1132 
The total potential energy of the pair of molecules is then: 
“tg Um Fr UH SG eee (13) 
The two molecules of the pair together contribute to the mag- 
netic moment in the direction of the field AZ the amount: 
BO or ee 
The number of pairs of molecules in the element 
dr dy dO, dO, dw dp 
of the x, x, 0, As, W, p-hyper-space is, according to Leiden Comm. 
Suppl. N°. 246 equation (49): 
NR Np je 7 
———e  r'siny sin 0, sin @, dr dy dO, dO,dpdp . . (15) 
16 ” v 
These pairs contribute to the magnetic moment in the direction 
of H the amount: 
nx 2n 2n 
La ele —hu 
se arf INNNE ‘ Qr’ sin y sind, sin, drdy dO, dO, dw dp.(16) 
nv 4 
¢ 00.0 0 0 
Here n has been written for the number of molecules in the 
volume v of the gas and 4 = a 
The mean contribution of each single molecule is, when we 
consider only the first two terms in the development: 
1 1 
pi hie, — em (hHu) 2 2 2 2. (IN) 
Their number is found by diminishing n by twice the expression 
(15), integrated over all variables. The contribution of the single 
molecules added to (16) gives: 
1 iat 
gem, hip, E op a (itu, 7 
THU Wn Br 
B wad Le “2 + Sha, — Fe er | i 
700000 
sin y sin 0, sin 6, dr dy dO, dO, dw dy. 
If the mutual action of the quadrupoles and of the dipoles were 
neglected, then these molecules would give a magnetic moment 
that might be obtained from (18) by substituting a MH tonen 
This mutual action thus gives rise to an increase of the magnetic 
moment of the gas. This increase has the value: 
