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 flask 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.