The Democratic advocate. [volume] (Westminster, Md.) 1865-1972, 1877-03-31
THE TELEPHONE.

graph wire stretched upon poles in I'll
usual way, individuals may converse wit
each other in audible tones, although sci
arated by hundreds Of miles Of space.
man in Boston may sit at his desk in Stat
street, and converse with his partner q
| friend in Wall street, New York, with a
much ease and facility as if they were sil
ting side BY side. This is indeed stu
pendous achievement, and affords evidenc
that the hidden powers of Nature are cola
petent, when understood, to bring all tn
nations Of the earth into instantaneou
verbal communication with each other.
The telephone is the invention Of Prof
A. Graham Bell, Of Boston, and has re
suited from a course Of induetiye reason
ing, growing out of a careful study Of th,
philosophy Of sound, as related to wave
motions 10 air, and in metals when induced
by electrical excitation. The instrumea
is exceedingly simple and inexpensive, and
easily understood. 1t consists in attach
ing to the terminals Of the ordinary tele
graph wires between any two points pow
erful compound magnets, with coils O.
wire connected In front of the poles
surrounded by these coils of wire, is placed
diaphragm Of iron. A modth-pieco tc
converge the sound upon this diaphragm
substantially completes the arrangement
When the human voice causes the diaph.
ragm to vibrate, closing and breaking the
circuit with each vibration, electrical un.
dulations are induced in the coils precisely
analogous to the undulations Of the all
produced by the voice. These coils arc
connected with the line wire which may
be Of any length, provided the insulation
be good. The undulations induced ia
these coils travel through the line wire,
and, passing through the coils of an IN
strument Of precisely similar construction
at the distant station, are again resolved
into air undulations by the diaphragm Of
this instrument.
In order to attach this device to any
lines of telegraph, it is only necessary to
remove connection with the batteries, close
the circuit and the work is done. The
wire serves the purpose of a speaking tube
and when cities and towns are connected
the results are the same as if the most per
feet tubes were in use for the purposes Of
communication. How far this result can
be made to reach is as yet undetermined,
but experiments show that the commune
cation is perfect through wires two hun
dred miles in extent.
The Scientific American says We
have already laid before our readers ac-
counts Of the wonderful performances Of
Professor Bells telephone, an instrument
remarkable not merely for its phenomenal
capabilities but also because of its having
been brought to its present stage of devel
opment within the period which has elapsed
since June last. During that month, Pro.
fessOr Bell exhibited the apparatus at the
Centennial, working it over short distances
only, and causing it to transmit sound
which reached the opposite terminus very
much diminished in intensity. Without
undertaking to follow the inventor through
his various improvements, it will suffice
here to state that the telephone has re.
Gently carried the human voice over dis.
tance Of l43 miles (from Boston to North
Conway, N. H., SO that ordinary conyer.
sational tones uttered at one end were dis.
tinctly audible atthe other. Further even
than this, the inventor and his assistant
have talked through a wire arranged 10
give an artificial resistance equal to 40 900
ohms, which is more resistance than the
entire length Of the Atlantic sable would
offer. There are, however, other obstacles
than the resistance, which checks the
Transmission of the voice over such i'm
mense distances. These the inventor is
now endeayoring to overcome; and at the
first favorable opportunity, practical test
Of the powers Of the instrument over one
ofthe transatlantic cables viii be attempted.
The apparatus is all contained in an OBJ
long box about inches high and wide,
and II inches long. This is all there is
visible of the instrument, which during
the lecture is placed on a desk at the front
Of the stage, with its mouthpiece toward
the audience. Not only was the conyer-
sation and singing OF the people at the
Boston end distinctly audible in the Salem
hall, IA miles away, but Professor Bells
lecture was plainly heard aud applause sent
over the wires by the listeners in Boston.
Professor Bell was born in Edinburgh,
Scotland, and came to this country about
six years ago. His father, Professor A.
Nj. Bell, who became noted as the inyen-
tor of method for teaching deaf mutes to
speak, and of universal system of phono.
graphy, is now living in Brantford, 0nta-
rio. Professor Graham Bell, the present
inventor, has also been exceptionally sue
cessful in the instruction of deaf mutes,
and in one case he has enabled girl who
had never produced an articulate sound to
pronounce words distinctly after having
her under his tuition for the short space
of two months. "If l can make deaf
mute talk, the now famous inventor is
reported to have said, II can make iron
talk" We need not add that his promise
has been fulfilled.