The before mentioned difficulty did not exist, however, when the body
mounted in the carbon cup offered great resistance to deterioration.
For instance, when an oxide was first fused in an oxygen blast and
then mounted in the bulb, it melted very readily into a drop.
Generally during the process of fusion magnificent light effects were
noted, of which it would be difficult to give an adequate idea. Fig.
23 is intended to illustrate the effect observed with a ruby drop. At
first one may see a narrow funnel of white light projected against the
top of the globe, where it produces an irregularly outlined
phosphorescent patch. When the point of the ruby fuses the
phosphorescence becomes very powerful; but as the atoms are projected
with much greater speed from the surface of the drop, soon the glass
gets hot and "tired," and now only the outer edge of the patch glows.
In this manner an intensely phosphorescent, sharply defined line, _l_,
corresponding to the outline of the drop, is produced, which spreads
slowly over the globe as the drop gets larger. When the mass begins to
boil, small bubbles and cavities are formed, which cause dark colored
spots to sweep across the globe. The bulb may be turned downward
without fear of the drop falling off, as the mass possesses
considerable viscosity.
I may mention here another feature of some interest, which I believe
to have noted in the course of these experiments, though the
observations do not amount to a certitude. It _appeared_ that under
the molecular impact caused by the rapidly alternating potential the
body was fused and maintained in that state at a lower temperature in
a highly exhausted bulb than was the case at normal pressure and
application of heat in the ordinary way--that is, at least, judging
from the quantity of the light emitted. One of the experiments
performed may be mentioned here by way of illustration. A small piece
of pumice stone was stuck on a platinum wire, and first melted to it
in a gas burner. The wire was next placed between two pieces of
charcoal and a burner applied so as to produce an intense heat,
sufficient to melt down the pumice stone into a small glass-like
button. The platinum wire had to be taken of sufficient thickness to
prevent its melting in the fire. While in the charcoal fire, or when
held in a burner to get a better idea of the degree of heat, the
button glowed with great brilliancy. The wire with the button was then
mounted in a bulb, and upon exhausting the same to a high degree, the
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