266 PROCEEDINGS OF THE AMERICAN ACADEMY. 



We may give this salt the formula 



14 WO3 . 6 Na^O + PAMn3 + 36 aq., 



if we suppose that the pyrophosphate of manganese has become ortho- 

 phosphate. Both constituents are then normal salts. 



The ammonium salt was prepared by double decomposition between 

 the sodium salt and ammonic chloride, and repeated crystallization. 

 It presented orange-colored prismatic crystals, very soluble in both hot 

 and cold water. Of this salt : 



0.7846 gram gave 0.01715 gram NH3 = 2.19%. 

 0.6556 gram gave 0.01394 gram NH3 = 2.13%. 

 0.4886 gram gave 0.0594 gram NH3 + HjO = 12.16%. 

 1.0895 grams gave 0.1162 gram PoOyMn^ = 5.83% MnO. 



The analyses correspond well with the formula, 



28 WO3 . 2 PA • 6 MnO . 5 (NH,)oO . 2 NaoO + 48 aq., 



8364 100.00 

 We may formulate this salt as 



{14 WO3 . 4 MnO . 2 NaoO + P20vMn2} 



+ {14 WO3 . 5 (NH^y.b . HoO -f PAH4} + 45 aq., 



the type being 14 WO3 . 6 RO + P207R'4, so that so far as the em- 

 pirical constitution is concerned the salt may be regarded as a double 

 salt of two normal constituents. The analyses were made by Mr. G. 

 W. Patterson. 



