126 PROCEEDINGS OF THE AMERICAN ACADEMY 



water apparently without any decomposition, and separating again 

 from the solution in colorless needles. Of this salt, — 



0;6900 gr. gave 0.5494 gr. WO3 -f- Pp. = 79.62% 

 0.6900 gr. « 0.0826 gr. PAiUg = 2.34% P^O^ 



0.6734 gr. " 0.5372 gr. WOg-f P^O^ =79.71% 

 1.5296 gr. " 0.2163 gr. SO.Ba = 9.24% BaO 



0.9682 gr. lost on ignition 0.1076 gr. water = 11.12% 

 0.7064 gr. " " 0.0787 gr. " = 11.14% 



These analyses lead to the formula 



or. 



22 WO3 . P2O5 . 4 BaO . 2 H^ + 39 aq, 

 W22P20o,(Ba02),(HO), + 39 aq. 



77.28 



11.14 



6596 100.00 100.04 



The phosphoric oxide was precipitated twice. 



Twenty Atom Series — The salts of this series closely resemble those 

 which have been described. I did not succeed in preparing the acid, 

 though I made repeated attempts to do so by mixing sodic tungstate 

 and phosphate together in the proportion of 20 molecules of the former 

 to 2 of the latter, neutralizing with nitric acid, precipitating by 

 mercurous nitrate, and decomposing the mercurous salt by dilute chlor- 

 hydric acid. The acid formed always underwent partial decomposition 

 upon concentration, a white crystalline powder being separated while 

 the 24-atom acid was formed. The only well-defined salt of the series 

 which I liave obtained is the normal barium compound. From this it 

 will doubtless be possible to obtain others by double decomposition. 



Normal Id-atom Barium Salt. — As the bai-ic phospho-tungstates 

 crystallize in general much more readily than the corresponding sodic 

 salts, I employed them to determine what compounds are formed 

 when sodic tungstate and phosphate are mixed in various proportions. 

 To solutions of the two salts in the ratios of 24 molecules of the for- 

 mer to 2 of the latter, of 18 to 2, and of 12 to 2, chlorhydric acid was 

 added until the reaction became just distinctly acid. Baric chloride 

 was then added in excess, and the solutions were quickly filtered from 

 the insoluble white precipitate formed. Beautiful colorless crystals 



