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, W0 4 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, — 



0.7356 gr. gave 0.6992 gr. W0 3 + P 2 5 = 95.05% 



0.7356 gr. " 0.0390 gr. P 2 O.Mg a = 3.39% P 2 5 



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



The phosphoric acid was twice precipitated. The analyses lead to 

 the formula 



16 W0 3 . P 2 5 . CaO . 5 H 2 + 3 aq, 

 which requires : — 



salt to which Scheibler gave provisionally the formula 

 Na 5 H u W 6 P,0 31 -J- .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. WO, -4- P 2 5 = 83.46% 



2.1547 gr. " 0.1005 gr. P 2 7 Mg 2 " = 2.98% P 2 O s 



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



The analyses give the formula 



16 W0 3 . P 2 5 . 4 K 2 . 2 H 2 -f- 19 aq, 

 or, 



W 16 P 2 47 (KO) s (HO) 4 +19aq, 



