Dr. Muspratt on the Salts of Sulphurous Acid. 419 



The copper has also been determined in the salt by my 

 brother Frederick and myself. 



F. M. 6-94 grs. salt gave 4-70 CuO = 4-22 Cu20 = 60-8o' 



Dr. M. 11 -41 7-48 CuO = 6-72 Cu20 = 58-88 



It is evident from the preceding results, that if the base of 



this salt be onhj suboxide of copper, its constitution may be 



assumed as the following, — 



CU2O, SOa + aq. 



Dr. Rammelsberg found the annexed quantities of sulphurous 

 acid, — 



35-12 35-06 34-47, 

 which I can only account for by his salt not being so well 

 washed as mine. My salt dissolves in hydrochloric acid, af- 

 fording a colourless liquid, and when a weak solution of pot- 

 ash is added to this, a white precipitate subsides. Yellow 

 prussiate of potash gives a whitish precipitate in the acid so- 

 lution, soluble in an excess of muriatic acid. When the red 

 salt is placed on a filter and affused with boiling water until 

 the filtrate affords no milkiness with barytes, half of its sul- 

 phurous acid is removed. 



7-37 grs, gave 4-41 grs. BaO, 803= 1-21 S02= 16-41 per cent. 

 This quantity favours the formula — 



2(Cu20, HO) SO2. 

 Bottinger states in his paper, " That by long boiling with 

 the liquid this salt loses sulphurous acid and becomes lighter 

 in colour, which confirms my own observation. The analy- 

 sis of such a precipitate gave me 66-60 per cent, of CuaO, 

 which will account for the varying results obtained by dif- 

 ferent chemists when analysing this red salt.'^ 



Sulphite of Copper and Soda. — When rather strong solu- 

 tions of sulphate of copper and sulphite of soda are mixed 

 together and treated with absolute alcohol, a dark reddish- 

 looking liquid, which greatly resembles nitrobenzide, sub- 

 sides, and if this be collected and left in vacuo for some time, 

 fine yellow crystals appear, which after washing and desicca- 

 tion afforded the subjoined results : — 



Per cent. 

 16-40 grs. salt gave 7"27 grs, HO =44-32 



15-17 1-81 ... CuO =1-62 Cu20 = 10-67 



6-13 5-44 ... BaO, 803=1-49 SO2 =24-30 



These numbers agree very closely with the formula — 

 CujO, 802 + 5(NaO, S02) + 38aq, 

 if there was no uncombined sulphite of soda present. 

 2 F2 



