62 Scientific Intelligence. [July, 



black oxide refuses to combine witb sulphurous acid. When 

 the two substances come in contact, the black oxide gives out 

 half its oxygen, and by this means is changed into red oxide, 

 while a portion of the sulphurous acid is changed into sulphuric 

 acid. 



Sulphite of copper is of a red colour, and crystallizes. It 

 may be obtained by mixing sulphite of potash and sulphate of 

 copper together, or by passing a current of sulphurous acid gas 

 through water, in which black oxide of copper is suspended. It 

 is decomposed by heat, and by boiling in water. According to 

 the experiments of Chevreul, it is composed of 



Red oxide of copper 63*84 



Sulphurous acid 36" 16 



100 



■ 



But this analysis cannot be accurate. It gives us 100 acid + 

 176-549 oxide. Now the weight of an integrant particle of 

 sulphurous acid is 4, and of red oxide of copper 9. Hence if 

 the two substances unite particle to particle, the compound must 

 consist of 100 acid -f- 225 oxide. We learn from the experi- 

 ments of Berzelius that sulphuric and sulphurous acids unite 

 with the same weight of base. Now according to him 100 

 sulphuric acid unite with 1S3 of red oxide of copper. (Ann. de 

 Chim. Ixxvii. 83.) Hence 80 sulphurous acid would unite with 

 183 red oxide. This gives us 100 acid + 22S'75 red oxide, 

 which agrees very nearly with an atom of acid and an atom of 

 oxide. Hence I conceive it to be indisputably much nearer the 

 truth than Chevreurs analysis. The reader will find Chevreul's 

 experiments in the Ann. de Chim. vol. lxxxiii. p. 181. 



Chevreul obtained likewise a triple salt, composed of sul- 

 phurous acid, potash, and red oxide of copper. He procured it 

 by mixing a cold solution of sulphite of potash with nitrate of 

 copper. The triple salt precipitated of a yellow colour. Ac- 

 cording to his analysis, it is composed of 



Red oxide 0-9360 



Potash 0-1556 



Acid 0-6270 



1-7186 



This analysis would stand in need of some animadversions; 

 but they would not be understood till we have come, in our 

 table of the weight of integrant particles of chemical compounds, 

 to the triple salts. We shall therefore defer the subject at 



present. 



