306
Historiæ Augustæ Scriptores, in vita Gallieni, cap. 12.
307
Ib. in Vopisc. vita Saturnini, c. 8.
308
Strabo, Amst. 1707, fol. lib. xvi. p. 1099. – Some consider the glass earth here mentioned as a mineral alkali that was really found in Egypt, and which served to make glass; but, as the author speaks expressly of coloured glass, I do not think that the above salt, without which no glass was then made, is what is meant; but rather a metallic oxide, such perhaps as ochre or manganese.
309
Sen. Op. Lipsii, p. 579.
310
Hist. Nat. lib. xxxvii. c. 12. A passage in Diodorus Siculus, lib. ii. c. 52, alludes, in my opinion, to this method of colouring by cementation.
311
Magia Naturalis. Franc. 1591, 8vo, p. 275.
312
Kunkel’s Ars Vitraria. Nur. 1743, 4to, pp. 98, 101.
313
Comment. Soc. Scient. Gotting. ii. p. 41.
314
Montamy von den Farben zuni Porzellan- und Email-malen. Leipsic, 1767, 8vo, p. 82. Fontanieu, p. 16.
315
[The extensive use of this substance in colouring glass and porcelain has rendered its best and most œconomical preparation a subject of interest both to the chemist and the manufacturer. Although the determination of its true chemical composition has presented obstacles almost insuperable, still many important points with regard to its manufacture have been elucidated. It has been found that the tin salt used in precipitating it must contain both the binoxide and protoxide of tin in certain proportions, and it has been also discovered that the degree of dilution both of the gold and tin solutions exerts a very perceptible influence on the beauty of the preparation. Capaun has examined this latter point with great attention, by testing all the different products as to their power of colouring glass.
The first point to be attained is the preparation of a solution of sesquioxide of tin; and for this purpose Bolley proposes to employ the double compound of bichloride of tin with sal-ammoniac (pink salt). This salt is not altered by exposure to the atmosphere, and contains a fixed and known quantity of bichloride of tin, and when boiled with metallic tin it takes up so much as will form the protochloride; as the exact quantity of the bichloride is known, it is very easy to use exactly such a quantity of tin as will serve to form the sesquichloride. 100 parts of the pink salt require for this purpose 10·7 parts of metallic tin.
Capaun recommends dissolving 1·34 gr. of gold in aqua regia, an excess being carefully avoided, and diluting the solution with 480 grs. of water. 10 grs. of pink salt are mixed with 1·07 gr. of tin filings and 40 grs. of water, and the whole boiled till the tin is dissolved. 140 grs. of water are then added to this, and the solution gradually mixed with the gold liquor, slightly warmed, until no more precipitation ensues. The precipitate washed and dried weighs 4·92 grs. and is of a dark brown colour.
M. Figuier states, as the results of his investigations, that the purple of Cassius is a perfectly definite combination of protoxide of gold and of stannic acid, or peroxide of tin, the proof of which is, that it is instantly produced when protoxide of gold and peroxide of tin are placed in contact.]
316
The original title runs thus: – De extremo illo et perfectissimo naturæ opificio ac principe terrenorum sidere, auro, et admiranda ejus natura, generatione, affectionibus, effectis, atque ad operationes artis habitudine, cogitata; experimentis illustrata. Hamburgi, 1685, 8vo.
317
Joh. Molleri Cimbria Literata. Havniæ, 1774, fol. i. p. 88.
318
Miscellanea Berolinensia, i. p. 94.
319
The author shows only, in a brief manner, in how many ways this precipitate can be used; but he makes no mention of employing it in colouring glass.
320
I cannot, however, affirm that the
321
Alchymia Andr. Libavii. Franc. 1606, fol. ii. tract. i. c. 34.
322
See Gotting. Gel. Anzeigen, 1778, p. 177.
323
It is well known that Neri’s works are translated into Kunkel’s Ars Vitraria, the edition of which, published at Nuremberg in 1743, I have in my possession. The time Neri lived is not mentioned in the Dictionary of Learned Men; but it appears, from the above edition of Kunkel, that he was at Florence in 1601, and at Antwerp in 1609. The oldest Italian edition of his works I have ever seen is L’arte vetraria – del R. R. Antonio Neri, Fiorentino. In Venetia, 1663. The first edition, however, must be older. [It is Florence, Giunti, 1612. – Ed.]
324
Neri, b. vii. c. 129, pp. 157 and 174.
325
Amst. 1651, vol. iv. p. 78. Lewis says that Furnus Philosophicus was printed as early as 1648.
326
Glauber first made known liquor of flint, and recommended it for several uses. See Ettmulleri Opera, Gen. 1736, 4 vol. fol. ii. p. 170.
327
Lewis, Zusammenhang der Künste. Zür. 1764, 2 vols. 8vo, i. p. 279.
328
The first edition was printed at Augsburg, in duodecimo, and the same year at Amsterdam. It has been often printed since, as in 1739, in 3 vols. 4to, without name or place.
329
A French translation of Orschal and Grummet is added to l’Art de la Verrérie de Neri, Merret et Kunkel. Paris, 1752, 4to. The editor is the Baron de Holbach.
330
See Peter le Vieil’s Kunst auf Glas zu malen, Nuremberg, 1779, 4to, ii. p. 25. This singular performance must, in regard to history, particularly that of the ancients, be read with precaution. Seldom has the author perused the works which he quotes; sometimes one cannot find in them what he assures us he found, and very often he misrepresents their words.
331
In what the art of Abraham Helmback, a Nuremberg artist, consisted, I do not know. Doppelmayer, in his Account of the Mathematicians and Artists of Nuremberg, printed in 1730, says that he fortunately revived, in 1717, according to experiments made in a glass-house, the old red glass; the proper method of preparing which had been long lost.
332
Ferber’s Briefe aus Welschland. Prague, 1773, 8vo, p. 114.
333
The devastations to which the productions of this beautiful art have been subjected are deeply to be regretted. It appears from the interesting Account of Durham Cathedral, published by the Rev. James Raine, that there was much fine stained glass in the fifteen windows of the Nine Altars which
“shed their many-colour’d light
Through the rich robes of eremites and saints;”
until the year 1795, when “their richly painted glass and mullions were swept away, and the present plain windows inserted in their place. The glass lay for a long time afterwards in baskets on the floor; and when the greater part of it had been purloined the remainder was locked up in the Galilee.” And in 1802 a beautiful ancient structure, the Great Vestry, “was, for no apparent reason, demolished, and the richly painted glass which decorated its windows was either destroyed by the workmen or afterwards purloined.” The exquisite Galilee itself had been condemned, but was saved by a happy chance.
334
In 1774 the French Academy published Le Vieil’s treatise on Glass-painting. He possessed no colour approaching to red, except the brick-red or rather rust-coloured enamel subsequently mentioned in the text, derived from iron.
335
It appears by a boast of Suger, abbot of St. Denis, which has been preserved, that the ancient glass-painters pretended to employ sapphires among their materials; hence, perhaps, the origin of the term