One of England’s outstanding scientists who during the early years of his career became involved in psychical research and with one of the most controversial mediums of modern spiritualism, Florence Cook. After graduating from the Royal College of Chemistry, he went to work in the Meteorological Department at Radcliffe Observatory. His first major contribution was the discovery of the element thallium in 1861. He was elected to the Royal Society two years later. Crookes invented the spinthariscope, the radiometer, and the Crookes tube (which allowed the study of cathode rays). He founded the Chemical News and the Quarterly Journal of Science. In acknowledgment of his scientific accomplishments, he was awarded the Royal Gold Medal (1875), the Davy Medal (1888), and the Sir John Copley Medal (1904). He was knighted in 1897, received the Order of Merit (1910), and served a term as president of the Royal Society.
Crookes became interested in spiritualism following the death of his brother in 1867. He had some preliminary sittings with various mediums prior to his announcement in 1870 that he would begin a study of spiritualist phenomena. Crookes first investigated Daniel Douglas Home and became convinced that his levitation and related psychokinetic phenomena were caused by a psychic force. Beginning in December 1873, Crookes worked with Florence Cook, a materialization medium. At one point he had himself photographed with “Katie King,” the entity who materialized in the seances. He wrote glowingly of what he had experienced at these seances and defended Cook against charges of fraud. Crookes also conducted a series of studies with the American medium Annie Eva Fay. He then dropped further psychical research and turned his attention to the work that later brought him so much fame and honor.