[2821] “Quercus.”
[2822] “Spicata testacea.” These pavements were probably so called because the bricks were laid at angles to each other (of about forty-five degrees), like the grains in an ear of wheat; or like the spines projecting from either side of the back-bone of a fish.
[2823] “Lithostrota.”
[2824] In Chapter [24] of this Book.
[2825] See B. v. c. 17.
[2826] See B. v. c. 19.
[2827] A mineral alkali, Beckmann thinks; for it could not possibly be our saltpetre, he says. See B. xxxi. c. 46.
[2828] Beckmann discredits this story, because sand, he says, is not so easily brought to a state of fusion. Hist. Inv. Vol. II. p. 496. Bohn’s Edition.
[2829] “Magnes lapis.” See B. xxxiv. c. [42], and Chapter [25] of this Book. Beckmann is of opinion that an ore of Manganese is meant, a substance which has a resemblance to the magnet, and is of the greatest utility in making glass. Hist. Inv. Vol. II. p. 237.
[2830] This appears to be the meaning of “Quoniam in se liquorem vitri quoque ut ferrum trahere creditur.”