Patent dated December 30th, 1847, for “Improvement in the Treating and Manufacture of Gutta-percha, or any of the varieties of Caoutchouc.” Patentees, THOMAS HANCOCK, of Stoke Newington, and REUBEN PHILLIPS, of Islington, chemists. Specifications enrolled June 30, 1847. The patentees state that their improvements consist in the dissolving of gutta-percha, or any of the varieties of caoutchouc, or of reducing any of them to a soft, pulpy, and gelatinous state after they have undergone the process of “vulcanization or conversion;” also in preparing or treating unvulcanized, or unconverted solutions of any of these substances, so as to bring them into a vulcanized or converted state; and, lastly, in the moulds employed in the manufacture of articles therefrom. The term “vulcanized” or “converted” are used to designate certain processes by which these substances are rendered less liable to be injuriously affected by exposure to comparatively high temperatures, and which were described, the first in the specification of a patent granted to Mr. Thomas Hancock,[2] November 21, 1843, and the record in that of a patent granted to Mr. Alexander Parker,[3] August 25, 1846. Footnote 2: See London Mechanics Magazine, vol. xlii. pp. 112 and 150. Footnote 3: See London Mechanics Magazine, vol. xlv. p. 400. The patentees desire to be understood, that when employing the term gutta-percha, or any of the varieties of caoutchouc, as referring to all those substances known to the Indians, or natives of the country where they are produced, under the names of saiknah, gutta-tuban, gutta-percha, jintawan, dollah, &c., in this country of bottle, root, sheet, scrap, India-rubber, &c. In operating upon any of these materials, which have previously undergone the vulcanizing or converting process, it is preferred to use the cuttings or waste of them, as being an _economical application_ of what _would otherwise be useless_. These cuttings or waste, are first submitted to the action of rollers, or other suitable machinery for reducing them to shreds, and then boiled in oil of turpentine until reduced to the requisite consistency. Other solvents may be employed, such as coal, naptha, &c., but in that case, in order that the solvents may attain to a degree of temperature sufficiently high to dissolve the material, close vessels must be employed, for which reason, oil of turpentine is preferred. No fixed rule, it is stated, can be given for the guidance of the workman to enable him to determine the relative proportion of the material to the solvent, the time for conducting the operation, or the degree of temperature, on account of the varieties of the material, and the degree of vulcanization or conversion to which it has been subjected; for these and other details he must rely upon his own intelligence, and the result of actual experience.