AND RATIO OF THEIR ATOMIC WKIfHITS. 11 1 



But the reduction seems to luive omitted to take into account the deviation 

 of tlie gases fi'oni the hiw of iioyle. If we suppose that the gas wliicL he 

 weighed contained no excess of hydrogen, this vahie would become something like 



2.0024. 



Why the earlier e.vperim.'ents of Scott and myself gave values so much less 

 than these need not be discussed now. Since our later experiments, as well as those 

 of Leduc ^vhen properly reduced, give concordant results, we may have some 

 confidence in them. 



If we combine the ratios of the densities and of the combining volumes 

 obtained in this paper, we get the 



Atomic weight of oxygen ' 5-^79 



The results of my experiments are then as follows : 



Weight of one litre of oxygen, latitude 45° 1.42900 gr. 



Weight of one litre of hydrogen, latitude 45° 089873 gr. 



Atomic weight of oxygen, chemical method 15 879 



Molecular weight of water, chemical method 17-879 



Atomic weight of o.xygen, physical methods 15879 



The last value is subject to correction by further determinations of the 

 volumetric ratio. 



SUMMAEY OF ALL PUBLISHED RESULTS. 



It may be useful to compare the values of the atomic ratio of oxygen and 

 hydrogen, which have been obtained in this paper, with the results of other ex- 

 perimenters. One such value may be computed by combining the ratio of the 

 densities of the two gases, derived from all experiments hitherto published, with 

 the ratio, determined by Scott, of the volumes in which the gases unite. Detei'- 

 minations of the ratio of the densities have been made by Regnatilt,* Rayleigh,t 

 Cooke,J and by Leduc.§ Regnault and Leduc measui-ed volume and pressure at 

 the temperature of melting ice ; the others at the temperature of the laboratory. 

 Cooke weighed hydi'ogen and air, and compared the ratio of theii- densities with 

 the ratio of the densities of air and oxygen, detei-rained by Regnault. The results 



* Mhnoires de V Academic, 21, 143 ; with Comptes Rciidiis, 106, 1662. 

 f Proceedings of the Royal Society, 43, 356 ; 50, 448. 

 \ American Chemical ypiirnal, 11, 537. 

 § Comptes Rendus, 113, 186. 



