464 Proceedings of the Royal Society of Edinburgh. [Sess. 
Taylor and Ranken.* The only change made was that sodium hydroxide 
in aqueous alcohol, followed by concentrated nitric acid, was frequently 
employed, instead of chromic acid in sulphuric acid, to clean out the 
viscosity tubes. The transpiration times of pure water for each tube were 
determined just before the determination of the transpiration times for 
each solution ; this is an absolutely necessary precaution. It is unnecessary 
to reproduce tests which were made to check the accuracy of the deter- 
mination of the viscosity. It may be taken to be the same as mentioned 
in our previous paper. 
Experimental Results. 
In the following tables — 
m is the concentration of the solution in mols. per 1000 gm. of water. 
d is the density of the solution referred to water at 4° C. 
7 ]/rj 0 is the ratio of the viscosity of the solution to that of the solvent at 
the given temperature, as directly determined by experiment. 
i] is the viscosity of the solutions in absolute units, and is obtained 
from the ratio given in the third column by multiplication with rj 0 
as determined by Thorpe and Rodger f ( tj 0 at 25° C. = 00891, at 
35° C. = -00720). 
Tetra-Methyl Ammonium Iodide. 
25.° 0. 
m 
d 
vho 
V 
•0685 
1-0022 
1-0042 
00894 
•1300 
1-0064 
1-0060 
•00895 
•2550 
1-0149 
1-0124 
•00898 
35°. 
m 
d 
vho 
V 
•1106 
1-0019 
1-0036 
•00723 
1527 
1-0050 
1-0076 
•00726 
•1774 
1-0065 
1-0127 
•00729 
* Loc. cit. 
t Phil. Trans., 185, p. 449, 1894. 
