Scientific American Supplement, No. 433, April 19, 1884 by Various
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Various >> Scientific American Supplement, No. 433, April 19, 1884
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9 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.
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