and Temperature on Magnetic Susceptibility. 283 
from a liquid into a gel, it is interesting to note that Chaudier* 
has found that the specific magnetic rotation of such substances is 
continuous, a discontinuity appearing only when crystallisation 
sets in. 
On the theory of diamagnetism developed by Langevin+, the 
above experiments indicate that in the quasi-chemical compounds 
formed during aggregation or crystallisation the internal structure 
of the molecule or atom is modified. This result was assumed in 
the investigation cited at the beginning of this note. 
Tt will be observed that an exact interpretation of the experi- 
mental facts must necessarily be highly speculative in view of the 
present state of the electron theory of valency and further dis- 
cussion of the quantitative results is reserved until an early 
date. 
* Comptes Rendus, t. 156, p. 1529, May 1913. 
+ A complementary theory to that of Langevin has recently appeared dealing 
with the diamagnetism of conducting substances and the part played by free 
electrons (Schrodinger, Sitz. d. k. Akad. Wien cxxt. p. 1305, 1912). In dealing 
with organic liquids the diamagnetic effect due to this source is negligibly small. 
Note. In the paper “The Variation of Magnetic Susceptibility 
with Temperature. Part 11. On Aqueous Solutions” (Proc. Camb. 
Phul. Soc., Vol. Xvit. p. 65) the temperature coefficient given at 
the foot of p. 75 is due to du Bois. The recent work of Weiss 
and Piccard, referred to above, shows that this value is incorrect, 
but the change does not affect the numbers given in the tables 
on pp. 76—77. 
It should be mentioned that the susceptibilities given by 
Jaeger and Meyer are referred to unit volume of the solutions. 
As, however, the density of a solution is very approximately a 
linear function of the absolute temperature, over the interval 
considered, the specific susceptibility is correctly expressed by the 
formula 
Al 
where A, B and Care independent of the absolute temperature (9). 
The conclusions reached concerning the presence of molecular 
complexes are of course unmodified. 
