, 1877-08-11

'NN' ~ ''NN TNOH NN'AF'' " NlC NlNHNlIlo-
sion Of musical tones or sounds between
distant points by mrans rf electricity,
Aumber OF our most nuted inventors have
matle experiments to demonstrate what
could be done III that direction, aud
what 1t any, practical value such acous
'Ic telegrSphy possessed for the purposes
at ordinary commercial telrgmphy,
Among these inventors three have oh
Gained results Of interest to The scientist
and the public generally, They ure
Thomas A. Edison, OF Menlu Park, n. j.,
Elisha Gray "t Chicago, and W. A. Bell
of Boston. the ORIGINAL idea of each
was to devise system of multlplex
transmission 0t dispatches by means Of
the Morse appSratus in common use, the
modus opcranjI being to Use tuning
forks or other vibratory apparatus for
gene ating II number of tones. Placing
one instrument OF each tone ut the trans
uniting aud receiving station, then 10y
connecting these forks at the transmit.
ting station with IL battery, All impulse
or wave OF electricity was made to pass
from the battery over the intermediate
wire to the receiving instrument at each
vibration of such transmitting tnrk, the
forks 1T the receiving station being Uper-
ated hy means OF electromagnetic con.
trolled by the current passing over the
intermediate WIRE Each fork at the
transmitting station having its mate at
the receiving station. tuned 10 respond
tO the same number of vibrations per
second as that Al the transmitting station,
the vibration OF any fork OF given tone
would send over the wire and through
the electro magnets ut The receiving sta
sion such number of electric impulses az
would set in motion the particular fork
attuned in sympathy with that tone, or
Dumbsl Of vibrations, and although the
other magnets and their forks were in
circuit, they would not be affected, he.
cause the forks would only respond to
ahe number OF vibrations per second to
which they were attuned. A second
transmitting fork being set in motion
would start its counterpart at the recev-
ing station; . third also, and 80 0n to
Ie number o. eight BY tue alternate
starting and interrupting these tones, it
was aimed to transmit the ordinary
Morse signals, the operators ut the receiv,
ing station to read them by the eur, IS in
the common Morse sOunder. Each OF
the gentleman named succeeded to u Ger
tain extent in doing this, but all made it
fnanlly clear that in this direction com.
paratively triaing results OF value were
TO DO obtained. Hence, from this gen.
eral netion each di,erged into other paths
resulting finally, in the case OF Edison
and Bell--wilhout following them
through the labyrinth OF experiments
in the speaking telegraph, Or telephone,
whereby the human voice is transmitted
10 a distant station, and there reproduced
in an audible manner.
Astonishing as it may seem, it is never.
theless the fact that these two expert.
montcrs have obtained their results hy
widely different methods, Bell generates
his electricity by vibrating an iron dia.
phTasm placed close to the poles of a
powerful permanent magnet, and receives
the impulses thus simultaneously gener-
ated and transmitted upon similar dia.
phragm placed close to the poles of an
eIectro-nagnvt. This device is pecessa.
rlly very restricted in its capacity.
First, because of the small quantity of
the electricity possible to generate by
the power Of the human voice, thus lin
itlng the power OF the current to traverse
wire OF any considerable length.
Second, because of the use of an elec.
tFo-magnet for receiver. 1t being well
known that the element of time is an
important matter in the charging and
'iischarglng of an electro magnet, it will
be readily understood that the great
rapidity OF these electric charges overta1
ITS capacity. Hence, high notes are fire.
qnently lost or so reduced in volume "a
10 be scarcely audible
For these two reasons it will he seen
phnt Mr. Bells apparius is imitrd to
very short lines in its practical appliea.
'IOn.
Mr.. Edison, being a man or morkol