Belmont chronicle. [volume] (St. Clairsville, Ohio) 1855-1973, 1879-05-29
The, Principles Of the Electro.
MOtOgraDn.

In the June Scribner, Mr.. Edwin NJ.
Fox describes the origin and develop
men of the eletro-motOgraph, Mr.. Edi-
sons most important invention, together
with some applications Of the principle
hitherto unannOunced. 1t must not be
forgotten that this invention, which now
transmits the human voice at distance
with perfect clearness and accuracy, is
not only an application of well-knOwn
laws of acoustics but involves the dis
cOvery by Mr.. Edison of an entirely un-
known property of electricity, viz, that
of destroying friction. OF the differences
between it and the phonograph, the writer
says:
The latest achievement of Mr.. Edison
is the electromagnetic, a brief explain
alton of which was made in the May
number Of this magazine. Although it
is yet in its infancy, the scope of its
utility has already become far more ex-
tensive than that of any of Mr.. Edison's
previous inventions. Probably its most
striking feature is its paradoxical power
of making the human hand talk; for the
hand revolves little cylinder, and the
instrument speaks as it is hidden, and
when the hand stops turning, the instru-
ment ceases to speak. At superficial
glance, this principle would seem to be
the same as that of the phonograph; but
in point of fact there is no essential SIM
ilarity between the two inventions; they
are used for entirely different purposes,
and are governed by separate and dis
tinct laws. The phonOgraph records
and preserves the waves of sound; the
eletro-mOtOgraph-or, as it is called
when used in connection with acoustics,
the chemical telephone - records
nothing. In the phOnOgraph the main
principle is the indentation of tin-fOil on
a cylinder, by small needle attached to
a diaphragm, which is set in motion by
the wave of sound. In the chemical
telephone there is likewise cylinder
and diaphragm; but with these its re-
semblance to the phonOgraph ceases.
On the cylinder of the chemical tele-
phone rests metal arm attached to a
diaphragm, and the passage of electric
waves through such cylinder causes the
vibration of the diaphragm, as will be
more fully explained farther on. The
scientific principle in the electrO-motO-
graph discovery is Numerically opposite
to the main principle in electromagnetic
ism, and yet it performs in most cases ex-
actly the same functions as electrO-mag-
netism.
In all cOntrivances hitherto used for
producing a mechanical movement at a
long distance, the agency employed has
been electromagnetic. Take for illus
tration the ordinary Morse telegraph.
This, as every school-boy knows, consists
in the rough of piece of soft iron
around which is coiled continuous fine
wire, through which wire is passed, so
to speak, current of electricity. This
current magnetizes the piece of soft iron,
which thereupon is enabled to attract a
second piece of iron or armature. Here,
then, we have a mechanical movement,
produced by energy transmitted from
distance. BY means of a discovery of
the principles of the electro-motOgraph,
Mr.. Edison has made it possible to pro-
duce mechanical movements at dis
tance without the employment of cleo
tro-magnetism. In other words, had the
inventor of the telegraph never lived,
and had electro-magnetism never been
discovered, we might to-day accomplish
the same results by means of the electro
photograph.