Under the name of universal cements are known many useful preparations that strongly adhere to almost any substance-wood, metal, leather, glass, etc. This is a recipe for such a cement, and it is especially useful for repairing specimens of minerals, rocks, etc. Reduce 2 oz. of clear gum arabic to powder, and dissolve it in a little water. Dissolve 1 1/2oz. of fine starch and 1/2oz. of sugar in the gum solution, and heat the mixture over a water-bath until the starch becomes clear. The cement should then be as thick as tar, and should remain so. It can be kept from spoiling by dropping in it a lump of camphor, or a little oil of cloves or sassafras. There are two universal cements that appear in the form of brown sticks: (a) shellac; and (b) a mixture of 2 parts of shellac and 1 part of Venice turpentine. These materials are melted and then cast into sticks. Another universal cement is made thus: - Dissolve 8oz. of sugar in 21 oz. of water in a glass flask on a water-bath, and to tbe thin syrup add 2 oz. of slaked lime. Keep the mixture at a temperature of about 70-75 C. for three days, shaking frequently; then cool, and decant the clear liquor.

Mix 6 1/oz. of this liquor with the same quantity of water, and in the mixture steep 16 oz. of fine gelatine for three hours after heating, to effect solution. jMuaily, add to the mixture D oz. of glacial acetic acid and I5gr. of pure carbolic acid. The latter serves as a preservative. Another: dissolve 2 oz. of isinglass or fish glue in proof spirit, and add loz. of pulverised gum ammoniac. Mix with a saturated solution of 2oz. of mastic in alcohol, heat over a slow fire, and afterwards place in well-stoppered bottles. For use, the material should be heated. This is especially suitable for china and glass.