Gummi
Natural rubber is an elastomer (an elastic hydrocarbon polymer) that originally was derived from "latex", a milky colloidal suspension found in specialised vessels in some plants. It is useful directly in this form (indeed, the first appearance of rubber in Europe was cloth waterproofed with unvulcanized latex from Brazil). However, in 1839, Charles Goodyear invented vulcanized rubber: a form of natural rubber heated with sulfur (and a few other chemicals), forming cross-links between polymer chains (vulcanization), improving elasticity and durability. In 1851, Nelson Goodyear added fillers to natural rubber materials to form ebonite.