Psychical researcher and president of the Society for Psychical Research (SPR). Sidgwick was born on March 11, 1845, the older sister of Arthur James Balfour (later British Prime Minister Premier) and Gerald William Balfour, both of whom were also elected president of the SPR. In 1876 she married Henry Sidgwick, who would go on to become a professor of moral philosophy at Cambridge and in 1882 the first president of the SPR. Though without formal training, she was of great intellect and began to participate in research alongside her husband. Her sister Evelyn Balfour married John William Strutt (Lord Rayleigh), also an SPR president.
Mathematics was her forte. With her brother-in-law Lord Rayleigh, she conducted several experiments in electricity and with him published three papers in the Philosophical Transactions of the Royal Society. Lord Rayleigh later won the Nobel Prize for physics.
She joined the SPR, and in 1888 she assumed the duties formally assigned to her husband as editor of the society's Journal and Proceedings. In the 1890s, deemed the best at handling large masses of information, she was placed in charge of the Census of Hallucinations and was the author of the final report. She was elected president of the SPR for 1908-09. After her term of office was finished, she acted as honorary secretary until 1931. At the society's Jubilee Celebrations in 1932, she was appointed as President d'Honneur. Over a 30 year period she collected and analyzed the many communications that made up the bulk of the cross-correspondences.
Over the years she wrote a number of papers for the Journal and Proceedings of the SPR. She assisted Edmund Gurney, F. W. H. Myers, and Frank Podmore in the compilation of their key work Phantasms of the Living (2 vols., 1886) and edited an abridged edition in 1918. She also contributed the entry on Spiritualism to the 9th edition of the Encyclopedia Britannica (1875-89). She died February 10, 1936.
Sources:
Berger, Arthur S., and Joyce Berger. The Encyclopedia of Parapsychology and Psychical Research. New York: Paragon House, 1991.
Gauld, Alan. The Founders of Psychical Research. New York: Schrocken Books, 1968.
Pleasants, Helene, ed. Biographical Dictionary of Parapsychology. New York: Helix Press, 1964.
Sidgwick, Eleanor. "Discussion of the Trance Phenomena of Mrs. Piper." Proceedings of the Society for Psychical Research (1899).
——. "An Examination of Book-Tests Obtained in Sittings with Mrs. Osborne Leonard." Proceedings of the Society for Psychical Research (1921).
——. "Hindrances and Complications in Telepathic Communication." Proceedings of the Society for Psychical Research (1923).
——. "History of the SPR." Proceedings of the Society for Psychical Research (1932-33).
——. "Phantasms of the Dead." Proceedings of the Society for Psychical Research (1885).
——. "The Physical Phenomena of Spiritualism." Proceedings of the Society for Psychical Research (1886).
