times is the electrical transmission of power over comparatively great
distances. At some cheap source of energy, say, at a waterfall, a
water-wheel is employed to drive a dynamo or generator, thus converting
mechanical energy into electrical energy. This electricity is passed
over a conducting line to a distant station, where it is either directly
utilized for the purpose of lighting, heating, chemical decomposition,
etc., or indirectly utilized for the purpose of obtaining mechanical
power for driving machinery, by passing it through an electric motor.
The electric transmission of power has been successfully made in
California over a distance of some 220 miles, at a pressure on
transmission lines of 50,000 volts.
The high pressures required for the economical use of transmission lines
necessitates the employment of transformers at each end of the line;
namely, step-up transformers at the transmitting end, to raise the
voltage delivered by the generators, and step-down transformers, at the
receiving end, to lower it for use in the various translating devices.
These transformers are employed in connection with alternating-current
dynamos. Faraday not only gave to the world the first electric
generator, but also the first transformer, and one of the first electric
motors, and without these gifts the electric transmission of power over
long distances, which has justly been regarded as one of the most
marvellous achievements of our age, would have been an impossibility.
In high-tension circuits over which such pressures as 50,000 volts is
transmitted, no little difficulty is experienced from leakage and
consequent loss of energy. This leakage occurs both between the line
conductors and at the insulators placed on the pole lines forming the
line circuit. The insulators are made either of glass or porcelain, and
are of a peculiar form known as triple petticoat pattern. The loss on
such lines, due to leakage between wires, is greater than that which
takes place at the pole insulators, and is diminished by keeping the
circuit wires as far apart as possible.
In the early history of the art, electric transmission of power was
effected by means of direct-current generators and motors,--generators
and motors through which the current always passed in the same
direction. Such generators and motors, however, possessed inconveniences
that prevented extensive commercial transmission of power, since, as we
have seen, high pressure was necessary for efficiency in such
transmission, and the collecting-brushes and commutators employed in all
direct-current generators and motors to carry the current from the
machine or to the motor, were a constant source of trouble and danger.
When the alternating-current motor first same into general use, it was
employed, in connection with the alternating-current generator, in
electric transmission systems; but such motors also possess the
inconvenience of not readily starting from a state of rest, with their
full turning power, or torque, and of therefore being unsuitable where
the motor requires to be frequently stopped or started. Had these
difficulties remained unsolved, long-distance electric transmission of
power, so successful in operation to-day, and which bids fair to be
still more successful in the near future, would have been impossible.
Fortunately, these difficulties were overcome by the genius of Nikola
Tesla, in the invention of the multiphase alternating-current motor, or
the induction motor, as it is now generally called. Although Baily,
Deprez, and Ferraris had accomplished much before Tesla's time, yet it
was practically to the investigations and discoveries made by Tesla,
between 1887 and 1891, that the induction motor of to-day is due.
Another requirement of our twentieth-century civilization is rapid
transit, either urban or inter-urban, and this is afforded by various
systems of electric street railways or electric traction generally,
including electric locomotives and electric automobiles. The wonderful
growth in this direction which has been witnessed in the last few
decades would have been impossible without the electric generator and
motor, both gifts of Faraday to the world. Their application in this
direction must, therefore, go to swell the debt our civilization owes to
the labors of this great investigator.
In the system of electric street-car propulsion very generally employed
to-day, a single trolley wheel is employed for taking the driving
current from an overhead conductor, suspended above the street. The
trolley wheel is supported by a trolley pole, and is maintained in good
electric contact with the trolley wire, or overhead conductor. By this
means the current passes from the wire down the conductor connected with
the trolley pole, thence through the motors placed below the body of the
car, and from them, through the track or ground-return, back to the
power station. A small portion of the current is employed for lighting
the electric lamps in the car. In some systems an underground trolley
is employed.
An important device, called the series-parallel controller, is employed
in all systems of electric street-car propulsion. It consists of means
by which the starting and stopping of the car, and changes, both in its
speed and direction, are placed under the control of the motorman. A
separate controller is placed on both platforms of the car. The
series-parallel controller consists essentially of a switch by means of
which the several motors, that are employed in all street cars, can
be variously connected with each other, or with different electric
resistances, or can be successively cut out or introduced into the
circuit, so that the speed of the car can be regulated at will, as the
handle of the controller is moved by the motorman to the various notches
on the top of the controller box. As generally arranged, the speed
increases from the first notch or starting position to the last notch,
movements in the opposite direction changing connections in the opposite
order of succession, and, therefore, slowing the car. There is, however,
no definite speed corresponding to each notch, for this will vary with
the load on each car, and with the gradient upon which it may
be running.
But there is another valuable gift received by the world as a result of
this great discovery of Faraday; namely, that most marvellous instrument
of modern times, the speaking telephone. This instrument was invented in
1861, by Philip Ries, and subsequently independently reinvented in 1876,
by Elisha Gray and Alexander Graham Bell.
As is well known, it is electric currents and not sound-waves that are
transmitted over a telephone circuit. The magneto-electric telephone in
its simplest form consists of a pair of instruments called respectively
the transmitter and the receiver. We talk into the transmitter and
listen at the receiver. Both transmitter and receiver consist of a
permanent magnet of hardened steel around one end of which is placed a
coil of insulated wire. In front of this coil a diaphragm, or thin
plate, of soft iron, is so supported as to be capable of freely
vibrating towards and from the magnet pole.
The operation of the transmitting instrument is readily understood in
the light of Faraday's discovery. It is simply a dynamo-electric machine
driven by the voice of the speaker. As the sound-waves from the
speaker's voice strike against the diaphragm, which has become magnetic
from its nearness to the magnet pole, electric currents are generated in
the coil of wire surrounding such pole, since the to-and-fro motions
cause the lines of electro-magnetic force to pass through the wire on
the moving coil. The operation of the receiving instrument is also
readily understood. It acts as an electric motor driven by the
to-and-fro currents generated by the transmitter. As these currents are
transmitted over the wire, they pass through the coil of wire on the
receiving instrument, and reproduce therein the exact movements of the
transmitting diaphragm, since, as they strengthen or weaken the
magnetism of the pole, they cause similar motions in the diaphragm
placed before it. Consequently, one listening at the receiving diaphragm
will hear all that is uttered into the transmitting diaphragm. It was
thus, by the combination of the dynamo and motor, both of which were
given by Faraday to the world, that we have received this priceless
instrument, which has been so potent in its effects on the civilization
of the Twentieth century.
The electric telegraph had its beginnings long before Faraday's time. As
early as 1847, Watson had erected a line some two miles in length,
extending over the housetops in London, and operated it by means of
discharges from an ordinary frictional electric machine. In 1774, Lesage
had erected in Geneva an electric telegraph consisting of a number of
metallic wires, one for each letter of the alphabet. These wires were
carefully insulated from each other. When a message was to be sent over
this early telegraphic line an electric discharge was passed through the
particular wire representing the letter of the alphabet to be sent; this
discharge, reaching the other end, caused a pithball to be repelled and
thus laboriously, letter by letter, the message was transmitted. How
ludicrously cumbersome was such an instrument when contrasted with the
Morse electro-magnetic telegraph of to-day, which requires but a single
wire; or with the harmonic telegraph of Gray, which permits the
simultaneous transmission of eight or more separate messages over a
single wire; or with the wonderful quadruplex telegraphic system of
Edison which permits the simultaneous transmission of four separate and
distinct messages over a single wire, two in one direction, and two in
the opposite direction at the same time; or with the still more
wonderful multiplex telegraph of Delaney, which is able to
simultaneously transmit as many as seventy-two separate messages over a
single wire, thirty-six in one direction and thirty-six in the opposite
direction. These achievements have been possible only through the
researches and discoveries of Oersted, Faraday, and hosts of other
eminent workers; for, it was the electro-magnet, rendered possible by
Oersted, together with the magnificent discoveries of Faraday, and
others since his time, that these marvellous advances in
electro-telegraphic transmission of intelligence have become
possibilities.
Before completing this brief sketch of some of the effects that
Faraday's work has had on the practical arts and sciences, let us
briefly examine the generating plants that are either in operation or
construction at Niagara Falls.
Some idea of the size of the Niagara Falls generating plant on the
American side may be gained from the fact that there have already been
installed eleven of the separate 5,000 horse-power generators. The
remaining capacity of the tunnel will permit of the installation of
50,000 additional horse-power, or 105,000 horse-power in all.
On the Canadian side of the Falls another great plant is about to be
erected with an ultimate capacity of several hundred thousand
horse-power. Here, however, the size of the generating unit will be
double that on the American side, or 10,000 horse-power. These
generators will be wound to produce an electric pressure of 12,000
volts, raised by means of step-up transformers to 22,000, 40,000, and
60,000 volts, according to the distance of transmission. Each of the
revolving parts of these machines will weigh 141,000 pounds. To what
gigantic proportions has the little infant dynamo of Faraday grown in
this short time since its birth!
The low rates at which electric power can be sold in the immediate
neighborhood of the Niagara generating plant have naturally resulted in
an enormous growth of the electro-chemical industries, for these
industries could never otherwise develop into extended commercial
applications. Of the total output of, say, 55,000 horse-power at the
Niagara Falls generating plant, no less than 23,200 horse-power is used
in various electrolytic and electro-thermal processes in the immediate
neighborhood. Some of the more important consumers of the electric
power, named in the order of consumption, are for the manufacture of the
following products: calcium carbide, aluminium, caustic soda and
bleaching salt, carborundum, and graphite.
Calcium carbide, employed in the production of acetylene gas, either for
the purposes of artificial illumination, or for the manufacture of ethyl
alcohol, is produced by subjecting a mixture of carbon and lime to the
prolonged action of heat in an electric furnace.
Aluminium, the now well-known valuable metal, present in clay, bauxite,
and a variety of other mineral substances, is electrolytically deposited
from a bath of alumina obtained by dissolving bauxite either in
potassium fluoride or in cryolite. Aluminium is now coming into extended
use in the construction of long-distance electric power
transmission lines.
Caustic soda and bleaching salt are produced by the electrolytic
decomposition of brine (chloride of sodium). The chlorine liberated at
the anode is employed in the manufacture of bleaching-salt, and the
sodium is liberated at a mercury cathode, with which it at once enters
into combination as an alloy. On throwing this alloy into water the
sodium is liberated as caustic soda.
Carborundum, a silicide of carbon, is a valuable substance produced by
the action of the heat of an electric furnace on an intimate mixture of
carbon and sand. It has an extensive use as an abrasive for grinding and
polishing.
Artificial graphite is another product produced by the long-continued
action of the heat of the electric furnace on carbon under certain
conditions.
According to reports from the United States Geological Survey, the
graphite works at Niagara Falls produced in 1901, 2,500,000 lbs. of
artificial graphite, valued at $119,000. This was an increase from
860,270 lbs., valued at $69,860 for 1900, and from 162,382 lbs., valued
at $10,140, in 1897, the first year of its commercial production. In
1901, more than half of the output was in the form of graphitized
electrodes employed in the production of caustic soda and bleaching
salt, and in other electrolytic processes.
The Niagara Falls power transmission system stands to-day as a
magnificent testimonial to the genius of Faraday, and as a living
monument of the varied and valuable gifts his researches have bestowed
upon mankind. For here we have not only the dynamo, motors, and
transformers that he gave freely to the world, not only the
alternating-current transformer, and the system of transmission of
power, but we even find that the principal consumers of the enormous
electric power produced are employing it in carrying on some of the many
processes in electro-chemistry, a science that he had done so much
to advance.
Among some of the surprises electro-chemistry may have in store for the
world in the comparatively near future, may be a nearer approach to a
mastery of the laws which govern the combination of elementary
substances when under the influence of plant-life. If these laws ever
become so well known that man is able to form hi his laboratory the
various food products that are now formed naturally in plant organisms,
such a revolution would be wrought that the work of the agriculturist
would be largely transferred to the electro-chemist. Some little has
already been done in the direct formation of some vegetable substances,
such as camphor, the peculiar flavoring substance present in the vanilla
bean, and in many other substances. Should such discoveries ever reach
to the direct formation of some food staple, the wide-reaching
importance and significance of the discovery would be almost beyond
comprehension.
But, while the direct electro-synthetic formation of food products is
yet to be accomplished on a practical scale, the problem appears to be
nearing actual solution in an indirect manner. It has been known since
the time of Cavendish, in 1785, that small quantities of nitric acid
could be formed directly from the nitrogen and oxygen of the atmosphere
by the passage of electric sparks; but heretofore, the quantity so found
has been too small to be of any commercial value. Quite recently,
however, one of the electro-chemical companies at Niagara Falls has
succeeded in commercially solving the important problem of the fixation
of the nitrogen of the atmosphere; it being claimed that the cost of
thus producing one ton of commercial nitric acid, of a market value of
over eighty dollars, does not greatly exceed twenty dollars. Since
sodium nitrate can readily be produced by the process, and its value as
a fertilizer of wheat-fields is too well known to need comment, there
would thus, to a limited extent, be indirectly solved the
electro-chemical production of food staples.
Faraday's high rank as an investigator in the domain of natural science
was fully recognized by the learned societies of his time, by admission
into their fellowships. As early as 1824, he was honored by the Royal
Society of London by election as one of its Fellows, and in 1825 he had
become a member of the Royal Institution. It is recorded of the great
philosopher that the membership in the Royal Institution was the only
one which he personally sought; all others came unsought, but they came
so rapidly from all portions of the globe that in 1844 he was a member
of no less than seventy of the leading learned societies of the world.
Ries, the German electrician, so well known in connection with his
invention of the speaking telephone, addressed Faraday as "Professor
Michael Faraday, Member of all the Academies." Besides his membership in
the learned societies, Faraday received numerous degrees from the
colleges and universities of his time. Among some of these are the
following: The University of Prague, the degree of Ph.D.; Oxford, the
degree of D.C.L.; and Cambridge, the degree of LL.D. He also received
numerous medals of honor, and was offered the Presidency of the Royal
Society, which, however, he declined, as he did also a knighthood
proffered by the government of England. Faraday died on the 25th of
August, 1867, after a long, well-spent, useful life.
We have thus briefly traced some of the more important discoveries of
Michael Faraday. Many have necessarily been passed by, but what we have
given are more than sufficient to stamp him as a great philosopher and
investigator. Speaking of Faraday in this connection, Professor Tyndall
says: "Take him for all in all, I think it will be conceded that Michael
Faraday is the greatest experimental philosopher the world has ever
seen; and I will add the opinion that the progress of future research
will tend not to diminish or decrease, but to enhance and glorify, the
labors of this mighty investigator."
AUTHORITIES.
Experimental Researches in Electricity. By Michael Faraday. From the
Philosophical Transactions.
Abstracts of the Philosophical Transactions from 1800 to 1837.
Faraday's Experimental Researches in Electricity and Magnetism. 3 vols.
Life and Letters of Faraday. By Dr. Bence Jones.
Michael Faraday. By J.H. Gladstone.
Students' Text-Book of Electricity. By Henry M. Noad. Revised by W.H.
Preece.
Michael Faraday. By John Tyndall.
Pioneers of Electricity. By J. Munro.
Dynamo-Electric Machinery. By Silvanus P. Thompson.
A Dictionary of Electrical Words, Terms, and Phrases. By Edwin J.
Houston.
Electricity and Magnetism. By Edwin J. Houston.
Electricity One Hundred Years Ago and To-Day. By Edwin J. Houston.
Magnetism; Electro-Technical Series. By Edwin J. Houston and Arthur E.
Kennelly.
Electro-Dynamic Machinery. By Edwin J. Houston and A. E. Kennelly.
RUDOLF VIRCHOW.
1821-1902.
MEDICINE AND SURGERY.
BY FRANK P. FOSTER, M.D.
Stagnation was the state of medicine when the Nineteenth Century opened.
It was only three years before that Jenner had announced and
demonstrated the protective efficacy of vaccination against small-pox.
His teaching, in spite of the vehement cavillings of the "antis" of his
day, gained credence readily, and vaccination speedily became recognized
and was constantly resorted to, but hardly any attempt at perfecting the
practice was made until after more than fifty years had elapsed. His
discovery--or, rather, his proof of the truth of a rustic
tradition--fell like a pebble into the doldrums; the ripple soon
subsided, and nobody was encouraged to start another. At the present
time such an announcement would be promptly followed by investigations
leading up to such doctrines as that of the attenuation of viruses and
that of antitoxines. But the times were not ripe for anything of that
sort; medicine reposed on tradition, or at best gave itself only to such
plausibilities in the way of innovation as were cleverly advocated.
Physicians strove not to advance the healing art; as individuals, they
were content to rely on their manners, their tact, and their assumption
of wisdom. In short, the body medical was in a state of suspended
animation, possessed of a mere vegetative existence.
The Humoral pathology, or that doctrine of the nature of disease which
ascribed all ailments to excess, deficiency, or ill "concoction" of some
one of the four humors (yellow and black bile, blood, and phlegm), had
not yet lost its hold on men's convictions, or at least not further than
to make them look upon exposure to cold and errors of diet as amply
explanatory of all diseases not plainly infectious. The medical writers
who were most revered were those who busied themselves with nosology;
that is to say, the naming and classifying of diseases. Wonderful were
the onomatological feats performed by some of these men, and most
diverse and grotesque were the data on which they founded their
classifications. To label a disease was high art; to cure it was
something that Providence might or might not allow. In the treatment of
"sthenic" acute diseases (meaning those accompanied by excitement and
high fever), blood-letting, mercury given to the point of salivation,
antimony, and opium, together with starvation (all included under the
euphemism of "lowering measures"), were the means universally resorted
to and reputed "sheet anchors." Some advance had been made from the
times when disease had been looked upon as an entity to be exorcised,
but it was still so far regarded as a material thing that it was to be
starved out.