The Kenosha telegraph. [volume] (Kenosha, Wis.) 1860-1888, 1878-06-06
ELECTROMAGNETIC.

This, wonderful invention has Great
ed such a widespread interest that we
are confident our readers will be
pleased to read the following descrip-
ton from the New York Evening Post
The most common mistake regard
ing Mi. Thomas A. Edisons latest in
vention, the photograph, is that cleo
tricity has anything to dO with it, or
that the: machine is at all costly or in
any way complicated in it's working.
1t is very fortunate for the genial gen
tleman who manipulated the phono-
graph for the amusement and lnstruc-
ton Of the crowd of persons who con-
stantly throng the room with puzzled
expression on their faces, that the days
when wizards got their deserts at the
stake have passed away.
On a table near the center of the
room was the far-famed photograph
which can be briefly described as fol
lows: A hollow cylinder of brass, about
nine inches long and five inches in di-
ameter, is placed horizontally in very
much the same way that a piece OF
wood or metal is placed between the
chucks of lathe tohe turned; brass
rod runs through the,Genter of the cyl
inder, and at the end of this rod is a
little crank which enables one to turn
the cylinder around at any rate of speed
desired; the rod to which this handle
is fixed has a screw-thnead cut on it's
surface, SO that when the cylinder is
turned it shifts slowly to one side in
such a way that if a pencil is held in a
stationary position against the cylinder
while it is turning, it WAuld trace a
line like the thread Of scEeM. Instead
of using a pencil a diminatiye drum
with only one tympanum ,(the lower
One) is used; firmly attacked to the
under side of this lower tympanum is
a small steel point like the point of a
needle. When the bottom of this drum
is made to vibrate from any cause a
touch, or even the vibration of the air
this steel point will vibrate with it,
and in this simple fact is the whole
secret of the photograph. A thin sheet
of common tin-foil, such as is used to
wrap tobacco in, is placed around the
brass cylinder, which is set in motion !;
the little drum is Low placed so that
the point Of the needle just touches the
tinfoil. The slightest movement of
the tympanum of the drum will make
the needle scratch the surface of the
tin sheet as the cylinder moves. Talk
ing into the open end OF the drum gives
the tympanum this needed vibration.
Suppose that a sentence eight or ten
words long is spoken into the little
drum, and the line which the needle
makes on the tin sheet is examined, the
line is seen to be made up Of tiny dots
which the point of the needle made;
where the pitch of the voice was high,
the vibrations of the drum-skin or tym-
panum We're very rapid, and the dots
were very close together; where the
voice was deep, the dots were farther
apart. Where the sound was very loud.
the vibrations of the tympanum were
very energetic, and the point was push
ed far in, and made very deep indenta-
tions. If, now, the needle point is
placed at the beginning Of this dotted
line and held on the line which the
cylinder turns, exactly the same kind
OF vibration will be impaired TO the
drum by the needle passing over the
lndentations as the drum impaired to