BAKER, Circuit Judge

(after stating the facts as above). [1] Is appellee’s process within the teachings of the patent? In Muller’s *599disclosure tlie first step is to take mineral pitch, or its equivalent, and dissolve it preferably “at about normal temperature” in a volatile solvent, such as benzol, or its equivalent. While heat in this first step is not excluded, the patent very clearly contemplates that the bituminous material and the volatile solvent shall be of such a character that a solution will result from their being put together without extraneous heat. Tn other words, if heat is to be used at all, it would be only for the purpose of talcing somewhat more quickly a step that could he taken without the use of heat. At the next step the fire-resisting material, such as asbestos, or its equivalent, is mixed into_ the solution until a consistent plastic mass is formed. This plastic mass is then placed in molds and subjected to heavy pressure “preferably in a cold state.” And the final step is thus prescribed in the specification :

"Tlie volatile ingredient of tile compressed product is permitted to evaporate therefrom hy exposure to air. whereupon the product is hardened by the evaporation of the solvent. If desired, the compressed mass may be subjected to heat for the purpose of hastening the evaporation.”

Thus an examination of the' patent makes manifest that Muller’s process, in what he declared the most desirable way of practicing it, consisted in a succession of steps each of which was to- he taken at normal temperature.

In tlie trial court oral testimony of experts Was heard with regard to the results obtained by practicing the teachings of the patent. The trial judge found, and we also find, that the undisputed evidence demonstrates that the Muller process, practiced according to the teachings and disclosures of the patent and by persons both learned and skilled in the production of plastic compositions for insulating materials, produced a product which, after exposure to the air for more than a year, could be distorted by hand, was readily soluble in benzol, and when exposed to the flame of an alcohol lamp gave off visible vapors in 5 seconds, ignited in 30 seconds and crumbled in 45 seconds; and that such a product was valueless as an insulating material.

Undisputed expert testimony discloses that “a volatile solvent is one that boils at a temperature below the boiling point of water.” 'Phis is true of benzol; but it is not true of the light coal-tar oil in which appellee dissolves the already molten pitch by means of heat, and without the use of heat this first step of appellee’s process would be commercially impossible. The subsequent addition of benzol is necessary to thin the mixture so as to offset the coagulating tendency of die china-wood oil. And when the asbestos has been mixed in and the composition has been screened and placed on trays to dry, the benzol entirely evaporates from the granular mass, and not from the molded article as in the process of the patent. In appellee’s process heat is absolutely necessary in order to bring about the rubberization of the china-wood oil. Furthermore,’ the final subjection of the molded article to heat is essential for, the expulsion of the light coal-tar oil in which the molten pitch was primarily dissolved, and finally the prolonged subjection to the increasingly high degree of heat in a closed oven is requisite to the hardening and the rendering unin*600flammable of the finished product by volatilizing and driving off the heavier oils that remain in commercial pitch and which volatilize at from 500° to 600° Fahrenheit.

Appellant learned to make “Gummon” from Muller in a factory in Germany. If Muller, when he wrote the specification of his patent, had already developed the “Gummon” process, in which the anthracene or other heavy coal-tar oil is not vaporizable without a high degree of heat and in which the non-vaporizable residue of the anthracene oil acts somewhat in the finished product as china-wood oil does in appellee’s product, he carefully refrained from giving the necessary recipe for making the product; and if the process claims in suit have any vitality, if the patent for the process is not void on account of vagueness and inadequacy of disclosure (Western Electric Co. v. Ansonia Co., 114 U. S. 447, 452, 5 Sup. Ct. 941, 29 L. Ed. 210), we are quite convinced that appellee does not infringe.

[2] Though claims for a new product which has definite characteristics by which it may be identified and which distinguish it from the process by which it is made, are not limited to the product as made under the disclosed process (Rubber Co. v. Goodyear Co., 9 Wall. 796, 19 L. Ed. 566; Hide-ite Leather Co. v. Fiber Co., 226 Fed. 34, 141 C. C. A. 142), nevertheless product claims are not sustainable unless the specification discloses at least one practicable way in which to make the product.

The decree is affirmed.