[BOYLE] SOLUTION OF RADIUM EMANATION 111 
In the paper by the writer already referred to, a smoothed curve 
is given showing the variation of the coefficient S with the temperature. 
From it the values of Q given below are calculated, taking T, and T, 
five degrees apart. Calculations are not taken any further than 35°C. 
on account of uncertainties as the end of the curve. 



Heat of Solution 
Temperature approximately calculated 
0° — 5°C 6700  gm-calories 
5 — 10 6300 
10 —T15 5800 (?) 
15 — 20 5600 
20) —25 5500 (?) 
25 — 30 5100 
30 — 35 4700 

The values between 10° and 15° and between 20° and 25° show dis- 
crepancies, the former value being lower and the latter higher than 
would appear to be correct from the sequence of the other numbers; 
but on the whole the numbers proceed regularly and show a relation 
with temperature almost linear. 
From the above it appears that the heat of solution of the emana- 
tion at ordinary temperature is about the same as that found experi- 
mentally for carbon dioxide. Some experimental values for other gases 
at 18° to 20°C. are,— 
Chlorine 4900 
Carbon dioxide 5900 
Hydrofluorie acid 12000 
Hydrochloric acid 17000 
The writer has not yet been able to find corresponding values for the 
inactive monatomic gases, helium, argon, etc., which it would be 
interesting to compare with the emanation. 
The calculated values given above refer only to the heat liberated 
by the process of solution of the emanation as a simple gas, and do not 
consider the heat which would be given to the solution by the expulsion 
of a-particles from the emanation and its products. Compared with 
this the heat liberated in dissolving the emanation is very small. 
