The following are other patents granted for roofing cement3, alluded to by us in our last number: — First.—This is the substance of a patent granted to Bradley L. Prime, of Hamilton, Ohio, March 23, 1858 : Coal tar, 1 gallons. Vegetable tar, gallon. Brimstone, 12 ounces. Asphaltum, G oz. India rubber, 21 oz. Gutta percha, 1 oz. Gum copal, 2 oz. Red oxyd lead, 8 oz. Red lead, 8 oz. Umber, 8 oz. Whiting (Spanish), 16 oz. Hydraulic cement, 4 oz. Japan varnish, pint. The india rubber is dissolved in camphene, and the gutta percha in linseed oil. The coal tar is heated to about 150 Fah., and the oxyd of lead, red lead, umber, whiting, hy7 draulic cement, rubber, and gutta percha stirred therein. The vegetable tar—previously melted with the sulphur, asphaltum, and gum copal—is then added, and the mass well stirred, until all the ingredients are incorporated. The composition is then allowed to cool, and is ready for use. It may be applied in successive coats with a brush, or by any other convenient mode. The roof of the house, to receive the cement, is first covered with canvas, strong paper, or felt. After the first coat of this cement is put on, its surface, while soft, is covered with sand, and it is then allowed to harden for about a week. Another coat is then put on and covered with sand, as before, and several successive coats may be applied in the same manner, but for common purposes, two will answer. This cement indurates, and becomes firm and durable. The following are the functions ascribed to the ingredients in the specification : — The coal and vegetable tars make a durable body with which to incorporate the other parts of the composition. Sulphur is a hardener and drier, is not affected by heat or cold, and it preserves the composition against atmospheric influences. Asphaltum is to harden the tar, and make it thicker and much stronger. The india rubber and gutta percha give elasticity to the composition; gum copal imparts toughness, and resists atmospheric influence ; the oxyds of lead harden and dry the composition; and the umber dries, hardens, and prevents the cement " flowing." The Spanish whiting is a toughener and hardener; so is the hydraulic cement; and the Japan varnish is a drier, imparts a gloss, and prevents the cement running while being laid upon paper. Claim : " I do not claim, broadly, the employment of such substances in roofing compositions. " I claim the combination of the substances described, in substantially the proportions set forth, for the manufacture of a roofing composition." Second.—The following is the'substance of the patent granted to Robert Glennon, of New Orleans, La., on the same date as the one preceding :— Ingredients : First, 3 gallons of turpentine, mixed with 5 pounds of Vandyke brown; stir well, and keep until the other mixtures are prepared. Second, 3 gallons of alcohol, and 5 pounds of gum shellac stirred until dissolved. Third, 5 gallons of boiled linseed oil, 1 pound of oil of amber, one gallon of Japan varnish, 6 pounds of sulphate of zinc, and 46 gallons of coal tar, all mixed together. These three compositions described are now thoroughly incorporated together, making the fluid or soft portion of the cement. The drier is made as follows:—Half a bushel of fresh slacked lime, 4 quarts of plaster of Paris, 4 of red ochre, and 4 of Spanish whiting. These are mixed together, dried in an oven, and kept ready for use in a dry place, j| free from atmospheric influences. Before applying the cement to a roof, one pint of the solid ingredients is added to each gallon of the soft or fluid composition, and the whole thoroughly incorporated. This cement is put on like paint, and each coat is allowed to dry before the next is applied. No sand is sprinkled on the surface of the first eoat, but it is on the surface of the second and each succeeding one, as in the previous described patent. The following shows the extent of the claim :— " I claim the composition of the ingredients described, in substantially the proportions and in the manner set forth. " I disclaim the compositions of R. H. Smith and C. R. Milks, patented 1857." These were the patents published by us last week. There was no necessity for disclaiming them, that we can discern. None of the principal ingredients in any of them is new; the claims are all based on the distinct proportions of the ingredients, and these certainly differ from one another. Any one of these cements, we think, will make a very good and cheap roofing for outhouses. Care must be exercised to have the surface of each thoroughly covered with sand, or some equally good non-conducting agent. The various functions ascribed to the ingredients of the first patent are highly amusing; but they afford a sufficient commentary upon themselves without criticism from us.
This article was originally published with the title "Roofing Cements" in Scientific American 13, 37, 294 (May 1858)