514 Messrs. Playfair and Joule on 



,„, f,4,,,S>BiO,JNO;„ vol. of salt 55-6 ... 5-241 



tf;."l|r' T ■ ... ... 55;2 ... 5'279 



Mean . . 55-4 ... 5-260 Ci;t>-S bnu 



Suhnitrate of Mercurij, HgO, NO^ HO + 2HgO = 39l4^. 

 — ^I'his salt was obtained in a yellow powder by adding the 

 crystallized subnitrate of mercury to water, and Avashing it, 

 according to the directions of Kane, with hot, but not boiling 

 water. The fourth part of an equivalent, 97'87 grains, thrown 

 into turpentine, caused an increase of 16-4, which gives 65-6 

 as the atomic volume of the salt, and 5-967 as the specific 

 gravity, 



Ammoniacal Sulphate of Copper, CuO, SOg HO, + 2NH3= 

 123-0. — This salt has already been described in a previous 

 section ; it had a volume of 54-0 or 9 x 6 in a state of solu- 

 tion, and of 68-6 or 9-8 X 7 in the solid state. The salt exa-^^ 

 mined in that case was in fine large indigo blue crystals, and 

 was prepared by ourselves. Another portion, made by Mr. 

 Morson in small crystals, we found to possess a volume of 

 68-0 and specific gravity of 1-809. When this salt is heated 

 it loses one equivalent of water and one of ammonia, being 

 converted into a green powder, the formula of which is CuO, 

 SOg 4- NHg ; 24-27 grains of this, thrown into turpentine, 

 caused an increase of 9'8, which gives 39-2 as the volume of 

 the equivalent, and 2*476 as the specific gravity of the salt. 

 The latter salt on being moistened with water absorbs three 

 equivalents, and therefore assumes the atomic weight of 

 124*07; the fourth part of which, 31-0 grains, thrown into 

 turpentine, caused an increase of 15*9, making the atomic 

 volume of CuO, SOg + NHg + 3HO, G^'Q, and its specific 

 gravity 1*950. 



Ammonia- Sulphate qf Zinc. — Kane describes several am- 

 monia-sulphates of zinc, obtained by passing a stream of am- 

 monia through a hot solution of sulphate of zinc, until the 

 precipitate at first formed is redissolved. The solution thus 

 obtained deposited transparent crystals in a few hours, but 

 these effloresced so quickly after being dried, that we did not 

 determine their specific gravity. The effloresced crystals 

 have, according to Kane, the formula — 



ZnO, SOg + 2 NHg -}- 2 HO = 132-8. 



We fear, however, that we have not been successful in pro- 

 curing this salt in its proper state, as the determination of its 

 volume varied between 57*5 and 640, results so discordant, 

 that it would not be safe to take their mean as a correct re- 

 sult. On heating this salt it loses water and ammonia, being 



