238 Mr. Faraday on the Liquefaction of Gases. 



densation, and even combination, possessed by muriatic acid gas 

 in contact with oil of turpentine, may belong to it under a little 

 pressure, in contact with common oil, and thus have occasioned 

 the results Mr. Northmore describes. 



Sulphurous Acid Gas. — With regard to this gas, Mr. Northmore 

 says, " having collected about a pint and a half of sulphurous 

 acid gas, I proceeded to condense it in the three cubic inch receiver, 

 but after a very few pumps the forcing piston became immoveable, 

 being completely choked by the operation of the gas. A suffi- 

 cient quantity had, however, been compressed to form vapour, 

 and a thick slimy fluid, of a dark yellow colour, began to trickle 

 down the sides of the receiver, which immediately evaporated with 

 the most suffocating odour upon the removal of the pressure." 

 xiii 236. This experiment, Mr. Northmore remarks, corroborates 

 the assertion of Monge and Clouet, that by cold and pressure they 

 had condensed this gas. The fluid above described was evidently 

 contaminated with oil, but from its evaporation on removing the 

 pressure, and from the now ascertained low pressure of the vapour 

 of sulphurous acid, there can be no hesitation in admitting that 

 it was sulphurous acid liquefied. 



The results obtained by Mr. Northmore, with chlorine gas and 

 sulphurous acid gas, are referred to by Nicholson, in his Chemical 

 Dictionary, 8vo. Articles, Gas (muriatic acid oxygenized) and Gas 

 (sulphurous acid) ; and that of chlorine is referred to by Murray, 

 in his System, ii. 550 ; although at page 405 of the same volume, 

 he says that, only sulphurous acid " and ammonia of these gases 

 that are at natural temperatures permanently elastic, have been 

 found capable of this reduction." 



Carbonic Acid. — Another experiment in which it is very probable 

 that liquid carbonic acid has been produced, is one made by Mr. 

 Babbage, about the year 1813. The object Mr. Babbage had in 

 view, was to ascertain whether pressure would prevent decom- 

 position, and it was expected that either that would be the case, or 

 that decomposition would go on, and the rock be split by the ex- 

 pansive force of carbonic acid gas. The place was Chudley rocks, 

 Devonshire, where the limestone is dark and of a compact tex- 

 ture. A hole, about 30 inches deep and two inches in diameter, 



