Year: 1877

operate? The answer is quite simple if
one will remember that there are two
instruments of the name, has seen the
toy known as the "lover's telegraph"
and is familiar with the operation of
ordinary telegraphic instruments.


Prof. Bells instrument for repeating
the minute shades of tone in converse
tion, dispenses with electricity alto
gether, and uses the wire to convey the
vibrations of sound just as the piece of
string in the "lovers telegraph" AL
though the apparatus at the endsis more
complicated than the little tin cups
covered with parchment, employed in
the toy above mentioned, the principle
is precisely the same. One talks against
sensitive membrane whose delicate
vibrations are impaired to the wire, and
are caught up and rendered audible by
a similar membrane on the receiving in
strument miles away. Every one knows
how the sound of an ordinary tuning
fork is made more audible by setting the
small end of the instrument on a table.
Just so sound that could not be heard
along the wire is brought out by the
exquisitely sensitive parchment of the
Bell telephone.


The instrument invented by Professor
Gray is designed to convey exact musi-
cal tones, singly or in chords, and works
on an entirely different plan, and re-
quires through current of electricity,
as in ordinary telegraphing.


The principle upon which the ordin-
ary telegraph depends is that the alter
nate closing and breaking of the electric
current by key, at the office of the
sender, magnetizes and demagnetizes
bit of soft iron about which the wire is
coiled at the Office of the receiver; the
changes in the conditions of this bit of
iron causes little lever to bob up and
down, making a click by which most
operators read the message, or recording
the intervals of its depressions and
risings by series of dots and dashes on
a slip of slowly moving paper. The
average operator sends thirty words
minute, averaging five letters word,
and four or five clicks or vibrations to
letter, or seven hundred and fifty breaks
and reunions of the electric current
minute. The waves of electricity that
pAss over the wire when the Gray tele-
phone is used vary in rate from forty to
five thousand asecond, but are neverthe-
less perfectly distinct from one another,
and never jumbled.


The sending instrument consists of a
keyboard like a piano, each key strik-
ing and causing to vibrate tiny bit
of steel called a reed, substantially the
same as the reed in musical instru-
ment. These reeds are of different sizes
and tuned to give out exact tones and
semi-tones, one for each note. 1t is a
well known fact that the difference in
the tone of reed or string in musical
instrument is due to the difference in the
rate of its vibration. The deepest tones
of an organ, for instance, give only forty
vibrations to second, while the sErill-
est note it is possible for the human ear
to hear is made up of five thousand
vibrations to the second. Now the
reeds in a telephone are all arranged to
vibrate, when struck by the pianoforte
key, between little magnets in such a
way as to break and restore. the through
electric current at each contact, and to
make contact with every vibration.
As the several notes of piece of music
are played on the keys of the instrument,
the electric fluid goes over the wire in
waves infinitely small but varying in
rate according to the different reeds sue
cessively employed.


At the office where the music is to be
received, series of reeds, tuned to
exactly correspond with the first set.
are attached to an extremely sensitive
and reverberative sounding board, which
magnifes, so to speak, the faintest vibra-
ton of any one of these reeds, and con-
verts it into audible sound. This appa
ratus is attached in such way to the
magnet around which the electric cur
rent flows, that whatever reed cores
ponds to the peculiar rate of electric
waves in the wire, will vibrate; and
that vibration, though infnitesimally
slight, is made audible by the sounding
board, and lasts just as long as the waves
continue to come at that peculiar rate.
The rate of the electric waves is con-
stantly changing as different notes are
struck by the sender; but whatever the
rate, and however brief its continuance,
one reed or another on the receiving
instrument feels its vibration, and re-
spends instantaneously. Thus the notes
originally played are reproduced in
exact tone, length and order on the re-
ceiving instrument.


1t is just here that one can appreciate
the value of local battery connection.
Force is indestructible but may become
miRutely attenuated. The electric cur
rent passing over hundreds of miles of
wire becomes almost imperceptible; but
if the alternate stops and assumptions
which makes the successive waves are
caught by repeater" and made to
produce corresponding stops and re-
sumptions in powerful local current,
these latter can be caused to operate the
telephone instead of the feeble original
ones, and the impulse will be made much
more perceptible.


The apparatus here described is the
kind used to reproduce music in New
York and played in Philadelphia
under Strakosch's management.


The new interest law of Connecticut
fixes the rates for future contracts at six
per cent, three hundred and sixty days