FOOTNOTES
[757] It was because pearls are calcareous that Cleopatra was able to dissolve hers in vinegar, and by these means to gain a bet from her lover, as we are told by Pliny, 1. ix. c. 35, and Macrobius Saturn. 1. ii. c. 13. She must, however, have employed stronger vinegar than that which we use for our tables, as pearls, on account of their hardness and their natural enamel, cannot be easily dissolved by a weak acid. Nature has secured the teeth of animals against the effects of acids, by an enamel covering which answers the same purpose; but if this enamel happen to be injured only in one small place, the teeth soon spoil and rot. Cleopatra perhaps broke and pounded the pearls; and it is probable that she afterwards diluted the vinegar with water, that she might be able to drink it; though dissolved calcareous matter neutralizes acids and renders them imperceptible to the tongue. We are told that the dissipated Clodius gave to each of his guests a pearl dissolved in vinegar to drink:—“Ut experiretur in gloria palati,” says Pliny, “quid saperent margaritæ; atque ut mire placuere, ne solus hoc sciret, singulos uniones convivis absorbendos dedit.” Horace, lib. ii. sat. 3, says the same. That pearls are soluble in vinegar is remarked in Pausanias, b. viii. ch. 18, and Vitruvius, b. viii. ch. 3.
[758] That pearls are not peculiar to one kind of shell-fish, as many believe, was known to Pliny. I have a number of very good pearls which were found by my brother in Colchester oysters. It is more worthy of remark, and less known, that real pearls are found under the shield of the sea-hare, (Aplysia), as has been observed by Bohadsch in his book De Animalibus Marinis, Dresdæ, 1761, 4to, p. 39.
[759] In the time of Job, pearls were accounted to be of great value. Job, chap. xxviii. ver. 18.
[760] [When the surface of pearl is examined with a microscope, it is found to be indented by a large number of delicate grooves, which by their effect upon the light give rise to the play of colours; and if impressions of them be taken upon wax, fusible metal, lead, balsam of Tolu, &c., the impressed surface exhibits the prismatic colours in the same manner as the pearl. This principle has been applied by Mr. Barton and others to the making of ornaments, in the form of buttons, artificial jewels, &c., by grooving the surface of steel with a very fine cutting machine. The theory of the production of the colours is this: the surfaces of the grooves, from their varied inclinations, reflect the incident white light at various angles, hence the correspondence of the luminous undulations is interrupted and some of them check or interfere with one another, others continue their course. Now, ordinary white light being a mixture of coloured rays, when some of these are checked or interfered with in their progress, the remainder continue their course and appear of that colour which results from the ocular impression communicated by them.]
[761] [One of the most remarkable pearls of which we have any authentic account, was bought by Tavernier at Catifa in Arabia, a fishery famous in the days of Pliny, for the enormous sum of £110,000. It is pear-shaped, regular, and without blemish. It is rather more than half an inch in diameter at the largest part, and from two to three inches in length.—Waterston’s Encyclopædia of Commerce.]
[762] Philostrat. in Vita Apollon. lib. iii. cap. 57, edit. Olearii, p. 139. Conrade Gesner, in his Hist. Nat. lib. iv. p. 634, gives a more correct translation of the passage.
[763] Tsetzes Variorum, lib. ii. segm. 373.
[764] See Dr. Joh. Mayer’s Bemerkungen, in the fourth part of Abhandlungen einer Privatgesellschaft in Böhmen, p. 165.
[765] Abhand. der Schwed. Akadem. der Wissenschaften, vol. xxxiv. p. 89. The author of the paper alluded to had a mussel with such artificial pearls, which had been brought from China. It was a Mytilus cygneus, the swan-mussel, or great horse-mussel. Mention is made also in Histoire de l’Académie des Sciences de Paris, année 1769, of a stone covered with a pearly substance which was found in a mussel.
[766] A kind of cockles.
[767] J. C. Fabricius Briefe aus London, Dessau, 1784, 8vo, p. 104.
[768] See Schlözer’s Briefwechsel, number 40, p. 251.
[769] Dr. Stœver, in his Life of Linnæus, vol. i. p. 360, says that the manuscript containing this secret was in the possession of Dr. J. E. Smith, at London.—Trans.
[770] In his Letters, p. 104.
[771] This pretty plant, named after the father of botany, grows in Northumberland and some woods in Scotland, also in Switzerland, Siberia, and Canada, but particularly in Norway and Sweden, in shady places amidst the thick woods. The flowers, which appear in May, June and July, are shaped like a bell, rose-coloured without, yellowish in the inside, and somewhat hairy. They have a pleasant smell, especially in the evening. In Tronheim and the neighbouring parts they are drunk as tea for medicinal purposes.
[772] Pearl. An excrescence on the inside of a shell when the outer side has been perforated.
[773] See Chemnitz’s theory of the origin of pearls, in the Beschäftigungen der Berlin. Naturforsch. Gesellschaft, i. p. 348.
[774] The animal part is rendered evident on distillation by the evolution of an ammoniacal odour and a somewhat inflammable oil; and on solution in muriatic acid the animal substance is left behind.
[775] Abhand. der Schwed. Akad. iv. p. 245, and xxi. p. 142.
[776] Fabricius, in his Letters, p. 105, mentions such an experiment, which was however continued only for a year.
[777] Exercitatio Anatom. de Cochleis. Lond. 1694, p. 183.
[778] This manner of preparing margaritini may be seen in my Anleitung zur Technologie, p. 307.
[779] Massarii in Plinii Nat. Hist. lib. ix. Castigationes. Bas. 1537, 4to, cap. 35.
[780] Mercati Metallotheca, p. 211.
[781] These silver-coloured particles were examined by Reaumur, who gave a description of them in Histoire de l’Académie, année 1716, p. 229. [In the scales of fishes, the optical effect is produced in the same manner as in the real pearl, the grooves of the latter being represented by the inequalities formed by the margins of the concentric laminæ of which the scales are composed.]
[782] The artist no doubt had in view eastern pearls.
[783] Girasol. This word, which is wanting in most dictionaries, signifies opal, and sometimes that stone called cat’s-eye, Silex catophthalmus, pseudopalus, &c. Couleur de girasol is applied to semitransparent milk-white porcelain.
[784] Coques de perles are flat on one side, and are used for ornaments, one side of which only is seen. By Pliny they are called physemata. Artificial pearls of this kind have, for some time past, been employed in making ear-rings. Our toymen, after the French, give these pearls the name of perles coques; but the following account of Pouget in Traité des Pierres Précieuses, Paris 1762, i. p. 20, makes me dubious respecting them. “La coque de perle,” says he, “is not formed in a pearl-shell like the pearl; it is procured from a kind of snail found only in the East Indies. There are several species of them. The shell of this animal is sawn in two, and one coque only can be obtained from each. The coques are very small, and one is obliged to fill them with tears of mastic to give them a body, before they can be employed. This beautiful snail is found generally in the sea, and sometimes on the shore.” May not Pouget here mean that kind of snail which others call burgeau, the shells of which are, in commerce, known by the French under the name of burgaudines? Should that be the case, the animal meant would be the Nautilus Pompilius, as may be concluded from Histoire des Antilles, par Du Tertre, ii. p. 239. For the author says, “C’est de leur coque que les ouvriers en nacre tirent cette belle nacre qu’ils appellent la burgaudine, plus estimée que la nacre de perle.” Irregular pearls are called baroques, or Scotch pearls, because abundance of such were once found at Perth in Scotland. Some years ago artificial pearls of an unnatural size, called Scotch pearls, were for a little time in fashion.
[785] A complete account of the art of making glass pearls is contained in a book, which I have however not seen, entitled, L’Art d’imiter les perles fines, par M. Varenne de Beost. An extract from it may be found in Dictionnaire des Arts et Métiers, par M. Joubert, iii. p. 370. See also the articles perle and able in the Encyclopédie, i. p. 29; xii. p. 382.
[786] Traité Générale des Pesches, par. ii. p. 403, tab. 23, fig. 1 et 2.
[787] Ichthyologia, Hamb. 1624, 4to, p. 12, tab. 1, fig. 2, albula.
[788] In the Almanach de Strasburg for 1780, p. 76, among the commodities sold there were, Des écailles d’ablettes dont on tire l’essence d’orient employée pour les fausses perles.
[789] Déscription Hist. et Topogr. du Duché de Bourgogne, par M. Courtépée, tom. iv. A Dijon, 1779, 8vo, p. 534.
[790] Pouget. 4to, i. p. 19.