I 



170 THE ATOMIC WEIGHTS. 



A7. - Co. 



3-398 ^ 3.404 ) , , 



11 - ^ 3u sample. 



3.409 V 2d sample. 3-405 J 



3-404 J 3-4IO ^ 



, , y 4th sample. 



3.401 —3d sample. 3.407/^ 



3-412 I 



3.408 ►4th sample. Mean of all, 3.4017, ±.0009 

 3.410 i 



Mean of all, 3.41 1, i .001 



A glance at the tabulated discussion which closes this 

 chapter will show that these figures agree well with each 

 other, and well with those found from the analyses of the 

 oxides. The probable errors assigned in the hydrogen 

 series may be a little too low, since they ought to be modi- 

 fied by the probable error of the weight of a unit volume 

 of hydrogen. So insignificant a correction may, however, 

 be neglected. 



Some time after the publication of Russell's first paper, 

 but before the appearance of his second, some other investi- 

 gations were made known. Of these the first was by Som- 

 maruga,* whose results, obtained by novel methods, closely 

 confirmed those of Schneider and antagonized those of Du- 

 mas, Marignac, and Russell. The atomic weight of nickel 

 Sommaruga deduced from analyses of the nickel potassium 

 sulphate, K,Ni(SO Jo.6H,0, which, dried at 100°, has a 

 perfectly definite composition. In this salt the sulphuric 

 acid was determined in the usual way as barium sulphate, 

 a process to which there are obvious objections. In the 

 third column are given the quantities of the nickel salt pro- 

 portional to 100 parts of BaSO^ : 



*Sitzungsb. Wien Akad., 54, 2 Abtli., 50. 



1866. 



