The following process and mixtures, patented by Garman and Siegfried, and owned by the Steel Refining and Tempering Co., of Boston, Mass., cost the U. S. Government $10,000 for the right of using in their shops, and is said to impart extraordinary hardness and durability to the poorest kinds of steel. Siegfried's specification reads as follows: -

"I first heat the steel to a cherry red in a clean smith's fire, and then cover it with chloride of sodium (common salt), purifying the fire also by throwing in salt. I work the steel in this condition, and while subjected to this treatment, until it is brought into nearly its finished form. I then substitute for the salt a compound composed of the following ingredients, and in about the following proportions: One part by weight of each of the following substances: chloride of sodium (salt), sulphate of copper, sal-ammoniac, and sal-soda, together with 1/2 part by weight of pure nitrate of potassa (saltpeter), said ingredients being pulverized and mixed; I alternately heat the steel and treat it by covering with this mixture and hammering it until it is thoroughly refined and brought into its finished form. I then return it to the fire and heat it slowly to a cherry red, and then plunge it into a bath composed of the following ingredients, in substantially the following proportions for the required quantity: of rain-water 1 gal., alum, sal-soda, sulphate of copper, of each 1 1/2 oz., of nitrate of potassa (saltpeter) 1 oz., and of chloride of sodium (salt) 6 oz.

These quantities and proportions are stated as being what I regard as practically the best, but it is manifest that they may be slightly changed without departing from the principles of my invention."

U. S. Mint Test for Counterfeit Silver. - Make a solution of 24 grs. nitrate of silver, 30 drops nitric acid, and 1 oz. of water; scrape the coin to be tested and apply a drop of the liquid; if the coin turns black, reject it.