Condensation of Several Gases into Liquids. 357 



aqueous solution of cyanogen, occurred. The pressure of 

 the vapour of cyanogen appeared to he 3.6 or 3.7 atmos- 

 p^ieres at 45° Fahr. It specific gravity was nearly 0.9. 



*' Ammonia. — Wlien 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 condensing above i30 cubical 

 inches of the gas : but the compound thus formed is de- 

 composed 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 oc 

 water. The compound 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, frans- 

 parent, and very fluid. Its refractive power surpassed that 

 of any other of the fluids described, and that also of water 

 itself. When the chloride of silver is allowed to cool, the 

 ammonia immediately returns to it, combining with it, 

 and producing the original compound. During this action 

 a curious combination of effects takes place; as the chlo- 

 ride absorbes the ammonia, heat is produced, the tempera- 

 ture rising up nearly to 100° ; whilst a few inches off, at the 

 opposite end of the tube, considerable 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 dissi- 

 pated and re-combined. The pressure of the vapour of 

 ammonia is equal to about 6.5 atmospheres at 50°. Its 

 specific gravity was 0.76. 



" Muriatic Acid. — When made from pure muriate of 

 ammonia and sulphuric acid liquid muriatic acid is ob- 

 tained colourless, as Sir Humphry Davy had anticipa- 

 ted. 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 tem- 

 perature of 50°, is equal to about 40 atmospheres. 



" Chlorine. — The refractive power of fluid chlorine is 

 rather less than that of water. — The pressure of its vapour 

 at 60° is nearly equal to 4 atmospheres. 



Mr, Faraday has made many similar experiments on 

 QJther gases, but though he has not succeeded in conden'- 



