Chapter 36.. [1017] See B. Vi. Cc. 27, 28, 32.

See B. vi. cc. 27, 28, 32.

See B. iii. c. 3, Vol. I. p. 163. He alludes to the district of Almaden, in Andalusia, still famous for its quicksilver mines.

When sold by the “publicani,” or farmers of the revenue.

Of the publicani.

Red oxide of lead, a much inferior pigment to cinnabar, or the minium of Chapter 36.

In Chapter 32 of this Book.

Dana informs us that minium is usually associated with galena and with calamine. Syst. Mineral, p. 495.

“Steriles.” Barren of silver, probably; though Hardouin thinks that it means “barren of lead.” Holland renders it “barraine and void of the right vermilion.”

In Chapter 37.

B. xxxv. c. 24.

When hired by the job for colouring walls or objects of art. See B. xxxv. c. 12.

See B. xvi. c. 12, and B. xxiv. c. 4.

“Candelis.” The Abate Requeno thinks that these “candelæ” were used as a delicate cauterium, simply to keep the wax soft, that it might receive a polish from the friction of the linen.

Hence the use of it in the middle ages; a reminiscence of which still exists in our word “rubric.”

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.

In Chapters 20 and 32.

This, probably, is the meaning of “lubrico humore compluere.”

See the end of Chapter 38.

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.

In Chapter 32. He alludes to the use of glair of eggs.

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.

In Lydia. See B. v. cc. 30, 31.

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.

This seems to be the meaning of “si sudet protinus.”

A very far-fetched explanation, and very wide of the mark.

“Paulum propulsa.”

Which he supposes a concave surface to do.

This passage is noticed by Beckmann, in his account of Mirrors; Vol. II. p. 58. Bohn’s Edition.

Distorting the image reflected, by reason of the irregularities of the surface. See Seneca, Nat. Quæst. B. i. c. 5.

“Parma Thræcidica.”

He probably means, whether the surface is made convex or concave at these different angles.

A subject to which he returns in various parts of B. xxxvi.

See B. xxxiv. c. 48.

As to the identification of “stannum,” on which there have been great differences of opinion, see B. xxxiv. cc. 47, 48, and the Notes.

For some account of this artist, see Chapter 55 and the Notes at the end of this Book.

“Silver mirrors were known long before this period, as is proved by a passage in the Mostellaria of Plautus, A. 1, S. 3, l. 101, where they are distinctly mentioned. To reconcile this contradiction, Meursius remarks that Pliny speaks only of his countrymen, and not of the Greeks, who had such articles much earlier, though the scene in Plautus is at Athens.”—Beckmann, Hist. Inv. Vol. II. p. 62. Bohn’s Edition.

“Nuper credi cœptum certiorem imaginem reddi auro opposito aversis.”—“Of what Pliny says here I can give no explanation. Hardouin (qy. if not Dalechamps?) is of opinion that mirrors, according to the newest invention, at that period were covered behind with a plate of gold, as our mirrors are with an amalgam. But as the ancient plates of silver were not transparent, how could the gold at the back of them produce any effect in regard to the image? May not the meaning be that a thin plate of gold was placed at some distance before the mirror, in order to throw more light upon its surface? Whatever may have been the case, Pliny himself seems not to have had much confidence in the invention.”—Beckmann, Hist. Inv. Vol. II. p. 62.

Dr. Watson (Chemical Essays, Vol. IV. p. 246) seems to think that Pliny is here speaking of glass mirrors: “If we admit that Pliny was acquainted with glass mirrors, we may thus understand what he says respecting an invention which was then new, of applying gold behind a mirror. Instead of an amalgam of tin, some one had proposed to cover the back of the mirror with an amalgam of gold, with which the ancients were certainly acquainted, and which they employed in gilding.” See