Parkes, Alexander

Alexander Parkes, (born Dec. 29, 1813, Birmingham, Warwickshire, Eng.—died June 29, 1890, West Dulwich, London), British chemist and inventor noted for his development of various industrial processes and materials.

Much of Parkes’s work was related to metallurgy. He was one of the first to propose introducing small amounts of phosphorus into metal alloys to enhance their strength. One of his most significant inventions was a method of extracting silver from lead ore. This procedure, commonly called the Parkes process (patented in 1850), involves adding zinc to lead and melting the two together. When stirred, the molten zinc reacts and forms compounds with any silver and gold present in the lead. These zinc compounds are lighter than the lead and, on cooling, form a crust that can be readily removed.

Another of Parkes’s important contributions was the discovery of the cold vulcanization process (1841), a method of waterproofing fabrics by means of a solution of rubber and carbon disulfide. Parkes also produced a flexible material called Parkesine (1856) from various mixtures of nitrocellulose, alcohols, camphor, and oils that predated the development of the first plastic, celluloid.