Daily globe. [volume] (St. Paul, Minn.) 1878-1884, 1879-12-26
EDIS0N'S ELECTRIC LIGHT.
THE GREATINTENIORM MAKES ANEW
AND REMARKABLE DISCOVERY,
The World to be Revolutionized by a
Charred Cotton Thread-No Further Use
Whatever for a Mine OF Platinum-Elec-
trio Lights Cheaper than Oil-How the
Electric Current Is subdivided and ReRu-
From the New York Herald. ]

AluAoOA eASCvIAV ASuG ~ prOuuCeO 1rOm
little piece Of paper-a tiny strip that a
breath would blow away. Through this lit
tie strip Of paper is passed an electric cur
rent, and the result is a bright, beautiful
light, like the mellow sunset of an Indian
autumn. Edison makes the little piece Of
paper more infusible than platinum, more
durable than granite. And this involves no
complicated process. The paper is merely
baked III an oven until all its elements have
passed away except its carbon framework.
The latter is then placed in glass globe
connected with the wires leading to the
electricity producing machine, and the air
exhausted from the globe. Then
the apparatus is ready to give out q light
that produces no deletorious gases.
no smoke, or offensive odors-a light with
out fame, without danger, requiring no
matches to ignite, giving out but little heat,
vitiating no air, and free from all Pickering;
light that is q little globe of sunshine, q
veritable Aladdin:s lamp. And this light,
the inventor claims, can be produced cheaper
than that from the cheapest oil.
Sitting one night in his laboratory re-
fecting on some Of the unfinished details,
Edison began abstractedly rolling between
his fingers piece of compressed lampblack
mixed with tar for use in his telephone. For
several minutes his thoughts continued far
away, his fingers in the meantime mechanic
ally rolling out the little piece of tarred lamp
black until it had become slender filament.
Happening to glance at it the idea occurred
to him that it might give good result as
burner if made incandescent. A few minutes
later the experiment was tried, and, to the
inventors qualification, satisfactory, al
though not surprising, results were obtained.
Further experiments were made, with altered
forms and composition of the substance, each
experiment demonstrating that at last the
inventor was upon the right track. ~
=. A COTTON THREAD.
A spool OF cotton thread lay on the table
in the laboratory. The inventor cut off
small piece, put it in groove between two
clamps Of iron, and placed the latter in the
furnace. The satisfactory light obtained from
tho tarred lampblack had convinced him
that flaments of carbon of texture not
previously used in electric lighting were the
hidden agents to make thorough success of
incandescent lighting, and it was with this
view that he sought to test the carbon re-
mains Of cotton thread. At the expiration
OF an hour no removed the iron mould con-
tanning the thread from the furnace and took
out the delicate carbon framework of the
thread-all that was left of it after it's fiery
ordeal. This slender filament he placed in
globe and connected it with the wires lead
ing to the machine generating the electric
current. Then he extracted the air from the
globe and turned on the electricity. 81
Presto! a beautiful light greeted his eyes.
he turns on more current expecting the
fragile. filament instantly to fuse; but no, the
only change is q moro brilliant light. He
turns on more current, and still more, but
the delicate thread remains entire. Then,
with characteristic impetuosity and wonder
ing, and marveling at the strength of the
little hlament, he turns on the full power of
his machine and eagerly watches the conse-
quence. For minute or more the tender
thread seems to struggle with the intense
heat passing through it-heat that would
melt the diamond itself-then at last it sue
cumbs and all is darkness. The powerful
current had broken it in twain, but not be-
fore it had emitted light of several gas
jets. Eagerly the inventor fastened to ex-
anime under the microscope this curious
filament, apparently so delicate, but in real
ity much more infusible than platinum. 40
long considered one Of the most infusible of
metals. The microscope showed the surface
OF the dlament to be highly polished and its
parts interviewer with each other.
THE PAPER LIGHT.
It was also noticed that the flament had
obtained remarkable degree Of hardness
compared with Its fragile character before it
was subjected to tho action of the current,
Night and day, with scarcely rest enough to
eat hearty meal or catch a brief repose,
tho inventor kept up his experiments, and
from carbonizing pieces of thread he went
to splinters of wood, straw, paper, and many
other substances never before used for that
purpose. The results of his experiments
showed that the substance best adapted for
oarbonization and the giving out of incan-
descent light was paper, preferably thick like
cardboard, but giving good results when yerv
thin. The beautiful character of the illu-
minstion and the steadiness, reliability.
and non :fusibility of the carbon filament
were not the only elements incident to the
new discovery that brought joy to the heart
OF Edison. There was further clement
not the less necessary because of its being
hidden-the element of proper and uni
form resistance to the passage of the electric
urrent. ~ 49, -.A
The inventors efforts to obtain this ele-
mont had been by far the most laborious of
any in the history of his work from the time
he undertook tho task, and without it abso-
lutte success to electric incandescent illuai-
nation could not be predicated, even though
all the other necessary properties were pres
ent in the fullest DECREE = f@iz -
Passing over the scores OF experiments
made since the the discovery that the carbon
framework of little piece OF paper or
thread was the best substance possible for
1ncandescent lighting, we come to consider
the way in which the same is prepared at the
present time in the laboratory.
s MAKING THE PAPER CARBON.
With suitable punch there is out from
piece of Bristol cardboard q strip of the
same in the form of miniature horseshoe,
about two inches in length and one-eiehth
of an inch in width. A number of
these strips are laid fatwise in
wrought iron mould about the size
OF the hand and separated from each other
by tissue paper. The mould is then covered
and placed in an oven, where it is gradually
raised to temperature of about 600 de-
grees Fahrenheit. This allows the volatile
portions of the paper to pass away. The
mould IS then placed in furnace and
heated almost to white heat, and then re-
moved and allowed to cool gradually. On
opening the mould the charred remains of
the little horseshoe cardboard are found.
Il must be taken ont with the greatest care,
else it will fall to pieces. After being re-
moved from the YnOnl6 n ia rlannd i, a
little globe and attached to the wires leading
to the generating machine. The globe is
then connected with an air pump, and the
latter is at once set to work extracting the
air. After the air has been extracted the