In examining some silver ore from South America, at the government office in Paris, one piece was noticed, which, from appearance, was supposed to be exceedingly pure. However, to be quite certain, the examiner tried it, and from the resistance offered to the cutting tool, judged it to be 750 thousandths. The assay, however, gave as its purity 994 thousands, so that 6 thousands, only, of foreign materials sufficed to give it this resistance without depriving ifc of its malleability. From specimens of the same that were assayed, there were given, in analysis, 3 thousands of iron, 2 thousandths of cobalt, and thousandth ol nickel. The chemist, M. Barruel, who made the analysis, has been experimenting with the same alloy in diff erent proportions, and obtained the most perfect result, by mixing these three metals in equal parts. As there is no account of a similar alloy in any chemical work, he thinks that it might be profitably employed for various purposes, such as faucets of particular kinds, or medals where a more durable metal is required for the relief than what is generally employed as well as for many other uses. The afeove is translated from the proceedings of the French Academy of Sciences for the month of December last.