Method Making Visible Paths Ionising by Wilson (2 results)

"The Most Original Apparatus in the Whole History of Physics" Wilson, Charles Thomson Rees (1869-1959). (1) On a method of making visible the paths of ionising particles through a gas. In: Proc. Roy. Soc., series A, 85 (1911): 285-88. Plate. (2) On an expansion apparatus for making visible the tracks of ionising particles in gases and some results obtained by its use. In: ibid. 87 (1912): 277-292. 4 plates on 2 leaves. Together two whole numbers, 8vo. London: Harrison & Sons, 1911-12. 255 x 179 mm. Orig. printed wrappers, very slightly worn, pencil notations on back wrappers. Fine copies, very difficult to find in this condition. First Editions. Wilson received a share of the 1927 Nobel Prize for physics for his invention of the cloud chamber, which makes visible the tracks of ionizing particles. Wilson's device, which Rutherford called "the most original apparatus in the whole history of physics" (quoted in Magill, p. 344) became standard equipment in physics laboratories, and made possible numerous important discoveries in the fields of particle and nuclear physics. "The phenomena discovered empirically by Wilson may, briefly, be explained as follows. When air saturated with water vapor is suddenly cooled by an adiabatic expansion, it becomes supersaturated. In this condition, condensation into droplets will occur, provided there are nuclei present. Dust particles allow drops to form immediately, so Wilson carefully eliminated all gross matter from his apparatus. Negative ions act as nuclei at an expansion ratio of 1.25 (fourfold supersaturation) and positive ions become nuclei at 1.31 (sixfold supersaturation)" (DSB). Wilson constructed his first cloud chamber in 1895, and in 1910 designed an improved model with better illumination which allowed results to be photographed. In March 1911 Wilson was able to observe the track of an alpha ray by condensing water drops onto the ions produced by its passage, describing his results in "On a method of making visible the paths of ionising particles through a gas" (no. 1 above). No. 2, Wilson's classic "On an expansion apparatus for making visible the tracks of ionising particles in gases and some results obtained by its use," published a little over a year later, contains "some of the best photographs of alpha-particle, beta-particle and X-ray tracks" (Magill, p. 343). Weber, Pioneers of Science, pp. 85-87. Magill, The Nobel Prize Winners: Physics, pp. 339-47. .

London, Harrison and Sons, 1911. Small 4to. Contemp. full cloth. Spine gilt and with gilt lettering. A stamp to verso of titlepage and a few other leaves. In: "Proceedings of the Royal Society of London. Series A.", Vol. LXXXV. XXIII,605,XXIV pp. and 11 plates. (Entire volume offered). Wilson's paper: pp. 285-288 a. 1 plate. Clean and fine. First appearance of the paper which describes the final version of his invention, the famous Cloud-Chamber, - the first Cloud Chamber was invented by him in 1896 - for making visible and photographing the paths of charged particles, an invention for which Wilson received a share of the Nobel Prize in 1827. By using the Cloud Chamber he was here (1911) able to observe the track of an alpha ray by condensing water drops onto the ions produced by its passage.The Cloud Chamber, which Rutherford called "the most original apparatus in the whole history of physics", became standard equipment in physics laboratories, and made possible numerous important discoveries in the fields of particle and nuclear physicsAfter 1896 "Wilson continued to experiment with ultraviolet radiation and other techniques for producing condensation effects, but soon concentrated on atmospheric electricity, not returning to the cloud chamber until December 1910. He designed an improved chamber with new methods of illumination and the possibility of photographing the results. At this time Wilson realized that it might be possible to reveal the track of an a ray by condensing water drops onto the ions produced by its passage. During March 1911 he saw this effect produced in his apparatus. Thus, the elucidation of phenomena seen in the Scottish hills led to the possibility of studying the processes of radioactivity, and the Wilson cloud chamber became an important piece of laboratory equipment. But it was in the study of cosmic rays that it achieved its full power, particularly in the refined form developed by Patrick Blackett, in which it was possible to study particles of very high energy and the production of electron-positron pairs with the chamber situated in a strong magnetic field." (DSB).