[1031] Or artificial quicksilver. In reality, hydrargyrus is prepared from the genuine minium of Pliny, the cinnabar mentioned in Chapter 36: it being obtained by the sublimation of sulphuret of mercury.
[1032] In Chapters 20 and 32.
[1033] This, probably, is the meaning of “lubrico humore compluere.”
[1034] See the end of Chapter [38].
[1035] Artificial quicksilver is still used for this purpose. See Note [971] to Chapter 32 of this Book; also Beckmann’s Hist. Inv. Vol. II. p. 295. Bohn’s Edition.
[1036] In Chapter [32]. He alludes to the use of glair of eggs.
[1037] Literally “whetstone.” He is speaking of the stone known to us as Touchstone, Lydian stone, or Basanite—“a velvet-black siliceous stone or flinty jasper, used on account of its hardness and black colour for trying the purity of the precious metals. The colour left on the stone after rubbing the metal across it, indicates to the experienced eye the amount of the alloy.”—Dana, Syst. Mineral., p. 242.
[1038] In Lydia. See B. v. cc. 30, 31.
[1039] As a test. At the present day, concentrated nitric acid is dropped on the mark left by the metal; and the more readily the mark is effaced, the less pure is the metal.
[1040] This seems to be the meaning of “si sudet protinus.”