Throughout the later 19th century, many chemists attempted to determine the makeup of natural rubber, with the goal of reproducing it. In 1860, Williams analyzed rubber by destructive distillation and obtained a large quantity of a light oil which he termed isoprene (polymer of the monomer isoprene—formula CH2:C(CH3)CH:CH2). Many efforts were made during the next 70 years to synthesize rubber in the laboratory by using isoprene as the monomer, but these did not bear fruit until Samuel Horne succeeded in 1955.