or ALLAY, properly signifies a proportion of a softer metal mixed with a finer one. The alloy of gold is estimated by carats, that of silver by pennyweights. In different nations different proportions of alloy are used; whence their moneys are said to be of different degrees of fineness or baffle, and are valued accordingly in foreign exchanges. The chief reasons alleged for the alloying of coin are: 1. The mixture of the metals, which, when melted from the mine, are not perfectly pure. 2. The saving the expense it must otherwise cost if they were to be refined. 3. The necessity of rendering them harder, by mixing some parts of other metals with them, to prevent the diminution of weight by wearing in passing from hand to hand. 4. The melting of foreign gold or coin which is alloyed. 5. The charges of coining, which must be made good by the profit arising from the money coined. 6. And lastly, The duty belonging to the sovereign, on account of the power he has to cause money to be coined in his dominions.

In a more general sense, the word is employed in chemistry to signify the union of different metallic matters.—As an infinity of different combinations may be made according to the nature, the number, and the proportions of the metallic matters capable of being alloyed, we shall not here enter into the detail of the particular alloys, all which are not yet nearly known. Those which are used, as Bronze, Tombac, Brazils, White Copper, &c., may be found in the article Chemistry, and what is known concerning other alloys will be treated of along with the metals in the same article. See Chemistry Index.

ALLUM. See Alum.