ASSAYING, taken generally, implies an examination or analysis of any substance, whose constituent parts are to be chemically determined. The term, however, more particularly relates to the ascertaining the qualities of Gold and Silver in relation to their state of purity; and in the following observations we mean to confine ourselves entirely to this object.
In whatever point of view we consider the art of assaying these metals, it cannot fail to appear of great importance to the welfare and prosperity of the civilized world. Every one must be aware of the importance of a metallic cur-
rency agreeing in its standard fineness with the decree which establishes its circulation; and that it is an object of the greatest consequence to a nation, to have the means of ascertaining, with accuracy, the value of the coins issued by the authority of the Monarch. Since the reign of Henry the Eighth, we have had no capricious and unjustifiable changes in the standard fineness of our coins. That monarch, as Dr Henry remarks, "after he had squandered all his father's treasures, the grants he had received from Parliament, and the great sums he had derived from the dissolution of the religious houses, began to diminish his coins both in weight and fineness. This diminution at first was small, in hopes, perhaps, that it would not be perceived; but after he had got into this fatal career, he proceeded by rapid steps to the most pernicious lengths. In the thirty-sixth year of his reign, silver money of all the different kinds was coined, which had only one-half silver and the other half alloy. He did not even stop here; in the last year of his reign, he coined money that had only 4 oz. of silver and 8 oz. of alloy in the pound weight; and the nominal pound of this base money was worth only 9s. 3d. of our present money. He began to debase his gold coins at the same time, and proceeded by the same degrees. But it would be tedious to follow him in every step. In this degraded and debased condition Henry the Eighth left the money of his kingdom to his son and successor Edward the Sixth. This shameful debasement of the money of his kingdom, was one of the most imprudent, dishonourable, and pernicious measures of his reign; it was productive of innumerable inconveniences and great perplexity in business of all kinds, and the restoration of it to its standard purity, was found to be a work of great difficulty." Henry's History of Great Britain, Vol. XII. p. 336 and 337.
To possess the art, therefore, by which such dishonourable proceedings as are just detailed, may be speedily detected, is evidently an object of the greatest utility; in as much as the debasement of the coin would require an adjustment of the relative value of commodities to the degraded standard; and the more facility that can be given to this adjustment, the less perplexity and injury will be sustained by the public.
The importance of the art of assaying will farther appear, when we consider the extent of the manufacture of plate, and ornamental articles of gold and silver; the standard value of which is determined by an assay of a few Troy grains only. The nicety and delicacy of the operation must be great, and much practical experience requisite to obtain uniformly a satisfactory result.
The principle of assaying gold and silver is very simple; it consists of two operations—the separation of the alloy from the precious metals, and the parting of these latter from each other.
Before proceeding to the detailed description of these processes, we shall describe the furnaces and implements used in the art of assaying.