92 THE ATOMIC WEIGHTS. 



silver chloride by the usual gravimetric method. Reducing 

 their results to the convenient standard adopted in preced- 

 ing chapters, we have, in a third column, the ciuantities of 

 CsCl equivalent to 100 parts of AgCl : 



1. 8371 gim. CsCl gave 1.5634 grm. AgCl. II7-507 



2.1295 " 1.8111 " 117-580 



2.7018 " 2.2992 " 117-511 



I. 56165 " 1.3302 " 117-399 



Merai, 117.499, ± .025 



Shortly after the results of Johnson and Allen appeared 

 a new series of estimations was published by Bunsen.* His 

 csesium chloride was purified by repeated crystallizations of 

 the chloroplatinate, and the ordinary gravimetric process 

 was employed. The following results represent, respectively, 

 material thrice, four times, and five times purified : 



1.3835 grm. CsCl gave 1.1781 grm. AgCl. Ratio, 117.435 

 1.3682 " 1. 1644 " "7-503 



1.2478 " 1.0623 " 117.462 



Mean, 117.467, =h .013 



Godeffroy's workf was, in its details of manipulation, suf- 

 ficiently described under rubidium. In three of the experi- 

 ments upon caesium the silver chloride was washed by 

 decantation, and in one it was collected upon a filter. The 

 results are subjoined : 



1.5825 grm. CsCl gave 1. 35 1 grm. AgCl. Ratio, 117. 135 



1.3487 " 1.1501 " 117-265 



1. 1880 " 1.0141 '" 117. 148 



1.2309 " I. 051 " 117. 107 



Mean. 117.164, — .023 



We may now combine the three series to form a general 

 mean: 



* Poggend. Annal., 119, I. 1863. 



f Ann. Chem. Pharm., 181, 185. 1876. 



