BODIES GENERALLY EXISTING AS GASES. 177 



than this without assuming that peculiar state, and whilst their vapours and liquids 

 are still considerably different from each other. Now whether the curve which ex- 

 presses the elastic force of the vapour of a given fluid for increasing temperatures 

 continues undisturbed after that fluid has passed the Cagniard de la Tour point or 

 not is not known, and therefore it cannot well be anticipated whether the coming on 

 of that state sooner or later with particular bodies will influence them in relation to 

 the more general law referred to above. 



The law already suggested gives great encouragement to the continuance of those 

 efforts which are directed to the condensation of oxygen, hydrogen and nitrogen, by 

 the attainment and application of lower temperatures than those yet applied. If to 

 reduce carbonic acid from the pressure of two atmospheres to that of one, we require to 

 abstract only about half the number of degrees that is necessary to produce the same 

 effect with sulphurous acid, it is to be expected that a far less abstraction will suffice 

 to produce the same effect with nitrogen or hydrogen, so that further diminution of 

 temperature and improved apparatus for pressure, may very well be expected to give 

 us these bodies in the liquid or solid state. 



Royal Institution , 

 Feb, 19, 1845. 



MDCCCXLV. 2 A 



