112475-01  Rutherford, E(rnest).
Radioactivity produced in Substances by the Action of Thorium Compounds. (22 x 14,5 cm). SS. (161)-192. Mit 12 Abbildungen. Halbleinwandband um 1920. (Sonderdruck aus: Philosophical Magazine).
(London, Taylor & Francis), 1900.
Erste Ausgabe einer der ersten Schritte hin zu einer mathematischen Beschreibung der Radioaktivität, hier im seltenen Sonderdruck. - "In Montreal his first inclination was to examine thorium substances, since the activity of this element had been noticed only half a year earlier. When a colleague obtained erratic ionization measurements. Rutherford succeeded in tracing the irregularity to a gaseous radioactive product escaping from the thorium; and because he was uncertain of the nature of this product, in 1900 he gave it the deliberately vague name 'emanation.' Within a short time the emanations from radium and actinium also were found, by Ernst Dorn and F. Giesel, respectively. The number of known radioelements was increasing. Rutherford added several more to the list, the next being thorium active deposit, which in time was resolved into thorium A, B, C, and so on. The active deposit, or excited activity, which was laid down on surfaces touched by the decaying emanation, was found by Rutherford because of the apparent breakdown of good insulators and was described in 'Philosophical Magazine' just one month after his announcement of the emanation. A curious feature he immediately noticed was that, unlike uranium, thorium, and radium, such materials as thorium emanation, radium emanation, their active deposits, and polonium lost their activities over periods of time. Moreover, the rate of this decrease was unique for each radioelement and thus an ideal identifying label. This meant that an exponential curve could be plotted for the half-life of each radioelement with a discernible decay period, and theory could thereby be compared with experiment" (DSB). - Erstes und letztes Blatt jeweils gebräunt, sonst gut erhalten. - DSB 12, 25

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