Morning journal and courier., 1881-06-11
sSournal arro Courier.
Saturday Morning. June IL, 1881.
A NEW TELEPHoNE,

1t was not to&be expected that restless in.
ventors would remain remain long satisfied
with the telephone now in general use, and
the announcement of new one is, therefore,
not surprising. 1t is the invention of Pro-
fessor Dolbear, instructor in physics at
Tufts college, and is claimed to be in several
PARTICULARS an improvement on the Bell tele-
phone. Among the alleged advantages of
the new instrument are: That it permits
of communication over much greater dis
tances than can be covered now; that it is
free from the disturbing sounds which are
SO annoying now; that the receiver, or that
part of the instrument which is held to the
ear, is much more durable and reliable, be-
cause Of the greater simplicity ofsits mechan-
ism that it can be manufactured at smaller
cost; that by dispensing with the permanent
magnet the expense and inconvenience Incl
dent to renewals of these magnets is avoid
ed and that the receiver, being much light
or in weight, is correspondingly more con
venient in manipulation.
The invention embedies a new method of
making available the electrical current for
the transmission of sound The primary
is the power of magnetism; that in the
method of the Dolbear telephone is the
power of electrical attraction. The differ
ence is thus explained by Professor Dolbear
''That rubbing piece of amber will endow
it with the property of attracting other bod
les has been known from remote times. Sui
phur, wax, glass. and few other substances
were found to possess the same quality
But there are other ways of generating cleo
tricity that are familiar enough nowadays
for example, the galvanic battery; but this
does not exhibit the attractive property of the
piece of rubbed glass in way that is appre-
ciable by ordinary means A well excited piece
of glass will make pith ball move toward it
from distance of foot or more But let
the pith ball be brought very near to
any part of battery or wire
attached to a battery and no ap-
preciable motion will take place. If
however, the wires connecting the terminals
of the battery be wound into helix that
encloses piece of iron, the latter will be
made magnet by the current of electricity
in the wire, and this magnet will attract
other bodies. A very strong magnet will attract
any body whatever, even pith ball or piece of
hard rubber, but the strongest electro-mag-
net hitherto made will not attract such a
substance to itself from distance of half an
inch. The attractive property manifested by
the iron is called magnetism, and the CORE
spending property of the glass that has been
subject to friction is called electrical attrac-
ton This principle of the attractive power
of an electrified body for other bodies is the
basis of the new speaking telephone" The
Dolbear receiver, which contains the impor-
tant part of the invention encloses two plain
iron disks of two inches diameter each, of
the thickness of piece of heavy writing
paper. One of these disks is firmly attached
to the interior of the knob, the other, slight
ly separated from it, is secured, at its edge
only, against the interior of the knob. leav-
ing the centre free to vibrate. The electric
wire is passed through the side or edge of
the knob and connected with one of the
plates, and, as intimated above, the sound is
transmitted by means of the electrical at
traction of the discs.
An experimental test against resistance
equal to 5000 miles of wire has been made
with the Dolbear telephone, and under this |
test the articulation of speech was perfect
and loud enough for all practical purposes. |
1t may be added that Connecticut is entitled
to some credit in this matter, for, like many |
other inventors, Professor Dolbear was born |
in this State lat Norwich in 1S370