Chance's Crookes glass plano tint B2 lens in packet

Historical Significance: This kind of lens was the precursor to sunglasses. Crookes glass is type of glass that contains cerium and other rare earths and has a high absorption of ultraviolet radiation. It was developed by Sir William Crookes, OM, FRS (1832 -1919), a British chemist and physicist who researched on spectroscopy. He was a pioneer of vacuum tubes, inventing the Crookes tube. After the inclusion of a number of industrial diseases and injuries in the Workmen's Compensation Acts of 1896 and 1906, the government asked the Royal Society to investigate how and why glare and heat apparently caused glassworkers to develop cataracts during their working lives. The activities between 1908 and 1928 of the Glass Workers' Cataract Committee are described in a paper by W H Brock [The Royal Society's Glass Workers' Cataract Committee; Sir William Crookes and the development of sunglasses doi: 10.1098/rsnr.2007.0184 Notes Rec. R. Soc. 22 September 2007 vol. 61 no. 3 301-312] The committte was made up of chemists, physiologists and ophthalmologists and the paper discusses the attempts by the octogenarian William Crookes to formulate a spectacle glass that was opaque to infrared and ultraviolet radiation. While providing relief for industrial workers, the research also laid the foundation for the modern sunglasses industry. Chance Brothers and Company was a glassworks originally based in Spon Lane, Smethwick, West Midlands (formerly in Staffordshire), in England. It was a leading glass manufacturer and a pioneer of British glassmaking technology from 1824 until 1952 when Pilkington's took control of the company and assumed management control in the late 1960s. See also Cat No 2446