Atomic Weight of Chlorine, — Hyposulphites. 279 



On the Atomic Weight of Chlorine, Zinc, $c. 



Laurent has made some experiments on the atomic weight 

 of chlorine; the assumption of Berzelius's number agrees 

 completely with the analyses, while considerable differences 

 are visible if the atom be considered as a multiple of that of 

 hydrogen. Marignac determines the atomic weight by pass- 

 ing hydrochloric acid gas over heated oxide of copper ; he 

 finds 225*013, or thirty-six times that of hydrogen. From 

 this he reckons the atomic weight of silver 1374*0, and of 

 potassium 498*5. Jacquelain finds the atomic weight of zinc 

 to be 414. — {Comptes Rendus, Mar. 1842, p. 456; Ibid, 

 Avril 1842, p. 570; Ibid. Mai 1842, p. 636.) 



On the Hyposulphites. 

 Rammelsberg has published an examination of this class of 



salts : the deliquescent potash salt has the formula 3 KS + H. 

 The soda salt contains 5 atoms of water, that with ammonia 

 has the same composition as the potash salt. The baryta salt 

 contains 1 atom of water, that with strontia 5 atoms, with 

 lime and magnesia 6 atoms. A deliquescent double salt of 



magnesia and potassa has the formula K S + Mg S + 6 aq. 

 Hyposulphite of manganese decomposes on evaporation into 

 sulphur and sulphate, the zinc salt the same ; a compound of 

 the zinc salt may be obtained by adding ammonia in excess 

 to a solution of the hyposulphite and precipitating the salt by 



alcohol ; it is Zn S + N H 3 . The nickel and cobalt salts have 

 the same constitution as the magnesia compound ; the nickel 



salt combines with ammonia, and gives (Ni S + 6 H) + 2 N H 3 . 

 Hyposulphite of lead dissolves in solutions of alkaline and 

 earthy hyposulphites, and forms double salts which are easily 

 decomposed. Their solutions must not be heated, for then 

 sulphuret of lead is formed ; they are partly decomposed by 



water. The potassa salt is Pb S + 2 K S + 2 aq, the ammonia 



salt Pb S_+ 2 N H 4 O S + 3 aq. The soda salt has been de- 

 scribed by Lenz {vide the last Report) . Salts may also be form- 

 ed with baryta and strontia; the lime salt is Pb S + 2CaS + 4aq. 

 Hyposulphite of oxide of mercury cannot be obtained ; but by 

 digesting the oxide with solutions of hyposulphites double salts 

 are formed ; the ammonia and potassa salts crystallize, the 



former is HgS + 4 N H 4 OS + 2aq ; the formula of the potassa 



