4d OS THE NATORZ OF OXIMURIATIC QAS* 



of the two gasses era ployed — nothing ponderable escapes ; 

 muriatic acid gas consequently is not inferred, but is im- 

 mediately perceived to be, a compound of oximuriatic gas 

 and hidrogen, and all other cases are analogous. 

 Mr. Murray's Mr. Murray, to convince me of the errour of which he 

 from 'the°com- conceived me guilty, respecting the nature of Mr. Davy's 

 bination of ox- theory, has recourse to particular instances to illustrate his 



ind mmlatk'' •'■•^"™^"^- ^^"^ ^^^^ * " ^ combine oxide of mercury and 

 acid, muriatic acid, and form calomel, I conclude therefore, that 



calomel is a compound of oxide of mercury and muriatic 

 apid. I combine muriatic acid and potash, and by dissi-i' 

 pation of the water I obtain a solid product, which I con- 

 sider as a compound of the muriatic acid and potash, and 

 I perceive in these conclusions no supposition, but a simple 

 expression of facts." If Mr. Murray can combine oxide 

 of mercury and muriatic acid, and form calomel, I havg 

 no objection to his conclusions; if the above is a simple 

 expression of facts, the theory which expresses thofse facts 

 noqst be ^correct. But 1 have not been able to witness such 

 facts. I have found, that, when muriatic acid gas is ad- 

 mitted into a., exhausted retort, containing red precipitate, 

 cprrpsive sublimate, and not calomel, is formed ; that water 

 in plenty is simultaneously produced ; and that much heat 

 is generated, sufficient indeed, when the experiment it 

 made on a pretty Itirge scale, to revive some mercury by 

 the expulsipu of jts oxigen. Mr. Murray, not attending to 

 all the phenomena, has formed a false theory. Stahl, tinding 

 sulphur produced by heating charqoal wjth sulphuric acid, 

 asserted, that sulphur is a compound of sulphuric acid and 

 phlogiston ; and Mr. Murray, Jtnowing that different me- 

 tallic compounds may be procured by treating different 

 oxides with mpriaiic acid, a^sfsrts, that these compounds 

 consist of muriatic ^cid and metallic oxides. In Stahl's 

 famous experiment, carbonip acid gas, not being then dis- 

 covered, escaped his notice; but the same cannot be said 

 <of water, which Mr. Murray has thus neglected. The 

 preceding illustration of Mr. Miirray at pncp demonstrates 

 Ihe real difference between Mr. Davy's theory and the ol4 

 byppthjesis; and tl^at the former is^ as 1 have represented it, 



a simply 



