234 Mr. Faraday on the Liquefactidn of Gases. 



but he proposes to repeat the experiment and examine whether a 

 portion of the gas so dried, when received over mercury would not 

 yield water to well calcined potash, " for as it is seen that water 

 charged with a little of the gas, remained liquid in the first bal- 

 loon, at a temperature of— 21°., it is possible that a much smaller 

 quantity of water united to a much larger quantity of the gas, 

 would become capable of resisting a temperature of — 48°C. 



Sir H. Davy, who refers to this experiment in his Elements of 

 Chemical Philosophy, p. 267, urges the uncertainty attending it, 

 on the same grounds that Morveau himself had done ; and now 

 that the strength of the vapour of dry liquid ammonia is known, 

 it cannot be doubted that M. Morveau had obtained in his second 

 balloon only a very concentrated solution of ammonia in water. I 

 find that the strength of the vapour of ammonia dried by potash, 

 is equal to about that of 6.5 atmospheres at 50° F *. and accord- 

 ing to all analogy it would require a very intense degree of cold, 

 and one at present beyond our means, to compensate this power 

 and act as an equivalent to it. 



Sulphurous Acid Gas. — It is said that sulphurous acid gas has 

 been condensed into a fluid, by Monge and Clouet, but I have not 

 been able to find the description of their process. It is referred 

 to by Thomson, in his System, first edition, ii. 24; and in subse- 

 quent editions ; by Henry, in his Elements, i. 341 ; by Accum, in his 

 Chemistry, i.319 ; by Aikin, Chemical Dictionary, ii. 391 ; by Nichol- 

 son, Chemical Dictionary, article, gas (Sulphurous acid); and 

 by Murray, in his Si/stem, ii. 405. All these authors mention 

 the simultaneous application of cold and pressure, but Thomson 

 alone refers to any authority, and that is Fourcroy, ii. 74. 



It is curious that Fourcroy does not, however, mention conden- 

 sation as one of the means employed by Monge and Clouet, but 

 merely says the pas is capable of liquefaction at 28° of cold. 

 " This latter property," he adds, " discovered by citizens Monge 

 and Clouet, and by which it is distinguished from all the other 

 gases, appears to be owing to the water which it holds in solution, 

 and to which it adheres so strongly as to prevent an accurate esti- 

 mate of the proportions of its radical and acidifying principles.' 

 * Philosophical Transactions, 1823, p. 197. 





