1893.] 



On the Densities of the Principal Gases. 



147 



Air. Oxygen. Nitrogen. 



2-37512 2-62534 2-30883 



and these may now be compared with the water contents of the 

 globe, viz., 1836-52. 



The densities of the various gases under standard conditions, 

 referred to that of distilled water at 4°, are thus : — 



Air. Oxygen. Nitrogen. 



0-00129327 0-00142952 0-00125718 



With regard to hydrogen, we may calculate its density by means of 

 the ratio of densities of oxygen and hydrogen formerly given by me, 

 viz., 15-882. Hence 



Hydrogen. 



0-000090009. 



The following table shows the results arrived at by various 

 experimenters. Von Jolly did not examine hydrogen. The num- 

 bers are multiplied by 1000 so as to exhibit the weights in grams per 

 litre : — 



Yon Jolly, 1880 



Leduc, 1891* 



Eayleigh, 1893 



Air. 



Oxygen. 



Nitrogen. 



Hydrogen. 



1 -29319 

 1 -29349 

 1 -29351 

 1 -29383 

 1 -29330 

 1 -29327 



1 -42980 

 1 -43011 

 1 -42939 

 1 -42971 

 1 -42910 

 1 -42952 



1 -25617 

 1 -25647 

 1 -25787 

 1 -25819 

 1 -25709 

 1 -25718 



-08958 

 -08988 



-08985 

 -09001 



The correction of Regnault by Craftsf represents allowance for the 

 contraction of Regnault's globe when exhausted, but the data were 

 not obtained from the identical globe used by Regnault. In the fourth 

 row I have introduced a similar correction to the results of von Jolly. 

 This is merely an estimate founded upon the probability that the 

 proportional contraction would be about the same as in my own case 

 and in that of M. Leduc. 



In taking a mean we may omit the uncorrected numbers, and also 

 that obtained by Regnault for nitrogen, as there is reason to suppose 

 that his gas was contaminated with hydrogen. Thus 



Mean Numbers. 

 Air. Oxygen. Nitrogen. Hydrogen. 



1-29347 1-42961 1-25749 0-08991 



* ' Bulletin des Seances de la Societe de Physique.' 

 f -'Comptes Eendus,' vol. 106, p. 1664. 



L 2 



