222 THE ATOMIC WEIGHTS. 



reeled syntheses gave Sb = 120.295. In these eleven experiments the 

 following percentages of S in Sb a S 3 were established : 



28.57 

 28.60 

 28.57 

 28.43 

 28.42 



28.53 

 28.50 

 28.49 

 28.58 

 28.50 

 28.51 



Mean, 28.5182, =b .0120 



These results, confirmatory of the work of Schneider, were presented 

 to the American Academy in 1876. Still, before publication, Cooke 

 thought it best to repeat the work of Dumas, in order to detect the cause 

 of the old discrepancy between the values Sb = 120 and Sb = 122. Ac- 

 cordingly, various samples of antimony trichloride were taken, and puri- 

 fied by repeated distillations. The final distillate was further subjected 

 to several recrystallizations from the fused state ; or, in one case, from a 

 saturated solution in a bisulphide of carbon. The portions analyzed 

 were dissolved in concentrated aqueous tartaric acid, and precipitated 

 by silver nitrate, many precautions being observed. The silver chloride 

 was collected by reverse filtration, and dried at temperatures from 110 

 to 120. In one experiment the antimony was first removed by H 2 S. 

 Seventeen experiments were made, giving, if Ag = 108 and Cl = 35.5. a 

 mean value of Sb = 121.94. If we reduce to a common standard, Cooke's 

 analyses give, as proportional to 100 parts of AgCl, the quantities of SbCl s 

 stated in the third column : 



i.5974grm. SbCl 3 gave 3.0124 grm. AgCl. 53.028 



1.2533 " 2.3620 " 53.061 



.8876 1.6754 52.978 



.8336 i 5 6 74 53-^4 



.5326 " i. 0021 " 53-H8 



.7270 " i.3 6 9 T " 53- T i 



1.2679 " 2.3883 " 53.088 



1.9422 3.6646 52.999 



1-7702 " 3-3384 " 53.025 



2.5030 4-7184 53.048 



2.1450 " 4.0410 " 53.081 



1.7697 " 3.3281 " 53.175 



2-3435 4.4157 53.072 



1.3686 " 2.5813 " 53-O2O 



1.8638 " 3-5'46 " 53.03 



2.0300 " 3.8282 " 53.028 



2.4450 " 4.6086 53.053 



Mean, 53 066, zfc .0096 



