{ 190 ) 



assuming a value for l>,.. If we assume 0,0024, a value which lies 

 between &,= 0,0020 and i„ — 0,0029, while an error in this value 

 will have comparatively little influence on the value of «,2, we find 



a,, = 0,7 X 0,0036 X 'A + 0,00328 = 0,010 . 



From Mr. Kuenen's values for the variation of pressure (— A;)), 

 we find the following value for 0,3, which has been calculated by 

 means of the approximative equation. 



For the calculation of Oj„ from the results at v = 0,01.5, given 

 by Mr. Kuenen, the approximative equation is no longer sufficiently 

 accurate. 



For these values of a, 5 we see the same not yet explained phe- 

 nomenon, generally observed for the values of «, and a„. namely 

 that thev increase at lower temperatures. The advantage of the 

 equation which has served to calculate them, is that it is indepen- 

 dent of possible changes, which might have occurred in the values 

 of a, and n^ through change of temperature. So the accurate deter- 

 mination of — hp is as vet the best means of supplying at least 

 one relation between a,, and i,„. The variability of «,5 with the 

 temperature, would therefore be no reason to doubt of the values 

 found for «,„. There is, however, another circumstance, which makes 



