A History of Inventions and Discoveries: Gold Varnish.
A History of Inventions and Discoveries.
By John Beckmann,
Public professor of economy in the University of Gottingen.
Translated from the German, by William Johnston.
Third edition, carefully corrected, enlarged by the addition of several new articles.
In four volumes.
Printed for Longman, Hurst, Rees, Orme, and Brown; Baldwin, Cradock, and Joy; R. Priestley; R. Scholey; T. Hamilton; W. Otridge; J. Walker; R. Fenner; J. Bell; J. Booker; E. Edwards; and J. Harding.
* 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.
*2 Cum auro tecta perfundium, quid aliud quam mendacio gaudemus? Seimus enim sub illo auro foeda ligua latiture. Epist. 115. 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, 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."*2
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.
* 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 quaarto. This invention, however, does not belong to 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 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 pound of spirit you may have one of gum: mix these together, and, having put them into an alembic, graduate the fire so that the gum may dissolve in the spirit. When dissolved, strain the whole through a strong piece of linen cloth; throw away what remains in the cloth, as of no use, and preserve the liquor in a glass bottle closely corked. This is the gold varnish which may be employed for gilding any kind of wood."
"When you wish to use it, you must, in order that the work may be done with more smoothness, employ a brush made of the tail of a certain quadruped called the vari, well known to those who sell colours for painting; and with this instrument dipped in the liquor wash gently over, three times, the wood which has been silvered. You must, however, remember every time you pass the brush over the wood to let it dry; and thus your work will be extremely beautiful, and have a resemblance to the finest gold."
After this invention was made known, it was not difficult to vary, by several methods, the manner of preparing it. Different receipts, therefore, have for that purpose been given in a number of books, such as Croker's Painter, and others: and, on this account, young artists are frequently at a loss which to choose; and when a receipt is found better than another, experienced artists keep it always secret.
With the preparation of that varnish used for gilding leather-tapestry Reaumur was acquainted, and from his papers it was made known by Fougeroux de Bondaroy. The method of making the English varnish was communicated by Scarlet to Hellot, in the year 1729; and by Graham to Du Fay, in 1738. In the year 1761, Hellot gave the receipt to the Academy of Sciences at Paris, who published it in their Memoirs for that year.
If it be true, as Fougeroux says, that gilded tapestry was made above two hundred years ago, it might be worth the little trouble that such an examination would require to investigate the method used to gild it. Nothing would be necessary but to rub a piece over with rectified spirit of wine, which would dissolve the varnish, and discover the metal.