158 Mr, Faraday on the mutual action of sulphuric acid 



copper acids, &c. This sulphate was collected, washed, dried 

 and weighed. Similar quantities of the carbonate of baryta 

 and oxide of copper were then dissolved in as much of the 

 nitric and muriatic acids as was used in the former experi- 

 ment ; and the washings and other operations being repeated 

 exactly in the same way, the quantity of sulphate of baryta 

 occasioned by the presence of sulphuric acid in the oxide, 

 acids, &c. was determined. This, deducted from the weight 

 afforded in the first experiments, gave the quantity produced 

 from the sulphuric acid actually existing in the salt. Expe- 

 riments so conducted gave very uniform results. The mean 

 of many, indicated 8.9 grains of sulphate of baryta for 10 

 grains of salt used, or 89 grains per cent, equivalent to 

 SO. 17 of sulphuric acid for every 100 of salt decomposed. 



In the analytical experiments, relative to the quantity of 

 carbon and hydrogen contained in the salt, a given weight 

 of the substance being mixed with per-oxide of copper, was 

 heated in a green glass tube. The apparatus used consisted 

 of Mr. Cooper's lamp furnace, with Dr. Prout's mercurial 

 trough ; and all the precautions that could be taken, and 

 which are now well known, were adopted for the purpose of 

 obtaining accurate results. When operated upon in this 

 way, the only substances evolved from the salt, were car- 

 bonic acid and water. As an instance of the results, s-S 

 grains of the salt aflforded 11.74 cubic inches of carbonic acid 

 gas, and 0.9 of a grain of water. The mean of several 

 experiments gave 32.93 cubic inches of carbonic acid gas, 

 and 2.589 grains of water, for every 10 grains of salt 

 decomposed. 



On these data, 100 grains of the salt would yield 329.3 



