Encyclopædia Britannica, Ninth Edition/Spirits of Hartshorn

HARTSHORN, Spirits of, a name signifying originally the ammoniacal liquor obtained by the distillation of horn shavings, afterwards applied to the partially purified similar products of the action of heat on nitrogenous animal matter generally, and now popularly used to designate solution of ammonia. See Ammonia, vol. i. p. 741, and Chemistry, vol. v. p. 509.