197 
several gases into liquids. 
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 condensing above 130 cubical inches of the gas : but 
the compound thus formed is decomposed by a temperature 
of ioo° 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 compound thus 
heated under pressure fused at a comparatively low tempe- 
rature, 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 im- 
mediately 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 ioo°; 
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 6o°, 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 0.7 6 . 
* Quarterly Journal of Science, vol. V. p. 74. 
