254
XIII
EXPERIMENTS ON THE CATHODE DISCHARGE
we may regard the battery discharge as being continuous, and
therefore the glow discharge as not being necessarily dis-
ruptive.
2. That the cathode rays are only a phenomenon accom-
panying the discharge, and have nothing directly to do with
the path of the current.¹
3. That the electrostatic and electromagnetic properties
of the cathode rays are either nil or very feeble.
I have also endeavoured to bring forward a definite
conception as to how the glow discharge takes place. The
following are the principal features of this:-
The luminescence of the gas in the glow discharge is not
a phosphorescence under the direct action of the current, but
a phosphorescence under the influence of cathode rays produced
by the current. These cathode rays are electrically indifferent,
and amongst known agents the phenomenon most nearly allied
to them is light. The rotation of the plane of polarisation of
light is the nearest analogue to the bending of cathode rays by
a magnet.
If this conception is correct, we are forced by the pheno-
mena to assume that there are different kinds of cathode rays
whose properties merge into each other and correspond to the
colours of light. They differ amongst themselves in respect of
exciting phosphorescence, of being absorbed, and of being
deflected by a magnet.
3
The views which most nearly coincide with these are those
which have been expressed by E. Wiedemann2 and E. Gold-
stein. By comparing this paper with those below referred to,
it will be easy to recognise the points of agreement and differ-
ence. The experiments here described were carried out in the
Physical Institute of the University of Berlin.
1 Since the presence of cathode rays in a gas-space modifies considerably the
possibility of passing a discharge through it, there can scarcely be any doubt
that the position and development of the cathode rays do indirectly affect the
path of the current.
2 See Wied. Ann. 10, p. 249, 1880.
3 Loc. cit. 12, p. 265, 1881.