OF ARTS AND SCIENCES. 87 



1.6407 gr. gave 0.113G gr. PaO.Mg, = 5.12% PO3H3 

 1.7G66 gr. " 0.1256 gr. '• = 5.26^^^ 



1.5933 gr. " 0.0791 gr. (NII^),0 = 4.96% 

 1.7340 gr. lost with AVO.Nao 0.2253 gr. = 12.99% 



The analysis is of course subject to the corrections indicated by the 

 equation 



2 POJI3 = P.,0, + OH2 + 4 II. 



The results agree very well with the formula 



22 WO3 . 4 POJL . 6 AnioO + 25 aq, 

 or 



22 WO3 . 4 {H . PO . 2 OH} 6 (NII,),0 + 25 aq, 



which requires: 



6194 100.00 



The phosphorous acid was oxidized by bromine after adding an 

 excess of sodic carbonate. The salt is quietly decomposed by heating, 

 giving a mixture of WO3 . W^O- and PjO^ . 



32 : 16:5 Potassic Phosphoroso-tungstate. — This salt was formed, 

 like tiie ammonium salt, by the action of a mixture of phosphorous and 

 chlorliydric acids upon crystallized 10:4 potassic tungstate. In this 

 case, also, two salts appear to be formed, — a heavier colorless crys- 

 talline salt in relatively large quantity, and a lighter fine-grained 

 salt easily removed by careful washing. Of these, only the first was 

 examined. Of this salt, 



1.4225 gr. gave 1.2124 gr. oxides =85.23% WO.+P.O, 



1.3877 gr. " 0.2428 gr. P,0,Mg,= 11.19% PA= 12.96% PO3II3 



1.3949 gr. lost 0.1406 gr. = 10.08% 



The analyses correspond to the formula 



32 WO3 . 16 PO3H3 . 5 E2O + 46 aq, 

 or 



32 WO3 . 16 {II . PO . 2 Oil} 5 R,0 + 46 aq, 



