Harrisburg telegraph. [volume] (Harrisburg, Pa.) 1879-1948, 1919-08-08
Why Talking
Machines Talk
BY GARRETT p. sERVIss

A request is made for information
about the phonograph and particu-
larly about the records and their
composition.
The wonder of these things is sub
siding for us, and yet one can sym
pathize with the cry of "Mein Gott
i'm Himmel!" that fell from the lips
of one of Edison's workmen (Kruesi)
the very one who made the machine
after the inventors directions, when
he heard a human voice issuing
from the first phonograph at Menlo
Park in 1878. But Edison himself
was astonished at the complete sue
cess of his first effort, as he himself
tells:
IL didn't have much faith that il
| would work, excepting that I might
possibly hear word or so that would
give hope of a future for the idea
| Kruesi, when he had nearly finished
| it, asked what it was for. 1 told
| him l was going to record talking
and then have the machine talk back
He thought it absurd. However, il
| was finished. the foil put on; then
! shouted, Mary had little lamb,
| etc.
II adjusted the reproducer and
| the machine reproduced il perfectly
l was never taken so aback in my
| life. Everybody was astonished.
was always afraid of things thai
worked the first time. Long expert.
| ence proved that there were great
| drawbacks found generally before
| they could be got commercial, but
here was something there was nC
| doubt of.
The phonograph was an instant
success because Edison had, at the
first attempt, got into the machine
| every essential element. The essen
| tials were few, and some of the most
important had been stumbled on by
other inventors years before, but they
would not fall into order and work
| except in an atmosphere of genius
| Edison would call it simply an atmo-
| sphere of hard work.
Now, here Is the way Edison made
his first records. and 1t Is still the
ABC of record making, although, OF
course, improvements and some modi-
fcations of methods have been made
The first thing he desired to dc
was to make the vibrations of the
human voice record themselves in
the form of q line of permanent
waves grooved in surface. that
would retain them. For this pur-
pose he took a solid cylinder and
cut on it's surface a spiral groove
winding in close turns from one end
to the other. Then he mounted the
cylinder, placed with it's length hori-
zontal, on a screw whose thread cor
responded exactly in pitch with that
of the spiral groove, so that when
the cylinder was rotated on the
screws as an axle 1t advanced end
wise with a perfectly regular motion
Next a steel pointer, attached to
diaphragm which could be set
vibrating by the sounds of the voice,
was placed in contact with the cylin-
der in such a way that as the cylin-
der rotated beneath it the pointer
always kept exactly over the groove
Finally a cover of tint foil was placed
close around the cylinder. Then
when the steel pointer was caused
to vibrate in accord with the move
ments of the diaphragm, it pressed
with continually changing force upon
the tin-foil stretched over the groove
and thus produced around the cylin-
der a spiral line of indentations OF
greater or less depth corresponding
with the sound waves that moved
the diaphragm and pointer.
This line of materialized sound
waves constituted the record. y
When the cylinder was rotated again
and the pointer was left free to rise
and fall with the varying depth oil
the indentations, it set the diaphragm
into vibrations precisely like those
which the voice of the speaker mao
originally produced, and thereupon
the diaphragm itself became the
speaker, reproducing the words d!
throwing the surrounding air into
the same sort of soundwaVes tha'
had at first acted upon it.
But tinfoil was not a very last
ing substance to carry the record
and. as soon as the success OF the
invention was establihed, many at
tempts were made to find, or create
better material upon when TO I'm
press the indentations. Some klno
Of waxy substance was evidently re-
ouired which would easily take tine
Impressions and at the same time
retain it's shape and resist wear
Various mixtures have been trleu
and paraffin, stearin, and shellac are
the principal ingredients USED. foi
making copies matriX, or mastei
record" is first prepared py electro-
Mating, and from this copies may De
obtained by hydraulic pressure
While the earlier records were
made on cylinders, the common
method now is to employ a rotating
circular plate On this the record Is
made by the same principle as In
the case OF the cylinders, but the
pointer. or stylus. is caused to move
in such a way as to form waving
horizontal lines. instead of indenta-
tions. II you will take a strong lens
and examine the ordinary plate re-
cord you will perceive how BEAUTIFULLY
the line curves trace out the undula-
tions of sound. The lines run about
100 to the inch. but the amplitude
of the waves is measured by thou