Scientific American Supplement, No. 433, April 19, 1884

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

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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.

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