The adaption of rubber to industrial purposes such as the manufacture of shoes, physical and surgical appliances, elastic cloths, railway-buffers, machine-springs, etc., was fairly in full swing when the discovery of the vulcanizing of rubber by Goodyear sprung up, an occurrence which came to revolutionize the incipient industry and enormously enlarge the scope of the commercial application of that product, which thence forward came to assume exceptional importance. The vulcanizing method consists in the mixing of a certain quantity of rubber with sulphur and in the exposure of that mixture to an elevated temperature and to a high pressure during a certain space of time. The rubber transforms itself considerably; the property of indefinite hardness is lost, but presents greater resistency to the forces of compression and lengthening-out, supports excessively low temperature and becomes less sensible to the action of ordinary dissolving ingredients. In Brazil already existed up to 1840, a rudimentary industry of shoe manufacturing and in the water-proofing of various objects. The great demand for rubber caused by the development of the industry in foreign countries and consequently the very high profits that the extraction of rubber in the Brazilian “seringaes” or native rubber-forests presented, destroyed all that initiative and Brazil passed into the position of a mere producer of the raw material. In order to appreciate with what devotion the country lent itself to this occupation, sufficient is it to contrast the 31 tons exported in 1827 with the 36,547 exported in 1911. [Illustration: DR. EUGENIO DAHNE, General Secretary of the Federal Government of Brazil Commission.] RUBBER-PRODUCING PLANTS—BOTANICAL DESCRIPTION—PRODUCTIVENESS—REGIONS IN WHICH THEY EXIST At the present moment, more than 300 species of rubber-producing plants are known to exist, these being distributed among the tropical regions of the world. Trees of large size, climbing plants and flexible creepers containing the precious latex in their branches, trunk and roots, those vegetable growths from the double point view of quantity and quality of rubber produce have not an equal importance. The species worthy of mention belong to four great families: 1.—Euphorbiacan, =Hevea=, =Micrandra=, =Manioh=. 2.—Ulmacean, =Castillôa= and =Ficus=. 3.—Apocynacean, =Landolphia=, =Hancornia=, =Kickxia=, =Carpodium= and =Clitandra=. 4.—Asclepiadaceas, =Callotropia=, =Cynanchum=. The production of rubber in America is principally furnished by the heveas, micandra, manioh, castillôa and hancornia; that of Asia by the ficus; and that of Africa by the landolphia, clitandra and kickxia.