William Crookes

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William Crookes was a British chemist and physicist whose scientific reputation was already secure when, in the early 1870s, he turned the methods of the laboratory on the séance room and announced that something there resisted ordinary explanation. The collision of those two careers — discoverer of the element thallium and fellow of the Royal Society on one side, examiner of mediums on the other — made him one of the most discussed figures in the Victorian quarrel over whether the spiritualist phenomena were real.

His standing as a scientist was not in doubt. He discovered thallium in 1861, isolating the metal soon after, built the radiometer that still turns in shop windows, devised the high-vacuum tube that carries his name and prepared the ground for the study of cathode rays, edited the Chemical News, and was in time knighted and elected president of the Royal Society. It was from inside that authority, not outside it, that he took up the mediums — which is precisely what unsettled his contemporaries.

Between roughly 1870 and 1874 Crookes conducted sittings with the medium Daniel Dunglas Home and with the young Florence Cook, who claimed to materialise a spirit called Katie King. He weighed, measured, and instrumented what he could, reporting movements of objects and variations in weight that he held no known cause would produce, and proposed the existence of a “psychic force” answerable to investigation. Critics charged that he had been deceived, that the controls were loose, and — in the Cook case especially — that the arrangement invited collusion; the suspicion has shadowed his reputation ever since, without ever being settled to anyone’s full satisfaction. What can be established is the record of the experiments and the resistance they met, not a verdict on the phenomena themselves.

Crookes did not present himself as an occultist or adept. He framed the work as inquiry: the spiritualists held that the dead communicated, while he claimed only to have observed effects he could not account for and to have followed them where the evidence seemed to lead. He helped found the Society for Psychical Research and served as its president, lending the new field the same name that lent weight to British chemistry. Later in life his interests touched the theosophical and the spiritualist currents of the day, though he kept his public case narrower than his sympathisers wished.

His significance to the esoteric record lies less in any doctrine than in the spectacle of a first-rank scientist insisting that the question deserved investigation rather than dismissal. That insistence cost him, and it was never vindicated; it also kept open, for a generation, the possibility that the line between the measurable and the marvellous had been drawn too soon.

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