254 Proceedings of Royal Society of Edinburgh. [sess. 
The thermometer is an ordinary Beckmann thermometer, gradu- 
ated into hundredths of a degree C. The temperatures were easily 
read to 0*001° C. by means of a telescope. 
The method of procedure was that described by Abegg (Joe. cit.). 
The following table contains the data of the experiments per- 
formed. In the table — 
a = grams of solution. 
b — grams of Ha 6 C 12 0 12 (anhydrous). 
n = number of gram-molecules in 1 litre. 
A = the observed depression of the freezing-point. 
A \n — the molecular depression. 
a = the molecular depression divided by T87 (van’t Hoff’s 
constant). 
Series I . — Temperature of bath - 1*30° to - 1*25° C. 
a 
b 
n 
A 
A In 
a 
71*48 
0-06121 
0-00181 
0-020 
11-07 
5*92 
73*48 
0-12243 
0-00352 
0-034 
9-67 
5-17 
78-47 
0-27455 
0-00738 
0-064 
8-67 
4-64 
83-45 
0-42666 
0-01079 
0-091 
8-44 
4-51 
88*44 
0-57878 
0-01381 
0-112 
8-11 
4-34 
98-49 
0*88531 
0*01896 
0-144 
7-59 
4-06 
Series II . — Temperature of bath - 1*00° C. 
a 
b 
■ n 
A 
Ain 
a 
51-46 
0-09581 
0-00393 
0-037 
9*42 
5-04 
53-47 
0-19162 
0-00756 
0-062 
8-20 
4-39 
63-45 
0-6678 
0-02221 
0-165 
7-43 
3-97 
69-05 
0-9059 
0-02770 
0195 
7-04 
3*77 
The two series of determinations were made with two inde- 
pendent solutions of sodium mellitate. 
It is my intention to continue these experiments on a larger 
scale during the winter, and to extend them to salts of pyridin- 
pentacarboxylic acid, and of other polybasic acids. 
