J. J. Thomson

Sir Joseph John Thomson, OM, FRS (18 December 1856 – 30 August 1940), often known as J. J. Thomson, was a British scientist. Thomson is credited with the discovery of the electron and isotopes, and the invention of the mass spectrometer.

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• I have described at some length the application of Positive Rays to chemical analysis; one of the main reasons for writing this book was the hope that it might induce others, and especially chemists, to try this method of analysis. I feel sure that there are many problems in chemistry, which could be solved with far greater ease by this than any other method. The method is surprisingly sensitive — more so than even that of spectrum analysis, requires an infinitesimal amount of material, and does not require this to be specially purified; the technique is not difficult if appliances for producing high vacua are available.
  • Rays of Positive Electricity (1913)