I further claim, as an entirely new manufacture, the sheet caoutchouc prepared by the within described process of treatment, by the metallic solutions as herein described, as it is thereby so essentially changed in its properties as to bear but little resemblance to such articles as have, heretofore, been manufactured out of the same material, and is rendered applicable to a variety of new purposes hitherto unattempted, or attempted without success. _Nineteenth_, to Stephen C. Smith, New York, December 7th, 1837. Manufacture of India-rubber. _Twentieth_, to Charles Goodyear, Roxbury, Mass., July 24th, 1838. For manufacturing India-rubber. _Twenty-first_, to Nathaniel Hayward, Assigner to Charles Goodyear, Boston, Mass., Feb. 24th, 1839. For an Improvement in the mode of preparing India-rubber for the manufacture of various articles. Sulphur, it is known, is soluble in the essential oils, which also are the solvents usually employed for dissolving caoutchouc, the oil of turpentine being generally employed for that purpose. I take the essential oil, say oil of turpentine, and dissolve in it, by digestion, a portion of sulphur generally using about a teaspoonful of sulphur, in flour, to a quantity of oil of turpentine which is to dissolve a pound of India-rubber; the exact proportion not being important, and that indicated being sufficiently near for practical purposes. With this solution I proceed as with the ordinary spirits of turpentine. Instead of making this solution of sulphur, I sometimes use the flour of sulphur, or sulphur in fine powder, and incorporate it in the proportion above indicated with the gum when brought to a pulpy mass by any of the common solvents, or when worked by heated cylinders without any solvents, taking care that it is intimately mixed with the mass. Another mode of using the sulphur is to apply it to the surface of the gum after it has been applied to the cloth, or rolled into sheets, causing it to adhere by pressure or otherwise. After which the gum is to be submitted to the action of metallic salts, in the manner described by Charles Goodyear. The effect of the sulphur in whatever way it may be added to the gum, is to cause it to dry more perfectly, and to improve the whole substance thereof, rendering it much superior to that prepared by any other combination therewith. The subsequent process of curing, or tanning, the surface above referred to, as patented by Charles Goodyear, removes all the odor of sulphur, and is intended to be generally applied to all articles manufactured as above. What I claim as my invention, and desire to secure by letters patent, is the combining of sulphur with gum elastic, whether in solution or in substance, in either of the modes above pointed out, or in any other that is substantially the same, and which will produce a like effect.