[ "2 
XII. The Electron llieory of Matter and the Explanation of 
Magnetic Properties. By G. A. Schott, University College 
. of Wales, Aberystwyth*. 
§ 1. TX a previous series of communications to this 
JL Journal it has been shown that spectrum-lines 
cannot be ascribed to the free vibrations of systems of electrons 
in orbital motion of atomic dimensions, partly because the 
intensities of most of the waves emitted are far too small to 
produce observable effects, partly because the wave-lengths 
of those waves, which are of sufficient intensity, are generally 
far too short. When we consider the experimental evidence 
in favour of the view that the atoms of a gas, which absorb 
and emit light, are only a small fraction of the whole number — 
for instance the researches of Stark f and his associates in 
the canal-ray spectrum, the recent work of PfHiger J on the 
absorption in a Geissler tube, and of Wick § on the fluores- 
cence of resorufin, — we are led to the conclusion that spectrum 
lines are due to some special mechanism in the atom, which 
is set in operation during the act of ionization and operates 
only as long as the ion lasts, but is unaffected by disturbances 
which are sufficient only to produce free vibrations of the 
electrons of the atom without altering its structure. 
Be this as it may, spectroscopic phenomena throw much 
less light on the structure of the average atom than has 
hitherto been supposed : we are thus driven to seek information 
from other sources, such as the phenomena of magnetism. 
§ 2. It has been shown by Richarz || and E. Lang IT that 
an electrolytic ion, revolving in an orbit of atomic dimensions 
with a period either greater or less than those of light-waves, 
is equivalent to a molecular magnet, whose moment is of the 
order of one twenty-fifth of the average moment of an atom 
of iron magnetized to saturation. We conclude that an atom 
built up of revolving electrons is capable of accounting for 
magnetic phenomena, provided a sufficiently large proportion 
of the atoms of the substance are effective. 
More detailed investigations by Voigt ** and by J. J. 
Thomson tfj however, indicate a peculiar difficulty, in so far 
as they lead to the conclusion that an assemblage of mutually 
independent electrons, revolving in elliptic orbits, give on 
* Communicated by the Author. 
t Stark, Drude Ann. xxi. p. 401. 
% Pfliiger, Ann. d. Phys. (4) xxiv. p. 515. 
§ Wick, Phys. Ztschf. viii. p. 181. 
|| Richarz, Wied. Ann. lii. p. 410. 
51 R. Lang, Drude Ann. ii. p. 483. 
** Voist, Drude Ann. ix. p. 115. 
tt J. J. Thomson, Phil. Mag. [6] vi. p. 673. 
