Thomson found that if the rays were magnetically bent and they could not enter the slit. This cylinder had two slits in it, leading to electrometers, which could measure small electric charges. To observe this he built a cathode ray tube with a metal cylinder on the end. ThomsonвЂ™s first experiment was to investigate whether or not the negative charge could be separated from the cathode rays by magnetism. He experimented with currents of electricity inside empty glass tubes. Overall: 30.5 cm x 8.Thomson started the Cathode Ray experiment in the 1894 (19th century) at the Cavendish Laboratory at Cambridge University. Glass metal wire (overall material) Measurements United Kingdom: England, Cambridge Physical Description LocationД®lectron tube, cathode ray (replica) date made By this means Thomson measured the ratio of the charge to the mass of the 'rays,вЂќ and established that they were particles, much lighter, and presumably much smaller, than atoms. The one with the greatest import, both for his research and for experimental techniques in the emergent field of atomic physics, effected the deflection of the cathode rays by electric and magnetic fields simultaneously.

Thomson devised many discharge tubes in his study of cathode rays. Thomson, Director of the Cavendish Laboratory, Cambridge University, produced convincing evidence that cathode rays were universal sub-atomic constituents of matter, of identical mass and electric charge. (See object ID EM.N-08517, Discovery of electron display apparatus with cathode ray discharge tube.)Д«etween 18 J. Philip Lenard, working in Germany, greatly intensified the physicists' interest in these 'cathode rays' by bringing them out of the discharge tube through a hole sealed with metal foil. In the early 1890s attention focused upon the rays which, at the highest evacuations, stream out from the negative pole (cathode) of the discharge tube and produce a fluorescent glow of its glass walls. (See object ID EM.N-08253, Geissler tube demonstration apparatus.) The development of theory and experimental technique raised expectations of insight from this quarter into the structure of the atom and the connection between matter and electricity. In the second half of the nineteenth century the phenomena accompanying the discharge of electricity through highly rarified gases received increasing attention from physicists. Thomson - the Centenary of His Discovery of the Electron and his invention of Mass Spectrometry, Rapid Communications in Mass Spectrometry, Vol.11, 2-16 (1997). Thomson, the Cavendish Laboratory, and Thompson's cathode ray tube and positive ray apparatus, see J.J. Used to determine the ratio of charge to mass (q/m) of the electron. External magnetic field can be applied to balance electric deflection. Metal plates can have electric field applied across them. Rays from cathode in cylinder pass through 2 metal slots and between 2 metal plates onto glass ball. Four shorter glass tubes with internal wires extend perpendicularly from the cylinderical body (see 1st object on left in accompanying image). This object consists of a glass cylindrical body with a larger diameter glass ball at one end.

Object ID EM.N-08013-A overall length 30.5 cm, glass ball diam. Thomson's cathode ray tube #2, replica of Cavendish Lab apparatus.

Jj thomson cathode ray tube