418 Dr. Muspratt on the Salts of Sulphurous Acid. 



phite of cadmium. Dr. Rammelsberg analysed a salt which 

 gave him the annexed formula, — 



2(CdO, S02) + NH3. 



Sulphites of Copper. — The brilliant red salt which is formed 

 either by boiling together solutions of sulphate of copper and 

 sulphite of ammonia, or passing sulphurous acid into water, 

 holding in suspension oxide of copper, was first analysed by 

 Chevreul, whose numbers agree with the formula — 



SCu^O, 4S02+5aq. 



I gave the annexed formula for this salt,* — 



CugO, SO^ + aq. 



Bottingert analysed the compound after me, and his results 

 favour the formula — 



SCuaO, 4S03 + 4aq. 



Rammelsberg however has stated that the salt is a double 

 one, and constituted as follows : — 



CuO, SOa+CugO, S02 + 2aq. 

 I have reprepared the red salt by passing a stream of sul- 

 phurous acid into water containing pure oxide of copper. 

 When the whole had dissolved, the liquid was boiled. The 

 red compound deposited in pretty large crystals, which were 

 thrown upon a lilter and etfused with cold water until the fil- 

 trate did not afford the slightest milkiness ivith a solution of 

 chloride of barium. They were then dried in vacuo. I tested 

 the salt for sulphuric acid before submitting it to analysis, 

 and found traces present, even after taking every precaution. 



Analyses. p^,. ^^„j^ 



I. 8-84 grs. gave 9-30 BaO, S03= 2-55 802=28-84 



II. 7-41 ... 8-32 BaO, 803 = 2-28 802 = 30-76 



III. 6-52 ... 7-11 BaO, 803=1-95 802 = 2990 



lA^ 9-62 ... 10-03 BaO, 803=2-759 802=28-68 



V. 18-47 ••• 20-71 BaO, 803 = 5-69 802=30-80 



I. 13-41 grs. salt with PbO, CrOa gave 1-38 H0 = 10-29 



II. 11-13 PbO,Cr03 ... 0-97 H0= 8-71 



III. 10-74 PbO,Cr03 ... 1-02 H0= 9-49 



Mean of the above per cent. 

 Sulphurous acid . . . 29-796 



Water 9*496 



Base or loss 60- 708 



100-000 



* Ann. Chem, und Pharm., bd. 1. p. 285. 

 t Ibid. bd. li. p. 412. 



