ARSENIC. 185 



Analyst A. 



1. 8521 grni. VOClagave 4-5932 grm. AgCl. 40.323 



•7013 " 1-7303 " 40.531 



.74S6 " • 1.S467 " 40.537 



1.4408 " 3.5719 " 40.337 



■9453 " 2.3399 " 40.399 



1. 6183 " 4.02S2 " 40.174 



Analyst B. 

 2.1936 " 5-4039 " 40.391 



2.5054 " 6.2118 " 40.333 



Mean, 40.378, dr .02S 



These two series give us two values for the molecular 

 weight of VOCI3 : 



From the volumetric series VOCI3 = 173.096, zb .126 



" gravimetric " " = 173.276, it .141 



General mean " = 173.177, ± .094 



Hence V = 51.104, ± .104. 



Combining the two values for V we get the following 

 result : 



From VjOj V ^ 51.264, -±z .025 



" VOClg " = 51.104, ± .104 



General mean " ^= 51.256, zb .024 



Or, if = 16, V = 51.373. 



ARSENIC. 



For the determination of the atomic weight of arsenic 

 two compounds have been studied ; the chloride and the 

 trioxide. The bromide may also be considered, since it was 

 analyzed by Wallace in order to establish the atomic weight 

 of bromine. His series, in the light of more recent knowl- 

 edge, may properly be inverted, and applied to the determi- 

 nation of arsenic. 



In 1826, Berzelius* heated arsenic trioxide with sulphur 



* Poggend. Annal., 8, i. 



