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which is soluble in both hot and cold water. Rye meal, potato meal, and flour have been used in the production of briquettes, and in Dixon's patent fuel, which is so extensively used in England, dextrine is the cementing substance, supplemented by hard pitch, fusel oil and alum. These briquettes have given most excellent results both in smelting tests and for household purposes.

Irish Moss.—This material, which was used formerly and had the merit of being very cheap, was hygroscopic and therefore has been laid aside.

Paper Pulp or Cellulose.—Patents were taken out for the use of this material for bond, but after tests on a large scale it was found that briquettes made with it would not withstand moisture, and after experiments failed to remedy the defect it was abandoned.

Molasses.—This material was brought into use as bond for briquettes by Bérard, but in 1884 its use was greatly extended by Saltery's patent for briquetting ores, coal, coke, sawdust, etc. Coal briquettes made with it have all the characters of those agglomerated with hard pitch except their imperviousness to moisture. If this property can be attained by the addition of a small amount of linseed oil, as has been suggested, the cheapness of the bond will be greatly in favor of its use. The quantity required for successful agglomeration depends upon the percentage of sugar and gummy substances in the molasses, and in some measure also on the caking or non-caking character of the coal. It is usually between '1 and 1½ per cent of the coal. There seems to be some improvement needed in the technique or machinery of the operation for mixing the molasses through the coal, and it is also necessary to dry the briquettes artificially before they can be stored or shipped.

INORGANIC BONDS.

Magnesia Cement.—This is a patent cement composed of magnesia and chloride of magnesia with 50 to 60 per cent of water of hydration. It is produced from the refuse of the potash works at Stassfurt. It forms a very plastic paste with water, which hardens under change of temperature.

The cementing power of this material is so great that it will bind together twenty times its own weight of other substances, such as sand, etc., into blocks so hard that they will withstand a pressure of 500 to