Year: 1878

iFrom the New York Evening Post


The most common mistake regarding
MIR. Thomas A. Edison's latest invention,
the photograph, is that electricity has
anything TO do with it, or that the ma
chime is at all costly or in any way COM
plicated III its working. A reporter paid
visit yesterday to room No. 80 in the
Tribune building, and what follows is an
accurate account of what he heard and
saw. 1t is very fortunate for the gentle
men syho manipulated the phonograph
for the amusement and instruction of the
crowd of persons who constantly throng
the loom with a puzzled expression on
their faces, that the days when wizards
gottheir deserts at the stake had passed
sawaF a# 80


Or a table near the center OF tho 4ooala
was the far-famed phonograph, which
can be briefly described as follows: A
hollow cylinder of brass, about nine
inches long and five inches in diameter,
is placed horizontally in very much the
same way that piece. of wood or metal
is placed between the chucks of lathe
to be turned brass rod runs through
the center of the cylinder, and at the
end of this rod is little crank which en-
ables one to turn the cylinder around ut
any rate of speed desired the rod to
which this handle is fixed has screw
thread cut on its surface, so that when
the cylinder Is turned it shifts slowly to
one side in such way that if pencil is
held in a stationary position against the
cylinder while it is turning it would
trace line like the thread of a screw.
Instead of using pencil diminutive
drum with one tympanum (the lower
one) is used; firmly attached to the un-
der side of this lower tympanum is a
small steel point like the point of a
needle.x When the bottom of this
drum is made to vibrate for 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 phonograph. 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 mo-
ton; the little drum is now placed so
that the point of the needle just touches
the tin foil. The slightest movement of
the tympanum of the drum will make
the needle scratch the surface of the tin
sheet as the cylinder moves. Talking
into the open end of the drum gives the
tympanum the needed vibration. Sup
pose that sentence eight or ten words
long is spoken iuto 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 diets which the point
of the needle made where the pitch of
the voice was high, the Vibrations cf the
drum-skln or tympanu1n were very
rapid, and thus dots were very close to-
fl,a
dots were farther apart. Where the
sound was very loud, the vibrations of
the tympanum were very energetic, and
deep indentations. II, now, the needle
point is placed at the beginning of this
dotted line and held on the line while
the cylinder turns, exactly the same
kind of vibrations will be impaired to
the drum by the needle passing over the
indentations as the drum impaired to
the needle when the indentaIons were
made. IF the indentations are very
close together the vibrations of the drum
skin will be very rapid, and the note
heard will be eorrespondinglyh high, and,
under contrary orditisns, the note will
be correspondence low. I[4sA3t ~


The voice of the phonograph, in its
present state of perfection, is that of a
person talking in loud voice in an ad-
joining room with the door closed. Any
sound, no matter what, is faithfully re-
produced-laughing, whisting, cough
ing, singing and ordinary speaking.
The invention is yet in its infancy, and
what may be the Improvements which
will speedily and probably follow it is
impossible to say. Mr.. Edison has al
ready succeeded in making the phono-
graph sufficiently delicate to record and
reproduce the words of speaker, talk
ing in an ordinary way, four feet from
the instrument. The power with which
the sound can be reproduced depends
entirely on the species of sounding
board which is used, and on this point
more decided results will no doubt soon
be obtained. At present. in large
room full of persons, there is no diff
Guilty in hearing the words distinctly
from all parts of the room. The amount
of talking which can be recorded on
small piece of tinfoil is marvellous. Mr..
Edison has succeeded in putting 48, 600
words on sheet of tinfoil ten inches
square. So far, thin copper sheets have
been found to work most atisfr,ctorily,
and it is probable that diamond points
will ultimately be used. Mr.. Edison is
confidert that he will soon be able to
reproduce the slightest whisper as well
as the screech eff steam whistle.