526 Messrs. Playfair and Joule on 



"*'^J^'^"W' HgO,NO, + HgO+2HO = 6 vol. 



•''^' HgO, NO5 + HO + 2HgO = 6 .#'J <>SA :t«flJ 

 HgO, NO5 + NH3 + 2HgO = 7 ..: " 

 The first two members of the series have the same number 

 of volumes, because HgO and HO are equivalent, and the 

 last salt should also affect the same, if NHgH = HO. But 

 if we consider the last salt as equal to nitrate of ammonia, in 

 which HgO replaces HO, then it becomes intelUgible. / yiio 

 . i: ' NH^H, HO, NO5 affects 5 + 2 of HO =7 "^^ "i 

 .•ri!.^.NH2H, HgO, NO, ... 5 + 2 of HgO = 7 '* 



On the same principle we would arrange the other ammo- 

 niacal compounds. Thus CuO, SOg + NHg obviously ought 

 to be arranged NH^H, CuO, SO3, corresponding to NH2H, 

 HO, SO3, anhydrous sulphate of ammonia, and both affect, 

 as they should do on this formula, four volumes. We ob- 

 served a very decided peculiarity in sulphate of ammonia ; for 

 while in its hydrated condition the NH4O, SO3 could only be 

 equal to three volumes, in its anhydrous state, or when in com- 

 bination with salts, it assumed four volumes. The latter pe- 

 culiarity attends the alpha ammonia-sulphate of copper, and 

 is shared also by ammonia-sulphate of zinc, while the hydrate 

 assimilates itself to NH4O, SOg-j-HO.xJfnufi oraijg orll Jodftu 



NH.H, HO, SO3 = 39-2 , "" ^r'T^r^"^^^ ^'^^^"^ ^'"^ ^"^''* 

 NH^H, CuO, SO3 = 39-2^''-^^ V^^^.^ ^^'^^ 'iini^nah inoditW 

 NH^H, ZnO, SO3 = 39-2 "' ''•■^^='"^' " ' ' "i ^»•^^- 

 (NH^H, CuO, S03=39'2) + {WC^'^^-^) + (NH3^1^*i=68-6 

 NH2H, HO, SO3 + HO = 44 ^ ^"^'^'- ^' ^'"^' 



(NHgH, CuO, SO3 + HO = 44) + (2HO = 19'6) ^m-^'- 



In ammonia-nitrate of copper we have an instance in which 

 the ammonia may be present either as nitrate of ammonia or 

 as ammonia ; for if we suppose the volume 68'5, which obvi- 

 ously indicates 9*8 x 7 = 68*6, to be made up of CuO, NO, 

 -I- 2NH3, we must assume that two atoms of ammonia are 

 equal to four atoms of ice, for we already have seen that CuO, 

 NO5 affects three volumes. On the supposition that the com- 

 pound contains a substance equivalent to nitrate of ammonia, 

 the volumes are equally intelligible. 



NH2H, HO, NO5 =49'0 



NH^H, CuO, NO5 = 49-0 + NHgH = 19-6 = 68*6 



Perhaps, however, the clearest instances are seen in the 

 ammoniacal chromate and sulphate of silver. AgO, CrOg and 

 AgO, SO3 affect a volume of 9*8 x 3, and supposing a trans- 

 formation into multiples of 11, of which we have seen fre- 

 quent instances, 2NH3=33*0, or NH^slG'S, or 1^ times the 



