OP ARTS AND SCIENCES. 65 



The analyses lead to the formula 



P2O5 . V2O5 . 2 AgP + 5 aq, 



478.6 100.00 



6 : 4 Potassic Phospho-vanadate. — When ammonio-magnesic phos- 

 phate, P20gMg2(NH^)., , is boiled with a strong solution of potassic 

 divanadate, the phosphate disappears and is replaced by yellow granu- 

 lar masses, which are but slightly soluble in water. In this salt, after 

 washing with cold water, 



0.5401 gr. gave 0.3852 gr. P^O^ and V2O5 = 71.31 % 

 0.3790 gr. " 0.1777 gr. V^ with KMnO, = 46.89% 

 0.3790 gr. lost on ignition (alone) 0.0619 gr. = 16.31% 



The analyses lead to the formula 



4 P,05 . 6 V.,0, . 3 K,0 + 2 1 aq, 



Calc'd. Found. 



24.41 ) „, r„ 24 



47 



12.16 



16.25 



^H 71.59 24.42| ^j3^ 



18) 46.80) 



I 28.41 12.38) 28.G9 



) 16.31) 



2327 100.00 



No magnesium and no ammonium could be detected in the salt, and 

 it seems at least probable that the salts of the series might be prepared 

 by the same process, other acid vanadates being substituted for the 

 potassic salt employed. A strong solution in cold water gave a brick- 

 red fine granular precipitate with argentic nitrate, and yellow flocky 

 precipitates with raercurous and thallous nitrates. The mercurous 

 precipitate was distinctly seen to contain two different compounds, and 

 it is therefore probable that tlie potassic salt was decomposed even bj 

 a small quantity of cold water. 



