128 On the Liquefaction of Gases. [1824. 



second balloon. This balloon was then cooled to 43'75 C., 

 and then drops of a fluid lined its interior, and ultimately united 

 at the bottom of the vessel. When the thermometer in the 

 cooling mixture stood at 36'25 C., the fluid already de- 

 posited preserved its state, but no further portions were added 

 to it; reducing the temperature again to 41 C., and hasten- 

 ing the disengagement of ammoniacal gas, the liquid in the 

 second balloon augmented in volume. Very little gas escaped 

 from the last flask, and the pressure inwards was such as to 

 force the oil of the lute into the balloon, where it congealed. 

 Finally, the apparatus was left to regain the temperature of the 

 atmosphere, and as it approached to it, the liquid of the second 

 balloon became gaseous. The ice in the first balloon became 

 liquid, as soon as the temperature had reached 2l'25 C. 



M. Morveau remarks on this experiment, that it appears cer- 

 tain that ammoniacal gas made as dry as it can be, by passing 

 into a vessel in which water would be frozen, and reduced to a 

 temperature of 21 C., condenses into a liquid at the tempera- 

 ture of 48 C., and resumes its elastic form again as the tempe- 

 rature is raised ; 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, 

 ft for as it is seen that water charged with a little of the gas, re- 

 mained liquid in the first balloon, 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 re- 

 sisting a temperature of 48C." 



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

 of Chemical Philosophy,' p. 267, urges the uncertainty attend- 

 ing 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 atmo- 

 spheres at 50 F. *, and according to all analogy [it would re- 

 quire a very intense degree of cold, and one at present beyond 

 our means, to compensate this power and act as an equivalent 

 to it. 

 ' * Philosophical Transactions, 1823, p, 197 or page 95, 



