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| author | Roger Frank <rfrank@pglaf.org> | 2025-10-15 05:32:41 -0700 |
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| committer | Roger Frank <rfrank@pglaf.org> | 2025-10-15 05:32:41 -0700 |
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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/9076-8.txt b/9076-8.txt new file mode 100644 index 0000000..708a2cf --- /dev/null +++ b/9076-8.txt @@ -0,0 +1,4272 @@ +The Project Gutenberg EBook of Scientific American Supplement, No. 433, +April 19, 1884, by Various + +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: Scientific American Supplement, No. 433, April 19, 1884 + +Author: Various + +Posting Date: October 10, 2012 [EBook #9076] +Release Date: October, 2005 +First Posted: September 3, 2003 + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN SUPPL., NO. 433 *** + + + + +Produced by J. Niehof, D. Kretz, J. Sutherland, and +Distributed Proofreaders + + + + + + + + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 433 + + + + +NEW YORK, APRIL 19, 1884 + +Scientific American Supplement. Vol. XVII, No. 433. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + + * * * * * + +TABLE OF CONTENTS. + +I. CHEMISTRY, METALLURGY, ETC.--New Analogy between + Solids, Liquids, and Gases. + + Hydrogen Amalgam. + + Treatment of Ores by Electrolysis.--By M. KILIANI. + +II. ENGINEERING, AND MECHANICS.--Electric Railway at Vienna.--With + engraving. + + Instruction in Mechanical Engineering.--Technical and trade + education.--A course of study sketched out.--By Prof. R.H. + THURSTON. + + Improved Double Boiler.--3 figures. + + The Gardner Machine Gun.--With three engravings showing the + single barrel, two barrel, and five barrel guns. + + Climbing Tricycles. + + Submarine Explorations.--Voyage of the Talisman.--The Thibaudier + sounding apparatus.--With map, diagrams, and engravings. + + Jamieson's Cable Grapnel.--With engraving. + + A Threaded Set Collar. + +III. TECHNOLOGY.--Wretched Boiler Making. + + Pneumatic Malting.--With full description of the most improved + methods and apparatus.--Numerous figures. + + Reducing and Enlarging Plaster Casts. + + Stripping the Film from Gelatine Negatives. + +IV. ELECTRICITY.--Non-sparking Key. + + New Instruments for Measuring Electric Currents and Electromotive + Force.--By MESSRS. K.E. CROMPTON and GISBERT + KAPP.--Paper read before the Society of Telegraph Engineers.--With + several engravings. + + When Does the Electric Shock Become Fatal? + +V. ART AND ARCHÆOLOGY.--Robert Cauer's Statute of Lorelei.--With + engraving. + + The Pyramids of Meroe.--With engraving. + +VI. ASTRONOMY AND METEOROLOGY.--The Red Sky.--Cause of + the same explained by the Department of Meteorology. + + A Theory of Cometary Phenomena. + + On Comets.--By FURMAN LEAMING, M.D. + +VII. NATURAL HISTORY.--The Prolificness of the Oyster. + + Coarse Food for Pigs. + +VIII. BOTANY, HORTICULTURE, ETC.--Forms of Ivy.--With + several engravings. + + Propagating Roses. + + A Few of the Best Inulas.--With engraving. + + Fruit Growing.--By P.H. FOSTER. + +IX. MEDICINE, HYGIENE, ETC.--A People without Consumption, + and Some Account of Their Country, the Cumberland Tableland. + --By E.M. WIGHT. + + The Treatment of Habitual Constipation. + +X. MISCELLANEOUS.--The French Scientific Station at Cape Horn. + +XI. BIOGRAPHY.--The Late Maori Chief, Mete Kingi.--With portrait. + + * * * * * + + + + +THE FRENCH SCIENTIFIC STATION AT CAPE HORN. + + +In 1875 Lieutenant Weyprecht of the Austrian navy called the attention +of scientific men to the desirability of having an organized and +continual system of hourly meteorological and magnetic observations +around the poles. In 1879 the first conference of what was termed the +International Polar Congress was held at Hamburg. Delegates from eight +nations were present--Germany, Austria, Denmark, France, Holland, +Norway, Russia, and Sweden. + +The congress then settled upon a programme whose features were: 1. To +establish general principles and fixed laws in regard to the pressure +of the atmosphere, the distribution and variation of temperature, +atmospheric currents, climatic characteristics. 2. To assist the +prediction of the course and occurrence of storms. 3. To assist the +study of the disturbances of the magnetic elements and their relations +to the auroral light and sun spots. 4. To study the distribution of +the magnetic force and its secular and other changes. 5. To study the +distribution of heat and submarine currents in the polar regions. 6. To +obtain certain dimensions in accord with recent methods. Finally, to +collect observations and specimens in the domain of zoology, botany, +geology, etc. + +The representatives of the various nations had several conferences +later, and by the 1st of May, 1881, there were sufficient subscribers to +justify the establishment of eight Arctic stations. + +France entered actively in this work later, and its first expedition was +to Orange Bay and Cape Horn, under the surveillance and direction of +the Academy of Sciences, Paris, and responsible to the Secretary of the +Navy. On the 6th of September, 1882, this scientific corps established +itself in Orange Bay, near Cape Horn, and energetically began its +serious labors, and by October 22 the greater part of their preliminary +preparations was completed, comprising the erection of a magnetic +observatory, an astronomic observatory, a room for the determination of +the carbonic anhydride of the air, another for the sea register, and +a bridge 92 feet long, photographic laboratory, barometer room, and +buildings for the men, food, and appurtenances, together with a +laboratory of natural history. + +In short, in spite of persistent rains and the difficulties of the +situation, from September 8 to October 22 they erected an establishment +of which the different parts, fastened, as it were, to the flank of a +steep hill, covered 450 square meters (4,823 square feet), and rested +upon 200 wooden piles. + +From September 26, 1882, to September 1, 1883, night and day +uninterruptedly, a watch was kept, in which the officers took part, so +that the observations might be regularly made and recorded. Every four +hours a series of direct magnetic and meteorological observations was +made, from hour to hour meteorological notes were taken, the rise and +fall of the sea recorded, and these were frequently multiplied by +observations every quarter of an hour; the longitude and latitude were +exactly determined, a number of additions to the catalogue of the fixed +stars for the southern heavens made, and numerous specimens in natural +history collected. + +The apparatus employed by the expedition for the registration of the +magnetic elements was devised by M. Mascart, by which the variations +of the three elements are inscribed upon a sheet of paper covered with +gelatine bromide, inclination, vertical and horizontal components, with +a certainty which is shown by the 330 diurnal curves brought back from +the Cape. + +The register proper is composed of a clock and a photographic frame +which descends its entire length in twenty-four hours, thus causing the +sensitized paper to pass behind a horizontal window upon which falls the +light reflected by the mirrors of the magnetic instruments. One of those +mirrors is fixed, and gives a line of reference; the other is attached +to the magnetic bar, whose slightest movements it reproduces upon the +sensitized paper. The moments when direct observations were taken were +carefully recorded. The magnetic _pavilion_ was made of wood and copper, +placed at about fifty-three feet from the dwellings or camp, near the +sea, against a wooded hill which shaded it completely; the interior +was covered with felt upon all its sides, in order to avoid as much as +possible the varying temperatures. + +The diurnal amplitude of the declination increased uniformly from the +time of their arrival in September up to December, when it obtained +its maximum of 7'40", then diminished to June, when it is no more than +2'20"; from this it increased up to the day of departure. The maximum +declination takes place toward 1 P.M., the minimum at 8:50 A.M. The +night maxima and minima are not clearly shown except in the southern +winter. + +The mean diurnal curve brings into prominence the constant diminution +of the declination and the much greater importance of the perturbations +during the summer months. These means, combined with the 300 absolute +determinations, give 4' as the annual change of the declination. + +M. Mascart's apparatus proved to be wonderfully useful in recording the +rapid and slight perturbations of the magnet. Comparisons between the +magnetic and atmospheric perturbations gave no result. There was, +however, little stormy weather and no auroral displays. This latter +phenomenon, according to the English missionaries, is rarely observed in +Tierra del Fuego. + +The electrometer used at the Cape was founded upon the principle +developed by Sir William Thomson. The atmospheric electricity is +gathered up by means of a thin thread of water, which flows from a +large brass reservoir furnished with a metallic tube 6.5 feet long. The +reservoir is placed upon glass supports isolated by sulphuric acid, and +is connected to the electrometer by a thread of metal which enters a +glass vessel containing sulphuric acid; into the same vessel enters a +platinum wire coming from the aluminum needle. Only 3,000 observations +were given by the photographic register, due to the fact that the +instruments were not fully protected against constant wet and cold. + +Besides these observations direct observations of the magnetometer were +made, and the absolute determination of the elements of terrestrial +magnetism attempted. + +On the 17th of November, 1882, a severe magnetic disturbance occurred, +lasting from 12 M. until 3 P.M., which in three hours changed the +declination 42'. The same perturbation was felt in Europe, and the +comparison of the observations in the two hemispheres will prove +instructive. + + * * * * * + + + + +THE ELECTRIC RAILWAY AT VIENNA. + + +The total length of this railway, which extended from the Eiskeller in +the Schwimmschul-Allee to the northern entrance of the Rotunda, was +1528.3 meters; the gauge was 1 meter, and 60 per cent. of the length +consisted of tangents, the remaining 40 per cent. being mostly curves +of 250 meters radius. The gradients, three in number, were very small, +averaging about 1:750. + +Two generating dynamos were used, which were coupled in parallel +circuit, but in such a manner that the difference of potential in both +machines remained the same at all times. This was accomplished by the +well known method of coupling introduced by Siemens and Halske, in which +the current of one machine excites the field of the other. + +Although the railroad was not built with a view of obtaining a high +efficiency, an electro-motive force of only 150 volts being used, a +mechanical efficiency of 50 per cent. was nevertheless obtained, both +with one generator and one car with thirty passengers, as well as with +two generators and two cars with sixty passengers; while with two +generators and three cars (two of them having motors) the same result +was shown. + +[Illustration: THE ELECTRIC RAILWAY AT VIENNA.] + +The curves obtained by the apparatus that recorded the current showed +very plainly the action within the machines when the cars were started +or set in motion; at first, the current rose rapidly to a very high +figure, and then declined gradually to a fixed point, which corresponded +to the regular rate of speed. The tractive power, therefore, increases +rapidly to a value far exceeding the frictional resistances, but this +surplus energy serves to increase the velocity, and disappears as soon +as a uniform velocity is reached. + +The average speed, both with one and three cars, was 30 kilometers per +hour.--_Zeitsch. f. Elektrotechnik_. + + * * * * * + + + + +INSTRUCTION IN MECHANICAL ENGINEERING. + +By Professor R. H. THURSTON. + + +The writer has often been asked by correspondents interested in +the matter of technical and trade education to outline a course of +instruction in mechanical engineering, such as would represent his +idea of a tolerably complete system of preparation for entrance into +practice. The synopsis given at the end of this article was prepared +in the spring of 1871, when the writer was on duty at the U.S. Naval +Academy, as Assistant Professor of Natural and Experimental Philosophy, +and, being printed, was submitted to nearly all of the then leading +mechanical engineers of the United States, for criticism, and with a +request that they would suggest such alterations and improvements as +might seem to them best. The result was general approval of the course, +substantially as here written. This outline was soon after proposed as a +basis for the course of instruction adopted at the Stevens Institute of +Technology, at Hoboken, to which institution the writer was at about +that time called. He takes pleasure in accepting a suggestion that its +publication in the SCIENTIFIC AMERICAN would be of some advantage to +many who are interested in the subject. + +The course here sketched, as will be evident on examination, includes +not only the usual preparatory studies pursued in schools of mechanical +engineering, but also advanced courses, such as can only be taught in +special schools, and only there when an unusual amount of time can be +given to the professional branches, or when post graduate courses can be +given supplementary to the general course. The complete course, as here +planned, is not taught in any existing school, so far as the writer is +aware. In his own lecture room the principal subjects, and especially +those of the first part of the work, are presented with tolerable +thoroughness; but many of the less essential portions are necessarily +greatly abridged. As time can be found for the extension of the course, +and as students come forward better prepared for their work, the earlier +part of the subject is more and more completely developed, and the +advanced portions are taken up in greater and greater detail, each year +giving opportunity to advance beyond the limits set during the preceding +year. + +Some parts of this scheme are evidently introductory to advanced courses +of study which are to be taken up by specialists, each one being adapted +to the special instruction of a class of students who, while pursuing +it, do not usually take up the other and parallel courses. Thus, a +course of instruction in Railroad Engineering, a course in Marine +Engineering, or a course of study in the engineering of textile +manufactures, may be arranged to follow the general course, and the +student will enter upon one or another of these advanced courses as his +talents, interests, or personal inclinations may dictate. At the Stevens +Institute of Technology, two such courses--Electrical and Marine +Engineering--are now organized as supplementary of the general course, +and are pursued by all students taking the degree of Mechanical +Engineer. These courses, as there given, however, are not fairly +representative of the idea of the writer, as above expressed, since the +time available in general course is far too limited to permit them to be +developed beyond the elements, or to be made, in the true sense of the +term, advanced professional courses. Such advanced courses as the writer +has proposed must be far more extended, and should occupy the whole +attention of the student for the time. Such courses should be given in +separate departments under the direction of a General Director of the +professional courses, who should be competent to determine the extent of +each, and to prevent the encroachment of the one upon another; but they +should each be under the immediate charge of a specialist capable +of giving instruction in the branch assigned to him, in both the +theoretical and purely scientific, and the practical and constructive +sides of the work. Every such school should be organized in such a +manner that one mind, familiar with the theory and the practice of the +professional branches taught, should be charged with the duty of giving +general direction to the policy of the institution and of directing +the several lines of work confided to specialists in the different +departments. It is only by careful and complete organization in this, as +in every business, that the best work can be done at least expense in +time and capital. + +In this course of instruction in Mechanical Engineering it will be +observed that the writer has incorporated the scheme of a workshop +course. This is done, not at all with the idea that a school of +mechanical engineering is to be regarded as a "trade school," but that +every engineer should have some acquaintance with the tools and the +methods of work upon which the success of his own work is so largely +dependent. If the mechanical engineer can acquire such knowledge in the +more complete course of instruction of the trade school, either before +or after his attendance at the technical school, it will be greatly to +his advantage. The technical school has, however, a distinct field; and +its province is not to be confounded with that of the trade school. +The former is devoted to instruction in the theory and practice of a +profession which calls for service upon the men from the latter--which +makes demand upon a hundred trades--in the prosecution of its designs. +The latter teaches, simply, the practical methods of either of the +trades subsidiary to the several branches of engineering, with only so +much of science as is essential to the intelligent use of the tools and +the successful application of the methods of work of the trade taught. +The distinction between the two departments of education, both of which +are of comparatively modern date, is not always appreciated in the +United States, although always observed in those countries of Europe +in which technical and trade education have been longest pursued as +essential branches of popular instruction. Throughout France and +Germany, every large town has its trade schools, in which the trades +most generally pursued in the place are systematically taught; and every +large city has its technical school, in which the several professions +allied to engineering are studied with special development of those to +which the conditions prevailing at the place give most prominence and +local importance. + +A course of trade instruction, as the writer would organize it, would +consist, first, in the teaching of the apprentice the use of the tools +of his trade, the nature of its materials, and the construction and +operation of the machinery employed in its prosecution. He would next be +taught how to shape the simpler geometrical forms in the materials of +his trade, getting out a straight prism, a cylinder, a pyramid, or a +sphere, of such size and form as may be convenient; getting lines and +planes at right angles, or working to miter; practicing the working of +his "job" to definite size, and to the forms given by drawings, which +drawings should be made by the apprentice himself. When he is able to +do good work of this kind, he should attempt larger work, and the +construction of parts of structures involving exact fitting and special +manipulations. The course, finally, should conclude with exercises in +the construction and erection of complete structures and in the making +of peculiar details, such as are regarded by the average workman +as remarkable "_tours de force_." The trade school usually gives +instruction in the common school branches of education, and especially +in drawing, free-hand and mechanical, carrying them as far as the +successful prosecution of the trade requires. The higher mathematics, +and advanced courses in physics and chemistry, always taught in schools +of engineering, are not taught in the trade school, as a rule; although +introduced into those larger schools of this class in which the aim is +to train managers and proprietors, as well as workmen. This is done in +many European schools. + +As is seen above, the course of instruction in mechanical engineering +includes some trade education. The engineer is dependent upon the +machinist, the founder, the patternmaker, and other workers at the +trades, for the proper construction of the machinery and structures +designed by him. He is himself, in so far as he is an engineer, a +designer of constructions, not a constructor. He often combines, +however, the functions of the engineer, the builder, the manufacturer, +and the dealer, in his own person. No man can carry on, successfully, +any business in which he is not at home in every detail, and in which he +cannot instruct every subordinate, and cannot show every person employed +by him precisely what is wanted, and how the desired result can be best +attained. The engineer must, therefore, learn, as soon and as thoroughly +as possible, enough of the details of every art and trade, subsidiary +to his own department of engineering, to enable him to direct, with +intelligence and confidence, every operation that contributes to the +success of his work. The school of engineering should therefore be so +organized that the young engineer may be taught the elements of every +trade which is likely to find important application in his professional +work. It cannot be expected that time can be given him to make himself +an expert workman, or to acquire the special knowledge of details and +the thousand and one useful devices which are an important part of the +stock in trade of the skilled workman; but he may very quickly learn +enough to facilitate his own work greatly, and to enable him to learn +still more, with rapidity and ease, during his later professional life. +He must also, usually, learn the essential elements and principles of +each of several trades, and must study their relations to his work, and +the limitations of his methods of design and construction which they +always, to a greater or less extent, cause by their own practical or +economical limitations. He will find that his designs, his methods of +construction, and of fitting up and erecting, must always be planned +with an intelligent regard to the exigencies of the shop, as well as to +the aspect of the commercial side of every operation. This extension of +trade education for the engineer into several trades, instead of its +restriction to a single trade, as is the case in the regular trade +school, still further limits the range of his instruction in each. With +unusual talent for manipulation, he may acquire considerable knowledge +of all the subsidiary trades in a wonderfully short space of time, if he +is carefully handled by his instructors, who must evidently be experts, +each in his own trade. Even the average man who goes into such schools, +following his natural bent, may do well in the shop course, under good +arrangements as to time and character of instruction. If a man has not a +natural inclination for the business, and a natural aptitude for it, he +will make a great mistake if he goes into such a school with the hope of +doing creditable work, or of later attaining any desirable position in +the profession. + +The course of instruction, at the Stevens Institute of Technology, +includes instruction in the trades to the extent above indicated. The +original plan, as given below, included such a course of trade education +for the engineer; but it was not at once introduced. The funds +available from an endowment fund crippled by the levying of an enormous +"succession tax" by the United States government and by the cost of +needed apparatus and of unanticipated expenses, in buildings and in +organization, were insufficient to permit the complete organization +of this department. A few tools were gathered together; but skilled +mechanics could not be employed to take up the work of instruction in +the several courses. Little could therefore be done for several years in +this direction. In 1875 the writer organized a "mechanical laboratory," +with the purpose of attaining several very important objects: the +prosecution of scientific research in the various departments of +engineering work; the creation of an organization that should give +students an opportunity to learn the methods of research most usefully +employed in such investigations; the assistance of members of the +profession, and business organizations in the attempt to solve such +questions, involving scientific research, as are continually arising in +the course of business; the employment of students who had done +good work in their college course, when they so desire, in work of +investigation with a view to giving them such knowledge of this peculiar +line of work as should make them capable of directing such operations +elsewhere; and finally, but not least important of all, to secure, by +earning money in commercial work of this kind, the funds needed to carry +on those departments of the course in engineering that had been, up +to that time, less thoroughly organized than seemed desirable. This +"laboratory" was organized in 1875, the funds needed being obtained +by drawing upon loans offered by friends of the movement and by the +"Director." + +It was not until the year 1878, therefore, that it became possible to +attempt the organization of the shop course; and it was then only by the +writer assuming personal responsibility for its expenses that the plan +could be entered upon. As then organized--in the autumn of 1878--a +superintendent of the workshop had general direction of the trade +department of the school. He was instructed to submit to the writer +plans, in detail, for a regular course of shop instruction, and was +given as assistants a skilled mechanic of unusual experience and +ability, whose compensation was paid from the mechanical laboratory +funds, and guaranteed by the writer personally, and another aid whose +services were paid for partly by the Institute and partly as above. The +pay of the superintendent was similarly assured. This scheme had been +barely entered upon when the illness of the writer compelled him to +temporarily give up his work, and the direction of the new organization +fell into other hands, although the department was carried on, as above, +for a year or more after this event occurred. + +The plan did not fall through; the course of instruction was +incorporated into the college course, and its success was finally +assured by the growth of the school and a corresponding growth of its +income, and, especially, by the liberality of President Morton, who met +expenses to the amount of many thousands of dollars by drawing upon his +own bank account. The department was by him completely organized, with +an energetic head, and needed support was given in funds and by a force +of skilled instructors. This school is now in successful operation. +This course now also includes the systematic instruction of students in +experimental work, and the objects sought by the writer in the creation +of a "mechanical laboratory" are thus more fully attained than they +could have possibly been otherwise. It is to be hoped that, at +some future time, when the splendid bequest of Mr. Stevens may be +supplemented by gifts from other equally philanthropic and intelligent +friends of technical education, among the alumni of the school and +others, this germ of a trade school maybe developed into a complete +institution for instruction in the arts and trades of engineering, and +may thus be rendered vastly more useful by meeting the great want, in +this locality, of a real trade school, as well as fill the requirements +of the establishment of which it forms a part, by giving such trade +education as the engineer needs and can get time to acquire. + +The establishment of advanced courses of special instruction in +the principal branches of mechanical engineering may, if properly +"dovetailed" into the organization, be made a means of somewhat +relieving the pressure that must be expected to be felt in the attempt +to carry out such a course as is outlined below. The post-graduate +or other special departments of instruction, in which, for example, +railroad engineering, marine engineering, and the engineering of cotton, +woolen, or silk manufactures, are to be taught, may be so organized that +some of the lectures of the general course may be transferred to them, +and the instructors in the latter course thus relieved, while the +subjects so taught, being treated by specialists, may be developed more +efficiently and more economically. + +Outlines of these advanced courses, as well as of the courses in trade +instruction comprehended in the full scheme of mechanical engineering +courses laid out by the writer a dozen years ago, and as since recast, +might be here given, but their presentation would occupy too much space, +and they are for the present omitted. + +The course of instruction in this branch of engineering, at the Stevens +Institute of Technology, is supplemented by "Inspection Tours," which +are undertaken by the graduating class toward the close of the last +year, under the guidance of their instructors, in which expeditions they +make the round of the leading shops in the country, within a radius of +several hundred miles, often, and thus get an idea of what is meant by +real business, and obtain some notion of the extent of the field of work +into which they are about to enter, as well as of the importance of +that work and the standing of their profession among the others of the +learned professions with which that of engineering has now come to be +classed. + +At the close of the course of instruction, as originally proposed, and +as now carried out, the student prepares a "graduating thesis," in which +he is expected to show good evidence that he has profited well by the +opportunities which have been given him to secure a good professional +education. These theses are papers of, usually, considerable extent, and +are written upon subjects chosen by the student himself, either with or +without consultation with the instructor. The most valuable of +these productions are those which present the results of original +investigations of problems arising in practice or scientific research +in lines bearing upon the work of the engineer. In many cases, the +work thus done has been found to be of very great value, supplying +information greatly needed in certain departments, and which had +previously been entirely wanting, or only partially and unsatisfactorily +given by authorities. Other theses of great value present a systematic +outline of existing knowledge of some subject which had never before +been brought into useful form, or made in any way accessible to the +practitioner. In nearly all cases, the student is led to make the +investigation by the bent of his own mind, or by the desire to do work +that may be of service to him in the practice of his profession. All +theses are expected to be made complete and satisfactory to the head +of department of Engineering before his signature is appended to the +diploma which is finally issued to the graduating student. These +preliminaries being completed, and the examinations having been reported +as in all respects satisfactory, the degree of Mechanical Engineer is +conferred upon the aspirant, and he is thus formally inducted into the +ranks of the profession. + + +COURSE OF INSTRUCTION IN MECHANICAL ENGINEERING. + + +Robert H. Thurston--July, 1871. + +I. + +MATERIALS USED IN ENGINEERING.--Classification, Origin, and Preparation +(where not given in course of Technical Chemistry), Uses, Cost. + +_Strength and Elasticity_.--Theory (with experimental illustrations), +reviewed, and tensile, transverse and torsional resistance determined. + +_Forms_ of greatest strength determined. _Testing_ materials. + +_Applications_.--Foundations, Framing in wood and metal. + +FRICTION.--Discussion from Rational Mechanics, reviewed and extended. + +_Lubricants_ treated with materials above. + +Experimental determination of "coefficients of friction." + +II. + +TOOLS.--Forms for working wood and metals. Principles involved in their +use. + +Principles of pattern making, moulding, smith and machinists' work so +far as they modify design. + +Exercises in Workshops in mechanical manipulation. + +Estimates of _cost_ (stock and labor). + +MACHINERY AND MILL WORK.--Theory of machines. Construction. Kinematics +applied. Stresses, calculated and traced. Work of machines. Selection +of materials for the several parts. Determination of _proportions_ of +details, and of _forms_ as modified by difficulties of construction. + +Regulators, Dynamometers, Pneumatic and Hydraulic machinery. Determining +_moduli_ of machines. + +POWER, transmission by gearing, belting, water, compressed air, etc. + +LOADS, transportation. + +III. + +HISTORY AND PRESENT FORMS OF THE PRIME MOVERS. + +_Windmills_, their theory, construction, and application. + +_Water Wheels_. Theory, construction, application, testing, and +comparison of principal types. + +_Air, Gas, and Electric Engines_, similarly treated. + +STEAM ENGINES.--Classification. [Marine (merchant) Engine assumed as +representative type.] Theory. Construction, including general design, +form and proportion of details. + +_Boilers_ similarly considered. Estimates of _cost_. + +_Comparison_ of principal types of Engines and Boilers. Management and +repairing. Testing and recording performance. + +IV. + +MOTORS APPLIED to Mills. Estimation of required power and of _cost_. + +Railroads. Study of Railroad machinery. + +Ships. Structure of Iron Ships and rudiments of Naval architecture and +Ship propulsion. + +PLANNING Machine shops, Boiler shops, Foundries, and manufactories of +textile fabrics. Estimating _cost_. + +LECTURES BY EXPERTS. + +GENERAL SUMMARY of principal facts, and natural laws, upon the thorough +knowledge of which successful practice is based; and general _resume_ +of principles of business which must be familiar to the practicing +engineer. + +V. + +GRADUATING THESES. + +GRADUATION. + +Accompanying the above are courses of instruction in higher mathematics, +graphics, physics, chemistry, and the modern languages and literatures. + + * * * * * + + + + +IMPROVED DOUBLE BOILER. + + +The operation of boiling substances under pressure with more or less +dilute sulphuric or sulphurous acid forms a necessary stage of several +important manufactures, such as the production of paper from wood, the +extraction of sugar, etc. A serious difficulty attending this process +arises from the destructive action of the acid upon the boiler or +chamber in which the operation is carried on, and as this vessel, which +is generally of large dimensions, is exposed to considerable pressures, +it is necessarily constructed of iron or some other sufficiently +resisting metal. An ingenious method of avoiding this difficulty has +been devised, we believe in Germany, and has been put into practice with +a certain amount of success. It consists in lining the iron boiler with +a covering of lead, caused by fusion to unite firmly to the walls of the +boiler, and thus to protect it from the action of the acid. No trouble, +it is stated, is found to arise from the difference in expansion of the +two metals, which, moreover, adhere fairly well; but, on the other hand, +we believe it does actually occur that the repairs to this lead lining +are numerous, tedious, and costly of execution, so that the system can +scarcely be regarded as meeting the requirements of the manufacturer. +It is to secure all the advantages possessed by a lead-lined vessel, +without the drawback of frequent and expensive repairs, that the +digester, of which we annex illustrations, has been devised by Mr. +George Knowles, of Billiter House, Billiter Street. It consists of a +closed iron cylindrical vessel suitable for boiling under pressure, and +containing a second vessel open at the top, and of such a diameter as to +leave an annular space between it and the walls of the outer shell. This +inner receiver, which may be made of lead, glass, pottery, or any +other suitable material, contains the substance to be treated and the +sulphurous acid or other solution in which it is to be boiled. The +annular space between the two vessels is filled with water to the same +level as the solution in the receiver, and the latter is provided with +suitable pipes or coils, in which steam is caused to circulate for +the purpose of raising the solution of the desired temperature, and +effecting the digesting process. At the same time any steam generated +collects in the upper part of the boiler, and maintains an equal +pressure within the whole apparatus. Figs. 1 to 3 show the arrangement +clearly. Within the boiler, a, is placed the receiver, b, of pottery, +lead, or other material, leaving an annular space between it and the +boiler; this space is filled with water. The receiver, b, is furnished +with a series of pipes, in which steam or hot water circulates, to heat +the charge to the desired temperature. These pipes may be arranged +either in coils, as shown at d, Fig. 1, or vertically at d, Fig. 3. The +latter are provided with inner return pipes, so that any condensed water +accumulating at the bottom may be forced up the inner pipes by the +steam pressure and escape at the top. The vessel is charged through the +manhole, e, and the hopper, c, provided with a perforated cover, and is +discharged at the bottom by the valve, f, shown in Figs. 2 and 3. The +upper part of the boiler serves as a steam dome, and the pressure on the +liquid in the receiver and on the water in the annular space is thereby +maintained uniform. The necessary fittings for showing the pressure +in the vessel, water level indicator, safety valve, cocks for testing +solutions, etc., are of course added to the apparatus, but are not +indicated in the drawing. The arrangement appears to us to possess +considerable merit, and we shall refer to it again on another occasion, +after experiments have been made to test its efficiency.--_Engineering_. + +[Illustration: IMPROVED DOUBLE BOILER.] + + * * * * * + + + + +THE GARDNER MACHINE GUN. + + +[Illustration: FIG. 1.--SINGLE BARREL GARDNER MACHINE GUN.] + +The mechanism by which the various functions of loading, firing, and +extracting are performed is contained in a rectangular gun metal case, +varying in dimensions with the number of barrels in the arm. In the +single barrel gun the size of this case is 14 inches in length, 5½ +inches in depth, and 2½ inches in width. The top of the box is hinged, +so that easy access can be had to the mechanism, which consists of a +lock, the cartridge carrier, and the devices for actuating them. In the +multiple barrel guns, the frames which, with the transverse bar at the +end, hold the barrels in place, form the sides of the mechanism chamber, +in the front end of which the barrels are screwed. The mechanism is +actuated by a cam shaft worked by a hand crank on one side of the +chamber. By this means the locks are driven backward and forward, +the latter motion forcing the cartridges into place, and the former +withdrawing the empty cartridge case after firing. The extractor hook +pivoted to the lock plunger rises, as the lock advances, over the rim of +the case, but is rigid as the lock is withdrawn, so that the action is +a positive one. The cartridges, which are contained in a suitable +frame attached to the forward part of the breech chamber, pass through +openings in the top plate of the latter, an efficient distribution being +secured by means of a valve having a transverse motion. Each cartridge +as it falls is brought into the axis of the barrel and the plunger, +while the advance motion of the lock forces them into position. In the +five-barrel gun illustrated by Fig. 3 the cartridge feeder contains 100 +cartridges, in five Vertical rows of 20 cartridges each, and these are +kept supplied, when firing, from supplementary holders. Fig. 1 shows the +portable rest manufactured by the Gardner Gun Company. It consists of +two wrought iron tubes, placed at right angles to each other; the front +bar can be easily unlocked, and placed in line with the trail bar, from +which project two arms, each provided with a screw that serves for the +lateral adjustment of the gun. These screws are so arranged as to allow +for an oscillating motion of the gun through any distance up to 15 deg. +The tripod mounting, used for naval as well as land purposes, is shown +in Fig. 2, which illustrates the two barrel gun complete. The five +barrel gun, Fig. 3, is shown mounted on a similar tripod. The length of +this weapon over all is 53.5 inches, the barrels (Henry system) are 33 +inches long, with seven grooves of a uniform twist of one turn in 22 +inches. + +[Illustration: Fig. 2.--TWO BARREL GARDNER GUN.] + +Gardener's five barrel gun in the course of one of the trials fired +16,754 rounds with only 24 jams, and in rapid firing reached a maximum +of 330 shots in 30 seconds. The two barrel gun fired 6,929 rounds +without any jam; the last 3,000 being in 11 minutes 39 seconds, without +any cleaning or oiling.--_Engineering_. + +[Illustration: Fig. 3.--FIVE BARREL GARDNER GUN.] + + * * * * * + + + + +CLIMBING TRICYCLES. + + +The cycle trade is one which has been developed with great rapidity +within the last ten years, and, like all new industries, has called +forth a considerable amount of ingenuity and skill on the part of those +engaged in it. We cannot help thinking, however, that much of this +ingenuity has been misplaced, and that instead of striving after new +forms involving considerable complication and weight, it would have +been better and more profitable if manufacturers had moderated their +aspirations, and aimed at greater simplicity of design; for it must +be remembered that cyclists are, as a rule, without the slightest +mechanical knowledge, while the machines themselves are subject to very +hard usage and considerable wear and tear in traveling over the +ordinary roads in this country. We refer, of course, more especially to +tricycles, which in one form or another are fast taking the place of +bicycles, and which promise to assume an important position in every +day locomotion. Hitherto one of the chief objections to the use of the +tricycle has been the great difficulty experienced in climbing hills, a +very slight ascent being sufficient to tax the powers of the rider to +such an extent as to induce if not compel him in most instances to +dismount and wheel his machine along by hand until more favorable ground +is reached. To obviate this inconvenience many makers have introduced +some arrangement of gearing speeds of two powers giving the necessary +variation for traveling up hill and on the level. We noticed, however, +one machine at the exhibition which seemed to give all that could be +desired without any gearing or chains at all. This was a direct action +tricycle shown by the National Cycle Company, of Coventry, in which the +pressure from the foot is made to bear directly upon the main axle, and +so transmitted without loss to the driving wheels on each side, the +position of the rider being arranged so that just sufficient load is +allowed to fall on the back wheel as to obtain certainty in steerage. +The weight of this machine is much less than when gearing is used, and +the friction is also considerably reduced, trials with the dynamometer +having shown that on a level, smooth road, a pull of 1 lb. readily +moved it, while with a rider in the seat 4 lb. was sufficient. On this +tricycle any ordinary hill can, it is stated, be ascended with great +ease, and as a proof of its power it was exhibited at the Stanley show +climbing over a piece of wood 8 in. high, without any momentum whatever. +We understand that at the works at Coventry a flight of stairs has been +erected, and that no difficulty is experienced in ascending them on one +of these machines.--_The Engineer_. + + * * * * * + + + + +SUBMARINE EXPLORATIONS. + +VOYAGE OF THE TALISMAN. + + +It was but a few years ago that the idea was prevalent that the seas at +great depths were immense solitudes where life exhibited itself under no +form, and where an eternal night reigned. To-day, thanks to expeditions +undertaken for the purpose of exploring the abysses of the ocean, we +know that life manifests itself abundantly over the bottom, and that +at a depth of five and six thousand meters light is distributed by +innumerable phosphorescent animals. Different nations have endeavored to +rival each other in the effort to effect these important discoveries, +and several scientific missions have been sent to different points of +the globe by the English and American governments. The French likewise +have entered with enthusiasm upon this new line of research, and for +four consecutive years, thanks to the devoted aid of the ministry of the +marine, savants have been enabled to take passage in government vessels +that were especially arranged for making submarine explorations. + +[Illustration: THE FRENCH SCIENTIFIC STEAMER TALISMAN.] + +The first French exploration, which was an experimental trip, was made +in 1880 by the Travailleur in the Gulf of Gascogne. Its unhoped +for results had so great an importance that the following year the +government decided to continue its researches, and the Travailleur was +again put at the disposal of Mr. Alph. Milne Edwards and the commission +over which he presided. Mr. Edwards traversed the Gulf of Gascogne, +visited the coast of Portugal, crossed the Strait of Gibraltar, and +explored a great portion of the Mediterranean. In 1882 the same vessel +undertook a third mission to the Atlantic Ocean, and as far as to the +Canary Islands. The Travailleur, however, being a side-wheel advice-boat +designed for doing service at the port of Rochefort, presented none +of those qualities that are requisite for performing voyages that are +necessarily of long duration. The quantity of coal that could be stored +away in her bunkers was consumed in a week, and, after that, she could +not sail far from the points where it was possible for her to coal up +again. So after her return Mr. Edwards made a request for a ship that +was larger, a good sailer, and that was capable of carrying with it a +sufficient supply of fuel for remaining a long time at sea, and that +was adapted to submarine researches. The Commission indorsed this +application, and the Minister of Instruction received it and transmitted +it to Admiral Jauréguiberry--the Minister of the Marine--who at once +gave orders that the Talisman should be fitted up and put in commission +for the new dredging expedition. This vessel, under command of Captain +Parfait, who the preceding year had occupied the same position on the +Travailleur, left the port of Rochefort on the 1st of June, 1883, having +on board Mr. Milne Edwards and the scientific commission that had been +appointed by the Minister of Public Instruction. The Talisman explored +the coasts of Portugal and Morocco, visited the Canary and Cape Verd +Islands, traversed the Sea of Sargasso, and, after a stay of some time +at the Azores, returned to France, after exploring on its way the Gulf +of Gascogne (Fig.). + +[Illustration: FIG.1.--CHART OF THE TALISMAN'S VOYAGE.] + +The magnificent collections in natural history that were collected +on this cruise, and during those of preceding years made by the +Travailleur, are, in a few days, to be exhibited at the Museum of +Natural History. We think we shall be doing a service to the readers of +this journal, in giving them some details as to the organization of the +Talisman expedition as well as to the manner in which the dredgings were +performed. + +[Illustration: FIG.2.--PLAN OF THE VESSEL.] + +The vessel, as shown by her plan in Fig. 2, had to undergo important +alterations for the cruise that she was to undertake. Her deck was +almost completely freed from artillery, since this would have encumbered +her too much. Immediately behind the bridge, in the center of the +vessel, there were placed two windlasses, one, A, to the right, and the +other, B, to the left (Fig. 2). These machines, whose mode of operation +will be explained further along, were to serve for raising and lowering +the fishing apparatus. A little further back there were constructed +two cabins, G and HH. The first of these was designed to serve as a +laboratory, and the second was arranged as quarters for the members of +the mission. + +The sounding apparatus, the Brothergood engine for actuating it, and the +electric light apparatus were placed upon the bridge. The operating +of the sounding line and of the electric light was therefore entirely +independent of that of the dredges. On the foremast, at a height of +about two meters, there was placed a crane, F, which was capable of +moving according to a horizontal plane. Its apex, as may be seen from +the plan of the boat, was capable of projecting beyond the sides of the +ship, to the left and right. To this apex was fixed a pulley over which +ran the cable that supported the dredges or bag-nets, which latter were +thus carried over the boat's sides. + +[Illustration: FIG.3.--DIAGRAM OF THE THIBAUDIER SOUNDING APPARATUS.] + +The preliminary operation in every submarine exploration consists in +exactly determining the depth of the sea immediately beneath the vessel. +To effect this object different sounding apparatus have been proposed. +As the trials that were made of these had shown that each of them +possessed quite grave defects, Mr. Thibaudier, an engineer of the navy, +installed on board the Talisman last year a new sounding apparatus which +had been constructed according to directions of his and which have given +results that are marvelous. The apparatus automatically registers the +number of meters of wire that is paid out, and as soon as the sounding +lead touches bottom, it at once stops of itself. This apparatus is shown +in Fig. 4, and a diagram of it is given in Fig. 3, so that its operation +may be better understood. The Thibaudier sounding apparatus consists of +a pulley, P (Fig. 3), over which is wound 10,000 meters of steel wire +one millimeter in diameter. From this pulley, the wire runs over a +pulley, B, exactly one meter in circumference; from thence it runs to a +carriage, A, which is movable along wooden shears, runs up over a fixed +pulley, K, and reaches the sounding lead, S, after traversing a guide, +g, where there is a small sheave upon which it can bear, whatever be the +inclination of the boat. The wheel, B, carries upon its axle an endless +screw that sets in motion two toothed wheels that indicate the number +of revolutions that it is making. One of these marks the units and the +other the hundredths (Fig. 5). This last is graduated up to 10,000 +meters. As every revolution of the wheel, B, corresponds to one meter, +the number indicated by the counter represents the depth. Upon the axle +of the winding pulley there is a break pulley, p. The brake, f, is +maneuvered by a lever, L, at whose extremity there is a cord, C, which +is made fast to the carriage, A. When, during the motions due to +rolling, the tension of the steel wire that supports the lead diminishes +or increases, the carriage slightly rises or falls, and, during these +motions, acts more or less upon the brake and consequently regulates the +velocity with which the wire unwinds. When the lead touches bottom, the +wire, being suddenly relieved from all weight (which is sometimes as +much as 70 kilos), instantly stops. + +[Illustration: FIG. 4.--GENERAL VIEW OF THE SOUNDING APPARATUS IN THE +"TALISMAN:"] + +The maneuver of this apparatus may be readily understood. The apparatus +and its weights are arranged in the interior of the vessel. A man bears +upon the lever, L (Fig. 3), and the counter is set at zero. All being +thus arranged, the man lets go of the break, and the unwinding then +proceeds until the lead has touched bottom. During the operation of +sounding, the boat is kept immovable by means of its engine, so that the +wire shall remain as vertical as possible. The bottom being reached, the +unwinding suddenly ceases, and there is nothing further to do but read +the indication given by the differential counter, this giving the depth. + +[Illustration: FIG. 5.--APPARATUS FOR MEASURING THE LENGTH OF THE WIRE +PAID OUT.] + +Near the winding pulley, there is a small auxiliary engine, M, which +is then geared with the axle of the said pulley, and which raises the +sounding apparatus that has been freed from its weight by a method that +will be described further along. + +We have endeavored in Fig. 4 to show the aspect of the bridge at the +moment when a sounding was about being made. From this engraving (made +from a photograph) our readers may obtain a clear idea of the Thibaudier +sounding apparatus, and understand how the wheel over which the wire +runs is set in motion by the Brothergood engine.--_La Nature_. + + * * * * * + + + + +CABLE GRAPNEL. + + +Some improvements have recently been made by Mr. Alexander Glegg and the +inventor in the well-known Jamieson grapnel used for raising submerged +submarine cables. The chief feature of the grapnel is that the flukes, +being jointed at the socket, bend back against a spring when they catch +a rock, until the grapnel clears the obstruction, but allow the cable +to run home to the crutch between the fluke and base, as shown in the +figures. In the older form the cable was liable to get jammed, and cut +between the fixed toe or fluke and the longer fluke jointed into it. +This is now avoided by embracing the short fluke within the longer one. +The shank, formerly screwed into the boss, is now pushed through and +kept up against the collar of the boss, by the volute spring, which at +the same time presses back the hinged flukes after being displaced by +a rock. The shank can now freely swivel round, whereas before it was +rigidly fixed. The toes or flukes are now made of soft cast steel, which +can be straightened if bent, and the boss is made of cast steel or +gun-metal. + +[Illustration: JAMIESON'S GRAPNEL.] + + * * * * * + + + + +WRETCHED BOILERMAKING. + + +_To the Editor of the Scientific American_: + +As long as I have been a reader of the SCIENTIFIC AMERICAN I have been +pleased with the manner in which you investigate and explain the cause +of any boiler explosion which comes to your knowledge; and I have +rejoiced when you heaped merited censure upon the fraudulent +boilermaker. In your paper in December last you copied a short article +on "Conscience in Boilermaking," in which the writer, after speaking +of the tricks of the boilermaker in using thinner iron for the center +sheets than for the others, and in "upsetting" the edges of the plates +to make them appear thicker, goes on to say: "We call attention to this, +because the discovery of such practice has made serious trouble between +the boilermaker and the steam user. We would not believe that there were +men so blind to the duties and obligations which rest upon them as +to resort to such practice, but the careful inspector finds all such +defects, and in time we come to know whose work is carefully and +honestly done, and whose is open to suspicion. In States and cities +where inspection laws are in force that give the methods and rules by +which the safe working pressure of a boiler is calculated, there is no +alternative except to follow the rules; and if certain requirements +regarding construction are a part of the law, there is no authority or +right to depart from it, and yet there are boilermakers who try to force +their boilers into such localities when their work is not up to the +requirements of the law." + +Now, if some boilermakers are so dishonest as to try and impose upon the +locomotive engineer, who they know will carefully examine every part of +his boiler, and who is able to detect any flaw, it is not to be expected +that the farmer will escape. Nor does he. The great number of explosions +of boilers used in thrashing and in other farm work proves that there +are boilermakers who "force their boilers into such localities +when their work is not up to the requirements of the law." And the +boilermaker, if he be dishonest, is doubly tempted if the broad width of +a continent intervenes between him and the farmer for whom his work is +intended, and if in the place where the boiler is to be used there are +no inspection laws in force. The farmer who lives many miles from a +city, and who has no means of testing any boiler he may purchase, +is wholly at the mercy of the boilermaker, and must run it until it +explodes or time proves it to have been honestly made. Then, again, +there are boilermakers who, although making boilers of good iron and of +the proper thickness, finish them off so badly that the farmer is put to +great inconvenience and expense to put them in working order. Two years +ago I purchased a straw-burning engine and boiler made by an Eastern +firm. Before it had run ten days the boiler began to leak at the +saddle-bolt holes. The engineer tightened the nuts as far as possible, +but could not stop the leaks, which at last became so bad that we had to +stop work and take the engine to the shop. Upon taking off the saddle +and taking out the bolts it was discovered that they were too small for +the holes in the boiler, and that they had been wrapped with candle wick +and white lead to make them fill the holes, and that a light washer had +been put on each bolt between the head and the inside of the boiler. +This washer kept the lead in its place, and prevented the boiler from +showing a leak when first fired up. The water pipes in the fire-box soon +gave out and became utterly useless. Upon inquiring of the patentee of +this straw-burning device, who was supposed to have put it in my boiler, +he stated that he had had nothing to do with it, but that it was put in +by the firm selling these engines, and "as cheaply as possible." Before +I got this boiler and engine in fair running order I had spent hundreds +of dollars and had to do entirely away with the water grates. + +Last summer, needing another tharshing engine, I was induced to buy +one of the same make as my old one, but with a different straw-burning +device. The firm who sold it to me agreed that it should have none of +the faults of the old one. Well, I got it, and, upon hauling it out to +my ranch, and getting up steam, I found it to be much worse than the +first one I had bought. The boiler leaked at nearly every hole where +a tap had been screwed into it. It took an engineer, a boilermaker, a +blacksmith, and a fireman several days to get it in shape so that we +could use it at all; and after we did start up, the boilermaker had +to be sent for several times to stop new leaks that were continually +showing themselves. + +I send you by this mail for your inspection one of the saddle bolts and +one of the bolts taken out of the piston, and also the certificates of +the engineer, boilermaker, and machinist who repaired the boiler. In +justice to my fellow-farmers I ought to publish these certificates and +the names of these boilermakers to the world, but, for the present at +least, I refrain from so doing. These boilermakers will see this article +and they will know, if the public does not, for whom it is intended. If +it has the effect of making them exercise more care in the construction +and fitting up of their engines and boilers, I have not written in vain. + +D. FREEMAN. + +Los Angeles, Cal., March 7,1884. + +[The two bolts and the certificates above referred to accompany the +letter of Mr. Freeman. We can only wonder how it was that, after having +been treated as he relates in the first instance, he should have had any +further business with parties who would send out such boilers, for the +testimony of the engineer and workmen make the case even stronger than +Mr. Freeman has put it.--ED.] + + * * * * * + + + + +A THREADED SET COLLAR. + + +There are cases where a long screw must be rotated with a traversing nut +or other threaded piece traveling on its thread a limited and variable +distance. At one time the threaded nut or piece may be required to +go almost the entire length of the screw, and at another time a much +shorter traverse would be required. In many instances the use of side +check nuts is inconvenient, and in some it is impossible. One way of +utilizing the nut as a set collar is to drill through its side for a set +screw, place it on its screw, pour a little melted Babbitt metal, or +drop a short, cold plug of it into the hole, tap the hole, and the tap +will force the Babbitt into the threads. + +Insert the set screw, and when it acts on the Babbitt metal it will +force it with great friction on to the thread without injuring the +thread; and when the set screw tension is released, the nut turns +freely. A similar and perhaps a better result may be obtained by +slotting the hole through the nut as though for the reception of a key. +Secure a key (preferably of the same material as the nut) by slight +upsetting at its ends, and then thread the nut, key, and all. Place +a set screw through the nut over the threaded key, and the job is +complete. + + * * * * * + + + + +PNEUMATIC MALTING. + + +The lethargy in the malting trade, and in all matters relating to +malting processes, induced by two centuries of restrictive legislation, +is being gradually shaken off by the malting industry under the new law. +For many years nearly all improvements in malting processes originated +abroad, as numberless Acts of Parliament fettered every process and the +use of every implement requisite in a malt-house in this country. The +entire removal of these legislative restrictions gives an opportunity +for improved processes, which promises to open up a considerable +field for engineering work, and to develop a very backward art by the +application of scientific principles. The present time is, therefore, +one of more material change than malting has ever experienced. + +[Illustration: PNEUMATIC MALTING AT TROYES. Fig. 1.] + +Of the numerous improvements effected in the past few years, those made +by M. Galland in France, and more recently by M. Saladin, are by far the +most prominent. M. Galland originated what is known as the pneumatic +system eight or nine years ago. This system is carried out at the +Maxéville brewery, near Nancy. + +[Illustration: PNEUMATIC MALTING AT TROYES. Fig. 2.] + +Since that time further improvements have been made by M. Galland; but +more recently great advances have been made in the system by M. +Saladin. He has developed the practice of the leading principle, and in +conjunction with Mr. H. Stopes, of London, has added improved kilns and +various mechanical apparatus for performing the work previously done by +hand. He has also devised a very ingenious machine for cooling the moist +air by which the process is carried on. + +[Illustration: FIG. 4.--ECHANGEUR AND TURNING MACHINE.] + +At the recent Brewery Exhibition, some of the machinery used in these +new maltings was shown in action by Messrs. H. Stopes & Co., together +with drawings of a malting constructed at Troyes for M. Bonnette under +M. Saladin's instructions. This malting is the third constructed for the +same firm, the others being at Nancy. That at Troyes we now illustrate. +We will not occupy space by a general description of the pneumatic +system, one great feature in which is the continuous manufacture of malt +throughout the year instead of only from five to eight months of the +year, as it will be gathered from the following description of the +Troyes malting: + +[Illustration: FIG. 5.--ECHANGEUR, AXIAL SECTION.] + +In our engravings, Figs. 1, 2, and 3, the letter A indicates the +germinating cases; B, Saladin's patent turning screws; C A, air +channels; D, passages; E R, main driving shafts; e, pulleys; F, metal +recesses to fit turning screws; G, elevators; H, trap doors; I, air +channels; J, openings to growing floor for air; K S, engines and fan +room; L N, fans, supply and exhaust; T, boiler; U, chimney; f, well. The +capacity of the malting is 130 qr. malt every day. This is equivalent to +an English house of 520 qr. steep. The whole space occupied is the area +necessary for kilns, malt and barley stores, engine and boiler house, +and fans. No additional area is required for germinating floors, as ten +germinating cases, A, are placed in the basement below the kilns and +stores. The building is of brick, with the internal walls below the +ground line resting upon cast iron columns and rolled joists. The +germinating cases, A A, are of iron; the bottoms are double. One of +perforated plate is placed 6 inches above the bottom. These plates admit +of draining the corn if the germinating case is used as a steeping +cistern also. Their chief object is, however to admit of ready +circulation of the air by the means presently to be described. Large +channels, A a, serve as drains for moisture and to convey the air to or +from the growing corn. Between each case is a passage, D, enabling the +maltster to have free access to the corn at all points. + +[Illustration: FIG. 6.--ECHANGEUR TRANSVERSE SECTION.] + +With the exception of the driving shaft, E, all the machinery is in +duplicate, so that the possibility is remote of any breakdown that would +seriously affect the working of the house. This is necessary, as should +the fans, L N, be stopped for twenty-four hours the corn germinating +at a depth exceeding 30 inches would heat and impair its vitality. The +boilers, T, and engines, S, are of the common type of 20 horse power +nominal. The fans, L N, are the Farcot patent, illustrated a short time +since in our pages. The lower floors of the kilns are provided with +the Schlemmer patent mechanical turners. The turners, Fig. 4, in the +germinating cases are Saladin's patent. + +[Illustration: FIG. 7.--ECHANGEUR, SECTIONAL PLAN.] + +The germination of the grain is effected by means of cool moist air +provided by the fan described and the cooler and moistener--Figs. 5, 6, +and 7, herewith--known as an _echangeur_. As the germinating grain has +a depth of from 30 inches to 40 inches some pressure is required, and +mechanical means are necessary for efficient and economical turning. +The _echangeur_ is a very ingenious application of the well understood +rapidity of evaporation of any liquid when spread out in very thin +layers over large surfaces and exposed to a current of air. It consists +of a cylinder, or series of cylinders, of increasing diameter, placed +one within another. Each consists of finely perforated sheet iron. They +are placed in a trough of water, just sufficiently immersed to insure +complete wetting. When rotated at a slow speed, the surfaces of all the +cylinders are kept just wetted. A volume of air is either driven or +drawn through, as may be required for any particular purpose. In the +model malting, as shown at Fig. 4, taken from that shown at the Brewery +Exhibition, the air was driven through the _echangeur_ and thence +through the germinating barley. Here or as employed in the malting +illustrated, the air in its passage comes first into contact with the +moistened cylinders, and if hot and dry it becomes moist and cool, for +the constant evaporation upon the cylinders has a very considerable +refrigerating effect. + +This was well known to the Egyptians over four thousand years ago, and +the porous bottle--_gergeleh_--of Esnch has been made until the present +day, to keep the drinking water cool and fresh. The _echangeur_ is +like a gigantic gergeleh, and by increasing the size and number of the +cylinders, and causing the water in the moistening trough to circulate, +any volume of air can be wetted to the saturation limit corresponding to +its temperature. It will be seen that this apparatus gives the maltster +complete control of the humidity and heat as well as volume of the air +driven through germinating corn. + +[Illustration: Fig. 8.] + +The turning apparatus is shown by Fig. 4, and consists, as will be seen, +of a cylindrical frame provided with rollers which run on rails at the +edge of the germinating cases. It is carried to and fro from either end +of the case by compensating rope gearing which at the same time gives +motion to the gearing actuating the turning screws. These screws do not +quite touch the bottom of the germinating case, but are provided with a +pair of small brushes, as shown in the annexed engraving, Fig. 8, which +just skim it. The apparatus shown has but three of these screws, but the +cases are generally made wide enough for six. The kilns are double, +each possessing two floors, and worked upon the Stopes' system. The +construction of the furnaces is of the ordinary French pattern. The +arrangement of the house permits of great regularity in working. Every +day 130 qrs. of barley is screened, sorted, cleaned, and passed into a +steeping cistern. When sufficiently steeped it runs through piping into +the germinating case, which, in the natural order of working, is empty. +Here it forms the couch. When it is desirable to open couch a small +amount of air is forced through the grain by opening the trap door +connected with the main air channel. This furnishes the growing corn +with oxygen, removes the carbonic acid gas, and regulates temperatures +of the mass of grain. Later the Saladin turner is put in motion about +every eight to twelve hours. The screws in rotating upon their axes are +slowly propelled horizontally. They thus effectually turn the grain and +leave it perfectly smooth. This turning prevents matting of the roots, +the regulation of temperature and exposure to air being effected +by means of the cold air from the _echangeur_. When the grain is +sufficiently grown it is elevated to the kilns. For forty hours it +remains upon the top floor. It is then dropped upon the bottom floor, a +further charge of green corn following upon the top floor. The benefit +is mutual. The bottom floor is maintained at an even temperature, being +virtually plunged in an air bath; free radiation of heat is prevented; +the top surface of the malt is necessarily nearly as warm as that next +the wires, which in its turn is subject to lower heats than would be +necessary if free radiation from the surface was allowed. The top floor +is by the intervention of the layer of malt between it and the fire +prevented it from coming into direct contact with heat of a dangerous +and damaging degree. The same heat which is used to dry one floor, and +in an ordinary kiln passes at once into the air as waste, is the best +possible description of heat, namely, very slightly moistened heated +air, to remove the moisture from the second layer of malt at a low +temperature. It is of vital importance to retain this green malt at a +low heat so long as any percentage of moisture exceeding, say, 15 per +cent, is retained by the corn. + +The regulation of temperature is shown by the diagrams, Figs. 9 and 10: + +[Illustration: Fig. 9.] + +[Illustration: Fig. 10.] + +The distribution of the heated air in the kiln is rarely as uniform as +is supposed, the temperature of the malt on drying floor being very +different at different parts. In illustration of this, the following may +be taken from a statement by Mr. Stopes of the results of an examination +of the temperatures at different parts of a drying floor in a kiln in +Norfolk: "A malting steeping 105 qr. every four days has a kiln 75 +feet by 36 feet; an average drying area of under 26 feet per qr. The +consequent depth of green malt when loaded is over 10 inches. The total +area of air inlets is less than 27 feet super. The air outlet exceeds +117 feet, a ratio of 13 to 3. The capacity of head room equals 44,550 +feet cube. The area of each tile is 144 inches, with 546 holes, giving +an effective air area of some 32 inches. The ratio of non-effective +metallic surface to air space is thus 9 to 2." The Casella anemometer +gave no indications at several points, and fluctuating up and down +draughts were observable at many others, especially at two corners and +along the center. "The strongest upward draught pulsated with the gusts +of wind and ranged from 30 feet to 54 feet per minute, a down draught of +equal intensity occurring at intervals at the same spot, notwithstanding +the fact that the air was rushing in at the inlets below the floor at +the high velocity of 785 feet per minute. The temperatures of the drying +malt and superimposed air consequent upon the conditions thus indicated +were naturally as follows: At B, the place supposed to be hottest: Heat +of malt touching tiles, 216 deg.; heat of malt 1 inch above tiles, 167 +deg.; heat of malt 3 inches above tiles 154 deg.; heat of malt 4 inches +above tiles, 152 deg.; heat of malt 5 inches above tiles, 142 deg.; heat +of malt on surface, 112 deg. At A, the place supposed to be coldest: +Heat of malt next tiles, 174 deg.; heat of malt 2 inches above tiles, +143 deg.; heat of malt 4 inches above tiles, 135 deg.; heat of malt on +surface, 104 deg.; the heat of the air 3 feet above tiles, 84 deg.; the +heat of the air 5 feet above tiles, 82 deg. Fig. 9 shows the temperature +at twenty-six points close to the tiles, taken with twelve registered +and accurate thermometers in the space of fifteen minutes." These and +other similar tests have led to the conclusion that the best malt drying +cannot be done on a single floor. + +Fig. 10 is a similar diagram showing the temperatures on a drying floor +of kiln at Poole, Dorset, altered to Stopes' system of drying. The +temperature at different depths of the drying grain was as follows: Malt +at surface of tiles, 142 deg.; malt at 1 inch above tiles, 142 deg.; +malt at 2 inches above tiles, 142 deg.; malt at 4 inches above tiles, +141 deg.; malt on surface, 140 deg. + +The advantages of the Saladin system over that hitherto working in +Britain are numerous, and are thus enumerated by Messrs. Stopes & Co. +who are agents for M. Saladin: The area occupied by the building does +not equal one-third of that otherwise required. The actual growing-floor +space is only about one-seventh, and the number of workmen is ruled +necessarily by the size of the house, but on an average is reduced +two-thirds; but the employment of much more power is necessary, and the +power is used at more frequent intervals. The use of plant and premises +is continuous, the processes of malting being equally well performed +during the summer months. The further advantage of this is that brewers +secure entire uniformity in age of malt. By the English system the +stocks of finished malt necessarily fluctuate largely. All grain is +subjected to the same conditions of surrounding air, exposure, and +temperature. The volume of air supplied to the germinating corn is +entirely under control, as are also its temperature and humidity. When +germination is arrested and the green malt is drying, the double kilns +insure control of the temperatures of the corn in the kilns. The +infrequency of turning the germinating grain benefits the growth of the +roots and the development of the plumule, besides saving much labor. No +grains are crushed or damaged by the feet or shovels of workmen. The air +supplied to the corn can be inexpensively freed from disease germs +and impurities. The capital needed for malting can be reduced by the +diminished cost of installation, and the reduced stocks of malt on hand. +The quality of the malt made is considerably improved. The percentages +of acidity are much reduced. The stability of the beer is increased, +and a greater percentage of the extractive matter of the barley is +obtainable by the brewer.--_The Engineer_. + + * * * * * + + + + +NON-SPARKING KEY. + + +Profs. Ayrton and Perry lately described and exhibited before the +Physical Society their new ammeters and voltmeters, also a non-sparking +key. The well known ammeters and voltmeters of the authors used for +electric light work are now constructed so as to dispense with +a constant, and give the readings in amperes and volts without +calculation. This is effected by constructing the instruments so +that there is a falling off in the controlling magnetic field, and a +considerable increase in the deflecting magnetic field. The deflections +are thus made proportional to the current or E.M.F. measured. The +ingenious device of a core or soft iron pole-piece, adjustable between +the poles of the horseshoe magnet, is used for this purpose. By means of +an ammeter and voltmeter used conjointly, the resistance of part of the +circuit, say a lamp or heated wire, can be got by Ohm's law. Profs. +Ayrton and Perry's non-sparking key is designed to prevent sparking with +large currents. It acts by introducing a series of resistance coils +determined experimentally one after the other in circuit, thereby +cutting off the spark. + + * * * * * + + + + +NEW INSTRUMENTS FOR MEASURING ELECTRIC CURRENTS AND ELECTRO-MOTIVE +FORCE. + +By Messrs. R. E. CROMPTON and GISBERT KAPP. + +[Footnote: Paper read before the Society of Telegraph Engineers, 14th +February, 1884.] + + +In consequence of the rapid development of that part of electrical +science which may be termed "heavy electrical engineering," reliable +measuring instruments specially suitable for the large currents +employed in lighting and transmission of energy have become an absolute +necessity. As usual, demand has stimulated supply, and many ingenious +and useful instruments have been invented, the manufacture of which +forms at the present day an important industry. Mr. Shoolbred, in a +paper which he recently read before this Society, gave a full and +interesting account of the labors of our predecessors in this field. +To-day we add to the list then given a class of instruments invented by +us, examples of which are now before you on the table. We have preferred +to call them current and potential indicators in preference to meters, +considering that the latter term, or rather termination, ought to be +applied rather to integrating instruments, which the necessities of +electric lighting, we believe, will soon bring into extensive use. The +principal aim in the design of these indicators has been to obtain +instruments which will not alter their calibration in consequence of +external disturbing forces. If this object can be attained, then it will +be possible to divide the scale of each instrument directly into amperes +or volts, as the cause may be, and thus avoid the use of a coefficient +of calibration by which the deflection has to be multiplied. This is an +important consideration when it is remembered that in many cases +these instruments have to be used by unskilled workmen, to whom a +multiplication involving the use of demical fractions is a tedious and +in some cases even an impossible task. + +[Illustration: FIG. 1. FIG. 2.] + +All measurements are comparative. We measure weights or forces by +comparison with some generally known and accepted unit standard +weights, lengths, areas, and volumes, by comparison with a unit length, +resistance by a standard ohm, and so forth. In the same way currents +could be measured by comparison with a standard current: but this +would be a troublesome process, not only on account of the apparatus +necessary, but also because it would be a matter of some difficulty to +have a standard current always ready for use. In general, measurement +by direct comparison with a standard unit is discarded for the more +indirect method of measuring not the current itself, but its chemical, +mechanical, or magnetic effect. The chemical method is very accurate if +a proper density of current through the surface of the electrodes be +used,[1] but since it requires a considerable time, and, above all, an +absolutely constant current, its use is almost entirely restricted +to laboratory work and to the calibration of other instruments. For +practical ready use, instruments employing the mechanical or magnetic +effect of the current are alone suitable. We weigh, so to speak, the +current against the force of a magnet, of a spring, or of gravity. +The measurement will be exact if the thing against which we weigh or +counterbalance the current itself retains its original standard value. +Where permanent magnets or springs are used as a balancing force, this +condition of constancy in our weights and measures is not always fully +maintained, and to make matters worse, there is no visible sign by which +a change, should it have occurred, can be readily detected. A spring +may have been overstrained or a steel magnet may have become weakened +without showing the least alteration in outward appearance. To overcome +this difficulty, the obvious remedy is not to use springs or steel +magnets at all, but to substitute for these some other force which +should be either absolutely constant, such as the force of gravity, or +at least should, vary only within narrow limits, and this in accordance +with a definite law. This latter condition can be fulfilled by the +employment of electro-magnets. + +[Footnote 1: According to recent experiments made by Dr. Hammerl, the +density of current in a copper voltameter should be half an ampere per +square inch of surface.] + +[Illustration: FIG 3.] + +To imitate with an electro magnet as nearly as possible a permanent +magnet, so that the former can be used to replace the latter, it is +necessary that the magnetism in the iron core should remain constant. +This could, of course, be done by exciting the electro magnet with a +constant current from a separate source. (In a recent note to the Paris +Academy of Science, M.E. Ducretet described a galvanometer with steel +magnet, which is surrounded by an exciting coil. When recalibration +appears necessary, a known standard current from large Daniell cells is +sent through this coil during a certain time, and thus the magnet is +brought back to its original degree of saturation. M. Ducretet also +mentions the use of a soft iron bar instead of a steel magnet, in which +case the current from the Daniell cells must be kept on during the time +an observation is taken.) But such a system would appear to be too +complicated for ready use. Moreover, some sort of indicator would be +required by which we could make sure that the exciting current has the +normal strength. + +[Illustration: FIG 4.] + +The plan we adopt is to excite the electro magnet by the whole or a part +of the current which is to be measured. Since this current varies, the +power exciting the core of the electro magnet must also vary; and since +we require the core to have as nearly as possible a permanent magnetic +force, we are brought face to face with the question, whether an electro +magnet can be constructed that has a constant moment under varying +exciting currents. This question has been answered by the well known +experiments of Jacobi, Dub, Mueller, Weber, and others. To get an +absolutely constant magnetic moment, is not possible, but between +certain limits we can get a very near approximation to constancy. + +[Illustration] + +The relation between exciting power and magnetic moment is very +complicated, depending not only on the dimensions and shape of the core +and the manner of winding, but also on the chemical constitution of the +iron of the core. It is not possible, or at least it has hitherto not +been found possible, to embody all these various elements into an exact +mathematical formula, which would give the magnetic moment as a function +of the exciting current; but the above mentioned experiments have shown +that within certain limits, and in the neighborhood of the point of +saturation, the relation between the two is that of an arc to its +geometrical tangent. It will be seen that for large angles the arc +increases much slower than the tangent; that is, for strongly excited +cores, a very large increase of the exciting current will produce only +a slight increase of magnetic moment. If Mueller's formula were correct +for all currents, absolute saturation could only be reached with an +infinite current. Whether this be the case or not, it is certain that +the greater the exciting current the less will a variation in it affect +the magnetic moment of the core. To imitate as nearly as possible +permanent steel magnets, it is therefore necessary to use electro +magnets, the cores of which are easily saturated. The core should be +thin and long and of the horseshoe type; the amount of wire wound round +it should be large in comparison with the size of the core. + +[Illustration] + +Here is a magnet partly wound which was used in one of our earliest +experiments, but which was a failure on account of having far too much +mass in the core in comparison with the amount of copper wire wound +round it. Since then we have greatly diminished the iron and increased +the copper. The cores of the instruments on the table are composed of +two or three No. 18 b.w.g. charcoal iron wires, and are wound with one +layer of 0'120 inch wire in the case of the current indicators, and +eighteen layers of 0.0139 inch wire in the case of the potential +indicator. If from the diagram, Fig. 1, we plot a curve the abscissae of +which represent exciting current, and the ordinates magnetic moment of +the soft iron core, we find that a considerable portion of the curve +is almost a straight and only slightly inclined line. If it, were a +horizontal straight line the core would be absolutely saturated, but +such as it is, it answers the purpose sufficiently well, for with a +variation of exciting current from 10 to 100 amperes the magnetic moment +varies but slightly. If a small soft iron or magnetic steel needle, _n +s_, be suspended between the poles, S N, of an electro magnet of such +proportions as described above, and the current, after exciting the +electro magnet, _e e_, be lead round the coils, DD, it will be found +that for all currents between 10 and 100 amperes the needle, _n +s_, shows a definite deflection for each current. Here we have a +galvanometer with permanent calibration. In this case the deflection of +the needle will not strictly follow the law of tangents, because the +directing power of the electro magnet is not absolutely constant; but +whatever the exact ratio between deflection and current may be, it must +always remain the same, and to each angle of deflection corresponds one +definite strength of current. + +[Illustration] + +The force with which the electro magnet tends to keep the needle in its +zero position, that is, in line with the poles, S N, is due partly to +the magnetism of the core, which is nearly constant, and partly to the +magnetic influence of the coils, _ee_, themselves, which is, of course, +simply proportional to the current. The total magnetic force acting on +the needle is, therefore, represented by the sum of these two forces, +and consequently not nearly so constant as might be desired in order to +get a good imitation of a tangent galvanometer with a permanent magnet. +In the diagram, Fig. 2, the curve, O A B, represents the magnetic moment +of the iron core, the straight line, ODE, that of the exciting coils per +se, and the dotted line, O F M, the sum of the two, obtained by adding +for every current, O C, the respective ordinates, CD and C A. + + CF = CD + CA + +The rise of this curve shows that the force which tends to bring the +needle back to its zero position increases with the current, though at a +slower ratio than the deflecting force of the current. It follows from +this that for large currents the increment in the angle of deflection is +comparatively small, and the divisions on the scale whereon the current +is to be read off would come too near together to allow accurate +readings to be taken. In other words, the range of accurate reading in +an instrument so constructed would only be limited. But it is very easy +to eliminate the magnetic effect of the coils of the electro magnet on +the needle, by introducing an opposite magnetic effect, so that only +that part of the force remains which belongs to the soft iron core +proper. One way of doing this is by surrounding the needle with a coil, +the plane of which is at right angles to the line, S N, and coupling +this coil in series with the deflecting coil, D D. If the proportions +of this transverse coil and the direction of the current through it +be properly chosen, its magnetic effect can be made to exactly +counterbalance that of the exciting coils, _e e_, without perceptibly +weakening the magnetism of the iron core. But instead of employing two +coils, one parallel and the other transversely to the zero position of +the needle, we can obtain the same result in a more simple manner with +one coil only, if this be placed at such an angle that its magnetic +effect can be substituted for the combined effects of the two coils. In +other words, we set the deflecting coil, D D, at a certain angle to the +zero position of the needle. + +A similar arrangement, though not precisely for the same purpose, has +already been suggested and tried by Messrs. Deprez, Carpentier, Ayrton, +and Perry, in galvanometers with permanent steel magnets. If the coil, +D D, be so placed, the deflecting force which now acts obliquely can be +considered as the resultant of two forces, one acting at right angles to +the line, S N, as in an ordinary galvanometer, and the other parallel to +this line, but in a sense opposed to the action of the electro magnet +and its exciting coils. If the angle of obliquity be so chosen that this +latter component exactly equals the magnetic effect of the exciting +coils _per se_, an equality which holds good for all currents, then we +shall have an almost perfect imitation of a tangent galvanometer with +permanent magnets. But we can go a step further than this; we can +overbalance the exciting coils by setting the deflecting coil at a +greater angle than necessary for the mere elimination of the former, and +thus attain that an increase of current results in a slight weakening of +the field in which the needle swings, thus allowing the increment of the +angle of deflection to be comparatively large even for large currents. +In this way it is possible to obtain a more evenly divided scale than +in the case when the deflection follows the law of tangents, as in an +ordinary tangent galvanometer. This principle of overbalancing the +exciting coils is shown on diagram, Fig. 2. The straight line, O G, +represents the magnetic effect on the needle of that component of the +deflecting force which is parallel, but in sense opposed to S N; +as mentioned above, the magnetic effect of the exciting coils is +represented by the straight line, O E. The combined effect of these two +forces on the needle is represented by the line, O K, the ordinates +of which must be deducted from those of the curve, O A B, in order to +obtain the total directing force due to each current. This is shown by +the curve, O P Q, shown in a thick full line. This curve shows how +the directing force or strength of field in which the needle swings +decreases with an increasing current. That this does actually take place +can easily be proved by experiment. + +Fig. 4 shows two curves; the one drawn in a full line is obtained +by plotting the deflection in degrees of the needle of a potential +indicator as abscissae, and the corresponding electromotive forces +measured simultaneously on a standard instrument as ordinates; the +dotted line shows what this curve would be with an ordinary tangent +galvanometer. + +The needle of the potential indicator is mounted at the lower end of +a steel axle, to the upper end of which is fastened a light aluminum +pointer, whereby the deflection of the needle can be read off on a scale +divided directly into volts. The scale is placed within a circular dial +plate with glass cover, giving sufficient room for the pointer to swing +all round, and the needle is placed within a central tube fitting it +closely, which acts as a damper and so makes the instrument almost +dead beat. Tube and dial are in one casting. The electro magnet is of +horseshoe form fastened to a central tubular stand, which also serves +to support the two deflecting coils, one on either side of it. The tube +within which the magnetic needle swings is inserted into the stand, +which is bored out to the external diameter of the tube. The electro +magnet and deflecting coils are wound with from 50 to 100 ohms of fine +insulated copper wire, and an additional resistance coil of from 450 +to 900 ohms of German silver is added, which can, however, be short +circuited by depressing a key when the instrument has to be used for +reading low electromotive forces. In this case the indication of the +pointer must be divided by ten. If a current be sent through the +instrument the wrong way, the needle turns through an angle of 180°, and +thus brings the pointer to the side of the dial opposite to where the +scale is. In this position no reading can be taken, and to facilitate +the sending of the current in the right direction a commutator is added, +and the same is so coupled up that when the pointer stands over the +scale the handle on the commutator points to the positive terminal +screw. There is a limit of electromotive force below which the indicator +fails to give reliable readings. For instance, an instrument wound with +100 ohms of copper wire and 900 ohms of German silver can be used for +electromotive forces varying between 300 and 3 volts, but would not be +reliable for measuring less than 3 volts. + +For very exact measurements the instrument should be placed north and +south, in the same position in which it was calibrated. Two different +patterns of current indicators are on the table; one with double needles +suspended on a point in the way compass magnets are suspended, the other +with one lozenge shaped needle mounted on an axle and pivoted on jewels, +in every way similar to the needle of the potential indicator first +described. + +For measurements of currents from 10 amperes upward, there is no need +to employ a complete coil as the deflecting agent; one half-coil or one +strip passing close under the needle gives sufficient deflecting force, +and thus the construction of the instrument is rendered extremely +simple. The current, after entering at one of the flat electrodes, +splits in two parts, each part passing round the winding of an electro +magnet of horseshoe form, the similar poles of both magnets pointing +toward each other and toward the needle. After traversing the winding, +the current unites again, and passes through a metal strip close under +the needle, and finally out of the instrument by the other electrode, +which lies close under that at which the current entered, but is +insulated from it by a sheet of fiber. The metal strip is set at an +angle, to balance or overbalance, as may be preferred, the magnetic +influence of the exciting coils. The effect of this overbalancing is +shown in Fig. 5, where the full curve represents the current as a +function of the deflection--obtained by comparison with a standard +instrument--and the dotted curve shows what that relation between +deflection and current would be if the law of tangents held good for +these instruments. It will be seen that, about the middle of the scale, +the dotted line coincides nearly with the full line, while at the +extreme end of the scale the dotted line is higher. From this follows, +that if we compare our indicator from which this curve was taken with +any form of tangent instrument showing an equal angle of deflection at +the medium reading, it will be seen that the needle of our indicator +will be deflected to a greater angle at high readings than that of the +tangent galvanometer. Consequently, the divisions on the scale will +be widest apart in our instruments, which greatly facilitates high +readings. + + * * * * * + + + + +SECONDARY BATTERIES. + + +The Consolidated Electric Light Company has now completed the secondary +battery which has for some time engaged the attention of its officers, +and their regular manufacture and use for electric lighting stations +have been fairly entered upon. Among other places to which the batteries +have been sent and put into work is Colchester, where the company +has for some time had an installation at work, chiefly employing +incandescent lamps. The battery consists of lead electrodes, anode and +cathode being of the same character. They are constructed of narrow +ribbons of lead, each element being made from long lengths of the ribbon +about or nearly 0.20 in. width, rolled together into a flat cake like +rolls of narrow webbing, as illustrated by the annexed diagram, Fig. +1, the greater part of the ribbon being very thin and flat; but +intermediate thicker ribbons are also employed, as in Fig. 2, this +thicker ribbon being corrugated as shown, and affording passage room +for the circulation of the electrolyte. From four to eight coils of the +plain ribbons are between every pair of corrugated ribbons. They are +wound up together tightly, and pressed into the nearly rectangular form +shown. The bar for suspending the coil plates so made in the cells is +soldered to the coil. The object of this construction is of course to +obtain large lead surface, and of course a much larger surface is so +obtained than could be practically obtained from plain lead plates in +the same compass. A battery thus made may be seen at the offices of the +company, 110 Cannon Street. + +[Illustration: FIG. 1. FIG. 2.] + +A very ingenious device for cutting the battery out of circuit when +charged as much as is thought desirable is used by the company. In a +cell is an element which has a determined lower capacity than those in +the rest of the battery. Over this element is placed a gas-tight chamber +in which is a diaphgram, this diaphragm being of very flexible material +placed in the cover of the box of cells. When charging has proceeded as +long as is desirable, or proceeds too fast, hydrogen is evolved, and +this collecting in the chamber referred to acts upon the diaphragm, and +by means of a rod connected thereto, switches the current, which is +supplied to an electro-magnet and by which circuit is made through the +medium of mercury contacts. The object, of this is to save the +battery from destruction by over-charging or charging by too large a +current.--_The Engineer_. + + * * * * * + + + + +ACETYLENE FROM IODOFORM. + + +P. CAZENEUVE publishes in the _Comptes Rendus_ a new method for the +preparation of acetylene, which consists in mixing iodoform intimately +with moist and finely divided silver. An abundant evolution of acetylene +takes place without heating. The reaction is represented by the +following formula: 2CHI_{3} + 6Ag = C_{2}H_{2} + 6 AgI. The +decomposition of the iodoform is hastened if the silver is mixed with +finely divided copper, such as can be obtained by precipitating it from +its sulphate by means of zinc. + +Cazeneuve also observed that most metals which have any affinity for +iodine will decompose iodoform in the presence of water, forming +acetylene and an iodide of the metal. By the use of zinc he obtained a +liquid having a pleasant ethereal odor, and a gas mixture that contained +besides acetylene an iodine compound which burned with a purple-edged, +fawn-colored flame. + + * * * * * + + + + +WHEN DOES AN ELECTRICAL SHOCK BECOME FATAL? + + +In this age of electricity and electric wires carrying currents of +various intensity, the question of danger arising from contact with them +has caused considerable discussion. An examination into the facts as +they exist may therefore enlighten some who are at present in the dark. + +To begin with, we often hear the question asked--why is it that certain +wires carrying very large currents give very little shock, whereas +others, with very small currents, may prove fatal to those coming in +contact with them? The answer to this is--that the shock a person +experiences does not depend upon the current _flowing in the wires_, but +upon the current _diverted from them_ and _flowing through the body_. + +The muscular contraction due to a galvanic current, which was first +observed in the frog, gives a good illustration of the fact that it +requires only a very minute current to flow through the muscles in order +to contract them. Thus the simple contact of pieces of zinc and copper +with the nerves generated current sufficient to excite the muscles--a +current which would require a delicate galvanometer for its detection. +What is true of the muscles of the frog holds good also for the human +muscles; they too are very susceptible to the passage of a current. + +In order to determine the current which proves fatal we need only to +apply the formula which expresses Ohm's law, viz., C=E/R, or the current +(ampere) equals the electromotive force (volt) divided by the resistance +(ohm). + +According to the committee of Parliament investigation, the +electromotive force dangerous to life is about 300 volts; this then is +the quantity, E, in the formula. There remains now only to determine the +resistance in ohms which the body offers to the passage of the current. +In order to obtain this, a series of measurements under different +conditions were made. On account of the nature of the experiment a high +resistance Thomson reflecting galvanometer was used, with the following +results. + +When the hands had been wiped perfectly dry, the resistance of the body +was about 30,000 ohms; with the hands perspiring ordinarily it fell to +10,000 ohms; whereas when they were dripping wet it was as low as 7,000 +ohms. Our readers can judge this resistance best when we state that the +Atlantic cable offers a resistance of 8,000 ohms. + +Taking an ordinary condition of the body, with the hands perspiring as +usual, we would have the resistance equal to 10,000 ohms. Applying the +two known quantities in the formula, we get: + + C = (300 / 10,000) - (1 / 33.333+) + +This means, therefore, that when the electromotive force or potential is +great enough to send a current of 1/33 ampere through the body, fatal +results will ensue. This current is so minute that it would deposit only +about 6 _grains_ of copper in _one hour_, a grain being 1/7,000 of a +pound. + +Let us now compare these figures with some actual cases, taking as +an example a system of incandescent lighting. In these systems the +difference of potential between any two points of the circuit outside of +the lamps does not exceed 150 volts. Taking this figure, therefore, it +will be seen that under no circumstances can the shock received from +touching these wires become dangerous--not even by touching the +terminals of the dynamo itself; because in neither case can a current be +driven through the body, sufficient to cause an excessive contraction of +the muscles. + +In a system of arc lighting, however, we have to deal with entirely +different conditions; for, while in the incandescent system the adding +of a lamp, which diminishes the resistance, requires no increase of +electromotive force, the contrary is the case in the arc light system. +Here every additional lamp added to the circuit means an increase in +resistance, and consequent increase in electromotive force or potential. +Taking for example a well known system of arc lighting, we find that the +lamps require individually an electromotive force of 40 volts with a +current of 10 amperes. In other words, the difference in potential at +the two terminals of every such lamp is 40 volts. Consequently, if the +circuit were touched in two places, including between them only one +lamp, no injurious effects would ensue. If we touch the circuit so as +to include two lamps between us, the effect would be greater, since the +potential between those two points is 2 x 40 volts. We might continue +in this manner touching the circuit until we had included about 7 or +8 lamps, when the shock would become fatal, since the point would be +reached at which the difference of potential is great enough to send a +dangerous current through the body. + +Up to this point we have assumed that, while touching two points in the +wire, the rest of the circuit is perfectly insulated, so that no current +can leak, in other words, that the circuit is nowhere "grounded." If +this is not the case we may, under suitable conditions, receive a +shock by touching only _one_ point of the wire. This becomes clear +by considering the current to leak from another spot of different +potential, to pass through the ground and into the body; thus, on +touching the wire the body virtually makes a connection between the +two points of the circuit. In clear dry weather such leaks are +insignificant; but in damp and rainy weather, and with poor insulation, +they may rise to such a point at which it would be dangerous to touch +the circuit even with one hand, the leaks being sometimes so great as +to cause the lamps to burn in a fitful, desultory manner, and to go out +entirely. + +There is still another factor which enters into the discussion of the +danger of electric light wires. This must be looked for in the fact that +the physiological effects are greatest at the moment of the opening or +the closing of the circuit; or in a closed circuit they are the more +marked when the flow of current stops and starts, or diminishes and +increases. In dynamo electric machines the current is not absolutely +continuous or uniform, since the coils on the armature being separated a +distance cause a slight break or diminution of the current between each. +This break is so short that it does not interfere with the practical +work for lighting; in some constructions, nevertheless, the distances +apart is so great that, while not interfering with light, its effects +upon the muscles are greatly increased over those of other constructions +which give a more uniform current. + +All these statements might lead to the conclusion that arc light wires +are dangerous under any circumstances; but this is not the case. The +first and only requisite is, that they be perfectly insulated. When thus +protected accidents from them are impossible, and all mishaps that have +occurred through them can be traced directly to the lack of insulation. +Nevertheless, we would warn our readers against experimenting upon arc +wires by actual trial, because unforeseen conditions might lead to +disagreeable results. + + * * * * * + + + + +ROBERT CAUER'S STATUE OF LORELEI. + + +The statue of Lorelei, the mythical siren of the Rhine, represented in +the annexed cut, which is taken from the _Illustrirte Zeitung_, was +modeled by Robert Cauer, of Kreuglach on the Rhine. He was born at +Dresden in 1831, and is the son of the well-known sculptor Emil Cauer, +and a brother of the sculptor Karl Cauer. + +[Illustration: LORELEI STATUE BY ROBERT CAUER.] + + * * * * * + + + + +REDUCING AND ENLARGING PLASTER CASTS. + + +Ordinary casts taken in plaster vary somewhat, owing to the shrinkage of +the plaster; but it has hitherto not been possible to regulate this +so as to produce any desired change and yet preserve the proportions. +Hoeger, of Gmuend, has, however, recently devised an ingenious method +for making copies in any material, either reduced or enlarged, without +distortion. + +The original is first surrounded with a case or frame of sheet metal or +other suitable material, and a negative cast is taken with some elastic +material, if there are undercuts; the inventor uses agar-agar. The usual +negative or mould having been obtained as usual, he prepares a gelatine +mass resembling the hektograph mass, by soaking the gelatine first, then +melting it and adding enough of any inorganic powdered substance to give +it some stability. This is poured into the mould, which is previously +moistened with glycerine to prevent adhesion. When cold, the gelatine +cast is taken from the mould, and is, of course, the same size as the +original. If the copy is to be reduced, this gelatine cast is put in +strong alcohol and left entirely covered with it. It then begins to +shrink and contract with the greatest uniformity. When the desired +reduction has taken place, the cast is removed from its bath. From +this reduced copy a cast is taken as usual. As there is a limit to the +shrinkage of the gelatine cast, when a considerable reduction is desired +the operation is repeated by making a plaster mould from the reduced +copy, and from this a second gelatine cast is taken and likewise +immersed in alcohol and shrunk. It is claimed that even when repeated +there is no sacrifice of the sharpness of the original. + +When the copy is to be enlarged instead of reduced, the gelatine cast is +put in a cold water bath, instead of alcohol. After it has swollen as +much as it will, the plaster mould is made as before. For enlarging, +the mould could also be made of some slightly soluble mass, and then by +filling it with water the cavity would grow larger, but it would not +give so sharp a copy. + + * * * * * + + + + +STRIPPING THE FILM FROM GELATINE NEGATIVES. + + +We have frequent inquiries as to the best means of removing a +gelatino-bromide negative from its glass support so that it can be used +either as a direct or reversed negative, and it does not appear to be +very generally known that about two years ago Mr. Plener described a +method which answers well under all circumstances, whether a substratum +has been used or not. + +If a negative is immersed in extremely dilute hydrofluoric acid +contained in an ebonite dish, say half a teaspoonful to half a pint of +water, the film very soon becomes loosened, and floats off the glass, +this circumstance being due to the solvent action which the acid +exercises upon the surface of the plate as soon as it has penetrated the +film. If the floating film be now caught upon a plate which has been +slightly waxed, and it is allowed to dry on this plate, it will become +quite flat and free from wrinkles. To wax the plate, it should be held +before the fire until it is moderately hot, after which it is rubbed +over with a lump of wax, and the excess is polished off with a piece +of flannel. When the film is dry, it will leave the waxed glass +immediately, if one corner is lifted by means of a penknife. The film +will become somewhat enlarged during the above-described operation; but, +by taking suitable precautions, this enlargement may be avoided. It is +also convenient to prepare the hydrofluoric acid extemporaneously by the +action of sulphuric acid on fluoride of sodium; and, in many cases, it +is advisable to thicken up the film by an additional layer of gelatine. + +The following directions embody these points. The negative, which must +be unvarnished, is leveled, and covered with a layer of warm gelatine +solution (one in eight) about as thick as a sixpence. This done, and +the gelatine set, the plate is immersed in alcohol for a few minutes +in order to remove the greater part of the water from the gelatinous +stratum. The next step is to allow the plate to remain for five or six +minutes in a cold mixture of one part of sulphuric acid with twelve +parts of water, and in the mean time two parts of sodium fluoride are +dissolved in one hundred parts of water, an ebonite tray being used. A +volume of the dilute sulphuric acid equal to about one-fourth of the +fluoride solution is next added from the first dish, and the plate +is then transferred to the second dish, when the film soon becomes +liberated. When this is the case, it is placed once more in the dilute +sulphuric acid. After a few seconds it is rinsed in water, and laid on a +sheet of waxed glass, complete contact being established by means of a +squeegee, and the edges are clamped down by means of strips of wood held +in position by American clips or string. All excess of sulphuric acid +may now be removed by soaking the plate in methylated alcohol, after +which it is dried. It is as well to add a few drops of ammonia to the +last quantity of alcohol used. + +The plate bearing the film negative is now placed in a warm locality, +under which circumstances a few hours will suffice for the complete +drying of the pellicular negative, after which it may be detached +with the greatest ease by lifting the edges with the point of a +penknife.--_Photo. News_. + + * * * * * + + + + +NEW ANALOGY BETWEEN SOLIDS, LIQUIDS, AND GASES, + +By W. SPRING. + + +The author asks in the first place, What is the cause of the different +specific gravities of one and the same metal according as it has been +cast, rolled, drawn into wire, or hammered? Does the difference observed +prove a real condensation of the matter under the action of pressure, or +is it merely due to the expulsion by pressure of gases which have been +occluded when the ingot was cast? According to well-known researches, +metals such as platinum, gold, silver, and copper, which have +been proved to occlude gases on fusion, and to let them escape, +_incompletely_, on solidification, are precisely those which are +most increased in their specific gravity by pressure. The author has +submitted to pressures of about 20,000 atmospheres metals which possess +this property, either not at all, or to a very trifling extent, and he +finds that though a first pressure produces a slight permanent increase +of density, its repetition makes little difference. Their density is +found to have reached a maximum. Hence the density of solids, like that +of liquids, is only really modified by temperature. Pressure effects +no permanent condensation of solid bodies, except they are capable of +assuming an allotropic condition of greater density. The author's former +researches tend to show that solid matter, in suitable conditions of +temperature, takes the state corresponding to the volume which it is +compelled to occupy. Hence there is an analogy between the allotropic +states of certain solids and the different states of aggregation of +matter. Possibly the different forms of matter may be due to a single +cause--polymerization. The limit of elasticity of a solid body is the +critical moment when the matter begins to flow under the action of the +pressure to which it is submitted, just as, e.g., ice at or below 0° may +be liquefied by strong pressure. A brittle body is simply one which does +not possess the property of flowing under the action of pressure. + + * * * * * + + + + +HYDROGEN AMALGAM. + + +Hydrogen, although a gas, is recognized by chemists as a metal, and when +combined with any solid metal--as in the case known to electricians as +the polarization of a negative element,--the compound may correctly be +termed an alloy; while any compound of hydrogen with the fluid metal +mercury may with equal correctness be termed an amalgam of hydrogen, or +"hydrogen amalgam." The efforts of many chemists and mining engineers +have for many years been devoted to a search for some effective and +economical means for preventing the "sickening" of mercury and its +consequent "flouring" and loss. Some sixteen or more years ago, +Professor Crookes, F.R.S., discovered and, after a series of +experiments, patented the use of an amalgam of the metal sodium for this +purpose. He made the amalgam in a concentrated form, and it was added +in various proportions to the mercury used for gold amalgamation. Water +becoming present, it will readily be understood that the sodium, in +being converted into the hydrate (KHO) of that metal, caused a rapid +evolution of hydrogen. The hydrogen thus evolved was the excess over a +certain proportion which enters into combination with the mercury. While +the mercury retained the charge of hydrogen, the "quickness" of the +fluid metal was preserved; but upon the loss of the hydrogen the +"quickness" ceased, and the mercury was acted upon by the injurious +components contained in the ore. + +Since the introduction of the sodium amalgam, many attempts have been +made, more especially in America, to overcome the tendency of mercury to +"sicken" and lose its "quickness." The greater number of these efforts +have been made by the use of electricity as the active agent in +attaining this end; but such efforts have been generally of a crude and +unscientific character. Latterly Mr. Barker, of the Electro-amalgamator +Company, Limited, has introduced a system--already detailed in these +pages--by which the mercury is "quickened." In his method the running +water passing over the tables, or other apparatus of a similar +character, is used as the electrolyte. In this arrangement, the mercury +being the cathode, plates or wires of copper constituting anodes are +brought into contact with the water passing over the mercury in each +"riffle." Both the cathode and the anodes are, of course, maintained in +contact with the poles of a suitable source of electrical supply. The +current then passes from the copper anode through the running water +to the mercury cathode, and so on to the negative pole of the +electro-motor. As a consequence of this arrangement, hydrogen is evolved +from the water, and has the effect of reducing any oxide or other +detrimental compound of the metal; in other words, it "quickens" and +prevents "sickening" of the fluid metal, and consequent "flouring" and +loss. While the hydrogen is evolved at the cathode, oxygen enters into +combination with the copper constituting the anodes. This to some extent +impairs the conductivity of the circuit. + +The latest process, however, is that of Mr. Bernard C. Molloy, M.P., +which we have already characterized as highly scientific and effective, +the production of a suitable amalgam being obtained under the most +economical and simple conditions. This process has the advantage of +producing not only a hydrogen amalgam, but also at will an amalgam of +hydrogen combined with any metal electro-positive to this latter. Thus +hydrogen potassium or hydrogen sodium can be obtained, as will be seen +by the following description. + +Mr. Molloy's effort appears to have been, in the first place, directed +to a system which could be adapted to any existing apparatus, and in +certain cases where water was scarce, to avoid altogether the use of +that, in some districts, rare commodity. For the purpose of explanation +we select an ordinary amalgamating table fitted with mercury riffles. +The surface of the table is in no way interfered with or disturbed. The +bed of the riffle, however, is constructed of some porous material, such +as leather, non-resinous wood, or cement, which serves as the diaphragm +upon which the mercury rests, and separates the fluid metal from the +electrolyte beneath. Running the full length of the table is a thin +layer of sand, supported and pressing against the diaphragm, and lying +in this sand is the anode, formed preferably of lead. A peroxide of +that metal is formed by the action of the currents, and may be readily +reduced for use over and over again after working for from one to three +months. The peroxide of lead, as is well known, is a conductor of +electricity, and this fact constitutes an important advantage in the +working of the process. The thin layer of sand is saturated with an +electrolyte, such as dilute sulphuric acid (H_{2}SO_{4} + 20H_{2}O) +to give a simple hydrogen amalgam; (Na_{2}SO_{4} + xH_{2}O) to give a +hydrogen sodium amalgam; or (K_{2}SO_{4} + xH_{2}O) to give a hydrogen +potassium amalgam. Numerous other electrolytes constituted by acids, +alkalies, and salts can be used to form an amalgam permanently +maintained in a condition of "quickness" and freed from all liability +to "sicken," whatever the components of the ore may be. The mercury +is connected with the negative pole of the voltaic battery or other +electro-motor, and the lead made with the positive pole of the same +source. When the current passes there is formed according to the nature +of the electrolyte, a hydrogen amalgam, or an amalgam of hydrogen with a +metal electro-positive to hydrogen. The electrolyte, which, it will be +understood, is distinct and apart from the body of water passing over +the table, will last almost indefinitely, there being no consumption of +any of its constituents, excepting hydrogen and oxygen from the water +of solution. The quantity of acid or saline material contained in the +electrolyte is so very small that there can be no difficulty in finding +a supply in any district. The question of the supply of electricity is +one which in many mining districts involves considerations of practical +importance, since a large supply would necessitate water or steam power. +It has been found that two cells having an electromotive force of about +two volts each will in this process suffice; if preferred, however, +a very small dynamo machine can be used. In connection with the +electro-motive force it is requisite to use, it may be observed that an +amalgam of sodium containing only a small quantity of this metal would, +when constituting a positive element in conjunction with a lead negative +and on an aqueous electrolyte, give an opposing electro-motive force of +less than three volts. Such an amalgam could therefore be obtained under +an electro-motive force of about four volts. The electrical resistance +in the circuit constituted by the apparatus being very small, no +electrical power is wasted. When water constitutes the electrolyte, as +in Barker's system, then the electro-motive force required to obtain a +given current would be very much greater than that above specified. +The conditions assured under this process appear to be all that can +be required, while the amalgams obtained are those most calculated to +preserve the "quickness" and prevent the "sickening" of the mercury. + +Mr. Molloy has designed a special form of amalgamating machine to be +used in conjunction with the above process, and with or without the aid +of water. By the employment of this machine, each particle of the ore +is slowly rolled in the quickened mercury for from fifteen to thirty or +more seconds. + +When the extent of the gold and silver mining industries is considered, +and when it is borne in mind that a considerable percentage of the +precious metal present in the ore is, in the ordinary process of +extraction, lost through defective amalgamation--due to insufficient +contact with the mercury or to a total absence of contact, as in the +case of float gold--it is obvious that the introduction of any system +obviating such loss is a matter of very great importance to those who +are interested in the above mentioned industries. We expect shortly to +hear of the practical introduction on a large scale of Mr. Molloy's +process, and we look forward with interest to the results which may be +obtained from it.--_The Engineer_. + + * * * * * + + + + +TREATMENT OF ORES BY ELECTROLYSIS. + +By M. KILIANI. + + +The author lays down general principles for electrolytic metallurgy. +Ores must be distinguished as good and bad conductors; the former +may serve directly as anodes, and are easily oxidized by the +electro-negative radicals formed at their contact, and dissolve readily +in the electrolyte. The bad conductors have to be placed in contact +with a conducting anode, formed of an inoxidizable substance, such as +platinum, manganese peroxide, or coke. In laboratory experiments a good +conducting ore is electrolyzed by suspension from a platinum wire in +connection with the source of electricity, and is then immersed in the +bath. On an industrial scale the ore, coarsely broken up, is placed in +one of the compartments of a trough divided by a diaphragm. + +On the fragments of the ore which extend up outside of the electrolytic +bath is laid a plate of copper connected with the positive wire. Care +must be taken that this plate does not plunge into the bath, otherwise +the current would not traverse the ore at all. The cathode is preferably +formed of the same metal which is to be obtained. The bath should +not contain organic acids. In practice the common mineral acids are +employed, or their salts, selecting by preference a salt of the metal +which is to be isolated. It is convenient to pass the current through +the greatest possible number of small decomposition troughs, taking care +that the resistance in each is not too great. With a current of one and +the same intensity we obtain in n troughs n times as much metal as in a +single one. To keep down the resistance of the circuit we employ poles +of a large surface, i.e., plenty of ore and baths which are as good +conductors as possible. + +The state in which the metal is deposited at the negative pole depends +on the secondary actions undergone by the electrolyte, and especially of +the escape of gas. This is a function of the _density_, of the current, +i.e., the proportion of its intensity to the surface of the cathode. If +the density is too great there is an escape of hydrogen, and the metal +is deposited in a spongy condition. If the density of the current falls +below a certain minimum, an oxide is deposited in place of metal. The +electrolytic treatment of ores often renders it possible to separate +the different metals which may be present. These are deposited in +succession, and are sharply separated if the electromotive power is not +too great. + +1. _Zinc_.--The zinciferous compounds--calamine, blende, and zinc +ash--are all poor conductors. They are first dissolved, and the salts +obtained are electrolyzed, employing anodes of coke. Blende should be +roasted before it is dissolved. The electrolytic bath should be as +concentrated as possible to avoid sponginess of the metal and an escape +of hydrogen. In a saturated solution the formation of hydrogen decreases +as the density of the current augments. + +2. _Lead_.--Galena is a good conductor, and may be directly +electrolyzed. The best bath is a solution of lead nitrate. The +arborescent crystallizations extend rapidly, and must be broken from +time to time to prevent the formation of a metallic connection between +the anode and the cathode. The sulphur of the galena falls to the bottom +of the bath, and may be separated from the gangue by solution in carbon +disulphide. + +3. _Copper_.--Native copper sulphide, though a good conductor, cannot +be directly electrolyzed en account of the presence of iron sulphide, +whence iron would be deposited along with the copper. The copper pyrites +are roasted, dissolved in dilute sulphuric acid, and the liquid thus +obtained is submitted to electrolysis. + + * * * * * + + + + +A PEOPLE WITHOUT CONSUMPTION, AND SOME ACCOUNT OF THEIR COUNTRY--THE +CUMBERLAND TABLELAND. + +By E. M. WIGHT, M.D., Chattanooga, Tenn., Late Professor of Diseases +of the Chest and State Medicine, Medical Department University of +Tennessee; Late Member of the Tennessee State Board of Health, and +ex-President of the Tennessee State Medical Society. + + +During the ten years that I have practiced medicine in the neighborhood +of the Cumberland Tablelands, I have often heard it said that the +people on the mountains never had consumption. Occasionally a traveling +newspaper correspondent from the North found his way down through the +Cumberlands, and wrote back filled with admiration for their grandeur, +their climate, their healthfulness, and almost invariably stated that +consumption was never known upon these mountains, excepting brought +there by some person foreign to the soil, who, if he came soon enough, +usually recovered. Similar information came to me in such a variety of +ways and number of instances, that I determined some four years ago, +when the attempt to get a State Board of Health organized was first +discussed by a few medical men of our State, that I would make an +investigation of this matter. These observations have extended over that +whole time, and have been made with great care and as much accuracy +as possible, and to my own astonishment and delight, I have become +convinced that pulmonary consumption does not exist among the people +native and resident to the Tablelands of the Cumberland Mountains. + +In the performance of the work which has enabled me to arrive at this +conclusion, I have had the generous assistance of more than twenty +physicians, who have been many years in practice in the vicinity of +these mountains. Their knowledge of the diseases which had occurred +there extended over a, period of more than forty years. Some of these +physicians have reported the knowledge of the occurrence of deaths from +consumption on the Tablelands, but when carefully inquired into they +have invariably found that the person dying was not a native of the +mountains, but, a sojourner in search of health. In answer to the +question: "How many cases of pulmonary consumption have you known to +occur on Walden's Ridge, among the people native to the mountains?" +eleven physicians say, "Not one." All of these have been engaged in +practice there more than three years, four of them more than ten years, +one of them more than twenty, and one of them more than forty years. All +the physicians of whom inquiries have been made are now residents, or +have been, of the valleys contiguous to Walden's Ridge, and know the +mountain people well. Four other physicians in answer to the same +question say, that they have known from one to four cases, numbering +eleven in all, but had not ascertained whether five of them were born +and raised on the mountains or not. The names and place of death of all +these cases were given, and I have traced their history and found that +but three of them were "natives," or had lived there more than five +years, and that one of these was 57 years of age when she died, and had +suffered from cancer for three years before her death. The two others +died within six months after returning home from long service in the +army, where both contracted their disease. + +All these investigations have been made with more particular reference +to that part of the Cumberlands known as Walden's Ridge than to the +mountains as a whole. This ridge is of equal elevation and of very +similar character to the main Cumberland range in the southern part of +Tennessee, northwest Georgia, and northwest Alabama, and what is true of +this particular part of the great Cumberland table is, in the main, true +of the remainder. + +Sequatchee Valley lies between Walden's Ridge and what is commonly known +in that neighborhood as the Cumberland Mountains, and separates it from +the main range for a distance of about one hundred miles, from the +Tennessee River below Chattanooga to Grassy Cove, well up toward the +center line of the State. Grassy Cove is a small basin valley, which +was described to me there as a "sag in the mountains," just above the +Sequatchee Valley proper. It is here that the Sequatchee River rises, +and flowing under the belt of hills which unites the ridge and the main +range, for two miles or more, rises again at the head of Sequatchee +Valley. Above Grassy Cove the mountains unite and hold their union +firmly on their way north as far as our State reaches. + +Topographically considered as a whole, the Cumberland range has its +southern terminus in Alabama, and its northern in Pennsylvania. It +is almost wholly composed of coal-bearing rocks, resting on Devonian +strata, which are visible in many places in the valleys. + +But a small portion of the Cumberland lies above a plane of 2,000 feet. +Walden's Ridge and Lookout Mountain vary in height from 2,000 to 2,500 +feet. + +North of Grassy Cove, after the ridges are united, the variation from +2,000 feet is but little throughout the remainder of the State, and +the general character of the table changes but little. The great and +important difference is in the climate, the winters being much more +severe in these mountains in the northern part of the State than in the +southern, and the summers much more liable to sudden changes of weather. +Scott, Fentress, and Morgan counties comprise this portion of the table, +and these have not been included in my examination, excepting as to +general features. + +In all our southern country, and I may say in our whole country, there +is no other large extent of elevated territory which offers mankind +a pleasant living place, a comfortable climate--none too cold or too +hot--and productive lands. We have east of the upper waters of the great +Tennessee River, in our State, and in North Carolina and Georgia, the +great Blue Ridge range of mountains, known as the Unaka, or Smoky, +Chilhowee, Great and Little Frog, Nantahala, etc., all belonging to the +same family of hills. This chain has the same general course as the +Cumberlands. It is a much bolder range of mountains, but it is vastly +less inhabitable, productive, or convenient of access. The winters there +are severely cold, and the nights in summer are too cold and damp for +health and comfort, as I know by personal experience of two summers on +Nantahala River. But the trout fishing is beyond comparison, and that +is one inducement of great value for a stout consumptive _who is a good +fellow_. These mountains are much more broken up into branches, peaks, +and spurs than the Cumberlands. They afford no table terrritory of +any extent. There are some excellent places there for hot summer +visits--Ashville, Warm Springs, Franklin, and others. + +The Cumberland Mountains, as a whole, are flat, in broad level spaces, +broken only by the "divides," or "gulfs," as they are called by the +inhabitants, where the streams flow out into the valleys. + +Walden's Ridge, of which we come now to speak particularly, is the best +located of any part of the Cumberlands as a place for living. From the +separation of this ridge from the main range of Grassy Cove to its +southern terminus at the Tennessee River, it maintains a remarkably +uniform character in every particular. From it access to commerce is +easy, having the Tennessee River and the new (now building) Cincinnati +Southern Railroad skirting its entire length on the east. It rises very +abruptly from both the Tennessee and Sequatchee Valleys, being from +1,200 to 1,500 feet higher than the valleys on each side. Looking from +below, on the Tennessee Valley side, the whole extent of the ridge +appears securely walled in at the top by a continuous perpendicular wall +of sandstone, from 100 to 200 feet high; and from the Sequatchee side +the appearance is very similar, excepting that the wall is not so +continuous, and of less height. + +The top of the ridge is one level stretch of plain, broken only by the +"gulfs" before mentioned and an occasional prominent sandstone wall or +bowlder. The width on top is, I should judge, 6 or 7 miles. The soil is +of uniform character, light, sandy, and less productive for the ordinary +crops of the Tennessee farmer than the soil of the lowlands. The grape, +apple, and potato grow to perfection, better than in the valleys, and +are all never failing crops; so with rye and buckwheat. Corn grows +well, very well in selected spots, and where the land is made rich +by cultivation. The grasses are rich and luxuriant, even in the wild +forests, and when cultivated, the appearance is that of the rich farms +of the Ohio or Connecticut Rivers, only here they are green and growing +the greater part of the year; so much so that sheep, and in the mild +winters the young cattle, live by the wild grasses of the forests the +whole year. The great stock raisers of the Sequatchee and Tennessee +Valleys make this the summer pasture for their cattle, and drive them to +their own farms and barns or to market in winter. The whole Cumberland +table, with the exception of that small part which is under cultivation, +is one great free, open pasture for all the cattle of the valleys. +Thousands of cattle graze there whose owners never pay a dollar for +pasturage or own an acre of the range, though, as a rule, most of the +well-to-do stock farmers in the valleys own more or less mountain lands. +These lands have, until quite recently, been begging purchasers at from +12½ to 25 cents per acre in large tracts of 10,000 acres and upward, and +perhaps the same could be said of the present time, leaving out choice +tracts and easily accessible places, which are held at from 50 cents to +$2 per acre, wooded virgin lands. + +The forest growth of Walden's Ridge is almost entirely oak and chestnut. +Hickory, perhaps, comes next in frequency, and pine after. There is but +little undergrowth, and where the forests have never been molested there +are but few small trees. This is due to the annual fires which occur +every autumn, or some time in winter, almost without exception, and +overrun the whole ridge. It does not rage like a prairie fire. Its +progress is usually slow, the material consumed being only the dry +forest leaves and grasses. The one thing essential to its progress is +these dry leaves, hence it cannot march into the clearings. Nearly all +the small shrubs are killed by these fires, otherwise they are harmless, +and are greatly valued by the stock men for the help they render in the +growth of the wild grasses. The free circulation of air through these +great unbroken forests is certainly much facilitated by these fires, +since they destroy every year what would soon become impediments. The +destruction of this undergrowth leaves the woods open, and the lands are +mainly so level that a carriage may be driven for miles, regardless of +roads, through the forests in every direction. + +The shrubs about the fields and places where the forests have +been interrupted by civilization and other causes are blackberry, +huckleberry, raspberry, sumac, and their usual neighbors, with the +azalia, laurel, and rhododendron on the slopes and in the shade of the +cliffs. + +The kinds of wild grasses, I regret to say, I have not noted, and the +same of the rich and varied display of wild flowers. + +The whole ridge is well supplied with clean, soft running water, even +in the driest of the season. There are no marshes, swamps, or bogs, no +still water--not even a "puddle" for long--for the soil is of such a +character, that surface water quickly filters away into the sands and +mingles with the streams in the gulfs. Springs of mineral water are +abundant everywhere. Probably there is not a square mile of Walden's +Ridge which does not furnish chalybeate water abundantly. Sulphur +springs with Epsom salts in combination are nearly as common. + +The entire extent of Walden's Ridge is underlaid with veins of coal, and +iron ore is plentiful, especially in the foot hills. The coal and iron +are successfully mined in many places on the eastern slope; on the +western they are nearly untouched for the want of transportation. I find +that the impression prevails that the minerals of the Cumberlands are +largely controlled by land agents and speculators. This is only true as +applied to a very small part of the whole, not more than 1 per cent. The +mineral ownership remains with the lands almost entirely. + +The prevailing winds on Walden's Ridge are from the southwest; northers +and northeasters are of rare occurrence. One old lady who had resided +there for forty years, in answer to my query upon this subject, said: +"Nine days out of ten, the year round, I can smell Alabama in the air." +This was the usual testimony of the residents. Winds of great velocity +never occur there. In summer there is always an evening breeze, +commencing at 4 to 6 o'clock, and continuing until after sunrise +the next morning. In times of rain, clouds hang low over the ridge +occasionally, but they never have fogs there. + +The range of the thermometer is less on the Tablelands than in the +adjacent valleys. I have had access to the carefully taken observations +of the Lookout Mountain Educational Institute, such published accounts +as have been made by Professor Safford, State Geologist, Mr. Killebrew, +the thorough and painstaking private record of Captain John P. Long, +of Chattanooga, and many more of less length of time. From all these I +deduce the fact that the summer days are seven or eight degrees cooler +on the mountains than in the Tennessee Valley at Chattanooga, and five +or six degrees cooler than in the Sequatchee Valley, as far up as Dunlay +and Pikeville. The nights on the table are cooler than in the lower +lands by several more degrees than the days; how much I have thus far +not been able to state. The late fall months, the winter, and early +spring are not so much colder than the valleys as the summer months, the +difference between the average temperature of the mountains and valleys +being at that time four or five degrees less than in the summer. There +is no record of so hot a day ever having occurred on the Cumberladd +Mountains as to cause mercury to run so high as 95° F., or so cold a day +as to cause it to run so low as 10° below zero. + +In the average winter the ground rarely freezes to a greater depth than +2 or 3 inches, and it remains frozen but a few days at a time. Ice has +been known to form 8 inches thick, but in ordinary winters, 3 or 4 +is the maximum. Snow falls every winter, more or less, and sometimes +remains for a week. Old people have a remembrance of a foot of snow +which lasted for a week. + +Walden's Ridge has a total population of a little more than 4,000, +scattered over 600 square miles of surface. The number of dwellings is +about 800. Ninety per cent. of these are log houses; 70 per cent. of +them are without glass windows; light being furnished through the +doorways, always open in the daytime, the shuttered window openings, and +the open spaces between the logs of the walls. Less than 2 per cent. of +these houses have plastered walls or ceilings, and less than 5 per cent. +have ceiled walls or ceilings. About 20 per cent. of them are fairly +well chinked with clay between the logs, the remainder being but +indifferently built in that particular. Fully 90 per cent. of these +abodes admit of free access of air at all times of day and night, +through the floors beneath as well as the walls and roof above. It is +the custom of the people to guard against the coldest of days and nights +by hanging bed clothes against the walls, and many good housewives have +a supply of tidy drapery which they keep alone for this purpose. + +Wood, always at hand, is the only fuel in use. The whole heating +apparatus consists in one large open fireplace, built of stone, +communicating with a large chimney outside the house at one end, and +frequently scarcely as high as the one story building which supports it. +This chimney is constructed in such a manner as to be a great ventilator +of the whole room, quite sufficient, it would be thought, if there were +no other means of ventilation. It is usually made of stone at the +base, and that part above the fire is of sticks laid upon one another, +cobhouse fashion, and plastered over inside and between with similar +clay as that with which the house walls are chinked. + +Very few of these houses are more than one story high. They are all +covered with long split oak shingles--the people there call them +"boards"--rifted from the trunks of selected trees. There is no +sheathing on the roof beneath these shingles. They are nailed down upon +the flat hewn poles running across the rafters, at convenient distances. +Looking up through the many openings in the roof in one of these house, +one would think that this would be but poor protection against rain, but +they rarely leak. + +Not one family in fifty is provided with a cooking stove. They bake +their bread in flat iron kettles, with iron covers, covered with hot +coals and ashes. These they call ovens. The meat is fried, with only the +exception of when accompanied by "turnip greens." + +The question, "What is the principal food of the people who live on +these mountains?" has been asked by me several hundred times. The +almost invariable answer has been, "Corn bread, bacon, and coffee." +Occasionally biscuits and game have been mentioned in the answers. All +food is eaten hot. Coffee is usually an accompaniment of all three +meals, and is drunk without cream and often without sugar. Some families +eat beef and mutton for one or two of the colder months in the year on +rare occasions, though beef is commonly considered "onfit to go +upon," as I was told upon several occasions, and mutton sustains less +reputation. Chickens are used for food while they are young and tender +enough to fry, on occasions of quarterly meetings, visits of "kinfolks" +or the "preachers" and the traveling doctors. Fat young lambs are plenty +in many settlements from March to October, and can be had at fifty cents +each, but I could not learn that one was ever eaten. + +A large majority of the adult population use tobacco in some shape--the +men by chewing or smoking, the women by smoking or dipping snuff. They +never have dyspepsia, nor do they ever get flesh, after they pass out of +childhood, though nearly all the children are ruddy in appearance, and +well rounded with fat. + +One physical type prevails among the people in middle life, and carries +along into old age but little change; and old age is common there. +Nearly every house has its old man or old woman, or both. Everybody, +father and mother, and frequently grandfather and grandmother, is still +on hand, looking as brisk and moving about as lively as the newer +generations. After they pass their forty years, they never seem to +grow any older for the next twenty or thirty, and the grandfathers and +grandmothers can scarcely be selected, by comparison, from their own +children and grandchildren. The men are taller than the average, and +the women, relatively, taller than the men. They are all thin featured, +bright eyed, long haired, sharp looking people, with every appearance of +strength and power of endurance. + +I think the men who live on Walden's Ridge can safely challenge the +world as walkers--aborigines and all; and unless the challenge should be +accepted by their own women folks, I feel quite sure they would "win the +boots." They go everywhere on foot, and never seem to tire. + +Nearly all the people of the Tablelands are employed in the pursuits of +agriculture. Very few of them seem to be hard workers. The men are all +great lovers of the forest sports, much given to the good, reliable, old +fashioned long rifles. The women and children are much employed in out +door occupations, and live a great portion of their time in the open +air. The clothing of all classes is scanty. The use of woolen fabrics +for underwear has not yet been introduced, and coarse cotton domestic +is the universal shirting, and cotton jeans, or cotton and wool mixed, +constitute the staple for outer wearing apparel. The men wear shoes +throughout the year much more commonly than boots. They never wear +gloves, mittens, scarfs, or overcoats, and they scorn umbrellas. +Probably this whole 4,000 people do not possess two dozen umbrellas or +twice as many overcoats. The women go about home with bare feet a great +part of the summer. They never wear corsets or other lacing. + +I have learned by careful inquiry that very few of the people of the +Ridge have ever had the diseases of childhood. Scarlet fever I could +hear of in but two places, and I suppose that not one person in fifty +has had it. Whooping cough and measles have occurred but rarely, and the +large majority have not yet experienced the realities of either. Very +few people there have ever been vaccinated, nor has smallpox ever +prevailed. Typhoid, typhus, and intermittent fevers are unknown. In the +great rage of typhoid fever which took place ten or twelve years ago in +the Tennessee and Sequatchee Valleys, not a single case occurred on the +Mountains, as I have been informed by physicians who were engaged in +practice in the neighborhood at the time. Diphtheria has never found a +victim there; so of croup. Nobody has nasal catarrh there, and a cough +or a cold is exceedingly rare. + +I have said that these observations refer more particularly to Walden's +Ridge than to the Cumberland Tablelands in our State as a whole. This +ridge was chosen by me for this examination, mainly for the reason of +its convenience, but partly owing to its being more generally settled +than any other equal portion of the table which lies in Tennessee. +Lookout Mountain is not as well located; it is on the wrong side of the +Tennessee River, and but a few acres of it belong in this State. Sand +Mountain is altogether out of the State, but it is perhaps nearer like +Walden's Ridge in its physical features than Lookout. That part of the +Cumberlands west of Sequatchee Valley is Walden's Ridge in duplicate, +excepting that it is further west, and nearer the Middle Tennessee +basin. There are some small towns, villages of miners, and summer +resorts there, which interferes with that evenness of the distribution +of population which Walden's Ridge has, rendering it more liable to +visitations of epidemic and contagious diseases. The tablelands north +of the center line of the State, above Grassy Cove, are very similar +to Walden's Ridge, as far up as Kentucky, with the exception before +mentioned--that of climate--it being from one to ten degrees colder in +winter. + +This whole Cumberland Table is no small country. It comprises territory +enough to make a good sized State. At present, it is almost one great +wilderness, in many particulars as unknown as the Black Hills. It is +coming into the world now, and will be well known in a few years. The +great city of Cincinnati has determined to build a railroad through +the very center of this great table in the north part of the State, +connecting with Chattanooga in the southern part. This road is nearly +bored through, and in another year or two the Cumberland Tablelands in +Tennessee will be much heard of at home and abroad. + +It seems to me this country has merits. It is located in the latitude of +mild climate; not so far south as to be scorched by the hot summer sun, +or visited by the great life destroying epidemics; not so far north as +to meet the severe and lengthened winters. + +Climate, we know, is a fixture; it has a government; it has rules; the +weather may change, but climate does not; it is a permanent out-door +affair, and what is true of to-day was true centuries ago, and will +be true forever, in the measure of any practical scope, at least. The +people of the world are beginning to know that the greatest destroyer of +human life has its remedy in climate. + +Mr. Lombard, in his famous exhibit in relation to the prevalence of +consumption among the people of different occupations, circumstances of +life, and place of dwelling, gives the lowest number of deaths from this +cause to those who live in the open air. He found the people who lived +most in the open air, as would be readily conjectured, in the mild +latitudes, not in the countries of hot sands or cold snows. + +[The above article, in regard to which we have noticed frequent +allusions in many of our exchanges, all erroneously attributing it to +_Dr. Wright_, of Tennessee, and for which we have received repeated +requests quite recently, was read by the lamented Dr. E.M. Wight at +the 43d annual meeting of the Tennessee State Medical Society, held +at Nashville, April 4, 5, and 6, 1876. Its distinguished and talented +author will long be remembered as one of the most active, earnest, and +zealous members of the State Society. At this meeting he also read a +very admirable paper on "The Microscopic Appearance of the Blood in +Syphilis," and prepared the report of the Committee on State Board +of Health, to which report may be ascribed the honor of securing the +necessary legislation organizing the Board. A true, upright, honest man, +an earnest, devoted and zealous physician, universally esteemed and +beloved by all who knew him; himself the subject of tuberculosis, dying +in the prime of a brilliant manhood. He had but few equals in the +glorious profession he honored and loved so well. + +From a careful reading of his paper, we find that he describes a large +area of territory, free, absolutely free, from subsoil moisture, a +climate mild and equable, a soil capable of producing nearly everything +necessary for the comfortable maintenance of human life, surroundings +that tempt, nay, compel the greatest possible amount of open air +life. His description is exceedingly accurate of a plain, primitive, +simple-minded people with but few wants, many of the virtues and few +of the vices of humanity. With their surroundings, soil, climate, +residence, and mode of living, need we be surprised that "there is +a people," or a land "free from consumption"?--ED.]--_Southern +Practitioner_. + + * * * * * + + + + +THE TREATMENT OF HABITUAL CONSTIPATION. + + +Dr. F.P. Atkinson thus writes in the _Practitioner_, January, 1884: I +suppose there is no derangement of the system we are more frequently +called upon to treat than habitual constipation; and though all kinds of +medicines are suggested for its relief, they rarely produce more than +temporary benefit--and it is difficult to see how the result can well be +otherwise, while the root of the evil remains untouched. Now by far the +more numerous subjects of this disorder are women; and as they do not +seem to know that regularity is essential to the performance of every +one of nature's operations, they appoint no stated times for trying to +get the bowels relieved, but trust to receiving intimation when the +rectal accumulation and distension can be borne no longer. This method +of action may and does answer fairly well for a time; but nature +gradually gets upset, the sensation of the lower bowel becomes blunted, +and at last it ceases to respond to the ordinary stimulus. Then +aperients are regularly resorted to, and although these act fairly +well for a time, they gradually have to be increased in strength +and frequency. Now, as regards the treatment, the first thing to be +accomplished is of course to get the rectum well relieved; the next, +to get the actions to take place at fixed times; and lastly, it is +necessary to get more tone imparted to the muscular tissue of the +bowels, so that the regularity of action may be helped and also +maintained. In order, then, to get the bowels relieved in the first +instance, it is well to give five grains of both compound colocynth and +compound rhubarb pill at bed-time (this rarely requires to be repeated), +then to take a tumblerful of cold water the next morning on waking, and +repeat it regularly at the same time each day. Should the bowels remain +sluggish for some time, the same quantity of water may be taken daily +before each meal. Supposing no action takes place on rising or shortly +after, a small injection of warm water may be resorted to. After each +movement of the bowels, a small hand-ball syringeful of _cold_ water +should be thrown into the rectum and retained. A soup plateful of coarse +oatmeal porridge (made with water and taken according to the Scotch +method, viz., by filling half the spoon with the hot porridge and the +other with cold milk) each night at bed-time, or even every night and +morning for a time, is often a very great help. But above all things, +it is necessary for the patient to _try_ and get relief at a certain +_fixed_ time regularly every day. If these directions are strictly +carried out in their entirety, the evil, even if it has been of long +standing, will generally be corrected, and the patient will improve in +health and appearance. Of course where the constipation results from +exhaustion of the nervous system (such, for instance, as is brought +about by self-abuse), the special cause has to be taken into +consideration, and such treatment adopted as is suited to the particular +necessities of the case. + + * * * * * + + + + +THE PYRAMIDS OF MEROE. + + +About fifty miles from the mouth of the Atbara, and, of course, on the +eastern bank of the Nile, stand the pyramids of Meroe. They consist +of three groups, and there are, in all, about eighty pyramids. The +presumption is that they represent the old sepulchers of the kings of +Meroe. Candance, Queen of the Ethiopians, mentioned in Acts, chap. +viii., v. 27, is supposed to have belonged to Meroe, that being the name +also of the capital, which is understood to have been somewhere not far +distant from the sepulchers. These pyramids of Meroe possess one marked +feature, distinguishing them from the pyramids of Egypt proper--that is, +they have an external doorway or porch. As there is no entrance to the +pyramid at these porticoes, it is quite possible that they were temples +for worship or making offerings to the dead. By comparing them with +the pyramids of Ghizeh, it will be seen that they are also taller in +proportion to their base. Another important point in these porches +or temples is the existence of the arch; and that, too, an arch in +principle, with a keystone.--_Illustrated London News_. + +[Illustration: THE PYRAMIDS OF MEROE, ON THE NILE.] + + * * * * * + + + + +THE PROLIFICNESS OF THE OYSTER. + + +In an article by Prof. Karl Mobius on "The Oyster and Oyster Culture," +reproduced in the recently issued report of the U. S. Commissioner of +Fish and Fisheries, the author says: + +A mature egg-bearing oyster lays about one million of eggs, so that +during the breeding season there are upon our oyster beds at least +2,200,000,000,000 young oysters, which surely would suffice to transform +the entire extent of the sea-flats into an unbroken oyster bed; for if +such a number of young oysters should be distributed over a surface 74 +kilometers long by 22 broad, 1,351 oysters would be allotted to every +square meter. But this sum of 2,200,000,000,000 young oysters is +undoubtedly less than that in reality hatched out, for not only do those +full-grown oysters which are over six years of age spawn, but they begin +to propagate during their second or third year, although it is true that +the young ones have fewer eggs than those which are fully developed. At +a very moderate estimation, the total number of three to six year old +oysters which lie upon our beds will produce three hundred billions of +eggs. This number added to that produced by the five millions of full +grown oysters would give for every square meter of surface not merely +1,351 young oysters, but at least 1,535. In order to determine how +many eggs oysters produce, they must be examined during their spawning +season. This begins upon the Schleswig-Holstein beds in the middle of +June, and lasts until the end of August or beginning of September. The +spawning oyster does not allow its ripe eggs to fall into the water, as +do many other mollusks, but retains them in the so-called beard, the +mantle, and gill-plates until they become little swimming animals. The +eggs are white, and cover the mantle and gill-plates as a semi-fluid, +cream-like mass. As soon as they leave the generative organs the +development of the germ begins. The entire yolk-mass of the egg divides +into cells, and these cells form a hollow, sphere-like body, in which an +intestinal canal arises by the invagination of one side. Very soon the +beginnings of the shell appear along the right and left sides of the +back of the embryo, and not long afterward a ciliated pad, the velum, is +formed along the under side. This velum can be thrust out from between +the valves of the shell at the will of the young animal, and used by the +motion of its cilia as an organ for driving food to the mouth, or +in swimming as a rudder. During these transformations the original +cream-white color of the germ changes into pale gray, and finally into a +deep bluish-gray color. At this time they have a long oval outline, and +are from 0.15 to 0.18 of a millimeter in breadth. Over 300,000 can find +room upon a square centimeter of surface. If an oyster in which the +embryos are in this condition is opened, there will be found upon its +beard a slimy coating thickly loaded with grayish-blue granules. These +granules are the embryo oysters, if a drop of the granular slime be +placed in a dish with pure sea water, the young animals will soon +separate from the mass, and spread swimming through the entire water. +When the embryos are at this stage their number may be estimated in the +following manner: The whole mass of embryos is carefully scraped from +the beard of the mother oyster by means of a small hair brush. The whole +mass is then weighed, and afterward a small portion of the mass. This +small portion is then diluted with water or spirits of wine, and the +embryos portioned out into a number of small glass dishes, so that they +can be placed under the microscope and counted. Thus, knowing the weight +of the small portion and the number of embryos in it by count, we can +estimate the total number of embryos from the weight of the entire mass, +which is also known. In this manner I estimated the number of embryos +in each of five full grown Schleswig-Holstein oysters caught in August, +1869, and found that the average number was 1,012,956. + +Notwithstanding this great fecundity, but an extremely small proportion +of the young oysters produced during the course of the summer arrive +at maturity, 421 only out of 500,000,000 escaping destruction. The +immolation of a vast number of young germs is the means by which nature +secures to a few germs the certainty of arriving at maturity. In order +to render the ideas of germ-fecundity and productiveness more easily +understood, Prof. Mobius makes the following comparison between the +oyster and man: + +According to Wappaus, for every 1,000 men there are 347 births. +According to Bockh, out of every 1,000 men born 554 arrive at maturity, +that is, live to be twenty years or more of age; thus, on an average, +347 children are produced from 554 mature men, or 626 children from +1,000 mature men. Since 1,000 full-grown oysters produce 440,000,000 of +germs, then the germ fecundity of the oyster is to the germ fecundity of +man as 440,000,000 to 6.26, or as 7,028,754 to 1. On the other hand, the +number which arrive at maturity is 579,002 times as great with mankind +as with the oyster; for of 1,000 human embryos brought into the world +554 arrive at maturity, or of 440,000,000 newly born 243,760,000 would +live to grow up, while of 440,000,000 young oysters only 421 ever become +capable of propagating their species. The proportion is then 421 to +243,760,000, or as 1 to 579,002. I am fully persuaded that these figures +represent the number of oysters which arrive at maturity more favorably +than is really the case, since from every thousand of full grown oysters +it is certain that, on an average, more than 440,000,000 young are +produced. + + * * * * * + + + + +RED SKY. + + +The beautiful red sky which has been so frequent of late, morning as +well as evening, has excited much comment. The comment, however, has +consisted more of description, statement of fact, theory, and wonder as +to cause, rather than as to satisfactory explanation. + +Facts in the case which would reveal the secret of this beautiful +display of nature are not complete and numerous enough at present to +establish the cause of this phenomenon on a sure basis; yet enough +facts, it would seem, have been obtained to satisfy the strong mind +capable of bridging over a wide expanse. + +Facts in an argument are like piers to a bridge-the more we have of +them, c. p., the more substantial the structure. When the facts are +_legion_, the structure becomes a causeway, and there is no need of +argument. + +Argument is a bridge--the fewer the facts, the more the necessity for +the bridge; the less the facts, the more argument necessary to connect +the few we have, and the more skill is required to make substantial +connecting links between the few solid piers (facts) that exist. + +One of the queer things in connection with this is, the public have +looked chiefly, if not wholly, to the astronomers for an explanation +of this phenomenon, when it is not their special province to explain +matters in this department of nature. + +The explanation belongs to the department of meteorology, and not to +astronomy. But the fact of having looked to the astronomers shows how +little the world knows of meteorology and how few meteorologists +there are able, ready, and willing to rise and explain in face of the +opposition of the public, who seem to think that the explanation must +necessarily belong to astronomy. Astronomy proper deals with the +position of the earth in space and its relation to the other heavenly +bodies, whether suns, fixed stars, planets, satellites, comets, or other +bodies in the vast space about us. Meteorology deals with the atmosphere +of the globe, in all its forms. Astronomy could be studied in the early +ages; its grand facts were not wholly dependent upon the advanced +condition of the mechanic arts; it could be studied even without the aid +of telescopes, though telescopes have added much to its advancement. +Meteorology, on the contrary, depended on the advancement of the arts +and sciences; they must first be perfected ere we could know much about +this branch of science. To one unfamiliar with the advancement and +perfection of meteorology within the past ten years, this statement +may seem strange, yet it is an undisputable fact that, prior to the +establishment of the daily weather reports, the knowledge on this +subject amounted to very little, and was not even worthy of being +designated a science. Prior to the advent of the weather map the world +was in absolute ignorance of the laws governing the atmosphere. Sure, we +had had large volumes on the laws of storms, but the later revelations +leave them shelved high and dry on the shores and as useless as a wreck +in a similar condition; with the daily weather map before us we have no +need to even open these huge volumes; they are completely circumvented, +and only negative in value--to show how little was known of the subject +without the full and complete facts daily collected and spread before us +on the map published by the Weather Bureau. + +In order to understand the color of our sky, we must understand the +subject which is so immediately connected with it and its creation. + +The earth is a sphere in space; generally speaking, it is composed of +land and water. These are two factors; the heat that it derives from +the sun forms a third factor; the three--land, water, and heat--are +essential to life, at least the higher conditions of life which +culminate in man. The old physical geography taught us this much, but +it was not able to go further and tell us why it was cold or warm +independent of the seasons; it could not explain why it was at times as +warm, and even warmer, half-way to the pole than at the equator; why it +was at times very warm in the extreme northeast while very cold in +the Southern States; cold in the northwest when it was warm in the +northeast, and warm in the northwest when cold all along the upper +Atlantic seaboard; it could not forewarn us of storms. These and a +host of other facts, which the weather map makes as plain as astronomy +demonstrates that Jupiter is a planet, the new revelation, through the +instrumentality of the perfected telegraph system, makes exceedingly +plain to us if we will but seek the easily obtained information. + +The principal revelations of the weather map are the facts in regard to +the areas of high and low barometer, and the influence they exert upon +the climate of the globe. + +These conditions--high and low barometer--move on general lines from the +west towards the east, or towards the rising sun, and around the world +in irregular belts. The centers of low barometer are various distances +apart, from a thousand to two thousand and even more miles apart--call +the average about two thousand miles. + +The clouds are formed from the moisture present by the action of the +sun's heat. The direction of the wind is from the area of high barometer +to that of low. The nearer the winds approach the center of "low" (low +barometer), the more they partake of the lines of the volute curve, or +curve of the sea shell or water in a whirlpool. High barometer is the +atmospheric hill; low barometer is the atmospheric valley. But time at +present will not permit more than these general statements; a close +study of the weather map for a season will reveal the beautiful minor +details. + +To the reader it may seem a long way round, yet in order to fully +understand the nature of the atmosphere which surrounds our globe we +must pay due attention to these newly discovered physical laws. + +The red sky which was so noticeable, in the fall of 1883, the +astronomers have told us was due to "meteoric dust" which was produced +by the volcanic eruption on the island of Java, August 27, 1883. + +This "meteoric dust" they say combined with the atmosphere, followed it +around the earth, and caused the beautiful redness of the sky at morning +and evening. For one, I do not believe dust of any description in the +atmosphere would produce such an effect. + +There is nothing luminous, transparent, or delicate about dust. Dust +would not remain in the atmosphere for months, it would settle in a very +short time, and if thick enough in the atmosphere to obstruct the light +of the sun it would be visible, discernible, to the eye, and manifest +on the face of nature. Years ago, before the age of the weather map, we +might have thought that the atmosphere followed the surface of the earth +like the water on a grindstone, but it does not. As already seen, the +wind is from the area of high barometer to that of low, and there are +many of these "low centers." + +From the best calculation we can make at present, there would be at +least some six centers on an average between the center of the United +States and the island of Java. In addition to this there would also be +a number of belts of "low" centers, which would complicate the thing +threefold at least. At all these different centers the winds would be +blowing from all points of the compass at the same time. Such winds +would not be apt to bring the "meteoric dust" from Java to the United +States, either in an easterly or westerly direction. But, it is said, +"dust" has been gathered. + +How high from the surface of the ground has this _dust_ been +gathered--at what elevation? + +There is undoubtedly a little dust in the air most of the time, but I do +not think that it extends very high. Where it would be the highest and +most perceptible would be on the arid plans of Africa and Asia, when +the _simoom_ is passing, or in the track of a tornado. But from the +multiplicity of these storm centers and the varied winds they would +produce even this dust could not travel from Java to America. + +Again, all clouds, no matter how high or how low, are affected by the +low centers, as the movement of clouds prove, and travel from the "high" +to the "low," from and to all points of the compass. High authority +gives the heights of the clouds as follows: lower clouds, 16,000 feet; +upper clouds, 23,000 feet. + +As all clouds, from the highest to the lowest, are affected by the +centers as above referred to, it follows that if this "meteoric dust" +follows the earth around, as it would have to do in order to make good +this theory, it would have to travel suspended in the atmosphere above +the upper clouds, or at a height of more than 23,000 feet, or at an +elevation of over four miles! + +Now, is it reasonable to believe that dust, however fine, will remain in +the atmosphere at that elevation for over six months? + +As a side argument it is suggested that the smoke of the burning woods, +or few years ago in Michigan, caused as peculiar condition of the +atmosphere. This extensive fire was on a day when the area of low +barometer was on a high line of latitude and passing to the eastward. +This naturally took the smoke, which is far lighter than dust, along +with it. It mingled with the muggy condition of an extensive "low," and +produced a yellowness of the atmosphere. This however was of only a few +hours' duration, and was only visible in favorable localities. + +Here again we see the advantage of the weather maps; but for this map we +would never have been able to have satisfactorily explained the peculiar +phenomenon produced by the great Michigan fire. + +If the delicate redness of the sky is not caused by dust, what is it +caused by? + +But for the weather map, I think we should still be in the dark in +regard to it. + +In the first place, this redness is nothing new, only the conditions +are more favorable sometimes than at others. It has always existed and +always will exist, independent of earthquakes, volcanoes, etc. Nature +is ever changing; the movements of the atmosphere more resemble the +kaleidoscope than any thing else. + +The summer and fall of 1883, the movements of "high" (high barometer) +over the United States were quite central and extensive, causing this +peculiar phenomenon over a wide extent of territory. + +We have no information of the condition of the barometer over the other +part of the world; we speak move particularly of the United States; yet +if certain conditions produce certain effects here, it is quite safe to +say that the same effects are produced by the same cause elsewhere. + +As now well established by the map, the surface wind is from the area +of high barometer to that of low--from the atmospheric hill to the +atmospheric valley. + +The tendency of this is to free "high" of all clouds and moisture; but +then it is impossible to free "high" entirely of moisture; a little +will remain, and it is just this little, which is highly rarefied, that +produces the result. We look around us and above, we see little or no +evidence of evaporation, yet it is the while going on. When the sun is +immediately below the horizon, where it will shine horizontally through +the mass of light, suspended moisture, the delicate presence of vapor +heretofore unnoticed is revealed. The action of the sun's rays is the +same as when illuminating a well formed cloud--it is an embodiment +of the same principle, but the material is much more expanded. The +particles of suspended moisture are very fine, few and far between, +therefore the effect of the light upon it is more diffused and +transparent. It is much like looking through a piece of window glass +flatwise and endwise; flatwise we do not perceive any color; endwise, +from seeing through a greater mass, the glass has a very perceptible +green color. + +We see the same idea also in the rising and setting sun and moon. On +a clear, cloudless night, when nothing seems to interfere with the +brightness of the stars, we cannot, by looking upward, perceive any +moisture present in the atmosphere; but if we cast our eyes to the +horizon, whereby we see through the mass of atmosphere endwise, as it +were, and note the appearance of the stars there, or the rising or +setting moon, we will see that the atmosphere there gives a redness +to the rising body, which it does not have when it has ascended to +mid-heaven. On a clear night, which is caused by the presence of the +area of high barometer, the moon when in mid-heaven is of a clear, +silver-white, and it is the same moon that at the horizon was a deep +red. The color of the moon has not changed; it is simply the medium +through which it is seen that produces the difference in color. + +Occasionally, on a clear, bright ("high") night, when the moon is full, +prior to rising, when just below the horizon, it will so illuminate this +lower strata of atmosphere as to appear like a great fire; the moon +rises red, but its deep color gradually fades as it rises, and when well +up in the heavens we perceive that this deep coloring was an illusion +and merely the influence of its surroundings. I never, though, knew of +any one to attempt to account for this by "meteoric dust;" and yet it is +an embodiment of the same principle. Place the sun where the moon is, +and from its far superior abundance of light we have a much grander +display. + +Under no other conditions or relations of the sun and earth is it +possible to have this phenomenon of the delicate red sky but when a +positive area of high barometer is passing and extends over us. In +order to produce this effect we must have the clear atmosphere of high +barometer, when there is a minimum of moisture present. The action of +the sun's rays upon this extensive area of slightly moist rarefied +air is unconfined by clouds, and reaches far and wide, and produces +a delicacy of color which from no other source or condition can be +realized. + +ISAAC P. NOYES. + +Washington, D. C., 1884. + + * * * * * + + + + +A THEORY OF COMETARY PHENOMENA. + + +_To the, Editor of the Scientific American_: + +The following subject, substantially, was written more than a year ago +with a view to its publication. It was not, however, until January of +the present year that I sent a brief communication to the _Brooklyn +Eagle_, which was published Feb. 3, giving my views in relation to +cometary phenomena. With this I might remain satisfied, were it not +that the interesting paper by G. D. Hiscox, published in the SCIENTIFIC +AMERICAN SUPPLEMENT, Feb. 16, impressed me with the idea that the theory +I advanced might assist in explaining others, if brought to the notice +of those interested through the columns of your valuable journal. + +The theory that I advance to account for the several phenomena relating +to comets' tails is, that comets are non-luminous, transparent bodies; +that they transmit the light of the sun; that the transmitted light +reflected by the particles of matter in space constitutes the tails of +comets. "Like causes produce like effects." By contraries, then, like +effects must be produced by similar causes; for, if an effect produced +by a cause which is known is similar to an effect produced by a cause +which is not known, the cause which is known must be similar to the +cause which is not known. This is true or not. + +I submit the following experiments to substantiate the theory advanced. + +Partially fill a vial or a tumbler with water, hold it by the rim, +and move it around a lighted candle placed upon a table. A shadow +surrounding the transmitted light will be cast upon the table. As the +tumbler approaches the light, the shadow follows the tumbler, and when +receding the tumbler follows the shadow; and as the tumbler is moved +around the light, the shadow will swing round from one side to the +other. If the tumbler be held so that a puff of smoke can be blown +into the transmitted rays, the particles of smoke will reflect the +transmitted light, and will illustrate my idea of what constitutes a +comet's tail. A dark band may be observed in this stream of light, as +also in the light cast upon the table. + +In these experiments, we see the effects produced by a cause which is +known; the effects are similar to those observed in the tails of comets, +the cause of which we do not know; but is it not reasonable to assume +that the cause is similar? + +Assuming now that comets are transparent, can any other phenomena +peculiar to comets be accounted for upon this hypothesis? Next to +the tail itself, the curve is the most noticeable feature, and if we +consider the extraordinary length of these appendages, the astounding +velocity at which comets move in their orbits, and the time that would +elapse before a ray of light, emitted from the nucleus, would reach the +end of the tail, perhaps the curve--which, if I am not deceived in my +observations, always dips toward its orbit--can be accounted for. If a +comet moved in a direct line toward the center of the sun, there would +be no curve to the tail. But taking Donati's comet of 1858 as an +example, the tail of which was said to be about 200,000,000 miles long, +a ray of light traveling at the rate of 192,000 miles per second would +be about twenty minutes in going from the nucleus to the end of the +tail. + +But during that time the comet would move in its orbit, say, 50,000 +miles, and as light moves in a straight line, and other rays are +constantly emerging from the nucleus as it moves along in its course, +the result is that the tail has a curved appearance. + +I have no data at hand regarding this comet, but what I have said will +serve to illustrate my ideas. Again, referring to this comet, I remember +to have read the statement of an astronomer that, after passing round +the sun, a new tail was formed opposite the original one. Now, it seems +to me that that is just what would happen, for in moving round the sun +the comet would travel say 3,000,000 miles; the greater portion of the +tail then, would extend millions of miles upon one side of the sun, +while from the nucleus upon the opposite side of the sun a new tail +would appear to be formed. + +Upon this hypothesis, the extraordinary length of their tails and the +fact that stars are visible through the densest portion of them is +explained; as also the fact that they so rapidly disappear from view +when moving from the sun, the light received by them from the sun +being in proportion to their distance from it, and but little of that +reflected. + +JOHN M. HUGHES. + +Brooklyn, N. Y. + + * * * * * + +[FOR THE SCIENTIFIC AMERICAN.] + + + + +ON COMETS. + + +When we see a comet approaching the sun with its tail following in the +orbit of the nucleus, we have no great difficulty in believing the +common theory that a comet consists of nucleus attracted toward the sun, +while the tail is repelled; and that we see the whole of it. But as it +approaches the sun, difficulties arise that make us doubt whether the +theory be true. + +Let us suppose a comet with a tail 50,000,000 miles in length, and that +it will require two days to pass round the sun. Now the tail, being +always in a line drawn through the center of the sun and center of the +nucleus, will, when it reaches the long axis of the elliptical orbit, +stand perpendicularly to the orbit of the nucleus. That is, the +extremity of the tail farthest from the sun, in addition to its onward +motion, has acquired a lateral motion that has lifted it 50,000,000 +miles in the first day of its perihelion. The velocity of the extremity +has been vastly accelerated over that of the nucleus, and it has +moreover a sheer lift above the orbit of the nucleus. Now this lift is +in opposition to gravity; neither is it in consequence of any previous +momentum, for its velocity is accelerated and its previous momentum +would be a hindrance; nor is the lift in consequence of any repelling +force from the sun, for such force would be diminished in proportion to +the square of the distance, and the far end would be acted on less than +the nucleus end of the tail, whereas the velocity of the former is +increased a hundred fold over that of the latter. A polar force in the +comet would merely draw the comet into the sun. We therefore find no +force adequate for such a lift, but on the contrary all the forces are +opposed to it. + +But if the first day of the perihelion overwhelms us with difficulty, +the second day will prove disastrous to the common theory. For the +extremity of the tail farthest from the sun will be required to pass +with lateral motion from its perpendicular 100,000,000 miles, so that it +may be in advance of the nucleus and again rest on its orbit. This orbit +is an impassable line, and therefore instantly arrests the prodigious +lateral velocity of the tail. That impassable orbital line is to it +as solid and inflexible as a wall of adamant. The motion so instantly +arrested would be disastrous to any tail, whether composed of gas, +meteorites, or electricity, whatever that may be. + +Having shown that the common theory of comets is filled with insuperable +difficulties, I will again call attention to a theory proposed about +eighteen months ago in the SCIENTIFIC AMERICAN. + +According to this theory, a comet consists of a nucleus and an +atmosphere, for the most part invisible, surrounding it on all sides to +an extent at least equal to the length of the tail. The rays of the sun +in passing through or near the nucleus are so modified as to become +visible in their further progress through the cometic atmosphere, while +all the rest remain invisible. What we call the tail is merely a radius +of the cometic atmosphere made visible, and as the comet moves through +space, only different portions of the atmosphere come in sight, in +obedience to the ordinary laws of light. There is no difficulty in +accounting for the rise and fall of the tail at perihelion, nor for the +tail preceding the nucleus afterward. + +The spherical theory accounts easily for the different forms of tail +seen in different comets. The sword shaped tails, at variance with the +common theory, can be accounted for by supposing a slight difference in +density or material in the cometic atmosphere, which will deflect the +light as seen. The comet of 1823, which cannot be explained on the +common theory, is very easily explained on the spherical. That comet +showed two tails, apparently of equal length, which moved opposite to +each other, and perpendicularly to the orbit of the nucleus, and showing +no signs of repulsive force from the sun. On the spherical theory it is +only necessary to suppose such an arrangement of the nucleus as would +reflect the rays of the sun laterally; a slight modification of the +nucleus would give not only two but any number of tails pointing in +different directions. + +It may be objected to the spherical theory that a tail 50,000,000 miles +long would call for a sphere 100,000,000 miles in diameter, and that +would be too vast for our solar system. But it is claimed for this +sphere that it consists of the same material as the so-called tail, and +that it has the same capability of moving among planets without manifest +disturbance to either. + +The sphere at the perihelion would envelop the sun, and as a noticeable +reduction is sometimes found in its so-called tail, the cometic +atmosphere may impart to the sun at that time whatever is necessary to +its use. + +That there is something in common between the sun's corona and cometary +matter was shown by the last solar eclipse observed in South Pacific +Ocean, where the spectrum of sun's corona was found to be the same as +that of a comet's tail. Are we to attribute in any degree the different +appearances of the sun's corona to the presence or absence of a comet +at its perihelion? At the eclipse of the sun seen in Upper Egypt two or +three years ago, a comet was seen close to the sun, but I have seen no +account of the appearance of the corona at that time. + +FURMAN LEAMING, M.D. + +Romney, Tippecanoe Co. Indiana. + + * * * * * + + + + +FORMS OF IVY. + + +It is scarcely possible for us to bee too emphatic in our praises of the +most distinct forms of ivy, since but few other hardy climbing plants +ever give to us a tithe of their freshness and variety. A good long +stretch of wall covered with a selection of the best green-leaved kind +is always interesting, and never more so than during the winter months, +especially if at intervals the golden Japanese jasmine is planted among +them or a few plants of pyracantha or of Simmon's cotoneaster for the +sake of their coral fruitage. The large-leaved golden ivy is also very +effective here and there along a sunny wall, especially if contrasted +with the small-leaved kind--atropurpurea--which has dark purple or +bronzy foliage at this season. Of the large-leaved kinds, one of the +most distinct is canariensis, or large-leaved Irish ivy, and Raegner's +variety, with leathery, heart-shaped foliage, is also handsome. The +birdsfoot ivy (pedata) is curious, as it clings to the stones like +delicate leaf embroidery, and for shining green leafage but few equal +to the one called lucida. The two other kinds sketched are hastata and +digitata, both free growing and distinct sorts. + +[Illustration: VARIOUS FORMS OF IVY. Heart-leaved Ivy (Hedera +Raegenerana). Glossy Ivy (H. lucida). Arrow-leaved Ivy (H. hastata).] + +_Ivy Leaves_.--Common ivy is tolerably plentiful nearly everywhere, but +it is not common to find a good distinct series of its many varieties +even in the best gardens. Of all the different forms of ivy, I think +the large-leaved golden one of the best; certainly the best of the +variegated kinds. Raegner's variety is also very bold, its great glossy, +heart-shaped leaves most effective. Algeriensis is another fine-leaved +kind, the form dentata producing foliage even still larger when well +grown. For making low evergreen edgings on the turf, for carpeting +banks, the covering of bare walls and the old tree stumps, we have no +other evergreen shrub so fresh and variable, or so easily cultivated as +are these forms of the ivy green. Perhaps one reason why the finer kinds +of ivy are comparatively uncommon is the fact that a strong prejudice +exists against ivy in many minds. It is an erroneous notion that ivy +injures buildings against the walls of which it is planted; it never +injures a good wall, nor a sound house, but on the contrary, hides and +softens the stony bareness of the one and adds beauty and freshness to +the other.--_The Garden_. + +[Illustration: VARIOUS FORMS OF IVY. Finger-leaved Ivy (H. Itata). Irish +Ivy (H. canariensis). Rira's foot Ivy (H. pedata).] + + * * * * * + + + + +PROPAGATING ROSES. + + +In an article on this subject an English horticultural journal describes +the method pursued by a London florist. After stating that out of a case +containing 310 cuttings only five failed to root, the article proceeds: +The case or box is made of common rough deal boards. It is five feet +six inches long and one foot in depth. Within half an inch of the top a +groove is cut inside the box, into which the glass is slid, after the +manner of a sliding box lid. In the end of the third week in July the +box was placed in the kitchen garden under the shadow of a high north +wall; it was then about half filled with good turfy loam, to which had +been added a little leaf mould and a good sprinkling of sharp sand. The +soil was then pressed down very firmly (the box being nearly half full +when pressed), and then thoroughly well soaked with rain water, and +allowed to stay uncovered until the next day. The next day good stout +cuttings were taken of all the roses, both tea and hybrid perpetual, +which it was desired to add to the stock. They were then inserted +closely and firmly in the soil, just over the bottom leaf, the glasses +were slipped on and puttied down; the grooves in which the glass slid, +and even the joints in the glass, being filled with putty, so as to +exclude the air. The whole thing completed, nothing more remained to be +done but to leave the box in its cool, shady nook for five or six weeks, +when the growing points of the free starting kinds gave notice that the +glasses might be removed, a bit at a time, with safety. Nothing could be +more simple, or demand less skill, and the operation may be carried out +successfully by an amateur at any time during the season, when good firm +cuttings can be got, and when six weeks' tolerably fine weather may be +counted on. The success of the whole thing depends on having the glasses +fixed so that they may not be removed until the cuttings are rooted, and +in placing the boxes in a shady place. So treated, carnations and many +of our shrubs and herbaceous perennials may be propagated by unskilled +persons with certainty, and without much trouble. + + * * * * * + + + + +A FEW OF THE BEST INULAS. + + +Of the fifty-six species of Inula described in scientific works, +probably not more than thirty are at present in cultivation in +this country, and those are chiefly confined to botanic gardens, +notwithstanding the fact that many of them are useful garden plants. +They are principally distributed throughout Southern Europe, although we +find them extending to Siberia and the Himalayas; indeed, it is to the +Himalayas we are indebted for the kinds that are most ornamental. Some +of the low-growing species are extremely useful for the rockery, such +as I. montana (the Mountain Inula), a fine dwarf plant with woolly +lanceolate leaves and dense heads of orange-colored flowers, resembling +in habit and general appearance some of the creeping Hieraciums. It is a +handsome and desirable plant for the decoration of old walls and similar +places, where it can be a little sheltered from rain and drip. Another +very useful species for this purpose is I. rhizocephaloides, found +plentifully in the Himalayas. It is one of the prettiest Alpine +composites we have. It seldom attains more than from one inch to two +inches in height, forming a dense rosette of short, hairy, oval leaves, +in the center of which the bright purple involucres, in the form of a +ball, are extremely interesting. It is easily cultivated, requiring, +however, a rather snug nook, where it will not be allowed to become too +dry. It is best propagated from seed. Then there is the woolly Inula (I. +candida), a pretty plant with small oval leaves, covered with a thick, +silky down, and much in the way of the white-leaved I. limonifolia, both +of which are very effective when grown in masses, which should always +be low down near the front of a rockery, or as an edging for a mixed +border. The glandular-leaved Inula (I. glandulosa), of which a good +representation is here given, is a beautiful hardy perennial. It is a +native of Georgia and the Caucasian Alps, near the Caspian Sea. It is +a rather robust-growing species, with large, bright, orange-yellow +flowers, varying from three to five inches in diameter, the narrow and +very straggly ray florets contrasting nicely with the rather prominent +disk. The leaves, although quite entire, seem notched, owing to large +black glands which form on their margins. They are lanceolate, and clasp +the stem. The plant is very variable, both as regards robustness and +size of flowers, and this may in a measure account for the confusion +existing between it and I. Oculus-Christi. + +The soil most suitable for the full development of I. glandulosa is a +strong, clayey, retentive loam; it does not thrive well in the light +shallow soils in the neighborhood of London, except in shady positions. +I. Hookeri is a free-flowering perennial, with pointed lanceolate +leaves, of a delicate texture, bright green, and very finely toothed. +The flowers, which are sweet-scented, are not so large as those of I. +glandulosa, and are produced singly, the ray florets being, however, +much more numerous, rarely numbering less than thirty. It is found in +abundance in rocky places in Sikkim, where it replaces the nearly allied +I. grandiflora, a dwarfer species, with much shorter, shining leaves; +both are very desirable plants either for rockery or flower border work. +The Elecampane (I. Helenium) is an imposing, robust-growing species, +having large, broad leaves a foot or more in length. It grows from four +feet to five feet in height, and its thick, shaggy branches are crowned +with large yellow flowers. For isolating in woods this plant, is very +useful, and with the exception of Telekia cordifolia, it would be hard +to find a rival to it. It is, I believe, pretty extensively used for +planting in shrubberies, but unless they are thin and open it is seldom +seen to advantage. It is found wild or naturalized in some parts of +England. It flowers in June and July, and even into August when the +season has been favorable. + +[Illustration: INULA GLANDULOSA (_flowers deep yellow_.)] + +For naturalizing in woods the following will be found useful, _viz_., I. +salicina, I. Oculus-Christi, I. squarrosa, I. britannica, and many more, +the true beauty of which can only be realized in this way. With the +exception of I. rhizocepbaloides, they are all propagated by division +with the greatest ease, or by seed, which is best sown as soon as it is +ripe.--_D.K., The Garden_. + + * * * * * + + + + +FRUIT GROWING. + +By P.H. FOSTER. + + +In the first place, if you contemplate appropriating a portion of your +land for the raising of fruits, you should have the orchard so situated +that no large animals can run at large on the grounds. Prepare your soil +in the most thorough manner; underdrain, if necessary, to carry off +surplus water; dig deep, large holes; fill in the bottom with debris; +in the very bottom put a few leaves, clam and oyster shells, etc., then +sods; above and below the roots put a good garden or field soil; do not +give the trees fresh manure at the time of setting, but the following +fall manure highly with any kind on top of the ground; dig it in the +following spring; keep the soil frequently worked during the summer, +and, if convenient, mulch with hay, straw, or leaves. + +Now you are on the road to progress, provided you have made no mistake +in the selection of your trees. The purposes for which you intend your +fruit is highly important. You should well consider at the outset if +for family or market use. This is a business which requires a long look +ahead, for it is said, "He who plants pears looks ahead for his heirs." + +Caution should be used in procuring your stock; little should be planted +that is not fairly tested on the Island, purchased of parties who can be +fully relied upon to give you what you want. Do not buy your stock of +parties who carry labels in their pockets to make to order what you want +out of the same bundle of trees. + +Now, having your trees set out in a proper manner, of such varieties +as you desire, the next important step is to bring the trees into +usefulness. My plan is to use bone--fine bone--very freely about every +three years. Another important matter is that of trimming. "Fire +purifies," and the knife regulates the grand balance or equilibrium +between roots and tops. In most cases the top outgrows the roots, the +consequence of which is an ultimate weakness of the tree. It is thrown +into excessive fruiting, disease, and premature decay. To avoid this +result, use the knife when required. Thin out the inside branches when +small, and if the tree does not make a satisfactory growth, cut back +half way to the ground. + +We will suppose that you have got your trees growing nicely, and they +have begun to bear fruit. There are other important steps to be taken, +which will be of little cost to you. Provide a wind-break for the +orchard. Evergreens answer the purpose, being a protection against the +wind. Having this matter attended to, there are other enemies with which +we must contend. I refer to the apple and peach tree borers. The former +will live in the tree for three years, if unmolested; the latter, one +year only. They are very easily destroyed by looking over the trees and +taking them out with a knife; or maybe prevented from touching the trees +by wrapping a piece of felt paper, 8 inches wide, around the tree near +the ground, the bottom being covered with dirt and the top tied tightly +above. The pear is not generally disturbed by these insects--only the +apple, peach, and quince. We have another insect very destructive to the +plum, peach, cherry, and apple--the _curcutio_, or plum weavel. This +season for the first time in twenty years we have gathered a small +crop of that very desirable plum, the Purple Favorite. We simply threw +air-slaked lime over the trees nearly every morning for from four to six +weeks, from the time the tree was out of bloom. Peach trees should be +treated in the same manner. Another method of fighting this insect is to +spread a sheet under the tree, and with a blow jar off the little Turk +and secure him on the sheet. But I consider the lime procedure the less +trouble and more effective. The tent caterpillar, which is easily seen, +should be destroyed at once. We have yet another insect to contend with +which infests the apple and pear, commonly called the Coddling Moth, +and the larva, the apple-worm (_Garpocapsa pomonella_). The loss by the +ravaaes of this insect alone to the fruit growers of the United States +fan hardly be estimated, as in many cases the whole crop is rendered +worthless. Such a vast destruction of two of the most valuable fruits +the world produces should stimulate scientists in this age of progress +to discover an effectual remedy against such a gigantic evil. + +I have never yet discovered nor tried an effectual remedy against this +insect. The nearest I have approached his extermination is in the +following manner: After it has entered the fruit and accomplished its +damage, the time arrives when it has to leave the fruit and hide itself +in a quiet, secure position to undergo the transition from the larva to +the pupa state, which requires, in the early part of the season, eight +or ten days; after this time the miller is hatched and is again ready to +besiege the fruit with its sting. The insect, being two-brooded in this +climate at least, if not disturbed, has an aggregating force to do +mischief the second time. The progeny for the succeeding year have alone +to depend on the security of this second generation of larvæ. As they +may often be found in bark of apple trees during winter, my plan of +destruction is, about the first of July to take woolen rags long enough +to wrap around the trees, and say four inches wide. Each week I look +over the trees, and destroy the worms secreted under the rags and +wherever I find them until the fruit is off the trees. I have all the +green fruit, of every kind, carefully picked up as soon as it falls, +thereby destroying many of the curculio as well as the apple-worms. + +One word upon the grape--the insect part of the question. The +_Phylloxera vastatrix_, or grape-vine louse, is already at work on Long +Island. It is found very difficult to raise many of our fine, new grapes +with us in consequence of the depredations of this very minute insect, +it being almost too small to be seen by the naked eye. There has lately +been discovered a remedy which is entirely chemical and as yet but +little disseminated. Very soon, no doubt, a discovery will be made that +will stay the progress of this destructive enemy. + +We should plant aplenty of cherry and small fruit trees to yield feed +for birds. In return they will assist us in our efforts to preserve a +bountiful supply of this health producing element. + + * * * * * + + + + +COARSE FOOD FOR PIGS. + + +A recent subscriber wants advice how to feed pigs of 25 to 35 pounds +weight, that are to be kept over winter and fitted for sale at about six +months old--whether coarse food will not help them as much in winter as +in summer. How roots and pumpkins will answer in lieu of grass, and what +can be fed when this green food is gone? He has had poor success in +growing young pigs on corn alone. He has a reasonably warm pen for +winter. + +The question of food is constantly recurring, and this is one of the +best evidences of the advancement of the country in the feeder's +art. When people are making no inquiry as to improved methods in any +direction, no progress can be made. There has been more progress made +in the philosophy of feeding during the last thirty years than in the +century and a half previous. + +In pig feeding in the dairy districts, young pigs generally grow up in +a very healthy condition, owing to the refuse milk of the dairy, which +furnishes the principal food of young pigs. Skim-milk contains all the +elements for growing the muscles and bones of young pigs. This gave them +a good, rangy frame, and, when desired, could be fed into 400 or 500 +pounds weight. But the fault attending this feeding was, that it was too +scanty to produce such rapid growth as is desired. It took too long to +develop them for the best profit. It had not then been discovered by the +farmer that it costs less to put the first hundred pounds on the pig +than the second, and less for the second than the third, etc.; that it +was much cheaper to produce 200 pounds of pork in six months than in +nine and twelve months. When it became evident that profit required more +rapid feeding, then they began to ply them continually with the most +concentrated food--corn meal or clear corn. If this was fed in summer, +on pasture, no harm was observed, for the grass gave bulk in the +stomach, and the pigs were were healthy and made good progress. But if +the young pigs were fed in pen in winter upon corn meal or clear corn, +the result was quite different; this concentrated food produced feverish +symptoms, and the pigs would lose their appetite for a few days, +drinking only water, which, after a while, would relieve the stomach, +and the pigs would eat vigorously again. Now, had they been fed a few +quarts of turnips, carrots, beets, or pumpkins, to give bulk to the +stomach, and separate the concentrated food, no harm would have come. +This gives the gastric juice a free circulation through the contents of +the stomach, the food is properly digested and applied to the needs of +the body instead of causing fever by remaining in the stomach.--_Live +Stock Journal_. + + * * * * * + + + + +METE KINGI. + + +Our engraving is a portrait of a familiar character in New Zealand, +chief Mete Kingi, who recently died at the age of one hundred years. +He was a fine specimen of the Maori race, the native New Zealanders, a +branch of the Malayo-Polynesian family. The New Zealanders surpassed +all other people in the art of tattooing, to which their chiefs gave +especial attention. Mete Kingi, as our picture shows, was no exception. +Tattooing on the face they termed _moko_. The men tattoo their faces, +hips, and thighs; the women their upper lips; for this purpose charcoal +made from kauri gum is chiefly used. It has the blue color when pricked +into the skin, growing lighter in shade in the course of years. The +subject of our illustration embraced Christianity, and was much +respected. Our engraving is from the _Illustrated Australian News_. + +[Illustration: THE LATE MAORI CHIEF METE KINGI.] + + * * * * * + + + + +LAKE TAHOE. + + +Some very interesting information by Prof. John Le Conte, is given in +the _Overland Monthly_, being the result of some physical observations +made by the author at Lake Tahoe, in 1873. Lake Tahoe, also called Lake +Bigler, is situated at an altitude of 6,247 feet in the Sierra Nevada +Mountains, partly in California, partly in Nevada. The lake has a length +of 22 and a width of 12 miles. As regards its origin, the author regards +it as a "plication hollow," or a trough produced by the formation of two +mountain ridges, afterward modified by glacial agency. The depth of the +lake is remarkable; the observations taken at ten stations along the +length of the lake gave the following depths in feet: 900, 1,385, 1,495, +1,500, 1,506, 1,540, 1,504, 1,600, 1,640, 1645. This depth exceeds that +of the Swiss lakes proper--Lake Geneva, for example, has a maximum depth +of 1,096 feet--but is considerably less than that of Lakes Maggiore and +Como, on the Italian side of the Alps. A series of observations of the +temperature of the water were taken between the 11th and 18th of August. +The average corrected results are as follows: + + Depth in feet. Temp. (C.) + 0(surface).................................19.4 + 50..........................................17.2 + 100..........................................12.8 + 150..........................................10.0 + 200.......................................... 8.9 + 250.......................................... 8.3 + 300.......................................... 7.8 + 330 (bottom)................................. 7.5 + 400.......................................... 7.2 + 480 (bottom)................................. 6.9 + 500.......................................... 6.7 + 600.......................................... 6.1 + 772 (bottom)................................. 5.0 + 1506 (bottom)..............,.................. 4.0 + +The temperature, therefore, diminishes with increasing depth to about +700 or 800 feet, and below this remains sensibly the same down to 1,506 +feet; or in other words, a constant temperature of 4° C. prevails at all +depths below about. 820 feet. This is in accordance with the theory, the +temperature named being that of the maximum density of water, and it +confirms the recent observations of Prof. Forel in Switzerland; he +found, for example, that a constant temperature of 4° C. was reached in +Lake Zurich at a depth of nearly 400 feet, the lake being then covered +with 4 inches of ice. The explanation of the observed fact that Lake +Tahoe does not entirely freeze over even in severe winters is found in +the extreme depth; and the fact that the bodies of drowned persons do +not rise to the surface after the lapse of the usual time is explained +by the low temperature prevailing near the bottom, which does not allow +the necessary decomposition to go forward so as to produce the ordinary +result. + +The water of Lake Tahoe is remarkable both for its transparency and +beauty of color. A series of observations made at the close of August or +beginning of September showed that a horizontally adjusted dinner plate +of about 9½ inches diameter was visible at noon at a depth of 108 feet. +The maximum depth of the limit of visibility as found by Prof. Forel, in +Lake Geneva, was 56 feet. He showed, moreover, that this limit is much +greater in. winter than in summer, as explained in part by the greater +absence of suspended matter and in part by the fact that increase of +temperature increases the absorbing power of water for light. The +maximum depth of visibility in the Atlantic Ocean, as found by Count +de Pourtales, was 162 feet, and Prof. Le Conte states his belief that +winter observations in Lake Tahoe would place the limit at even a +greater depth than this. The author gives a detailed and interesting +discussion in regard to the blue color of lake waters, reviewing in full +the results of previous writers on the subject, and concludes that while +pure water unquestionably absorbs a larger part of the red end of the +spectrum, and hence appears blue by transmitted light, the color seen by +diffuse reflection is mainly due to the selective reflection from the +fine particles suspended in it. + +The last subject discussed by the author is that of the rhythmical +variations of level, or "seiches," of deep lakes; he applies the usual +formula to Lake Tahoe, and calculates from it the length of a complete +longitudinal and of a transverse "seiche;" these are found to be +eighteen or nineteen minutes in the first case and thirteen minutes in +the second. + + * * * * * + +A catalogue, containing brief notices of many important scientific +papers heretofore published in the SUPPLEMENT, may be had gratis at this +office. + + * * * * * + + + + +THE SCIENTIFIC AMERICAN SUPPLEMENT. + +PUBLISHED WEEKLY. + +TERMS OF SUBSCRIPTION, $5 A YEAR. + + +Sent by mail, postage prepaid, to subscribers in any part of the United +States or Canada. 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Hart was the originator of the Project Gutenberg-tm +concept of a library of electronic works that could be freely shared +with anyone. For forty years, he produced and distributed Project +Gutenberg-tm eBooks with only a loose network of volunteer support. + +Project Gutenberg-tm eBooks are often created from several printed +editions, all of which are confirmed as Public Domain in the U.S. +unless a copyright notice is included. Thus, we do not necessarily +keep eBooks in compliance with any particular paper edition. + +Most people start at our Web site which has the main PG search facility: + + www.gutenberg.org + +This Web site includes information about Project Gutenberg-tm, +including how to make donations to the Project Gutenberg Literary +Archive Foundation, how to help produce our new eBooks, and how to +subscribe to our email newsletter to hear about new eBooks. diff --git a/9076-8.zip b/9076-8.zip Binary files differnew file mode 100644 index 0000000..8ce29fa --- /dev/null +++ b/9076-8.zip diff --git a/9076-h.zip b/9076-h.zip Binary files differnew file mode 100644 index 0000000..c9a8654 --- /dev/null +++ b/9076-h.zip diff --git a/9076-h/9076-h.htm b/9076-h/9076-h.htm new file mode 100644 index 0000000..b1dc0aa --- /dev/null +++ b/9076-h/9076-h.htm @@ -0,0 +1,4645 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> +<html> +<head> +<meta name="generator" content="HTML Tidy, see www.w3.org"> +<meta http-equiv="Content-Type" content= +"text/html; charset=ISO-8859-1"> +<title>The Project Gutenberg eBook of Scientific American +Supplement, April 19, 1884</title> +<style type="text/css"> +<!-- +body {margin-left: 15%; margin-right: 15%; background-color: white} +img {border: 0;} +h1,h2,h3 {text-align: center;} +.ind {margin-left: 10%; margin-right: 10%;} +hr {text-align: center; width: 50%;} +.ctr {text-align: center;} +--> +</style> +</head> +<body> + + +<pre> + +The Project Gutenberg EBook of Scientific American Supplement, No. 433, +April 19, 1884, by Various + +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: Scientific American Supplement, No. 433, April 19, 1884 + +Author: Various + +Posting Date: October 10, 2012 [EBook #9076] +Release Date: October, 2005 +First Posted: September 3, 2003 + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN SUPPL., NO. 433 *** + + + + +Produced by J. Niehof, D. Kretz, J. Sutherland, and +Distributed Proofreaders + + + + + + +</pre> + + +<p class="ctr"><a href="images/1a.png"><img src= +"images/1a_th.jpg" alt=""></a></p> + +<h1>SCIENTIFIC AMERICAN SUPPLEMENT NO. 433</h1> + +<h2>NEW YORK, APRIL 19, 1884</h2> + +<h4>Scientific American Supplement. Vol. XVII, No. 433.</h4> + +<h4>Scientific American established 1845</h4> + +<h4>Scientific American Supplement, $5 a year.</h4> + +<h4>Scientific American and Supplement, $7 a year.</h4> + +<hr> +<table summary="Contents" border="0" cellspacing="5"> +<tr> +<th colspan="2">TABLE OF CONTENTS.</th> +</tr> + +<tr> +<td valign="top">I.</td> +<td><a href="#1">CHEMISTRY, METALLURGY, ETC.--New Analogy between +Solids, Liquids, and Gases.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#2">Hydrogen Amalgam.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#3">Treatment of Ores by Electrolysis.--By M. +KILIANI.</a></td> +</tr> + +<tr> +<td valign="top">II.</td> +<td><a href="#4">ENGINEERING, AND MECHANICS.--Electric Railway at +Vienna.--With engraving.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#5">Instruction in Mechanical Engineering.--Technical +and trade education.--A course of study sketched out.--By Prof. +R.H. THURSTON.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#6">Improved Double Boiler.--3 figures.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#7">The Gardner Machine Gun.--With three engravings +showing the single barrel, two barrel, and five barrel +guns.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#8">Climbing Tricycles.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#9">Submarine Explorations.--Voyage of the +Talisman.--The Thibaudier sounding apparatus.--With map, diagrams, +and engravings.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#10">Jamieson's Cable Grapnel.--With +engraving.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#11">A Threaded Set Collar.</a></td> +</tr> + +<tr> +<td valign="top">III.</td> +<td><a href="#12">TECHNOLOGY.--Wretched Boiler Making.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#13">Pneumatic Malting.--With full description of the +most improved methods and apparatus.--Numerous figures.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#14">Reducing and Enlarging Plaster Casts.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#15">Stripping the Film from Gelatine +Negatives.</a></td> +</tr> + +<tr> +<td valign="top">IV.</td> +<td><a href="#16">ELECTRICITY.--Non-sparking Key.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#17">New Instruments for Measuring Electric Currents +and Electromotive Force.--By MESSRS. K.E. CROMPTON and GISBERT +KAPP.--Paper read before the Society of Telegraph Engineers.--With +several engravings.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#18">When Does the Electric Shock Become +Fatal?</a></td> +</tr> + +<tr> +<td valign="top">V.</td> +<td><a href="#19">ART AND ARCHÆOLOGY.--Robert Cauer's Statute +of Lorelei.--With engraving.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#20">The Pyramids of Meroe.--With engraving.</a></td> +</tr> + +<tr> +<td valign="top">VI.</td> +<td><a href="#21">ASTRONOMY AND METEOROLOGY.--The Red Sky.--Cause +of the same explained by the Department of Meteorology.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#22">A Theory of Cometary Phenomena.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#23">On Comets.--By FURMAN LEAMING, M.D.</a></td> +</tr> + +<tr> +<td valign="top">VII.</td> +<td><a href="#24">NATURAL HISTORY.--The Prolificness of the +Oyster.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#25">Coarse Food for Pigs.</a></td> +</tr> + +<tr> +<td valign="top">VIII.</td> +<td><a href="#26">BOTANY, HORTICULTURE, ETC.--Forms of Ivy.--With +several engravings.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#27">Propagating Roses.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#28">A Few of the Best Inulas.--With +engraving.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#29">Fruit Growing.--By P.H. FOSTER.</a></td> +</tr> + +<tr> +<td valign="top">IX.</td> +<td><a href="#30">MEDICINE, HYGIENE, ETC.--A People without +Consumption, and Some Account of Their Country, the Cumberland +Tableland. --By E.M. WIGHT.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#31">The Treatment of Habitual Constipation.</a></td> +</tr> + +<tr> +<td valign="top">X.</td> +<td><a href="#32">MISCELLANEOUS.--The French Scientific Station at +Cape Horn.</a></td> +</tr> + +<tr> +<td valign="top">XI.</td> +<td><a href="#33">BIOGRAPHY.--The Late Maori Chief, Mete +Kingi.--With portrait.</a></td> +</tr> +</table> + +<hr> +<p><a name="32"></a></p> + +<h2>THE FRENCH SCIENTIFIC STATION AT CAPE HORN.</h2> + +<p>In 1875 Lieutenant Weyprecht of the Austrian navy called the +attention of scientific men to the desirability of having an +organized and continual system of hourly meteorological and +magnetic observations around the poles. In 1879 the first +conference of what was termed the International Polar Congress was +held at Hamburg. Delegates from eight nations were +present--Germany, Austria, Denmark, France, Holland, Norway, +Russia, and Sweden.</p> + +<p>The congress then settled upon a programme whose features were: +1. To establish general principles and fixed laws in regard to the +pressure of the atmosphere, the distribution and variation of +temperature, atmospheric currents, climatic characteristics. 2. To +assist the prediction of the course and occurrence of storms. 3. To +assist the study of the disturbances of the magnetic elements and +their relations to the auroral light and sun spots. 4. To study the +distribution of the magnetic force and its secular and other +changes. 5. To study the distribution of heat and submarine +currents in the polar regions. 6. To obtain certain dimensions in +accord with recent methods. Finally, to collect observations and +specimens in the domain of zoology, botany, geology, etc.</p> + +<p>The representatives of the various nations had several +conferences later, and by the 1st of May, 1881, there were +sufficient subscribers to justify the establishment of eight Arctic +stations.</p> + +<p>France entered actively in this work later, and its first +expedition was to Orange Bay and Cape Horn, under the surveillance +and direction of the Academy of Sciences, Paris, and responsible to +the Secretary of the Navy. On the 6th of September, 1882, this +scientific corps established itself in Orange Bay, near Cape Horn, +and energetically began its serious labors, and by October 22 the +greater part of their preliminary preparations was completed, +comprising the erection of a magnetic observatory, an astronomic +observatory, a room for the determination of the carbonic anhydride +of the air, another for the sea register, and a bridge 92 feet +long, photographic laboratory, barometer room, and buildings for +the men, food, and appurtenances, together with a laboratory of +natural history.</p> + +<p>In short, in spite of persistent rains and the difficulties of +the situation, from September 8 to October 22 they erected an +establishment of which the different parts, fastened, as it were, +to the flank of a steep hill, covered 450 square meters (4,823 +square feet), and rested upon 200 wooden piles.</p> + +<p>From September 26, 1882, to September 1, 1883, night and day +uninterruptedly, a watch was kept, in which the officers took part, +so that the observations might be regularly made and recorded. +Every four hours a series of direct magnetic and meteorological +observations was made, from hour to hour meteorological notes were +taken, the rise and fall of the sea recorded, and these were +frequently multiplied by observations every quarter of an hour; the +longitude and latitude were exactly determined, a number of +additions to the catalogue of the fixed stars for the southern +heavens made, and numerous specimens in natural history +collected.</p> + +<p>The apparatus employed by the expedition for the registration of +the magnetic elements was devised by M. Mascart, by which the +variations of the three elements are inscribed upon a sheet of +paper covered with gelatine bromide, inclination, vertical and +horizontal components, with a certainty which is shown by the 330 +diurnal curves brought back from the Cape.</p> + +<p>The register proper is composed of a clock and a photographic +frame which descends its entire length in twenty-four hours, thus +causing the sensitized paper to pass behind a horizontal window +upon which falls the light reflected by the mirrors of the magnetic +instruments. One of those mirrors is fixed, and gives a line of +reference; the other is attached to the magnetic bar, whose +slightest movements it reproduces upon the sensitized paper. The +moments when direct observations were taken were carefully +recorded. The magnetic <i>pavilion</i> was made of wood and copper, +placed at about fifty-three feet from the dwellings or camp, near +the sea, against a wooded hill which shaded it completely; the +interior was covered with felt upon all its sides, in order to +avoid as much as possible the varying temperatures.</p> + +<p>The diurnal amplitude of the declination increased uniformly +from the time of their arrival in September up to December, when it +obtained its maximum of 7'40", then diminished to June, when it is +no more than 2'20"; from this it increased up to the day of +departure. The maximum declination takes place toward 1 P.M., the +minimum at 8:50 A.M. The night maxima and minima are not clearly +shown except in the southern winter.</p> + +<p>The mean diurnal curve brings into prominence the constant +diminution of the declination and the much greater importance of +the perturbations during the summer months. These means, combined +with the 300 absolute determinations, give 4' as the annual change +of the declination.</p> + +<p>M. Mascart's apparatus proved to be wonderfully useful in +recording the rapid and slight perturbations of the magnet. +Comparisons between the magnetic and atmospheric perturbations gave +no result. There was, however, little stormy weather and no auroral +displays. This latter phenomenon, according to the English +missionaries, is rarely observed in Tierra del Fuego.</p> + +<p>The electrometer used at the Cape was founded upon the principle +developed by Sir William Thomson. The atmospheric electricity is +gathered up by means of a thin thread of water, which flows from a +large brass reservoir furnished with a metallic tube 6.5 feet long. +The reservoir is placed upon glass supports isolated by sulphuric +acid, and is connected to the electrometer by a thread of metal +which enters a glass vessel containing sulphuric acid; into the +same vessel enters a platinum wire coming from the aluminum needle. +Only 3,000 observations were given by the photographic register, +due to the fact that the instruments were not fully protected +against constant wet and cold.</p> + +<p>Besides these observations direct observations of the +magnetometer were made, and the absolute determination of the +elements of terrestrial magnetism attempted.</p> + +<p>On the 17th of November, 1882, a severe magnetic disturbance +occurred, lasting from 12 M. until 3 P.M., which in three hours +changed the declination 42'. The same perturbation was felt in +Europe, and the comparison of the observations in the two +hemispheres will prove instructive.</p> + +<hr> +<p><a name="4"></a></p> + +<h2>THE ELECTRIC RAILWAY AT VIENNA.</h2> + +<p>The total length of this railway, which extended from the +Eiskeller in the Schwimmschul-Allee to the northern entrance of the +Rotunda, was 1528.3 meters; the gauge was 1 meter, and 60 per cent. +of the length consisted of tangents, the remaining 40 per cent. +being mostly curves of 250 meters radius. The gradients, three in +number, were very small, averaging about 1:750.</p> + +<p>Two generating dynamos were used, which were coupled in parallel +circuit, but in such a manner that the difference of potential in +both machines remained the same at all times. This was accomplished +by the well known method of coupling introduced by Siemens and +Halske, in which the current of one machine excites the field of +the other.</p> + +<p>Although the railroad was not built with a view of obtaining a +high efficiency, an electro-motive force of only 150 volts being +used, a mechanical efficiency of 50 per cent. was nevertheless +obtained, both with one generator and one car with thirty +passengers, as well as with two generators and two cars with sixty +passengers; while with two generators and three cars (two of them +having motors) the same result was shown.</p> + +<p class="ctr"><a href="images/1b.png"><img src= +"images/1b_th.jpg" alt="THE ELECTRIC RAILWAY AT VIENNA."> +</a></p> + +<p class="ctr">THE ELECTRIC RAILWAY AT VIENNA.</p> + +<p>The curves obtained by the apparatus that recorded the current +showed very plainly the action within the machines when the cars +were started or set in motion; at first, the current rose rapidly +to a very high figure, and then declined gradually to a fixed +point, which corresponded to the regular rate of speed. The +tractive power, therefore, increases rapidly to a value far +exceeding the frictional resistances, but this surplus energy +serves to increase the velocity, and disappears as soon as a +uniform velocity is reached.</p> + +<p>The average speed, both with one and three cars, was 30 +kilometers per hour.--<i>Zeitsch. f. Elektrotechnik</i>.</p> + +<hr> +<p><a name="5"></a></p> + +<h2>INSTRUCTION IN MECHANICAL ENGINEERING.</h2> + +<h3>By Professor R. H. THURSTON.</h3> + +<p>The writer has often been asked by correspondents interested in +the matter of technical and trade education to outline a course of +instruction in mechanical engineering, such as would represent his +idea of a tolerably complete system of preparation for entrance +into practice. The synopsis given at the end of this article was +prepared in the spring of 1871, when the writer was on duty at the +U.S. Naval Academy, as Assistant Professor of Natural and +Experimental Philosophy, and, being printed, was submitted to +nearly all of the then leading mechanical engineers of the United +States, for criticism, and with a request that they would suggest +such alterations and improvements as might seem to them best. The +result was general approval of the course, substantially as here +written. This outline was soon after proposed as a basis for the +course of instruction adopted at the Stevens Institute of +Technology, at Hoboken, to which institution the writer was at +about that time called. He takes pleasure in accepting a suggestion +that its publication in the SCIENTIFIC AMERICAN would be of some +advantage to many who are interested in the subject.</p> + +<p>The course here sketched, as will be evident on examination, +includes not only the usual preparatory studies pursued in schools +of mechanical engineering, but also advanced courses, such as can +only be taught in special schools, and only there when an unusual +amount of time can be given to the professional branches, or when +post graduate courses can be given supplementary to the general +course. The complete course, as here planned, is not taught in any +existing school, so far as the writer is aware. In his own lecture +room the principal subjects, and especially those of the first part +of the work, are presented with tolerable thoroughness; but many of +the less essential portions are necessarily greatly abridged. As +time can be found for the extension of the course, and as students +come forward better prepared for their work, the earlier part of +the subject is more and more completely developed, and the advanced +portions are taken up in greater and greater detail, each year +giving opportunity to advance beyond the limits set during the +preceding year.</p> + +<p>Some parts of this scheme are evidently introductory to advanced +courses of study which are to be taken up by specialists, each one +being adapted to the special instruction of a class of students +who, while pursuing it, do not usually take up the other and +parallel courses. Thus, a course of instruction in Railroad +Engineering, a course in Marine Engineering, or a course of study +in the engineering of textile manufactures, may be arranged to +follow the general course, and the student will enter upon one or +another of these advanced courses as his talents, interests, or +personal inclinations may dictate. At the Stevens Institute of +Technology, two such courses--Electrical and Marine +Engineering--are now organized as supplementary of the general +course, and are pursued by all students taking the degree of +Mechanical Engineer. These courses, as there given, however, are +not fairly representative of the idea of the writer, as above +expressed, since the time available in general course is far too +limited to permit them to be developed beyond the elements, or to +be made, in the true sense of the term, advanced professional +courses. Such advanced courses as the writer has proposed must be +far more extended, and should occupy the whole attention of the +student for the time. Such courses should be given in separate +departments under the direction of a General Director of the +professional courses, who should be competent to determine the +extent of each, and to prevent the encroachment of the one upon +another; but they should each be under the immediate charge of a +specialist capable of giving instruction in the branch assigned to +him, in both the theoretical and purely scientific, and the +practical and constructive sides of the work. Every such school +should be organized in such a manner that one mind, familiar with +the theory and the practice of the professional branches taught, +should be charged with the duty of giving general direction to the +policy of the institution and of directing the several lines of +work confided to specialists in the different departments. It is +only by careful and complete organization in this, as in every +business, that the best work can be done at least expense in time +and capital.</p> + +<p>In this course of instruction in Mechanical Engineering it will +be observed that the writer has incorporated the scheme of a +workshop course. This is done, not at all with the idea that a +school of mechanical engineering is to be regarded as a "trade +school," but that every engineer should have some acquaintance with +the tools and the methods of work upon which the success of his own +work is so largely dependent. If the mechanical engineer can +acquire such knowledge in the more complete course of instruction +of the trade school, either before or after his attendance at the +technical school, it will be greatly to his advantage. The +technical school has, however, a distinct field; and its province +is not to be confounded with that of the trade school. The former +is devoted to instruction in the theory and practice of a +profession which calls for service upon the men from the +latter--which makes demand upon a hundred trades--in the +prosecution of its designs. The latter teaches, simply, the +practical methods of either of the trades subsidiary to the several +branches of engineering, with only so much of science as is +essential to the intelligent use of the tools and the successful +application of the methods of work of the trade taught. The +distinction between the two departments of education, both of which +are of comparatively modern date, is not always appreciated in the +United States, although always observed in those countries of +Europe in which technical and trade education have been longest +pursued as essential branches of popular instruction. Throughout +France and Germany, every large town has its trade schools, in +which the trades most generally pursued in the place are +systematically taught; and every large city has its technical +school, in which the several professions allied to engineering are +studied with special development of those to which the conditions +prevailing at the place give most prominence and local +importance.</p> + +<p>A course of trade instruction, as the writer would organize it, +would consist, first, in the teaching of the apprentice the use of +the tools of his trade, the nature of its materials, and the +construction and operation of the machinery employed in its +prosecution. He would next be taught how to shape the simpler +geometrical forms in the materials of his trade, getting out a +straight prism, a cylinder, a pyramid, or a sphere, of such size +and form as may be convenient; getting lines and planes at right +angles, or working to miter; practicing the working of his "job" to +definite size, and to the forms given by drawings, which drawings +should be made by the apprentice himself. When he is able to do +good work of this kind, he should attempt larger work, and the +construction of parts of structures involving exact fitting and +special manipulations. The course, finally, should conclude with +exercises in the construction and erection of complete structures +and in the making of peculiar details, such as are regarded by the +average workman as remarkable "<i>tours de force</i>." The trade +school usually gives instruction in the common school branches of +education, and especially in drawing, free-hand and mechanical, +carrying them as far as the successful prosecution of the trade +requires. The higher mathematics, and advanced courses in physics +and chemistry, always taught in schools of engineering, are not +taught in the trade school, as a rule; although introduced into +those larger schools of this class in which the aim is to train +managers and proprietors, as well as workmen. This is done in many +European schools.</p> + +<p>As is seen above, the course of instruction in mechanical +engineering includes some trade education. The engineer is +dependent upon the machinist, the founder, the patternmaker, and +other workers at the trades, for the proper construction of the +machinery and structures designed by him. He is himself, in so far +as he is an engineer, a designer of constructions, not a +constructor. He often combines, however, the functions of the +engineer, the builder, the manufacturer, and the dealer, in his own +person. No man can carry on, successfully, any business in which he +is not at home in every detail, and in which he cannot instruct +every subordinate, and cannot show every person employed by him +precisely what is wanted, and how the desired result can be best +attained. The engineer must, therefore, learn, as soon and as +thoroughly as possible, enough of the details of every art and +trade, subsidiary to his own department of engineering, to enable +him to direct, with intelligence and confidence, every operation +that contributes to the success of his work. The school of +engineering should therefore be so organized that the young +engineer may be taught the elements of every trade which is likely +to find important application in his professional work. It cannot +be expected that time can be given him to make himself an expert +workman, or to acquire the special knowledge of details and the +thousand and one useful devices which are an important part of the +stock in trade of the skilled workman; but he may very quickly +learn enough to facilitate his own work greatly, and to enable him +to learn still more, with rapidity and ease, during his later +professional life. He must also, usually, learn the essential +elements and principles of each of several trades, and must study +their relations to his work, and the limitations of his methods of +design and construction which they always, to a greater or less +extent, cause by their own practical or economical limitations. He +will find that his designs, his methods of construction, and of +fitting up and erecting, must always be planned with an intelligent +regard to the exigencies of the shop, as well as to the aspect of +the commercial side of every operation. This extension of trade +education for the engineer into several trades, instead of its +restriction to a single trade, as is the case in the regular trade +school, still further limits the range of his instruction in each. +With unusual talent for manipulation, he may acquire considerable +knowledge of all the subsidiary trades in a wonderfully short space +of time, if he is carefully handled by his instructors, who must +evidently be experts, each in his own trade. Even the average man +who goes into such schools, following his natural bent, may do well +in the shop course, under good arrangements as to time and +character of instruction. If a man has not a natural inclination +for the business, and a natural aptitude for it, he will make a +great mistake if he goes into such a school with the hope of doing +creditable work, or of later attaining any desirable position in +the profession.</p> + +<p>The course of instruction, at the Stevens Institute of +Technology, includes instruction in the trades to the extent above +indicated. The original plan, as given below, included such a +course of trade education for the engineer; but it was not at once +introduced. The funds available from an endowment fund crippled by +the levying of an enormous "succession tax" by the United States +government and by the cost of needed apparatus and of unanticipated +expenses, in buildings and in organization, were insufficient to +permit the complete organization of this department. A few tools +were gathered together; but skilled mechanics could not be employed +to take up the work of instruction in the several courses. Little +could therefore be done for several years in this direction. In +1875 the writer organized a "mechanical laboratory," with the +purpose of attaining several very important objects: the +prosecution of scientific research in the various departments of +engineering work; the creation of an organization that should give +students an opportunity to learn the methods of research most +usefully employed in such investigations; the assistance of members +of the profession, and business organizations in the attempt to +solve such questions, involving scientific research, as are +continually arising in the course of business; the employment of +students who had done good work in their college course, when they +so desire, in work of investigation with a view to giving them such +knowledge of this peculiar line of work as should make them capable +of directing such operations elsewhere; and finally, but not least +important of all, to secure, by earning money in commercial work of +this kind, the funds needed to carry on those departments of the +course in engineering that had been, up to that time, less +thoroughly organized than seemed desirable. This "laboratory" was +organized in 1875, the funds needed being obtained by drawing upon +loans offered by friends of the movement and by the "Director."</p> + +<p>It was not until the year 1878, therefore, that it became +possible to attempt the organization of the shop course; and it was +then only by the writer assuming personal responsibility for its +expenses that the plan could be entered upon. As then organized--in +the autumn of 1878--a superintendent of the workshop had general +direction of the trade department of the school. He was instructed +to submit to the writer plans, in detail, for a regular course of +shop instruction, and was given as assistants a skilled mechanic of +unusual experience and ability, whose compensation was paid from +the mechanical laboratory funds, and guaranteed by the writer +personally, and another aid whose services were paid for partly by +the Institute and partly as above. The pay of the superintendent +was similarly assured. This scheme had been barely entered upon +when the illness of the writer compelled him to temporarily give up +his work, and the direction of the new organization fell into other +hands, although the department was carried on, as above, for a year +or more after this event occurred.</p> + +<p>The plan did not fall through; the course of instruction was +incorporated into the college course, and its success was finally +assured by the growth of the school and a corresponding growth of +its income, and, especially, by the liberality of President Morton, +who met expenses to the amount of many thousands of dollars by +drawing upon his own bank account. The department was by him +completely organized, with an energetic head, and needed support +was given in funds and by a force of skilled instructors. This +school is now in successful operation. This course now also +includes the systematic instruction of students in experimental +work, and the objects sought by the writer in the creation of a +"mechanical laboratory" are thus more fully attained than they +could have possibly been otherwise. It is to be hoped that, at some +future time, when the splendid bequest of Mr. Stevens may be +supplemented by gifts from other equally philanthropic and +intelligent friends of technical education, among the alumni of the +school and others, this germ of a trade school maybe developed into +a complete institution for instruction in the arts and trades of +engineering, and may thus be rendered vastly more useful by meeting +the great want, in this locality, of a real trade school, as well +as fill the requirements of the establishment of which it forms a +part, by giving such trade education as the engineer needs and can +get time to acquire.</p> + +<p>The establishment of advanced courses of special instruction in +the principal branches of mechanical engineering may, if properly +"dovetailed" into the organization, be made a means of somewhat +relieving the pressure that must be expected to be felt in the +attempt to carry out such a course as is outlined below. The +post-graduate or other special departments of instruction, in +which, for example, railroad engineering, marine engineering, and +the engineering of cotton, woolen, or silk manufactures, are to be +taught, may be so organized that some of the lectures of the +general course may be transferred to them, and the instructors in +the latter course thus relieved, while the subjects so taught, +being treated by specialists, may be developed more efficiently and +more economically.</p> + +<p>Outlines of these advanced courses, as well as of the courses in +trade instruction comprehended in the full scheme of mechanical +engineering courses laid out by the writer a dozen years ago, and +as since recast, might be here given, but their presentation would +occupy too much space, and they are for the present omitted.</p> + +<p>The course of instruction in this branch of engineering, at the +Stevens Institute of Technology, is supplemented by "Inspection +Tours," which are undertaken by the graduating class toward the +close of the last year, under the guidance of their instructors, in +which expeditions they make the round of the leading shops in the +country, within a radius of several hundred miles, often, and thus +get an idea of what is meant by real business, and obtain some +notion of the extent of the field of work into which they are about +to enter, as well as of the importance of that work and the +standing of their profession among the others of the learned +professions with which that of engineering has now come to be +classed.</p> + +<p>At the close of the course of instruction, as originally +proposed, and as now carried out, the student prepares a +"graduating thesis," in which he is expected to show good evidence +that he has profited well by the opportunities which have been +given him to secure a good professional education. These theses are +papers of, usually, considerable extent, and are written upon +subjects chosen by the student himself, either with or without +consultation with the instructor. The most valuable of these +productions are those which present the results of original +investigations of problems arising in practice or scientific +research in lines bearing upon the work of the engineer. In many +cases, the work thus done has been found to be of very great value, +supplying information greatly needed in certain departments, and +which had previously been entirely wanting, or only partially and +unsatisfactorily given by authorities. Other theses of great value +present a systematic outline of existing knowledge of some subject +which had never before been brought into useful form, or made in +any way accessible to the practitioner. In nearly all cases, the +student is led to make the investigation by the bent of his own +mind, or by the desire to do work that may be of service to him in +the practice of his profession. All theses are expected to be made +complete and satisfactory to the head of department of Engineering +before his signature is appended to the diploma which is finally +issued to the graduating student. These preliminaries being +completed, and the examinations having been reported as in all +respects satisfactory, the degree of Mechanical Engineer is +conferred upon the aspirant, and he is thus formally inducted into +the ranks of the profession.</p> + +<h3>COURSE OF INSTRUCTION IN MECHANICAL ENGINEERING.</h3> + +<h3>Robert H. Thurston--July, 1871.</h3> + +<p>I.</p> + +<p>MATERIALS USED IN ENGINEERING.--Classification, Origin, and +Preparation (where not given in course of Technical Chemistry), +Uses, Cost.</p> + +<p><i>Strength and Elasticity</i>.--Theory (with experimental +illustrations), reviewed, and tensile, transverse and torsional +resistance determined.</p> + +<p><i>Forms</i> of greatest strength determined. <i>Testing</i> +materials.</p> + +<p><i>Applications</i>.--Foundations, Framing in wood and +metal.</p> + +<p>FRICTION.--Discussion from Rational Mechanics, reviewed and +extended.</p> + +<p><i>Lubricants</i> treated with materials above.</p> + +<p>Experimental determination of "coefficients of friction."</p> + +<p>II.</p> + +<p>TOOLS.--Forms for working wood and metals. Principles involved +in their use.</p> + +<p>Principles of pattern making, moulding, smith and machinists' +work so far as they modify design.</p> + +<p>Exercises in Workshops in mechanical manipulation.</p> + +<p>Estimates of <i>cost</i> (stock and labor).</p> + +<p>MACHINERY AND MILL WORK.--Theory of machines. Construction. +Kinematics applied. Stresses, calculated and traced. Work of +machines. Selection of materials for the several parts. +Determination of <i>proportions</i> of details, and of <i>forms</i> +as modified by difficulties of construction.</p> + +<p>Regulators, Dynamometers, Pneumatic and Hydraulic machinery. +Determining <i>moduli</i> of machines.</p> + +<p>POWER, transmission by gearing, belting, water, compressed air, +etc.</p> + +<p>LOADS, transportation.</p> + +<p>III.</p> + +<p>HISTORY AND PRESENT FORMS OF THE PRIME MOVERS.</p> + +<p><i>Windmills</i>, their theory, construction, and +application.</p> + +<p><i>Water Wheels</i>. Theory, construction, application, testing, +and comparison of principal types.</p> + +<p><i>Air, Gas, and Electric Engines</i>, similarly treated.</p> + +<p>STEAM ENGINES.--Classification. [Marine (merchant) Engine +assumed as representative type.] Theory. Construction, including +general design, form and proportion of details.</p> + +<p><i>Boilers</i> similarly considered. Estimates of +<i>cost</i>.</p> + +<p><i>Comparison</i> of principal types of Engines and Boilers. +Management and repairing. Testing and recording performance.</p> + +<p>IV.</p> + +<p>MOTORS APPLIED to Mills. Estimation of required power and of +<i>cost</i>.</p> + +<p>Railroads. Study of Railroad machinery.</p> + +<p>Ships. Structure of Iron Ships and rudiments of Naval +architecture and Ship propulsion.</p> + +<p>PLANNING Machine shops, Boiler shops, Foundries, and +manufactories of textile fabrics. Estimating <i>cost</i>.</p> + +<p>LECTURES BY EXPERTS.</p> + +<p>GENERAL SUMMARY of principal facts, and natural laws, upon the +thorough knowledge of which successful practice is based; and +general <i>resume</i> of principles of business which must be +familiar to the practicing engineer.</p> + +<p>V.</p> + +<p>GRADUATING THESES.</p> + +<p>GRADUATION.</p> + +<p>Accompanying the above are courses of instruction in higher +mathematics, graphics, physics, chemistry, and the modern languages +and literatures.</p> + +<hr> +<p><a name="6"></a></p> + +<h2>IMPROVED DOUBLE BOILER.</h2> + +<p>The operation of boiling substances under pressure with more or +less dilute sulphuric or sulphurous acid forms a necessary stage of +several important manufactures, such as the production of paper +from wood, the extraction of sugar, etc. A serious difficulty +attending this process arises from the destructive action of the +acid upon the boiler or chamber in which the operation is carried +on, and as this vessel, which is generally of large dimensions, is +exposed to considerable pressures, it is necessarily constructed of +iron or some other sufficiently resisting metal. An ingenious +method of avoiding this difficulty has been devised, we believe in +Germany, and has been put into practice with a certain amount of +success. It consists in lining the iron boiler with a covering of +lead, caused by fusion to unite firmly to the walls of the boiler, +and thus to protect it from the action of the acid. No trouble, it +is stated, is found to arise from the difference in expansion of +the two metals, which, moreover, adhere fairly well; but, on the +other hand, we believe it does actually occur that the repairs to +this lead lining are numerous, tedious, and costly of execution, so +that the system can scarcely be regarded as meeting the +requirements of the manufacturer. It is to secure all the +advantages possessed by a lead-lined vessel, without the drawback +of frequent and expensive repairs, that the digester, of which we +annex illustrations, has been devised by Mr. George Knowles, of +Billiter House, Billiter Street. It consists of a closed iron +cylindrical vessel suitable for boiling under pressure, and +containing a second vessel open at the top, and of such a diameter +as to leave an annular space between it and the walls of the outer +shell. This inner receiver, which may be made of lead, glass, +pottery, or any other suitable material, contains the substance to +be treated and the sulphurous acid or other solution in which it is +to be boiled. The annular space between the two vessels is filled +with water to the same level as the solution in the receiver, and +the latter is provided with suitable pipes or coils, in which steam +is caused to circulate for the purpose of raising the solution of +the desired temperature, and effecting the digesting process. At +the same time any steam generated collects in the upper part of the +boiler, and maintains an equal pressure within the whole apparatus. +Figs. 1 to 3 show the arrangement clearly. Within the boiler, a, is +placed the receiver, b, of pottery, lead, or other material, +leaving an annular space between it and the boiler; this space is +filled with water. The receiver, b, is furnished with a series of +pipes, in which steam or hot water circulates, to heat the charge +to the desired temperature. These pipes may be arranged either in +coils, as shown at d, Fig. 1, or vertically at d, Fig. 3. The +latter are provided with inner return pipes, so that any condensed +water accumulating at the bottom may be forced up the inner pipes +by the steam pressure and escape at the top. The vessel is charged +through the manhole, e, and the hopper, c, provided with a +perforated cover, and is discharged at the bottom by the valve, f, +shown in Figs. 2 and 3. The upper part of the boiler serves as a +steam dome, and the pressure on the liquid in the receiver and on +the water in the annular space is thereby maintained uniform. The +necessary fittings for showing the pressure in the vessel, water +level indicator, safety valve, cocks for testing solutions, etc., +are of course added to the apparatus, but are not indicated in the +drawing. The arrangement appears to us to possess considerable +merit, and we shall refer to it again on another occasion, after +experiments have been made to test its +efficiency.--<i>Engineering</i>.</p> + +<p class="ctr"><a href="images/3a.png"><img src= +"images/3a_th.jpg" alt="IMPROVED DOUBLE BOILER."></a></p> + +<p class="ctr">IMPROVED DOUBLE BOILER.</p> + +<hr> +<p><a name="7"></a></p> + +<h2>THE GARDNER MACHINE GUN.</h2> + +<p class="ctr"><img src="images/3b.png" alt= +"FIG. 1.--SINGLE BARREL GARDNER MACHINE GUN."></p> + +<p class="ctr">FIG. 1.--SINGLE BARREL GARDNER MACHINE GUN.</p> + +<p>The mechanism by which the various functions of loading, firing, +and extracting are performed is contained in a rectangular gun +metal case, varying in dimensions with the number of barrels in the +arm. In the single barrel gun the size of this case is 14 inches in +length, 5½ inches in depth, and 2½ inches in width. +The top of the box is hinged, so that easy access can be had to the +mechanism, which consists of a lock, the cartridge carrier, and the +devices for actuating them. In the multiple barrel guns, the frames +which, with the transverse bar at the end, hold the barrels in +place, form the sides of the mechanism chamber, in the front end of +which the barrels are screwed. The mechanism is actuated by a cam +shaft worked by a hand crank on one side of the chamber. By this +means the locks are driven backward and forward, the latter motion +forcing the cartridges into place, and the former withdrawing the +empty cartridge case after firing. The extractor hook pivoted to +the lock plunger rises, as the lock advances, over the rim of the +case, but is rigid as the lock is withdrawn, so that the action is +a positive one. The cartridges, which are contained in a suitable +frame attached to the forward part of the breech chamber, pass +through openings in the top plate of the latter, an efficient +distribution being secured by means of a valve having a transverse +motion. Each cartridge as it falls is brought into the axis of the +barrel and the plunger, while the advance motion of the lock forces +them into position. In the five-barrel gun illustrated by Fig. 3 +the cartridge feeder contains 100 cartridges, in five Vertical rows +of 20 cartridges each, and these are kept supplied, when firing, +from supplementary holders. Fig. 1 shows the portable rest +manufactured by the Gardner Gun Company. It consists of two wrought +iron tubes, placed at right angles to each other; the front bar can +be easily unlocked, and placed in line with the trail bar, from +which project two arms, each provided with a screw that serves for +the lateral adjustment of the gun. These screws are so arranged as +to allow for an oscillating motion of the gun through any distance +up to 15 deg. The tripod mounting, used for naval as well as land +purposes, is shown in Fig. 2, which illustrates the two barrel gun +complete. The five barrel gun, Fig. 3, is shown mounted on a +similar tripod. The length of this weapon over all is 53.5 inches, +the barrels (Henry system) are 33 inches long, with seven grooves +of a uniform twist of one turn in 22 inches.</p> + +<p class="ctr"><img src="images/3c.png" alt= +"Fig. 2.--TWO BARREL GARDNER GUN."></p> + +<p class="ctr">Fig. 2.--TWO BARREL GARDNER GUN.</p> + +<p>Gardener's five barrel gun in the course of one of the trials +fired 16,754 rounds with only 24 jams, and in rapid firing reached +a maximum of 330 shots in 30 seconds. The two barrel gun fired +6,929 rounds without any jam; the last 3,000 being in 11 minutes 39 +seconds, without any cleaning or oiling.--<i>Engineering</i>.</p> + +<p class="ctr"><img src="images/3d.png" alt= +"Fig. 3.--FIVE BARREL GARDNER GUN."></p> + +<p class="ctr">Fig. 3.--FIVE BARREL GARDNER GUN.</p> + +<hr> +<p><a name="8"></a></p> + +<h2>CLIMBING TRICYCLES.</h2> + +<p>The cycle trade is one which has been developed with great +rapidity within the last ten years, and, like all new industries, +has called forth a considerable amount of ingenuity and skill on +the part of those engaged in it. We cannot help thinking, however, +that much of this ingenuity has been misplaced, and that instead of +striving after new forms involving considerable complication and +weight, it would have been better and more profitable if +manufacturers had moderated their aspirations, and aimed at greater +simplicity of design; for it must be remembered that cyclists are, +as a rule, without the slightest mechanical knowledge, while the +machines themselves are subject to very hard usage and considerable +wear and tear in traveling over the ordinary roads in this country. +We refer, of course, more especially to tricycles, which in one +form or another are fast taking the place of bicycles, and which +promise to assume an important position in every day locomotion. +Hitherto one of the chief objections to the use of the tricycle has +been the great difficulty experienced in climbing hills, a very +slight ascent being sufficient to tax the powers of the rider to +such an extent as to induce if not compel him in most instances to +dismount and wheel his machine along by hand until more favorable +ground is reached. To obviate this inconvenience many makers have +introduced some arrangement of gearing speeds of two powers giving +the necessary variation for traveling up hill and on the level. We +noticed, however, one machine at the exhibition which seemed to +give all that could be desired without any gearing or chains at +all. This was a direct action tricycle shown by the National Cycle +Company, of Coventry, in which the pressure from the foot is made +to bear directly upon the main axle, and so transmitted without +loss to the driving wheels on each side, the position of the rider +being arranged so that just sufficient load is allowed to fall on +the back wheel as to obtain certainty in steerage. The weight of +this machine is much less than when gearing is used, and the +friction is also considerably reduced, trials with the dynamometer +having shown that on a level, smooth road, a pull of 1 lb. readily +moved it, while with a rider in the seat 4 lb. was sufficient. On +this tricycle any ordinary hill can, it is stated, be ascended with +great ease, and as a proof of its power it was exhibited at the +Stanley show climbing over a piece of wood 8 in. high, without any +momentum whatever. We understand that at the works at Coventry a +flight of stairs has been erected, and that no difficulty is +experienced in ascending them on one of these machines.--<i>The +Engineer</i>.</p> + +<hr> +<p><a name="9"></a></p> + +<h2>SUBMARINE EXPLORATIONS.</h2> + +<h3>VOYAGE OF THE TALISMAN.</h3> + +<p>It was but a few years ago that the idea was prevalent that the +seas at great depths were immense solitudes where life exhibited +itself under no form, and where an eternal night reigned. To-day, +thanks to expeditions undertaken for the purpose of exploring the +abysses of the ocean, we know that life manifests itself abundantly +over the bottom, and that at a depth of five and six thousand +meters light is distributed by innumerable phosphorescent animals. +Different nations have endeavored to rival each other in the effort +to effect these important discoveries, and several scientific +missions have been sent to different points of the globe by the +English and American governments. The French likewise have entered +with enthusiasm upon this new line of research, and for four +consecutive years, thanks to the devoted aid of the ministry of the +marine, savants have been enabled to take passage in government +vessels that were especially arranged for making submarine +explorations.</p> + +<p class="ctr"><a href="images/4a.png"><img src= +"images/4a_th.jpg" alt= +"THE FRENCH SCIENTIFIC STEAMER TALISMAN."></a></p> + +<p class="ctr">THE FRENCH SCIENTIFIC STEAMER TALISMAN.</p> + +<p>The first French exploration, which was an experimental trip, +was made in 1880 by the Travailleur in the Gulf of Gascogne. Its +unhoped for results had so great an importance that the following +year the government decided to continue its researches, and the +Travailleur was again put at the disposal of Mr. Alph. Milne +Edwards and the commission over which he presided. Mr. Edwards +traversed the Gulf of Gascogne, visited the coast of Portugal, +crossed the Strait of Gibraltar, and explored a great portion of +the Mediterranean. In 1882 the same vessel undertook a third +mission to the Atlantic Ocean, and as far as to the Canary Islands. +The Travailleur, however, being a side-wheel advice-boat designed +for doing service at the port of Rochefort, presented none of those +qualities that are requisite for performing voyages that are +necessarily of long duration. The quantity of coal that could be +stored away in her bunkers was consumed in a week, and, after that, +she could not sail far from the points where it was possible for +her to coal up again. So after her return Mr. Edwards made a +request for a ship that was larger, a good sailer, and that was +capable of carrying with it a sufficient supply of fuel for +remaining a long time at sea, and that was adapted to submarine +researches. The Commission indorsed this application, and the +Minister of Instruction received it and transmitted it to Admiral +Jauréguiberry--the Minister of the Marine--who at once gave +orders that the Talisman should be fitted up and put in commission +for the new dredging expedition. This vessel, under command of +Captain Parfait, who the preceding year had occupied the same +position on the Travailleur, left the port of Rochefort on the 1st +of June, 1883, having on board Mr. Milne Edwards and the scientific +commission that had been appointed by the Minister of Public +Instruction. The Talisman explored the coasts of Portugal and +Morocco, visited the Canary and Cape Verd Islands, traversed the +Sea of Sargasso, and, after a stay of some time at the Azores, +returned to France, after exploring on its way the Gulf of Gascogne +(Fig.).</p> + +<p class="ctr"><img src="images/4b.png" alt= +"FIG.1.--CHART OF THE TALISMAN'S VOYAGE."></p> + +<p class="ctr">FIG.1.--CHART OF THE TALISMAN'S VOYAGE.</p> + +<p>The magnificent collections in natural history that were +collected on this cruise, and during those of preceding years made +by the Travailleur, are, in a few days, to be exhibited at the +Museum of Natural History. We think we shall be doing a service to +the readers of this journal, in giving them some details as to the +organization of the Talisman expedition as well as to the manner in +which the dredgings were performed.</p> + +<p class="ctr"><a href="images/4c.png"><img src= +"images/4c_th.jpg" alt="FIG.2.--PLAN OF THE VESSEL."> +</a></p> + +<p class="ctr">FIG.2.--PLAN OF THE VESSEL.</p> + +<p>The vessel, as shown by her plan in Fig. 2, had to undergo +important alterations for the cruise that she was to undertake. Her +deck was almost completely freed from artillery, since this would +have encumbered her too much. Immediately behind the bridge, in the +center of the vessel, there were placed two windlasses, one, A, to +the right, and the other, B, to the left (Fig. 2). These machines, +whose mode of operation will be explained further along, were to +serve for raising and lowering the fishing apparatus. A little +further back there were constructed two cabins, G and HH. The first +of these was designed to serve as a laboratory, and the second was +arranged as quarters for the members of the mission.</p> + +<p>The sounding apparatus, the Brothergood engine for actuating it, +and the electric light apparatus were placed upon the bridge. The +operating of the sounding line and of the electric light was +therefore entirely independent of that of the dredges. On the +foremast, at a height of about two meters, there was placed a +crane, F, which was capable of moving according to a horizontal +plane. Its apex, as may be seen from the plan of the boat, was +capable of projecting beyond the sides of the ship, to the left and +right. To this apex was fixed a pulley over which ran the cable +that supported the dredges or bag-nets, which latter were thus +carried over the boat's sides.</p> + +<p class="ctr"><a href="images/4d.png"><img src= +"images/4d_th.jpg" alt= +"FIG.3.--DIAGRAM OF THE THIBAUDIER SOUNDING APPARATUS."></a></p> + +<p class="ctr">FIG.3.--DIAGRAM OF THE THIBAUDIER SOUNDING +APPARATUS.</p> + +<p>The preliminary operation in every submarine exploration +consists in exactly determining the depth of the sea immediately +beneath the vessel. To effect this object different sounding +apparatus have been proposed. As the trials that were made of these +had shown that each of them possessed quite grave defects, Mr. +Thibaudier, an engineer of the navy, installed on board the +Talisman last year a new sounding apparatus which had been +constructed according to directions of his and which have given +results that are marvelous. The apparatus automatically registers +the number of meters of wire that is paid out, and as soon as the +sounding lead touches bottom, it at once stops of itself. This +apparatus is shown in Fig. 4, and a diagram of it is given in Fig. +3, so that its operation may be better understood. The Thibaudier +sounding apparatus consists of a pulley, P (Fig. 3), over which is +wound 10,000 meters of steel wire one millimeter in diameter. From +this pulley, the wire runs over a pulley, B, exactly one meter in +circumference; from thence it runs to a carriage, A, which is +movable along wooden shears, runs up over a fixed pulley, K, and +reaches the sounding lead, S, after traversing a guide, g, where +there is a small sheave upon which it can bear, whatever be the +inclination of the boat. The wheel, B, carries upon its axle an +endless screw that sets in motion two toothed wheels that indicate +the number of revolutions that it is making. One of these marks the +units and the other the hundredths (Fig. 5). This last is graduated +up to 10,000 meters. As every revolution of the wheel, B, +corresponds to one meter, the number indicated by the counter +represents the depth. Upon the axle of the winding pulley there is +a break pulley, p. The brake, f, is maneuvered by a lever, L, at +whose extremity there is a cord, C, which is made fast to the +carriage, A. When, during the motions due to rolling, the tension +of the steel wire that supports the lead diminishes or increases, +the carriage slightly rises or falls, and, during these motions, +acts more or less upon the brake and consequently regulates the +velocity with which the wire unwinds. When the lead touches bottom, +the wire, being suddenly relieved from all weight (which is +sometimes as much as 70 kilos), instantly stops.</p> + +<p class="ctr"><a href="images/5b.png"><img src= +"images/5b_th.jpg" alt= +"FIG. 4.--GENERAL VIEW OF THE SOUNDING APPARATUS IN THE "></a></p> + +<p class="ctr">FIG. 4.--GERNERAL VIEW OF THE SOUNDING APPARATUS IN +THE "TALISMAN:"</p> + +<p>The maneuver of this apparatus may be readily understood. The +apparatus and its weights are arranged in the interior of the +vessel. A man bears upon the lever, L (Fig. 3), and the counter is +set at zero. All being thus arranged, the man lets go of the break, +and the unwinding then proceeds until the lead has touched bottom. +During the operation of sounding, the boat is kept immovable by +means of its engine, so that the wire shall remain as vertical as +possible. The bottom being reached, the unwinding suddenly ceases, +and there is nothing further to do but read the indication given by +the differential counter, this giving the depth.</p> + +<p class="ctr"><img src="images/5a.png" alt= +"FIG. 5.--APPARATUS FOR MEASURING THE LENGTH OF THE WIRE PAID OUT."> +</p> + +<p class="ctr">FIG. 5.--APPARATUS FOR MEASURING THE LENGTH OF THE +WIRE PAID OUT.</p> + +<p>Near the winding pulley, there is a small auxiliary engine, M, +which is then geared with the axle of the said pulley, and which +raises the sounding apparatus that has been freed from its weight +by a method that will be described further along.</p> + +<p>We have endeavored in Fig. 4 to show the aspect of the bridge at +the moment when a sounding was about being made. From this +engraving (made from a photograph) our readers may obtain a clear +idea of the Thibaudier sounding apparatus, and understand how the +wheel over which the wire runs is set in motion by the Brothergood +engine.--<i>La Nature</i>.</p> + +<hr> +<p><a name="10"></a></p> + +<h2>CABLE GRAPNEL.</h2> + +<p>Some improvements have recently been made by Mr. Alexander Glegg +and the inventor in the well-known Jamieson grapnel used for +raising submerged submarine cables. The chief feature of the +grapnel is that the flukes, being jointed at the socket, bend back +against a spring when they catch a rock, until the grapnel clears +the obstruction, but allow the cable to run home to the crutch +between the fluke and base, as shown in the figures. In the older +form the cable was liable to get jammed, and cut between the fixed +toe or fluke and the longer fluke jointed into it. This is now +avoided by embracing the short fluke within the longer one. The +shank, formerly screwed into the boss, is now pushed through and +kept up against the collar of the boss, by the volute spring, which +at the same time presses back the hinged flukes after being +displaced by a rock. The shank can now freely swivel round, whereas +before it was rigidly fixed. The toes or flukes are now made of +soft cast steel, which can be straightened if bent, and the boss is +made of cast steel or gun-metal.</p> + +<p class="ctr"><img src="images/5c.png" alt= +"JAMIESON'S GRAPNEL."></p> + +<p class="ctr">JAMIESON'S GRAPNEL.</p> + +<hr> +<p><a name="12"></a></p> + +<h2>WRETCHED BOILERMAKING.</h2> + +<p><i>To the Editor of the Scientific American</i>:</p> + +<p>As long as I have been a reader of the SCIENTIFIC AMERICAN I +have been pleased with the manner in which you investigate and +explain the cause of any boiler explosion which comes to your +knowledge; and I have rejoiced when you heaped merited censure upon +the fraudulent boilermaker. In your paper in December last you +copied a short article on "Conscience in Boilermaking," in which +the writer, after speaking of the tricks of the boilermaker in +using thinner iron for the center sheets than for the others, and +in "upsetting" the edges of the plates to make them appear thicker, +goes on to say: "We call attention to this, because the discovery +of such practice has made serious trouble between the boilermaker +and the steam user. We would not believe that there were men so +blind to the duties and obligations which rest upon them as to +resort to such practice, but the careful inspector finds all such +defects, and in time we come to know whose work is carefully and +honestly done, and whose is open to suspicion. In States and cities +where inspection laws are in force that give the methods and rules +by which the safe working pressure of a boiler is calculated, there +is no alternative except to follow the rules; and if certain +requirements regarding construction are a part of the law, there is +no authority or right to depart from it, and yet there are +boilermakers who try to force their boilers into such localities +when their work is not up to the requirements of the law."</p> + +<p>Now, if some boilermakers are so dishonest as to try and impose +upon the locomotive engineer, who they know will carefully examine +every part of his boiler, and who is able to detect any flaw, it is +not to be expected that the farmer will escape. Nor does he. The +great number of explosions of boilers used in thrashing and in +other farm work proves that there are boilermakers who "force their +boilers into such localities when their work is not up to the +requirements of the law." And the boilermaker, if he be dishonest, +is doubly tempted if the broad width of a continent intervenes +between him and the farmer for whom his work is intended, and if in +the place where the boiler is to be used there are no inspection +laws in force. The farmer who lives many miles from a city, and who +has no means of testing any boiler he may purchase, is wholly at +the mercy of the boilermaker, and must run it until it explodes or +time proves it to have been honestly made. Then, again, there are +boilermakers who, although making boilers of good iron and of the +proper thickness, finish them off so badly that the farmer is put +to great inconvenience and expense to put them in working order. +Two years ago I purchased a straw-burning engine and boiler made by +an Eastern firm. Before it had run ten days the boiler began to +leak at the saddle-bolt holes. The engineer tightened the nuts as +far as possible, but could not stop the leaks, which at last became +so bad that we had to stop work and take the engine to the shop. +Upon taking off the saddle and taking out the bolts it was +discovered that they were too small for the holes in the boiler, +and that they had been wrapped with candle wick and white lead to +make them fill the holes, and that a light washer had been put on +each bolt between the head and the inside of the boiler. This +washer kept the lead in its place, and prevented the boiler from +showing a leak when first fired up. The water pipes in the fire-box +soon gave out and became utterly useless. Upon inquiring of the +patentee of this straw-burning device, who was supposed to have put +it in my boiler, he stated that he had had nothing to do with it, +but that it was put in by the firm selling these engines, and "as +cheaply as possible." Before I got this boiler and engine in fair +running order I had spent hundreds of dollars and had to do +entirely away with the water grates.</p> + +<p>Last summer, needing another tharshing engine, I was induced to +buy one of the same make as my old one, but with a different +straw-burning device. The firm who sold it to me agreed that it +should have none of the faults of the old one. Well, I got it, and, +upon hauling it out to my ranch, and getting up steam, I found it +to be much worse than the first one I had bought. The boiler leaked +at nearly every hole where a tap had been screwed into it. It took +an engineer, a boilermaker, a blacksmith, and a fireman several +days to get it in shape so that we could use it at all; and after +we did start up, the boilermaker had to be sent for several times +to stop new leaks that were continually showing themselves.</p> + +<p>I send you by this mail for your inspection one of the saddle +bolts and one of the bolts taken out of the piston, and also the +certificates of the engineer, boilermaker, and machinist who +repaired the boiler. In justice to my fellow-farmers I ought to +publish these certificates and the names of these boilermakers to +the world, but, for the present at least, I refrain from so doing. +These boilermakers will see this article and they will know, if the +public does not, for whom it is intended. If it has the effect of +making them exercise more care in the construction and fitting up +of their engines and boilers, I have not written in vain.</p> + +<p>D. FREEMAN.</p> + +<p>Los Angeles, Cal., March 7,1884.</p> + +<p>[The two bolts and the certificates above referred to accompany +the letter of Mr. Freeman. We can only wonder how it was that, +after having been treated as he relates in the first instance, he +should have had any further business with parties who would send +out such boilers, for the testimony of the engineer and workmen +make the case even stronger than Mr. Freeman has put it.--ED.]</p> + +<hr> +<p><a name="11"></a></p> + +<h2>A THREADED SET COLLAR.</h2> + +<p>There are cases where a long screw must be rotated with a +traversing nut or other threaded piece traveling on its thread a +limited and variable distance. At one time the threaded nut or +piece may be required to go almost the entire length of the screw, +and at another time a much shorter traverse would be required. In +many instances the use of side check nuts is inconvenient, and in +some it is impossible. One way of utilizing the nut as a set collar +is to drill through its side for a set screw, place it on its +screw, pour a little melted Babbitt metal, or drop a short, cold +plug of it into the hole, tap the hole, and the tap will force the +Babbitt into the threads.</p> + +<p>Insert the set screw, and when it acts on the Babbitt metal it +will force it with great friction on to the thread without injuring +the thread; and when the set screw tension is released, the nut +turns freely. A similar and perhaps a better result may be obtained +by slotting the hole through the nut as though for the reception of +a key. Secure a key (preferably of the same material as the nut) by +slight upsetting at its ends, and then thread the nut, key, and +all. Place a set screw through the nut over the threaded key, and +the job is complete.</p> + +<hr> +<p><a name="13"></a></p> + +<h2>PNEUMATIC MALTING.</h2> + +<p>The lethargy in the malting trade, and in all matters relating +to malting processes, induced by two centuries of restrictive +legislation, is being gradually shaken off by the malting industry +under the new law. For many years nearly all improvements in +malting processes originated abroad, as numberless Acts of +Parliament fettered every process and the use of every implement +requisite in a malt-house in this country. The entire removal of +these legislative restrictions gives an opportunity for improved +processes, which promises to open up a considerable field for +engineering work, and to develop a very backward art by the +application of scientific principles. The present time is, +therefore, one of more material change than malting has ever +experienced.</p> + +<p class="ctr"><a href="images/6a.png"><img src= +"images/6a_th.jpg" alt= +"PNEUMATIC MALTING AT TROYES. Fig. 1."></a></p> + +<p class="ctr">PNEUMATIC MALTING AT TROYES. Fig. 1.</p> + +<p>Of the numerous improvements effected in the past few years, +those made by M. Galland in France, and more recently by M. +Saladin, are by far the most prominent. M. Galland originated what +is known as the pneumatic system eight or nine years ago. This +system is carried out at the Maxéville brewery, near +Nancy.</p> + +<p class="ctr"><a href="images/6b.png"><img src= +"images/6b_th.jpg" alt= +"PNEUMATIC MALTING AT TROYES. Fig. 2."></a></p> + +<p class="ctr">PNEUMATIC MALTING AT TROYES. Fig. 2.</p> + +<p>Since that time further improvements have been made by M. +Galland; but more recently great advances have been made in the +system by M. Saladin. He has developed the practice of the leading +principle, and in conjunction with Mr. H. Stopes, of London, has +added improved kilns and various mechanical apparatus for +performing the work previously done by hand. He has also devised a +very ingenious machine for cooling the moist air by which the +process is carried on.</p> + +<p class="ctr"><a href="images/7d.png"><img src= +"images/7d_th.jpg" alt= +"FIG. 4.--ECHANGEUR AND TURNING MACHINE."></a></p> + +<p class="ctr">FIG. 4.--ECHANGEUR AND TURNING MACHINE.</p> + +<p>At the recent Brewery Exhibition, some of the machinery used in +these new maltings was shown in action by Messrs. H. Stopes & +Co., together with drawings of a malting constructed at Troyes for +M. Bonnette under M. Saladin's instructions. This malting is the +third constructed for the same firm, the others being at Nancy. +That at Troyes we now illustrate. We will not occupy space by a +general description of the pneumatic system, one great feature in +which is the continuous manufacture of malt throughout the year +instead of only from five to eight months of the year, as it will +be gathered from the following description of the Troyes +malting:</p> + +<p class="ctr"><img src="images/6c.png" alt= +"FIG. 5.--ECHANGEUR, AXIAL SECTION."></p> + +<p class="ctr">FIG. 5.--ECHANGEUR, AXIAL SECTION.</p> + +<p>In our engravings, Figs. 1, 2, and 3, the letter A indicates the +germinating cases; B, Saladin's patent turning screws; C A, air +channels; D, passages; E R, main driving shafts; e, pulleys; F, +metal recesses to fit turning screws; G, elevators; H, trap doors; +I, air channels; J, openings to growing floor for air; K S, engines +and fan room; L N, fans, supply and exhaust; T, boiler; U, chimney; +f, well. The capacity of the malting is 130 qr. malt every day. +This is equivalent to an English house of 520 qr. steep. The whole +space occupied is the area necessary for kilns, malt and barley +stores, engine and boiler house, and fans. No additional area is +required for germinating floors, as ten germinating cases, A, are +placed in the basement below the kilns and stores. The building is +of brick, with the internal walls below the ground line resting +upon cast iron columns and rolled joists. The germinating cases, A +A, are of iron; the bottoms are double. One of perforated plate is +placed 6 inches above the bottom. These plates admit of draining +the corn if the germinating case is used as a steeping cistern +also. Their chief object is, however to admit of ready circulation +of the air by the means presently to be described. Large channels, +A a, serve as drains for moisture and to convey the air to or from +the growing corn. Between each case is a passage, D, enabling the +maltster to have free access to the corn at all points.</p> + +<p class="ctr"><img src="images/6d.png" alt= +"FIG. 6.--ECHANGEUR TRANSVERSE SECTION."></p> + +<p class="ctr">FIG. 6.--ECHANGEUR TRANSVERSE SECTION.</p> + +<p>With the exception of the driving shaft, E, all the machinery is +in duplicate, so that the possibility is remote of any breakdown +that would seriously affect the working of the house. This is +necessary, as should the fans, L N, be stopped for twenty-four +hours the corn germinating at a depth exceeding 30 inches would +heat and impair its vitality. The boilers, T, and engines, S, are +of the common type of 20 horse power nominal. The fans, L N, are +the Farcot patent, illustrated a short time since in our pages. The +lower floors of the kilns are provided with the Schlemmer patent +mechanical turners. The turners, Fig. 4, in the germinating cases +are Saladin's patent.</p> + +<p class="ctr"><img src="images/7a.png" alt= +"FIG. 7.--ECHANGEUR, SECTIONAL PLAN."></p> + +<p class="ctr">FIG. 7.--ECHANGEUR, SECTIONAL PLAN.</p> + +<p>The germination of the grain is effected by means of cool moist +air provided by the fan described and the cooler and +moistener--Figs. 5, 6, and 7, herewith--known as an +<i>echangeur</i>. As the germinating grain has a depth of from 30 +inches to 40 inches some pressure is required, and mechanical means +are necessary for efficient and economical turning. The +<i>echangeur</i> is a very ingenious application of the well +understood rapidity of evaporation of any liquid when spread out in +very thin layers over large surfaces and exposed to a current of +air. It consists of a cylinder, or series of cylinders, of +increasing diameter, placed one within another. Each consists of +finely perforated sheet iron. They are placed in a trough of water, +just sufficiently immersed to insure complete wetting. When rotated +at a slow speed, the surfaces of all the cylinders are kept just +wetted. A volume of air is either driven or drawn through, as may +be required for any particular purpose. In the model malting, as +shown at Fig. 4, taken from that shown at the Brewery Exhibition, +the air was driven through the <i>echangeur</i> and thence through +the germinating barley. Here or as employed in the malting +illustrated, the air in its passage comes first into contact with +the moistened cylinders, and if hot and dry it becomes moist and +cool, for the constant evaporation upon the cylinders has a very +considerable refrigerating effect.</p> + +<p>This was well known to the Egyptians over four thousand years +ago, and the porous bottle--<i>gergeleh</i>--of Esnch has been made +until the present day, to keep the drinking water cool and fresh. +The <i>echangeur</i> is like a gigantic gergeleh, and by increasing +the size and number of the cylinders, and causing the water in the +moistening trough to circulate, any volume of air can be wetted to +the saturation limit corresponding to its temperature. It will be +seen that this apparatus gives the maltster complete control of the +humidity and heat as well as volume of the air driven through +germinating corn.</p> + +<p class="ctr"><img src="images/7e.png" alt="Fig. 8."></p> + +<p class="ctr">Fig. 8.</p> + +<p>The turning apparatus is shown by Fig. 4, and consists, as will +be seen, of a cylindrical frame provided with rollers which run on +rails at the edge of the germinating cases. It is carried to and +fro from either end of the case by compensating rope gearing which +at the same time gives motion to the gearing actuating the turning +screws. These screws do not quite touch the bottom of the +germinating case, but are provided with a pair of small brushes, as +shown in the annexed engraving, Fig. 8, which just skim it. The +apparatus shown has but three of these screws, but the cases are +generally made wide enough for six. The kilns are double, each +possessing two floors, and worked upon the Stopes' system. The +construction of the furnaces is of the ordinary French pattern. The +arrangement of the house permits of great regularity in working. +Every day 130 qrs. of barley is screened, sorted, cleaned, and +passed into a steeping cistern. When sufficiently steeped it runs +through piping into the germinating case, which, in the natural +order of working, is empty. Here it forms the couch. When it is +desirable to open couch a small amount of air is forced through the +grain by opening the trap door connected with the main air channel. +This furnishes the growing corn with oxygen, removes the carbonic +acid gas, and regulates temperatures of the mass of grain. Later +the Saladin turner is put in motion about every eight to twelve +hours. The screws in rotating upon their axes are slowly propelled +horizontally. They thus effectually turn the grain and leave it +perfectly smooth. This turning prevents matting of the roots, the +regulation of temperature and exposure to air being effected by +means of the cold air from the <i>echangeur</i>. When the grain is +sufficiently grown it is elevated to the kilns. For forty hours it +remains upon the top floor. It is then dropped upon the bottom +floor, a further charge of green corn following upon the top floor. +The benefit is mutual. The bottom floor is maintained at an even +temperature, being virtually plunged in an air bath; free radiation +of heat is prevented; the top surface of the malt is necessarily +nearly as warm as that next the wires, which in its turn is subject +to lower heats than would be necessary if free radiation from the +surface was allowed. The top floor is by the intervention of the +layer of malt between it and the fire prevented it from coming into +direct contact with heat of a dangerous and damaging degree. The +same heat which is used to dry one floor, and in an ordinary kiln +passes at once into the air as waste, is the best possible +description of heat, namely, very slightly moistened heated air, to +remove the moisture from the second layer of malt at a low +temperature. It is of vital importance to retain this green malt at +a low heat so long as any percentage of moisture exceeding, say, 15 +per cent, is retained by the corn.</p> + +<p>The regulation of temperature is shown by the diagrams, Figs. 9 +and 10:</p> + +<p class="ctr"><img src="images/7b.png" alt="Fig. 9."></p> + +<p class="ctr">Fig. 9.</p> + +<p class="ctr"><img src="images/7c.png" alt= +"Fig. 10."></p> + +<p class="ctr">Fig. 10.</p> + +<p>The distribution of the heated air in the kiln is rarely as +uniform as is supposed, the temperature of the malt on drying floor +being very different at different parts. In illustration of this, +the following may be taken from a statement by Mr. Stopes of the +results of an examination of the temperatures at different parts of +a drying floor in a kiln in Norfolk: "A malting steeping 105 qr. +every four days has a kiln 75 feet by 36 feet; an average drying +area of under 26 feet per qr. The consequent depth of green malt +when loaded is over 10 inches. The total area of air inlets is less +than 27 feet super. The air outlet exceeds 117 feet, a ratio of 13 +to 3. The capacity of head room equals 44,550 feet cube. The area +of each tile is 144 inches, with 546 holes, giving an effective air +area of some 32 inches. The ratio of non-effective metallic surface +to air space is thus 9 to 2." The Casella anemometer gave no +indications at several points, and fluctuating up and down draughts +were observable at many others, especially at two corners and along +the center. "The strongest upward draught pulsated with the gusts +of wind and ranged from 30 feet to 54 feet per minute, a down +draught of equal intensity occurring at intervals at the same spot, +notwithstanding the fact that the air was rushing in at the inlets +below the floor at the high velocity of 785 feet per minute. The +temperatures of the drying malt and superimposed air consequent +upon the conditions thus indicated were naturally as follows: At B, +the place supposed to be hottest: Heat of malt touching tiles, 216 +deg.; heat of malt 1 inch above tiles, 167 deg.; heat of malt 3 +inches above tiles 154 deg.; heat of malt 4 inches above tiles, 152 +deg.; heat of malt 5 inches above tiles, 142 deg.; heat of malt on +surface, 112 deg. At A, the place supposed to be coldest: Heat of +malt next tiles, 174 deg.; heat of malt 2 inches above tiles, 143 +deg.; heat of malt 4 inches above tiles, 135 deg.; heat of malt on +surface, 104 deg.; the heat of the air 3 feet above tiles, 84 deg.; +the heat of the air 5 feet above tiles, 82 deg. Fig. 9 shows the +temperature at twenty-six points close to the tiles, taken with +twelve registered and accurate thermometers in the space of fifteen +minutes." These and other similar tests have led to the conclusion +that the best malt drying cannot be done on a single floor.</p> + +<p>Fig. 10 is a similar diagram showing the temperatures on a +drying floor of kiln at Poole, Dorset, altered to Stopes' system of +drying. The temperature at different depths of the drying grain was +as follows: Malt at surface of tiles, 142 deg.; malt at 1 inch +above tiles, 142 deg.; malt at 2 inches above tiles, 142 deg.; malt +at 4 inches above tiles, 141 deg.; malt on surface, 140 deg.</p> + +<p>The advantages of the Saladin system over that hitherto working +in Britain are numerous, and are thus enumerated by Messrs. Stopes +& Co. who are agents for M. Saladin: The area occupied by the +building does not equal one-third of that otherwise required. The +actual growing-floor space is only about one-seventh, and the +number of workmen is ruled necessarily by the size of the house, +but on an average is reduced two-thirds; but the employment of much +more power is necessary, and the power is used at more frequent +intervals. The use of plant and premises is continuous, the +processes of malting being equally well performed during the summer +months. The further advantage of this is that brewers secure entire +uniformity in age of malt. By the English system the stocks of +finished malt necessarily fluctuate largely. All grain is subjected +to the same conditions of surrounding air, exposure, and +temperature. The volume of air supplied to the germinating corn is +entirely under control, as are also its temperature and humidity. +When germination is arrested and the green malt is drying, the +double kilns insure control of the temperatures of the corn in the +kilns. The infrequency of turning the germinating grain benefits +the growth of the roots and the development of the plumule, besides +saving much labor. No grains are crushed or damaged by the feet or +shovels of workmen. The air supplied to the corn can be +inexpensively freed from disease germs and impurities. The capital +needed for malting can be reduced by the diminished cost of +installation, and the reduced stocks of malt on hand. The quality +of the malt made is considerably improved. The percentages of +acidity are much reduced. The stability of the beer is increased, +and a greater percentage of the extractive matter of the barley is +obtainable by the brewer.--<i>The Engineer</i>.</p> + +<hr> +<p><a name="16"></a></p> + +<h2>NON-SPARKING KEY.</h2> + +<p>Profs. Ayrton and Perry lately described and exhibited before +the Physical Society their new ammeters and voltmeters, also a +non-sparking key. The well known ammeters and voltmeters of the +authors used for electric light work are now constructed so as to +dispense with a constant, and give the readings in amperes and +volts without calculation. This is effected by constructing the +instruments so that there is a falling off in the controlling +magnetic field, and a considerable increase in the deflecting +magnetic field. The deflections are thus made proportional to the +current or E.M.F. measured. The ingenious device of a core or soft +iron pole-piece, adjustable between the poles of the horseshoe +magnet, is used for this purpose. By means of an ammeter and +voltmeter used conjointly, the resistance of part of the circuit, +say a lamp or heated wire, can be got by Ohm's law. Profs. Ayrton +and Perry's non-sparking key is designed to prevent sparking with +large currents. It acts by introducing a series of resistance coils +determined experimentally one after the other in circuit, thereby +cutting off the spark.</p> + +<hr> +<p><a name="17"></a></p> + +<h2>NEW INSTRUMENTS FOR MEASURING ELECTRIC CURRENTS AND +ELECTRO-MOTIVE FORCE.</h2> + +<h3>By Messrs. R. E. CROMPTON and GISBERT KAPP.</h3> + +<p>[Footnote: Paper read before the Society of Telegraph Engineers, +14th February, 1884.]</p> + +<p>In consequence of the rapid development of that part of +electrical science which may be termed "heavy electrical +engineering," reliable measuring instruments specially suitable for +the large currents employed in lighting and transmission of energy +have become an absolute necessity. As usual, demand has stimulated +supply, and many ingenious and useful instruments have been +invented, the manufacture of which forms at the present day an +important industry. Mr. Shoolbred, in a paper which he recently +read before this Society, gave a full and interesting account of +the labors of our predecessors in this field. To-day we add to the +list then given a class of instruments invented by us, examples of +which are now before you on the table. We have preferred to call +them current and potential indicators in preference to meters, +considering that the latter term, or rather termination, ought to +be applied rather to integrating instruments, which the necessities +of electric lighting, we believe, will soon bring into extensive +use. The principal aim in the design of these indicators has been +to obtain instruments which will not alter their calibration in +consequence of external disturbing forces. If this object can be +attained, then it will be possible to divide the scale of each +instrument directly into amperes or volts, as the cause may be, and +thus avoid the use of a coefficient of calibration by which the +deflection has to be multiplied. This is an important consideration +when it is remembered that in many cases these instruments have to +be used by unskilled workmen, to whom a multiplication involving +the use of demical fractions is a tedious and in some cases even an +impossible task.</p> + +<p class="ctr"><img src="images/8a.png" alt= +"FIG. 1. FIG. 2."></p> + +<p class="ctr">FIG. 1. FIG. 2.</p> + +<p>All measurements are comparative. We measure weights or forces +by comparison with some generally known and accepted unit standard +weights, lengths, areas, and volumes, by comparison with a unit +length, resistance by a standard ohm, and so forth. In the same way +currents could be measured by comparison with a standard current: +but this would be a troublesome process, not only on account of the +apparatus necessary, but also because it would be a matter of some +difficulty to have a standard current always ready for use. In +general, measurement by direct comparison with a standard unit is +discarded for the more indirect method of measuring not the current +itself, but its chemical, mechanical, or magnetic effect. The +chemical method is very accurate if a proper density of current +through the surface of the electrodes be used,[1] but since it +requires a considerable time, and, above all, an absolutely +constant current, its use is almost entirely restricted to +laboratory work and to the calibration of other instruments. For +practical ready use, instruments employing the mechanical or +magnetic effect of the current are alone suitable. We weigh, so to +speak, the current against the force of a magnet, of a spring, or +of gravity. The measurement will be exact if the thing against +which we weigh or counterbalance the current itself retains its +original standard value. Where permanent magnets or springs are +used as a balancing force, this condition of constancy in our +weights and measures is not always fully maintained, and to make +matters worse, there is no visible sign by which a change, should +it have occurred, can be readily detected. A spring may have been +overstrained or a steel magnet may have become weakened without +showing the least alteration in outward appearance. To overcome +this difficulty, the obvious remedy is not to use springs or steel +magnets at all, but to substitute for these some other force which +should be either absolutely constant, such as the force of gravity, +or at least should, vary only within narrow limits, and this in +accordance with a definite law. This latter condition can be +fulfilled by the employment of electro-magnets.</p> + +<p>[Footnote 1: According to recent experiments made by Dr. +Hammerl, the density of current in a copper voltameter should be +half an ampere per square inch of surface.]</p> + +<p class="ctr"><img src="images/8b.png" alt="FIG 3."></p> + +<p class="ctr">FIG 3.</p> + +<p>To imitate with an electro magnet as nearly as possible a +permanent magnet, so that the former can be used to replace the +latter, it is necessary that the magnetism in the iron core should +remain constant. This could, of course, be done by exciting the +electro magnet with a constant current from a separate source. (In +a recent note to the Paris Academy of Science, M.E. Ducretet +described a galvanometer with steel magnet, which is surrounded by +an exciting coil. When recalibration appears necessary, a known +standard current from large Daniell cells is sent through this coil +during a certain time, and thus the magnet is brought back to its +original degree of saturation. M. Ducretet also mentions the use of +a soft iron bar instead of a steel magnet, in which case the +current from the Daniell cells must be kept on during the time an +observation is taken.) But such a system would appear to be too +complicated for ready use. Moreover, some sort of indicator would +be required by which we could make sure that the exciting current +has the normal strength.</p> + +<p class="ctr"><img src="images/8c.png" alt="FIG 4."></p> + +<p class="ctr">FIG 4.</p> + +<p>The plan we adopt is to excite the electro magnet by the whole +or a part of the current which is to be measured. Since this +current varies, the power exciting the core of the electro magnet +must also vary; and since we require the core to have as nearly as +possible a permanent magnetic force, we are brought face to face +with the question, whether an electro magnet can be constructed +that has a constant moment under varying exciting currents. This +question has been answered by the well known experiments of Jacobi, +Dub, Mueller, Weber, and others. To get an absolutely constant +magnetic moment, is not possible, but between certain limits we can +get a very near approximation to constancy.</p> + +<p class="ctr"><a href="images/8d.png"><img src= +"images/8d_th.jpg" alt=""></a></p> + +<p>The relation between exciting power and magnetic moment is very +complicated, depending not only on the dimensions and shape of the +core and the manner of winding, but also on the chemical +constitution of the iron of the core. It is not possible, or at +least it has hitherto not been found possible, to embody all these +various elements into an exact mathematical formula, which would +give the magnetic moment as a function of the exciting current; but +the above mentioned experiments have shown that within certain +limits, and in the neighborhood of the point of saturation, the +relation between the two is that of an arc to its geometrical +tangent. It will be seen that for large angles the arc increases +much slower than the tangent; that is, for strongly excited cores, +a very large increase of the exciting current will produce only a +slight increase of magnetic moment. If Mueller's formula were +correct for all currents, absolute saturation could only be reached +with an infinite current. Whether this be the case or not, it is +certain that the greater the exciting current the less will a +variation in it affect the magnetic moment of the core. To imitate +as nearly as possible permanent steel magnets, it is therefore +necessary to use electro magnets, the cores of which are easily +saturated. The core should be thin and long and of the horseshoe +type; the amount of wire wound round it should be large in +comparison with the size of the core.</p> + +<p class="ctr"><a href="images/8e.png"><img src= +"images/8e_th.jpg" alt=""></a></p> + +<p>Here is a magnet partly wound which was used in one of our +earliest experiments, but which was a failure on account of having +far too much mass in the core in comparison with the amount of +copper wire wound round it. Since then we have greatly diminished +the iron and increased the copper. The cores of the instruments on +the table are composed of two or three No. 18 b.w.g. charcoal iron +wires, and are wound with one layer of 0'120 inch wire in the case +of the current indicators, and eighteen layers of 0.0139 inch wire +in the case of the potential indicator. If from the diagram, Fig. +1, we plot a curve the abscissae of which represent exciting +current, and the ordinates magnetic moment of the soft iron core, +we find that a considerable portion of the curve is almost a +straight and only slightly inclined line. If it, were a horizontal +straight line the core would be absolutely saturated, but such as +it is, it answers the purpose sufficiently well, for with a +variation of exciting current from 10 to 100 amperes the magnetic +moment varies but slightly. If a small soft iron or magnetic steel +needle, <i>n s</i>, be suspended between the poles, S N, of an +electro magnet of such proportions as described above, and the +current, after exciting the electro magnet, <i>e e</i>, be lead +round the coils, DD, it will be found that for all currents between +10 and 100 amperes the needle, <i>n s</i>, shows a definite +deflection for each current. Here we have a galvanometer with +permanent calibration. In this case the deflection of the needle +will not strictly follow the law of tangents, because the directing +power of the electro magnet is not absolutely constant; but +whatever the exact ratio between deflection and current may be, it +must always remain the same, and to each angle of deflection +corresponds one definite strength of current.</p> + +<p class="ctr"><a href="images/9a.png"><img src= +"images/9a_th.jpg" alt=""></a></p> + +<p>The force with which the electro magnet tends to keep the needle +in its zero position, that is, in line with the poles, S N, is due +partly to the magnetism of the core, which is nearly constant, and +partly to the magnetic influence of the coils, <i>ee</i>, +themselves, which is, of course, simply proportional to the +current. The total magnetic force acting on the needle is, +therefore, represented by the sum of these two forces, and +consequently not nearly so constant as might be desired in order to +get a good imitation of a tangent galvanometer with a permanent +magnet. In the diagram, Fig. 2, the curve, O A B, represents the +magnetic moment of the iron core, the straight line, ODE, that of +the exciting coils per se, and the dotted line, O F M, the sum of +the two, obtained by adding for every current, O C, the respective +ordinates, CD and C A.</p> + +<pre> + CF = CD + CA +</pre> + +<p>The rise of this curve shows that the force which tends to bring +the needle back to its zero position increases with the current, +though at a slower ratio than the deflecting force of the current. +It follows from this that for large currents the increment in the +angle of deflection is comparatively small, and the divisions on +the scale whereon the current is to be read off would come too near +together to allow accurate readings to be taken. In other words, +the range of accurate reading in an instrument so constructed would +only be limited. But it is very easy to eliminate the magnetic +effect of the coils of the electro magnet on the needle, by +introducing an opposite magnetic effect, so that only that part of +the force remains which belongs to the soft iron core proper. One +way of doing this is by surrounding the needle with a coil, the +plane of which is at right angles to the line, S N, and coupling +this coil in series with the deflecting coil, D D. If the +proportions of this transverse coil and the direction of the +current through it be properly chosen, its magnetic effect can be +made to exactly counterbalance that of the exciting coils, <i>e +e</i>, without perceptibly weakening the magnetism of the iron +core. But instead of employing two coils, one parallel and the +other transversely to the zero position of the needle, we can +obtain the same result in a more simple manner with one coil only, +if this be placed at such an angle that its magnetic effect can be +substituted for the combined effects of the two coils. In other +words, we set the deflecting coil, D D, at a certain angle to the +zero position of the needle.</p> + +<p>A similar arrangement, though not precisely for the same +purpose, has already been suggested and tried by Messrs. Deprez, +Carpentier, Ayrton, and Perry, in galvanometers with permanent +steel magnets. If the coil, D D, be so placed, the deflecting force +which now acts obliquely can be considered as the resultant of two +forces, one acting at right angles to the line, S N, as in an +ordinary galvanometer, and the other parallel to this line, but in +a sense opposed to the action of the electro magnet and its +exciting coils. If the angle of obliquity be so chosen that this +latter component exactly equals the magnetic effect of the exciting +coils <i>per se</i>, an equality which holds good for all currents, +then we shall have an almost perfect imitation of a tangent +galvanometer with permanent magnets. But we can go a step further +than this; we can overbalance the exciting coils by setting the +deflecting coil at a greater angle than necessary for the mere +elimination of the former, and thus attain that an increase of +current results in a slight weakening of the field in which the +needle swings, thus allowing the increment of the angle of +deflection to be comparatively large even for large currents. In +this way it is possible to obtain a more evenly divided scale than +in the case when the deflection follows the law of tangents, as in +an ordinary tangent galvanometer. This principle of overbalancing +the exciting coils is shown on diagram, Fig. 2. The straight line, +O G, represents the magnetic effect on the needle of that component +of the deflecting force which is parallel, but in sense opposed to +S N; as mentioned above, the magnetic effect of the exciting coils +is represented by the straight line, O E. The combined effect of +these two forces on the needle is represented by the line, O K, the +ordinates of which must be deducted from those of the curve, O A B, +in order to obtain the total directing force due to each current. +This is shown by the curve, O P Q, shown in a thick full line. This +curve shows how the directing force or strength of field in which +the needle swings decreases with an increasing current. That this +does actually take place can easily be proved by experiment.</p> + +<p>Fig. 4 shows two curves; the one drawn in a full line is +obtained by plotting the deflection in degrees of the needle of a +potential indicator as abscissae, and the corresponding +electromotive forces measured simultaneously on a standard +instrument as ordinates; the dotted line shows what this curve +would be with an ordinary tangent galvanometer.</p> + +<p>The needle of the potential indicator is mounted at the lower +end of a steel axle, to the upper end of which is fastened a light +aluminum pointer, whereby the deflection of the needle can be read +off on a scale divided directly into volts. The scale is placed +within a circular dial plate with glass cover, giving sufficient +room for the pointer to swing all round, and the needle is placed +within a central tube fitting it closely, which acts as a damper +and so makes the instrument almost dead beat. Tube and dial are in +one casting. The electro magnet is of horseshoe form fastened to a +central tubular stand, which also serves to support the two +deflecting coils, one on either side of it. The tube within which +the magnetic needle swings is inserted into the stand, which is +bored out to the external diameter of the tube. The electro magnet +and deflecting coils are wound with from 50 to 100 ohms of fine +insulated copper wire, and an additional resistance coil of from +450 to 900 ohms of German silver is added, which can, however, be +short circuited by depressing a key when the instrument has to be +used for reading low electromotive forces. In this case the +indication of the pointer must be divided by ten. If a current be +sent through the instrument the wrong way, the needle turns through +an angle of 180°, and thus brings the pointer to the side of +the dial opposite to where the scale is. In this position no +reading can be taken, and to facilitate the sending of the current +in the right direction a commutator is added, and the same is so +coupled up that when the pointer stands over the scale the handle +on the commutator points to the positive terminal screw. There is a +limit of electromotive force below which the indicator fails to +give reliable readings. For instance, an instrument wound with 100 +ohms of copper wire and 900 ohms of German silver can be used for +electromotive forces varying between 300 and 3 volts, but would not +be reliable for measuring less than 3 volts.</p> + +<p>For very exact measurements the instrument should be placed +north and south, in the same position in which it was calibrated. +Two different patterns of current indicators are on the table; one +with double needles suspended on a point in the way compass magnets +are suspended, the other with one lozenge shaped needle mounted on +an axle and pivoted on jewels, in every way similar to the needle +of the potential indicator first described.</p> + +<p>For measurements of currents from 10 amperes upward, there is no +need to employ a complete coil as the deflecting agent; one +half-coil or one strip passing close under the needle gives +sufficient deflecting force, and thus the construction of the +instrument is rendered extremely simple. The current, after +entering at one of the flat electrodes, splits in two parts, each +part passing round the winding of an electro magnet of horseshoe +form, the similar poles of both magnets pointing toward each other +and toward the needle. After traversing the winding, the current +unites again, and passes through a metal strip close under the +needle, and finally out of the instrument by the other electrode, +which lies close under that at which the current entered, but is +insulated from it by a sheet of fiber. The metal strip is set at an +angle, to balance or overbalance, as may be preferred, the magnetic +influence of the exciting coils. The effect of this overbalancing +is shown in Fig. 5, where the full curve represents the current as +a function of the deflection--obtained by comparison with a +standard instrument--and the dotted curve shows what that relation +between deflection and current would be if the law of tangents held +good for these instruments. It will be seen that, about the middle +of the scale, the dotted line coincides nearly with the full line, +while at the extreme end of the scale the dotted line is higher. +From this follows, that if we compare our indicator from which this +curve was taken with any form of tangent instrument showing an +equal angle of deflection at the medium reading, it will be seen +that the needle of our indicator will be deflected to a greater +angle at high readings than that of the tangent galvanometer. +Consequently, the divisions on the scale will be widest apart in +our instruments, which greatly facilitates high readings.</p> + +<hr> +<h2>SECONDARY BATTERIES.</h2> + +<p>The Consolidated Electric Light Company has now completed the +secondary battery which has for some time engaged the attention of +its officers, and their regular manufacture and use for electric +lighting stations have been fairly entered upon. Among other places +to which the batteries have been sent and put into work is +Colchester, where the company has for some time had an installation +at work, chiefly employing incandescent lamps. The battery consists +of lead electrodes, anode and cathode being of the same character. +They are constructed of narrow ribbons of lead, each element being +made from long lengths of the ribbon about or nearly 0.20 in. +width, rolled together into a flat cake like rolls of narrow +webbing, as illustrated by the annexed diagram, Fig. 1, the greater +part of the ribbon being very thin and flat; but intermediate +thicker ribbons are also employed, as in Fig. 2, this thicker +ribbon being corrugated as shown, and affording passage room for +the circulation of the electrolyte. From four to eight coils of the +plain ribbons are between every pair of corrugated ribbons. They +are wound up together tightly, and pressed into the nearly +rectangular form shown. The bar for suspending the coil plates so +made in the cells is soldered to the coil. The object of this +construction is of course to obtain large lead surface, and of +course a much larger surface is so obtained than could be +practically obtained from plain lead plates in the same compass. A +battery thus made may be seen at the offices of the company, 110 +Cannon Street.</p> + +<p class="ctr"><img src="images/9b.png" alt= +"FIG. 1. FIG. 2."></p> + +<p class="ctr">FIG. 1. FIG. 2.</p> + +<p>A very ingenious device for cutting the battery out of circuit +when charged as much as is thought desirable is used by the +company. In a cell is an element which has a determined lower +capacity than those in the rest of the battery. Over this element +is placed a gas-tight chamber in which is a diaphgram, this +diaphragm being of very flexible material placed in the cover of +the box of cells. When charging has proceeded as long as is +desirable, or proceeds too fast, hydrogen is evolved, and this +collecting in the chamber referred to acts upon the diaphragm, and +by means of a rod connected thereto, switches the current, which is +supplied to an electro-magnet and by which circuit is made through +the medium of mercury contacts. The object, of this is to save the +battery from destruction by over-charging or charging by too large +a current.--<i>The Engineer</i>.</p> + +<hr> +<h2>ACETYLENE FROM IODOFORM.</h2> + +<p>P. CAZENEUVE publishes in the <i>Comptes Rendus</i> a new method +for the preparation of acetylene, which consists in mixing iodoform +intimately with moist and finely divided silver. An abundant +evolution of acetylene takes place without heating. The reaction is +represented by the following formula: 2CHI<sub>3</sub> + 6Ag = +C<sub>2</sub>H<sub>2</sub> + 6 AgI. The decomposition of the +iodoform is hastened if the silver is mixed with finely divided +copper, such as can be obtained by precipitating it from its +sulphate by means of zinc.</p> + +<p>Cazeneuve also observed that most metals which have any affinity +for iodine will decompose iodoform in the presence of water, +forming acetylene and an iodide of the metal. By the use of zinc he +obtained a liquid having a pleasant ethereal odor, and a gas +mixture that contained besides acetylene an iodine compound which +burned with a purple-edged, fawn-colored flame.</p> + +<hr> +<p><a name="18"></a></p> + +<h2>WHEN DOES AN ELECTRICAL SHOCK BECOME FATAL?</h2> + +<p>In this age of electricity and electric wires carrying currents +of various intensity, the question of danger arising from contact +with them has caused considerable discussion. An examination into +the facts as they exist may therefore enlighten some who are at +present in the dark.</p> + +<p>To begin with, we often hear the question asked--why is it that +certain wires carrying very large currents give very little shock, +whereas others, with very small currents, may prove fatal to those +coming in contact with them? The answer to this is--that the shock +a person experiences does not depend upon the current <i>flowing in +the wires</i>, but upon the current <i>diverted from them</i> and +<i>flowing through the body</i>.</p> + +<p>The muscular contraction due to a galvanic current, which was +first observed in the frog, gives a good illustration of the fact +that it requires only a very minute current to flow through the +muscles in order to contract them. Thus the simple contact of +pieces of zinc and copper with the nerves generated current +sufficient to excite the muscles--a current which would require a +delicate galvanometer for its detection. What is true of the +muscles of the frog holds good also for the human muscles; they too +are very susceptible to the passage of a current.</p> + +<p>In order to determine the current which proves fatal we need +only to apply the formula which expresses Ohm's law, viz., C=E/R, +or the current (ampere) equals the electromotive force (volt) +divided by the resistance (ohm).</p> + +<p>According to the committee of Parliament investigation, the +electromotive force dangerous to life is about 300 volts; this then +is the quantity, E, in the formula. There remains now only to +determine the resistance in ohms which the body offers to the +passage of the current. In order to obtain this, a series of +measurements under different conditions were made. On account of +the nature of the experiment a high resistance Thomson reflecting +galvanometer was used, with the following results.</p> + +<p>When the hands had been wiped perfectly dry, the resistance of +the body was about 30,000 ohms; with the hands perspiring +ordinarily it fell to 10,000 ohms; whereas when they were dripping +wet it was as low as 7,000 ohms. Our readers can judge this +resistance best when we state that the Atlantic cable offers a +resistance of 8,000 ohms.</p> + +<p>Taking an ordinary condition of the body, with the hands +perspiring as usual, we would have the resistance equal to 10,000 +ohms. Applying the two known quantities in the formula, we get:</p> + +<pre> + C = (300 / 10,000) - (1 / 33.333+) +</pre> + +<p>This means, therefore, that when the electromotive force or +potential is great enough to send a current of 1/33 ampere through +the body, fatal results will ensue. This current is so minute that +it would deposit only about 6 <i>grains</i> of copper in <i>one +hour</i>, a grain being 1/7,000 of a pound.</p> + +<p>Let us now compare these figures with some actual cases, taking +as an example a system of incandescent lighting. In these systems +the difference of potential between any two points of the circuit +outside of the lamps does not exceed 150 volts. Taking this figure, +therefore, it will be seen that under no circumstances can the +shock received from touching these wires become dangerous--not even +by touching the terminals of the dynamo itself; because in neither +case can a current be driven through the body, sufficient to cause +an excessive contraction of the muscles.</p> + +<p>In a system of arc lighting, however, we have to deal with +entirely different conditions; for, while in the incandescent +system the adding of a lamp, which diminishes the resistance, +requires no increase of electromotive force, the contrary is the +case in the arc light system. Here every additional lamp added to +the circuit means an increase in resistance, and consequent +increase in electromotive force or potential. Taking for example a +well known system of arc lighting, we find that the lamps require +individually an electromotive force of 40 volts with a current of +10 amperes. In other words, the difference in potential at the two +terminals of every such lamp is 40 volts. Consequently, if the +circuit were touched in two places, including between them only one +lamp, no injurious effects would ensue. If we touch the circuit so +as to include two lamps between us, the effect would be greater, +since the potential between those two points is 2 x 40 volts. We +might continue in this manner touching the circuit until we had +included about 7 or 8 lamps, when the shock would become fatal, +since the point would be reached at which the difference of +potential is great enough to send a dangerous current through the +body.</p> + +<p>Up to this point we have assumed that, while touching two points +in the wire, the rest of the circuit is perfectly insulated, so +that no current can leak, in other words, that the circuit is +nowhere "grounded." If this is not the case we may, under suitable +conditions, receive a shock by touching only <i>one</i> point of +the wire. This becomes clear by considering the current to leak +from another spot of different potential, to pass through the +ground and into the body; thus, on touching the wire the body +virtually makes a connection between the two points of the circuit. +In clear dry weather such leaks are insignificant; but in damp and +rainy weather, and with poor insulation, they may rise to such a +point at which it would be dangerous to touch the circuit even with +one hand, the leaks being sometimes so great as to cause the lamps +to burn in a fitful, desultory manner, and to go out entirely.</p> + +<p>There is still another factor which enters into the discussion +of the danger of electric light wires. This must be looked for in +the fact that the physiological effects are greatest at the moment +of the opening or the closing of the circuit; or in a closed +circuit they are the more marked when the flow of current stops and +starts, or diminishes and increases. In dynamo electric machines +the current is not absolutely continuous or uniform, since the +coils on the armature being separated a distance cause a slight +break or diminution of the current between each. This break is so +short that it does not interfere with the practical work for +lighting; in some constructions, nevertheless, the distances apart +is so great that, while not interfering with light, its effects +upon the muscles are greatly increased over those of other +constructions which give a more uniform current.</p> + +<p>All these statements might lead to the conclusion that arc light +wires are dangerous under any circumstances; but this is not the +case. The first and only requisite is, that they be perfectly +insulated. When thus protected accidents from them are impossible, +and all mishaps that have occurred through them can be traced +directly to the lack of insulation. Nevertheless, we would warn our +readers against experimenting upon arc wires by actual trial, +because unforeseen conditions might lead to disagreeable +results.</p> + +<hr> +<p><a name="19"></a></p> + +<h2>ROBERT CAUER'S STATUE OF LORELEI.</h2> + +<p>The statue of Lorelei, the mythical siren of the Rhine, +represented in the annexed cut, which is taken from the +<i>Illustrirte Zeitung</i>, was modeled by Robert Cauer, of +Kreuglach on the Rhine. He was born at Dresden in 1831, and is the +son of the well-known sculptor Emil Cauer, and a brother of the +sculptor Karl Cauer.</p> + +<p class="ctr"><a href="images/10a.png"><img src= +"images/10a_th.jpg" alt="LORELEI STATUE BY ROBERT CAUER."> +</a></p> + +<p class="ctr">LORELEI STATUE BY ROBERT CAUER.</p> + +<hr> +<p><a name="14"></a></p> + +<h2>REDUCING AND ENLARGING PLASTER CASTS.</h2> + +<p>Ordinary casts taken in plaster vary somewhat, owing to the +shrinkage of the plaster; but it has hitherto not been possible to +regulate this so as to produce any desired change and yet preserve +the proportions. Hoeger, of Gmuend, has, however, recently devised +an ingenious method for making copies in any material, either +reduced or enlarged, without distortion.</p> + +<p>The original is first surrounded with a case or frame of sheet +metal or other suitable material, and a negative cast is taken with +some elastic material, if there are undercuts; the inventor uses +agar-agar. The usual negative or mould having been obtained as +usual, he prepares a gelatine mass resembling the hektograph mass, +by soaking the gelatine first, then melting it and adding enough of +any inorganic powdered substance to give it some stability. This is +poured into the mould, which is previously moistened with glycerine +to prevent adhesion. When cold, the gelatine cast is taken from the +mould, and is, of course, the same size as the original. If the +copy is to be reduced, this gelatine cast is put in strong alcohol +and left entirely covered with it. It then begins to shrink and +contract with the greatest uniformity. When the desired reduction +has taken place, the cast is removed from its bath. From this +reduced copy a cast is taken as usual. As there is a limit to the +shrinkage of the gelatine cast, when a considerable reduction is +desired the operation is repeated by making a plaster mould from +the reduced copy, and from this a second gelatine cast is taken and +likewise immersed in alcohol and shrunk. It is claimed that even +when repeated there is no sacrifice of the sharpness of the +original.</p> + +<p>When the copy is to be enlarged instead of reduced, the gelatine +cast is put in a cold water bath, instead of alcohol. After it has +swollen as much as it will, the plaster mould is made as before. +For enlarging, the mould could also be made of some slightly +soluble mass, and then by filling it with water the cavity would +grow larger, but it would not give so sharp a copy.</p> + +<hr> +<p><a name="15"></a></p> + +<h2>STRIPPING THE FILM FROM GELATINE NEGATIVES.</h2> + +<p>We have frequent inquiries as to the best means of removing a +gelatino-bromide negative from its glass support so that it can be +used either as a direct or reversed negative, and it does not +appear to be very generally known that about two years ago Mr. +Plener described a method which answers well under all +circumstances, whether a substratum has been used or not.</p> + +<p>If a negative is immersed in extremely dilute hydrofluoric acid +contained in an ebonite dish, say half a teaspoonful to half a pint +of water, the film very soon becomes loosened, and floats off the +glass, this circumstance being due to the solvent action which the +acid exercises upon the surface of the plate as soon as it has +penetrated the film. If the floating film be now caught upon a +plate which has been slightly waxed, and it is allowed to dry on +this plate, it will become quite flat and free from wrinkles. To +wax the plate, it should be held before the fire until it is +moderately hot, after which it is rubbed over with a lump of wax, +and the excess is polished off with a piece of flannel. When the +film is dry, it will leave the waxed glass immediately, if one +corner is lifted by means of a penknife. The film will become +somewhat enlarged during the above-described operation; but, by +taking suitable precautions, this enlargement may be avoided. It is +also convenient to prepare the hydrofluoric acid extemporaneously +by the action of sulphuric acid on fluoride of sodium; and, in many +cases, it is advisable to thicken up the film by an additional +layer of gelatine.</p> + +<p>The following directions embody these points. The negative, +which must be unvarnished, is leveled, and covered with a layer of +warm gelatine solution (one in eight) about as thick as a sixpence. +This done, and the gelatine set, the plate is immersed in alcohol +for a few minutes in order to remove the greater part of the water +from the gelatinous stratum. The next step is to allow the plate to +remain for five or six minutes in a cold mixture of one part of +sulphuric acid with twelve parts of water, and in the mean time two +parts of sodium fluoride are dissolved in one hundred parts of +water, an ebonite tray being used. A volume of the dilute sulphuric +acid equal to about one-fourth of the fluoride solution is next +added from the first dish, and the plate is then transferred to the +second dish, when the film soon becomes liberated. When this is the +case, it is placed once more in the dilute sulphuric acid. After a +few seconds it is rinsed in water, and laid on a sheet of waxed +glass, complete contact being established by means of a squeegee, +and the edges are clamped down by means of strips of wood held in +position by American clips or string. All excess of sulphuric acid +may now be removed by soaking the plate in methylated alcohol, +after which it is dried. It is as well to add a few drops of +ammonia to the last quantity of alcohol used.</p> + +<p>The plate bearing the film negative is now placed in a warm +locality, under which circumstances a few hours will suffice for +the complete drying of the pellicular negative, after which it may +be detached with the greatest ease by lifting the edges with the +point of a penknife.--<i>Photo. News</i>.</p> + +<hr> +<p><a name="1"></a></p> + +<h2>NEW ANALOGY BETWEEN SOLIDS, LIQUIDS, AND GASES,</h2> + +<h3>By W. SPRING.</h3> + +<p>The author asks in the first place, What is the cause of the +different specific gravities of one and the same metal according as +it has been cast, rolled, drawn into wire, or hammered? Does the +difference observed prove a real condensation of the matter under +the action of pressure, or is it merely due to the expulsion by +pressure of gases which have been occluded when the ingot was cast? +According to well-known researches, metals such as platinum, gold, +silver, and copper, which have been proved to occlude gases on +fusion, and to let them escape, <i>incompletely</i>, on +solidification, are precisely those which are most increased in +their specific gravity by pressure. The author has submitted to +pressures of about 20,000 atmospheres metals which possess this +property, either not at all, or to a very trifling extent, and he +finds that though a first pressure produces a slight permanent +increase of density, its repetition makes little difference. Their +density is found to have reached a maximum. Hence the density of +solids, like that of liquids, is only really modified by +temperature. Pressure effects no permanent condensation of solid +bodies, except they are capable of assuming an allotropic condition +of greater density. The author's former researches tend to show +that solid matter, in suitable conditions of temperature, takes the +state corresponding to the volume which it is compelled to occupy. +Hence there is an analogy between the allotropic states of certain +solids and the different states of aggregation of matter. Possibly +the different forms of matter may be due to a single +cause--polymerization. The limit of elasticity of a solid body is +the critical moment when the matter begins to flow under the action +of the pressure to which it is submitted, just as, e.g., ice at or +below 0° may be liquefied by strong pressure. A brittle body is +simply one which does not possess the property of flowing under the +action of pressure.</p> + +<hr> +<p><a name="2"></a></p> + +<h2>HYDROGEN AMALGAM.</h2> + +<p>Hydrogen, although a gas, is recognized by chemists as a metal, +and when combined with any solid metal--as in the case known to +electricians as the polarization of a negative element,--the +compound may correctly be termed an alloy; while any compound of +hydrogen with the fluid metal mercury may with equal correctness be +termed an amalgam of hydrogen, or "hydrogen amalgam." The efforts +of many chemists and mining engineers have for many years been +devoted to a search for some effective and economical means for +preventing the "sickening" of mercury and its consequent "flouring" +and loss. Some sixteen or more years ago, Professor Crookes, +F.R.S., discovered and, after a series of experiments, patented the +use of an amalgam of the metal sodium for this purpose. He made the +amalgam in a concentrated form, and it was added in various +proportions to the mercury used for gold amalgamation. Water +becoming present, it will readily be understood that the sodium, in +being converted into the hydrate (KHO) of that metal, caused a +rapid evolution of hydrogen. The hydrogen thus evolved was the +excess over a certain proportion which enters into combination with +the mercury. While the mercury retained the charge of hydrogen, the +"quickness" of the fluid metal was preserved; but upon the loss of +the hydrogen the "quickness" ceased, and the mercury was acted upon +by the injurious components contained in the ore.</p> + +<p>Since the introduction of the sodium amalgam, many attempts have +been made, more especially in America, to overcome the tendency of +mercury to "sicken" and lose its "quickness." The greater number of +these efforts have been made by the use of electricity as the +active agent in attaining this end; but such efforts have been +generally of a crude and unscientific character. Latterly Mr. +Barker, of the Electro-amalgamator Company, Limited, has introduced +a system--already detailed in these pages--by which the mercury is +"quickened." In his method the running water passing over the +tables, or other apparatus of a similar character, is used as the +electrolyte. In this arrangement, the mercury being the cathode, +plates or wires of copper constituting anodes are brought into +contact with the water passing over the mercury in each "riffle." +Both the cathode and the anodes are, of course, maintained in +contact with the poles of a suitable source of electrical supply. +The current then passes from the copper anode through the running +water to the mercury cathode, and so on to the negative pole of the +electro-motor. As a consequence of this arrangement, hydrogen is +evolved from the water, and has the effect of reducing any oxide or +other detrimental compound of the metal; in other words, it +"quickens" and prevents "sickening" of the fluid metal, and +consequent "flouring" and loss. While the hydrogen is evolved at +the cathode, oxygen enters into combination with the copper +constituting the anodes. This to some extent impairs the +conductivity of the circuit.</p> + +<p>The latest process, however, is that of Mr. Bernard C. Molloy, +M.P., which we have already characterized as highly scientific and +effective, the production of a suitable amalgam being obtained +under the most economical and simple conditions. This process has +the advantage of producing not only a hydrogen amalgam, but also at +will an amalgam of hydrogen combined with any metal +electro-positive to this latter. Thus hydrogen potassium or +hydrogen sodium can be obtained, as will be seen by the following +description.</p> + +<p>Mr. Molloy's effort appears to have been, in the first place, +directed to a system which could be adapted to any existing +apparatus, and in certain cases where water was scarce, to avoid +altogether the use of that, in some districts, rare commodity. For +the purpose of explanation we select an ordinary amalgamating table +fitted with mercury riffles. The surface of the table is in no way +interfered with or disturbed. The bed of the riffle, however, is +constructed of some porous material, such as leather, non-resinous +wood, or cement, which serves as the diaphragm upon which the +mercury rests, and separates the fluid metal from the electrolyte +beneath. Running the full length of the table is a thin layer of +sand, supported and pressing against the diaphragm, and lying in +this sand is the anode, formed preferably of lead. A peroxide of +that metal is formed by the action of the currents, and may be +readily reduced for use over and over again after working for from +one to three months. The peroxide of lead, as is well known, is a +conductor of electricity, and this fact constitutes an important +advantage in the working of the process. The thin layer of sand is +saturated with an electrolyte, such as dilute sulphuric acid +(H<sub>2</sub>SO<sub>4</sub> + 20H<sub>2</sub>O) to give a simple +hydrogen amalgam; (Na<sub>2</sub>SO<sub>4</sub> + xH<sub>2</sub>O) +to give a hydrogen sodium amalgam; or (K<sub>2</sub>SO<sub>4</sub> ++ xH<sub>2</sub>O) to give a hydrogen potassium amalgam. Numerous +other electrolytes constituted by acids, alkalies, and salts can be +used to form an amalgam permanently maintained in a condition of +"quickness" and freed from all liability to "sicken," whatever the +components of the ore may be. The mercury is connected with the +negative pole of the voltaic battery or other electro-motor, and +the lead made with the positive pole of the same source. When the +current passes there is formed according to the nature of the +electrolyte, a hydrogen amalgam, or an amalgam of hydrogen with a +metal electro-positive to hydrogen. The electrolyte, which, it will +be understood, is distinct and apart from the body of water passing +over the table, will last almost indefinitely, there being no +consumption of any of its constituents, excepting hydrogen and +oxygen from the water of solution. The quantity of acid or saline +material contained in the electrolyte is so very small that there +can be no difficulty in finding a supply in any district. The +question of the supply of electricity is one which in many mining +districts involves considerations of practical importance, since a +large supply would necessitate water or steam power. It has been +found that two cells having an electromotive force of about two +volts each will in this process suffice; if preferred, however, a +very small dynamo machine can be used. In connection with the +electro-motive force it is requisite to use, it may be observed +that an amalgam of sodium containing only a small quantity of this +metal would, when constituting a positive element in conjunction +with a lead negative and on an aqueous electrolyte, give an +opposing electro-motive force of less than three volts. Such an +amalgam could therefore be obtained under an electro-motive force +of about four volts. The electrical resistance in the circuit +constituted by the apparatus being very small, no electrical power +is wasted. When water constitutes the electrolyte, as in Barker's +system, then the electro-motive force required to obtain a given +current would be very much greater than that above specified. The +conditions assured under this process appear to be all that can be +required, while the amalgams obtained are those most calculated to +preserve the "quickness" and prevent the "sickening" of the +mercury.</p> + +<p>Mr. Molloy has designed a special form of amalgamating machine +to be used in conjunction with the above process, and with or +without the aid of water. By the employment of this machine, each +particle of the ore is slowly rolled in the quickened mercury for +from fifteen to thirty or more seconds.</p> + +<p>When the extent of the gold and silver mining industries is +considered, and when it is borne in mind that a considerable +percentage of the precious metal present in the ore is, in the +ordinary process of extraction, lost through defective +amalgamation--due to insufficient contact with the mercury or to a +total absence of contact, as in the case of float gold--it is +obvious that the introduction of any system obviating such loss is +a matter of very great importance to those who are interested in +the above mentioned industries. We expect shortly to hear of the +practical introduction on a large scale of Mr. Molloy's process, +and we look forward with interest to the results which may be +obtained from it.--<i>The Engineer</i>.</p> + +<hr> +<p><a name="3"></a></p> + +<h2>TREATMENT OF ORES BY ELECTROLYSIS.</h2> + +<h3>By M. KILIANI.</h3> + +<p>The author lays down general principles for electrolytic +metallurgy. Ores must be distinguished as good and bad conductors; +the former may serve directly as anodes, and are easily oxidized by +the electro-negative radicals formed at their contact, and dissolve +readily in the electrolyte. The bad conductors have to be placed in +contact with a conducting anode, formed of an inoxidizable +substance, such as platinum, manganese peroxide, or coke. In +laboratory experiments a good conducting ore is electrolyzed by +suspension from a platinum wire in connection with the source of +electricity, and is then immersed in the bath. On an industrial +scale the ore, coarsely broken up, is placed in one of the +compartments of a trough divided by a diaphragm.</p> + +<p>On the fragments of the ore which extend up outside of the +electrolytic bath is laid a plate of copper connected with the +positive wire. Care must be taken that this plate does not plunge +into the bath, otherwise the current would not traverse the ore at +all. The cathode is preferably formed of the same metal which is to +be obtained. The bath should not contain organic acids. In practice +the common mineral acids are employed, or their salts, selecting by +preference a salt of the metal which is to be isolated. It is +convenient to pass the current through the greatest possible number +of small decomposition troughs, taking care that the resistance in +each is not too great. With a current of one and the same intensity +we obtain in n troughs n times as much metal as in a single one. To +keep down the resistance of the circuit we employ poles of a large +surface, i.e., plenty of ore and baths which are as good conductors +as possible.</p> + +<p>The state in which the metal is deposited at the negative pole +depends on the secondary actions undergone by the electrolyte, and +especially of the escape of gas. This is a function of the +<i>density</i>, of the current, i.e., the proportion of its +intensity to the surface of the cathode. If the density is too +great there is an escape of hydrogen, and the metal is deposited in +a spongy condition. If the density of the current falls below a +certain minimum, an oxide is deposited in place of metal. The +electrolytic treatment of ores often renders it possible to +separate the different metals which may be present. These are +deposited in succession, and are sharply separated if the +electromotive power is not too great.</p> + +<p>1. <i>Zinc</i>.--The zinciferous compounds--calamine, blende, +and zinc ash--are all poor conductors. They are first dissolved, +and the salts obtained are electrolyzed, employing anodes of coke. +Blende should be roasted before it is dissolved. The electrolytic +bath should be as concentrated as possible to avoid sponginess of +the metal and an escape of hydrogen. In a saturated solution the +formation of hydrogen decreases as the density of the current +augments.</p> + +<p>2. <i>Lead</i>.--Galena is a good conductor, and may be directly +electrolyzed. The best bath is a solution of lead nitrate. The +arborescent crystallizations extend rapidly, and must be broken +from time to time to prevent the formation of a metallic connection +between the anode and the cathode. The sulphur of the galena falls +to the bottom of the bath, and may be separated from the gangue by +solution in carbon disulphide.</p> + +<p>3. <i>Copper</i>.--Native copper sulphide, though a good +conductor, cannot be directly electrolyzed en account of the +presence of iron sulphide, whence iron would be deposited along +with the copper. The copper pyrites are roasted, dissolved in +dilute sulphuric acid, and the liquid thus obtained is submitted to +electrolysis.</p> + +<hr> +<p><a name="30"></a></p> + +<h2>A PEOPLE WITHOUT CONSUMPTION, AND SOME ACCOUNT OF THEIR +COUNTRY--THE CUMBERLAND TABLELAND.</h2> + +<h3>By E. M. WIGHT, M.D., Chattanooga, Tenn., Late Professor of +Diseases of the Chest and State Medicine, Medical Department +University of Tennessee; Late Member of the Tennessee State Board +of Health, and ex-President of the Tennessee State Medical +Society.</h3> + +<p>During the ten years that I have practiced medicine in the +neighborhood of the Cumberland Tablelands, I have often heard it +said that the people on the mountains never had consumption. +Occasionally a traveling newspaper correspondent from the North +found his way down through the Cumberlands, and wrote back filled +with admiration for their grandeur, their climate, their +healthfulness, and almost invariably stated that consumption was +never known upon these mountains, excepting brought there by some +person foreign to the soil, who, if he came soon enough, usually +recovered. Similar information came to me in such a variety of ways +and number of instances, that I determined some four years ago, +when the attempt to get a State Board of Health organized was first +discussed by a few medical men of our State, that I would make an +investigation of this matter. These observations have extended over +that whole time, and have been made with great care and as much +accuracy as possible, and to my own astonishment and delight, I +have become convinced that pulmonary consumption does not exist +among the people native and resident to the Tablelands of the +Cumberland Mountains.</p> + +<p>In the performance of the work which has enabled me to arrive at +this conclusion, I have had the generous assistance of more than +twenty physicians, who have been many years in practice in the +vicinity of these mountains. Their knowledge of the diseases which +had occurred there extended over a, period of more than forty +years. Some of these physicians have reported the knowledge of the +occurrence of deaths from consumption on the Tablelands, but when +carefully inquired into they have invariably found that the person +dying was not a native of the mountains, but, a sojourner in search +of health. In answer to the question: "How many cases of pulmonary +consumption have you known to occur on Walden's Ridge, among the +people native to the mountains?" eleven physicians say, "Not one." +All of these have been engaged in practice there more than three +years, four of them more than ten years, one of them more than +twenty, and one of them more than forty years. All the physicians +of whom inquiries have been made are now residents, or have been, +of the valleys contiguous to Walden's Ridge, and know the mountain +people well. Four other physicians in answer to the same question +say, that they have known from one to four cases, numbering eleven +in all, but had not ascertained whether five of them were born and +raised on the mountains or not. The names and place of death of all +these cases were given, and I have traced their history and found +that but three of them were "natives," or had lived there more than +five years, and that one of these was 57 years of age when she +died, and had suffered from cancer for three years before her +death. The two others died within six months after returning home +from long service in the army, where both contracted their +disease.</p> + +<p>All these investigations have been made with more particular +reference to that part of the Cumberlands known as Walden's Ridge +than to the mountains as a whole. This ridge is of equal elevation +and of very similar character to the main Cumberland range in the +southern part of Tennessee, northwest Georgia, and northwest +Alabama, and what is true of this particular part of the great +Cumberland table is, in the main, true of the remainder.</p> + +<p>Sequatchee Valley lies between Walden's Ridge and what is +commonly known in that neighborhood as the Cumberland Mountains, +and separates it from the main range for a distance of about one +hundred miles, from the Tennessee River below Chattanooga to Grassy +Cove, well up toward the center line of the State. Grassy Cove is a +small basin valley, which was described to me there as a "sag in +the mountains," just above the Sequatchee Valley proper. It is here +that the Sequatchee River rises, and flowing under the belt of +hills which unites the ridge and the main range, for two miles or +more, rises again at the head of Sequatchee Valley. Above Grassy +Cove the mountains unite and hold their union firmly on their way +north as far as our State reaches.</p> + +<p>Topographically considered as a whole, the Cumberland range has +its southern terminus in Alabama, and its northern in Pennsylvania. +It is almost wholly composed of coal-bearing rocks, resting on +Devonian strata, which are visible in many places in the +valleys.</p> + +<p>But a small portion of the Cumberland lies above a plane of +2,000 feet. Walden's Ridge and Lookout Mountain vary in height from +2,000 to 2,500 feet.</p> + +<p>North of Grassy Cove, after the ridges are united, the variation +from 2,000 feet is but little throughout the remainder of the +State, and the general character of the table changes but little. +The great and important difference is in the climate, the winters +being much more severe in these mountains in the northern part of +the State than in the southern, and the summers much more liable to +sudden changes of weather. Scott, Fentress, and Morgan counties +comprise this portion of the table, and these have not been +included in my examination, excepting as to general features.</p> + +<p>In all our southern country, and I may say in our whole country, +there is no other large extent of elevated territory which offers +mankind a pleasant living place, a comfortable climate--none too +cold or too hot--and productive lands. We have east of the upper +waters of the great Tennessee River, in our State, and in North +Carolina and Georgia, the great Blue Ridge range of mountains, +known as the Unaka, or Smoky, Chilhowee, Great and Little Frog, +Nantahala, etc., all belonging to the same family of hills. This +chain has the same general course as the Cumberlands. It is a much +bolder range of mountains, but it is vastly less inhabitable, +productive, or convenient of access. The winters there are severely +cold, and the nights in summer are too cold and damp for health and +comfort, as I know by personal experience of two summers on +Nantahala River. But the trout fishing is beyond comparison, and +that is one inducement of great value for a stout consumptive +<i>who is a good fellow</i>. These mountains are much more broken +up into branches, peaks, and spurs than the Cumberlands. They +afford no table terrritory of any extent. There are some excellent +places there for hot summer visits--Ashville, Warm Springs, +Franklin, and others.</p> + +<p>The Cumberland Mountains, as a whole, are flat, in broad level +spaces, broken only by the "divides," or "gulfs," as they are +called by the inhabitants, where the streams flow out into the +valleys.</p> + +<p>Walden's Ridge, of which we come now to speak particularly, is +the best located of any part of the Cumberlands as a place for +living. From the separation of this ridge from the main range of +Grassy Cove to its southern terminus at the Tennessee River, it +maintains a remarkably uniform character in every particular. From +it access to commerce is easy, having the Tennessee River and the +new (now building) Cincinnati Southern Railroad skirting its entire +length on the east. It rises very abruptly from both the Tennessee +and Sequatchee Valleys, being from 1,200 to 1,500 feet higher than +the valleys on each side. Looking from below, on the Tennessee +Valley side, the whole extent of the ridge appears securely walled +in at the top by a continuous perpendicular wall of sandstone, from +100 to 200 feet high; and from the Sequatchee side the appearance +is very similar, excepting that the wall is not so continuous, and +of less height.</p> + +<p>The top of the ridge is one level stretch of plain, broken only +by the "gulfs" before mentioned and an occasional prominent +sandstone wall or bowlder. The width on top is, I should judge, 6 +or 7 miles. The soil is of uniform character, light, sandy, and +less productive for the ordinary crops of the Tennessee farmer than +the soil of the lowlands. The grape, apple, and potato grow to +perfection, better than in the valleys, and are all never failing +crops; so with rye and buckwheat. Corn grows well, very well in +selected spots, and where the land is made rich by cultivation. The +grasses are rich and luxuriant, even in the wild forests, and when +cultivated, the appearance is that of the rich farms of the Ohio or +Connecticut Rivers, only here they are green and growing the +greater part of the year; so much so that sheep, and in the mild +winters the young cattle, live by the wild grasses of the forests +the whole year. The great stock raisers of the Sequatchee and +Tennessee Valleys make this the summer pasture for their cattle, +and drive them to their own farms and barns or to market in winter. +The whole Cumberland table, with the exception of that small part +which is under cultivation, is one great free, open pasture for all +the cattle of the valleys. Thousands of cattle graze there whose +owners never pay a dollar for pasturage or own an acre of the +range, though, as a rule, most of the well-to-do stock farmers in +the valleys own more or less mountain lands. These lands have, +until quite recently, been begging purchasers at from 12½ to +25 cents per acre in large tracts of 10,000 acres and upward, and +perhaps the same could be said of the present time, leaving out +choice tracts and easily accessible places, which are held at from +50 cents to $2 per acre, wooded virgin lands.</p> + +<p>The forest growth of Walden's Ridge is almost entirely oak and +chestnut. Hickory, perhaps, comes next in frequency, and pine +after. There is but little undergrowth, and where the forests have +never been molested there are but few small trees. This is due to +the annual fires which occur every autumn, or some time in winter, +almost without exception, and overrun the whole ridge. It does not +rage like a prairie fire. Its progress is usually slow, the +material consumed being only the dry forest leaves and grasses. The +one thing essential to its progress is these dry leaves, hence it +cannot march into the clearings. Nearly all the small shrubs are +killed by these fires, otherwise they are harmless, and are greatly +valued by the stock men for the help they render in the growth of +the wild grasses. The free circulation of air through these great +unbroken forests is certainly much facilitated by these fires, +since they destroy every year what would soon become impediments. +The destruction of this undergrowth leaves the woods open, and the +lands are mainly so level that a carriage may be driven for miles, +regardless of roads, through the forests in every direction.</p> + +<p>The shrubs about the fields and places where the forests have +been interrupted by civilization and other causes are blackberry, +huckleberry, raspberry, sumac, and their usual neighbors, with the +azalia, laurel, and rhododendron on the slopes and in the shade of +the cliffs.</p> + +<p>The kinds of wild grasses, I regret to say, I have not noted, +and the same of the rich and varied display of wild flowers.</p> + +<p>The whole ridge is well supplied with clean, soft running water, +even in the driest of the season. There are no marshes, swamps, or +bogs, no still water--not even a "puddle" for long--for the soil is +of such a character, that surface water quickly filters away into +the sands and mingles with the streams in the gulfs. Springs of +mineral water are abundant everywhere. Probably there is not a +square mile of Walden's Ridge which does not furnish chalybeate +water abundantly. Sulphur springs with Epsom salts in combination +are nearly as common.</p> + +<p>The entire extent of Walden's Ridge is underlaid with veins of +coal, and iron ore is plentiful, especially in the foot hills. The +coal and iron are successfully mined in many places on the eastern +slope; on the western they are nearly untouched for the want of +transportation. I find that the impression prevails that the +minerals of the Cumberlands are largely controlled by land agents +and speculators. This is only true as applied to a very small part +of the whole, not more than 1 per cent. The mineral ownership +remains with the lands almost entirely.</p> + +<p>The prevailing winds on Walden's Ridge are from the southwest; +northers and northeasters are of rare occurrence. One old lady who +had resided there for forty years, in answer to my query upon this +subject, said: "Nine days out of ten, the year round, I can smell +Alabama in the air." This was the usual testimony of the residents. +Winds of great velocity never occur there. In summer there is +always an evening breeze, commencing at 4 to 6 o'clock, and +continuing until after sunrise the next morning. In times of rain, +clouds hang low over the ridge occasionally, but they never have +fogs there.</p> + +<p>The range of the thermometer is less on the Tablelands than in +the adjacent valleys. I have had access to the carefully taken +observations of the Lookout Mountain Educational Institute, such +published accounts as have been made by Professor Safford, State +Geologist, Mr. Killebrew, the thorough and painstaking private +record of Captain John P. Long, of Chattanooga, and many more of +less length of time. From all these I deduce the fact that the +summer days are seven or eight degrees cooler on the mountains than +in the Tennessee Valley at Chattanooga, and five or six degrees +cooler than in the Sequatchee Valley, as far up as Dunlay and +Pikeville. The nights on the table are cooler than in the lower +lands by several more degrees than the days; how much I have thus +far not been able to state. The late fall months, the winter, and +early spring are not so much colder than the valleys as the summer +months, the difference between the average temperature of the +mountains and valleys being at that time four or five degrees less +than in the summer. There is no record of so hot a day ever having +occurred on the Cumberladd Mountains as to cause mercury to run so +high as 95° F., or so cold a day as to cause it to run so low +as 10° below zero.</p> + +<p>In the average winter the ground rarely freezes to a greater +depth than 2 or 3 inches, and it remains frozen but a few days at a +time. Ice has been known to form 8 inches thick, but in ordinary +winters, 3 or 4 is the maximum. Snow falls every winter, more or +less, and sometimes remains for a week. Old people have a +remembrance of a foot of snow which lasted for a week.</p> + +<p>Walden's Ridge has a total population of a little more than +4,000, scattered over 600 square miles of surface. The number of +dwellings is about 800. Ninety per cent. of these are log houses; +70 per cent. of them are without glass windows; light being +furnished through the doorways, always open in the daytime, the +shuttered window openings, and the open spaces between the logs of +the walls. Less than 2 per cent. of these houses have plastered +walls or ceilings, and less than 5 per cent. have ceiled walls or +ceilings. About 20 per cent. of them are fairly well chinked with +clay between the logs, the remainder being but indifferently built +in that particular. Fully 90 per cent. of these abodes admit of +free access of air at all times of day and night, through the +floors beneath as well as the walls and roof above. It is the +custom of the people to guard against the coldest of days and +nights by hanging bed clothes against the walls, and many good +housewives have a supply of tidy drapery which they keep alone for +this purpose.</p> + +<p>Wood, always at hand, is the only fuel in use. The whole heating +apparatus consists in one large open fireplace, built of stone, +communicating with a large chimney outside the house at one end, +and frequently scarcely as high as the one story building which +supports it. This chimney is constructed in such a manner as to be +a great ventilator of the whole room, quite sufficient, it would be +thought, if there were no other means of ventilation. It is usually +made of stone at the base, and that part above the fire is of +sticks laid upon one another, cobhouse fashion, and plastered over +inside and between with similar clay as that with which the house +walls are chinked.</p> + +<p>Very few of these houses are more than one story high. They are +all covered with long split oak shingles--the people there call +them "boards"--rifted from the trunks of selected trees. There is +no sheathing on the roof beneath these shingles. They are nailed +down upon the flat hewn poles running across the rafters, at +convenient distances. Looking up through the many openings in the +roof in one of these house, one would think that this would be but +poor protection against rain, but they rarely leak.</p> + +<p>Not one family in fifty is provided with a cooking stove. They +bake their bread in flat iron kettles, with iron covers, covered +with hot coals and ashes. These they call ovens. The meat is fried, +with only the exception of when accompanied by "turnip greens."</p> + +<p>The question, "What is the principal food of the people who live +on these mountains?" has been asked by me several hundred times. +The almost invariable answer has been, "Corn bread, bacon, and +coffee." Occasionally biscuits and game have been mentioned in the +answers. All food is eaten hot. Coffee is usually an accompaniment +of all three meals, and is drunk without cream and often without +sugar. Some families eat beef and mutton for one or two of the +colder months in the year on rare occasions, though beef is +commonly considered "onfit to go upon," as I was told upon several +occasions, and mutton sustains less reputation. Chickens are used +for food while they are young and tender enough to fry, on +occasions of quarterly meetings, visits of "kinfolks" or the +"preachers" and the traveling doctors. Fat young lambs are plenty +in many settlements from March to October, and can be had at fifty +cents each, but I could not learn that one was ever eaten.</p> + +<p>A large majority of the adult population use tobacco in some +shape--the men by chewing or smoking, the women by smoking or +dipping snuff. They never have dyspepsia, nor do they ever get +flesh, after they pass out of childhood, though nearly all the +children are ruddy in appearance, and well rounded with fat.</p> + +<p>One physical type prevails among the people in middle life, and +carries along into old age but little change; and old age is common +there. Nearly every house has its old man or old woman, or both. +Everybody, father and mother, and frequently grandfather and +grandmother, is still on hand, looking as brisk and moving about as +lively as the newer generations. After they pass their forty years, +they never seem to grow any older for the next twenty or thirty, +and the grandfathers and grandmothers can scarcely be selected, by +comparison, from their own children and grandchildren. The men are +taller than the average, and the women, relatively, taller than the +men. They are all thin featured, bright eyed, long haired, sharp +looking people, with every appearance of strength and power of +endurance.</p> + +<p>I think the men who live on Walden's Ridge can safely challenge +the world as walkers--aborigines and all; and unless the challenge +should be accepted by their own women folks, I feel quite sure they +would "win the boots." They go everywhere on foot, and never seem +to tire.</p> + +<p>Nearly all the people of the Tablelands are employed in the +pursuits of agriculture. Very few of them seem to be hard workers. +The men are all great lovers of the forest sports, much given to +the good, reliable, old fashioned long rifles. The women and +children are much employed in out door occupations, and live a +great portion of their time in the open air. The clothing of all +classes is scanty. The use of woolen fabrics for underwear has not +yet been introduced, and coarse cotton domestic is the universal +shirting, and cotton jeans, or cotton and wool mixed, constitute +the staple for outer wearing apparel. The men wear shoes throughout +the year much more commonly than boots. They never wear gloves, +mittens, scarfs, or overcoats, and they scorn umbrellas. Probably +this whole 4,000 people do not possess two dozen umbrellas or twice +as many overcoats. The women go about home with bare feet a great +part of the summer. They never wear corsets or other lacing.</p> + +<p>I have learned by careful inquiry that very few of the people of +the Ridge have ever had the diseases of childhood. Scarlet fever I +could hear of in but two places, and I suppose that not one person +in fifty has had it. Whooping cough and measles have occurred but +rarely, and the large majority have not yet experienced the +realities of either. Very few people there have ever been +vaccinated, nor has smallpox ever prevailed. Typhoid, typhus, and +intermittent fevers are unknown. In the great rage of typhoid fever +which took place ten or twelve years ago in the Tennessee and +Sequatchee Valleys, not a single case occurred on the Mountains, as +I have been informed by physicians who were engaged in practice in +the neighborhood at the time. Diphtheria has never found a victim +there; so of croup. Nobody has nasal catarrh there, and a cough or +a cold is exceedingly rare.</p> + +<p>I have said that these observations refer more particularly to +Walden's Ridge than to the Cumberland Tablelands in our State as a +whole. This ridge was chosen by me for this examination, mainly for +the reason of its convenience, but partly owing to its being more +generally settled than any other equal portion of the table which +lies in Tennessee. Lookout Mountain is not as well located; it is +on the wrong side of the Tennessee River, and but a few acres of it +belong in this State. Sand Mountain is altogether out of the State, +but it is perhaps nearer like Walden's Ridge in its physical +features than Lookout. That part of the Cumberlands west of +Sequatchee Valley is Walden's Ridge in duplicate, excepting that it +is further west, and nearer the Middle Tennessee basin. There are +some small towns, villages of miners, and summer resorts there, +which interferes with that evenness of the distribution of +population which Walden's Ridge has, rendering it more liable to +visitations of epidemic and contagious diseases. The tablelands +north of the center line of the State, above Grassy Cove, are very +similar to Walden's Ridge, as far up as Kentucky, with the +exception before mentioned--that of climate--it being from one to +ten degrees colder in winter.</p> + +<p>This whole Cumberland Table is no small country. It comprises +territory enough to make a good sized State. At present, it is +almost one great wilderness, in many particulars as unknown as the +Black Hills. It is coming into the world now, and will be well +known in a few years. The great city of Cincinnati has determined +to build a railroad through the very center of this great table in +the north part of the State, connecting with Chattanooga in the +southern part. This road is nearly bored through, and in another +year or two the Cumberland Tablelands in Tennessee will be much +heard of at home and abroad.</p> + +<p>It seems to me this country has merits. It is located in the +latitude of mild climate; not so far south as to be scorched by the +hot summer sun, or visited by the great life destroying epidemics; +not so far north as to meet the severe and lengthened winters.</p> + +<p>Climate, we know, is a fixture; it has a government; it has +rules; the weather may change, but climate does not; it is a +permanent out-door affair, and what is true of to-day was true +centuries ago, and will be true forever, in the measure of any +practical scope, at least. The people of the world are beginning to +know that the greatest destroyer of human life has its remedy in +climate.</p> + +<p>Mr. Lombard, in his famous exhibit in relation to the prevalence +of consumption among the people of different occupations, +circumstances of life, and place of dwelling, gives the lowest +number of deaths from this cause to those who live in the open air. +He found the people who lived most in the open air, as would be +readily conjectured, in the mild latitudes, not in the countries of +hot sands or cold snows.</p> + +<p>[The above article, in regard to which we have noticed frequent +allusions in many of our exchanges, all erroneously attributing it +to <i>Dr. Wright</i>, of Tennessee, and for which we have received +repeated requests quite recently, was read by the lamented Dr. E.M. +Wight at the 43d annual meeting of the Tennessee State Medical +Society, held at Nashville, April 4, 5, and 6, 1876. Its +distinguished and talented author will long be remembered as one of +the most active, earnest, and zealous members of the State Society. +At this meeting he also read a very admirable paper on "The +Microscopic Appearance of the Blood in Syphilis," and prepared the +report of the Committee on State Board of Health, to which report +may be ascribed the honor of securing the necessary legislation +organizing the Board. A true, upright, honest man, an earnest, +devoted and zealous physician, universally esteemed and beloved by +all who knew him; himself the subject of tuberculosis, dying in the +prime of a brilliant manhood. He had but few equals in the glorious +profession he honored and loved so well.</p> + +<p>From a careful reading of his paper, we find that he describes a +large area of territory, free, absolutely free, from subsoil +moisture, a climate mild and equable, a soil capable of producing +nearly everything necessary for the comfortable maintenance of +human life, surroundings that tempt, nay, compel the greatest +possible amount of open air life. His description is exceedingly +accurate of a plain, primitive, simple-minded people with but few +wants, many of the virtues and few of the vices of humanity. With +their surroundings, soil, climate, residence, and mode of living, +need we be surprised that "there is a people," or a land "free from +consumption"?--ED.]--<i>Southern Practitioner</i>.</p> + +<hr> +<p><a name="31"></a></p> + +<h2>THE TREATMENT OF HABITUAL CONSTIPATION.</h2> + +<p>Dr. F.P. Atkinson thus writes in the <i>Practitioner</i>, +January, 1884: I suppose there is no derangement of the system we +are more frequently called upon to treat than habitual +constipation; and though all kinds of medicines are suggested for +its relief, they rarely produce more than temporary benefit--and it +is difficult to see how the result can well be otherwise, while the +root of the evil remains untouched. Now by far the more numerous +subjects of this disorder are women; and as they do not seem to +know that regularity is essential to the performance of every one +of nature's operations, they appoint no stated times for trying to +get the bowels relieved, but trust to receiving intimation when the +rectal accumulation and distension can be borne no longer. This +method of action may and does answer fairly well for a time; but +nature gradually gets upset, the sensation of the lower bowel +becomes blunted, and at last it ceases to respond to the ordinary +stimulus. Then aperients are regularly resorted to, and although +these act fairly well for a time, they gradually have to be +increased in strength and frequency. Now, as regards the treatment, +the first thing to be accomplished is of course to get the rectum +well relieved; the next, to get the actions to take place at fixed +times; and lastly, it is necessary to get more tone imparted to the +muscular tissue of the bowels, so that the regularity of action may +be helped and also maintained. In order, then, to get the bowels +relieved in the first instance, it is well to give five grains of +both compound colocynth and compound rhubarb pill at bed-time (this +rarely requires to be repeated), then to take a tumblerful of cold +water the next morning on waking, and repeat it regularly at the +same time each day. Should the bowels remain sluggish for some +time, the same quantity of water may be taken daily before each +meal. Supposing no action takes place on rising or shortly after, a +small injection of warm water may be resorted to. After each +movement of the bowels, a small hand-ball syringeful of <i>cold</i> +water should be thrown into the rectum and retained. A soup +plateful of coarse oatmeal porridge (made with water and taken +according to the Scotch method, viz., by filling half the spoon +with the hot porridge and the other with cold milk) each night at +bed-time, or even every night and morning for a time, is often a +very great help. But above all things, it is necessary for the +patient to <i>try</i> and get relief at a certain <i>fixed</i> time +regularly every day. If these directions are strictly carried out +in their entirety, the evil, even if it has been of long standing, +will generally be corrected, and the patient will improve in health +and appearance. Of course where the constipation results from +exhaustion of the nervous system (such, for instance, as is brought +about by self-abuse), the special cause has to be taken into +consideration, and such treatment adopted as is suited to the +particular necessities of the case.</p> + +<hr> +<p><a name="20"></a></p> + +<h2>THE PYRAMIDS OF MEROE.</h2> + +<p>About fifty miles from the mouth of the Atbara, and, of course, +on the eastern bank of the Nile, stand the pyramids of Meroe. They +consist of three groups, and there are, in all, about eighty +pyramids. The presumption is that they represent the old sepulchers +of the kings of Meroe. Candance, Queen of the Ethiopians, mentioned +in Acts, chap. viii., v. 27, is supposed to have belonged to Meroe, +that being the name also of the capital, which is understood to +have been somewhere not far distant from the sepulchers. These +pyramids of Meroe possess one marked feature, distinguishing them +from the pyramids of Egypt proper--that is, they have an external +doorway or porch. As there is no entrance to the pyramid at these +porticoes, it is quite possible that they were temples for worship +or making offerings to the dead. By comparing them with the +pyramids of Ghizeh, it will be seen that they are also taller in +proportion to their base. Another important point in these porches +or temples is the existence of the arch; and that, too, an arch in +principle, with a keystone.--<i>Illustrated London News</i>.</p> + +<p class="ctr"><a href="images/13a.png"><img src= +"images/13a_th.jpg" alt= +"THE PYRAMIDS OF MEROE, ON THE NILE."></a></p> + +<p class="ctr">THE PYRAMIDS OF MEROE, ON THE NILE.</p> + +<hr> +<p><a name="24"></a></p> + +<h2>THE PROLIFICNESS OF THE OYSTER.</h2> + +<p>In an article by Prof. Karl Mobius on "The Oyster and Oyster +Culture," reproduced in the recently issued report of the U. S. +Commissioner of Fish and Fisheries, the author says:</p> + +<p>A mature egg-bearing oyster lays about one million of eggs, so +that during the breeding season there are upon our oyster beds at +least 2,200,000,000,000 young oysters, which surely would suffice +to transform the entire extent of the sea-flats into an unbroken +oyster bed; for if such a number of young oysters should be +distributed over a surface 74 kilometers long by 22 broad, 1,351 +oysters would be allotted to every square meter. But this sum of +2,200,000,000,000 young oysters is undoubtedly less than that in +reality hatched out, for not only do those full-grown oysters which +are over six years of age spawn, but they begin to propagate during +their second or third year, although it is true that the young ones +have fewer eggs than those which are fully developed. At a very +moderate estimation, the total number of three to six year old +oysters which lie upon our beds will produce three hundred billions +of eggs. This number added to that produced by the five millions of +full grown oysters would give for every square meter of surface not +merely 1,351 young oysters, but at least 1,535. In order to +determine how many eggs oysters produce, they must be examined +during their spawning season. This begins upon the +Schleswig-Holstein beds in the middle of June, and lasts until the +end of August or beginning of September. The spawning oyster does +not allow its ripe eggs to fall into the water, as do many other +mollusks, but retains them in the so-called beard, the mantle, and +gill-plates until they become little swimming animals. The eggs are +white, and cover the mantle and gill-plates as a semi-fluid, +cream-like mass. As soon as they leave the generative organs the +development of the germ begins. The entire yolk-mass of the egg +divides into cells, and these cells form a hollow, sphere-like +body, in which an intestinal canal arises by the invagination of +one side. Very soon the beginnings of the shell appear along the +right and left sides of the back of the embryo, and not long +afterward a ciliated pad, the velum, is formed along the under +side. This velum can be thrust out from between the valves of the +shell at the will of the young animal, and used by the motion of +its cilia as an organ for driving food to the mouth, or in swimming +as a rudder. During these transformations the original cream-white +color of the germ changes into pale gray, and finally into a deep +bluish-gray color. At this time they have a long oval outline, and +are from 0.15 to 0.18 of a millimeter in breadth. Over 300,000 can +find room upon a square centimeter of surface. If an oyster in +which the embryos are in this condition is opened, there will be +found upon its beard a slimy coating thickly loaded with +grayish-blue granules. These granules are the embryo oysters, if a +drop of the granular slime be placed in a dish with pure sea water, +the young animals will soon separate from the mass, and spread +swimming through the entire water. When the embryos are at this +stage their number may be estimated in the following manner: The +whole mass of embryos is carefully scraped from the beard of the +mother oyster by means of a small hair brush. The whole mass is +then weighed, and afterward a small portion of the mass. This small +portion is then diluted with water or spirits of wine, and the +embryos portioned out into a number of small glass dishes, so that +they can be placed under the microscope and counted. Thus, knowing +the weight of the small portion and the number of embryos in it by +count, we can estimate the total number of embryos from the weight +of the entire mass, which is also known. In this manner I estimated +the number of embryos in each of five full grown Schleswig-Holstein +oysters caught in August, 1869, and found that the average number +was 1,012,956.</p> + +<p>Notwithstanding this great fecundity, but an extremely small +proportion of the young oysters produced during the course of the +summer arrive at maturity, 421 only out of 500,000,000 escaping +destruction. The immolation of a vast number of young germs is the +means by which nature secures to a few germs the certainty of +arriving at maturity. In order to render the ideas of +germ-fecundity and productiveness more easily understood, Prof. +Mobius makes the following comparison between the oyster and +man:</p> + +<p>According to Wappaus, for every 1,000 men there are 347 births. +According to Bockh, out of every 1,000 men born 554 arrive at +maturity, that is, live to be twenty years or more of age; thus, on +an average, 347 children are produced from 554 mature men, or 626 +children from 1,000 mature men. Since 1,000 full-grown oysters +produce 440,000,000 of germs, then the germ fecundity of the oyster +is to the germ fecundity of man as 440,000,000 to 6.26, or as +7,028,754 to 1. On the other hand, the number which arrive at +maturity is 579,002 times as great with mankind as with the oyster; +for of 1,000 human embryos brought into the world 554 arrive at +maturity, or of 440,000,000 newly born 243,760,000 would live to +grow up, while of 440,000,000 young oysters only 421 ever become +capable of propagating their species. The proportion is then 421 to +243,760,000, or as 1 to 579,002. I am fully persuaded that these +figures represent the number of oysters which arrive at maturity +more favorably than is really the case, since from every thousand +of full grown oysters it is certain that, on an average, more than +440,000,000 young are produced.</p> + +<hr> +<p><a name="21"></a></p> + +<h2>RED SKY.</h2> + +<p>The beautiful red sky which has been so frequent of late, +morning as well as evening, has excited much comment. The comment, +however, has consisted more of description, statement of fact, +theory, and wonder as to cause, rather than as to satisfactory +explanation.</p> + +<p>Facts in the case which would reveal the secret of this +beautiful display of nature are not complete and numerous enough at +present to establish the cause of this phenomenon on a sure basis; +yet enough facts, it would seem, have been obtained to satisfy the +strong mind capable of bridging over a wide expanse.</p> + +<p>Facts in an argument are like piers to a bridge-the more we have +of them, c. p., the more substantial the structure. When the facts +are <i>legion</i>, the structure becomes a causeway, and there is +no need of argument.</p> + +<p>Argument is a bridge--the fewer the facts, the more the +necessity for the bridge; the less the facts, the more argument +necessary to connect the few we have, and the more skill is +required to make substantial connecting links between the few solid +piers (facts) that exist.</p> + +<p>One of the queer things in connection with this is, the public +have looked chiefly, if not wholly, to the astronomers for an +explanation of this phenomenon, when it is not their special +province to explain matters in this department of nature.</p> + +<p>The explanation belongs to the department of meteorology, and +not to astronomy. But the fact of having looked to the astronomers +shows how little the world knows of meteorology and how few +meteorologists there are able, ready, and willing to rise and +explain in face of the opposition of the public, who seem to think +that the explanation must necessarily belong to astronomy. +Astronomy proper deals with the position of the earth in space and +its relation to the other heavenly bodies, whether suns, fixed +stars, planets, satellites, comets, or other bodies in the vast +space about us. Meteorology deals with the atmosphere of the globe, +in all its forms. Astronomy could be studied in the early ages; its +grand facts were not wholly dependent upon the advanced condition +of the mechanic arts; it could be studied even without the aid of +telescopes, though telescopes have added much to its advancement. +Meteorology, on the contrary, depended on the advancement of the +arts and sciences; they must first be perfected ere we could know +much about this branch of science. To one unfamiliar with the +advancement and perfection of meteorology within the past ten +years, this statement may seem strange, yet it is an undisputable +fact that, prior to the establishment of the daily weather reports, +the knowledge on this subject amounted to very little, and was not +even worthy of being designated a science. Prior to the advent of +the weather map the world was in absolute ignorance of the laws +governing the atmosphere. Sure, we had had large volumes on the +laws of storms, but the later revelations leave them shelved high +and dry on the shores and as useless as a wreck in a similar +condition; with the daily weather map before us we have no need to +even open these huge volumes; they are completely circumvented, and +only negative in value--to show how little was known of the subject +without the full and complete facts daily collected and spread +before us on the map published by the Weather Bureau.</p> + +<p>In order to understand the color of our sky, we must understand +the subject which is so immediately connected with it and its +creation.</p> + +<p>The earth is a sphere in space; generally speaking, it is +composed of land and water. These are two factors; the heat that it +derives from the sun forms a third factor; the three--land, water, +and heat--are essential to life, at least the higher conditions of +life which culminate in man. The old physical geography taught us +this much, but it was not able to go further and tell us why it was +cold or warm independent of the seasons; it could not explain why +it was at times as warm, and even warmer, half-way to the pole than +at the equator; why it was at times very warm in the extreme +northeast while very cold in the Southern States; cold in the +northwest when it was warm in the northeast, and warm in the +northwest when cold all along the upper Atlantic seaboard; it could +not forewarn us of storms. These and a host of other facts, which +the weather map makes as plain as astronomy demonstrates that +Jupiter is a planet, the new revelation, through the +instrumentality of the perfected telegraph system, makes +exceedingly plain to us if we will but seek the easily obtained +information.</p> + +<p>The principal revelations of the weather map are the facts in +regard to the areas of high and low barometer, and the influence +they exert upon the climate of the globe.</p> + +<p>These conditions--high and low barometer--move on general lines +from the west towards the east, or towards the rising sun, and +around the world in irregular belts. The centers of low barometer +are various distances apart, from a thousand to two thousand and +even more miles apart--call the average about two thousand +miles.</p> + +<p>The clouds are formed from the moisture present by the action of +the sun's heat. The direction of the wind is from the area of high +barometer to that of low. The nearer the winds approach the center +of "low" (low barometer), the more they partake of the lines of the +volute curve, or curve of the sea shell or water in a whirlpool. +High barometer is the atmospheric hill; low barometer is the +atmospheric valley. But time at present will not permit more than +these general statements; a close study of the weather map for a +season will reveal the beautiful minor details.</p> + +<p>To the reader it may seem a long way round, yet in order to +fully understand the nature of the atmosphere which surrounds our +globe we must pay due attention to these newly discovered physical +laws.</p> + +<p>The red sky which was so noticeable, in the fall of 1883, the +astronomers have told us was due to "meteoric dust" which was +produced by the volcanic eruption on the island of Java, August 27, +1883.</p> + +<p>This "meteoric dust" they say combined with the atmosphere, +followed it around the earth, and caused the beautiful redness of +the sky at morning and evening. For one, I do not believe dust of +any description in the atmosphere would produce such an effect.</p> + +<p>There is nothing luminous, transparent, or delicate about dust. +Dust would not remain in the atmosphere for months, it would settle +in a very short time, and if thick enough in the atmosphere to +obstruct the light of the sun it would be visible, discernible, to +the eye, and manifest on the face of nature. Years ago, before the +age of the weather map, we might have thought that the atmosphere +followed the surface of the earth like the water on a grindstone, +but it does not. As already seen, the wind is from the area of high +barometer to that of low, and there are many of these "low +centers."</p> + +<p>From the best calculation we can make at present, there would be +at least some six centers on an average between the center of the +United States and the island of Java. In addition to this there +would also be a number of belts of "low" centers, which would +complicate the thing threefold at least. At all these different +centers the winds would be blowing from all points of the compass +at the same time. Such winds would not be apt to bring the +"meteoric dust" from Java to the United States, either in an +easterly or westerly direction. But, it is said, "dust" has been +gathered.</p> + +<p>How high from the surface of the ground has this <i>dust</i> +been gathered--at what elevation?</p> + +<p>There is undoubtedly a little dust in the air most of the time, +but I do not think that it extends very high. Where it would be the +highest and most perceptible would be on the arid plans of Africa +and Asia, when the <i>simoom</i> is passing, or in the track of a +tornado. But from the multiplicity of these storm centers and the +varied winds they would produce even this dust could not travel +from Java to America.</p> + +<p>Again, all clouds, no matter how high or how low, are affected +by the low centers, as the movement of clouds prove, and travel +from the "high" to the "low," from and to all points of the +compass. High authority gives the heights of the clouds as follows: +lower clouds, 16,000 feet; upper clouds, 23,000 feet.</p> + +<p>As all clouds, from the highest to the lowest, are affected by +the centers as above referred to, it follows that if this "meteoric +dust" follows the earth around, as it would have to do in order to +make good this theory, it would have to travel suspended in the +atmosphere above the upper clouds, or at a height of more than +23,000 feet, or at an elevation of over four miles!</p> + +<p>Now, is it reasonable to believe that dust, however fine, will +remain in the atmosphere at that elevation for over six months?</p> + +<p>As a side argument it is suggested that the smoke of the burning +woods, or few years ago in Michigan, caused as peculiar condition +of the atmosphere. This extensive fire was on a day when the area +of low barometer was on a high line of latitude and passing to the +eastward. This naturally took the smoke, which is far lighter than +dust, along with it. It mingled with the muggy condition of an +extensive "low," and produced a yellowness of the atmosphere. This +however was of only a few hours' duration, and was only visible in +favorable localities.</p> + +<p>Here again we see the advantage of the weather maps; but for +this map we would never have been able to have satisfactorily +explained the peculiar phenomenon produced by the great Michigan +fire.</p> + +<p>If the delicate redness of the sky is not caused by dust, what +is it caused by?</p> + +<p>But for the weather map, I think we should still be in the dark +in regard to it.</p> + +<p>In the first place, this redness is nothing new, only the +conditions are more favorable sometimes than at others. It has +always existed and always will exist, independent of earthquakes, +volcanoes, etc. Nature is ever changing; the movements of the +atmosphere more resemble the kaleidoscope than any thing else.</p> + +<p>The summer and fall of 1883, the movements of "high" (high +barometer) over the United States were quite central and extensive, +causing this peculiar phenomenon over a wide extent of +territory.</p> + +<p>We have no information of the condition of the barometer over +the other part of the world; we speak move particularly of the +United States; yet if certain conditions produce certain effects +here, it is quite safe to say that the same effects are produced by +the same cause elsewhere.</p> + +<p>As now well established by the map, the surface wind is from the +area of high barometer to that of low--from the atmospheric hill to +the atmospheric valley.</p> + +<p>The tendency of this is to free "high" of all clouds and +moisture; but then it is impossible to free "high" entirely of +moisture; a little will remain, and it is just this little, which +is highly rarefied, that produces the result. We look around us and +above, we see little or no evidence of evaporation, yet it is the +while going on. When the sun is immediately below the horizon, +where it will shine horizontally through the mass of light, +suspended moisture, the delicate presence of vapor heretofore +unnoticed is revealed. The action of the sun's rays is the same as +when illuminating a well formed cloud--it is an embodiment of the +same principle, but the material is much more expanded. The +particles of suspended moisture are very fine, few and far between, +therefore the effect of the light upon it is more diffused and +transparent. It is much like looking through a piece of window +glass flatwise and endwise; flatwise we do not perceive any color; +endwise, from seeing through a greater mass, the glass has a very +perceptible green color.</p> + +<p>We see the same idea also in the rising and setting sun and +moon. On a clear, cloudless night, when nothing seems to interfere +with the brightness of the stars, we cannot, by looking upward, +perceive any moisture present in the atmosphere; but if we cast our +eyes to the horizon, whereby we see through the mass of atmosphere +endwise, as it were, and note the appearance of the stars there, or +the rising or setting moon, we will see that the atmosphere there +gives a redness to the rising body, which it does not have when it +has ascended to mid-heaven. On a clear night, which is caused by +the presence of the area of high barometer, the moon when in +mid-heaven is of a clear, silver-white, and it is the same moon +that at the horizon was a deep red. The color of the moon has not +changed; it is simply the medium through which it is seen that +produces the difference in color.</p> + +<p>Occasionally, on a clear, bright ("high") night, when the moon +is full, prior to rising, when just below the horizon, it will so +illuminate this lower strata of atmosphere as to appear like a +great fire; the moon rises red, but its deep color gradually fades +as it rises, and when well up in the heavens we perceive that this +deep coloring was an illusion and merely the influence of its +surroundings. I never, though, knew of any one to attempt to +account for this by "meteoric dust;" and yet it is an embodiment of +the same principle. Place the sun where the moon is, and from its +far superior abundance of light we have a much grander display.</p> + +<p>Under no other conditions or relations of the sun and earth is +it possible to have this phenomenon of the delicate red sky but +when a positive area of high barometer is passing and extends over +us. In order to produce this effect we must have the clear +atmosphere of high barometer, when there is a minimum of moisture +present. The action of the sun's rays upon this extensive area of +slightly moist rarefied air is unconfined by clouds, and reaches +far and wide, and produces a delicacy of color which from no other +source or condition can be realized.</p> + +<p>ISAAC P. NOYES.</p> + +<p>Washington, D. C., 1884.</p> + +<hr> +<p><a name="22"></a></p> + +<h2>A THEORY OF COMETARY PHENOMENA.</h2> + +<p><i>To the, Editor of the Scientific American</i>:</p> + +<p>The following subject, substantially, was written more than a +year ago with a view to its publication. It was not, however, until +January of the present year that I sent a brief communication to +the <i>Brooklyn Eagle</i>, which was published Feb. 3, giving my +views in relation to cometary phenomena. With this I might remain +satisfied, were it not that the interesting paper by G. D. Hiscox, +published in the SCIENTIFIC AMERICAN SUPPLEMENT, Feb. 16, impressed +me with the idea that the theory I advanced might assist in +explaining others, if brought to the notice of those interested +through the columns of your valuable journal.</p> + +<p>The theory that I advance to account for the several phenomena +relating to comets' tails is, that comets are non-luminous, +transparent bodies; that they transmit the light of the sun; that +the transmitted light reflected by the particles of matter in space +constitutes the tails of comets. "Like causes produce like +effects." By contraries, then, like effects must be produced by +similar causes; for, if an effect produced by a cause which is +known is similar to an effect produced by a cause which is not +known, the cause which is known must be similar to the cause which +is not known. This is true or not.</p> + +<p>I submit the following experiments to substantiate the theory +advanced.</p> + +<p>Partially fill a vial or a tumbler with water, hold it by the +rim, and move it around a lighted candle placed upon a table. A +shadow surrounding the transmitted light will be cast upon the +table. As the tumbler approaches the light, the shadow follows the +tumbler, and when receding the tumbler follows the shadow; and as +the tumbler is moved around the light, the shadow will swing round +from one side to the other. If the tumbler be held so that a puff +of smoke can be blown into the transmitted rays, the particles of +smoke will reflect the transmitted light, and will illustrate my +idea of what constitutes a comet's tail. A dark band may be +observed in this stream of light, as also in the light cast upon +the table.</p> + +<p>In these experiments, we see the effects produced by a cause +which is known; the effects are similar to those observed in the +tails of comets, the cause of which we do not know; but is it not +reasonable to assume that the cause is similar?</p> + +<p>Assuming now that comets are transparent, can any other +phenomena peculiar to comets be accounted for upon this hypothesis? +Next to the tail itself, the curve is the most noticeable feature, +and if we consider the extraordinary length of these appendages, +the astounding velocity at which comets move in their orbits, and +the time that would elapse before a ray of light, emitted from the +nucleus, would reach the end of the tail, perhaps the curve--which, +if I am not deceived in my observations, always dips toward its +orbit--can be accounted for. If a comet moved in a direct line +toward the center of the sun, there would be no curve to the tail. +But taking Donati's comet of 1858 as an example, the tail of which +was said to be about 200,000,000 miles long, a ray of light +traveling at the rate of 192,000 miles per second would be about +twenty minutes in going from the nucleus to the end of the +tail.</p> + +<p>But during that time the comet would move in its orbit, say, +50,000 miles, and as light moves in a straight line, and other rays +are constantly emerging from the nucleus as it moves along in its +course, the result is that the tail has a curved appearance.</p> + +<p>I have no data at hand regarding this comet, but what I have +said will serve to illustrate my ideas. Again, referring to this +comet, I remember to have read the statement of an astronomer that, +after passing round the sun, a new tail was formed opposite the +original one. Now, it seems to me that that is just what would +happen, for in moving round the sun the comet would travel say +3,000,000 miles; the greater portion of the tail then, would extend +millions of miles upon one side of the sun, while from the nucleus +upon the opposite side of the sun a new tail would appear to be +formed.</p> + +<p>Upon this hypothesis, the extraordinary length of their tails +and the fact that stars are visible through the densest portion of +them is explained; as also the fact that they so rapidly disappear +from view when moving from the sun, the light received by them from +the sun being in proportion to their distance from it, and but +little of that reflected.</p> + +<p>JOHN M. HUGHES.</p> + +<p>Brooklyn, N. Y.</p> + +<hr> +<p>[FOR THE SCIENTIFIC AMERICAN.]</p> + +<p><a name="23"></a></p> + +<h2>ON COMETS.</h2> + +<p>When we see a comet approaching the sun with its tail following +in the orbit of the nucleus, we have no great difficulty in +believing the common theory that a comet consists of nucleus +attracted toward the sun, while the tail is repelled; and that we +see the whole of it. But as it approaches the sun, difficulties +arise that make us doubt whether the theory be true.</p> + +<p>Let us suppose a comet with a tail 50,000,000 miles in length, +and that it will require two days to pass round the sun. Now the +tail, being always in a line drawn through the center of the sun +and center of the nucleus, will, when it reaches the long axis of +the elliptical orbit, stand perpendicularly to the orbit of the +nucleus. That is, the extremity of the tail farthest from the sun, +in addition to its onward motion, has acquired a lateral motion +that has lifted it 50,000,000 miles in the first day of its +perihelion. The velocity of the extremity has been vastly +accelerated over that of the nucleus, and it has moreover a sheer +lift above the orbit of the nucleus. Now this lift is in opposition +to gravity; neither is it in consequence of any previous momentum, +for its velocity is accelerated and its previous momentum would be +a hindrance; nor is the lift in consequence of any repelling force +from the sun, for such force would be diminished in proportion to +the square of the distance, and the far end would be acted on less +than the nucleus end of the tail, whereas the velocity of the +former is increased a hundred fold over that of the latter. A polar +force in the comet would merely draw the comet into the sun. We +therefore find no force adequate for such a lift, but on the +contrary all the forces are opposed to it.</p> + +<p>But if the first day of the perihelion overwhelms us with +difficulty, the second day will prove disastrous to the common +theory. For the extremity of the tail farthest from the sun will be +required to pass with lateral motion from its perpendicular +100,000,000 miles, so that it may be in advance of the nucleus and +again rest on its orbit. This orbit is an impassable line, and +therefore instantly arrests the prodigious lateral velocity of the +tail. That impassable orbital line is to it as solid and inflexible +as a wall of adamant. The motion so instantly arrested would be +disastrous to any tail, whether composed of gas, meteorites, or +electricity, whatever that may be.</p> + +<p>Having shown that the common theory of comets is filled with +insuperable difficulties, I will again call attention to a theory +proposed about eighteen months ago in the SCIENTIFIC AMERICAN.</p> + +<p>According to this theory, a comet consists of a nucleus and an +atmosphere, for the most part invisible, surrounding it on all +sides to an extent at least equal to the length of the tail. The +rays of the sun in passing through or near the nucleus are so +modified as to become visible in their further progress through the +cometic atmosphere, while all the rest remain invisible. What we +call the tail is merely a radius of the cometic atmosphere made +visible, and as the comet moves through space, only different +portions of the atmosphere come in sight, in obedience to the +ordinary laws of light. There is no difficulty in accounting for +the rise and fall of the tail at perihelion, nor for the tail +preceding the nucleus afterward.</p> + +<p>The spherical theory accounts easily for the different forms of +tail seen in different comets. The sword shaped tails, at variance +with the common theory, can be accounted for by supposing a slight +difference in density or material in the cometic atmosphere, which +will deflect the light as seen. The comet of 1823, which cannot be +explained on the common theory, is very easily explained on the +spherical. That comet showed two tails, apparently of equal length, +which moved opposite to each other, and perpendicularly to the +orbit of the nucleus, and showing no signs of repulsive force from +the sun. On the spherical theory it is only necessary to suppose +such an arrangement of the nucleus as would reflect the rays of the +sun laterally; a slight modification of the nucleus would give not +only two but any number of tails pointing in different +directions.</p> + +<p>It may be objected to the spherical theory that a tail +50,000,000 miles long would call for a sphere 100,000,000 miles in +diameter, and that would be too vast for our solar system. But it +is claimed for this sphere that it consists of the same material as +the so-called tail, and that it has the same capability of moving +among planets without manifest disturbance to either.</p> + +<p>The sphere at the perihelion would envelop the sun, and as a +noticeable reduction is sometimes found in its so-called tail, the +cometic atmosphere may impart to the sun at that time whatever is +necessary to its use.</p> + +<p>That there is something in common between the sun's corona and +cometary matter was shown by the last solar eclipse observed in +South Pacific Ocean, where the spectrum of sun's corona was found +to be the same as that of a comet's tail. Are we to attribute in +any degree the different appearances of the sun's corona to the +presence or absence of a comet at its perihelion? At the eclipse of +the sun seen in Upper Egypt two or three years ago, a comet was +seen close to the sun, but I have seen no account of the appearance +of the corona at that time.</p> + +<p>FURMAN LEAMING, M.D.</p> + +<p>Romney, Tippecanoe Co. Indiana.</p> + +<hr> +<p><a name="26"></a></p> + +<h2>FORMS OF IVY.</h2> + +<p>It is scarcely possible for us to bee too emphatic in our +praises of the most distinct forms of ivy, since but few other +hardy climbing plants ever give to us a tithe of their freshness +and variety. A good long stretch of wall covered with a selection +of the best green-leaved kind is always interesting, and never more +so than during the winter months, especially if at intervals the +golden Japanese jasmine is planted among them or a few plants of +pyracantha or of Simmon's cotoneaster for the sake of their coral +fruitage. The large-leaved golden ivy is also very effective here +and there along a sunny wall, especially if contrasted with the +small-leaved kind--atropurpurea--which has dark purple or bronzy +foliage at this season. Of the large-leaved kinds, one of the most +distinct is canariensis, or large-leaved Irish ivy, and Raegner's +variety, with leathery, heart-shaped foliage, is also handsome. The +birdsfoot ivy (pedata) is curious, as it clings to the stones like +delicate leaf embroidery, and for shining green leafage but few +equal to the one called lucida. The two other kinds sketched are +hastata and digitata, both free growing and distinct sorts.</p> + +<p class="ctr"><a href="images/15a.png"><img src= +"images/15a_th.jpg" alt=""></a></p> + +<p class="ctr">VARIOUS FORMS OF IVY.<br> +Heart-leaved Ivy (Hedera Raegenerana).<br> +Glossy Ivy (H. lucida).<br> +Arrow-leaved Ivy (H. hastata).</p> + +<p><i>Ivy Leaves</i>.--Common ivy is tolerably plentiful nearly +everywhere, but it is not common to find a good distinct series of +its many varieties even in the best gardens. Of all the different +forms of ivy, I think the large-leaved golden one of the best; +certainly the best of the variegated kinds. Raegner's variety is +also very bold, its great glossy, heart-shaped leaves most +effective. Algeriensis is another fine-leaved kind, the form +dentata producing foliage even still larger when well grown. For +making low evergreen edgings on the turf, for carpeting banks, the +covering of bare walls and the old tree stumps, we have no other +evergreen shrub so fresh and variable, or so easily cultivated as +are these forms of the ivy green. Perhaps one reason why the finer +kinds of ivy are comparatively uncommon is the fact that a strong +prejudice exists against ivy in many minds. It is an erroneous +notion that ivy injures buildings against the walls of which it is +planted; it never injures a good wall, nor a sound house, but on +the contrary, hides and softens the stony bareness of the one and +adds beauty and freshness to the other.--<i>The Garden</i>.</p> + +<p class="ctr"><a href="images/15b.png"><img src= +"images/15b_th.jpg" alt=""></a></p> + +<p class="ctr">VARIOUS FORMS OF IVY.<br> +Finger-leaved Ivy (H. Itata).<br> +Irish Ivy (H. canariensis).<br> +Rira's foot Ivy (H. pedata).</p> + +<hr> +<p><a name="27"></a></p> + +<h2>PROPAGATING ROSES.</h2> + +<p>In an article on this subject an English horticultural journal +describes the method pursued by a London florist. After stating +that out of a case containing 310 cuttings only five failed to +root, the article proceeds: The case or box is made of common rough +deal boards. It is five feet six inches long and one foot in depth. +Within half an inch of the top a groove is cut inside the box, into +which the glass is slid, after the manner of a sliding box lid. In +the end of the third week in July the box was placed in the kitchen +garden under the shadow of a high north wall; it was then about +half filled with good turfy loam, to which had been added a little +leaf mould and a good sprinkling of sharp sand. The soil was then +pressed down very firmly (the box being nearly half full when +pressed), and then thoroughly well soaked with rain water, and +allowed to stay uncovered until the next day. The next day good +stout cuttings were taken of all the roses, both tea and hybrid +perpetual, which it was desired to add to the stock. They were then +inserted closely and firmly in the soil, just over the bottom leaf, +the glasses were slipped on and puttied down; the grooves in which +the glass slid, and even the joints in the glass, being filled with +putty, so as to exclude the air. The whole thing completed, nothing +more remained to be done but to leave the box in its cool, shady +nook for five or six weeks, when the growing points of the free +starting kinds gave notice that the glasses might be removed, a bit +at a time, with safety. Nothing could be more simple, or demand +less skill, and the operation may be carried out successfully by an +amateur at any time during the season, when good firm cuttings can +be got, and when six weeks' tolerably fine weather may be counted +on. The success of the whole thing depends on having the glasses +fixed so that they may not be removed until the cuttings are +rooted, and in placing the boxes in a shady place. So treated, +carnations and many of our shrubs and herbaceous perennials may be +propagated by unskilled persons with certainty, and without much +trouble.</p> + +<hr> +<p><a name="28"></a></p> + +<h2>A FEW OF THE BEST INULAS.</h2> + +<p>Of the fifty-six species of Inula described in scientific works, +probably not more than thirty are at present in cultivation in this +country, and those are chiefly confined to botanic gardens, +notwithstanding the fact that many of them are useful garden +plants. They are principally distributed throughout Southern +Europe, although we find them extending to Siberia and the +Himalayas; indeed, it is to the Himalayas we are indebted for the +kinds that are most ornamental. Some of the low-growing species are +extremely useful for the rockery, such as I. montana (the Mountain +Inula), a fine dwarf plant with woolly lanceolate leaves and dense +heads of orange-colored flowers, resembling in habit and general +appearance some of the creeping Hieraciums. It is a handsome and +desirable plant for the decoration of old walls and similar places, +where it can be a little sheltered from rain and drip. Another very +useful species for this purpose is I. rhizocephaloides, found +plentifully in the Himalayas. It is one of the prettiest Alpine +composites we have. It seldom attains more than from one inch to +two inches in height, forming a dense rosette of short, hairy, oval +leaves, in the center of which the bright purple involucres, in the +form of a ball, are extremely interesting. It is easily cultivated, +requiring, however, a rather snug nook, where it will not be +allowed to become too dry. It is best propagated from seed. Then +there is the woolly Inula (I. candida), a pretty plant with small +oval leaves, covered with a thick, silky down, and much in the way +of the white-leaved I. limonifolia, both of which are very +effective when grown in masses, which should always be low down +near the front of a rockery, or as an edging for a mixed border. +The glandular-leaved Inula (I. glandulosa), of which a good +representation is here given, is a beautiful hardy perennial. It is +a native of Georgia and the Caucasian Alps, near the Caspian Sea. +It is a rather robust-growing species, with large, bright, +orange-yellow flowers, varying from three to five inches in +diameter, the narrow and very straggly ray florets contrasting +nicely with the rather prominent disk. The leaves, although quite +entire, seem notched, owing to large black glands which form on +their margins. They are lanceolate, and clasp the stem. The plant +is very variable, both as regards robustness and size of flowers, +and this may in a measure account for the confusion existing +between it and I. Oculus-Christi.</p> + +<p>The soil most suitable for the full development of I. glandulosa +is a strong, clayey, retentive loam; it does not thrive well in the +light shallow soils in the neighborhood of London, except in shady +positions. I. Hookeri is a free-flowering perennial, with pointed +lanceolate leaves, of a delicate texture, bright green, and very +finely toothed. The flowers, which are sweet-scented, are not so +large as those of I. glandulosa, and are produced singly, the ray +florets being, however, much more numerous, rarely numbering less +than thirty. It is found in abundance in rocky places in Sikkim, +where it replaces the nearly allied I. grandiflora, a dwarfer +species, with much shorter, shining leaves; both are very desirable +plants either for rockery or flower border work. The Elecampane (I. +Helenium) is an imposing, robust-growing species, having large, +broad leaves a foot or more in length. It grows from four feet to +five feet in height, and its thick, shaggy branches are crowned +with large yellow flowers. For isolating in woods this plant, is +very useful, and with the exception of Telekia cordifolia, it would +be hard to find a rival to it. It is, I believe, pretty extensively +used for planting in shrubberies, but unless they are thin and open +it is seldom seen to advantage. It is found wild or naturalized in +some parts of England. It flowers in June and July, and even into +August when the season has been favorable.</p> + +<p class="ctr"><img src="images/15c.png" alt= +"INULA GLANDULOSA (<i>flowers deep yellow</i>.)"></p> + +<p class="ctr">INULA GLANDULOSA (<i>flowers deep yellow</i>.)</p> + +<p>For naturalizing in woods the following will be found useful, +<i>viz</i>., I. salicina, I. Oculus-Christi, I. squarrosa, I. +britannica, and many more, the true beauty of which can only be +realized in this way. With the exception of I. rhizocepbaloides, +they are all propagated by division with the greatest ease, or by +seed, which is best sown as soon as it is ripe.--<i>D.K., The +Garden</i>.</p> + +<hr> +<p><a name="29"></a></p> + +<h2>FRUIT GROWING.</h2> + +<h3>By P.H. FOSTER.</h3> + +<p>In the first place, if you contemplate appropriating a portion +of your land for the raising of fruits, you should have the orchard +so situated that no large animals can run at large on the grounds. +Prepare your soil in the most thorough manner; underdrain, if +necessary, to carry off surplus water; dig deep, large holes; fill +in the bottom with debris; in the very bottom put a few leaves, +clam and oyster shells, etc., then sods; above and below the roots +put a good garden or field soil; do not give the trees fresh manure +at the time of setting, but the following fall manure highly with +any kind on top of the ground; dig it in the following spring; keep +the soil frequently worked during the summer, and, if convenient, +mulch with hay, straw, or leaves.</p> + +<p>Now you are on the road to progress, provided you have made no +mistake in the selection of your trees. The purposes for which you +intend your fruit is highly important. You should well consider at +the outset if for family or market use. This is a business which +requires a long look ahead, for it is said, "He who plants pears +looks ahead for his heirs."</p> + +<p>Caution should be used in procuring your stock; little should be +planted that is not fairly tested on the Island, purchased of +parties who can be fully relied upon to give you what you want. Do +not buy your stock of parties who carry labels in their pockets to +make to order what you want out of the same bundle of trees.</p> + +<p>Now, having your trees set out in a proper manner, of such +varieties as you desire, the next important step is to bring the +trees into usefulness. My plan is to use bone--fine bone--very +freely about every three years. Another important matter is that of +trimming. "Fire purifies," and the knife regulates the grand +balance or equilibrium between roots and tops. In most cases the +top outgrows the roots, the consequence of which is an ultimate +weakness of the tree. It is thrown into excessive fruiting, +disease, and premature decay. To avoid this result, use the knife +when required. Thin out the inside branches when small, and if the +tree does not make a satisfactory growth, cut back half way to the +ground.</p> + +<p>We will suppose that you have got your trees growing nicely, and +they have begun to bear fruit. There are other important steps to +be taken, which will be of little cost to you. Provide a wind-break +for the orchard. Evergreens answer the purpose, being a protection +against the wind. Having this matter attended to, there are other +enemies with which we must contend. I refer to the apple and peach +tree borers. The former will live in the tree for three years, if +unmolested; the latter, one year only. They are very easily +destroyed by looking over the trees and taking them out with a +knife; or maybe prevented from touching the trees by wrapping a +piece of felt paper, 8 inches wide, around the tree near the +ground, the bottom being covered with dirt and the top tied tightly +above. The pear is not generally disturbed by these insects--only +the apple, peach, and quince. We have another insect very +destructive to the plum, peach, cherry, and apple--the +<i>curcutio</i>, or plum weavel. This season for the first time in +twenty years we have gathered a small crop of that very desirable +plum, the Purple Favorite. We simply threw air-slaked lime over the +trees nearly every morning for from four to six weeks, from the +time the tree was out of bloom. Peach trees should be treated in +the same manner. Another method of fighting this insect is to +spread a sheet under the tree, and with a blow jar off the little +Turk and secure him on the sheet. But I consider the lime procedure +the less trouble and more effective. The tent caterpillar, which is +easily seen, should be destroyed at once. We have yet another +insect to contend with which infests the apple and pear, commonly +called the Coddling Moth, and the larva, the apple-worm +(<i>Garpocapsa pomonella</i>). The loss by the ravaaes of this +insect alone to the fruit growers of the United States fan hardly +be estimated, as in many cases the whole crop is rendered +worthless. Such a vast destruction of two of the most valuable +fruits the world produces should stimulate scientists in this age +of progress to discover an effectual remedy against such a gigantic +evil.</p> + +<p>I have never yet discovered nor tried an effectual remedy +against this insect. The nearest I have approached his +extermination is in the following manner: After it has entered the +fruit and accomplished its damage, the time arrives when it has to +leave the fruit and hide itself in a quiet, secure position to +undergo the transition from the larva to the pupa state, which +requires, in the early part of the season, eight or ten days; after +this time the miller is hatched and is again ready to besiege the +fruit with its sting. The insect, being two-brooded in this climate +at least, if not disturbed, has an aggregating force to do mischief +the second time. The progeny for the succeeding year have alone to +depend on the security of this second generation of larvæ. As +they may often be found in bark of apple trees during winter, my +plan of destruction is, about the first of July to take woolen rags +long enough to wrap around the trees, and say four inches wide. +Each week I look over the trees, and destroy the worms secreted +under the rags and wherever I find them until the fruit is off the +trees. I have all the green fruit, of every kind, carefully picked +up as soon as it falls, thereby destroying many of the curculio as +well as the apple-worms.</p> + +<p>One word upon the grape--the insect part of the question. The +<i>Phylloxera vastatrix</i>, or grape-vine louse, is already at +work on Long Island. It is found very difficult to raise many of +our fine, new grapes with us in consequence of the depredations of +this very minute insect, it being almost too small to be seen by +the naked eye. There has lately been discovered a remedy which is +entirely chemical and as yet but little disseminated. Very soon, no +doubt, a discovery will be made that will stay the progress of this +destructive enemy.</p> + +<p>We should plant aplenty of cherry and small fruit trees to yield +feed for birds. In return they will assist us in our efforts to +preserve a bountiful supply of this health producing element.</p> + +<hr> +<p><a name="25"></a></p> + +<h2>COARSE FOOD FOR PIGS.</h2> + +<p>A recent subscriber wants advice how to feed pigs of 25 to 35 +pounds weight, that are to be kept over winter and fitted for sale +at about six months old--whether coarse food will not help them as +much in winter as in summer. How roots and pumpkins will answer in +lieu of grass, and what can be fed when this green food is gone? He +has had poor success in growing young pigs on corn alone. He has a +reasonably warm pen for winter.</p> + +<p>The question of food is constantly recurring, and this is one of +the best evidences of the advancement of the country in the +feeder's art. When people are making no inquiry as to improved +methods in any direction, no progress can be made. There has been +more progress made in the philosophy of feeding during the last +thirty years than in the century and a half previous.</p> + +<p>In pig feeding in the dairy districts, young pigs generally grow +up in a very healthy condition, owing to the refuse milk of the +dairy, which furnishes the principal food of young pigs. Skim-milk +contains all the elements for growing the muscles and bones of +young pigs. This gave them a good, rangy frame, and, when desired, +could be fed into 400 or 500 pounds weight. But the fault attending +this feeding was, that it was too scanty to produce such rapid +growth as is desired. It took too long to develop them for the best +profit. It had not then been discovered by the farmer that it costs +less to put the first hundred pounds on the pig than the second, +and less for the second than the third, etc.; that it was much +cheaper to produce 200 pounds of pork in six months than in nine +and twelve months. When it became evident that profit required more +rapid feeding, then they began to ply them continually with the +most concentrated food--corn meal or clear corn. If this was fed in +summer, on pasture, no harm was observed, for the grass gave bulk +in the stomach, and the pigs were were healthy and made good +progress. But if the young pigs were fed in pen in winter upon corn +meal or clear corn, the result was quite different; this +concentrated food produced feverish symptoms, and the pigs would +lose their appetite for a few days, drinking only water, which, +after a while, would relieve the stomach, and the pigs would eat +vigorously again. Now, had they been fed a few quarts of turnips, +carrots, beets, or pumpkins, to give bulk to the stomach, and +separate the concentrated food, no harm would have come. This gives +the gastric juice a free circulation through the contents of the +stomach, the food is properly digested and applied to the needs of +the body instead of causing fever by remaining in the +stomach.--<i>Live Stock Journal</i>.</p> + +<hr> +<p><a name="33"></a></p> + +<h2>METE KINGI.</h2> + +<p>Our engraving is a portrait of a familiar character in New +Zealand, chief Mete Kingi, who recently died at the age of one +hundred years. He was a fine specimen of the Maori race, the native +New Zealanders, a branch of the Malayo-Polynesian family. The New +Zealanders surpassed all other people in the art of tattooing, to +which their chiefs gave especial attention. Mete Kingi, as our +picture shows, was no exception. Tattooing on the face they termed +<i>moko</i>. The men tattoo their faces, hips, and thighs; the +women their upper lips; for this purpose charcoal made from kauri +gum is chiefly used. It has the blue color when pricked into the +skin, growing lighter in shade in the course of years. The subject +of our illustration embraced Christianity, and was much respected. +Our engraving is from the <i>Illustrated Australian News</i>.</p> + +<p class="ctr"><img src="images/16a.png" alt= +"THE LATE MAORI CHIEF METE KINGI."></p> + +<p class="ctr">THE LATE MAORI CHIEF METE KINGI.</p> + +<hr> +<h2>LAKE TAHOE.</h2> + +<p>Some very interesting information by Prof. John Le Conte, is +given in the <i>Overland Monthly</i>, being the result of some +physical observations made by the author at Lake Tahoe, in 1873. +Lake Tahoe, also called Lake Bigler, is situated at an altitude of +6,247 feet in the Sierra Nevada Mountains, partly in California, +partly in Nevada. The lake has a length of 22 and a width of 12 +miles. As regards its origin, the author regards it as a "plication +hollow," or a trough produced by the formation of two mountain +ridges, afterward modified by glacial agency. The depth of the lake +is remarkable; the observations taken at ten stations along the +length of the lake gave the following depths in feet: 900, 1,385, +1,495, 1,500, 1,506, 1,540, 1,504, 1,600, 1,640, 1645. This depth +exceeds that of the Swiss lakes proper--Lake Geneva, for example, +has a maximum depth of 1,096 feet--but is considerably less than +that of Lakes Maggiore and Como, on the Italian side of the Alps. A +series of observations of the temperature of the water were taken +between the 11th and 18th of August. The average corrected results +are as follows:</p> + +<pre> + Depth in feet. Temp. (C.) + 0(surface).................................19.4 + 50..........................................17.2 + 100..........................................12.8 + 150..........................................10.0 + 200.......................................... 8.9 + 250.......................................... 8.3 + 300.......................................... 7.8 + 330 (bottom)................................. 7.5 + 400.......................................... 7.2 + 480 (bottom)................................. 6.9 + 500.......................................... 6.7 + 600.......................................... 6.1 + 772 (bottom)................................. 5.0 + 1506 (bottom)..............,.................. 4.0 +</pre> + +<p>The temperature, therefore, diminishes with increasing depth to +about 700 or 800 feet, and below this remains sensibly the same +down to 1,506 feet; or in other words, a constant temperature of +4° C. prevails at all depths below about. 820 feet. This is in +accordance with the theory, the temperature named being that of the +maximum density of water, and it confirms the recent observations +of Prof. Forel in Switzerland; he found, for example, that a +constant temperature of 4° C. was reached in Lake Zurich at a +depth of nearly 400 feet, the lake being then covered with 4 inches +of ice. The explanation of the observed fact that Lake Tahoe does +not entirely freeze over even in severe winters is found in the +extreme depth; and the fact that the bodies of drowned persons do +not rise to the surface after the lapse of the usual time is +explained by the low temperature prevailing near the bottom, which +does not allow the necessary decomposition to go forward so as to +produce the ordinary result.</p> + +<p>The water of Lake Tahoe is remarkable both for its transparency +and beauty of color. A series of observations made at the close of +August or beginning of September showed that a horizontally +adjusted dinner plate of about 9½ inches diameter was +visible at noon at a depth of 108 feet. The maximum depth of the +limit of visibility as found by Prof. Forel, in Lake Geneva, was 56 +feet. He showed, moreover, that this limit is much greater in. +winter than in summer, as explained in part by the greater absence +of suspended matter and in part by the fact that increase of +temperature increases the absorbing power of water for light. The +maximum depth of visibility in the Atlantic Ocean, as found by +Count de Pourtales, was 162 feet, and Prof. Le Conte states his +belief that winter observations in Lake Tahoe would place the limit +at even a greater depth than this. The author gives a detailed and +interesting discussion in regard to the blue color of lake waters, +reviewing in full the results of previous writers on the subject, +and concludes that while pure water unquestionably absorbs a larger +part of the red end of the spectrum, and hence appears blue by +transmitted light, the color seen by diffuse reflection is mainly +due to the selective reflection from the fine particles suspended +in it.</p> + +<p>The last subject discussed by the author is that of the +rhythmical variations of level, or "seiches," of deep lakes; he +applies the usual formula to Lake Tahoe, and calculates from it the +length of a complete longitudinal and of a transverse "seiche;" +these are found to be eighteen or nineteen minutes in the first +case and thirteen minutes in the second.</p> + +<hr> +<p>A catalogue, containing brief notices of many important +scientific papers heretofore published in the SUPPLEMENT, may be +had gratis at this office.</p> + +<hr> +<h2>THE SCIENTIFIC AMERICAN SUPPLEMENT.</h2> + +<h3>PUBLISHED WEEKLY.</h3> + +<p><b>Terms of Subscription, $5 a Year.</b></p> + +<p>Sent by mail, postage prepaid, to subscribers in any part of the +United States or Canada. Six dollars a year, sent, prepaid, to any +foreign country.</p> + +<p>All the back numbers of THE SUPPLEMENT, from the commencement, +January 1, 1876, can be had. Price, 10 cents each.</p> + +<p>All the back volumes of THE SUPPLEMENT can likewise be supplied. +Two volumes are issued yearly. Price of each volume, $2.50, +stitched in paper, or $3.50, bound in stiff covers.</p> + +<p>COMBINED RATES--One copy of SCIENTIFIC AMERICAN and one copy of +SCIENTIFIC AMERICAN SUPPLEMENT, one year, postpaid, $7.00.</p> + +<p>A liberal discount to booksellers, news agents, and +canvassers.</p> + +<p><b>MUNN & CO., Publishers,</b></p> + +<p><b>361 Broadway, New York, N. Y.</b></p> + +<hr> +<h2><b>PATENTS.</b></h2> + +<p>In connection with the <b>Scientific American</b>, Messrs. MUNN +& Co. are Solicitors of American and Foreign Patents, have had +39 years' experience, and now have the largest establishment in the +world. Patents are obtained on the best terms.</p> + +<p>A special notice is made in the <b>Scientific American</b> of +all Inventions patented through this Agency, with the name and +residence of the Patentee. By the immense circulation thus given, +public attention is directed to the merits of the new patent, and +sales or introduction often easily effected.</p> + +<p>Any person who has made a new discovery or invention can +ascertain, free of charge, whether a patent can probably be +obtained, by writing to MUNN & Co.</p> + +<p>We also send free our Hand Book about the Patent Laws, Patents, +Caveats. Trade Marks, their costs, and how procured, with hints for +procuring advances on inventions. Address</p> + +<p><b>MUNN & CO., 361 Broadway, New York.</b></p> + +<p>Branch Office, cor. F and 7th Sts., Washington, D. C.</p> + + + + + + + + +<pre> + + + + + +End of the Project Gutenberg EBook of Scientific American Supplement, No. +433, April 19, 1884, by Various + +*** END OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN SUPPL., NO. 433 *** + +***** This file should be named 9076-h.htm or 9076-h.zip ***** +This and all associated files of various formats will be found in: + http://www.gutenberg.org/9/0/7/9076/ + +Produced by J. Niehof, D. Kretz, J. Sutherland, and +Distributed Proofreaders + + +Updated editions will replace the previous one--the old editions +will be renamed. + +Creating the works from public domain print editions means that no +one owns a United States copyright in these works, so the Foundation +(and you!) can copy and distribute it in the United States without +permission and without paying copyright royalties. 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files differnew file mode 100644 index 0000000..2089ef7 --- /dev/null +++ b/9076-h/images/9b.png diff --git a/9076.txt b/9076.txt new file mode 100644 index 0000000..8dc4bea --- /dev/null +++ b/9076.txt @@ -0,0 +1,4272 @@ +The Project Gutenberg EBook of Scientific American Supplement, No. 433, +April 19, 1884, by Various + +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: Scientific American Supplement, No. 433, April 19, 1884 + +Author: Various + +Posting Date: October 10, 2012 [EBook #9076] +Release Date: October, 2005 +First Posted: September 3, 2003 + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN SUPPL., NO. 433 *** + + + + +Produced by J. Niehof, D. Kretz, J. Sutherland, and +Distributed Proofreaders + + + + + + + + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 433 + + + + +NEW YORK, APRIL 19, 1884 + +Scientific American Supplement. Vol. XVII, No. 433. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + + * * * * * + +TABLE OF CONTENTS. + +I. CHEMISTRY, METALLURGY, ETC.--New Analogy between + Solids, Liquids, and Gases. + + Hydrogen Amalgam. + + Treatment of Ores by Electrolysis.--By M. KILIANI. + +II. ENGINEERING, AND MECHANICS.--Electric Railway at Vienna.--With + engraving. + + Instruction in Mechanical Engineering.--Technical and trade + education.--A course of study sketched out.--By Prof. R.H. + THURSTON. + + Improved Double Boiler.--3 figures. + + The Gardner Machine Gun.--With three engravings showing the + single barrel, two barrel, and five barrel guns. + + Climbing Tricycles. + + Submarine Explorations.--Voyage of the Talisman.--The Thibaudier + sounding apparatus.--With map, diagrams, and engravings. + + Jamieson's Cable Grapnel.--With engraving. + + A Threaded Set Collar. + +III. TECHNOLOGY.--Wretched Boiler Making. + + Pneumatic Malting.--With full description of the most improved + methods and apparatus.--Numerous figures. + + Reducing and Enlarging Plaster Casts. + + Stripping the Film from Gelatine Negatives. + +IV. ELECTRICITY.--Non-sparking Key. + + New Instruments for Measuring Electric Currents and Electromotive + Force.--By MESSRS. K.E. CROMPTON and GISBERT + KAPP.--Paper read before the Society of Telegraph Engineers.--With + several engravings. + + When Does the Electric Shock Become Fatal? + +V. ART AND ARCHAEOLOGY.--Robert Cauer's Statute of Lorelei.--With + engraving. + + The Pyramids of Meroe.--With engraving. + +VI. ASTRONOMY AND METEOROLOGY.--The Red Sky.--Cause of + the same explained by the Department of Meteorology. + + A Theory of Cometary Phenomena. + + On Comets.--By FURMAN LEAMING, M.D. + +VII. NATURAL HISTORY.--The Prolificness of the Oyster. + + Coarse Food for Pigs. + +VIII. BOTANY, HORTICULTURE, ETC.--Forms of Ivy.--With + several engravings. + + Propagating Roses. + + A Few of the Best Inulas.--With engraving. + + Fruit Growing.--By P.H. FOSTER. + +IX. MEDICINE, HYGIENE, ETC.--A People without Consumption, + and Some Account of Their Country, the Cumberland Tableland. + --By E.M. WIGHT. + + The Treatment of Habitual Constipation. + +X. MISCELLANEOUS.--The French Scientific Station at Cape Horn. + +XI. BIOGRAPHY.--The Late Maori Chief, Mete Kingi.--With portrait. + + * * * * * + + + + +THE FRENCH SCIENTIFIC STATION AT CAPE HORN. + + +In 1875 Lieutenant Weyprecht of the Austrian navy called the attention +of scientific men to the desirability of having an organized and +continual system of hourly meteorological and magnetic observations +around the poles. In 1879 the first conference of what was termed the +International Polar Congress was held at Hamburg. Delegates from eight +nations were present--Germany, Austria, Denmark, France, Holland, +Norway, Russia, and Sweden. + +The congress then settled upon a programme whose features were: 1. To +establish general principles and fixed laws in regard to the pressure +of the atmosphere, the distribution and variation of temperature, +atmospheric currents, climatic characteristics. 2. To assist the +prediction of the course and occurrence of storms. 3. To assist the +study of the disturbances of the magnetic elements and their relations +to the auroral light and sun spots. 4. To study the distribution of +the magnetic force and its secular and other changes. 5. To study the +distribution of heat and submarine currents in the polar regions. 6. To +obtain certain dimensions in accord with recent methods. Finally, to +collect observations and specimens in the domain of zoology, botany, +geology, etc. + +The representatives of the various nations had several conferences +later, and by the 1st of May, 1881, there were sufficient subscribers to +justify the establishment of eight Arctic stations. + +France entered actively in this work later, and its first expedition was +to Orange Bay and Cape Horn, under the surveillance and direction of +the Academy of Sciences, Paris, and responsible to the Secretary of the +Navy. On the 6th of September, 1882, this scientific corps established +itself in Orange Bay, near Cape Horn, and energetically began its +serious labors, and by October 22 the greater part of their preliminary +preparations was completed, comprising the erection of a magnetic +observatory, an astronomic observatory, a room for the determination of +the carbonic anhydride of the air, another for the sea register, and +a bridge 92 feet long, photographic laboratory, barometer room, and +buildings for the men, food, and appurtenances, together with a +laboratory of natural history. + +In short, in spite of persistent rains and the difficulties of the +situation, from September 8 to October 22 they erected an establishment +of which the different parts, fastened, as it were, to the flank of a +steep hill, covered 450 square meters (4,823 square feet), and rested +upon 200 wooden piles. + +From September 26, 1882, to September 1, 1883, night and day +uninterruptedly, a watch was kept, in which the officers took part, so +that the observations might be regularly made and recorded. Every four +hours a series of direct magnetic and meteorological observations was +made, from hour to hour meteorological notes were taken, the rise and +fall of the sea recorded, and these were frequently multiplied by +observations every quarter of an hour; the longitude and latitude were +exactly determined, a number of additions to the catalogue of the fixed +stars for the southern heavens made, and numerous specimens in natural +history collected. + +The apparatus employed by the expedition for the registration of the +magnetic elements was devised by M. Mascart, by which the variations +of the three elements are inscribed upon a sheet of paper covered with +gelatine bromide, inclination, vertical and horizontal components, with +a certainty which is shown by the 330 diurnal curves brought back from +the Cape. + +The register proper is composed of a clock and a photographic frame +which descends its entire length in twenty-four hours, thus causing the +sensitized paper to pass behind a horizontal window upon which falls the +light reflected by the mirrors of the magnetic instruments. One of those +mirrors is fixed, and gives a line of reference; the other is attached +to the magnetic bar, whose slightest movements it reproduces upon the +sensitized paper. The moments when direct observations were taken were +carefully recorded. The magnetic _pavilion_ was made of wood and copper, +placed at about fifty-three feet from the dwellings or camp, near the +sea, against a wooded hill which shaded it completely; the interior +was covered with felt upon all its sides, in order to avoid as much as +possible the varying temperatures. + +The diurnal amplitude of the declination increased uniformly from the +time of their arrival in September up to December, when it obtained +its maximum of 7'40", then diminished to June, when it is no more than +2'20"; from this it increased up to the day of departure. The maximum +declination takes place toward 1 P.M., the minimum at 8:50 A.M. The +night maxima and minima are not clearly shown except in the southern +winter. + +The mean diurnal curve brings into prominence the constant diminution +of the declination and the much greater importance of the perturbations +during the summer months. These means, combined with the 300 absolute +determinations, give 4' as the annual change of the declination. + +M. Mascart's apparatus proved to be wonderfully useful in recording the +rapid and slight perturbations of the magnet. Comparisons between the +magnetic and atmospheric perturbations gave no result. There was, +however, little stormy weather and no auroral displays. This latter +phenomenon, according to the English missionaries, is rarely observed in +Tierra del Fuego. + +The electrometer used at the Cape was founded upon the principle +developed by Sir William Thomson. The atmospheric electricity is +gathered up by means of a thin thread of water, which flows from a +large brass reservoir furnished with a metallic tube 6.5 feet long. The +reservoir is placed upon glass supports isolated by sulphuric acid, and +is connected to the electrometer by a thread of metal which enters a +glass vessel containing sulphuric acid; into the same vessel enters a +platinum wire coming from the aluminum needle. Only 3,000 observations +were given by the photographic register, due to the fact that the +instruments were not fully protected against constant wet and cold. + +Besides these observations direct observations of the magnetometer were +made, and the absolute determination of the elements of terrestrial +magnetism attempted. + +On the 17th of November, 1882, a severe magnetic disturbance occurred, +lasting from 12 M. until 3 P.M., which in three hours changed the +declination 42'. The same perturbation was felt in Europe, and the +comparison of the observations in the two hemispheres will prove +instructive. + + * * * * * + + + + +THE ELECTRIC RAILWAY AT VIENNA. + + +The total length of this railway, which extended from the Eiskeller in +the Schwimmschul-Allee to the northern entrance of the Rotunda, was +1528.3 meters; the gauge was 1 meter, and 60 per cent. of the length +consisted of tangents, the remaining 40 per cent. being mostly curves +of 250 meters radius. The gradients, three in number, were very small, +averaging about 1:750. + +Two generating dynamos were used, which were coupled in parallel +circuit, but in such a manner that the difference of potential in both +machines remained the same at all times. This was accomplished by the +well known method of coupling introduced by Siemens and Halske, in which +the current of one machine excites the field of the other. + +Although the railroad was not built with a view of obtaining a high +efficiency, an electro-motive force of only 150 volts being used, a +mechanical efficiency of 50 per cent. was nevertheless obtained, both +with one generator and one car with thirty passengers, as well as with +two generators and two cars with sixty passengers; while with two +generators and three cars (two of them having motors) the same result +was shown. + +[Illustration: THE ELECTRIC RAILWAY AT VIENNA.] + +The curves obtained by the apparatus that recorded the current showed +very plainly the action within the machines when the cars were started +or set in motion; at first, the current rose rapidly to a very high +figure, and then declined gradually to a fixed point, which corresponded +to the regular rate of speed. The tractive power, therefore, increases +rapidly to a value far exceeding the frictional resistances, but this +surplus energy serves to increase the velocity, and disappears as soon +as a uniform velocity is reached. + +The average speed, both with one and three cars, was 30 kilometers per +hour.--_Zeitsch. f. Elektrotechnik_. + + * * * * * + + + + +INSTRUCTION IN MECHANICAL ENGINEERING. + +By Professor R. H. THURSTON. + + +The writer has often been asked by correspondents interested in +the matter of technical and trade education to outline a course of +instruction in mechanical engineering, such as would represent his +idea of a tolerably complete system of preparation for entrance into +practice. The synopsis given at the end of this article was prepared +in the spring of 1871, when the writer was on duty at the U.S. Naval +Academy, as Assistant Professor of Natural and Experimental Philosophy, +and, being printed, was submitted to nearly all of the then leading +mechanical engineers of the United States, for criticism, and with a +request that they would suggest such alterations and improvements as +might seem to them best. The result was general approval of the course, +substantially as here written. This outline was soon after proposed as a +basis for the course of instruction adopted at the Stevens Institute of +Technology, at Hoboken, to which institution the writer was at about +that time called. He takes pleasure in accepting a suggestion that its +publication in the SCIENTIFIC AMERICAN would be of some advantage to +many who are interested in the subject. + +The course here sketched, as will be evident on examination, includes +not only the usual preparatory studies pursued in schools of mechanical +engineering, but also advanced courses, such as can only be taught in +special schools, and only there when an unusual amount of time can be +given to the professional branches, or when post graduate courses can be +given supplementary to the general course. The complete course, as here +planned, is not taught in any existing school, so far as the writer is +aware. In his own lecture room the principal subjects, and especially +those of the first part of the work, are presented with tolerable +thoroughness; but many of the less essential portions are necessarily +greatly abridged. As time can be found for the extension of the course, +and as students come forward better prepared for their work, the earlier +part of the subject is more and more completely developed, and the +advanced portions are taken up in greater and greater detail, each year +giving opportunity to advance beyond the limits set during the preceding +year. + +Some parts of this scheme are evidently introductory to advanced courses +of study which are to be taken up by specialists, each one being adapted +to the special instruction of a class of students who, while pursuing +it, do not usually take up the other and parallel courses. Thus, a +course of instruction in Railroad Engineering, a course in Marine +Engineering, or a course of study in the engineering of textile +manufactures, may be arranged to follow the general course, and the +student will enter upon one or another of these advanced courses as his +talents, interests, or personal inclinations may dictate. At the Stevens +Institute of Technology, two such courses--Electrical and Marine +Engineering--are now organized as supplementary of the general course, +and are pursued by all students taking the degree of Mechanical +Engineer. These courses, as there given, however, are not fairly +representative of the idea of the writer, as above expressed, since the +time available in general course is far too limited to permit them to be +developed beyond the elements, or to be made, in the true sense of the +term, advanced professional courses. Such advanced courses as the writer +has proposed must be far more extended, and should occupy the whole +attention of the student for the time. Such courses should be given in +separate departments under the direction of a General Director of the +professional courses, who should be competent to determine the extent of +each, and to prevent the encroachment of the one upon another; but they +should each be under the immediate charge of a specialist capable +of giving instruction in the branch assigned to him, in both the +theoretical and purely scientific, and the practical and constructive +sides of the work. Every such school should be organized in such a +manner that one mind, familiar with the theory and the practice of the +professional branches taught, should be charged with the duty of giving +general direction to the policy of the institution and of directing +the several lines of work confided to specialists in the different +departments. It is only by careful and complete organization in this, as +in every business, that the best work can be done at least expense in +time and capital. + +In this course of instruction in Mechanical Engineering it will be +observed that the writer has incorporated the scheme of a workshop +course. This is done, not at all with the idea that a school of +mechanical engineering is to be regarded as a "trade school," but that +every engineer should have some acquaintance with the tools and the +methods of work upon which the success of his own work is so largely +dependent. If the mechanical engineer can acquire such knowledge in the +more complete course of instruction of the trade school, either before +or after his attendance at the technical school, it will be greatly to +his advantage. The technical school has, however, a distinct field; and +its province is not to be confounded with that of the trade school. +The former is devoted to instruction in the theory and practice of a +profession which calls for service upon the men from the latter--which +makes demand upon a hundred trades--in the prosecution of its designs. +The latter teaches, simply, the practical methods of either of the +trades subsidiary to the several branches of engineering, with only so +much of science as is essential to the intelligent use of the tools and +the successful application of the methods of work of the trade taught. +The distinction between the two departments of education, both of which +are of comparatively modern date, is not always appreciated in the +United States, although always observed in those countries of Europe +in which technical and trade education have been longest pursued as +essential branches of popular instruction. Throughout France and +Germany, every large town has its trade schools, in which the trades +most generally pursued in the place are systematically taught; and every +large city has its technical school, in which the several professions +allied to engineering are studied with special development of those to +which the conditions prevailing at the place give most prominence and +local importance. + +A course of trade instruction, as the writer would organize it, would +consist, first, in the teaching of the apprentice the use of the tools +of his trade, the nature of its materials, and the construction and +operation of the machinery employed in its prosecution. He would next be +taught how to shape the simpler geometrical forms in the materials of +his trade, getting out a straight prism, a cylinder, a pyramid, or a +sphere, of such size and form as may be convenient; getting lines and +planes at right angles, or working to miter; practicing the working of +his "job" to definite size, and to the forms given by drawings, which +drawings should be made by the apprentice himself. When he is able to +do good work of this kind, he should attempt larger work, and the +construction of parts of structures involving exact fitting and special +manipulations. The course, finally, should conclude with exercises in +the construction and erection of complete structures and in the making +of peculiar details, such as are regarded by the average workman +as remarkable "_tours de force_." The trade school usually gives +instruction in the common school branches of education, and especially +in drawing, free-hand and mechanical, carrying them as far as the +successful prosecution of the trade requires. The higher mathematics, +and advanced courses in physics and chemistry, always taught in schools +of engineering, are not taught in the trade school, as a rule; although +introduced into those larger schools of this class in which the aim is +to train managers and proprietors, as well as workmen. This is done in +many European schools. + +As is seen above, the course of instruction in mechanical engineering +includes some trade education. The engineer is dependent upon the +machinist, the founder, the patternmaker, and other workers at the +trades, for the proper construction of the machinery and structures +designed by him. He is himself, in so far as he is an engineer, a +designer of constructions, not a constructor. He often combines, +however, the functions of the engineer, the builder, the manufacturer, +and the dealer, in his own person. No man can carry on, successfully, +any business in which he is not at home in every detail, and in which he +cannot instruct every subordinate, and cannot show every person employed +by him precisely what is wanted, and how the desired result can be best +attained. The engineer must, therefore, learn, as soon and as thoroughly +as possible, enough of the details of every art and trade, subsidiary +to his own department of engineering, to enable him to direct, with +intelligence and confidence, every operation that contributes to the +success of his work. The school of engineering should therefore be so +organized that the young engineer may be taught the elements of every +trade which is likely to find important application in his professional +work. It cannot be expected that time can be given him to make himself +an expert workman, or to acquire the special knowledge of details and +the thousand and one useful devices which are an important part of the +stock in trade of the skilled workman; but he may very quickly learn +enough to facilitate his own work greatly, and to enable him to learn +still more, with rapidity and ease, during his later professional life. +He must also, usually, learn the essential elements and principles of +each of several trades, and must study their relations to his work, and +the limitations of his methods of design and construction which they +always, to a greater or less extent, cause by their own practical or +economical limitations. He will find that his designs, his methods of +construction, and of fitting up and erecting, must always be planned +with an intelligent regard to the exigencies of the shop, as well as to +the aspect of the commercial side of every operation. This extension of +trade education for the engineer into several trades, instead of its +restriction to a single trade, as is the case in the regular trade +school, still further limits the range of his instruction in each. With +unusual talent for manipulation, he may acquire considerable knowledge +of all the subsidiary trades in a wonderfully short space of time, if he +is carefully handled by his instructors, who must evidently be experts, +each in his own trade. Even the average man who goes into such schools, +following his natural bent, may do well in the shop course, under good +arrangements as to time and character of instruction. If a man has not a +natural inclination for the business, and a natural aptitude for it, he +will make a great mistake if he goes into such a school with the hope of +doing creditable work, or of later attaining any desirable position in +the profession. + +The course of instruction, at the Stevens Institute of Technology, +includes instruction in the trades to the extent above indicated. The +original plan, as given below, included such a course of trade education +for the engineer; but it was not at once introduced. The funds +available from an endowment fund crippled by the levying of an enormous +"succession tax" by the United States government and by the cost of +needed apparatus and of unanticipated expenses, in buildings and in +organization, were insufficient to permit the complete organization +of this department. A few tools were gathered together; but skilled +mechanics could not be employed to take up the work of instruction in +the several courses. Little could therefore be done for several years in +this direction. In 1875 the writer organized a "mechanical laboratory," +with the purpose of attaining several very important objects: the +prosecution of scientific research in the various departments of +engineering work; the creation of an organization that should give +students an opportunity to learn the methods of research most usefully +employed in such investigations; the assistance of members of the +profession, and business organizations in the attempt to solve such +questions, involving scientific research, as are continually arising in +the course of business; the employment of students who had done +good work in their college course, when they so desire, in work of +investigation with a view to giving them such knowledge of this peculiar +line of work as should make them capable of directing such operations +elsewhere; and finally, but not least important of all, to secure, by +earning money in commercial work of this kind, the funds needed to carry +on those departments of the course in engineering that had been, up +to that time, less thoroughly organized than seemed desirable. This +"laboratory" was organized in 1875, the funds needed being obtained +by drawing upon loans offered by friends of the movement and by the +"Director." + +It was not until the year 1878, therefore, that it became possible to +attempt the organization of the shop course; and it was then only by the +writer assuming personal responsibility for its expenses that the plan +could be entered upon. As then organized--in the autumn of 1878--a +superintendent of the workshop had general direction of the trade +department of the school. He was instructed to submit to the writer +plans, in detail, for a regular course of shop instruction, and was +given as assistants a skilled mechanic of unusual experience and +ability, whose compensation was paid from the mechanical laboratory +funds, and guaranteed by the writer personally, and another aid whose +services were paid for partly by the Institute and partly as above. The +pay of the superintendent was similarly assured. This scheme had been +barely entered upon when the illness of the writer compelled him to +temporarily give up his work, and the direction of the new organization +fell into other hands, although the department was carried on, as above, +for a year or more after this event occurred. + +The plan did not fall through; the course of instruction was +incorporated into the college course, and its success was finally +assured by the growth of the school and a corresponding growth of its +income, and, especially, by the liberality of President Morton, who met +expenses to the amount of many thousands of dollars by drawing upon his +own bank account. The department was by him completely organized, with +an energetic head, and needed support was given in funds and by a force +of skilled instructors. This school is now in successful operation. +This course now also includes the systematic instruction of students in +experimental work, and the objects sought by the writer in the creation +of a "mechanical laboratory" are thus more fully attained than they +could have possibly been otherwise. It is to be hoped that, at +some future time, when the splendid bequest of Mr. Stevens may be +supplemented by gifts from other equally philanthropic and intelligent +friends of technical education, among the alumni of the school and +others, this germ of a trade school maybe developed into a complete +institution for instruction in the arts and trades of engineering, and +may thus be rendered vastly more useful by meeting the great want, in +this locality, of a real trade school, as well as fill the requirements +of the establishment of which it forms a part, by giving such trade +education as the engineer needs and can get time to acquire. + +The establishment of advanced courses of special instruction in +the principal branches of mechanical engineering may, if properly +"dovetailed" into the organization, be made a means of somewhat +relieving the pressure that must be expected to be felt in the attempt +to carry out such a course as is outlined below. The post-graduate +or other special departments of instruction, in which, for example, +railroad engineering, marine engineering, and the engineering of cotton, +woolen, or silk manufactures, are to be taught, may be so organized that +some of the lectures of the general course may be transferred to them, +and the instructors in the latter course thus relieved, while the +subjects so taught, being treated by specialists, may be developed more +efficiently and more economically. + +Outlines of these advanced courses, as well as of the courses in trade +instruction comprehended in the full scheme of mechanical engineering +courses laid out by the writer a dozen years ago, and as since recast, +might be here given, but their presentation would occupy too much space, +and they are for the present omitted. + +The course of instruction in this branch of engineering, at the Stevens +Institute of Technology, is supplemented by "Inspection Tours," which +are undertaken by the graduating class toward the close of the last +year, under the guidance of their instructors, in which expeditions they +make the round of the leading shops in the country, within a radius of +several hundred miles, often, and thus get an idea of what is meant by +real business, and obtain some notion of the extent of the field of work +into which they are about to enter, as well as of the importance of +that work and the standing of their profession among the others of the +learned professions with which that of engineering has now come to be +classed. + +At the close of the course of instruction, as originally proposed, and +as now carried out, the student prepares a "graduating thesis," in which +he is expected to show good evidence that he has profited well by the +opportunities which have been given him to secure a good professional +education. These theses are papers of, usually, considerable extent, and +are written upon subjects chosen by the student himself, either with or +without consultation with the instructor. The most valuable of +these productions are those which present the results of original +investigations of problems arising in practice or scientific research +in lines bearing upon the work of the engineer. In many cases, the +work thus done has been found to be of very great value, supplying +information greatly needed in certain departments, and which had +previously been entirely wanting, or only partially and unsatisfactorily +given by authorities. Other theses of great value present a systematic +outline of existing knowledge of some subject which had never before +been brought into useful form, or made in any way accessible to the +practitioner. In nearly all cases, the student is led to make the +investigation by the bent of his own mind, or by the desire to do work +that may be of service to him in the practice of his profession. All +theses are expected to be made complete and satisfactory to the head +of department of Engineering before his signature is appended to the +diploma which is finally issued to the graduating student. These +preliminaries being completed, and the examinations having been reported +as in all respects satisfactory, the degree of Mechanical Engineer is +conferred upon the aspirant, and he is thus formally inducted into the +ranks of the profession. + + +COURSE OF INSTRUCTION IN MECHANICAL ENGINEERING. + + +Robert H. Thurston--July, 1871. + +I. + +MATERIALS USED IN ENGINEERING.--Classification, Origin, and Preparation +(where not given in course of Technical Chemistry), Uses, Cost. + +_Strength and Elasticity_.--Theory (with experimental illustrations), +reviewed, and tensile, transverse and torsional resistance determined. + +_Forms_ of greatest strength determined. _Testing_ materials. + +_Applications_.--Foundations, Framing in wood and metal. + +FRICTION.--Discussion from Rational Mechanics, reviewed and extended. + +_Lubricants_ treated with materials above. + +Experimental determination of "coefficients of friction." + +II. + +TOOLS.--Forms for working wood and metals. Principles involved in their +use. + +Principles of pattern making, moulding, smith and machinists' work so +far as they modify design. + +Exercises in Workshops in mechanical manipulation. + +Estimates of _cost_ (stock and labor). + +MACHINERY AND MILL WORK.--Theory of machines. Construction. Kinematics +applied. Stresses, calculated and traced. Work of machines. Selection +of materials for the several parts. Determination of _proportions_ of +details, and of _forms_ as modified by difficulties of construction. + +Regulators, Dynamometers, Pneumatic and Hydraulic machinery. Determining +_moduli_ of machines. + +POWER, transmission by gearing, belting, water, compressed air, etc. + +LOADS, transportation. + +III. + +HISTORY AND PRESENT FORMS OF THE PRIME MOVERS. + +_Windmills_, their theory, construction, and application. + +_Water Wheels_. Theory, construction, application, testing, and +comparison of principal types. + +_Air, Gas, and Electric Engines_, similarly treated. + +STEAM ENGINES.--Classification. [Marine (merchant) Engine assumed as +representative type.] Theory. Construction, including general design, +form and proportion of details. + +_Boilers_ similarly considered. Estimates of _cost_. + +_Comparison_ of principal types of Engines and Boilers. Management and +repairing. Testing and recording performance. + +IV. + +MOTORS APPLIED to Mills. Estimation of required power and of _cost_. + +Railroads. Study of Railroad machinery. + +Ships. Structure of Iron Ships and rudiments of Naval architecture and +Ship propulsion. + +PLANNING Machine shops, Boiler shops, Foundries, and manufactories of +textile fabrics. Estimating _cost_. + +LECTURES BY EXPERTS. + +GENERAL SUMMARY of principal facts, and natural laws, upon the thorough +knowledge of which successful practice is based; and general _resume_ +of principles of business which must be familiar to the practicing +engineer. + +V. + +GRADUATING THESES. + +GRADUATION. + +Accompanying the above are courses of instruction in higher mathematics, +graphics, physics, chemistry, and the modern languages and literatures. + + * * * * * + + + + +IMPROVED DOUBLE BOILER. + + +The operation of boiling substances under pressure with more or less +dilute sulphuric or sulphurous acid forms a necessary stage of several +important manufactures, such as the production of paper from wood, the +extraction of sugar, etc. A serious difficulty attending this process +arises from the destructive action of the acid upon the boiler or +chamber in which the operation is carried on, and as this vessel, which +is generally of large dimensions, is exposed to considerable pressures, +it is necessarily constructed of iron or some other sufficiently +resisting metal. An ingenious method of avoiding this difficulty has +been devised, we believe in Germany, and has been put into practice with +a certain amount of success. It consists in lining the iron boiler with +a covering of lead, caused by fusion to unite firmly to the walls of the +boiler, and thus to protect it from the action of the acid. No trouble, +it is stated, is found to arise from the difference in expansion of the +two metals, which, moreover, adhere fairly well; but, on the other hand, +we believe it does actually occur that the repairs to this lead lining +are numerous, tedious, and costly of execution, so that the system can +scarcely be regarded as meeting the requirements of the manufacturer. +It is to secure all the advantages possessed by a lead-lined vessel, +without the drawback of frequent and expensive repairs, that the +digester, of which we annex illustrations, has been devised by Mr. +George Knowles, of Billiter House, Billiter Street. It consists of a +closed iron cylindrical vessel suitable for boiling under pressure, and +containing a second vessel open at the top, and of such a diameter as to +leave an annular space between it and the walls of the outer shell. This +inner receiver, which may be made of lead, glass, pottery, or any +other suitable material, contains the substance to be treated and the +sulphurous acid or other solution in which it is to be boiled. The +annular space between the two vessels is filled with water to the same +level as the solution in the receiver, and the latter is provided with +suitable pipes or coils, in which steam is caused to circulate for +the purpose of raising the solution of the desired temperature, and +effecting the digesting process. At the same time any steam generated +collects in the upper part of the boiler, and maintains an equal +pressure within the whole apparatus. Figs. 1 to 3 show the arrangement +clearly. Within the boiler, a, is placed the receiver, b, of pottery, +lead, or other material, leaving an annular space between it and the +boiler; this space is filled with water. The receiver, b, is furnished +with a series of pipes, in which steam or hot water circulates, to heat +the charge to the desired temperature. These pipes may be arranged +either in coils, as shown at d, Fig. 1, or vertically at d, Fig. 3. The +latter are provided with inner return pipes, so that any condensed water +accumulating at the bottom may be forced up the inner pipes by the +steam pressure and escape at the top. The vessel is charged through the +manhole, e, and the hopper, c, provided with a perforated cover, and is +discharged at the bottom by the valve, f, shown in Figs. 2 and 3. The +upper part of the boiler serves as a steam dome, and the pressure on the +liquid in the receiver and on the water in the annular space is thereby +maintained uniform. The necessary fittings for showing the pressure +in the vessel, water level indicator, safety valve, cocks for testing +solutions, etc., are of course added to the apparatus, but are not +indicated in the drawing. The arrangement appears to us to possess +considerable merit, and we shall refer to it again on another occasion, +after experiments have been made to test its efficiency.--_Engineering_. + +[Illustration: IMPROVED DOUBLE BOILER.] + + * * * * * + + + + +THE GARDNER MACHINE GUN. + + +[Illustration: FIG. 1.--SINGLE BARREL GARDNER MACHINE GUN.] + +The mechanism by which the various functions of loading, firing, and +extracting are performed is contained in a rectangular gun metal case, +varying in dimensions with the number of barrels in the arm. In the +single barrel gun the size of this case is 14 inches in length, 51/2 +inches in depth, and 21/2 inches in width. The top of the box is hinged, +so that easy access can be had to the mechanism, which consists of a +lock, the cartridge carrier, and the devices for actuating them. In the +multiple barrel guns, the frames which, with the transverse bar at the +end, hold the barrels in place, form the sides of the mechanism chamber, +in the front end of which the barrels are screwed. The mechanism is +actuated by a cam shaft worked by a hand crank on one side of the +chamber. By this means the locks are driven backward and forward, +the latter motion forcing the cartridges into place, and the former +withdrawing the empty cartridge case after firing. The extractor hook +pivoted to the lock plunger rises, as the lock advances, over the rim of +the case, but is rigid as the lock is withdrawn, so that the action is +a positive one. The cartridges, which are contained in a suitable +frame attached to the forward part of the breech chamber, pass through +openings in the top plate of the latter, an efficient distribution being +secured by means of a valve having a transverse motion. Each cartridge +as it falls is brought into the axis of the barrel and the plunger, +while the advance motion of the lock forces them into position. In the +five-barrel gun illustrated by Fig. 3 the cartridge feeder contains 100 +cartridges, in five Vertical rows of 20 cartridges each, and these are +kept supplied, when firing, from supplementary holders. Fig. 1 shows the +portable rest manufactured by the Gardner Gun Company. It consists of +two wrought iron tubes, placed at right angles to each other; the front +bar can be easily unlocked, and placed in line with the trail bar, from +which project two arms, each provided with a screw that serves for the +lateral adjustment of the gun. These screws are so arranged as to allow +for an oscillating motion of the gun through any distance up to 15 deg. +The tripod mounting, used for naval as well as land purposes, is shown +in Fig. 2, which illustrates the two barrel gun complete. The five +barrel gun, Fig. 3, is shown mounted on a similar tripod. The length of +this weapon over all is 53.5 inches, the barrels (Henry system) are 33 +inches long, with seven grooves of a uniform twist of one turn in 22 +inches. + +[Illustration: Fig. 2.--TWO BARREL GARDNER GUN.] + +Gardener's five barrel gun in the course of one of the trials fired +16,754 rounds with only 24 jams, and in rapid firing reached a maximum +of 330 shots in 30 seconds. The two barrel gun fired 6,929 rounds +without any jam; the last 3,000 being in 11 minutes 39 seconds, without +any cleaning or oiling.--_Engineering_. + +[Illustration: Fig. 3.--FIVE BARREL GARDNER GUN.] + + * * * * * + + + + +CLIMBING TRICYCLES. + + +The cycle trade is one which has been developed with great rapidity +within the last ten years, and, like all new industries, has called +forth a considerable amount of ingenuity and skill on the part of those +engaged in it. We cannot help thinking, however, that much of this +ingenuity has been misplaced, and that instead of striving after new +forms involving considerable complication and weight, it would have +been better and more profitable if manufacturers had moderated their +aspirations, and aimed at greater simplicity of design; for it must +be remembered that cyclists are, as a rule, without the slightest +mechanical knowledge, while the machines themselves are subject to very +hard usage and considerable wear and tear in traveling over the +ordinary roads in this country. We refer, of course, more especially to +tricycles, which in one form or another are fast taking the place of +bicycles, and which promise to assume an important position in every +day locomotion. Hitherto one of the chief objections to the use of the +tricycle has been the great difficulty experienced in climbing hills, a +very slight ascent being sufficient to tax the powers of the rider to +such an extent as to induce if not compel him in most instances to +dismount and wheel his machine along by hand until more favorable ground +is reached. To obviate this inconvenience many makers have introduced +some arrangement of gearing speeds of two powers giving the necessary +variation for traveling up hill and on the level. We noticed, however, +one machine at the exhibition which seemed to give all that could be +desired without any gearing or chains at all. This was a direct action +tricycle shown by the National Cycle Company, of Coventry, in which the +pressure from the foot is made to bear directly upon the main axle, and +so transmitted without loss to the driving wheels on each side, the +position of the rider being arranged so that just sufficient load is +allowed to fall on the back wheel as to obtain certainty in steerage. +The weight of this machine is much less than when gearing is used, and +the friction is also considerably reduced, trials with the dynamometer +having shown that on a level, smooth road, a pull of 1 lb. readily +moved it, while with a rider in the seat 4 lb. was sufficient. On this +tricycle any ordinary hill can, it is stated, be ascended with great +ease, and as a proof of its power it was exhibited at the Stanley show +climbing over a piece of wood 8 in. high, without any momentum whatever. +We understand that at the works at Coventry a flight of stairs has been +erected, and that no difficulty is experienced in ascending them on one +of these machines.--_The Engineer_. + + * * * * * + + + + +SUBMARINE EXPLORATIONS. + +VOYAGE OF THE TALISMAN. + + +It was but a few years ago that the idea was prevalent that the seas at +great depths were immense solitudes where life exhibited itself under no +form, and where an eternal night reigned. To-day, thanks to expeditions +undertaken for the purpose of exploring the abysses of the ocean, we +know that life manifests itself abundantly over the bottom, and that +at a depth of five and six thousand meters light is distributed by +innumerable phosphorescent animals. Different nations have endeavored to +rival each other in the effort to effect these important discoveries, +and several scientific missions have been sent to different points of +the globe by the English and American governments. The French likewise +have entered with enthusiasm upon this new line of research, and for +four consecutive years, thanks to the devoted aid of the ministry of the +marine, savants have been enabled to take passage in government vessels +that were especially arranged for making submarine explorations. + +[Illustration: THE FRENCH SCIENTIFIC STEAMER TALISMAN.] + +The first French exploration, which was an experimental trip, was made +in 1880 by the Travailleur in the Gulf of Gascogne. Its unhoped +for results had so great an importance that the following year the +government decided to continue its researches, and the Travailleur was +again put at the disposal of Mr. Alph. Milne Edwards and the commission +over which he presided. Mr. Edwards traversed the Gulf of Gascogne, +visited the coast of Portugal, crossed the Strait of Gibraltar, and +explored a great portion of the Mediterranean. In 1882 the same vessel +undertook a third mission to the Atlantic Ocean, and as far as to the +Canary Islands. The Travailleur, however, being a side-wheel advice-boat +designed for doing service at the port of Rochefort, presented none +of those qualities that are requisite for performing voyages that are +necessarily of long duration. The quantity of coal that could be stored +away in her bunkers was consumed in a week, and, after that, she could +not sail far from the points where it was possible for her to coal up +again. So after her return Mr. Edwards made a request for a ship that +was larger, a good sailer, and that was capable of carrying with it a +sufficient supply of fuel for remaining a long time at sea, and that +was adapted to submarine researches. The Commission indorsed this +application, and the Minister of Instruction received it and transmitted +it to Admiral Jaureguiberry--the Minister of the Marine--who at once +gave orders that the Talisman should be fitted up and put in commission +for the new dredging expedition. This vessel, under command of Captain +Parfait, who the preceding year had occupied the same position on the +Travailleur, left the port of Rochefort on the 1st of June, 1883, having +on board Mr. Milne Edwards and the scientific commission that had been +appointed by the Minister of Public Instruction. The Talisman explored +the coasts of Portugal and Morocco, visited the Canary and Cape Verd +Islands, traversed the Sea of Sargasso, and, after a stay of some time +at the Azores, returned to France, after exploring on its way the Gulf +of Gascogne (Fig.). + +[Illustration: FIG.1.--CHART OF THE TALISMAN'S VOYAGE.] + +The magnificent collections in natural history that were collected +on this cruise, and during those of preceding years made by the +Travailleur, are, in a few days, to be exhibited at the Museum of +Natural History. We think we shall be doing a service to the readers of +this journal, in giving them some details as to the organization of the +Talisman expedition as well as to the manner in which the dredgings were +performed. + +[Illustration: FIG.2.--PLAN OF THE VESSEL.] + +The vessel, as shown by her plan in Fig. 2, had to undergo important +alterations for the cruise that she was to undertake. Her deck was +almost completely freed from artillery, since this would have encumbered +her too much. Immediately behind the bridge, in the center of the +vessel, there were placed two windlasses, one, A, to the right, and the +other, B, to the left (Fig. 2). These machines, whose mode of operation +will be explained further along, were to serve for raising and lowering +the fishing apparatus. A little further back there were constructed +two cabins, G and HH. The first of these was designed to serve as a +laboratory, and the second was arranged as quarters for the members of +the mission. + +The sounding apparatus, the Brothergood engine for actuating it, and the +electric light apparatus were placed upon the bridge. The operating +of the sounding line and of the electric light was therefore entirely +independent of that of the dredges. On the foremast, at a height of +about two meters, there was placed a crane, F, which was capable of +moving according to a horizontal plane. Its apex, as may be seen from +the plan of the boat, was capable of projecting beyond the sides of the +ship, to the left and right. To this apex was fixed a pulley over which +ran the cable that supported the dredges or bag-nets, which latter were +thus carried over the boat's sides. + +[Illustration: FIG.3.--DIAGRAM OF THE THIBAUDIER SOUNDING APPARATUS.] + +The preliminary operation in every submarine exploration consists in +exactly determining the depth of the sea immediately beneath the vessel. +To effect this object different sounding apparatus have been proposed. +As the trials that were made of these had shown that each of them +possessed quite grave defects, Mr. Thibaudier, an engineer of the navy, +installed on board the Talisman last year a new sounding apparatus which +had been constructed according to directions of his and which have given +results that are marvelous. The apparatus automatically registers the +number of meters of wire that is paid out, and as soon as the sounding +lead touches bottom, it at once stops of itself. This apparatus is shown +in Fig. 4, and a diagram of it is given in Fig. 3, so that its operation +may be better understood. The Thibaudier sounding apparatus consists of +a pulley, P (Fig. 3), over which is wound 10,000 meters of steel wire +one millimeter in diameter. From this pulley, the wire runs over a +pulley, B, exactly one meter in circumference; from thence it runs to a +carriage, A, which is movable along wooden shears, runs up over a fixed +pulley, K, and reaches the sounding lead, S, after traversing a guide, +g, where there is a small sheave upon which it can bear, whatever be the +inclination of the boat. The wheel, B, carries upon its axle an endless +screw that sets in motion two toothed wheels that indicate the number +of revolutions that it is making. One of these marks the units and the +other the hundredths (Fig. 5). This last is graduated up to 10,000 +meters. As every revolution of the wheel, B, corresponds to one meter, +the number indicated by the counter represents the depth. Upon the axle +of the winding pulley there is a break pulley, p. The brake, f, is +maneuvered by a lever, L, at whose extremity there is a cord, C, which +is made fast to the carriage, A. When, during the motions due to +rolling, the tension of the steel wire that supports the lead diminishes +or increases, the carriage slightly rises or falls, and, during these +motions, acts more or less upon the brake and consequently regulates the +velocity with which the wire unwinds. When the lead touches bottom, the +wire, being suddenly relieved from all weight (which is sometimes as +much as 70 kilos), instantly stops. + +[Illustration: FIG. 4.--GENERAL VIEW OF THE SOUNDING APPARATUS IN THE +"TALISMAN:"] + +The maneuver of this apparatus may be readily understood. The apparatus +and its weights are arranged in the interior of the vessel. A man bears +upon the lever, L (Fig. 3), and the counter is set at zero. All being +thus arranged, the man lets go of the break, and the unwinding then +proceeds until the lead has touched bottom. During the operation of +sounding, the boat is kept immovable by means of its engine, so that the +wire shall remain as vertical as possible. The bottom being reached, the +unwinding suddenly ceases, and there is nothing further to do but read +the indication given by the differential counter, this giving the depth. + +[Illustration: FIG. 5.--APPARATUS FOR MEASURING THE LENGTH OF THE WIRE +PAID OUT.] + +Near the winding pulley, there is a small auxiliary engine, M, which +is then geared with the axle of the said pulley, and which raises the +sounding apparatus that has been freed from its weight by a method that +will be described further along. + +We have endeavored in Fig. 4 to show the aspect of the bridge at the +moment when a sounding was about being made. From this engraving (made +from a photograph) our readers may obtain a clear idea of the Thibaudier +sounding apparatus, and understand how the wheel over which the wire +runs is set in motion by the Brothergood engine.--_La Nature_. + + * * * * * + + + + +CABLE GRAPNEL. + + +Some improvements have recently been made by Mr. Alexander Glegg and the +inventor in the well-known Jamieson grapnel used for raising submerged +submarine cables. The chief feature of the grapnel is that the flukes, +being jointed at the socket, bend back against a spring when they catch +a rock, until the grapnel clears the obstruction, but allow the cable +to run home to the crutch between the fluke and base, as shown in the +figures. In the older form the cable was liable to get jammed, and cut +between the fixed toe or fluke and the longer fluke jointed into it. +This is now avoided by embracing the short fluke within the longer one. +The shank, formerly screwed into the boss, is now pushed through and +kept up against the collar of the boss, by the volute spring, which at +the same time presses back the hinged flukes after being displaced by +a rock. The shank can now freely swivel round, whereas before it was +rigidly fixed. The toes or flukes are now made of soft cast steel, which +can be straightened if bent, and the boss is made of cast steel or +gun-metal. + +[Illustration: JAMIESON'S GRAPNEL.] + + * * * * * + + + + +WRETCHED BOILERMAKING. + + +_To the Editor of the Scientific American_: + +As long as I have been a reader of the SCIENTIFIC AMERICAN I have been +pleased with the manner in which you investigate and explain the cause +of any boiler explosion which comes to your knowledge; and I have +rejoiced when you heaped merited censure upon the fraudulent +boilermaker. In your paper in December last you copied a short article +on "Conscience in Boilermaking," in which the writer, after speaking +of the tricks of the boilermaker in using thinner iron for the center +sheets than for the others, and in "upsetting" the edges of the plates +to make them appear thicker, goes on to say: "We call attention to this, +because the discovery of such practice has made serious trouble between +the boilermaker and the steam user. We would not believe that there were +men so blind to the duties and obligations which rest upon them as +to resort to such practice, but the careful inspector finds all such +defects, and in time we come to know whose work is carefully and +honestly done, and whose is open to suspicion. In States and cities +where inspection laws are in force that give the methods and rules by +which the safe working pressure of a boiler is calculated, there is no +alternative except to follow the rules; and if certain requirements +regarding construction are a part of the law, there is no authority or +right to depart from it, and yet there are boilermakers who try to force +their boilers into such localities when their work is not up to the +requirements of the law." + +Now, if some boilermakers are so dishonest as to try and impose upon the +locomotive engineer, who they know will carefully examine every part of +his boiler, and who is able to detect any flaw, it is not to be expected +that the farmer will escape. Nor does he. The great number of explosions +of boilers used in thrashing and in other farm work proves that there +are boilermakers who "force their boilers into such localities +when their work is not up to the requirements of the law." And the +boilermaker, if he be dishonest, is doubly tempted if the broad width of +a continent intervenes between him and the farmer for whom his work is +intended, and if in the place where the boiler is to be used there are +no inspection laws in force. The farmer who lives many miles from a +city, and who has no means of testing any boiler he may purchase, +is wholly at the mercy of the boilermaker, and must run it until it +explodes or time proves it to have been honestly made. Then, again, +there are boilermakers who, although making boilers of good iron and of +the proper thickness, finish them off so badly that the farmer is put to +great inconvenience and expense to put them in working order. Two years +ago I purchased a straw-burning engine and boiler made by an Eastern +firm. Before it had run ten days the boiler began to leak at the +saddle-bolt holes. The engineer tightened the nuts as far as possible, +but could not stop the leaks, which at last became so bad that we had to +stop work and take the engine to the shop. Upon taking off the saddle +and taking out the bolts it was discovered that they were too small for +the holes in the boiler, and that they had been wrapped with candle wick +and white lead to make them fill the holes, and that a light washer had +been put on each bolt between the head and the inside of the boiler. +This washer kept the lead in its place, and prevented the boiler from +showing a leak when first fired up. The water pipes in the fire-box soon +gave out and became utterly useless. Upon inquiring of the patentee of +this straw-burning device, who was supposed to have put it in my boiler, +he stated that he had had nothing to do with it, but that it was put in +by the firm selling these engines, and "as cheaply as possible." Before +I got this boiler and engine in fair running order I had spent hundreds +of dollars and had to do entirely away with the water grates. + +Last summer, needing another tharshing engine, I was induced to buy +one of the same make as my old one, but with a different straw-burning +device. The firm who sold it to me agreed that it should have none of +the faults of the old one. Well, I got it, and, upon hauling it out to +my ranch, and getting up steam, I found it to be much worse than the +first one I had bought. The boiler leaked at nearly every hole where +a tap had been screwed into it. It took an engineer, a boilermaker, a +blacksmith, and a fireman several days to get it in shape so that we +could use it at all; and after we did start up, the boilermaker had +to be sent for several times to stop new leaks that were continually +showing themselves. + +I send you by this mail for your inspection one of the saddle bolts and +one of the bolts taken out of the piston, and also the certificates of +the engineer, boilermaker, and machinist who repaired the boiler. In +justice to my fellow-farmers I ought to publish these certificates and +the names of these boilermakers to the world, but, for the present at +least, I refrain from so doing. These boilermakers will see this article +and they will know, if the public does not, for whom it is intended. If +it has the effect of making them exercise more care in the construction +and fitting up of their engines and boilers, I have not written in vain. + +D. FREEMAN. + +Los Angeles, Cal., March 7,1884. + +[The two bolts and the certificates above referred to accompany the +letter of Mr. Freeman. We can only wonder how it was that, after having +been treated as he relates in the first instance, he should have had any +further business with parties who would send out such boilers, for the +testimony of the engineer and workmen make the case even stronger than +Mr. Freeman has put it.--ED.] + + * * * * * + + + + +A THREADED SET COLLAR. + + +There are cases where a long screw must be rotated with a traversing nut +or other threaded piece traveling on its thread a limited and variable +distance. At one time the threaded nut or piece may be required to +go almost the entire length of the screw, and at another time a much +shorter traverse would be required. In many instances the use of side +check nuts is inconvenient, and in some it is impossible. One way of +utilizing the nut as a set collar is to drill through its side for a set +screw, place it on its screw, pour a little melted Babbitt metal, or +drop a short, cold plug of it into the hole, tap the hole, and the tap +will force the Babbitt into the threads. + +Insert the set screw, and when it acts on the Babbitt metal it will +force it with great friction on to the thread without injuring the +thread; and when the set screw tension is released, the nut turns +freely. A similar and perhaps a better result may be obtained by +slotting the hole through the nut as though for the reception of a key. +Secure a key (preferably of the same material as the nut) by slight +upsetting at its ends, and then thread the nut, key, and all. Place +a set screw through the nut over the threaded key, and the job is +complete. + + * * * * * + + + + +PNEUMATIC MALTING. + + +The lethargy in the malting trade, and in all matters relating to +malting processes, induced by two centuries of restrictive legislation, +is being gradually shaken off by the malting industry under the new law. +For many years nearly all improvements in malting processes originated +abroad, as numberless Acts of Parliament fettered every process and the +use of every implement requisite in a malt-house in this country. The +entire removal of these legislative restrictions gives an opportunity +for improved processes, which promises to open up a considerable +field for engineering work, and to develop a very backward art by the +application of scientific principles. The present time is, therefore, +one of more material change than malting has ever experienced. + +[Illustration: PNEUMATIC MALTING AT TROYES. Fig. 1.] + +Of the numerous improvements effected in the past few years, those made +by M. Galland in France, and more recently by M. Saladin, are by far the +most prominent. M. Galland originated what is known as the pneumatic +system eight or nine years ago. This system is carried out at the +Maxeville brewery, near Nancy. + +[Illustration: PNEUMATIC MALTING AT TROYES. Fig. 2.] + +Since that time further improvements have been made by M. Galland; but +more recently great advances have been made in the system by M. +Saladin. He has developed the practice of the leading principle, and in +conjunction with Mr. H. Stopes, of London, has added improved kilns and +various mechanical apparatus for performing the work previously done by +hand. He has also devised a very ingenious machine for cooling the moist +air by which the process is carried on. + +[Illustration: FIG. 4.--ECHANGEUR AND TURNING MACHINE.] + +At the recent Brewery Exhibition, some of the machinery used in these +new maltings was shown in action by Messrs. H. Stopes & Co., together +with drawings of a malting constructed at Troyes for M. Bonnette under +M. Saladin's instructions. This malting is the third constructed for the +same firm, the others being at Nancy. That at Troyes we now illustrate. +We will not occupy space by a general description of the pneumatic +system, one great feature in which is the continuous manufacture of malt +throughout the year instead of only from five to eight months of the +year, as it will be gathered from the following description of the +Troyes malting: + +[Illustration: FIG. 5.--ECHANGEUR, AXIAL SECTION.] + +In our engravings, Figs. 1, 2, and 3, the letter A indicates the +germinating cases; B, Saladin's patent turning screws; C A, air +channels; D, passages; E R, main driving shafts; e, pulleys; F, metal +recesses to fit turning screws; G, elevators; H, trap doors; I, air +channels; J, openings to growing floor for air; K S, engines and fan +room; L N, fans, supply and exhaust; T, boiler; U, chimney; f, well. The +capacity of the malting is 130 qr. malt every day. This is equivalent to +an English house of 520 qr. steep. The whole space occupied is the area +necessary for kilns, malt and barley stores, engine and boiler house, +and fans. No additional area is required for germinating floors, as ten +germinating cases, A, are placed in the basement below the kilns and +stores. The building is of brick, with the internal walls below the +ground line resting upon cast iron columns and rolled joists. The +germinating cases, A A, are of iron; the bottoms are double. One of +perforated plate is placed 6 inches above the bottom. These plates admit +of draining the corn if the germinating case is used as a steeping +cistern also. Their chief object is, however to admit of ready +circulation of the air by the means presently to be described. Large +channels, A a, serve as drains for moisture and to convey the air to or +from the growing corn. Between each case is a passage, D, enabling the +maltster to have free access to the corn at all points. + +[Illustration: FIG. 6.--ECHANGEUR TRANSVERSE SECTION.] + +With the exception of the driving shaft, E, all the machinery is in +duplicate, so that the possibility is remote of any breakdown that would +seriously affect the working of the house. This is necessary, as should +the fans, L N, be stopped for twenty-four hours the corn germinating +at a depth exceeding 30 inches would heat and impair its vitality. The +boilers, T, and engines, S, are of the common type of 20 horse power +nominal. The fans, L N, are the Farcot patent, illustrated a short time +since in our pages. The lower floors of the kilns are provided with +the Schlemmer patent mechanical turners. The turners, Fig. 4, in the +germinating cases are Saladin's patent. + +[Illustration: FIG. 7.--ECHANGEUR, SECTIONAL PLAN.] + +The germination of the grain is effected by means of cool moist air +provided by the fan described and the cooler and moistener--Figs. 5, 6, +and 7, herewith--known as an _echangeur_. As the germinating grain has +a depth of from 30 inches to 40 inches some pressure is required, and +mechanical means are necessary for efficient and economical turning. +The _echangeur_ is a very ingenious application of the well understood +rapidity of evaporation of any liquid when spread out in very thin +layers over large surfaces and exposed to a current of air. It consists +of a cylinder, or series of cylinders, of increasing diameter, placed +one within another. Each consists of finely perforated sheet iron. They +are placed in a trough of water, just sufficiently immersed to insure +complete wetting. When rotated at a slow speed, the surfaces of all the +cylinders are kept just wetted. A volume of air is either driven or +drawn through, as may be required for any particular purpose. In the +model malting, as shown at Fig. 4, taken from that shown at the Brewery +Exhibition, the air was driven through the _echangeur_ and thence +through the germinating barley. Here or as employed in the malting +illustrated, the air in its passage comes first into contact with the +moistened cylinders, and if hot and dry it becomes moist and cool, for +the constant evaporation upon the cylinders has a very considerable +refrigerating effect. + +This was well known to the Egyptians over four thousand years ago, and +the porous bottle--_gergeleh_--of Esnch has been made until the present +day, to keep the drinking water cool and fresh. The _echangeur_ is +like a gigantic gergeleh, and by increasing the size and number of the +cylinders, and causing the water in the moistening trough to circulate, +any volume of air can be wetted to the saturation limit corresponding to +its temperature. It will be seen that this apparatus gives the maltster +complete control of the humidity and heat as well as volume of the air +driven through germinating corn. + +[Illustration: Fig. 8.] + +The turning apparatus is shown by Fig. 4, and consists, as will be seen, +of a cylindrical frame provided with rollers which run on rails at the +edge of the germinating cases. It is carried to and fro from either end +of the case by compensating rope gearing which at the same time gives +motion to the gearing actuating the turning screws. These screws do not +quite touch the bottom of the germinating case, but are provided with a +pair of small brushes, as shown in the annexed engraving, Fig. 8, which +just skim it. The apparatus shown has but three of these screws, but the +cases are generally made wide enough for six. The kilns are double, +each possessing two floors, and worked upon the Stopes' system. The +construction of the furnaces is of the ordinary French pattern. The +arrangement of the house permits of great regularity in working. Every +day 130 qrs. of barley is screened, sorted, cleaned, and passed into a +steeping cistern. When sufficiently steeped it runs through piping into +the germinating case, which, in the natural order of working, is empty. +Here it forms the couch. When it is desirable to open couch a small +amount of air is forced through the grain by opening the trap door +connected with the main air channel. This furnishes the growing corn +with oxygen, removes the carbonic acid gas, and regulates temperatures +of the mass of grain. Later the Saladin turner is put in motion about +every eight to twelve hours. The screws in rotating upon their axes are +slowly propelled horizontally. They thus effectually turn the grain and +leave it perfectly smooth. This turning prevents matting of the roots, +the regulation of temperature and exposure to air being effected +by means of the cold air from the _echangeur_. When the grain is +sufficiently grown it is elevated to the kilns. For forty hours it +remains upon the top floor. It is then dropped upon the bottom floor, a +further charge of green corn following upon the top floor. The benefit +is mutual. The bottom floor is maintained at an even temperature, being +virtually plunged in an air bath; free radiation of heat is prevented; +the top surface of the malt is necessarily nearly as warm as that next +the wires, which in its turn is subject to lower heats than would be +necessary if free radiation from the surface was allowed. The top floor +is by the intervention of the layer of malt between it and the fire +prevented it from coming into direct contact with heat of a dangerous +and damaging degree. The same heat which is used to dry one floor, and +in an ordinary kiln passes at once into the air as waste, is the best +possible description of heat, namely, very slightly moistened heated +air, to remove the moisture from the second layer of malt at a low +temperature. It is of vital importance to retain this green malt at a +low heat so long as any percentage of moisture exceeding, say, 15 per +cent, is retained by the corn. + +The regulation of temperature is shown by the diagrams, Figs. 9 and 10: + +[Illustration: Fig. 9.] + +[Illustration: Fig. 10.] + +The distribution of the heated air in the kiln is rarely as uniform as +is supposed, the temperature of the malt on drying floor being very +different at different parts. In illustration of this, the following may +be taken from a statement by Mr. Stopes of the results of an examination +of the temperatures at different parts of a drying floor in a kiln in +Norfolk: "A malting steeping 105 qr. every four days has a kiln 75 +feet by 36 feet; an average drying area of under 26 feet per qr. The +consequent depth of green malt when loaded is over 10 inches. The total +area of air inlets is less than 27 feet super. The air outlet exceeds +117 feet, a ratio of 13 to 3. The capacity of head room equals 44,550 +feet cube. The area of each tile is 144 inches, with 546 holes, giving +an effective air area of some 32 inches. The ratio of non-effective +metallic surface to air space is thus 9 to 2." The Casella anemometer +gave no indications at several points, and fluctuating up and down +draughts were observable at many others, especially at two corners and +along the center. "The strongest upward draught pulsated with the gusts +of wind and ranged from 30 feet to 54 feet per minute, a down draught of +equal intensity occurring at intervals at the same spot, notwithstanding +the fact that the air was rushing in at the inlets below the floor at +the high velocity of 785 feet per minute. The temperatures of the drying +malt and superimposed air consequent upon the conditions thus indicated +were naturally as follows: At B, the place supposed to be hottest: Heat +of malt touching tiles, 216 deg.; heat of malt 1 inch above tiles, 167 +deg.; heat of malt 3 inches above tiles 154 deg.; heat of malt 4 inches +above tiles, 152 deg.; heat of malt 5 inches above tiles, 142 deg.; heat +of malt on surface, 112 deg. At A, the place supposed to be coldest: +Heat of malt next tiles, 174 deg.; heat of malt 2 inches above tiles, +143 deg.; heat of malt 4 inches above tiles, 135 deg.; heat of malt on +surface, 104 deg.; the heat of the air 3 feet above tiles, 84 deg.; the +heat of the air 5 feet above tiles, 82 deg. Fig. 9 shows the temperature +at twenty-six points close to the tiles, taken with twelve registered +and accurate thermometers in the space of fifteen minutes." These and +other similar tests have led to the conclusion that the best malt drying +cannot be done on a single floor. + +Fig. 10 is a similar diagram showing the temperatures on a drying floor +of kiln at Poole, Dorset, altered to Stopes' system of drying. The +temperature at different depths of the drying grain was as follows: Malt +at surface of tiles, 142 deg.; malt at 1 inch above tiles, 142 deg.; +malt at 2 inches above tiles, 142 deg.; malt at 4 inches above tiles, +141 deg.; malt on surface, 140 deg. + +The advantages of the Saladin system over that hitherto working in +Britain are numerous, and are thus enumerated by Messrs. Stopes & Co. +who are agents for M. Saladin: The area occupied by the building does +not equal one-third of that otherwise required. The actual growing-floor +space is only about one-seventh, and the number of workmen is ruled +necessarily by the size of the house, but on an average is reduced +two-thirds; but the employment of much more power is necessary, and the +power is used at more frequent intervals. The use of plant and premises +is continuous, the processes of malting being equally well performed +during the summer months. The further advantage of this is that brewers +secure entire uniformity in age of malt. By the English system the +stocks of finished malt necessarily fluctuate largely. All grain is +subjected to the same conditions of surrounding air, exposure, and +temperature. The volume of air supplied to the germinating corn is +entirely under control, as are also its temperature and humidity. When +germination is arrested and the green malt is drying, the double kilns +insure control of the temperatures of the corn in the kilns. The +infrequency of turning the germinating grain benefits the growth of the +roots and the development of the plumule, besides saving much labor. No +grains are crushed or damaged by the feet or shovels of workmen. The air +supplied to the corn can be inexpensively freed from disease germs +and impurities. The capital needed for malting can be reduced by the +diminished cost of installation, and the reduced stocks of malt on hand. +The quality of the malt made is considerably improved. The percentages +of acidity are much reduced. The stability of the beer is increased, +and a greater percentage of the extractive matter of the barley is +obtainable by the brewer.--_The Engineer_. + + * * * * * + + + + +NON-SPARKING KEY. + + +Profs. Ayrton and Perry lately described and exhibited before the +Physical Society their new ammeters and voltmeters, also a non-sparking +key. The well known ammeters and voltmeters of the authors used for +electric light work are now constructed so as to dispense with +a constant, and give the readings in amperes and volts without +calculation. This is effected by constructing the instruments so +that there is a falling off in the controlling magnetic field, and a +considerable increase in the deflecting magnetic field. The deflections +are thus made proportional to the current or E.M.F. measured. The +ingenious device of a core or soft iron pole-piece, adjustable between +the poles of the horseshoe magnet, is used for this purpose. By means of +an ammeter and voltmeter used conjointly, the resistance of part of the +circuit, say a lamp or heated wire, can be got by Ohm's law. Profs. +Ayrton and Perry's non-sparking key is designed to prevent sparking with +large currents. It acts by introducing a series of resistance coils +determined experimentally one after the other in circuit, thereby +cutting off the spark. + + * * * * * + + + + +NEW INSTRUMENTS FOR MEASURING ELECTRIC CURRENTS AND ELECTRO-MOTIVE +FORCE. + +By Messrs. R. E. CROMPTON and GISBERT KAPP. + +[Footnote: Paper read before the Society of Telegraph Engineers, 14th +February, 1884.] + + +In consequence of the rapid development of that part of electrical +science which may be termed "heavy electrical engineering," reliable +measuring instruments specially suitable for the large currents +employed in lighting and transmission of energy have become an absolute +necessity. As usual, demand has stimulated supply, and many ingenious +and useful instruments have been invented, the manufacture of which +forms at the present day an important industry. Mr. Shoolbred, in a +paper which he recently read before this Society, gave a full and +interesting account of the labors of our predecessors in this field. +To-day we add to the list then given a class of instruments invented by +us, examples of which are now before you on the table. We have preferred +to call them current and potential indicators in preference to meters, +considering that the latter term, or rather termination, ought to be +applied rather to integrating instruments, which the necessities of +electric lighting, we believe, will soon bring into extensive use. The +principal aim in the design of these indicators has been to obtain +instruments which will not alter their calibration in consequence of +external disturbing forces. If this object can be attained, then it will +be possible to divide the scale of each instrument directly into amperes +or volts, as the cause may be, and thus avoid the use of a coefficient +of calibration by which the deflection has to be multiplied. This is an +important consideration when it is remembered that in many cases +these instruments have to be used by unskilled workmen, to whom a +multiplication involving the use of demical fractions is a tedious and +in some cases even an impossible task. + +[Illustration: FIG. 1. FIG. 2.] + +All measurements are comparative. We measure weights or forces by +comparison with some generally known and accepted unit standard +weights, lengths, areas, and volumes, by comparison with a unit length, +resistance by a standard ohm, and so forth. In the same way currents +could be measured by comparison with a standard current: but this +would be a troublesome process, not only on account of the apparatus +necessary, but also because it would be a matter of some difficulty to +have a standard current always ready for use. In general, measurement +by direct comparison with a standard unit is discarded for the more +indirect method of measuring not the current itself, but its chemical, +mechanical, or magnetic effect. The chemical method is very accurate if +a proper density of current through the surface of the electrodes be +used,[1] but since it requires a considerable time, and, above all, an +absolutely constant current, its use is almost entirely restricted +to laboratory work and to the calibration of other instruments. For +practical ready use, instruments employing the mechanical or magnetic +effect of the current are alone suitable. We weigh, so to speak, the +current against the force of a magnet, of a spring, or of gravity. +The measurement will be exact if the thing against which we weigh or +counterbalance the current itself retains its original standard value. +Where permanent magnets or springs are used as a balancing force, this +condition of constancy in our weights and measures is not always fully +maintained, and to make matters worse, there is no visible sign by which +a change, should it have occurred, can be readily detected. A spring +may have been overstrained or a steel magnet may have become weakened +without showing the least alteration in outward appearance. To overcome +this difficulty, the obvious remedy is not to use springs or steel +magnets at all, but to substitute for these some other force which +should be either absolutely constant, such as the force of gravity, or +at least should, vary only within narrow limits, and this in accordance +with a definite law. This latter condition can be fulfilled by the +employment of electro-magnets. + +[Footnote 1: According to recent experiments made by Dr. Hammerl, the +density of current in a copper voltameter should be half an ampere per +square inch of surface.] + +[Illustration: FIG 3.] + +To imitate with an electro magnet as nearly as possible a permanent +magnet, so that the former can be used to replace the latter, it is +necessary that the magnetism in the iron core should remain constant. +This could, of course, be done by exciting the electro magnet with a +constant current from a separate source. (In a recent note to the Paris +Academy of Science, M.E. Ducretet described a galvanometer with steel +magnet, which is surrounded by an exciting coil. When recalibration +appears necessary, a known standard current from large Daniell cells is +sent through this coil during a certain time, and thus the magnet is +brought back to its original degree of saturation. M. Ducretet also +mentions the use of a soft iron bar instead of a steel magnet, in which +case the current from the Daniell cells must be kept on during the time +an observation is taken.) But such a system would appear to be too +complicated for ready use. Moreover, some sort of indicator would be +required by which we could make sure that the exciting current has the +normal strength. + +[Illustration: FIG 4.] + +The plan we adopt is to excite the electro magnet by the whole or a part +of the current which is to be measured. Since this current varies, the +power exciting the core of the electro magnet must also vary; and since +we require the core to have as nearly as possible a permanent magnetic +force, we are brought face to face with the question, whether an electro +magnet can be constructed that has a constant moment under varying +exciting currents. This question has been answered by the well known +experiments of Jacobi, Dub, Mueller, Weber, and others. To get an +absolutely constant magnetic moment, is not possible, but between +certain limits we can get a very near approximation to constancy. + +[Illustration] + +The relation between exciting power and magnetic moment is very +complicated, depending not only on the dimensions and shape of the core +and the manner of winding, but also on the chemical constitution of the +iron of the core. It is not possible, or at least it has hitherto not +been found possible, to embody all these various elements into an exact +mathematical formula, which would give the magnetic moment as a function +of the exciting current; but the above mentioned experiments have shown +that within certain limits, and in the neighborhood of the point of +saturation, the relation between the two is that of an arc to its +geometrical tangent. It will be seen that for large angles the arc +increases much slower than the tangent; that is, for strongly excited +cores, a very large increase of the exciting current will produce only +a slight increase of magnetic moment. If Mueller's formula were correct +for all currents, absolute saturation could only be reached with an +infinite current. Whether this be the case or not, it is certain that +the greater the exciting current the less will a variation in it affect +the magnetic moment of the core. To imitate as nearly as possible +permanent steel magnets, it is therefore necessary to use electro +magnets, the cores of which are easily saturated. The core should be +thin and long and of the horseshoe type; the amount of wire wound round +it should be large in comparison with the size of the core. + +[Illustration] + +Here is a magnet partly wound which was used in one of our earliest +experiments, but which was a failure on account of having far too much +mass in the core in comparison with the amount of copper wire wound +round it. Since then we have greatly diminished the iron and increased +the copper. The cores of the instruments on the table are composed of +two or three No. 18 b.w.g. charcoal iron wires, and are wound with one +layer of 0'120 inch wire in the case of the current indicators, and +eighteen layers of 0.0139 inch wire in the case of the potential +indicator. If from the diagram, Fig. 1, we plot a curve the abscissae of +which represent exciting current, and the ordinates magnetic moment of +the soft iron core, we find that a considerable portion of the curve +is almost a straight and only slightly inclined line. If it, were a +horizontal straight line the core would be absolutely saturated, but +such as it is, it answers the purpose sufficiently well, for with a +variation of exciting current from 10 to 100 amperes the magnetic moment +varies but slightly. If a small soft iron or magnetic steel needle, _n +s_, be suspended between the poles, S N, of an electro magnet of such +proportions as described above, and the current, after exciting the +electro magnet, _e e_, be lead round the coils, DD, it will be found +that for all currents between 10 and 100 amperes the needle, _n +s_, shows a definite deflection for each current. Here we have a +galvanometer with permanent calibration. In this case the deflection of +the needle will not strictly follow the law of tangents, because the +directing power of the electro magnet is not absolutely constant; but +whatever the exact ratio between deflection and current may be, it must +always remain the same, and to each angle of deflection corresponds one +definite strength of current. + +[Illustration] + +The force with which the electro magnet tends to keep the needle in its +zero position, that is, in line with the poles, S N, is due partly to +the magnetism of the core, which is nearly constant, and partly to the +magnetic influence of the coils, _ee_, themselves, which is, of course, +simply proportional to the current. The total magnetic force acting on +the needle is, therefore, represented by the sum of these two forces, +and consequently not nearly so constant as might be desired in order to +get a good imitation of a tangent galvanometer with a permanent magnet. +In the diagram, Fig. 2, the curve, O A B, represents the magnetic moment +of the iron core, the straight line, ODE, that of the exciting coils per +se, and the dotted line, O F M, the sum of the two, obtained by adding +for every current, O C, the respective ordinates, CD and C A. + + CF = CD + CA + +The rise of this curve shows that the force which tends to bring the +needle back to its zero position increases with the current, though at a +slower ratio than the deflecting force of the current. It follows from +this that for large currents the increment in the angle of deflection is +comparatively small, and the divisions on the scale whereon the current +is to be read off would come too near together to allow accurate +readings to be taken. In other words, the range of accurate reading in +an instrument so constructed would only be limited. But it is very easy +to eliminate the magnetic effect of the coils of the electro magnet on +the needle, by introducing an opposite magnetic effect, so that only +that part of the force remains which belongs to the soft iron core +proper. One way of doing this is by surrounding the needle with a coil, +the plane of which is at right angles to the line, S N, and coupling +this coil in series with the deflecting coil, D D. If the proportions +of this transverse coil and the direction of the current through it +be properly chosen, its magnetic effect can be made to exactly +counterbalance that of the exciting coils, _e e_, without perceptibly +weakening the magnetism of the iron core. But instead of employing two +coils, one parallel and the other transversely to the zero position of +the needle, we can obtain the same result in a more simple manner with +one coil only, if this be placed at such an angle that its magnetic +effect can be substituted for the combined effects of the two coils. In +other words, we set the deflecting coil, D D, at a certain angle to the +zero position of the needle. + +A similar arrangement, though not precisely for the same purpose, has +already been suggested and tried by Messrs. Deprez, Carpentier, Ayrton, +and Perry, in galvanometers with permanent steel magnets. If the coil, +D D, be so placed, the deflecting force which now acts obliquely can be +considered as the resultant of two forces, one acting at right angles to +the line, S N, as in an ordinary galvanometer, and the other parallel to +this line, but in a sense opposed to the action of the electro magnet +and its exciting coils. If the angle of obliquity be so chosen that this +latter component exactly equals the magnetic effect of the exciting +coils _per se_, an equality which holds good for all currents, then we +shall have an almost perfect imitation of a tangent galvanometer with +permanent magnets. But we can go a step further than this; we can +overbalance the exciting coils by setting the deflecting coil at a +greater angle than necessary for the mere elimination of the former, and +thus attain that an increase of current results in a slight weakening of +the field in which the needle swings, thus allowing the increment of the +angle of deflection to be comparatively large even for large currents. +In this way it is possible to obtain a more evenly divided scale than +in the case when the deflection follows the law of tangents, as in an +ordinary tangent galvanometer. This principle of overbalancing the +exciting coils is shown on diagram, Fig. 2. The straight line, O G, +represents the magnetic effect on the needle of that component of the +deflecting force which is parallel, but in sense opposed to S N; +as mentioned above, the magnetic effect of the exciting coils is +represented by the straight line, O E. The combined effect of these two +forces on the needle is represented by the line, O K, the ordinates +of which must be deducted from those of the curve, O A B, in order to +obtain the total directing force due to each current. This is shown by +the curve, O P Q, shown in a thick full line. This curve shows how +the directing force or strength of field in which the needle swings +decreases with an increasing current. That this does actually take place +can easily be proved by experiment. + +Fig. 4 shows two curves; the one drawn in a full line is obtained +by plotting the deflection in degrees of the needle of a potential +indicator as abscissae, and the corresponding electromotive forces +measured simultaneously on a standard instrument as ordinates; the +dotted line shows what this curve would be with an ordinary tangent +galvanometer. + +The needle of the potential indicator is mounted at the lower end of +a steel axle, to the upper end of which is fastened a light aluminum +pointer, whereby the deflection of the needle can be read off on a scale +divided directly into volts. The scale is placed within a circular dial +plate with glass cover, giving sufficient room for the pointer to swing +all round, and the needle is placed within a central tube fitting it +closely, which acts as a damper and so makes the instrument almost +dead beat. Tube and dial are in one casting. The electro magnet is of +horseshoe form fastened to a central tubular stand, which also serves +to support the two deflecting coils, one on either side of it. The tube +within which the magnetic needle swings is inserted into the stand, +which is bored out to the external diameter of the tube. The electro +magnet and deflecting coils are wound with from 50 to 100 ohms of fine +insulated copper wire, and an additional resistance coil of from 450 +to 900 ohms of German silver is added, which can, however, be short +circuited by depressing a key when the instrument has to be used for +reading low electromotive forces. In this case the indication of the +pointer must be divided by ten. If a current be sent through the +instrument the wrong way, the needle turns through an angle of 180 deg., and +thus brings the pointer to the side of the dial opposite to where the +scale is. In this position no reading can be taken, and to facilitate +the sending of the current in the right direction a commutator is added, +and the same is so coupled up that when the pointer stands over the +scale the handle on the commutator points to the positive terminal +screw. There is a limit of electromotive force below which the indicator +fails to give reliable readings. For instance, an instrument wound with +100 ohms of copper wire and 900 ohms of German silver can be used for +electromotive forces varying between 300 and 3 volts, but would not be +reliable for measuring less than 3 volts. + +For very exact measurements the instrument should be placed north and +south, in the same position in which it was calibrated. Two different +patterns of current indicators are on the table; one with double needles +suspended on a point in the way compass magnets are suspended, the other +with one lozenge shaped needle mounted on an axle and pivoted on jewels, +in every way similar to the needle of the potential indicator first +described. + +For measurements of currents from 10 amperes upward, there is no need +to employ a complete coil as the deflecting agent; one half-coil or one +strip passing close under the needle gives sufficient deflecting force, +and thus the construction of the instrument is rendered extremely +simple. The current, after entering at one of the flat electrodes, +splits in two parts, each part passing round the winding of an electro +magnet of horseshoe form, the similar poles of both magnets pointing +toward each other and toward the needle. After traversing the winding, +the current unites again, and passes through a metal strip close under +the needle, and finally out of the instrument by the other electrode, +which lies close under that at which the current entered, but is +insulated from it by a sheet of fiber. The metal strip is set at an +angle, to balance or overbalance, as may be preferred, the magnetic +influence of the exciting coils. The effect of this overbalancing is +shown in Fig. 5, where the full curve represents the current as a +function of the deflection--obtained by comparison with a standard +instrument--and the dotted curve shows what that relation between +deflection and current would be if the law of tangents held good for +these instruments. It will be seen that, about the middle of the scale, +the dotted line coincides nearly with the full line, while at the +extreme end of the scale the dotted line is higher. From this follows, +that if we compare our indicator from which this curve was taken with +any form of tangent instrument showing an equal angle of deflection at +the medium reading, it will be seen that the needle of our indicator +will be deflected to a greater angle at high readings than that of the +tangent galvanometer. Consequently, the divisions on the scale will +be widest apart in our instruments, which greatly facilitates high +readings. + + * * * * * + + + + +SECONDARY BATTERIES. + + +The Consolidated Electric Light Company has now completed the secondary +battery which has for some time engaged the attention of its officers, +and their regular manufacture and use for electric lighting stations +have been fairly entered upon. Among other places to which the batteries +have been sent and put into work is Colchester, where the company +has for some time had an installation at work, chiefly employing +incandescent lamps. The battery consists of lead electrodes, anode and +cathode being of the same character. They are constructed of narrow +ribbons of lead, each element being made from long lengths of the ribbon +about or nearly 0.20 in. width, rolled together into a flat cake like +rolls of narrow webbing, as illustrated by the annexed diagram, Fig. +1, the greater part of the ribbon being very thin and flat; but +intermediate thicker ribbons are also employed, as in Fig. 2, this +thicker ribbon being corrugated as shown, and affording passage room +for the circulation of the electrolyte. From four to eight coils of the +plain ribbons are between every pair of corrugated ribbons. They are +wound up together tightly, and pressed into the nearly rectangular form +shown. The bar for suspending the coil plates so made in the cells is +soldered to the coil. The object of this construction is of course to +obtain large lead surface, and of course a much larger surface is so +obtained than could be practically obtained from plain lead plates in +the same compass. A battery thus made may be seen at the offices of the +company, 110 Cannon Street. + +[Illustration: FIG. 1. FIG. 2.] + +A very ingenious device for cutting the battery out of circuit when +charged as much as is thought desirable is used by the company. In a +cell is an element which has a determined lower capacity than those in +the rest of the battery. Over this element is placed a gas-tight chamber +in which is a diaphgram, this diaphragm being of very flexible material +placed in the cover of the box of cells. When charging has proceeded as +long as is desirable, or proceeds too fast, hydrogen is evolved, and +this collecting in the chamber referred to acts upon the diaphragm, and +by means of a rod connected thereto, switches the current, which is +supplied to an electro-magnet and by which circuit is made through the +medium of mercury contacts. The object, of this is to save the +battery from destruction by over-charging or charging by too large a +current.--_The Engineer_. + + * * * * * + + + + +ACETYLENE FROM IODOFORM. + + +P. CAZENEUVE publishes in the _Comptes Rendus_ a new method for the +preparation of acetylene, which consists in mixing iodoform intimately +with moist and finely divided silver. An abundant evolution of acetylene +takes place without heating. The reaction is represented by the +following formula: 2CHI_{3} + 6Ag = C_{2}H_{2} + 6 AgI. The +decomposition of the iodoform is hastened if the silver is mixed with +finely divided copper, such as can be obtained by precipitating it from +its sulphate by means of zinc. + +Cazeneuve also observed that most metals which have any affinity for +iodine will decompose iodoform in the presence of water, forming +acetylene and an iodide of the metal. By the use of zinc he obtained a +liquid having a pleasant ethereal odor, and a gas mixture that contained +besides acetylene an iodine compound which burned with a purple-edged, +fawn-colored flame. + + * * * * * + + + + +WHEN DOES AN ELECTRICAL SHOCK BECOME FATAL? + + +In this age of electricity and electric wires carrying currents of +various intensity, the question of danger arising from contact with them +has caused considerable discussion. An examination into the facts as +they exist may therefore enlighten some who are at present in the dark. + +To begin with, we often hear the question asked--why is it that certain +wires carrying very large currents give very little shock, whereas +others, with very small currents, may prove fatal to those coming in +contact with them? The answer to this is--that the shock a person +experiences does not depend upon the current _flowing in the wires_, but +upon the current _diverted from them_ and _flowing through the body_. + +The muscular contraction due to a galvanic current, which was first +observed in the frog, gives a good illustration of the fact that it +requires only a very minute current to flow through the muscles in order +to contract them. Thus the simple contact of pieces of zinc and copper +with the nerves generated current sufficient to excite the muscles--a +current which would require a delicate galvanometer for its detection. +What is true of the muscles of the frog holds good also for the human +muscles; they too are very susceptible to the passage of a current. + +In order to determine the current which proves fatal we need only to +apply the formula which expresses Ohm's law, viz., C=E/R, or the current +(ampere) equals the electromotive force (volt) divided by the resistance +(ohm). + +According to the committee of Parliament investigation, the +electromotive force dangerous to life is about 300 volts; this then is +the quantity, E, in the formula. There remains now only to determine the +resistance in ohms which the body offers to the passage of the current. +In order to obtain this, a series of measurements under different +conditions were made. On account of the nature of the experiment a high +resistance Thomson reflecting galvanometer was used, with the following +results. + +When the hands had been wiped perfectly dry, the resistance of the body +was about 30,000 ohms; with the hands perspiring ordinarily it fell to +10,000 ohms; whereas when they were dripping wet it was as low as 7,000 +ohms. Our readers can judge this resistance best when we state that the +Atlantic cable offers a resistance of 8,000 ohms. + +Taking an ordinary condition of the body, with the hands perspiring as +usual, we would have the resistance equal to 10,000 ohms. Applying the +two known quantities in the formula, we get: + + C = (300 / 10,000) - (1 / 33.333+) + +This means, therefore, that when the electromotive force or potential is +great enough to send a current of 1/33 ampere through the body, fatal +results will ensue. This current is so minute that it would deposit only +about 6 _grains_ of copper in _one hour_, a grain being 1/7,000 of a +pound. + +Let us now compare these figures with some actual cases, taking as +an example a system of incandescent lighting. In these systems the +difference of potential between any two points of the circuit outside of +the lamps does not exceed 150 volts. Taking this figure, therefore, it +will be seen that under no circumstances can the shock received from +touching these wires become dangerous--not even by touching the +terminals of the dynamo itself; because in neither case can a current be +driven through the body, sufficient to cause an excessive contraction of +the muscles. + +In a system of arc lighting, however, we have to deal with entirely +different conditions; for, while in the incandescent system the adding +of a lamp, which diminishes the resistance, requires no increase of +electromotive force, the contrary is the case in the arc light system. +Here every additional lamp added to the circuit means an increase in +resistance, and consequent increase in electromotive force or potential. +Taking for example a well known system of arc lighting, we find that the +lamps require individually an electromotive force of 40 volts with a +current of 10 amperes. In other words, the difference in potential at +the two terminals of every such lamp is 40 volts. Consequently, if the +circuit were touched in two places, including between them only one +lamp, no injurious effects would ensue. If we touch the circuit so as +to include two lamps between us, the effect would be greater, since the +potential between those two points is 2 x 40 volts. We might continue +in this manner touching the circuit until we had included about 7 or +8 lamps, when the shock would become fatal, since the point would be +reached at which the difference of potential is great enough to send a +dangerous current through the body. + +Up to this point we have assumed that, while touching two points in the +wire, the rest of the circuit is perfectly insulated, so that no current +can leak, in other words, that the circuit is nowhere "grounded." If +this is not the case we may, under suitable conditions, receive a +shock by touching only _one_ point of the wire. This becomes clear +by considering the current to leak from another spot of different +potential, to pass through the ground and into the body; thus, on +touching the wire the body virtually makes a connection between the +two points of the circuit. In clear dry weather such leaks are +insignificant; but in damp and rainy weather, and with poor insulation, +they may rise to such a point at which it would be dangerous to touch +the circuit even with one hand, the leaks being sometimes so great as +to cause the lamps to burn in a fitful, desultory manner, and to go out +entirely. + +There is still another factor which enters into the discussion of the +danger of electric light wires. This must be looked for in the fact that +the physiological effects are greatest at the moment of the opening or +the closing of the circuit; or in a closed circuit they are the more +marked when the flow of current stops and starts, or diminishes and +increases. In dynamo electric machines the current is not absolutely +continuous or uniform, since the coils on the armature being separated a +distance cause a slight break or diminution of the current between each. +This break is so short that it does not interfere with the practical +work for lighting; in some constructions, nevertheless, the distances +apart is so great that, while not interfering with light, its effects +upon the muscles are greatly increased over those of other constructions +which give a more uniform current. + +All these statements might lead to the conclusion that arc light wires +are dangerous under any circumstances; but this is not the case. The +first and only requisite is, that they be perfectly insulated. When thus +protected accidents from them are impossible, and all mishaps that have +occurred through them can be traced directly to the lack of insulation. +Nevertheless, we would warn our readers against experimenting upon arc +wires by actual trial, because unforeseen conditions might lead to +disagreeable results. + + * * * * * + + + + +ROBERT CAUER'S STATUE OF LORELEI. + + +The statue of Lorelei, the mythical siren of the Rhine, represented in +the annexed cut, which is taken from the _Illustrirte Zeitung_, was +modeled by Robert Cauer, of Kreuglach on the Rhine. He was born at +Dresden in 1831, and is the son of the well-known sculptor Emil Cauer, +and a brother of the sculptor Karl Cauer. + +[Illustration: LORELEI STATUE BY ROBERT CAUER.] + + * * * * * + + + + +REDUCING AND ENLARGING PLASTER CASTS. + + +Ordinary casts taken in plaster vary somewhat, owing to the shrinkage of +the plaster; but it has hitherto not been possible to regulate this +so as to produce any desired change and yet preserve the proportions. +Hoeger, of Gmuend, has, however, recently devised an ingenious method +for making copies in any material, either reduced or enlarged, without +distortion. + +The original is first surrounded with a case or frame of sheet metal or +other suitable material, and a negative cast is taken with some elastic +material, if there are undercuts; the inventor uses agar-agar. The usual +negative or mould having been obtained as usual, he prepares a gelatine +mass resembling the hektograph mass, by soaking the gelatine first, then +melting it and adding enough of any inorganic powdered substance to give +it some stability. This is poured into the mould, which is previously +moistened with glycerine to prevent adhesion. When cold, the gelatine +cast is taken from the mould, and is, of course, the same size as the +original. If the copy is to be reduced, this gelatine cast is put in +strong alcohol and left entirely covered with it. It then begins to +shrink and contract with the greatest uniformity. When the desired +reduction has taken place, the cast is removed from its bath. From +this reduced copy a cast is taken as usual. As there is a limit to the +shrinkage of the gelatine cast, when a considerable reduction is desired +the operation is repeated by making a plaster mould from the reduced +copy, and from this a second gelatine cast is taken and likewise +immersed in alcohol and shrunk. It is claimed that even when repeated +there is no sacrifice of the sharpness of the original. + +When the copy is to be enlarged instead of reduced, the gelatine cast is +put in a cold water bath, instead of alcohol. After it has swollen as +much as it will, the plaster mould is made as before. For enlarging, +the mould could also be made of some slightly soluble mass, and then by +filling it with water the cavity would grow larger, but it would not +give so sharp a copy. + + * * * * * + + + + +STRIPPING THE FILM FROM GELATINE NEGATIVES. + + +We have frequent inquiries as to the best means of removing a +gelatino-bromide negative from its glass support so that it can be used +either as a direct or reversed negative, and it does not appear to be +very generally known that about two years ago Mr. Plener described a +method which answers well under all circumstances, whether a substratum +has been used or not. + +If a negative is immersed in extremely dilute hydrofluoric acid +contained in an ebonite dish, say half a teaspoonful to half a pint of +water, the film very soon becomes loosened, and floats off the glass, +this circumstance being due to the solvent action which the acid +exercises upon the surface of the plate as soon as it has penetrated the +film. If the floating film be now caught upon a plate which has been +slightly waxed, and it is allowed to dry on this plate, it will become +quite flat and free from wrinkles. To wax the plate, it should be held +before the fire until it is moderately hot, after which it is rubbed +over with a lump of wax, and the excess is polished off with a piece +of flannel. When the film is dry, it will leave the waxed glass +immediately, if one corner is lifted by means of a penknife. The film +will become somewhat enlarged during the above-described operation; but, +by taking suitable precautions, this enlargement may be avoided. It is +also convenient to prepare the hydrofluoric acid extemporaneously by the +action of sulphuric acid on fluoride of sodium; and, in many cases, it +is advisable to thicken up the film by an additional layer of gelatine. + +The following directions embody these points. The negative, which must +be unvarnished, is leveled, and covered with a layer of warm gelatine +solution (one in eight) about as thick as a sixpence. This done, and +the gelatine set, the plate is immersed in alcohol for a few minutes +in order to remove the greater part of the water from the gelatinous +stratum. The next step is to allow the plate to remain for five or six +minutes in a cold mixture of one part of sulphuric acid with twelve +parts of water, and in the mean time two parts of sodium fluoride are +dissolved in one hundred parts of water, an ebonite tray being used. A +volume of the dilute sulphuric acid equal to about one-fourth of the +fluoride solution is next added from the first dish, and the plate +is then transferred to the second dish, when the film soon becomes +liberated. When this is the case, it is placed once more in the dilute +sulphuric acid. After a few seconds it is rinsed in water, and laid on a +sheet of waxed glass, complete contact being established by means of a +squeegee, and the edges are clamped down by means of strips of wood held +in position by American clips or string. All excess of sulphuric acid +may now be removed by soaking the plate in methylated alcohol, after +which it is dried. It is as well to add a few drops of ammonia to the +last quantity of alcohol used. + +The plate bearing the film negative is now placed in a warm locality, +under which circumstances a few hours will suffice for the complete +drying of the pellicular negative, after which it may be detached +with the greatest ease by lifting the edges with the point of a +penknife.--_Photo. News_. + + * * * * * + + + + +NEW ANALOGY BETWEEN SOLIDS, LIQUIDS, AND GASES, + +By W. SPRING. + + +The author asks in the first place, What is the cause of the different +specific gravities of one and the same metal according as it has been +cast, rolled, drawn into wire, or hammered? Does the difference observed +prove a real condensation of the matter under the action of pressure, or +is it merely due to the expulsion by pressure of gases which have been +occluded when the ingot was cast? According to well-known researches, +metals such as platinum, gold, silver, and copper, which have +been proved to occlude gases on fusion, and to let them escape, +_incompletely_, on solidification, are precisely those which are +most increased in their specific gravity by pressure. The author has +submitted to pressures of about 20,000 atmospheres metals which possess +this property, either not at all, or to a very trifling extent, and he +finds that though a first pressure produces a slight permanent increase +of density, its repetition makes little difference. Their density is +found to have reached a maximum. Hence the density of solids, like that +of liquids, is only really modified by temperature. Pressure effects +no permanent condensation of solid bodies, except they are capable of +assuming an allotropic condition of greater density. The author's former +researches tend to show that solid matter, in suitable conditions of +temperature, takes the state corresponding to the volume which it is +compelled to occupy. Hence there is an analogy between the allotropic +states of certain solids and the different states of aggregation of +matter. Possibly the different forms of matter may be due to a single +cause--polymerization. The limit of elasticity of a solid body is the +critical moment when the matter begins to flow under the action of the +pressure to which it is submitted, just as, e.g., ice at or below 0 deg. may +be liquefied by strong pressure. A brittle body is simply one which does +not possess the property of flowing under the action of pressure. + + * * * * * + + + + +HYDROGEN AMALGAM. + + +Hydrogen, although a gas, is recognized by chemists as a metal, and when +combined with any solid metal--as in the case known to electricians as +the polarization of a negative element,--the compound may correctly be +termed an alloy; while any compound of hydrogen with the fluid metal +mercury may with equal correctness be termed an amalgam of hydrogen, or +"hydrogen amalgam." The efforts of many chemists and mining engineers +have for many years been devoted to a search for some effective and +economical means for preventing the "sickening" of mercury and its +consequent "flouring" and loss. Some sixteen or more years ago, +Professor Crookes, F.R.S., discovered and, after a series of +experiments, patented the use of an amalgam of the metal sodium for this +purpose. He made the amalgam in a concentrated form, and it was added +in various proportions to the mercury used for gold amalgamation. Water +becoming present, it will readily be understood that the sodium, in +being converted into the hydrate (KHO) of that metal, caused a rapid +evolution of hydrogen. The hydrogen thus evolved was the excess over a +certain proportion which enters into combination with the mercury. While +the mercury retained the charge of hydrogen, the "quickness" of the +fluid metal was preserved; but upon the loss of the hydrogen the +"quickness" ceased, and the mercury was acted upon by the injurious +components contained in the ore. + +Since the introduction of the sodium amalgam, many attempts have been +made, more especially in America, to overcome the tendency of mercury to +"sicken" and lose its "quickness." The greater number of these efforts +have been made by the use of electricity as the active agent in +attaining this end; but such efforts have been generally of a crude and +unscientific character. Latterly Mr. Barker, of the Electro-amalgamator +Company, Limited, has introduced a system--already detailed in these +pages--by which the mercury is "quickened." In his method the running +water passing over the tables, or other apparatus of a similar +character, is used as the electrolyte. In this arrangement, the mercury +being the cathode, plates or wires of copper constituting anodes are +brought into contact with the water passing over the mercury in each +"riffle." Both the cathode and the anodes are, of course, maintained in +contact with the poles of a suitable source of electrical supply. The +current then passes from the copper anode through the running water +to the mercury cathode, and so on to the negative pole of the +electro-motor. As a consequence of this arrangement, hydrogen is evolved +from the water, and has the effect of reducing any oxide or other +detrimental compound of the metal; in other words, it "quickens" and +prevents "sickening" of the fluid metal, and consequent "flouring" and +loss. While the hydrogen is evolved at the cathode, oxygen enters into +combination with the copper constituting the anodes. This to some extent +impairs the conductivity of the circuit. + +The latest process, however, is that of Mr. Bernard C. Molloy, M.P., +which we have already characterized as highly scientific and effective, +the production of a suitable amalgam being obtained under the most +economical and simple conditions. This process has the advantage of +producing not only a hydrogen amalgam, but also at will an amalgam of +hydrogen combined with any metal electro-positive to this latter. Thus +hydrogen potassium or hydrogen sodium can be obtained, as will be seen +by the following description. + +Mr. Molloy's effort appears to have been, in the first place, directed +to a system which could be adapted to any existing apparatus, and in +certain cases where water was scarce, to avoid altogether the use of +that, in some districts, rare commodity. For the purpose of explanation +we select an ordinary amalgamating table fitted with mercury riffles. +The surface of the table is in no way interfered with or disturbed. The +bed of the riffle, however, is constructed of some porous material, such +as leather, non-resinous wood, or cement, which serves as the diaphragm +upon which the mercury rests, and separates the fluid metal from the +electrolyte beneath. Running the full length of the table is a thin +layer of sand, supported and pressing against the diaphragm, and lying +in this sand is the anode, formed preferably of lead. A peroxide of +that metal is formed by the action of the currents, and may be readily +reduced for use over and over again after working for from one to three +months. The peroxide of lead, as is well known, is a conductor of +electricity, and this fact constitutes an important advantage in the +working of the process. The thin layer of sand is saturated with an +electrolyte, such as dilute sulphuric acid (H_{2}SO_{4} + 20H_{2}O) +to give a simple hydrogen amalgam; (Na_{2}SO_{4} + xH_{2}O) to give a +hydrogen sodium amalgam; or (K_{2}SO_{4} + xH_{2}O) to give a hydrogen +potassium amalgam. Numerous other electrolytes constituted by acids, +alkalies, and salts can be used to form an amalgam permanently +maintained in a condition of "quickness" and freed from all liability +to "sicken," whatever the components of the ore may be. The mercury +is connected with the negative pole of the voltaic battery or other +electro-motor, and the lead made with the positive pole of the same +source. When the current passes there is formed according to the nature +of the electrolyte, a hydrogen amalgam, or an amalgam of hydrogen with a +metal electro-positive to hydrogen. The electrolyte, which, it will be +understood, is distinct and apart from the body of water passing over +the table, will last almost indefinitely, there being no consumption of +any of its constituents, excepting hydrogen and oxygen from the water +of solution. The quantity of acid or saline material contained in the +electrolyte is so very small that there can be no difficulty in finding +a supply in any district. The question of the supply of electricity is +one which in many mining districts involves considerations of practical +importance, since a large supply would necessitate water or steam power. +It has been found that two cells having an electromotive force of about +two volts each will in this process suffice; if preferred, however, +a very small dynamo machine can be used. In connection with the +electro-motive force it is requisite to use, it may be observed that an +amalgam of sodium containing only a small quantity of this metal would, +when constituting a positive element in conjunction with a lead negative +and on an aqueous electrolyte, give an opposing electro-motive force of +less than three volts. Such an amalgam could therefore be obtained under +an electro-motive force of about four volts. The electrical resistance +in the circuit constituted by the apparatus being very small, no +electrical power is wasted. When water constitutes the electrolyte, as +in Barker's system, then the electro-motive force required to obtain a +given current would be very much greater than that above specified. +The conditions assured under this process appear to be all that can +be required, while the amalgams obtained are those most calculated to +preserve the "quickness" and prevent the "sickening" of the mercury. + +Mr. Molloy has designed a special form of amalgamating machine to be +used in conjunction with the above process, and with or without the aid +of water. By the employment of this machine, each particle of the ore +is slowly rolled in the quickened mercury for from fifteen to thirty or +more seconds. + +When the extent of the gold and silver mining industries is considered, +and when it is borne in mind that a considerable percentage of the +precious metal present in the ore is, in the ordinary process of +extraction, lost through defective amalgamation--due to insufficient +contact with the mercury or to a total absence of contact, as in the +case of float gold--it is obvious that the introduction of any system +obviating such loss is a matter of very great importance to those who +are interested in the above mentioned industries. We expect shortly to +hear of the practical introduction on a large scale of Mr. Molloy's +process, and we look forward with interest to the results which may be +obtained from it.--_The Engineer_. + + * * * * * + + + + +TREATMENT OF ORES BY ELECTROLYSIS. + +By M. KILIANI. + + +The author lays down general principles for electrolytic metallurgy. +Ores must be distinguished as good and bad conductors; the former +may serve directly as anodes, and are easily oxidized by the +electro-negative radicals formed at their contact, and dissolve readily +in the electrolyte. The bad conductors have to be placed in contact +with a conducting anode, formed of an inoxidizable substance, such as +platinum, manganese peroxide, or coke. In laboratory experiments a good +conducting ore is electrolyzed by suspension from a platinum wire in +connection with the source of electricity, and is then immersed in the +bath. On an industrial scale the ore, coarsely broken up, is placed in +one of the compartments of a trough divided by a diaphragm. + +On the fragments of the ore which extend up outside of the electrolytic +bath is laid a plate of copper connected with the positive wire. Care +must be taken that this plate does not plunge into the bath, otherwise +the current would not traverse the ore at all. The cathode is preferably +formed of the same metal which is to be obtained. The bath should +not contain organic acids. In practice the common mineral acids are +employed, or their salts, selecting by preference a salt of the metal +which is to be isolated. It is convenient to pass the current through +the greatest possible number of small decomposition troughs, taking care +that the resistance in each is not too great. With a current of one and +the same intensity we obtain in n troughs n times as much metal as in a +single one. To keep down the resistance of the circuit we employ poles +of a large surface, i.e., plenty of ore and baths which are as good +conductors as possible. + +The state in which the metal is deposited at the negative pole depends +on the secondary actions undergone by the electrolyte, and especially of +the escape of gas. This is a function of the _density_, of the current, +i.e., the proportion of its intensity to the surface of the cathode. If +the density is too great there is an escape of hydrogen, and the metal +is deposited in a spongy condition. If the density of the current falls +below a certain minimum, an oxide is deposited in place of metal. The +electrolytic treatment of ores often renders it possible to separate +the different metals which may be present. These are deposited in +succession, and are sharply separated if the electromotive power is not +too great. + +1. _Zinc_.--The zinciferous compounds--calamine, blende, and zinc +ash--are all poor conductors. They are first dissolved, and the salts +obtained are electrolyzed, employing anodes of coke. Blende should be +roasted before it is dissolved. The electrolytic bath should be as +concentrated as possible to avoid sponginess of the metal and an escape +of hydrogen. In a saturated solution the formation of hydrogen decreases +as the density of the current augments. + +2. _Lead_.--Galena is a good conductor, and may be directly +electrolyzed. The best bath is a solution of lead nitrate. The +arborescent crystallizations extend rapidly, and must be broken from +time to time to prevent the formation of a metallic connection between +the anode and the cathode. The sulphur of the galena falls to the bottom +of the bath, and may be separated from the gangue by solution in carbon +disulphide. + +3. _Copper_.--Native copper sulphide, though a good conductor, cannot +be directly electrolyzed en account of the presence of iron sulphide, +whence iron would be deposited along with the copper. The copper pyrites +are roasted, dissolved in dilute sulphuric acid, and the liquid thus +obtained is submitted to electrolysis. + + * * * * * + + + + +A PEOPLE WITHOUT CONSUMPTION, AND SOME ACCOUNT OF THEIR COUNTRY--THE +CUMBERLAND TABLELAND. + +By E. M. WIGHT, M.D., Chattanooga, Tenn., Late Professor of Diseases +of the Chest and State Medicine, Medical Department University of +Tennessee; Late Member of the Tennessee State Board of Health, and +ex-President of the Tennessee State Medical Society. + + +During the ten years that I have practiced medicine in the neighborhood +of the Cumberland Tablelands, I have often heard it said that the +people on the mountains never had consumption. Occasionally a traveling +newspaper correspondent from the North found his way down through the +Cumberlands, and wrote back filled with admiration for their grandeur, +their climate, their healthfulness, and almost invariably stated that +consumption was never known upon these mountains, excepting brought +there by some person foreign to the soil, who, if he came soon enough, +usually recovered. Similar information came to me in such a variety of +ways and number of instances, that I determined some four years ago, +when the attempt to get a State Board of Health organized was first +discussed by a few medical men of our State, that I would make an +investigation of this matter. These observations have extended over that +whole time, and have been made with great care and as much accuracy +as possible, and to my own astonishment and delight, I have become +convinced that pulmonary consumption does not exist among the people +native and resident to the Tablelands of the Cumberland Mountains. + +In the performance of the work which has enabled me to arrive at this +conclusion, I have had the generous assistance of more than twenty +physicians, who have been many years in practice in the vicinity of +these mountains. Their knowledge of the diseases which had occurred +there extended over a, period of more than forty years. Some of these +physicians have reported the knowledge of the occurrence of deaths from +consumption on the Tablelands, but when carefully inquired into they +have invariably found that the person dying was not a native of the +mountains, but, a sojourner in search of health. In answer to the +question: "How many cases of pulmonary consumption have you known to +occur on Walden's Ridge, among the people native to the mountains?" +eleven physicians say, "Not one." All of these have been engaged in +practice there more than three years, four of them more than ten years, +one of them more than twenty, and one of them more than forty years. All +the physicians of whom inquiries have been made are now residents, or +have been, of the valleys contiguous to Walden's Ridge, and know the +mountain people well. Four other physicians in answer to the same +question say, that they have known from one to four cases, numbering +eleven in all, but had not ascertained whether five of them were born +and raised on the mountains or not. The names and place of death of all +these cases were given, and I have traced their history and found that +but three of them were "natives," or had lived there more than five +years, and that one of these was 57 years of age when she died, and had +suffered from cancer for three years before her death. The two others +died within six months after returning home from long service in the +army, where both contracted their disease. + +All these investigations have been made with more particular reference +to that part of the Cumberlands known as Walden's Ridge than to the +mountains as a whole. This ridge is of equal elevation and of very +similar character to the main Cumberland range in the southern part of +Tennessee, northwest Georgia, and northwest Alabama, and what is true of +this particular part of the great Cumberland table is, in the main, true +of the remainder. + +Sequatchee Valley lies between Walden's Ridge and what is commonly known +in that neighborhood as the Cumberland Mountains, and separates it from +the main range for a distance of about one hundred miles, from the +Tennessee River below Chattanooga to Grassy Cove, well up toward the +center line of the State. Grassy Cove is a small basin valley, which +was described to me there as a "sag in the mountains," just above the +Sequatchee Valley proper. It is here that the Sequatchee River rises, +and flowing under the belt of hills which unites the ridge and the main +range, for two miles or more, rises again at the head of Sequatchee +Valley. Above Grassy Cove the mountains unite and hold their union +firmly on their way north as far as our State reaches. + +Topographically considered as a whole, the Cumberland range has its +southern terminus in Alabama, and its northern in Pennsylvania. It +is almost wholly composed of coal-bearing rocks, resting on Devonian +strata, which are visible in many places in the valleys. + +But a small portion of the Cumberland lies above a plane of 2,000 feet. +Walden's Ridge and Lookout Mountain vary in height from 2,000 to 2,500 +feet. + +North of Grassy Cove, after the ridges are united, the variation from +2,000 feet is but little throughout the remainder of the State, and +the general character of the table changes but little. The great and +important difference is in the climate, the winters being much more +severe in these mountains in the northern part of the State than in the +southern, and the summers much more liable to sudden changes of weather. +Scott, Fentress, and Morgan counties comprise this portion of the table, +and these have not been included in my examination, excepting as to +general features. + +In all our southern country, and I may say in our whole country, there +is no other large extent of elevated territory which offers mankind +a pleasant living place, a comfortable climate--none too cold or too +hot--and productive lands. We have east of the upper waters of the great +Tennessee River, in our State, and in North Carolina and Georgia, the +great Blue Ridge range of mountains, known as the Unaka, or Smoky, +Chilhowee, Great and Little Frog, Nantahala, etc., all belonging to the +same family of hills. This chain has the same general course as the +Cumberlands. It is a much bolder range of mountains, but it is vastly +less inhabitable, productive, or convenient of access. The winters there +are severely cold, and the nights in summer are too cold and damp for +health and comfort, as I know by personal experience of two summers on +Nantahala River. But the trout fishing is beyond comparison, and that +is one inducement of great value for a stout consumptive _who is a good +fellow_. These mountains are much more broken up into branches, peaks, +and spurs than the Cumberlands. They afford no table terrritory of +any extent. There are some excellent places there for hot summer +visits--Ashville, Warm Springs, Franklin, and others. + +The Cumberland Mountains, as a whole, are flat, in broad level spaces, +broken only by the "divides," or "gulfs," as they are called by the +inhabitants, where the streams flow out into the valleys. + +Walden's Ridge, of which we come now to speak particularly, is the best +located of any part of the Cumberlands as a place for living. From the +separation of this ridge from the main range of Grassy Cove to its +southern terminus at the Tennessee River, it maintains a remarkably +uniform character in every particular. From it access to commerce is +easy, having the Tennessee River and the new (now building) Cincinnati +Southern Railroad skirting its entire length on the east. It rises very +abruptly from both the Tennessee and Sequatchee Valleys, being from +1,200 to 1,500 feet higher than the valleys on each side. Looking from +below, on the Tennessee Valley side, the whole extent of the ridge +appears securely walled in at the top by a continuous perpendicular wall +of sandstone, from 100 to 200 feet high; and from the Sequatchee side +the appearance is very similar, excepting that the wall is not so +continuous, and of less height. + +The top of the ridge is one level stretch of plain, broken only by the +"gulfs" before mentioned and an occasional prominent sandstone wall or +bowlder. The width on top is, I should judge, 6 or 7 miles. The soil is +of uniform character, light, sandy, and less productive for the ordinary +crops of the Tennessee farmer than the soil of the lowlands. The grape, +apple, and potato grow to perfection, better than in the valleys, and +are all never failing crops; so with rye and buckwheat. Corn grows +well, very well in selected spots, and where the land is made rich +by cultivation. The grasses are rich and luxuriant, even in the wild +forests, and when cultivated, the appearance is that of the rich farms +of the Ohio or Connecticut Rivers, only here they are green and growing +the greater part of the year; so much so that sheep, and in the mild +winters the young cattle, live by the wild grasses of the forests the +whole year. The great stock raisers of the Sequatchee and Tennessee +Valleys make this the summer pasture for their cattle, and drive them to +their own farms and barns or to market in winter. The whole Cumberland +table, with the exception of that small part which is under cultivation, +is one great free, open pasture for all the cattle of the valleys. +Thousands of cattle graze there whose owners never pay a dollar for +pasturage or own an acre of the range, though, as a rule, most of the +well-to-do stock farmers in the valleys own more or less mountain lands. +These lands have, until quite recently, been begging purchasers at from +121/2 to 25 cents per acre in large tracts of 10,000 acres and upward, and +perhaps the same could be said of the present time, leaving out choice +tracts and easily accessible places, which are held at from 50 cents to +$2 per acre, wooded virgin lands. + +The forest growth of Walden's Ridge is almost entirely oak and chestnut. +Hickory, perhaps, comes next in frequency, and pine after. There is but +little undergrowth, and where the forests have never been molested there +are but few small trees. This is due to the annual fires which occur +every autumn, or some time in winter, almost without exception, and +overrun the whole ridge. It does not rage like a prairie fire. Its +progress is usually slow, the material consumed being only the dry +forest leaves and grasses. The one thing essential to its progress is +these dry leaves, hence it cannot march into the clearings. Nearly all +the small shrubs are killed by these fires, otherwise they are harmless, +and are greatly valued by the stock men for the help they render in the +growth of the wild grasses. The free circulation of air through these +great unbroken forests is certainly much facilitated by these fires, +since they destroy every year what would soon become impediments. The +destruction of this undergrowth leaves the woods open, and the lands are +mainly so level that a carriage may be driven for miles, regardless of +roads, through the forests in every direction. + +The shrubs about the fields and places where the forests have +been interrupted by civilization and other causes are blackberry, +huckleberry, raspberry, sumac, and their usual neighbors, with the +azalia, laurel, and rhododendron on the slopes and in the shade of the +cliffs. + +The kinds of wild grasses, I regret to say, I have not noted, and the +same of the rich and varied display of wild flowers. + +The whole ridge is well supplied with clean, soft running water, even +in the driest of the season. There are no marshes, swamps, or bogs, no +still water--not even a "puddle" for long--for the soil is of such a +character, that surface water quickly filters away into the sands and +mingles with the streams in the gulfs. Springs of mineral water are +abundant everywhere. Probably there is not a square mile of Walden's +Ridge which does not furnish chalybeate water abundantly. Sulphur +springs with Epsom salts in combination are nearly as common. + +The entire extent of Walden's Ridge is underlaid with veins of coal, and +iron ore is plentiful, especially in the foot hills. The coal and iron +are successfully mined in many places on the eastern slope; on the +western they are nearly untouched for the want of transportation. I find +that the impression prevails that the minerals of the Cumberlands are +largely controlled by land agents and speculators. This is only true as +applied to a very small part of the whole, not more than 1 per cent. The +mineral ownership remains with the lands almost entirely. + +The prevailing winds on Walden's Ridge are from the southwest; northers +and northeasters are of rare occurrence. One old lady who had resided +there for forty years, in answer to my query upon this subject, said: +"Nine days out of ten, the year round, I can smell Alabama in the air." +This was the usual testimony of the residents. Winds of great velocity +never occur there. In summer there is always an evening breeze, +commencing at 4 to 6 o'clock, and continuing until after sunrise +the next morning. In times of rain, clouds hang low over the ridge +occasionally, but they never have fogs there. + +The range of the thermometer is less on the Tablelands than in the +adjacent valleys. I have had access to the carefully taken observations +of the Lookout Mountain Educational Institute, such published accounts +as have been made by Professor Safford, State Geologist, Mr. Killebrew, +the thorough and painstaking private record of Captain John P. Long, +of Chattanooga, and many more of less length of time. From all these I +deduce the fact that the summer days are seven or eight degrees cooler +on the mountains than in the Tennessee Valley at Chattanooga, and five +or six degrees cooler than in the Sequatchee Valley, as far up as Dunlay +and Pikeville. The nights on the table are cooler than in the lower +lands by several more degrees than the days; how much I have thus far +not been able to state. The late fall months, the winter, and early +spring are not so much colder than the valleys as the summer months, the +difference between the average temperature of the mountains and valleys +being at that time four or five degrees less than in the summer. There +is no record of so hot a day ever having occurred on the Cumberladd +Mountains as to cause mercury to run so high as 95 deg. F., or so cold a day +as to cause it to run so low as 10 deg. below zero. + +In the average winter the ground rarely freezes to a greater depth than +2 or 3 inches, and it remains frozen but a few days at a time. Ice has +been known to form 8 inches thick, but in ordinary winters, 3 or 4 +is the maximum. Snow falls every winter, more or less, and sometimes +remains for a week. Old people have a remembrance of a foot of snow +which lasted for a week. + +Walden's Ridge has a total population of a little more than 4,000, +scattered over 600 square miles of surface. The number of dwellings is +about 800. Ninety per cent. of these are log houses; 70 per cent. of +them are without glass windows; light being furnished through the +doorways, always open in the daytime, the shuttered window openings, and +the open spaces between the logs of the walls. Less than 2 per cent. of +these houses have plastered walls or ceilings, and less than 5 per cent. +have ceiled walls or ceilings. About 20 per cent. of them are fairly +well chinked with clay between the logs, the remainder being but +indifferently built in that particular. Fully 90 per cent. of these +abodes admit of free access of air at all times of day and night, +through the floors beneath as well as the walls and roof above. It is +the custom of the people to guard against the coldest of days and nights +by hanging bed clothes against the walls, and many good housewives have +a supply of tidy drapery which they keep alone for this purpose. + +Wood, always at hand, is the only fuel in use. The whole heating +apparatus consists in one large open fireplace, built of stone, +communicating with a large chimney outside the house at one end, and +frequently scarcely as high as the one story building which supports it. +This chimney is constructed in such a manner as to be a great ventilator +of the whole room, quite sufficient, it would be thought, if there were +no other means of ventilation. It is usually made of stone at the +base, and that part above the fire is of sticks laid upon one another, +cobhouse fashion, and plastered over inside and between with similar +clay as that with which the house walls are chinked. + +Very few of these houses are more than one story high. They are all +covered with long split oak shingles--the people there call them +"boards"--rifted from the trunks of selected trees. There is no +sheathing on the roof beneath these shingles. They are nailed down upon +the flat hewn poles running across the rafters, at convenient distances. +Looking up through the many openings in the roof in one of these house, +one would think that this would be but poor protection against rain, but +they rarely leak. + +Not one family in fifty is provided with a cooking stove. They bake +their bread in flat iron kettles, with iron covers, covered with hot +coals and ashes. These they call ovens. The meat is fried, with only the +exception of when accompanied by "turnip greens." + +The question, "What is the principal food of the people who live on +these mountains?" has been asked by me several hundred times. The +almost invariable answer has been, "Corn bread, bacon, and coffee." +Occasionally biscuits and game have been mentioned in the answers. All +food is eaten hot. Coffee is usually an accompaniment of all three +meals, and is drunk without cream and often without sugar. Some families +eat beef and mutton for one or two of the colder months in the year on +rare occasions, though beef is commonly considered "onfit to go +upon," as I was told upon several occasions, and mutton sustains less +reputation. Chickens are used for food while they are young and tender +enough to fry, on occasions of quarterly meetings, visits of "kinfolks" +or the "preachers" and the traveling doctors. Fat young lambs are plenty +in many settlements from March to October, and can be had at fifty cents +each, but I could not learn that one was ever eaten. + +A large majority of the adult population use tobacco in some shape--the +men by chewing or smoking, the women by smoking or dipping snuff. They +never have dyspepsia, nor do they ever get flesh, after they pass out of +childhood, though nearly all the children are ruddy in appearance, and +well rounded with fat. + +One physical type prevails among the people in middle life, and carries +along into old age but little change; and old age is common there. +Nearly every house has its old man or old woman, or both. Everybody, +father and mother, and frequently grandfather and grandmother, is still +on hand, looking as brisk and moving about as lively as the newer +generations. After they pass their forty years, they never seem to +grow any older for the next twenty or thirty, and the grandfathers and +grandmothers can scarcely be selected, by comparison, from their own +children and grandchildren. The men are taller than the average, and +the women, relatively, taller than the men. They are all thin featured, +bright eyed, long haired, sharp looking people, with every appearance of +strength and power of endurance. + +I think the men who live on Walden's Ridge can safely challenge the +world as walkers--aborigines and all; and unless the challenge should be +accepted by their own women folks, I feel quite sure they would "win the +boots." They go everywhere on foot, and never seem to tire. + +Nearly all the people of the Tablelands are employed in the pursuits of +agriculture. Very few of them seem to be hard workers. The men are all +great lovers of the forest sports, much given to the good, reliable, old +fashioned long rifles. The women and children are much employed in out +door occupations, and live a great portion of their time in the open +air. The clothing of all classes is scanty. The use of woolen fabrics +for underwear has not yet been introduced, and coarse cotton domestic +is the universal shirting, and cotton jeans, or cotton and wool mixed, +constitute the staple for outer wearing apparel. The men wear shoes +throughout the year much more commonly than boots. They never wear +gloves, mittens, scarfs, or overcoats, and they scorn umbrellas. +Probably this whole 4,000 people do not possess two dozen umbrellas or +twice as many overcoats. The women go about home with bare feet a great +part of the summer. They never wear corsets or other lacing. + +I have learned by careful inquiry that very few of the people of the +Ridge have ever had the diseases of childhood. Scarlet fever I could +hear of in but two places, and I suppose that not one person in fifty +has had it. Whooping cough and measles have occurred but rarely, and the +large majority have not yet experienced the realities of either. Very +few people there have ever been vaccinated, nor has smallpox ever +prevailed. Typhoid, typhus, and intermittent fevers are unknown. In the +great rage of typhoid fever which took place ten or twelve years ago in +the Tennessee and Sequatchee Valleys, not a single case occurred on the +Mountains, as I have been informed by physicians who were engaged in +practice in the neighborhood at the time. Diphtheria has never found a +victim there; so of croup. Nobody has nasal catarrh there, and a cough +or a cold is exceedingly rare. + +I have said that these observations refer more particularly to Walden's +Ridge than to the Cumberland Tablelands in our State as a whole. This +ridge was chosen by me for this examination, mainly for the reason of +its convenience, but partly owing to its being more generally settled +than any other equal portion of the table which lies in Tennessee. +Lookout Mountain is not as well located; it is on the wrong side of the +Tennessee River, and but a few acres of it belong in this State. Sand +Mountain is altogether out of the State, but it is perhaps nearer like +Walden's Ridge in its physical features than Lookout. That part of the +Cumberlands west of Sequatchee Valley is Walden's Ridge in duplicate, +excepting that it is further west, and nearer the Middle Tennessee +basin. There are some small towns, villages of miners, and summer +resorts there, which interferes with that evenness of the distribution +of population which Walden's Ridge has, rendering it more liable to +visitations of epidemic and contagious diseases. The tablelands north +of the center line of the State, above Grassy Cove, are very similar +to Walden's Ridge, as far up as Kentucky, with the exception before +mentioned--that of climate--it being from one to ten degrees colder in +winter. + +This whole Cumberland Table is no small country. It comprises territory +enough to make a good sized State. At present, it is almost one great +wilderness, in many particulars as unknown as the Black Hills. It is +coming into the world now, and will be well known in a few years. The +great city of Cincinnati has determined to build a railroad through +the very center of this great table in the north part of the State, +connecting with Chattanooga in the southern part. This road is nearly +bored through, and in another year or two the Cumberland Tablelands in +Tennessee will be much heard of at home and abroad. + +It seems to me this country has merits. It is located in the latitude of +mild climate; not so far south as to be scorched by the hot summer sun, +or visited by the great life destroying epidemics; not so far north as +to meet the severe and lengthened winters. + +Climate, we know, is a fixture; it has a government; it has rules; the +weather may change, but climate does not; it is a permanent out-door +affair, and what is true of to-day was true centuries ago, and will +be true forever, in the measure of any practical scope, at least. The +people of the world are beginning to know that the greatest destroyer of +human life has its remedy in climate. + +Mr. Lombard, in his famous exhibit in relation to the prevalence of +consumption among the people of different occupations, circumstances of +life, and place of dwelling, gives the lowest number of deaths from this +cause to those who live in the open air. He found the people who lived +most in the open air, as would be readily conjectured, in the mild +latitudes, not in the countries of hot sands or cold snows. + +[The above article, in regard to which we have noticed frequent +allusions in many of our exchanges, all erroneously attributing it to +_Dr. Wright_, of Tennessee, and for which we have received repeated +requests quite recently, was read by the lamented Dr. E.M. Wight at +the 43d annual meeting of the Tennessee State Medical Society, held +at Nashville, April 4, 5, and 6, 1876. Its distinguished and talented +author will long be remembered as one of the most active, earnest, and +zealous members of the State Society. At this meeting he also read a +very admirable paper on "The Microscopic Appearance of the Blood in +Syphilis," and prepared the report of the Committee on State Board +of Health, to which report may be ascribed the honor of securing the +necessary legislation organizing the Board. A true, upright, honest man, +an earnest, devoted and zealous physician, universally esteemed and +beloved by all who knew him; himself the subject of tuberculosis, dying +in the prime of a brilliant manhood. He had but few equals in the +glorious profession he honored and loved so well. + +From a careful reading of his paper, we find that he describes a large +area of territory, free, absolutely free, from subsoil moisture, a +climate mild and equable, a soil capable of producing nearly everything +necessary for the comfortable maintenance of human life, surroundings +that tempt, nay, compel the greatest possible amount of open air +life. His description is exceedingly accurate of a plain, primitive, +simple-minded people with but few wants, many of the virtues and few +of the vices of humanity. With their surroundings, soil, climate, +residence, and mode of living, need we be surprised that "there is +a people," or a land "free from consumption"?--ED.]--_Southern +Practitioner_. + + * * * * * + + + + +THE TREATMENT OF HABITUAL CONSTIPATION. + + +Dr. F.P. Atkinson thus writes in the _Practitioner_, January, 1884: I +suppose there is no derangement of the system we are more frequently +called upon to treat than habitual constipation; and though all kinds of +medicines are suggested for its relief, they rarely produce more than +temporary benefit--and it is difficult to see how the result can well be +otherwise, while the root of the evil remains untouched. Now by far the +more numerous subjects of this disorder are women; and as they do not +seem to know that regularity is essential to the performance of every +one of nature's operations, they appoint no stated times for trying to +get the bowels relieved, but trust to receiving intimation when the +rectal accumulation and distension can be borne no longer. This method +of action may and does answer fairly well for a time; but nature +gradually gets upset, the sensation of the lower bowel becomes blunted, +and at last it ceases to respond to the ordinary stimulus. Then +aperients are regularly resorted to, and although these act fairly +well for a time, they gradually have to be increased in strength +and frequency. Now, as regards the treatment, the first thing to be +accomplished is of course to get the rectum well relieved; the next, +to get the actions to take place at fixed times; and lastly, it is +necessary to get more tone imparted to the muscular tissue of the +bowels, so that the regularity of action may be helped and also +maintained. In order, then, to get the bowels relieved in the first +instance, it is well to give five grains of both compound colocynth and +compound rhubarb pill at bed-time (this rarely requires to be repeated), +then to take a tumblerful of cold water the next morning on waking, and +repeat it regularly at the same time each day. Should the bowels remain +sluggish for some time, the same quantity of water may be taken daily +before each meal. Supposing no action takes place on rising or shortly +after, a small injection of warm water may be resorted to. After each +movement of the bowels, a small hand-ball syringeful of _cold_ water +should be thrown into the rectum and retained. A soup plateful of coarse +oatmeal porridge (made with water and taken according to the Scotch +method, viz., by filling half the spoon with the hot porridge and the +other with cold milk) each night at bed-time, or even every night and +morning for a time, is often a very great help. But above all things, +it is necessary for the patient to _try_ and get relief at a certain +_fixed_ time regularly every day. If these directions are strictly +carried out in their entirety, the evil, even if it has been of long +standing, will generally be corrected, and the patient will improve in +health and appearance. Of course where the constipation results from +exhaustion of the nervous system (such, for instance, as is brought +about by self-abuse), the special cause has to be taken into +consideration, and such treatment adopted as is suited to the particular +necessities of the case. + + * * * * * + + + + +THE PYRAMIDS OF MEROE. + + +About fifty miles from the mouth of the Atbara, and, of course, on the +eastern bank of the Nile, stand the pyramids of Meroe. They consist +of three groups, and there are, in all, about eighty pyramids. The +presumption is that they represent the old sepulchers of the kings of +Meroe. Candance, Queen of the Ethiopians, mentioned in Acts, chap. +viii., v. 27, is supposed to have belonged to Meroe, that being the name +also of the capital, which is understood to have been somewhere not far +distant from the sepulchers. These pyramids of Meroe possess one marked +feature, distinguishing them from the pyramids of Egypt proper--that is, +they have an external doorway or porch. As there is no entrance to the +pyramid at these porticoes, it is quite possible that they were temples +for worship or making offerings to the dead. By comparing them with +the pyramids of Ghizeh, it will be seen that they are also taller in +proportion to their base. Another important point in these porches +or temples is the existence of the arch; and that, too, an arch in +principle, with a keystone.--_Illustrated London News_. + +[Illustration: THE PYRAMIDS OF MEROE, ON THE NILE.] + + * * * * * + + + + +THE PROLIFICNESS OF THE OYSTER. + + +In an article by Prof. Karl Mobius on "The Oyster and Oyster Culture," +reproduced in the recently issued report of the U. S. Commissioner of +Fish and Fisheries, the author says: + +A mature egg-bearing oyster lays about one million of eggs, so that +during the breeding season there are upon our oyster beds at least +2,200,000,000,000 young oysters, which surely would suffice to transform +the entire extent of the sea-flats into an unbroken oyster bed; for if +such a number of young oysters should be distributed over a surface 74 +kilometers long by 22 broad, 1,351 oysters would be allotted to every +square meter. But this sum of 2,200,000,000,000 young oysters is +undoubtedly less than that in reality hatched out, for not only do those +full-grown oysters which are over six years of age spawn, but they begin +to propagate during their second or third year, although it is true that +the young ones have fewer eggs than those which are fully developed. At +a very moderate estimation, the total number of three to six year old +oysters which lie upon our beds will produce three hundred billions of +eggs. This number added to that produced by the five millions of full +grown oysters would give for every square meter of surface not merely +1,351 young oysters, but at least 1,535. In order to determine how +many eggs oysters produce, they must be examined during their spawning +season. This begins upon the Schleswig-Holstein beds in the middle of +June, and lasts until the end of August or beginning of September. The +spawning oyster does not allow its ripe eggs to fall into the water, as +do many other mollusks, but retains them in the so-called beard, the +mantle, and gill-plates until they become little swimming animals. The +eggs are white, and cover the mantle and gill-plates as a semi-fluid, +cream-like mass. As soon as they leave the generative organs the +development of the germ begins. The entire yolk-mass of the egg divides +into cells, and these cells form a hollow, sphere-like body, in which an +intestinal canal arises by the invagination of one side. Very soon the +beginnings of the shell appear along the right and left sides of the +back of the embryo, and not long afterward a ciliated pad, the velum, is +formed along the under side. This velum can be thrust out from between +the valves of the shell at the will of the young animal, and used by the +motion of its cilia as an organ for driving food to the mouth, or +in swimming as a rudder. During these transformations the original +cream-white color of the germ changes into pale gray, and finally into a +deep bluish-gray color. At this time they have a long oval outline, and +are from 0.15 to 0.18 of a millimeter in breadth. Over 300,000 can find +room upon a square centimeter of surface. If an oyster in which the +embryos are in this condition is opened, there will be found upon its +beard a slimy coating thickly loaded with grayish-blue granules. These +granules are the embryo oysters, if a drop of the granular slime be +placed in a dish with pure sea water, the young animals will soon +separate from the mass, and spread swimming through the entire water. +When the embryos are at this stage their number may be estimated in the +following manner: The whole mass of embryos is carefully scraped from +the beard of the mother oyster by means of a small hair brush. The whole +mass is then weighed, and afterward a small portion of the mass. This +small portion is then diluted with water or spirits of wine, and the +embryos portioned out into a number of small glass dishes, so that they +can be placed under the microscope and counted. Thus, knowing the weight +of the small portion and the number of embryos in it by count, we can +estimate the total number of embryos from the weight of the entire mass, +which is also known. In this manner I estimated the number of embryos +in each of five full grown Schleswig-Holstein oysters caught in August, +1869, and found that the average number was 1,012,956. + +Notwithstanding this great fecundity, but an extremely small proportion +of the young oysters produced during the course of the summer arrive +at maturity, 421 only out of 500,000,000 escaping destruction. The +immolation of a vast number of young germs is the means by which nature +secures to a few germs the certainty of arriving at maturity. In order +to render the ideas of germ-fecundity and productiveness more easily +understood, Prof. Mobius makes the following comparison between the +oyster and man: + +According to Wappaus, for every 1,000 men there are 347 births. +According to Bockh, out of every 1,000 men born 554 arrive at maturity, +that is, live to be twenty years or more of age; thus, on an average, +347 children are produced from 554 mature men, or 626 children from +1,000 mature men. Since 1,000 full-grown oysters produce 440,000,000 of +germs, then the germ fecundity of the oyster is to the germ fecundity of +man as 440,000,000 to 6.26, or as 7,028,754 to 1. On the other hand, the +number which arrive at maturity is 579,002 times as great with mankind +as with the oyster; for of 1,000 human embryos brought into the world +554 arrive at maturity, or of 440,000,000 newly born 243,760,000 would +live to grow up, while of 440,000,000 young oysters only 421 ever become +capable of propagating their species. The proportion is then 421 to +243,760,000, or as 1 to 579,002. I am fully persuaded that these figures +represent the number of oysters which arrive at maturity more favorably +than is really the case, since from every thousand of full grown oysters +it is certain that, on an average, more than 440,000,000 young are +produced. + + * * * * * + + + + +RED SKY. + + +The beautiful red sky which has been so frequent of late, morning as +well as evening, has excited much comment. The comment, however, has +consisted more of description, statement of fact, theory, and wonder as +to cause, rather than as to satisfactory explanation. + +Facts in the case which would reveal the secret of this beautiful +display of nature are not complete and numerous enough at present to +establish the cause of this phenomenon on a sure basis; yet enough +facts, it would seem, have been obtained to satisfy the strong mind +capable of bridging over a wide expanse. + +Facts in an argument are like piers to a bridge-the more we have of +them, c. p., the more substantial the structure. When the facts are +_legion_, the structure becomes a causeway, and there is no need of +argument. + +Argument is a bridge--the fewer the facts, the more the necessity for +the bridge; the less the facts, the more argument necessary to connect +the few we have, and the more skill is required to make substantial +connecting links between the few solid piers (facts) that exist. + +One of the queer things in connection with this is, the public have +looked chiefly, if not wholly, to the astronomers for an explanation +of this phenomenon, when it is not their special province to explain +matters in this department of nature. + +The explanation belongs to the department of meteorology, and not to +astronomy. But the fact of having looked to the astronomers shows how +little the world knows of meteorology and how few meteorologists +there are able, ready, and willing to rise and explain in face of the +opposition of the public, who seem to think that the explanation must +necessarily belong to astronomy. Astronomy proper deals with the +position of the earth in space and its relation to the other heavenly +bodies, whether suns, fixed stars, planets, satellites, comets, or other +bodies in the vast space about us. Meteorology deals with the atmosphere +of the globe, in all its forms. Astronomy could be studied in the early +ages; its grand facts were not wholly dependent upon the advanced +condition of the mechanic arts; it could be studied even without the aid +of telescopes, though telescopes have added much to its advancement. +Meteorology, on the contrary, depended on the advancement of the arts +and sciences; they must first be perfected ere we could know much about +this branch of science. To one unfamiliar with the advancement and +perfection of meteorology within the past ten years, this statement +may seem strange, yet it is an undisputable fact that, prior to the +establishment of the daily weather reports, the knowledge on this +subject amounted to very little, and was not even worthy of being +designated a science. Prior to the advent of the weather map the world +was in absolute ignorance of the laws governing the atmosphere. Sure, we +had had large volumes on the laws of storms, but the later revelations +leave them shelved high and dry on the shores and as useless as a wreck +in a similar condition; with the daily weather map before us we have no +need to even open these huge volumes; they are completely circumvented, +and only negative in value--to show how little was known of the subject +without the full and complete facts daily collected and spread before us +on the map published by the Weather Bureau. + +In order to understand the color of our sky, we must understand the +subject which is so immediately connected with it and its creation. + +The earth is a sphere in space; generally speaking, it is composed of +land and water. These are two factors; the heat that it derives from +the sun forms a third factor; the three--land, water, and heat--are +essential to life, at least the higher conditions of life which +culminate in man. The old physical geography taught us this much, but +it was not able to go further and tell us why it was cold or warm +independent of the seasons; it could not explain why it was at times as +warm, and even warmer, half-way to the pole than at the equator; why it +was at times very warm in the extreme northeast while very cold in +the Southern States; cold in the northwest when it was warm in the +northeast, and warm in the northwest when cold all along the upper +Atlantic seaboard; it could not forewarn us of storms. These and a +host of other facts, which the weather map makes as plain as astronomy +demonstrates that Jupiter is a planet, the new revelation, through the +instrumentality of the perfected telegraph system, makes exceedingly +plain to us if we will but seek the easily obtained information. + +The principal revelations of the weather map are the facts in regard to +the areas of high and low barometer, and the influence they exert upon +the climate of the globe. + +These conditions--high and low barometer--move on general lines from the +west towards the east, or towards the rising sun, and around the world +in irregular belts. The centers of low barometer are various distances +apart, from a thousand to two thousand and even more miles apart--call +the average about two thousand miles. + +The clouds are formed from the moisture present by the action of the +sun's heat. The direction of the wind is from the area of high barometer +to that of low. The nearer the winds approach the center of "low" (low +barometer), the more they partake of the lines of the volute curve, or +curve of the sea shell or water in a whirlpool. High barometer is the +atmospheric hill; low barometer is the atmospheric valley. But time at +present will not permit more than these general statements; a close +study of the weather map for a season will reveal the beautiful minor +details. + +To the reader it may seem a long way round, yet in order to fully +understand the nature of the atmosphere which surrounds our globe we +must pay due attention to these newly discovered physical laws. + +The red sky which was so noticeable, in the fall of 1883, the +astronomers have told us was due to "meteoric dust" which was produced +by the volcanic eruption on the island of Java, August 27, 1883. + +This "meteoric dust" they say combined with the atmosphere, followed it +around the earth, and caused the beautiful redness of the sky at morning +and evening. For one, I do not believe dust of any description in the +atmosphere would produce such an effect. + +There is nothing luminous, transparent, or delicate about dust. Dust +would not remain in the atmosphere for months, it would settle in a very +short time, and if thick enough in the atmosphere to obstruct the light +of the sun it would be visible, discernible, to the eye, and manifest +on the face of nature. Years ago, before the age of the weather map, we +might have thought that the atmosphere followed the surface of the earth +like the water on a grindstone, but it does not. As already seen, the +wind is from the area of high barometer to that of low, and there are +many of these "low centers." + +From the best calculation we can make at present, there would be at +least some six centers on an average between the center of the United +States and the island of Java. In addition to this there would also be +a number of belts of "low" centers, which would complicate the thing +threefold at least. At all these different centers the winds would be +blowing from all points of the compass at the same time. Such winds +would not be apt to bring the "meteoric dust" from Java to the United +States, either in an easterly or westerly direction. But, it is said, +"dust" has been gathered. + +How high from the surface of the ground has this _dust_ been +gathered--at what elevation? + +There is undoubtedly a little dust in the air most of the time, but I do +not think that it extends very high. Where it would be the highest and +most perceptible would be on the arid plans of Africa and Asia, when +the _simoom_ is passing, or in the track of a tornado. But from the +multiplicity of these storm centers and the varied winds they would +produce even this dust could not travel from Java to America. + +Again, all clouds, no matter how high or how low, are affected by the +low centers, as the movement of clouds prove, and travel from the "high" +to the "low," from and to all points of the compass. High authority +gives the heights of the clouds as follows: lower clouds, 16,000 feet; +upper clouds, 23,000 feet. + +As all clouds, from the highest to the lowest, are affected by the +centers as above referred to, it follows that if this "meteoric dust" +follows the earth around, as it would have to do in order to make good +this theory, it would have to travel suspended in the atmosphere above +the upper clouds, or at a height of more than 23,000 feet, or at an +elevation of over four miles! + +Now, is it reasonable to believe that dust, however fine, will remain in +the atmosphere at that elevation for over six months? + +As a side argument it is suggested that the smoke of the burning woods, +or few years ago in Michigan, caused as peculiar condition of the +atmosphere. This extensive fire was on a day when the area of low +barometer was on a high line of latitude and passing to the eastward. +This naturally took the smoke, which is far lighter than dust, along +with it. It mingled with the muggy condition of an extensive "low," and +produced a yellowness of the atmosphere. This however was of only a few +hours' duration, and was only visible in favorable localities. + +Here again we see the advantage of the weather maps; but for this map we +would never have been able to have satisfactorily explained the peculiar +phenomenon produced by the great Michigan fire. + +If the delicate redness of the sky is not caused by dust, what is it +caused by? + +But for the weather map, I think we should still be in the dark in +regard to it. + +In the first place, this redness is nothing new, only the conditions +are more favorable sometimes than at others. It has always existed and +always will exist, independent of earthquakes, volcanoes, etc. Nature +is ever changing; the movements of the atmosphere more resemble the +kaleidoscope than any thing else. + +The summer and fall of 1883, the movements of "high" (high barometer) +over the United States were quite central and extensive, causing this +peculiar phenomenon over a wide extent of territory. + +We have no information of the condition of the barometer over the other +part of the world; we speak move particularly of the United States; yet +if certain conditions produce certain effects here, it is quite safe to +say that the same effects are produced by the same cause elsewhere. + +As now well established by the map, the surface wind is from the area +of high barometer to that of low--from the atmospheric hill to the +atmospheric valley. + +The tendency of this is to free "high" of all clouds and moisture; but +then it is impossible to free "high" entirely of moisture; a little +will remain, and it is just this little, which is highly rarefied, that +produces the result. We look around us and above, we see little or no +evidence of evaporation, yet it is the while going on. When the sun is +immediately below the horizon, where it will shine horizontally through +the mass of light, suspended moisture, the delicate presence of vapor +heretofore unnoticed is revealed. The action of the sun's rays is the +same as when illuminating a well formed cloud--it is an embodiment +of the same principle, but the material is much more expanded. The +particles of suspended moisture are very fine, few and far between, +therefore the effect of the light upon it is more diffused and +transparent. It is much like looking through a piece of window glass +flatwise and endwise; flatwise we do not perceive any color; endwise, +from seeing through a greater mass, the glass has a very perceptible +green color. + +We see the same idea also in the rising and setting sun and moon. On +a clear, cloudless night, when nothing seems to interfere with the +brightness of the stars, we cannot, by looking upward, perceive any +moisture present in the atmosphere; but if we cast our eyes to the +horizon, whereby we see through the mass of atmosphere endwise, as it +were, and note the appearance of the stars there, or the rising or +setting moon, we will see that the atmosphere there gives a redness +to the rising body, which it does not have when it has ascended to +mid-heaven. On a clear night, which is caused by the presence of the +area of high barometer, the moon when in mid-heaven is of a clear, +silver-white, and it is the same moon that at the horizon was a deep +red. The color of the moon has not changed; it is simply the medium +through which it is seen that produces the difference in color. + +Occasionally, on a clear, bright ("high") night, when the moon is full, +prior to rising, when just below the horizon, it will so illuminate this +lower strata of atmosphere as to appear like a great fire; the moon +rises red, but its deep color gradually fades as it rises, and when well +up in the heavens we perceive that this deep coloring was an illusion +and merely the influence of its surroundings. I never, though, knew of +any one to attempt to account for this by "meteoric dust;" and yet it is +an embodiment of the same principle. Place the sun where the moon is, +and from its far superior abundance of light we have a much grander +display. + +Under no other conditions or relations of the sun and earth is it +possible to have this phenomenon of the delicate red sky but when a +positive area of high barometer is passing and extends over us. In +order to produce this effect we must have the clear atmosphere of high +barometer, when there is a minimum of moisture present. The action of +the sun's rays upon this extensive area of slightly moist rarefied +air is unconfined by clouds, and reaches far and wide, and produces +a delicacy of color which from no other source or condition can be +realized. + +ISAAC P. NOYES. + +Washington, D. C., 1884. + + * * * * * + + + + +A THEORY OF COMETARY PHENOMENA. + + +_To the, Editor of the Scientific American_: + +The following subject, substantially, was written more than a year ago +with a view to its publication. It was not, however, until January of +the present year that I sent a brief communication to the _Brooklyn +Eagle_, which was published Feb. 3, giving my views in relation to +cometary phenomena. With this I might remain satisfied, were it not +that the interesting paper by G. D. Hiscox, published in the SCIENTIFIC +AMERICAN SUPPLEMENT, Feb. 16, impressed me with the idea that the theory +I advanced might assist in explaining others, if brought to the notice +of those interested through the columns of your valuable journal. + +The theory that I advance to account for the several phenomena relating +to comets' tails is, that comets are non-luminous, transparent bodies; +that they transmit the light of the sun; that the transmitted light +reflected by the particles of matter in space constitutes the tails of +comets. "Like causes produce like effects." By contraries, then, like +effects must be produced by similar causes; for, if an effect produced +by a cause which is known is similar to an effect produced by a cause +which is not known, the cause which is known must be similar to the +cause which is not known. This is true or not. + +I submit the following experiments to substantiate the theory advanced. + +Partially fill a vial or a tumbler with water, hold it by the rim, +and move it around a lighted candle placed upon a table. A shadow +surrounding the transmitted light will be cast upon the table. As the +tumbler approaches the light, the shadow follows the tumbler, and when +receding the tumbler follows the shadow; and as the tumbler is moved +around the light, the shadow will swing round from one side to the +other. If the tumbler be held so that a puff of smoke can be blown +into the transmitted rays, the particles of smoke will reflect the +transmitted light, and will illustrate my idea of what constitutes a +comet's tail. A dark band may be observed in this stream of light, as +also in the light cast upon the table. + +In these experiments, we see the effects produced by a cause which is +known; the effects are similar to those observed in the tails of comets, +the cause of which we do not know; but is it not reasonable to assume +that the cause is similar? + +Assuming now that comets are transparent, can any other phenomena +peculiar to comets be accounted for upon this hypothesis? Next to +the tail itself, the curve is the most noticeable feature, and if we +consider the extraordinary length of these appendages, the astounding +velocity at which comets move in their orbits, and the time that would +elapse before a ray of light, emitted from the nucleus, would reach the +end of the tail, perhaps the curve--which, if I am not deceived in my +observations, always dips toward its orbit--can be accounted for. If a +comet moved in a direct line toward the center of the sun, there would +be no curve to the tail. But taking Donati's comet of 1858 as an +example, the tail of which was said to be about 200,000,000 miles long, +a ray of light traveling at the rate of 192,000 miles per second would +be about twenty minutes in going from the nucleus to the end of the +tail. + +But during that time the comet would move in its orbit, say, 50,000 +miles, and as light moves in a straight line, and other rays are +constantly emerging from the nucleus as it moves along in its course, +the result is that the tail has a curved appearance. + +I have no data at hand regarding this comet, but what I have said will +serve to illustrate my ideas. Again, referring to this comet, I remember +to have read the statement of an astronomer that, after passing round +the sun, a new tail was formed opposite the original one. Now, it seems +to me that that is just what would happen, for in moving round the sun +the comet would travel say 3,000,000 miles; the greater portion of the +tail then, would extend millions of miles upon one side of the sun, +while from the nucleus upon the opposite side of the sun a new tail +would appear to be formed. + +Upon this hypothesis, the extraordinary length of their tails and the +fact that stars are visible through the densest portion of them is +explained; as also the fact that they so rapidly disappear from view +when moving from the sun, the light received by them from the sun +being in proportion to their distance from it, and but little of that +reflected. + +JOHN M. HUGHES. + +Brooklyn, N. Y. + + * * * * * + +[FOR THE SCIENTIFIC AMERICAN.] + + + + +ON COMETS. + + +When we see a comet approaching the sun with its tail following in the +orbit of the nucleus, we have no great difficulty in believing the +common theory that a comet consists of nucleus attracted toward the sun, +while the tail is repelled; and that we see the whole of it. But as it +approaches the sun, difficulties arise that make us doubt whether the +theory be true. + +Let us suppose a comet with a tail 50,000,000 miles in length, and that +it will require two days to pass round the sun. Now the tail, being +always in a line drawn through the center of the sun and center of the +nucleus, will, when it reaches the long axis of the elliptical orbit, +stand perpendicularly to the orbit of the nucleus. That is, the +extremity of the tail farthest from the sun, in addition to its onward +motion, has acquired a lateral motion that has lifted it 50,000,000 +miles in the first day of its perihelion. The velocity of the extremity +has been vastly accelerated over that of the nucleus, and it has +moreover a sheer lift above the orbit of the nucleus. Now this lift is +in opposition to gravity; neither is it in consequence of any previous +momentum, for its velocity is accelerated and its previous momentum +would be a hindrance; nor is the lift in consequence of any repelling +force from the sun, for such force would be diminished in proportion to +the square of the distance, and the far end would be acted on less than +the nucleus end of the tail, whereas the velocity of the former is +increased a hundred fold over that of the latter. A polar force in the +comet would merely draw the comet into the sun. We therefore find no +force adequate for such a lift, but on the contrary all the forces are +opposed to it. + +But if the first day of the perihelion overwhelms us with difficulty, +the second day will prove disastrous to the common theory. For the +extremity of the tail farthest from the sun will be required to pass +with lateral motion from its perpendicular 100,000,000 miles, so that it +may be in advance of the nucleus and again rest on its orbit. This orbit +is an impassable line, and therefore instantly arrests the prodigious +lateral velocity of the tail. That impassable orbital line is to it +as solid and inflexible as a wall of adamant. The motion so instantly +arrested would be disastrous to any tail, whether composed of gas, +meteorites, or electricity, whatever that may be. + +Having shown that the common theory of comets is filled with insuperable +difficulties, I will again call attention to a theory proposed about +eighteen months ago in the SCIENTIFIC AMERICAN. + +According to this theory, a comet consists of a nucleus and an +atmosphere, for the most part invisible, surrounding it on all sides to +an extent at least equal to the length of the tail. The rays of the sun +in passing through or near the nucleus are so modified as to become +visible in their further progress through the cometic atmosphere, while +all the rest remain invisible. What we call the tail is merely a radius +of the cometic atmosphere made visible, and as the comet moves through +space, only different portions of the atmosphere come in sight, in +obedience to the ordinary laws of light. There is no difficulty in +accounting for the rise and fall of the tail at perihelion, nor for the +tail preceding the nucleus afterward. + +The spherical theory accounts easily for the different forms of tail +seen in different comets. The sword shaped tails, at variance with the +common theory, can be accounted for by supposing a slight difference in +density or material in the cometic atmosphere, which will deflect the +light as seen. The comet of 1823, which cannot be explained on the +common theory, is very easily explained on the spherical. That comet +showed two tails, apparently of equal length, which moved opposite to +each other, and perpendicularly to the orbit of the nucleus, and showing +no signs of repulsive force from the sun. On the spherical theory it is +only necessary to suppose such an arrangement of the nucleus as would +reflect the rays of the sun laterally; a slight modification of the +nucleus would give not only two but any number of tails pointing in +different directions. + +It may be objected to the spherical theory that a tail 50,000,000 miles +long would call for a sphere 100,000,000 miles in diameter, and that +would be too vast for our solar system. But it is claimed for this +sphere that it consists of the same material as the so-called tail, and +that it has the same capability of moving among planets without manifest +disturbance to either. + +The sphere at the perihelion would envelop the sun, and as a noticeable +reduction is sometimes found in its so-called tail, the cometic +atmosphere may impart to the sun at that time whatever is necessary to +its use. + +That there is something in common between the sun's corona and cometary +matter was shown by the last solar eclipse observed in South Pacific +Ocean, where the spectrum of sun's corona was found to be the same as +that of a comet's tail. Are we to attribute in any degree the different +appearances of the sun's corona to the presence or absence of a comet +at its perihelion? At the eclipse of the sun seen in Upper Egypt two or +three years ago, a comet was seen close to the sun, but I have seen no +account of the appearance of the corona at that time. + +FURMAN LEAMING, M.D. + +Romney, Tippecanoe Co. Indiana. + + * * * * * + + + + +FORMS OF IVY. + + +It is scarcely possible for us to bee too emphatic in our praises of the +most distinct forms of ivy, since but few other hardy climbing plants +ever give to us a tithe of their freshness and variety. A good long +stretch of wall covered with a selection of the best green-leaved kind +is always interesting, and never more so than during the winter months, +especially if at intervals the golden Japanese jasmine is planted among +them or a few plants of pyracantha or of Simmon's cotoneaster for the +sake of their coral fruitage. The large-leaved golden ivy is also very +effective here and there along a sunny wall, especially if contrasted +with the small-leaved kind--atropurpurea--which has dark purple or +bronzy foliage at this season. Of the large-leaved kinds, one of the +most distinct is canariensis, or large-leaved Irish ivy, and Raegner's +variety, with leathery, heart-shaped foliage, is also handsome. The +birdsfoot ivy (pedata) is curious, as it clings to the stones like +delicate leaf embroidery, and for shining green leafage but few equal +to the one called lucida. The two other kinds sketched are hastata and +digitata, both free growing and distinct sorts. + +[Illustration: VARIOUS FORMS OF IVY. Heart-leaved Ivy (Hedera +Raegenerana). Glossy Ivy (H. lucida). Arrow-leaved Ivy (H. hastata).] + +_Ivy Leaves_.--Common ivy is tolerably plentiful nearly everywhere, but +it is not common to find a good distinct series of its many varieties +even in the best gardens. Of all the different forms of ivy, I think +the large-leaved golden one of the best; certainly the best of the +variegated kinds. Raegner's variety is also very bold, its great glossy, +heart-shaped leaves most effective. Algeriensis is another fine-leaved +kind, the form dentata producing foliage even still larger when well +grown. For making low evergreen edgings on the turf, for carpeting +banks, the covering of bare walls and the old tree stumps, we have no +other evergreen shrub so fresh and variable, or so easily cultivated as +are these forms of the ivy green. Perhaps one reason why the finer kinds +of ivy are comparatively uncommon is the fact that a strong prejudice +exists against ivy in many minds. It is an erroneous notion that ivy +injures buildings against the walls of which it is planted; it never +injures a good wall, nor a sound house, but on the contrary, hides and +softens the stony bareness of the one and adds beauty and freshness to +the other.--_The Garden_. + +[Illustration: VARIOUS FORMS OF IVY. Finger-leaved Ivy (H. Itata). Irish +Ivy (H. canariensis). Rira's foot Ivy (H. pedata).] + + * * * * * + + + + +PROPAGATING ROSES. + + +In an article on this subject an English horticultural journal describes +the method pursued by a London florist. After stating that out of a case +containing 310 cuttings only five failed to root, the article proceeds: +The case or box is made of common rough deal boards. It is five feet +six inches long and one foot in depth. Within half an inch of the top a +groove is cut inside the box, into which the glass is slid, after the +manner of a sliding box lid. In the end of the third week in July the +box was placed in the kitchen garden under the shadow of a high north +wall; it was then about half filled with good turfy loam, to which had +been added a little leaf mould and a good sprinkling of sharp sand. The +soil was then pressed down very firmly (the box being nearly half full +when pressed), and then thoroughly well soaked with rain water, and +allowed to stay uncovered until the next day. The next day good stout +cuttings were taken of all the roses, both tea and hybrid perpetual, +which it was desired to add to the stock. They were then inserted +closely and firmly in the soil, just over the bottom leaf, the glasses +were slipped on and puttied down; the grooves in which the glass slid, +and even the joints in the glass, being filled with putty, so as to +exclude the air. The whole thing completed, nothing more remained to be +done but to leave the box in its cool, shady nook for five or six weeks, +when the growing points of the free starting kinds gave notice that the +glasses might be removed, a bit at a time, with safety. Nothing could be +more simple, or demand less skill, and the operation may be carried out +successfully by an amateur at any time during the season, when good firm +cuttings can be got, and when six weeks' tolerably fine weather may be +counted on. The success of the whole thing depends on having the glasses +fixed so that they may not be removed until the cuttings are rooted, and +in placing the boxes in a shady place. So treated, carnations and many +of our shrubs and herbaceous perennials may be propagated by unskilled +persons with certainty, and without much trouble. + + * * * * * + + + + +A FEW OF THE BEST INULAS. + + +Of the fifty-six species of Inula described in scientific works, +probably not more than thirty are at present in cultivation in +this country, and those are chiefly confined to botanic gardens, +notwithstanding the fact that many of them are useful garden plants. +They are principally distributed throughout Southern Europe, although we +find them extending to Siberia and the Himalayas; indeed, it is to the +Himalayas we are indebted for the kinds that are most ornamental. Some +of the low-growing species are extremely useful for the rockery, such +as I. montana (the Mountain Inula), a fine dwarf plant with woolly +lanceolate leaves and dense heads of orange-colored flowers, resembling +in habit and general appearance some of the creeping Hieraciums. It is a +handsome and desirable plant for the decoration of old walls and similar +places, where it can be a little sheltered from rain and drip. Another +very useful species for this purpose is I. rhizocephaloides, found +plentifully in the Himalayas. It is one of the prettiest Alpine +composites we have. It seldom attains more than from one inch to two +inches in height, forming a dense rosette of short, hairy, oval leaves, +in the center of which the bright purple involucres, in the form of a +ball, are extremely interesting. It is easily cultivated, requiring, +however, a rather snug nook, where it will not be allowed to become too +dry. It is best propagated from seed. Then there is the woolly Inula (I. +candida), a pretty plant with small oval leaves, covered with a thick, +silky down, and much in the way of the white-leaved I. limonifolia, both +of which are very effective when grown in masses, which should always +be low down near the front of a rockery, or as an edging for a mixed +border. The glandular-leaved Inula (I. glandulosa), of which a good +representation is here given, is a beautiful hardy perennial. It is a +native of Georgia and the Caucasian Alps, near the Caspian Sea. It is +a rather robust-growing species, with large, bright, orange-yellow +flowers, varying from three to five inches in diameter, the narrow and +very straggly ray florets contrasting nicely with the rather prominent +disk. The leaves, although quite entire, seem notched, owing to large +black glands which form on their margins. They are lanceolate, and clasp +the stem. The plant is very variable, both as regards robustness and +size of flowers, and this may in a measure account for the confusion +existing between it and I. Oculus-Christi. + +The soil most suitable for the full development of I. glandulosa is a +strong, clayey, retentive loam; it does not thrive well in the light +shallow soils in the neighborhood of London, except in shady positions. +I. Hookeri is a free-flowering perennial, with pointed lanceolate +leaves, of a delicate texture, bright green, and very finely toothed. +The flowers, which are sweet-scented, are not so large as those of I. +glandulosa, and are produced singly, the ray florets being, however, +much more numerous, rarely numbering less than thirty. It is found in +abundance in rocky places in Sikkim, where it replaces the nearly allied +I. grandiflora, a dwarfer species, with much shorter, shining leaves; +both are very desirable plants either for rockery or flower border work. +The Elecampane (I. Helenium) is an imposing, robust-growing species, +having large, broad leaves a foot or more in length. It grows from four +feet to five feet in height, and its thick, shaggy branches are crowned +with large yellow flowers. For isolating in woods this plant, is very +useful, and with the exception of Telekia cordifolia, it would be hard +to find a rival to it. It is, I believe, pretty extensively used for +planting in shrubberies, but unless they are thin and open it is seldom +seen to advantage. It is found wild or naturalized in some parts of +England. It flowers in June and July, and even into August when the +season has been favorable. + +[Illustration: INULA GLANDULOSA (_flowers deep yellow_.)] + +For naturalizing in woods the following will be found useful, _viz_., I. +salicina, I. Oculus-Christi, I. squarrosa, I. britannica, and many more, +the true beauty of which can only be realized in this way. With the +exception of I. rhizocepbaloides, they are all propagated by division +with the greatest ease, or by seed, which is best sown as soon as it is +ripe.--_D.K., The Garden_. + + * * * * * + + + + +FRUIT GROWING. + +By P.H. FOSTER. + + +In the first place, if you contemplate appropriating a portion of your +land for the raising of fruits, you should have the orchard so situated +that no large animals can run at large on the grounds. Prepare your soil +in the most thorough manner; underdrain, if necessary, to carry off +surplus water; dig deep, large holes; fill in the bottom with debris; +in the very bottom put a few leaves, clam and oyster shells, etc., then +sods; above and below the roots put a good garden or field soil; do not +give the trees fresh manure at the time of setting, but the following +fall manure highly with any kind on top of the ground; dig it in the +following spring; keep the soil frequently worked during the summer, +and, if convenient, mulch with hay, straw, or leaves. + +Now you are on the road to progress, provided you have made no mistake +in the selection of your trees. The purposes for which you intend your +fruit is highly important. You should well consider at the outset if +for family or market use. This is a business which requires a long look +ahead, for it is said, "He who plants pears looks ahead for his heirs." + +Caution should be used in procuring your stock; little should be planted +that is not fairly tested on the Island, purchased of parties who can be +fully relied upon to give you what you want. Do not buy your stock of +parties who carry labels in their pockets to make to order what you want +out of the same bundle of trees. + +Now, having your trees set out in a proper manner, of such varieties +as you desire, the next important step is to bring the trees into +usefulness. My plan is to use bone--fine bone--very freely about every +three years. Another important matter is that of trimming. "Fire +purifies," and the knife regulates the grand balance or equilibrium +between roots and tops. In most cases the top outgrows the roots, the +consequence of which is an ultimate weakness of the tree. It is thrown +into excessive fruiting, disease, and premature decay. To avoid this +result, use the knife when required. Thin out the inside branches when +small, and if the tree does not make a satisfactory growth, cut back +half way to the ground. + +We will suppose that you have got your trees growing nicely, and they +have begun to bear fruit. There are other important steps to be taken, +which will be of little cost to you. Provide a wind-break for the +orchard. Evergreens answer the purpose, being a protection against the +wind. Having this matter attended to, there are other enemies with which +we must contend. I refer to the apple and peach tree borers. The former +will live in the tree for three years, if unmolested; the latter, one +year only. They are very easily destroyed by looking over the trees and +taking them out with a knife; or maybe prevented from touching the trees +by wrapping a piece of felt paper, 8 inches wide, around the tree near +the ground, the bottom being covered with dirt and the top tied tightly +above. The pear is not generally disturbed by these insects--only the +apple, peach, and quince. We have another insect very destructive to the +plum, peach, cherry, and apple--the _curcutio_, or plum weavel. This +season for the first time in twenty years we have gathered a small +crop of that very desirable plum, the Purple Favorite. We simply threw +air-slaked lime over the trees nearly every morning for from four to six +weeks, from the time the tree was out of bloom. Peach trees should be +treated in the same manner. Another method of fighting this insect is to +spread a sheet under the tree, and with a blow jar off the little Turk +and secure him on the sheet. But I consider the lime procedure the less +trouble and more effective. The tent caterpillar, which is easily seen, +should be destroyed at once. We have yet another insect to contend with +which infests the apple and pear, commonly called the Coddling Moth, +and the larva, the apple-worm (_Garpocapsa pomonella_). The loss by the +ravaaes of this insect alone to the fruit growers of the United States +fan hardly be estimated, as in many cases the whole crop is rendered +worthless. Such a vast destruction of two of the most valuable fruits +the world produces should stimulate scientists in this age of progress +to discover an effectual remedy against such a gigantic evil. + +I have never yet discovered nor tried an effectual remedy against this +insect. The nearest I have approached his extermination is in the +following manner: After it has entered the fruit and accomplished its +damage, the time arrives when it has to leave the fruit and hide itself +in a quiet, secure position to undergo the transition from the larva to +the pupa state, which requires, in the early part of the season, eight +or ten days; after this time the miller is hatched and is again ready to +besiege the fruit with its sting. The insect, being two-brooded in this +climate at least, if not disturbed, has an aggregating force to do +mischief the second time. The progeny for the succeeding year have alone +to depend on the security of this second generation of larvae. As they +may often be found in bark of apple trees during winter, my plan of +destruction is, about the first of July to take woolen rags long enough +to wrap around the trees, and say four inches wide. Each week I look +over the trees, and destroy the worms secreted under the rags and +wherever I find them until the fruit is off the trees. I have all the +green fruit, of every kind, carefully picked up as soon as it falls, +thereby destroying many of the curculio as well as the apple-worms. + +One word upon the grape--the insect part of the question. The +_Phylloxera vastatrix_, or grape-vine louse, is already at work on Long +Island. It is found very difficult to raise many of our fine, new grapes +with us in consequence of the depredations of this very minute insect, +it being almost too small to be seen by the naked eye. There has lately +been discovered a remedy which is entirely chemical and as yet but +little disseminated. Very soon, no doubt, a discovery will be made that +will stay the progress of this destructive enemy. + +We should plant aplenty of cherry and small fruit trees to yield feed +for birds. In return they will assist us in our efforts to preserve a +bountiful supply of this health producing element. + + * * * * * + + + + +COARSE FOOD FOR PIGS. + + +A recent subscriber wants advice how to feed pigs of 25 to 35 pounds +weight, that are to be kept over winter and fitted for sale at about six +months old--whether coarse food will not help them as much in winter as +in summer. How roots and pumpkins will answer in lieu of grass, and what +can be fed when this green food is gone? He has had poor success in +growing young pigs on corn alone. He has a reasonably warm pen for +winter. + +The question of food is constantly recurring, and this is one of the +best evidences of the advancement of the country in the feeder's +art. When people are making no inquiry as to improved methods in any +direction, no progress can be made. There has been more progress made +in the philosophy of feeding during the last thirty years than in the +century and a half previous. + +In pig feeding in the dairy districts, young pigs generally grow up in +a very healthy condition, owing to the refuse milk of the dairy, which +furnishes the principal food of young pigs. Skim-milk contains all the +elements for growing the muscles and bones of young pigs. This gave them +a good, rangy frame, and, when desired, could be fed into 400 or 500 +pounds weight. But the fault attending this feeding was, that it was too +scanty to produce such rapid growth as is desired. It took too long to +develop them for the best profit. It had not then been discovered by the +farmer that it costs less to put the first hundred pounds on the pig +than the second, and less for the second than the third, etc.; that it +was much cheaper to produce 200 pounds of pork in six months than in +nine and twelve months. When it became evident that profit required more +rapid feeding, then they began to ply them continually with the most +concentrated food--corn meal or clear corn. If this was fed in summer, +on pasture, no harm was observed, for the grass gave bulk in the +stomach, and the pigs were were healthy and made good progress. But if +the young pigs were fed in pen in winter upon corn meal or clear corn, +the result was quite different; this concentrated food produced feverish +symptoms, and the pigs would lose their appetite for a few days, +drinking only water, which, after a while, would relieve the stomach, +and the pigs would eat vigorously again. Now, had they been fed a few +quarts of turnips, carrots, beets, or pumpkins, to give bulk to the +stomach, and separate the concentrated food, no harm would have come. +This gives the gastric juice a free circulation through the contents of +the stomach, the food is properly digested and applied to the needs of +the body instead of causing fever by remaining in the stomach.--_Live +Stock Journal_. + + * * * * * + + + + +METE KINGI. + + +Our engraving is a portrait of a familiar character in New Zealand, +chief Mete Kingi, who recently died at the age of one hundred years. +He was a fine specimen of the Maori race, the native New Zealanders, a +branch of the Malayo-Polynesian family. The New Zealanders surpassed +all other people in the art of tattooing, to which their chiefs gave +especial attention. Mete Kingi, as our picture shows, was no exception. +Tattooing on the face they termed _moko_. The men tattoo their faces, +hips, and thighs; the women their upper lips; for this purpose charcoal +made from kauri gum is chiefly used. It has the blue color when pricked +into the skin, growing lighter in shade in the course of years. The +subject of our illustration embraced Christianity, and was much +respected. Our engraving is from the _Illustrated Australian News_. + +[Illustration: THE LATE MAORI CHIEF METE KINGI.] + + * * * * * + + + + +LAKE TAHOE. + + +Some very interesting information by Prof. John Le Conte, is given in +the _Overland Monthly_, being the result of some physical observations +made by the author at Lake Tahoe, in 1873. Lake Tahoe, also called Lake +Bigler, is situated at an altitude of 6,247 feet in the Sierra Nevada +Mountains, partly in California, partly in Nevada. The lake has a length +of 22 and a width of 12 miles. As regards its origin, the author regards +it as a "plication hollow," or a trough produced by the formation of two +mountain ridges, afterward modified by glacial agency. The depth of the +lake is remarkable; the observations taken at ten stations along the +length of the lake gave the following depths in feet: 900, 1,385, 1,495, +1,500, 1,506, 1,540, 1,504, 1,600, 1,640, 1645. This depth exceeds that +of the Swiss lakes proper--Lake Geneva, for example, has a maximum depth +of 1,096 feet--but is considerably less than that of Lakes Maggiore and +Como, on the Italian side of the Alps. A series of observations of the +temperature of the water were taken between the 11th and 18th of August. +The average corrected results are as follows: + + Depth in feet. Temp. (C.) + 0(surface).................................19.4 + 50..........................................17.2 + 100..........................................12.8 + 150..........................................10.0 + 200.......................................... 8.9 + 250.......................................... 8.3 + 300.......................................... 7.8 + 330 (bottom)................................. 7.5 + 400.......................................... 7.2 + 480 (bottom)................................. 6.9 + 500.......................................... 6.7 + 600.......................................... 6.1 + 772 (bottom)................................. 5.0 + 1506 (bottom)..............,.................. 4.0 + +The temperature, therefore, diminishes with increasing depth to about +700 or 800 feet, and below this remains sensibly the same down to 1,506 +feet; or in other words, a constant temperature of 4 deg. C. prevails at all +depths below about. 820 feet. This is in accordance with the theory, the +temperature named being that of the maximum density of water, and it +confirms the recent observations of Prof. Forel in Switzerland; he +found, for example, that a constant temperature of 4 deg. C. was reached in +Lake Zurich at a depth of nearly 400 feet, the lake being then covered +with 4 inches of ice. The explanation of the observed fact that Lake +Tahoe does not entirely freeze over even in severe winters is found in +the extreme depth; and the fact that the bodies of drowned persons do +not rise to the surface after the lapse of the usual time is explained +by the low temperature prevailing near the bottom, which does not allow +the necessary decomposition to go forward so as to produce the ordinary +result. + +The water of Lake Tahoe is remarkable both for its transparency and +beauty of color. A series of observations made at the close of August or +beginning of September showed that a horizontally adjusted dinner plate +of about 91/2 inches diameter was visible at noon at a depth of 108 feet. +The maximum depth of the limit of visibility as found by Prof. Forel, in +Lake Geneva, was 56 feet. He showed, moreover, that this limit is much +greater in. winter than in summer, as explained in part by the greater +absence of suspended matter and in part by the fact that increase of +temperature increases the absorbing power of water for light. The +maximum depth of visibility in the Atlantic Ocean, as found by Count +de Pourtales, was 162 feet, and Prof. Le Conte states his belief that +winter observations in Lake Tahoe would place the limit at even a +greater depth than this. The author gives a detailed and interesting +discussion in regard to the blue color of lake waters, reviewing in full +the results of previous writers on the subject, and concludes that while +pure water unquestionably absorbs a larger part of the red end of the +spectrum, and hence appears blue by transmitted light, the color seen by +diffuse reflection is mainly due to the selective reflection from the +fine particles suspended in it. + +The last subject discussed by the author is that of the rhythmical +variations of level, or "seiches," of deep lakes; he applies the usual +formula to Lake Tahoe, and calculates from it the length of a complete +longitudinal and of a transverse "seiche;" these are found to be +eighteen or nineteen minutes in the first case and thirteen minutes in +the second. + + * * * * * + +A catalogue, containing brief notices of many important scientific +papers heretofore published in the SUPPLEMENT, may be had gratis at this +office. + + * * * * * + + + + +THE SCIENTIFIC AMERICAN SUPPLEMENT. + +PUBLISHED WEEKLY. + +TERMS OF SUBSCRIPTION, $5 A YEAR. + + +Sent by mail, postage prepaid, to subscribers in any part of the United +States or Canada. 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Vol. XVII, No. 433. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + + * * * * * + +TABLE OF CONTENTS. + +I. CHEMISTRY, METALLURGY, ETC.--New Analogy between + Solids, Liquids, and Gases. + + Hydrogen Amalgam. + + Treatment of Ores by Electrolysis.--By M. KILIANI. + +II. ENGINEERING, AND MECHANICS.--Electric Railway at Vienna.--With + engraving. + + Instruction in Mechanical Engineering.--Technical and trade + education.--A course of study sketched out.--By Prof. R.H. + THURSTON. + + Improved Double Boiler.--3 figures. + + The Gardner Machine Gun.--With three engravings showing the + single barrel, two barrel, and five barrel guns. + + Climbing Tricycles. + + Submarine Explorations.--Voyage of the Talisman.--The Thibaudier + sounding apparatus.--With map, diagrams, and engravings. + + Jamieson's Cable Grapnel.--With engraving. + + A Threaded Set Collar. + +III. TECHNOLOGY.--Wretched Boiler Making. + + Pneumatic Malting.--With full description of the most improved + methods and apparatus.--Numerous figures. + + Reducing and Enlarging Plaster Casts. + + Stripping the Film from Gelatine Negatives. + +IV. ELECTRICITY.--Non-sparking Key. + + New Instruments for Measuring Electric Currents and Electromotive + Force.--By MESSRS. K.E. CROMPTON and GISBERT + KAPP.--Paper read before the Society of Telegraph Engineers.--With + several engravings. + + When Does the Electric Shock Become Fatal? + +V. ART AND ARCHAEOLOGY.--Robert Cauer's Statute of Lorelei.--With + engraving. + + The Pyramids of Meroe.--With engraving. + +VI. ASTRONOMY AND METEOROLOGY.--The Red Sky.--Cause of + the same explained by the Department of Meteorology. + + A Theory of Cometary Phenomena. + + On Comets.--By FURMAN LEAMING, M.D. + +VII. NATURAL HISTORY.--The Prolificness of the Oyster. + + Coarse Food for Pigs. + +VIII. BOTANY, HORTICULTURE, ETC.--Forms of Ivy.--With + several engravings. + + Propagating Roses. + + A Few of the Best Inulas.--With engraving. + + Fruit Growing.--By P.H. FOSTER. + +IX. MEDICINE, HYGIENE, ETC.--A People without Consumption, + and Some Account of Their Country, the Cumberland Tableland. + --By E.M. WIGHT. + + The Treatment of Habitual Constipation. + +X. MISCELLANEOUS.--The French Scientific Station at Cape Horn. + +XI. BIOGRAPHY.--The Late Maori Chief, Mete Kingi.--With portrait. + + * * * * * + + + + +THE FRENCH SCIENTIFIC STATION AT CAPE HORN. + + +In 1875 Lieutenant Weyprecht of the Austrian navy called the attention +of scientific men to the desirability of having an organized and +continual system of hourly meteorological and magnetic observations +around the poles. In 1879 the first conference of what was termed the +International Polar Congress was held at Hamburg. Delegates from eight +nations were present--Germany, Austria, Denmark, France, Holland, +Norway, Russia, and Sweden. + +The congress then settled upon a programme whose features were: 1. To +establish general principles and fixed laws in regard to the pressure +of the atmosphere, the distribution and variation of temperature, +atmospheric currents, climatic characteristics. 2. To assist the +prediction of the course and occurrence of storms. 3. To assist the +study of the disturbances of the magnetic elements and their relations +to the auroral light and sun spots. 4. To study the distribution of +the magnetic force and its secular and other changes. 5. To study the +distribution of heat and submarine currents in the polar regions. 6. To +obtain certain dimensions in accord with recent methods. Finally, to +collect observations and specimens in the domain of zoology, botany, +geology, etc. + +The representatives of the various nations had several conferences +later, and by the 1st of May, 1881, there were sufficient subscribers to +justify the establishment of eight Arctic stations. + +France entered actively in this work later, and its first expedition was +to Orange Bay and Cape Horn, under the surveillance and direction of +the Academy of Sciences, Paris, and responsible to the Secretary of the +Navy. On the 6th of September, 1882, this scientific corps established +itself in Orange Bay, near Cape Horn, and energetically began its +serious labors, and by October 22 the greater part of their preliminary +preparations was completed, comprising the erection of a magnetic +observatory, an astronomic observatory, a room for the determination of +the carbonic anhydride of the air, another for the sea register, and +a bridge 92 feet long, photographic laboratory, barometer room, and +buildings for the men, food, and appurtenances, together with a +laboratory of natural history. + +In short, in spite of persistent rains and the difficulties of the +situation, from September 8 to October 22 they erected an establishment +of which the different parts, fastened, as it were, to the flank of a +steep hill, covered 450 square meters (4,823 square feet), and rested +upon 200 wooden piles. + +From September 26, 1882, to September 1, 1883, night and day +uninterruptedly, a watch was kept, in which the officers took part, so +that the observations might be regularly made and recorded. Every four +hours a series of direct magnetic and meteorological observations was +made, from hour to hour meteorological notes were taken, the rise and +fall of the sea recorded, and these were frequently multiplied by +observations every quarter of an hour; the longitude and latitude were +exactly determined, a number of additions to the catalogue of the fixed +stars for the southern heavens made, and numerous specimens in natural +history collected. + +The apparatus employed by the expedition for the registration of the +magnetic elements was devised by M. Mascart, by which the variations +of the three elements are inscribed upon a sheet of paper covered with +gelatine bromide, inclination, vertical and horizontal components, with +a certainty which is shown by the 330 diurnal curves brought back from +the Cape. + +The register proper is composed of a clock and a photographic frame +which descends its entire length in twenty-four hours, thus causing the +sensitized paper to pass behind a horizontal window upon which falls the +light reflected by the mirrors of the magnetic instruments. One of those +mirrors is fixed, and gives a line of reference; the other is attached +to the magnetic bar, whose slightest movements it reproduces upon the +sensitized paper. The moments when direct observations were taken were +carefully recorded. The magnetic _pavilion_ was made of wood and copper, +placed at about fifty-three feet from the dwellings or camp, near the +sea, against a wooded hill which shaded it completely; the interior +was covered with felt upon all its sides, in order to avoid as much as +possible the varying temperatures. + +The diurnal amplitude of the declination increased uniformly from the +time of their arrival in September up to December, when it obtained +its maximum of 7'40", then diminished to June, when it is no more than +2'20"; from this it increased up to the day of departure. The maximum +declination takes place toward 1 P.M., the minimum at 8:50 A.M. The +night maxima and minima are not clearly shown except in the southern +winter. + +The mean diurnal curve brings into prominence the constant diminution +of the declination and the much greater importance of the perturbations +during the summer months. These means, combined with the 300 absolute +determinations, give 4' as the annual change of the declination. + +M. Mascart's apparatus proved to be wonderfully useful in recording the +rapid and slight perturbations of the magnet. Comparisons between the +magnetic and atmospheric perturbations gave no result. There was, +however, little stormy weather and no auroral displays. This latter +phenomenon, according to the English missionaries, is rarely observed in +Tierra del Fuego. + +The electrometer used at the Cape was founded upon the principle +developed by Sir William Thomson. The atmospheric electricity is +gathered up by means of a thin thread of water, which flows from a +large brass reservoir furnished with a metallic tube 6.5 feet long. The +reservoir is placed upon glass supports isolated by sulphuric acid, and +is connected to the electrometer by a thread of metal which enters a +glass vessel containing sulphuric acid; into the same vessel enters a +platinum wire coming from the aluminum needle. Only 3,000 observations +were given by the photographic register, due to the fact that the +instruments were not fully protected against constant wet and cold. + +Besides these observations direct observations of the magnetometer were +made, and the absolute determination of the elements of terrestrial +magnetism attempted. + +On the 17th of November, 1882, a severe magnetic disturbance occurred, +lasting from 12 M. until 3 P.M., which in three hours changed the +declination 42'. The same perturbation was felt in Europe, and the +comparison of the observations in the two hemispheres will prove +instructive. + + * * * * * + + + + +THE ELECTRIC RAILWAY AT VIENNA. + + +The total length of this railway, which extended from the Eiskeller in +the Schwimmschul-Allee to the northern entrance of the Rotunda, was +1528.3 meters; the gauge was 1 meter, and 60 per cent. of the length +consisted of tangents, the remaining 40 per cent. being mostly curves +of 250 meters radius. The gradients, three in number, were very small, +averaging about 1:750. + +Two generating dynamos were used, which were coupled in parallel +circuit, but in such a manner that the difference of potential in both +machines remained the same at all times. This was accomplished by the +well known method of coupling introduced by Siemens and Halske, in which +the current of one machine excites the field of the other. + +Although the railroad was not built with a view of obtaining a high +efficiency, an electro-motive force of only 150 volts being used, a +mechanical efficiency of 50 per cent. was nevertheless obtained, both +with one generator and one car with thirty passengers, as well as with +two generators and two cars with sixty passengers; while with two +generators and three cars (two of them having motors) the same result +was shown. + +[Illustration: THE ELECTRIC RAILWAY AT VIENNA.] + +The curves obtained by the apparatus that recorded the current showed +very plainly the action within the machines when the cars were started +or set in motion; at first, the current rose rapidly to a very high +figure, and then declined gradually to a fixed point, which corresponded +to the regular rate of speed. The tractive power, therefore, increases +rapidly to a value far exceeding the frictional resistances, but this +surplus energy serves to increase the velocity, and disappears as soon +as a uniform velocity is reached. + +The average speed, both with one and three cars, was 30 kilometers per +hour.--_Zeitsch. f. Elektrotechnik_. + + * * * * * + + + + +INSTRUCTION IN MECHANICAL ENGINEERING. + +By Professor R. H. THURSTON. + + +The writer has often been asked by correspondents interested in +the matter of technical and trade education to outline a course of +instruction in mechanical engineering, such as would represent his +idea of a tolerably complete system of preparation for entrance into +practice. The synopsis given at the end of this article was prepared +in the spring of 1871, when the writer was on duty at the U.S. Naval +Academy, as Assistant Professor of Natural and Experimental Philosophy, +and, being printed, was submitted to nearly all of the then leading +mechanical engineers of the United States, for criticism, and with a +request that they would suggest such alterations and improvements as +might seem to them best. The result was general approval of the course, +substantially as here written. This outline was soon after proposed as a +basis for the course of instruction adopted at the Stevens Institute of +Technology, at Hoboken, to which institution the writer was at about +that time called. He takes pleasure in accepting a suggestion that its +publication in the SCIENTIFIC AMERICAN would be of some advantage to +many who are interested in the subject. + +The course here sketched, as will be evident on examination, includes +not only the usual preparatory studies pursued in schools of mechanical +engineering, but also advanced courses, such as can only be taught in +special schools, and only there when an unusual amount of time can be +given to the professional branches, or when post graduate courses can be +given supplementary to the general course. The complete course, as here +planned, is not taught in any existing school, so far as the writer is +aware. In his own lecture room the principal subjects, and especially +those of the first part of the work, are presented with tolerable +thoroughness; but many of the less essential portions are necessarily +greatly abridged. As time can be found for the extension of the course, +and as students come forward better prepared for their work, the earlier +part of the subject is more and more completely developed, and the +advanced portions are taken up in greater and greater detail, each year +giving opportunity to advance beyond the limits set during the preceding +year. + +Some parts of this scheme are evidently introductory to advanced courses +of study which are to be taken up by specialists, each one being adapted +to the special instruction of a class of students who, while pursuing +it, do not usually take up the other and parallel courses. Thus, a +course of instruction in Railroad Engineering, a course in Marine +Engineering, or a course of study in the engineering of textile +manufactures, may be arranged to follow the general course, and the +student will enter upon one or another of these advanced courses as his +talents, interests, or personal inclinations may dictate. At the Stevens +Institute of Technology, two such courses--Electrical and Marine +Engineering--are now organized as supplementary of the general course, +and are pursued by all students taking the degree of Mechanical +Engineer. These courses, as there given, however, are not fairly +representative of the idea of the writer, as above expressed, since the +time available in general course is far too limited to permit them to be +developed beyond the elements, or to be made, in the true sense of the +term, advanced professional courses. Such advanced courses as the writer +has proposed must be far more extended, and should occupy the whole +attention of the student for the time. Such courses should be given in +separate departments under the direction of a General Director of the +professional courses, who should be competent to determine the extent of +each, and to prevent the encroachment of the one upon another; but they +should each be under the immediate charge of a specialist capable +of giving instruction in the branch assigned to him, in both the +theoretical and purely scientific, and the practical and constructive +sides of the work. Every such school should be organized in such a +manner that one mind, familiar with the theory and the practice of the +professional branches taught, should be charged with the duty of giving +general direction to the policy of the institution and of directing +the several lines of work confided to specialists in the different +departments. It is only by careful and complete organization in this, as +in every business, that the best work can be done at least expense in +time and capital. + +In this course of instruction in Mechanical Engineering it will be +observed that the writer has incorporated the scheme of a workshop +course. This is done, not at all with the idea that a school of +mechanical engineering is to be regarded as a "trade school," but that +every engineer should have some acquaintance with the tools and the +methods of work upon which the success of his own work is so largely +dependent. If the mechanical engineer can acquire such knowledge in the +more complete course of instruction of the trade school, either before +or after his attendance at the technical school, it will be greatly to +his advantage. The technical school has, however, a distinct field; and +its province is not to be confounded with that of the trade school. +The former is devoted to instruction in the theory and practice of a +profession which calls for service upon the men from the latter--which +makes demand upon a hundred trades--in the prosecution of its designs. +The latter teaches, simply, the practical methods of either of the +trades subsidiary to the several branches of engineering, with only so +much of science as is essential to the intelligent use of the tools and +the successful application of the methods of work of the trade taught. +The distinction between the two departments of education, both of which +are of comparatively modern date, is not always appreciated in the +United States, although always observed in those countries of Europe +in which technical and trade education have been longest pursued as +essential branches of popular instruction. Throughout France and +Germany, every large town has its trade schools, in which the trades +most generally pursued in the place are systematically taught; and every +large city has its technical school, in which the several professions +allied to engineering are studied with special development of those to +which the conditions prevailing at the place give most prominence and +local importance. + +A course of trade instruction, as the writer would organize it, would +consist, first, in the teaching of the apprentice the use of the tools +of his trade, the nature of its materials, and the construction and +operation of the machinery employed in its prosecution. He would next be +taught how to shape the simpler geometrical forms in the materials of +his trade, getting out a straight prism, a cylinder, a pyramid, or a +sphere, of such size and form as may be convenient; getting lines and +planes at right angles, or working to miter; practicing the working of +his "job" to definite size, and to the forms given by drawings, which +drawings should be made by the apprentice himself. When he is able to +do good work of this kind, he should attempt larger work, and the +construction of parts of structures involving exact fitting and special +manipulations. The course, finally, should conclude with exercises in +the construction and erection of complete structures and in the making +of peculiar details, such as are regarded by the average workman +as remarkable "_tours de force_." The trade school usually gives +instruction in the common school branches of education, and especially +in drawing, free-hand and mechanical, carrying them as far as the +successful prosecution of the trade requires. The higher mathematics, +and advanced courses in physics and chemistry, always taught in schools +of engineering, are not taught in the trade school, as a rule; although +introduced into those larger schools of this class in which the aim is +to train managers and proprietors, as well as workmen. This is done in +many European schools. + +As is seen above, the course of instruction in mechanical engineering +includes some trade education. The engineer is dependent upon the +machinist, the founder, the patternmaker, and other workers at the +trades, for the proper construction of the machinery and structures +designed by him. He is himself, in so far as he is an engineer, a +designer of constructions, not a constructor. He often combines, +however, the functions of the engineer, the builder, the manufacturer, +and the dealer, in his own person. No man can carry on, successfully, +any business in which he is not at home in every detail, and in which he +cannot instruct every subordinate, and cannot show every person employed +by him precisely what is wanted, and how the desired result can be best +attained. The engineer must, therefore, learn, as soon and as thoroughly +as possible, enough of the details of every art and trade, subsidiary +to his own department of engineering, to enable him to direct, with +intelligence and confidence, every operation that contributes to the +success of his work. The school of engineering should therefore be so +organized that the young engineer may be taught the elements of every +trade which is likely to find important application in his professional +work. It cannot be expected that time can be given him to make himself +an expert workman, or to acquire the special knowledge of details and +the thousand and one useful devices which are an important part of the +stock in trade of the skilled workman; but he may very quickly learn +enough to facilitate his own work greatly, and to enable him to learn +still more, with rapidity and ease, during his later professional life. +He must also, usually, learn the essential elements and principles of +each of several trades, and must study their relations to his work, and +the limitations of his methods of design and construction which they +always, to a greater or less extent, cause by their own practical or +economical limitations. He will find that his designs, his methods of +construction, and of fitting up and erecting, must always be planned +with an intelligent regard to the exigencies of the shop, as well as to +the aspect of the commercial side of every operation. This extension of +trade education for the engineer into several trades, instead of its +restriction to a single trade, as is the case in the regular trade +school, still further limits the range of his instruction in each. With +unusual talent for manipulation, he may acquire considerable knowledge +of all the subsidiary trades in a wonderfully short space of time, if he +is carefully handled by his instructors, who must evidently be experts, +each in his own trade. Even the average man who goes into such schools, +following his natural bent, may do well in the shop course, under good +arrangements as to time and character of instruction. If a man has not a +natural inclination for the business, and a natural aptitude for it, he +will make a great mistake if he goes into such a school with the hope of +doing creditable work, or of later attaining any desirable position in +the profession. + +The course of instruction, at the Stevens Institute of Technology, +includes instruction in the trades to the extent above indicated. The +original plan, as given below, included such a course of trade education +for the engineer; but it was not at once introduced. The funds +available from an endowment fund crippled by the levying of an enormous +"succession tax" by the United States government and by the cost of +needed apparatus and of unanticipated expenses, in buildings and in +organization, were insufficient to permit the complete organization +of this department. A few tools were gathered together; but skilled +mechanics could not be employed to take up the work of instruction in +the several courses. Little could therefore be done for several years in +this direction. In 1875 the writer organized a "mechanical laboratory," +with the purpose of attaining several very important objects: the +prosecution of scientific research in the various departments of +engineering work; the creation of an organization that should give +students an opportunity to learn the methods of research most usefully +employed in such investigations; the assistance of members of the +profession, and business organizations in the attempt to solve such +questions, involving scientific research, as are continually arising in +the course of business; the employment of students who had done +good work in their college course, when they so desire, in work of +investigation with a view to giving them such knowledge of this peculiar +line of work as should make them capable of directing such operations +elsewhere; and finally, but not least important of all, to secure, by +earning money in commercial work of this kind, the funds needed to carry +on those departments of the course in engineering that had been, up +to that time, less thoroughly organized than seemed desirable. This +"laboratory" was organized in 1875, the funds needed being obtained +by drawing upon loans offered by friends of the movement and by the +"Director." + +It was not until the year 1878, therefore, that it became possible to +attempt the organization of the shop course; and it was then only by the +writer assuming personal responsibility for its expenses that the plan +could be entered upon. As then organized--in the autumn of 1878--a +superintendent of the workshop had general direction of the trade +department of the school. He was instructed to submit to the writer +plans, in detail, for a regular course of shop instruction, and was +given as assistants a skilled mechanic of unusual experience and +ability, whose compensation was paid from the mechanical laboratory +funds, and guaranteed by the writer personally, and another aid whose +services were paid for partly by the Institute and partly as above. The +pay of the superintendent was similarly assured. This scheme had been +barely entered upon when the illness of the writer compelled him to +temporarily give up his work, and the direction of the new organization +fell into other hands, although the department was carried on, as above, +for a year or more after this event occurred. + +The plan did not fall through; the course of instruction was +incorporated into the college course, and its success was finally +assured by the growth of the school and a corresponding growth of its +income, and, especially, by the liberality of President Morton, who met +expenses to the amount of many thousands of dollars by drawing upon his +own bank account. The department was by him completely organized, with +an energetic head, and needed support was given in funds and by a force +of skilled instructors. This school is now in successful operation. +This course now also includes the systematic instruction of students in +experimental work, and the objects sought by the writer in the creation +of a "mechanical laboratory" are thus more fully attained than they +could have possibly been otherwise. It is to be hoped that, at +some future time, when the splendid bequest of Mr. Stevens may be +supplemented by gifts from other equally philanthropic and intelligent +friends of technical education, among the alumni of the school and +others, this germ of a trade school maybe developed into a complete +institution for instruction in the arts and trades of engineering, and +may thus be rendered vastly more useful by meeting the great want, in +this locality, of a real trade school, as well as fill the requirements +of the establishment of which it forms a part, by giving such trade +education as the engineer needs and can get time to acquire. + +The establishment of advanced courses of special instruction in +the principal branches of mechanical engineering may, if properly +"dovetailed" into the organization, be made a means of somewhat +relieving the pressure that must be expected to be felt in the attempt +to carry out such a course as is outlined below. The post-graduate +or other special departments of instruction, in which, for example, +railroad engineering, marine engineering, and the engineering of cotton, +woolen, or silk manufactures, are to be taught, may be so organized that +some of the lectures of the general course may be transferred to them, +and the instructors in the latter course thus relieved, while the +subjects so taught, being treated by specialists, may be developed more +efficiently and more economically. + +Outlines of these advanced courses, as well as of the courses in trade +instruction comprehended in the full scheme of mechanical engineering +courses laid out by the writer a dozen years ago, and as since recast, +might be here given, but their presentation would occupy too much space, +and they are for the present omitted. + +The course of instruction in this branch of engineering, at the Stevens +Institute of Technology, is supplemented by "Inspection Tours," which +are undertaken by the graduating class toward the close of the last +year, under the guidance of their instructors, in which expeditions they +make the round of the leading shops in the country, within a radius of +several hundred miles, often, and thus get an idea of what is meant by +real business, and obtain some notion of the extent of the field of work +into which they are about to enter, as well as of the importance of +that work and the standing of their profession among the others of the +learned professions with which that of engineering has now come to be +classed. + +At the close of the course of instruction, as originally proposed, and +as now carried out, the student prepares a "graduating thesis," in which +he is expected to show good evidence that he has profited well by the +opportunities which have been given him to secure a good professional +education. These theses are papers of, usually, considerable extent, and +are written upon subjects chosen by the student himself, either with or +without consultation with the instructor. The most valuable of +these productions are those which present the results of original +investigations of problems arising in practice or scientific research +in lines bearing upon the work of the engineer. In many cases, the +work thus done has been found to be of very great value, supplying +information greatly needed in certain departments, and which had +previously been entirely wanting, or only partially and unsatisfactorily +given by authorities. Other theses of great value present a systematic +outline of existing knowledge of some subject which had never before +been brought into useful form, or made in any way accessible to the +practitioner. In nearly all cases, the student is led to make the +investigation by the bent of his own mind, or by the desire to do work +that may be of service to him in the practice of his profession. All +theses are expected to be made complete and satisfactory to the head +of department of Engineering before his signature is appended to the +diploma which is finally issued to the graduating student. These +preliminaries being completed, and the examinations having been reported +as in all respects satisfactory, the degree of Mechanical Engineer is +conferred upon the aspirant, and he is thus formally inducted into the +ranks of the profession. + + +COURSE OF INSTRUCTION IN MECHANICAL ENGINEERING. + + +Robert H. Thurston--July, 1871. + +I. + +MATERIALS USED IN ENGINEERING.--Classification, Origin, and Preparation +(where not given in course of Technical Chemistry), Uses, Cost. + +_Strength and Elasticity_.--Theory (with experimental illustrations), +reviewed, and tensile, transverse and torsional resistance determined. + +_Forms_ of greatest strength determined. _Testing_ materials. + +_Applications_.--Foundations, Framing in wood and metal. + +FRICTION.--Discussion from Rational Mechanics, reviewed and extended. + +_Lubricants_ treated with materials above. + +Experimental determination of "coefficients of friction." + +II. + +TOOLS.--Forms for working wood and metals. Principles involved in their +use. + +Principles of pattern making, moulding, smith and machinists' work so +far as they modify design. + +Exercises in Workshops in mechanical manipulation. + +Estimates of _cost_ (stock and labor). + +MACHINERY AND MILL WORK.--Theory of machines. Construction. Kinematics +applied. Stresses, calculated and traced. Work of machines. Selection +of materials for the several parts. Determination of _proportions_ of +details, and of _forms_ as modified by difficulties of construction. + +Regulators, Dynamometers, Pneumatic and Hydraulic machinery. Determining +_moduli_ of machines. + +POWER, transmission by gearing, belting, water, compressed air, etc. + +LOADS, transportation. + +III. + +HISTORY AND PRESENT FORMS OF THE PRIME MOVERS. + +_Windmills_, their theory, construction, and application. + +_Water Wheels_. Theory, construction, application, testing, and +comparison of principal types. + +_Air, Gas, and Electric Engines_, similarly treated. + +STEAM ENGINES.--Classification. [Marine (merchant) Engine assumed as +representative type.] Theory. Construction, including general design, +form and proportion of details. + +_Boilers_ similarly considered. Estimates of _cost_. + +_Comparison_ of principal types of Engines and Boilers. Management and +repairing. Testing and recording performance. + +IV. + +MOTORS APPLIED to Mills. Estimation of required power and of _cost_. + +Railroads. Study of Railroad machinery. + +Ships. Structure of Iron Ships and rudiments of Naval architecture and +Ship propulsion. + +PLANNING Machine shops, Boiler shops, Foundries, and manufactories of +textile fabrics. Estimating _cost_. + +LECTURES BY EXPERTS. + +GENERAL SUMMARY of principal facts, and natural laws, upon the thorough +knowledge of which successful practice is based; and general _resume_ +of principles of business which must be familiar to the practicing +engineer. + +V. + +GRADUATING THESES. + +GRADUATION. + +Accompanying the above are courses of instruction in higher mathematics, +graphics, physics, chemistry, and the modern languages and literatures. + + * * * * * + + + + +IMPROVED DOUBLE BOILER. + + +The operation of boiling substances under pressure with more or less +dilute sulphuric or sulphurous acid forms a necessary stage of several +important manufactures, such as the production of paper from wood, the +extraction of sugar, etc. A serious difficulty attending this process +arises from the destructive action of the acid upon the boiler or +chamber in which the operation is carried on, and as this vessel, which +is generally of large dimensions, is exposed to considerable pressures, +it is necessarily constructed of iron or some other sufficiently +resisting metal. An ingenious method of avoiding this difficulty has +been devised, we believe in Germany, and has been put into practice with +a certain amount of success. It consists in lining the iron boiler with +a covering of lead, caused by fusion to unite firmly to the walls of the +boiler, and thus to protect it from the action of the acid. No trouble, +it is stated, is found to arise from the difference in expansion of the +two metals, which, moreover, adhere fairly well; but, on the other hand, +we believe it does actually occur that the repairs to this lead lining +are numerous, tedious, and costly of execution, so that the system can +scarcely be regarded as meeting the requirements of the manufacturer. +It is to secure all the advantages possessed by a lead-lined vessel, +without the drawback of frequent and expensive repairs, that the +digester, of which we annex illustrations, has been devised by Mr. +George Knowles, of Billiter House, Billiter Street. It consists of a +closed iron cylindrical vessel suitable for boiling under pressure, and +containing a second vessel open at the top, and of such a diameter as to +leave an annular space between it and the walls of the outer shell. This +inner receiver, which may be made of lead, glass, pottery, or any +other suitable material, contains the substance to be treated and the +sulphurous acid or other solution in which it is to be boiled. The +annular space between the two vessels is filled with water to the same +level as the solution in the receiver, and the latter is provided with +suitable pipes or coils, in which steam is caused to circulate for +the purpose of raising the solution of the desired temperature, and +effecting the digesting process. At the same time any steam generated +collects in the upper part of the boiler, and maintains an equal +pressure within the whole apparatus. Figs. 1 to 3 show the arrangement +clearly. Within the boiler, a, is placed the receiver, b, of pottery, +lead, or other material, leaving an annular space between it and the +boiler; this space is filled with water. The receiver, b, is furnished +with a series of pipes, in which steam or hot water circulates, to heat +the charge to the desired temperature. These pipes may be arranged +either in coils, as shown at d, Fig. 1, or vertically at d, Fig. 3. The +latter are provided with inner return pipes, so that any condensed water +accumulating at the bottom may be forced up the inner pipes by the +steam pressure and escape at the top. The vessel is charged through the +manhole, e, and the hopper, c, provided with a perforated cover, and is +discharged at the bottom by the valve, f, shown in Figs. 2 and 3. The +upper part of the boiler serves as a steam dome, and the pressure on the +liquid in the receiver and on the water in the annular space is thereby +maintained uniform. The necessary fittings for showing the pressure +in the vessel, water level indicator, safety valve, cocks for testing +solutions, etc., are of course added to the apparatus, but are not +indicated in the drawing. The arrangement appears to us to possess +considerable merit, and we shall refer to it again on another occasion, +after experiments have been made to test its efficiency.--_Engineering_. + +[Illustration: IMPROVED DOUBLE BOILER.] + + * * * * * + + + + +THE GARDNER MACHINE GUN. + + +[Illustration: FIG. 1.--SINGLE BARREL GARDNER MACHINE GUN.] + +The mechanism by which the various functions of loading, firing, and +extracting are performed is contained in a rectangular gun metal case, +varying in dimensions with the number of barrels in the arm. In the +single barrel gun the size of this case is 14 inches in length, 51/2 +inches in depth, and 21/2 inches in width. The top of the box is hinged, +so that easy access can be had to the mechanism, which consists of a +lock, the cartridge carrier, and the devices for actuating them. In the +multiple barrel guns, the frames which, with the transverse bar at the +end, hold the barrels in place, form the sides of the mechanism chamber, +in the front end of which the barrels are screwed. The mechanism is +actuated by a cam shaft worked by a hand crank on one side of the +chamber. By this means the locks are driven backward and forward, +the latter motion forcing the cartridges into place, and the former +withdrawing the empty cartridge case after firing. The extractor hook +pivoted to the lock plunger rises, as the lock advances, over the rim of +the case, but is rigid as the lock is withdrawn, so that the action is +a positive one. The cartridges, which are contained in a suitable +frame attached to the forward part of the breech chamber, pass through +openings in the top plate of the latter, an efficient distribution being +secured by means of a valve having a transverse motion. Each cartridge +as it falls is brought into the axis of the barrel and the plunger, +while the advance motion of the lock forces them into position. In the +five-barrel gun illustrated by Fig. 3 the cartridge feeder contains 100 +cartridges, in five Vertical rows of 20 cartridges each, and these are +kept supplied, when firing, from supplementary holders. Fig. 1 shows the +portable rest manufactured by the Gardner Gun Company. It consists of +two wrought iron tubes, placed at right angles to each other; the front +bar can be easily unlocked, and placed in line with the trail bar, from +which project two arms, each provided with a screw that serves for the +lateral adjustment of the gun. These screws are so arranged as to allow +for an oscillating motion of the gun through any distance up to 15 deg. +The tripod mounting, used for naval as well as land purposes, is shown +in Fig. 2, which illustrates the two barrel gun complete. The five +barrel gun, Fig. 3, is shown mounted on a similar tripod. The length of +this weapon over all is 53.5 inches, the barrels (Henry system) are 33 +inches long, with seven grooves of a uniform twist of one turn in 22 +inches. + +[Illustration: Fig. 2.--TWO BARREL GARDNER GUN.] + +Gardener's five barrel gun in the course of one of the trials fired +16,754 rounds with only 24 jams, and in rapid firing reached a maximum +of 330 shots in 30 seconds. The two barrel gun fired 6,929 rounds +without any jam; the last 3,000 being in 11 minutes 39 seconds, without +any cleaning or oiling.--_Engineering_. + +[Illustration: Fig. 3.--FIVE BARREL GARDNER GUN.] + + * * * * * + + + + +CLIMBING TRICYCLES. + + +The cycle trade is one which has been developed with great rapidity +within the last ten years, and, like all new industries, has called +forth a considerable amount of ingenuity and skill on the part of those +engaged in it. We cannot help thinking, however, that much of this +ingenuity has been misplaced, and that instead of striving after new +forms involving considerable complication and weight, it would have +been better and more profitable if manufacturers had moderated their +aspirations, and aimed at greater simplicity of design; for it must +be remembered that cyclists are, as a rule, without the slightest +mechanical knowledge, while the machines themselves are subject to very +hard usage and considerable wear and tear in traveling over the +ordinary roads in this country. We refer, of course, more especially to +tricycles, which in one form or another are fast taking the place of +bicycles, and which promise to assume an important position in every +day locomotion. Hitherto one of the chief objections to the use of the +tricycle has been the great difficulty experienced in climbing hills, a +very slight ascent being sufficient to tax the powers of the rider to +such an extent as to induce if not compel him in most instances to +dismount and wheel his machine along by hand until more favorable ground +is reached. To obviate this inconvenience many makers have introduced +some arrangement of gearing speeds of two powers giving the necessary +variation for traveling up hill and on the level. We noticed, however, +one machine at the exhibition which seemed to give all that could be +desired without any gearing or chains at all. This was a direct action +tricycle shown by the National Cycle Company, of Coventry, in which the +pressure from the foot is made to bear directly upon the main axle, and +so transmitted without loss to the driving wheels on each side, the +position of the rider being arranged so that just sufficient load is +allowed to fall on the back wheel as to obtain certainty in steerage. +The weight of this machine is much less than when gearing is used, and +the friction is also considerably reduced, trials with the dynamometer +having shown that on a level, smooth road, a pull of 1 lb. readily +moved it, while with a rider in the seat 4 lb. was sufficient. On this +tricycle any ordinary hill can, it is stated, be ascended with great +ease, and as a proof of its power it was exhibited at the Stanley show +climbing over a piece of wood 8 in. high, without any momentum whatever. +We understand that at the works at Coventry a flight of stairs has been +erected, and that no difficulty is experienced in ascending them on one +of these machines.--_The Engineer_. + + * * * * * + + + + +SUBMARINE EXPLORATIONS. + +VOYAGE OF THE TALISMAN. + + +It was but a few years ago that the idea was prevalent that the seas at +great depths were immense solitudes where life exhibited itself under no +form, and where an eternal night reigned. To-day, thanks to expeditions +undertaken for the purpose of exploring the abysses of the ocean, we +know that life manifests itself abundantly over the bottom, and that +at a depth of five and six thousand meters light is distributed by +innumerable phosphorescent animals. Different nations have endeavored to +rival each other in the effort to effect these important discoveries, +and several scientific missions have been sent to different points of +the globe by the English and American governments. The French likewise +have entered with enthusiasm upon this new line of research, and for +four consecutive years, thanks to the devoted aid of the ministry of the +marine, savants have been enabled to take passage in government vessels +that were especially arranged for making submarine explorations. + +[Illustration: THE FRENCH SCIENTIFIC STEAMER TALISMAN.] + +The first French exploration, which was an experimental trip, was made +in 1880 by the Travailleur in the Gulf of Gascogne. Its unhoped +for results had so great an importance that the following year the +government decided to continue its researches, and the Travailleur was +again put at the disposal of Mr. Alph. Milne Edwards and the commission +over which he presided. Mr. Edwards traversed the Gulf of Gascogne, +visited the coast of Portugal, crossed the Strait of Gibraltar, and +explored a great portion of the Mediterranean. In 1882 the same vessel +undertook a third mission to the Atlantic Ocean, and as far as to the +Canary Islands. The Travailleur, however, being a side-wheel advice-boat +designed for doing service at the port of Rochefort, presented none +of those qualities that are requisite for performing voyages that are +necessarily of long duration. The quantity of coal that could be stored +away in her bunkers was consumed in a week, and, after that, she could +not sail far from the points where it was possible for her to coal up +again. So after her return Mr. Edwards made a request for a ship that +was larger, a good sailer, and that was capable of carrying with it a +sufficient supply of fuel for remaining a long time at sea, and that +was adapted to submarine researches. The Commission indorsed this +application, and the Minister of Instruction received it and transmitted +it to Admiral Jaureguiberry--the Minister of the Marine--who at once +gave orders that the Talisman should be fitted up and put in commission +for the new dredging expedition. This vessel, under command of Captain +Parfait, who the preceding year had occupied the same position on the +Travailleur, left the port of Rochefort on the 1st of June, 1883, having +on board Mr. Milne Edwards and the scientific commission that had been +appointed by the Minister of Public Instruction. The Talisman explored +the coasts of Portugal and Morocco, visited the Canary and Cape Verd +Islands, traversed the Sea of Sargasso, and, after a stay of some time +at the Azores, returned to France, after exploring on its way the Gulf +of Gascogne (Fig.). + +[Illustration: FIG.1.--CHART OF THE TALISMAN'S VOYAGE.] + +The magnificent collections in natural history that were collected +on this cruise, and during those of preceding years made by the +Travailleur, are, in a few days, to be exhibited at the Museum of +Natural History. We think we shall be doing a service to the readers of +this journal, in giving them some details as to the organization of the +Talisman expedition as well as to the manner in which the dredgings were +performed. + +[Illustration: FIG.2.--PLAN OF THE VESSEL.] + +The vessel, as shown by her plan in Fig. 2, had to undergo important +alterations for the cruise that she was to undertake. Her deck was +almost completely freed from artillery, since this would have encumbered +her too much. Immediately behind the bridge, in the center of the +vessel, there were placed two windlasses, one, A, to the right, and the +other, B, to the left (Fig. 2). These machines, whose mode of operation +will be explained further along, were to serve for raising and lowering +the fishing apparatus. A little further back there were constructed +two cabins, G and HH. The first of these was designed to serve as a +laboratory, and the second was arranged as quarters for the members of +the mission. + +The sounding apparatus, the Brothergood engine for actuating it, and the +electric light apparatus were placed upon the bridge. The operating +of the sounding line and of the electric light was therefore entirely +independent of that of the dredges. On the foremast, at a height of +about two meters, there was placed a crane, F, which was capable of +moving according to a horizontal plane. Its apex, as may be seen from +the plan of the boat, was capable of projecting beyond the sides of the +ship, to the left and right. To this apex was fixed a pulley over which +ran the cable that supported the dredges or bag-nets, which latter were +thus carried over the boat's sides. + +[Illustration: FIG.3.--DIAGRAM OF THE THIBAUDIER SOUNDING APPARATUS.] + +The preliminary operation in every submarine exploration consists in +exactly determining the depth of the sea immediately beneath the vessel. +To effect this object different sounding apparatus have been proposed. +As the trials that were made of these had shown that each of them +possessed quite grave defects, Mr. Thibaudier, an engineer of the navy, +installed on board the Talisman last year a new sounding apparatus which +had been constructed according to directions of his and which have given +results that are marvelous. The apparatus automatically registers the +number of meters of wire that is paid out, and as soon as the sounding +lead touches bottom, it at once stops of itself. This apparatus is shown +in Fig. 4, and a diagram of it is given in Fig. 3, so that its operation +may be better understood. The Thibaudier sounding apparatus consists of +a pulley, P (Fig. 3), over which is wound 10,000 meters of steel wire +one millimeter in diameter. From this pulley, the wire runs over a +pulley, B, exactly one meter in circumference; from thence it runs to a +carriage, A, which is movable along wooden shears, runs up over a fixed +pulley, K, and reaches the sounding lead, S, after traversing a guide, +g, where there is a small sheave upon which it can bear, whatever be the +inclination of the boat. The wheel, B, carries upon its axle an endless +screw that sets in motion two toothed wheels that indicate the number +of revolutions that it is making. One of these marks the units and the +other the hundredths (Fig. 5). This last is graduated up to 10,000 +meters. As every revolution of the wheel, B, corresponds to one meter, +the number indicated by the counter represents the depth. Upon the axle +of the winding pulley there is a break pulley, p. The brake, f, is +maneuvered by a lever, L, at whose extremity there is a cord, C, which +is made fast to the carriage, A. When, during the motions due to +rolling, the tension of the steel wire that supports the lead diminishes +or increases, the carriage slightly rises or falls, and, during these +motions, acts more or less upon the brake and consequently regulates the +velocity with which the wire unwinds. When the lead touches bottom, the +wire, being suddenly relieved from all weight (which is sometimes as +much as 70 kilos), instantly stops. + +[Illustration: FIG. 4.--GENERAL VIEW OF THE SOUNDING APPARATUS IN THE +"TALISMAN:"] + +The maneuver of this apparatus may be readily understood. The apparatus +and its weights are arranged in the interior of the vessel. A man bears +upon the lever, L (Fig. 3), and the counter is set at zero. All being +thus arranged, the man lets go of the break, and the unwinding then +proceeds until the lead has touched bottom. During the operation of +sounding, the boat is kept immovable by means of its engine, so that the +wire shall remain as vertical as possible. The bottom being reached, the +unwinding suddenly ceases, and there is nothing further to do but read +the indication given by the differential counter, this giving the depth. + +[Illustration: FIG. 5.--APPARATUS FOR MEASURING THE LENGTH OF THE WIRE +PAID OUT.] + +Near the winding pulley, there is a small auxiliary engine, M, which +is then geared with the axle of the said pulley, and which raises the +sounding apparatus that has been freed from its weight by a method that +will be described further along. + +We have endeavored in Fig. 4 to show the aspect of the bridge at the +moment when a sounding was about being made. From this engraving (made +from a photograph) our readers may obtain a clear idea of the Thibaudier +sounding apparatus, and understand how the wheel over which the wire +runs is set in motion by the Brothergood engine.--_La Nature_. + + * * * * * + + + + +CABLE GRAPNEL. + + +Some improvements have recently been made by Mr. Alexander Glegg and the +inventor in the well-known Jamieson grapnel used for raising submerged +submarine cables. The chief feature of the grapnel is that the flukes, +being jointed at the socket, bend back against a spring when they catch +a rock, until the grapnel clears the obstruction, but allow the cable +to run home to the crutch between the fluke and base, as shown in the +figures. In the older form the cable was liable to get jammed, and cut +between the fixed toe or fluke and the longer fluke jointed into it. +This is now avoided by embracing the short fluke within the longer one. +The shank, formerly screwed into the boss, is now pushed through and +kept up against the collar of the boss, by the volute spring, which at +the same time presses back the hinged flukes after being displaced by +a rock. The shank can now freely swivel round, whereas before it was +rigidly fixed. The toes or flukes are now made of soft cast steel, which +can be straightened if bent, and the boss is made of cast steel or +gun-metal. + +[Illustration: JAMIESON'S GRAPNEL.] + + * * * * * + + + + +WRETCHED BOILERMAKING. + + +_To the Editor of the Scientific American_: + +As long as I have been a reader of the SCIENTIFIC AMERICAN I have been +pleased with the manner in which you investigate and explain the cause +of any boiler explosion which comes to your knowledge; and I have +rejoiced when you heaped merited censure upon the fraudulent +boilermaker. In your paper in December last you copied a short article +on "Conscience in Boilermaking," in which the writer, after speaking +of the tricks of the boilermaker in using thinner iron for the center +sheets than for the others, and in "upsetting" the edges of the plates +to make them appear thicker, goes on to say: "We call attention to this, +because the discovery of such practice has made serious trouble between +the boilermaker and the steam user. We would not believe that there were +men so blind to the duties and obligations which rest upon them as +to resort to such practice, but the careful inspector finds all such +defects, and in time we come to know whose work is carefully and +honestly done, and whose is open to suspicion. In States and cities +where inspection laws are in force that give the methods and rules by +which the safe working pressure of a boiler is calculated, there is no +alternative except to follow the rules; and if certain requirements +regarding construction are a part of the law, there is no authority or +right to depart from it, and yet there are boilermakers who try to force +their boilers into such localities when their work is not up to the +requirements of the law." + +Now, if some boilermakers are so dishonest as to try and impose upon the +locomotive engineer, who they know will carefully examine every part of +his boiler, and who is able to detect any flaw, it is not to be expected +that the farmer will escape. Nor does he. The great number of explosions +of boilers used in thrashing and in other farm work proves that there +are boilermakers who "force their boilers into such localities +when their work is not up to the requirements of the law." And the +boilermaker, if he be dishonest, is doubly tempted if the broad width of +a continent intervenes between him and the farmer for whom his work is +intended, and if in the place where the boiler is to be used there are +no inspection laws in force. The farmer who lives many miles from a +city, and who has no means of testing any boiler he may purchase, +is wholly at the mercy of the boilermaker, and must run it until it +explodes or time proves it to have been honestly made. Then, again, +there are boilermakers who, although making boilers of good iron and of +the proper thickness, finish them off so badly that the farmer is put to +great inconvenience and expense to put them in working order. Two years +ago I purchased a straw-burning engine and boiler made by an Eastern +firm. Before it had run ten days the boiler began to leak at the +saddle-bolt holes. The engineer tightened the nuts as far as possible, +but could not stop the leaks, which at last became so bad that we had to +stop work and take the engine to the shop. Upon taking off the saddle +and taking out the bolts it was discovered that they were too small for +the holes in the boiler, and that they had been wrapped with candle wick +and white lead to make them fill the holes, and that a light washer had +been put on each bolt between the head and the inside of the boiler. +This washer kept the lead in its place, and prevented the boiler from +showing a leak when first fired up. The water pipes in the fire-box soon +gave out and became utterly useless. Upon inquiring of the patentee of +this straw-burning device, who was supposed to have put it in my boiler, +he stated that he had had nothing to do with it, but that it was put in +by the firm selling these engines, and "as cheaply as possible." Before +I got this boiler and engine in fair running order I had spent hundreds +of dollars and had to do entirely away with the water grates. + +Last summer, needing another tharshing engine, I was induced to buy +one of the same make as my old one, but with a different straw-burning +device. The firm who sold it to me agreed that it should have none of +the faults of the old one. Well, I got it, and, upon hauling it out to +my ranch, and getting up steam, I found it to be much worse than the +first one I had bought. The boiler leaked at nearly every hole where +a tap had been screwed into it. It took an engineer, a boilermaker, a +blacksmith, and a fireman several days to get it in shape so that we +could use it at all; and after we did start up, the boilermaker had +to be sent for several times to stop new leaks that were continually +showing themselves. + +I send you by this mail for your inspection one of the saddle bolts and +one of the bolts taken out of the piston, and also the certificates of +the engineer, boilermaker, and machinist who repaired the boiler. In +justice to my fellow-farmers I ought to publish these certificates and +the names of these boilermakers to the world, but, for the present at +least, I refrain from so doing. These boilermakers will see this article +and they will know, if the public does not, for whom it is intended. If +it has the effect of making them exercise more care in the construction +and fitting up of their engines and boilers, I have not written in vain. + +D. FREEMAN. + +Los Angeles, Cal., March 7,1884. + +[The two bolts and the certificates above referred to accompany the +letter of Mr. Freeman. We can only wonder how it was that, after having +been treated as he relates in the first instance, he should have had any +further business with parties who would send out such boilers, for the +testimony of the engineer and workmen make the case even stronger than +Mr. Freeman has put it.--ED.] + + * * * * * + + + + +A THREADED SET COLLAR. + + +There are cases where a long screw must be rotated with a traversing nut +or other threaded piece traveling on its thread a limited and variable +distance. At one time the threaded nut or piece may be required to +go almost the entire length of the screw, and at another time a much +shorter traverse would be required. In many instances the use of side +check nuts is inconvenient, and in some it is impossible. One way of +utilizing the nut as a set collar is to drill through its side for a set +screw, place it on its screw, pour a little melted Babbitt metal, or +drop a short, cold plug of it into the hole, tap the hole, and the tap +will force the Babbitt into the threads. + +Insert the set screw, and when it acts on the Babbitt metal it will +force it with great friction on to the thread without injuring the +thread; and when the set screw tension is released, the nut turns +freely. A similar and perhaps a better result may be obtained by +slotting the hole through the nut as though for the reception of a key. +Secure a key (preferably of the same material as the nut) by slight +upsetting at its ends, and then thread the nut, key, and all. Place +a set screw through the nut over the threaded key, and the job is +complete. + + * * * * * + + + + +PNEUMATIC MALTING. + + +The lethargy in the malting trade, and in all matters relating to +malting processes, induced by two centuries of restrictive legislation, +is being gradually shaken off by the malting industry under the new law. +For many years nearly all improvements in malting processes originated +abroad, as numberless Acts of Parliament fettered every process and the +use of every implement requisite in a malt-house in this country. The +entire removal of these legislative restrictions gives an opportunity +for improved processes, which promises to open up a considerable +field for engineering work, and to develop a very backward art by the +application of scientific principles. The present time is, therefore, +one of more material change than malting has ever experienced. + +[Illustration: PNEUMATIC MALTING AT TROYES. Fig. 1.] + +Of the numerous improvements effected in the past few years, those made +by M. Galland in France, and more recently by M. Saladin, are by far the +most prominent. M. Galland originated what is known as the pneumatic +system eight or nine years ago. This system is carried out at the +Maxeville brewery, near Nancy. + +[Illustration: PNEUMATIC MALTING AT TROYES. Fig. 2.] + +Since that time further improvements have been made by M. Galland; but +more recently great advances have been made in the system by M. +Saladin. He has developed the practice of the leading principle, and in +conjunction with Mr. H. Stopes, of London, has added improved kilns and +various mechanical apparatus for performing the work previously done by +hand. He has also devised a very ingenious machine for cooling the moist +air by which the process is carried on. + +[Illustration: FIG. 4.--ECHANGEUR AND TURNING MACHINE.] + +At the recent Brewery Exhibition, some of the machinery used in these +new maltings was shown in action by Messrs. H. Stopes & Co., together +with drawings of a malting constructed at Troyes for M. Bonnette under +M. Saladin's instructions. This malting is the third constructed for the +same firm, the others being at Nancy. That at Troyes we now illustrate. +We will not occupy space by a general description of the pneumatic +system, one great feature in which is the continuous manufacture of malt +throughout the year instead of only from five to eight months of the +year, as it will be gathered from the following description of the +Troyes malting: + +[Illustration: FIG. 5.--ECHANGEUR, AXIAL SECTION.] + +In our engravings, Figs. 1, 2, and 3, the letter A indicates the +germinating cases; B, Saladin's patent turning screws; C A, air +channels; D, passages; E R, main driving shafts; e, pulleys; F, metal +recesses to fit turning screws; G, elevators; H, trap doors; I, air +channels; J, openings to growing floor for air; K S, engines and fan +room; L N, fans, supply and exhaust; T, boiler; U, chimney; f, well. The +capacity of the malting is 130 qr. malt every day. This is equivalent to +an English house of 520 qr. steep. The whole space occupied is the area +necessary for kilns, malt and barley stores, engine and boiler house, +and fans. No additional area is required for germinating floors, as ten +germinating cases, A, are placed in the basement below the kilns and +stores. The building is of brick, with the internal walls below the +ground line resting upon cast iron columns and rolled joists. The +germinating cases, A A, are of iron; the bottoms are double. One of +perforated plate is placed 6 inches above the bottom. These plates admit +of draining the corn if the germinating case is used as a steeping +cistern also. Their chief object is, however to admit of ready +circulation of the air by the means presently to be described. Large +channels, A a, serve as drains for moisture and to convey the air to or +from the growing corn. Between each case is a passage, D, enabling the +maltster to have free access to the corn at all points. + +[Illustration: FIG. 6.--ECHANGEUR TRANSVERSE SECTION.] + +With the exception of the driving shaft, E, all the machinery is in +duplicate, so that the possibility is remote of any breakdown that would +seriously affect the working of the house. This is necessary, as should +the fans, L N, be stopped for twenty-four hours the corn germinating +at a depth exceeding 30 inches would heat and impair its vitality. The +boilers, T, and engines, S, are of the common type of 20 horse power +nominal. The fans, L N, are the Farcot patent, illustrated a short time +since in our pages. The lower floors of the kilns are provided with +the Schlemmer patent mechanical turners. The turners, Fig. 4, in the +germinating cases are Saladin's patent. + +[Illustration: FIG. 7.--ECHANGEUR, SECTIONAL PLAN.] + +The germination of the grain is effected by means of cool moist air +provided by the fan described and the cooler and moistener--Figs. 5, 6, +and 7, herewith--known as an _echangeur_. As the germinating grain has +a depth of from 30 inches to 40 inches some pressure is required, and +mechanical means are necessary for efficient and economical turning. +The _echangeur_ is a very ingenious application of the well understood +rapidity of evaporation of any liquid when spread out in very thin +layers over large surfaces and exposed to a current of air. It consists +of a cylinder, or series of cylinders, of increasing diameter, placed +one within another. Each consists of finely perforated sheet iron. They +are placed in a trough of water, just sufficiently immersed to insure +complete wetting. When rotated at a slow speed, the surfaces of all the +cylinders are kept just wetted. A volume of air is either driven or +drawn through, as may be required for any particular purpose. In the +model malting, as shown at Fig. 4, taken from that shown at the Brewery +Exhibition, the air was driven through the _echangeur_ and thence +through the germinating barley. Here or as employed in the malting +illustrated, the air in its passage comes first into contact with the +moistened cylinders, and if hot and dry it becomes moist and cool, for +the constant evaporation upon the cylinders has a very considerable +refrigerating effect. + +This was well known to the Egyptians over four thousand years ago, and +the porous bottle--_gergeleh_--of Esnch has been made until the present +day, to keep the drinking water cool and fresh. The _echangeur_ is +like a gigantic gergeleh, and by increasing the size and number of the +cylinders, and causing the water in the moistening trough to circulate, +any volume of air can be wetted to the saturation limit corresponding to +its temperature. It will be seen that this apparatus gives the maltster +complete control of the humidity and heat as well as volume of the air +driven through germinating corn. + +[Illustration: Fig. 8.] + +The turning apparatus is shown by Fig. 4, and consists, as will be seen, +of a cylindrical frame provided with rollers which run on rails at the +edge of the germinating cases. It is carried to and fro from either end +of the case by compensating rope gearing which at the same time gives +motion to the gearing actuating the turning screws. These screws do not +quite touch the bottom of the germinating case, but are provided with a +pair of small brushes, as shown in the annexed engraving, Fig. 8, which +just skim it. The apparatus shown has but three of these screws, but the +cases are generally made wide enough for six. The kilns are double, +each possessing two floors, and worked upon the Stopes' system. The +construction of the furnaces is of the ordinary French pattern. The +arrangement of the house permits of great regularity in working. Every +day 130 qrs. of barley is screened, sorted, cleaned, and passed into a +steeping cistern. When sufficiently steeped it runs through piping into +the germinating case, which, in the natural order of working, is empty. +Here it forms the couch. When it is desirable to open couch a small +amount of air is forced through the grain by opening the trap door +connected with the main air channel. This furnishes the growing corn +with oxygen, removes the carbonic acid gas, and regulates temperatures +of the mass of grain. Later the Saladin turner is put in motion about +every eight to twelve hours. The screws in rotating upon their axes are +slowly propelled horizontally. They thus effectually turn the grain and +leave it perfectly smooth. This turning prevents matting of the roots, +the regulation of temperature and exposure to air being effected +by means of the cold air from the _echangeur_. When the grain is +sufficiently grown it is elevated to the kilns. For forty hours it +remains upon the top floor. It is then dropped upon the bottom floor, a +further charge of green corn following upon the top floor. The benefit +is mutual. The bottom floor is maintained at an even temperature, being +virtually plunged in an air bath; free radiation of heat is prevented; +the top surface of the malt is necessarily nearly as warm as that next +the wires, which in its turn is subject to lower heats than would be +necessary if free radiation from the surface was allowed. The top floor +is by the intervention of the layer of malt between it and the fire +prevented it from coming into direct contact with heat of a dangerous +and damaging degree. The same heat which is used to dry one floor, and +in an ordinary kiln passes at once into the air as waste, is the best +possible description of heat, namely, very slightly moistened heated +air, to remove the moisture from the second layer of malt at a low +temperature. It is of vital importance to retain this green malt at a +low heat so long as any percentage of moisture exceeding, say, 15 per +cent, is retained by the corn. + +The regulation of temperature is shown by the diagrams, Figs. 9 and 10: + +[Illustration: Fig. 9.] + +[Illustration: Fig. 10.] + +The distribution of the heated air in the kiln is rarely as uniform as +is supposed, the temperature of the malt on drying floor being very +different at different parts. In illustration of this, the following may +be taken from a statement by Mr. Stopes of the results of an examination +of the temperatures at different parts of a drying floor in a kiln in +Norfolk: "A malting steeping 105 qr. every four days has a kiln 75 +feet by 36 feet; an average drying area of under 26 feet per qr. The +consequent depth of green malt when loaded is over 10 inches. The total +area of air inlets is less than 27 feet super. The air outlet exceeds +117 feet, a ratio of 13 to 3. The capacity of head room equals 44,550 +feet cube. The area of each tile is 144 inches, with 546 holes, giving +an effective air area of some 32 inches. The ratio of non-effective +metallic surface to air space is thus 9 to 2." The Casella anemometer +gave no indications at several points, and fluctuating up and down +draughts were observable at many others, especially at two corners and +along the center. "The strongest upward draught pulsated with the gusts +of wind and ranged from 30 feet to 54 feet per minute, a down draught of +equal intensity occurring at intervals at the same spot, notwithstanding +the fact that the air was rushing in at the inlets below the floor at +the high velocity of 785 feet per minute. The temperatures of the drying +malt and superimposed air consequent upon the conditions thus indicated +were naturally as follows: At B, the place supposed to be hottest: Heat +of malt touching tiles, 216 deg.; heat of malt 1 inch above tiles, 167 +deg.; heat of malt 3 inches above tiles 154 deg.; heat of malt 4 inches +above tiles, 152 deg.; heat of malt 5 inches above tiles, 142 deg.; heat +of malt on surface, 112 deg. At A, the place supposed to be coldest: +Heat of malt next tiles, 174 deg.; heat of malt 2 inches above tiles, +143 deg.; heat of malt 4 inches above tiles, 135 deg.; heat of malt on +surface, 104 deg.; the heat of the air 3 feet above tiles, 84 deg.; the +heat of the air 5 feet above tiles, 82 deg. Fig. 9 shows the temperature +at twenty-six points close to the tiles, taken with twelve registered +and accurate thermometers in the space of fifteen minutes." These and +other similar tests have led to the conclusion that the best malt drying +cannot be done on a single floor. + +Fig. 10 is a similar diagram showing the temperatures on a drying floor +of kiln at Poole, Dorset, altered to Stopes' system of drying. The +temperature at different depths of the drying grain was as follows: Malt +at surface of tiles, 142 deg.; malt at 1 inch above tiles, 142 deg.; +malt at 2 inches above tiles, 142 deg.; malt at 4 inches above tiles, +141 deg.; malt on surface, 140 deg. + +The advantages of the Saladin system over that hitherto working in +Britain are numerous, and are thus enumerated by Messrs. Stopes & Co. +who are agents for M. Saladin: The area occupied by the building does +not equal one-third of that otherwise required. The actual growing-floor +space is only about one-seventh, and the number of workmen is ruled +necessarily by the size of the house, but on an average is reduced +two-thirds; but the employment of much more power is necessary, and the +power is used at more frequent intervals. The use of plant and premises +is continuous, the processes of malting being equally well performed +during the summer months. The further advantage of this is that brewers +secure entire uniformity in age of malt. By the English system the +stocks of finished malt necessarily fluctuate largely. All grain is +subjected to the same conditions of surrounding air, exposure, and +temperature. The volume of air supplied to the germinating corn is +entirely under control, as are also its temperature and humidity. When +germination is arrested and the green malt is drying, the double kilns +insure control of the temperatures of the corn in the kilns. The +infrequency of turning the germinating grain benefits the growth of the +roots and the development of the plumule, besides saving much labor. No +grains are crushed or damaged by the feet or shovels of workmen. The air +supplied to the corn can be inexpensively freed from disease germs +and impurities. The capital needed for malting can be reduced by the +diminished cost of installation, and the reduced stocks of malt on hand. +The quality of the malt made is considerably improved. The percentages +of acidity are much reduced. The stability of the beer is increased, +and a greater percentage of the extractive matter of the barley is +obtainable by the brewer.--_The Engineer_. + + * * * * * + + + + +NON-SPARKING KEY. + + +Profs. Ayrton and Perry lately described and exhibited before the +Physical Society their new ammeters and voltmeters, also a non-sparking +key. The well known ammeters and voltmeters of the authors used for +electric light work are now constructed so as to dispense with +a constant, and give the readings in amperes and volts without +calculation. This is effected by constructing the instruments so +that there is a falling off in the controlling magnetic field, and a +considerable increase in the deflecting magnetic field. The deflections +are thus made proportional to the current or E.M.F. measured. The +ingenious device of a core or soft iron pole-piece, adjustable between +the poles of the horseshoe magnet, is used for this purpose. By means of +an ammeter and voltmeter used conjointly, the resistance of part of the +circuit, say a lamp or heated wire, can be got by Ohm's law. Profs. +Ayrton and Perry's non-sparking key is designed to prevent sparking with +large currents. It acts by introducing a series of resistance coils +determined experimentally one after the other in circuit, thereby +cutting off the spark. + + * * * * * + + + + +NEW INSTRUMENTS FOR MEASURING ELECTRIC CURRENTS AND ELECTRO-MOTIVE +FORCE. + +By Messrs. R. E. CROMPTON and GISBERT KAPP. + +[Footnote: Paper read before the Society of Telegraph Engineers, 14th +February, 1884.] + + +In consequence of the rapid development of that part of electrical +science which may be termed "heavy electrical engineering," reliable +measuring instruments specially suitable for the large currents +employed in lighting and transmission of energy have become an absolute +necessity. As usual, demand has stimulated supply, and many ingenious +and useful instruments have been invented, the manufacture of which +forms at the present day an important industry. Mr. Shoolbred, in a +paper which he recently read before this Society, gave a full and +interesting account of the labors of our predecessors in this field. +To-day we add to the list then given a class of instruments invented by +us, examples of which are now before you on the table. We have preferred +to call them current and potential indicators in preference to meters, +considering that the latter term, or rather termination, ought to be +applied rather to integrating instruments, which the necessities of +electric lighting, we believe, will soon bring into extensive use. The +principal aim in the design of these indicators has been to obtain +instruments which will not alter their calibration in consequence of +external disturbing forces. If this object can be attained, then it will +be possible to divide the scale of each instrument directly into amperes +or volts, as the cause may be, and thus avoid the use of a coefficient +of calibration by which the deflection has to be multiplied. This is an +important consideration when it is remembered that in many cases +these instruments have to be used by unskilled workmen, to whom a +multiplication involving the use of demical fractions is a tedious and +in some cases even an impossible task. + +[Illustration: FIG. 1. FIG. 2.] + +All measurements are comparative. We measure weights or forces by +comparison with some generally known and accepted unit standard +weights, lengths, areas, and volumes, by comparison with a unit length, +resistance by a standard ohm, and so forth. In the same way currents +could be measured by comparison with a standard current: but this +would be a troublesome process, not only on account of the apparatus +necessary, but also because it would be a matter of some difficulty to +have a standard current always ready for use. In general, measurement +by direct comparison with a standard unit is discarded for the more +indirect method of measuring not the current itself, but its chemical, +mechanical, or magnetic effect. The chemical method is very accurate if +a proper density of current through the surface of the electrodes be +used,[1] but since it requires a considerable time, and, above all, an +absolutely constant current, its use is almost entirely restricted +to laboratory work and to the calibration of other instruments. For +practical ready use, instruments employing the mechanical or magnetic +effect of the current are alone suitable. We weigh, so to speak, the +current against the force of a magnet, of a spring, or of gravity. +The measurement will be exact if the thing against which we weigh or +counterbalance the current itself retains its original standard value. +Where permanent magnets or springs are used as a balancing force, this +condition of constancy in our weights and measures is not always fully +maintained, and to make matters worse, there is no visible sign by which +a change, should it have occurred, can be readily detected. A spring +may have been overstrained or a steel magnet may have become weakened +without showing the least alteration in outward appearance. To overcome +this difficulty, the obvious remedy is not to use springs or steel +magnets at all, but to substitute for these some other force which +should be either absolutely constant, such as the force of gravity, or +at least should, vary only within narrow limits, and this in accordance +with a definite law. This latter condition can be fulfilled by the +employment of electro-magnets. + +[Footnote 1: According to recent experiments made by Dr. Hammerl, the +density of current in a copper voltameter should be half an ampere per +square inch of surface.] + +[Illustration: FIG 3.] + +To imitate with an electro magnet as nearly as possible a permanent +magnet, so that the former can be used to replace the latter, it is +necessary that the magnetism in the iron core should remain constant. +This could, of course, be done by exciting the electro magnet with a +constant current from a separate source. (In a recent note to the Paris +Academy of Science, M.E. Ducretet described a galvanometer with steel +magnet, which is surrounded by an exciting coil. When recalibration +appears necessary, a known standard current from large Daniell cells is +sent through this coil during a certain time, and thus the magnet is +brought back to its original degree of saturation. M. Ducretet also +mentions the use of a soft iron bar instead of a steel magnet, in which +case the current from the Daniell cells must be kept on during the time +an observation is taken.) But such a system would appear to be too +complicated for ready use. Moreover, some sort of indicator would be +required by which we could make sure that the exciting current has the +normal strength. + +[Illustration: FIG 4.] + +The plan we adopt is to excite the electro magnet by the whole or a part +of the current which is to be measured. Since this current varies, the +power exciting the core of the electro magnet must also vary; and since +we require the core to have as nearly as possible a permanent magnetic +force, we are brought face to face with the question, whether an electro +magnet can be constructed that has a constant moment under varying +exciting currents. This question has been answered by the well known +experiments of Jacobi, Dub, Mueller, Weber, and others. To get an +absolutely constant magnetic moment, is not possible, but between +certain limits we can get a very near approximation to constancy. + +[Illustration] + +The relation between exciting power and magnetic moment is very +complicated, depending not only on the dimensions and shape of the core +and the manner of winding, but also on the chemical constitution of the +iron of the core. It is not possible, or at least it has hitherto not +been found possible, to embody all these various elements into an exact +mathematical formula, which would give the magnetic moment as a function +of the exciting current; but the above mentioned experiments have shown +that within certain limits, and in the neighborhood of the point of +saturation, the relation between the two is that of an arc to its +geometrical tangent. It will be seen that for large angles the arc +increases much slower than the tangent; that is, for strongly excited +cores, a very large increase of the exciting current will produce only +a slight increase of magnetic moment. If Mueller's formula were correct +for all currents, absolute saturation could only be reached with an +infinite current. Whether this be the case or not, it is certain that +the greater the exciting current the less will a variation in it affect +the magnetic moment of the core. To imitate as nearly as possible +permanent steel magnets, it is therefore necessary to use electro +magnets, the cores of which are easily saturated. The core should be +thin and long and of the horseshoe type; the amount of wire wound round +it should be large in comparison with the size of the core. + +[Illustration] + +Here is a magnet partly wound which was used in one of our earliest +experiments, but which was a failure on account of having far too much +mass in the core in comparison with the amount of copper wire wound +round it. Since then we have greatly diminished the iron and increased +the copper. The cores of the instruments on the table are composed of +two or three No. 18 b.w.g. charcoal iron wires, and are wound with one +layer of 0'120 inch wire in the case of the current indicators, and +eighteen layers of 0.0139 inch wire in the case of the potential +indicator. If from the diagram, Fig. 1, we plot a curve the abscissae of +which represent exciting current, and the ordinates magnetic moment of +the soft iron core, we find that a considerable portion of the curve +is almost a straight and only slightly inclined line. If it, were a +horizontal straight line the core would be absolutely saturated, but +such as it is, it answers the purpose sufficiently well, for with a +variation of exciting current from 10 to 100 amperes the magnetic moment +varies but slightly. If a small soft iron or magnetic steel needle, _n +s_, be suspended between the poles, S N, of an electro magnet of such +proportions as described above, and the current, after exciting the +electro magnet, _e e_, be lead round the coils, DD, it will be found +that for all currents between 10 and 100 amperes the needle, _n +s_, shows a definite deflection for each current. Here we have a +galvanometer with permanent calibration. In this case the deflection of +the needle will not strictly follow the law of tangents, because the +directing power of the electro magnet is not absolutely constant; but +whatever the exact ratio between deflection and current may be, it must +always remain the same, and to each angle of deflection corresponds one +definite strength of current. + +[Illustration] + +The force with which the electro magnet tends to keep the needle in its +zero position, that is, in line with the poles, S N, is due partly to +the magnetism of the core, which is nearly constant, and partly to the +magnetic influence of the coils, _ee_, themselves, which is, of course, +simply proportional to the current. The total magnetic force acting on +the needle is, therefore, represented by the sum of these two forces, +and consequently not nearly so constant as might be desired in order to +get a good imitation of a tangent galvanometer with a permanent magnet. +In the diagram, Fig. 2, the curve, O A B, represents the magnetic moment +of the iron core, the straight line, ODE, that of the exciting coils per +se, and the dotted line, O F M, the sum of the two, obtained by adding +for every current, O C, the respective ordinates, CD and C A. + + CF = CD + CA + +The rise of this curve shows that the force which tends to bring the +needle back to its zero position increases with the current, though at a +slower ratio than the deflecting force of the current. It follows from +this that for large currents the increment in the angle of deflection is +comparatively small, and the divisions on the scale whereon the current +is to be read off would come too near together to allow accurate +readings to be taken. In other words, the range of accurate reading in +an instrument so constructed would only be limited. But it is very easy +to eliminate the magnetic effect of the coils of the electro magnet on +the needle, by introducing an opposite magnetic effect, so that only +that part of the force remains which belongs to the soft iron core +proper. One way of doing this is by surrounding the needle with a coil, +the plane of which is at right angles to the line, S N, and coupling +this coil in series with the deflecting coil, D D. If the proportions +of this transverse coil and the direction of the current through it +be properly chosen, its magnetic effect can be made to exactly +counterbalance that of the exciting coils, _e e_, without perceptibly +weakening the magnetism of the iron core. But instead of employing two +coils, one parallel and the other transversely to the zero position of +the needle, we can obtain the same result in a more simple manner with +one coil only, if this be placed at such an angle that its magnetic +effect can be substituted for the combined effects of the two coils. In +other words, we set the deflecting coil, D D, at a certain angle to the +zero position of the needle. + +A similar arrangement, though not precisely for the same purpose, has +already been suggested and tried by Messrs. Deprez, Carpentier, Ayrton, +and Perry, in galvanometers with permanent steel magnets. If the coil, +D D, be so placed, the deflecting force which now acts obliquely can be +considered as the resultant of two forces, one acting at right angles to +the line, S N, as in an ordinary galvanometer, and the other parallel to +this line, but in a sense opposed to the action of the electro magnet +and its exciting coils. If the angle of obliquity be so chosen that this +latter component exactly equals the magnetic effect of the exciting +coils _per se_, an equality which holds good for all currents, then we +shall have an almost perfect imitation of a tangent galvanometer with +permanent magnets. But we can go a step further than this; we can +overbalance the exciting coils by setting the deflecting coil at a +greater angle than necessary for the mere elimination of the former, and +thus attain that an increase of current results in a slight weakening of +the field in which the needle swings, thus allowing the increment of the +angle of deflection to be comparatively large even for large currents. +In this way it is possible to obtain a more evenly divided scale than +in the case when the deflection follows the law of tangents, as in an +ordinary tangent galvanometer. This principle of overbalancing the +exciting coils is shown on diagram, Fig. 2. The straight line, O G, +represents the magnetic effect on the needle of that component of the +deflecting force which is parallel, but in sense opposed to S N; +as mentioned above, the magnetic effect of the exciting coils is +represented by the straight line, O E. The combined effect of these two +forces on the needle is represented by the line, O K, the ordinates +of which must be deducted from those of the curve, O A B, in order to +obtain the total directing force due to each current. This is shown by +the curve, O P Q, shown in a thick full line. This curve shows how +the directing force or strength of field in which the needle swings +decreases with an increasing current. That this does actually take place +can easily be proved by experiment. + +Fig. 4 shows two curves; the one drawn in a full line is obtained +by plotting the deflection in degrees of the needle of a potential +indicator as abscissae, and the corresponding electromotive forces +measured simultaneously on a standard instrument as ordinates; the +dotted line shows what this curve would be with an ordinary tangent +galvanometer. + +The needle of the potential indicator is mounted at the lower end of +a steel axle, to the upper end of which is fastened a light aluminum +pointer, whereby the deflection of the needle can be read off on a scale +divided directly into volts. The scale is placed within a circular dial +plate with glass cover, giving sufficient room for the pointer to swing +all round, and the needle is placed within a central tube fitting it +closely, which acts as a damper and so makes the instrument almost +dead beat. Tube and dial are in one casting. The electro magnet is of +horseshoe form fastened to a central tubular stand, which also serves +to support the two deflecting coils, one on either side of it. The tube +within which the magnetic needle swings is inserted into the stand, +which is bored out to the external diameter of the tube. The electro +magnet and deflecting coils are wound with from 50 to 100 ohms of fine +insulated copper wire, and an additional resistance coil of from 450 +to 900 ohms of German silver is added, which can, however, be short +circuited by depressing a key when the instrument has to be used for +reading low electromotive forces. In this case the indication of the +pointer must be divided by ten. If a current be sent through the +instrument the wrong way, the needle turns through an angle of 180 deg., and +thus brings the pointer to the side of the dial opposite to where the +scale is. In this position no reading can be taken, and to facilitate +the sending of the current in the right direction a commutator is added, +and the same is so coupled up that when the pointer stands over the +scale the handle on the commutator points to the positive terminal +screw. There is a limit of electromotive force below which the indicator +fails to give reliable readings. For instance, an instrument wound with +100 ohms of copper wire and 900 ohms of German silver can be used for +electromotive forces varying between 300 and 3 volts, but would not be +reliable for measuring less than 3 volts. + +For very exact measurements the instrument should be placed north and +south, in the same position in which it was calibrated. Two different +patterns of current indicators are on the table; one with double needles +suspended on a point in the way compass magnets are suspended, the other +with one lozenge shaped needle mounted on an axle and pivoted on jewels, +in every way similar to the needle of the potential indicator first +described. + +For measurements of currents from 10 amperes upward, there is no need +to employ a complete coil as the deflecting agent; one half-coil or one +strip passing close under the needle gives sufficient deflecting force, +and thus the construction of the instrument is rendered extremely +simple. The current, after entering at one of the flat electrodes, +splits in two parts, each part passing round the winding of an electro +magnet of horseshoe form, the similar poles of both magnets pointing +toward each other and toward the needle. After traversing the winding, +the current unites again, and passes through a metal strip close under +the needle, and finally out of the instrument by the other electrode, +which lies close under that at which the current entered, but is +insulated from it by a sheet of fiber. The metal strip is set at an +angle, to balance or overbalance, as may be preferred, the magnetic +influence of the exciting coils. The effect of this overbalancing is +shown in Fig. 5, where the full curve represents the current as a +function of the deflection--obtained by comparison with a standard +instrument--and the dotted curve shows what that relation between +deflection and current would be if the law of tangents held good for +these instruments. It will be seen that, about the middle of the scale, +the dotted line coincides nearly with the full line, while at the +extreme end of the scale the dotted line is higher. From this follows, +that if we compare our indicator from which this curve was taken with +any form of tangent instrument showing an equal angle of deflection at +the medium reading, it will be seen that the needle of our indicator +will be deflected to a greater angle at high readings than that of the +tangent galvanometer. Consequently, the divisions on the scale will +be widest apart in our instruments, which greatly facilitates high +readings. + + * * * * * + + + + +SECONDARY BATTERIES. + + +The Consolidated Electric Light Company has now completed the secondary +battery which has for some time engaged the attention of its officers, +and their regular manufacture and use for electric lighting stations +have been fairly entered upon. Among other places to which the batteries +have been sent and put into work is Colchester, where the company +has for some time had an installation at work, chiefly employing +incandescent lamps. The battery consists of lead electrodes, anode and +cathode being of the same character. They are constructed of narrow +ribbons of lead, each element being made from long lengths of the ribbon +about or nearly 0.20 in. width, rolled together into a flat cake like +rolls of narrow webbing, as illustrated by the annexed diagram, Fig. +1, the greater part of the ribbon being very thin and flat; but +intermediate thicker ribbons are also employed, as in Fig. 2, this +thicker ribbon being corrugated as shown, and affording passage room +for the circulation of the electrolyte. From four to eight coils of the +plain ribbons are between every pair of corrugated ribbons. They are +wound up together tightly, and pressed into the nearly rectangular form +shown. The bar for suspending the coil plates so made in the cells is +soldered to the coil. The object of this construction is of course to +obtain large lead surface, and of course a much larger surface is so +obtained than could be practically obtained from plain lead plates in +the same compass. A battery thus made may be seen at the offices of the +company, 110 Cannon Street. + +[Illustration: FIG. 1. FIG. 2.] + +A very ingenious device for cutting the battery out of circuit when +charged as much as is thought desirable is used by the company. In a +cell is an element which has a determined lower capacity than those in +the rest of the battery. Over this element is placed a gas-tight chamber +in which is a diaphgram, this diaphragm being of very flexible material +placed in the cover of the box of cells. When charging has proceeded as +long as is desirable, or proceeds too fast, hydrogen is evolved, and +this collecting in the chamber referred to acts upon the diaphragm, and +by means of a rod connected thereto, switches the current, which is +supplied to an electro-magnet and by which circuit is made through the +medium of mercury contacts. The object, of this is to save the +battery from destruction by over-charging or charging by too large a +current.--_The Engineer_. + + * * * * * + + + + +ACETYLENE FROM IODOFORM. + + +P. CAZENEUVE publishes in the _Comptes Rendus_ a new method for the +preparation of acetylene, which consists in mixing iodoform intimately +with moist and finely divided silver. An abundant evolution of acetylene +takes place without heating. The reaction is represented by the +following formula: 2CHI_{3} + 6Ag = C_{2}H_{2} + 6 AgI. The +decomposition of the iodoform is hastened if the silver is mixed with +finely divided copper, such as can be obtained by precipitating it from +its sulphate by means of zinc. + +Cazeneuve also observed that most metals which have any affinity for +iodine will decompose iodoform in the presence of water, forming +acetylene and an iodide of the metal. By the use of zinc he obtained a +liquid having a pleasant ethereal odor, and a gas mixture that contained +besides acetylene an iodine compound which burned with a purple-edged, +fawn-colored flame. + + * * * * * + + + + +WHEN DOES AN ELECTRICAL SHOCK BECOME FATAL? + + +In this age of electricity and electric wires carrying currents of +various intensity, the question of danger arising from contact with them +has caused considerable discussion. An examination into the facts as +they exist may therefore enlighten some who are at present in the dark. + +To begin with, we often hear the question asked--why is it that certain +wires carrying very large currents give very little shock, whereas +others, with very small currents, may prove fatal to those coming in +contact with them? The answer to this is--that the shock a person +experiences does not depend upon the current _flowing in the wires_, but +upon the current _diverted from them_ and _flowing through the body_. + +The muscular contraction due to a galvanic current, which was first +observed in the frog, gives a good illustration of the fact that it +requires only a very minute current to flow through the muscles in order +to contract them. Thus the simple contact of pieces of zinc and copper +with the nerves generated current sufficient to excite the muscles--a +current which would require a delicate galvanometer for its detection. +What is true of the muscles of the frog holds good also for the human +muscles; they too are very susceptible to the passage of a current. + +In order to determine the current which proves fatal we need only to +apply the formula which expresses Ohm's law, viz., C=E/R, or the current +(ampere) equals the electromotive force (volt) divided by the resistance +(ohm). + +According to the committee of Parliament investigation, the +electromotive force dangerous to life is about 300 volts; this then is +the quantity, E, in the formula. There remains now only to determine the +resistance in ohms which the body offers to the passage of the current. +In order to obtain this, a series of measurements under different +conditions were made. On account of the nature of the experiment a high +resistance Thomson reflecting galvanometer was used, with the following +results. + +When the hands had been wiped perfectly dry, the resistance of the body +was about 30,000 ohms; with the hands perspiring ordinarily it fell to +10,000 ohms; whereas when they were dripping wet it was as low as 7,000 +ohms. Our readers can judge this resistance best when we state that the +Atlantic cable offers a resistance of 8,000 ohms. + +Taking an ordinary condition of the body, with the hands perspiring as +usual, we would have the resistance equal to 10,000 ohms. Applying the +two known quantities in the formula, we get: + + C = (300 / 10,000) - (1 / 33.333+) + +This means, therefore, that when the electromotive force or potential is +great enough to send a current of 1/33 ampere through the body, fatal +results will ensue. This current is so minute that it would deposit only +about 6 _grains_ of copper in _one hour_, a grain being 1/7,000 of a +pound. + +Let us now compare these figures with some actual cases, taking as +an example a system of incandescent lighting. In these systems the +difference of potential between any two points of the circuit outside of +the lamps does not exceed 150 volts. Taking this figure, therefore, it +will be seen that under no circumstances can the shock received from +touching these wires become dangerous--not even by touching the +terminals of the dynamo itself; because in neither case can a current be +driven through the body, sufficient to cause an excessive contraction of +the muscles. + +In a system of arc lighting, however, we have to deal with entirely +different conditions; for, while in the incandescent system the adding +of a lamp, which diminishes the resistance, requires no increase of +electromotive force, the contrary is the case in the arc light system. +Here every additional lamp added to the circuit means an increase in +resistance, and consequent increase in electromotive force or potential. +Taking for example a well known system of arc lighting, we find that the +lamps require individually an electromotive force of 40 volts with a +current of 10 amperes. In other words, the difference in potential at +the two terminals of every such lamp is 40 volts. Consequently, if the +circuit were touched in two places, including between them only one +lamp, no injurious effects would ensue. If we touch the circuit so as +to include two lamps between us, the effect would be greater, since the +potential between those two points is 2 x 40 volts. We might continue +in this manner touching the circuit until we had included about 7 or +8 lamps, when the shock would become fatal, since the point would be +reached at which the difference of potential is great enough to send a +dangerous current through the body. + +Up to this point we have assumed that, while touching two points in the +wire, the rest of the circuit is perfectly insulated, so that no current +can leak, in other words, that the circuit is nowhere "grounded." If +this is not the case we may, under suitable conditions, receive a +shock by touching only _one_ point of the wire. This becomes clear +by considering the current to leak from another spot of different +potential, to pass through the ground and into the body; thus, on +touching the wire the body virtually makes a connection between the +two points of the circuit. In clear dry weather such leaks are +insignificant; but in damp and rainy weather, and with poor insulation, +they may rise to such a point at which it would be dangerous to touch +the circuit even with one hand, the leaks being sometimes so great as +to cause the lamps to burn in a fitful, desultory manner, and to go out +entirely. + +There is still another factor which enters into the discussion of the +danger of electric light wires. This must be looked for in the fact that +the physiological effects are greatest at the moment of the opening or +the closing of the circuit; or in a closed circuit they are the more +marked when the flow of current stops and starts, or diminishes and +increases. In dynamo electric machines the current is not absolutely +continuous or uniform, since the coils on the armature being separated a +distance cause a slight break or diminution of the current between each. +This break is so short that it does not interfere with the practical +work for lighting; in some constructions, nevertheless, the distances +apart is so great that, while not interfering with light, its effects +upon the muscles are greatly increased over those of other constructions +which give a more uniform current. + +All these statements might lead to the conclusion that arc light wires +are dangerous under any circumstances; but this is not the case. The +first and only requisite is, that they be perfectly insulated. When thus +protected accidents from them are impossible, and all mishaps that have +occurred through them can be traced directly to the lack of insulation. +Nevertheless, we would warn our readers against experimenting upon arc +wires by actual trial, because unforeseen conditions might lead to +disagreeable results. + + * * * * * + + + + +ROBERT CAUER'S STATUE OF LORELEI. + + +The statue of Lorelei, the mythical siren of the Rhine, represented in +the annexed cut, which is taken from the _Illustrirte Zeitung_, was +modeled by Robert Cauer, of Kreuglach on the Rhine. He was born at +Dresden in 1831, and is the son of the well-known sculptor Emil Cauer, +and a brother of the sculptor Karl Cauer. + +[Illustration: LORELEI STATUE BY ROBERT CAUER.] + + * * * * * + + + + +REDUCING AND ENLARGING PLASTER CASTS. + + +Ordinary casts taken in plaster vary somewhat, owing to the shrinkage of +the plaster; but it has hitherto not been possible to regulate this +so as to produce any desired change and yet preserve the proportions. +Hoeger, of Gmuend, has, however, recently devised an ingenious method +for making copies in any material, either reduced or enlarged, without +distortion. + +The original is first surrounded with a case or frame of sheet metal or +other suitable material, and a negative cast is taken with some elastic +material, if there are undercuts; the inventor uses agar-agar. The usual +negative or mould having been obtained as usual, he prepares a gelatine +mass resembling the hektograph mass, by soaking the gelatine first, then +melting it and adding enough of any inorganic powdered substance to give +it some stability. This is poured into the mould, which is previously +moistened with glycerine to prevent adhesion. When cold, the gelatine +cast is taken from the mould, and is, of course, the same size as the +original. If the copy is to be reduced, this gelatine cast is put in +strong alcohol and left entirely covered with it. It then begins to +shrink and contract with the greatest uniformity. When the desired +reduction has taken place, the cast is removed from its bath. From +this reduced copy a cast is taken as usual. As there is a limit to the +shrinkage of the gelatine cast, when a considerable reduction is desired +the operation is repeated by making a plaster mould from the reduced +copy, and from this a second gelatine cast is taken and likewise +immersed in alcohol and shrunk. It is claimed that even when repeated +there is no sacrifice of the sharpness of the original. + +When the copy is to be enlarged instead of reduced, the gelatine cast is +put in a cold water bath, instead of alcohol. After it has swollen as +much as it will, the plaster mould is made as before. For enlarging, +the mould could also be made of some slightly soluble mass, and then by +filling it with water the cavity would grow larger, but it would not +give so sharp a copy. + + * * * * * + + + + +STRIPPING THE FILM FROM GELATINE NEGATIVES. + + +We have frequent inquiries as to the best means of removing a +gelatino-bromide negative from its glass support so that it can be used +either as a direct or reversed negative, and it does not appear to be +very generally known that about two years ago Mr. Plener described a +method which answers well under all circumstances, whether a substratum +has been used or not. + +If a negative is immersed in extremely dilute hydrofluoric acid +contained in an ebonite dish, say half a teaspoonful to half a pint of +water, the film very soon becomes loosened, and floats off the glass, +this circumstance being due to the solvent action which the acid +exercises upon the surface of the plate as soon as it has penetrated the +film. If the floating film be now caught upon a plate which has been +slightly waxed, and it is allowed to dry on this plate, it will become +quite flat and free from wrinkles. To wax the plate, it should be held +before the fire until it is moderately hot, after which it is rubbed +over with a lump of wax, and the excess is polished off with a piece +of flannel. When the film is dry, it will leave the waxed glass +immediately, if one corner is lifted by means of a penknife. The film +will become somewhat enlarged during the above-described operation; but, +by taking suitable precautions, this enlargement may be avoided. It is +also convenient to prepare the hydrofluoric acid extemporaneously by the +action of sulphuric acid on fluoride of sodium; and, in many cases, it +is advisable to thicken up the film by an additional layer of gelatine. + +The following directions embody these points. The negative, which must +be unvarnished, is leveled, and covered with a layer of warm gelatine +solution (one in eight) about as thick as a sixpence. This done, and +the gelatine set, the plate is immersed in alcohol for a few minutes +in order to remove the greater part of the water from the gelatinous +stratum. The next step is to allow the plate to remain for five or six +minutes in a cold mixture of one part of sulphuric acid with twelve +parts of water, and in the mean time two parts of sodium fluoride are +dissolved in one hundred parts of water, an ebonite tray being used. A +volume of the dilute sulphuric acid equal to about one-fourth of the +fluoride solution is next added from the first dish, and the plate +is then transferred to the second dish, when the film soon becomes +liberated. When this is the case, it is placed once more in the dilute +sulphuric acid. After a few seconds it is rinsed in water, and laid on a +sheet of waxed glass, complete contact being established by means of a +squeegee, and the edges are clamped down by means of strips of wood held +in position by American clips or string. All excess of sulphuric acid +may now be removed by soaking the plate in methylated alcohol, after +which it is dried. It is as well to add a few drops of ammonia to the +last quantity of alcohol used. + +The plate bearing the film negative is now placed in a warm locality, +under which circumstances a few hours will suffice for the complete +drying of the pellicular negative, after which it may be detached +with the greatest ease by lifting the edges with the point of a +penknife.--_Photo. News_. + + * * * * * + + + + +NEW ANALOGY BETWEEN SOLIDS, LIQUIDS, AND GASES, + +By W. SPRING. + + +The author asks in the first place, What is the cause of the different +specific gravities of one and the same metal according as it has been +cast, rolled, drawn into wire, or hammered? Does the difference observed +prove a real condensation of the matter under the action of pressure, or +is it merely due to the expulsion by pressure of gases which have been +occluded when the ingot was cast? According to well-known researches, +metals such as platinum, gold, silver, and copper, which have +been proved to occlude gases on fusion, and to let them escape, +_incompletely_, on solidification, are precisely those which are +most increased in their specific gravity by pressure. The author has +submitted to pressures of about 20,000 atmospheres metals which possess +this property, either not at all, or to a very trifling extent, and he +finds that though a first pressure produces a slight permanent increase +of density, its repetition makes little difference. Their density is +found to have reached a maximum. Hence the density of solids, like that +of liquids, is only really modified by temperature. Pressure effects +no permanent condensation of solid bodies, except they are capable of +assuming an allotropic condition of greater density. The author's former +researches tend to show that solid matter, in suitable conditions of +temperature, takes the state corresponding to the volume which it is +compelled to occupy. Hence there is an analogy between the allotropic +states of certain solids and the different states of aggregation of +matter. Possibly the different forms of matter may be due to a single +cause--polymerization. The limit of elasticity of a solid body is the +critical moment when the matter begins to flow under the action of the +pressure to which it is submitted, just as, e.g., ice at or below 0 deg. may +be liquefied by strong pressure. A brittle body is simply one which does +not possess the property of flowing under the action of pressure. + + * * * * * + + + + +HYDROGEN AMALGAM. + + +Hydrogen, although a gas, is recognized by chemists as a metal, and when +combined with any solid metal--as in the case known to electricians as +the polarization of a negative element,--the compound may correctly be +termed an alloy; while any compound of hydrogen with the fluid metal +mercury may with equal correctness be termed an amalgam of hydrogen, or +"hydrogen amalgam." The efforts of many chemists and mining engineers +have for many years been devoted to a search for some effective and +economical means for preventing the "sickening" of mercury and its +consequent "flouring" and loss. Some sixteen or more years ago, +Professor Crookes, F.R.S., discovered and, after a series of +experiments, patented the use of an amalgam of the metal sodium for this +purpose. He made the amalgam in a concentrated form, and it was added +in various proportions to the mercury used for gold amalgamation. Water +becoming present, it will readily be understood that the sodium, in +being converted into the hydrate (KHO) of that metal, caused a rapid +evolution of hydrogen. The hydrogen thus evolved was the excess over a +certain proportion which enters into combination with the mercury. While +the mercury retained the charge of hydrogen, the "quickness" of the +fluid metal was preserved; but upon the loss of the hydrogen the +"quickness" ceased, and the mercury was acted upon by the injurious +components contained in the ore. + +Since the introduction of the sodium amalgam, many attempts have been +made, more especially in America, to overcome the tendency of mercury to +"sicken" and lose its "quickness." The greater number of these efforts +have been made by the use of electricity as the active agent in +attaining this end; but such efforts have been generally of a crude and +unscientific character. Latterly Mr. Barker, of the Electro-amalgamator +Company, Limited, has introduced a system--already detailed in these +pages--by which the mercury is "quickened." In his method the running +water passing over the tables, or other apparatus of a similar +character, is used as the electrolyte. In this arrangement, the mercury +being the cathode, plates or wires of copper constituting anodes are +brought into contact with the water passing over the mercury in each +"riffle." Both the cathode and the anodes are, of course, maintained in +contact with the poles of a suitable source of electrical supply. The +current then passes from the copper anode through the running water +to the mercury cathode, and so on to the negative pole of the +electro-motor. As a consequence of this arrangement, hydrogen is evolved +from the water, and has the effect of reducing any oxide or other +detrimental compound of the metal; in other words, it "quickens" and +prevents "sickening" of the fluid metal, and consequent "flouring" and +loss. While the hydrogen is evolved at the cathode, oxygen enters into +combination with the copper constituting the anodes. This to some extent +impairs the conductivity of the circuit. + +The latest process, however, is that of Mr. Bernard C. Molloy, M.P., +which we have already characterized as highly scientific and effective, +the production of a suitable amalgam being obtained under the most +economical and simple conditions. This process has the advantage of +producing not only a hydrogen amalgam, but also at will an amalgam of +hydrogen combined with any metal electro-positive to this latter. Thus +hydrogen potassium or hydrogen sodium can be obtained, as will be seen +by the following description. + +Mr. Molloy's effort appears to have been, in the first place, directed +to a system which could be adapted to any existing apparatus, and in +certain cases where water was scarce, to avoid altogether the use of +that, in some districts, rare commodity. For the purpose of explanation +we select an ordinary amalgamating table fitted with mercury riffles. +The surface of the table is in no way interfered with or disturbed. The +bed of the riffle, however, is constructed of some porous material, such +as leather, non-resinous wood, or cement, which serves as the diaphragm +upon which the mercury rests, and separates the fluid metal from the +electrolyte beneath. Running the full length of the table is a thin +layer of sand, supported and pressing against the diaphragm, and lying +in this sand is the anode, formed preferably of lead. A peroxide of +that metal is formed by the action of the currents, and may be readily +reduced for use over and over again after working for from one to three +months. The peroxide of lead, as is well known, is a conductor of +electricity, and this fact constitutes an important advantage in the +working of the process. The thin layer of sand is saturated with an +electrolyte, such as dilute sulphuric acid (H_{2}SO_{4} + 20H_{2}O) +to give a simple hydrogen amalgam; (Na_{2}SO_{4} + xH_{2}O) to give a +hydrogen sodium amalgam; or (K_{2}SO_{4} + xH_{2}O) to give a hydrogen +potassium amalgam. Numerous other electrolytes constituted by acids, +alkalies, and salts can be used to form an amalgam permanently +maintained in a condition of "quickness" and freed from all liability +to "sicken," whatever the components of the ore may be. The mercury +is connected with the negative pole of the voltaic battery or other +electro-motor, and the lead made with the positive pole of the same +source. When the current passes there is formed according to the nature +of the electrolyte, a hydrogen amalgam, or an amalgam of hydrogen with a +metal electro-positive to hydrogen. The electrolyte, which, it will be +understood, is distinct and apart from the body of water passing over +the table, will last almost indefinitely, there being no consumption of +any of its constituents, excepting hydrogen and oxygen from the water +of solution. The quantity of acid or saline material contained in the +electrolyte is so very small that there can be no difficulty in finding +a supply in any district. The question of the supply of electricity is +one which in many mining districts involves considerations of practical +importance, since a large supply would necessitate water or steam power. +It has been found that two cells having an electromotive force of about +two volts each will in this process suffice; if preferred, however, +a very small dynamo machine can be used. In connection with the +electro-motive force it is requisite to use, it may be observed that an +amalgam of sodium containing only a small quantity of this metal would, +when constituting a positive element in conjunction with a lead negative +and on an aqueous electrolyte, give an opposing electro-motive force of +less than three volts. Such an amalgam could therefore be obtained under +an electro-motive force of about four volts. The electrical resistance +in the circuit constituted by the apparatus being very small, no +electrical power is wasted. When water constitutes the electrolyte, as +in Barker's system, then the electro-motive force required to obtain a +given current would be very much greater than that above specified. +The conditions assured under this process appear to be all that can +be required, while the amalgams obtained are those most calculated to +preserve the "quickness" and prevent the "sickening" of the mercury. + +Mr. Molloy has designed a special form of amalgamating machine to be +used in conjunction with the above process, and with or without the aid +of water. By the employment of this machine, each particle of the ore +is slowly rolled in the quickened mercury for from fifteen to thirty or +more seconds. + +When the extent of the gold and silver mining industries is considered, +and when it is borne in mind that a considerable percentage of the +precious metal present in the ore is, in the ordinary process of +extraction, lost through defective amalgamation--due to insufficient +contact with the mercury or to a total absence of contact, as in the +case of float gold--it is obvious that the introduction of any system +obviating such loss is a matter of very great importance to those who +are interested in the above mentioned industries. We expect shortly to +hear of the practical introduction on a large scale of Mr. Molloy's +process, and we look forward with interest to the results which may be +obtained from it.--_The Engineer_. + + * * * * * + + + + +TREATMENT OF ORES BY ELECTROLYSIS. + +By M. KILIANI. + + +The author lays down general principles for electrolytic metallurgy. +Ores must be distinguished as good and bad conductors; the former +may serve directly as anodes, and are easily oxidized by the +electro-negative radicals formed at their contact, and dissolve readily +in the electrolyte. The bad conductors have to be placed in contact +with a conducting anode, formed of an inoxidizable substance, such as +platinum, manganese peroxide, or coke. In laboratory experiments a good +conducting ore is electrolyzed by suspension from a platinum wire in +connection with the source of electricity, and is then immersed in the +bath. On an industrial scale the ore, coarsely broken up, is placed in +one of the compartments of a trough divided by a diaphragm. + +On the fragments of the ore which extend up outside of the electrolytic +bath is laid a plate of copper connected with the positive wire. Care +must be taken that this plate does not plunge into the bath, otherwise +the current would not traverse the ore at all. The cathode is preferably +formed of the same metal which is to be obtained. The bath should +not contain organic acids. In practice the common mineral acids are +employed, or their salts, selecting by preference a salt of the metal +which is to be isolated. It is convenient to pass the current through +the greatest possible number of small decomposition troughs, taking care +that the resistance in each is not too great. With a current of one and +the same intensity we obtain in n troughs n times as much metal as in a +single one. To keep down the resistance of the circuit we employ poles +of a large surface, i.e., plenty of ore and baths which are as good +conductors as possible. + +The state in which the metal is deposited at the negative pole depends +on the secondary actions undergone by the electrolyte, and especially of +the escape of gas. This is a function of the _density_, of the current, +i.e., the proportion of its intensity to the surface of the cathode. If +the density is too great there is an escape of hydrogen, and the metal +is deposited in a spongy condition. If the density of the current falls +below a certain minimum, an oxide is deposited in place of metal. The +electrolytic treatment of ores often renders it possible to separate +the different metals which may be present. These are deposited in +succession, and are sharply separated if the electromotive power is not +too great. + +1. _Zinc_.--The zinciferous compounds--calamine, blende, and zinc +ash--are all poor conductors. They are first dissolved, and the salts +obtained are electrolyzed, employing anodes of coke. Blende should be +roasted before it is dissolved. The electrolytic bath should be as +concentrated as possible to avoid sponginess of the metal and an escape +of hydrogen. In a saturated solution the formation of hydrogen decreases +as the density of the current augments. + +2. _Lead_.--Galena is a good conductor, and may be directly +electrolyzed. The best bath is a solution of lead nitrate. The +arborescent crystallizations extend rapidly, and must be broken from +time to time to prevent the formation of a metallic connection between +the anode and the cathode. The sulphur of the galena falls to the bottom +of the bath, and may be separated from the gangue by solution in carbon +disulphide. + +3. _Copper_.--Native copper sulphide, though a good conductor, cannot +be directly electrolyzed en account of the presence of iron sulphide, +whence iron would be deposited along with the copper. The copper pyrites +are roasted, dissolved in dilute sulphuric acid, and the liquid thus +obtained is submitted to electrolysis. + + * * * * * + + + + +A PEOPLE WITHOUT CONSUMPTION, AND SOME ACCOUNT OF THEIR COUNTRY--THE +CUMBERLAND TABLELAND. + +By E. M. WIGHT, M.D., Chattanooga, Tenn., Late Professor of Diseases +of the Chest and State Medicine, Medical Department University of +Tennessee; Late Member of the Tennessee State Board of Health, and +ex-President of the Tennessee State Medical Society. + + +During the ten years that I have practiced medicine in the neighborhood +of the Cumberland Tablelands, I have often heard it said that the +people on the mountains never had consumption. Occasionally a traveling +newspaper correspondent from the North found his way down through the +Cumberlands, and wrote back filled with admiration for their grandeur, +their climate, their healthfulness, and almost invariably stated that +consumption was never known upon these mountains, excepting brought +there by some person foreign to the soil, who, if he came soon enough, +usually recovered. Similar information came to me in such a variety of +ways and number of instances, that I determined some four years ago, +when the attempt to get a State Board of Health organized was first +discussed by a few medical men of our State, that I would make an +investigation of this matter. These observations have extended over that +whole time, and have been made with great care and as much accuracy +as possible, and to my own astonishment and delight, I have become +convinced that pulmonary consumption does not exist among the people +native and resident to the Tablelands of the Cumberland Mountains. + +In the performance of the work which has enabled me to arrive at this +conclusion, I have had the generous assistance of more than twenty +physicians, who have been many years in practice in the vicinity of +these mountains. Their knowledge of the diseases which had occurred +there extended over a, period of more than forty years. Some of these +physicians have reported the knowledge of the occurrence of deaths from +consumption on the Tablelands, but when carefully inquired into they +have invariably found that the person dying was not a native of the +mountains, but, a sojourner in search of health. In answer to the +question: "How many cases of pulmonary consumption have you known to +occur on Walden's Ridge, among the people native to the mountains?" +eleven physicians say, "Not one." All of these have been engaged in +practice there more than three years, four of them more than ten years, +one of them more than twenty, and one of them more than forty years. All +the physicians of whom inquiries have been made are now residents, or +have been, of the valleys contiguous to Walden's Ridge, and know the +mountain people well. Four other physicians in answer to the same +question say, that they have known from one to four cases, numbering +eleven in all, but had not ascertained whether five of them were born +and raised on the mountains or not. The names and place of death of all +these cases were given, and I have traced their history and found that +but three of them were "natives," or had lived there more than five +years, and that one of these was 57 years of age when she died, and had +suffered from cancer for three years before her death. The two others +died within six months after returning home from long service in the +army, where both contracted their disease. + +All these investigations have been made with more particular reference +to that part of the Cumberlands known as Walden's Ridge than to the +mountains as a whole. This ridge is of equal elevation and of very +similar character to the main Cumberland range in the southern part of +Tennessee, northwest Georgia, and northwest Alabama, and what is true of +this particular part of the great Cumberland table is, in the main, true +of the remainder. + +Sequatchee Valley lies between Walden's Ridge and what is commonly known +in that neighborhood as the Cumberland Mountains, and separates it from +the main range for a distance of about one hundred miles, from the +Tennessee River below Chattanooga to Grassy Cove, well up toward the +center line of the State. Grassy Cove is a small basin valley, which +was described to me there as a "sag in the mountains," just above the +Sequatchee Valley proper. It is here that the Sequatchee River rises, +and flowing under the belt of hills which unites the ridge and the main +range, for two miles or more, rises again at the head of Sequatchee +Valley. Above Grassy Cove the mountains unite and hold their union +firmly on their way north as far as our State reaches. + +Topographically considered as a whole, the Cumberland range has its +southern terminus in Alabama, and its northern in Pennsylvania. It +is almost wholly composed of coal-bearing rocks, resting on Devonian +strata, which are visible in many places in the valleys. + +But a small portion of the Cumberland lies above a plane of 2,000 feet. +Walden's Ridge and Lookout Mountain vary in height from 2,000 to 2,500 +feet. + +North of Grassy Cove, after the ridges are united, the variation from +2,000 feet is but little throughout the remainder of the State, and +the general character of the table changes but little. The great and +important difference is in the climate, the winters being much more +severe in these mountains in the northern part of the State than in the +southern, and the summers much more liable to sudden changes of weather. +Scott, Fentress, and Morgan counties comprise this portion of the table, +and these have not been included in my examination, excepting as to +general features. + +In all our southern country, and I may say in our whole country, there +is no other large extent of elevated territory which offers mankind +a pleasant living place, a comfortable climate--none too cold or too +hot--and productive lands. We have east of the upper waters of the great +Tennessee River, in our State, and in North Carolina and Georgia, the +great Blue Ridge range of mountains, known as the Unaka, or Smoky, +Chilhowee, Great and Little Frog, Nantahala, etc., all belonging to the +same family of hills. This chain has the same general course as the +Cumberlands. It is a much bolder range of mountains, but it is vastly +less inhabitable, productive, or convenient of access. The winters there +are severely cold, and the nights in summer are too cold and damp for +health and comfort, as I know by personal experience of two summers on +Nantahala River. But the trout fishing is beyond comparison, and that +is one inducement of great value for a stout consumptive _who is a good +fellow_. These mountains are much more broken up into branches, peaks, +and spurs than the Cumberlands. They afford no table terrritory of +any extent. There are some excellent places there for hot summer +visits--Ashville, Warm Springs, Franklin, and others. + +The Cumberland Mountains, as a whole, are flat, in broad level spaces, +broken only by the "divides," or "gulfs," as they are called by the +inhabitants, where the streams flow out into the valleys. + +Walden's Ridge, of which we come now to speak particularly, is the best +located of any part of the Cumberlands as a place for living. From the +separation of this ridge from the main range of Grassy Cove to its +southern terminus at the Tennessee River, it maintains a remarkably +uniform character in every particular. From it access to commerce is +easy, having the Tennessee River and the new (now building) Cincinnati +Southern Railroad skirting its entire length on the east. It rises very +abruptly from both the Tennessee and Sequatchee Valleys, being from +1,200 to 1,500 feet higher than the valleys on each side. Looking from +below, on the Tennessee Valley side, the whole extent of the ridge +appears securely walled in at the top by a continuous perpendicular wall +of sandstone, from 100 to 200 feet high; and from the Sequatchee side +the appearance is very similar, excepting that the wall is not so +continuous, and of less height. + +The top of the ridge is one level stretch of plain, broken only by the +"gulfs" before mentioned and an occasional prominent sandstone wall or +bowlder. The width on top is, I should judge, 6 or 7 miles. The soil is +of uniform character, light, sandy, and less productive for the ordinary +crops of the Tennessee farmer than the soil of the lowlands. The grape, +apple, and potato grow to perfection, better than in the valleys, and +are all never failing crops; so with rye and buckwheat. Corn grows +well, very well in selected spots, and where the land is made rich +by cultivation. The grasses are rich and luxuriant, even in the wild +forests, and when cultivated, the appearance is that of the rich farms +of the Ohio or Connecticut Rivers, only here they are green and growing +the greater part of the year; so much so that sheep, and in the mild +winters the young cattle, live by the wild grasses of the forests the +whole year. The great stock raisers of the Sequatchee and Tennessee +Valleys make this the summer pasture for their cattle, and drive them to +their own farms and barns or to market in winter. The whole Cumberland +table, with the exception of that small part which is under cultivation, +is one great free, open pasture for all the cattle of the valleys. +Thousands of cattle graze there whose owners never pay a dollar for +pasturage or own an acre of the range, though, as a rule, most of the +well-to-do stock farmers in the valleys own more or less mountain lands. +These lands have, until quite recently, been begging purchasers at from +121/2 to 25 cents per acre in large tracts of 10,000 acres and upward, and +perhaps the same could be said of the present time, leaving out choice +tracts and easily accessible places, which are held at from 50 cents to +$2 per acre, wooded virgin lands. + +The forest growth of Walden's Ridge is almost entirely oak and chestnut. +Hickory, perhaps, comes next in frequency, and pine after. There is but +little undergrowth, and where the forests have never been molested there +are but few small trees. This is due to the annual fires which occur +every autumn, or some time in winter, almost without exception, and +overrun the whole ridge. It does not rage like a prairie fire. Its +progress is usually slow, the material consumed being only the dry +forest leaves and grasses. The one thing essential to its progress is +these dry leaves, hence it cannot march into the clearings. Nearly all +the small shrubs are killed by these fires, otherwise they are harmless, +and are greatly valued by the stock men for the help they render in the +growth of the wild grasses. The free circulation of air through these +great unbroken forests is certainly much facilitated by these fires, +since they destroy every year what would soon become impediments. The +destruction of this undergrowth leaves the woods open, and the lands are +mainly so level that a carriage may be driven for miles, regardless of +roads, through the forests in every direction. + +The shrubs about the fields and places where the forests have +been interrupted by civilization and other causes are blackberry, +huckleberry, raspberry, sumac, and their usual neighbors, with the +azalia, laurel, and rhododendron on the slopes and in the shade of the +cliffs. + +The kinds of wild grasses, I regret to say, I have not noted, and the +same of the rich and varied display of wild flowers. + +The whole ridge is well supplied with clean, soft running water, even +in the driest of the season. There are no marshes, swamps, or bogs, no +still water--not even a "puddle" for long--for the soil is of such a +character, that surface water quickly filters away into the sands and +mingles with the streams in the gulfs. Springs of mineral water are +abundant everywhere. Probably there is not a square mile of Walden's +Ridge which does not furnish chalybeate water abundantly. Sulphur +springs with Epsom salts in combination are nearly as common. + +The entire extent of Walden's Ridge is underlaid with veins of coal, and +iron ore is plentiful, especially in the foot hills. The coal and iron +are successfully mined in many places on the eastern slope; on the +western they are nearly untouched for the want of transportation. I find +that the impression prevails that the minerals of the Cumberlands are +largely controlled by land agents and speculators. This is only true as +applied to a very small part of the whole, not more than 1 per cent. The +mineral ownership remains with the lands almost entirely. + +The prevailing winds on Walden's Ridge are from the southwest; northers +and northeasters are of rare occurrence. One old lady who had resided +there for forty years, in answer to my query upon this subject, said: +"Nine days out of ten, the year round, I can smell Alabama in the air." +This was the usual testimony of the residents. Winds of great velocity +never occur there. In summer there is always an evening breeze, +commencing at 4 to 6 o'clock, and continuing until after sunrise +the next morning. In times of rain, clouds hang low over the ridge +occasionally, but they never have fogs there. + +The range of the thermometer is less on the Tablelands than in the +adjacent valleys. I have had access to the carefully taken observations +of the Lookout Mountain Educational Institute, such published accounts +as have been made by Professor Safford, State Geologist, Mr. Killebrew, +the thorough and painstaking private record of Captain John P. Long, +of Chattanooga, and many more of less length of time. From all these I +deduce the fact that the summer days are seven or eight degrees cooler +on the mountains than in the Tennessee Valley at Chattanooga, and five +or six degrees cooler than in the Sequatchee Valley, as far up as Dunlay +and Pikeville. The nights on the table are cooler than in the lower +lands by several more degrees than the days; how much I have thus far +not been able to state. The late fall months, the winter, and early +spring are not so much colder than the valleys as the summer months, the +difference between the average temperature of the mountains and valleys +being at that time four or five degrees less than in the summer. There +is no record of so hot a day ever having occurred on the Cumberladd +Mountains as to cause mercury to run so high as 95 deg. F., or so cold a day +as to cause it to run so low as 10 deg. below zero. + +In the average winter the ground rarely freezes to a greater depth than +2 or 3 inches, and it remains frozen but a few days at a time. Ice has +been known to form 8 inches thick, but in ordinary winters, 3 or 4 +is the maximum. Snow falls every winter, more or less, and sometimes +remains for a week. Old people have a remembrance of a foot of snow +which lasted for a week. + +Walden's Ridge has a total population of a little more than 4,000, +scattered over 600 square miles of surface. The number of dwellings is +about 800. Ninety per cent. of these are log houses; 70 per cent. of +them are without glass windows; light being furnished through the +doorways, always open in the daytime, the shuttered window openings, and +the open spaces between the logs of the walls. Less than 2 per cent. of +these houses have plastered walls or ceilings, and less than 5 per cent. +have ceiled walls or ceilings. About 20 per cent. of them are fairly +well chinked with clay between the logs, the remainder being but +indifferently built in that particular. Fully 90 per cent. of these +abodes admit of free access of air at all times of day and night, +through the floors beneath as well as the walls and roof above. It is +the custom of the people to guard against the coldest of days and nights +by hanging bed clothes against the walls, and many good housewives have +a supply of tidy drapery which they keep alone for this purpose. + +Wood, always at hand, is the only fuel in use. The whole heating +apparatus consists in one large open fireplace, built of stone, +communicating with a large chimney outside the house at one end, and +frequently scarcely as high as the one story building which supports it. +This chimney is constructed in such a manner as to be a great ventilator +of the whole room, quite sufficient, it would be thought, if there were +no other means of ventilation. It is usually made of stone at the +base, and that part above the fire is of sticks laid upon one another, +cobhouse fashion, and plastered over inside and between with similar +clay as that with which the house walls are chinked. + +Very few of these houses are more than one story high. They are all +covered with long split oak shingles--the people there call them +"boards"--rifted from the trunks of selected trees. There is no +sheathing on the roof beneath these shingles. They are nailed down upon +the flat hewn poles running across the rafters, at convenient distances. +Looking up through the many openings in the roof in one of these house, +one would think that this would be but poor protection against rain, but +they rarely leak. + +Not one family in fifty is provided with a cooking stove. They bake +their bread in flat iron kettles, with iron covers, covered with hot +coals and ashes. These they call ovens. The meat is fried, with only the +exception of when accompanied by "turnip greens." + +The question, "What is the principal food of the people who live on +these mountains?" has been asked by me several hundred times. The +almost invariable answer has been, "Corn bread, bacon, and coffee." +Occasionally biscuits and game have been mentioned in the answers. All +food is eaten hot. Coffee is usually an accompaniment of all three +meals, and is drunk without cream and often without sugar. Some families +eat beef and mutton for one or two of the colder months in the year on +rare occasions, though beef is commonly considered "onfit to go +upon," as I was told upon several occasions, and mutton sustains less +reputation. Chickens are used for food while they are young and tender +enough to fry, on occasions of quarterly meetings, visits of "kinfolks" +or the "preachers" and the traveling doctors. Fat young lambs are plenty +in many settlements from March to October, and can be had at fifty cents +each, but I could not learn that one was ever eaten. + +A large majority of the adult population use tobacco in some shape--the +men by chewing or smoking, the women by smoking or dipping snuff. They +never have dyspepsia, nor do they ever get flesh, after they pass out of +childhood, though nearly all the children are ruddy in appearance, and +well rounded with fat. + +One physical type prevails among the people in middle life, and carries +along into old age but little change; and old age is common there. +Nearly every house has its old man or old woman, or both. Everybody, +father and mother, and frequently grandfather and grandmother, is still +on hand, looking as brisk and moving about as lively as the newer +generations. After they pass their forty years, they never seem to +grow any older for the next twenty or thirty, and the grandfathers and +grandmothers can scarcely be selected, by comparison, from their own +children and grandchildren. The men are taller than the average, and +the women, relatively, taller than the men. They are all thin featured, +bright eyed, long haired, sharp looking people, with every appearance of +strength and power of endurance. + +I think the men who live on Walden's Ridge can safely challenge the +world as walkers--aborigines and all; and unless the challenge should be +accepted by their own women folks, I feel quite sure they would "win the +boots." They go everywhere on foot, and never seem to tire. + +Nearly all the people of the Tablelands are employed in the pursuits of +agriculture. Very few of them seem to be hard workers. The men are all +great lovers of the forest sports, much given to the good, reliable, old +fashioned long rifles. The women and children are much employed in out +door occupations, and live a great portion of their time in the open +air. The clothing of all classes is scanty. The use of woolen fabrics +for underwear has not yet been introduced, and coarse cotton domestic +is the universal shirting, and cotton jeans, or cotton and wool mixed, +constitute the staple for outer wearing apparel. The men wear shoes +throughout the year much more commonly than boots. They never wear +gloves, mittens, scarfs, or overcoats, and they scorn umbrellas. +Probably this whole 4,000 people do not possess two dozen umbrellas or +twice as many overcoats. The women go about home with bare feet a great +part of the summer. They never wear corsets or other lacing. + +I have learned by careful inquiry that very few of the people of the +Ridge have ever had the diseases of childhood. Scarlet fever I could +hear of in but two places, and I suppose that not one person in fifty +has had it. Whooping cough and measles have occurred but rarely, and the +large majority have not yet experienced the realities of either. Very +few people there have ever been vaccinated, nor has smallpox ever +prevailed. Typhoid, typhus, and intermittent fevers are unknown. In the +great rage of typhoid fever which took place ten or twelve years ago in +the Tennessee and Sequatchee Valleys, not a single case occurred on the +Mountains, as I have been informed by physicians who were engaged in +practice in the neighborhood at the time. Diphtheria has never found a +victim there; so of croup. Nobody has nasal catarrh there, and a cough +or a cold is exceedingly rare. + +I have said that these observations refer more particularly to Walden's +Ridge than to the Cumberland Tablelands in our State as a whole. This +ridge was chosen by me for this examination, mainly for the reason of +its convenience, but partly owing to its being more generally settled +than any other equal portion of the table which lies in Tennessee. +Lookout Mountain is not as well located; it is on the wrong side of the +Tennessee River, and but a few acres of it belong in this State. Sand +Mountain is altogether out of the State, but it is perhaps nearer like +Walden's Ridge in its physical features than Lookout. That part of the +Cumberlands west of Sequatchee Valley is Walden's Ridge in duplicate, +excepting that it is further west, and nearer the Middle Tennessee +basin. There are some small towns, villages of miners, and summer +resorts there, which interferes with that evenness of the distribution +of population which Walden's Ridge has, rendering it more liable to +visitations of epidemic and contagious diseases. The tablelands north +of the center line of the State, above Grassy Cove, are very similar +to Walden's Ridge, as far up as Kentucky, with the exception before +mentioned--that of climate--it being from one to ten degrees colder in +winter. + +This whole Cumberland Table is no small country. It comprises territory +enough to make a good sized State. At present, it is almost one great +wilderness, in many particulars as unknown as the Black Hills. It is +coming into the world now, and will be well known in a few years. The +great city of Cincinnati has determined to build a railroad through +the very center of this great table in the north part of the State, +connecting with Chattanooga in the southern part. This road is nearly +bored through, and in another year or two the Cumberland Tablelands in +Tennessee will be much heard of at home and abroad. + +It seems to me this country has merits. It is located in the latitude of +mild climate; not so far south as to be scorched by the hot summer sun, +or visited by the great life destroying epidemics; not so far north as +to meet the severe and lengthened winters. + +Climate, we know, is a fixture; it has a government; it has rules; the +weather may change, but climate does not; it is a permanent out-door +affair, and what is true of to-day was true centuries ago, and will +be true forever, in the measure of any practical scope, at least. The +people of the world are beginning to know that the greatest destroyer of +human life has its remedy in climate. + +Mr. Lombard, in his famous exhibit in relation to the prevalence of +consumption among the people of different occupations, circumstances of +life, and place of dwelling, gives the lowest number of deaths from this +cause to those who live in the open air. He found the people who lived +most in the open air, as would be readily conjectured, in the mild +latitudes, not in the countries of hot sands or cold snows. + +[The above article, in regard to which we have noticed frequent +allusions in many of our exchanges, all erroneously attributing it to +_Dr. Wright_, of Tennessee, and for which we have received repeated +requests quite recently, was read by the lamented Dr. E.M. Wight at +the 43d annual meeting of the Tennessee State Medical Society, held +at Nashville, April 4, 5, and 6, 1876. Its distinguished and talented +author will long be remembered as one of the most active, earnest, and +zealous members of the State Society. At this meeting he also read a +very admirable paper on "The Microscopic Appearance of the Blood in +Syphilis," and prepared the report of the Committee on State Board +of Health, to which report may be ascribed the honor of securing the +necessary legislation organizing the Board. A true, upright, honest man, +an earnest, devoted and zealous physician, universally esteemed and +beloved by all who knew him; himself the subject of tuberculosis, dying +in the prime of a brilliant manhood. He had but few equals in the +glorious profession he honored and loved so well. + +From a careful reading of his paper, we find that he describes a large +area of territory, free, absolutely free, from subsoil moisture, a +climate mild and equable, a soil capable of producing nearly everything +necessary for the comfortable maintenance of human life, surroundings +that tempt, nay, compel the greatest possible amount of open air +life. His description is exceedingly accurate of a plain, primitive, +simple-minded people with but few wants, many of the virtues and few +of the vices of humanity. With their surroundings, soil, climate, +residence, and mode of living, need we be surprised that "there is +a people," or a land "free from consumption"?--ED.]--_Southern +Practitioner_. + + * * * * * + + + + +THE TREATMENT OF HABITUAL CONSTIPATION. + + +Dr. F.P. Atkinson thus writes in the _Practitioner_, January, 1884: I +suppose there is no derangement of the system we are more frequently +called upon to treat than habitual constipation; and though all kinds of +medicines are suggested for its relief, they rarely produce more than +temporary benefit--and it is difficult to see how the result can well be +otherwise, while the root of the evil remains untouched. Now by far the +more numerous subjects of this disorder are women; and as they do not +seem to know that regularity is essential to the performance of every +one of nature's operations, they appoint no stated times for trying to +get the bowels relieved, but trust to receiving intimation when the +rectal accumulation and distension can be borne no longer. This method +of action may and does answer fairly well for a time; but nature +gradually gets upset, the sensation of the lower bowel becomes blunted, +and at last it ceases to respond to the ordinary stimulus. Then +aperients are regularly resorted to, and although these act fairly +well for a time, they gradually have to be increased in strength +and frequency. Now, as regards the treatment, the first thing to be +accomplished is of course to get the rectum well relieved; the next, +to get the actions to take place at fixed times; and lastly, it is +necessary to get more tone imparted to the muscular tissue of the +bowels, so that the regularity of action may be helped and also +maintained. In order, then, to get the bowels relieved in the first +instance, it is well to give five grains of both compound colocynth and +compound rhubarb pill at bed-time (this rarely requires to be repeated), +then to take a tumblerful of cold water the next morning on waking, and +repeat it regularly at the same time each day. Should the bowels remain +sluggish for some time, the same quantity of water may be taken daily +before each meal. Supposing no action takes place on rising or shortly +after, a small injection of warm water may be resorted to. After each +movement of the bowels, a small hand-ball syringeful of _cold_ water +should be thrown into the rectum and retained. A soup plateful of coarse +oatmeal porridge (made with water and taken according to the Scotch +method, viz., by filling half the spoon with the hot porridge and the +other with cold milk) each night at bed-time, or even every night and +morning for a time, is often a very great help. But above all things, +it is necessary for the patient to _try_ and get relief at a certain +_fixed_ time regularly every day. If these directions are strictly +carried out in their entirety, the evil, even if it has been of long +standing, will generally be corrected, and the patient will improve in +health and appearance. Of course where the constipation results from +exhaustion of the nervous system (such, for instance, as is brought +about by self-abuse), the special cause has to be taken into +consideration, and such treatment adopted as is suited to the particular +necessities of the case. + + * * * * * + + + + +THE PYRAMIDS OF MEROE. + + +About fifty miles from the mouth of the Atbara, and, of course, on the +eastern bank of the Nile, stand the pyramids of Meroe. They consist +of three groups, and there are, in all, about eighty pyramids. The +presumption is that they represent the old sepulchers of the kings of +Meroe. Candance, Queen of the Ethiopians, mentioned in Acts, chap. +viii., v. 27, is supposed to have belonged to Meroe, that being the name +also of the capital, which is understood to have been somewhere not far +distant from the sepulchers. These pyramids of Meroe possess one marked +feature, distinguishing them from the pyramids of Egypt proper--that is, +they have an external doorway or porch. As there is no entrance to the +pyramid at these porticoes, it is quite possible that they were temples +for worship or making offerings to the dead. By comparing them with +the pyramids of Ghizeh, it will be seen that they are also taller in +proportion to their base. Another important point in these porches +or temples is the existence of the arch; and that, too, an arch in +principle, with a keystone.--_Illustrated London News_. + +[Illustration: THE PYRAMIDS OF MEROE, ON THE NILE.] + + * * * * * + + + + +THE PROLIFICNESS OF THE OYSTER. + + +In an article by Prof. Karl Mobius on "The Oyster and Oyster Culture," +reproduced in the recently issued report of the U. S. Commissioner of +Fish and Fisheries, the author says: + +A mature egg-bearing oyster lays about one million of eggs, so that +during the breeding season there are upon our oyster beds at least +2,200,000,000,000 young oysters, which surely would suffice to transform +the entire extent of the sea-flats into an unbroken oyster bed; for if +such a number of young oysters should be distributed over a surface 74 +kilometers long by 22 broad, 1,351 oysters would be allotted to every +square meter. But this sum of 2,200,000,000,000 young oysters is +undoubtedly less than that in reality hatched out, for not only do those +full-grown oysters which are over six years of age spawn, but they begin +to propagate during their second or third year, although it is true that +the young ones have fewer eggs than those which are fully developed. At +a very moderate estimation, the total number of three to six year old +oysters which lie upon our beds will produce three hundred billions of +eggs. This number added to that produced by the five millions of full +grown oysters would give for every square meter of surface not merely +1,351 young oysters, but at least 1,535. In order to determine how +many eggs oysters produce, they must be examined during their spawning +season. This begins upon the Schleswig-Holstein beds in the middle of +June, and lasts until the end of August or beginning of September. The +spawning oyster does not allow its ripe eggs to fall into the water, as +do many other mollusks, but retains them in the so-called beard, the +mantle, and gill-plates until they become little swimming animals. The +eggs are white, and cover the mantle and gill-plates as a semi-fluid, +cream-like mass. As soon as they leave the generative organs the +development of the germ begins. The entire yolk-mass of the egg divides +into cells, and these cells form a hollow, sphere-like body, in which an +intestinal canal arises by the invagination of one side. Very soon the +beginnings of the shell appear along the right and left sides of the +back of the embryo, and not long afterward a ciliated pad, the velum, is +formed along the under side. This velum can be thrust out from between +the valves of the shell at the will of the young animal, and used by the +motion of its cilia as an organ for driving food to the mouth, or +in swimming as a rudder. During these transformations the original +cream-white color of the germ changes into pale gray, and finally into a +deep bluish-gray color. At this time they have a long oval outline, and +are from 0.15 to 0.18 of a millimeter in breadth. Over 300,000 can find +room upon a square centimeter of surface. If an oyster in which the +embryos are in this condition is opened, there will be found upon its +beard a slimy coating thickly loaded with grayish-blue granules. These +granules are the embryo oysters, if a drop of the granular slime be +placed in a dish with pure sea water, the young animals will soon +separate from the mass, and spread swimming through the entire water. +When the embryos are at this stage their number may be estimated in the +following manner: The whole mass of embryos is carefully scraped from +the beard of the mother oyster by means of a small hair brush. The whole +mass is then weighed, and afterward a small portion of the mass. This +small portion is then diluted with water or spirits of wine, and the +embryos portioned out into a number of small glass dishes, so that they +can be placed under the microscope and counted. Thus, knowing the weight +of the small portion and the number of embryos in it by count, we can +estimate the total number of embryos from the weight of the entire mass, +which is also known. In this manner I estimated the number of embryos +in each of five full grown Schleswig-Holstein oysters caught in August, +1869, and found that the average number was 1,012,956. + +Notwithstanding this great fecundity, but an extremely small proportion +of the young oysters produced during the course of the summer arrive +at maturity, 421 only out of 500,000,000 escaping destruction. The +immolation of a vast number of young germs is the means by which nature +secures to a few germs the certainty of arriving at maturity. In order +to render the ideas of germ-fecundity and productiveness more easily +understood, Prof. Mobius makes the following comparison between the +oyster and man: + +According to Wappaus, for every 1,000 men there are 347 births. +According to Bockh, out of every 1,000 men born 554 arrive at maturity, +that is, live to be twenty years or more of age; thus, on an average, +347 children are produced from 554 mature men, or 626 children from +1,000 mature men. Since 1,000 full-grown oysters produce 440,000,000 of +germs, then the germ fecundity of the oyster is to the germ fecundity of +man as 440,000,000 to 6.26, or as 7,028,754 to 1. On the other hand, the +number which arrive at maturity is 579,002 times as great with mankind +as with the oyster; for of 1,000 human embryos brought into the world +554 arrive at maturity, or of 440,000,000 newly born 243,760,000 would +live to grow up, while of 440,000,000 young oysters only 421 ever become +capable of propagating their species. The proportion is then 421 to +243,760,000, or as 1 to 579,002. I am fully persuaded that these figures +represent the number of oysters which arrive at maturity more favorably +than is really the case, since from every thousand of full grown oysters +it is certain that, on an average, more than 440,000,000 young are +produced. + + * * * * * + + + + +RED SKY. + + +The beautiful red sky which has been so frequent of late, morning as +well as evening, has excited much comment. The comment, however, has +consisted more of description, statement of fact, theory, and wonder as +to cause, rather than as to satisfactory explanation. + +Facts in the case which would reveal the secret of this beautiful +display of nature are not complete and numerous enough at present to +establish the cause of this phenomenon on a sure basis; yet enough +facts, it would seem, have been obtained to satisfy the strong mind +capable of bridging over a wide expanse. + +Facts in an argument are like piers to a bridge-the more we have of +them, c. p., the more substantial the structure. When the facts are +_legion_, the structure becomes a causeway, and there is no need of +argument. + +Argument is a bridge--the fewer the facts, the more the necessity for +the bridge; the less the facts, the more argument necessary to connect +the few we have, and the more skill is required to make substantial +connecting links between the few solid piers (facts) that exist. + +One of the queer things in connection with this is, the public have +looked chiefly, if not wholly, to the astronomers for an explanation +of this phenomenon, when it is not their special province to explain +matters in this department of nature. + +The explanation belongs to the department of meteorology, and not to +astronomy. But the fact of having looked to the astronomers shows how +little the world knows of meteorology and how few meteorologists +there are able, ready, and willing to rise and explain in face of the +opposition of the public, who seem to think that the explanation must +necessarily belong to astronomy. Astronomy proper deals with the +position of the earth in space and its relation to the other heavenly +bodies, whether suns, fixed stars, planets, satellites, comets, or other +bodies in the vast space about us. Meteorology deals with the atmosphere +of the globe, in all its forms. Astronomy could be studied in the early +ages; its grand facts were not wholly dependent upon the advanced +condition of the mechanic arts; it could be studied even without the aid +of telescopes, though telescopes have added much to its advancement. +Meteorology, on the contrary, depended on the advancement of the arts +and sciences; they must first be perfected ere we could know much about +this branch of science. To one unfamiliar with the advancement and +perfection of meteorology within the past ten years, this statement +may seem strange, yet it is an undisputable fact that, prior to the +establishment of the daily weather reports, the knowledge on this +subject amounted to very little, and was not even worthy of being +designated a science. Prior to the advent of the weather map the world +was in absolute ignorance of the laws governing the atmosphere. Sure, we +had had large volumes on the laws of storms, but the later revelations +leave them shelved high and dry on the shores and as useless as a wreck +in a similar condition; with the daily weather map before us we have no +need to even open these huge volumes; they are completely circumvented, +and only negative in value--to show how little was known of the subject +without the full and complete facts daily collected and spread before us +on the map published by the Weather Bureau. + +In order to understand the color of our sky, we must understand the +subject which is so immediately connected with it and its creation. + +The earth is a sphere in space; generally speaking, it is composed of +land and water. These are two factors; the heat that it derives from +the sun forms a third factor; the three--land, water, and heat--are +essential to life, at least the higher conditions of life which +culminate in man. The old physical geography taught us this much, but +it was not able to go further and tell us why it was cold or warm +independent of the seasons; it could not explain why it was at times as +warm, and even warmer, half-way to the pole than at the equator; why it +was at times very warm in the extreme northeast while very cold in +the Southern States; cold in the northwest when it was warm in the +northeast, and warm in the northwest when cold all along the upper +Atlantic seaboard; it could not forewarn us of storms. These and a +host of other facts, which the weather map makes as plain as astronomy +demonstrates that Jupiter is a planet, the new revelation, through the +instrumentality of the perfected telegraph system, makes exceedingly +plain to us if we will but seek the easily obtained information. + +The principal revelations of the weather map are the facts in regard to +the areas of high and low barometer, and the influence they exert upon +the climate of the globe. + +These conditions--high and low barometer--move on general lines from the +west towards the east, or towards the rising sun, and around the world +in irregular belts. The centers of low barometer are various distances +apart, from a thousand to two thousand and even more miles apart--call +the average about two thousand miles. + +The clouds are formed from the moisture present by the action of the +sun's heat. The direction of the wind is from the area of high barometer +to that of low. The nearer the winds approach the center of "low" (low +barometer), the more they partake of the lines of the volute curve, or +curve of the sea shell or water in a whirlpool. High barometer is the +atmospheric hill; low barometer is the atmospheric valley. But time at +present will not permit more than these general statements; a close +study of the weather map for a season will reveal the beautiful minor +details. + +To the reader it may seem a long way round, yet in order to fully +understand the nature of the atmosphere which surrounds our globe we +must pay due attention to these newly discovered physical laws. + +The red sky which was so noticeable, in the fall of 1883, the +astronomers have told us was due to "meteoric dust" which was produced +by the volcanic eruption on the island of Java, August 27, 1883. + +This "meteoric dust" they say combined with the atmosphere, followed it +around the earth, and caused the beautiful redness of the sky at morning +and evening. For one, I do not believe dust of any description in the +atmosphere would produce such an effect. + +There is nothing luminous, transparent, or delicate about dust. Dust +would not remain in the atmosphere for months, it would settle in a very +short time, and if thick enough in the atmosphere to obstruct the light +of the sun it would be visible, discernible, to the eye, and manifest +on the face of nature. Years ago, before the age of the weather map, we +might have thought that the atmosphere followed the surface of the earth +like the water on a grindstone, but it does not. As already seen, the +wind is from the area of high barometer to that of low, and there are +many of these "low centers." + +From the best calculation we can make at present, there would be at +least some six centers on an average between the center of the United +States and the island of Java. In addition to this there would also be +a number of belts of "low" centers, which would complicate the thing +threefold at least. At all these different centers the winds would be +blowing from all points of the compass at the same time. Such winds +would not be apt to bring the "meteoric dust" from Java to the United +States, either in an easterly or westerly direction. But, it is said, +"dust" has been gathered. + +How high from the surface of the ground has this _dust_ been +gathered--at what elevation? + +There is undoubtedly a little dust in the air most of the time, but I do +not think that it extends very high. Where it would be the highest and +most perceptible would be on the arid plans of Africa and Asia, when +the _simoom_ is passing, or in the track of a tornado. But from the +multiplicity of these storm centers and the varied winds they would +produce even this dust could not travel from Java to America. + +Again, all clouds, no matter how high or how low, are affected by the +low centers, as the movement of clouds prove, and travel from the "high" +to the "low," from and to all points of the compass. High authority +gives the heights of the clouds as follows: lower clouds, 16,000 feet; +upper clouds, 23,000 feet. + +As all clouds, from the highest to the lowest, are affected by the +centers as above referred to, it follows that if this "meteoric dust" +follows the earth around, as it would have to do in order to make good +this theory, it would have to travel suspended in the atmosphere above +the upper clouds, or at a height of more than 23,000 feet, or at an +elevation of over four miles! + +Now, is it reasonable to believe that dust, however fine, will remain in +the atmosphere at that elevation for over six months? + +As a side argument it is suggested that the smoke of the burning woods, +or few years ago in Michigan, caused as peculiar condition of the +atmosphere. This extensive fire was on a day when the area of low +barometer was on a high line of latitude and passing to the eastward. +This naturally took the smoke, which is far lighter than dust, along +with it. It mingled with the muggy condition of an extensive "low," and +produced a yellowness of the atmosphere. This however was of only a few +hours' duration, and was only visible in favorable localities. + +Here again we see the advantage of the weather maps; but for this map we +would never have been able to have satisfactorily explained the peculiar +phenomenon produced by the great Michigan fire. + +If the delicate redness of the sky is not caused by dust, what is it +caused by? + +But for the weather map, I think we should still be in the dark in +regard to it. + +In the first place, this redness is nothing new, only the conditions +are more favorable sometimes than at others. It has always existed and +always will exist, independent of earthquakes, volcanoes, etc. Nature +is ever changing; the movements of the atmosphere more resemble the +kaleidoscope than any thing else. + +The summer and fall of 1883, the movements of "high" (high barometer) +over the United States were quite central and extensive, causing this +peculiar phenomenon over a wide extent of territory. + +We have no information of the condition of the barometer over the other +part of the world; we speak move particularly of the United States; yet +if certain conditions produce certain effects here, it is quite safe to +say that the same effects are produced by the same cause elsewhere. + +As now well established by the map, the surface wind is from the area +of high barometer to that of low--from the atmospheric hill to the +atmospheric valley. + +The tendency of this is to free "high" of all clouds and moisture; but +then it is impossible to free "high" entirely of moisture; a little +will remain, and it is just this little, which is highly rarefied, that +produces the result. We look around us and above, we see little or no +evidence of evaporation, yet it is the while going on. When the sun is +immediately below the horizon, where it will shine horizontally through +the mass of light, suspended moisture, the delicate presence of vapor +heretofore unnoticed is revealed. The action of the sun's rays is the +same as when illuminating a well formed cloud--it is an embodiment +of the same principle, but the material is much more expanded. The +particles of suspended moisture are very fine, few and far between, +therefore the effect of the light upon it is more diffused and +transparent. It is much like looking through a piece of window glass +flatwise and endwise; flatwise we do not perceive any color; endwise, +from seeing through a greater mass, the glass has a very perceptible +green color. + +We see the same idea also in the rising and setting sun and moon. On +a clear, cloudless night, when nothing seems to interfere with the +brightness of the stars, we cannot, by looking upward, perceive any +moisture present in the atmosphere; but if we cast our eyes to the +horizon, whereby we see through the mass of atmosphere endwise, as it +were, and note the appearance of the stars there, or the rising or +setting moon, we will see that the atmosphere there gives a redness +to the rising body, which it does not have when it has ascended to +mid-heaven. On a clear night, which is caused by the presence of the +area of high barometer, the moon when in mid-heaven is of a clear, +silver-white, and it is the same moon that at the horizon was a deep +red. The color of the moon has not changed; it is simply the medium +through which it is seen that produces the difference in color. + +Occasionally, on a clear, bright ("high") night, when the moon is full, +prior to rising, when just below the horizon, it will so illuminate this +lower strata of atmosphere as to appear like a great fire; the moon +rises red, but its deep color gradually fades as it rises, and when well +up in the heavens we perceive that this deep coloring was an illusion +and merely the influence of its surroundings. I never, though, knew of +any one to attempt to account for this by "meteoric dust;" and yet it is +an embodiment of the same principle. Place the sun where the moon is, +and from its far superior abundance of light we have a much grander +display. + +Under no other conditions or relations of the sun and earth is it +possible to have this phenomenon of the delicate red sky but when a +positive area of high barometer is passing and extends over us. In +order to produce this effect we must have the clear atmosphere of high +barometer, when there is a minimum of moisture present. The action of +the sun's rays upon this extensive area of slightly moist rarefied +air is unconfined by clouds, and reaches far and wide, and produces +a delicacy of color which from no other source or condition can be +realized. + +ISAAC P. NOYES. + +Washington, D. C., 1884. + + * * * * * + + + + +A THEORY OF COMETARY PHENOMENA. + + +_To the, Editor of the Scientific American_: + +The following subject, substantially, was written more than a year ago +with a view to its publication. It was not, however, until January of +the present year that I sent a brief communication to the _Brooklyn +Eagle_, which was published Feb. 3, giving my views in relation to +cometary phenomena. With this I might remain satisfied, were it not +that the interesting paper by G. D. Hiscox, published in the SCIENTIFIC +AMERICAN SUPPLEMENT, Feb. 16, impressed me with the idea that the theory +I advanced might assist in explaining others, if brought to the notice +of those interested through the columns of your valuable journal. + +The theory that I advance to account for the several phenomena relating +to comets' tails is, that comets are non-luminous, transparent bodies; +that they transmit the light of the sun; that the transmitted light +reflected by the particles of matter in space constitutes the tails of +comets. "Like causes produce like effects." By contraries, then, like +effects must be produced by similar causes; for, if an effect produced +by a cause which is known is similar to an effect produced by a cause +which is not known, the cause which is known must be similar to the +cause which is not known. This is true or not. + +I submit the following experiments to substantiate the theory advanced. + +Partially fill a vial or a tumbler with water, hold it by the rim, +and move it around a lighted candle placed upon a table. A shadow +surrounding the transmitted light will be cast upon the table. As the +tumbler approaches the light, the shadow follows the tumbler, and when +receding the tumbler follows the shadow; and as the tumbler is moved +around the light, the shadow will swing round from one side to the +other. If the tumbler be held so that a puff of smoke can be blown +into the transmitted rays, the particles of smoke will reflect the +transmitted light, and will illustrate my idea of what constitutes a +comet's tail. A dark band may be observed in this stream of light, as +also in the light cast upon the table. + +In these experiments, we see the effects produced by a cause which is +known; the effects are similar to those observed in the tails of comets, +the cause of which we do not know; but is it not reasonable to assume +that the cause is similar? + +Assuming now that comets are transparent, can any other phenomena +peculiar to comets be accounted for upon this hypothesis? Next to +the tail itself, the curve is the most noticeable feature, and if we +consider the extraordinary length of these appendages, the astounding +velocity at which comets move in their orbits, and the time that would +elapse before a ray of light, emitted from the nucleus, would reach the +end of the tail, perhaps the curve--which, if I am not deceived in my +observations, always dips toward its orbit--can be accounted for. If a +comet moved in a direct line toward the center of the sun, there would +be no curve to the tail. But taking Donati's comet of 1858 as an +example, the tail of which was said to be about 200,000,000 miles long, +a ray of light traveling at the rate of 192,000 miles per second would +be about twenty minutes in going from the nucleus to the end of the +tail. + +But during that time the comet would move in its orbit, say, 50,000 +miles, and as light moves in a straight line, and other rays are +constantly emerging from the nucleus as it moves along in its course, +the result is that the tail has a curved appearance. + +I have no data at hand regarding this comet, but what I have said will +serve to illustrate my ideas. Again, referring to this comet, I remember +to have read the statement of an astronomer that, after passing round +the sun, a new tail was formed opposite the original one. Now, it seems +to me that that is just what would happen, for in moving round the sun +the comet would travel say 3,000,000 miles; the greater portion of the +tail then, would extend millions of miles upon one side of the sun, +while from the nucleus upon the opposite side of the sun a new tail +would appear to be formed. + +Upon this hypothesis, the extraordinary length of their tails and the +fact that stars are visible through the densest portion of them is +explained; as also the fact that they so rapidly disappear from view +when moving from the sun, the light received by them from the sun +being in proportion to their distance from it, and but little of that +reflected. + +JOHN M. HUGHES. + +Brooklyn, N. Y. + + * * * * * + +[FOR THE SCIENTIFIC AMERICAN.] + + + + +ON COMETS. + + +When we see a comet approaching the sun with its tail following in the +orbit of the nucleus, we have no great difficulty in believing the +common theory that a comet consists of nucleus attracted toward the sun, +while the tail is repelled; and that we see the whole of it. But as it +approaches the sun, difficulties arise that make us doubt whether the +theory be true. + +Let us suppose a comet with a tail 50,000,000 miles in length, and that +it will require two days to pass round the sun. Now the tail, being +always in a line drawn through the center of the sun and center of the +nucleus, will, when it reaches the long axis of the elliptical orbit, +stand perpendicularly to the orbit of the nucleus. That is, the +extremity of the tail farthest from the sun, in addition to its onward +motion, has acquired a lateral motion that has lifted it 50,000,000 +miles in the first day of its perihelion. The velocity of the extremity +has been vastly accelerated over that of the nucleus, and it has +moreover a sheer lift above the orbit of the nucleus. Now this lift is +in opposition to gravity; neither is it in consequence of any previous +momentum, for its velocity is accelerated and its previous momentum +would be a hindrance; nor is the lift in consequence of any repelling +force from the sun, for such force would be diminished in proportion to +the square of the distance, and the far end would be acted on less than +the nucleus end of the tail, whereas the velocity of the former is +increased a hundred fold over that of the latter. A polar force in the +comet would merely draw the comet into the sun. We therefore find no +force adequate for such a lift, but on the contrary all the forces are +opposed to it. + +But if the first day of the perihelion overwhelms us with difficulty, +the second day will prove disastrous to the common theory. For the +extremity of the tail farthest from the sun will be required to pass +with lateral motion from its perpendicular 100,000,000 miles, so that it +may be in advance of the nucleus and again rest on its orbit. This orbit +is an impassable line, and therefore instantly arrests the prodigious +lateral velocity of the tail. That impassable orbital line is to it +as solid and inflexible as a wall of adamant. The motion so instantly +arrested would be disastrous to any tail, whether composed of gas, +meteorites, or electricity, whatever that may be. + +Having shown that the common theory of comets is filled with insuperable +difficulties, I will again call attention to a theory proposed about +eighteen months ago in the SCIENTIFIC AMERICAN. + +According to this theory, a comet consists of a nucleus and an +atmosphere, for the most part invisible, surrounding it on all sides to +an extent at least equal to the length of the tail. The rays of the sun +in passing through or near the nucleus are so modified as to become +visible in their further progress through the cometic atmosphere, while +all the rest remain invisible. What we call the tail is merely a radius +of the cometic atmosphere made visible, and as the comet moves through +space, only different portions of the atmosphere come in sight, in +obedience to the ordinary laws of light. There is no difficulty in +accounting for the rise and fall of the tail at perihelion, nor for the +tail preceding the nucleus afterward. + +The spherical theory accounts easily for the different forms of tail +seen in different comets. The sword shaped tails, at variance with the +common theory, can be accounted for by supposing a slight difference in +density or material in the cometic atmosphere, which will deflect the +light as seen. The comet of 1823, which cannot be explained on the +common theory, is very easily explained on the spherical. That comet +showed two tails, apparently of equal length, which moved opposite to +each other, and perpendicularly to the orbit of the nucleus, and showing +no signs of repulsive force from the sun. On the spherical theory it is +only necessary to suppose such an arrangement of the nucleus as would +reflect the rays of the sun laterally; a slight modification of the +nucleus would give not only two but any number of tails pointing in +different directions. + +It may be objected to the spherical theory that a tail 50,000,000 miles +long would call for a sphere 100,000,000 miles in diameter, and that +would be too vast for our solar system. But it is claimed for this +sphere that it consists of the same material as the so-called tail, and +that it has the same capability of moving among planets without manifest +disturbance to either. + +The sphere at the perihelion would envelop the sun, and as a noticeable +reduction is sometimes found in its so-called tail, the cometic +atmosphere may impart to the sun at that time whatever is necessary to +its use. + +That there is something in common between the sun's corona and cometary +matter was shown by the last solar eclipse observed in South Pacific +Ocean, where the spectrum of sun's corona was found to be the same as +that of a comet's tail. Are we to attribute in any degree the different +appearances of the sun's corona to the presence or absence of a comet +at its perihelion? At the eclipse of the sun seen in Upper Egypt two or +three years ago, a comet was seen close to the sun, but I have seen no +account of the appearance of the corona at that time. + +FURMAN LEAMING, M.D. + +Romney, Tippecanoe Co. Indiana. + + * * * * * + + + + +FORMS OF IVY. + + +It is scarcely possible for us to bee too emphatic in our praises of the +most distinct forms of ivy, since but few other hardy climbing plants +ever give to us a tithe of their freshness and variety. A good long +stretch of wall covered with a selection of the best green-leaved kind +is always interesting, and never more so than during the winter months, +especially if at intervals the golden Japanese jasmine is planted among +them or a few plants of pyracantha or of Simmon's cotoneaster for the +sake of their coral fruitage. The large-leaved golden ivy is also very +effective here and there along a sunny wall, especially if contrasted +with the small-leaved kind--atropurpurea--which has dark purple or +bronzy foliage at this season. Of the large-leaved kinds, one of the +most distinct is canariensis, or large-leaved Irish ivy, and Raegner's +variety, with leathery, heart-shaped foliage, is also handsome. The +birdsfoot ivy (pedata) is curious, as it clings to the stones like +delicate leaf embroidery, and for shining green leafage but few equal +to the one called lucida. The two other kinds sketched are hastata and +digitata, both free growing and distinct sorts. + +[Illustration: VARIOUS FORMS OF IVY. Heart-leaved Ivy (Hedera +Raegenerana). Glossy Ivy (H. lucida). Arrow-leaved Ivy (H. hastata).] + +_Ivy Leaves_.--Common ivy is tolerably plentiful nearly everywhere, but +it is not common to find a good distinct series of its many varieties +even in the best gardens. Of all the different forms of ivy, I think +the large-leaved golden one of the best; certainly the best of the +variegated kinds. Raegner's variety is also very bold, its great glossy, +heart-shaped leaves most effective. Algeriensis is another fine-leaved +kind, the form dentata producing foliage even still larger when well +grown. For making low evergreen edgings on the turf, for carpeting +banks, the covering of bare walls and the old tree stumps, we have no +other evergreen shrub so fresh and variable, or so easily cultivated as +are these forms of the ivy green. Perhaps one reason why the finer kinds +of ivy are comparatively uncommon is the fact that a strong prejudice +exists against ivy in many minds. It is an erroneous notion that ivy +injures buildings against the walls of which it is planted; it never +injures a good wall, nor a sound house, but on the contrary, hides and +softens the stony bareness of the one and adds beauty and freshness to +the other.--_The Garden_. + +[Illustration: VARIOUS FORMS OF IVY. Finger-leaved Ivy (H. Itata). Irish +Ivy (H. canariensis). Rira's foot Ivy (H. pedata).] + + * * * * * + + + + +PROPAGATING ROSES. + + +In an article on this subject an English horticultural journal describes +the method pursued by a London florist. After stating that out of a case +containing 310 cuttings only five failed to root, the article proceeds: +The case or box is made of common rough deal boards. It is five feet +six inches long and one foot in depth. Within half an inch of the top a +groove is cut inside the box, into which the glass is slid, after the +manner of a sliding box lid. In the end of the third week in July the +box was placed in the kitchen garden under the shadow of a high north +wall; it was then about half filled with good turfy loam, to which had +been added a little leaf mould and a good sprinkling of sharp sand. The +soil was then pressed down very firmly (the box being nearly half full +when pressed), and then thoroughly well soaked with rain water, and +allowed to stay uncovered until the next day. The next day good stout +cuttings were taken of all the roses, both tea and hybrid perpetual, +which it was desired to add to the stock. They were then inserted +closely and firmly in the soil, just over the bottom leaf, the glasses +were slipped on and puttied down; the grooves in which the glass slid, +and even the joints in the glass, being filled with putty, so as to +exclude the air. The whole thing completed, nothing more remained to be +done but to leave the box in its cool, shady nook for five or six weeks, +when the growing points of the free starting kinds gave notice that the +glasses might be removed, a bit at a time, with safety. Nothing could be +more simple, or demand less skill, and the operation may be carried out +successfully by an amateur at any time during the season, when good firm +cuttings can be got, and when six weeks' tolerably fine weather may be +counted on. The success of the whole thing depends on having the glasses +fixed so that they may not be removed until the cuttings are rooted, and +in placing the boxes in a shady place. So treated, carnations and many +of our shrubs and herbaceous perennials may be propagated by unskilled +persons with certainty, and without much trouble. + + * * * * * + + + + +A FEW OF THE BEST INULAS. + + +Of the fifty-six species of Inula described in scientific works, +probably not more than thirty are at present in cultivation in +this country, and those are chiefly confined to botanic gardens, +notwithstanding the fact that many of them are useful garden plants. +They are principally distributed throughout Southern Europe, although we +find them extending to Siberia and the Himalayas; indeed, it is to the +Himalayas we are indebted for the kinds that are most ornamental. Some +of the low-growing species are extremely useful for the rockery, such +as I. montana (the Mountain Inula), a fine dwarf plant with woolly +lanceolate leaves and dense heads of orange-colored flowers, resembling +in habit and general appearance some of the creeping Hieraciums. It is a +handsome and desirable plant for the decoration of old walls and similar +places, where it can be a little sheltered from rain and drip. Another +very useful species for this purpose is I. rhizocephaloides, found +plentifully in the Himalayas. It is one of the prettiest Alpine +composites we have. It seldom attains more than from one inch to two +inches in height, forming a dense rosette of short, hairy, oval leaves, +in the center of which the bright purple involucres, in the form of a +ball, are extremely interesting. It is easily cultivated, requiring, +however, a rather snug nook, where it will not be allowed to become too +dry. It is best propagated from seed. Then there is the woolly Inula (I. +candida), a pretty plant with small oval leaves, covered with a thick, +silky down, and much in the way of the white-leaved I. limonifolia, both +of which are very effective when grown in masses, which should always +be low down near the front of a rockery, or as an edging for a mixed +border. The glandular-leaved Inula (I. glandulosa), of which a good +representation is here given, is a beautiful hardy perennial. It is a +native of Georgia and the Caucasian Alps, near the Caspian Sea. It is +a rather robust-growing species, with large, bright, orange-yellow +flowers, varying from three to five inches in diameter, the narrow and +very straggly ray florets contrasting nicely with the rather prominent +disk. The leaves, although quite entire, seem notched, owing to large +black glands which form on their margins. They are lanceolate, and clasp +the stem. The plant is very variable, both as regards robustness and +size of flowers, and this may in a measure account for the confusion +existing between it and I. Oculus-Christi. + +The soil most suitable for the full development of I. glandulosa is a +strong, clayey, retentive loam; it does not thrive well in the light +shallow soils in the neighborhood of London, except in shady positions. +I. Hookeri is a free-flowering perennial, with pointed lanceolate +leaves, of a delicate texture, bright green, and very finely toothed. +The flowers, which are sweet-scented, are not so large as those of I. +glandulosa, and are produced singly, the ray florets being, however, +much more numerous, rarely numbering less than thirty. It is found in +abundance in rocky places in Sikkim, where it replaces the nearly allied +I. grandiflora, a dwarfer species, with much shorter, shining leaves; +both are very desirable plants either for rockery or flower border work. +The Elecampane (I. Helenium) is an imposing, robust-growing species, +having large, broad leaves a foot or more in length. It grows from four +feet to five feet in height, and its thick, shaggy branches are crowned +with large yellow flowers. For isolating in woods this plant, is very +useful, and with the exception of Telekia cordifolia, it would be hard +to find a rival to it. It is, I believe, pretty extensively used for +planting in shrubberies, but unless they are thin and open it is seldom +seen to advantage. It is found wild or naturalized in some parts of +England. It flowers in June and July, and even into August when the +season has been favorable. + +[Illustration: INULA GLANDULOSA (_flowers deep yellow_.)] + +For naturalizing in woods the following will be found useful, _viz_., I. +salicina, I. Oculus-Christi, I. squarrosa, I. britannica, and many more, +the true beauty of which can only be realized in this way. With the +exception of I. rhizocepbaloides, they are all propagated by division +with the greatest ease, or by seed, which is best sown as soon as it is +ripe.--_D.K., The Garden_. + + * * * * * + + + + +FRUIT GROWING. + +By P.H. FOSTER. + + +In the first place, if you contemplate appropriating a portion of your +land for the raising of fruits, you should have the orchard so situated +that no large animals can run at large on the grounds. Prepare your soil +in the most thorough manner; underdrain, if necessary, to carry off +surplus water; dig deep, large holes; fill in the bottom with debris; +in the very bottom put a few leaves, clam and oyster shells, etc., then +sods; above and below the roots put a good garden or field soil; do not +give the trees fresh manure at the time of setting, but the following +fall manure highly with any kind on top of the ground; dig it in the +following spring; keep the soil frequently worked during the summer, +and, if convenient, mulch with hay, straw, or leaves. + +Now you are on the road to progress, provided you have made no mistake +in the selection of your trees. The purposes for which you intend your +fruit is highly important. You should well consider at the outset if +for family or market use. This is a business which requires a long look +ahead, for it is said, "He who plants pears looks ahead for his heirs." + +Caution should be used in procuring your stock; little should be planted +that is not fairly tested on the Island, purchased of parties who can be +fully relied upon to give you what you want. Do not buy your stock of +parties who carry labels in their pockets to make to order what you want +out of the same bundle of trees. + +Now, having your trees set out in a proper manner, of such varieties +as you desire, the next important step is to bring the trees into +usefulness. My plan is to use bone--fine bone--very freely about every +three years. Another important matter is that of trimming. "Fire +purifies," and the knife regulates the grand balance or equilibrium +between roots and tops. In most cases the top outgrows the roots, the +consequence of which is an ultimate weakness of the tree. It is thrown +into excessive fruiting, disease, and premature decay. To avoid this +result, use the knife when required. Thin out the inside branches when +small, and if the tree does not make a satisfactory growth, cut back +half way to the ground. + +We will suppose that you have got your trees growing nicely, and they +have begun to bear fruit. There are other important steps to be taken, +which will be of little cost to you. Provide a wind-break for the +orchard. Evergreens answer the purpose, being a protection against the +wind. Having this matter attended to, there are other enemies with which +we must contend. I refer to the apple and peach tree borers. The former +will live in the tree for three years, if unmolested; the latter, one +year only. They are very easily destroyed by looking over the trees and +taking them out with a knife; or maybe prevented from touching the trees +by wrapping a piece of felt paper, 8 inches wide, around the tree near +the ground, the bottom being covered with dirt and the top tied tightly +above. The pear is not generally disturbed by these insects--only the +apple, peach, and quince. We have another insect very destructive to the +plum, peach, cherry, and apple--the _curcutio_, or plum weavel. This +season for the first time in twenty years we have gathered a small +crop of that very desirable plum, the Purple Favorite. We simply threw +air-slaked lime over the trees nearly every morning for from four to six +weeks, from the time the tree was out of bloom. Peach trees should be +treated in the same manner. Another method of fighting this insect is to +spread a sheet under the tree, and with a blow jar off the little Turk +and secure him on the sheet. But I consider the lime procedure the less +trouble and more effective. The tent caterpillar, which is easily seen, +should be destroyed at once. We have yet another insect to contend with +which infests the apple and pear, commonly called the Coddling Moth, +and the larva, the apple-worm (_Garpocapsa pomonella_). The loss by the +ravaaes of this insect alone to the fruit growers of the United States +fan hardly be estimated, as in many cases the whole crop is rendered +worthless. Such a vast destruction of two of the most valuable fruits +the world produces should stimulate scientists in this age of progress +to discover an effectual remedy against such a gigantic evil. + +I have never yet discovered nor tried an effectual remedy against this +insect. The nearest I have approached his extermination is in the +following manner: After it has entered the fruit and accomplished its +damage, the time arrives when it has to leave the fruit and hide itself +in a quiet, secure position to undergo the transition from the larva to +the pupa state, which requires, in the early part of the season, eight +or ten days; after this time the miller is hatched and is again ready to +besiege the fruit with its sting. The insect, being two-brooded in this +climate at least, if not disturbed, has an aggregating force to do +mischief the second time. The progeny for the succeeding year have alone +to depend on the security of this second generation of larvae. As they +may often be found in bark of apple trees during winter, my plan of +destruction is, about the first of July to take woolen rags long enough +to wrap around the trees, and say four inches wide. Each week I look +over the trees, and destroy the worms secreted under the rags and +wherever I find them until the fruit is off the trees. I have all the +green fruit, of every kind, carefully picked up as soon as it falls, +thereby destroying many of the curculio as well as the apple-worms. + +One word upon the grape--the insect part of the question. The +_Phylloxera vastatrix_, or grape-vine louse, is already at work on Long +Island. It is found very difficult to raise many of our fine, new grapes +with us in consequence of the depredations of this very minute insect, +it being almost too small to be seen by the naked eye. There has lately +been discovered a remedy which is entirely chemical and as yet but +little disseminated. Very soon, no doubt, a discovery will be made that +will stay the progress of this destructive enemy. + +We should plant aplenty of cherry and small fruit trees to yield feed +for birds. In return they will assist us in our efforts to preserve a +bountiful supply of this health producing element. + + * * * * * + + + + +COARSE FOOD FOR PIGS. + + +A recent subscriber wants advice how to feed pigs of 25 to 35 pounds +weight, that are to be kept over winter and fitted for sale at about six +months old--whether coarse food will not help them as much in winter as +in summer. How roots and pumpkins will answer in lieu of grass, and what +can be fed when this green food is gone? He has had poor success in +growing young pigs on corn alone. He has a reasonably warm pen for +winter. + +The question of food is constantly recurring, and this is one of the +best evidences of the advancement of the country in the feeder's +art. When people are making no inquiry as to improved methods in any +direction, no progress can be made. There has been more progress made +in the philosophy of feeding during the last thirty years than in the +century and a half previous. + +In pig feeding in the dairy districts, young pigs generally grow up in +a very healthy condition, owing to the refuse milk of the dairy, which +furnishes the principal food of young pigs. Skim-milk contains all the +elements for growing the muscles and bones of young pigs. This gave them +a good, rangy frame, and, when desired, could be fed into 400 or 500 +pounds weight. But the fault attending this feeding was, that it was too +scanty to produce such rapid growth as is desired. It took too long to +develop them for the best profit. It had not then been discovered by the +farmer that it costs less to put the first hundred pounds on the pig +than the second, and less for the second than the third, etc.; that it +was much cheaper to produce 200 pounds of pork in six months than in +nine and twelve months. When it became evident that profit required more +rapid feeding, then they began to ply them continually with the most +concentrated food--corn meal or clear corn. If this was fed in summer, +on pasture, no harm was observed, for the grass gave bulk in the +stomach, and the pigs were were healthy and made good progress. But if +the young pigs were fed in pen in winter upon corn meal or clear corn, +the result was quite different; this concentrated food produced feverish +symptoms, and the pigs would lose their appetite for a few days, +drinking only water, which, after a while, would relieve the stomach, +and the pigs would eat vigorously again. Now, had they been fed a few +quarts of turnips, carrots, beets, or pumpkins, to give bulk to the +stomach, and separate the concentrated food, no harm would have come. +This gives the gastric juice a free circulation through the contents of +the stomach, the food is properly digested and applied to the needs of +the body instead of causing fever by remaining in the stomach.--_Live +Stock Journal_. + + * * * * * + + + + +METE KINGI. + + +Our engraving is a portrait of a familiar character in New Zealand, +chief Mete Kingi, who recently died at the age of one hundred years. +He was a fine specimen of the Maori race, the native New Zealanders, a +branch of the Malayo-Polynesian family. The New Zealanders surpassed +all other people in the art of tattooing, to which their chiefs gave +especial attention. Mete Kingi, as our picture shows, was no exception. +Tattooing on the face they termed _moko_. The men tattoo their faces, +hips, and thighs; the women their upper lips; for this purpose charcoal +made from kauri gum is chiefly used. It has the blue color when pricked +into the skin, growing lighter in shade in the course of years. The +subject of our illustration embraced Christianity, and was much +respected. Our engraving is from the _Illustrated Australian News_. + +[Illustration: THE LATE MAORI CHIEF METE KINGI.] + + * * * * * + + + + +LAKE TAHOE. + + +Some very interesting information by Prof. John Le Conte, is given in +the _Overland Monthly_, being the result of some physical observations +made by the author at Lake Tahoe, in 1873. Lake Tahoe, also called Lake +Bigler, is situated at an altitude of 6,247 feet in the Sierra Nevada +Mountains, partly in California, partly in Nevada. The lake has a length +of 22 and a width of 12 miles. As regards its origin, the author regards +it as a "plication hollow," or a trough produced by the formation of two +mountain ridges, afterward modified by glacial agency. The depth of the +lake is remarkable; the observations taken at ten stations along the +length of the lake gave the following depths in feet: 900, 1,385, 1,495, +1,500, 1,506, 1,540, 1,504, 1,600, 1,640, 1645. This depth exceeds that +of the Swiss lakes proper--Lake Geneva, for example, has a maximum depth +of 1,096 feet--but is considerably less than that of Lakes Maggiore and +Como, on the Italian side of the Alps. A series of observations of the +temperature of the water were taken between the 11th and 18th of August. +The average corrected results are as follows: + + Depth in feet. Temp. (C.) + 0(surface).................................19.4 + 50..........................................17.2 + 100..........................................12.8 + 150..........................................10.0 + 200.......................................... 8.9 + 250.......................................... 8.3 + 300.......................................... 7.8 + 330 (bottom)................................. 7.5 + 400.......................................... 7.2 + 480 (bottom)................................. 6.9 + 500.......................................... 6.7 + 600.......................................... 6.1 + 772 (bottom)................................. 5.0 + 1506 (bottom)..............,.................. 4.0 + +The temperature, therefore, diminishes with increasing depth to about +700 or 800 feet, and below this remains sensibly the same down to 1,506 +feet; or in other words, a constant temperature of 4 deg. C. prevails at all +depths below about. 820 feet. This is in accordance with the theory, the +temperature named being that of the maximum density of water, and it +confirms the recent observations of Prof. Forel in Switzerland; he +found, for example, that a constant temperature of 4 deg. C. was reached in +Lake Zurich at a depth of nearly 400 feet, the lake being then covered +with 4 inches of ice. The explanation of the observed fact that Lake +Tahoe does not entirely freeze over even in severe winters is found in +the extreme depth; and the fact that the bodies of drowned persons do +not rise to the surface after the lapse of the usual time is explained +by the low temperature prevailing near the bottom, which does not allow +the necessary decomposition to go forward so as to produce the ordinary +result. + +The water of Lake Tahoe is remarkable both for its transparency and +beauty of color. A series of observations made at the close of August or +beginning of September showed that a horizontally adjusted dinner plate +of about 91/2 inches diameter was visible at noon at a depth of 108 feet. +The maximum depth of the limit of visibility as found by Prof. Forel, in +Lake Geneva, was 56 feet. He showed, moreover, that this limit is much +greater in. winter than in summer, as explained in part by the greater +absence of suspended matter and in part by the fact that increase of +temperature increases the absorbing power of water for light. The +maximum depth of visibility in the Atlantic Ocean, as found by Count +de Pourtales, was 162 feet, and Prof. Le Conte states his belief that +winter observations in Lake Tahoe would place the limit at even a +greater depth than this. The author gives a detailed and interesting +discussion in regard to the blue color of lake waters, reviewing in full +the results of previous writers on the subject, and concludes that while +pure water unquestionably absorbs a larger part of the red end of the +spectrum, and hence appears blue by transmitted light, the color seen by +diffuse reflection is mainly due to the selective reflection from the +fine particles suspended in it. + +The last subject discussed by the author is that of the rhythmical +variations of level, or "seiches," of deep lakes; he applies the usual +formula to Lake Tahoe, and calculates from it the length of a complete +longitudinal and of a transverse "seiche;" these are found to be +eighteen or nineteen minutes in the first case and thirteen minutes in +the second. + + * * * * * + +A catalogue, containing brief notices of many important scientific +papers heretofore published in the SUPPLEMENT, may be had gratis at this +office. + + * * * * * + + + + +THE SCIENTIFIC AMERICAN SUPPLEMENT. + +PUBLISHED WEEKLY. + +TERMS OF SUBSCRIPTION, $5 A YEAR. + + +Sent by mail, postage prepaid, to subscribers in any part of the United +States or Canada. 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C. + + + + + +End of the Project Gutenberg EBook of Scientific American Supplement, +No. 433, April 19, 1884, by Various + +*** END OF THE PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN SUP., NO. 433 *** + +This file should be named 7043310.txt or 7043310.zip +Corrected EDITIONS of our eBooks get a new NUMBER, 7043311.txt +VERSIONS based on separate sources get new LETTER, 7043310a.txt + +Produced by J. Niehof, D. Kretz, J. Sutherland, and Distributed Proofreaders + +Project Gutenberg eBooks are often created from several printed +editions, all of which are confirmed as Public Domain in the US +unless a copyright notice is included. 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Vol. XVII, No. 433. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + + * * * * * + +TABLE OF CONTENTS. + +I. CHEMISTRY, METALLURGY, ETC.--New Analogy between + Solids, Liquids, and Gases. + + Hydrogen Amalgam. + + Treatment of Ores by Electrolysis.--By M. KILIANI. + +II. ENGINEERING, AND MECHANICS.--Electric Railway at Vienna.--With + engraving. + + Instruction in Mechanical Engineering.--Technical and trade + education.--A course of study sketched out.--By Prof. R.H. + THURSTON. + + Improved Double Boiler.--3 figures. + + The Gardner Machine Gun.--With three engravings showing the + single barrel, two barrel, and five barrel guns. + + Climbing Tricycles. + + Submarine Explorations.--Voyage of the Talisman.--The Thibaudier + sounding apparatus.--With map, diagrams, and engravings. + + Jamieson's Cable Grapnel.--With engraving. + + A Threaded Set Collar. + +III. TECHNOLOGY.--Wretched Boiler Making. + + Pneumatic Malting.--With full description of the most improved + methods and apparatus.--Numerous figures. + + Reducing and Enlarging Plaster Casts. + + Stripping the Film from Gelatine Negatives. + +IV. ELECTRICITY.--Non-sparking Key. + + New Instruments for Measuring Electric Currents and Electromotive + Force.--By MESSRS. K.E. CROMPTON and GISBERT + KAPP.--Paper read before the Society of Telegraph Engineers.--With + several engravings. + + When Does the Electric Shock Become Fatal? + +V. ART AND ARCHÆOLOGY.--Robert Cauer's Statute of Lorelei.--With + engraving. + + The Pyramids of Meroe.--With engraving. + +VI. ASTRONOMY AND METEOROLOGY.--The Red Sky.--Cause of + the same explained by the Department of Meteorology. + + A Theory of Cometary Phenomena. + + On Comets.--By FURMAN LEAMING, M.D. + +VII. NATURAL HISTORY.--The Prolificness of the Oyster. + + Coarse Food for Pigs. + +VIII. BOTANY, HORTICULTURE, ETC.--Forms of Ivy.--With + several engravings. + + Propagating Roses. + + A Few of the Best Inulas.--With engraving. + + Fruit Growing.--By P.H. FOSTER. + +IX. MEDICINE, HYGIENE, ETC.--A People without Consumption, + and Some Account of Their Country, the Cumberland Tableland. + --By E.M. WIGHT. + + The Treatment of Habitual Constipation. + +X. MISCELLANEOUS.--The French Scientific Station at Cape Horn. + +XI. BIOGRAPHY.--The Late Maori Chief, Mete Kingi.--With portrait. + + * * * * * + + + + +THE FRENCH SCIENTIFIC STATION AT CAPE HORN. + + +In 1875 Lieutenant Weyprecht of the Austrian navy called the attention +of scientific men to the desirability of having an organized and +continual system of hourly meteorological and magnetic observations +around the poles. In 1879 the first conference of what was termed the +International Polar Congress was held at Hamburg. Delegates from eight +nations were present--Germany, Austria, Denmark, France, Holland, +Norway, Russia, and Sweden. + +The congress then settled upon a programme whose features were: 1. To +establish general principles and fixed laws in regard to the pressure +of the atmosphere, the distribution and variation of temperature, +atmospheric currents, climatic characteristics. 2. To assist the +prediction of the course and occurrence of storms. 3. To assist the +study of the disturbances of the magnetic elements and their relations +to the auroral light and sun spots. 4. To study the distribution of +the magnetic force and its secular and other changes. 5. To study the +distribution of heat and submarine currents in the polar regions. 6. To +obtain certain dimensions in accord with recent methods. Finally, to +collect observations and specimens in the domain of zoology, botany, +geology, etc. + +The representatives of the various nations had several conferences +later, and by the 1st of May, 1881, there were sufficient subscribers to +justify the establishment of eight Arctic stations. + +France entered actively in this work later, and its first expedition was +to Orange Bay and Cape Horn, under the surveillance and direction of +the Academy of Sciences, Paris, and responsible to the Secretary of the +Navy. On the 6th of September, 1882, this scientific corps established +itself in Orange Bay, near Cape Horn, and energetically began its +serious labors, and by October 22 the greater part of their preliminary +preparations was completed, comprising the erection of a magnetic +observatory, an astronomic observatory, a room for the determination of +the carbonic anhydride of the air, another for the sea register, and +a bridge 92 feet long, photographic laboratory, barometer room, and +buildings for the men, food, and appurtenances, together with a +laboratory of natural history. + +In short, in spite of persistent rains and the difficulties of the +situation, from September 8 to October 22 they erected an establishment +of which the different parts, fastened, as it were, to the flank of a +steep hill, covered 450 square meters (4,823 square feet), and rested +upon 200 wooden piles. + +From September 26, 1882, to September 1, 1883, night and day +uninterruptedly, a watch was kept, in which the officers took part, so +that the observations might be regularly made and recorded. Every four +hours a series of direct magnetic and meteorological observations was +made, from hour to hour meteorological notes were taken, the rise and +fall of the sea recorded, and these were frequently multiplied by +observations every quarter of an hour; the longitude and latitude were +exactly determined, a number of additions to the catalogue of the fixed +stars for the southern heavens made, and numerous specimens in natural +history collected. + +The apparatus employed by the expedition for the registration of the +magnetic elements was devised by M. Mascart, by which the variations +of the three elements are inscribed upon a sheet of paper covered with +gelatine bromide, inclination, vertical and horizontal components, with +a certainty which is shown by the 330 diurnal curves brought back from +the Cape. + +The register proper is composed of a clock and a photographic frame +which descends its entire length in twenty-four hours, thus causing the +sensitized paper to pass behind a horizontal window upon which falls the +light reflected by the mirrors of the magnetic instruments. One of those +mirrors is fixed, and gives a line of reference; the other is attached +to the magnetic bar, whose slightest movements it reproduces upon the +sensitized paper. The moments when direct observations were taken were +carefully recorded. The magnetic _pavilion_ was made of wood and copper, +placed at about fifty-three feet from the dwellings or camp, near the +sea, against a wooded hill which shaded it completely; the interior +was covered with felt upon all its sides, in order to avoid as much as +possible the varying temperatures. + +The diurnal amplitude of the declination increased uniformly from the +time of their arrival in September up to December, when it obtained +its maximum of 7'40", then diminished to June, when it is no more than +2'20"; from this it increased up to the day of departure. The maximum +declination takes place toward 1 P.M., the minimum at 8:50 A.M. The +night maxima and minima are not clearly shown except in the southern +winter. + +The mean diurnal curve brings into prominence the constant diminution +of the declination and the much greater importance of the perturbations +during the summer months. These means, combined with the 300 absolute +determinations, give 4' as the annual change of the declination. + +M. Mascart's apparatus proved to be wonderfully useful in recording the +rapid and slight perturbations of the magnet. Comparisons between the +magnetic and atmospheric perturbations gave no result. There was, +however, little stormy weather and no auroral displays. This latter +phenomenon, according to the English missionaries, is rarely observed in +Tierra del Fuego. + +The electrometer used at the Cape was founded upon the principle +developed by Sir William Thomson. The atmospheric electricity is +gathered up by means of a thin thread of water, which flows from a +large brass reservoir furnished with a metallic tube 6.5 feet long. The +reservoir is placed upon glass supports isolated by sulphuric acid, and +is connected to the electrometer by a thread of metal which enters a +glass vessel containing sulphuric acid; into the same vessel enters a +platinum wire coming from the aluminum needle. Only 3,000 observations +were given by the photographic register, due to the fact that the +instruments were not fully protected against constant wet and cold. + +Besides these observations direct observations of the magnetometer were +made, and the absolute determination of the elements of terrestrial +magnetism attempted. + +On the 17th of November, 1882, a severe magnetic disturbance occurred, +lasting from 12 M. until 3 P.M., which in three hours changed the +declination 42'. The same perturbation was felt in Europe, and the +comparison of the observations in the two hemispheres will prove +instructive. + + * * * * * + + + + +THE ELECTRIC RAILWAY AT VIENNA. + + +The total length of this railway, which extended from the Eiskeller in +the Schwimmschul-Allee to the northern entrance of the Rotunda, was +1528.3 meters; the gauge was 1 meter, and 60 per cent. of the length +consisted of tangents, the remaining 40 per cent. being mostly curves +of 250 meters radius. The gradients, three in number, were very small, +averaging about 1:750. + +Two generating dynamos were used, which were coupled in parallel +circuit, but in such a manner that the difference of potential in both +machines remained the same at all times. This was accomplished by the +well known method of coupling introduced by Siemens and Halske, in which +the current of one machine excites the field of the other. + +Although the railroad was not built with a view of obtaining a high +efficiency, an electro-motive force of only 150 volts being used, a +mechanical efficiency of 50 per cent. was nevertheless obtained, both +with one generator and one car with thirty passengers, as well as with +two generators and two cars with sixty passengers; while with two +generators and three cars (two of them having motors) the same result +was shown. + +[Illustration: THE ELECTRIC RAILWAY AT VIENNA.] + +The curves obtained by the apparatus that recorded the current showed +very plainly the action within the machines when the cars were started +or set in motion; at first, the current rose rapidly to a very high +figure, and then declined gradually to a fixed point, which corresponded +to the regular rate of speed. The tractive power, therefore, increases +rapidly to a value far exceeding the frictional resistances, but this +surplus energy serves to increase the velocity, and disappears as soon +as a uniform velocity is reached. + +The average speed, both with one and three cars, was 30 kilometers per +hour.--_Zeitsch. f. Elektrotechnik_. + + * * * * * + + + + +INSTRUCTION IN MECHANICAL ENGINEERING. + +By Professor R. H. THURSTON. + + +The writer has often been asked by correspondents interested in +the matter of technical and trade education to outline a course of +instruction in mechanical engineering, such as would represent his +idea of a tolerably complete system of preparation for entrance into +practice. The synopsis given at the end of this article was prepared +in the spring of 1871, when the writer was on duty at the U.S. Naval +Academy, as Assistant Professor of Natural and Experimental Philosophy, +and, being printed, was submitted to nearly all of the then leading +mechanical engineers of the United States, for criticism, and with a +request that they would suggest such alterations and improvements as +might seem to them best. The result was general approval of the course, +substantially as here written. This outline was soon after proposed as a +basis for the course of instruction adopted at the Stevens Institute of +Technology, at Hoboken, to which institution the writer was at about +that time called. He takes pleasure in accepting a suggestion that its +publication in the SCIENTIFIC AMERICAN would be of some advantage to +many who are interested in the subject. + +The course here sketched, as will be evident on examination, includes +not only the usual preparatory studies pursued in schools of mechanical +engineering, but also advanced courses, such as can only be taught in +special schools, and only there when an unusual amount of time can be +given to the professional branches, or when post graduate courses can be +given supplementary to the general course. The complete course, as here +planned, is not taught in any existing school, so far as the writer is +aware. In his own lecture room the principal subjects, and especially +those of the first part of the work, are presented with tolerable +thoroughness; but many of the less essential portions are necessarily +greatly abridged. As time can be found for the extension of the course, +and as students come forward better prepared for their work, the earlier +part of the subject is more and more completely developed, and the +advanced portions are taken up in greater and greater detail, each year +giving opportunity to advance beyond the limits set during the preceding +year. + +Some parts of this scheme are evidently introductory to advanced courses +of study which are to be taken up by specialists, each one being adapted +to the special instruction of a class of students who, while pursuing +it, do not usually take up the other and parallel courses. Thus, a +course of instruction in Railroad Engineering, a course in Marine +Engineering, or a course of study in the engineering of textile +manufactures, may be arranged to follow the general course, and the +student will enter upon one or another of these advanced courses as his +talents, interests, or personal inclinations may dictate. At the Stevens +Institute of Technology, two such courses--Electrical and Marine +Engineering--are now organized as supplementary of the general course, +and are pursued by all students taking the degree of Mechanical +Engineer. These courses, as there given, however, are not fairly +representative of the idea of the writer, as above expressed, since the +time available in general course is far too limited to permit them to be +developed beyond the elements, or to be made, in the true sense of the +term, advanced professional courses. Such advanced courses as the writer +has proposed must be far more extended, and should occupy the whole +attention of the student for the time. Such courses should be given in +separate departments under the direction of a General Director of the +professional courses, who should be competent to determine the extent of +each, and to prevent the encroachment of the one upon another; but they +should each be under the immediate charge of a specialist capable +of giving instruction in the branch assigned to him, in both the +theoretical and purely scientific, and the practical and constructive +sides of the work. Every such school should be organized in such a +manner that one mind, familiar with the theory and the practice of the +professional branches taught, should be charged with the duty of giving +general direction to the policy of the institution and of directing +the several lines of work confided to specialists in the different +departments. It is only by careful and complete organization in this, as +in every business, that the best work can be done at least expense in +time and capital. + +In this course of instruction in Mechanical Engineering it will be +observed that the writer has incorporated the scheme of a workshop +course. This is done, not at all with the idea that a school of +mechanical engineering is to be regarded as a "trade school," but that +every engineer should have some acquaintance with the tools and the +methods of work upon which the success of his own work is so largely +dependent. If the mechanical engineer can acquire such knowledge in the +more complete course of instruction of the trade school, either before +or after his attendance at the technical school, it will be greatly to +his advantage. The technical school has, however, a distinct field; and +its province is not to be confounded with that of the trade school. +The former is devoted to instruction in the theory and practice of a +profession which calls for service upon the men from the latter--which +makes demand upon a hundred trades--in the prosecution of its designs. +The latter teaches, simply, the practical methods of either of the +trades subsidiary to the several branches of engineering, with only so +much of science as is essential to the intelligent use of the tools and +the successful application of the methods of work of the trade taught. +The distinction between the two departments of education, both of which +are of comparatively modern date, is not always appreciated in the +United States, although always observed in those countries of Europe +in which technical and trade education have been longest pursued as +essential branches of popular instruction. Throughout France and +Germany, every large town has its trade schools, in which the trades +most generally pursued in the place are systematically taught; and every +large city has its technical school, in which the several professions +allied to engineering are studied with special development of those to +which the conditions prevailing at the place give most prominence and +local importance. + +A course of trade instruction, as the writer would organize it, would +consist, first, in the teaching of the apprentice the use of the tools +of his trade, the nature of its materials, and the construction and +operation of the machinery employed in its prosecution. He would next be +taught how to shape the simpler geometrical forms in the materials of +his trade, getting out a straight prism, a cylinder, a pyramid, or a +sphere, of such size and form as may be convenient; getting lines and +planes at right angles, or working to miter; practicing the working of +his "job" to definite size, and to the forms given by drawings, which +drawings should be made by the apprentice himself. When he is able to +do good work of this kind, he should attempt larger work, and the +construction of parts of structures involving exact fitting and special +manipulations. The course, finally, should conclude with exercises in +the construction and erection of complete structures and in the making +of peculiar details, such as are regarded by the average workman +as remarkable "_tours de force_." The trade school usually gives +instruction in the common school branches of education, and especially +in drawing, free-hand and mechanical, carrying them as far as the +successful prosecution of the trade requires. The higher mathematics, +and advanced courses in physics and chemistry, always taught in schools +of engineering, are not taught in the trade school, as a rule; although +introduced into those larger schools of this class in which the aim is +to train managers and proprietors, as well as workmen. This is done in +many European schools. + +As is seen above, the course of instruction in mechanical engineering +includes some trade education. The engineer is dependent upon the +machinist, the founder, the patternmaker, and other workers at the +trades, for the proper construction of the machinery and structures +designed by him. He is himself, in so far as he is an engineer, a +designer of constructions, not a constructor. He often combines, +however, the functions of the engineer, the builder, the manufacturer, +and the dealer, in his own person. No man can carry on, successfully, +any business in which he is not at home in every detail, and in which he +cannot instruct every subordinate, and cannot show every person employed +by him precisely what is wanted, and how the desired result can be best +attained. The engineer must, therefore, learn, as soon and as thoroughly +as possible, enough of the details of every art and trade, subsidiary +to his own department of engineering, to enable him to direct, with +intelligence and confidence, every operation that contributes to the +success of his work. The school of engineering should therefore be so +organized that the young engineer may be taught the elements of every +trade which is likely to find important application in his professional +work. It cannot be expected that time can be given him to make himself +an expert workman, or to acquire the special knowledge of details and +the thousand and one useful devices which are an important part of the +stock in trade of the skilled workman; but he may very quickly learn +enough to facilitate his own work greatly, and to enable him to learn +still more, with rapidity and ease, during his later professional life. +He must also, usually, learn the essential elements and principles of +each of several trades, and must study their relations to his work, and +the limitations of his methods of design and construction which they +always, to a greater or less extent, cause by their own practical or +economical limitations. He will find that his designs, his methods of +construction, and of fitting up and erecting, must always be planned +with an intelligent regard to the exigencies of the shop, as well as to +the aspect of the commercial side of every operation. This extension of +trade education for the engineer into several trades, instead of its +restriction to a single trade, as is the case in the regular trade +school, still further limits the range of his instruction in each. With +unusual talent for manipulation, he may acquire considerable knowledge +of all the subsidiary trades in a wonderfully short space of time, if he +is carefully handled by his instructors, who must evidently be experts, +each in his own trade. Even the average man who goes into such schools, +following his natural bent, may do well in the shop course, under good +arrangements as to time and character of instruction. If a man has not a +natural inclination for the business, and a natural aptitude for it, he +will make a great mistake if he goes into such a school with the hope of +doing creditable work, or of later attaining any desirable position in +the profession. + +The course of instruction, at the Stevens Institute of Technology, +includes instruction in the trades to the extent above indicated. The +original plan, as given below, included such a course of trade education +for the engineer; but it was not at once introduced. The funds +available from an endowment fund crippled by the levying of an enormous +"succession tax" by the United States government and by the cost of +needed apparatus and of unanticipated expenses, in buildings and in +organization, were insufficient to permit the complete organization +of this department. A few tools were gathered together; but skilled +mechanics could not be employed to take up the work of instruction in +the several courses. Little could therefore be done for several years in +this direction. In 1875 the writer organized a "mechanical laboratory," +with the purpose of attaining several very important objects: the +prosecution of scientific research in the various departments of +engineering work; the creation of an organization that should give +students an opportunity to learn the methods of research most usefully +employed in such investigations; the assistance of members of the +profession, and business organizations in the attempt to solve such +questions, involving scientific research, as are continually arising in +the course of business; the employment of students who had done +good work in their college course, when they so desire, in work of +investigation with a view to giving them such knowledge of this peculiar +line of work as should make them capable of directing such operations +elsewhere; and finally, but not least important of all, to secure, by +earning money in commercial work of this kind, the funds needed to carry +on those departments of the course in engineering that had been, up +to that time, less thoroughly organized than seemed desirable. This +"laboratory" was organized in 1875, the funds needed being obtained +by drawing upon loans offered by friends of the movement and by the +"Director." + +It was not until the year 1878, therefore, that it became possible to +attempt the organization of the shop course; and it was then only by the +writer assuming personal responsibility for its expenses that the plan +could be entered upon. As then organized--in the autumn of 1878--a +superintendent of the workshop had general direction of the trade +department of the school. He was instructed to submit to the writer +plans, in detail, for a regular course of shop instruction, and was +given as assistants a skilled mechanic of unusual experience and +ability, whose compensation was paid from the mechanical laboratory +funds, and guaranteed by the writer personally, and another aid whose +services were paid for partly by the Institute and partly as above. The +pay of the superintendent was similarly assured. This scheme had been +barely entered upon when the illness of the writer compelled him to +temporarily give up his work, and the direction of the new organization +fell into other hands, although the department was carried on, as above, +for a year or more after this event occurred. + +The plan did not fall through; the course of instruction was +incorporated into the college course, and its success was finally +assured by the growth of the school and a corresponding growth of its +income, and, especially, by the liberality of President Morton, who met +expenses to the amount of many thousands of dollars by drawing upon his +own bank account. The department was by him completely organized, with +an energetic head, and needed support was given in funds and by a force +of skilled instructors. This school is now in successful operation. +This course now also includes the systematic instruction of students in +experimental work, and the objects sought by the writer in the creation +of a "mechanical laboratory" are thus more fully attained than they +could have possibly been otherwise. It is to be hoped that, at +some future time, when the splendid bequest of Mr. Stevens may be +supplemented by gifts from other equally philanthropic and intelligent +friends of technical education, among the alumni of the school and +others, this germ of a trade school maybe developed into a complete +institution for instruction in the arts and trades of engineering, and +may thus be rendered vastly more useful by meeting the great want, in +this locality, of a real trade school, as well as fill the requirements +of the establishment of which it forms a part, by giving such trade +education as the engineer needs and can get time to acquire. + +The establishment of advanced courses of special instruction in +the principal branches of mechanical engineering may, if properly +"dovetailed" into the organization, be made a means of somewhat +relieving the pressure that must be expected to be felt in the attempt +to carry out such a course as is outlined below. The post-graduate +or other special departments of instruction, in which, for example, +railroad engineering, marine engineering, and the engineering of cotton, +woolen, or silk manufactures, are to be taught, may be so organized that +some of the lectures of the general course may be transferred to them, +and the instructors in the latter course thus relieved, while the +subjects so taught, being treated by specialists, may be developed more +efficiently and more economically. + +Outlines of these advanced courses, as well as of the courses in trade +instruction comprehended in the full scheme of mechanical engineering +courses laid out by the writer a dozen years ago, and as since recast, +might be here given, but their presentation would occupy too much space, +and they are for the present omitted. + +The course of instruction in this branch of engineering, at the Stevens +Institute of Technology, is supplemented by "Inspection Tours," which +are undertaken by the graduating class toward the close of the last +year, under the guidance of their instructors, in which expeditions they +make the round of the leading shops in the country, within a radius of +several hundred miles, often, and thus get an idea of what is meant by +real business, and obtain some notion of the extent of the field of work +into which they are about to enter, as well as of the importance of +that work and the standing of their profession among the others of the +learned professions with which that of engineering has now come to be +classed. + +At the close of the course of instruction, as originally proposed, and +as now carried out, the student prepares a "graduating thesis," in which +he is expected to show good evidence that he has profited well by the +opportunities which have been given him to secure a good professional +education. These theses are papers of, usually, considerable extent, and +are written upon subjects chosen by the student himself, either with or +without consultation with the instructor. The most valuable of +these productions are those which present the results of original +investigations of problems arising in practice or scientific research +in lines bearing upon the work of the engineer. In many cases, the +work thus done has been found to be of very great value, supplying +information greatly needed in certain departments, and which had +previously been entirely wanting, or only partially and unsatisfactorily +given by authorities. Other theses of great value present a systematic +outline of existing knowledge of some subject which had never before +been brought into useful form, or made in any way accessible to the +practitioner. In nearly all cases, the student is led to make the +investigation by the bent of his own mind, or by the desire to do work +that may be of service to him in the practice of his profession. All +theses are expected to be made complete and satisfactory to the head +of department of Engineering before his signature is appended to the +diploma which is finally issued to the graduating student. These +preliminaries being completed, and the examinations having been reported +as in all respects satisfactory, the degree of Mechanical Engineer is +conferred upon the aspirant, and he is thus formally inducted into the +ranks of the profession. + + +COURSE OF INSTRUCTION IN MECHANICAL ENGINEERING. + + +Robert H. Thurston--July, 1871. + +I. + +MATERIALS USED IN ENGINEERING.--Classification, Origin, and Preparation +(where not given in course of Technical Chemistry), Uses, Cost. + +_Strength and Elasticity_.--Theory (with experimental illustrations), +reviewed, and tensile, transverse and torsional resistance determined. + +_Forms_ of greatest strength determined. _Testing_ materials. + +_Applications_.--Foundations, Framing in wood and metal. + +FRICTION.--Discussion from Rational Mechanics, reviewed and extended. + +_Lubricants_ treated with materials above. + +Experimental determination of "coefficients of friction." + +II. + +TOOLS.--Forms for working wood and metals. Principles involved in their +use. + +Principles of pattern making, moulding, smith and machinists' work so +far as they modify design. + +Exercises in Workshops in mechanical manipulation. + +Estimates of _cost_ (stock and labor). + +MACHINERY AND MILL WORK.--Theory of machines. Construction. Kinematics +applied. Stresses, calculated and traced. Work of machines. Selection +of materials for the several parts. Determination of _proportions_ of +details, and of _forms_ as modified by difficulties of construction. + +Regulators, Dynamometers, Pneumatic and Hydraulic machinery. Determining +_moduli_ of machines. + +POWER, transmission by gearing, belting, water, compressed air, etc. + +LOADS, transportation. + +III. + +HISTORY AND PRESENT FORMS OF THE PRIME MOVERS. + +_Windmills_, their theory, construction, and application. + +_Water Wheels_. Theory, construction, application, testing, and +comparison of principal types. + +_Air, Gas, and Electric Engines_, similarly treated. + +STEAM ENGINES.--Classification. [Marine (merchant) Engine assumed as +representative type.] Theory. Construction, including general design, +form and proportion of details. + +_Boilers_ similarly considered. Estimates of _cost_. + +_Comparison_ of principal types of Engines and Boilers. Management and +repairing. Testing and recording performance. + +IV. + +MOTORS APPLIED to Mills. Estimation of required power and of _cost_. + +Railroads. Study of Railroad machinery. + +Ships. Structure of Iron Ships and rudiments of Naval architecture and +Ship propulsion. + +PLANNING Machine shops, Boiler shops, Foundries, and manufactories of +textile fabrics. Estimating _cost_. + +LECTURES BY EXPERTS. + +GENERAL SUMMARY of principal facts, and natural laws, upon the thorough +knowledge of which successful practice is based; and general _resume_ +of principles of business which must be familiar to the practicing +engineer. + +V. + +GRADUATING THESES. + +GRADUATION. + +Accompanying the above are courses of instruction in higher mathematics, +graphics, physics, chemistry, and the modern languages and literatures. + + * * * * * + + + + +IMPROVED DOUBLE BOILER. + + +The operation of boiling substances under pressure with more or less +dilute sulphuric or sulphurous acid forms a necessary stage of several +important manufactures, such as the production of paper from wood, the +extraction of sugar, etc. A serious difficulty attending this process +arises from the destructive action of the acid upon the boiler or +chamber in which the operation is carried on, and as this vessel, which +is generally of large dimensions, is exposed to considerable pressures, +it is necessarily constructed of iron or some other sufficiently +resisting metal. An ingenious method of avoiding this difficulty has +been devised, we believe in Germany, and has been put into practice with +a certain amount of success. It consists in lining the iron boiler with +a covering of lead, caused by fusion to unite firmly to the walls of the +boiler, and thus to protect it from the action of the acid. No trouble, +it is stated, is found to arise from the difference in expansion of the +two metals, which, moreover, adhere fairly well; but, on the other hand, +we believe it does actually occur that the repairs to this lead lining +are numerous, tedious, and costly of execution, so that the system can +scarcely be regarded as meeting the requirements of the manufacturer. +It is to secure all the advantages possessed by a lead-lined vessel, +without the drawback of frequent and expensive repairs, that the +digester, of which we annex illustrations, has been devised by Mr. +George Knowles, of Billiter House, Billiter Street. It consists of a +closed iron cylindrical vessel suitable for boiling under pressure, and +containing a second vessel open at the top, and of such a diameter as to +leave an annular space between it and the walls of the outer shell. This +inner receiver, which may be made of lead, glass, pottery, or any +other suitable material, contains the substance to be treated and the +sulphurous acid or other solution in which it is to be boiled. The +annular space between the two vessels is filled with water to the same +level as the solution in the receiver, and the latter is provided with +suitable pipes or coils, in which steam is caused to circulate for +the purpose of raising the solution of the desired temperature, and +effecting the digesting process. At the same time any steam generated +collects in the upper part of the boiler, and maintains an equal +pressure within the whole apparatus. Figs. 1 to 3 show the arrangement +clearly. Within the boiler, a, is placed the receiver, b, of pottery, +lead, or other material, leaving an annular space between it and the +boiler; this space is filled with water. The receiver, b, is furnished +with a series of pipes, in which steam or hot water circulates, to heat +the charge to the desired temperature. These pipes may be arranged +either in coils, as shown at d, Fig. 1, or vertically at d, Fig. 3. The +latter are provided with inner return pipes, so that any condensed water +accumulating at the bottom may be forced up the inner pipes by the +steam pressure and escape at the top. The vessel is charged through the +manhole, e, and the hopper, c, provided with a perforated cover, and is +discharged at the bottom by the valve, f, shown in Figs. 2 and 3. The +upper part of the boiler serves as a steam dome, and the pressure on the +liquid in the receiver and on the water in the annular space is thereby +maintained uniform. The necessary fittings for showing the pressure +in the vessel, water level indicator, safety valve, cocks for testing +solutions, etc., are of course added to the apparatus, but are not +indicated in the drawing. The arrangement appears to us to possess +considerable merit, and we shall refer to it again on another occasion, +after experiments have been made to test its efficiency.--_Engineering_. + +[Illustration: IMPROVED DOUBLE BOILER.] + + * * * * * + + + + +THE GARDNER MACHINE GUN. + + +[Illustration: FIG. 1.--SINGLE BARREL GARDNER MACHINE GUN.] + +The mechanism by which the various functions of loading, firing, and +extracting are performed is contained in a rectangular gun metal case, +varying in dimensions with the number of barrels in the arm. In the +single barrel gun the size of this case is 14 inches in length, 5½ +inches in depth, and 2½ inches in width. The top of the box is hinged, +so that easy access can be had to the mechanism, which consists of a +lock, the cartridge carrier, and the devices for actuating them. In the +multiple barrel guns, the frames which, with the transverse bar at the +end, hold the barrels in place, form the sides of the mechanism chamber, +in the front end of which the barrels are screwed. The mechanism is +actuated by a cam shaft worked by a hand crank on one side of the +chamber. By this means the locks are driven backward and forward, +the latter motion forcing the cartridges into place, and the former +withdrawing the empty cartridge case after firing. The extractor hook +pivoted to the lock plunger rises, as the lock advances, over the rim of +the case, but is rigid as the lock is withdrawn, so that the action is +a positive one. The cartridges, which are contained in a suitable +frame attached to the forward part of the breech chamber, pass through +openings in the top plate of the latter, an efficient distribution being +secured by means of a valve having a transverse motion. Each cartridge +as it falls is brought into the axis of the barrel and the plunger, +while the advance motion of the lock forces them into position. In the +five-barrel gun illustrated by Fig. 3 the cartridge feeder contains 100 +cartridges, in five Vertical rows of 20 cartridges each, and these are +kept supplied, when firing, from supplementary holders. Fig. 1 shows the +portable rest manufactured by the Gardner Gun Company. It consists of +two wrought iron tubes, placed at right angles to each other; the front +bar can be easily unlocked, and placed in line with the trail bar, from +which project two arms, each provided with a screw that serves for the +lateral adjustment of the gun. These screws are so arranged as to allow +for an oscillating motion of the gun through any distance up to 15 deg. +The tripod mounting, used for naval as well as land purposes, is shown +in Fig. 2, which illustrates the two barrel gun complete. The five +barrel gun, Fig. 3, is shown mounted on a similar tripod. The length of +this weapon over all is 53.5 inches, the barrels (Henry system) are 33 +inches long, with seven grooves of a uniform twist of one turn in 22 +inches. + +[Illustration: Fig. 2.--TWO BARREL GARDNER GUN.] + +Gardener's five barrel gun in the course of one of the trials fired +16,754 rounds with only 24 jams, and in rapid firing reached a maximum +of 330 shots in 30 seconds. The two barrel gun fired 6,929 rounds +without any jam; the last 3,000 being in 11 minutes 39 seconds, without +any cleaning or oiling.--_Engineering_. + +[Illustration: Fig. 3.--FIVE BARREL GARDNER GUN.] + + * * * * * + + + + +CLIMBING TRICYCLES. + + +The cycle trade is one which has been developed with great rapidity +within the last ten years, and, like all new industries, has called +forth a considerable amount of ingenuity and skill on the part of those +engaged in it. We cannot help thinking, however, that much of this +ingenuity has been misplaced, and that instead of striving after new +forms involving considerable complication and weight, it would have +been better and more profitable if manufacturers had moderated their +aspirations, and aimed at greater simplicity of design; for it must +be remembered that cyclists are, as a rule, without the slightest +mechanical knowledge, while the machines themselves are subject to very +hard usage and considerable wear and tear in traveling over the +ordinary roads in this country. We refer, of course, more especially to +tricycles, which in one form or another are fast taking the place of +bicycles, and which promise to assume an important position in every +day locomotion. Hitherto one of the chief objections to the use of the +tricycle has been the great difficulty experienced in climbing hills, a +very slight ascent being sufficient to tax the powers of the rider to +such an extent as to induce if not compel him in most instances to +dismount and wheel his machine along by hand until more favorable ground +is reached. To obviate this inconvenience many makers have introduced +some arrangement of gearing speeds of two powers giving the necessary +variation for traveling up hill and on the level. We noticed, however, +one machine at the exhibition which seemed to give all that could be +desired without any gearing or chains at all. This was a direct action +tricycle shown by the National Cycle Company, of Coventry, in which the +pressure from the foot is made to bear directly upon the main axle, and +so transmitted without loss to the driving wheels on each side, the +position of the rider being arranged so that just sufficient load is +allowed to fall on the back wheel as to obtain certainty in steerage. +The weight of this machine is much less than when gearing is used, and +the friction is also considerably reduced, trials with the dynamometer +having shown that on a level, smooth road, a pull of 1 lb. readily +moved it, while with a rider in the seat 4 lb. was sufficient. On this +tricycle any ordinary hill can, it is stated, be ascended with great +ease, and as a proof of its power it was exhibited at the Stanley show +climbing over a piece of wood 8 in. high, without any momentum whatever. +We understand that at the works at Coventry a flight of stairs has been +erected, and that no difficulty is experienced in ascending them on one +of these machines.--_The Engineer_. + + * * * * * + + + + +SUBMARINE EXPLORATIONS. + +VOYAGE OF THE TALISMAN. + + +It was but a few years ago that the idea was prevalent that the seas at +great depths were immense solitudes where life exhibited itself under no +form, and where an eternal night reigned. To-day, thanks to expeditions +undertaken for the purpose of exploring the abysses of the ocean, we +know that life manifests itself abundantly over the bottom, and that +at a depth of five and six thousand meters light is distributed by +innumerable phosphorescent animals. Different nations have endeavored to +rival each other in the effort to effect these important discoveries, +and several scientific missions have been sent to different points of +the globe by the English and American governments. The French likewise +have entered with enthusiasm upon this new line of research, and for +four consecutive years, thanks to the devoted aid of the ministry of the +marine, savants have been enabled to take passage in government vessels +that were especially arranged for making submarine explorations. + +[Illustration: THE FRENCH SCIENTIFIC STEAMER TALISMAN.] + +The first French exploration, which was an experimental trip, was made +in 1880 by the Travailleur in the Gulf of Gascogne. Its unhoped +for results had so great an importance that the following year the +government decided to continue its researches, and the Travailleur was +again put at the disposal of Mr. Alph. Milne Edwards and the commission +over which he presided. Mr. Edwards traversed the Gulf of Gascogne, +visited the coast of Portugal, crossed the Strait of Gibraltar, and +explored a great portion of the Mediterranean. In 1882 the same vessel +undertook a third mission to the Atlantic Ocean, and as far as to the +Canary Islands. The Travailleur, however, being a side-wheel advice-boat +designed for doing service at the port of Rochefort, presented none +of those qualities that are requisite for performing voyages that are +necessarily of long duration. The quantity of coal that could be stored +away in her bunkers was consumed in a week, and, after that, she could +not sail far from the points where it was possible for her to coal up +again. So after her return Mr. Edwards made a request for a ship that +was larger, a good sailer, and that was capable of carrying with it a +sufficient supply of fuel for remaining a long time at sea, and that +was adapted to submarine researches. The Commission indorsed this +application, and the Minister of Instruction received it and transmitted +it to Admiral Jauréguiberry--the Minister of the Marine--who at once +gave orders that the Talisman should be fitted up and put in commission +for the new dredging expedition. This vessel, under command of Captain +Parfait, who the preceding year had occupied the same position on the +Travailleur, left the port of Rochefort on the 1st of June, 1883, having +on board Mr. Milne Edwards and the scientific commission that had been +appointed by the Minister of Public Instruction. The Talisman explored +the coasts of Portugal and Morocco, visited the Canary and Cape Verd +Islands, traversed the Sea of Sargasso, and, after a stay of some time +at the Azores, returned to France, after exploring on its way the Gulf +of Gascogne (Fig.). + +[Illustration: FIG.1.--CHART OF THE TALISMAN'S VOYAGE.] + +The magnificent collections in natural history that were collected +on this cruise, and during those of preceding years made by the +Travailleur, are, in a few days, to be exhibited at the Museum of +Natural History. We think we shall be doing a service to the readers of +this journal, in giving them some details as to the organization of the +Talisman expedition as well as to the manner in which the dredgings were +performed. + +[Illustration: FIG.2.--PLAN OF THE VESSEL.] + +The vessel, as shown by her plan in Fig. 2, had to undergo important +alterations for the cruise that she was to undertake. Her deck was +almost completely freed from artillery, since this would have encumbered +her too much. Immediately behind the bridge, in the center of the +vessel, there were placed two windlasses, one, A, to the right, and the +other, B, to the left (Fig. 2). These machines, whose mode of operation +will be explained further along, were to serve for raising and lowering +the fishing apparatus. A little further back there were constructed +two cabins, G and HH. The first of these was designed to serve as a +laboratory, and the second was arranged as quarters for the members of +the mission. + +The sounding apparatus, the Brothergood engine for actuating it, and the +electric light apparatus were placed upon the bridge. The operating +of the sounding line and of the electric light was therefore entirely +independent of that of the dredges. On the foremast, at a height of +about two meters, there was placed a crane, F, which was capable of +moving according to a horizontal plane. Its apex, as may be seen from +the plan of the boat, was capable of projecting beyond the sides of the +ship, to the left and right. To this apex was fixed a pulley over which +ran the cable that supported the dredges or bag-nets, which latter were +thus carried over the boat's sides. + +[Illustration: FIG.3.--DIAGRAM OF THE THIBAUDIER SOUNDING APPARATUS.] + +The preliminary operation in every submarine exploration consists in +exactly determining the depth of the sea immediately beneath the vessel. +To effect this object different sounding apparatus have been proposed. +As the trials that were made of these had shown that each of them +possessed quite grave defects, Mr. Thibaudier, an engineer of the navy, +installed on board the Talisman last year a new sounding apparatus which +had been constructed according to directions of his and which have given +results that are marvelous. The apparatus automatically registers the +number of meters of wire that is paid out, and as soon as the sounding +lead touches bottom, it at once stops of itself. This apparatus is shown +in Fig. 4, and a diagram of it is given in Fig. 3, so that its operation +may be better understood. The Thibaudier sounding apparatus consists of +a pulley, P (Fig. 3), over which is wound 10,000 meters of steel wire +one millimeter in diameter. From this pulley, the wire runs over a +pulley, B, exactly one meter in circumference; from thence it runs to a +carriage, A, which is movable along wooden shears, runs up over a fixed +pulley, K, and reaches the sounding lead, S, after traversing a guide, +g, where there is a small sheave upon which it can bear, whatever be the +inclination of the boat. The wheel, B, carries upon its axle an endless +screw that sets in motion two toothed wheels that indicate the number +of revolutions that it is making. One of these marks the units and the +other the hundredths (Fig. 5). This last is graduated up to 10,000 +meters. As every revolution of the wheel, B, corresponds to one meter, +the number indicated by the counter represents the depth. Upon the axle +of the winding pulley there is a break pulley, p. The brake, f, is +maneuvered by a lever, L, at whose extremity there is a cord, C, which +is made fast to the carriage, A. When, during the motions due to +rolling, the tension of the steel wire that supports the lead diminishes +or increases, the carriage slightly rises or falls, and, during these +motions, acts more or less upon the brake and consequently regulates the +velocity with which the wire unwinds. When the lead touches bottom, the +wire, being suddenly relieved from all weight (which is sometimes as +much as 70 kilos), instantly stops. + +[Illustration: FIG. 4.--GENERAL VIEW OF THE SOUNDING APPARATUS IN THE +"TALISMAN:"] + +The maneuver of this apparatus may be readily understood. The apparatus +and its weights are arranged in the interior of the vessel. A man bears +upon the lever, L (Fig. 3), and the counter is set at zero. All being +thus arranged, the man lets go of the break, and the unwinding then +proceeds until the lead has touched bottom. During the operation of +sounding, the boat is kept immovable by means of its engine, so that the +wire shall remain as vertical as possible. The bottom being reached, the +unwinding suddenly ceases, and there is nothing further to do but read +the indication given by the differential counter, this giving the depth. + +[Illustration: FIG. 5.--APPARATUS FOR MEASURING THE LENGTH OF THE WIRE +PAID OUT.] + +Near the winding pulley, there is a small auxiliary engine, M, which +is then geared with the axle of the said pulley, and which raises the +sounding apparatus that has been freed from its weight by a method that +will be described further along. + +We have endeavored in Fig. 4 to show the aspect of the bridge at the +moment when a sounding was about being made. From this engraving (made +from a photograph) our readers may obtain a clear idea of the Thibaudier +sounding apparatus, and understand how the wheel over which the wire +runs is set in motion by the Brothergood engine.--_La Nature_. + + * * * * * + + + + +CABLE GRAPNEL. + + +Some improvements have recently been made by Mr. Alexander Glegg and the +inventor in the well-known Jamieson grapnel used for raising submerged +submarine cables. The chief feature of the grapnel is that the flukes, +being jointed at the socket, bend back against a spring when they catch +a rock, until the grapnel clears the obstruction, but allow the cable +to run home to the crutch between the fluke and base, as shown in the +figures. In the older form the cable was liable to get jammed, and cut +between the fixed toe or fluke and the longer fluke jointed into it. +This is now avoided by embracing the short fluke within the longer one. +The shank, formerly screwed into the boss, is now pushed through and +kept up against the collar of the boss, by the volute spring, which at +the same time presses back the hinged flukes after being displaced by +a rock. The shank can now freely swivel round, whereas before it was +rigidly fixed. The toes or flukes are now made of soft cast steel, which +can be straightened if bent, and the boss is made of cast steel or +gun-metal. + +[Illustration: JAMIESON'S GRAPNEL.] + + * * * * * + + + + +WRETCHED BOILERMAKING. + + +_To the Editor of the Scientific American_: + +As long as I have been a reader of the SCIENTIFIC AMERICAN I have been +pleased with the manner in which you investigate and explain the cause +of any boiler explosion which comes to your knowledge; and I have +rejoiced when you heaped merited censure upon the fraudulent +boilermaker. In your paper in December last you copied a short article +on "Conscience in Boilermaking," in which the writer, after speaking +of the tricks of the boilermaker in using thinner iron for the center +sheets than for the others, and in "upsetting" the edges of the plates +to make them appear thicker, goes on to say: "We call attention to this, +because the discovery of such practice has made serious trouble between +the boilermaker and the steam user. We would not believe that there were +men so blind to the duties and obligations which rest upon them as +to resort to such practice, but the careful inspector finds all such +defects, and in time we come to know whose work is carefully and +honestly done, and whose is open to suspicion. In States and cities +where inspection laws are in force that give the methods and rules by +which the safe working pressure of a boiler is calculated, there is no +alternative except to follow the rules; and if certain requirements +regarding construction are a part of the law, there is no authority or +right to depart from it, and yet there are boilermakers who try to force +their boilers into such localities when their work is not up to the +requirements of the law." + +Now, if some boilermakers are so dishonest as to try and impose upon the +locomotive engineer, who they know will carefully examine every part of +his boiler, and who is able to detect any flaw, it is not to be expected +that the farmer will escape. Nor does he. The great number of explosions +of boilers used in thrashing and in other farm work proves that there +are boilermakers who "force their boilers into such localities +when their work is not up to the requirements of the law." And the +boilermaker, if he be dishonest, is doubly tempted if the broad width of +a continent intervenes between him and the farmer for whom his work is +intended, and if in the place where the boiler is to be used there are +no inspection laws in force. The farmer who lives many miles from a +city, and who has no means of testing any boiler he may purchase, +is wholly at the mercy of the boilermaker, and must run it until it +explodes or time proves it to have been honestly made. Then, again, +there are boilermakers who, although making boilers of good iron and of +the proper thickness, finish them off so badly that the farmer is put to +great inconvenience and expense to put them in working order. Two years +ago I purchased a straw-burning engine and boiler made by an Eastern +firm. Before it had run ten days the boiler began to leak at the +saddle-bolt holes. The engineer tightened the nuts as far as possible, +but could not stop the leaks, which at last became so bad that we had to +stop work and take the engine to the shop. Upon taking off the saddle +and taking out the bolts it was discovered that they were too small for +the holes in the boiler, and that they had been wrapped with candle wick +and white lead to make them fill the holes, and that a light washer had +been put on each bolt between the head and the inside of the boiler. +This washer kept the lead in its place, and prevented the boiler from +showing a leak when first fired up. The water pipes in the fire-box soon +gave out and became utterly useless. Upon inquiring of the patentee of +this straw-burning device, who was supposed to have put it in my boiler, +he stated that he had had nothing to do with it, but that it was put in +by the firm selling these engines, and "as cheaply as possible." Before +I got this boiler and engine in fair running order I had spent hundreds +of dollars and had to do entirely away with the water grates. + +Last summer, needing another tharshing engine, I was induced to buy +one of the same make as my old one, but with a different straw-burning +device. The firm who sold it to me agreed that it should have none of +the faults of the old one. Well, I got it, and, upon hauling it out to +my ranch, and getting up steam, I found it to be much worse than the +first one I had bought. The boiler leaked at nearly every hole where +a tap had been screwed into it. It took an engineer, a boilermaker, a +blacksmith, and a fireman several days to get it in shape so that we +could use it at all; and after we did start up, the boilermaker had +to be sent for several times to stop new leaks that were continually +showing themselves. + +I send you by this mail for your inspection one of the saddle bolts and +one of the bolts taken out of the piston, and also the certificates of +the engineer, boilermaker, and machinist who repaired the boiler. In +justice to my fellow-farmers I ought to publish these certificates and +the names of these boilermakers to the world, but, for the present at +least, I refrain from so doing. These boilermakers will see this article +and they will know, if the public does not, for whom it is intended. If +it has the effect of making them exercise more care in the construction +and fitting up of their engines and boilers, I have not written in vain. + +D. FREEMAN. + +Los Angeles, Cal., March 7,1884. + +[The two bolts and the certificates above referred to accompany the +letter of Mr. Freeman. We can only wonder how it was that, after having +been treated as he relates in the first instance, he should have had any +further business with parties who would send out such boilers, for the +testimony of the engineer and workmen make the case even stronger than +Mr. Freeman has put it.--ED.] + + * * * * * + + + + +A THREADED SET COLLAR. + + +There are cases where a long screw must be rotated with a traversing nut +or other threaded piece traveling on its thread a limited and variable +distance. At one time the threaded nut or piece may be required to +go almost the entire length of the screw, and at another time a much +shorter traverse would be required. In many instances the use of side +check nuts is inconvenient, and in some it is impossible. One way of +utilizing the nut as a set collar is to drill through its side for a set +screw, place it on its screw, pour a little melted Babbitt metal, or +drop a short, cold plug of it into the hole, tap the hole, and the tap +will force the Babbitt into the threads. + +Insert the set screw, and when it acts on the Babbitt metal it will +force it with great friction on to the thread without injuring the +thread; and when the set screw tension is released, the nut turns +freely. A similar and perhaps a better result may be obtained by +slotting the hole through the nut as though for the reception of a key. +Secure a key (preferably of the same material as the nut) by slight +upsetting at its ends, and then thread the nut, key, and all. Place +a set screw through the nut over the threaded key, and the job is +complete. + + * * * * * + + + + +PNEUMATIC MALTING. + + +The lethargy in the malting trade, and in all matters relating to +malting processes, induced by two centuries of restrictive legislation, +is being gradually shaken off by the malting industry under the new law. +For many years nearly all improvements in malting processes originated +abroad, as numberless Acts of Parliament fettered every process and the +use of every implement requisite in a malt-house in this country. The +entire removal of these legislative restrictions gives an opportunity +for improved processes, which promises to open up a considerable +field for engineering work, and to develop a very backward art by the +application of scientific principles. The present time is, therefore, +one of more material change than malting has ever experienced. + +[Illustration: PNEUMATIC MALTING AT TROYES. Fig. 1.] + +Of the numerous improvements effected in the past few years, those made +by M. Galland in France, and more recently by M. Saladin, are by far the +most prominent. M. Galland originated what is known as the pneumatic +system eight or nine years ago. This system is carried out at the +Maxéville brewery, near Nancy. + +[Illustration: PNEUMATIC MALTING AT TROYES. Fig. 2.] + +Since that time further improvements have been made by M. Galland; but +more recently great advances have been made in the system by M. +Saladin. He has developed the practice of the leading principle, and in +conjunction with Mr. H. Stopes, of London, has added improved kilns and +various mechanical apparatus for performing the work previously done by +hand. He has also devised a very ingenious machine for cooling the moist +air by which the process is carried on. + +[Illustration: FIG. 4.--ECHANGEUR AND TURNING MACHINE.] + +At the recent Brewery Exhibition, some of the machinery used in these +new maltings was shown in action by Messrs. H. Stopes & Co., together +with drawings of a malting constructed at Troyes for M. Bonnette under +M. Saladin's instructions. This malting is the third constructed for the +same firm, the others being at Nancy. That at Troyes we now illustrate. +We will not occupy space by a general description of the pneumatic +system, one great feature in which is the continuous manufacture of malt +throughout the year instead of only from five to eight months of the +year, as it will be gathered from the following description of the +Troyes malting: + +[Illustration: FIG. 5.--ECHANGEUR, AXIAL SECTION.] + +In our engravings, Figs. 1, 2, and 3, the letter A indicates the +germinating cases; B, Saladin's patent turning screws; C A, air +channels; D, passages; E R, main driving shafts; e, pulleys; F, metal +recesses to fit turning screws; G, elevators; H, trap doors; I, air +channels; J, openings to growing floor for air; K S, engines and fan +room; L N, fans, supply and exhaust; T, boiler; U, chimney; f, well. The +capacity of the malting is 130 qr. malt every day. This is equivalent to +an English house of 520 qr. steep. The whole space occupied is the area +necessary for kilns, malt and barley stores, engine and boiler house, +and fans. No additional area is required for germinating floors, as ten +germinating cases, A, are placed in the basement below the kilns and +stores. The building is of brick, with the internal walls below the +ground line resting upon cast iron columns and rolled joists. The +germinating cases, A A, are of iron; the bottoms are double. One of +perforated plate is placed 6 inches above the bottom. These plates admit +of draining the corn if the germinating case is used as a steeping +cistern also. Their chief object is, however to admit of ready +circulation of the air by the means presently to be described. Large +channels, A a, serve as drains for moisture and to convey the air to or +from the growing corn. Between each case is a passage, D, enabling the +maltster to have free access to the corn at all points. + +[Illustration: FIG. 6.--ECHANGEUR TRANSVERSE SECTION.] + +With the exception of the driving shaft, E, all the machinery is in +duplicate, so that the possibility is remote of any breakdown that would +seriously affect the working of the house. This is necessary, as should +the fans, L N, be stopped for twenty-four hours the corn germinating +at a depth exceeding 30 inches would heat and impair its vitality. The +boilers, T, and engines, S, are of the common type of 20 horse power +nominal. The fans, L N, are the Farcot patent, illustrated a short time +since in our pages. The lower floors of the kilns are provided with +the Schlemmer patent mechanical turners. The turners, Fig. 4, in the +germinating cases are Saladin's patent. + +[Illustration: FIG. 7.--ECHANGEUR, SECTIONAL PLAN.] + +The germination of the grain is effected by means of cool moist air +provided by the fan described and the cooler and moistener--Figs. 5, 6, +and 7, herewith--known as an _echangeur_. As the germinating grain has +a depth of from 30 inches to 40 inches some pressure is required, and +mechanical means are necessary for efficient and economical turning. +The _echangeur_ is a very ingenious application of the well understood +rapidity of evaporation of any liquid when spread out in very thin +layers over large surfaces and exposed to a current of air. It consists +of a cylinder, or series of cylinders, of increasing diameter, placed +one within another. Each consists of finely perforated sheet iron. They +are placed in a trough of water, just sufficiently immersed to insure +complete wetting. When rotated at a slow speed, the surfaces of all the +cylinders are kept just wetted. A volume of air is either driven or +drawn through, as may be required for any particular purpose. In the +model malting, as shown at Fig. 4, taken from that shown at the Brewery +Exhibition, the air was driven through the _echangeur_ and thence +through the germinating barley. Here or as employed in the malting +illustrated, the air in its passage comes first into contact with the +moistened cylinders, and if hot and dry it becomes moist and cool, for +the constant evaporation upon the cylinders has a very considerable +refrigerating effect. + +This was well known to the Egyptians over four thousand years ago, and +the porous bottle--_gergeleh_--of Esnch has been made until the present +day, to keep the drinking water cool and fresh. The _echangeur_ is +like a gigantic gergeleh, and by increasing the size and number of the +cylinders, and causing the water in the moistening trough to circulate, +any volume of air can be wetted to the saturation limit corresponding to +its temperature. It will be seen that this apparatus gives the maltster +complete control of the humidity and heat as well as volume of the air +driven through germinating corn. + +[Illustration: Fig. 8.] + +The turning apparatus is shown by Fig. 4, and consists, as will be seen, +of a cylindrical frame provided with rollers which run on rails at the +edge of the germinating cases. It is carried to and fro from either end +of the case by compensating rope gearing which at the same time gives +motion to the gearing actuating the turning screws. These screws do not +quite touch the bottom of the germinating case, but are provided with a +pair of small brushes, as shown in the annexed engraving, Fig. 8, which +just skim it. The apparatus shown has but three of these screws, but the +cases are generally made wide enough for six. The kilns are double, +each possessing two floors, and worked upon the Stopes' system. The +construction of the furnaces is of the ordinary French pattern. The +arrangement of the house permits of great regularity in working. Every +day 130 qrs. of barley is screened, sorted, cleaned, and passed into a +steeping cistern. When sufficiently steeped it runs through piping into +the germinating case, which, in the natural order of working, is empty. +Here it forms the couch. When it is desirable to open couch a small +amount of air is forced through the grain by opening the trap door +connected with the main air channel. This furnishes the growing corn +with oxygen, removes the carbonic acid gas, and regulates temperatures +of the mass of grain. Later the Saladin turner is put in motion about +every eight to twelve hours. The screws in rotating upon their axes are +slowly propelled horizontally. They thus effectually turn the grain and +leave it perfectly smooth. This turning prevents matting of the roots, +the regulation of temperature and exposure to air being effected +by means of the cold air from the _echangeur_. When the grain is +sufficiently grown it is elevated to the kilns. For forty hours it +remains upon the top floor. It is then dropped upon the bottom floor, a +further charge of green corn following upon the top floor. The benefit +is mutual. The bottom floor is maintained at an even temperature, being +virtually plunged in an air bath; free radiation of heat is prevented; +the top surface of the malt is necessarily nearly as warm as that next +the wires, which in its turn is subject to lower heats than would be +necessary if free radiation from the surface was allowed. The top floor +is by the intervention of the layer of malt between it and the fire +prevented it from coming into direct contact with heat of a dangerous +and damaging degree. The same heat which is used to dry one floor, and +in an ordinary kiln passes at once into the air as waste, is the best +possible description of heat, namely, very slightly moistened heated +air, to remove the moisture from the second layer of malt at a low +temperature. It is of vital importance to retain this green malt at a +low heat so long as any percentage of moisture exceeding, say, 15 per +cent, is retained by the corn. + +The regulation of temperature is shown by the diagrams, Figs. 9 and 10: + +[Illustration: Fig. 9.] + +[Illustration: Fig. 10.] + +The distribution of the heated air in the kiln is rarely as uniform as +is supposed, the temperature of the malt on drying floor being very +different at different parts. In illustration of this, the following may +be taken from a statement by Mr. Stopes of the results of an examination +of the temperatures at different parts of a drying floor in a kiln in +Norfolk: "A malting steeping 105 qr. every four days has a kiln 75 +feet by 36 feet; an average drying area of under 26 feet per qr. The +consequent depth of green malt when loaded is over 10 inches. The total +area of air inlets is less than 27 feet super. The air outlet exceeds +117 feet, a ratio of 13 to 3. The capacity of head room equals 44,550 +feet cube. The area of each tile is 144 inches, with 546 holes, giving +an effective air area of some 32 inches. The ratio of non-effective +metallic surface to air space is thus 9 to 2." The Casella anemometer +gave no indications at several points, and fluctuating up and down +draughts were observable at many others, especially at two corners and +along the center. "The strongest upward draught pulsated with the gusts +of wind and ranged from 30 feet to 54 feet per minute, a down draught of +equal intensity occurring at intervals at the same spot, notwithstanding +the fact that the air was rushing in at the inlets below the floor at +the high velocity of 785 feet per minute. The temperatures of the drying +malt and superimposed air consequent upon the conditions thus indicated +were naturally as follows: At B, the place supposed to be hottest: Heat +of malt touching tiles, 216 deg.; heat of malt 1 inch above tiles, 167 +deg.; heat of malt 3 inches above tiles 154 deg.; heat of malt 4 inches +above tiles, 152 deg.; heat of malt 5 inches above tiles, 142 deg.; heat +of malt on surface, 112 deg. At A, the place supposed to be coldest: +Heat of malt next tiles, 174 deg.; heat of malt 2 inches above tiles, +143 deg.; heat of malt 4 inches above tiles, 135 deg.; heat of malt on +surface, 104 deg.; the heat of the air 3 feet above tiles, 84 deg.; the +heat of the air 5 feet above tiles, 82 deg. Fig. 9 shows the temperature +at twenty-six points close to the tiles, taken with twelve registered +and accurate thermometers in the space of fifteen minutes." These and +other similar tests have led to the conclusion that the best malt drying +cannot be done on a single floor. + +Fig. 10 is a similar diagram showing the temperatures on a drying floor +of kiln at Poole, Dorset, altered to Stopes' system of drying. The +temperature at different depths of the drying grain was as follows: Malt +at surface of tiles, 142 deg.; malt at 1 inch above tiles, 142 deg.; +malt at 2 inches above tiles, 142 deg.; malt at 4 inches above tiles, +141 deg.; malt on surface, 140 deg. + +The advantages of the Saladin system over that hitherto working in +Britain are numerous, and are thus enumerated by Messrs. Stopes & Co. +who are agents for M. Saladin: The area occupied by the building does +not equal one-third of that otherwise required. The actual growing-floor +space is only about one-seventh, and the number of workmen is ruled +necessarily by the size of the house, but on an average is reduced +two-thirds; but the employment of much more power is necessary, and the +power is used at more frequent intervals. The use of plant and premises +is continuous, the processes of malting being equally well performed +during the summer months. The further advantage of this is that brewers +secure entire uniformity in age of malt. By the English system the +stocks of finished malt necessarily fluctuate largely. All grain is +subjected to the same conditions of surrounding air, exposure, and +temperature. The volume of air supplied to the germinating corn is +entirely under control, as are also its temperature and humidity. When +germination is arrested and the green malt is drying, the double kilns +insure control of the temperatures of the corn in the kilns. The +infrequency of turning the germinating grain benefits the growth of the +roots and the development of the plumule, besides saving much labor. No +grains are crushed or damaged by the feet or shovels of workmen. The air +supplied to the corn can be inexpensively freed from disease germs +and impurities. The capital needed for malting can be reduced by the +diminished cost of installation, and the reduced stocks of malt on hand. +The quality of the malt made is considerably improved. The percentages +of acidity are much reduced. The stability of the beer is increased, +and a greater percentage of the extractive matter of the barley is +obtainable by the brewer.--_The Engineer_. + + * * * * * + + + + +NON-SPARKING KEY. + + +Profs. Ayrton and Perry lately described and exhibited before the +Physical Society their new ammeters and voltmeters, also a non-sparking +key. The well known ammeters and voltmeters of the authors used for +electric light work are now constructed so as to dispense with +a constant, and give the readings in amperes and volts without +calculation. This is effected by constructing the instruments so +that there is a falling off in the controlling magnetic field, and a +considerable increase in the deflecting magnetic field. The deflections +are thus made proportional to the current or E.M.F. measured. The +ingenious device of a core or soft iron pole-piece, adjustable between +the poles of the horseshoe magnet, is used for this purpose. By means of +an ammeter and voltmeter used conjointly, the resistance of part of the +circuit, say a lamp or heated wire, can be got by Ohm's law. Profs. +Ayrton and Perry's non-sparking key is designed to prevent sparking with +large currents. It acts by introducing a series of resistance coils +determined experimentally one after the other in circuit, thereby +cutting off the spark. + + * * * * * + + + + +NEW INSTRUMENTS FOR MEASURING ELECTRIC CURRENTS AND ELECTRO-MOTIVE +FORCE. + +By Messrs. R. E. CROMPTON and GISBERT KAPP. + +[Footnote: Paper read before the Society of Telegraph Engineers, 14th +February, 1884.] + + +In consequence of the rapid development of that part of electrical +science which may be termed "heavy electrical engineering," reliable +measuring instruments specially suitable for the large currents +employed in lighting and transmission of energy have become an absolute +necessity. As usual, demand has stimulated supply, and many ingenious +and useful instruments have been invented, the manufacture of which +forms at the present day an important industry. Mr. Shoolbred, in a +paper which he recently read before this Society, gave a full and +interesting account of the labors of our predecessors in this field. +To-day we add to the list then given a class of instruments invented by +us, examples of which are now before you on the table. We have preferred +to call them current and potential indicators in preference to meters, +considering that the latter term, or rather termination, ought to be +applied rather to integrating instruments, which the necessities of +electric lighting, we believe, will soon bring into extensive use. The +principal aim in the design of these indicators has been to obtain +instruments which will not alter their calibration in consequence of +external disturbing forces. If this object can be attained, then it will +be possible to divide the scale of each instrument directly into amperes +or volts, as the cause may be, and thus avoid the use of a coefficient +of calibration by which the deflection has to be multiplied. This is an +important consideration when it is remembered that in many cases +these instruments have to be used by unskilled workmen, to whom a +multiplication involving the use of demical fractions is a tedious and +in some cases even an impossible task. + +[Illustration: FIG. 1. FIG. 2.] + +All measurements are comparative. We measure weights or forces by +comparison with some generally known and accepted unit standard +weights, lengths, areas, and volumes, by comparison with a unit length, +resistance by a standard ohm, and so forth. In the same way currents +could be measured by comparison with a standard current: but this +would be a troublesome process, not only on account of the apparatus +necessary, but also because it would be a matter of some difficulty to +have a standard current always ready for use. In general, measurement +by direct comparison with a standard unit is discarded for the more +indirect method of measuring not the current itself, but its chemical, +mechanical, or magnetic effect. The chemical method is very accurate if +a proper density of current through the surface of the electrodes be +used,[1] but since it requires a considerable time, and, above all, an +absolutely constant current, its use is almost entirely restricted +to laboratory work and to the calibration of other instruments. For +practical ready use, instruments employing the mechanical or magnetic +effect of the current are alone suitable. We weigh, so to speak, the +current against the force of a magnet, of a spring, or of gravity. +The measurement will be exact if the thing against which we weigh or +counterbalance the current itself retains its original standard value. +Where permanent magnets or springs are used as a balancing force, this +condition of constancy in our weights and measures is not always fully +maintained, and to make matters worse, there is no visible sign by which +a change, should it have occurred, can be readily detected. A spring +may have been overstrained or a steel magnet may have become weakened +without showing the least alteration in outward appearance. To overcome +this difficulty, the obvious remedy is not to use springs or steel +magnets at all, but to substitute for these some other force which +should be either absolutely constant, such as the force of gravity, or +at least should, vary only within narrow limits, and this in accordance +with a definite law. This latter condition can be fulfilled by the +employment of electro-magnets. + +[Footnote 1: According to recent experiments made by Dr. Hammerl, the +density of current in a copper voltameter should be half an ampere per +square inch of surface.] + +[Illustration: FIG 3.] + +To imitate with an electro magnet as nearly as possible a permanent +magnet, so that the former can be used to replace the latter, it is +necessary that the magnetism in the iron core should remain constant. +This could, of course, be done by exciting the electro magnet with a +constant current from a separate source. (In a recent note to the Paris +Academy of Science, M.E. Ducretet described a galvanometer with steel +magnet, which is surrounded by an exciting coil. When recalibration +appears necessary, a known standard current from large Daniell cells is +sent through this coil during a certain time, and thus the magnet is +brought back to its original degree of saturation. M. Ducretet also +mentions the use of a soft iron bar instead of a steel magnet, in which +case the current from the Daniell cells must be kept on during the time +an observation is taken.) But such a system would appear to be too +complicated for ready use. Moreover, some sort of indicator would be +required by which we could make sure that the exciting current has the +normal strength. + +[Illustration: FIG 4.] + +The plan we adopt is to excite the electro magnet by the whole or a part +of the current which is to be measured. Since this current varies, the +power exciting the core of the electro magnet must also vary; and since +we require the core to have as nearly as possible a permanent magnetic +force, we are brought face to face with the question, whether an electro +magnet can be constructed that has a constant moment under varying +exciting currents. This question has been answered by the well known +experiments of Jacobi, Dub, Mueller, Weber, and others. To get an +absolutely constant magnetic moment, is not possible, but between +certain limits we can get a very near approximation to constancy. + +[Illustration] + +The relation between exciting power and magnetic moment is very +complicated, depending not only on the dimensions and shape of the core +and the manner of winding, but also on the chemical constitution of the +iron of the core. It is not possible, or at least it has hitherto not +been found possible, to embody all these various elements into an exact +mathematical formula, which would give the magnetic moment as a function +of the exciting current; but the above mentioned experiments have shown +that within certain limits, and in the neighborhood of the point of +saturation, the relation between the two is that of an arc to its +geometrical tangent. It will be seen that for large angles the arc +increases much slower than the tangent; that is, for strongly excited +cores, a very large increase of the exciting current will produce only +a slight increase of magnetic moment. If Mueller's formula were correct +for all currents, absolute saturation could only be reached with an +infinite current. Whether this be the case or not, it is certain that +the greater the exciting current the less will a variation in it affect +the magnetic moment of the core. To imitate as nearly as possible +permanent steel magnets, it is therefore necessary to use electro +magnets, the cores of which are easily saturated. The core should be +thin and long and of the horseshoe type; the amount of wire wound round +it should be large in comparison with the size of the core. + +[Illustration] + +Here is a magnet partly wound which was used in one of our earliest +experiments, but which was a failure on account of having far too much +mass in the core in comparison with the amount of copper wire wound +round it. Since then we have greatly diminished the iron and increased +the copper. The cores of the instruments on the table are composed of +two or three No. 18 b.w.g. charcoal iron wires, and are wound with one +layer of 0'120 inch wire in the case of the current indicators, and +eighteen layers of 0.0139 inch wire in the case of the potential +indicator. If from the diagram, Fig. 1, we plot a curve the abscissae of +which represent exciting current, and the ordinates magnetic moment of +the soft iron core, we find that a considerable portion of the curve +is almost a straight and only slightly inclined line. If it, were a +horizontal straight line the core would be absolutely saturated, but +such as it is, it answers the purpose sufficiently well, for with a +variation of exciting current from 10 to 100 amperes the magnetic moment +varies but slightly. If a small soft iron or magnetic steel needle, _n +s_, be suspended between the poles, S N, of an electro magnet of such +proportions as described above, and the current, after exciting the +electro magnet, _e e_, be lead round the coils, DD, it will be found +that for all currents between 10 and 100 amperes the needle, _n +s_, shows a definite deflection for each current. Here we have a +galvanometer with permanent calibration. In this case the deflection of +the needle will not strictly follow the law of tangents, because the +directing power of the electro magnet is not absolutely constant; but +whatever the exact ratio between deflection and current may be, it must +always remain the same, and to each angle of deflection corresponds one +definite strength of current. + +[Illustration] + +The force with which the electro magnet tends to keep the needle in its +zero position, that is, in line with the poles, S N, is due partly to +the magnetism of the core, which is nearly constant, and partly to the +magnetic influence of the coils, _ee_, themselves, which is, of course, +simply proportional to the current. The total magnetic force acting on +the needle is, therefore, represented by the sum of these two forces, +and consequently not nearly so constant as might be desired in order to +get a good imitation of a tangent galvanometer with a permanent magnet. +In the diagram, Fig. 2, the curve, O A B, represents the magnetic moment +of the iron core, the straight line, ODE, that of the exciting coils per +se, and the dotted line, O F M, the sum of the two, obtained by adding +for every current, O C, the respective ordinates, CD and C A. + + CF = CD + CA + +The rise of this curve shows that the force which tends to bring the +needle back to its zero position increases with the current, though at a +slower ratio than the deflecting force of the current. It follows from +this that for large currents the increment in the angle of deflection is +comparatively small, and the divisions on the scale whereon the current +is to be read off would come too near together to allow accurate +readings to be taken. In other words, the range of accurate reading in +an instrument so constructed would only be limited. But it is very easy +to eliminate the magnetic effect of the coils of the electro magnet on +the needle, by introducing an opposite magnetic effect, so that only +that part of the force remains which belongs to the soft iron core +proper. One way of doing this is by surrounding the needle with a coil, +the plane of which is at right angles to the line, S N, and coupling +this coil in series with the deflecting coil, D D. If the proportions +of this transverse coil and the direction of the current through it +be properly chosen, its magnetic effect can be made to exactly +counterbalance that of the exciting coils, _e e_, without perceptibly +weakening the magnetism of the iron core. But instead of employing two +coils, one parallel and the other transversely to the zero position of +the needle, we can obtain the same result in a more simple manner with +one coil only, if this be placed at such an angle that its magnetic +effect can be substituted for the combined effects of the two coils. In +other words, we set the deflecting coil, D D, at a certain angle to the +zero position of the needle. + +A similar arrangement, though not precisely for the same purpose, has +already been suggested and tried by Messrs. Deprez, Carpentier, Ayrton, +and Perry, in galvanometers with permanent steel magnets. If the coil, +D D, be so placed, the deflecting force which now acts obliquely can be +considered as the resultant of two forces, one acting at right angles to +the line, S N, as in an ordinary galvanometer, and the other parallel to +this line, but in a sense opposed to the action of the electro magnet +and its exciting coils. If the angle of obliquity be so chosen that this +latter component exactly equals the magnetic effect of the exciting +coils _per se_, an equality which holds good for all currents, then we +shall have an almost perfect imitation of a tangent galvanometer with +permanent magnets. But we can go a step further than this; we can +overbalance the exciting coils by setting the deflecting coil at a +greater angle than necessary for the mere elimination of the former, and +thus attain that an increase of current results in a slight weakening of +the field in which the needle swings, thus allowing the increment of the +angle of deflection to be comparatively large even for large currents. +In this way it is possible to obtain a more evenly divided scale than +in the case when the deflection follows the law of tangents, as in an +ordinary tangent galvanometer. This principle of overbalancing the +exciting coils is shown on diagram, Fig. 2. The straight line, O G, +represents the magnetic effect on the needle of that component of the +deflecting force which is parallel, but in sense opposed to S N; +as mentioned above, the magnetic effect of the exciting coils is +represented by the straight line, O E. The combined effect of these two +forces on the needle is represented by the line, O K, the ordinates +of which must be deducted from those of the curve, O A B, in order to +obtain the total directing force due to each current. This is shown by +the curve, O P Q, shown in a thick full line. This curve shows how +the directing force or strength of field in which the needle swings +decreases with an increasing current. That this does actually take place +can easily be proved by experiment. + +Fig. 4 shows two curves; the one drawn in a full line is obtained +by plotting the deflection in degrees of the needle of a potential +indicator as abscissae, and the corresponding electromotive forces +measured simultaneously on a standard instrument as ordinates; the +dotted line shows what this curve would be with an ordinary tangent +galvanometer. + +The needle of the potential indicator is mounted at the lower end of +a steel axle, to the upper end of which is fastened a light aluminum +pointer, whereby the deflection of the needle can be read off on a scale +divided directly into volts. The scale is placed within a circular dial +plate with glass cover, giving sufficient room for the pointer to swing +all round, and the needle is placed within a central tube fitting it +closely, which acts as a damper and so makes the instrument almost +dead beat. Tube and dial are in one casting. The electro magnet is of +horseshoe form fastened to a central tubular stand, which also serves +to support the two deflecting coils, one on either side of it. The tube +within which the magnetic needle swings is inserted into the stand, +which is bored out to the external diameter of the tube. The electro +magnet and deflecting coils are wound with from 50 to 100 ohms of fine +insulated copper wire, and an additional resistance coil of from 450 +to 900 ohms of German silver is added, which can, however, be short +circuited by depressing a key when the instrument has to be used for +reading low electromotive forces. In this case the indication of the +pointer must be divided by ten. If a current be sent through the +instrument the wrong way, the needle turns through an angle of 180°, and +thus brings the pointer to the side of the dial opposite to where the +scale is. In this position no reading can be taken, and to facilitate +the sending of the current in the right direction a commutator is added, +and the same is so coupled up that when the pointer stands over the +scale the handle on the commutator points to the positive terminal +screw. There is a limit of electromotive force below which the indicator +fails to give reliable readings. For instance, an instrument wound with +100 ohms of copper wire and 900 ohms of German silver can be used for +electromotive forces varying between 300 and 3 volts, but would not be +reliable for measuring less than 3 volts. + +For very exact measurements the instrument should be placed north and +south, in the same position in which it was calibrated. Two different +patterns of current indicators are on the table; one with double needles +suspended on a point in the way compass magnets are suspended, the other +with one lozenge shaped needle mounted on an axle and pivoted on jewels, +in every way similar to the needle of the potential indicator first +described. + +For measurements of currents from 10 amperes upward, there is no need +to employ a complete coil as the deflecting agent; one half-coil or one +strip passing close under the needle gives sufficient deflecting force, +and thus the construction of the instrument is rendered extremely +simple. The current, after entering at one of the flat electrodes, +splits in two parts, each part passing round the winding of an electro +magnet of horseshoe form, the similar poles of both magnets pointing +toward each other and toward the needle. After traversing the winding, +the current unites again, and passes through a metal strip close under +the needle, and finally out of the instrument by the other electrode, +which lies close under that at which the current entered, but is +insulated from it by a sheet of fiber. The metal strip is set at an +angle, to balance or overbalance, as may be preferred, the magnetic +influence of the exciting coils. The effect of this overbalancing is +shown in Fig. 5, where the full curve represents the current as a +function of the deflection--obtained by comparison with a standard +instrument--and the dotted curve shows what that relation between +deflection and current would be if the law of tangents held good for +these instruments. It will be seen that, about the middle of the scale, +the dotted line coincides nearly with the full line, while at the +extreme end of the scale the dotted line is higher. From this follows, +that if we compare our indicator from which this curve was taken with +any form of tangent instrument showing an equal angle of deflection at +the medium reading, it will be seen that the needle of our indicator +will be deflected to a greater angle at high readings than that of the +tangent galvanometer. Consequently, the divisions on the scale will +be widest apart in our instruments, which greatly facilitates high +readings. + + * * * * * + + + + +SECONDARY BATTERIES. + + +The Consolidated Electric Light Company has now completed the secondary +battery which has for some time engaged the attention of its officers, +and their regular manufacture and use for electric lighting stations +have been fairly entered upon. Among other places to which the batteries +have been sent and put into work is Colchester, where the company +has for some time had an installation at work, chiefly employing +incandescent lamps. The battery consists of lead electrodes, anode and +cathode being of the same character. They are constructed of narrow +ribbons of lead, each element being made from long lengths of the ribbon +about or nearly 0.20 in. width, rolled together into a flat cake like +rolls of narrow webbing, as illustrated by the annexed diagram, Fig. +1, the greater part of the ribbon being very thin and flat; but +intermediate thicker ribbons are also employed, as in Fig. 2, this +thicker ribbon being corrugated as shown, and affording passage room +for the circulation of the electrolyte. From four to eight coils of the +plain ribbons are between every pair of corrugated ribbons. They are +wound up together tightly, and pressed into the nearly rectangular form +shown. The bar for suspending the coil plates so made in the cells is +soldered to the coil. The object of this construction is of course to +obtain large lead surface, and of course a much larger surface is so +obtained than could be practically obtained from plain lead plates in +the same compass. A battery thus made may be seen at the offices of the +company, 110 Cannon Street. + +[Illustration: FIG. 1. FIG. 2.] + +A very ingenious device for cutting the battery out of circuit when +charged as much as is thought desirable is used by the company. In a +cell is an element which has a determined lower capacity than those in +the rest of the battery. Over this element is placed a gas-tight chamber +in which is a diaphgram, this diaphragm being of very flexible material +placed in the cover of the box of cells. When charging has proceeded as +long as is desirable, or proceeds too fast, hydrogen is evolved, and +this collecting in the chamber referred to acts upon the diaphragm, and +by means of a rod connected thereto, switches the current, which is +supplied to an electro-magnet and by which circuit is made through the +medium of mercury contacts. The object, of this is to save the +battery from destruction by over-charging or charging by too large a +current.--_The Engineer_. + + * * * * * + + + + +ACETYLENE FROM IODOFORM. + + +P. CAZENEUVE publishes in the _Comptes Rendus_ a new method for the +preparation of acetylene, which consists in mixing iodoform intimately +with moist and finely divided silver. An abundant evolution of acetylene +takes place without heating. The reaction is represented by the +following formula: 2CHI_{3} + 6Ag = C_{2}H_{2} + 6 AgI. The +decomposition of the iodoform is hastened if the silver is mixed with +finely divided copper, such as can be obtained by precipitating it from +its sulphate by means of zinc. + +Cazeneuve also observed that most metals which have any affinity for +iodine will decompose iodoform in the presence of water, forming +acetylene and an iodide of the metal. By the use of zinc he obtained a +liquid having a pleasant ethereal odor, and a gas mixture that contained +besides acetylene an iodine compound which burned with a purple-edged, +fawn-colored flame. + + * * * * * + + + + +WHEN DOES AN ELECTRICAL SHOCK BECOME FATAL? + + +In this age of electricity and electric wires carrying currents of +various intensity, the question of danger arising from contact with them +has caused considerable discussion. An examination into the facts as +they exist may therefore enlighten some who are at present in the dark. + +To begin with, we often hear the question asked--why is it that certain +wires carrying very large currents give very little shock, whereas +others, with very small currents, may prove fatal to those coming in +contact with them? The answer to this is--that the shock a person +experiences does not depend upon the current _flowing in the wires_, but +upon the current _diverted from them_ and _flowing through the body_. + +The muscular contraction due to a galvanic current, which was first +observed in the frog, gives a good illustration of the fact that it +requires only a very minute current to flow through the muscles in order +to contract them. Thus the simple contact of pieces of zinc and copper +with the nerves generated current sufficient to excite the muscles--a +current which would require a delicate galvanometer for its detection. +What is true of the muscles of the frog holds good also for the human +muscles; they too are very susceptible to the passage of a current. + +In order to determine the current which proves fatal we need only to +apply the formula which expresses Ohm's law, viz., C=E/R, or the current +(ampere) equals the electromotive force (volt) divided by the resistance +(ohm). + +According to the committee of Parliament investigation, the +electromotive force dangerous to life is about 300 volts; this then is +the quantity, E, in the formula. There remains now only to determine the +resistance in ohms which the body offers to the passage of the current. +In order to obtain this, a series of measurements under different +conditions were made. On account of the nature of the experiment a high +resistance Thomson reflecting galvanometer was used, with the following +results. + +When the hands had been wiped perfectly dry, the resistance of the body +was about 30,000 ohms; with the hands perspiring ordinarily it fell to +10,000 ohms; whereas when they were dripping wet it was as low as 7,000 +ohms. Our readers can judge this resistance best when we state that the +Atlantic cable offers a resistance of 8,000 ohms. + +Taking an ordinary condition of the body, with the hands perspiring as +usual, we would have the resistance equal to 10,000 ohms. Applying the +two known quantities in the formula, we get: + + C = (300 / 10,000) - (1 / 33.333+) + +This means, therefore, that when the electromotive force or potential is +great enough to send a current of 1/33 ampere through the body, fatal +results will ensue. This current is so minute that it would deposit only +about 6 _grains_ of copper in _one hour_, a grain being 1/7,000 of a +pound. + +Let us now compare these figures with some actual cases, taking as +an example a system of incandescent lighting. In these systems the +difference of potential between any two points of the circuit outside of +the lamps does not exceed 150 volts. Taking this figure, therefore, it +will be seen that under no circumstances can the shock received from +touching these wires become dangerous--not even by touching the +terminals of the dynamo itself; because in neither case can a current be +driven through the body, sufficient to cause an excessive contraction of +the muscles. + +In a system of arc lighting, however, we have to deal with entirely +different conditions; for, while in the incandescent system the adding +of a lamp, which diminishes the resistance, requires no increase of +electromotive force, the contrary is the case in the arc light system. +Here every additional lamp added to the circuit means an increase in +resistance, and consequent increase in electromotive force or potential. +Taking for example a well known system of arc lighting, we find that the +lamps require individually an electromotive force of 40 volts with a +current of 10 amperes. In other words, the difference in potential at +the two terminals of every such lamp is 40 volts. Consequently, if the +circuit were touched in two places, including between them only one +lamp, no injurious effects would ensue. If we touch the circuit so as +to include two lamps between us, the effect would be greater, since the +potential between those two points is 2 x 40 volts. We might continue +in this manner touching the circuit until we had included about 7 or +8 lamps, when the shock would become fatal, since the point would be +reached at which the difference of potential is great enough to send a +dangerous current through the body. + +Up to this point we have assumed that, while touching two points in the +wire, the rest of the circuit is perfectly insulated, so that no current +can leak, in other words, that the circuit is nowhere "grounded." If +this is not the case we may, under suitable conditions, receive a +shock by touching only _one_ point of the wire. This becomes clear +by considering the current to leak from another spot of different +potential, to pass through the ground and into the body; thus, on +touching the wire the body virtually makes a connection between the +two points of the circuit. In clear dry weather such leaks are +insignificant; but in damp and rainy weather, and with poor insulation, +they may rise to such a point at which it would be dangerous to touch +the circuit even with one hand, the leaks being sometimes so great as +to cause the lamps to burn in a fitful, desultory manner, and to go out +entirely. + +There is still another factor which enters into the discussion of the +danger of electric light wires. This must be looked for in the fact that +the physiological effects are greatest at the moment of the opening or +the closing of the circuit; or in a closed circuit they are the more +marked when the flow of current stops and starts, or diminishes and +increases. In dynamo electric machines the current is not absolutely +continuous or uniform, since the coils on the armature being separated a +distance cause a slight break or diminution of the current between each. +This break is so short that it does not interfere with the practical +work for lighting; in some constructions, nevertheless, the distances +apart is so great that, while not interfering with light, its effects +upon the muscles are greatly increased over those of other constructions +which give a more uniform current. + +All these statements might lead to the conclusion that arc light wires +are dangerous under any circumstances; but this is not the case. The +first and only requisite is, that they be perfectly insulated. When thus +protected accidents from them are impossible, and all mishaps that have +occurred through them can be traced directly to the lack of insulation. +Nevertheless, we would warn our readers against experimenting upon arc +wires by actual trial, because unforeseen conditions might lead to +disagreeable results. + + * * * * * + + + + +ROBERT CAUER'S STATUE OF LORELEI. + + +The statue of Lorelei, the mythical siren of the Rhine, represented in +the annexed cut, which is taken from the _Illustrirte Zeitung_, was +modeled by Robert Cauer, of Kreuglach on the Rhine. He was born at +Dresden in 1831, and is the son of the well-known sculptor Emil Cauer, +and a brother of the sculptor Karl Cauer. + +[Illustration: LORELEI STATUE BY ROBERT CAUER.] + + * * * * * + + + + +REDUCING AND ENLARGING PLASTER CASTS. + + +Ordinary casts taken in plaster vary somewhat, owing to the shrinkage of +the plaster; but it has hitherto not been possible to regulate this +so as to produce any desired change and yet preserve the proportions. +Hoeger, of Gmuend, has, however, recently devised an ingenious method +for making copies in any material, either reduced or enlarged, without +distortion. + +The original is first surrounded with a case or frame of sheet metal or +other suitable material, and a negative cast is taken with some elastic +material, if there are undercuts; the inventor uses agar-agar. The usual +negative or mould having been obtained as usual, he prepares a gelatine +mass resembling the hektograph mass, by soaking the gelatine first, then +melting it and adding enough of any inorganic powdered substance to give +it some stability. This is poured into the mould, which is previously +moistened with glycerine to prevent adhesion. When cold, the gelatine +cast is taken from the mould, and is, of course, the same size as the +original. If the copy is to be reduced, this gelatine cast is put in +strong alcohol and left entirely covered with it. It then begins to +shrink and contract with the greatest uniformity. When the desired +reduction has taken place, the cast is removed from its bath. From +this reduced copy a cast is taken as usual. As there is a limit to the +shrinkage of the gelatine cast, when a considerable reduction is desired +the operation is repeated by making a plaster mould from the reduced +copy, and from this a second gelatine cast is taken and likewise +immersed in alcohol and shrunk. It is claimed that even when repeated +there is no sacrifice of the sharpness of the original. + +When the copy is to be enlarged instead of reduced, the gelatine cast is +put in a cold water bath, instead of alcohol. After it has swollen as +much as it will, the plaster mould is made as before. For enlarging, +the mould could also be made of some slightly soluble mass, and then by +filling it with water the cavity would grow larger, but it would not +give so sharp a copy. + + * * * * * + + + + +STRIPPING THE FILM FROM GELATINE NEGATIVES. + + +We have frequent inquiries as to the best means of removing a +gelatino-bromide negative from its glass support so that it can be used +either as a direct or reversed negative, and it does not appear to be +very generally known that about two years ago Mr. Plener described a +method which answers well under all circumstances, whether a substratum +has been used or not. + +If a negative is immersed in extremely dilute hydrofluoric acid +contained in an ebonite dish, say half a teaspoonful to half a pint of +water, the film very soon becomes loosened, and floats off the glass, +this circumstance being due to the solvent action which the acid +exercises upon the surface of the plate as soon as it has penetrated the +film. If the floating film be now caught upon a plate which has been +slightly waxed, and it is allowed to dry on this plate, it will become +quite flat and free from wrinkles. To wax the plate, it should be held +before the fire until it is moderately hot, after which it is rubbed +over with a lump of wax, and the excess is polished off with a piece +of flannel. When the film is dry, it will leave the waxed glass +immediately, if one corner is lifted by means of a penknife. The film +will become somewhat enlarged during the above-described operation; but, +by taking suitable precautions, this enlargement may be avoided. It is +also convenient to prepare the hydrofluoric acid extemporaneously by the +action of sulphuric acid on fluoride of sodium; and, in many cases, it +is advisable to thicken up the film by an additional layer of gelatine. + +The following directions embody these points. The negative, which must +be unvarnished, is leveled, and covered with a layer of warm gelatine +solution (one in eight) about as thick as a sixpence. This done, and +the gelatine set, the plate is immersed in alcohol for a few minutes +in order to remove the greater part of the water from the gelatinous +stratum. The next step is to allow the plate to remain for five or six +minutes in a cold mixture of one part of sulphuric acid with twelve +parts of water, and in the mean time two parts of sodium fluoride are +dissolved in one hundred parts of water, an ebonite tray being used. A +volume of the dilute sulphuric acid equal to about one-fourth of the +fluoride solution is next added from the first dish, and the plate +is then transferred to the second dish, when the film soon becomes +liberated. When this is the case, it is placed once more in the dilute +sulphuric acid. After a few seconds it is rinsed in water, and laid on a +sheet of waxed glass, complete contact being established by means of a +squeegee, and the edges are clamped down by means of strips of wood held +in position by American clips or string. All excess of sulphuric acid +may now be removed by soaking the plate in methylated alcohol, after +which it is dried. It is as well to add a few drops of ammonia to the +last quantity of alcohol used. + +The plate bearing the film negative is now placed in a warm locality, +under which circumstances a few hours will suffice for the complete +drying of the pellicular negative, after which it may be detached +with the greatest ease by lifting the edges with the point of a +penknife.--_Photo. News_. + + * * * * * + + + + +NEW ANALOGY BETWEEN SOLIDS, LIQUIDS, AND GASES, + +By W. SPRING. + + +The author asks in the first place, What is the cause of the different +specific gravities of one and the same metal according as it has been +cast, rolled, drawn into wire, or hammered? Does the difference observed +prove a real condensation of the matter under the action of pressure, or +is it merely due to the expulsion by pressure of gases which have been +occluded when the ingot was cast? According to well-known researches, +metals such as platinum, gold, silver, and copper, which have +been proved to occlude gases on fusion, and to let them escape, +_incompletely_, on solidification, are precisely those which are +most increased in their specific gravity by pressure. The author has +submitted to pressures of about 20,000 atmospheres metals which possess +this property, either not at all, or to a very trifling extent, and he +finds that though a first pressure produces a slight permanent increase +of density, its repetition makes little difference. Their density is +found to have reached a maximum. Hence the density of solids, like that +of liquids, is only really modified by temperature. Pressure effects +no permanent condensation of solid bodies, except they are capable of +assuming an allotropic condition of greater density. The author's former +researches tend to show that solid matter, in suitable conditions of +temperature, takes the state corresponding to the volume which it is +compelled to occupy. Hence there is an analogy between the allotropic +states of certain solids and the different states of aggregation of +matter. Possibly the different forms of matter may be due to a single +cause--polymerization. The limit of elasticity of a solid body is the +critical moment when the matter begins to flow under the action of the +pressure to which it is submitted, just as, e.g., ice at or below 0° may +be liquefied by strong pressure. A brittle body is simply one which does +not possess the property of flowing under the action of pressure. + + * * * * * + + + + +HYDROGEN AMALGAM. + + +Hydrogen, although a gas, is recognized by chemists as a metal, and when +combined with any solid metal--as in the case known to electricians as +the polarization of a negative element,--the compound may correctly be +termed an alloy; while any compound of hydrogen with the fluid metal +mercury may with equal correctness be termed an amalgam of hydrogen, or +"hydrogen amalgam." The efforts of many chemists and mining engineers +have for many years been devoted to a search for some effective and +economical means for preventing the "sickening" of mercury and its +consequent "flouring" and loss. Some sixteen or more years ago, +Professor Crookes, F.R.S., discovered and, after a series of +experiments, patented the use of an amalgam of the metal sodium for this +purpose. He made the amalgam in a concentrated form, and it was added +in various proportions to the mercury used for gold amalgamation. Water +becoming present, it will readily be understood that the sodium, in +being converted into the hydrate (KHO) of that metal, caused a rapid +evolution of hydrogen. The hydrogen thus evolved was the excess over a +certain proportion which enters into combination with the mercury. While +the mercury retained the charge of hydrogen, the "quickness" of the +fluid metal was preserved; but upon the loss of the hydrogen the +"quickness" ceased, and the mercury was acted upon by the injurious +components contained in the ore. + +Since the introduction of the sodium amalgam, many attempts have been +made, more especially in America, to overcome the tendency of mercury to +"sicken" and lose its "quickness." The greater number of these efforts +have been made by the use of electricity as the active agent in +attaining this end; but such efforts have been generally of a crude and +unscientific character. Latterly Mr. Barker, of the Electro-amalgamator +Company, Limited, has introduced a system--already detailed in these +pages--by which the mercury is "quickened." In his method the running +water passing over the tables, or other apparatus of a similar +character, is used as the electrolyte. In this arrangement, the mercury +being the cathode, plates or wires of copper constituting anodes are +brought into contact with the water passing over the mercury in each +"riffle." Both the cathode and the anodes are, of course, maintained in +contact with the poles of a suitable source of electrical supply. The +current then passes from the copper anode through the running water +to the mercury cathode, and so on to the negative pole of the +electro-motor. As a consequence of this arrangement, hydrogen is evolved +from the water, and has the effect of reducing any oxide or other +detrimental compound of the metal; in other words, it "quickens" and +prevents "sickening" of the fluid metal, and consequent "flouring" and +loss. While the hydrogen is evolved at the cathode, oxygen enters into +combination with the copper constituting the anodes. This to some extent +impairs the conductivity of the circuit. + +The latest process, however, is that of Mr. Bernard C. Molloy, M.P., +which we have already characterized as highly scientific and effective, +the production of a suitable amalgam being obtained under the most +economical and simple conditions. This process has the advantage of +producing not only a hydrogen amalgam, but also at will an amalgam of +hydrogen combined with any metal electro-positive to this latter. Thus +hydrogen potassium or hydrogen sodium can be obtained, as will be seen +by the following description. + +Mr. Molloy's effort appears to have been, in the first place, directed +to a system which could be adapted to any existing apparatus, and in +certain cases where water was scarce, to avoid altogether the use of +that, in some districts, rare commodity. For the purpose of explanation +we select an ordinary amalgamating table fitted with mercury riffles. +The surface of the table is in no way interfered with or disturbed. The +bed of the riffle, however, is constructed of some porous material, such +as leather, non-resinous wood, or cement, which serves as the diaphragm +upon which the mercury rests, and separates the fluid metal from the +electrolyte beneath. Running the full length of the table is a thin +layer of sand, supported and pressing against the diaphragm, and lying +in this sand is the anode, formed preferably of lead. A peroxide of +that metal is formed by the action of the currents, and may be readily +reduced for use over and over again after working for from one to three +months. The peroxide of lead, as is well known, is a conductor of +electricity, and this fact constitutes an important advantage in the +working of the process. The thin layer of sand is saturated with an +electrolyte, such as dilute sulphuric acid (H_{2}SO_{4} + 20H_{2}O) +to give a simple hydrogen amalgam; (Na_{2}SO_{4} + xH_{2}O) to give a +hydrogen sodium amalgam; or (K_{2}SO_{4} + xH_{2}O) to give a hydrogen +potassium amalgam. Numerous other electrolytes constituted by acids, +alkalies, and salts can be used to form an amalgam permanently +maintained in a condition of "quickness" and freed from all liability +to "sicken," whatever the components of the ore may be. The mercury +is connected with the negative pole of the voltaic battery or other +electro-motor, and the lead made with the positive pole of the same +source. When the current passes there is formed according to the nature +of the electrolyte, a hydrogen amalgam, or an amalgam of hydrogen with a +metal electro-positive to hydrogen. The electrolyte, which, it will be +understood, is distinct and apart from the body of water passing over +the table, will last almost indefinitely, there being no consumption of +any of its constituents, excepting hydrogen and oxygen from the water +of solution. The quantity of acid or saline material contained in the +electrolyte is so very small that there can be no difficulty in finding +a supply in any district. The question of the supply of electricity is +one which in many mining districts involves considerations of practical +importance, since a large supply would necessitate water or steam power. +It has been found that two cells having an electromotive force of about +two volts each will in this process suffice; if preferred, however, +a very small dynamo machine can be used. In connection with the +electro-motive force it is requisite to use, it may be observed that an +amalgam of sodium containing only a small quantity of this metal would, +when constituting a positive element in conjunction with a lead negative +and on an aqueous electrolyte, give an opposing electro-motive force of +less than three volts. Such an amalgam could therefore be obtained under +an electro-motive force of about four volts. The electrical resistance +in the circuit constituted by the apparatus being very small, no +electrical power is wasted. When water constitutes the electrolyte, as +in Barker's system, then the electro-motive force required to obtain a +given current would be very much greater than that above specified. +The conditions assured under this process appear to be all that can +be required, while the amalgams obtained are those most calculated to +preserve the "quickness" and prevent the "sickening" of the mercury. + +Mr. Molloy has designed a special form of amalgamating machine to be +used in conjunction with the above process, and with or without the aid +of water. By the employment of this machine, each particle of the ore +is slowly rolled in the quickened mercury for from fifteen to thirty or +more seconds. + +When the extent of the gold and silver mining industries is considered, +and when it is borne in mind that a considerable percentage of the +precious metal present in the ore is, in the ordinary process of +extraction, lost through defective amalgamation--due to insufficient +contact with the mercury or to a total absence of contact, as in the +case of float gold--it is obvious that the introduction of any system +obviating such loss is a matter of very great importance to those who +are interested in the above mentioned industries. We expect shortly to +hear of the practical introduction on a large scale of Mr. Molloy's +process, and we look forward with interest to the results which may be +obtained from it.--_The Engineer_. + + * * * * * + + + + +TREATMENT OF ORES BY ELECTROLYSIS. + +By M. KILIANI. + + +The author lays down general principles for electrolytic metallurgy. +Ores must be distinguished as good and bad conductors; the former +may serve directly as anodes, and are easily oxidized by the +electro-negative radicals formed at their contact, and dissolve readily +in the electrolyte. The bad conductors have to be placed in contact +with a conducting anode, formed of an inoxidizable substance, such as +platinum, manganese peroxide, or coke. In laboratory experiments a good +conducting ore is electrolyzed by suspension from a platinum wire in +connection with the source of electricity, and is then immersed in the +bath. On an industrial scale the ore, coarsely broken up, is placed in +one of the compartments of a trough divided by a diaphragm. + +On the fragments of the ore which extend up outside of the electrolytic +bath is laid a plate of copper connected with the positive wire. Care +must be taken that this plate does not plunge into the bath, otherwise +the current would not traverse the ore at all. The cathode is preferably +formed of the same metal which is to be obtained. The bath should +not contain organic acids. In practice the common mineral acids are +employed, or their salts, selecting by preference a salt of the metal +which is to be isolated. It is convenient to pass the current through +the greatest possible number of small decomposition troughs, taking care +that the resistance in each is not too great. With a current of one and +the same intensity we obtain in n troughs n times as much metal as in a +single one. To keep down the resistance of the circuit we employ poles +of a large surface, i.e., plenty of ore and baths which are as good +conductors as possible. + +The state in which the metal is deposited at the negative pole depends +on the secondary actions undergone by the electrolyte, and especially of +the escape of gas. This is a function of the _density_, of the current, +i.e., the proportion of its intensity to the surface of the cathode. If +the density is too great there is an escape of hydrogen, and the metal +is deposited in a spongy condition. If the density of the current falls +below a certain minimum, an oxide is deposited in place of metal. The +electrolytic treatment of ores often renders it possible to separate +the different metals which may be present. These are deposited in +succession, and are sharply separated if the electromotive power is not +too great. + +1. _Zinc_.--The zinciferous compounds--calamine, blende, and zinc +ash--are all poor conductors. They are first dissolved, and the salts +obtained are electrolyzed, employing anodes of coke. Blende should be +roasted before it is dissolved. The electrolytic bath should be as +concentrated as possible to avoid sponginess of the metal and an escape +of hydrogen. In a saturated solution the formation of hydrogen decreases +as the density of the current augments. + +2. _Lead_.--Galena is a good conductor, and may be directly +electrolyzed. The best bath is a solution of lead nitrate. The +arborescent crystallizations extend rapidly, and must be broken from +time to time to prevent the formation of a metallic connection between +the anode and the cathode. The sulphur of the galena falls to the bottom +of the bath, and may be separated from the gangue by solution in carbon +disulphide. + +3. _Copper_.--Native copper sulphide, though a good conductor, cannot +be directly electrolyzed en account of the presence of iron sulphide, +whence iron would be deposited along with the copper. The copper pyrites +are roasted, dissolved in dilute sulphuric acid, and the liquid thus +obtained is submitted to electrolysis. + + * * * * * + + + + +A PEOPLE WITHOUT CONSUMPTION, AND SOME ACCOUNT OF THEIR COUNTRY--THE +CUMBERLAND TABLELAND. + +By E. M. WIGHT, M.D., Chattanooga, Tenn., Late Professor of Diseases +of the Chest and State Medicine, Medical Department University of +Tennessee; Late Member of the Tennessee State Board of Health, and +ex-President of the Tennessee State Medical Society. + + +During the ten years that I have practiced medicine in the neighborhood +of the Cumberland Tablelands, I have often heard it said that the +people on the mountains never had consumption. Occasionally a traveling +newspaper correspondent from the North found his way down through the +Cumberlands, and wrote back filled with admiration for their grandeur, +their climate, their healthfulness, and almost invariably stated that +consumption was never known upon these mountains, excepting brought +there by some person foreign to the soil, who, if he came soon enough, +usually recovered. Similar information came to me in such a variety of +ways and number of instances, that I determined some four years ago, +when the attempt to get a State Board of Health organized was first +discussed by a few medical men of our State, that I would make an +investigation of this matter. These observations have extended over that +whole time, and have been made with great care and as much accuracy +as possible, and to my own astonishment and delight, I have become +convinced that pulmonary consumption does not exist among the people +native and resident to the Tablelands of the Cumberland Mountains. + +In the performance of the work which has enabled me to arrive at this +conclusion, I have had the generous assistance of more than twenty +physicians, who have been many years in practice in the vicinity of +these mountains. Their knowledge of the diseases which had occurred +there extended over a, period of more than forty years. Some of these +physicians have reported the knowledge of the occurrence of deaths from +consumption on the Tablelands, but when carefully inquired into they +have invariably found that the person dying was not a native of the +mountains, but, a sojourner in search of health. In answer to the +question: "How many cases of pulmonary consumption have you known to +occur on Walden's Ridge, among the people native to the mountains?" +eleven physicians say, "Not one." All of these have been engaged in +practice there more than three years, four of them more than ten years, +one of them more than twenty, and one of them more than forty years. All +the physicians of whom inquiries have been made are now residents, or +have been, of the valleys contiguous to Walden's Ridge, and know the +mountain people well. Four other physicians in answer to the same +question say, that they have known from one to four cases, numbering +eleven in all, but had not ascertained whether five of them were born +and raised on the mountains or not. The names and place of death of all +these cases were given, and I have traced their history and found that +but three of them were "natives," or had lived there more than five +years, and that one of these was 57 years of age when she died, and had +suffered from cancer for three years before her death. The two others +died within six months after returning home from long service in the +army, where both contracted their disease. + +All these investigations have been made with more particular reference +to that part of the Cumberlands known as Walden's Ridge than to the +mountains as a whole. This ridge is of equal elevation and of very +similar character to the main Cumberland range in the southern part of +Tennessee, northwest Georgia, and northwest Alabama, and what is true of +this particular part of the great Cumberland table is, in the main, true +of the remainder. + +Sequatchee Valley lies between Walden's Ridge and what is commonly known +in that neighborhood as the Cumberland Mountains, and separates it from +the main range for a distance of about one hundred miles, from the +Tennessee River below Chattanooga to Grassy Cove, well up toward the +center line of the State. Grassy Cove is a small basin valley, which +was described to me there as a "sag in the mountains," just above the +Sequatchee Valley proper. It is here that the Sequatchee River rises, +and flowing under the belt of hills which unites the ridge and the main +range, for two miles or more, rises again at the head of Sequatchee +Valley. Above Grassy Cove the mountains unite and hold their union +firmly on their way north as far as our State reaches. + +Topographically considered as a whole, the Cumberland range has its +southern terminus in Alabama, and its northern in Pennsylvania. It +is almost wholly composed of coal-bearing rocks, resting on Devonian +strata, which are visible in many places in the valleys. + +But a small portion of the Cumberland lies above a plane of 2,000 feet. +Walden's Ridge and Lookout Mountain vary in height from 2,000 to 2,500 +feet. + +North of Grassy Cove, after the ridges are united, the variation from +2,000 feet is but little throughout the remainder of the State, and +the general character of the table changes but little. The great and +important difference is in the climate, the winters being much more +severe in these mountains in the northern part of the State than in the +southern, and the summers much more liable to sudden changes of weather. +Scott, Fentress, and Morgan counties comprise this portion of the table, +and these have not been included in my examination, excepting as to +general features. + +In all our southern country, and I may say in our whole country, there +is no other large extent of elevated territory which offers mankind +a pleasant living place, a comfortable climate--none too cold or too +hot--and productive lands. We have east of the upper waters of the great +Tennessee River, in our State, and in North Carolina and Georgia, the +great Blue Ridge range of mountains, known as the Unaka, or Smoky, +Chilhowee, Great and Little Frog, Nantahala, etc., all belonging to the +same family of hills. This chain has the same general course as the +Cumberlands. It is a much bolder range of mountains, but it is vastly +less inhabitable, productive, or convenient of access. The winters there +are severely cold, and the nights in summer are too cold and damp for +health and comfort, as I know by personal experience of two summers on +Nantahala River. But the trout fishing is beyond comparison, and that +is one inducement of great value for a stout consumptive _who is a good +fellow_. These mountains are much more broken up into branches, peaks, +and spurs than the Cumberlands. They afford no table terrritory of +any extent. There are some excellent places there for hot summer +visits--Ashville, Warm Springs, Franklin, and others. + +The Cumberland Mountains, as a whole, are flat, in broad level spaces, +broken only by the "divides," or "gulfs," as they are called by the +inhabitants, where the streams flow out into the valleys. + +Walden's Ridge, of which we come now to speak particularly, is the best +located of any part of the Cumberlands as a place for living. From the +separation of this ridge from the main range of Grassy Cove to its +southern terminus at the Tennessee River, it maintains a remarkably +uniform character in every particular. From it access to commerce is +easy, having the Tennessee River and the new (now building) Cincinnati +Southern Railroad skirting its entire length on the east. It rises very +abruptly from both the Tennessee and Sequatchee Valleys, being from +1,200 to 1,500 feet higher than the valleys on each side. Looking from +below, on the Tennessee Valley side, the whole extent of the ridge +appears securely walled in at the top by a continuous perpendicular wall +of sandstone, from 100 to 200 feet high; and from the Sequatchee side +the appearance is very similar, excepting that the wall is not so +continuous, and of less height. + +The top of the ridge is one level stretch of plain, broken only by the +"gulfs" before mentioned and an occasional prominent sandstone wall or +bowlder. The width on top is, I should judge, 6 or 7 miles. The soil is +of uniform character, light, sandy, and less productive for the ordinary +crops of the Tennessee farmer than the soil of the lowlands. The grape, +apple, and potato grow to perfection, better than in the valleys, and +are all never failing crops; so with rye and buckwheat. Corn grows +well, very well in selected spots, and where the land is made rich +by cultivation. The grasses are rich and luxuriant, even in the wild +forests, and when cultivated, the appearance is that of the rich farms +of the Ohio or Connecticut Rivers, only here they are green and growing +the greater part of the year; so much so that sheep, and in the mild +winters the young cattle, live by the wild grasses of the forests the +whole year. The great stock raisers of the Sequatchee and Tennessee +Valleys make this the summer pasture for their cattle, and drive them to +their own farms and barns or to market in winter. The whole Cumberland +table, with the exception of that small part which is under cultivation, +is one great free, open pasture for all the cattle of the valleys. +Thousands of cattle graze there whose owners never pay a dollar for +pasturage or own an acre of the range, though, as a rule, most of the +well-to-do stock farmers in the valleys own more or less mountain lands. +These lands have, until quite recently, been begging purchasers at from +12½ to 25 cents per acre in large tracts of 10,000 acres and upward, and +perhaps the same could be said of the present time, leaving out choice +tracts and easily accessible places, which are held at from 50 cents to +$2 per acre, wooded virgin lands. + +The forest growth of Walden's Ridge is almost entirely oak and chestnut. +Hickory, perhaps, comes next in frequency, and pine after. There is but +little undergrowth, and where the forests have never been molested there +are but few small trees. This is due to the annual fires which occur +every autumn, or some time in winter, almost without exception, and +overrun the whole ridge. It does not rage like a prairie fire. Its +progress is usually slow, the material consumed being only the dry +forest leaves and grasses. The one thing essential to its progress is +these dry leaves, hence it cannot march into the clearings. Nearly all +the small shrubs are killed by these fires, otherwise they are harmless, +and are greatly valued by the stock men for the help they render in the +growth of the wild grasses. The free circulation of air through these +great unbroken forests is certainly much facilitated by these fires, +since they destroy every year what would soon become impediments. The +destruction of this undergrowth leaves the woods open, and the lands are +mainly so level that a carriage may be driven for miles, regardless of +roads, through the forests in every direction. + +The shrubs about the fields and places where the forests have +been interrupted by civilization and other causes are blackberry, +huckleberry, raspberry, sumac, and their usual neighbors, with the +azalia, laurel, and rhododendron on the slopes and in the shade of the +cliffs. + +The kinds of wild grasses, I regret to say, I have not noted, and the +same of the rich and varied display of wild flowers. + +The whole ridge is well supplied with clean, soft running water, even +in the driest of the season. There are no marshes, swamps, or bogs, no +still water--not even a "puddle" for long--for the soil is of such a +character, that surface water quickly filters away into the sands and +mingles with the streams in the gulfs. Springs of mineral water are +abundant everywhere. Probably there is not a square mile of Walden's +Ridge which does not furnish chalybeate water abundantly. Sulphur +springs with Epsom salts in combination are nearly as common. + +The entire extent of Walden's Ridge is underlaid with veins of coal, and +iron ore is plentiful, especially in the foot hills. The coal and iron +are successfully mined in many places on the eastern slope; on the +western they are nearly untouched for the want of transportation. I find +that the impression prevails that the minerals of the Cumberlands are +largely controlled by land agents and speculators. This is only true as +applied to a very small part of the whole, not more than 1 per cent. The +mineral ownership remains with the lands almost entirely. + +The prevailing winds on Walden's Ridge are from the southwest; northers +and northeasters are of rare occurrence. One old lady who had resided +there for forty years, in answer to my query upon this subject, said: +"Nine days out of ten, the year round, I can smell Alabama in the air." +This was the usual testimony of the residents. Winds of great velocity +never occur there. In summer there is always an evening breeze, +commencing at 4 to 6 o'clock, and continuing until after sunrise +the next morning. In times of rain, clouds hang low over the ridge +occasionally, but they never have fogs there. + +The range of the thermometer is less on the Tablelands than in the +adjacent valleys. I have had access to the carefully taken observations +of the Lookout Mountain Educational Institute, such published accounts +as have been made by Professor Safford, State Geologist, Mr. Killebrew, +the thorough and painstaking private record of Captain John P. Long, +of Chattanooga, and many more of less length of time. From all these I +deduce the fact that the summer days are seven or eight degrees cooler +on the mountains than in the Tennessee Valley at Chattanooga, and five +or six degrees cooler than in the Sequatchee Valley, as far up as Dunlay +and Pikeville. The nights on the table are cooler than in the lower +lands by several more degrees than the days; how much I have thus far +not been able to state. The late fall months, the winter, and early +spring are not so much colder than the valleys as the summer months, the +difference between the average temperature of the mountains and valleys +being at that time four or five degrees less than in the summer. There +is no record of so hot a day ever having occurred on the Cumberladd +Mountains as to cause mercury to run so high as 95° F., or so cold a day +as to cause it to run so low as 10° below zero. + +In the average winter the ground rarely freezes to a greater depth than +2 or 3 inches, and it remains frozen but a few days at a time. Ice has +been known to form 8 inches thick, but in ordinary winters, 3 or 4 +is the maximum. Snow falls every winter, more or less, and sometimes +remains for a week. Old people have a remembrance of a foot of snow +which lasted for a week. + +Walden's Ridge has a total population of a little more than 4,000, +scattered over 600 square miles of surface. The number of dwellings is +about 800. Ninety per cent. of these are log houses; 70 per cent. of +them are without glass windows; light being furnished through the +doorways, always open in the daytime, the shuttered window openings, and +the open spaces between the logs of the walls. Less than 2 per cent. of +these houses have plastered walls or ceilings, and less than 5 per cent. +have ceiled walls or ceilings. About 20 per cent. of them are fairly +well chinked with clay between the logs, the remainder being but +indifferently built in that particular. Fully 90 per cent. of these +abodes admit of free access of air at all times of day and night, +through the floors beneath as well as the walls and roof above. It is +the custom of the people to guard against the coldest of days and nights +by hanging bed clothes against the walls, and many good housewives have +a supply of tidy drapery which they keep alone for this purpose. + +Wood, always at hand, is the only fuel in use. The whole heating +apparatus consists in one large open fireplace, built of stone, +communicating with a large chimney outside the house at one end, and +frequently scarcely as high as the one story building which supports it. +This chimney is constructed in such a manner as to be a great ventilator +of the whole room, quite sufficient, it would be thought, if there were +no other means of ventilation. It is usually made of stone at the +base, and that part above the fire is of sticks laid upon one another, +cobhouse fashion, and plastered over inside and between with similar +clay as that with which the house walls are chinked. + +Very few of these houses are more than one story high. They are all +covered with long split oak shingles--the people there call them +"boards"--rifted from the trunks of selected trees. There is no +sheathing on the roof beneath these shingles. They are nailed down upon +the flat hewn poles running across the rafters, at convenient distances. +Looking up through the many openings in the roof in one of these house, +one would think that this would be but poor protection against rain, but +they rarely leak. + +Not one family in fifty is provided with a cooking stove. They bake +their bread in flat iron kettles, with iron covers, covered with hot +coals and ashes. These they call ovens. The meat is fried, with only the +exception of when accompanied by "turnip greens." + +The question, "What is the principal food of the people who live on +these mountains?" has been asked by me several hundred times. The +almost invariable answer has been, "Corn bread, bacon, and coffee." +Occasionally biscuits and game have been mentioned in the answers. All +food is eaten hot. Coffee is usually an accompaniment of all three +meals, and is drunk without cream and often without sugar. Some families +eat beef and mutton for one or two of the colder months in the year on +rare occasions, though beef is commonly considered "onfit to go +upon," as I was told upon several occasions, and mutton sustains less +reputation. Chickens are used for food while they are young and tender +enough to fry, on occasions of quarterly meetings, visits of "kinfolks" +or the "preachers" and the traveling doctors. Fat young lambs are plenty +in many settlements from March to October, and can be had at fifty cents +each, but I could not learn that one was ever eaten. + +A large majority of the adult population use tobacco in some shape--the +men by chewing or smoking, the women by smoking or dipping snuff. They +never have dyspepsia, nor do they ever get flesh, after they pass out of +childhood, though nearly all the children are ruddy in appearance, and +well rounded with fat. + +One physical type prevails among the people in middle life, and carries +along into old age but little change; and old age is common there. +Nearly every house has its old man or old woman, or both. Everybody, +father and mother, and frequently grandfather and grandmother, is still +on hand, looking as brisk and moving about as lively as the newer +generations. After they pass their forty years, they never seem to +grow any older for the next twenty or thirty, and the grandfathers and +grandmothers can scarcely be selected, by comparison, from their own +children and grandchildren. The men are taller than the average, and +the women, relatively, taller than the men. They are all thin featured, +bright eyed, long haired, sharp looking people, with every appearance of +strength and power of endurance. + +I think the men who live on Walden's Ridge can safely challenge the +world as walkers--aborigines and all; and unless the challenge should be +accepted by their own women folks, I feel quite sure they would "win the +boots." They go everywhere on foot, and never seem to tire. + +Nearly all the people of the Tablelands are employed in the pursuits of +agriculture. Very few of them seem to be hard workers. The men are all +great lovers of the forest sports, much given to the good, reliable, old +fashioned long rifles. The women and children are much employed in out +door occupations, and live a great portion of their time in the open +air. The clothing of all classes is scanty. The use of woolen fabrics +for underwear has not yet been introduced, and coarse cotton domestic +is the universal shirting, and cotton jeans, or cotton and wool mixed, +constitute the staple for outer wearing apparel. The men wear shoes +throughout the year much more commonly than boots. They never wear +gloves, mittens, scarfs, or overcoats, and they scorn umbrellas. +Probably this whole 4,000 people do not possess two dozen umbrellas or +twice as many overcoats. The women go about home with bare feet a great +part of the summer. They never wear corsets or other lacing. + +I have learned by careful inquiry that very few of the people of the +Ridge have ever had the diseases of childhood. Scarlet fever I could +hear of in but two places, and I suppose that not one person in fifty +has had it. Whooping cough and measles have occurred but rarely, and the +large majority have not yet experienced the realities of either. Very +few people there have ever been vaccinated, nor has smallpox ever +prevailed. Typhoid, typhus, and intermittent fevers are unknown. In the +great rage of typhoid fever which took place ten or twelve years ago in +the Tennessee and Sequatchee Valleys, not a single case occurred on the +Mountains, as I have been informed by physicians who were engaged in +practice in the neighborhood at the time. Diphtheria has never found a +victim there; so of croup. Nobody has nasal catarrh there, and a cough +or a cold is exceedingly rare. + +I have said that these observations refer more particularly to Walden's +Ridge than to the Cumberland Tablelands in our State as a whole. This +ridge was chosen by me for this examination, mainly for the reason of +its convenience, but partly owing to its being more generally settled +than any other equal portion of the table which lies in Tennessee. +Lookout Mountain is not as well located; it is on the wrong side of the +Tennessee River, and but a few acres of it belong in this State. Sand +Mountain is altogether out of the State, but it is perhaps nearer like +Walden's Ridge in its physical features than Lookout. That part of the +Cumberlands west of Sequatchee Valley is Walden's Ridge in duplicate, +excepting that it is further west, and nearer the Middle Tennessee +basin. There are some small towns, villages of miners, and summer +resorts there, which interferes with that evenness of the distribution +of population which Walden's Ridge has, rendering it more liable to +visitations of epidemic and contagious diseases. The tablelands north +of the center line of the State, above Grassy Cove, are very similar +to Walden's Ridge, as far up as Kentucky, with the exception before +mentioned--that of climate--it being from one to ten degrees colder in +winter. + +This whole Cumberland Table is no small country. It comprises territory +enough to make a good sized State. At present, it is almost one great +wilderness, in many particulars as unknown as the Black Hills. It is +coming into the world now, and will be well known in a few years. The +great city of Cincinnati has determined to build a railroad through +the very center of this great table in the north part of the State, +connecting with Chattanooga in the southern part. This road is nearly +bored through, and in another year or two the Cumberland Tablelands in +Tennessee will be much heard of at home and abroad. + +It seems to me this country has merits. It is located in the latitude of +mild climate; not so far south as to be scorched by the hot summer sun, +or visited by the great life destroying epidemics; not so far north as +to meet the severe and lengthened winters. + +Climate, we know, is a fixture; it has a government; it has rules; the +weather may change, but climate does not; it is a permanent out-door +affair, and what is true of to-day was true centuries ago, and will +be true forever, in the measure of any practical scope, at least. The +people of the world are beginning to know that the greatest destroyer of +human life has its remedy in climate. + +Mr. Lombard, in his famous exhibit in relation to the prevalence of +consumption among the people of different occupations, circumstances of +life, and place of dwelling, gives the lowest number of deaths from this +cause to those who live in the open air. He found the people who lived +most in the open air, as would be readily conjectured, in the mild +latitudes, not in the countries of hot sands or cold snows. + +[The above article, in regard to which we have noticed frequent +allusions in many of our exchanges, all erroneously attributing it to +_Dr. Wright_, of Tennessee, and for which we have received repeated +requests quite recently, was read by the lamented Dr. E.M. Wight at +the 43d annual meeting of the Tennessee State Medical Society, held +at Nashville, April 4, 5, and 6, 1876. Its distinguished and talented +author will long be remembered as one of the most active, earnest, and +zealous members of the State Society. At this meeting he also read a +very admirable paper on "The Microscopic Appearance of the Blood in +Syphilis," and prepared the report of the Committee on State Board +of Health, to which report may be ascribed the honor of securing the +necessary legislation organizing the Board. A true, upright, honest man, +an earnest, devoted and zealous physician, universally esteemed and +beloved by all who knew him; himself the subject of tuberculosis, dying +in the prime of a brilliant manhood. He had but few equals in the +glorious profession he honored and loved so well. + +From a careful reading of his paper, we find that he describes a large +area of territory, free, absolutely free, from subsoil moisture, a +climate mild and equable, a soil capable of producing nearly everything +necessary for the comfortable maintenance of human life, surroundings +that tempt, nay, compel the greatest possible amount of open air +life. His description is exceedingly accurate of a plain, primitive, +simple-minded people with but few wants, many of the virtues and few +of the vices of humanity. With their surroundings, soil, climate, +residence, and mode of living, need we be surprised that "there is +a people," or a land "free from consumption"?--ED.]--_Southern +Practitioner_. + + * * * * * + + + + +THE TREATMENT OF HABITUAL CONSTIPATION. + + +Dr. F.P. Atkinson thus writes in the _Practitioner_, January, 1884: I +suppose there is no derangement of the system we are more frequently +called upon to treat than habitual constipation; and though all kinds of +medicines are suggested for its relief, they rarely produce more than +temporary benefit--and it is difficult to see how the result can well be +otherwise, while the root of the evil remains untouched. Now by far the +more numerous subjects of this disorder are women; and as they do not +seem to know that regularity is essential to the performance of every +one of nature's operations, they appoint no stated times for trying to +get the bowels relieved, but trust to receiving intimation when the +rectal accumulation and distension can be borne no longer. This method +of action may and does answer fairly well for a time; but nature +gradually gets upset, the sensation of the lower bowel becomes blunted, +and at last it ceases to respond to the ordinary stimulus. Then +aperients are regularly resorted to, and although these act fairly +well for a time, they gradually have to be increased in strength +and frequency. Now, as regards the treatment, the first thing to be +accomplished is of course to get the rectum well relieved; the next, +to get the actions to take place at fixed times; and lastly, it is +necessary to get more tone imparted to the muscular tissue of the +bowels, so that the regularity of action may be helped and also +maintained. In order, then, to get the bowels relieved in the first +instance, it is well to give five grains of both compound colocynth and +compound rhubarb pill at bed-time (this rarely requires to be repeated), +then to take a tumblerful of cold water the next morning on waking, and +repeat it regularly at the same time each day. Should the bowels remain +sluggish for some time, the same quantity of water may be taken daily +before each meal. Supposing no action takes place on rising or shortly +after, a small injection of warm water may be resorted to. After each +movement of the bowels, a small hand-ball syringeful of _cold_ water +should be thrown into the rectum and retained. A soup plateful of coarse +oatmeal porridge (made with water and taken according to the Scotch +method, viz., by filling half the spoon with the hot porridge and the +other with cold milk) each night at bed-time, or even every night and +morning for a time, is often a very great help. But above all things, +it is necessary for the patient to _try_ and get relief at a certain +_fixed_ time regularly every day. If these directions are strictly +carried out in their entirety, the evil, even if it has been of long +standing, will generally be corrected, and the patient will improve in +health and appearance. Of course where the constipation results from +exhaustion of the nervous system (such, for instance, as is brought +about by self-abuse), the special cause has to be taken into +consideration, and such treatment adopted as is suited to the particular +necessities of the case. + + * * * * * + + + + +THE PYRAMIDS OF MEROE. + + +About fifty miles from the mouth of the Atbara, and, of course, on the +eastern bank of the Nile, stand the pyramids of Meroe. They consist +of three groups, and there are, in all, about eighty pyramids. The +presumption is that they represent the old sepulchers of the kings of +Meroe. Candance, Queen of the Ethiopians, mentioned in Acts, chap. +viii., v. 27, is supposed to have belonged to Meroe, that being the name +also of the capital, which is understood to have been somewhere not far +distant from the sepulchers. These pyramids of Meroe possess one marked +feature, distinguishing them from the pyramids of Egypt proper--that is, +they have an external doorway or porch. As there is no entrance to the +pyramid at these porticoes, it is quite possible that they were temples +for worship or making offerings to the dead. By comparing them with +the pyramids of Ghizeh, it will be seen that they are also taller in +proportion to their base. Another important point in these porches +or temples is the existence of the arch; and that, too, an arch in +principle, with a keystone.--_Illustrated London News_. + +[Illustration: THE PYRAMIDS OF MEROE, ON THE NILE.] + + * * * * * + + + + +THE PROLIFICNESS OF THE OYSTER. + + +In an article by Prof. Karl Mobius on "The Oyster and Oyster Culture," +reproduced in the recently issued report of the U. S. Commissioner of +Fish and Fisheries, the author says: + +A mature egg-bearing oyster lays about one million of eggs, so that +during the breeding season there are upon our oyster beds at least +2,200,000,000,000 young oysters, which surely would suffice to transform +the entire extent of the sea-flats into an unbroken oyster bed; for if +such a number of young oysters should be distributed over a surface 74 +kilometers long by 22 broad, 1,351 oysters would be allotted to every +square meter. But this sum of 2,200,000,000,000 young oysters is +undoubtedly less than that in reality hatched out, for not only do those +full-grown oysters which are over six years of age spawn, but they begin +to propagate during their second or third year, although it is true that +the young ones have fewer eggs than those which are fully developed. At +a very moderate estimation, the total number of three to six year old +oysters which lie upon our beds will produce three hundred billions of +eggs. This number added to that produced by the five millions of full +grown oysters would give for every square meter of surface not merely +1,351 young oysters, but at least 1,535. In order to determine how +many eggs oysters produce, they must be examined during their spawning +season. This begins upon the Schleswig-Holstein beds in the middle of +June, and lasts until the end of August or beginning of September. The +spawning oyster does not allow its ripe eggs to fall into the water, as +do many other mollusks, but retains them in the so-called beard, the +mantle, and gill-plates until they become little swimming animals. The +eggs are white, and cover the mantle and gill-plates as a semi-fluid, +cream-like mass. As soon as they leave the generative organs the +development of the germ begins. The entire yolk-mass of the egg divides +into cells, and these cells form a hollow, sphere-like body, in which an +intestinal canal arises by the invagination of one side. Very soon the +beginnings of the shell appear along the right and left sides of the +back of the embryo, and not long afterward a ciliated pad, the velum, is +formed along the under side. This velum can be thrust out from between +the valves of the shell at the will of the young animal, and used by the +motion of its cilia as an organ for driving food to the mouth, or +in swimming as a rudder. During these transformations the original +cream-white color of the germ changes into pale gray, and finally into a +deep bluish-gray color. At this time they have a long oval outline, and +are from 0.15 to 0.18 of a millimeter in breadth. Over 300,000 can find +room upon a square centimeter of surface. If an oyster in which the +embryos are in this condition is opened, there will be found upon its +beard a slimy coating thickly loaded with grayish-blue granules. These +granules are the embryo oysters, if a drop of the granular slime be +placed in a dish with pure sea water, the young animals will soon +separate from the mass, and spread swimming through the entire water. +When the embryos are at this stage their number may be estimated in the +following manner: The whole mass of embryos is carefully scraped from +the beard of the mother oyster by means of a small hair brush. The whole +mass is then weighed, and afterward a small portion of the mass. This +small portion is then diluted with water or spirits of wine, and the +embryos portioned out into a number of small glass dishes, so that they +can be placed under the microscope and counted. Thus, knowing the weight +of the small portion and the number of embryos in it by count, we can +estimate the total number of embryos from the weight of the entire mass, +which is also known. In this manner I estimated the number of embryos +in each of five full grown Schleswig-Holstein oysters caught in August, +1869, and found that the average number was 1,012,956. + +Notwithstanding this great fecundity, but an extremely small proportion +of the young oysters produced during the course of the summer arrive +at maturity, 421 only out of 500,000,000 escaping destruction. The +immolation of a vast number of young germs is the means by which nature +secures to a few germs the certainty of arriving at maturity. In order +to render the ideas of germ-fecundity and productiveness more easily +understood, Prof. Mobius makes the following comparison between the +oyster and man: + +According to Wappaus, for every 1,000 men there are 347 births. +According to Bockh, out of every 1,000 men born 554 arrive at maturity, +that is, live to be twenty years or more of age; thus, on an average, +347 children are produced from 554 mature men, or 626 children from +1,000 mature men. Since 1,000 full-grown oysters produce 440,000,000 of +germs, then the germ fecundity of the oyster is to the germ fecundity of +man as 440,000,000 to 6.26, or as 7,028,754 to 1. On the other hand, the +number which arrive at maturity is 579,002 times as great with mankind +as with the oyster; for of 1,000 human embryos brought into the world +554 arrive at maturity, or of 440,000,000 newly born 243,760,000 would +live to grow up, while of 440,000,000 young oysters only 421 ever become +capable of propagating their species. The proportion is then 421 to +243,760,000, or as 1 to 579,002. I am fully persuaded that these figures +represent the number of oysters which arrive at maturity more favorably +than is really the case, since from every thousand of full grown oysters +it is certain that, on an average, more than 440,000,000 young are +produced. + + * * * * * + + + + +RED SKY. + + +The beautiful red sky which has been so frequent of late, morning as +well as evening, has excited much comment. The comment, however, has +consisted more of description, statement of fact, theory, and wonder as +to cause, rather than as to satisfactory explanation. + +Facts in the case which would reveal the secret of this beautiful +display of nature are not complete and numerous enough at present to +establish the cause of this phenomenon on a sure basis; yet enough +facts, it would seem, have been obtained to satisfy the strong mind +capable of bridging over a wide expanse. + +Facts in an argument are like piers to a bridge-the more we have of +them, c. p., the more substantial the structure. When the facts are +_legion_, the structure becomes a causeway, and there is no need of +argument. + +Argument is a bridge--the fewer the facts, the more the necessity for +the bridge; the less the facts, the more argument necessary to connect +the few we have, and the more skill is required to make substantial +connecting links between the few solid piers (facts) that exist. + +One of the queer things in connection with this is, the public have +looked chiefly, if not wholly, to the astronomers for an explanation +of this phenomenon, when it is not their special province to explain +matters in this department of nature. + +The explanation belongs to the department of meteorology, and not to +astronomy. But the fact of having looked to the astronomers shows how +little the world knows of meteorology and how few meteorologists +there are able, ready, and willing to rise and explain in face of the +opposition of the public, who seem to think that the explanation must +necessarily belong to astronomy. Astronomy proper deals with the +position of the earth in space and its relation to the other heavenly +bodies, whether suns, fixed stars, planets, satellites, comets, or other +bodies in the vast space about us. Meteorology deals with the atmosphere +of the globe, in all its forms. Astronomy could be studied in the early +ages; its grand facts were not wholly dependent upon the advanced +condition of the mechanic arts; it could be studied even without the aid +of telescopes, though telescopes have added much to its advancement. +Meteorology, on the contrary, depended on the advancement of the arts +and sciences; they must first be perfected ere we could know much about +this branch of science. To one unfamiliar with the advancement and +perfection of meteorology within the past ten years, this statement +may seem strange, yet it is an undisputable fact that, prior to the +establishment of the daily weather reports, the knowledge on this +subject amounted to very little, and was not even worthy of being +designated a science. Prior to the advent of the weather map the world +was in absolute ignorance of the laws governing the atmosphere. Sure, we +had had large volumes on the laws of storms, but the later revelations +leave them shelved high and dry on the shores and as useless as a wreck +in a similar condition; with the daily weather map before us we have no +need to even open these huge volumes; they are completely circumvented, +and only negative in value--to show how little was known of the subject +without the full and complete facts daily collected and spread before us +on the map published by the Weather Bureau. + +In order to understand the color of our sky, we must understand the +subject which is so immediately connected with it and its creation. + +The earth is a sphere in space; generally speaking, it is composed of +land and water. These are two factors; the heat that it derives from +the sun forms a third factor; the three--land, water, and heat--are +essential to life, at least the higher conditions of life which +culminate in man. The old physical geography taught us this much, but +it was not able to go further and tell us why it was cold or warm +independent of the seasons; it could not explain why it was at times as +warm, and even warmer, half-way to the pole than at the equator; why it +was at times very warm in the extreme northeast while very cold in +the Southern States; cold in the northwest when it was warm in the +northeast, and warm in the northwest when cold all along the upper +Atlantic seaboard; it could not forewarn us of storms. These and a +host of other facts, which the weather map makes as plain as astronomy +demonstrates that Jupiter is a planet, the new revelation, through the +instrumentality of the perfected telegraph system, makes exceedingly +plain to us if we will but seek the easily obtained information. + +The principal revelations of the weather map are the facts in regard to +the areas of high and low barometer, and the influence they exert upon +the climate of the globe. + +These conditions--high and low barometer--move on general lines from the +west towards the east, or towards the rising sun, and around the world +in irregular belts. The centers of low barometer are various distances +apart, from a thousand to two thousand and even more miles apart--call +the average about two thousand miles. + +The clouds are formed from the moisture present by the action of the +sun's heat. The direction of the wind is from the area of high barometer +to that of low. The nearer the winds approach the center of "low" (low +barometer), the more they partake of the lines of the volute curve, or +curve of the sea shell or water in a whirlpool. High barometer is the +atmospheric hill; low barometer is the atmospheric valley. But time at +present will not permit more than these general statements; a close +study of the weather map for a season will reveal the beautiful minor +details. + +To the reader it may seem a long way round, yet in order to fully +understand the nature of the atmosphere which surrounds our globe we +must pay due attention to these newly discovered physical laws. + +The red sky which was so noticeable, in the fall of 1883, the +astronomers have told us was due to "meteoric dust" which was produced +by the volcanic eruption on the island of Java, August 27, 1883. + +This "meteoric dust" they say combined with the atmosphere, followed it +around the earth, and caused the beautiful redness of the sky at morning +and evening. For one, I do not believe dust of any description in the +atmosphere would produce such an effect. + +There is nothing luminous, transparent, or delicate about dust. Dust +would not remain in the atmosphere for months, it would settle in a very +short time, and if thick enough in the atmosphere to obstruct the light +of the sun it would be visible, discernible, to the eye, and manifest +on the face of nature. Years ago, before the age of the weather map, we +might have thought that the atmosphere followed the surface of the earth +like the water on a grindstone, but it does not. As already seen, the +wind is from the area of high barometer to that of low, and there are +many of these "low centers." + +From the best calculation we can make at present, there would be at +least some six centers on an average between the center of the United +States and the island of Java. In addition to this there would also be +a number of belts of "low" centers, which would complicate the thing +threefold at least. At all these different centers the winds would be +blowing from all points of the compass at the same time. Such winds +would not be apt to bring the "meteoric dust" from Java to the United +States, either in an easterly or westerly direction. But, it is said, +"dust" has been gathered. + +How high from the surface of the ground has this _dust_ been +gathered--at what elevation? + +There is undoubtedly a little dust in the air most of the time, but I do +not think that it extends very high. Where it would be the highest and +most perceptible would be on the arid plans of Africa and Asia, when +the _simoom_ is passing, or in the track of a tornado. But from the +multiplicity of these storm centers and the varied winds they would +produce even this dust could not travel from Java to America. + +Again, all clouds, no matter how high or how low, are affected by the +low centers, as the movement of clouds prove, and travel from the "high" +to the "low," from and to all points of the compass. High authority +gives the heights of the clouds as follows: lower clouds, 16,000 feet; +upper clouds, 23,000 feet. + +As all clouds, from the highest to the lowest, are affected by the +centers as above referred to, it follows that if this "meteoric dust" +follows the earth around, as it would have to do in order to make good +this theory, it would have to travel suspended in the atmosphere above +the upper clouds, or at a height of more than 23,000 feet, or at an +elevation of over four miles! + +Now, is it reasonable to believe that dust, however fine, will remain in +the atmosphere at that elevation for over six months? + +As a side argument it is suggested that the smoke of the burning woods, +or few years ago in Michigan, caused as peculiar condition of the +atmosphere. This extensive fire was on a day when the area of low +barometer was on a high line of latitude and passing to the eastward. +This naturally took the smoke, which is far lighter than dust, along +with it. It mingled with the muggy condition of an extensive "low," and +produced a yellowness of the atmosphere. This however was of only a few +hours' duration, and was only visible in favorable localities. + +Here again we see the advantage of the weather maps; but for this map we +would never have been able to have satisfactorily explained the peculiar +phenomenon produced by the great Michigan fire. + +If the delicate redness of the sky is not caused by dust, what is it +caused by? + +But for the weather map, I think we should still be in the dark in +regard to it. + +In the first place, this redness is nothing new, only the conditions +are more favorable sometimes than at others. It has always existed and +always will exist, independent of earthquakes, volcanoes, etc. Nature +is ever changing; the movements of the atmosphere more resemble the +kaleidoscope than any thing else. + +The summer and fall of 1883, the movements of "high" (high barometer) +over the United States were quite central and extensive, causing this +peculiar phenomenon over a wide extent of territory. + +We have no information of the condition of the barometer over the other +part of the world; we speak move particularly of the United States; yet +if certain conditions produce certain effects here, it is quite safe to +say that the same effects are produced by the same cause elsewhere. + +As now well established by the map, the surface wind is from the area +of high barometer to that of low--from the atmospheric hill to the +atmospheric valley. + +The tendency of this is to free "high" of all clouds and moisture; but +then it is impossible to free "high" entirely of moisture; a little +will remain, and it is just this little, which is highly rarefied, that +produces the result. We look around us and above, we see little or no +evidence of evaporation, yet it is the while going on. When the sun is +immediately below the horizon, where it will shine horizontally through +the mass of light, suspended moisture, the delicate presence of vapor +heretofore unnoticed is revealed. The action of the sun's rays is the +same as when illuminating a well formed cloud--it is an embodiment +of the same principle, but the material is much more expanded. The +particles of suspended moisture are very fine, few and far between, +therefore the effect of the light upon it is more diffused and +transparent. It is much like looking through a piece of window glass +flatwise and endwise; flatwise we do not perceive any color; endwise, +from seeing through a greater mass, the glass has a very perceptible +green color. + +We see the same idea also in the rising and setting sun and moon. On +a clear, cloudless night, when nothing seems to interfere with the +brightness of the stars, we cannot, by looking upward, perceive any +moisture present in the atmosphere; but if we cast our eyes to the +horizon, whereby we see through the mass of atmosphere endwise, as it +were, and note the appearance of the stars there, or the rising or +setting moon, we will see that the atmosphere there gives a redness +to the rising body, which it does not have when it has ascended to +mid-heaven. On a clear night, which is caused by the presence of the +area of high barometer, the moon when in mid-heaven is of a clear, +silver-white, and it is the same moon that at the horizon was a deep +red. The color of the moon has not changed; it is simply the medium +through which it is seen that produces the difference in color. + +Occasionally, on a clear, bright ("high") night, when the moon is full, +prior to rising, when just below the horizon, it will so illuminate this +lower strata of atmosphere as to appear like a great fire; the moon +rises red, but its deep color gradually fades as it rises, and when well +up in the heavens we perceive that this deep coloring was an illusion +and merely the influence of its surroundings. I never, though, knew of +any one to attempt to account for this by "meteoric dust;" and yet it is +an embodiment of the same principle. Place the sun where the moon is, +and from its far superior abundance of light we have a much grander +display. + +Under no other conditions or relations of the sun and earth is it +possible to have this phenomenon of the delicate red sky but when a +positive area of high barometer is passing and extends over us. In +order to produce this effect we must have the clear atmosphere of high +barometer, when there is a minimum of moisture present. The action of +the sun's rays upon this extensive area of slightly moist rarefied +air is unconfined by clouds, and reaches far and wide, and produces +a delicacy of color which from no other source or condition can be +realized. + +ISAAC P. NOYES. + +Washington, D. C., 1884. + + * * * * * + + + + +A THEORY OF COMETARY PHENOMENA. + + +_To the, Editor of the Scientific American_: + +The following subject, substantially, was written more than a year ago +with a view to its publication. It was not, however, until January of +the present year that I sent a brief communication to the _Brooklyn +Eagle_, which was published Feb. 3, giving my views in relation to +cometary phenomena. With this I might remain satisfied, were it not +that the interesting paper by G. D. Hiscox, published in the SCIENTIFIC +AMERICAN SUPPLEMENT, Feb. 16, impressed me with the idea that the theory +I advanced might assist in explaining others, if brought to the notice +of those interested through the columns of your valuable journal. + +The theory that I advance to account for the several phenomena relating +to comets' tails is, that comets are non-luminous, transparent bodies; +that they transmit the light of the sun; that the transmitted light +reflected by the particles of matter in space constitutes the tails of +comets. "Like causes produce like effects." By contraries, then, like +effects must be produced by similar causes; for, if an effect produced +by a cause which is known is similar to an effect produced by a cause +which is not known, the cause which is known must be similar to the +cause which is not known. This is true or not. + +I submit the following experiments to substantiate the theory advanced. + +Partially fill a vial or a tumbler with water, hold it by the rim, +and move it around a lighted candle placed upon a table. A shadow +surrounding the transmitted light will be cast upon the table. As the +tumbler approaches the light, the shadow follows the tumbler, and when +receding the tumbler follows the shadow; and as the tumbler is moved +around the light, the shadow will swing round from one side to the +other. If the tumbler be held so that a puff of smoke can be blown +into the transmitted rays, the particles of smoke will reflect the +transmitted light, and will illustrate my idea of what constitutes a +comet's tail. A dark band may be observed in this stream of light, as +also in the light cast upon the table. + +In these experiments, we see the effects produced by a cause which is +known; the effects are similar to those observed in the tails of comets, +the cause of which we do not know; but is it not reasonable to assume +that the cause is similar? + +Assuming now that comets are transparent, can any other phenomena +peculiar to comets be accounted for upon this hypothesis? Next to +the tail itself, the curve is the most noticeable feature, and if we +consider the extraordinary length of these appendages, the astounding +velocity at which comets move in their orbits, and the time that would +elapse before a ray of light, emitted from the nucleus, would reach the +end of the tail, perhaps the curve--which, if I am not deceived in my +observations, always dips toward its orbit--can be accounted for. If a +comet moved in a direct line toward the center of the sun, there would +be no curve to the tail. But taking Donati's comet of 1858 as an +example, the tail of which was said to be about 200,000,000 miles long, +a ray of light traveling at the rate of 192,000 miles per second would +be about twenty minutes in going from the nucleus to the end of the +tail. + +But during that time the comet would move in its orbit, say, 50,000 +miles, and as light moves in a straight line, and other rays are +constantly emerging from the nucleus as it moves along in its course, +the result is that the tail has a curved appearance. + +I have no data at hand regarding this comet, but what I have said will +serve to illustrate my ideas. Again, referring to this comet, I remember +to have read the statement of an astronomer that, after passing round +the sun, a new tail was formed opposite the original one. Now, it seems +to me that that is just what would happen, for in moving round the sun +the comet would travel say 3,000,000 miles; the greater portion of the +tail then, would extend millions of miles upon one side of the sun, +while from the nucleus upon the opposite side of the sun a new tail +would appear to be formed. + +Upon this hypothesis, the extraordinary length of their tails and the +fact that stars are visible through the densest portion of them is +explained; as also the fact that they so rapidly disappear from view +when moving from the sun, the light received by them from the sun +being in proportion to their distance from it, and but little of that +reflected. + +JOHN M. HUGHES. + +Brooklyn, N. Y. + + * * * * * + +[FOR THE SCIENTIFIC AMERICAN.] + + + + +ON COMETS. + + +When we see a comet approaching the sun with its tail following in the +orbit of the nucleus, we have no great difficulty in believing the +common theory that a comet consists of nucleus attracted toward the sun, +while the tail is repelled; and that we see the whole of it. But as it +approaches the sun, difficulties arise that make us doubt whether the +theory be true. + +Let us suppose a comet with a tail 50,000,000 miles in length, and that +it will require two days to pass round the sun. Now the tail, being +always in a line drawn through the center of the sun and center of the +nucleus, will, when it reaches the long axis of the elliptical orbit, +stand perpendicularly to the orbit of the nucleus. That is, the +extremity of the tail farthest from the sun, in addition to its onward +motion, has acquired a lateral motion that has lifted it 50,000,000 +miles in the first day of its perihelion. The velocity of the extremity +has been vastly accelerated over that of the nucleus, and it has +moreover a sheer lift above the orbit of the nucleus. Now this lift is +in opposition to gravity; neither is it in consequence of any previous +momentum, for its velocity is accelerated and its previous momentum +would be a hindrance; nor is the lift in consequence of any repelling +force from the sun, for such force would be diminished in proportion to +the square of the distance, and the far end would be acted on less than +the nucleus end of the tail, whereas the velocity of the former is +increased a hundred fold over that of the latter. A polar force in the +comet would merely draw the comet into the sun. We therefore find no +force adequate for such a lift, but on the contrary all the forces are +opposed to it. + +But if the first day of the perihelion overwhelms us with difficulty, +the second day will prove disastrous to the common theory. For the +extremity of the tail farthest from the sun will be required to pass +with lateral motion from its perpendicular 100,000,000 miles, so that it +may be in advance of the nucleus and again rest on its orbit. This orbit +is an impassable line, and therefore instantly arrests the prodigious +lateral velocity of the tail. That impassable orbital line is to it +as solid and inflexible as a wall of adamant. The motion so instantly +arrested would be disastrous to any tail, whether composed of gas, +meteorites, or electricity, whatever that may be. + +Having shown that the common theory of comets is filled with insuperable +difficulties, I will again call attention to a theory proposed about +eighteen months ago in the SCIENTIFIC AMERICAN. + +According to this theory, a comet consists of a nucleus and an +atmosphere, for the most part invisible, surrounding it on all sides to +an extent at least equal to the length of the tail. The rays of the sun +in passing through or near the nucleus are so modified as to become +visible in their further progress through the cometic atmosphere, while +all the rest remain invisible. What we call the tail is merely a radius +of the cometic atmosphere made visible, and as the comet moves through +space, only different portions of the atmosphere come in sight, in +obedience to the ordinary laws of light. There is no difficulty in +accounting for the rise and fall of the tail at perihelion, nor for the +tail preceding the nucleus afterward. + +The spherical theory accounts easily for the different forms of tail +seen in different comets. The sword shaped tails, at variance with the +common theory, can be accounted for by supposing a slight difference in +density or material in the cometic atmosphere, which will deflect the +light as seen. The comet of 1823, which cannot be explained on the +common theory, is very easily explained on the spherical. That comet +showed two tails, apparently of equal length, which moved opposite to +each other, and perpendicularly to the orbit of the nucleus, and showing +no signs of repulsive force from the sun. On the spherical theory it is +only necessary to suppose such an arrangement of the nucleus as would +reflect the rays of the sun laterally; a slight modification of the +nucleus would give not only two but any number of tails pointing in +different directions. + +It may be objected to the spherical theory that a tail 50,000,000 miles +long would call for a sphere 100,000,000 miles in diameter, and that +would be too vast for our solar system. But it is claimed for this +sphere that it consists of the same material as the so-called tail, and +that it has the same capability of moving among planets without manifest +disturbance to either. + +The sphere at the perihelion would envelop the sun, and as a noticeable +reduction is sometimes found in its so-called tail, the cometic +atmosphere may impart to the sun at that time whatever is necessary to +its use. + +That there is something in common between the sun's corona and cometary +matter was shown by the last solar eclipse observed in South Pacific +Ocean, where the spectrum of sun's corona was found to be the same as +that of a comet's tail. Are we to attribute in any degree the different +appearances of the sun's corona to the presence or absence of a comet +at its perihelion? At the eclipse of the sun seen in Upper Egypt two or +three years ago, a comet was seen close to the sun, but I have seen no +account of the appearance of the corona at that time. + +FURMAN LEAMING, M.D. + +Romney, Tippecanoe Co. Indiana. + + * * * * * + + + + +FORMS OF IVY. + + +It is scarcely possible for us to bee too emphatic in our praises of the +most distinct forms of ivy, since but few other hardy climbing plants +ever give to us a tithe of their freshness and variety. A good long +stretch of wall covered with a selection of the best green-leaved kind +is always interesting, and never more so than during the winter months, +especially if at intervals the golden Japanese jasmine is planted among +them or a few plants of pyracantha or of Simmon's cotoneaster for the +sake of their coral fruitage. The large-leaved golden ivy is also very +effective here and there along a sunny wall, especially if contrasted +with the small-leaved kind--atropurpurea--which has dark purple or +bronzy foliage at this season. Of the large-leaved kinds, one of the +most distinct is canariensis, or large-leaved Irish ivy, and Raegner's +variety, with leathery, heart-shaped foliage, is also handsome. The +birdsfoot ivy (pedata) is curious, as it clings to the stones like +delicate leaf embroidery, and for shining green leafage but few equal +to the one called lucida. The two other kinds sketched are hastata and +digitata, both free growing and distinct sorts. + +[Illustration: VARIOUS FORMS OF IVY. Heart-leaved Ivy (Hedera +Raegenerana). Glossy Ivy (H. lucida). Arrow-leaved Ivy (H. hastata).] + +_Ivy Leaves_.--Common ivy is tolerably plentiful nearly everywhere, but +it is not common to find a good distinct series of its many varieties +even in the best gardens. Of all the different forms of ivy, I think +the large-leaved golden one of the best; certainly the best of the +variegated kinds. Raegner's variety is also very bold, its great glossy, +heart-shaped leaves most effective. Algeriensis is another fine-leaved +kind, the form dentata producing foliage even still larger when well +grown. For making low evergreen edgings on the turf, for carpeting +banks, the covering of bare walls and the old tree stumps, we have no +other evergreen shrub so fresh and variable, or so easily cultivated as +are these forms of the ivy green. Perhaps one reason why the finer kinds +of ivy are comparatively uncommon is the fact that a strong prejudice +exists against ivy in many minds. It is an erroneous notion that ivy +injures buildings against the walls of which it is planted; it never +injures a good wall, nor a sound house, but on the contrary, hides and +softens the stony bareness of the one and adds beauty and freshness to +the other.--_The Garden_. + +[Illustration: VARIOUS FORMS OF IVY. Finger-leaved Ivy (H. Itata). Irish +Ivy (H. canariensis). Rira's foot Ivy (H. pedata).] + + * * * * * + + + + +PROPAGATING ROSES. + + +In an article on this subject an English horticultural journal describes +the method pursued by a London florist. After stating that out of a case +containing 310 cuttings only five failed to root, the article proceeds: +The case or box is made of common rough deal boards. It is five feet +six inches long and one foot in depth. Within half an inch of the top a +groove is cut inside the box, into which the glass is slid, after the +manner of a sliding box lid. In the end of the third week in July the +box was placed in the kitchen garden under the shadow of a high north +wall; it was then about half filled with good turfy loam, to which had +been added a little leaf mould and a good sprinkling of sharp sand. The +soil was then pressed down very firmly (the box being nearly half full +when pressed), and then thoroughly well soaked with rain water, and +allowed to stay uncovered until the next day. The next day good stout +cuttings were taken of all the roses, both tea and hybrid perpetual, +which it was desired to add to the stock. They were then inserted +closely and firmly in the soil, just over the bottom leaf, the glasses +were slipped on and puttied down; the grooves in which the glass slid, +and even the joints in the glass, being filled with putty, so as to +exclude the air. The whole thing completed, nothing more remained to be +done but to leave the box in its cool, shady nook for five or six weeks, +when the growing points of the free starting kinds gave notice that the +glasses might be removed, a bit at a time, with safety. Nothing could be +more simple, or demand less skill, and the operation may be carried out +successfully by an amateur at any time during the season, when good firm +cuttings can be got, and when six weeks' tolerably fine weather may be +counted on. The success of the whole thing depends on having the glasses +fixed so that they may not be removed until the cuttings are rooted, and +in placing the boxes in a shady place. So treated, carnations and many +of our shrubs and herbaceous perennials may be propagated by unskilled +persons with certainty, and without much trouble. + + * * * * * + + + + +A FEW OF THE BEST INULAS. + + +Of the fifty-six species of Inula described in scientific works, +probably not more than thirty are at present in cultivation in +this country, and those are chiefly confined to botanic gardens, +notwithstanding the fact that many of them are useful garden plants. +They are principally distributed throughout Southern Europe, although we +find them extending to Siberia and the Himalayas; indeed, it is to the +Himalayas we are indebted for the kinds that are most ornamental. Some +of the low-growing species are extremely useful for the rockery, such +as I. montana (the Mountain Inula), a fine dwarf plant with woolly +lanceolate leaves and dense heads of orange-colored flowers, resembling +in habit and general appearance some of the creeping Hieraciums. It is a +handsome and desirable plant for the decoration of old walls and similar +places, where it can be a little sheltered from rain and drip. Another +very useful species for this purpose is I. rhizocephaloides, found +plentifully in the Himalayas. It is one of the prettiest Alpine +composites we have. It seldom attains more than from one inch to two +inches in height, forming a dense rosette of short, hairy, oval leaves, +in the center of which the bright purple involucres, in the form of a +ball, are extremely interesting. It is easily cultivated, requiring, +however, a rather snug nook, where it will not be allowed to become too +dry. It is best propagated from seed. Then there is the woolly Inula (I. +candida), a pretty plant with small oval leaves, covered with a thick, +silky down, and much in the way of the white-leaved I. limonifolia, both +of which are very effective when grown in masses, which should always +be low down near the front of a rockery, or as an edging for a mixed +border. The glandular-leaved Inula (I. glandulosa), of which a good +representation is here given, is a beautiful hardy perennial. It is a +native of Georgia and the Caucasian Alps, near the Caspian Sea. It is +a rather robust-growing species, with large, bright, orange-yellow +flowers, varying from three to five inches in diameter, the narrow and +very straggly ray florets contrasting nicely with the rather prominent +disk. The leaves, although quite entire, seem notched, owing to large +black glands which form on their margins. They are lanceolate, and clasp +the stem. The plant is very variable, both as regards robustness and +size of flowers, and this may in a measure account for the confusion +existing between it and I. Oculus-Christi. + +The soil most suitable for the full development of I. glandulosa is a +strong, clayey, retentive loam; it does not thrive well in the light +shallow soils in the neighborhood of London, except in shady positions. +I. Hookeri is a free-flowering perennial, with pointed lanceolate +leaves, of a delicate texture, bright green, and very finely toothed. +The flowers, which are sweet-scented, are not so large as those of I. +glandulosa, and are produced singly, the ray florets being, however, +much more numerous, rarely numbering less than thirty. It is found in +abundance in rocky places in Sikkim, where it replaces the nearly allied +I. grandiflora, a dwarfer species, with much shorter, shining leaves; +both are very desirable plants either for rockery or flower border work. +The Elecampane (I. Helenium) is an imposing, robust-growing species, +having large, broad leaves a foot or more in length. It grows from four +feet to five feet in height, and its thick, shaggy branches are crowned +with large yellow flowers. For isolating in woods this plant, is very +useful, and with the exception of Telekia cordifolia, it would be hard +to find a rival to it. It is, I believe, pretty extensively used for +planting in shrubberies, but unless they are thin and open it is seldom +seen to advantage. It is found wild or naturalized in some parts of +England. It flowers in June and July, and even into August when the +season has been favorable. + +[Illustration: INULA GLANDULOSA (_flowers deep yellow_.)] + +For naturalizing in woods the following will be found useful, _viz_., I. +salicina, I. Oculus-Christi, I. squarrosa, I. britannica, and many more, +the true beauty of which can only be realized in this way. With the +exception of I. rhizocepbaloides, they are all propagated by division +with the greatest ease, or by seed, which is best sown as soon as it is +ripe.--_D.K., The Garden_. + + * * * * * + + + + +FRUIT GROWING. + +By P.H. FOSTER. + + +In the first place, if you contemplate appropriating a portion of your +land for the raising of fruits, you should have the orchard so situated +that no large animals can run at large on the grounds. Prepare your soil +in the most thorough manner; underdrain, if necessary, to carry off +surplus water; dig deep, large holes; fill in the bottom with debris; +in the very bottom put a few leaves, clam and oyster shells, etc., then +sods; above and below the roots put a good garden or field soil; do not +give the trees fresh manure at the time of setting, but the following +fall manure highly with any kind on top of the ground; dig it in the +following spring; keep the soil frequently worked during the summer, +and, if convenient, mulch with hay, straw, or leaves. + +Now you are on the road to progress, provided you have made no mistake +in the selection of your trees. The purposes for which you intend your +fruit is highly important. You should well consider at the outset if +for family or market use. This is a business which requires a long look +ahead, for it is said, "He who plants pears looks ahead for his heirs." + +Caution should be used in procuring your stock; little should be planted +that is not fairly tested on the Island, purchased of parties who can be +fully relied upon to give you what you want. Do not buy your stock of +parties who carry labels in their pockets to make to order what you want +out of the same bundle of trees. + +Now, having your trees set out in a proper manner, of such varieties +as you desire, the next important step is to bring the trees into +usefulness. My plan is to use bone--fine bone--very freely about every +three years. Another important matter is that of trimming. "Fire +purifies," and the knife regulates the grand balance or equilibrium +between roots and tops. In most cases the top outgrows the roots, the +consequence of which is an ultimate weakness of the tree. It is thrown +into excessive fruiting, disease, and premature decay. To avoid this +result, use the knife when required. Thin out the inside branches when +small, and if the tree does not make a satisfactory growth, cut back +half way to the ground. + +We will suppose that you have got your trees growing nicely, and they +have begun to bear fruit. There are other important steps to be taken, +which will be of little cost to you. Provide a wind-break for the +orchard. Evergreens answer the purpose, being a protection against the +wind. Having this matter attended to, there are other enemies with which +we must contend. I refer to the apple and peach tree borers. The former +will live in the tree for three years, if unmolested; the latter, one +year only. They are very easily destroyed by looking over the trees and +taking them out with a knife; or maybe prevented from touching the trees +by wrapping a piece of felt paper, 8 inches wide, around the tree near +the ground, the bottom being covered with dirt and the top tied tightly +above. The pear is not generally disturbed by these insects--only the +apple, peach, and quince. We have another insect very destructive to the +plum, peach, cherry, and apple--the _curcutio_, or plum weavel. This +season for the first time in twenty years we have gathered a small +crop of that very desirable plum, the Purple Favorite. We simply threw +air-slaked lime over the trees nearly every morning for from four to six +weeks, from the time the tree was out of bloom. Peach trees should be +treated in the same manner. Another method of fighting this insect is to +spread a sheet under the tree, and with a blow jar off the little Turk +and secure him on the sheet. But I consider the lime procedure the less +trouble and more effective. The tent caterpillar, which is easily seen, +should be destroyed at once. We have yet another insect to contend with +which infests the apple and pear, commonly called the Coddling Moth, +and the larva, the apple-worm (_Garpocapsa pomonella_). The loss by the +ravaaes of this insect alone to the fruit growers of the United States +fan hardly be estimated, as in many cases the whole crop is rendered +worthless. Such a vast destruction of two of the most valuable fruits +the world produces should stimulate scientists in this age of progress +to discover an effectual remedy against such a gigantic evil. + +I have never yet discovered nor tried an effectual remedy against this +insect. The nearest I have approached his extermination is in the +following manner: After it has entered the fruit and accomplished its +damage, the time arrives when it has to leave the fruit and hide itself +in a quiet, secure position to undergo the transition from the larva to +the pupa state, which requires, in the early part of the season, eight +or ten days; after this time the miller is hatched and is again ready to +besiege the fruit with its sting. The insect, being two-brooded in this +climate at least, if not disturbed, has an aggregating force to do +mischief the second time. The progeny for the succeeding year have alone +to depend on the security of this second generation of larvæ. As they +may often be found in bark of apple trees during winter, my plan of +destruction is, about the first of July to take woolen rags long enough +to wrap around the trees, and say four inches wide. Each week I look +over the trees, and destroy the worms secreted under the rags and +wherever I find them until the fruit is off the trees. I have all the +green fruit, of every kind, carefully picked up as soon as it falls, +thereby destroying many of the curculio as well as the apple-worms. + +One word upon the grape--the insect part of the question. The +_Phylloxera vastatrix_, or grape-vine louse, is already at work on Long +Island. It is found very difficult to raise many of our fine, new grapes +with us in consequence of the depredations of this very minute insect, +it being almost too small to be seen by the naked eye. There has lately +been discovered a remedy which is entirely chemical and as yet but +little disseminated. Very soon, no doubt, a discovery will be made that +will stay the progress of this destructive enemy. + +We should plant aplenty of cherry and small fruit trees to yield feed +for birds. In return they will assist us in our efforts to preserve a +bountiful supply of this health producing element. + + * * * * * + + + + +COARSE FOOD FOR PIGS. + + +A recent subscriber wants advice how to feed pigs of 25 to 35 pounds +weight, that are to be kept over winter and fitted for sale at about six +months old--whether coarse food will not help them as much in winter as +in summer. How roots and pumpkins will answer in lieu of grass, and what +can be fed when this green food is gone? He has had poor success in +growing young pigs on corn alone. He has a reasonably warm pen for +winter. + +The question of food is constantly recurring, and this is one of the +best evidences of the advancement of the country in the feeder's +art. When people are making no inquiry as to improved methods in any +direction, no progress can be made. There has been more progress made +in the philosophy of feeding during the last thirty years than in the +century and a half previous. + +In pig feeding in the dairy districts, young pigs generally grow up in +a very healthy condition, owing to the refuse milk of the dairy, which +furnishes the principal food of young pigs. Skim-milk contains all the +elements for growing the muscles and bones of young pigs. This gave them +a good, rangy frame, and, when desired, could be fed into 400 or 500 +pounds weight. But the fault attending this feeding was, that it was too +scanty to produce such rapid growth as is desired. It took too long to +develop them for the best profit. It had not then been discovered by the +farmer that it costs less to put the first hundred pounds on the pig +than the second, and less for the second than the third, etc.; that it +was much cheaper to produce 200 pounds of pork in six months than in +nine and twelve months. When it became evident that profit required more +rapid feeding, then they began to ply them continually with the most +concentrated food--corn meal or clear corn. If this was fed in summer, +on pasture, no harm was observed, for the grass gave bulk in the +stomach, and the pigs were were healthy and made good progress. But if +the young pigs were fed in pen in winter upon corn meal or clear corn, +the result was quite different; this concentrated food produced feverish +symptoms, and the pigs would lose their appetite for a few days, +drinking only water, which, after a while, would relieve the stomach, +and the pigs would eat vigorously again. Now, had they been fed a few +quarts of turnips, carrots, beets, or pumpkins, to give bulk to the +stomach, and separate the concentrated food, no harm would have come. +This gives the gastric juice a free circulation through the contents of +the stomach, the food is properly digested and applied to the needs of +the body instead of causing fever by remaining in the stomach.--_Live +Stock Journal_. + + * * * * * + + + + +METE KINGI. + + +Our engraving is a portrait of a familiar character in New Zealand, +chief Mete Kingi, who recently died at the age of one hundred years. +He was a fine specimen of the Maori race, the native New Zealanders, a +branch of the Malayo-Polynesian family. The New Zealanders surpassed +all other people in the art of tattooing, to which their chiefs gave +especial attention. Mete Kingi, as our picture shows, was no exception. +Tattooing on the face they termed _moko_. The men tattoo their faces, +hips, and thighs; the women their upper lips; for this purpose charcoal +made from kauri gum is chiefly used. It has the blue color when pricked +into the skin, growing lighter in shade in the course of years. The +subject of our illustration embraced Christianity, and was much +respected. Our engraving is from the _Illustrated Australian News_. + +[Illustration: THE LATE MAORI CHIEF METE KINGI.] + + * * * * * + + + + +LAKE TAHOE. + + +Some very interesting information by Prof. John Le Conte, is given in +the _Overland Monthly_, being the result of some physical observations +made by the author at Lake Tahoe, in 1873. Lake Tahoe, also called Lake +Bigler, is situated at an altitude of 6,247 feet in the Sierra Nevada +Mountains, partly in California, partly in Nevada. The lake has a length +of 22 and a width of 12 miles. As regards its origin, the author regards +it as a "plication hollow," or a trough produced by the formation of two +mountain ridges, afterward modified by glacial agency. The depth of the +lake is remarkable; the observations taken at ten stations along the +length of the lake gave the following depths in feet: 900, 1,385, 1,495, +1,500, 1,506, 1,540, 1,504, 1,600, 1,640, 1645. This depth exceeds that +of the Swiss lakes proper--Lake Geneva, for example, has a maximum depth +of 1,096 feet--but is considerably less than that of Lakes Maggiore and +Como, on the Italian side of the Alps. A series of observations of the +temperature of the water were taken between the 11th and 18th of August. +The average corrected results are as follows: + + Depth in feet. Temp. (C.) + 0(surface).................................19.4 + 50..........................................17.2 + 100..........................................12.8 + 150..........................................10.0 + 200.......................................... 8.9 + 250.......................................... 8.3 + 300.......................................... 7.8 + 330 (bottom)................................. 7.5 + 400.......................................... 7.2 + 480 (bottom)................................. 6.9 + 500.......................................... 6.7 + 600.......................................... 6.1 + 772 (bottom)................................. 5.0 + 1506 (bottom)..............,.................. 4.0 + +The temperature, therefore, diminishes with increasing depth to about +700 or 800 feet, and below this remains sensibly the same down to 1,506 +feet; or in other words, a constant temperature of 4° C. prevails at all +depths below about. 820 feet. This is in accordance with the theory, the +temperature named being that of the maximum density of water, and it +confirms the recent observations of Prof. Forel in Switzerland; he +found, for example, that a constant temperature of 4° C. was reached in +Lake Zurich at a depth of nearly 400 feet, the lake being then covered +with 4 inches of ice. The explanation of the observed fact that Lake +Tahoe does not entirely freeze over even in severe winters is found in +the extreme depth; and the fact that the bodies of drowned persons do +not rise to the surface after the lapse of the usual time is explained +by the low temperature prevailing near the bottom, which does not allow +the necessary decomposition to go forward so as to produce the ordinary +result. + +The water of Lake Tahoe is remarkable both for its transparency and +beauty of color. A series of observations made at the close of August or +beginning of September showed that a horizontally adjusted dinner plate +of about 9½ inches diameter was visible at noon at a depth of 108 feet. +The maximum depth of the limit of visibility as found by Prof. Forel, in +Lake Geneva, was 56 feet. He showed, moreover, that this limit is much +greater in. winter than in summer, as explained in part by the greater +absence of suspended matter and in part by the fact that increase of +temperature increases the absorbing power of water for light. The +maximum depth of visibility in the Atlantic Ocean, as found by Count +de Pourtales, was 162 feet, and Prof. Le Conte states his belief that +winter observations in Lake Tahoe would place the limit at even a +greater depth than this. The author gives a detailed and interesting +discussion in regard to the blue color of lake waters, reviewing in full +the results of previous writers on the subject, and concludes that while +pure water unquestionably absorbs a larger part of the red end of the +spectrum, and hence appears blue by transmitted light, the color seen by +diffuse reflection is mainly due to the selective reflection from the +fine particles suspended in it. + +The last subject discussed by the author is that of the rhythmical +variations of level, or "seiches," of deep lakes; he applies the usual +formula to Lake Tahoe, and calculates from it the length of a complete +longitudinal and of a transverse "seiche;" these are found to be +eighteen or nineteen minutes in the first case and thirteen minutes in +the second. + + * * * * * + +A catalogue, containing brief notices of many important scientific +papers heretofore published in the SUPPLEMENT, may be had gratis at this +office. + + * * * * * + + + + +THE SCIENTIFIC AMERICAN SUPPLEMENT. + +PUBLISHED WEEKLY. + +TERMS OF SUBSCRIPTION, $5 A YEAR. + + +Sent by mail, postage prepaid, to subscribers in any part of the United +States or Canada. 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