877 
alcoholic solution of the salt in a trough, which contained platinum 
electrodes 2 cm distant from each other. A potential difference of 
100 volt was applied. At 18° the current density was 75 milli- 
amp./em* and in the viscous solution just above the freezing point 
of aethyl-aleohol (— 118°) 30 milliamp./em?. I also worked with a 
dilute solution in amyl-aleohol (—134°). With a spectral apparatus 
of very great dispersion I observed in this case considerably broadened 
and diffuse absorption bands, tiie aspect of which did not change 
when the current was made. It must be remarked however that 
under these circumstances the velocity of the negative ion is very 
small as yet. 
Physics. — “The calculation of the molecular dimensions from the 
supposition of the electric nature of the quasi-elastic atomic 
forces”. By Dr. J. J. van Laar. (Communicated by Prof. 
H. A. Lorentz). 
(Communicated in the meeting of October 31, 1914). 
1. In four papers’), in which some new relations between the 
critical quantities were given, | have also tried to determine the 
form of the function b= f(v,7). While the dependence of 5 on the 
volume appeared to be pretty intricate — that namely the found 
relations at the critical point and at the same time the limiting 
condition at v=v, be satisfied —- the dependence on the temperature 
could be given by a very simple relation, namely (see LI, p. 1053, 
formula (36) ): 
bg — (Po) 9.041 ea PaaS Gok NM 
(6) 
in which (4,) represents the value of the limiting volume /, = »,, 
extrapolated from the direction of the so-called straight diameter 
at 7). This formula was an extension of that which was found at 
the eritical point, namely (loc. cit. p. 1051): 
by — (6,) 
(2) 
in which y; is the coefficient of direction of the “straight diameter” 
in the neighbourhood of the critical point. The table (p. 1052) cal- 
culated to support this relation may be reproduced here. 
Ss Biv A = OV or Re ee Ve Cp 
1) These Proc. of March 26, April 23, May 29 and Sept. 26, 1914, 
