We may mention here a characteristic of Mr. Goodyear’s inventive genius. He considers failures as stepping-stones to success. He tells one of the many well selected aids by whom he is surrounded, to do such and such a thing. The mechanician returns after giving his earnest attention to the task, with a something so clumsy or so ridiculous that it either raises the fear of censure or the dread of laughter as the reward of his pains; but neither laughter or censure await him. The result is just what its originator expected; the practical application confirms his views. A dozen failures, perhaps fifty, perhaps two hundred, wait upon these efforts, but with this valuable difference, that each failure approaches, directly or indirectly, the something that the mind desired to arrive at. Thus, each thing is, as it were, hemmed in; it is check-mated by these far-seeing moves, and science, the antagonist in this noble game, renders up the coveted object of an intellectual struggle. In a word, it is a practical exercise of inductive philosophy, or the algebra of mechanics getting at positive and useful facts by means mysterious and unintelligible to ordinary comprehensions. CHAPTER III. VULCANIZATION. Camphine or turpentine, oil of sassafras, and all the essential oils, are faithful tests of the quality of gum elastic, and as certain in their tale-telling as nitric acid is of the genuineness of gold. As the native gums, and also the common manufacture of gum elastic have the same general appearance as those that are vulcanized, more particularly to persons not acquainted with the manufacture nor judges of the goods, these tests are of the utmost importance, not alone to determine whether the goods are genuine, but also to ascertain whether those that are vulcanized are properly done. When these tests are applied to any fabric of native gum, it is rendered very adhesive, and so quickly as to destroy any light fabric almost immediately, while upon goods that are well vulcanized, they should have no such effect. If they do so the manufacture is bad. Although the manufacture of hard India-rubber goods, by the process of vulcanizing, is extensively known and appreciated in the United States, and in France and Belgium, very little appears to be understood in Great Britain. Indeed, in Birmingham, which is justly termed the “work-shop of the world,” little or nothing, or if anything, a something amounting to a misunderstanding, would comprise the quantity of intelligence upon the subject. There can be little doubt, however, that as the infinite capabilities of the material become known, and justly esteemed, and its amazing applications get manifested, no one thing of late years, surprising as the changes have been in that neighborhood, will have caused so great a revolution in very many of the staple manufactures of that town as will the introduction of this discovery.