Aluminum, Sul′phate of

Al 2 (SO 4 ) 3 . Syn. Sesquisul′phate of Alumina , Neutral s. of a. , Alu′minæ sul′phas , A. sesquisul′phas , L. Prep. 1. Saturate dilute sulphuric acid with hydrate of aluminum, gently evaporate, and crystallise. 2. (Crude, commercial.) By mixing clay and oil of vitriol, in the way described under Alum. The product is the ‘ concentrated Alum ’ of the dyers. Prop. Its crystals are needles and thin pearly plates; soluble in 2 parts of water; taste astringent, and somewhat sweetish; reaction acid; a full red heat expels its acid, leaving a residuum of pure alumina; with the sulphates of pota ium, sodium, and ammonium, it forms alum. Uses, . In the arts , chiefly as a substitute for alum; the sulphate of pota ium in the latter, being found to be an unnece ary and costly ingredient, only useful to purify the salt from iron, by forming a compound of easy crystallisation; an object that may be effected with greater certainty by cheaper methods. In medicine , as a wash for foul and ill-conditioned ulcers; and as an astringent and antiseptic injection. M. Gannal has succe fully employed a solution of this salt to preserve animal bodies, by throwing it into the arteries. Even an enema of 1 quart of it, or an injection of a like quantity into the œsophagus, will suffice to preserve a body for several weeks. The mineral called Al′unite or Alu′minite , found near New haven (Su ex), is a native sub sulphate or basic sulphate ( DISUL′PHATE ) of alumina.