OXYGEN, 33 



based upon the density of the mixed gases obtained by the electrolysis 

 of water, gave 2.0037 ; but Morley shows that some corrections Avere 

 neglected. This determination, therefore, may be left out of account. 

 Now, including all data, we have a mean value for the density ratio : 



(A.) H :0: : I : 15.S948, ± .00048; 



or, omitting Morley's rejected series, 



(B.) H :0: : I : 15.8991, ± .00048. 



' Correcting these by the volume ratio, 2.0028, ± .00004, the final result 

 for the atomic weight of oxygen as determined by gaseous densities 

 becomes : 



From A O =^ 15.8726, ±z .00058 



From B O = 15.8769, ± .00058 



Combining these Avith the result obtained from the s^'ntheses of water, 

 rejecting nothing, we have — 



By synthesis of water O := 15.8837, zb .00026 



By gaseous densities O = 15.8726, ± .09058 



General mean O ;= 15.8821, zfc .00024 



If we reject Reiser's work under the first heading, and omit Morley's 

 defective hydrogen series under the second, we get — 



By synthesis of water O ^ 15.8796, zt .00027 



By gaseous densities O := 15.8769, ± .00058 



General mean O = 15.8794, dr .00025 



Morley, discussing his own data, gets a final value of = 15.8790, ± 

 .00026, a result sensibl}^ identical with the second of the means given 

 above. These results cannot be far from the truth ; and accordingly, 

 rounding off the last decimals, the value 



= 15.879, ±.0003, 

 will be used in computation throughout this work. 



Note. — A useful " short bibliography " upon the composition of water, 

 by T. C. Warrington, may be found in the Chemical News, vol. 73, pp. 

 137, 145, 156, 170, and 184. 



