124 On Sir H. Davy's Theory of [Aug. 



the state of peroxide, unite with 15*67 of oxygen; which quan- 

 tity of oxygen, on the principles of the old theory, can convert 

 53*93 of muriatic acid into oxymuriatic gas; or (which is the 

 same thing), on the basis of the new theory, can unite with the 

 hydrogen contained in that quantity of muriatic acid gas. But 

 it appears by Proust's analysis, that 62*67 of peroxide of copper 

 cannot combine with, or act on more than 37*8 of muriatic 

 acid. 



A deficiency of previous analyses, in which I could confide, 

 prevented my examining in detail Mr. J. Davy's account of the 

 compounds of chlorine with tin, iron, manganese, zinc, arsenic, 

 antimony, and bismuth. I may, however, be permitted to say 

 a few words respecting the compounds of iron. It is stated by 

 Mr. J. Davy, that ferranea has more chlorine than ferrane, and 

 that the solutions of these compounds are the red and green 

 muriates of iron respectively. Sir H. Davy* states, that a 

 solution of the red muriate may be converted into the green by 

 sulphureted hydrogen. This is easily explained, if we suppose, 

 according to the old theory, that the iron is converted into a 

 protoxide by the sulphureted hydrogen : but if we suppose the 

 iron to be in both cases in the metallic state, or, in other words, 

 exposed to a substance, with which it cannot unite until it has 

 assumed that state, the effect of the sulphureted hydrogen seems 

 by no means easily explained. 



Horn-lead is said by Mr. J. Davy to contain 74*22 of lead, 

 and 25 # 78 of chlorine. According to Kirwan's analysis, it has 

 76 of lead,f and 18*23 of muriatic acid; which, by the new 

 theory, can yield only 17"6 of chlorine. In this case, the pro- 

 portion of lead seems to answer very well ; but that of chlorine 

 is over-rated, by &*18 per cent. 



Again, by the analysis of Kirwan, horn-lead contains 5*77 of 

 oxygen ; which, on the principles of the old theory, are suffi- 

 cient to form 25*64 of oxymuriatic gas, by union with muriatic 

 acid. Is this very singular coincidence, with the others before 

 stated, to be regarded as merely accidental ? 



III. When carefully dried, Oxymuriatic Gas is incapable of 

 acting on Charcoal. 



This seems accounted for, on the old theory, by saying, that 

 the oxymuriatic gas, if it acted on the charcoal, and imparted 

 its oxygen to it, must give rise to a quantity of muriatic acid ; 

 but that this acid being incapable of existing in an insulated 

 state, and there being no water present, those actions by which 

 its evolutions would be caused are prevented. In this way, the 

 whole comes to be merely an additional instance of the power of 



* Researches, &c. p. 182. + Thomson's System, &c. iii. p. 265. 



