Manufacturer and builder 4, 1869
Gold is not improperly called the most precious of metals. Aside from its brilliancy and color, which render it so highly prized, it possesses certain properties that give it a marked superiority over most of the other metals. Among these properties may be mentioned its malleability, ductility, and nonliability to tarnish when exposed to atmospheric action. From the circumstance that gold occurs in the metallic state, and is largely mixed with alluvial deposits, it is probable that it was the first known metal. History informs us that the art of working gold was know - main the time of Moses, and indeed it appears from different passages in the Old Testament that the ancient artificers in metals were not unacquainted with a process of refining gold. Their process, however, cannot have been similar to that now employed. Both the art of gilding with gold-leaf as well as that by means of amalgamation appear to have been known at a very remote period. The art of gilding is frequently mentioned in the Old Testament, as for instance in the first book of Kings, where mention is made of the tabernacle. Indeed, it seems that the art, particularly when practiced with the use of gold-leaf, was carried in these times to a high degree of perfection. This is shown by the fact that among the ruins of some of the apartments of the imperial palace on the Palatine Hill, at Rome, two rooms were discovered, on the walls of which gilded work was found apparently as fresh as if lately done. Both methods mentioned have been almost wholly superseded by electro-gilding. This process can be applied as well for gilding metallic objects as those composed of wood or plaster; in fact, it can be applied to any substance capable of receiving a coating of plumbago. The method of gilding by amalgamation, which consists in applying an amalgam of gold and mercury to the metallic surface to be coated, and then removing the mercury by means of heat, does not lack perfection in a technical point of view. In view, however, of sanitary considerations it presents very grave objections, not only from the fact that it injures the health of the operator, not only in that it brings about trembling, paralysis, and intensified action of the salivary glands and abscesses in the mouth, but also in tempting the workmen to an immoderate use of alcoholic beverages, which is found to lessen the trembling of their hands for a short period of time.