Discovery Lab Answers

William Crookes: Experiments and Data

Who Crookes Was and What He Investigated

William Crookes (1832–1919) was a Fellow of the Royal Society and editor of the Quarterly Journal of Science — credentials that made his turn toward psychical research both notable and controversial. Between roughly 1871 and 1874 he published a series of reports on physical mediumship, gathered under the title Researches in the Phenomena of Spiritualism, reprinted from the Quarterly Journal of Science ^[1][2]. His principal subjects were the medium D. D. Home, Annie Eva Fay, and Florence Cook.

The Core Experimental Claims

Crookes’s most technically detailed work concerned D. D. Home and what he called “psychic force” — an apparent ability of Home to affect physical objects without contact. The flagship apparatus was a lever-and-balance arrangement: a mahogany board was placed so that one end rested on a fixed support and the other was suspended by a spring balance, with a water vessel sitting on the board. The question was whether Home could register a change in the spring-balance reading without touching the board in a way that could account for the effect mechanically.

Crookes recorded deflections on this instrument and noted that the results formed a curved line on the recording apparatus, from which tension readings at any moment could be calculated ^[3]. He submitted the manuscript to the Royal Society in June 1871, whereupon Professor G. G. Stokes, Secretary of the Royal Society, raised technical questions about the experimental setup — questions Crookes acknowledged and engaged with in published correspondence ^[1][2][3].

A force-calculation Crookes published in response to a critic argued that to produce the observed lever deflection by direct mechanical action, Home would have had to exert approximately 74.5 lbs of force while seated in a low easy chair — a figure Crookes offered as a reductio against the skeptical hypothesis ^[1][2]. The retrieved excerpts show this calculation clearly enough to report the figure, though the surrounding OCR text is partially damaged and readers wanting the full derivation should consult the primary source directly.

Crookes explicitly declined to attribute the effects to any particular cause: “The experiments appear to me to show the importance of further investigation, but I wish it to be understood that I express no opinion as to the cause of the phenomena which took place” ^[1] — a position he maintained into his 1898 Presidential Address to the British Association, where he did not retract his earlier findings ^[4].

Witnesses and Corroboration

Crookes’s reports were not produced in isolation. The astronomer William Huggins (also F.R.S.) was present at some sessions and provided a letter confirming what he had witnessed, which Crookes published ^[1]. A sitting examining Mrs. Annie Eva Fay’s mediumship reportedly included figures such as Crookes, Galton, Huggins, and others described in the record as “a distinguished company” ^[4]. Crookes published these testimonials alongside his own accounts as part of his evidential strategy.

The Florence Cook / “Spirit Forms” Investigations

The 1874 section of the pamphlet addresses spirit forms — full-figure materializations Crookes claimed to have observed and photographed through the medium Florence Cook. In a February 1874 letter, Crookes asked readers not to assume that everything “prima facie suspicious necessarily implies deception” and promised further reporting ^[1][2]. The Volckman incident — in which a skeptical observer attempted to physically seize the materialized form during a sitting in December 1873 — formed a contested backdrop to these claims, documented in the Medhurst and Goldney review ^[4].

The Medhurst and Goldney Scholarly Review

Medhurst and Goldney (1964) in the Proceedings of the Society for Psychical Research conducted a detailed scholarly examination of Crookes’s physical-phenomena investigations, including the Cook sittings ^[4]. Their work, commissioned in part through the research of Mostyn Gilbert, is the primary critical-scholarly treatment in the sources retrieved for this question. The Medhurst and Goldney paper also reproduces Crookes’s examination of Mrs. Fay’s mediumship, situating it within the broader record of his investigations.

Skeptical Critiques

What critics argue. The most direct critique in the retrieved sources comes from T. H. Hall’s The Medium and the Scientist (1962, republished 1984 as The Spiritualists) ^[3][4], which argued that Crookes’s relationship with Florence Cook compromised the objectivity of the Cook investigations. The Volckman incident — where an observer reportedly seized the materialized “Katie King” and found it to be Cook herself — was cited by Hall and others as evidence the phenomena were fraudulent and that Crookes had been deceived or was complicit. W. B. Carpenter, F.R.S., publicly challenged Crookes’s competence and methodology in the early 1870s, prompting a published correspondence exchange in which Crookes accused Carpenter of misrepresenting his informants and demanded retraction ^[1][2].

The Royal Society declined to publish Crookes’s original “psychic force” paper, and Stokes’s technical objections — concerning whether the spring-balance apparatus adequately controlled for mechanical artifacts — formed the basis of an institutional-level skeptical response ^[3].

Ishida (2012) in the Journal of Scientific Exploration reconstructed the lever experiment using mechanical modeling, including a sloshing-force analysis of the water vessel, to assess whether mundane physical causes could account for the recorded deflections ^[3]. Ishida’s paper characterizes the rejection of Crookes’s work as involving what it terms “systematic errors in sciences” — the paper’s framing is sympathetic to Crookes — but the mechanical modeling it introduces gives quantitative form to the question of whether the apparatus was adequately controlled.

What the experimental data show. Crookes’s published calculations argued the lever deflections could not have been produced by Home’s body position alone, given the geometry and the 74.5 lb figure ^[1][2]. Independent witnesses including Huggins were present at some sessions and attested to the phenomena ^[1]. Medhurst and Goldney’s 1964 review, working from original documents, did not simply dismiss the record but engaged with it as a scholarly matter, reproducing previously unpublished Crookes texts ^[4].

Analysis. No independent replication of the specific lever-and-balance protocol by a researcher unconnected to Crookes’s circle has been published in the sources retrieved for this question. The Cook materializations rest almost entirely on Crookes’s own testimony and photographs, with the Volckman incident introducing a documented competing account. The Carpenter dispute illustrates that methodological objections were raised contemporaneously, not only in retrospect. Ishida’s mechanical modeling (2012) represents the most technically detailed modern engagement with whether the apparatus design was adequate, but it appears in a single paper rather than a replicated program of work.

Historical Context

Rosemarie Pilkington’s The Spirit of Dr. Bindelof situates Crookes’s investigations within the longer history of physical mediumship — from D. D. Home through Eusapia Palladino and Indridi Indridason — treating them as a documented chapter in a tradition that later laboratory researchers sought to connect to more controlled paradigms. The ESP-Nexus page on that book is at The Spirit of Dr. Bindelof.

The ESP-Nexus study-audit page for the 1874 pamphlet itself is at Crookes (1874), where the document’s provenance — an OCR extraction of a scanned 1874 J. Burns pamphlet, digitized in 2010 under Open Knowledge Commons and Harvard Medical School funding — is documented in full.