96 On the Liquefaction and Solidification [1844. 



On the Liquefaction and Solidification of Bodies generally 

 existing as Gases*. 



[Received Dec. 19, 1844, Read Jan. 9, 1845.] 



THE experiments formerly made on the liquefaction of gases f, 

 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, ac- 

 cording 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 ex- 

 periments on the subject ; and though my success has not 

 been equal to my desire, still I hope some of the results ob- 

 tained, 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 temperature. To obtain the pres- 

 sure, 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, 



* Phil. Trans. 1845, p. 155. f Ibid. 1823, pp. 160, 189. 



% Annales de Chimie, 1835, 1 X . 427, 432. 



