14 



and showed marks of putrescence, the light seemed to be more 

 quickly extinguished. In some instances the light was ejected in 

 globules, like quicksilver when rubbed with any unctuous substance, 

 and afterwards adhered to the sides of the vessel in the form of a 

 lucid ring. The serum both of healthy and diseased persons retained 

 the luminous appearance somewhat longer than the crassamentum, 

 and frequently recovered it when agitated. Urine, both fresh and 

 stale, and bile, showed little disposition to retain this light. Lastly, 

 milk and cream, illuminated by mackerel light, acquired great bright- 

 ness, and retained it for upwards of twenty-four hours ; but when 

 either of these turned sour, they contracted a very extinguishing pro- 

 perty, the light in some case vanishing almost instantaneously. 



Account of a Series of Experiments, undertaken with the view of de- 

 composing the Muriatic Acid. By Mr. William Henry. Commu- 

 nicated by the Right Hon. Sir Joseph Banks, Bart. P.R.S. Read 

 Feb. 27, 1800. [Phil. Trans. 1800, p. 188.] 



In the introduction to this paper the author points out the great 

 utility that would accrue to chemical science, were it possible to ar- 

 rive at a complete analysis of certain acids, since the new, and in- 

 deed every system of chemistry, will ever be incomplete and liable to 

 subversion till the particular agents here alluded to have been re- 

 solved into their constituent principles. The obstacles, however, 

 which impede the progress of this investigation, are much greater 

 than may appear at first sight ; and among these are particularly 

 mentioned the difficulty of obtaining the acids completely separated 

 from all other substances, which, by their presence, will ever tend to 

 introduce uncertainty into the results of the process ; it being ob- 

 served that the attraction between compound particles at all times 

 increases in proportion as we recede from the point of saturation, 

 and that the smallest remnant is often sufficient to perplex all further 

 analysis. The liquid state is thought to be totally unfit for the pur- 

 pose of this inquiry : and after some other strictures, it is shown that 

 the state of the gas is the only one in which acids can become proper 

 objects of analytical investigation. 



In the series of his experiments on the muriatic acid in the gaseous 

 state, Mr. Henry employed the electric fluid as an agent much pre- 

 ferable to artificial heat. " This mode of operating," he says, 

 " enables us to confine accurately the gases submitted to experi- 

 ment ; the phenomena that occur during the process may be di- 

 stinctly observed, and the comparison of the products with the ori- 

 ginal gases may be instituted with great exactness." The action of 

 the electric fluid itself, as a decomponent, is no doubt extremely 

 powerful ; since it is capable of separating from each other the con- 

 stituent parts of water, of the nitric and sulphuric acids, of the vege- 

 table alkali, of nitrous gas, and of several other bodies whose com- 

 ponents are known to be strongly united. The experiments were 



