History-of-science papers found (arXiv, einar.hi.is, ghtc.usp.br, UC Press/JSTOR listing)

Visit: 2026-10-08. Downloads in research/files/: Kragh-2012-Eight-Physicists-arXiv1208.3114.pdf, Kragh-2012-A-Sense-of-Crisis.pdf, Martins-Becquerel-experimental-mistakes-Studia-2-3.pdf.

1. Helge Kragh, "Eight Physicists and Astronomers: Biographical Portraits", arXiv:1208.3114 (2012) [web]

https://arxiv.org/pdf/1208.3114 - found via Google Mary Jo Nye "Gustave LeBon's black light". Kragh's characterization (historian of physics; mainstream view): "In 1896 Le Bon announced that he had discovered what he called 'black light' ... The discovery claim attracted much attention among French scientists, many of whom supported it and Le Bon's general ideas of matter, radiation, and ether. Although black light turned out to be imagination rather than reality – most physicists failed to detect the rays – for a while they established Le Bon as an important figure in French scientific and intellectual life. In 1903 he was even nominated for the Nobel Prize in physics. Among his friends and admirers were ... Moissan ... Deslandres ... Picard and ... Poincaré." He calls the cosmology "a speculative and purely qualitative theory of cosmic evolution and devolution". Note for weighing: "most physicists failed to detect the rays" is Kragh's summary; he cites no specific failed replication here. The Poincaré Papers record one reproduction (Berget, 1897) and Le Bon's later re-sorting assigned parts of the 1896 effect to infra-red and phosphorescence, which are real phenomena. The reviewers should separate "black light" as the 1896 single new agent (Kragh's subject) from the 1899-1908 infra-red and invisible-phosphorescence results (claim 4).

2. Helge Kragh, "A Sense of Crisis: Physics in the fin-de-siècle Era" (2012 preprint) [web]

https://einar.hi.is/Heimsfraedi/Kragh_2012.pdf - found via Google "Le Bon" "rayons N" OR "N-rays" "black light" Blondlot Nye history. "Although black light turned out to be no more real than N-rays, for a while the discovery claim was taking seriously. In 1903 Le Bon was even nominated for a Nobel Prize in physics." Le Bon's ether is "the final nirvana to which all things return" (quoting Le Bon 1907: 315); his views "congruent" with Oliver Lodge's; a 1903 French newspaper: "Poincaré and Le Bon fearlessly undermine the old scientific dogmas" (via Nye 1974: 185). Bearing: claim 1 and 5 (context; the "revolt against positivism"); related work: Lodge.

3. Roberto de Andrade Martins, "Becquerel's experimental mistakes" (Studia, vol. 2-3; USP GHTC) [web]

https://www.ghtc.usp.br/livros%20RM%202022/Studia-2-3-web.pdf - found via Google "Le Bon" "lumière noire" 1896 "Comptes rendus". - "Gustave le Bon, whose work on 'black light' had been strongly criticized by Henri Becquerel, was the first to deny the polarization of uranium radiation, in May 1897." Martins quotes Le Bon (1897, p.691): "I suppose that the qualification 'pretended' applied to black light means simply that my experiments do not always succeed. They do indeed not invariably succeed mainly because of the difficulty in preparing plates that are sensible to those new radiations. But if the qualification 'pretended' should be applied to all experiments that do not always succeed, couldn't we apply it also to uranium rays?" - Le Bon 1899 (pp.108-109): "Metallic radiations, including uranium radiations, have never shown any trace of polarization, by any of several methods I have used, even after an exposure of three months." - Becquerel 1900 (p.54), after his own retraction: "The same negative conclusions were observed by Mr. Rutherford and Mr. Le Bon." Martins notes that in his 1903 book Becquerel gave "No credit ... to Rutherford, Schmidt, Le Bon and others." Bearing: claim 5. A modern historian documents one case where Le Bon was right against H. Becquerel (no polarization of uranium rays; Becquerel's polarization result was an error) and where credit to Le Bon was later dropped. It also records Le Bon's own admission that his black-light experiments did "not invariably succeed". A related Martins paper, "A pool of radiations: Becquerel and Poincaré's conjecture" (ResearchGate/Academia), and his "Did Niepce de Saint-Victor discover radioactivity?" (Le Bon charged Becquerel with plagiarism of Niepce) were seen in results, not read.

4. Mary Jo Nye, "Gustave LeBon's Black Light: A Study in Physics and Philosophy in France at the Turn of the Century", Historical Studies in the Physical Sciences 4 (1974), pp.163-195 [web: listing only]

https://online.ucpress.edu/hsns/article/doi/10.2307/27757330/47934 ; JSTOR. Paywalled; not read. This is the standard history of the black-light episode, and Nye's notes are the source of many Poincaré Papers summaries. Priority for the next run (or for the owner to obtain). Also listed: "Gustave Le Bon: A 'Scientific Irregular' and His Media" (ResearchGate 402964024), not read.