1887 .] 
Mr W. Durham on Laws of Solution. 
387 
Heat of Combination. 
[Zn,S0 4 ] - [Zn,Cl 2 ] 
[Cd,S0 4 ] - [Cd,Cl 2 ] 
[Ca,S0 4 j - [Ca,Br 2 ] 
[Zn,S0 4 ] - [Zn,Br 2 ] 
[Li 2 ,N 2 ,0«] - [Li 2 , Cl 2 ] 
[Ca,N 2 ,0 <J ] - [Ca,Cl 2 ] 
[Sr,N 2 ,0 6 ] -[Sr, Cl 2 ] 
[Na 2 N 2 ,0 6 ] - [Na 2 ,Cl 2 ] 
Difference. 
= 132860 
= 128310 
+ 4550 
= 177520 
= 154140 
+23380 
39620 
36820 
+ 2800 
39280 
31120 
• + 8160 
Heat of Solution. Difference. 
+ 2800 
+ 7700 
■ 4900 
- 20070 
- 3400 
23470 
- 16280 
- 13460 
2820 
- 15760 
- 7700 
8060 
The only exceptions to above rule occur when the heat of neutralisa- 
tion differs very greatly from the average, but this difference exactly 
accounts for the discrepancy. Thus in the case of BaS0 4 , the heat 
of neutralisation is abnormal to the extent in which it differs from 
above law. 
2. On the Partition of Energy between the Translatory and 
Rotational Motions of a set of non-homogeneous Elastic 
Spheres. By Professor W. Burnside. Communicated 
by Professor Tait. 
3. On the Salinity, Temperature, &c. of the Firth of Forth. 
By H. R. Mill, D.Sc. 
4. The Direct Measurement of the Peltier Effect. By Albert 
Campbell, B.A. Communicated by Professor Tait. 
(Plate XIII.) 
The researches described in this paper had for their object the 
direct measurement of the Peltier effect, with a view to verify the 
hypotheses regarding it and the laws deduced from these. Hither- 
to it has been a pure assumption that the Peltier effect vanishes at 
the neutral point. As this important assumption forms part of the 
basis of the received theory of thermoelectricity, to prove it was 
one of the main objects of these experiments. 
Very recently, Signor Batelli (Atti della Societd Reale de Torino , 
