252 PROCEEDINGS OF THE AMERICAN ACADEMY 



yellow solution. After long boiling with an excess of the oxide, the 

 clear deep orange filtrate gives, with a solution of chloride of trimethyl- 

 ammonium, on standing some hours, two distinct kinds of crystals, 

 which are respectively yellow and deep orange-red. There are there- 

 fore, apparently at least, two different salts formed in the solution of the 

 tungstic oxide. The solution of the ammonium salt gave with baric 

 chloride, after some hours, sharp octahedral crystals of a yellow salt but 

 slightly soluble even in hot water. In a second experiment, baric chlo- 

 ride gave at once a yellow fine-grained crystalline insoluble jirecipitate ; 

 but the precipitation was not complete. On boiling the mixture of 

 oxides obtained by igniting amraonic meta-vanadate in air with 12:5 

 sodic tungstate, I obtained a greenish-orange solution. This was oxi- 

 dized by boiling with nitric acid, when it became orange. On standing, 

 the acid solution deposited a relatively large quantity of a sulphur- 

 yellow crystalline body, which was but very slightly soluble in cold 

 water, and required a large quantity of hot water for complete solu- 

 tion. This substance was drained upon the filter-pump, washed with 

 cold water, and dried upon woollen paper. Of this preparation, — 



( 0.8331 gr. lost on ignition 0.1188 gr. = 13.42% 



( 0.8331 gr. gave 0.7192 gr. WO3 -f V^O^ = 86.03% 



0.9786 gr. " 0.8411 gr. " ' =85.95% 



1.0846 gr. « 0.0718 gr. Yfi^ — 6.62% 



The analyses corresi^ond with the formula 



10 WO3 . VA . 6 H,0 + 16 aq, 



which requires : — 



Calc'd. Found. 



IOWO3 2320 80.53] 80.30 U. .. 



VA 183 6.35;^^-^^ 6.62 r^-^^ 



22 H.,0 378 13.12 13.08 



2899 100.00 



I did not succeed in obtaining salts corresponding to the 10: 1 acid 

 above described by saturating the acid with alkaline bases, as mixtures 

 of the acid with alkaline vanadates and tungstates were formed until 

 the point of complete saturation was reached. 



18:1 Vanadio-tungstic Acid. — The orange-yellow mother liquor 

 from which the 12:1 acid separated gave on evaporation beautiful 

 crystalline needles of a second acid, the formula of which is 



18 WO3 . VA . 6 HoO + 30 aq. 



