_Seventh._ In the dry or solid state it is flexible, of great tenacity, and to a slight degree elastic. _Eighth._ It is impermeable to, and not injuriously affected by atmospheric air. _Ninth._ It is, in a pure state, nearly inodorous. _Tenth._ _It is little, if at all injured by use_, (except as fuel), and may, after it has been employed in a manufactured state, be recovered or renovated, and manufactured anew. In some of these properties, namely, its adhesive, and water and air repellent properties, gutta-percha resembles caoutchouc, or India-rubber, but it is advantageously distinguished from it in its freedom from stickiness when dry, in its not being so affected by atmospheric heat, or by unctuous oils, and in its being _workable by means of hot water alone_. [The patentee then described how this substance may be applied, either by itself, or in combination with other materials.] 1st. _Artificial Fuels._—Five different sorts are described, the peculiarity in all of which consists in the substitution of the gutta-percha, in different forms or proportions, for the coal tar, or other agglutinizing substance ordinarily employed. 2d and 3d. Artificial _mastics and cements_. The gutta-percha is directed to be first freed from the fibrous and foreign matters with which it is usually found intermixed, when first imported, after which it is to be applied in any one of the three states, namely, 1st, a plastic state; 2d, a granular or pulverized state; and 3d, a state of solution. PLASTIC APPLICATIONS. The kneading machinery is similar to that used in the manufacture of rubber. When it is desired to give to the mass of gutta-percha a greater degree of elasticity than is natural to it, I mix up and incorporate with it, while it is going through the kneading machine, either a portion of caoutchouc or a portion of sulphur, or portions both of caoutchouc and sulphur.