Note 2632 — BOOK IX. THE NATURAL HISTORY OF FISHES.

“Exaluminatos.” It is clear from this passage that Pliny was acquainted with our alum, as he here clearly implies that the alum known to him was of a white colour. Beckmann, however, in his History of Inventions, asserts that our alum was certainly not known to the Greeks and Romans, and that their “alumen” was nothing else but vitriol, the green sulphate of iron, and that not in its pure state, but such as forms in mines. Pereira, however, in his Materia Medica, says, that there can be little doubt that Pliny was acquainted with our alum, but did not distinguish it from sulphate of iron, as he informs us that one kind of alum was white, and was used for dyeing wool of various colours. It is mentioned more fully in B. xxxv. c. 52, where he speaks of its use in dyeing.