M. Stasis New Determination of tne Atomic Weights. 141 



converted into carbonate by digestion with ammonia and carbon- 

 ate of ammonia. This carbonate of lead was dried and reduced by 

 cyanide of potassium. Pure lead was also obtained by the reduc- 

 tion of the chloride, either by fusion with cyanide of potassium, 

 or with a mixture of cyanide and black flux. 



The lead was converted into nitrate by heating it with strong 

 nitric acid until it was completely converted into nitrate, and 

 then evaporating to dryness in the same vessel in a current of 

 dry air at 140°. 



100 parts of lead gave 159-974 of nitrate of lead. 



The synthesis of sulphate of lead gave the relation 



Pb : PbO SO 3 =100 : 146-4275. 



The analysis of chlorate of potash, that is, the determination of 

 the quantity of oxygen, was effected either by heating chlorate 

 of potash alone, or by heating it with hydrochloric acid. The 

 first of these methods gave the relation 



KO CIO 5 : KC1 = 100 : 60-8428 ; 

 and the second 



KO CIO 5 : KC1= 100 : 60-849. 



The analysis of sulphate of silver was effected by reduction with 

 hydrogen. 



100 pure sulphate gave 69'203 silver. 



The relations of the atomic weights investigated are seen in 

 the following Table, in which the numbers obtained are com- 

 pared with those which would be required on the hypothesis of 

 Prout :— 



Prout. Stas. 



Ag : CI ... =100: 32-87 =100: 32-8445 



Ag : S ... =100: 14-814 = 100: 14-852 



Ag : AgONO 5 . =100:157-404 = 100:157-473 



Ag : KC1 . . =100: 68-981 = 100: 69-103 



Ag : NaCl . . =100: 54-166 = 100: 54-2078 



Ag : NH 4 C1 . =100: 49-537 = 100: 49-5944 



AgONO 5 : KC1 . . =100: 43-823 = 100: 43-878 



AgO NO 5 : Nil 4 CI . =100: 31-470 = 100: 31-488 



Pb : PbO NO 5 . =100:159-903 = 100:159-969 



Pb : PbO SO 3 . = 100 : 146376= 100 : 146-427 



KOC10 5 :KC1 . . =100: 60816=100: 60-846 



AgOS0 3 :Ag. . . =100: 69-23 =100: 69203 



The following are the atomic weights deduced from Stas's ex- 

 periments as compared with those usually admitted, and taking 

 oxygen at 8 : — 



