Abel Niépce de Saint-Victor

Claude Félix Abel Niépce de Saint-Victor (1805-1870)

Claude Félix Abel Niépce de Saint-Victor (26 July 1805, Saint-Cyr, Saône-et-Loire – 7 April 1870, Paris) was a French photographic inventor. An army lieutenant and cousin of Nicéphore Niépce, he first experimented in 1847 with negatives made with albumen on glass, a method subsequently used by the Langenheim brothers for their lantern slides. At his laboratory near Paris, Niépce de Saint-Victor worked on the fixation of natural photographic colour as well as the perfection of his cousin's heliographic process for photomechanical printing. His method of photomechanical printing, called heliogravure, was published in 1856 in Traité pratique de gravure héliographique.[1] In the 1850s he also published frequently in La Lumière.

Near-discovery of radioactivity

In 1804 the German chemist Adolph Ferdinand Gehlen (1775-1815) had noticed that when a solution of uranium chloride in ether was exposed to sunlight, it quickly changed color (from bright yellow to green) and precipitated.[2] In the 1850s, Niépce de Saint-Victor was trying to develop color photography, using light-sensitive metal salts. Beginning in 1857, long before Henri Becquerel's famous serendipitous discovery of radioactivity in 1896, Niépce de Saint-Victor observed that, even in complete darkness, certain salts could expose photographic emulsions.[3][4] He soon realized that uranium salts were responsible for this anomalous phenomenon.[5] Niépce recognized that the “light” that was exposing his photographic plates was neither conventional phosphorescence nor fluorescence: the salts could expose photographic plates long after the salts had last been exposed to sunlight. Niépce's superior, Michel Eugène Chevreul, recognized the phenomenon as a fundamental discovery ("une découverte capitale"), pointing out that uranium salts retained their power to expose photographic plates even after six months in the dark ("encore actif six mois après son insolation").[6] By 1861, Niépce stated frankly that uranium salts emitted some sort of radiation that was invisible to the human eye:

Original : " … cette activité persistante … ne peut mème pas être de la phosphorescence, car elle ne durerait pas si longtemps, d'après les expériences de M. Edmond Becquerel; il est donc plus probable que c'est un rayonnement invisible à nos yeux, comme le croit M. Léon Foucault, … ."[7]
Translation : " … this persistent activity … cannot be due to phosphorescence, for it [i.e., phosphorescence] would not last so long, according to the experiments of Mr. Edmond Becquerel; it is thus more likely that it is a radiation that is invisible to our eyes, as Mr. Léon Foucault believes, … ."

Note especially that Niépce mentions "Edmond Becquerel", the father of Henri Becquerel, who would later be credited with the discovery of radioactivity. Indeed, in 1868, Edmond Becquerel published a book, La lumière: ses causes et ses effets (Light: its causes and its effects), in which he mentioned Niépce's findings; specifically, that objects that were coated with uranium nitrate could expose photographic plates in the dark.[8][9]

References

  1. ↑ Niépce de Saint-Victor, Traité Practique de Gravure Héliographique sur Acier et sur Verre (Practical treatise on heliographic engraving on steel and on glass) (Paris, France: Victor Masson, 1856).
  2. ↑ A. F. Gehlen (1804) "Ueber die Farbenveränderungen der in Aether aufgelösten salzsauren Metallsalze durch das Sonnenlicht" (On the color changes, via sunlight, of metal chlorides dissolved in ether), Neues allgemeines Journal der Chemie (New General Journal of Chemistry), 3 (5) : 566-574. From page 569: Eine Auflösung von reinem salzsauren Uran wurde so weit abgedampft, daß sie in der Kälte ein trockenes Salz gab. Dieses wurde in einem Glase in absolutem Aether aufgelöst. Die schön citrongelbe Auflösung in einem ganz damit gefüllten Glase den Sonnenstrahlen ausgesetzt, wurde schon in einigen Sekunden verändert: sie wurde grünlich trübe und es schied sich ein schmutzig grüner Niederschlag aus, … (A solution of pure uranium chloride was so thoroughly evaporated that it gave a dry salt in the cold [air of the lab]. This was dissolved in a glass of absolute [i.e., pure] ether. The beautiful lemon yellow solution, which quite filled the glass and was exposed to the sun's rays, was changed in just some seconds: it became a cloudy green and there precipitated a dirty green precipitate, … )
  3. ↑ Rothman, Tony, Everything's Relative: And Other Fables from Science and Technology (New York, New York: Wiley, 2003) Chapter 5 "Invisible light: The discovery of radioactivity," pages 46-52. ISBN 0-471-20257-6 See also: Amazon.com .
  4. ↑ Niépce de Saint-Victor (1857) "Mémoire sur une nouvelle action de la lumière" (On a new action of light), Comptes rendus … , vol. 45, pages 811-815.
  5. ↑ Niépce de Saint-Victor (1858) "Deuxième mémoire sur une nouvelle action de la lumière" (Second memoir on a new action of light), Comptes rendus … , vol. 46, pages 448-452.
  6. ↑ M.E. Chevreul (1858) "Influence de la lumière dans les actions moléculaires" (Influence of light in molecular actions), Comptes rendus … , vol. 47, pages 1006-1011; see especially page 1010.
  7. ↑ Niépce de Saint-Victor (1861) "Cinquième mémoire sur une nouvelle action de la lumière" (Fifth memoir on a new action of light), Comptes rendus … , vol. 53, pages 33-35.
  8. ↑ Edmond Becquerel, La lumière: ses causes et ses effets, vol. 2 (Paris, France: F. Didot, 1868), page 50.
  9. ↑ On the controversy about whether Henri Becquerel knew about Niépce de Saint-Victor's earlier discovery of radioactivity in uranium, see:
    • Michèle Meyer and Erick Gonthier (June 1997). "Y a-t-il encore polémique autour de la découverte des phénomènes dits radioactifs?" [Is there still controversy about the discovery of radioactive phenomena?]. Science Tribune.
    • Michel Genet (1995) "The discovery of uranic rays: A short step for Henri Becquerel but a giant step for science," Radiochimica Acta 70 / 71 : 3-12. This was part of a special issue of Radiochimica Acta which was reprinted in book form as: J. P. Adloff, ed., One Hundred Years After the Discovery of Radioactivity (Munich, Germany: R. Oldenbourg Verlag, 1996); see pages 3-12. Available (in part) on-line at: Google Books.
    • J. Fournier and P. Fournier (1990) "A. Niépce de Saint-Victor (1805-1870), M. E. Chevreul (1786-1889) et la découverte de la radioactivité," New Journal of Chemistry, 14 (11) : 785-790.
    • At about the same time that Henri Becquerel made his discovery, the English physicist Silvanus P. Thompson (1851-1916) independently observed that uranium salts emit a radiation that can penetrate opaque materials. See page 104 of: Thompson, Silvanus P. (1896) "On hyperphosphorescence," Philosophical Magazine, 42 : 103-107. (Thompson also mentions Niépce de Saint-Victor's findings.)

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