NITROGEN. LORD RAYLBIGH. 163 



Also, hydrogen only 0.003 from the standard of I 

 exactly. 



But the values of 14.04 (Stas) or the mean of 1882 in 

 Clarke, namely, 14.06 deviate respectively 40 and 60 thou- 

 sandths, instead of only 3 thousandths. 



Hence the value of Stas, namely, N= 14.04, is irrecon- 

 ciliable with the most accurate weighings of pure oxygen 

 and pure nitrogen made up to 1897, by Lord Rayleigh. 



Accordingly, we maintain that these experimental deter- 

 minations of the density of nitrogen, made by Lord Rayleigh 

 in 1897, demonstrate the falsity of Stas* value of 14.04.. 



Density Recognized for Atomic Weight Determination. 



In the edition of the Smithsonian Atomic Weights of 

 1882, the density value falls between the values deduced 

 mainly from Stas' determinations by chemical means and 

 Clarke uses the density determinations ex asquo with the 

 chemical determinations in his mean for nitrogen, as 

 quoted above, p. 160. 



Since the density determinations were much more con- 

 cordant than the vaunted exquisitely and marvelous chemical 

 determinations of Stas, the "probable error " of the density 

 determinations was the smallest of all, only 0.004, while the 

 probable errors of the means of the chemical determinations 

 ran from 15 to 22, or were from 4 to 5 times as large. 



Accordingly, the chemical determinations, namely by 

 Stas, were from 16 to 25 times (the squares of 4 and 5) less 

 reliable, than those obtained from density determinations, 

 according to the valuation of Clarke. 



Therefore the weight of the density determinations being 

 about twenty times as great as the weight of the chemical 

 determinations in the Clarkian sense (we might properly 

 say, in a truly Pickwickian sense), the general mean adopted 

 by Clarke is nearest the density value, and Stas 1 -work is 

 really excluded by Clarke ! 



On page 47 of the edition of 1897, we read concerning 

 determinations made by the most admirable Marignac and 



