88 On the Condensation [1823, 



NOTE ON THE CONDENSATION OF MURIATIC ACID GAS INTO THE LIQUID 

 FORM. BY SIR H. DAVY, Bart., Pres. R.S. 



In desiring Mr. Faraday to expose the hydrate of chlorine 

 to heat in a closed glass tube, it occurred to me that one of 

 three things would happen : that it would become fluid as a 

 hydrate ; or that a decomposition of water would occur, and 

 euchlorine and muriatic acid be formed ; or that the chlorine 

 would separate in a condensed state. This last result having 

 been obtained, it evidently led to other researches of the same 

 kind. I shall hope, on a future occasion, to detail some ge- 

 neral views on the subject of these researches. I shall now 

 merely mention, that by sealing muriate of ammonia and sul- 

 phuric acid in a strong glass tube, and causing them to act 

 upon each other, I have procured liquid muriatic acid : and by 

 substituting carbonate for muriate of ammonia, I have no doubt 

 that carbonic acid may be obtained, though in the only trial I 

 have made the tube burst. I have requested Mr. Faraday to 

 pursue these experiments, and to extend them to all the gases 

 which are of considerable density, or to any extent soluble in 

 water ; and I hope soon to be able to lay an account of his 

 results, with some applications of them that I propose to make, 

 before the Society. 



I cannot conclude this note without observing, that the ge- 

 neration of elastic substances in close vessels, either with or 

 without heat, offers much more powerful means of approxi- 

 mating their molecules than those dependent upon the appli- 

 cation of cold, whether natural or artificial; for as gases di- 

 minish only about ^j in volume for every degree of Fahr- 

 enheit's scale, beginning at ordinary temperatures, a very 

 slight condensation only can be produced by the most power- 

 ful freezing mixtures not half as much as would result from 

 the application of a strong flame to one part of a glass tube, 

 the other part being of ordinary temperature : and when at- 

 tempts are made to condense gases into fluids by sudden me- 

 chanical compression, the heat, instantly generated, presents a 

 formidable obstacle to the success of the experiment ; whereas 

 in the compression resulting from their slow generation in 

 close vessels, if the process be conducted with common precau- 

 tions, there is no source of difficulty or danger ; and it may be 



