422 Mr. Faraday on the Condensation of Gases. 



sion to notice some years since with chloride of silver *. 

 When dry chloride of silver is put into ammoniacal gas, as 

 dry as it can be made, it absorbs a large quantity of it; 100 

 grains condensino above 1 30 cubical inches of the gas ; but 

 the compound thus formed is decomposed by a temperature 

 of 100° F. or upwards. A portion of this compound was 

 sealed up in a bent tube and heated in one leg, whilst the 

 other was cooled by ice or water. The compouiid thus heated 

 under pressure fused at a comparatively low temperature, and 

 boiled up, giving off ammoniacal gas, which condensed at the 

 opposite end into a liquid. 



Liquid ammonia thus obtained was colourless, transparent, 

 and very fluid. Its refractive power surpassed that of any 

 other of the fluids described, and that also of water itself. 

 From the way in which it was obtained, it was evidently as 

 free from water as ammonia in any state could be. When 

 the chloride of silver is allowed to cool, the ammonia imme- 

 diately returns to it, combining with it, and producing the 

 original compound. During this action a curious combination 

 of effects takes place : as the chloride absorbs the ammonia, 

 heat is produced, the temperature rising up nearly to 100°; 

 whilst a few inches off", at the opposite end of the tube, con- 

 siderable cold is produced by the evaporation of the fluid. 

 When the whole is retained at the temperature of 60°, the 

 ammonia boils till it is dissipated and re-combined. The 

 pressure of the vapour of ammonia is equal to about 6-5 at- 

 mospheres at 50°. Its specific gravity was 0*76. 



Muriatic Acid. 

 When made from pure muriate of ammonia and sulphuric 

 acid, liquid muriatic acid is obtained colourless, as Sir Hum- 

 phry Davy had anticipated. Its refractive power is greater 

 than that of nitrous oxide, but less than that of water ; it is 

 nearly equal to that of carbonic acid. The pressure of its 

 vapour at the temperature of 50°, is equal to about 40 atmo- 

 spheres. 



Chlorine. 

 The refractive power of fluid chlorine is rather less tlian 

 that of water. The pressure of its vapour at 60° is nearly 

 equal to 4 atmospheres. 



Attempts have been made to obtain hydrogen, oxyoren, 



fluoboracic, fluosilicic, and phosphuretted hydrogen gases in 



the liquid state ; bui though all of them have been subjected 



to great pressure, they have as yet resisted condensation. 



* Quarterly Journal of Science, vol. v. p. 74. 



The 



