To begin, then, with the first question, was the manufacture of this varnish a secret? There is no reasonable doubt that it was, but only in a certain way. For a period of about two hundred years, from the time of Gaspar da Salo to that of the Bergonzi, the varnish was common to every Italian violin–maker. Cremona had no monopoly, for the knowledge and use of it extended to Padua, Venice, Rome, and Naples. It is impossible, therefore, during this long time to say that the selection of ingredients or the methods of preparation employed in the manufacture of this substance, so well known and widely used, were in any sense a secret. But a little later quite a change is observable. From a hundred Italian instruments of this later date, only a notable few can be selected as possessing the true varnish; and that this marked characteristic in the case of these few is not the result of mere chance is apparent from the fact that the artists who made them have consistently applied it to all their productions. From about 1745 to about 1760, then, the manufacture of this varnish may be properly called a secret, as being confined to a chosen few.
A bitter rivalry had always existed between the Neapolitan, Venetian, and Cremonese schools. Alessandro Gagliano, probably a pupil of Stradivarius, had established himself at Naples. Dominico Montagnana and Sanctus Seraphino were the masters of the art in Venice. The Cremonese makers seem to have relied on their sonorous, well selected wood, their established principles of construction, and their ancient reputation; the Venetian, on the beauty of their wood, and careful finish; and the Neapolitan, on their exceedingly low price.
As a knowledge of the varnish became at last confined to a few, instances are not wanting of the persecution of such by their less fortunate fellow–workmen. It is quite evident, that, apart from any considerations of beauty, the importance of the varnish as an acoustic element was well recognized.
The second question now presents itself: how was the secret lost? A careful and repeated examination, extending to a vast number of objects, reveals the fact that the varnish of the Italian violin–maker of the time of Stradivarius and before him was common to the painter, the varnisher, and the gilder as well. Let an ancient piece of Italian furniture—a chair, a cabinet, the case of a spinet or harpsichord—be examined, and, provided it has escaped modern retouching, the varnish might be by Stradivarius himself. Generally it is colorless, then the quality and texture are the indications; but occasionally it is of brilliant hues, and then it proclaims itself to the eye at once. Let specimens of a later date, say 1760, be examined; here is no such varnish. This is smooth, fairly lustrous, hard, and durable. The chair of 1725 presents a surface broken and worn away; that of 1760, one comparatively smooth, and fairly able to endure further vicissitudes of time.
Between the years 1740 and 1760, great changes in the manufacture of varnish were introduced. The old soft gums and their menstrua, capable in themselves of dissolving them, were discarded in favor of newer and more complicated processes, producing a result more durable and unchangeable under exposure and rough wear.
The old fashion of ornamenting all articles of furniture, whether of ornament or utility, with carvings, had given place to a more sober style. Broad, unrelieved surfaces, depending on the intrinsic beauty of their material, were found a relief to the eye tired with unraveling the mazes of complex carving or painted arabesque. The old, soft, badly wearing varnish no longer sufficed for protection and covering of such surfaces; hence the new processes, and, for such utilitarian purposes, superior results. The hard copal gums, hitherto undissolvable or only partially so, were found to yield entirely on proper heating and fusion. In 1750, a patent, covering a period of twenty–five years, was granted by the King of France to one Simon Martin, a fan painter, for a process of making varnish from amber, by driving off the succinic acid by means of heat, and the subsequent combination of the residue with oil. From that day to the present, various improvements in this art have gone on uninterruptedly. The field of discovery, the gates to which were opened by such pioneers as Simon Martin, being once entered, the problem of durability, hardness, and unchangeableness was soon solved. But with the laying aside of the old receipts, the Italian violin varnish became a lost art. The knowledge of its composition, naturally confined to the general manufacturers, was forgotten. There is no doubt that some of the Cremonese and other makers knew how to prepare it, but, as has been shown, its use was not confined to them. The new ingredients—the copals, amber, etc.—would naturally supersede the old as articles of import, and so by degrees those who possessed the secret—for a secret it was certainly regarded by its latest possessors—would find increasing difficulty in obtaining the old constituents. Moreover, the days of violin–making in Italy were over. England, France, and Germany were eager competitors; the stolid build of the first, the gaudy color of the second, the baked wood of the Mittenwalder, or artist of the Black Forest, and the general cheapness of all, held the market. And so it has happened that the art of the old varnish is not lost, but buried in the dust under the wheel of progress. For two hundred years it was in the hands of a nation; and though now a desire for this forgotten knowledge is confined to only a few, it would be absurd to say that persistent inquiry must fail to unravel a skein of so many ends.
The third question now presents itself: Are there any writings or clues for perusal and examination? There are many. An ingenious Frenchman, who long ago wrote a treatise on varnish, has given the following excellent list of authors who have treated upon this subject:—
“Alexis,” Piedmontese [real name of author, Hieronymus Ruscellaī]: Secrets des Arts; Milan, 1550.
Fiavoranti: Miroir Universel des Arts et des Sciences; Bologna, 1564.