M. Stas on the Determination of Atomic Weights, 205 



100 parts of silver correspond to 39*356-39-361, mean = 

 39*358 parts of chloride of lithium. Hence if CI = 35 '45 7, 

 Li is = 7022. 



Chloride of lithium was converted into nitrate by evaporation 

 with nitric acid. Owing to the hygroscopic character of the 

 latter salt, the flask for weighing the residue was provided with 

 a chloride-of-calcium tube. The nitrate of lithium, evaporated 

 in the platinum retort with excess of nitric acid, had a feebly al- 

 kaline reaction after being fused in the platinum vessel. The 

 nitrates of potassium and sodium exhibit a similar deportment. 



100 parts Li CI gave 162*588-1 6.2-600, mean 162-595 parts 

 of nitrate of lithium. 



Synthesis of nitrate of silver. — A weighed quantity of the 

 purest silver was dissolved in nitric acid, the solution evaporated, 

 the residue heated almost to fusion in a current of air and again 

 weighed. A repetition of the entire operation, by evaporation 

 with nitric acid, &c, no longer altered the weight of the nitrate 

 of silver. 



100 parts of silver gave 157*494-157*4964 (mean 157*4952), 

 and sharply heated (mean) 157*484 parts of fused nitrate of 

 silver. 



On fusion, nitrate of silver loses a trace of nitric acid. Hence 

 its real weight is between those given above. 



The atomic weight of nitrogen is thus found to be (CI = 35*457) 

 from the ratio 



K CI : K NO 3 = 14*043 



Na CI : Na NO 3 = 14*048 



Li CI: Li NO 3 = 14-046 



Ag CI : Ag NO 3 = 14-044 



Mean .... 14045 



From the synthesis of Ag NO 3 . = 14*041 



= 14*042 



Asa supplement, the author adduces some older and some newer 

 experiments on the relative proportions between bromide of 

 potassium and silver. 



Bromide of potassium was prepared by igniting br ornate of 

 potassium. As ultimately bromine is always given off, the salt 

 was dissolved in water mixed with pure bromide of ammonium, 

 the dry mass heated until all ammonia was expelled, and then 

 fused. Silver was then weighed out in the ratio of the atomic 

 weights Br = 80, Ag= 108, K = 39, precipitated with bromide 

 of potassium, and the excess of silver estimated by a standard 

 solution. 100 parts of silver correspond to 110*361 and 110360 

 parts of bromide of potassium. 



