‎"WILSON, C.T.R. - THE MOST ORIGINAL AND WONDERFUL INSTRUMENT IN SCIENTIFIC HISTORY - WILSON'S CLOUD CHAMBER.‎
‎Über die Expansionsapparat zur Sichtsbarmachung der Bahnen ionisierender Teilchen in Gasen, und über einige mittels dieses Apparats gewonnene Ergebnisse. Mit 23 Figuren im Text und auf 5 Tafeln. (Eingegangen 6. Oktober 1912). (On an Expansion Apparatu...‎

‎Leipzig, S. Hirzel, 1913. 8vo. Orig. printed wrappers, no backstrip. Wrappers loose. In ""Jahrbuch der Radioaktivität und Elektronik"", 10. bd., Heft 1. Pp. 1-138 (entire issue offered). Wilson's paper: pp. 34-54, textillustrations, showing apparatus and 5 photographic plates, showing ionizing by Alpha-, Beta- and Röntgen- radiation).‎

Reference : 45816

‎Together with the English version - published 1912 in the Proceedings of the Royal Society - this is Wilson's main paper relating ""that the track of an ionizing particle might be made visible and photographed by condensing water of the ions which is liberated"". The first trails were obtained in 1911 where he submitted a short note of this to the Proceedings. In the offered paper he published the first tracks made by the ionizing particles of alpha, beta and Röntgen-rays. This, Wilson Cloud-Chamber, became an extremely valuable instrument of fundamental research, the discovery of the positron in 1932 and the kaon in 1963 were made by using cloud chambers as detectors.""But the whole course of the particle appears infinitely more clearly by the method invented by C.T.R. Wilson in 1911 and named after him. The radiation is allowed to enter an expansion-chamber, containing a gas saturated with water vapour. A sudden expansion of the chamber cools the gas, and cloud-drops are then formed instantly around the ions produced along the tracks of the particles. By suitable illumination these tracks can be made to stand out clearly as if they had been described by luminous projectiles. The ""Altmeister"" of modern nuclear physics, Lord Rutherford, once called the Wilson chamber ""the most original and wonderful instrument in scientific history"".""Thomson Rees Wilson (1869-1959), a Scottish physicist, is credited with inventing the cloud chamber. Inspired by sightings of the Brocken spectre while working on the summit of Ben Nevis in 1894, he began to develop expansion chambers for studying cloud formation and optical phenomena in moist air. Very rapidly he discovered that ions could act as centers for water droplet formation in such chambers. He pursued the application of this discovery and perfected the first cloud chamber in 1911. In Wilson's original chamber the air inside the sealed device was saturated with water vapor, then a diaphragm is used to expand the air inside the chamber (adiabatic expansion). This cools the air and water vapor starts to condense. When an ionizing particle passes through the chamber, water vapor condenses on the resulting ions and the trail of the particle is visible in the vapor cloud. Wilson, along with Arthur Compton, received the Nobel Prize in Physics in 1927 for his work on the cloud chamber. (Wikipedia).‎