268 PROCEEDINGS OF THE AMERICAN ACADEMY 



The solution of this salt had a deep orange-red color with distinct 

 greenish reflections. Bromine water instantly gave a very fine deep 

 orange solution, having nearly the color of jaotassic dichromate, and 

 without the greenish tint : the liquid then contained only a sodic vana- 

 dio-tungstate. The solution gave flocky precipitates with various salts 

 of heavy metallic oxides, and a bright red crystalline precipitate with 

 argentic nitrate. A solution of acid potassic tungstate dissolved the 

 mixture of oxides of vanadium, forming a greenish-orange solution, 

 which also became bright orange-red with bromine. The potassic salt 

 crystallized from this solution after evaporation to the consistency of a 

 syrup, and gave crystals of a peculiar greenish-orange tint. The solu- 

 tion of this salt gave a bright orange indistinctly crystalline precipitate 

 with mercurous nitrate. This precipitate was decomposed by dilute 

 chlorhydric acid, yielding a yellow solution from which no crystals were 

 obtained by evaporation. This is perhaps the acid of the series. 



12 : 2 : 3 (?) Ammonium Salt. — 12:5 acid ammonic tungstate 

 was boiled with a portion of the same commercial vanadic oxides in 

 excess. The oxides dissolved readily, leaving, as in the cases of the 

 sodium and potassium salts, a quantity of a black insoluble powder. 

 The deep orange-yellow solution deposited on cooling beautiful orange- 

 colored crystals of an ammonium salt ; but on evaporating the main 

 solution in vacuo, two kinds of crystals were obtained, one in relatively 

 large dark-red octahedrons, the other much lighter-colored and resem- 

 bling potassic dichromate. The darker salt gave in two analyses 17.98 

 and 18.05 f)^ of water and ammonic oxide. Of the lighter-colored salt 

 separated mechanically from the first-named, — 



0.8429 gr. lost on ignition 0.1149 gr. = 13.63% H^OandNHg 



0.81G4gr. " " 0.1107 gr. =13.56% " " 



0.9047 gr. gave 0.1502 gr. NH.Cl = 8.07% (NH,)20 



The analyses agree, so far as they go, very well with the formula, 



12 WO3 . 2 Yfi, . 3 VO2 . 6 (NHJ^O + 12 aq, 



which requires : — 



3927 100.00 



