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SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 54 



In 1892 Kayleigh published a much more elaborate determination of 

 this ratio.^ The gases were prepared electrolytically from caustic potash, 

 and dried by means of solid potash and phosphorus pentoxide. The 

 hydrogen was previously passed over hot copper. The experiments, 

 stated like the previous series, are in five groups; two for oxygen and 

 three for hydrogen; but for present purposes the similar sets may be 

 regarded as equal in weight, and so discussable together. The weights 

 of equal volumes are as follows: 



Mean, 2.5176, ± .00019 



Mean, .1.5804, 



.000019 



These weights with various corrections relative to temperatures and 

 pressures, and also for the compression of the exhausted globe, ulti- 

 mately become for H, .158531; and for 0, 2.51777. Hence the ratio 

 1 : 15.882, ±.0023. For details relative to corrections the original memoir 

 should be consulted. 



In his paper " On a new method of determining gas densities," ° Cooke 

 gives three measurements for hydrogen, referred to air as unity. They 

 are: 



.06957 



.06951 



.06966 



Mean, .06958, ± .000029 



' Proc. Roy. Soc, 50, 448, Feb. 18, 1892. 



='Proc. Amer. Acad., 24, 202. 1889. Also Am. Chera. Journ., 11, 509. 



