The Ottawa free trader. [volume] (Ottawa, Ill.) 1843-1916, 1878-06-15

We are indebted to Scribners Monthly for
the following faithful and graphic description
and cut which Mr. Roof, the engraver, has here
reproduced for the benefit of the reader:
In its simplest form, the speaking phono-
graph consists of a mounted diaphragm, so ar
ranged as to operate a small steel stylus placed
just below and opposite its centre, and a brass
cylinder u, six or more inches long by three
or four in diameter which is mounted on a
horizontal axis extending each way beyond its
ends for II distance about equal to its own
length. a spiral groove is cut IN the circum-
ference of the cylinder from one end to the
other, each spiral of the groove being separated
from ITS nelghbor by about onetentn Of an
inch. The shaft or axis is also cut by II screw
thread corresponding to the spiral groove of
the cylinder, and works in screw bearings
consequently when the cylinder is caused To
revovc, by means of crank that is fitted to
the axis for this purpose, it receives Il forward
|Or backward movement of about one.tcnth of
an inch for every turn of the same the dircc-
ton, of course, depending upon the way the
crank Is turned. The diaphragm, G, is sup
ported by an upright casting capable of adj.
justment, and so arranged that it may be re-.
moved altogether when necessary. When in
use, however, il is clampcd in fixed position
above or in front of the cylinder, thus bringing
the stylus always opposite the groove as the
cylinder is turned. \ small flat spring attach
ed to the casting extends underneath the dia
phragm rs far rs its center and carries the
stylus and between the diaphragm and spring.
Il small piece of India rubber is placed toll
modify the action, it having been found that
better results are obtained by this means than
when the stylus is rigidly attached to the dia-
phragm itself.
The action of the apparatus will now be-
readily understood from what follows The
cylinder is first very smoothly covered with
the amplitude of the vibrations of the dia-l
phragm: or, in other words with the infections
or modulations of the speakers voice Thee
infections may therefore DC looked upon ~ a
sort of visible speech. which, in fact. they
really are If now the diaphragm i rclaoycd. /.
by loosening the clamp, and the cylinder then
turned back Ia the starting point, We have only
To replace the diaphragm and turn in the same
direction rs ut first To hear repeated all that
has been spoken into the mouth piece of the
apparatus the stylus, by this means. beng
caused To traverse its former path, and consc
quently, rising and falling with the deprcSsiuns
in the foil, its motion Is communicated Ia the
diaphragm. and thence through the incrvcn-
ing air To the ear, where the sensation uf sound
Is produced.
There are many curious facts connected with
this wonderful instrument, floating through
the public press, and some bits Of information.
Ii Is said that Mr. Edison discovered the
principle Of the speaking monograph through
accident lie was singing in the mouih-piece
of a telephone when the vibrations Of his voice
sent the fine steel pointinto his finger. Could
he record the actions of the point and send the
point over the same surface aflcrward, the
thing would talk. The experiment was made
on strip Of telegraph paper. He -hallooed'
into the mouth- piece, and inden,aiions were