184 



THE ATOMIC WEIGHTS. 



studied two compounds of vanadium ; namely, the pent- 

 oxide, V2O5 and the oxy chloride, VOCI3. The pentoxide, 

 absolutely pure, was reduced to V2O3 by heating in hydro- 

 gen, with the following results : 



7-7397 grm. y./\ gave 6.3827 gnn. V^Oj 

 6.5819 " 5-4296 



5.1895 " 4.2819. 



5.0450 " 4.1614 



17.533 P^'' cent, of loss. 



17.507 



17.489 



17-515 



5.4296 grm. V2O3, reoxidized,gave 6.5814 grm. V^Oj. 17.501 percent, difference. 



Mean, 17.509, ^b .005 



Hence V = 51.264, 



.025. 



Upon the oxychloride, VOCI3, two series of experiments 

 were made, one volumetric, the other gravimetric. In the 

 volumetric series the compound was titrated with solutions 

 containing known weights of silver, which had been purified 

 according to the methods recommended by Stas. Roscoe 

 publishes his weighings, and gives percentages deduced 

 from them ; • his figures, reduced to a common standard, 

 make the quantities of VOCI3 given in the third column 

 proportional to 100 parts of silver. He was assisted by two 

 analysts : 



Analyst A. 



Mean, 53.586, zb .039 



The gravimetric series, of course, fixes the ratio between 

 VOCI3 and AgCl. If we put the latter at 100 parts, the 

 proportion of VOCI3 comes out as given in the third 

 column : 



