688 Mr. W. Sutherland on the Electric 
electron in the cathode rays was found by J. J. Thomson to 
be from 1/500 to 1/1000 of that of a hvdrogen atom, we may 
provisionally suppose the atom of hydrogen to contain from 
250 to 500 electric doublets, whereas in electrolytic theory 
we assign to the hydrogen atom only one negative electron to 
make the hydrogen ion. It is possible, then, that the Harth’s 
magnetism may be due to either the ionic electric charges of 
matter or to the electricity which forms matter. Possibly 
the ionic charges are only a special manifestation of the 
polarity which we assume to be innate in matter if we consider 
its atoms to be made up of electric doublets. 
The fundamental equation for our theory of the Harth’s 
magnetism gives the magnetic potential V at a point 7, 6, 
due to a sphere of radius R revolving round a central axis 
with angular velocity Q and charged with electricity of 
surface density o, thus 
W=4rR'Oc cos 6/57". . . . ee 
For a sphere of radius R having a uniform body charge of 
negative electricity of density p the magnetic potential is 
= °R 
+ OE!) oa: 
‘ r 20 
This is obtained on the assumption that e,e./7? expresses 
the whole law of electric force. If we take account of re- 
pulsions (1—b) ¢/7* and (1—c)e?/r?, we have to give a more 
complex meaning than hitherto to the electric force at a point, 
and therefore also to the magnetic force due to moving elec- 
tricity. In the theory of magnetism due to electric convec- 
tion, magnetic torce at a place is taken to be proportional to 
the electric force exerted at that place by the moving elec- 
tricity. Now the electric force of an electron e’ on another 
e’ at distance 7 has three different values according to the 
natures of e’ and e”. 
If the ether contains electric doublets which give it its 
electric properties, and also by their rotation give it its 
magnetic properties, the magnetic force due to the rotation 
of % of amount e with the Harth at the J of a doublet A in 
the ether outside the Earth will be 1—d times as large as at 
the h in A. The mean magnetic force at A due to the rota- 
tion of $ in the Earth is 1—0/2 times that which would act 
if e*/7? were the universal law. Similarly for p in the Harth 
the magnetic force is 1—c/2 times its value for the one law 
e?/7?. Now the Harth’s magnetic field is directed in the same 
way as if it were caused by the rotation of negative elec- 
tricity with the Earth. Hence ¢ is algebraically less than 0. 
