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-atoni series already de- 

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

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



18 W0 3 . P 2 5 . 6 K 2 + 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 WOj . P 2 5 . 2 K 2 . 4 H 2 + 2 aq, 



as the following analyses show : — 



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 W0 3 . P 2 0. 3 . 6 K 2 0) + 84 HC1 + 36 H = 9 (22 W0 3 . P o 5 . 

 2 K 2 . 4 H 2 0) + 2 (P 2 6 . 3 K 2 0) + 84 KC1 -f 42 H 2 0. " 



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

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

 amnionic nitrate and excess of chlorhydric acid had been added exactly 

 as in the 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, 



