5% Dr Davy's Obset-vatiojis cni Euchlorine. 



ted, as there appears no reason why a crust should defend the 

 metal more from euchlorine than from chlorine. 



M. Soubeiran states, that by agitating a small quantity of 

 mercury in euchlorine, under very cold water, the whole of the 

 chlorine is absorbed, and the oxygen left. In some trials, in ef- 

 fecting the absorption by agitation over mercury, I have also 

 witnessed a residue of oxygen. Why, in some instances, the 

 oxygen should be absorbed, and in others not, or only partially, 

 I have not been able to ascertain. 



The next point it appeared to me desirable to ascertain was, 

 whether chlorine could be added to euchlorine, without materi- 

 ally altering its character. If it could not, the obvious infer- 

 ence would be, that euchlorine is a definite compound. A mix- 

 ture over mercury was made, of about two volumes of euchlo- 

 rine and one of chlorine. The colour of the mixture was a 

 little lighter ; silver-leaf immersed in it was slightly tarnished ; 

 bright rolled zinc did not appear to be acted on ; and after two 

 hours, it was not visibly absorbed by the mercury, and only very 

 slightly after twenty-four hours. 



This result, then, is decidedly in favour of the conchjsion, 

 that euchlorine is rather a mixture of the deutoxide and chlorine 

 than a pure compound ; for the inference is obvious, that if 

 euchlorine can bear dilution with one-third its volume, without 

 being materially changed, the deutoxide, ajhrt'wriy may admit of 

 being diluted with chlorine, so as to reduce it to the strength of 

 euchlorine. And, the variable proportions of oxygen in the dif- 

 ferent specimens of euchlorine which I have examined, whether 

 made with a weak or a strong acid, is in accordance with the same 

 conclusion. 



My brother's sole argument, as already mentioned, for consi- 

 dering euchlorine a definite compound was, that the deutoxide 

 deprived chlorine of the power of acting on the common metals. 

 The argument was apparently a good one, but far from con- 

 clusive ; nor did he consider it so. As euchlorine has the same 

 effect in a less degree, this argument now can hardly be admitted. 

 It is more reasonable to refer the effect either to the electro-che- 

 mical influence of the deutoxide, or to chlorine, similar to that 

 of iron (in a cast iron pneumatic trough) in preventing mercury 



