248 PROCEEDINGS OP THE AMERICAN ACADEMY 



nitrate a pale, and with mercurous nitrate a bright yellow flocky 

 I^recipitate. 



The first determination of vanadic pentoxide in this salt was made 

 by heat alone, the mixture of molybdic and vanadic oxides being 

 ignited until a constant weight was obtained. In the second analysis 

 the determination was made by titrition with ferrous sulphate after 

 adding chlorhydric acid to the solution. 



Eighteen Atom Series. — A boiling solution of ammonic meta- 

 vanadate readily dissolves molybdic teroxide, M0O3, forming a deep 

 yellow or orange-yellow solution. When the oxide is added as long 

 as it is readily dissolved, an olive-green liquid is obtained, from which 

 after twenty-four hours hard tabular crystals of a pale greenish color 

 are deposited. These crystals are decomposed by boiling water, beau- 

 tiful yellow needles very slightly soluble in water, being formed, to- 

 gether with a greenish yellow solution which soon becomes turbid. 

 The salt could not be purified by recrystallization, and was therefore 

 washed with a little cold water and dried on woollen paper. Of this 

 salt, — 



0.8067 gr, ignited with WO.Na, lost 0.1586 gr. = 19.66% 

 0.8538 gr. gave 0.2140 gr. NII^CI =12.18% (NHJP 



1.0243 gr. " 0.2526 gr. " =11.99% " 



0.7945 gr. " 0.0407 gr. V^O^ = 5.12% 



These analyses correspond to the formula 



18 M0O3 . V2O5 . 8 (NH,X,0 + 15 aq. 



3461 100.00 



A more extended investigation will, undoubtedly, show that the 

 vanadio-molybdates are, to say the least, numerous. The salts which 

 I have described are sufficient to establish a parallelism between them 

 and the phospho-molybdates, which is the more interesting because 

 the chemical relations of vanadium are nearer to antimony than to 

 phosphorus and arsenic. I shall return to this point, however, in 

 describing and discussin"; the class of antimonio-tunijstates and anti- 

 monio-molybdates. 



