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[1] The general scheme of a fire-alarm telegraph system embodies
a central office to which notice can be sent from any number of
signal boxes of the outbreak of a fire in the district covered by
the box, the central office in turn calling out the nearest fire
engines, and warning the fire department in general of the
occurrence. Such fire alarms can be exchanged automatically, or
by operators, and are sometimes associated with a large fire-alarm
bell or whistle. Some boxes can be operated by the passing public;
others need special keys. The box mechanism is usually of
the ratchet, step-by-step movement, familiar in district messenger
call-boxes.
[2] This I invented as well.--T. A. E.
[3] See illustration on opposite page, showing reproduction of the
work done with this machine.
[4] The sand battery is now obsolete. In this type, the cell
containing the elements was filled with sand, which was kept moist
with an electrolyte.
[5] See Federal Reporter, vol. 109, p. 976 et seq.
[6] Briefly stated, the essential difference between Bell's
telephone and Edison's is this: With the former the sound vibrations
impinge upon a steel diaphragm arranged adjacent to the pole of
a bar electromagnet, whereby the diaphragm acts as an armature,
and by its vibrations induces very weak electric impulses
in the magnetic coil. These impulses, according to Bell's theory,
correspond in form to the sound-waves, and passing over the line
energize the magnet coil at the receiving end, and by varying the
magnetism cause the receiving diaphragm to be similarly vibrated
to reproduce the sounds. A single apparatus is therefore used at
each end, performing the double function of transmitter and receiver.
With Edison's telephone a closed circuit is used on which
is constantly flowing a battery current, and included in that circuit
is a pair of electrodes, one or both of which is of carbon.
These electrodes are always in contact with a certain initial
pressure, so that current will be always flowing over the circuit.
One of the electrodes is connected with the diaphragm on which
the sound-waves impinge, and the vibration of this diaphragm
causes the pressure between the electrodes to be correspondingly
varied, and thereby effects a variation in the current, resulting in
the production of impulses which actuate the receiving magnet.
In other words, with Bell's telephone the sound-waves themselves
generate the electric impulses, which are hence extremely
faint. With the Edison telephone, the sound-waves actuate an
electric valve, so to speak, and permit variations in a current of
any desired strength.
[7] As an illustration of the perplexing nature of expert evidence in
patent cases, the reader will probably be interested in perusing
the following extracts from the opinion of Judge Dayton, in the
suit of Bryce Bros. Co. vs. Seneca Glass Co., tried in the United
States Circuit Court, Northern District of West Virginia, reported
in The Federal Reporter, 140, page 161:
[8] As a practical illustration of these facts it was calculated by
Professor Barker, of the University of Pennsylvania (after Edison
had invented the incandescent lamp), that if it should cost $100,000
for copper conductors to supply current to Edison lamps in
a given area, it would cost about $200,000,000 for copper conductors
for lighting the same area by lamps of the earlier experimenters
--such, for instance, as the lamp invented by Konn in 1875. This
enormous difference would be accounted for by the fact that
Edison's lamp was one having a high resistance and relatively
small radiating surface, while Konn's lamp was one having a very
low resistance and large radiating surface.
[9] The following extract from Walker on Patents (4th edition)
will probably be of interest to the reader:
"Sec. 31a. A meritorious exception, to the rule of the last
section, is involved in the adjudicated validity of the Edison
incandescent-light patent. The carbon filament, which constitutes
the only new part of the combination of the second
claim of that patent, differs from the earlier carbon burners of
Sawyer and Man, only in having a diameter of one-sixty-fourth
of an inch or less, whereas the burners of Sawyer and Man had a
diameter of one-thirty-second of an inch or more. But that reduction
of one-half in diameter increased the resistance of the
burner FOURFOLD, and reduced its radiating surface TWOFOLD, and
thus increased eightfold, its ratio of resistance to radiating surface.
That eightfold increase of proportion enabled the resistance
of the conductor of electricity from the generator to
the burner to be increased eightfold, without any increase of
percentage of loss of energy in that conductor, or decrease of
percentage of development of heat in the burner; and thus enabled
the area of the cross-section of that conductor to be reduced
eightfold, and thus to be made with one-eighth of the amount of
copper or other metal, which would be required if the reduction
of diameter of the burner from one-thirty-second to one-sixty-
fourth of an inch had not been made. And that great reduction
in the size and cost of conductors, involved also a great difference
in the composition of the electric energy employed in the system;
that difference consisting in generating the necessary amount of
electrical energy with comparatively high electromotive force,
and comparatively low current, instead of contrariwise. For this
reason, the use of carbon filaments, one-sixty-fourth of an inch in
diameter or less, instead of carbon burners one-thirty-second of
an inch in diameter or more, not only worked an enormous economy
in conductors, but also necessitated a great change in generators,
and did both according to a philosophy, which Edison
was the first to know, and which is stated in this paragraph in its
simplest form and aspect, and which lies at the foundation of the
incandescent electric lighting of the world."
[10] For further explanation of "Feeder" patent, see Appendix.
[11] For description of feeder patent see Appendix.
[12] We quote the following interesting notes of Mr. Charles L.
Clarke on the question of see-sawing, or "hunting," as it was
afterward termed:
"In the Holborn Viaduct station the difficulty of `hunting'
was not experienced. At the time the `Jumbos' were first operated
in multiple arc, April 8, 1882, one machine was driven by
a Porter-Allen engine, and the other by an Armington & Sims engine,
and both machines were on a solid foundation. At the station
at Milan, Italy, the first `Jumbos' operated in multiple arc were
driven by Porter-Allen engines, and dash-pots were applied to the
governors. These machines were also upon a solid foundation,
and no trouble was experienced.
"At the Pearl Street station, however, the machines were sup-
ported upon long iron floor-beams, and at the high speed of 350
revolutions per minute, considerable vertical vibration was given
to the engines. And the writer is inclined to the opinion that
this vibration, acting in the same direction as the action of gravitation,
which was one of the two controlling forces in the operation
of the Porter-Allen governor, was the primary cause of the
`hunting.' In the Armington & Sims engine the controlling
forces in the operation of the governor were the centrifugal force
of revolving weights, and the opposing force of compressed springs,
and neither the action of gravitation nor the vertical vibrations
of the engine could have any sensible effect upon the governor,"
[13] For technical description and illustration of this invention,
see Appendix.
[14] By reason of the experience gained at this station through
the use of these crude plug-switches, Mr. Edison started a competition
among a few of his assistants to devise something better.
The result was the invention of a "breakdown" switch by Mr.
W. S. Andrews, which was accepted by Mr. Edison as the best of
the devices suggested, and was developed and used for a great
many years afterward.
[15] See 61 Fed. Rep. 655.
[16] For a proper understanding and full appreciation of the
importance of fine grinding, it may be explained that Portland
cement (as manufactured in the Lehigh Valley) is made from
what is commonly spoken of as "cement rock," with the addition
of sufficient limestone to give the necessary amount of lime.
The rock is broken down and then ground to a fineness of 80 to
90 per cent. through a 200-mesh screen. This ground material
passes through kilns and comes out in "clinker." This is ground
and that part of this finely ground clinker that will pass a 200-
mesh screen is cement; the residue is still clinker. These coarse
particles, or clinkers, absorb water very slowly, are practically
inert, and have very feeble cementing properties. The residue
on a 200-mesh screen is useless.
[17] Broadly described in outline, the system consisted of an induction
circuit obtained by laying strips of tin along the top or
roof of a railway car, and the installation of a special telegraph
line running parallel with the track and strung on poles of only
medium height. The train and also each signalling station were
equipped with regulation telegraphic apparatus, such as battery,
key, relay, and sounder, together with induction-coil and condenser.
In addition, there was a transmitting device in the shape of a
musical reed, or buzzer. In practice, this buzzer was continuously
operated at high speed by a battery. Its vibrations were broken
by means of a key into long and short periods, representing Morse
characters, which were transmitted inductively from the train
circuit to the pole line, or vice versa, and received by the operator
at the other end through a high-resistance telephone receiver
inserted in the secondary circuit of the induction-coil.
[18] Edison received some stock from the parent lighting company,
but as the capital stock of that company was increased from time
to time, his proportion grew smaller, and he ultimately used it to
obtain ready money with which to create and finance the various
"shops" in which were manufactured the various items of electric-
lighting apparatus necessary to exploit his system. Besides, he
was obliged to raise additional large sums of money from other
sources for this purpose. He thus became a manufacturer with
capital raised by himself, and the stock that he received later, on
the formation of the General Electric Company, was not for his
electric-light patents, but was in payment for his manufacturing
establishments, which had then grown to be of great commercial
importance.
[19] It may be of interest to the reader to note some parts of
the globe to which shipments of phonographs and records are made:
Samoan Islands [20] A most remarkable instance of contemporaneous invention
and without a parallel in the annals of the United States Patent
Office, occurred when, on the same day, February 15, 1876, two
separate descriptions were filed in that office, one a complete
application and the other a caveat, but each covering an invention
for "transmitting vocal sounds telegraphically." The application
was made by Alexander Graham Bell, of Salem, Massachusetts,
and the caveat by Elisha Gray, of Chicago, Illinois. On
examination of the two papers it was found that both of them
covered practically the same ground, hence, as only one patent
could be granted, it became necessary to ascertain the precise
hour at which the documents were respectively filed, and put the
parties in interference. This was done, with the result that the
patent was ultimately awarded to Bell.
Falkland Islands
Siam
Corea
Crete Island
Paraguay
Chile
Canary Islands
Egypt
British East Africa
Cape Colony
Portuguese East Africa
Liberia
Java
Straits Settlements
Madagascar
Fanning Islands
New Zealand
French Indo-China
Morocco
Ecuador
Brazil
Madeira
South Africa
Azores
Manchuria
Ceylon
Sierra
Leone
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