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
current was turned on slowly so as to prevent the cracking of the
button. The button was heated to the point of fusion, and when it
melted it did not, apparently, glow with the same brilliancy as
before, and this would indicate a lower temperature. Leaving out of
consideration the observer's possible, and even probable, error, the
question is, can a body under these conditions be brought from a solid
to a liquid state with evolution of _less_ light?

When the potential of a body is rapidly alternated it is certain that
the structure is jarred. When the potential is very high, although the
vibrations may be few--say 20,000 per second--the effect upon the
structure may be considerable. Suppose, for example, that a ruby is
melted into a drop by a steady application of energy. When it forms a
drop it will emit visible and invisible waves, which will be in a
definite ratio, and to the eye the drop will appear to be of a certain
brilliancy. Next, suppose we diminish to any degree we cho