Note 38 — Chapter XI

The process of vulcanizing was made practicable during the ten years ending in 1850. It was invented and perfected by Goodyear in the United States and by Hancock in England; for ordinary purposes, where both strength and elasticity are required, about five per cent. of sulphur is added. The addition of about fifty per cent. changes the rubber to a hard black substance known as "ebonite," or "hard rubber."