236
XIII
EXPERIMENTS ON THE CATHODE DISCHARGE
are connected with the coatings of a large condenser; for it
then often takes place from a state of things in which the
separate discharges can be distinguished by the eye. Once
the change has taken place, the switching of the condenser in
or out of circuit has not the slightest effect upon the appear-
ance of the discharge.
The general conclusion which I draw from the experiments
described is that the discharges tested were continuous: from
this I further conclude that the battery-discharge in general
is to be regarded as continuous, excepting when it exhibits
the known criteria of discontinuity; further, that the dis-
charges of an induction-coil, whose period may, be between
1000 and of a second according to the size of the
apparatus, are to be regarded as being continuous during this
interval.
In order to establish these conclusions fully, it is necessary
to show that the considerations which lead to the opposite
conclusion cannot be regarded as decisive. These conclusions
appear chiefly to depend upon the following experimental
results: (1) that a weak current (e.g. such as an induction-
machine gives) is always discontinuous, and does not become
continuous even when the partial discharges succeed each
other at the rate of several thousand per second; (2) that the
heating effect in a gas-tube is not proportional to the square
of the current, but to the current itself; and (3) that in
accordance with this the potential difference at the ends of
the tube does not increase with increasing current, but per-
found
sists at the value which enables the weakest
current to traverse the tube. In order to show
that these results do not necessarily prove discon-
tinuity, I shall make use of a simple mechanical
analogue. The arrangement which I shall de-
scribe is such that it might in many respects,
-and at any rate in those under consideration,
-replace a gas-tube as a conductor of electricity,
and nevertheless a current would flow continu-
ously through it under certain conditions. Let A (Fig. 29)
represent the anode, and let this be connected by a metallic
spring or other elastic good conductor with the weight a
FIG. 29.