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Two volumes. 222 x 153 mm. 8vo. Pages 735-740; 83-90. [Both volumes: viii,1208; viii, 876 pp.] Quarter brown cloth, marbled boards, gilt spines. Blind-stamps of the Carnegie Institution, Washington. Fine. FIRST EDITIONS. "Soon after the discovery (1896) of radioactivity Elster and Geitel began to study Becquerel rays, in order to determine the origin of the energy of these rays. [William] Crookes (1832-1919) had proposed the hypothesis that the air molecules with the greatest velocity stimulated the rays; energy was therefore extracted from the surrounding air. Elster and Geitel placed uranium in a glass vessel that was then evacuated: even at the highest vacuum the radiation remained constant. They also placed uranium and a photographic plate in a container: the blackening of the plate was independent of the pressure. Therefore the radiation could not be stimulated by the air. Mme. Cure suggested another hypothesis: the radioactive emission was a fluorescence of the uranium, which was excited by a very penetrating radiation that fills all of space. She therefore named the new phenomenon la radioactivite, i.e., 'activated by radiation.' Elster and Geitel showed, however, that the intensity of the uranium radiation above the earth is the same as it is in a mine 852 meters below the surface. They also investigated whether uranium emitted stronger Becquerel radiation when under the influence of cathode rays. For this purpose they developed a new Lenard cathode-ray tube, which let pass into the atmosphere an intense electron beam with a cross section of several square centimeters. (They closed off the discharge tube with a copper net covered with a very thin aluminum foil; the cathode rays escaped through the net's interstices.) The result was negative. They also demonstrated that Becquerel radiation is independent of the temperature of the uranium and of the compound in which it occurs. They concluded from these and other experiments that the radioactive emission is not the consequence of an external influence, but can only be a spontaneous release of energy by the atom." DSB, IV, p. 355. "Elster and Geitel, as inseparable in their life as in their work, were called 'the Castor and Pollux of physics.' They set up their physics laboratory in their residence, which also contained an astronomical telescope, terraria with tropical animals, and all kinds of natural history collections. They took vacation trips together to investigate the electricity in mountain and sea air and to measure the radioactivity of rocks, springs, and spas." DSB, IV, p. 356. In 1905, 1907, 1908, 1910, and 1911 they were nominated for the Nobel Prize. For a detailed discussion these two papers, see: Pais, Inward bound, pp. 109-111. First Edition.
Title: Versuche an Becquerelstrahlen. [with]: Weitere Versuche an Becquerelstrahlen.
Publisher: In: Annalen der Physik und Chemie, Neue Folge, Band 66 + 69. Leipzig:, Johann Ambrosius Barth, 1898, 1899.: 1898
lbs: 3.00 lbs
Seller ID: S3134