Scientific American Supplement, No. 447, July 26, 1884

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The by-products obtained in the manufacture of coal gas, the tar and the
ammonia water, are nowadays scarcely less important than the coal gas
itself. The ammonia water furnishes large quantities of salts to be
used, among other applications, as food for plants. We thus restore
to-day to our vegetation the nitrogen which existed in plants of
primeval times. The tar, black and noisome though it be, is a marvelous
product, by the reason of scores of beautiful substances which are
concealed within it.

Coal tar when distilled yields three main products: naphtha, dead oil,
and pitch or asphalt. The naphtha on redistillation yields benzine, from
which are prepared some of our most beautiful dyes; the dead oil, as
the less volatile portion is termed, furnishes carbolic acid, used as a
disinfectant and antiseptic, together with anthracene and naphthaline;
all three substances the starting points of new series of coloring
matters.

This discovery of these coloring matters marks an era in the history
of chemical science; it exercised an extraordinary influence on the
development of organic chemistry. Theoretical and applied chemistry were
knit together in closer union than ever, and dye followed dye in quick
succession; after mauve came magenta, and in close attendance followed a
brilliant train of reds, yellows, oranges, greens, blues, and violets;
in fact, all the simple and beautiful colors of the rainbow.

But there is still another story of coal tar to be told. Among the
many curious substances that wonderful fluid contains is the beautiful
wax-like body called paraffine, the development of which chiefly owes
its origin to the genius and energy of Mr. James Young. As early as
1848, Mr. Young had worked a small petroleum spring in a coal mine in
Derbyshire, and had produced oils suitable for burning and lubricating
purposes, but the spring gave out, and then Mr. Young sought to obtain
these oils by distilling coal. After many trials, in conjunction with
other gentlemen connected therewith, he proved successful, and the
present magnitude of this industry is without parallel in the history of
British manufactures.

In Scotland alone there are about sixty paraffine oil works, one alone
occupying a site of nearly forty acres. Here about 120,000 gallons of
crude oil are produced weekly, and among the various works in Scotland
about 800,000 tons of shale are distilled per annum, producing nearly
30,000,000 gallons of crude oil, from which about 12,000,000 gallons of
refined burning oil are obtained in addition to the large quantities
of naphtha, solid paraffine, ammonia, and other chemical products.
Twenty-five years ago scarcely a dozen persons had seen this paraffine,
and now it is turned out by the ton, fashioned into candles delicately
tinted with colors obtained from coal tar.

I might dwell on this subject until it becomes wearisome to you,
therefore I will not trespass too much on your time. But from every
point we look we reach this fact, that our coal trade is one which
develops itself according to laws that we are perfectly powerless to
control; if it seems to promise a less rapid increase here, it is only
that it may spread abroad with accelerated vigor elsewhere; if it is our
slave in some aspects, it seems as if it were our master in others.

Finally, we have to ask, What of our export coals? Rapid as has been the
growth of our total production during the last twenty-three years, the
growth of our export of coals has been greater still. Beginning at
4,300,000 tons in '54, we find it reaching 16,250,000 tons in '76, and
an increase at a corresponding ratio up to the present date as far as
statistics will carry us. At such a rate of increase it would seem as
if our whole annual production would be ultimately swallowed up in our
exports, and it is not, perhaps, impossible that after we have ceased to
be to any great extent a manufacturing people, a certain export trade
in coal may still continue. Just the same as the export trade in coal
preceded by centuries our own uses for it other than domestic, so may
it also survive these by a period as prolonged. If our descent from
our present favored position be a gradual one, much may be done in the
interval to adapt ourselves to the future outcome, but it is certain
that nothing will be done except under the stern persuasion of
necessity.

When our coal fields become exhausted, be it soon or late, he would be
a wise or, perhaps, a rash speculator who fixed himself to a year or a
generation. Being inevitable, the best philosophy is to make our decline
more gradual and less bitter. Sentimental regrets that these hills and
valleys will no longer resound with the din of labor, or be blackened by
the smoke of the factory, would surely be out of place. What we might
regret is that Britain, which we know and are proud of, the Britain
of great achievements in politics and literature, of free thought and
self-respecting obedience, of a thousand years of high endeavor and
constant progress, was indeed to perish when these factories and
furnaces whirled and blazed their last. But, it is not so. This
country's fortunes are gradually being merged into those of a Greater
Britain, which largely, through the aid of coal, whose prospective
loss we are lamenting, has grown beyond the limits of these islands to
overspread the vastest and richest regions of the earth; and we have no
reason to fear that the great inheritance that America and Australia
and New Zealand have accepted from us will in their hands be dealt
unworthily with in the future.

* * * * *

GASTON PLANTE.

This eminent scientist was born in Orthez (Department of
Basses-Pyrenees) on the 22d of April, 1834; at present in his fiftieth
year. He began his scientific career as assistant to Edmund Becquerel at
the Conservatoire des Arts et Metiers at Paris. In the year 1859, after
resigning his position at the above named institution, he entered upon
his researches in electricity, and has continued them ever since.
His work entitled "Recherches sur l'Electricite" is a model of clear
language and elegant demonstration, and contains all the papers
presented by Plante to the Paris Academy of Sciences since 1859.

[Illustration: GASTON PLANTE.]

At the Paris Electrical Exhibition in 1881, Plante received a Diploma
of Honor, the highest distinction conferred, while in the same year the
Academy of Sciences voted him the "Lacaze" prize, and the Society for
the Encouragement of National Industry presented him with the "Ampere"
medal, its highest award.

Plante deserves not only the honors conferred upon him by his own
country, but those of the world on account of his cosmopolitan
character--a rarity among his countrymen. He sends his apparatus to all
exhibitions of any consequence; they appeared at Munich and Vienna,
where their interpretation by the attendant added considerably to the
renown of their author.--_Zeitch f. Elektrotechnik_.

* * * * *

WARREN COLBURN.

Warren Colburn, the eminent American mathematician, was born in Dedham,
Mass., March 1, 1793.

He was the eldest son of a large family of children. His parents were
poor, and "Warren" was, during his childhood, frequently employed in
different manufacturing establishments to aid the family by his small
earnings.

In early boyhood he manifested an unusual taste for mathematics, and
in the common district school was regarded as remarkable in this
department. He learned the trade of a machinist, studying winters, until
he was over twenty-two years of age, when he began to fit for Harvard
College, which he entered in 1817 and graduated with high honors in
1820. He taught school in the winter months, while in college, in
Boston, Leominster, and in Canton, Mass. From 1820 to 1823 he taught a
select school in Boston.

While in college he was regarded as by far the best mathematician in his
class, and during this period thought there was the necessity for such a
book as his "First Lessons in Intellectual Arithmetic." This conviction
had been forced upon his mind by his experience in teaching. In the
autumn of 1821 he published his "first edition." His plan was well
digested, although he was accustomed to say that "the pupils who were
under his tuition made his arithmetic for him;" that the questions they
asked and the necessary answers and explanations which he gave in reply
were embodied in the book, which has had a sale unprecedented for
any book on elementary arithmetic in the world, having reached over
2,000,000 copies in this country, and the sale still continues, both in
this country and in Great Britain. It has been translated into most of
the European languages and by missionaries into many Asiatic languages.

After teaching in Boston about two and one-half years, he was chosen
superintendent of the Boston Manufacturing Company's works at Waltham,
Mass., and accepted the position; and in August, 1824, owing to the
mechanical genius he displayed in applying power to machinery, combined
with his great administrative ability, he was appointed superintendent
of the Lowell Merrimac Manufacturing Co., at Lowell, Mass. Here he
projected a system of lectures of an instructive character, presenting
commerce and useful subjects in such a way as to gain attention and
enlighten the people.

For several years he delivered gratuitous lectures on the Natural
History of Animals, Light, Electricity, the Seasons, Hydraulics,
Eclipses, etc. His knowledge of machinery enabled him admirably to
illustrate these lectures by models of his own construction; and his
successful experiments and simple teaching added much to the practical
knowledge of his operatives.

He proposed to occupy the space between the common schools and the
college halls by carrying, so far as might be practicable, the design of
the Rumford Lectures of Harvard into the community of the actual workers
of common life.

In the mean time he discharged his official duties efficiently, and the
superintendence of the schools of Lowell was also added to his labors.
He never relinquished, during these busy years, the design formed in his
college days of furnishing to the children of the country a series of
text-books on the _inductive plan_ in mathematics.

His "Algebra upon the Inductive Method of Instruction," appeared in
1825, and his "Sequel to Intellectual Arithmetic" in 1836. He regarded
the "Sequel" as a book of more merit and importance than the "First
Lessons."

He also published a series of selections from Miss Edgeworth's stories,
in a suitable form for reading exercises for the younger classes of
the Lowell schools, in the use of which the teachers were carefully
instructed.

In May, 1827, he was elected a Fellow of the American Academy of
Sciences. For several years he was a member of the Examining Committee
for Mathematics at Harvard College.

He was a member of the Superintending School Committee of Lowell; and so
busy were he and his coworkers that they were repeatedly obliged to hold
their meetings at six o'clock in the morning.

Warren Colburn was ardently admired--almost revered--by the teachers who
were trained to use his "Inductive Methods of Instruction" in teaching
elementary mathematics.

In personal appearance Mr. Colburn was decidedly pleasing. His height
was five feet ten, and his figure was well proportioned. His face
was one not to be forgotten; it indicated sweetness of disposition,
benevolence, intelligence, and refinement. His mental operations were
not rapid, and it was only by great patience and long continued thought
that he achieved his objects. He was not fluent in conversation; his
hesitancy of speech, however, was not so great when with friends as
with strangers. The tendency of his mind was toward the practical in
knowledge; his study was to simplify science, and to make it accessible
to common minds.

Mr. Colburn will live in educational history as the author of "Warren
Colburn's First Lessons," one of the very best books ever written, and
which, for a quarter of a century, was in almost universal use as a
text-book in the best common schools, not only in the primary and
intermediate grades, but also in the grammar school classes.

In accordance with the method of this famous book, the pupils were
taught in a natural way, a knowledge of the fundamental principles of
arithmetic. By its use they developed the ability to solve mentally and
with great facility all of the simple questions likely to occur in the
every day business of common life.

Undoubtedly Pestalozzi first conceived the idea of the true "inductive
method" of teaching numbers; but it was Mr. Colburn who adapted it to
the needs of the children of the common elementary schools. It has
wrought a great change in teaching, and placed Warren Colburn on the
roll as one of the educational benefactors of his age.

He died at Lowell, Mass., Sept. 13, 1883, at the age of 90
years.--_Journal of Education_.

* * * * *

THURY'S DYNAMO-ELECTRIC MACHINE.

Thury's dynamo-electric machine, which presents some peculiarities,
has never to our knowledge been employed outside of Sweden and a few
neighboring regions; but this is doubtless due to some personal motive
or other of its constructors, since it has, it would seem, given
excellent results in every application that has been made of it. It is
represented in perspective in Fig. 1, and in longitudinal section and
elevation in Figs. 2 and 3.

As may be seen, it is a multipolar (6-pole) machine in which an attempt
has been made to utilize magnetically, as far as possible, all the iron
used in the frame. For this reason the system has been given the form of
a hexagonal prism, whose faces are formed of flat electro-magnets, A, A,
xxx, constituting the inductors.

The internal angles of this prism are filled by polar expansions, P, P,
xxx, alternately north and south, that thus form in the interior of the
apparatus an inscribed cylinder designed to receive the armature. This
latter belongs to the kinds that are wound upon a cylinder in which the
wire is external thereto.

The conductors are placed upon the iron drum longitudinally and parallel
with its axis. But instead of being connected with each other at the
posterier end of the armature, as in the Siemens system, they are
connected according to chords that correspond to a fourth, a sixth,
or any equal fraction whatever of the circumference. Fig. 4 gives a
perspective view of the cylinder, upon which the conductors 1, 2, 3,
4, and so on, are placed according to generatrices. The armature is
supposed to be divided into six parts, each conductor passing over the
bases of the drum through a chord equal to the radius, that is to say,
corresponding to a sixth of the circumference.

Three conductors are all connected together in such a way as to form
but a single circuit closed upon itself. Conductor 1, for example, is
connected with No. 6 in such a way that the end issuing from 1 becomes
the end that enters No. 6. Conductor No. 3 is connected in the same way
with No. 8, and so on, up to the last conductor, which is connected in
its turn with the end that enters the first.

As the figure shows, the conductor before passing from 3 to 8, for
example, returns several times upon itself in following 6 and 3, and the
same is the case with all the rest of the winding.

[Illustration: FIG. 1. PERSPECTIVE VIEW OF THE THURY MACHINE.]

In this way the cylinder becomes inclosed within nine rectangular wire
frames, each of which is connected with the following one by a conductor
that is at the same time connected with one of the nine plates of
the collector. The number of the rubbers corresponds to that of the
inducting poles. They may be coupled in different ways, but they are in
most cases united for quantity.

It will be seen that the Thury armature resembles, in the system of
winding, those of the Siemens machines and their derivatives. But it
differs from these, however, in the details connected with the coupling
of the wires, from the very fact that the features of a two-pole machine
are not found exactly in a multipolar one.

[Illustration: FIGS. 2 AND 3.]

This latter kind of machine is considered advantageous by its inventors,
in that there is no need of revolving it with much velocity. It must not
be forgotten, however, that although we reduce the velocity by this mode
of construction, we are, on another hand, obliged to increase the size
of the machine, so that, according to the circumstances under which we
chanced to be placed, the advantage may now be on the one side and now
on the other.

[Illustration: FIGS. 4 AND 5.]

It goes without saying that Fig. 4 is essentially diagrammatic, and is
designed to give a clearer idea of the mode of winding the armature. In
practice the number of the frames, and consequently that of the plates
of the conductor, is much greater, and the arrangement that we have
described is repeated a certain number of times, the conducter always
forming a circuit that is closed upon itself.

The Thury machines are constructed in different styles. No. 1 is a
100-lamp (16 candles and 100 volts) machine, and Nos. 2 and 3 are
nominally 250-lamp ones, but may be more. Their weight is 1,100
kilogrammes, and their velocity, for 100 volts, is from 400 to 500
revolutions, according to the mode of coupling.

A later type, now in course of construction, is to furnish from 750 to
2,000 lamps, with 250 revolutions, for 100 volts, and is not to weigh
more than 2,000 kilogrammes. Let us add that Messrs. Meuron and Cuenod,
the manufacturers, have likewise applied their mode of winding to
conductors arranged radially upon the surface of a circle. Fig. 5 shows
this arrangement.

In this case the inductors will, it is unnecessary to say, be arranged
laterally as in all flat ring machines. The arrangement will recall, for
example, that of the Victoria machines (Brush-Mordey).

We do not think that the inventors have applied this radial arrangement
practically, for it does not appear to be advantageous. The parts of
conductors which are perpendicular to the radius, and which can be only
inert (even if they do not become the seat of disadvantageous currents),
have, in fact, too great an importance with respect to the radial
parts.--_A. Guerout, in La Lumiere Electrique_.

* * * * *

BREGUET'S TELEPHONE.

Prof. G. Forbes gives the following description: The instrument which
I call Breguet's telephone is founded upon the instrument which was
described by Lipmann, called the capillary electrometer. The phenomenon
may be shown in a variety of ways. One of the easiest methods to show it
is by taking a long glass tube and bending it into two glasses of dilute
acid, and, the tube being filled with acid itself, a piece of mercury
is placed in the center of the tube. Then if one pole of a battery is
connected with one vessel of acid, and the other pole of the battery is
connected with the other vessel of acid, at the moment of connection the
bit of mercury will be seen to travel to the right or left, according to
the direction of the current. M. Lipmann explained the action by showing
that the electro-motive force which is generated tends to alter the
convexity of the surface of the mercury. The surface of the mercury,
looked at from one side, has a convex form, which is altered by the
electro-motive force set up when connection is made with the battery.
The equilibrium of the mercury is dependent upon the convexity, and
consequently when the convexity is disturbed the mercury moves to one
side or the other. Lipmann also showed that if a tube containing a bit
of mercury, and tapering to a point, is taken and dipped into acid, and
then the tube filled with acid, on one pole of a battery being dipped
into the tube and another into the acid the mercury will move up or
down, showing similar action to that which I have just described.

Lipmann further showed the reverse effect, that if a piece of mercury be
forcibly pressed, so as to alter the convexity of its surface, such
as by bringing it into a narrower part of the tube, then there is an
electro-motive force produced.

It occurred to me, and no doubt it did to Breguet also, that if we speak
either against the surface of the glass tube, and caused the tube to
vibrate, or if the mercury were caused to vibrate in the manner I have
shown, we ought to be able to introduce a varying current in the wires
which might have sufficient electro-motive force to produce audible
speech in a Bell telephone. Further, the same instrument, since varying
electro-motive force affected the drop of mercury and produced varying
displacement, ought also to act as a receiving instrument, and should
vibrate in accordance with the currents that arrive. My experiments
have only been in the way of using the instrument as a transmitter; but
Breguet, I find, used it as a receiver as well as a transmitter, though
I am not aware that M. Breguet made any actual experiments so as to
produce articulate speech. I presume that this was done, although I have
not come across any description of the experiments, and it was for that
reason that I thought possibly some account of my own experiments might
be interesting to the members of the Society. The first tubes that I
used were bits of glass tube about a centimeter diameter, and simply
drawn out to a tapering point. I have the tubes here. The first
experiment I tried was by tapping the glass tube so as to mechanically
shift the position of the mercury, and by listening on the telephone for
the effect. For a long time, at least an hour, I could get no effect at
all. At last I got a sound, but could not understand how it was that at
one time of tapping I could not hear, while at another time it was quite
loud.

At the top I always got sound, but at the side I got no sound, although
the mercury was shaking. I then tried to see how feeble a current was
audible in the telephone. An assistant tapped the tube while I stood out
of the way, and where I could not see. I got him to tap it gentler and
gentler, and could hear the most feeble tap. A pellet of paper was next
dropped from various heights down to an inch, and each tap was perfectly
audible in the telephone. I tried many methods, and one, purely
accidentally chosen, was a piece of glass tube which I had drawn out
into a tube about 2 mm. diameter, and then nearly closed the end of
it. I have that tube here, and you will see what an ill-shapen and
ugly-looking tube it is, but it is one of the best tubes I ever got; and
finally, I found that small bits of thermometer tube, which were simply
closed at their ends with a blow-pipe, gave very good results, and I was
able to make them useful for various purposes. I then tried mounting a
tube on the end of a speaking-trumpet and speaking to the mercury, but
got no effect. In every place where I attached the glass tube itself
to a sounding-board I got a very accurate reproduction. I put one on a
piece of ferrotype plate, and that gave really the best result I ever
got. The tube was fastened with sealing-wax, and with it I got excellent
speech heard in a Bell receiver. I tried putting in a large number of
these tubes, all in quantity, on the bottom of a ferrotype plate, but
with no advantage. I have not yet tried putting them in series, one
behind the other, so as to increase the electro-motive force, but I
think that probably would be an improvement; of course it would require
many vessels of acidulated water to dip into. The most distinct
articulate speech was obtained from an ordinary ferrotype telephone
plate, secured at the edges, and one of the glass tubes you see here
attached to it.

* * * * *

MUNRO'S TELEPHONIC EXPERIMENTS.

Mr. J. Munro, whose name is well known not only as a very clear writer
upon electrical subjects, but as an original investigator, has recently,
with the assistance of Mr. Benjamin Warwick, been conducting a most
interesting experimental investigation of the action of the microphone
as a telephonic transmitter, with the result of proving that metals may
advantageously be employed in the place of carbon in a transmitting
instrument, a practical development of one of the very earliest of
Professor Hughes' microphones. The fact that metallic electrodes can
practically be employed in microphonic transmitters has been denied of
late with so much assurance and in such high quarters, that Mr. Munro's
successful applications of that portion of Professor Hughes' discovery
possess an especial interest, and must to a considerable extent affect
the aspect of litigation in future contests in which the discovery of
the microphone and the invention of the carbon transmitter are vital
points at issue.

In investigating the properties of metallic conductors employed in the
construction of microphones, Mr. Munro's first experiments were made
with wires. These, in some cases, were caused by the action of a
diaphragm, to rub the one on the other in such a manner as to make the
point of contact vary (under the influence of the vibrations of the
diaphragms) on one side or other of a position of normal potential, so
that by the movement of a wire attached to a vibrating tympan along a
fixed wire conveying a current from a battery, and thereby shunting the
current at various positions along the length of the fixed wire, the
strength of the current in the derived circuit, in which was included a
suitable receiver, was varied accordingly. In other experiments mercury
was employed, either as a sliding-drop, inclosing the fixed wire, or as
an oscillating column; but these experiments, though instructive and
interesting, did not for various reasons give encouraging results with a
view to the practical application of the principle.

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