Eleventh, to A. L. Van Horn, Philadelphia, Pa., June 26, 1835, India-rubber webbing for riding-saddles.
Twelfth, to Charles Goodyear, New Haven, Conn., Sept. 9, 1835, for India-rubber cement.
Thirteenth and Fourteenth to William Atkinson, New York, Oct. 6, 1835, for cutting India-rubber into threads; also, another patent same date, for spreading and drying India-rubber upon cloth.
Fifteenth, to Patrick Mackie, New York, March 23, 1836, for dissolving India-rubber in naptha and sulphate of zinc.
Sixteenth, to Ranson Warner, New York, May 18, 1836, for manufacturing gum-elastic suspenders.
Seventeenth, to E. M. Chaffee, Roxbury, Mass., May 31, 1836, for India-rubber application to cloth. Mr. Chaffee obtained another patent in August, 1836, for softening India-rubber and applying it to cloth, without dissolving it, by pressing it between heated rollers. This was and is, a very important patent. It is not reported in the United States Patent Reports, and the reason for its suppression is variously accounted for.
Eighteenth. Specification of a Patent for divesting caoutchouc or India-rubber of its adhesive qualities, and also of bleaching the same, and thereby adapting it to various useful purposes. Granted to Charles Goodyear, New York City, June 17th, 1837.
Mr. Goodyear claims the discovery of a new and improved mode or process of divesting caoutchouc, gum elastic, or India-rubber, of its adhesive properties. I employ the various acid solutions of the metals, and with such metallic solution I wash over the surface of the caoutchouc, of which I mean to destroy the adhesive property; or instead of washing the surface of the caoutchouc, I dip it, or the article coated with it, into such a solution. * * *
The metallic solutions are not, by any means, equally effective in destroying the adhesiveness of the caoutchouc; the stronger acids being in all cases preferred, as being perfect in their action, nor is it indifferent what kind of metal is employed. The strong nitric acid, undiluted, is that which I in general prefer; and among the metals, I prefer either copper or bismuth, forming a nitrate of copper, or a nitrate of bismuth, as the full effect is produced by these solutions in from one to five minutes. After the action is thought to be complete, the article acted upon is to be washed with water, so as to remove the whole of the acid solution, and it will be found that not only the surface of the caoutchouc will resemble that of a soft cloth, but that the surface may be worn off to a considerable depth, and the new surface not manifest the slightest tendency to adhesiveness; it is indeed so far altered in its properties as to resist, to a considerable extent, the action of those menstrua by which it is ordinarily dissolved. It may, for example, be washed in spirits of turpentine, or in the oil of sassafras, without being rendered sticky; and it will equally resist the action of solar or of artificial heat, under all ordinary temperatures.
I have sometimes covered the surface of the caoutchouc with the metallic powder known by the name of bronze, and have afterwards washed it over with nitric acid, which has produced the same effect as the washing it with, or dipping it in the metallic solution, such a solution being in this case immediately produced by the action of the acid upon the metal. It is a common practice to add some of the absorbent earths, or some pigment, to the dissolved caoutchouc, and when this is done the metallic solution may be readily made to operate to a greater or less extent throughout the whole mass of a sheet of considerable thickness.