Sir William Crookes, English physicist and chemist, 1914.

UNITED KINGDOM - SEPTEMBER 09: Signed portrait photograph. After studying at the Royal College of Chemistry in London, Crookes (1832-1919) went on to make significant contributions in several fields of science. He invented the radiometer (1873-1876), a device that responds to light or other electromagnetic radiation (which led to research in vacuum physics), and the spinthariscope (1903) which made individual alpha particles visible. He also discovered the element thallium, and was an authority on sanitation and agriculture. (Photo by SSPL/Getty Images)