the Size of Molecules. 697 
of which Maxwell has calculated the coefficients of self- 
diffusion from Loschmidt’s experiments. These are given in 
Lord Kelvin’s Baltimore Lectures *. 
The formula for the coefficient of self-diffusion, corrected 
as explained in the paper following, is 
D=1°34.. 
Pp 
From the four values of D quoted by Lord Kelvin, I have 
calculated the following values for o. 
Values of o deduced from Coefficients of Diffusion. 
Gas. . D. a 
| 
| Pygroren 62. ...0%:: 1-31 2-03 
| D2 32 ees "189 2-71 
| Carbon monoxide... ‘174 2.92 
| Carbon dioxide...... “109 327 
b=27No°. 
In the following table the values of } are taken either from 
Van der Waals’ discussion of Regnault’s experiments, or from 
Rose-Innes’ discussion of Callendar’s experiments. Wherever 
possible, a mean of two sets has been taken :— 
Values of o deduced from deviations from Boyle’s Law. 
Gas. b (mean). «xX 10°. 
eH ydroren at!) 2i 0224. ‘00074 2-05 | 
| Nitrogen «0... 0025 3:12 | 
pakshei de tothe 00203 2.90 | 
| Carbon dioxide...... ‘00228 3°00 | 
| | | 
| 
i 
* Page 295, or Phil. Mag. iv. p. 194. 
