He
made use of a glass vessel similar and similarly fitted up to that
known as the electric egg (see Fig. 89). To the lower rod he attached a
cylinder of pure carbon, an inch or so in length, and nearly half an
inch in diameter. To the upper rod he affixed a bundle of fine platina
wires. He now exhausted the air from the balloon, and the distance from
the wire to the carbon being about two inches, he then passed an
inductive current by Ruhmkorffs apparatus.
The
luminous arc was suffused with a red tint on the side next the carbon
to a short distance from the platina; the part which enveloped the
extremity of the platina wires was a violet-blue.
This
disposition of the apparatus was constantly maintained; and the
experiment lasted more than a month without interruption, excepting the
time necessary to recharge the pile. At the completion of this time a
slight black layer of carbon had been deposited on the wires. This
layer, viewed through a magnifying glass, presented nothing very
distinct; but to the compound microscope, with magnifying power of
about thirty diameters, it offered several interesting features. Upon
the wires, and especially upon their extremities, certain separate
points were discoverable, which appeared to belong to octahedral
crystals.
An experienced crystallographer confirmed this
