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IX. On the Union of Ammonia Nitrate with Ammonia. By Edward Divers, M.B. 
Communicated by Professor Odllxg, M.B . , F.B.S. 
Received. October 29, 1872, — Read January 9, 1873. 
1. Ammonia nitrate possesses the somewhat remarkable property of combining with 
large quantities of ammonia. The product is a liquid the composition of which varies 
with the temperature and pressure to which it is subjected. It appears from its 
properties to be a solution of ammonia nitrate in liquefied ammonia, analogous in every 
respect to an aqueous solution of a salt, its formation being a phenomenon precisely 
like that of the deliquescence of a salt in a moist atmosphere. 
2. The liquid was prepared by bringing dry ammonia gas into contact with dry 
ammonia nitrate in a liask loosely closed by a vulcanized caoutchouc stopper (to 
diminish loss of ammonia by diffusion) and imbedded in ice. The tube conveying the 
ammonia passed through the stopper and reached nearly to the bottom of the flask. 
Care was taken to ensure as much as possible the absence of moisture. The nitrate 
was dried either by leaving it for a month or more spread out in crushed crystals on the 
floor of an air-tight glass chamber, in which were placed dishes of oil of vitriol, or by 
exposing it for some hours in an oven to a temperature only a little below its melting- 
point*. The nitrate was put into the dry and warm flask with as little exposure as 
possible, by scooping it up rapidly with the mouth of the flask direct from the vessel in 
which it had been dried. The flask was then at once closed and kept so until all 
arrangements were complete for passing the ammonia into it. The ammonia was dried 
by sending it through a glass tube more than 50 centimetres long, closely packed with 
very small pieces of stick potash ; but before entering this tube it was deprived of most 
of its moisture by being made to pass through a long coiled tube surrounded with ice 
and thus cooled. 
3. The condensation of the ammonia by the nitrate takes place slowly at ordinary 
temperatures, and in the cooled flask is complete until the point of saturation with 
ammonia is approached. The nitrate soon shows signs of deliquescence in the 
ammonia, and, after awhile, entirely liquefies. The resulting liquid still, however, 
possesses the power of condensing ammonia, and that to a considerable extent ; while, on 
the other hand, the liquid saturated with ammonia can dissolve an additional quantity of 
ammonia nitrate. Raising the temperature of the liquid, loss of ammonia being 
* As the latter proved a less certain method of obtaining the nitrate quite dry, in consequence apparently 
of slight decomposition of the nitrate, the former only was employed in preparing the specimens of the liquid 
intended for the determination of its physical properties. 
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