212 REPORT—1890. 
electrolyte, ¢/1°85 is the ratio of the number of molecules in unit volume 
of electrolyte to what would be the number in unit volume if there were 
no dissociation. Hence <=¢/1°'85. 
These molecular depressions of the freezing-point have been deter- 
mined by Raoult by observing the effect of the dissolution of one gramme 
of the salt in one litre of water. Hence, if the conductivity of the solu- 
tion of the same strength be known, we have two independent methods of 
determining 7, one of which comes from conductivity measurements and 
the other from thermal measurements, based on the assumption of dis- 
sociation. The results are given in a table (‘ Zeitschr.’ vol. 1, p. 634). 
The numbers in the column based on conductivities are calculated from 
Ostwald for acids and bases, from Kohlrausch for most salts, but some 
also from Long, Grotrian, Klein, and Ostwald. For the better conduct- 
ing salts the figures may be 10 or 15 per cent. in error, interpolation and 
extrapolation having to be used. For worse conducting salts the possible 
error is smaller, and for acids and bases at the most 5 percent. ‘Of 
the accuracy of Raoult’s numbers I am not sure; an error of 5 or 10 per 
cent. seems likely.’! The conductivity was measured at 18° C., or 25° C., 
and the lowering of the freezing-point at about 0° C. Considering all 
this, the numbers seem fairly accordant with certain exceptions,’ of 
1 Arrhenius, ‘B.A. Electrolysis Committee Sixth Circular,’ Zeitschr. 1, p. 636. 
‘2 In a subsequent communication to Zeitschr. f. ph. Chem. ii. p. 491, Arrhenius: 
returns to the consideration of the comparison of the numbers and determines the 
freezing-point depressions, and so redetermines the values of 7. The results are 
contained in the following table :— 
TABLE V.—Table of Comparisons of observed and calculated Values of Freezing- 
point Depression in Aqueous Solutions. 
(From Arrhenius, ‘ Zeitschr. fiir ph. Chem.’ vol. 2.) 
32 138 |e |A 53. Alld 
ga) (ga be Meee) se |eperl eae lean 
Substance Dissolved gs 250/28 Sy (Sou E02 33 | Be lipins 
fo lege |2s [gei2 i (BeVio* jeg 
Pe je2 (88 IS&, |. less as 
3 & oe) amy = hee S = 
A.—NON-CONDUCTORS 
0:319 | 0-100 | 0:184| 1:84 | 0:97 -, 
1. Methylalcohol. 0638 |0:200 | 0°356| 1:78 | 0-94 3 
CH,OH 151 | 0-485 | 0-886] 1:82 | 696 5 
3°00 |0:97 | 1:831] 1:89 | 1:00 2 
0°575 |0:125 | 0-229] 1-83 | 0:97 fo) 
2, Ethylalcohol 1:44 |0:313'| 0-591] 1-89 | 1-00 ‘= 
C,H,OH 285 |0°62 | 1:185| 1:91 | 1-01 = 
570 |1:24 | 2-456] 1:98 | 1:05 = 
0°61 | 0-102 | 0:196| 1:93 | 1:02 = 
3. Propylalcohol 153 | 0-255 | 0-479| 1:88 | 1:00 |\, iS. 
C,H,OH 3°83 | 0°638 | 1:202| 1:89 | 1-00 e 
6:37 |1:06 | 2:065| 1:95 | 1-03 5 
0°61 | 0-102 | 0:193| 1-90 | 1-00 g 
4, Isopropylalcohol 152 | 0-253 | 0-476; 1:88 | 1:00 a 
C,H,OH 3:79 | 0631 | 1:212| 1:92 | 1-01 = 
6:32 | 1-053 | 2:095| 1:99 | 1-05 be 
0:91 | 0123 | 0-249] 2:02 | 1:07 § 
5. Isobutylalcohol 2-28 | 0-308 | 0°591| 1:92 | 1:02 s 
0,H,OH 5°71 | 0-771 | 1-484] 1:92 | 1-02 i) 
9°52 |1:29 | 2:60 | 2:02 | 1:07 5 L 
= 
