124 PROCEEDINGS OF THE AMERICAN ACADEMY 



to an acid which he obtained by the decomposition of a salt of barium, 

 and it may be that this is really the acid of the 22-atom series. 

 Further investigations must decide the point. The salts of the 22- 

 atom series closely resemble those of the 24-atom series already de- 

 scribed, and are only to be distinguished from them by analysis. 

 22 : 2 Putassiam Salt. — The 18-atom potassium salt, 



18 WO3 . P^Oo • ^ l^P + 30 aq, 



gives with chlorhydric or nitric acid a heavy white fine-granular precip- 

 itate of an acid salt which belongs to the 22-atom series, and which has 

 the formula 



22 WO3 . P2O5 . 2 lv,0 . 4 11,0 4- 2 aq, 



as the following analyses show : — 



1.5679 gr. lost on ignition 0.0318 gr. water = 2.03^ 



1.0728 gr. lost on ignition 0.0222 gr. water = 2.07^ 



1.5061 gr. gave 1.4250 gr. WO. + P^O. = 94.61 % 



1.1873 gr. gave 1.1253 gr. WO3 -f Vfi^ = 94.78% 



2.1607 gr. gave 0.0927 gr. Pp.Mg, = 2.74^^ P^O^ 



2.2367 gr. gave 0.0950 gr. Pp^Mgj = 2.72% " 



Calc'd. Mean. 



22WOj 5104 92.08 92.11 92.20 92.03 



P.O^ 142 2.56 2.58 2.59 2.57 corr. 



2 K^o' 189 3.41 3.26 



6 HgO 108 1.95 2.05 2.03 2.07 



5543 100.00 



The salt is very slightly soluble in water. The solution becomes 

 milky, and remains so for a long time. Its formation from the normal 

 18-atom salt may perhaps be expressed by the equation, 



10 (18 WO., . P.O. . 6 K.O) -i- 84 HCl + 36 H^O = 9 (22 WOg . P.,0, . 

 2 K2O . 4' HP) -f 2 (P.,06 . 3 K.,0) 4- 84 KCl + 42 11,0. ' 



22 : 3 Ammonium Salt. — An acid ammonium salt of this series was 

 obtained from a mixture of sodic tungstate and phosphate, to which 

 ammonic nitrate and excess of chlorhydric acid had been added exactly 

 as in tlie preparation of the 24-atom salt already described. The salt 

 was in very small colorless granular crystals, slightly soluble in cold 

 water, but dissolving to some extent in hot water, giving a milky 

 liquid, settling very slowly. Its other properties are not distinguish- 

 able from those of the 24-atom salt. Of this salt, 



