Alexander E. Outerbridge, Jr., A Fourth State of Matter. Lecture delivered before the Franklin Institute, 17 February 1881. Journal of the Franklin Institute of the State of Pennsylvania, Volume 81. By Franklin Institute (Philadelphia, Pa.). Page 287+ (頁面存檔備份,存於網際網路檔案館).
The difference between "Crookes tubes" and "Geissler tubes" is this: In a Geissler tube the exhaustion is very much less than in a Crookes tube, the light which we see in the Geissler tube being due to the luminescence of the residual gas. (Transactions, Volume 9. Hertfordshire Natural History Society and Field Club. The Club, 1898. Page 136 (頁面存檔備份,存於網際網路檔案館).)
William Crookes, On Radiant Matter. Lecture delivered before the British Association for the Advancement of Science, at Sheffield, Friday, 22 August 1879. The Popular Science Monthly, Volume 16. D. Appleton, 1880. Pg157+ (頁面存檔備份,存於網際網路檔案館)
Radio-activity induced by the oscillatory discharge, or, The subsequent radio-active emanation from substances exposed to the Tesla oscillatory discharge. Harry Marshall Diemer, Ralph Stuart Cooper. Cornell University, 1903. Page 43+ (頁面存檔備份,存於網際網路檔案館).
Janet Oppenheim. (1988). The Other World: Spiritualism and Psychical Research in England, 1850-1914. Cambridge University Press. pp. 343–347. ISBN978-0521265058
John Hannavy. (2007). Encyclopedia of Nineteenth-Century Photography. Routledge. p. 350. ISBN978-0415972352 "Crookes' beloved younger brother had died in 1867 and the scientist hoped that spiritualism could provide a reunion. Although warned of the risk of ridicule, Crookes announced his intent to investigate mediums."
Sherrie Lynne Lyons. (2010). Species, Serpents, Spirits, and Skulls: Science at the Margins in the Victorian Age. State University of New York Press. p. 92. ISBN978-1438427980 "Crookes appears to have been initially attracted to spiritualism when his youngest brother, whom he was quite close to, died of yellow fever. Brought up with the traditional Christian belief in the afterlife, Crookes was persuaded to attend a séance in 1867 to try to make contact with his brother."
Martyn Jolly. (2006). Faces of the Living dead: The Belief in Spirit Photography. Miegunyah Press. p. 30. ISBN978-0712348997 "In 1867, he was devastated by the death of his much-loved youngest brother who, at the age of twenty-one. had caught yellow fever while laying a submarine telegraph cable in Cuba. At the time, Crookes was collaborating with a fellow electro-physicist Cromwell Fleetwood Varley, who was a pioneer of intercontinental telegraphy, as well as a clairvoyant. He persuaded Crookes to try to get in touch with his dead brother by spiritualist means."
Andrew Neher. (2011). Paranormal and Transcendental Experience: A Psychological Examination. Dover Publications. p. 214. ISBN978-0486261676 "William Crookes, the noted English physicist, had endorsed Catherine Fox as genuine... Crookes also endorsed several other mediums who were later exposed, including Anna Eva Fay (who was exposed more than once and who eventually explained how she duped Crookes), Florence Cook (who was the subject of more than one expose), and D. D. Home."
Leonard Zusne; Warren H. Jones. (2014). Anomalistic Psychology: A Study of Magical Thinking. Psychology Press. p. 216. ISBN978-0-805-80508-6 "The fact is that William Crookes, although very good at physics experiments, was rather weak on drawing inferences and on theorizing. Besides, he was gullible. He endorsed several mediums in spite of their demonstrated trickery. Having witnessed a single seance with Kate Fox, he became convinced that the Fox sisters' rappings were genuine."
Sherrie Lynne Lyons. (2010). Species, Serpents, Spirits, and Skulls: Science at the Margins in the Victorian Age. State University of New York Press. p. 101. ISBN978-1438427980