Year: 1878

What &c Can DO Now. and What


Ii Way DO i'm the Future


New York Evening Postl


The most common mistake regarding
| Mr., Thos. A. Edison's latest invention, the
phonograph, is that electricity has any
thing to do with it. or that the machine
Is at all costly or in any way complicated
ing Post paid visit Yesterday to room
No. 32, in the Tribune building and what
follows is an accurate account of what he
heard and saw. 1t is very fortunate for the
genial gentleman who manipulated the
| phonograph for the amusement and in
struction of the crowd of persons who con
stantly throng the room with a puzzled
| expression on their faces, that the days
when wizards got their deserts at the
stake have passed away.


On table near the centre of the room
was the far famed phonograph, which can
be briefly described as follows: a hollow
| cylinder of brass, about niue inches long
and five inches in diameter, is placed hor
iZontaly in very much the same way that
| piece of wood or metal is placed between
the chucks of a lathe to be turned; n brass
rod runs through the centre of the cylin-
der, and at the end of this rod is a little
crank which enables one to turn the cyl
Inder around at 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 slow
ly to one side in such way that if pen
Gil is held in IA stationary position against
the cylinder while 1t is turning it would
trace a line like the thread of a screw.
Instead of using a pencil a diminutive
drum with only one tympanum (the low
er one) is used; firmly attached to the un-
der side of this lower tympanum is small
steel point like the point of 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 sim
pie act is the whole secret of the phOnO
graph. A thin sheet of common tin-fOil,
such as is used TO wrap tobacco in, is
placed around the cylinder, which is set
in motion; the. little drum is now placed
so that the point of the needle just touch
es 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 this needed vibration. Sup
pose that a sentence eight or ten words
long is spoken into this 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 tYmpanum was very rapid,
and the dots were very close together;
where the voice was deep the dots were
further apart; where the sound was very
loud the vibrations of the tympanum were
very energetic, and the point was pushed
far in and made very deep indentatiOns.
If, 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 vibration will be impart-
ed-t9 the drum lay the needle passing
over the 'ndentations as the. drum i'm
parted to the needle when the lndenta
tions 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 correspoudingly high,
and under contrary motions the note will
be correspo spondingly low.


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 pro
duced-laughing whistling, coughing,
singing and ordinary speaking. The in
vention is yet in its infancy, and what
may be the improvements which will
speedily and probably follow is impossible
to say. Mr.. Edison has already succeed
ed in making the photograph sufficient
ly delicate to record and produce the
words of speaker, talking in an ordina
ry way, four feet from the instrument.
The power with which the sound can be
reproduced depends on the species of
sounding board which is used, and on
this point more decided results will no
doubt soon lie qLtained A present in a
large room full of persons there is no
difficulty in hearing the words distinctly
from all parts of the room. The amount
of talking which can be recorded on a
small piece of tin foil is marvellous. Mr.
Edison has succeeded III putting $4,000
words Oh a sheet Of tin-foil about ten
inches square SO far, thin copper sheets
have been found to work most satisfac
torily, and it is probable that diamond
points will ultimately be used. Mr..
Edison is confident that he will soon be
able to reproduce the slightest whisper as
well as the screech Of a steamwhistle,