Sir William Crookes was one of the most distinguished experimental scientists of Victorian Britain, the discoverer of the element thallium, the inventor of the radiometer and of the vacuum tube that carries his name, and a president of the Royal Society. He was also, from 1870, a public investigator of Spiritualist mediums, and he published reports claiming that the medium Daniel Dunglas Home could alter the registered weight of a board and cause an accordion to sound while it was locked inside a cage of his own construction. His scientific colleagues were, with few exceptions, appalled, and the episode became the standard example of how far specialist eminence fails to transfer to a domain in which the object of study may be actively deceiving the observer. His sittings with the young medium Florence Cook attracted particular suspicion, then and since. Crookes never retracted, and continued a distinguished career in chemistry and physics for another forty years.
Facts
Disputed
Key ExperimentThe spring-balance board and the caged accordion, built for sittings with Daniel Dunglas Home between 1871 and 1873 and reported in the Quarterly Journal of Science 1 William Crookes's Researches in the Phenomena of Spiritualism (J. Burns, 1874) reported Crookes's own laboratory measurements, using a device of his own design intended to detect and quantify a physical force from mediums under test conditions, of apparent psychic force exerted by mediums including Daniel Dunglas Home. No other scientist has ever replicated Crookes's specific measured results, and Crookes himself, despite his critics' specific requests that he repeat the measurements under more tightly controlled conditions designed to rule out the objections raised against his original setup, did not do so; he also never retracted or revised his original published conclusions in light of that unmet challenge. Origins
Place of Origin Open Questions
Principal CriticLater writers have argued that the sittings with the young medium Florence Cook involved collusion or a personal relationship 2 No documentary proof has been produced in either direction. The allegation rests on circumstantial readings of Crookes's own published accounts and on later recollection, and no correspondence or household record has been produced that settles it. Life
Lifespan or Floruit Learn More
The Chemist Who Built the Apparatus
Crookes's scientific credentials were not marginal. He identified thallium in 1861 from a green line in a spectrum, built the radiometer whose vanes still spin in shop windows, developed the high-vacuum tube that bears his name and that led directly to the discovery of the electron and of X-rays, and was elected to the Royal Society at thirty-one and eventually to its presidency. When he turned to Spiritualism in 1870 he did so in the manner of an instrument builder, announcing that the question could be settled by measurement and constructing the equipment to do it.
For the sittings with Daniel Dunglas Home he suspended a mahogany board with one end resting on a fulcrum and the other on a spring balance, so that any downward force could be read off a scale, and he reported deflections while Home's fingers rested lightly at the fulcrum end where they could exert no leverage. For the accordion he built a wire cage under the table, placed the instrument inside it, and reported that it played while Home held it by the end away from the keys. The apparatus was good. Whether the protocol around it was is the whole question. A balance reads whatever force is applied to it, and it cannot report who applied the force or by what route, which is the gap the whole controversy occupies.
Why Eminence Did Not Transfer
The reaction of Crookes's colleagues was severe and the reasoning behind it has held up. A first-rate experimentalist is trained against one kind of error, the error of a badly designed measurement, and nature does not adapt to defeat the apparatus. A seance does. The sittings were held in Crookes's own house but on terms the medium influenced, with the lighting, the seating and the timing arranged as he preferred, and the reports do not record the kind of controls a conjuror would have insisted on. The sittings with Florence Cook, a young medium who produced a full-form materialised figure called Katie King, drew the most suspicion, since Crookes vouched for her at length and the figure was never observed simultaneously with the entranced medium under conditions that excluded the obvious explanation.
Later writers, from the 1960s onward, have argued that Crookes was either complicit or personally involved with Cook; the evidence offered is circumstantial and the charge is not established. What is established is that no scientist replicated his results, that he did not repeat the measurements under conditions his critics specified, and that he never withdrew the reports. He was knighted in 1897 and became president of the Royal Society in 1913, which tells you how completely Victorian science was able to hold the two halves of his career apart.
Cross-Tradition Connections
Associated With
This source names William Crookes directly: "taken for the physicist and chemist William Crookes, who investigated the medium Florence Cook and the figure calling herself Katie King, said to materialize at Cook's seances."
Elected a fellow in 1863, knighted in 1897, and president of the society from 1913. His standing in chemistry and physics was never in question; his psychical work was rejected by his colleagues.
William Crookes controversially investigated psychic claims under its shadow.
Studied
William Crookes investigated her 1874 sittings and published an endorsement of the phenomena as genuine
Why this is disputed. William Crookes sat repeatedly with the medium through whom Katie King was said to materialize, photographed the resulting figure, and published his conviction that medium and materialization were two physically distinct people in the room at once. His experimental controls, including how closely the medium was searched and confined before each sitting, were criticized by contemporaries as inadequate to rule out the figure being the medium herself in costume, and that criticism has been repeated by later historians of psychical research, so Crookes's own conclusion remains a minority position against a historiography that treats the case as unresolved at best and as demonstrated fraud at worst.
Sources
Open Questions (1 open question)
Did William Crookes's sittings with the medium Florence Cook involve collusion or a personal relationship?
Writers since the 1960s have argued that Crookes either knew the materialisations were produced by Cook herself or was personally involved with her, and that this explains his willingness to vouch for phenomena he would have tested rigorously in any other setting. The arguments rest on circumstantial reading of his published accounts and on later recollection, and no documentary proof has been produced in either direction.
What would resolve this Contemporary correspondence between Crookes and Cook, or household records establishing the arrangements at the sittings, if any survive in family or institutional archives.
History of Victorian science; archival researchRuth Brandon, The Spiritualists: The Passion for the Occult in the Nineteenth and Twentieth Centuries
Reader Challenges (0 open reader challenges)
No disputes yet. Spotted an error or a better source? Open the first one.
Sign in to dispute this or suggest a correction.
View At A Past Year
The atlas records no dated fact of its own for this entry, so there is no other year to choose.