Mr. Henry's Account of Experiments, &c. 189 



should be its complete separation from all other substances, 

 which, by their presence, may tend to introduce uncertainty 

 into the results of the processes that are employed. But it is 

 seldom that a simplicity so desirable can be attained in the ob- 

 jects of chemical research ; for, agreeably to a known law of 

 affinity, the last portions of any substance are separated with 

 peculiar difficulty ; the force of attraction appearing to increase, 

 as we recede from the point of saturation. In a liquid state, the 

 muriatic acid is a totally unfit subject for analytic experiment; 

 for, in the strongest form under which it can be procured, it still 

 contains a large proportion of water. This watery portion, be- 

 sides the complexity which it introduces into the results of 

 experiments, prevents any combustible substance that may be 

 applied, from acting on the truly acid part ; because that class 

 of bodies, having less difficulty in attracting oxygen from the 

 water than from the acid, will necessarily take it from the 

 former source. The state of gas, therefore, is the only one in 

 which the muriatic acid can become a proper object of analysis. 

 In the series of experiments on this gas, which I am now 

 about to describe, I employed the electric fluid, as an agent 

 much preferable to artificial heat. This mode of operating 

 enables us to confine accurately the gases submitted to experi- 

 ment ; the phenomena that occur during the process, may be 

 distinctly observed ; and the comparison of the products, with 

 the original gases, may be instituted with great exactness. 

 The action of the electric fluid itself, as a decomponent, is ex- 

 tremely powerful ; for it is capable of separating from each other, 

 the constituent parts of water, of the nitric and sulphuric acids, 

 of the volatile alkali, of nitrous gas, and of several other 

 bodies, whose components are strongly united. I began, there- 



