CONSTITUTION AND TEMPERATURE ON MAGNETIC SUSCEPTIBILITY. 
255 
determine the value of the applied pressure corresponding to the maximum of the closed 
area on the p diagram. We cannot expect this method to give us anything hut an 
approximate value of tt because the extrapolation beyond laboratory pressures Is 
considerable, but the results of the calculation are suggestive. 
The relations between the temperature of fusion (S') and applied pressure {p) in 
atmospheres, for the substances'^ here referred to are taken from ‘ Kristallisiereii und 
Schmelzen’ by G. Tammann, Leipzig, 1903, p. 204, et seq. 
For tvater Tammann found 
S-22 = 0-00438 . (p-2200)-77 x 10"®. {p-2200Y. 
Differentiating and equating ^ to zero. 
3S 
dp 
= 0-00438-154 X 10-®. (j;)-2200) = 0, 
or 
TT = 
0-00438 + 154X 2200x 10 
-8 
Benzophenone — 
154x 10-® 
== 5000 atmospheres = 5x10® dynes/square centimetre. 
S = 48-11 + 0-02757^-0-00000136 
0S 
Differentiating and equating — to zero we find the intrinsic pressure 
A cetophenone — 
Aniline- 
Nitrohenzene- 
Xylene- 
Benzene — 
TT = 10,000 atmospheres. 
S= 19-2 + 0-0235^-0-00000152 .p" 
TT = 7700 atmospheres. 
S= -6-1 + 0-0203J3-0-00000112 
TT = 9000 atmospheres. 
S = 5-67 + 0-02344p-0-00000116.p® 
TT = 10,000 atmospheres. 
S = 13-2 + 0-03438^-0-00000171 .y 
TT = 10,000 atmospheres. 
S = 5-43 + 0-0283p-0-00000198p® 
TT == 7100 atmospheres. 
* Most of these substances show a change of diamagnetic susceptibility on crystallization. See Part I., 
pp. 120-131 j Part III., pp. 96-97. 
VOL. CCXX.—A. 2 N 
