186
Pourquoy reluient les fenestres de verre si fort? Pourtant que la nature de l’estain, duquel elles sont basties par dedans, fort clere, meslée avec le verre cler aussi de lui mesme reluyst d’avantage; et le quel estain outrepassant ses raïons par les petits pores du verre, et augmentant doublement la face extérieure du dit verre, la rend grandement clere. – Problemes d’Alexandre Aphrod., traduit par M. Herret. Paris 1555, 8vo, p. 50.
187
Origin. lib. xvi. 15, p. 394.
188
Origin. lib. xvi. 18, p. 396.
189
Lib. xxxvi. cap. 26, p. 759.
190
Bayle, Diction. Histor. vol. iv. p. 462.
191
Printed at Leipzig, 1504, in small folio. There is an edition also printed at Cologne in 1624, and Fabricius quotes a Venetian edition. Pisanus seems to have been a by-name given by some one to Peckham.
192
Specul. Natur. ii. 78, p. 129.
193
Ars Magna, cap. lxvii. p. 517, in Lullii Opera. Argent. 1607, 8vo.
194
Opus Majus, ed. Jebb. Lond. 1733, fol. p. 346.
195
Franc. Assisiatis et Ant. Paduani Opera. Lugd. 1653, fol.
196
Nicephori Schol. in Synesium, in Synesii Op. Par. 1612, fol. p. 419.
197
In the collection of antiquities at St. Denis, an ancient mirror was shown, which was said to have belonged to Virgil. It was oval, and before Mabillon let it fall, was fourteen inches in length and twelve in breadth, and weighed thirty pounds. It is transparent, and of a brownish-yellow colour. According to experiments made on purpose, it was found to consist of artificial glass, mixed with a considerable portion of lead; and as it had been preserved in the above collection from the earliest periods, the practice of adding lead to glass must be very old. But whether this mirror was covered at the back, and how it was covered, though these are the most important points, I find nowhere mentioned. In the collection of the Grand Duke of Tuscany there is a piece of the same kind, said also to have been the mirror of Virgil. See Le Veil, Kunst auf Glas zu malen, Nurnb. 1779, 4to, p. 23, and Hist. de l’Acad. des Sciences, 1737, p. 412.
198
Villaret, Hist. de France. Par. 1763, xi. p. 142.
199
In Miscellanea Berolinensia, i. p. 263; but nothing further is said respecting the art, than that it was daily used in the glass-houses. Had I an opportunity, I should make experiments of every kind in order to discover a method of forming plane mirrors also in the like manner.
200
Wecker, in his book De Secretis, lib. x. p. 572, seems to say, that one must lay the saturated tin leaf so carefully on the glass plate, that no air can settle between them. According to Garzoni, the tin leaf is spread out on a smooth stone table, and after it has been rubbed over with quicksilver, the glass is placed above it.
201
Tome iii. p. 87, art.
202
Dict. Géog. de la France. Amst. 1762, fol. v. pp. 415, 672.
203
A furnace for casting large glass plates, before it is fit to be set at work, cost, it is said, 3500
204
Mariette, Traité des Pierres gravées. Par. 1750, fol.
205
The two ancient glasses found at Nismes, and described in Caylus’ Recueil d’Antiquités, ii. p. 363, were probably of this sort.
206
Natter, Traité de la Méthode antique de graver en Pierres fines, comparé avec la Méthode moderne. Lond. 1754, fol.
207
Of this kind were the
208
See Sandrart’s Teutsche Akademie, vol. i. part 2, p. 345, where there is much valuable information respecting the German artists. Compare also Doppelmayer’s Nachricht von Nürnberg. Künstlern.
209
Oculus Artificial. iii. p. 79.
210
Lib. xxxvii.
211
Cap. 52, p. 59.
212
Origin. xvi. 8.
213
De Miner. lib. ii. 2.
214
Traité des Pierres gravées, i. pp. 90, 156.
215
Ibid. p. 156.
216
In the preface, p. 15.
217
Ueber den Nutzen d. geschnitt. Steine. Altenb. 1768, p. 42.
218
Le Veil, iii. p. 19. This anecdote however is not mentioned by Mezeray, Castelnau, or Laboureur; and Bayle must have been unacquainted with it, or he would have introduced it into his long article on the Duchesse d’Estampes.
219
Doppelmayer, p. 232.
220
Abhandlungen der Schwed. Akad. xxxiii. p. 122.
221
Halle, Fortgesetzte Magie. Berlin, 1788, 8vo, i. p. 516. This author says that the invention came from England, where it was kept very secret; but the honour of the second invention belongs to H. Klaproth.
222
Schwanhard, by the acuteness of his genius, proved what was before considered as impossible, and found out a corrosive so powerful that the hardest crystal glass, which had hitherto withstood the force of the strongest spirits, was obliged to yield to it, as well as metals and stones. By these means he delineated and etched on glass, figures of men, some naked and some dressed, and all kinds of animals, flowers, and plants, in a manner perfectly natural; and brought them into the highest estimation. – Sandrart, Teutsche Akademie, i. 2, p. 346. – Doppelmayer, p. 250, says, “After 1670 he accidentally found out by the glass of his spectacles, upon which some aquafortis had fallen, becoming quite soft, the art of etching on glass.”
223
Breslauer Sammlung zur Natur- und Medicin-Geschichte. 1725, January, p. 107. “Invention of a powerful acid by which figures of every kind, according to fancy, can be etched upon glass. – When
224
Klindworth covers the glass with the etching ground of the engravers; but in the Annals of Chemistry for 1790, ii. p. 141, a solution of isinglass in water, or a turpentine oil varnish, mixed with a little white lead, is recommended. Complete instructions for acquiring this art may be found there also.
225
De Lapidibus, sect. 19.
226
See Ephemerid. ac Nat. Cur. 1676, Dec. 1, obs. 13, p. 32; and Elsholtii De Phosphoris Observationes, Berol. 1681, 4to.
227
G. C. Kirchmaieri