LIQUEFACTION OF GASES. 



621 



Plainly, the power of producing liquid air opens to applied science 

 new horizons. There is no need to prove that, from the purely scien- 

 tific and philosophical point of view, M. Cailletet's experiments are 

 of supreme importance. 



We will conclude this article with a description of the little 

 lecture-room or laboratory apparatus, constructed by M. Ducretet, 

 to show how, according to Cailletet's process, gases are liquefied. 

 It is a copy of the essential parts of the apparatus at Chatillon-sur- 

 Seiue. The bell-glass is modified. The screw-press, too, is represent- 

 ed here by a more portable pump. The accompanying figure, which 



Fig. 3. Small Apparatus for liquefying Gases. 



represents the apparatus in section, will enable us to give a more de- 

 tailed description of the system devised by M. Cailletet. 



T T is a glass tube, containing the gas to be compressed ; a cur- 



