ATOMIC WEIGHTS 77 



132.734 

 132.754 

 132.724 

 132.729 

 132.741 



Mean, 132.7364, ± .0077 



By Dumas ^ we have the following estimations : 



9.954 Ag gave 13.227 AgCl. Ratio, 132.882 



19.976 " 26.542 " 132.869 



Mean, 132.8755, ± .0044 



Next in order are seven determinations by Stas.^ In the first, second 

 and third, silver was heated in chlorine gas, and the synthesis of silver 

 chloride thus effected directly. In the fourth and fifth silver was dis- 

 solved in nitric acid, and the chloride thrown down by passing hydro- 

 chloric acid gas over the surface of the solution. The whole was then 

 evaporated in the same vessel, and the chloride fused, first in an atmos- 

 phere of hydrochloric acid, and then in a stream of air. The sixth syn- 

 thesis was similar to these, only the nitric solution was precipitated by 

 hydrochloric acid in slight excess, and the chloride thrown down was 

 washed by repeated decantation. All the decanted liquids were after- 

 wards evaporated to dryness, and the trace of chloride thus recovered 

 was estimated in addition to the main mass. The latter was fused in an 

 atmosphere of HCl. The seventli experiment was like the sixth, only 

 ammonium chloride was used instead of hydrochloric acid. From 98.3 

 to 399.7 grammes of silver were used in each experiment, the operations 

 were performed chiefly in the dark, and all weighings were reduced to 

 vacuum. In every case the chloride obtained was beautifully white. 

 Treating Stas' determinations as a single series, his figures are as follows : 



1 Ann. Chem. Pharm., 11.3, 21. 1860. 



2 Oeuvres Completes, 1, 333-341. 



