130 THE ATOMIC WEIGHTS. 



Schneider himself effected the combustion of manganous 

 oxalate with oxide of copper. The salt was not absolutely 

 dry, so that it was necessary to collect both water and car- 

 bon dioxide. Then, upon deducting the weight of water 

 from that of the original material, the weight of anhydrous 

 oxalate was easily ascertained. Subtracting from this the 

 CO 2, we get the weight of Mn. If we put CO 2 = 100, the 

 quantities of manganese equivalent to it will be found in 

 the last column : 



1.5075 grm. oxalate gave .306 grm. Hfi and .7445 grm. CO.j. 61.3835 



2.253 " .4555 " I.I135 " 61.4291 



3.1935 " .652 " 1.5745 " 61.4163 



5.073 " 1.028 " 2.507 " 61.3482 



Mean, 61.3943,^.0122 



Hence Mn = 53.904, ± .014. 



This result agrees beautifully with the value calculated 

 from Rawack's experiments. 



Now to combine the four independent values which we 

 have thus far obtained : 



From MnCl, Mn = 54.858, ± .031 



" MnSO^ " =54.785,^.031 



" MhoP^ " = 53.911, d= i026 



" MnC20^ " =53.904,^.014 



General mean " =54.128,^.011 



If 0=16 " =54.251 



The considerations already cited, however, go to show 

 that this general mean must be slightly affected by some 

 plus constant error. It is probable, therefore, that a more 

 correct jfigure will result from rcyecting the first and second 

 values in the above combination, and taking the data fur- 

 nished by Rawack and Schneider alone. Combining their 

 figures, we get as follows. Mn = 53.906, ± .012. Or, if 

 = 16, Mn = 54.029. 



Since the foregoing calculations were made Dewar and 

 Scott* have reported the following experiments. From the 



* Nature, Sept. 15, 1881, p. 470. 



