258 PROCEEDINGS OF THE AMERICAN ACADEMY 



water, but with a large excess of ammonic phospliate it dissolves to a 

 yellow solution ; with ammonia water it gives a colorless solution. In 

 a solution of ammonic carbonate it dissolves with strong effervescence, 

 indicating its distinctly acid character. The salt is not readily reduced 

 by boiling with sulphuric and sulphurous acids, or by citric acid in the 

 presence of chlorhydric acid, but easily by boiling with a strong solu- 

 tion of potassic cyanide, and, as is usual with this class of compounds, 

 by fusion with the same salt. 

 Of this compound, — 



2.0684 gr. lost on ignition with WO.Naj 0.2068 gr. = 10.00% NHg 



and HoO 

 1.0971 gr. gave 0.0747 gr. NH.Cl = 3.31% (NH,)20 

 1.3424 gr. " 0.0568 gr. PjO^Mg = 2.71% }\0. 

 2.5488 gr. " 0.1 102 gr. " =2.77% " 



1.0555gr. " 0.0]23gr. V2O5 =1.10% 



The analyses correspond very closely to the formula, 



60 WO3 . 3 P^Og . Yfi, . 10 (NIIJP + 60 aq, 

 which requires : — 



90.00 



16129 100.00 



The compound is very probably a double salt, and may have the 

 formula, 



3 {16 WO3 . P,0, . 3 (NH,),0} -f- 



12 WO3 . VA . (NH,),0 . 2 HP + 58 aq. 



The arrangement of the constituents is here, of course, purely arbi- 

 trary, and must be regarded as only provisional. In the analyses 

 above given the phosphoric oxide was determined directly and by 

 double precipitation. The vanadic oxide was determined by boiling 

 with chlorhydric acid and titrition, in the manner already described. 



16 : 1 : 3 Series. — A boiling solution of ammonic meta-vanadate 

 dissolves the white insoluble phospho-tungstates of ammonium quite 

 readily to a very deep orange-red solution. After standing some 



