{ 



OF ARTS AND SCIENCES. 255 



1.5611 gr. gave 0.1361 gr. NH.Cl = 4.24% (NH,)„0 



1.0113 gr. « 0.0900 gr. " =4.32% "' 



1.3997 gr. " with MuO.K 0.0304 gr. V.Og = 2.17% 



1.9173 gr. " " " 0.0463 gr. " =2.41% 



1.9173 gr. " 0.1112 gr. P.,0-M£r, =3.71c^P.,0. 



o O J J OJ JO J a 



In the last two analyses the vanadic pentoxide was first separated 

 by ammonic nitrate as VOoNIT^ ; the phosphoric oxide was then de- 

 termined in the filtrate. 



The analyses correspond fairly well with the formula 



48 M0O3 . 2 pp. . V,0, . 7 (NHJ.O + 30 aq. 



8283 100.00 



The compound may be regarded as a double salt, with the formula 



2 {16 M0O3 . PA . 2 (NHJ.O . H.,0} + 



1 6 Moa . Vi)^ . 3 (Nil,),© + 28 aq, 



though, of course, other arrangements of the constituents are, in the 

 present state of our knowledge, equally probable. Thus, we may also 

 represent the results of the analyses by the expression, 



2(12 M0O3 . PA • 2 (NHJ2 • H,0} + 



24 M0O3 • ^^P, • 3 (NHJP + 28 aq. 



14: 1 : 8 Series. — The beautiful yellow crystalline phospho-raolyb- 

 dates of ammonium, containing respectively twenty-four and twenty- 

 two molecules of M0O3 to one molecule of i^hosphoric oxide, slowly 

 dissolve when boiled with a solution of ammonic meta-vanadate, giv- 

 ing a very fine deep orange-red liquid. After standing a few hours, 

 the solution gives splendid deep ruby-red crystals in large quantity. 

 These crystals appear to be octahedra ; they dissolve readily in hot 

 water to a de"ep orange-red liquid, without undergoing any apparent 

 decomposition, and the salt crystallizes from the solution unchanged. 

 The solution gives no precipitate at first with baric chloride, but after 

 a time very fine garnet-red crystals are formed in small quantity, mixed 



