360 Proceedings of Royal Society of Edinburgh. [sess. 
and mhos for the specific resistances and conductivities of the 
waters at the temperature of 24° C. These were calculated with 
the aid of the constants a and /3 from the resistances found for 
the introduced column of the several samples of water at the 
lower and experimental temperatures. 
The relative densities, d 2i , were determined at the temperature 
of 24° C. 
Table II. 
Water. 
cl 2i . 
I 
P 24 * 
1 
P-24 
a x 10 5 . 
13 x 10 7 . 
No. 1 
1 -02528 
20-8125 ohms 
*048048 mho 
-2814 
+ 4450 
No. 2 
598 
19-9563 ,, 
•050109 ,, 
-2842 
+ 4342 
Natural 
659 
19-1148 ,, 
•052315 ,, 
-2706 
+ 3619 
No. 3 
707 
187744 „ 
•053264 „ 
-2686 
+ 3477 
No. 4 
937 
17-2480 ,, 
•057978 ,, 
- 2695 
+ 3415 
Discussion. 
A close examination of the results given in Table II. failed to 
reveal the existence of any of those simple relationships between 
the resistances and relative densities which I had hoped to find, 
and such as Knudsen observed for the samples of water investi- 
gated by him ; and all attempts to found a general equation based 
upon the data contained in the above-named table, whereby one 
might be enabled to calculate either the correct density or resist- 
ance of a similar water, proved utterly fruitless ; even the best 
formulae obtainable gave but poor approximations to the actual 
values as determined experimentally. 
In the matter of the uniformity of the temperature coefficients, 
it would appear that Knudsen was more fortunate than myself ; 
and that notwithstanding the fact that the variations introduced 
for the total salinities were very great in comparison with those 
dealt with here. It is, however, somewhat surprising that so large 
a divergence should exist between the maximum value found for 
the temperature coefficient by him, and the mean of those given 
under a in Table II., the former being only -0113, whilst the latter 
is *0275. 
Attention may also be drawn to the fact that the Danish 
observer assumes a straight line equation for the temperature 
