74 PKOCEEDINGS OP THE AMERICAN ACADEMY 



7488 100.00 



The salt is therefore the acid salt corresponding to a neutral salt 

 with the formula 



22 M0O3 . Pp, . 3 K,0. 



Rammelsberg's analyses agree better with the formula of the acid 

 salt given above than with that of the neutral compound assumed by 

 him. 



Twenty Atom Series. — The only salt of this series which I have 

 obtained is one of ammonium prepared like the salts already described, 

 having like these a fine yellow color and a very fine-grained crystalline 

 structure, and like them but slightly soluble in water. Of this salt, — 



1.0936 gr. lost on ignition with WO.Na^ 0.0729 gr. = 6.66% NH, 



and HgO 

 1.8183 gr. lost on ignition with WO^Na^ 0.1155 gr. = 6.35% NHg 



and H^ 

 0.8862 gr. gave 0.6153 gr. Nli.Cl = 4.12% (NH,),0 

 1.3213 gr. gave 0.6224 gr. PA^%2 = 4-19% PA 

 1.5135 gr. gave 0.6349 gr. PaO^Mg,^ = 4.31% PA 



The salt was dried on a water-bath, and afterward over sulphuric 

 acid. The phosphoric oxide was precipitated twice, but not treated 

 with ammonic sulphide. The analyses lead to the formula 



60 MoO„ . 3 PA • 8 (NHJ.O . IToO -f 11 aq. 

 which requires : — 



Calc'd. 



6OM0O3 8640 89.09) gg^g 89.21 1 93 52 



3 P,0- 426 4.39) " 4.31 4.19 i 



8(NHJ,0 416 4.29) ^^^^ 4.12)g.(j 



12 I-ip _216 2.23 ) 2.54) 



9698 100.00 



If we calculate the composition of the mixed oxides of molybdenum 

 and phosphorus existing in this salt we have : — 



