OF ARTS AND SCIENCES. 113 



portion changes its character, and is converted into a soft crystalline, 

 very slightly soluble mass. This may be filtered oif, and washed with 

 cold water. In this salt, 



( 1.5236 gr. lost on ignition 0.0857 gr. = 5.G3% 

 I 1.5236 gr. gave 0.0517 gr. Pp^Mg^ = 1.96% Pp^ 

 0.9934 gr. " 0.0303 gr. " = 2.17% " 



1.0686 gr. " 0.0352 gr. " = 2.11% " 



( 1.1490 gr. " 1.0171 gr. oxides =88.52% 

 1 1.1490 gr. " 0.3327 gr. PtCl^Ka = 5.70% K.^0 



The analyses correspond very well to the formula 

 24 WO3 . 2 {PO3K} 3 K2O + 20 aq, 

 which requires : 



6446 100.00 



The filtrate from the 24 : 2 salt, on standing, deposits a white crys- 

 talline salt, which, when thrown on a filter and washed with cold 

 water, presents a colorless gummy mass. Of this salt, 



0.6183 gr. gave 0.0307 gr. PjO^Mgo = 3.17% P2O5 

 j 0.8173 gr. " 0.6844 gr. oxides = 83.72% 

 \ 0.8173 gr. lost on ignition 0.0607 gr. = 7.43% 



From an oversight, the potassic oxide was not determined in this 

 salt, which may be either 



16 WO3 . 2 {PO3K} 2 K.,0 . 2 NagO + 20 aq, 

 or 



16 WO3 . 2 {PO3K} 5 NaaO + 20 aq. 



The formulas require, respectively, 



Calc'd. Found. 



16 WO3 3712 80.34 80.56 



P2O. 142 3.07 3.17 



3K2O 283 6.12)33, 337 



2 NaoO 124 2.68 ^ 



20 H2O 360 7.79 7.40 



4621 100.00 100.00 4618 



VOL. XXI. (N.S. XIII.) 8 



