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VI. On the Liquefaction and Solidification of Bodies generally existing as Gases. By 

 Michael Faraday, Esq., D.C.L. F.R.S., Fullerian Prof. Chem. Royal Institution, 

 Foreign Associate of the Acad. Sciences, Paris, Corr. Memb. Royal and Imp. 

 Acadd. of Sciences, Petershurgh, Florence, Copenhagen, Berlin, Gottingen, 

 Modena, Stockholm, 6^c. 8fc. 



Received December 19, 1844, — Read January 9, 1845. 



1 HE experiments formerly made on the liquefaction of gases*, and the results which 

 from time to time have been added to this branch of knowledge, especially by 

 M. Thilorier-j-, have left a constant desire on my mind to renew the investigation. 

 This, with considerations arising out of the apparent simplicity and unity of the 

 molecular constitution of all bodies when in the gaseous or vaporous state, which may 

 be expected, according to the indications given by the experiments of M. Cagniard de 

 LA Tour, to pass by some simple law into their liquid state, and also the hope of seeing 

 nitrogen, oxygen, and hydrogen, either as liquid or solid bodies, and the latter probably 

 as a metal, have lately induced me to make many experiments on the subject ; and 

 though my success has not been equal to my desire, still I hope some of the results 

 obtained, and the means of obtaining them, may have an interest for the Royal Society; 

 more especially as the application of the latter may be carried much further than I as 

 yet have had opportunity of applying them. My object, like that of some others, was 

 to subject the gases to considerable pressure with considerable depression of tempera- 

 ture. To obtain the pressure, I used mechanical force, applied by two air-pumps fixed 

 to a table. The first pump had a piston of an inch in diameter, and the second a piston 

 of only half an inch in diameter ; and these were so associated by a connecting pipe, 

 that the first pump forced the gas into and through the valves of the second, and then 

 the second could be employed to throw forward this gas, already condensed to ten, 

 fifteen, or twenty atmospheres, into its final recipient at a much higher pressure. 



The gases to be experimented with were either prepared and retained in gas 

 holders or gas jars, or else, when the pumps were dispensed with, were evolved in 

 strong glass vessels, and sent under pressure into the condensing tubes. When the 

 gases were over water, or likely to contain water, they passed, in their way from the 

 air-holder to the pump, through a coil of thin glass tube retained in a vessel filled 

 with a good mixture of ice and salt, and therefore at the temperature of 0° Fahr. ; the 

 water that was condensed here was all deposited in the first two inches of the coil. 



* Philosophical Transactions, 1823, pp. 160, 189. f Annales de Chimie, 1835, Ix. 427, 432. 



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