130 PROCEEDINGS OF THE AMERICAN ACADEMY 



mother liquor. The crystals are soft and gummy to the touch. I 

 did not succeed in obtaining the salt in a state of purity suitable for 

 analysis. 



Sixteen Atom Series. — The only representatives of this series which 

 I have obtained are salts of calcium, potassium, and ammonium. 

 They are all well defined and more or less distinctly crystalline. 



16:1 Acid Calcium Salt. — When calcic tungstate, WO^Ca, is boiled 

 with a pure dilute solution of phosphoric acid, the salt is dissolved 

 very slowly ; but on addition of a few drops of chlorhydric acid, the 

 tungstate passes quickly into solution. The liquid deposits on evap- 

 oration colorless flat tabular crystals readily soluble in water. Of 

 these crystals, — 

 r 0.7356 gr. gave 0.6992 gr. WO3 -f Vf>^ = 95.05'^ 



1 0.7356 gr. « 0.0390 gr. P^O.Mg^ = 3.39% P2O5 



1.0347 gr. lost on ignition 0.0366 gr. water = 3.54% 



The phosphoric acid was twice precipitated. The analyses lead to 

 the formula 



4054 100.00 



16:4 Acid Potassium Salt. — In the attempt to prepare the sodium 

 salt to which Scheibler gave provisionally the formula 



Na^HiiWgP^Ogi -f 13 aq, 



I obtained a thick sirupy liquid, which on dilution with water gave 

 with potassic bromide, after standing a few hours, beautiful colorless 

 needles. The salt is readily soluble in hot water. After recrystalli- 

 zation, — 



0.5991 gr. gave 0.5000 gr. WO3 + P.O^ = 83.46% 



2.1547 gr. " 0.1005 gr. PA-^^Sa " = 2.98% Vf>^ 



1.0492 gr. lost on ignition 0.0841 gr. water = 8.01% 



The analyses give the formula 



16 WO3 . P2O, . 4 K,0 . 2 H,0 -f- 19 aq, 



W,,P,0„(K0),(H0),4-19aq, 



