FIRST EDITIONS OF THOMSON'S PAPERS ON THE DISCOVERY OF THE ELECTRON.
The two papers demonstrated the discovery of the electron. In 1897, J. J. Thomson completed measurements of cathode rays and announced on April 30, 1897 that they are comprised of corpuscles with a charge to mass ratio (e/m) roughly one thousand times that of the hydrogen ion. Because he thought that the charge of the corpuscle might be the same as the hydrogen ion measured in electrolysis, he speculated that the mass of the negatively charged corpuscle could be as little as one thousandth of the hydrogen atom. This was printed in the famous paper "Cathode Rays." In the following two years, Thomson conducted additional experiments to determine (rather than just infer) the charge of the corpuscle and improve the precision of his measurements of e/m. He also performed these measurements on corpuscles generated through other mechanisms (e.g., ions created by X-rays) and found that the results were the same regardless of source. In 1899, in the second of these papers, Thomson concluded that the corpuscle was a subatomic particle with a mass 1/1000 of the mass of the hydrogen atom, thus confirming the discovery of the electron.
"On the Charge of Electricity carried by the Ions produced by Röntgen Rays" (The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science 46 pp. 528-545, 1898) and “On the Masses of the Ions in Gases at Low Pressures,” (The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science 48 pp. 547-567, 1899).
Two volumes. Quarto. Both volumes beautifully bound in leather and boards. Back of title pages strengthened. Otherwise fine.