Immagini della pagina
PDF
ePub

appeared at Vienna. This edition, which is very different from any of the former, was translated from the French by one Godar, who was not a German, and who on that account apologises in the preface for the badness of his style. All these editions, however, are imperfect; for the original contains five books, as we learn from Leibnitz, who caused them to be transcribed, * In the year 1751 a new translation came out at Paris, entitled Metallurgy, or the art of extracting and purifying metals, translated from the Spanish of Alphonso Barba, by M. Gosfort, with the most curious dissertations on mines and metallic operations; † of this translation the celebrated abbé Lenglet de Fresnoy is said to have been the editor.

To judge by two of the German editions, Gobet has done Barba an injustice. In that of 1676, I find Barba expressly says, he does not believe the ancients were acquainted with the art of extracting silver from pounded ore by the means of quicksilver. This, certainly, does not indicate that he laid claim to the invention: besides, he every where speaks of amalgamation as an art long used in

p. 20.

See Prodromus bibliothecæ metallica. Wolfenbuttle 1732, 8vo.

+Metallurgie, ou l'Art de tirer et purifier les metaux. Traduite de l'Espagnol d'Alphonse Barba, par M. Gosfort; avec les dissertations les plus rares sur les mines et les operations metalliques. Paris 1751, 12mo. 2 tom.

La France littéraire. Paris 1769, 2 vol. 8vo. ii. p. 410.

America, but complains of the negligence with which it was practised. In a passage, however, in the Vienna edition, and which has probably been added by Gobet, we are told that, in the year 1609, Barba attempted to fix quicksilver, and with that view bethought himself of mixing it with fine pounded silver ore; that he at first imagined, with surprise, that he had obtained a mass of silver, but that he soon perceived that the mercury was not changed into silver, but had only attracted the particles of that metal. "I was," adds Barba,

[ocr errors]

highly pleased with my new discovery of ma"naging ore, of extracting its contents, and of "refining it; and this method I continued to prac"tise."-I imagine that Barba was still in Europe in 1609, and made that experiment before he was acquainted with the smelting-works in America. I am, however, of opinion, that one will see by the original, that Barba did not wish to claim the invention of amalgamation as practised in the mines of America.

DRY GILDING.

DRY GILDING, as it is called by some workmen, is a light method of gilding, by steeping linen rags in a solution of gold, then burning them; and, with a piece of cloth dipped in salt-water, rubbing

the ashes over silver intended to be gilt. This method requires neither much labour, nor much gold, and may be employed with advantage for carved work and ornaments. It is however not durable.

I am of opinion, that this manner of gilding is a German invention, and that foreigners, at least the English, were first made acquainted with it about the end of the last century; for Robert Southwell describes it in the Philosophical Transactions for the year 1698, and says, that it was known to very few goldsmiths in Germany.

GOLD VARNISH.

As mankind could not have every thing that they wished for of gold, they were contented with incrusting many articles with this precious metal. For that purpose the gold was beat into plates, with which the walls of apartments, dishes, and other vessels were covered. In early ages, these plates were thick, so that gilding in this manner was very expensive;* but in process of time the expense was much lessened, because the art was discovered of making these gold plates thinner, and of laying them on with a size. Articles, however,

* One may see in Homer's Odyssey, book iii. v. 432, the process employed for gilding, in this manner, the horns of the cow brought by Nestor as an offering to Minerva.

ornamented in this manner were still costly, and the valuable metal was always lost. Yellow golden colours of all kinds were then tried; but these did not fully produce the required effect, as they wanted that splendour peculiar to metals, and appeared always languid and dull. It was not till modern times that artists conceived the idea of overlaying with silver, or some cheaper white metal, such things as they wished to have the appearance of gold, and then daubing them over with a yellow transparent varnish, in order to give to the white metal the colour of gold, and to the colour the splendour of metal. "When we cover our houses "with gold," says Seneca, "do we not show that "we delight in deception? for we know that coarse "wood is concealed under that gold.*

[ocr errors]

This ingenious process, which at present is employed all over Europe in gilding wooden frames, coaches, and various articles, and which was formerly used in the preparation of the now old-fashioned leather tapestry, was invented towards the end of the 17th century. Anderson, in his Historical and chronological deduction of the origin of commerce, says, that it was introduced into England by one Evelyn in the year 1633; and quotes, in support of this assertion, The present State of England, printed in 1683.

This invention, however, does not belong to * Cum auro tecta perfundimus, quid aliud quam mendacio gaudemus? Scimus enim sub illo auro fœda ligna latitare. Epist. 115.

[blocks in formation]
[ocr errors]

the English, but to the Italians, and properly to the Sicilians. Antonino Cento, an artist of Palermo, found out the gold varnish, and in the year 1680 published there an account of the method of preparing it. That work I have never seen; but I found this information in a book printed at Palermo in 1704, and entitled The Innentions of the Sicilians.* Among the few important things contained in this book, the greater part of which is compiled from old Latin writers, there is, in the additions, a receipt how to prepare the gold varnish (vernice d'oro). The whole account I shall transcribe, as the authors of the French Journal of agriculture, commerce, and the arts, thought it worth their trouble to make it known in that work in 1778.

"Take gum lac, and having freed it from the filth and bits of wood with which it is mixed, put it into a small linen bag, and wash it in pure water, till the water no longer becomes red; then take it from the bag and suffer it to dry. When it is perfectly dry, pound it very fine; because the finer it is pounded it will dissolve the more readily. Then take four parts of spirit of wine, and one of the gum, reduced as before directed, to an impalpable powder, so that for every four pounds of

*La Sicilia inventrice; overo, le invenzione lodevoli nate in Sicilia, opera del Dottor. D. Vincenzo Auria, Palermitano: con li divertimenti geniali, osservazioni, e giunte all' istessa, di D. Antonio Mongitore, sacerdote Palermitano. In Palermo 1704. 300 pages in quarto.

« IndietroContinua »