Chapter 1

Produced by J. Niehof, D. Kretz, J. Sutherland, and Distributed Proofreaders

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.

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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.

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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.

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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.

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_.

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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.