OF ARTS AND SCIENCES. 127 



formed, which were readily soluble in hot water, and could be recrystal- 

 lized without difficulty. These salts proved to have in all cases the 

 same composition, and are represented by the formula 



20 W0 5 . P 2 0- . 6 BaO + 48 aq, 

 as the following analyses show : — 



I. 

 1.1103 gr. loston ignition with fused borax 0.1458 gr. = 13.14%water. 

 1.1831 gr. " " " " 0.1560 gr. = 13.18% " 



1.0691 gr. gave 0.7775 gr. W0 3 and P 2 5 = 72.72% 



0.9390 gr. " 0.6850 gr. " = 72.84% 



II. 

 1.0676 gr. lost on ignition 0.1400 gr. = 13.11 %water. 



0.6550 gr. gave 0.4763 gr. W0 3 and P 2 5 = 72.72% 



III. 

 1.1110 gr. lost on ignition 0.1461 gr. = 13.15%water. 



0.6409 gr. gave 0.4667 gr. W0 3 and P 2 O s = 72.81 % 



and 0.0704 gr. P 2 O n U 2 = 2.18% P 2 O s 



0.6222 gr. gave 0.0710 gr. P 2 O n U 2 = 



Analyses I. were made with the salt from the 24 to 2 ; 

 obtained from the 12 to 2 ; and III. from the salt of the 

 ture. The phosphoric oxide was precipitated twice. 



70.50 70.62 70.50 



13.14 13.18 13.11 13.15 



hot water, giving a somewhat milky 

 solution. Chlorhydric acid gives no precipitate at first, but after a time 

 a white crystalline powder is formed, which is the acid salt of the 

 24-atom series already described. 



The fact that the same salt is formed independently of the propor- 

 tions of sodic tungstate and phosphate is an important one, and illus- 

 trates the peculiarities of the series of phospho-tungstates which I 

 have already pointed out. 



-Eighteen Atom Series. — When normal sodic tungstate and hydro- 

 disodic phosphate are dissolved together in the proportion of 20 

 molecules of the former to 2 of the latter, and acetic acid is added to 



