84 PROCEEDINGS OF THE AMERICAN ACADEMY 



crystals are formed which do not contam zinc, and whicli may be re- 

 crystallized without apparent decomposition. The salt dissolves in a 

 large quantity of water to a colorless solution. It is only partially de- 

 composed by boiling with mercurous nitrate. In this compound, 



0.7105 gr. gave 0.0326 gr. (NHJjO = 4.58% 

 0.9785 gr. " 0.0455 gr. " = 4.65% 

 1.2612 gr. " 1.3720 gr. MoO^Ba = 52.74% M0O3 

 1.3081 gr. « 0.3856 gr. AsoOg = 29.48% 

 0.6044 gr. » 0.1787 gr. " =29.55% 



The analyses correspond fairly well with the formula 



12 M0O3 . 5 AsoO. . 3 (NH4)20 + 24 aq, 



which requires : 



- 82.24 



3306 lUO.OO 



The reactions of this salt were studied by acting with metallic solu- 

 tions upon the finely pulverized substance, so as to avoid, if possible, 

 the decomposing action of water. In this manner cold solutions of 

 argentic and thallous nitrates give beautiful colorless granular crystals. 

 Baric chloride gives a white colorless salt more flocky than the am- 

 monium compound. Manganous sulphate does not react in the cold, 

 but on boiling for some time a beautiful pale canary-yellow crystalline 

 salt is formed. Cupric sulphate does not act when cold, but on boiling 

 a clear solution results. 



6 : 3 Arsenoso-mohjbdate of Manganese. — A portion of the dry 

 gummy mass of arsenoso-molybdate of ammonium, which had stood 

 for some time in the laboratory, was redissolved and filtered from a 

 small quantity of arsenous oxide. The filtrate gave no precipitate 

 with manganous sulphate, but, on boiling, the fine green solution be- 

 came much lighter in color, then turbid, and finally deposited very 

 beautiful bright orange-colored octahedral crystals insoluble in water. 

 Of this salt, 



0.5961 gr. gave 0.2052 gr. As,03 = 34.41 % 



0.7341 gr. -' 0.1216 gr. PaO-Mnj = 8.28% MnO 



0.6362 gr. lost on heating over a radiator 0.0428 gr. = 6.73% 



