incandescent. Fig. 24 illustrates one of the bulbs used. It consists
of a spherical globe L, provided with a long neck n, on the top, for
increasing the action in some cases by the application of an external
conducting coating. The globe L is blown out on the bottom into a very
small bulb b, which serves to hold it firmly in a socket S of
insulating material into which it is cemented. A fine lamp filament f,
supported on a wire w, passes through the centre of the globe L. The
filament is rendered incandescent in the middle portion, where the
bombardment proceeding from the lower inside surface of the globe is
most intense. The lower portion of the globe, as far as the socket S
reaches, is rendered conducting, either by a tinfoil coating or
otherwise, and the external electrode is connected to a terminal of
the coil.

The arrangement diagrammatically indicated in Fig. 24 was found to be
an inferior one when it was desired to render incandescent a filament
or button supported in the centre of the globe, but it was convenient
when the object was to excite phosphorescence.

In many experiments in which bodies of a different kind were mounted
in the bulb as, for instance, indicated in Fig. 23, some observations
of interest were made.

It was found, among other things, that in such cases, no matter where
the bombardment began, just as soon as a high temperature was reached
there was generally one of the bodies which seemed to take most of the
bombardment upon itself, the other, or others, being thereby relieved.
This quality appeared to depend principally on the point of fusion,
and on the facility with which the body was "evaporated," or,
generally speaking, disintegrated--meaning by the latter term not only