Note 1161 — BOOK XXXIII. THE NATURAL HISTORY OF METALS.647 (continued 2)
John Bostock translation
Beckmann thinks that Pliny is here alluding to an artificial kind of “cæruleum.” “Pliny clearly adds to it an artificial colour, which in my opinion was made in the same manner as our lake; for he speaks of an earth, which when boiled with plants, acquired their blue colour.”—Hist. Inv., Vol. II. p. 480.