ATOMIC WEIGHTS 183 



Series C. 



7.213 grm. SrCL = 9.811 grm. Ag. Ratio. 73.5195 

 2.206 " 3.006 " " 73.3866 



4.268 " 5.816 " " 73.5529 



4.018 " 5.477 " " 73.3613 



Mean, 73.4551 

 Mean of all as one series, 73.4079, ± .0170 



Hence Sr = 87.468. 



The foregoing determinations are now supplanted by the much more 

 recent work of Kichards/ who fused his strontium chloride in a stream of 

 gaseous hydrochloric acid and nitrogen, and adopted all of the precau- 

 tions relative to the solubility of silver chloride which modern experience 

 has shown to be necessary. The results, with vacuum weights, follow : 



Mean, 73.4767, ± .0008 

 Hence Sr = 87.616. 

 Combining this series with the others we have : 



Pelouze 73.4781, ± .0050 



Dumas 73.4079, ± .0170 



Richards 73.4767, ± .0008 



General mean 73.4766, ± .0008 



Dumas' determinations practically vanish, but those of Pelouze are 

 confirmed. 



The foregoing figures apply to anhydrous strontium chloride. The 

 ratio between silver and the crystallized salt, SrClo.6H20, was determined 

 in two series of experiments by Marignac." Five grammes of the salt' 

 were used in each estimation, and, in the second series, the water was 

 also determined. The quantities of the chloride corresponding to 100 

 parts of silver are given in the last column : 



Series A. 



5 grm. SrOL.'OH.O = 4.0515 grm. Ag. Ratio, 123.411 



4.0495 " " 123.472 



4.0505 " " 123.442 



Mean, 123.442 



^ Pioc. Amer. Acad., 40, 603. 1905. Three of the determinations were made by H. G. Parker. 

 ^ Arch. Sci. Phys. Nat., 1, 220. 1858. Journ. prakt. Chem., 74, 216. OeuvTes Completes, 1, 56S. 



