OF ARTS AND SCIENCES. 117 



Found. 



3.19 



2146 100.00 



The formula may be more advantageously written 



10 M0O3 . 4 {PO3NH,} . 3 (NH4)oO + 9 aq. 



Empirically, this salt has, except as regax'ds water of crystalliza- 

 tion, the same formula as the acid 10 : 2 orthophospho-molybdate, 

 which I have already described. 



HEXAMETAPHOSPHO-MOLYBDATES. 



The single salt of this series which I have thus far obtained will 

 serve as an example, and I hope as an incentive to further study. 



14:3:4 Baric Hexametaphospho-mohjbdate. — Sodic hexametaphos- 

 phate, obtained by heating the so-called microcosmic salt until a clear 

 colorless glass is obtained, gives a white colorless crystalline salt with 

 baric chloride, which, after washing with cold water, readily dissolves 

 in an excess of a solution of 14 : 6 ammonic molybdate. After a short 

 time the clear filtered solution deposits an abundance of beautiful 

 colorless acicular crystals. This salt cannot be perfectly decomposed 

 by boiling with a solution of mercurous nitrate. Nitric acid dissolves 

 it to a turbid liquid, with formation of a yellow powder. After boil- 

 ing with the acid, ammonic molybdate gives the characteristic yellow 

 crystalline precipitate, indicating the presence of orthophosphoric acid. 

 Of this salt, 



1.0140 gr. lost on ignition with WOiNag 0.2463 gr. = 24.31% 

 1.8970 gr. gave 0.4286 gr. SO^Ba = 14.84% BaO 



2.0103 gr. " 0.3454 gr. PoO.Mgo = 10.83% P2O5. 



The formula appears to be 



14 M0O3 . 3 PgOg . 4 BaO + 55 aq, 

 which requires : 



