Table of the Quantities of Gold which may be considered as having been brought into the European Market, every Year on an Average, from 1790 to 1802.
| Continents. | Gold. | ||||
|---|---|---|---|---|---|
| Ancient Continent. | lbs. Avoir. | ||||
| Asia: | |||||
| Siberia | 3740 | ||||
| Africa | 3300 | ||||
| Europe: | |||||
| Hungary | 1430 | ||||
| Salzbourg | 165 | ||||
| Austrian States | - | 165 | |||
| Hartz and Hessia | |||||
| Saxony | |||||
| Norway | |||||
| Sweden | |||||
| France | |||||
| Spain, &c. | |||||
| Total of the Ancient Continent | 8800 | ||||
| New Continent. | |||||
| North America | 2860 | ||||
| South America: | |||||
| Spanish dominions | 22,000 | ||||
| Brazil | 15,400 | ||||
| Total of the New Continent | 40,260 | ||||
The mines of America have sent into Europe three and a half times more gold, and twelve times more silver, than those of the ancient continent. The total quantity of silver was to that of gold in the ratio of 55 to 1; a very different ratio from that which holds really in the value of these two metals, which is in Europe as 1 to 15. This difference depends upon several causes, which cannot be investigated here at length; but it may be stated that gold, by its rarity and price, being much less employed in the arts than silver, the demand for it is also much less; and this cause is sufficient to lower its price much beneath what it would have been, if it had followed the ratio of its quantity compared to that of silver. Thus also bismuth, tin, &c., though much rarer than silver, are, nevertheless, very inferior in price to it. Before the discovery of America, the value of gold was not so distant from that of silver, because since that era silver has been distributed in Europe in a far greater proportion than gold. In Asia the proportion is now actually only 1 to 11 or 12; the product of the gold mines in that quarter, being not so much below that of the silver mines as in the rest of the world.
The total annual production of Gold at present has been estimated as follows.
| From | the ancient Spanish colonies of America | 10,400 | kilogrammes |
| Brazil | 600 | ||
| Europe and Asiatic Russia | 6,200 | ||
| The Indian Archipelago | 4,700 | ||
| Africa | 14,000 | ? | |
| 35,900 | = 36 tons nearly | ||
without taking into account the quantity of gold now extracted from silver.
Gold has less affinity for oxygen than any other metal. When alone, it cannot be oxidized by any degree of heat with contact of air, although in combination with other oxidized bodies, it may pass into the state of an oxide, and be even vitrified. The purple smoke into which gold leaf is converted by an electric discharge is not an oxide, for it is equally formed when the discharge is made through it in hydrogen gas. There are two oxides of gold; the first or protoxide is a green powder, which may be obtained by pouring, in the cold, a solution of potash into a solution of the metallic chloride. It is not durable, but soon changes in the menstruum into metallic gold, and peroxide. Its constituents are 96·13 metal, and 3·87 oxygen. The peroxide is best prepared by adding magnesia to a solution of the metallic chloride; washing the precipitate with water till this no longer takes a yellow tint from muriatic acid; then digesting strong nitric acid upon the residuum, which removes the magnesia, and leaves the peroxide in the form of a black or dark brown powder, which seems to partake more of the properties of a metallic acid than a base. It contains 10·77 per cent. of oxygen. For the curious combination of gold and tin, called the [Purple Precipitate of Cassius], see this article, and [Pigments Vitrifiable].
Gold beating.—This is the art of reducing gold to extremely thin leaves, by beating with a hammer. The processes employed for this purpose may be applied to other metals, as silver, platinum, and copper. Under tin, zinc, &c., we shall mention such modifications of the processes as these metals require to reduce them to thin leaves. The Romans used to gild the ceilings and walls of their apartments; and Pliny tells us, that from an ounce of gold forming a plate of 4 fingers square, about 600 leaves of the same area were hammered. At the present day, a piece of gold is extended so as to cover a space 651,590 times greater than its primary surface when cast.
The gold employed in this art ought to be of the finest standard. Alloy hardens gold, and renders it less malleable; so that the fraudulent tradesman who should attempt to debase the gold, would expose himself to much greater loss in the operations, than he could derive of profit from the alloy.
Four principal operations constitute the art of gold beating. 1. The casting of the gold ingots. 2. The hammering. 3. The lamination; and 4., the beating.