M 
tile ^stence № 
'I**», 
sers at the ^ 
^irried bvthe^ 
oms °n’s term, 5 
•' «perinatal i 
'? ¿e electronic 
Joseph Thomson'; 
to Professor itET 
sit needful to fe 
M matter, ace®* 
toms, each of wise 
to Rutherford 
lilt op of electroE: 
rniber of neplml 
e subjects to I 
in a popular k 
Mention mayiei 
m aj tk Jk 
ric Force 
field can be exprs 
by Faraday, of tr 
ndnetion. He# 
i curved lines, a E 
action at a is 
if contiguous pane 
ally regarded the: 
seems to have ran 
retch across ape 
ipted by Sir J a 
abes as having - 
articles which acce 
: being a se® 1 - 
in. 3] 
ATOMICITY IN ELECTRICITY 
3i 
naty. 
m 1 
“ In addition to the tubes which stretch from positive to 
negative electricity, we suppose that there are, in the aether, 
multitudes of tubes of similar constitution but which form 
discrete closed curves instead of having free ends ; we shall 
call such tubes ‘ closed ’ tubes. The difference between the 
two kinds of tubes is similar to that between a vortex filament 
with its ends on the free surface of a liquid and one forming a 
closed vortex ring inside it. These closed tubes which are 
supposed to be present in the aether, whether electric forces exist 
or not, impart a fibrous structure to the aether.” 
Sir Joseph Thomson has developed and applied in many 
directions the theory of moving tubes of force, but unlike Faraday 
he regarded magnetism as a secondary effect, ascribing magnetic 
fields not to the presence of magnetic tubes but to the motion 
of electric tubes. The conception of lines of electric force stretch 
ing from positive to negative charges presents certain difficulties 
which have often been discussed. There is, for example, the 
case where magnetic fields occur without any manifestation of 
electric force. In order to account for such fields it may be 
supposed that two sets of Faraday tubes exist, starting from 
positive and negative charges respectively. In a steady mag 
netic field the positive and negative tubes may be thought of as 
moving in opposite directions with equal velocities. Such diffi 
culties have led many physicists to reject the idea of the discrete 
existence of electrostatic tubes, in spite of the fact that “ they 
give a natural and simple explanation of the electrokinetic 
momentum in the eether ” (Jeans). 
In a later chapter we shall discuss Thomson’s application 
of the hypothesis of Faraday tubes to the problem of accounting 
for ionization caused by radiation. He assumed that the energy 
travelling outwards with a wave of light instead of being spread 
uniformly over the wave-front, is concentrated in those regions 
where pulses are travelling along the lines of force. Thus the 
picture of a wave-front suggested would be a number of bright 
spots on a dark ground. 
3. Theories of Magnetism 
When we turn from electricity to magnetism we find that the 
theories are less definite and the models less clearly cut. Coulomb 
attempted to account for the phenomena of magnetization by 
the existence of two magnetic fluids. 
The first approach to a molecular theory is due to Poisson, 
who supposed that magnetic materials contained small spheres 
which are conductors of the magnetic fluids, and that their