OP ARTS AND SCIENCES. 125 



1.5911 I lost on I 0.1470 

 0.9086 I ignition I 0.0837 

 1.0934 J [ 0.1009 J 



Gr. Gr. Perct. Per ct. 



0.8697] [ 0.0805] [ = 9.26 = 90.73 W0 3 -|-P 2 6 



water and I = 9.24 = 90.76 " 



ammonia I =9.21 = 90.79 « 



1=9.21 = 90.79 " 



( 1.0934 gave 0.0439 P 2 7 Mg 2 = 2.63 P 2 0. 



1.7970 " 0.0993 NH 4 C1 " = 2.68(NH 4 ) 2 



These analyses correspond very closely to the formula, 



22 W0 3 . P 2 5 . 3 (NHJ 2 . 3 H 2 -f 18 aq, 



which requires : — 



Calc'd. Mean. 



22W0 3 5104 88.30 88.29 88.25 88.28 88.31 88.31 



P 2 5 142 2.46 2.48 2.48 corr .' 



3 (NHJ 2 156 2.69 2.68 2.68 



21H 2 _378 6.55 6.60 6.58 6.56 6.53 6.53 



5780 100.00 100.05 



22 : 2 Sodium Salt. — It has already been mentioned that, in the 

 preparation of the acid sodium salt of the 24-atom series, a white very 

 slightly soluble crystalline powder is formed in greater or less quantity. 

 This salt cannot be recrystallized for analysis, and must therefore be 

 washed with cold water to remove traces of the soluble acid salt. Hot 

 water dissolves it in small proportion only, the solution remaining milky 

 for a long time. In one preparation of this salt, — 



( 0.8405 gr. gave 0.7962 gr. W0 3 + P„0 5 = 94.73% 



( 0.8405 gr. « 0.0330 gr. P 2 17 Mg 2 " = 2.51$ {^XdjI^A 



1.4990 gr. lost on ignition 0.0403 gr. water = 2.69% 



These analyses lead to the formula 



22 W0 3 . P 2 5 . 2 Na 2 . 4 H 2 + 5 aq. 



Calc'd. 



22 : 4 Barium Salt. — This salt was obtained by mixing neutral 

 sodic tungstate and hydro-disodic phosphate in the proportion of 24 : 2, 

 neutralizing with acetic acid, and adding a solution of baric chloride. 

 Small sharp prismatic crystals formed after a short time, soluble in hot 



