The true northerner. [volume] (Paw Paw, Mich.) 1855-1920, 1880-01-09

through it-heat that would melt the
diamond itself-then at last it succumbs
and all is darkness. The powerful cur
rent had broken it in twain, but not
before it had emitted light of several
gas jets
Eagerly the inventor FASTENED to ex-
anime under the microscope this curl
Gus flament, apparently so delicate,
but in reality n UGH more infusib than
platinum, so long considered one of the
moss infusible of metals. The micro
scope showed the surface of the fila
ment to be highly polished and its parts
to be interviewer with each other. 1t
was also noticed that the filament had
obtained remarkable degree of hard
ness compared with its fragile character
before it was subjected to the action OF
the current. Night and day, with
scarcely rest enough to eat a hearty
meal or catch brief repose, the in
ventor 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 condemnation and the
giving out of incandescent light was
paper. preferably thick like cardboard,
but giving good results even when very
thin. The beautiful character OF the
illumination and the steadiness, relia-
bility, 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 element--not the
less necessary because of its being hid
den-the element of proper and uni
form resistance to the passage of the
electric current. The inventors efforts
to obtain this element had been by far
the most laborious of any in the history
of his work from the time he undertook
the task, and without it absolute sue
cess to electric incandescent illumina-
ton could not be predicted, even though
all the other necessary properties were
present in the fullest degree.
Passing over the scores of expert
ments made since the discovery that
the carbon framework OF q little piece
of paper or thread was the best sub
stance possible for incandescent light
ing, we come to consider the way in
which the same is prepared at the
present time in the laboratory. With
suitable punch there is cut from a
piece of Bristol cardboard strip of the
same in the form of a miniature horse
shoe, about two inches in length and
one eighth of an inch in width. A
number of these strips are laid fatwise
in wrought-iron' mold about the size
of the hand and separated from each
other by tissue paper. The mold is
then covered and placed in an
oven where it is gradually raised t.
temperature of about 800 degrees
Fahrenheit. This allows the volatile
portions of the paper to pass away
The mold is then placed i'll furnace
and heated almost to white heat, and
then removed and allowed to cool
gradually. On opening the mold the
charred remains of the little horseshoe
cardboard are found. 1t must be taken
out with the greatest care, else it will
fall to pieces. After being removed
from the mold it is placed in little
globe and attached to wires leading to
the generating machine. The globe is
then connected with an air-pump, and
the latter is at once set to work extract
ing the air. After the air has been
extracted the globe is sealed, and the
lamp is ready for use.