The true northerner. [volume] (Paw Paw, Mich.) 1855-1920, 1880-01-09
LIGHT FROM PAPER.
Edison's wonderful Discovery, and How He
stumbled On Ii.

LlUHl FhVM Il Al Ehs
Edison's wonderful Discovery. and How He
Stumbled On 1t.
From the New York Herald
Edison's electric light, incredible as
it may appear, is produced from lit
tie piece of paper "a tiny strip OF
paper that breath would blow away.
Through this little strip of paper is
passed an electric current, and the re-
suit is bright, beautiful light, like the
mellow sunset of an Italian autumn.
Since September, 1873, Edison has been
hard at work in his laboratory. Expert
ment after experiment was tried. The
task he had before him was the produc-
ton of pure and steady light ut cost
which should be. less than that OF gas. OF
the two systems before him-the voltaic
and the incandesceat-he chose the
latter. The difficulties in his way were
the liability of platinum to melt and of
carbon to dissipate gradually under in
tense heat He first experimental with
platinum, and by an ingenious arrange
ment of little lever, which worked by
the expansion Of the platinum when
heated, he sought to turn the current
from the incandescent platinum before
the melting point was reached. This
was finally abandoned, for the reason
that the lever would bend and SO be-
come practically useless.
Edison experimental with spirals of
platinum and platinum made in the
form of bobbin and better results
were obtained. The next was unique
idea, making the platinum give the
light as it were by proxy. By means
of reflector he concentrated the heat
rays of the platinum upon q piece of
zircon, causing the latter to become
luminous. Still he was not satisfied,
and his next movement was the adop-
ton of carbon in connection with
platinum as the substances to be made
incandescent. A dozen or more such
lamps were made, but, after all,
the inventor was obliged to return to
platinum as the substance most suita-
bic, all things considered, for being
made incandescent. For two months
he worked at platinum day and night,
only to find that platinum, as he had
been using it, was entirely worthless
for incandescent lighting. He found
that when wires or sheets of platinum,
iridium or other metallic conductors of
electricity that fuse at high tempera-
ture are exposed to- a high temperature
near their melting point in air
for several hours by passing a
current of electricity through them
and chen are allowed to cool, the metal
is found to be ruptured, and under the
microscope there are revealed myriads
of cracks in various directions, many OF
which reach nearly to the center of the
wire. They also lose weight. To over
come this Edison tried the plan of
placing his platinum spirals in glass
globe from which all the air was re-
moved, leaving the spiral in vacuum
This was success. All the air and
gases in the metal were expelled, TIE
platinum did not crack or lose weight,
and beautiful light was obtained.
One by one Edison had thus overcome
the many difficulties that lay in his
path. He had brought up platinum as
substance for illumination from a
state of comparative worthlessness to
one well.nigh perfection. He had sue
ceeded, by curious combination and
improvement i'll air-pumps, in obtain
ing vacuum of nearly one-millionth of
an atmosphere, and he had perfected a
generator or electricity producing ma
chine (for all the time he had been
working at lamps he was also expert
menting in magneto-electric machines)
that gave some 30 per cent in electricity
OF the energy it received from the driv-
ing engine. In word, all the serious
obstacles toward the success of the in
candescent electric lighting, he be-
lieved, had melted away, and there re-
manned but a comparatively few minor
details to be arranged.
There occurred, however, at this
juncture, a discovery that materially
changed the system and gave a rapid
stride toward the perfect electric lamp.
Sitting one night in his laboratory, re-
hecting on some of the unfinished de-
tails, Edison began abstractedly rolling
between his fingers piece of COM
pressed iampblack mixed with tar for
use in his telephone. For several min
utes his thoughts continued far away,
his fingers in the meantime mechani-
cally rolling out the little piece of
tarred lampblack until it had become a
slender filament. Happening to glance
ut it the idea occurred to him that it
might give results as burner if made
incandescent. A few minutes later the
experiment was tried, and, to the in
ventor's qualification, satisfactory, al
though not surprising results, were OBJ
tanned. Further experiments we're
made, with altered forms and compost
ton of the substance, each experiment
demonstrating that at last the inventor
was upon the right track. A spool of
cotton thread lay on the table in the
laboratory. The inventor cut off a
small piece, put it in groove between
two clamps of iron and placed the latter
in the furnace. The satisfactory light
obtained from the tarred lampblack bad
convinced him that flaments of carbon
of texture not previously used in
electric lighting were the hidden agents
to make thorough success of incan-
descent lighting, and it was with this
view that he sought to test the carbon
| remains of n cotton thread At the ex-