Sentence:  For similar reasons, aluminium sulphate and <WSD>alums</WSD> are used in dyeing cloth....Normally <WSD>alums</WSD> are soluble in water and insoluble in alcohols. 
Meaning of the word marked with <WSD> tags:  Any similar double sulphate in which either or both of the potassium and aluminium is wholly or partly replaced by other univalent or tervalent cations. (from 17th c.)