seattle, Wash., in charge of Mr. Hugh +Wolflin, Assistant Mining Engineer. Others may soon be established in +Colorado and elsewhere, in charge of skilled mining engineers who have +been trained in this work at Pittsburg, and who will be assisted by +trained miners. It is not to be expected that under any but +extraordinary circumstances, such as those which occurred at Cherry, +Ill., the few Government engineers, located at widely scattered points +throughout the United States, can hope to save the lives of miners after +a disaster occurs. As a rule, all who are alive in the mine on such an +occasion, are killed within a few hours. This is almost invariably the +case after a dust explosion, and is likely to be true after a gas +explosion, although a fire such as that at Cherry, Ill., offers the +greatest opportunity for subsequent successful rescue operations. The +most to be hoped for from the Government engineers is that they shall +train miners and be available to assist and advise State inspectors and +mine owners, should their services be called for. + +It should be borne in mind that the Federal Government has no police +duties in the States, and that, therefore, its employees may not direct +operations or have other responsible charge in the enforcement of State +laws. There is little reason to doubt that these Federal mining +engineers, both because of their preliminary education as mining +engineers and their subsequent training in charge of mine operations, +and more recently in mine-accidents investigations and rescue work, are +eminently fitted to furnish advice and assistance on such occasions. The +mere fact that, within a year, some of these men have been present at, +and assisted in, rescue work or in opening up after disasters at nearly +twenty of such catastrophes, whereas the average mining engineer or +superintendent may be connected with but one in a lifetime, should make +their advice and assistance of supreme value on such occasions. They +cannot be held in any way responsible for tardiness, however, nor be +unduly credited with effective measures taken after a mine disaster, +because of their lack of responsible authority or charge, except in +occasional instances where such may be given them by the mine owners or +the State officials, from a reliance on their superior equipment for +such work. + +Successful rescue operations may only be looked for when the time, now +believed to be not far distant, has been reached when the mine operators +throughout the various fields will have their own rescue stations, as is +the practice in Europe, and have available, at certain strategic mines, +the necessary artificial breathing apparatus, and have in their employ +skilled miners who have been trained in rescue work at the Government +stations. Then, on the occurrence of a disaster, the engineer in charge +of the Government station may advise by wire all those who have proper +equipment or training to assemble, and it may be possible to gather, +within an hour or two of a disaster, a sufficiently large corps of +helmet-men to enable them to recover such persons as have not been +killed before the fire--which usually is started by the explosion--has +gained sufficient headway to prevent entrance into the mine. Without +such apparatus, it is essential that the fans be started, and the mine +cleared of gas. The usual effect of this is to give life to any +incipient fire. With the apparatus, the more dense the gas, the safer +the helmet-men are from a secondary explosion or from the rapid ignition +of a fire, because of the absence of the oxygen necessary to combustion. + +The miners who were saved at Cherry, Ill., on November 20th, 1909, owe +their lives primarily to the work of the Government engineers. The +sub-station of the Survey at Urbana, Ill., was promptly notified of the +disaster on the afternoon of November 13th. Arrangements were +immediately made, whereby Mr. R. Y. Williams, Mining Engineer in Charge, +and his Assistant, Mr. J. M. Webb, with their apparatus, were rushed by +special train to the scene, arriving early the following day (Sunday). + +Chief Mining Engineer, George S. Rice, Chief of Rescue Division, J. W. +Paul, and Assistant Engineer, F. F. Morris, learned of the disaster +through the daily press, at their homes in Pittsburg, on Sunday. They +left immediately with four sets of rescue apparatus, reaching Cherry on +Monday morning. Meantime, Messrs. Williams and Webb, equipped with +oxygen helmets, had made two trips into the shaft, but were driven out +by the heat. Both shafts were shortly resealed with a view to combating +the fire, which had now made considerable headway. + +The direction of the operations at Cherry, was, by right of +jurisdiction, in charge of the State Mine Inspectors of Illinois, at +whose solicitation the Government engineers were brought into conference +as to the proper means to follow in an effort to get into the mine. The +disaster was not due to an explosion of coal or gas, but was the result +of a fire ignited in hay, in the stable within the mine. The flame had +come through the top of the air-shaft, and had disabled the ventilating +fans. A rescue corps of twelve men, unprotected by artificial breathing +apparatus, had entered the mine, and all had been killed. When the +shafts were resealed on Monday evening, the 15th, a small hole was left +for the insertion of a water-pipe or hose. During the afternoon and +evening, a sprinkler was rigged up, and, by Tuesday morning, was in +successful operation, the temperature in the shaft at that time being +109 Fahr. After the temperature had been reduced to about 100, the +Federal engineers volunteered to descend into the shaft and make an +exploration. The rescue party, consisting of Messrs. Rice, Paul, and +Williams, equipped with artificial breathing apparatus, made an +exploration near the bottom of the air-shaft and located the first body. +After they had returned to the surface, three of the Illinois State +Inspectors, who had previously received training by the Government +engineers in the use of the rescue apparatus, including Inspectors Moses +and Taylor, descended, made tests of the air, and found that with the +fan running slowly, it was possible to work in the shaft. The rescue +corps then took hose down the main shaft, having first attached it to a +fire engine belonging to the Chicago Fire Department. Water was directed +on the fire at the bottom of the shaft, greatly diminishing its force, +and it was soon subdued sufficiently to permit the firemen to enter the +mine without the protection of breathing apparatus. + +Unfortunately, these operations could be pursued only under the most +disadvantageous circumstances and surrounded by the greatest possible +precautions, due to the frequent heavy falls of roof--a result of the +heating by the mine fire--and the presence of large quantities of +black-damp. All movements of unprotected rescuers had to be preceded by +exploration by the trained rescue corps, who analyzed the gases, as the +fire still continued to burn, and watched closely for falls, possible +explosions, or a revival of the fire. While the heavy work of shoring +up, and removing bodies, was being carried on by the unprotected rescue +force, the helmet-men explored the more distant parts of the mine, and +on Saturday afternoon, November 20th, one week after the disaster, a +room was discovered in which a number of miners, with great presence of +mind, had walled themselves in in order to keep out the smoke and heat. +From this room 20 living men were taken, of whom 12 were recovered in a +helpless condition, by the helmet-men. + +This is not the first time this Government mining corps has performed +valiant services. Directly and indirectly the members have saved from +fifteen to twenty lives in the short time they have been organized. At +the Marianna, Pa., disaster, the corps found one man still alive among +150 bodies, and he was brought to the surface. He recovered entirely +after a month in the hospital. + +At the Leiter mine, at Zeigler, Ill., two employees, who had been +trained in the use of the oxygen helmets by members of the Government's +corps, went down into the mine, following an explosion, and brought one +man to the surface, where they resuscitated him. + +Equally good service, either in actual rescue operations, or in +explorations after mine disasters, or in fire-fighting, has been +rendered by this force at the Darr, Star Junction, Hazel, Clarinda, +Sewickley, Berwind-White No. 37, and Wehrum, Pa., mine disasters; at +Monongah and Lick Branch, W. Va.; at Deering, Sunnyside, and Shelburn, +Ind., Jobs, Ohio, and at Roslyn, Wash. + +_Explosives Laboratory._--The rooms grouped at the south end of Building +No. 21, at Pittsburg, are occupied as a laboratory for the chemical +examination and analysis of explosives, and are in charge of Mr. W. O. +Snelling. + +Samples of all explosives used in the testing gallery, ballistic +pendulum, pressure gauge, and other testing apparatus, are here +subjected to chemical analysis in order to determine the component +materials and their exact percentages. Tests are also made to determine +the stability of the explosive, or its liability to decompose at various +temperatures, and other properties which are of importance in showing +the factors which will control the safety of the explosive during +transportation and storage. + +In the investigation of all explosives, the first procedure is a +qualitative examination to determine what constituents are present. +Owing to the large number of organic and inorganic compounds which enter +into the composition of explosive mixtures, this examination must be +thorough. Several hundred chemical bodies have been used in explosives +at different times, and some of these materials can be separated from +others with which they are mixed only by the most careful and exact +methods of chemical analysis. + +Following the qualitative examination, a method is selected for the +separation and weighing of each of the constituents previously found to +be present. These methods, of course, vary widely, according to the +particular materials to be separated, it being usually necessary to +devise a special method of analysis for each explosive, unless it is +found, by the qualitative analysis, to be similar to some ordinary +explosive, in which case the ordinary method of analysis of that +explosive can be carried out. Most safety powders require special +treatment, while most grades of dynamite and all ordinary forms of black +blasting powder are readily analyzed by the usual methods. + +The examination of black blasting powder has been greatly facilitated +and, at the same time, made considerably more accurate, by means of a +densimeter devised at this laboratory. In this apparatus a Torricellian +vacuum is used as a means of displacing the air surrounding the grains +of powder, and through very simple manipulation the true density of +black powder is determined with a high degree of accuracy. In Building +No. 17 there is an apparatus for separating or grading the sizes of +black powder (Fig. 1, Plate X). + +By means of two factors, the moisture coefficient and the hygroscopic +coefficient, which have been worked out at this laboratory, a number of +important observations can be made on black powder, in determining the +relative efficiency of the graphite coating to resist moisture, and also +as a means of judging the thoroughness with which the components of the +powder are mixed. The moisture coefficient relates to the amount of +moisture which is taken up by the grains of the powder in a definite +time under standard conditions of saturation; and the hygroscopic +coefficient relates to the affinity of the constituents of the powder +for moisture under the same standard conditions. + +Besides the examination of explosives used at the testing station, those +for the Reclamation Service, the Isthmian Canal Commission, and other +divisions of the Government, are also inspected and analyzed at the +explosives laboratory. At the present time, the Isthmian Canal +Commission is probably the largest user of explosives in the world, and +samples used in its work are inspected, tested, and analyzed at this +laboratory, and at the branch laboratories at Gibbstown and Pompton +Lakes, N.J., and at Xenia, Ohio. + +Aside from the usual analysis of explosives for the Isthmian Canal +Commission, special tests are made to determine the liability of the +explosive to exude nitro-glycerine, and to deteriorate in unfavorable +weather conditions. These tests are necessary, because of the warm and +moist climate of the Isthmus of Panama. + +_Gas and Dust Gallery No. 1._--Gallery No. 1 is cylindrical in form, 100 +ft. long, and has a minimum internal diameter of 6-1/3 ft. It consists +of fifteen similar sections, each 6-2/3 ft. long and built up in +in-and-out courses. The first three sections, those nearest the concrete +head, are of -in. boiler-plate steel, the remaining twelve sections are +of 3/8-in. boiler-plate steel, and have a tensile strength of, at least, +55,000 lb. per sq. in. Each section has one release pressure door, +centrally placed on top, equipped with a rubber bumper to prevent its +destruction when opened quickly. In use, this door may be either closed +and unfastened, closed and fastened by stud-bolts, or left open. Each +section is also equipped with one -in. plate-glass window, 6 by 6 in., +centrally placed in the side of the gallery (Fig. 1, and Figs. 1 and 2, +Plate VI). The sections are held together by a lap-joint. At each +lap-joint there is, on the interior of the gallery, a 2-in. circular, +angle iron, on the face of which a paper diaphragm may be placed and +held in position by semicircular washers, studs, and wedges. These paper +diaphragms are used to assist in confining a gas-and-air mixture. + + [Illustration: Fig. 1. + + EXPLOSIVES TESTING GALLERY No. 1] + +Natural gas from the mains of the City of Pittsburg is used to represent +that found in the mines by actual analysis. A typical analysis of this +gas is as follows: + +Volumetric Analysis of Typical Natural Gas. + + Hydrogen gases 0 + Carbon dioxide 0.1 + Oxygen 0 + Heavy hydrocarbons 0 + Carbon monoxide 0 + Methane 81.8 + Ethane 16.8 + Nitrogen 1.3 + +The volume of gas used is measured by an accurate test meter reading to +one-twentieth of a cubic foot. The required amount is admitted near the +bottom, to one or more of the 20-ft. divisions of the gallery, from a +2-in. pipe, 14 ft. long. The pipe has perforations arranged so that an +equal flow of gas is maintained from each unit length. + +Each 20-ft. division of the gallery is further equipped with an exterior +circulating system, as shown by Fig. 1, thus providing an efficient +method of mixing the gas with the air. For the first division this +circulating system is stationary, a portion of the piping being equipped +with heating coils for maintaining a constant temperature. + +The other divisions have a common circulating system mounted on a truck +which may be used on any of these divisions. Valves are provided for +isolating the fan so that a possible explosion will not injure it. + +In the center section of each division is an indicator cock which is +used to provide means of recording pressures above and below +atmospheric, or of sampling the air-and-gas mixture. The first division +of the gallery is equipped with shelves laterally placed, for the +support of coal dust. + +The cannon in which the explosive is fired is placed in the concrete +head, the axial line of the bore-hole being coincident with that of the +gallery. This cannon (Fig. 2) is similar to that used in the ballistic +pendulum. The charge is fired electrically from the observation room. To +minimize the risk of loading the cannon, the charger carries in his +pocket the plug of a stage switch (the only plug of its kind on the +ground), so that it is impossible to complete the circuit until the +charger has left the gallery. That portion of the first division of the +gallery which is not embedded in concrete, has a 3-in. covering made up +of blocks of magnesia, asbestos fiber, asbestos, cement, a thin layer of +8-oz. duck, and strips of water-proof roofing paper, the whole being +covered with a thick coat of graphite paint. The object of this covering +is to assist in maintaining a constant temperature. + + [Illustration: PLATE VII. + + Fig. 1.--Bichel Pressure Gauges. + + Fig. 2.--Rate of Detonation Recorder.] + +The entire gallery rests on a concrete foundation 10 ft. wide, which has +a maximum height of 4 ft. and a minimum height of 2 ft. + +The concrete head in which the cannon is placed completely closes that +end of the gallery. A narrow drain extends under the entire length of +the gallery, and a tapped hole at the bottom of each section provides an +efficient means of drainage. + + [Illustration: Fig. 2. + + {cannon as described in text} ] + +The buildings near the gallery are protected by two barricades near the +open end, each 10 ft. high and 30 ft. long. A back-stop, consisting of a +swinging steel plate, 6 ft. high and 9 ft. long, 50 ft. from the end of +the gallery, prevents any of the stemming from doing damage. + +Tests are witnessed from an observation room, a protected position about +60 ft. from the gallery. The walls of the room are 18 in. thick, and the +line of vision passes through a -in. plate glass, 6 in. wide and 37 ft. +long, and is further confined by two external guards, each 37 ft. long +and 3 ft. wide. + +In this gallery a series of experiments has been undertaken to determine +the amount of moisture necessary with different coal dusts, in order to +reduce the likelihood of a coal-dust explosion from a blown-out shot of +one of the dangerous types of explosives. + +Coal dust taken from the roads of one of the coal mines in the Pittsburg +district required at least 12% of water to prevent an ignition. It has +also been proven that the finer the dust the more water is required, and +when it was 100-mesh fine, 30% of water was required to prevent its +ignition by the flame of a blown-out shot in direct contact. The methods +now used in sprinkling have been proven entirely insufficient for +thoroughly moistening the dust, and hence are unreliable in preventing a +general dust explosion. + +At this station successful experiments have been carried out by using +humidifiers to moisten the atmosphere after the temperature of the air +outside the gallery has been raised to mine temperature and drawn +through the humidifiers. It has been found that if a relative humidity +of 90%, at a temperature of 60 Fahr., is maintained for 48 hours, +simulating summer conditions in a mine, the absorption of moisture by +the dust and the blanketing effect of the humid air prevent the general +ignition of the dust. + +These humidity tests have been run in Gas and Dust Gallery No. 1 with +special equipment consisting of a Koerting exhauster having a capacity +of 240,000 cu. ft. per hour, which draws the air out of the gallery +through the first doorway, or that next the concrete head in which the +cannon is embedded. + +The other end of the gallery is closed by means of brattice cloth and +paper diaphragms, the entire gallery being made practically air-tight. +The air enters the fifteenth doorway through a box, passing over steam +radiators to increase its temperature, and then through the humidifier +heads. + + +EXPLOSIVES TESTING APPARATUS. + +There is no exposed woodwork in Building No. 17, which is 40 by 60 ft., +two stories high, and substantially constructed of heavy stone masonry, +with a slate roof. The structure within is entirely fire-proof. Iron +columns and girders, and wooden girders heavily encased in cement, +support the floors which are either of cement slab construction or of +wooden flooring protected by expanded metal and cement mortar, both +above and beneath. At one end, on the ground floor, is the exposing and +recording apparatus for flame tests of explosives, also pressure gauges, +and a calorimeter, and, at the other end, is a gallery for testing +safety lamps. + +The larger portion of the second floor is occupied by a gas-tight +training room for rescue work, and an audience chamber, from which +persons interested in such work may observe the methods of procedure. A +storage room for rescue apparatus and different models of safety lamps +is also on this floor. + +The disruptive force of explosives is determined in three ways, namely, +by the ballistic pendulum, by the Bichel pressure gauge, and by Trauzl +lead blocks. + +_Ballistic Pendulum._--The disruptive force of explosives, as tested by +the ballistic pendulum, is measured by the amount of oscillation. The +standard unit of comparison is a charge of lb. of 40% nitro-glycerine +dynamite. The apparatus consists essentially of a 12-in. mortar (Fig. 3, +Plate VI), weighing 31,600 lb., and suspended as a pendulum from a beam +having knife-edges. A steel cannon is mounted on a truck set on a track +laid in line with the direction of the swing of the mortar. At the time +of firing the cannon may be placed 1/16-in. from the muzzle of the +mortar. The beam, from which the mortar is suspended, rests on concrete +walls, 51 by 120 in. at the base and 139 in. high. On top of each wall +is a 1-in. base-plate, 7 by 48 in., anchored to the wall by 5/8-in. +bolts, 28 in. long. The knife-edges rest on bearing-plates placed on +these base-plates. The bearing-plates are provided with small grooves +for the purpose of keeping the knife-edges in oil and protected from the +weather. The knife-edges are each 6 in. long, 2-11/16 in. deep from +point to back, 2 in. wide at the back, and taper 50 with the +horizontal, starting on a line 1 in. from the back. The point is +rounded to conform to a radius of in. The back of each is 2 in. longer +than the edge, making a total length of 10 in., and is 1 in. deep and 12 +in. wide. This shoulder gives bolting surface to the beam from which the +mortar is hung. The beam is of solid steel, has a 4 by 8-in. section, +and is 87 in. long. Heavy steel castings are bolted to it to take the +threads of the machine-steel rods which form the saddles on which the +mortar is suspended. The radius of the swing, measured from the point of +the knife-edges to the center of the trunnions, is 89 in. + +The cannon consists of two parts, a jacket and a liner. The jacket is 36 +in. long, has an external diameter of 24 in., and internal diameters of +9 and 7 in. It is made of the best cast steel or of forged steel. + +The liner is 36 in. long, with a 1-in. shoulder, 7 in. from the back, +changing the diameter from 9 to 7 in. The bore is smooth, being 2 in. +in diameter and 21 in. long. The cannon rests on a 4-wheel truck, to +which it is well braced by straps and rods. A track of 30-in. gauge +extends about 9 ft. from the muzzle of the mortar to the bumper for the +cannon. + +The shot is fired by an electric firing battery, from the first floor of +Building No. 17, about 10 yd. away. To insure the safety of the operator +and the charger, the man who loads the cannon carries a safety plug +without which the charge cannot be exploded. The wires for connecting to +the fuse after charging are placed conveniently, and the safety plug is +then inserted in a box at the end of the west wall. The completion of +the firing battery by the switch at the firing place is indicated by the +flashing of a red light, after which all that is necessary to set off +the charge is to press a button on the battery. An automatic recording +device at the back of the mortar records the length of swing which, by a +vernier, may be read to 1/200 in. + +_Bichel Pressure Gauges._--Pressure gauges are constructed for the +purpose of determining the unit disruptive force of explosives +detonating at different rates of velocity, by measuring pressures +developed in an enclosed space from which the generated gases cannot +escape. The apparatus consists of a stout steel cylinder, which may be +made absolutely air-tight; an air-pump and proper connections for +exhausting the air in the cylinder to a pressure equivalent to 10 mm. of +mercury; an insulated plug for providing the means of igniting the +charge; a valve by which the gaseous products of combustion may be +removed for subsequent analysis; and an indicator drum (Fig. 1, Plate +VII) with proper connections for driving it at a determinable speed. + +This apparatus is in the southeast corner of Building No. 17. The +cylinder is 31 in. long, 19 in. in diameter, and is anchored to a +solid concrete footing at a convenient height for handling. The +explosion chamber is 19 in. long and 7-7/8 in. in diameter, with a +capacity of exactly 15 liters. The cover of the cylinder is a heavy +piece of steel held in place by stout screw-bolts and a heavy steel +clamp. + +The charge is placed on a small wire tripod, and connections are made +with a fuse to an electric firing battery for igniting the charges. The +cover is drawn tight, with the twelve heavy bolts against lead washers. +The air in the cylinder is exhausted to 10 mm., mercury column, in order +to approach more closely the conditions of a stemmed charge exploding in +a bore-hole inaccessible to air; the indicator drum is placed in +position and set in motion; and, finally, the shot is fired. The record +shown on the indicator card is a rapidly ascending curve for quick +explosives and a shallower, slowly rising curve for explosives of slow +detonation. When the gases cool, the curve merges into a straight line, +which indicates the pressures of the cooled gases on the sides of the +chamber. + + [Illustration: PLATE VIII. + + Fig. 1.--Explosives Calorimeter. + + Fig. 2.--Building No. 17, and Flame-Test Apparatus. + + Fig. 3.--Small Lead Block Test.] + +Since the ratio of the volume of the cylinder to the volume of the +charge may be computed, the pressure of the confined charge may also be +found, and this pressure often exceeds 100,000 lb. per sq. in. The +cooling effect of the inner surface on the gaseous products of +combustion, a vital point in computations of the disruptive force of +explosives by this method, is determined by comparing the pressures +obtained in the original cylinder with those in a second cylinder of +larger capacity, into which has been inserted one or more steel +cylinders to increase the superficial area while keeping the volume +equal to that of the first cylinders. By comparing results, a curve may +be plotted, which will determine the actual pressures developed, with +the surface-cooling effect eliminated. + +_Trauzl Lead Blocks._--The lead-block test is the method adopted by the +Fifth International Congress of Applied Chemistry as the standard for +measuring the disruptive force of explosives. The unit by this test is +defined to be the force required to enlarge the bore-hole in the block +to an amount equivalent to that produced by 10 grammes of standard 40% +nitro-glycerine dynamite stemmed with 50 grammes of dry sand under +standard conditions as produced with the tamping device. The results of +this test, when compared with those of the Bichel gauge, indicate that, +for explosives of high detonation, the lead block is quite accurate, but +for slow explosives, such as gunpowder, the expansion of the gases is +not fast enough to make comparative results of value. The reason for +this is that the gases escape through the bore of the block rather than +take effect in expanding the bore-hole. + +The lead blocks are cylindrical, 200 mm. in diameter, and 200 mm. high. +Each has a central cavity, 25 mm. in diameter and 125 mm. deep (Fig. 1, +Plate IX), in which the charge is placed. The blocks are made of +desilverized lead of the best quality, and, as nearly as possible, under +identical conditions. The charge is placed in the cavity and prepared +for detonation with an electrical exploder and stemming. After the +explosion the bore-hole is pear-shaped, the size of the cavity +depending, not only on the disruptive power of the explosive, but also +on its rate of detonation, as already indicated. The size of the +bore-hole is measured by filling the cavity with water from a burette. +The difference in the capacity of the cavity before and after detonation +indicates the enlarging power of the explosive. + +_Calorimeter._--The explosion calorimeter is designed to measure the +amount of heat given off by the detonation of explosive charges of 100 +grammes. The apparatus consists of the calorimeter bomb (Fig. 1, Plate +VIII), the inner receiver or immersion vessel, a wooden tub, a +registering thermometer, and a rocking frame. This piece of apparatus +stands on the east side of Building No. 17. + +The bottle-shaped bomb is made of -in. wrought steel, and has a +capacity of 30 liters. On opposite sides near the top are bored +apertures, one for the exhaust valve for obtaining a partial vacuum +(about 20 mm., mercury column) after the bomb has been charged, the +other for inserting the plug through which passes the fuse wire for +igniting the charge. The bomb is closed with a cap, by which the chamber +may be made absolutely air-tight. It is 30 in. high with the cap on, +weighs 158 lb., and is handled to and from the immersion vessel by a +small crane. + +The inner receiver is made of 1/16-in. sheet copper, 30-7/8 in. deep, +and with an inner diameter of 17-7/8 in. It is nickel-plated, and +strengthened on the outside with bands of copper wire, and its capacity +is about 70 liters. The outer tub is made of 1-in. lumber strengthened +with four brass hoops on the outside. It is 33 in. deep, and its inner +diameter is 21 in. + +The stirring device, operated vertically by an electric motor, consists +of a small wooden beam connected to a system of three rings having a +horizontal bearing surface. When the apparatus is put together, the +inner receiver rests on a small standard on top of the base of the outer +tank, and the rings of the stirring device are run between the bomb and +the inner receiver. The bomb itself rests on a small standard placed on +the bottom of the inner receiver. The apparatus is provided with a +snugly fitting board cover. The bomb is charged from the top, the +explosive being suspended in its center. The air is exhausted to the +desired degree of rarification. The caps are then screwed on, and the +apparatus is set together as described. + + [Illustration: PLATE IX. + + Fig. 1.--Trauzl Lead Blocks. + + Fig. 2.--Powder Flames.] + +The apparatus is assembled on scales and weighed before the water is +poured in and after the receiver is filled. From the weight of the water +thus obtained and the rise of temperature, the calorific value may be +computed. The charge is exploded by electricity, while the water is +being stirred. The rise in the temperature of the water is read by a +magnifying glass, from a thermometer which measures temperature +differences of 0.01 degree. From the readings obtained, the maximum +temperature of explosion may be determined, according to certain +formulas for calorimetric experiments. Proper corrections are made for +the effects, on the temperature readings, of the formation of the +products of combustion, and for the heat-absorbing power of the +apparatus. + +_Impact Machine._--In Building No. 17, at the south side, is an impact +machine designed to gauge the sensitiveness of explosives to shock. For +this purpose, a drop-hammer, constructed to meet the following +requirements, is used: A substantial, unyielding foundation; minimum +friction in the guide-grooves; and no escape or scattering of the +explosive when struck by the falling weight. This machine is modeled +after one used in Germany, but is much improved in details of +construction. + +The apparatus, Fig. 1, Plate XI, consists essentially of the following +parts: An endless chain working in a vertical path and provided with +lugs; a steel anvil on which the charge of explosive is held by a steel +stamp; a demagnetizing collar moving freely in vertical guides and +provided with jaws placed so that the lugs of the chain may engage them; +a steel weight sliding loosely in vertical guides and drawn by the +demagnetizing collar to determinable heights when the machine is in +operation; a second demagnetizing collar, which may be set at known +heights, and provided with a release for the jaws of the first collar; +and a recording device geared to a vertically-driven threaded rod which +raises or lowers, sets the second demagnetizing collar, and thus +determines the height of fall of the weight. By this apparatus the +weight may be lifted to different known heights, and dropped on the +steel stamp which transmits the shock to the explosive. The fall +necessary to explode the sample is thus determined. + +The hammers are of varying weight, the one generally used weighing +2,000 grammes. As the sensitiveness of an explosive is influenced by +temperature changes, water at 25 cent. is allowed to flow through the +anvil in order to keep its temperature uniform. + +_Flame Test._--An apparatus, Fig. 2, Plate VIII, designed to measure +the length and duration of flames given off by explosives, is placed at +the northeast corner of Building No. 17. It consists essentially of a +cannon, a photographing device, and a drum geared for high speed, to +which a sensitized film may be attached. + +About 13 ft. outside the wall of Building No. 17, set in a concrete +footing, is a cannon pointing vertically into an encasing cylinder or +stack, 20 ft. high and 43 in. in diameter. This cannon is a duplicate of +the one used for the ballistic pendulum, details of which have already +been given. The stack or cylinder is of -in. boiler plate, in +twenty-four sections, and is absolutely tight against light at the base +and on the sides. It is connected with a dark room in Building No. 17 by +a light-tight conduit of rectangular section, 12 in. wide, horizontal on +the bottom, and sloping on the top from a height of 8 ft. at the stack +to 21 in. at the inside of the wall of the building. + +The conduit is carefully insulated from the light at all joints, and is +riveted to the stack. A vertical slit, 2 in. wide and 8 ft. long, +coincident with the center line of the conduit, is cut in the stack. A +vertical plane drawn through the center line of the bore-hole of the +cannon and that of the slit, if produced, intersects the center line of +a quartz lens, and coincides with the center of a stenopaic slit and the +axis of the revolving drum carrying the film. The photographing +apparatus consists of a shutter, a quartz lens, and a stenopaic slit, 76 +by 1.7 mm., between the lens and the sensitized film on the rotary drum. +The quartz lens is used because it will focus the ultra-violet rays, +which are those attending extreme heat. + +The drum is 50 cm. in circumference and 10 cm. deep. It is driven by a +220-volt motor connected to a tachometer which reads both meters per +second and revolutions per minute. A maximum peripheral speed of 20 m. +per sec. may be obtained. + +When the cannon is charged, the operator retires to the dark room in +which the recording apparatus is located, starts the drum, obtains the +desired speed, and fires the shot by means of a battery. When developed, +the film shows a blur of certain dimensions, produced by the flame from +the charge. From the two dimensions--height and lateral +displacement--the length and duration of the flame of the explosive are +determined. + +The results of flame tests of a permissible explosive and a test of +black blasting powder, all shot without stemming, are shown on Fig. 2, +Plate IX. In this test, the speed of the drum carrying the black powder +negative was reduced to one sixty-fourth of that for the permissible +explosives, in order that the photograph might come within the limits of +the negative. In other words, the duration of the black powder flame, as +shown, should be multiplied by 64 for comparison with that of the +permissible explosive, which is from 3,500 to 4,000 times quicker. + +_Apparatus for Measuring Rate of Detonation._--The rate at which +detonation travels through a given length of an explosive can be +measured by an apparatus installed in and near Building No. 17. Its most +essential feature is a recording device, with an electrical connection, +by which very small time intervals can be measured with great exactness. + +The explosive is placed in a sheet-iron tube about 1 in. in diameter +and 4 ft. long, and suspended by cords in a pit, 11 ft. deep and 16 ft. +in diameter. This pit was once used as the well of a gas tank, Fig. 2, +Plate VIII. In adapting the pit to its new use, the tank was cut in two; +the top half, inverted, was placed in the pit on a bed of saw-dust, and +the space between the tank and the masonry walls of the pit was filled +with saw-dust. The cover of the pit consists of heavy timbers framed +together and overlaid by a 12-in. layer of concrete reinforced by six +I-beams. Four straps extend over the top and down to eight "deadmen" +planted about 8 ft. below the surface of the ground. + +The recording device, known as the Mettegang recorder, Fig. 2, Plate +VII, comprises two sparking induction coils and a rapidly revolving +metallic drum driven by a small motor, the periphery of the drum having +a thin coating of lampblack. A vibration tachometer which will indicate +any speed between 50 and 150 rev. per sec., is directly connected to the +drum, so that any chance of error by slipping is eliminated. The wires +leading to the primary coils of the sparking coils pass through the +explosive a meter or more apart. Wires lead from the secondary coils to +two platinum points placed a fraction of a millimeter from the periphery +of the drum. A separate circuit is provided for the firing lines. + +In making a test, the separate cartridges, with the paper trimmed from +the ends, are placed, end to end, in the sheet-iron tube; the drum is +given the desired peripheral speed, and the charge is exploded. The +usual length between the points in the tube is 1 m., and the time +required for the detonation of a charge of that length is shown by the +distance between the beginning of two rows of dots on the drum made by +the sparks from the secondary coil circuits, the dots starting the +instant the primary circuits are broken by the detonation. At one end of +the drum are gear teeth, 1 mm. apart on centers, which can be made to +engage a worm revolving a pointer in front of a dial graduated to +hundredths; by means of this and a filar eyepiece, the distance between +the start of the two rows of spark dots on the drum can be measured +accurately to 0.01 mm. As the drum is 500 mm. in circumference, and its +normal speed is 86 rev. per sec., it is theoretically possible to +measure time to one four-millionth of a second, though with a cartridge +1 m. long, such refinement has not been found necessary. + +The use of small lead blocks affords another means of determining the +rate of detonation or quickness of an explosive. Each block (a cylinder, +2 in. long and 1 in. in diameter) is enclosed in a piece of paper so +that a shell is formed above the block, in which to place the charge. A +small steel disk of the same diameter as the block is first placed in +the shell on top of the block, then the charge with a detonator is +inserted. The charge is customarily 100 grammes. On detonation of the +charge, a deformation of the lead takes place, the amount of which is +due to the quickness of the explosive used (Fig. 3, Plate VIII). + +Sample Record of Tests. + +The procedure followed in the examination of an explosive is shown by +the following outline: + +1.--_Physical Examination._ + + (_a_).--Record of appearance and marks on original package. + + (_b_).--Dimensions of cartridge. + + (_c_).--Weight of cartridge, color and specific gravity of powder. + +2.--_Chemical Analysis._ + + (_a_).--Record of moisture, nitro-glycerine, sodium or potassium + nitrate, and other chemical constituents, as set forth by the + analysis; percentage of ash, hygroscopic coefficient--the amount of + water taken up in 24 hours in a saturated atmosphere, at 15 cent., + by 5 grammes, as compared with the weight of the explosive. + + (_b_).--Analysis of products of combustion from 100 grammes, including + gaseous products, solids, and water. + + (_c_).--Composition of gaseous products of combustion, including + carbon monoxide and carbon dioxide, hydrogen, nitrogen, etc. + + (_d_).--Composition of solid products of combustion, subdivided into + soluble and insoluble. + +_3.--A Typical Analysis of Natural Gas._ + +Used in tests, as follows: + + Carbon dioxide 0.0 per cent. + Heavy hydrocarbons 0.2 " " + Oxygen 0.1 " " + Carbon monoxide 0.0 " " + Methane 82.4 " " + Ethane 15.3 " " + Nitrogen 2.0 " " + ----- + 100.00 per cent. + +_4.--Typical Analysis of Bituminous Coal Dust, 100-Mesh Fine, Used in +Tests._ + + Moisture 1.90 + Volatile matter 35.05 + Fixed carbon 58.92 + Ash 4.13 + ------ + 100.00 + Sulphur 1.04 + +_5.--An Average Analysis of Detonators._ + +Used on Trauzl lead blocks, pressure gauge, calorimeter, and small lead +blocks: + + M - l(l/m). Triple-strength exploder. + + Charge 1.5729 grammes. + + Mercury Chlorate + fulminate. of potash. + Specification 89.73 10.27 + +Used on all other tests: + + M - 260(l/m). Double-strength exploder. + + Charge 0.9805 grammes. + + Mercury Chlorate + fulminate. of potash. + Specification 91.31 8.69 + +_6.--Ballistic-Pendulum Tests._ + +This record includes powder used, weight of charge, swing of mortar, and +unit disruptive charge, the latter being the charge required to produce +a swing of the mortar equal to that produced by lb. (227 grammes) of +40% dynamite, or 3.01 in. + +_7.--Record of Tests._ + +Tests Nos. 1 to 5 in Gallery No. 1, as set forth in preceding circular. + +_8.--Trauzl Lead-Block Test._ + +Powder and test numbers, expansion of bore-hole in cubic centimeters, +and average expansion compared with that produced by a like quantity (10 +grammes) of 40% dynamite, the latter giving an average expansion of 294 +cu. cm. + +_9.--Pressure Gauge._ + +Powder and test number, weight of charge, charging density, height of +curve, pressure developed, and pressure developed after cooling, +compared with pressure developed after elimination of surface influences +by a like quantity (100 grammes) of 40% dynamite, the average being +8,439 kg. per sq. cm. + +_10.--Rate of Detonation._ + +Powder and test number, size of cartridge, and rate of detonation in +meters per second, for comparison with rate of detonation of 40% +dynamite, which, under the same conditions, averages 4,690 m. per sec. + +_11.--Impact Machine._ + +Explosive and test numbers, distance of fall (2,000-gramme weight) +necessary to cause explosion, for comparison with length of fall, 11 +cm., necessary to cause explosion of 40% dynamite. + +_12.--Distance of Explosive Wave Transmitted by 1.25 by 8-in. +Cartridge._ + +Explosive and test numbers, weight of cartridge, distance separating +cartridges in tests, resulting explosion or non-explosion, for +comparison with two cartridges of 40% dynamite, hung, under identical +conditions, 13 in. apart, end to end, in which case detonation of the +first cartridge will explode the second. + +_13.--Flame Test._ + +Explosive and test numbers, charge 100 grammes with 1 lb. of clay +stemming, average length of flame and average duration of flame, for +comparison with photographs produced by 40% dynamite under like +conditions. + + [Illustration: PLATE X. + + Fig. 1.--Separator for Grading Black Powder. + + Fig. 2.--Safety Lamp Testing Gallery. + + Fig. 3.--Mine Gallery No. 2.] + +_14.--Small Lead Blocks._ + +Powder and test numbers, weight of charge, and compression produced in +blocks. + +_15.--Calories Developed._ + +Number of large calories developed per kilogramme of explosive, for +comparison with 1,000 grammes of 40% dynamite, which develop, on an +average, 1,229 large calories. + +Blasting Powder Separator. + +The grains of black blasting powder are graded by a separator, similar +to those used in powder mills, but of reduced size. It consists of an +inclined wooden box, with slots on the sides to carry a series of +screens, and a vertical conduit at the end for carrying off the grains +as they are screened into separate small bins (Fig. 1, Plate X). At the +upper end of the screens is a small 12 by 16-in. hopper, with a sliding +brass apron to regulate the feed. The screens are shaken laterally by an +eccentric rod operated by hand. The top of the hopper is about 6 ft. +above the floor. The box is 6 ft. 10 in. long, from tip to tip, and +inclines at an angle of 9 degrees. + +After separation the grains fall through a vertical conduit, and thence +to the bins through zinc chutes, 1 by 2 in. in section. Care is taken to +have no steel or iron exposed to the powder. + +The screens are held by light wooden frames which slip into the inclined +box from the upper end. In this way, any or all of the screens may be +used at once, thus separating all grades, or making only such +separations as are desired. The screens with the largest meshes are +diagonally-perforated zinc plates. Table 2 gives the number of holes per +square foot in zinc plates perforated with circular holes of the +diameters stated. + + TABLE 2.--Number of Holes per Square Foot in Zinc Plates with Circular + Perforations. + + -------------+------------ + Diameter, | Number + in inches | of holes. + -------------+------------ + 1/2 | 353 + 4/10 | 518 + 1/3 | 782 + 1/4 | 1,392 + 1/6 | 1,680 + 1/8 | 3,456 + 1/10 | 6,636 + 1/16 | 12,800 + -------------+------------ + +The finer meshes are obtained by using linen screens with holes of two +sizes, namely, 1/20 in. square and 1/28 in. square. + +Until a few years ago, black blasting powder was manufactured in the +sizes given in Table 3. + + TABLE 3.--Gradation of Black Blasting Powder. + + ---------+----------- + Grade. | Mesh. + ---------+----------- + CC | 2 - 2 + C | 2 - 3 + F | 3 - 5 + FF | 5 - 8 + FFF | 8 - 16 + FFFF | 16 - 28 + ---------+----------- + +In late years there has been considerable demand for special sizes and +mixed grains for individual mines, especially in Illinois. As no +material change has been made in the brands, the letters now used are +not indicative of the size of the grains, which they are supposed to +represent. Of 29 samples of black blasting powder recently received from +the Illinois Powder Commission, only 10 were found to contain 95% of the +size of grains they were supposed to represent; 4 contained 90%; 7 +varied from 80 to 90%; several others were mixtures of small and large +grains, and were branded FF black blasting powder; and one sample +contained only 8.5% of the size of grains it was supposed to represent. +The remaining samples showed many variations, even when sold under the +same name. The practice of thus mixing grades is exceedingly dangerous, +because a miner, after becoming accustomed to one brand of FF powder of +uniform separation, may receive another make of similar brand but of +mixed grains, and, consequently, he cannot gauge the quantity of powder +to be used. The result is often an over-load or a blown-out shot. The +smaller grains will burn first, and the larger ones may be thrown out +before combustion is complete, and thus ignite any fire-damp present. + +Lamp Testing Gallery. + +At the Pittsburg testing station, there is a gallery for testing safety +lamps in the presence of various percentages of inflammable gas. In this +gallery the safety of the lamps in these gaseous mixtures may be tested, +and it is also possible for mine inspectors and fire bosses to bring +their safety lamps to this station, and test their measurements of +percentage of gas, by noting the length and the appearance of the flame +in the presence of mixtures containing known percentages of methane and +air. + + [Illustration: PLATE XI. + + Fig. 1.--Impact Machine. + + Fig. 2.--Lamp Testing Box.] + +The gas-tight gallery used for testing the lamps, consists of a +rectangular conduit (Fig. 2, Plate X), having sheet-steel sides, 6 mm. +thick and 433 mm. wide, the top and bottom being of channel iron. The +gallery rests on two steel trestles, and to one end is attached a No. 5 +Koerting exhauster, capable of aspirating 50 cu. m. per min., under a +pressure of 500 mm. of water, with the necessary valve, steam separator, +etc. The mouth of the exhauster passes through the wall of the building +and discharges into the open air. + +Besides the main horizontal conduit, there are two secondary conduits +connected by a short horizontal length, and the whole is put together so +that the safety lamp under test may be placed in a current of air, or of +air and gas, which strikes it horizontally, vertically upward or +downward, or at an angle of 45 (Fig. 3). The path of the current is +determined by detachable sheet-steel doors. + + [Illustration: Fig. 3. + + SAFETY LAMP TESTING GALLERY] + +There are five double observing windows of plate glass, which open on +hinges. The size of each window is 7 by 3 in.; the inner glass is in. +thick and the outer one, in. thick. These glasses are separated by a +space of in. The upper conduit has four safety doors along the top, +each of the inclined conduits has one safety door, and the walls and +windows are provided with rubber gaskets or asbestos packing, to make +them gas-tight. The cross-sectional area of the conduit is 434 sq. cm. + +The air inlet consists of 36 perforations, 22 mm. in diameter, in a +bronze plate or diaphragm. The object of this diaphragm is to produce +pressure in the conduit before the mixing boxes, and permit the +measuring of the velocity of the current. The air-current, after passing +through the holes, enters the mixer, a cast-steel box traversed by 36 +copper tubes, each perforated by 12 openings, 3 mm. in diameter, +arranged in a spiral along its length and equally spaced. The total +cross-sectional area of the tubes is 137 sq. cm. + +The explosive gas enters the interior of the box around the tubes +through large pipes, each 90 mm. in diameter, passes thence through the +432 openings in the copper tubes, and mixes thoroughly with the air +flowing through these tubes. The current through the apparatus is +induced by the exhauster, and its course is determined by the position +of the doors. + +The gallery can be controlled so as to provide rapidly and easily a +current of known velocity and known percentage of methane. In the +explosive current of gas and air, safety lamps of any size or design can +be tested under conditions simulating those found occasionally in mines, +air-currents containing methane in dangerous proportions striking the +lamps at different angles, and the relative safety of the various types +of lamps under such conditions can be determined. In this gallery it is +also possible to test lighting devices either in a quiet atmosphere or +in a moving current, and, by subjecting the lamps to air containing +known percentages of methane, it is possible to acquaint the user with +the appearance of the flame caps. + +Breathing Apparatus. + +With this apparatus, the wearer may explore a gaseous mine, approach +fires for the purpose of fighting them, or make investigations after an +explosion. Its object is to provide air or oxygen to be breathed by the +wearer in coal mines, when the mine air is so full of poisonous gases as +to render life in its presence impossible. + +A variety of forms of rescue helmets and apparatus are on the market, +almost all of European manufacture, which are being subjected to +comparative trials as to their durability and safety, the ease or +inconvenience involved in their use, etc. All consist essentially of +helmets which fit air-tight about the head, or of air-tight nose clamps +and mouthpieces (Fig. 1, Plate XII). + +These several forms of breathing apparatus are of three types: + +1.--The liquid-air type, in which air, in a liquid state, evaporates and +provides a constant supply of fresh air. + +2.--The chemical oxygen-producing type, which artificially makes or +supplies oxygen for breathing at about the rate required; and, + +3.--The compressed-oxygen type. + + [Illustration: PLATE XII. + + Fig. 1.--Breathing and Rescue Apparatus. + + Fig. 2.--Rescue Training Room.] + +Apparatus of the first type, weighing 20 lb., supplies enough air to +last about 3 hours, and the products of breathing pass through a +check-valve directly into space. Apparatus of the second type supplies +oxygen obtained from oxygen-producing chemicals, and also provides means +of absorbing the carbonic acid gas produced in respiration. They contain +also the requisite tubes, valves, connections, etc., for the +transmission of the fresh air and the respired air so as to produce +sufficient oxygen while in use; to absorb and purify the products of +expiration; and to convey the fresh air to the mouth without +contamination by the atmosphere in which the apparatus is used. Three +oxygen-generating cartridges are provided, each supplying oxygen enough +for 1 hour, making the total capacity 3 hours. Changes of cylinders can +be made in a few seconds while breathing is suspended. This apparatus +weighs from 20 to 25 lb., according to the number of oxygen generators +carried. The cartridges for generating oxygen, provided with this +apparatus, are of no value after having been used for about an hour. + +The third type of apparatus is equipped with strong cylinders charged +with oxygen under high pressure; two potash regenerative cans for +absorbing the carbon dioxide gas exhaled; a facial helmet; the necessary +valves, tubes, etc., for the control of the oxygen; and a finimeter +which registers the contents of the cylinders in atmospheres and minutes +of duration. The two cartridges used for absorbing the carbonic acid gas +are of no value after having been in use for two hours. + +If inhalation is through the mouth alone, a mouthpiece is attached to +the end of the breathing tube by which the air or oxygen is supplied, +the nose is closed by a clip, and the eyes are protected by goggles. To +inhale through both nose and mouth, the miner wears a helmet or headgear +which can be made to fit tightly around the face. The helmet has two +tubes attached, one for inspiration and the other for expiration. In the +oxygen-cylinder apparatus these tubes lead to and from rubber sacks used +for pure-air and bad-air reserves. + +Mine-Rescue Training. + +It has been found in actual service that when a miner, equipped with +breathing apparatus for the first time, enters a mine in which an +explosion has occurred, he is soon overcome by excitement or nervousness +induced by the artificial conditions of breathing imposed by the +apparatus, the darkness and heat, and the consciousness that he is +surrounded with poisonous gases. It has also been found that a brief +period of training in the use of such apparatus, under conditions +simulating those encountered in a mine after a disaster, gives the miner +confidence and enables him to use the apparatus successfully under the +strain of the vigorous exertion incident to rescue work. + +The rescue corps consists of five or six miners under the direction of +a mining engineer who is experienced in rescue operations and familiar +with the conditions existing after mine disasters. The miners work in +pairs, so that one may assist the other in case of accident, or of +injury to the breathing apparatus, and so that each may watch the +condition of the oxygen supply, as shown by the gauges in the other's +outfit. + +The training is given in the gas-tight room of Building No. 17, or in +similar rooms at sub-stations (Fig. 2, Plate XII). This room is made +absolutely dark, and is filled with formaldehyde gas, SO_{2}, CO_{2}, or +CO, produced by burning sulphur or charcoal on braziers. At each period +of training, the miners enter and walk a distance of about 1 mile, the +average distance usually traveled from the mine mouth to the working +face or point of explosion. They then remove a number of timbers; lift a +quantity of brick or hard lump-coal into wheel-barrows; climb through +artificial tunnels, up and down inclines, and over surfaces strewn with +coal or stone; operate a machine with a device attached to it, which +automatically records the foot-pounds of work done; and perform other +vigorous exercise, during a period of 2 hours. This routine is repeated +daily during 1 week, after which the rescue corps is considered +sufficiently trained for active service. + +The apparatus used for recording the foot-pounds of work done by the +person operating the work machine within the gas-tight rescue room, +comprises a small dial with electrical connections, which records the +number of strokes made by the machine, and a pencil point which rests on +a paper diaphragm, fastened to a horizontal brass disk. This disk is +driven by clockwork, and makes one complete revolution per hour. When +the machine is in operation, the pencil point works back and forth, +making a broad line on the paper; when the operator of the machine +rests, the pencil point traces a single line. The apparatus thus records +the number of strokes given by the operator during a given time. From +the weight lifted, the height of lift, and the number of strokes in the +given time, the foot-pounds of work are readily calculated. + +Electric Testing Apparatus. + +On the ground floor of Building No. 10, two rooms are occupied as +laboratories for investigating the electrical equipment used in mining +operations. The purpose of these investigations is to ascertain the +conditions under which electricity of various voltages may be used with +safety--in mine haulage, hoisting, pumping, or lighting--in the presence +of dangerous mixtures of explosive gases or of dust. It is also proposed +to test various kinds of insulation and insulators in this laboratory, +and to determine the durability of such insulation in the presence of +such corrosive gases and water as are found in mines. + +A water-proof wooden tank, measuring 15 by 5 by 5 ft., is installed, in +which insulation and insulating materials are tested under either pure +or polluted water. Various electric lighting devices and equipment can +be connected from a switch-board in Building No. 17 with Gas-and-Dust +Gallery No. 2, for testing the effect of such lighting apparatus in the +presence of explosive mixtures of gas and dust, as set forth on page +220. + +In the electrical laboratory, Building No. 10, is a booster set +developing 60 kw., and an appropriate switch-board for taking direct +current at 220 volts from the turbo-generator and converting it into +current varying from 0 to 750 volts. There are also transformers for +developing 60-cycle, alternating current at voltages of from 110 to +2,200. The switch-board is designed to handle these various voltages and +to communicate them to the apparatus under test in Building No. 10, +Gallery No. 2, or elsewhere. + +Tests are in progress of insulating materials for use in mines, and of +electric fuses, lights, etc., in Gallery No. 2 (Fig. 3, Plate X), and in +the lamp-testing box (Fig. 2, Plate XI). It is proposed, at the earliest +possible date, to make comparative tests of the safety of various mine +locomotives and mine-hoisting equipment through the medium of this +laboratory, and it is believed that the results will furnish valuable +information as a guide to the safety, reliability, and durability of +these appliances when electrically operated. + +_Electric Lamp and Fuse Testing Box._--An apparatus for testing safety +lamps and electric lights and fuses, consists of -in. iron plates, +bolted together with 1 in. angle-irons to form a box with inside +dimensions of 18 by 18 by 24 in. The box is placed on a stand at such a +height that the observation windows are on a level with the observer's +eye (Fig. 2, Plate XI), and it is connected, by a gas-pipe, with a +supply of natural gas which can be measured by a gas-holder or meter +alongside the box. + +By the use of this apparatus the effect of explosive gas on flames, of +electric sparks on explosive mixtures of gas and air, and of breaking +electric lamps in an explosive mixture of gas and air, may be studied. +The safety lamps are introduced into the box from beneath, through a +hole 6 in. square, covered with a hinged iron lid, admission to which is +had through a flexible rubber sleeve, 20 in. long. + +The behavior of the standard safety lamp and of the safety lamps +undergoing test may be compared in this box as to height of flame for +different percentages of methane in the air, the effect of such flames +in igniting gas, etc. + +In each end of the box is an opening 1 ft. square, over which may be +placed a paper diaphragm held by skeleton doors, the purpose of which is +to confine the gas in such a manner that, should an explosion occur, no +damage would be done. In the front of the box are two plate-glass +observing windows, 2-5/8 by 5 in. In the side of the box, between the +two windows, is a 3/8-in. hole, which can be closed by a tap-screw, +through which samples for chemical analysis are drawn. + +The gasometer consists of two iron cans, the lower one being open at the +top and filled with water and the upper one open at the bottom and +suspended by a counterweight. The latter has attached to its upper +surface a scale which moves with it, thereby measuring the amount of gas +in the holder. A two-way cock permits the admission of gas into the +gasometer and thence into the testing box. + +_Gas-and-Dust Gallery No. 2._--This gallery is constructed of sheet +steel and is similar to Gallery No. 1, the length, however, being only +30 ft. and the diameter 10 ft. It rests on a concrete foundation (Fig. +3, Plate X). Diaphragms can be placed across either extremity, or at +various sections, to confine the mixtures of gas and air in which the +tests are made. The admission of gas is controlled by pipes and valves, +and the gas and air can be stirred or mixed by a fan, as described for +Gallery No. 1, and as shown by Fig. 1. + +Gallery No. 2 is used for investigating the effect of flames of various +lamps, of electric currents, motors, and coal-cutting machines, in the +presence of known mixtures of explosive gas and air. It is also used for +testing the length of flame of safety lamps in still air carrying +various proportions of methane, and, for this purpose, is more +convenient than the lamp gallery. In tests with explosive mixtures, +after the device to be tested has been introduced and preparations are +completed, operations are controlled from a safe distance by a +switch-board in a building near-by. + +Among other investigations conducted in this gallery are those of the +effect of sparks on known gas mixtures. These sparks are such as those +struck from a pick on flint, but in this case they are produced by +rubbing a rapidly revolving emery wheel against a steel file. The effect +of a spark produced by a short circuit of known voltage, the flame from +an arc lamp, etc., may also be studied in this gallery. + + +STRUCTURAL MATERIALS INVESTIGATIONS. + +The structural materials investigations are being conducted for the +purpose of determining the nature and extent of the materials available +for use in the building and construction work of the Government, and how +these materials may be used most efficiently. + +These investigations include: + +(1).--Inquiries into the distribution and local availability, near each +of the building centers in the United States, of such materials as are +needed by the Government. + +(2).--How these materials may be used most efficiently. + +(3).--Their fire-resisting qualities and strength at different +temperatures. + +(4).--The best and most economic methods of protecting steel by +fire-resistant covering. + +(5).--The most efficient methods of proportioning and mixing the +aggregate, locally available, for different purposes. + +(6).--The character and value of protective coatings, or of various +mixes, to prevent deterioration by sea water, alkali, and other +destructive agencies. + +(7).--The kinds and forms of reinforcement for concrete necessary to +secure the greatest strength in beams, columns, floor slabs, etc. + +(8).--Investigation of the clays and of the products of clays needed in +Government works, as to their strength, durability, suitability as +fire-resisting materials, and the methods of analyzing and testing clay +products. + +(9).--Tests of building stones, and investigations as to their +availability near the various building centers throughout the United +States. + +The operations of the Structural Materials Division include +investigations into cement-making materials, constituent materials of +concrete, building stones, clays, clay products, iron, steel, and +miscellaneous materials of construction, for the use of the Government. +The organization comprises a number of sections, including those for the +chemical and physical examination of Departmental purchases; field +sampling and laboratory examination of constituent materials of concrete +collected by skilled field inspectors in the neighborhood of the larger +commercial and building centers; similar field sampling of building +stones and of clays and clay products, offered for use in Government +buildings or engineering construction; and the forwarding of such +samples to the testing laboratories at St. Louis or Pittsburg for +investigation and test. The investigative tests include experiments +regarding destructive agencies, such as electrolysis, alkaline earths +and waters, salt water, fire, and weathering; also experiments with +protective and water-proofing agencies, including the various washes or +patented mixtures on the market, and the methods of washing, and mixing +mortars and concrete, which are likely to result in rendering such +materials less pervious to water. + +Investigations are also being conducted to determine the nature and +extent of materials available for use in the building-construction work +of the Government, and how these materials may be used most efficiently +and safely. While the act authorizing this work does not permit +investigations or tests for private parties, it is believed that these +tests for the Government cannot fail to be of great general value. The +aggregate expenditure by the Federal Government in building and +engineering construction is about $40,000,000 annually. This work is +being executed under so many different conditions, at points so widely +separated geographically, and requires so great a variety of materials, +that the problems to be solved for the Government can hardly fail to +cover a large share of the needs of the Engineering Profession, State +and municipal governments, and the general public. + +_Character of the Work._--The tests and analyses, of the materials of +construction purchased by the various bureaus and departments for the +use of the Government, are to determine the character, quality, +suitability, and availability of the materials submitted, and to +ascertain data leading to more accurate working values as a basis for +better working specifications, so as to enable Government officials to +use such materials with more economy and increased efficiency. + +Investigative tests of materials entering into Government construction, +relative to the larger problems involved in the use of materials +purchased by the Government, include exhaustive study of the suitability +for use, in concrete construction on the Isthmian Canal, of the sand and +stone, and of the cementing value of pozzuolanic material, found on the +Isthmus; the strength, elasticity, and chemical properties of structural +steel for canal lock-gates; of wire rope and cables for use in hoisting +and haulage; and the most suitable sand and stone available for concrete +and reinforced concrete for under-water construction, such as the +retaining walls being built by the Quartermaster's Department of the +Army, in San Francisco Harbor. + +These tests also include investigations into the disintegrating effect +of alkaline soil and water on the concrete and reinforced concrete +structures of the Reclamation Service, with a view to preventing such +disintegration; investigations into the proper proportions and +dimensions of concrete and reinforced concrete structural columns, +beams, and piers, and of walls of brick and of building stone, and of +the various types of metal used for reinforcement by the Supervising +Architect in the construction of public buildings; investigations into +the sand, gravel, and broken stone available for local use in concrete +construction, such as columns, piers, arches, floor slabs, etc., as a +guide to the more economical design of public structures, and to +determine the proper method of mixing the materials to render the +concrete most impervious to water and resistant to weather and other +destructive agencies. + +Other lines of research may be stated briefly as follows: + +The extent to which concrete made from cement and local materials can be +most safely and efficiently used for different purposes under different +conditions; + +The best methods for mixing and utilizing the various constituent +materials locally available for use in Government construction; + +The materials suitable for the manufacture of cement on the public +lands, or where the Government has planned extensive building or +engineering construction work, where no cement plants now exist; + +The kinds and forms of reinforcement for concrete, and the best methods +of applying them in order to secure the greatest strength in +compression, tension, shear, etc., in reinforced concrete beams, +columns, floor slabs, etc.; + +The influence of acids, oils, salts, and other foreign materials, +long-continued strain, or electric currents, on the permanence of the +steel in reinforced concrete; + +The value of protective coatings as preventives of deterioration of +structural materials by destructive agencies; and + +The establishment of working stresses for various structural materials +needed by the Government in its buildings. + +Investigations are being made into the effects of fire and the rate of +conductivity of heat on concrete and reinforced concrete, brick, tile, +building stone, etc., as a guide to the use of the most suitable +materials for fire-proof building construction and the proper +dimensioning of fire-resistive coverings. + +Investigations and tests are being made, with a view to the preparation +of working specifications for use in Government construction, of bricks, +tile, sand-lime brick, paving brick, sewer pipe, roofing slates, +flooring tiles, cable conduits, electric insulators, architectural terra +cotta, fire-brick, and all shapes of refractories and other clay +products, regarding which no satisfactory data for the preparation of +specifications of working values now exist. + +Investigations of the clay deposits throughout the United States are in +progress, to determine proper methods of converting them into building +brick, tile, etc., at the most reasonable cost, and the suitability of +the resulting material for erection in structural forms and to meet +building requirements. + +Investigations are being made in the field, of building stones locally +available, and physical and chemical tests of these building stones to +determine their bearing or crushing strength; the most suitable mortars +for use with them; their resistance to weathering; their fire-resistive +and fire-proof qualities, etc., regarding which practically no adequate +information is available as a guide to Government engineering and +building design. + +_Results Accomplished._--During one period of six months alone, more +than 2,500 samples, taken from Government purchases of structural +materials, were examined, of which more than 300 failed to meet the +specified requirements, representing many thousands of dollars worth of +inferior material rejected, which otherwise would have been paid for by +the Government. These tests were the means of detecting the inferior +quality of large quantities of materials delivered on contracts, and the +moral effect on bidders has proven as important a factor in the +maintenance of a high quality of purchases, as in the saving of money. + +The examination of sands, gravels, and crushed stones, as constituent +materials for concrete and reinforced concrete construction, has +developed data showing that certain materials, locally available near +large building centers and previously regarded as inferior in quality, +were, in fact, superior to other and more expensive materials which it +had been proposed to use. + +These investigations have represented an actual saving in the cost of +construction on the work of the Isthmian Canal Commission, of the +Supervising Architect, and of certain States and cities which have +benefited by the information disseminated regarding these constituent +materials. + +Investigations of clay products, only recently inaugurated, have already +resulted in the ascertainment of important facts relative to the colloid +matter of clay and its measurement, and the bearing thereof on the +plasticity and working values of various clays. The study of the +preliminary treatment of clays difficult to handle dry, has furnished +useful information regarding the drying of such clays, and concerning +the fire resistance of bricks made of soft, stiff, or dried clay of +various densities. + +The field collection and investigation of building-stone samples have +developed some important facts which had not been considered previously, +relative to the effect of quarrying, in relation to the strike and dip +of the bedding planes of building stone, and the strength and durability +of the same material when erected in building construction. These +investigations have also developed certain fundamental facts relative to +the effects of blasting (as compared with channeling or cutting) on the +strength and durability of quarried building stone. + +_Mineral Chemistry Laboratories._--Investigations and analyses of the +materials of engineering and building construction are carried on at +Pittsburg in four of the larger rooms of Building No. 21. In this +laboratory, are conducted research investigations into the effect of +alkaline waters and soils on the constituent materials of concrete +available in arid regions, as related to the life and permanency of the +concrete and reinforced concrete construction of the Reclamation +Service. These investigations include a study of individual salts found +in particular alkalis, and a study of the results of allowing solutions +of various alkalis to percolate through cylinders of cement mortar and +concrete. Other research analyses have to do with the investigation of +destructive and preservative agencies for concrete, reinforced concrete, +and similar materials, and with the chemistry of the effects of salt +water on concrete, etc. The routine chemical analyses of the constituent +materials of concrete and cement-making materials, are made in this +laboratory, as are also a large number of miscellaneous chemical +analyses and investigations of reinforcement metal, the composition of +building stones, and allied work. + +A heat laboratory, in charge of Dr. J. K. Clement, occupies three rooms +on the ground floor of Building No. 21, and is concerned chiefly with +the measurement of temperatures in gas producers, in the furnaces of +steam boilers, kilns, etc. The work includes determinations of the +thermal conductivity of fire clays, concrete, and other building +materials, and of their fire-resisting properties; measurements of the +thermal expansion and specific heats of fire-bricks, porcelain, and +glazes; and investigations of the effect of temperature variations on +the various chemical processes which take place in the fuel bed of the +gas producer, boiler furnace, etc. + +The heat laboratory is equipped for the calibration of the thermometers +and pyrometers, and electrical and other physical apparatus used by the +various sections of the Technologic Branch. + +For convenience in analyzing materials received from the various +purchasing officers attached to the Government bureaus, this work is +housed in a laboratory on the fourth floor of the Geological Survey +Building in Washington. + +Large quantities and many varieties of building materials for use in +public buildings under contract with the Supervising Architect's office, +are submitted to the laboratory by contractors to determine whether or +not they meet the specified requirements. Further examinations are made +of samples submitted by superintendents of construction, representing +material actually furnished by contractors. It is frequently found that +the sample of material submitted by the contractor is of far better +quality than that sent by the superintendent to represent deliveries. +The needed constant check on deliveries is thus provided. + +In addition to this work for the office of the Supervising Architect, +similar work on purchases and supplies is carried on for the Isthmian +Canal Commission, the Quartermaster-General's Department of the Army, +the Life Saving Service, the Reclamation Service, and other branches of +the Government. About 300 samples are examined each month, requiring an +average of 12 determinations per sample, or about 3,600 determinations +per month. + +The chemical laboratory for testing Government purchases of structural +materials is equipped with the necessary apparatus for making the +requisite physical and chemical tests. For the physical tests of cement, +there are a tensile test machine, briquette moulds, a pat tank for +boiling tests to determine soundness, water tanks for the storage of +briquettes, a moist oven, apparatus to determine specific gravity, +fineness of grinding, etc. + +The chemical laboratory at Washington is equipped with the necessary +analytical balances, steam ovens, baths, blast lamps, stills, etc., +required in the routine chemical analysis of cement, plaster, clay, +bricks and terra cotta, mineral paints and pigments, roofing material, +tern plate and asphaltic compounds, water-proofing materials, iron and +steel alloys, etc. + +At present, materials which require investigative tests as a basis for +the preparation of suitable specifications, tests not connected with the +immediate determination as to whether or not the purchases are in +accordance with the specifications, are referred to the chemical +laboratories attached to the Structural Materials Division, at +Pittsburg. + +The inspection and tests of cement purchased in large quantities, such +as the larger purchases on behalf of public-building construction under +the Supervising Architect, or the great 4,500,000-bbl. contract of the +Isthmian Canal Commission, are made in the cement-testing laboratory of +the Survey, in the Lehigh Portland cement district, at Northampton, Pa. + +_Testing Machines._--The various structural forms into which concrete +and reinforced concrete may be assembled for use in public-building +construction, are undergoing investigative tests as to their compressive +and tensile strength, resistance to shearing, modulus of elasticity, +coefficient of expansion, fire-resistive qualities, etc. Similar tests +are being conducted on building stone, clay products, and the structural +forms in which steel and iron are used for building construction. + +The compressive, tensile, and other large testing machines, for all +kinds of structural materials reaching the testing stations, are under +the general supervision of Richard L. Humphrey, M. Am. Soc. C. E. The +immediate direction of the physical tests on the larger testing machines +is in charge of Mr. H. H. Kaplan. + +Most of this testing apparatus, prior to 1909, was housed in buildings +loaned by the City of St. Louis, in Forest Park, St. Louis, Mo., and the +arrangement of these buildings, details of equipment, organization, and +methods of conducting the tests, are fully set forth in Bulletin No. 329 +of the U.S. Geological Survey. In brief, this equipment included +motor-driven, universal, four-screw testing machines, as follows: One +600,000-lb., vertical automatic, four-screw machine; one 200,000-lb., +automatic, four-screw machine; and one 200,000-lb. and one 100,000-lb. +machine of the same type, but with three screws. There are a number of +smaller machines of 50,000, 40,000, 10,000, and 2,000 lb., respectively. + +These machines are equipped so that all are available for making tensile +and compressive tests (Fig. 1, Plate XIII). The 600,000-lb. machine is +capable of testing columns up to 30-ft. lengths, and of making +transverse tests of beams up to 25-ft. span, and tension tests for +specimens up to 24 ft. in length. The smaller machines are capable of +making tension and compressive tests up to 4 ft. in length and +transverse beam tests up to 12 ft. span. In addition, there are ample +subsidiary apparatus, including concrete mixers with capacities of and +1 cu. yd., five hollow concrete block machines, automatic sifting +machines, briquette moulds, storage tanks, etc. + +At the Atlantic City sub-station, there is also a 200,000-lb., +universal, four-screw testing machine, with miscellaneous equipment for +testing cement and moulding concrete, etc.; and at the Northampton +sub-station, there is a complete equipment of apparatus for cement +testing, capable of handling 10,000 bbl. per day. + +At the Pittsburg testing station, a 10,000,000-lb., vertical, +compression testing machine (Plate XIV), made by Tinius Olsen and +Company, is being erected for making a complete series of comparative +tests of various building stones of 2, 4, and 12-in. cube, of stone +prisms, 12 in. base and 24 in. high, of concrete and reinforced concrete +columns up to 65 ft. in height, and of brick piers and structural-steel +columns up to the the limits of the capacity and height of the machine. + + [Illustration: PLATE XIII. + + Fig. 1.--Testing Beam in 200,000-Lb. Machine. + + Fig. 2.--Fire Test of Panel.] + +This machine is a large hydraulic press, with an adjustable head, and a +weighing system for recording the loading developed by a triple-plunger +pump. It has a maximum clearance of 65 ft. between heads; the clearance +in the machine is a trifle more than 6 ft. between screws, and the heads +are 6 ft. square. + +The machine consists of a base containing the main cylinder, with a +sectional area of 2,000 sq. in., upon which rests the lower platform or +head, which is provided with a ball-and-socket bearing. The upper head +is adjustable over four vertical screws, 13 in. in diameter and 72 ft. +2 in. long, by a system of gearing operating four nuts with +ball-bearings upon which the head rests. The shafting operating this +mechanism is connected with a variable-speed motor which actuates +the triple-plunger pump supplying the pressure to the main cylinder +(Fig. 4). + +The weighing device consists of a set of standard Olsen levers for +weighing one-eightieth of the total load on the main cylinder. This +reduction is effected through the medium of a piston and a diaphragm. +The main cylinder has a diameter of 50 in., and the smaller one, a +diameter of 5-9/16 in. The weighing beam is balanced by an +automatically-operated poise weight, and is provided with a device for +applying successive counterweights of 1,000,000 lb. each. Each division +on the dial is equivalent to a 100-lb. load, and smaller subdivisions +are made possible by an additional needle-beam. + +The power is applied by a 15-h.p., 220-volt, variable-speed motor +operating a triple-plunger pump, the gearing operating the upper head +being driven by the same motor. The extreme length of the main screws +necessitates splicing, which is accomplished as follows: + +In the center of the screws, at the splice, is a 3-in. threaded pin for +centering the upper and lower screws; this splice is strengthened by +sleeve nuts, split to facilitate their removal whenever it is necessary +to lower the upper head; after the head has passed the splice, the +sleeve nuts are replaced. + +In order to maintain a constant load, a needle-valve has been provided, +which, when the pump is operated at its lowest speed, will allow a +sufficient quantity of oil to flow into the main cylinder to equalize +whatever leakage there may be. The main cylinder has a vertical movement +of 24 in. The speed of the machine, for the purpose of adjustment, using +the gearing attached to the upper head, is 10 in. per min. The speed for +applying loads, controlled by the variable-speed motor driving the pump, +varies from a minimum of at least 1/60 in. per min. to a maximum of at +least in. per min. The machine has a guaranteed accuracy of at least +one-third of 1%, for any load of more than 100,000 lb., up to its +capacity. + + [Illustration: Fig. 4. + + PLAN AND ELEVATION OF 10,000,000-LB. VERTICAL COMPRESSION + TESTING MACHINE] + +The castings for the base and the top head weigh approximately 48,000 +lb. each. Each main screw weighs more than 40,000 lb., the lower +platform weighing about 25,000 lb., and the main cylinder, 16,000 lb. +The top of the machine will be about 70 ft. above the top of the floor, +and the concrete foundation, upon which it rests, is about 8 ft. below +the floor line. + + [Illustration: PLATE XIV. + + 10,000,000-Lb. Testing Machine.] + +_Concrete and Cement Investigations._--The investigations relating to +concrete include the examination of the deposits of sand, gravel, stone, +etc., in the field, the collection of representative samples, and the +shipment of these samples to the laboratory for analysis and test. These +tests are conducted in connection with the investigation of cement +mortars, made from a typical Portland cement prepared by thoroughly +mixing a number of brands, each of which must meet the following +requirements: + + Specific gravity, not less than 3.10; + + Fineness, residue not to exceed 8% on No. 100, nor 25% on No. 200 + sieve; + + Time of setting: Initial set, not less than 30 min.; hard set, not + less than 1 hour, nor more than 10 hours. + + Tensile strength: Requirements applying to neat cement and to 1 part + cement with 3 parts standard sand: + + -------------------------------+--------------+---------- + | Neat cement. | 1:3 Mix. + Time specification. | Pounds. | Pounds. + -------------------------------+--------------+---------- + 24 hours in moist air | 175 | ... + 7 days (1 day in moist air, | 500 | 175 + 6 days in water) | | + 28 days (1 day in moist air, | 600 | 250 + 27 days in water) | | + -------------------------------+--------------+---------- + + Constancy of volume: Pats of neat cement, 3 in. in diameter, in. + thick at center, tapering to a thin edge, shall be kept in moist air + for a period of 24 hours. A pat is kept in air at normal temperature + and observed at intervals for at least 28 days. Another pat is kept in + water maintained as near 70 Fahr. as practicable, and is observed at + intervals for at least 28 days. A third pat is exposed in an + atmosphere of steam above boiling water, in a loosely-closed vessel, + for 5 hours. These pats must remain firm and hard and show no signs of + distortion, checking, cracking, or disfiguration. + + The cement shall not contain more than 1.75% of anhydrous sulphuric + acid, nor more than 4% of magnesium oxide. + + A test of the neat cement must be made with each mortar series for + comparison of the quality of the typical Portland cement. + +The constituent materials are subjected to the following examination and +determinations, and, in addition, are analyzed to determine the +composition and character of the stone, sand, etc.: + + 1.--Mineralogical examination, + + 2.--Specific gravity, + + 3.--Weight, per cubic foot, + + 4.--Sifting (granulometric composition), + + 5.--Percentage of silt and character of same, + + 6.--Percentage of voids, + + 7.--Character of stone as to percentage of absorption, porosity, + permeability, compressive strength, and behavior under treatment. + +Physical tests are made to determine the tensile, compressive, and +transverse strengths of the cement and mortar test pieces, with various +preparations of cement and various percentages of material. Tests are +also made to determine porosity, permeability, volumetric changes in +setting, absorption, coefficient of expansion, effect of oil, etc. + +Investigation of concretes made from mixtures of typical Portland +cement, sand, stone, and gravel, includes tests on cylinders, prisms, +cubes, and other standard test pieces, with various proportions of +materials and at ages ranging from 30 to 360 days. Full-sized plain +concrete beams, moulded building blocks, reinforced concrete beams, +columns, floor slabs, arches, etc., are tested to determine the effect, +character, and amount of reinforcement, the effect of changes in volume, +size, and composition, and the effect of different methods of loading +and of supporting these pieces, etc. + +These investigations include detailed inquiry in the field and research +in the chemical and physical laboratories regarding the effects of +alkaline soils and waters on structures of concrete being built by the +Reclamation Service in the arid regions. It has been noted that on +certain of the Reclamation projects, notably on the Sun River Project, +near Great Falls, Mont., the Shoshone Project, near Cody, Wyo., and the +Carlsbad and Hondo Projects in the Pecos Valley, N. Mex., structures of +concrete, reinforced concrete, building stones, brick, and tile, show +evidence of disintegration. This is attributed to the effects of +alkaline waters or soils coming into contact with the structures, or to +the constituent materials used. In co-operation with the Reclamation +Service, samples of the waters, soils, and constituent materials, are +collected in the field, and are subjected to careful chemical +examination in the mineral laboratories at Pittsburg. + + [Illustration: PLATE XV. + + Fig. 1.--Characteristic Failures of Reinforced Concrete Beams. + + Fig. 2.--Arrangement of Static Load Test for Reinforced + Concrete Beams.] + +The cylinders used in the percolation tests are composed of typical +Portland cement mixed with sand, gravel, and broken stone of known +composition and behavior, and of cement mixed with sand, gravel, and +broken stone collected in the neighborhood of the Reclamation projects +under investigation. + + [Illustration: Fig. 5. + + CROSS-SECTION OF APPARATUS FOR HOLDING PERMEABILITY-TEST PIECES] + +It is also proposed to subject these test pieces, some made with water +of known purity, and others with alkaline water, to contact with +alkaline soils near the projects, and with soil of known composition +near the testing laboratories at Pittsburg. As these tests progress and +other lines of investigation are developed, the programme will be +extended, in the hope that the inquiry may develop methods of preparing +and mixing concrete and reinforced concrete which can be used in +alkaline soils without danger of disintegration. + +Investigations into the effect of salt water on cement mortars and +concretes, and the effect of electrolysis, are being conducted at +Atlantic City, N.J., where the test pieces may be immersed in deep sea +water for longer or shorter periods of time. + +At the Pittsburg laboratory a great amount of investigative work is done +for the purpose of determining the suitability and availability of +various structural materials submitted for use by the Government. While +primarily valuable only to the Government, the results of these tests +are of indirect value to all who are interested in the use of similar +materials. Among such investigations have been those relating to the +strength, elasticity, and chemical properties of wire rope for use in +the Canal Zone; investigations of the suitability and cementing value of +concrete, sand, stone, and pozzuolanic material found on the Isthmus; +investigations as to the relative resistance to corrosion of various +types of wire screens for use in the Canal Zone; into the suitability +for use, in concrete sea-wall construction, of sand and stone from the +vicinity of San Francisco; into the properties of reinforced concrete +floor slabs; routine tests of reinforcing metal, and of reinforced +concrete beams and columns, for the Supervising Architect of the +Treasury Department, etc. The results have been set forth in three +bulletins[9] which describe the methods of conducting these tests and +also tests on constituent materials of concrete and plain concrete +beams. In addition, there are in process of publication a number of +bulletins giving the results of tests on reinforced concrete beams, +columns, and floor slabs, concrete building blocks, etc. + +The Northampton laboratory was established because it is in the center +of the Lehigh cement district, and therefore available for the mill +sampling and testing of purchases of cement made by the Isthmian Canal +Commission; it is also available for tests of cement purchased in the +Lehigh district by the Supervising Architect and others. It is in a +building, the outer walls of which are of cement plaster applied over +metal lath nailed to studding. The partitions are of the same +construction, and the floors and roof are of concrete throughout. + +The inspection at the factories and the sampling of the cement are under +the immediate direction of the Commission; the testing is under the +direction of the U.S. Geological Survey. A large force of employees is +required, in view of the magnitude of the work, which includes the daily +testing of consignments ranging from 5,000 to 10,000 bbl., sampled in +lots of 100 bbl., which is equivalent to from 50 to 100 samples tested +per day. + +The cement to be sampled is taken from the storage bins and kept under +seal by the chief inspector pending the results of the test. The +quantity of cement sampled is sufficient for the tests required under +the specifications of the Isthmian Canal Commission, as well as for +preliminary tests made by the cement company, and check tests made at +the Geological Survey laboratory, at Pittsburg. + +The tests specified by the Commission include determination of specific +gravity, fineness of grinding, time of setting, soundness, tensile +strength (with three parts of standard quartz sand for 7 and 28 days, +respectively), and determination of sulphur anhydride (SO_{3}), and +magnesia (MgO). + +The briquette-making and testing room is fitted with a mixing table, +moist closet, briquette-storage tanks, and testing machines. The mixing +table has a concrete top, in which is set plate glass, 18 in. square and +1 in. thick. Underneath the table are shelves for moulds, glass plates, +etc. + +The moist closet, 5 ft. high, 3 ft. 10 in. wide, and 1 ft. 8 in. deep, +is divided into two compartments by a vertical partition, and each +compartment is fitted with cleats for supporting thirteen tiers of glass +plates. On each pair of cleats, in each compartment, can be placed four +glass plates, each plate containing a 4-gang mould, making storage for +416 briquettes. With the exception of the doors, which are of wood lined +with copper, the closet is of 1:1 cement mortar, poured monolithic, even +to the cleats for supporting the glass plates. + +The immersion tanks, of the same mortar, are in tiers of three, +supported by a steel structure. They are 6 ft. long, 2 ft. wide, and 6 +in. deep, and 2,000 briquettes can be stored in each tank. The overflow +from the top tank wastes into the second, which, in turn, wastes into +the third. Water is kept running constantly. + +The briquette-testing machine is a Fairbanks shot machine with a +capacity of 2,000 lb., and is regulated to apply the load at the rate of +600 lb. per min. Twenty-four 4-gang moulds, of the type recommended by +the Special Committee on Uniform Tests of Cement, of the American +Society of Civil Engineers, are used. + +The room for noting time of set and soundness is fitted with a mixing +table similar to that in the briquette-making room. The Vicat apparatus +is used for determining the normal consistency, and the Gilmore +apparatus for the time of setting. While setting, the soundness pats are +stored in galvanized-iron pans having about 1 in. of water in the +bottom, and covered with dampened felt or burlap. The pats rest on a +rack slightly above the water and well below the felt. + +For specific gravity tests, the Le Chatelier bottles are used. A pan, in +which five bottles can be immersed at one time, is used for maintaining +the benzine at a constant temperature. The samples are weighed on a pair +of Troemner's No. 7 scales. + +The fineness room is fitted with tables, two sets of standard No. 100 +and No. 200 sieves, and two Troemner's No. 7 scales similar to those +used for the specific gravity tests. + +The storage room is fitted with shelves for the storage of samples being +held for 28-day tests. + +The mould-cleaning room contains tables for cleaning moulds, and racks +for air pats. + +An effort is made to keep all the rooms at a temperature of 70 Fahr., +and, with this in view, a Bristol recording thermometer is placed in the +briquette-room. Two wet-and-dry bulb hygrometers are used to determine +the moisture in the air. + +Samples are taken from the conveyor which carries the cement to the +storage bins, at the approximate rate of one sample for each 100 bbl. +After each 4,000-bbl. bin has been filled, it is sealed until all tests +have been made, when, if these have been satisfactory, it is released +for shipment. + +The samples are taken in cans, 9 in. high and 7 in. in diameter. These +cans are delivered in the preparation room where the contents are mixed +and passed through a No. 20 sieve. Separate samples are then weighed out +for mortar briquettes, for soundness pats, and for the specific-gravity +and fineness tests. These are placed in smaller cans and a quantity +sufficient for a re-test is held in the storage room awaiting the +results of all the tests. + +The sample for briquettes is mixed with three parts standard crushed +quartz, and then taken to the briquette-making room, where eight +briquettes are made, four for 7-day and four for 28-day tests. These are +placed in the moist closet in damp air for 24 hours, then removed from +the moulds, and placed in water for the remainder of the test period. At +the proper time they are taken from the immersion tank and broken. + +From the sample for soundness, four pats are made. The time of setting +is determined on one of these pats. They are placed in the pan +previously described, for 24 hours, then one is placed in running water +and one in air for 28 days. The others are treated in the boiler, one in +boiling water for 3 hours and one in steam at atmospheric pressure for 5 +hours. + +The sample taken for specific gravity and fineness is dried in the oven +at 100 cent. in order to drive off moisture. Two samples are then +carefully weighed out, 50 grammes for fineness and 64 grammes for +specific gravity, and the determinations are made. As soon as anything +unsatisfactory develops, a re-test is made. If, however, the cement +satisfies all requirements, a report sheet containing all the data for a +bin, is made out, and the cement is ready for shipment. From every fifth +bin, special neat and mortar briquettes are made, which are intended for +tests at ages up to ten years. + +_Salt-Water Laboratory._--The laboratory at Atlantic City, for +conducting investigations into the effects of salt water on concrete and +reinforced concrete, is situated so that water more than 25 ft. deep is +available for immersion tests of the setting and deterioration of such +materials. + +Through the courtesy of the municipality of Atlantic City, Young's +cottage, on old Young's Pier, has been turned over, at a nominal rental, +to the Geological Survey for the conduct of these tests. The laboratory +building is about 700 ft. from the boardwalk, and occupies a space about +100 by 45 ft. It is one story high, of frame-cottage construction, and +stands on wooden piles at one side of the pier proper and about 20 ft. +above the water, which is about 19 ft. deep at this point. Fresh running +water, gas, electric light, and electric power are supplied to the +building (Fig. 6). + +In this laboratory investigations will be made of the cause of the +failure and disintegration of cement and concrete subjected to the +action of sea water. Tests are conducted so as to approach, as nearly as +possible, the actual conditions found in concrete construction along the +sea coast. All sea-water tests are made in the ocean, some will probably +be paralleled by ocean-water laboratory tests and all by fresh-water +comparative tests. + +Cements, in the form of pats, briquettes, cubes, cylinders, and in a +loose ground state, and also mortars and concretes in cube, cylinder, +and slab form, are subjected to sea water. + +The general plan for the investigations is as follows: + +1.--Determination of the failing elements and the nature of the failure; + +2.--Determination of the value of the theories advanced at the present +time; and, + +3.--Determination of a method of eliminating or chemically recombining +the injurious elements. + +Preliminary tests are in progress, including a study of the effect of +salt water on mortars and concretes of various mixtures and ages. The +proportions of these mixtures and the methods of mixing will be varied +from time to time, as suggested by the progress of the tests. + +_Fire-Proofing Tests._--Tests of the fire-proofing and fire-resistive +properties of various structural materials are carried on in the +laboratories in Building No. 10, at Pittsburg, and in co-operation with +the Board or Fire Underwriters at its Chicago laboratory (Fig. 2, Plate +XIII). These tests include three essential classes of material: (_a_), +clay products, protective coverings representative of numerous varieties +of brick and fire-proofing tiles, including those on the market and +those especially manufactured for these tests in the laboratory at +Pittsburg; (_b_), characteristic granites of New England, with +subsequent tests of the various building stones found throughout the +United States; and (_c_), cement and concrete covering material, +building blocks, and concrete reinforced by steel bars embedded at +different depths for the purpose of studying the effect of expansion on +the protective covering. + +In co-operation with the physical laboratory, these tests include a +study of the relative rates of conductivity of cement mortars and +concretes. By embedding thermo-couples in cylinders composed of the +materials under test, obtaining a given temperature by an electric coil, +and noting the time required to raise the temperature at the various +embedded couples to a given degree, the rate of conductivity may be +determined. Other tests include those in muffles to determine the rate +of expansion and the effect of heat and compressive stresses combined on +the compressive strength of the various structural materials. The +methods of making the panel tests, and the equipment used, are described +and illustrated in Bulletin No. 329, and the results of the tests have +been published in detail.[10] + +_Building Stones Investigations._--The field investigations of building +stones are conducted by Mr. E. F. Burchard, and include the examination +of the various deposits found throughout the United States. A study of +the granites of New England has been commenced, which includes the +collection of type specimens of fine, medium, and coarse-grained +granites, and of dark, medium, and light-gray or white granites. A +comparative series of these granites, consisting of prisms and cubes of +4 and 2 in., respectively, has been prepared. + + [Illustration: Fig. 6. + + PLAN OF LABORATORY FOR SALT-WATER TESTS AT ATLANTIC CITY, N.J.] + +The standard adopted for compressive test pieces in the 10,000,000-lb. +machine is a prism, having a base of 12 in. and being 24 in. high. The +tests include not only those for compression or crushing strength, but +also those for resistance to compressive strains of the prisms and +cubes, when raised to high temperatures in muffles or kilns; resistance +to weathering, freezing, and thawing; porosity; fire-resisting +qualities, etc. + +In collecting field samples, special attention is paid to the occurrence +of the stone, extent of the deposit, strike, dip, etc., and specimens +are procured having their faces cut with reference to the bedding +planes, in order that compressive and weathering tests may be made, not +only in relation to these planes but at those angles thereto in which +the material is most frequently used commercially. Attention is also +paid to the results of blasting, in its relation to compressive strains, +as blasting is believed to have a material effect on stones, especially +on those which may occur in the foundations of great masonry dams, and +type specimens of stone quarried by channeling, as well as by blasting, +are collected and tested. + +_Clay and Clay Products Investigations._--These investigations are in +charge of Mr. A. V. Bleininger, and include the study of the occurrence +of clay beds in various parts of the United States, and the adaptability +of each clay to the manufacture of the various clay products. + +Experiments on grinding, drying, and burning the materials are conducted +at the Pittsburg testing station, to ascertain the most favorable +conditions for preparing and burning each clay, and to determine the +most suitable economic use to which it may be put, such as the +manufacture of building or paving bricks, architectural tiles, sewer +tiles, etc. + +The laboratory is equipped with various grinding and drying devices, +muffles, kilns, and apparatus for chemical investigations, physical +tests, and the manufacture and subsequent investigative tests of clay +products. + +This section occupies the east end of Building No. 10, and rooms on the +first and second floors have been allotted for this work. In addition, a +brick structure, 46 by 30 ft., provided with a 60-ft. iron stack, has +been erected for housing the necessary kilns and furnaces. + + [Illustration: PLATE XVI. + + Fig. 1.--Brick Machine and Universal Cutter. + + Fig. 2.--House-Heating Boilers, Building No. 21.] + +On the ground floor of Building No. 10, adjoining the cement and +concrete section, is a storage room for raw materials and product under +investigation. Adjoining this room, and connecting with it by wide +doors, is the grinding room, containing a 5-ft. wet pan, with 2,000-lb. +rollers, to be used for both dry and wet grinding. Later, a heavy dry +pan is to be installed. With these machines, even the hardest material +can be easily disintegrated and prepared. In this room there is also a +jaw crusher for reducing smaller quantities of very hard material, as +well as a 30 by 16-in. iron ball mill, for fine grinding. These machines +are belted to a line shaft along the wall across the building. Ample +sink drainage is provided for flushing and cleaning the wet pan, when +changing from one clay to another. + +A large room adjoining is for the operation of all moulding and shaping +machines, representing the usual commercial processes. At present these +include an auger machine, with a rotary universal brick and tile cutter, +Fig. 1, Plate XVI, and a set of brick and special dies, a hand repress +for paving brick, and a hand screw press for dry pressing. The brick +machine is operated from the main shaft which crosses the building in +this room and is driven from a 50-h.p. motor. It is possible thus to +study the power consumption under different loads and with different +clays, as well as with varying degrees of water content in the clay. As +the needs of the work demand it, other types of machines are to be +installed. For special tests in which pressure is an important factor it +is intended to fit up one of the compression testing machines of the +cement section with the necessary dies, thus enabling the pressing to be +carried on under known pressures. Crushing, transverse, and other tests +of clay products are made on the testing machines of the cement and +concrete laboratories. + +Outside of the building, in a lean-to, there is a double-chamber rattler +for the testing of paving brick according to the specifications of the +National Brick Manufacturers' Association. + +In the smaller room adjoining the machine laboratory there are two small +wet-grinding ball mills, of two and four jars, respectively, and also a +9-leaf laboratory filter press. + +The remaining room on the first floor is devoted to the drying of clays +and clay wares. The equipment consists of a large sheet-iron drying oven +of special construction, which permits of close regulation of the +temperature (Fig. 7). It is heated by gas burners, and is used for the +preliminary heat treatment of raw clays, in connection with the study of +the drying problems of certain raw materials. It is intended to work +with temperatures as high as 250 cent. + +Another drying closet, heated by steam coils (Fig. 8), intended for +drying various clay products, has been designed with special reference +to the exact regulation of the temperature, humidity, and velocity of +the air flowing through it. Both dryers connect by flues with an iron +stack outside the building. This stack is provided with a suction fan, +driven by a belt from an electric motor. + +On the second floor are the chemical, physical, and research +laboratories, dealing with the precise manipulations of the tests and +investigations. + +The chemical laboratory is fully equipped with the necessary apparatus +for carrying on special chemical research in silicate chemistry, +including electrical resistance furnaces, shaking devices, etc. It is +not the intention to do routine work in this laboratory. The office +adjoins this laboratory, and near it is the physical laboratory, devoted +to the study of the structure of raw materials. The latter contains +Nobel and Schoene elutriators, together with viscosimeters of the flow +and the Coulomb and Clark electrical types, sieves, voluminometers, +colorimeters, vernier shrinkage gauges, micrometers, microscopes, and +the necessary balances. + +The room across the hall is devoted to the study of the specific +gravity, absorption, porosity, permeability, hardness, translucency, +etc., of burnt-clay products, all the necessary apparatus being +provided. In the two remaining rooms, intended for research work, +special apparatus adapted to the particular investigation may be set up. +All the rooms are piped for water, gas, compressed air, steam, and +drainage, and wired for light and power. + +In the kiln house there is a test kiln adapted for solid fuel and gas. +It is of the down-draft type, with an available burning space of about 8 +cu. ft. (Fig. 9). For heavier ware and the study of the fire behavior of +clay products under conditions approaching those of practice, a round +down-draft kiln, with an inside diameter of 6 ft., is installed. About +13 ft. above the floor level, and supported by iron beams, there is a +flue parallel to the long side of the structure. This flue conducts the +gases of the kilns to the stack, which is symmetrically located with +reference to the kiln house. Natural gas is the principal fuel. In +addition to these kilns, a small muffle furnace, fired with petroleum, +is provided for the determination of melting points, and an electric +carbon resistance furnace, with an aluminum muffle for high-temperature +work. For crucible-fusion work, a gas-fired pot furnace is installed. + + [Illustration: Fig. 7. + + CLAY-DRYING OVEN] + +Along the north wall, bins are provided for the storage of fuel, clay, +sand, and other kiln supplies. There are two floor drainage sinks, and +electric current, steam, water, and compressed air, are provided. + + [Illustration: Fig. 8. + + DRYING CLOSETS FOR CERAMICS] + +_Results of the Work._--More than 39,300 separate test pieces have been +made at the structural-materials testing laboratory. In connection with +the study of these, 86,000 tests and nearly 14,000 chemical analyses +have been made. Of these tests more than 13,600 have been of the +constituent materials of concrete, including tensile tests of cement +briquettes, compression tests of cylinders and cubes, and transverse +tests of various specimens. + +Nearly 1,200 beams of concrete or reinforced concrete, each 13 ft. long +and 8 by 11 in. in cross-section, have been made, and, in connection +with the investigation of the behavior of these beams, nearly 3,000 +tests have been made. Nearly 900 of these beams, probably more than +double the entire number made in other laboratories in the United +States, during a period of more than 15 years, have been tested. + +In the section of building blocks, 2,200 blocks have been tested, +including, with auxiliary pieces, more than 4,500 tests; also, more than +900 pieces of concrete have been tested for permeability and shear. The +physical tests have numbered 14,000; tests of steel for reinforcement, +3,800; and 550 tests to determine fire-resistive qualities of various +building materials, have been made on 30 special panels, and on +miscellaneous pieces. + + [Illustration: Fig. 9. + + DOWN-DRAFT KILN] + +The tests of the permeability of cement mortars and concretes, and of +water-proofing and damp-proofing materials, have numbered 3,470. + +The results of the work of the Structural Materials Division have +already appeared in preliminary bulletins, as follows: No. 324, "San +Francisco Earthquake and Fire of April 18, 1906, and Their Effects on +Structures and Structural Materials"; No. 329, "Organization, Equipment, +and Operation of the Structural-Materials Testing Laboratories at St. +Louis, Mo."; No. 331, "Portland Cement Mortars and Their Constituent +Materials" (based on nearly 25,000 tests); No. 344, "Strength of +Concrete Beams" (based on tests of 108 beams); No. 370, "Fire-Resistive +Properties of Various Building Materials"; No. 387, "The Colloid Matter +of Clay and its Measurements." A bulletin on the results of tests of +reinforced concrete beams, one on the manufacture and chemistry of lime, +and one on drying tests of brick, are in course of publication. + + +FUEL INVESTIGATIONS. + +The scope of the fuel investigations has been planned to conform to the +provisions of the Act of Congress which provides for analyzing and +testing coals, lignites, and other mineral fuel substances belonging to +the United States, or for the use of the United States Government, and +examinations for the purpose of increasing the general efficiency or +available supply of the fuel resources in the United States. + +In conformity with this plan, the investigations inaugurated at St. +Louis had for their initial object the analyzing and testing of the +coals of the United States, using in this work samples of from 1 to 3 +carloads, collected with great care from typical localities in the more +important coal fields of the country, with a view to determining the +relative values of those different fuels. In the work at Norfolk, during +1907, this purpose was modified to the extent of keeping in view +relative fuel efficiencies for naval purposes. The tests at Denver have +been on coal from Government land or from land contiguous thereto, and +are conducted solely with a view to perfecting methods of coking this +coal by prior washing and by manipulation in the process of coking. + +Three general lines of inquiry are embodied in the plan of investigation +undertaken and contemplated by the Technologic Branch, after conference +and with the advice and approval of the Advisory Board: 1. The +ascertainment of the best mode of utilizing any fuel deposit owned or to +be used by the Government, or the fuel of any extensive deposit as a +whole, by conducting a more thorough investigation into its combustion +under steam boilers, conversion into producer gas, or into coke, +briquettes, etc. 2. The prevention of waste, through the study of the +possibility of improvement in the methods of mining, shipping, +utilizing, etc. 3. The inspection and analysis of coal and lignite +purchased under specification for the use of the Government, to +ascertain its heating value, ash, contained moisture, etc. + +The first general line of work concerns the investigation and testing of +the fuel resources of the United States, and especially those belonging +to the Federal Government, to determine a more efficient and more +economical method of utilizing the same. This work has developed along +the following lines: + +The collection of representative samples for chemical analysis, and +calorimeter tests by a corps of skilled mine samplers, from the mines +selected as typical of extensive deposits of coal in a given field or +from a given bed of coal; and the collection from the same mines of +larger samples of from 1 to 3 carloads, shipped to the testing station +for tests in boiler furnaces, gas producers, etc., as a check on the +analysis and calorimeter tests; + +The testing of each coal received to determine the most efficient and +least wasteful method of use in different furnaces suitable for public +buildings or power plants or ships of the Government; + +The testing of other portions of the same shipment of coal in the gas +producer, for continuous runs during periods of a few days up to several +weeks, in order to determine the availability of this fuel for use in +such producers, and the best method of handling it, to determine the +conditions requisite to produce the largest amount of high-grade gas +available for power purposes; + +The testing of another portion of the same coal in a briquette machine +at different pressures and with different percentages and kinds of +binder, in order to determine the feasibility of briquetting the slack +or fine coal. Combustion tests are then made of these briquettes, to +determine the conditions under which they may be burned advantageously; + +Demonstrations, on a commercial scale, of the possibility of producing +briquettes from American lignites, and the relative value of these for +purposes of combustion as compared with the run-of-mine coal from which +the briquettes are made; + +The finding of cheaper binders for use in briquetting friable coals not +suited for coking purposes; + +Investigations into the distribution, chemical composition, and +calorific value of the peat deposits available in those portions of the +United States where coal is not found, and the preparation of such peat +for combustion, by drying or briquetting, to render it useful as a local +substitute for coal; + +Investigations into the character of the various petroleums found +throughout the United States, with a view to determining their calorific +value, chemical composition, and the various methods whereby they may be +made most economically available for more efficient use as power +producers, through the various methods of combustion; + +Investigations and tests into the relative efficiency, as power +producers in internal-combustion engines, of the heavier distillates of +petroleum, as well as of kerosene and gasoline, in order to ascertain +the commercial value and relative efficiency of each product in the +various types of engines; + +Investigations into the most efficient methods of utilizing the various +coals available throughout the United States for heating small public +buildings, army posts, etc., in order that these coals may be used more +economically than at present; + +Investigative studies into the processes of combustion within boiler +furnaces and gas producers to ascertain the temperatures at which the +most complete combustion of the gases takes place, and the means whereby +such temperatures may be produced and maintained, thus diminishing the +loss of values up the smokestack and the amount of smoke produced; + +Investigations and tests into the possibilities of coking coals which +have hitherto been classed as non-coking, and the making of comparative +tests of all coals found in the United States, especially those from the +public lands of the West; + +Investigations, by means of washing in suitable machines, to determine +the possibility of improving the quality of American coals for various +methods of combustion, and with a view to making them more available for +the production of coke of high-grade metallurgical value, as free as +possible from sulphur and other injurious substances. + +At each stage of the process of testing, samples of the coal have been +forwarded to the chemical laboratory for analyses; combustion +temperatures have been measured; and samples of gas collected from +various parts of the combustion chambers of the gas producers and boiler +furnaces have been analyzed, in order that a study of these data may +throw such light on the processes of combustion and indicate such +necessary changes in the apparatus, as might result in larger economies +in the use of coal. + +The second line of investigation concerns the methods of mining and +preparing coal for the market, and the collection of mine samples of +coal, oil, etc., for analysis and testing. It is well known that, under +present methods of mining, from 10 to 75% of any given deposit of coal +is left underground as props and supports, or as low-grade material, or +in overlying beds broken up through mining the lower bed first. An +average of 50% of the coal is thus wasted or rendered valueless, as it +cannot be removed subsequently because of the caving or falling in of +the roofs of abandoned galleries and the breaking up of the adjoining +overlying beds, including coal, floor, and roof. + +The investigations into waste in mining and the testing of the waste, +bone, and slack coal in gas producers, as briquettes, etc., have, for +their purpose, the prevention of this form of waste by demonstrating +that these materials, now wasted, may be used profitably, by means of +gas producers and engines, for power purposes. + +The third general line of investigation concerns the inspection and +sampling of fuel delivered to the Government under purchase contracts, +and the analyzing and testing of the samples collected, to determine +their heating value and the extent to which they may or may not comply +with the specifications under which they are purchased. The coal +delivered at the public buildings in the District of Columbia is sampled +by special representatives of the Technologic Branch of the Survey. The +taking of similar samples at public buildings and posts throughout the +United States, and the shipment of the samples in hermetically sealed +cans or jars to the chemical laboratory at Washington, is for the most +part looked after by special officers or employees at each place. These +purchases are made, to an increasing extent, under specifications which +provide premiums for coal delivered in excess of standards, and +penalties for deliveries below standards fixed in the specifications. +The standard for bituminous coals is based mainly on the heat units, +ash, and sulphur, while that for anthracite coal is based mainly on the +percentage of ash and the heat units. + +In connection with all these lines of fuel testing, certain research +work, both chemical and physical, is carried on to determine the true +composition and properties of the different varieties of coal, the +changes in the transformation from peat to lignite, from lignite to +bituminous coal, and from bituminous to anthracite coal, and the +chemical and physical processes in combustion. Experiments are conducted +concerning the destructive distillation of fuels; the by-products of +coking processes; the spontaneous combustion of coal; the storage of +coal, and the loss in value in various methods of storing; and kindred +questions, such as the weathering of coal. These experiments may yield +valuable results through careful chemical research work supplemented by +equally careful observations in the field. + +_Inspection and Mine Sampling._--In the Geological Survey Building, at +Washington, coal purchased for Government use on a guaranteed-analysis +or heat-value basis, is inspected and sampled. + +Some of the employees on this work are constantly at the mines taking +samples, or at public works inspecting coal for Government use, while +others are stationed at Washington to look after the deliveries of coal +to the many public buildings, and to collect and prepare samples taken +from these deliveries for analysis, as well as to prepare samples +received from public works and buildings in other parts of the country. + + [Illustration: Fig. 10. + + COAL-SAMPLING ROOM, GEOLOGICAL SURVEY, WASHINGTON, D.C.] + +The preparation of these samples is carried on in a room in the basement +of the building, where special machinery has been installed for this +work. Fig. 10 shows a plan of this room and the arrangement of the +sampling and crushing machinery. + +The crushing of the coal produces great quantities of objectionable +dust, and to prevent this dust from giving trouble outside the sampling +room, the wooden partitions on three sides of the room (the fourth side +being a masonry wall) are completely covered on the outside with +galvanized sheet iron. The only openings to the room are two doors, +which are likewise covered with sheet iron, and provided with broad +flanges of the same material, in order to seal effectually the openings +when the doors are shut. Fresh air is drawn into the room by a fan, +through a pipe leading to the outer air. A dust-collecting system which +carries the coal dust and spent air from the room, consists of an +arrangement of 8-in. and 12-in. pipes leading from hoods, placed over +the crushing machines, to the main furnace stack of the building. The +draft in this stack draws all the dust from the crushers directly +through the hoods to the main pipe, where most of it is deposited. + +The equipment of the sampling room consists of one motor-driven, baby +hammer crusher, which has a capacity of about 1 ton per hour and crushes +to a fineness of -in. mesh; one adjustable chipmunk jaw crusher, for 5- +and 10-lb. samples; one set of 4 by 7-in. rolls, crushing to 60 mesh, +for small samples; one large bucking board, and several different sizes +of riffle samplers for reducing samples to small quantities. The small +crushers are belted to a shaft driven by a separate motor from that +driving the baby crusher. + +In conducting the inspection of departmental purchases of coal in +Washington, the office is notified whenever a delivery of coal is to be +made at one of the buildings, and an inspector is sent, who remains +during the unloading of the coal. He is provided with galvanized-iron +buckets having lids and locks; each bucket holds about 60 lb. of coal. +In these buckets he puts small quantities of the coal taken from every +portion of the delivery, and when the delivery has been completed, he +locks the buckets and notifies the office to send a wagon for them. The +buckets are numbered consecutively, and the inspector makes a record of +these numbers, the date, point of delivery, quality of coal delivered, +etc. The buckets are also tagged to prevent error. He then reports to +the office in person, or by telephone, for assignment to another point +in the city. All the samples are delivered to the crushing room in the +basement of the Survey Building, to be prepared for analysis.[11] + +Samples taken from coal delivered to points outside of Washington are +taken by representatives of the department for which the coal is being +purchased, according to instructions furnished them, and, from time to +time, the regular inspectors are sent to see that these instructions are +being complied with. These samples are crushed by hand, reduced to about +2 lb. at the point where they are taken, and sent to Washington, in +proper air-tight containers, by mail or express, accompanied by +appropriate descriptions. + +Each sample is entered in the sample record book when received, and is +given a serial number. For each contract a card is provided giving +information relative to the contract. On this card is also entered the +serial number of each sample of coal delivered under that contract. + +After the samples are recorded, they are sent to the crushing room, +where they are reduced to the proper bulk and fineness for analysis. +They are then sent, in rubber-stoppered bottles, accompanied by blank +analysis report cards and card receipts, one for each sample, showing +the serial numbers, to the fuel laboratory for analysis. The receipt +card for each sample is signed and returned to the inspection office, +and when the analysis has been made, the analysis report card showing +the result is returned. This result is entered at once on the contract +card, and when all analyses have been received, covering the entire +delivery of coal, the average quality is calculated, and the results are +reported to the proper department. + +The matter of supplying the Pittsburg plant with fuel for test purposes +is also carried on from the Washington office. Preliminary to a series +of investigations, the kinds and amounts of coal required are decided +on, and the localities from which these coals are to be obtained are +determined. Negotiations are then opened with the mine owners, who, in +most cases, generously donate the coal. When the preliminaries have been +arranged, an inspector is sent to the mine to supervise the loading and +shipment of the coal. This inspector enters the mine and takes, for +chemical analysis, small mine samples which are sent to the laboratory +at Pittsburg in metal cans by mail, accompanied by proper identification +cards. The results of the analysis are furnished to the experts in +charge at the testing plant, for their information and guidance in the +investigations for which the coal was shipped. + +All samples for testing purposes are designated consecutively in the +order of shipment, "Pittsburg No. 1," "Pittsburg No. 2," etc. A complete +record of all shipments is kept on card forms at the Pittsburg plant, +and a duplicate set of these is on file in the inspection office at +Washington. + +_Analysis of Fuels._--The routine analyses of fuel used in the +combustion tests at Pittsburg, and of the gases resulting from +combustion or from explosions in the testing galleries, or sampled in +the mines, are made in Building No. 21.[12] A small laboratory is also +maintained on the second floor of the south end of Building No. 13, for +analyses of gases resulting from combustion in the producer-gas plant, +and from explosions in Galleries Nos. 1 and 2, etc. From four to six +chemists are continually employed in this laboratory (in 8-hour shifts), +during prolonged gas-producer tests, and three chemists are also +employed in analyzing gases relating to mine explosions. + +In addition to these gas analyses, there are also made in the main +laboratory, analyses and calorific tests of all coal samples collected +by the Geological Survey in connection with its land-classification work +on the coal lands of the Western States. Routine analyses of mine, car, +and furnace samples of fuels for testing, before and after washing and +briquetting, before coking and the resultant coke, and extraction +analyses of binders for briquettes, etc., are also made in this +laboratory. + +The fuel-testing laboratory at Washington is equipped with three Mahler +bomb calorimeters and the necessary balances and chemical equipment +required in the proximate analysis of coal. More than 650 deliveries of +coal are sampled each month for tests, representing 50,000 tons +purchased per month, besides daily deliveries, on ship-board, of 550,000 +tons of coal for the Panama Railroad. The data obtained by these tests +furnish the basis for payment. The tests cover deliveries of coal to the +forty odd bureaus, and to the District Municipal buildings in +Washington; to the arsenals at Watertown, Mass., Frankford, Pa., and +Rock Island, Ill.; and to a number of navy yards, through the Bureau of +Yards and Docks; to military posts in various parts of the country; for +the Quartermaster-General's Department; to the Reclamation Service; to +Indian Agencies and Soldiers' Homes; to several lighthouse districts; +and to the superintendents of the various public buildings throughout +the United States, through the Treasury Department; etc. During 1909, +the average rate of reporting fuel samples was 540 per month, requiring, +on an average, six determinations per sample, or about 3,240 +determinations per month. + +_Fuel-Research Laboratories._--Smaller laboratories, occupying, on the +average, three rooms each, are located in Building No. 21. One is used +for chemical investigations and calorific tests of petroleum collected +from the various oil fields of the United States; another is used for +investigations relative to the extraction of coal and the rapidity of +oxidization of coals by standard solutions of oxidizing agents; and +another is occupied with investigations into the destructive +distillation of coal. The researches under way show the wide variation +in chemical composition and calorific value of the various crude oils, +indicate the possibility of the extraction of coal constituents by +solvents, and point to important results relative to the equilibrium of +gases at high temperatures in furnaces and gas producers. The +investigations also bear directly on the coking processes, especially +the by-product process, as showing the varying proportion of each of the +volatile products derivable from types of coals occurring in the various +coal fields of the United States, the time and temperature at which +these distillates are given off, the variation in quality and quantity +of the products, according to the conditions of temperature, and, in +addition, explain the deterioration of coals in storage, etc. + + [Illustration: Fig. 11. + + PLAN OF CONSTRUCTION DETAILS OF METAL HOOD] + +At the Washington office, microscopic investigations into the life +history of coal, lignite, and peat are being conducted. These +investigations have already progressed far enough to admit of the +identification of some of the botanical constituents of the older peats +and the younger lignites, and it is believed that the origin of the +older lignites, and even of some of the more recent bituminous coals, +may be developed through this examination. + +In the chemical laboratories, in Building No. 21, the hoods (Figs. 11 +and 12) are of iron, with a brick pan underneath. They are supported on +iron pipes, as are most of the other fixtures in the laboratories in +this building. The hood proper is of japanned, pressed-iron plate, No. +22 gauge, the same material being used for the boxes, slides, and bottom +surrounding the hood. The sash is hung on red copper pulleys, and the +corners of the hood are reinforced with pressed, japanned, riveted plate +to which the ventilating pipe is riveted. + + [Illustration: Fig. 12. + + ELEVATION OF CONSTRUCTION DETAILS OF METAL HOOD] + +There is some variety in the cupboards and tables provided in the +various laboratories, but, in general, they follow the design shown in +Fig. 13. The table tops, 12 ft. long, are of clear maple in full-length +pieces, 7/8 in. thick and 2-5/8 in. wide, laid on edge and drilled at +18-in. intervals for bolts. These pieces are glued and drawn together by +the bolts, the heads of which are countersunk. The tops, planed off, +sanded, and rounded, are supported on pipe legs and frames of 1 by +1-in. galvanized-iron pipe with screw flanges fitting to the floor and +top. Under the tops are drawers and above them re-agent shelves. Halfway +between the table top and the floor is a wire shelf of a frame-work of +No. 2 wire interlaced with No. 12 weave of 5/8-in. square mesh. + +Certain of the tables used in the laboratory are fitted with cupboards +beneath and with drawers, and, in place of re-agent stands, +porcelain-lined sinks are sunk into them. These tables follow, in +general style and construction, the re-agent tables. The tables used in +connection with calorimeter determinations are illustrated in Fig. 14. +The sinks provided throughout these laboratories are of standard +porcelain enamel, rolled rim, 18 by 13 in., with enameled back, over a +sink and drain board, 24 in. long on the left side, though there are +variations from this type in some instances. + +The plumbing includes separate lines of pipe to each hood and table; one +each for cold water, steam at from 5 to 10 lb. pressure, compressed air, +natural gas, and, in some cases, live steam at a pressure of 60 lb. + +On each table is an exposed drainage system of 2-in. galvanized-iron +pipe, in the upper surface of which holes have been bored, through which +the various apparatus drain by means of flexible connections of glass or +rubber. These pipes and the sinks, etc., discharge into main drains, +hung to the ceiling of the floor beneath. These drains are of wood, +asphaltum coated, with an inside diameter ranging from 3 to 6 in., and +at the proper grades to secure free discharge. These wooden drain-pipes +are made in short lengths, strengthened by a spiral wrapping of metal +bands, and are tested to a pressure of 40 lb. per sq. in. Angles are +turned and branches connected in 4- and 6-in. square headers. + + [Illustration: Fig. 13. + + PLAN OF CONSTRUCTION DETAILS OF REAGENT TABLES BUILDING 21.] + + + [Illustration: Fig. 14. + + CONSTRUCTION DETAILS OF CALORIMETER TABLES] + +The entire building is ventilated by a force or blower fan in the +basement, and by an exhaust fan in the attic with sufficient capacity to +insure complete renewal of air in each laboratory once in 20 min. + +The blower fan is placed in the center of the building, on the ground +floor, and is 100 in. in diameter. Its capacity is about 30,000 cu. ft. +of air per min., and it forces the air, through a series of pipes, into +registers placed in each of the laboratories. + +The exhaust fan, in the center of the attic, is run at 550 rev. per +min., and has a capacity of 22,600 cu. ft. of air per min. It draws the +air from each of the rooms below, as well as from the hoods, through a +main pipe, 48 in. in diameter. + +_Steaming and Combustion Tests._--The investigations included under the +term, fuel efficiency, relate to the utilization of the various types of +fuels found in the coal and oil fields, and deal primarily with the +combustion of such fuels in gas producers, in the furnaces of steam +boilers, in locomotives, etc., and with the efficiency and utilization +of petroleum, kerosene, gasoline, etc., in internal-combustion engines. +This work is under the general direction of Mr. R. L. Fernald, and is +conducted principally in Buildings Nos. 13 (Plate XVII) and 21. + +For tests of combustion of fuels purchased by the Government, the +equipment consists of two Heine, water-tube boilers, each of 210 h.p., +set in Building No. 13. One of these boilers is equipped with a Jones +underfeed stoker, and is baffled in the regular way. At four points in +the setting, large pipes have been built into the brick wall, to permit +making observations on the temperature of the gas, and to take samples +of the gas for chemical analysis. + +The other boiler is set with a plain hand-fired grate. It is baffled to +give an extra passage for the gases (Fig. 15). Through the side of this +boiler, at the rear end, the gases from the long combustion chamber +(Plate XVIII) enter and take the same course as those from the +hand-fired grate. Both the hand-fired grate and the long combustion +chamber may be operated at the same time, but it is expected that +usually only one will be in operation. A forced-draft fan has been +installed at one side of the hand-fired boiler, to provide air pressure +when coal is being burned at high capacity. This fan is also connected +in such a way as to furnish air for the long combustion chamber when +desired. A more complete description of the boilers may be found in +Professional Paper No. 48, and Bulletin No. 325 of the U.S. Geological +Survey, in which the water-measuring apparatus is also described.[13] + +On account of the distance from Building No. 21 to the main group of +buildings, it was considered inadvisable to attempt to furnish steam +from Building No. 13 to Building No. 21, either for heating or power +purposes. In view, moreover, of the necessity of installing various +types and sizes of house-heating boilers, on account of tests to be made +thereon in connection with these investigations, it was decided to +install these boilers in the lower floor of Building No. 21, where they +could be utilized, not only in making the necessary tests, but in +furnishing heat and steam for the building and the chemical laboratories +therein. + + [Illustration: Fig. 15. + + SETTING FOR 210-HORSE POWER, HAND-FIRED BOILERS] + +In addition to the physical laboratory on the lower floor of Building +No. 21, and the house-heating boiler plant with the necessary coal +storage, there are rooms devoted to the storage of heavy supplies, +samples of fuels and oils, and miscellaneous commercial apparatus. One +room is occupied by the ventilating fan and one is used for the +necessary crushers, rolls, sizing screens, etc., required in connection +with the sampling of coal prior to analysis. + +The Quartermaster's Department having expressed a wish that tests be +made of the heating value and efficiency of the various fuels offered +that Department, in connection with the heating of military posts +throughout the country, three house-heating boilers were procured which +represent, in a general way, the types and sizes used in a medium-sized +hospital or other similar building, and in smaller residences (Fig. 2, +Plate XVI). The larger apparatus is a horizontal return-tubular boiler, +60 in. in diameter, 16 ft. long, and having fifty-four 4-in. tubes.[14] + +In order to determine whether such a boiler may be operated under +heating conditions without making smoke, when burning various kinds of +coal, it has been installed in accordance with accepted ideas regarding +the prevention of smoke. A fire-brick arch extends over the entire grate +surface and past the bridge wall. A baffle wall has been built in the +combustion chamber, which compels the gases to pass downward and to +divide through two openings before they reach the boiler shell. +Provision has been made for the admission of air at the front of the +furnace, underneath the arch, and at the rear end of the bridge wall, +thus furnishing air both above and below the fire. It is not expected +that all coals can be burned without smoke in this furnace, but it is +desirable to determine under what conditions some kinds of coals may be +burned without objectionable smoke.[15] + +For sampling the gases in the smokebox of the horizontal return-tubular +boiler, a special flue-gas sampler was designed, in order to obtain a +composite sample of the gases escaping from the boiler. + +The other heaters are two cast-iron house-heating boilers. One can +supply 400 sq. ft. of radiation and the other about 4,000 sq. ft. They +were installed primarily for the purpose of testing coals to determine +their relative value when burned for heating purposes. They are piped to +a specially designed separator, and from this to a pressure-reducing +valve. Beyond this valve an orifice allows the steam to escape into the +regular heating mains. This arrangement makes it possible to maintain a +practically constant load on the boilers. + + [Illustration: PLATE XVIII. + + Fig. 1.--Long Combustion Chamber. + + Fig. 2.--Gas Sampling Apparatus, Long Combustion Chamber.] + +There is a fourth boiler, designed and built for testing purposes by the +Quartermaster's Department. This is a tubular boiler designed on the +lines of a house-heating boiler, but for use as a calorimeter to +determine the relative heat value of different fuels reduced to the +basis of a standard cord of oak wood. + +A series of research tests on the processes of combustion is being +conducted in Building No. 13, by Mr. Henry Kreisinger. These tests are +being made chiefly in a long combustion chamber (Figs. 16 and 17, and +Figs. 1 and 2, Plate XVIII), which is fed with coal from a Murphy +mechanical stoker, and discharges the hot gases at the rear end of the +combustion chamber, into the hand-fired Heine boiler. The walls and roof +of this chamber are double; the inner wall is 9 in. thick, of +fire-brick; the outer one is 8 in. thick, and is faced with red pressed +brick. Between the walls of the sides there is a 2-in. air space, and +between them on the roof a 1-in. layer of asbestos paste is placed. The +inner walls and roof have three special slip-joints, to allow for +expansion. The floor is of concrete, protected by a 1-in. layer of +asbestos board, which in turn is covered by a 3-in. layer of earth; on +top of this earth there is a 4-in. layer of fire-brick (not shown in the +drawings). + + [Illustration: Fig. 16. + + CROSS-SECTIONS OF CHAMBER AND OF FURNACE, LONG COMBUSTION CHAMBER] + +Inasmuch as one of the first problems to be attacked will be the +determination of the length of travel and the time required to complete +combustion in a flame in which the lines of stream flow are nearly +parallel, great care was taken to make the inner surfaces of the tunnel +smooth, and all corners and hollows are rounded out in the direction of +travel of the gases. + +Provision is made, by large peep-holes in the sides, and by smaller +sampling holes in the top, for observing the fuel bed at several points +and also the flame at 5-ft. intervals along the tunnel. Temperatures and +gas samples are taken simultaneously at a number of points through these +holes, so as to determine, if possible, the progress of combustion +(Fig. 1, Plate XVIII). + +About twenty thermo-couples are embedded in the walls, roof, and floor, +some within 1 in. of the inside edge of the tunnel walls, and some in +the red pressed brick near the outer surface, the object of which is to +procure data on heat conduction through well-built brick walls[16] (Fig. +2, Plate XVIII). + +In order to minimize the leakage of air through the brickwork, the +furnace and tunnel are kept as nearly as possible at atmospheric +pressure by the combined use of pressure and exhausting fans. +Nevertheless, the leakage is determined periodically as accurately as +possible. + +At first a number of tests were run to calibrate the apparatus as a +whole, all these preliminary tests being made on cheap, carefully +inspected, uniform screenings from the same seam of the same mine near +Pittsburg. Later tests will be run with other coals of various volatile +contents and various distillation properties. + +It is anticipated that the progress of the tests may suggest changes in +the construction or operation of this chamber. It is especially +contemplated that the section of the chamber may be narrowed down by +laying sand in the bottom and fire-brick thereon; also that baffle walls +may be built into various portions of it, and that cooling surfaces with +baffling may be introduced. In addition to variations in the tests, due +to changes in construction in the combustion chamber, there will be +variations in the fuels tested. Especial effort will be made to procure +fuels ranging in volatile content from 15 to 27 and to 40%, and those +high in tar and heavy hydro-carbons. It is also proposed to vary the +conditions of testing by burning at high rates, such as at 15, 20, and +30 lb. per ft. of grate surface, and even higher. Records will be kept +of the weight of coal fired and of each firing, of the weight of ash, +etc.; samples of coal and of ash will be taken for chemical and physical +analysis, as well as samples of the gas, and other essential data. These +records will be studied in detail. + + [Illustration: Fig. 17. + + LONGITUDINAL SECTIONS OF LONG COMBUSTION CHAMBER] + +A series of heat-transmission tests undertaken two years ago, is being +continued on the ground floor of Building No. 21, on modified apparatus +reconstructed in the light of the earlier experiments by Mr. W. T. Ray. +The purpose of the tests on this apparatus has been to determine some of +the laws controlling the rate of transmission of heat from a hot gas to +a liquid and _vice versa_, the two being on the opposite sides of a +metal tube. + +It appears that four factors determine the rate of heat impartation from +the gas to any small area of the metal[17]: + + [Footnote 17: The assumption is made that a metal tube free from scale + will remain almost as cool as the water; actual measurements with + thermo-couples have indicated the correctness of this assumption in + the majority of cases.] + + (1).--The temperature difference between the body of the gas and the + metal; + + (2).--The weight of the gas per cubic foot, which is proportional to + the number of molecules in any unit of volume; + + (3).--The bodily velocity of the motion of the gas parallel to any + small area under consideration; and (probably), + + (4).--The specific heat of the gas at constant pressure. + +The apparatus consists of an electric resistance furnace containing +coils of nickel wire, a small (interchangeable) multi-tubular boiler, +and a steam-jet apparatus for reducing the air pressure at the exit end, +so as to cause a flow of air through the boiler. A surface condenser was +attached to the boiler's steam outlet, the condensed steam being weighed +as a check on the feed-water measurements. A number of thermometers and +thermo-couples were used to obtain atmospheric-air temperature, +temperatures of the air entering and leaving the boilers, and feed-water +temperature. + +The apparatus is now being reconstructed with appliances for measuring +the quantity of air entering the furnace, and an automatic +electric-furnace temperature regulator. + + [Illustration: PLATE XIX. + + Fig. 1.--Gas Producer, Economizer, and Wet Scrubber. + + Fig. 2.--Producer Gas: Dry Scrubber and Gas Holder.] + +Three sizes of boiler have been tested thus far, the dimensions being as +given in Table 4. + +Each of the three boilers was tested at several temperatures of entering +air, up to 1,500 Fahr., about ten tests being made at each temperature. +It is also the intention to run, on these three boilers, about eight +tests at temperatures of 1,800, 2,100 and 2,400 Fahr., respectively. +A bulletin on the work already done, together with much incidental +matter, is in course of preparation.[18] + + TABLE 4.--Dimensions of Boilers Nos. 1, 2, and 3. + + ------------------------------------+--------+--------+-------- + Items. | Boiler | Boiler | Boiler + | No. 1. | No. 2. | No. 3. + ------------------------------------+--------+--------+-------- + Distance, outside to outside of | | | + boiler heads, in inches | 8.28 | 8.28 | 16.125 + Actual outside diameter of flues, | 0.252 | 0.313 | 0.252 + in inches | | | + Actual inside diameter of flues, | 0.175 | 0.230 | 0.175 + in inches | | | + Number of flues (tubes) | 10 | 10 | 10 + ------------------------------------+--------+--------+-------- + +The work on the first three boilers is only a beginning; preparations +are being made to test eight more multi-tubular boilers of various +lengths and tube diameters, under similar conditions. Because of the +experience already obtained, it will be necessary to make only eight +tests at each initial air temperature. + +When the work on multi-tubular boilers is completed, water-tube boilers +will be taken up, for which a fairly complete outline has been prepared. +This second or water-tube portion of the investigation is really of the +greater scientific and commercial interest, but the multi-tubular +boilers were investigated first because the mathematical treatment is +much simpler. + +_Producer-Gas Tests._--The producer-gas plant at the Pittsburg testing +station is in charge of Mr. Carl D. Smith, and has been installed for +the purpose of testing low-grade fuel, bone coal, roof coal, mine +refuse, and such material as is usually considered of little value, or +even worthless for power purposes. The gas engine, gas producer, +economizer, wet scrubber (Fig. 1, Plate XIX), and accessories, are in +Building No. 13, and the dry scrubber, gas-holder, and water-cooling +apparatus are immediately outside that building (Fig. 2, Plate XIX). + +At present immense quantities of fuel are left at the mines, in the form +of culm and slack, which, in quality, are much below the average output. +Such fuel is considered of little or no value, chiefly because there is +no apparatus in general use which can burn it to good advantage. The +heat value of this fuel is often from 50 to 75% of that of the fuel +marketed, and if not utilized, represents an immense waste of natural +resources. Large quantities of low-grade fuel are also left in the +mines, simply because present conditions do not warrant its extraction, +and it is left in such a way that it will be very difficult, if not +practically impossible, for future generations to take out such fuel +when it will be at a premium. Again, there are large deposits of +low-grade coal in regions far remote from the sources of the present +fuel supply, but where its successful and economic utilization would be +a boon to the community and a material advantage to the country at +large. The great importance of the successful utilization of low-grade +fuel is obvious. Until within very recent years little had been +accomplished along these lines, and there was little hope of ever being +able to use these fuels successfully. + +The development of the gas producer for the utilization of ordinary +fuels,[19] however, indicates that the successful utilization of +practically all low-grade fuel is well within the range of possibility. +It is notable that, although all producer-gas tests at the Government +testing stations, at St. Louis and Norfolk, were made in a type of +producer[20] designed primarily for a good grade of anthracite coal, the +fuels tested included a wide range of bituminous coals and lignites, and +even peat and bone coal, and that, in nearly every test, little serious +difficulty was encountered in maintaining satisfactory operating +conditions.[21] It is interesting to note that in one test, a bone coal +containing more than 45% of ash was easily handled in the producer, and +that practically full load was maintained for the regulation test period +of 50 hours.[22] + +It is not expected that all the fuels tested will prove to be of +immediate commercial value, but it is hoped that much light will be +thrown on this important problem. + + [Illustration: PLATE XX. + + Fig. 1.--Charging Floor of Gas Producer. + + Fig. 2.--European and American Briquettes.] + +The equipment for this work consists of a single gas generator, rated at +150 h.p., and a three-cylinder, vertical gas engine of the same +capacity. The producer is a Loomis-Pettibone, down-draft, made by the +Power and Mining Machinery Company, of Cudahy, Wis., and is known as its +"Type C" plant. The gas generator consists of a cylindrical shell, 6 ft. +in diameter, carefully lined with fire-brick, and having an internal +diameter of approximately 4 ft. Near the bottom of the generator there +is a fire-brick grate, on which the fuel bed rests. The fuel is charged +at the top of the producer through a door (Fig. 1, Plate XX), which may +be left open a considerable time without affecting the operation of the +producer, thus enabling the operator to watch and control the fuel bed +with little inconvenience. As the gas is generated, it passes downward +through the hot fuel bed and through the fire-brick grate. This +down-draft feature "fixes," or makes into permanent gases, the tarry +vapors which are distilled from bituminous coal when it is first charged +into the producer. A motor-driven exhauster with a capacity of 375 cu. +ft. per min., draws the hot gas from the base of the producer through an +economizer, where the sensible heat of the gas is used to pre-heat the +air and to form the water vapor necessary for the operation of the +producer. The pre-heated air and vapor leave the economizer and enter +the producer through a passageway near the top and above the fuel bed. +From the economizer the gas is drawn through a wet scrubber where it +undergoes a further cooling and is cleansed of dirt and dust. After +passing the wet scrubber, the gas, under a light pressure, is forced, by +the exhauster, through a dry scrubber to a gas-holder with a capacity of +about 1,000 cu. ft. + +All the fuel used is carefully weighed on scales which are checked from +time to time by standard weights; and, as the fuel is charged into the +producer, a sample is taken for chemical analysis and for the +determination of its calorific power. The water required for the +generation of the vapor is supplied from a small tank carefully +graduated to pounds; this observation is made and recorded every hour. +All the water used in the wet scrubber is measured by passing it through +a piston-type water meter, which is calibrated from time to time to +insure a fair degree of accuracy in the measurement. Provision is made +for observing the pressure and temperature of the gas at various points; +these are observed and recorded every hour. + +From the holder the gas passes through a large meter to the vertical +three-cylinder Westinghouse engine, which is connected by a belt to a +175-kw., direct-current generator. The load on the generator is measured +by carefully calibrated switch-board instruments, and is regulated by a +specially constructed water rheostat which stands in front of the +building. + +Careful notes are kept of the engine operation; the gas consumption and +the load on the engine are observed and recorded every 20 min.; the +quantity of jacket water used on the gas engine, and also its +temperature entering and leaving the engine jackets, are recorded every +hour. Indicator cards are taken every 2 hours. The work is continuous, +and each day is divided into three shifts of 8 hours each; the length of +a test, however, is determined very largely by the character and +behavior of the fuel used. + +A preliminary study of the relative efficiency of the coals found in +different portions of the United States, as producers of illuminating +gas, has been nearly completed under the direction of Mr. Alfred H. +White, and a bulletin setting forth the results is in press.[23] + +_Tests of Liquid Fuels._--Tests of liquid fuels in internal-combustion +engines, in charge of Mr. R. M. Strong, are conducted in the engine-room +of Building No. 13. + +The various liquid hydro-carbon fuels used in internal-combustion +engines for producing power, range from the light refined oils, such as +naphtha, to the crude petroleums, and have a correspondingly wide +variation of physical and chemical properties. + +The most satisfactory of the liquid fuels for use in internal-combustion +engines, are alcohol and the light refined hydro-carbon oils, such as +gasoline. These fuels, however, are the most expensive in commercial +use, even when consumed with the highest practical efficiency, which, it +is thought, has already been attained, as far as present types of +engines are concerned. + +At present little is known as to how far many of the very cheap +distillates and crude petroleums can be used as fuel for +internal-combustion engines. It is difficult to use them at all, +regardless of efficiency. + +Gasoline is comparatively constant in quality, and can be used with +equal efficiency in any gasoline engine of the better grade. There are +many makes of high-grade gasoline engines, tests on any of which may be +taken as representative of the performance and action of gasoline in an +internal-combustion engine, if the conditions under which the tests were +made are clearly stated and are similar. + +Kerosene varies widely in quality, and requires special devices for its +use, but is a little cheaper than gasoline. It is possible that the +kerosene engine may be developed so as to permit it to take the place of +the smaller stationary and marine gasoline engines. This would mean +considerable saving in fuel cost to the small power user, who now finds +the liquid-fuel internal-combustion engine of commercial advantage. A +number of engines at present on the market use kerosene; some use only +the lighter grades and are at best comparatively less efficient than +gasoline engines. All these engines have to be adjusted to the grade of +oil to be used in order to get the best results. + +Kerosene engines are of two general types: the external-vaporizer type, +in which the fuel is vaporized and mixed with air before or as it is +taken into the cylinder; and the internal-vaporizer type, in which the +liquid fuel is forced into the cylinder and vaporized by contact with +the hot gases or heated walls of a combustion chamber at the head of the +cylinder. A number of special devices for vaporizing kerosene and the +lighter distillates have been tried and used with some success. Heat is +necessary to vaporize the kerosene as quickly as it is required, and the +degree of heat must be held between the temperature of vaporization and +that at which the oil will be carbonized. The vapor must also be +thoroughly and uniformly mixed with air in order to obtain complete +combustion. As yet, no reliable data on these limiting temperatures for +kerosene and similar oils have been obtained. No investigation has ever +been made of possible methods for preventing the oils from carbonizing +at the higher temperatures, and the properties of explosive mixtures of +oil vapors and air have not been studied. This field of engineering +laboratory research is of vital importance to the solution of the +kerosene-engine problem. + +Distillates or fuel oils and the crude oils are much the cheapest of the +liquid fuels, and if used efficiently in internal-combustion engines +would be by far the cheapest fuels available in many large districts. + +Several engine builders are developing kerosene vaporizers, which are +built as a part of the engine, or are adapted to each different engine, +as required to obtain the best results. Most of these vaporizers use the +heat and the exhaust gases to vaporize the fuel, but they differ greatly +in construction; some are of the retort type, and others are of the +float-feed carburetter type. To what extent the lower-grade fuel oils +can be used with these vaporizers is yet to be determined. + +There are only a few successful oil engines on the American market. The +most prominent of these represent specific applications of the principal +methods of internal vaporization, and all except one are of the hot-bulb +ignition type. It will probably be found that no one of the 4-stroke +cycle, or 2-stroke cycle, engines is best for all grades of oil, but +rather that each is best for some one grade. The Diesel engine is in a +class by itself, its cycle and method of control being somewhat +different from the others. + +An investigation of the comparative adaptability of gasoline and alcohol +to use in internal-combustion engines, consisting of more than 2,000 +tests, was made at the temporary fuel-testing plant of the Geological +Survey, at Norfolk, Va., in 1907. A detailed report of these tests is in +preparation.[24] A similar investigation of the comparative adaptability +of kerosenes has been commenced, with a view to obtaining data on their +economical use, leading up to the investigation of the comparative fuel +values of the cheaper distillates and crude petroleum, as before +discussed. + +_Washing and Coking Tests._--The investigations relating to the +preparation of low-grade coals, such as those high in ash or sulphur, by +processes that will give them a higher market value or increase their +efficiency in use, are in charge of Mr. A. W. Belden. They include the +washing and coking tests of coals, and the briquetting of slack and +low-grade coal and culm-bank refuse so as to adapt these fuels for +combustion in furnaces, etc. + +This work has been conducted in the washery and coking plant temporarily +located at Denver, Colo., and in Building No. 32 at the Pittsburg +testing station, where briquetting is in progress. The details of these +tests are set forth in the various bulletins issued by the Geological +Survey.[25] + +The washing tests are carried out in the following manner: As the raw +coal is received at the plant, it is shoveled from the railroad cars to +the hopper scale, and weighed. It then passes through the tooth-roll +crusher, where the lumps are broken down to a maximum size of 2 in. An +apron conveyor delivers the coal to an elevator which raises it to one +of the storage bins. As the coal is being elevated, an average sample +representing the whole shipment is taken. An analysis is made of this +sample of raw coal and float-and-sink tests are run to determine the +size to which it is necessary to crush before washing, and the +percentage of refuse with the best separation. From the data thus +obtained, the washing machines are adjusted so that the washing test is +made with full knowledge of the separations possible under varying +percentages of refuse. The raw coal is drawn from the bin and delivered +to a corrugated-roll disintegrator, where it is crushed to the size +found most suitable, and is then delivered by the raw-coal elevator to +another storage bin. The arrangement of the plant is such that the coal +may be first washed on a Stewart jig, and the refuse then delivered to +and re-washed on a special jig, or the refuse may be re-crushed and then +re-washed. + +When the coal is to be washed, it drops to the sluice box, where it is +mixed with the water and sluiced to the jigs. In drawing off the washed +coal, or when the uncrushed raw coal is to be drawn from a bin and +crushed for the washing tests, however, a gate just below the coal-flow +regulating gate is thrown in, and the coal falls into a central hopper +instead of into the sluice box. Ordinarily, this gate forms one side of +the vertical chute. The coal in this central hopper is carried by a +chute to the apron conveyor, and thence to the roll disintegrator, or, +in case it is washed coal, to a swing-hammer crusher. It will be noted +that coal, in this manner, can be drawn from a bin at the same time that +coal is being taken from another bin, and sluiced to the jigs for +washing, the two operations not interfering in the least. + +The washed coal, after being crushed and elevated to the top of the +building, is conveyed by a chute to the coke-oven larry, and is weighed +on the track scale, after which it is charged to the oven. The refuse is +sampled and weighed as it is wheeled to the dump pile, and from this +sample the analysis is made and a float-and-sink test run to determine +the "loss of good coal" in the refuse and to show the efficiency of the +washing test. + +The coking tests have been conducted in a battery of two beehive ovens, +one 7 ft. high and 12 ft. in diameter, the other, 6 ft. high and 12 ft. +in diameter. A standard larry with a capacity of 8 tons, and the +necessary scales for weighing accurately the coal charged and coke +produced, complete the equipment. The coal is usually run through a roll +crusher which breaks it to about -in. size, or through a Pennsylvania +hammer crusher. The fineness of the coals put through the hammer crusher +varies somewhat, but the average, taken from a large number of samples, +is as follows: Through 1/8-in. mesh, 100%; over 10-mesh, 31.43%; over +20-mesh, 24.29%; over 40-mesh, 22.86%; over 60-mesh, 10 per cent. The +results of the coking tests are set forth in detail in the various +publications issued on this subject.[26] + +Tests of coke produced in the illuminating-gas investigations before +referred to, and a study of commercial coking and by-product plants, are +included in these investigations. + +_Briquetting Investigations._--These investigations are in charge of Mr. +C. L. Wright, and are conducted in Building No. 32, which is of +fire-proof construction, having a steel-skeleton frame work, +reinforced-concrete floors, and 2-in. cement curtain walls, plastered on +expanded-metal laths. In this building two briquetting machines are +installed, one an English machine of the Johnson type, and the other a +German lignite machine of very powerful construction. + +The investigations include the possibility of making satisfactory +commercial fuels from lignite or low-grade coals which do not stand +shipment well, the benefiting of culm or slack coals which are wasted or +sold at unremunerative prices, and the possibility of improving the +efficiency of good coals. Some of the various forms of commercial +briquettes, American and foreign, are shown in Fig. 2, Plate XX. After +undergoing chemical analysis, the coal is elevated and fed to a storage +bin, whence it is drawn through a chute to a hopper on the weighing +scales. There it is mixed with varying percentages of different kinds of +binding material, and the tests are conducted so as to ascertain the +most suitable binder for each kind of fuel, which will produce the most +durable and weather-proof briquette at least cost, and the minimum +quantity necessary to produce a good, firm briquette. After weighing, +the materials to be tested are run through the necessary grinding and +pulverizing machines and are fed into the briquetting machines, whence +the manufactured briquettes are delivered for loading or storage. The +materials to be used in the German machine are also dried and cooled +again. + + [Illustration: PLATE XXI. + + Fig. 1.--Hand Briquetting Press. + + Fig. 2.--Coal Briquetting Machine.] + +The briquettes made at this plant are then subjected to physical tests +in order to determine their weathering qualities and their resistance to +abrasion; extraction tests and chemical analyses are also made. +Meanwhile other briquettes from the same lots are subjected to +combustion tests for comparison with the same coal not briquetted. These +tests are made in stationary boilers, in house-heating boilers, on +locomotives, naval vessels, etc., and the results, both of the processes +of manufacture, and of the tests, are published in various bulletins +issued by the Geological Survey.[27] + +The equipment includes storage bins for the raw coal, scales for +weighing, machines for crushing or cracking the pitch, grinders, +crushers, and disintegrators for reducing the coal to the desired +fineness, heating and mixing apparatus, presses and moulds for forming +the briquettes, a Schulz drier, and a cooling apparatus. + +There is a small experimental hand-briquetting press (Fig. 1, Plate XXI) +for making preliminary tests of the briquetting qualities of the various +coals and lignites. With this it is easily possible to vary the +pressure, heat, percentage and kind of binder, so as to determine the +best briquetting conditions for each fuel before subjecting it to +large-scale commercial tests in the big briquetting machines. + +This hand press will exert pressures up to 50 tons or 100,000 lb. per +sq. in., on a plunger 3 in. in diameter. This plunger enters a mould, +which can be heated by a steam jacket supplied with ordinary saturated +steam at a pressure of 125 lb., and compresses the fuel into a +briquette, 8 in. long, under the conditions of temperature and pressure +desired. + +The Johnson briquetting machine, which requires 25 h.p. for its +operation, exerts a pressure of about 2,500 lb. per sq. in., and makes +briquettes of rectangular form, 6 by 4 by 2 in., and having an +average weight of about 3 lb. The capacity of the machine (Fig. 2, +Plate XXI) is about 3.8 tons of briquettes per 8-hour day. + +Under the hopper on the scales for the raw material is a square wooden +reciprocal plunger which pushes the fuel into a hole in the floor at a +uniform rate. The pitch is added as uniformly as possible by hand, as +the coal passes this hole. Under this hole a horizontal screw conveyor +carries the fuel and pitch to the disintegrator, in front of which, in +the feeding chute, there is a powerful magnet for picking out any pieces +of iron which might enter the machine and cause trouble. + +The ground mixture is elevated from the disintegrator to a point above +the top of the upper mixer of the machine. At the base of this cylinder, +steam can be admitted by several openings to heat the material to any +desired temperature, usually from 180 to 205 Fahr. There, a plunger, +making 17 strokes per min., compresses two briquettes at each stroke. + +The German lignite-briquetting machine (Figs. 18 and 19) was made by the +Maschinenfabrik Buckau Actien-Gesellschaft, Magdeburg, Germany. Lignite +from the storage room on the third floor of the building is fed into one +end of a Schulz tubular drier (Fig. 1, Plate XXII), which is similar to +a multi-tubular boiler set at a slight angle from the horizontal, and +slowly revolved by worm and wheel gearing, the lignite passing through +the tubes and the steam being within the boiler. From this drier the +lignite passes through a sorting sieve and crushing rolls to a cooling +apparatus, which consists of four horizontal circular plates, about 13 +ft. in diameter, over which the dried material is moved by rakes. After +cooling, the material is carried by a long, worm conveyor to a large +hopper over the briquette press, and by a feeding box to the press (Fig. +2, Plate XXII). + +The press, which is of the open-mould type, consists of a ram and die +plates, the latter being set so as to make a tube which gradually tapers +toward the delivery end of the machine. The briquettes have a +cross-section similar to an ellipse with the ends slightly cut off; they +are about 1 in. thick and average about 1 lb. in weight (Fig. 2, Plate +XX). The press is operated by a direct connection with a steam engine of +150 h.p., the base of which is continuous with that of the press. The +exhaust steam from the engine is used to heat the driver. + +The plunger makes from 80 to 100 strokes per min., the pressure exerted +ranging from 14,000 to 28,000 lb. per sq. in., the capacity of the +machine being 1 briquette per stroke, or from 2 to 3 tons of completed +briquettes per hour. It is expected that no binder will be needed for +practically all the brown lignite briquetted by this machine, thus +reducing the cost as compared with the briquetting of coals, which +require from 5 to 7% of water-gas, pitch binder costing more than 50 +cents per ton of manufactured briquettes. + + [Illustration: Fig. 18. + + LONGITUDINAL-SECTION OF LIGNITE-BRIQUETTING PLANT] + + + [Illustration: Fig. 19. + + CROSS-SECTION OF LIGNITE-BRIQUETTING PLANT] + +_Peat Investigations._--Investigations into the distribution, +production, origin, nature, and uses of peat are being conducted by Mr. +C. A. Davis, and include co-operative arrangements with State Geological +Surveys and the Geologic Branch of the U.S. Geological Survey. These +organizations conduct surveys which include the mapping of the peat +deposits in the field, the determination of their extent and +limitations, the sampling of peat from various depths, and the +transmittal of samples to the Pittsburg laboratories for analysis and +test.[28] + +This work is co-ordinated in such a manner as to result in uniform +methods of procedure in studying the peat deposits of the United States. +The samples of peat are subjected to microscopic examination, in order +to determine their origin and age, and to chemical and physical tests at +the laboratories in Pittsburg, so as to ascertain the chemical +composition and calorific value, the resistance to compressive strains, +the ash and moisture content, drying properties, resistance to abrasion, +etc. Occasionally, large quantities of peat are disintegrated and +machined, and portions, after drying for different periods, are +subjected to combustion tests in steam boilers and to tests in the gas +producer, to ascertain their efficiency as power producers. + +_Results._--The full value of such investigations as have been described +in the preceding pages cannot be realized for many years; but, even +within the four years during which this work has been under way, certain +investigations have led to important results, some of which may be +briefly mentioned: + +The chemical and calorific determinations of coals purchased for the use +of the Government have resulted in the delivery of a better grade of +fuel without corresponding increase in cost, and, consequently, in +saving to the Government. Under this system, of purchasing its coal +under specifications and testing, the Government is getting more nearly +what it pays for and is paying for what it gets. These investigations, +by suggesting changes in equipment and methods, are also indicating the +practicability of the purchase of cheaper fuels, such as bituminous coal +and the smaller sizes of pea, buckwheat, etc., instead of the more +expensive sizes of anthracite, with a corresponding saving in cost. The +Government's fuel bill now aggregates about $10,000,000 yearly. + + [Illustration: PLATE XXII. + + Fig. 1.--Dryer for Lignite Briquetting Press. + + Fig. 2.--Lignite Briquetting Machine.] + +The making and assembling of chemical analyses and calorific +determinations (checked by other tests) of carefully selected samples of +coals from nearly 1,000 different localities, in the different coal +fields of the United States, with the additions, from time to time, of +samples representing parts of coal fields or newly opened beds of coal +in the same field, furnish invaluable sources of accurate information, +not only for use of the Government, but also for the general public. Of +the above-mentioned localities, 501 were in the public-land States and +427 in the Central, Eastern, and Southern States. + +The chemical analyses of the coals found throughout the United States +have been made with such uniformity of method, both as to collection +of samples and analytical procedure, as to yield results strictly +comparable for coals from all parts of the country, and furnish complete +information, as a basis for future purchases and use by the Government +and by the general public, of all types of American coals. + +Other researches have resulted in the acquirement of valuable +information regarding the distribution of temperature in the fuel bed of +gas producers and furnaces, showing a range of from 400 to 1,300 +cent., and have thus furnished data indicating specific difficulties to +be overcome in gas-producer improvements for greater fuel efficiency. + +The recent studies of the volatile matter in coal, and its relation to +the operation of coke ovens and other forms of combustion, have +demonstrated that as much as one-third of this matter is inert and +non-combustible, a fact which may have a direct bearing on smoke +prevention by explaining its cause and indicating means for its +abatement. + +Experiments in the storage of coal have proven that oxygen is absorbed +during exposure to air, thereby causing, in some cases, a deterioration +in heating value, and indicating that, for certain coals, in case they +are to be stored a long time for naval and other purposes, storage under +water is advisable. + +The tests of different coals under steam boilers have shown the +possibility of increasing the general efficiency of hand-fired steam +boilers from 10 to 15% over ordinary results. If this saving could be +made in the great number of hand-fired boilers now being operated in all +parts of the United States, it would result in large saving in the fuel +bill of the country. Experiments which have been made with +residence-heating boilers justify the belief that it will be possible to +perfect such types of boilers as may economically give a smokeless +operation. The tests under steam boilers furnish specific information as +to the most efficient method of utilizing each of a number of different +types of coal in Government buildings and power plants in different +parts of the country. + +The tests in the gas producer have shown that many fuels of such low +grade as to be practically valueless for steam-furnace purposes, +including slack coal, bone coal, and lignite, may be economically +converted into producer gas, and may thus generate sufficient power to +render them of high commercial value. + +Practically every shipment out of several hundred tested in the gas +producers, including coals as high in ash content as 45%, and lignites +and peats high in moisture, has been successfully converted into +producer gas which has been used in operating gas engines. It has been +estimated that on an average there was developed from each coal tested +in the gas-producer plant two and one-half times the power developed +when used in the ordinary steam-boiler plant, and that such relative +efficiencies will probably hold good for the average plant of moderate +power capacity, though this ratio may be greatly reduced in large steam +plants of the most modern type. It was found that the low-grade lignites +of North Dakota developed as much power, when converted into producer +gas, as did the best West Virginia bituminous coals when utilized under +the steam boiler; and, in this way, lignite beds underlying from +20,000,000 to 30,000,000 acres of public lands, supposed to have little +or no commercial value, are shown to have a large value for power +development. + +The tests made with reference to the manufacture and combustion of +briquetted coal have demonstrated conclusively that by this means many +low-grade bituminous coals and lignites may have their commercial value +increased to an extent which more than covers the increased cost of +making; and these tests have also shown that bituminous coals of the +higher grades may be burned in locomotives with greatly increased +efficiency and capacity and with less smoke than the same coal not +briquetted. These tests have shown that, with the same fuel consumption +of briquettes as of raw coal, the same locomotive can very materially +increase its hauling capacity and thus reduce the cost of +transportation. + +The investigations into smoke abatement have indicated clearly that each +type of coal may be burned practically without smoke in some type of +furnace or with some arrangement of mechanical stoker, draft, etc. The +elimination of smoke means more complete combustion of the fuel, and +consequently less waste and higher efficiency. + +The investigations into the waste of coal in mining have shown the +enormous extent of this waste, aggregating probably from 300,000,000 to +400,000,000 tons yearly, of which at least one-half might be saved. It +is being demonstrated that the low-grade coals, high in sulphur and ash, +now left underground, can be used economically in the gas producer for +power and light, and, therefore, should be mined at the same time that +the high-grade coal is being removed. Moreover, attention is now being +called to the practicability of a further large reduction of waste +through more efficient mining methods. + +The washing tests have demonstrated the fact that many coals, too high +in ash and sulphur for economic use under the steam boiler or for +coking, may be rendered of commercial value by proper treatment in the +washery. The coking tests have also demonstrated that, by proper methods +of preparation for and manipulation in the beehive oven, many coals +which were not supposed to be of economic value for coking purposes, may +be rendered so by prior washing and proper treatment. Of more than 100 +coals tested during 1906 from the Mississippi Valley and the Eastern +States, most of which coals were regarded as non-coking, all except 6 +were found, by careful manipulation, to make fairly good coke for +foundry and other metallurgical purposes. Of 52 coals from the Rocky +Mountain region, all but 3 produced good coke under proper treatment, +though a number of these had been considered non-coking coals. + +Investigations into the relative efficiency of gasoline and denatured +alcohol as power producers, undertaken in connection with work for the +Navy Department, have demonstrated that with proper manipulation of the +carburetters, igniters, degree of compression, etc., denatured alcohol +has the same power-producing value, gallon for gallon, as gasoline. This +is a most interesting development, in view of the fact that the heat +value of a gallon of alcohol is only a little more than 0.6 that of a +gallon of gasoline. To secure these results, compressions of from 150 to +180 lb. per sq. in. were used, these pressures involving an increase in +weight of engine. Although the engine especially designed for alcohol +will be heavier than a gasoline engine of the same size, it will have a +sufficiently greater power capacity so that the weight per horse-power +need not be greater. + +Several hundred tons of peat have been tested to determine methods of +drying, compressing into briquettes, and utilization for power +production in the gas producer. In connection with these peat +investigations, a reconnoissance survey has been made of the peat +deposits of the Atlantic Coast. Samples have been obtained by boring to +different depths in many widely distributed peat-bogs, and these samples +have been analyzed and tested in order to determine their origin, +nature, and fuel value. + +The extent and number of tests from which these results have been +derived will be appreciated from the fact that, in three years, nearly +15,000 tests were made, in each of which large quantities of fuel were +consumed. These tests involved nearly 1,250,000 physical observations +and 67,080 chemical determinations, made with a view to analyze the +results of the tests and to indicate any necessary changes in the +methods as they progressed. For coking, cupola, and washing, 596 tests, +of which nearly 300 involved the use of nearly 1,000 tons of coal, have +been made at Denver. For briquetting, 312 tests have been made. +Briquettes have been used in combustion tests in which 250 tons of +briquetted coal were consumed in battleship tests, 210 tons in +torpedo-boat tests, 320 tons in locomotive tests on three railway +systems, and 70 tons were consumed under stationary steam boilers. Of +producer gas tests, 175 have been made, of which 7 were long-time runs +of a week or more in duration, consuming in all 105 tons of coal. There +have been 300 house-heating boiler tests and 575 steam-boiler tests; +also, 83 railway-locomotive and 23 naval-vessel tests have been made on +run-of-mine coal in comparison with briquetted coal; also, 125 tests +have been made in connection with heat-transmission experiments, and +2,254 gasoline- and alcohol-engine tests. Nearly 10,000 samples of coal +were taken for analysis, of which 3,000 were from public-land States. +Nearly 5,000 inspection samples, of coal purchased by the Government for +its use, have been taken and tested. + +The results of the tests made in the course of these investigations, as +summarized, have been published in twelve separate Bulletins, three of +which, Nos. 261, 290, and 332, set forth in detail the operations of the +fuel-testing plant for 1904, 1905, and 1906. Professional Paper No. 48, +in three volumes, describes in greater detail each stage of the +operations for 1904 and 1905. + +Separate Bulletins, descriptive of the methods and results of the work +in detail, have been published, as follows: No. 323, Experimental work +conducted in the chemical laboratory; No. 325, A study of four hundred +steaming tests; No. 334, Burning of coal without smoke in boiler plants; +No. 336, Washing and coking tests of coal, and cupola tests of coke; No. +339, Purchase of coal under specifications on basis of heating value; +No. 343, Binders for coal briquettes; No. 362, Mine sampling and +chemical analyses of coals in 1907; No. 363, Comparative tests of +run-of-mine and briquetted coal on locomotives, including torpedo-boat +tests, and some foreign specifications for briquetted fuel; No. 366, +Tests of coal and briquettes as fuel for house-heating boilers; No. 367, +Significance of drafts in steam-boiler practice; No. 368, Coking and +washing tests of coal at Denver; No. 373, Smokeless combustion of coal +in boiler plants, with a chapter on central heating plants; No. 378, +Results of purchasing coal under Government specifications; No. 382, +The effect of oxygen in coal; and, No. 385, Briquetting tests at +Norfolk, Va. + + + + +DISCUSSION + + +KENNETH ALLEN, M. Am. Soc. C. E.--The speaker would like to know whether +anything has been done in the United States toward utilizing marsh mud +for fuel. + +In an address by Mr. Edward Atkinson, before the New England Water Works +Association, in 1904, on the subject of "Bog Fuel," he referred to its +extensive use in Sweden and elsewhere, and intimated that there was a +wide field for its use in America. + +The percentage of combustible material in the mud of ordinary marsh +lands is very considerable, and there are enormous deposits readily +available; but it is hardly probable that its calorific value is +sufficiently high to render its general use at this time profitable. + +As an example of the amount of organic matter which may remain stored in +these muds for many years, the speaker would mention a sample taken from +the bottom of a trench, which he had analyzed a few years ago. Although +taken from a depth of about 15 ft., much of the vegetable fiber remained +intact. The material proved to be 70% volatile. + +Possibly before the existing available coal deposits are exhausted, the +exploitation of meadow muds for fuel may become profitable. + + +HENRY KREISINGER, Esq.[29] (by letter).--Mr. Wilson gives a brief +description of a long furnace and an outline of the research work which +is being done in it. It may be well to discuss somewhat more fully the +proposed investigations and point out the practical value of the +findings to which they may lead. + +In general, the object is to study the process of combustion of coal. +When soft coal is burned in any furnace, part of the combustible is +driven off shortly after charging, and has to be burned in the space +between the fuel bed and the exit of the gases, which is called the +combustion space. There is enough evidence to show that, with a constant +air supply, the completeness of the combustion of the volatile +combustible depends on the length of time the latter stays within the +combustion space; but, with a constant rate of charging the coal, this +length of time depends directly on the extent of the combustion space. +Thus, if the volume of the volatile combustible evolved per second and +the admixed air is 40 cu. ft., and the extent of the combustion space is +80 cu. ft., the average time the gas will stay within the latter is 2 +sec.; if the combustion space is 20 cu. ft., the average time the +mixture can stay in this space is only sec., and its combustion will +be less complete than in the first case. Thus it is seen that the extent +of the combustion space of a furnace is an important factor in the +economic combustion of volatile coals. The specific object of the +investigations, thus far planned, is to determine the extent of the +combustion space required to attain practically complete combustion when +a given quantity of a given coal is burned under definite conditions. +With this object in view, the furnace has been provided with a +combustion space large enough for the highest volatile coals and for the +highest customary rate of combustion. To illustrate the application of +the data which will be obtained by these experiments, the following +queries are given: + +Suppose it is required to design a furnace which will burn coal from a +certain Illinois mine at the rate of 1,000 lb. per hour, with a +resulting temperature of not less than 2,800 Fahr. How large a +combustion space is required to burn, with practical completeness, the +volatile combustible? What completeness of combustion can be attained, +if the combustion space is only three-fourths of the required extent? In +the present state of the knowledge of the process of combustion of coal, +these queries cannot be answered definitely. In the literature on +combustion one may find statements that the gases must be completely +burned before leaving the furnace or before they strike the cooling +surfaces of the boiler; but there is no definite information available +as to how long the gases must be kept in the furnace or how large the +combustion space must be in order to obtain practically complete +combustion. It is strange that so little is known of such an old art as +the combustion of coal. + +The research work under consideration is fundamentally a problem in +physical chemistry, and, for that reason, has been assigned to a +committee consisting of the writer as Engineer, Dr. J. C. W. Frazer, +Chemist, and Dr. J. K. Clement, Physicist. The outcome of the +investigation may prove of extreme interest to mechanical and fuel +engineers, and to all who have anything to do with the burning of coal +or the construction of furnaces. In the experiments thus far planned the +following factors will be considered: + +_Effect of the Nature of Coal on the Extent of Combustion Space +Required._--The steaming coals mined in different localities evolve +different volumes of volatile combustible, even when burned at the same +rate. The coal which analyzes 45% of volatile matter evolves a much +greater volume of gases and tar vapors than that analyzing only 15 per +cent. These evolved gases and tar vapors must be burned in the space. +Consequently, a furnace burning high volatile coal must have a much +larger combustion space than that burning coal low in volatile +combustible. + +There is enough evidence to show that the extent of combustion space +required to burn the volatile combustible depends, not only on the +volume of the combustible mixture, but also on the chemical composition +of the volatile combustible. Thus the volatile combustible of low +volatile coal, when mixed with an equal volume of air, may require 1 +sec. in the combustion space to burn practically to completeness, while +it may require 2 sec. to burn the same volume of the volatile +combustible of high volatile coal with the same completeness; so that +the extent of the combustion space required to burn various kinds of +coal may not be directly proportional to the volatile matter of the +coal. + +_Effect of the Rate of Combustion on the Extent of Combustion Space +Required._--With the same coal, the volume of the volatile combustible +distilled from the fuel bed per unit of time varies as the rate of +combustion. Thus, when this rate is double that of the standard, the +volume of gases and tar vapors driven from the fuel is about doubled. To +this increased volume of volatile combustible, about double the volume +of air must be added, and, if the mixture is to be kept the same length +of time within the combustion space, the latter should be about twice as +large as for the standard rate of combustion. Thus the combustion space +required for complete combustion varies, not only with the nature of the +coal, but also with the rate of firing the fuel, which, of course, is +self-evident. + +_Effect of Air Supply on the Extent of Combustion Space +Required._--Another factor which influences the extent of the combustion +space is the quantity of air mixed with the volatile combustible. +Perhaps, within certain limits, the combustion space may be decreased +when the supply of air is increased. However, any statement at present +is only speculation; the facts must be determined experimentally. One +fact is known, namely, that, in order to obtain higher temperatures of +the products of combustion, the air supply must be decreased. + +_Effect of Rate of Heating of Coal on the Extent of Combustion Space +Required._--There is still another factor, a very important one, which, +with a given coal and any given air supply, will influence the extent of +the combustion space. This factor is the rate of heating of the coal +when feeding it into the furnace. The so-called "proximate" analysis of +coal is indeed only very approximate. When the analysis shows, say, 40% +of volatile matter and 45% of fixed carbon, it does not mean that the +coal is actually composed of so much volatile matter and so much fixed +carbon; it simply means that, under a certain rate of heating attained +by certain standard laboratory conditions, 40% of the coal has been +driven off as "volatile matter." If the rate or method of heating were +different, the amount of volatile matter driven off would also be +different. Chemists state that it is difficult to obtain accurate checks +on "proximate" analysis. To illustrate this factor, further reference +may be made to the operation of the up-draft bituminous gas producers. +In the generator of such producers the tar vapors leave the freshly +fired fuel, pass through the wet scrubber, and are finally separated by +the tar extractor as a black, pasty substance in a semi-liquid state. If +this tar is subjected to the standard proximate analysis, it will be +shown that from 40 to 50% of it is fixed carbon, although it left the +gas generator as volatile matter. It is desired to emphasize the fact +that different rates of heating of high volatile coals will not only +drive off different percentages of volatile matter, but that the latter +itself varies greatly in chemical composition and physical properties as +regards inflammability and rapidity of combustion. Thus it may be said +that the extent of the combustion space required for the complete +oxidation of the volatile combustible depends on the method of charging +the fuel, that is, on how rapidly the fresh fuel is heated. If this +factor is given proper consideration, it may be possible to reduce very +materially the necessary space required for complete combustion. + +_The Effect of the Rate of Mixing the Volatile Combustible and Air on +the Extent of the Combustion Space._--When studying the effects +discussed in the preceding paragraphs, the rate of mixing the volatile +combustible with the supply of air must be as constant as practicable. +At first, tests will be made with no special mixing devices, the mixing +will be accomplished entirely by the streams of air entering the furnace +at the stoker, and by natural diffusion. Although there appears to be +violent stirring of the gases above the fuel bed, the mixture of the +gases does not become homogeneous until they are about 10 or 15 ft. from +the stoker. The mixing caused by the air currents forced into the +furnace at the stoker is very distinct, and can be readily observed +through the peep-hole in the side wall of the Heine boiler, opposite the +long combustion chamber. This mixing is shown in Fig. 20. _A_ is a +current of air forced from the ash-pit directly upward through the fuel +bed; _B_ and _B_ are streams of air forced above the fuel bed through +numerous small openings at the furnace side of each hopper. Those +currents cause the gases to flow out of the furnace in two spirals, as +shown in Fig. 20. The velocity of rotation on the outside of the two +spirals appears to be about 10 ft. per sec., when the rate of combustion +is about 750 lb. of coal per hour. It is reasonable to expect that when +the rate of mixing is increased by building piers and other mixing +structures immediately back of the grate, the completeness of the +combustion will be effected in less time, and a smaller combustion space +will be required. Thus, the mixing structures may be an important factor +in the extent of the required combustion space. + +To sum up, it can be said that the extent of the space required to +obtain a combustion which can be considered complete for all practical +purposes, depends on the following factors: + + (_a_).--Nature of coal, + + (_b_).--Rate of combustion, + + (_c_).--Supply of air, + + (_d_).--Rate of heating fuel, + + (_e_).--Rate of mixing volatile combustible and air. + +Just how much the extent of the combustion space required will be +influenced by these factors is the object of the experiments under +discussion. + +_The Scope of the Experiments._--With this object in view, as explained +in the preceding paragraphs, the following series of experiments are +planned: + + [Illustration: Fig. 20. + + SECTION THROUGH STOKER SHOWING MIXING OF GASES + CAUSED BY CURRENTS OF AIR] + +Six or eight typical coals are to be selected, each representing a +certain group of nearly the same chemical composition. Each series will +consist of several sets of tests, each set being run with all the +conditions constant except the one, the effect of which on the size of +the combustion space is to be investigated. Thus a set of four or five +tests will be made, varying in rate of combustion from 20 to 80 lb. of +coal per square foot of grate per hour, keeping the supply of air per +pound of combustible and the rate of heating constant. This set will +show the effect of the rate of combustion of the coal on the extent of +space required to obtain combustion which is practically complete. Other +variables, such as composition of coal, supply of air, and rate of +heating, remain constant. + +Another set of four or five tests will be made with the same coal and at +the same rate of combustion, but the air supply will be different for +each test. This set of tests will be repeated for two or three different +rates of combustion. Thus each of these sets will give the effect of the +air supply on the extent of combustion space when the coal and rate of +combustion remain constant. + +Still another set of tests should be made in which the time of heating +the coal when feeding it into the furnace will vary from 3 to 30 min. In +each of the tests of this set, the rate of combustion and the air supply +will be kept constant, and the set will be repeated for two or three +rates of combustion and two or three supplies of air. Each of these sets +of tests will give the effect of the rate of heating of fresh fuel on +the extent of combustion space required to burn the distilled volatile +combustible. These sets of experiments will require a modification in +the stoker mechanism, and, on that account, may be put off until all the +other tests on the other selected typical coals are completed. As the +investigation proceeds, enough may be learned so that the number of +tests in each series may be gradually reduced. After all the desirable +tests are made with the furnace as it stands, several kinds of mixing +structures will be built successively back of the stoker and tried, one +kind at a time, with a set of representative tests. Thus the +effectiveness of such mixing structures will be determined. + +_Determining the Completeness of Combustion._--The completeness of +combustion in the successive cross-sections of the stream of gases is +determined mainly by the chemical analysis of samples of gases collected +through the openings at these respective cross-sections. The first of +these cross-sections at which gas samples are collected, passes through +the middle of the bridge wall; the others are placed at intervals of 5 +ft. through the entire length of the furnace. Measurements of the +temperature of the gases, and direct observations of the length and +color of the flames and of any visible smoke will be also made through +the side peep-holes. These direct observations, together with the gas +analysis, will furnish enough data to determine the length of travel of +the combustible mixture to reach practically complete combustion. + +In other words, these observations will determine the extent of the +combustion space for various kinds of coal when burned under certain +given conditions. Direct observations and the analysis of gases at +sections nearer the stoker than that at which the combustion is +practically complete, will show how the process of combustion approaches +its completion. This information will be of extreme value in determining +the effect of shortening the combustion space on the loss of heat due to +incomplete combustion. + +_Method of Collecting Gas Samples._--The collection of gas samples is a +difficult problem in itself, when one considers that the temperature of +the gases, as they are in the furnace, ranges from 2,400 to 3,200 +Fahr.; consequently, the samples must be collected with water-cooled +tubes. Thus far, about 25 preliminary tests have been made. These tests +show that the composition of the gases at the cross-sections near the +stoker is not uniform, and that more than one sample must be taken from +each cross-section. It was decided to take 9 samples from the +cross-section immediately back of the stoker, and reduce the number in +the sections following, according to the uniformity of the gas +composition. Thus, about 35 simultaneous gas samples must be taken for +each test. The samples will be subjected, not only to the usual +determination of CO_{2}, O_{2} and CO, but to a complete analysis. It is +also realized that some of the carbon-hydrogen compounds which, at the +furnace temperature, exist as heavy gases, are condensed to liquids and +solids when cooled in the sampling tubes, where they settle and tend to +clog it. To neglect the presence of this form of the combustible would +introduce considerable error in the determination of the completeness of +combustion at any of the cross-sections. Therefore, special water-cooled +sampling tubes are constructed and equipped with filters which separate +the liquid and solid combustible from the gases. The contents of these +filters are then also subjected to complete analysis. To obtain +quantitative data, a measured quantity of gases must be drawn through +these filtering sampling tubes. + +_The Measuring of Temperatures._--At present the only possible known +method of measuring the temperature of the furnace gases is by optical +and radiation pyrometers. Platinum thermo-couples are soon destroyed by +the corrosive action of the hot gases. The pyrometers used at present +are the Wanner optical pyrometer and the Fery radiation pyrometer. + +_The Flow of Heat Through Furnace Walls._--An interesting side +investigation has developed, in the study of the loss of heat through +the furnace walls. In the description of this experimental furnace it +has been said that the side walls contained a 2-in. air space, which, in +the roof, was replaced with a 1-in. layer of asbestos. To determine the +relative resistance to heat flow of the air space and the asbestos +layer, 20 thermo-couples were embedded, in groups of four, to different +depths at three places in the side wall and at two places in the roof. +In the side wall, one of the thermo-couples of each group was placed in +the inner wall near the furnace surface; the second thermo-couple was +placed in the same wall, but near the surface facing the air space; the +third thermo-couple was placed in the outer wall near the inner surface; +and the fourth was placed near the outer surface in the outer wall. In +the roof the second and third thermo-couples were placed in the brick +near the surface on each side of the asbestos layer. These +thermo-couples have shown that the temperature drop across the 2-in. air +space was much less than that across the 1-in. layer of asbestos; in +fact, that it was considerably less than the temperature drop through +the same thickness of the brick wall. + +The results obtained prove that, as far as heat insulation is concerned, +air spaces in furnace walls are undesirable. The heat is not conducted +through the air, but leaps across the space by radiation. In furnace +construction a solid wall is a better heat insulator than one of the +same total thickness containing an air space. If it is necessary to +build a furnace wall in two parts on account of unequal expansion, the +space between the two walls should be filled with some solid, cheap, +non-conducting materials, such as ash, sand, or crushed brick. A more +detailed account of these experiments may be found in a Bulletin of the +U.S. Geological Survey entitled "The Flow of Heat Through Furnace +Walls." + + +WALTER O. SNELLING, Esq.[30] (by letter).--The work of the United States +Testing Station at Pittsburg has been set forth so fully by Mr. Wilson +that a further statement as to the results achieved may seem like +repetition. It would be most unlikely, however, that studies of such +variety should possess no other value than along the direct lines being +investigated. In the case of the Mine Accidents Division, at least, it +is certain that the indirect benefits of some of the studies have been +far-reaching, and are now proving of value in lines far removed from +those which were the primary object of the investigation. They are +developing facts which will be of great value to all engineers or +contractors engaged in tunneling or quarrying. As the writer's +experience has been solely in connection with the chemical examination +of explosives, he will confine his discussion to this phase. + +In studying the properties of various explosives, and in testing work to +separate those in which the danger of igniting explosive mixtures of +coal dust and air, or of fire-damp and air, is greatest, from those in +which this danger is least, much information has been collected. Mr. +Wilson has described many of the tests, and it can be readily seen that +in carrying out these and other tests on each of the explosives +submitted, a great many facts relating to the properties of explosive +compounds have been obtained, which were soon found to be of decided +value in directions other than the simple differentiation of explosives +which are safe from those which are unsafe in the presence of explosive +mixtures of fire-damp or coal dust. + +The factors which determine the suitability of an explosive for work in +material of any particular physical characteristics depend on the +relationship of such properties as percussive force (or the initial blow +produced by the products of the decomposition of the explosive at the +moment of explosion), and the heaving force (or the continued pressure +produced by the products of the decomposition, after the initial blow at +the instant of detonation). Where an explosive has been used in coal or +rock of a certain degree of brittleness, and where the work of the +explosive with that particular coal is not thoroughly satisfactory, it +becomes evident that through the systematic use of the information +available at the Testing Station (and now in course of publication in +the form of bulletins), in regard to the relationship between percussive +and heaving forces in different explosives, as shown by the tests with +small lead blocks, the Trauzl test, and the ballistic pendulum, that +explosives can be selected which, possessing in modified form the +properties of the explosive not entirely satisfactory in that type of +coal or rock, would combine all the favorable properties of the first +explosive, together with such additional advantages as would come from +its added adaptation to the material in which it is to be used. + +For example, if the explosive in use were found to have too great a +shattering effect on the coal, an examination of the small lead-block +test of this explosive, and a comparison of this with lead-block tests +of other explosives having practically the same strength, as shown by +the ballistic pendulum, will enable the mine manager to select from +those already on the Permissible List (and therefore vouched for in +regard to safety in the presence of gas and coal dust, when used in a +proper way), some explosive which will have the same strength, and yet +which, because of lessened percussive force or shattering effect, will +produce coal in the manner desired. If one takes the other extreme, and +considers a mine in which the product is used exclusively for the +preparation of coke (and therefore where shattering of the coal is in no +way a disadvantage), the mine superintendent's interest will be +primarily to select an explosive which, as indicated by suitable +lead-block, Trauzl, and ballistic pendulum tests, will produce the +greatest amount of coal at the least cost. + +As the cost of the explosive does not form any part of the tables +prepared by the Testing Station, the relative cost must be computed from +the manufacturer's prices, but the results tabulated by the Station will +contain all the other data necessary to give the mine superintendent +(who cares to take the small amount of trouble necessary to familiarize +himself with the tables) all the information which is required to +compare the action of one explosive with that of any other explosive +tested. + +In this way it is seen that, aside from the primary consideration of +safety in the presence of explosive mixtures of fire-damp and coal dust +(a condition alike fulfilled by all explosives admitted to the +Permissible List), the data prepared by the Testing Station also give +the information necessary to enable the discriminating mine manager to +select an explosive adapted to the particular physical qualities of the +coal at his mine, or to decide intelligently between two explosives of +the same cost on the basis of their actual energy content in the +particular form of the heaving or percussive force required in his work. + +Up to the present time the investigations have been confined to +explosives used in coal mining, because the Act of Congress establishing +the Testing Station has thus limited its work. Accordingly, it is not +possible to compare, on the systematic basis just mentioned, the +explosives generally used in rock work. It is probable that, if the Bill +now before Congress in regard to the establishment of a Bureau of Mines +is passed, work of this character will be undertaken, and the tables of +explosives now prepared will be extended to cover all those intended for +general mining and quarrying use. Data of such character are +unobtainable to-day, and, as a result, a considerable percentage of +explosives now used in all mining operations is wasted, because of their +lack of adaptation to the materials being blasted. It is well known, for +example, that when an explosive of high percussive force is used in +excavating in a soft or easily compressed medium, a considerable +percentage of its force is wasted as heat energy, performing no other +function than the distortion and compression of the material in which it +is fired, without exerting either an appreciable cracking or fissuring +effect, or a heaving or throwing of the material. + +Owing to lack of information in regard to the exact relationship between +the percussive and the heaving force in particular explosives, this +waste, as compared with the quantity required for the work with a +properly balanced material, will continue; but it is to be hoped that it +will soon be possible to give the mining and quarrying industries +suitable information in regard to the properties of the various +explosives, so that the railroad contractor and the metal miner may have +the same simple and exact means of discrimination between suitable and +unsuitable explosives that is now being provided for the benefit of the +coal miner. + +Another of the important but indirect benefits of this work has been the +production of uniformity of strength and composition in explosives. An +example of this helpful influence is the standardization of detonating +caps and electric detonators. In the early days of the explosive +industry, it was apparently advantageous for each manufacturer to have a +separate system of trade nomenclature by which to designate the +strengths of the different detonators manufactured by him. The necessity +and even the advantage of such methods have long been outgrown, and yet, +until the past year, the explosive industry has had to labor under +conditions which made it almost impossible for the user of explosives to +compare, in cost or strength, detonators of different manufacturers; or +to select intelligently the detonator best suited to the explosive to be +used. After conference with the manufacturers of detonating caps and +electric detonators, a standard system of naming the strengths of these +products has been selected by the Testing Station, and has met with a +most hearty response. It is encouraging to note that, in recent trade +catalogues, detonators are named in such a way as to enable the user to +determine directly the strength of the contained charge, which is a +decided advantage to every user of explosives and also to manufacturers. + +The uniformity of composition of explosives (and many difficulties in +mining work and many accidents have been rightly or wrongly attributed +to lack of uniformity) may be considered as settled in regard to all +those on the Permissible List. One of the conditions required of every +explosive on that list is that its composition must continue +substantially the same as the samples submitted originally for official +test. Up to the present, all explosives admitted to the Permissible List +have maintained their original composition, as determined by subsequent +analyses of samples selected from mines in which the explosive was in +use, and comparison with the original samples. + +The data assembled by the Testing Station in regard to particular +explosives have also been of great benefit to the manufacturers. When +the explosives tests were commenced, comparatively few explosives were +being made in the United States for which it was even claimed by the +manufacturers that they were at all safe in the presence of explosive +mixtures of gas or coal dust. It was evident that, without systematic +tests, very little knowledge of the safety or lack of safety of any +particular explosive could ever be gained, and, consequently, the user +of explosives was apt to regard with incredulity any claim by the +manufacturer in regard to the qualities of safety. Owing to lack of +proof, this was most natural; and it was also evident that the very slow +process of testing, which was offered by a study of mine explosions +during past years, was sufficient only to prove the danger of black +powder, and not in any way to indicate the safety of any of the brands +of mining powder for which this property was claimed. Indeed, one of the +few explosives to which the name, "safety," was attached, at the time +the Government experiments were first undertaken, was found to be +anything but safe when tested in the gallery, although there is no +reason to believe that the makers of this and other explosives claiming +"safety" for their product, did not have the fullest confidence in their +safety. + +The Testing Station offered the first opportunity in the United States +to obtain facts in regard to the danger of any particular explosive in +the presence of explosive mixtures of gas or coal dust. With most +commendable energy, the manufacturers of explosives, noting the early +failures of their powders in the testing gallery, began at once to +modify them in such ways as suggested by the behavior of the explosives +when under test, and, in a short time, returned to the Testing Station +with improved products, able to stand the severe tests required. In this +way the Testing Station has been a most active agent in increasing the +general safety of explosives, and the manufacturers have shown clearly +that it never was their desire to offer inferior explosives to the +public, but that their failures in the past were due solely to lack of +information in regard to the action of explosives under the conditions +which exist before a mine disaster. The chance being offered to +duplicate, at the Testing Station, the conditions represented in a mine +in the presence of gas, they showed an eagerness to modify and improve +their explosives so as to enable them to answer severe mining +conditions, which is most commendable to American industry. + +In regard to the unfavorable conditions existing in mines in the past, +the same arguments may be used. In spite of the frequency of mine +accidents in the United States, and in spite of the high death rate in +coal mining as compared with that in other countries, it must be said in +fairness that this has been the result of ignorance of the actual +conditions which produce mine explosions, rather than any willful +disregard of the known laws of safety by mine owners. Conditions in +American mines are far different from those obtaining in mines abroad, +and, as a result, the rules which years of experience had taught to +foreign colliery managers were not quickly applied to conditions +existing in American mines; but, as soon as the work at the Pittsburg +Station had demonstrated the explosibility of the coal dust from +adjoining mines, and had shown the very great safety of some explosives +as compared with others, there was at once a readiness on the part of +mine owners throughout the country to improve conditions in their mines, +and to take advantage of all the studies made by the Government, thus +showing clearly that the disasters of the past had been due to lack of +sufficient information rather that to any willful disregard of the value +of human lives. + +Another of the indirect benefits of the work of the Station has resulted +from its examination of explosives for the Panama Canal. For several +years the Isthmian Canal Commission has been one of the largest users of +explosives in the world, and, in the purchase of the enormous quantities +required, it was found necessary to establish a system of careful +examination and inspection. This was done in order to insure the safety +of the explosives delivered on the Isthmus, and also to make certain +that the standards named in the contract were being maintained at all +times. With its established corps of chemists and engineers, it was +natural that this important work should be taken up by the Technologic +Branch of the United States Geological Survey, and, during the past +three years, many millions of pounds of dynamite have been inspected and +samples analyzed by the chemists connected with the Pittsburg Testing +Station, thus insuring the high standard of these materials. + +One of the many ways in which this work for the Canal Commission has +proved of advantage is shown by the fact that, as a result of studies at +the Testing Station, electric detonators are being made to-day which, in +water-proof qualities, are greatly superior to any similar product. As +the improvements of these detonators were made by a member of the +testing staff, all the pecuniary advantages arising from them have gone +directly to the Government, which to-day is obtaining superior electric +detonators, and at a cost of about one-third of the price of the former +materials. + +All the work of the Technologic Branch is being carried out along +eminently practical lines, and is far removed from such work as can be +taken up advantageously by private or by State agencies. The work of the +Mine Accidents Division was taken up primarily to reduce the number of +mine accidents, and to increase the general conditions of safety in +mining. As the work of this Division has progressed, it has been found +to be of great advantage to the miner and the mine owner, while the +ultimate results of the studies will be of still greater value to every +consumer of coal, as they will insure a continued supply of this +valuable product, and at a lower cost than if the present methods, +wasteful alike in lives and in coal, had been allowed to continue for +another decade. + + +A. BARTOCCINI, Assoc. M. Am. Soc. C. E. (by letter).--The writer made a +personal investigation of the mine disaster of Cherry, Ill. He +interviewed the men who escaped on the day of the accident, and also +several of those who were rescued one week later. He also interrogated +the superintendent and the engineer of the mine, and obtained all the +information asked for and also the plans of the mine showing the +progress of the work. + +After a careful investigation the writer found that the following +conditions existed at the mine at the time of the disaster: + + _First._--There were no means for extinguishing fires in the mine. + + _Second._--There were no signal systems of any kind. Had the mine been + provided with electric signals and telephones, like some of the most + modern mines in the United States, the majority of the men could have + been saved, by getting into communication with the outside and working + in conjunction with the rescuers. + + _Third._--The miners had never received instructions of how to behave + in case of fire. + + _Fourth._--The main entries and stables were lighted with open + torches. + + _Fifth._--The organization of the mine was defective in some way, for + at the time of the disaster orders came from every direction. + + _Sixth._--The air shaft was used also as a hoisting shaft. + + _Seventh._--The main shaft practically reached only to the second + vein; its extension to the third and deepest vein was not used. + + _Eighth._--Plans of the workings of the second and third veins were + not up to date. The last survey recorded on them was that of June, + 1909. This would have made rescue work almost impossible to men not + familiar with the mine. + + _Ninth._--The inside survey of the mine was not connected with the + outside survey. + +Would it not be possible for the United States Geological Survey to +enforce rules which would prevent the existence of conditions such as +those mentioned? The Survey is doing wonderful work, as shown by the +rescue of twenty miners at Cherry one week after the conflagration; but +there is no doubt that perhaps all the men could have been saved if +telephone communications with the outside had been established. +Telephone lines to resist any kind of a fire, can easily be installed, +and the expense is small, almost negligible when one considers the +enormous losses suffered by the mine owners and by the families of the +victims. + + +H. G. STOTT, M. Am. Soc. C. E.--The curves shown by Mr. Wilson give a +clear general idea of the relative efficiencies of steam and gas engines +when treated from a purely theoretical thermodynamic point of view. This +point of view, however, is only justified when small units having a +maximum brake horse-power not exceeding 1,000 are considered. + +The steam engine or turbine operating under a gauge pressure of 200 lb. +per sq. in., and with 150 superheat, has a maximum temperature of 538 +Fahr. in its cylinder, while that of the gas engine varies between +2,000 and 3,000 Fahr. + +The lubrication of a surface continually subjected to the latter +temperature would be impossible, so that water jackets on the cylinders +and, in the larger units, in the pistons become absolutely necessary. As +the cylinders increase in diameter, it is necessary, of course, to +increase their strength in proportion to their area, which, in turn, is +proportional to the square of the diameter. The cooling surface, +however, is only proportional to the circumference, or a single function +of the diameter. Increasing the strength in proportion to the square of +the diameter soon leads to difficulties, because of the fact that the +flow of heat through a metal is a comparatively slow process; the thick +walls of the cylinders on large engines cannot conduct the heat away +fast enough, and all sorts of strains are set up in the metal, due to +the enormous difference in temperature between the inside and the jacket +lining of the cylinder. + +These conditions produce cut and cracked cylinders, with a natural +resultant of high maintenance and depreciation costs. These costs, in +some cases, have been so great, not only in the United States, but in +Europe and Africa, as to cause the complete abandonment of large gas +engine plants after a few years of attempted operation. + +The first consideration in any power plant is that it shall be +thoroughly reliable in operation, and the second is that it shall be +economical, not only in operation, but in maintenance and depreciation. +Therefore, in using the comparative efficiency curves shown in Mr. +Wilson's paper it should be kept in mind that the cost of power is not +only the fuel cost, but the fuel plus the maintenance and depreciation +charges, and that the latter items should not be taken from the first +year's account, but as an average of at least five years. + +The small gas engine is a very satisfactory apparatus when supplied with +good, clean gas, and when given proper attention, but great caution +should be used before investing in large units, until further +developments in the art take place, as conservation of capital is just +as important as conservation of coal. + + +B. W. DUNN, Esq.[31] (by letter.)--The growing importance of +investigations of explosives, with a view to increasing the consumer's +knowledge of proper methods for handling and using them, is evident when +it is noted that the total production of explosives in the United States +has grown from less than 9,000,000 lb. in 1840 to about 215,000,000 lb. +in 1905. Table 5 has been compiled by the Bureau of Explosives of the +American Railway Association. + + TABLE 5.--Manufacture of Explosives in the United States, 1909. + + ---------------------+-------------+------------------------------ + Kind of explosives. | Number of | Maximum Capacity, in Pounds. + | factories. +--------------+--------------- + | | Daily. | Annual. + ---------------------+-------------+--------------+--------------- + Black powder | 49 | 1,220,150 | 366,135,000 + High explosives | 37 | 1,203,935 | 361,180,500 + Smokeless powders | 5 | 75,686 | 22,705,800 + ---------------------+-------------+--------------+--------------- + +The first problem presented by this phenomenal increase relates to the +safe transportation of this material from the factories to points of +consumption. A package of explosives may make many journeys through +densely populated centers, and rest temporarily in many widely separated +storehouses before it reaches its final destination. A comprehensive +view of the entire railway mileage of the United States would show at +any instant about 5,000 cars partially or completely loaded with +explosives. More than 1,200 storage magazines are listed by the Bureau +of Explosives as sources of shipments of explosives by rail. + +The increase in the demand for explosives has not been due entirely to +the increase in mining operations. The civil engineer has been expanding +his use of them until now carloads of dynamite, used on the Isthmus of +Panama in a single blast, bring to the steam shovels as much as 75,000 +cu. yd. of material, the dislodgment of which by manual labor would have +required days of time and hundreds of men. Without the assistance of +explosives, the construction of subways and the driving of tunnels would +be impracticable. Even the farmer has awakened to the value of this +concentrated source of power, and he uses it for the cheap and effective +uprooting of large stumps over extended areas in Oregon, while an entire +acre of subsoil in South Carolina, too refractory for the plow, is +broken up and made available for successful cultivation by one explosion +of a series of well-placed charges of dynamite. It has also been found +by experience that a few cents' worth of explosive will be as effective +as a dollar's worth of manual labor in preparing holes for transplanting +trees. + +The use of explosives in war and in preparation for war is now almost a +negligible quantity when compared with the general demand from peaceful +industries. With the completion of the Panama Canal, it is estimated +that the Government will have used in that work alone more explosives +than have been expended in all the battles of history. + +Until a few years ago little interest was manifested by the public in +safeguarding the manufacture, transportation, storage, and use of +explosives. Anyone possessing the necessary degree of ignorance, or +rashness, was free to engage in their manufacture with incomplete +equipment; they were transported by many railroads without any special +precautions; the location of magazines in the immediate vicinity of +dwellings, railways, and public highways, was criticized only after some +disastrous explosion; and the often inexperienced consumer was without +access to a competent and disinterested source of information such as he +now has in the testing plant at Pittsburg so well described by Mr. +Wilson. + +The first general move to improve these conditions is believed to have +been made by the American Railway Association in April, 1905. It +resulted in the organization of a Bureau of Explosives which, through +its inspectors, now exercises supervision over the transportation of all +kinds of dangerous articles on 223,630 of the 245,000 miles of railways +in the United States and Canada. A general idea of the kind and volume +of inspection work is shown by the following extracts from the Annual +Report of the Chief Inspector, dated February, 1910: + + 1909. 1908. + "Total number of railway lines members of + Bureau December 31st 172 158 + Total mileage of Bureau lines December 31st 209,984 202,186 + Total number of inspections of stations for + explosives 6,953 5,603 + Number of stations receiving two or more + inspections for explosives 1,839 1,309 + Total number of inspections of stations + for inflammables 6,950 1,098 + Number of stations receiving two or more + inspections for inflammables 1,886 .... + Total number of inspections of factories 278 270 + Number of factories receiving two or more + inspections 75 69 + Total number of inspections of magazines 1,293 1,540 + Number of magazines receiving two or more + inspections 349 361 + Total number of boxes of high explosives + condemned as unsafe for transportation 10,029 4,852 + Total number of kegs of black powder + condemned as unsafe for transportation 1,468 531 + Total number of cars in transit containing + explosives inspected 475 448 + Total number of cars in transit showing serious + violations of the regulations 168 197 + Total number of inspections of steamship + companies' piers + (inflammable, 75; explosive, 63) 138 .... + Total number of inspections made by Bureau 16,087 8,959 + Total number of lectures to railway officials + and employes and meetings addressed on the + subject of safe transportation of explosives + and other dangerous articles 215 171 + + 1909. 1908. 1907. + "Total number of accidents resulting + in explosions or fires in + transportation of explosives by rail 12 22 79 + Total known property loss account + explosions or accidents in + transporting explosives by rail $2,673 $114,629 $496,820 + Total number of persons injured by + explosions in transit 7 53 80 + Total number of persons killed by + explosions in transit 6 26 52 + + "During the same period reports have been rendered to the Chief + Inspector by the Chemical Laboratory of the Bureau on 734 samples, + as follows: + + Explosives 211 + Fireworks 186 + Inflammables 304 + Paper for lining high explosive boxes 31 + Ammunition 2 + ---- + Total 734 + + "As a means of ensuring the uniform enforcement of the regulations, by + a well grounded appreciation of their significance and application, + the lectures delivered by representatives of the Bureau have proved + most successful. The promulgation of the regulations is not of itself + sufficient to ensure uniformity or efficiency in their observance, and + so these lectures form a valuable supplement to the inspection + service. They have been successfully continued throughout the year, + and the requests for the delivery of them by the managements of so + many of the membership lines, is a convincing testimonial of the high + esteem in which they are held. + + "While the lectures are primarily intended for the instruction and + information of the officials and employes of the railway companies, + and especially of those whose duties bring them into immediate contact + with the dangerous articles handled in transportation, the + manufacturers and shippers are invited, and they have attended them in + considerable numbers. Many of this class have voluntarily expressed + their commendation of the lectures as a medium of education, and + signified their approval of them in flattering terms. + + "The scope of these lectures embraces elementary instruction in the + characteristics of explosives and inflammables and the hazards + encountered in their transportation and in what respects the + regulations afford protection against them. The requirements of the + law, and the attendant penalties for violation, are fully described. + Methods of preparation, packing, marking, receiving, handling and + delivering, are explained by stereopticon lantern slides. These are + interesting of themselves, and are the best means of stamping the + impression they are intended to convey upon the minds of the + audiences, and are always an acceptable feature of the lectures. The + reception generally given to the lectures by those who have attended + them, often at the voluntary surrender of time intended for rest while + off duty, may be stated as an indication that the subject matter is + one in which they are interested. + + "The facilities of the Young Men's Christian Association, in halls, + lanterns and skilled lantern operators, have been generously accorded + and made use of to great advantage, in connection with the lectures at + many places. The co-operation of this Association affords a convenient + and economical method of securing the above facilities, and the + Association has expressed its satisfaction with the arrangement as in + line with the educational features which they provide for their + members. + + "During the year 1909, 215 lectures were delivered at various points + throughout the United States." + +The Bureau of Explosives, of the American Railway Association, and the +Bureau of Mines, of the United States Geological Survey, were +independent products of a general agitation due to the appreciation by a +limited number of public-spirited citizens of the gravity of the +"explosive" problem. It is the plain duty of the average citizen to +become familiar with work of this kind prosecuted in his behalf. He may +be able to help the work by assisting to overcome misguided opposition +to it. Evidences of this opposition may be noted in the efforts of some +shippers to avoid the expense of providing suitable shipping containers +for explosives and inflammable articles, and in the threats of miners' +labor unions to strike rather than use permissible explosives instead of +black powder in mining coal in gaseous or dusty mines. + +Too much credit cannot be given Messrs. Holmes and Wilson, and other +officials of the Technologic Branch of the United States Geological +Survey, for the investigations described in this paper. They are +establishing reasonable standards for many structural materials; they +are teaching the manufacturer what he can and should produce, and the +consumer what he has a right to demand; with scientific accuracy they +are pointing the way to a conservation of our natural resources and to a +saving of life which will repay the nation many times for the cost of +their work. + +When these facts become thoroughly appreciated and digested by the +average citizen, these gentlemen and their able assistants will have no +further cause to fear the withdrawal of financial or moral support for +their work. + + +HERBERT M. WILSON, M. Am. Soc. C. E. (by letter).--The Fuel Division of +the United States Geological Survey has given considerable attention to +the use of peat as a fuel for combustion under boiler furnaces, in gas +producers, and for other purposes. It is doubtless to this material that +Mr. Allen refers in speaking of utilizing "marsh mud for fuel," since he +refers to an address by Mr. Edward Atkinson on the subject of "Bog Fuel" +in which he characterized peat by the more popular term "marsh mud." + +In Europe, where fuel is expensive, 10,000,000 tons of peat are used +annually for fuel purposes. A preliminary and incomplete examination, +made by Mr. C. A. Davis, of the Fuel Division of the Geological Survey, +indicates that the peat beds of the United States extend throughout an +area of more than 11,000 sq. miles. The larger part of this is in New +England, New York, Minnesota, Wisconsin, New Jersey, Virginia, and other +Coastal States which contain little or no coal. It has been estimated +that this area will produce 13,000,000,000 tons of air-dried peat. + +At present peat production is in its infancy in the United States, +though there are in operation several commercial plants which find a +ready market for their product and are being operated at a profit. A +test was made at the Pittsburg plant on North Carolina peat operated in +a gas producer--the resulting producer gas being used to run a gas +engine of 150 h.p.--the load on which was measured on a switch-board. +Peat containing nearly 30% of ash and 15% of water gave 1 commercial +horse-power-hour for each 4 lb. of peat fired in the producer. Had the +peat cost $2 per ton to dig and prepare for the producer, each +horse-power-hour developed would have cost 0.4 of a cent. The fuel cost +of running an electric plant properly equipped for using peat fuel, of +even this low grade, in the gas producer would be about $4 per 100 h.p. +developed per 10-hour day. + +Equally good results were procured in tests of Florida and Michigan peat +operated in the gas producer. The investigations of peat under Mr. Davis +include studies of simple commercial methods of drying, the chemical and +fuel value, analyses of the peat, studies of the mechanical methods of +digging and disintegrating the peat, and physical tests to determine the +strength of air-dried peat to support a load. + +The calorific value of peat, as shown by numerous analyses made by the +United States Geological Survey, runs from about 7,500 to nearly 11,000 +B.t.u., moisture free, including the ash, which varies from less than 2% +to 20%, the latter being considered in Europe the limit of commercial +use for fuel. Analyses of 25 samples of peat from Florida, within these +limits as to ash, show a range of from 8,269 to 10,865 B.t.u., only four +of the series being below 9,000 B.t.u., and four exceeding 10,500 +B.t.u., moisture free. Such fuel in Florida is likely to be utilized +soon, since it only needs to be dug and dried in order to render it fit +for the furnace or gas producer. Many bituminous coals now used +commercially have fuel value as low as 11,000 B.t.u., moisture free, and +with maximum ash content of 20%; buckwheat anthracite averages near the +same figures, often running as high as 24% ash. + +One bulletin concerning the peats of Maine has been published, and +another, concerning the peat industries of the United States, is in +course of publication. + +Mr. Bartoccini asks whether it would not be possible for the United +States Geological Survey to enforce rules which would prevent the +existence of conditions such as occurred at the mine disaster of Cherry, +Ill. + +The United States Government has no police power within the States, and +it is not within its province to enact or enforce rules or laws, or even +to make police inspection regarding the methods of operating mining +properties. The province of the mine accidents investigations and that +of its successor, the Bureau of Mines, is, within the States, like that +of other and similar Government bureaus in the Interior Department, the +Department of Agriculture, and other Federal departments, merely to +investigate and disseminate information. It remains for the States to +enact laws and rules applying the remedies which may be indicated as a +result of Federal investigation. + +Investigations are now in progress and tests are being conducted with a +view to issuing circulars concerning the methods of fighting mine fires, +the installation of telephones and other means of signaling, and other +subjects of the kind to which Mr. Bartoccini refers. + +Much as the writer appreciates the kindly and sympathetic spirit of the +discussion of Messrs. Allen and Bartoccini, he appreciates even more +that of Colonel Dunn and Mr. Stott, who are recognized authorities +regarding the subjects they discuss, and of Messrs. Kreisinger and +Snelling, who have added materially to the details presented in the +paper relative to the particular investigations of which they have +charge in Pittsburg. + +Mr. Snelling's reference to the use of explosives in blasting operations +should be of interest to all civil engineers, as well as to mining +engineers, as should Colonel Dunn's discussion concerning the means +adopted to safeguard the transportation of explosives. + +Since the presentation of the paper, Congress has enacted a law +establishing, in the Department of the Interior, a United States Bureau +of Mines. To this Bureau have been transferred from the Geological +Survey the fuel-testing and the mine accidents investigations described +in this paper. To the writer it seems a matter for deep regret that the +investigations of the structural materials belonging to and for the use +of the United States, were not also transferred to the same Bureau. On +the last day of the session of Congress, a conference report transferred +these from the Geological Survey to the Bureau of Standards. It is +doubtful whether the continuation of these investigations in that +Bureau, presided over as it is by physicists and chemists of high +scientific attainments, will be of as immediate value to engineers and +to those engaged in building and engineering construction as they would +in the Bureau of Mines, charged as it is with the investigations +pertinent to the mining and quarrying industries, and having in its +employ mining, mechanical, and civil engineers. + + +FOOTNOTES + + [Footnote 1: Presented at the meeting of April 20th, 1910.] + + [Footnote 2: "Coal Mine Accidents," by Clarence Hall and Walter O. + Snelling. Bulletin No. 333, U.S. Geological Survey, Washington, D.C.] + + [Footnote 3: "The Explosibility of Coal Dust," by George S. Rice and + others. Bulletin No. * * *, U.S. Geological Survey.] + + [Footnote 4: "Notes on Explosives, Mine Gases and Dusts," by Rollin + Thomas Chamberlin. Bulletin No. 383, U.S. Geological Survey, 1909.] + + [Footnote 5: "Prevention of Mine Explosions," by Victor Watteyne, Carl + Meissner, and Arthur Desborough. Bulletin No. 369, U.S. Geological + Survey.] + + [Footnote 6: With a view to obtaining a dust of uniform purity and + inflammability.] + + [Footnote 7: "The Primer of Explosives," by C. E. Munroe and Clarence + Hall. Bulletin No. 423, U.S. Geological Survey, 1909.] + + [Footnote 8: "Tests of Permissible Explosives," by Clarence Hall, + W. O. Snelling, S. P. Howell, and J. J. Rutledge. Bulletin No. * * *, + U.S. Geological Survey.] + + [Footnote 9: "Structural Materials Testing Laboratories," by Richard + L. Humphrey, Bulletin No. 329. U.S. Geological Survey, 1908; + "Portland Cement Mortars and their Constituent Materials," by Richard + L. Humphrey and William Jordan, Jr., Bulletin No. 331, U.S. Geological + Survey, 1908; "Strength of Concrete Beams," by Richard L. Humphrey, + Bulletin No. 344, U.S. Geological Survey, 1908.] + + [Footnote 10: "Fire Resistive Properties of Various Building + Materials," by Richard L. Humphrey, Bulletin No. 370, U.S. Geological + Survey, 1909.] + + [Footnote 11: "Purchasing Coal Under Government Specifications," by + J. S. Burrows, Bulletin No. 378, U.S. Geological Survey, 1909.] + + [Footnote 12: "Experimental Work in the Chemical Laboratory," by N. W. + Lord, Bulletin No. 323, U.S. Geological Survey, 1907: "Operations of + the Coal Testing Plant, St. Louis, Mo." Professional Paper No. 48, + U.S. Geological Survey, 1906.] + + [Footnote 13: Also Bulletins Nos. 290, 332, 334, 363, 366, 367, 373, + 402, 403, and 412, U.S. Geological Survey.] + + [Footnote 14: "Tests of Coal for House Heating Boilers," by D. T. + Randall, Bulletin No. 336, U.S. Geological Survey, 1908.] + + [Footnote 15: "The Smokeless Combustion of Coal," by D. T. Randall and + H. W. Weeks, Bulletin No. 373, U.S. Geological Survey, 1909.] + + [Footnote 16: "The Flow of Heat through Furnace Walls," by W. T. Ray + and H. Kreisinger. Bulletin (in press), U.S. Geological Survey.] + + [Footnote 17: The assumption is made that a metal tube free from scale + will remain almost as cool as the water; actual measurements with + thermo-couples have indicated the correctness of this assumption in + the majority of cases.] + + [Footnote 18: "Heat Transmission into Steam Boilers," by W. T. Ray and + H. Kreisinger, Bulletin (in press), U.S. Geological Survey.] + + [Footnote 19: "The Producer Gas Power Plant," by R. H. Fernald, + Bulletin No. 416, U.S. Geological Survey, 1909; also Professional + Paper No. 48 and Bulletins Nos. 290, 316, 332, and 416.] + + [Footnote 20: A Taylor up-draft pressure producer, made by R. D. Wood + and Company, Philadelphia, Pa.] + + [Footnote 21: "Coal Testing Plant, St. Louis, Mo.," by R. H. Fernald, + Professional Paper No. 48, Vol. III, U.S. Geological Survey, 1906.] + + [Footnote 22: A report of these tests may be found in Bulletin No. + * * *, U.S. Geological Survey.] + + [Footnote 23: "Illuminating Gas Coals," by A. H. White and Perry + Barker, U.S. Geological Survey.] + + [Footnote 24: "Gasoline and Alcohol Tests," by R. M. Strong, Bulletin + No. 392, U.S. Geological Survey, 1909.] + + [Footnote 25: "Washing and Coking Tests," by Richard Moldenke, A. W. + Belden and G. R. Delamater, Bulletin No. 336, U.S. Geological Survey, + 1908; also, "Washing and Coking Tests at Denver, Colo.," by A. W. + Belden and G. R. Delamater, Bulletin No. 368, U.S. Geological Survey, + 1909.] + + [Footnote 26: U.S. Geological Survey, Professional Paper No. 48, Pt. + III, and Bulletins Nos. 290, 332, 336, 368, 385, and 403.] + + [Footnote 27: Professional Paper No. 48, and Bulletins Nos. 290, 316, + 332, 343, 363, 366, 385, 402, 403, and 412, U.S. Geological Survey.] + + [Footnote 28: "Peat Deposits of Maine," by E. D. Bastin and C. A. + Davis. Bulletin No. 376, U.S. Geological Survey, 1909.] + + [Footnote 29: U.S. Geological Survey, Pittsburg, Pa.] + + [Footnote 30: Chief Explosives Chemist, U.S. Geological Survey.] + + [Footnote 31: Lieutenant-Colonel, Ordnance Dept., U. S. A.] + + * * * * * + * * * * + * * * * * + +[Errata: + + [Fig. 3. caption] + SAFETY LAMP TESTING GALLERY + _text reads "SAFTY"_ + + [Mine-Rescue Training] + experienced in rescue operations and familiar / with the conditions + existing after mine disasters + _text reads "familar"_ + + so as to determine, if possible, the progress of combustion (Fig. 1, + Plate XVIII). + _text reads "Pate XVIII"_ + + The chemical analyses of the coals + _text reads "anaylses"_ ] + + + + + +End of the Project Gutenberg EBook of Transactions of the American Society +of Civil Engineers, vol. LXX, Dec. 1910, by Herbert M. 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