Mini-Research ELECTRON- In 1897, Sir J. J. Thomas, an English physicist, measured the deflection of cathode-ray particles in magnetic and electrical fields. As a result he found the ratio of the charge, e, to the mass, m, of the cathode-ray particles. He found e/m identical to those particles irrespective of the metal the electrodes were made of or the kind of gas in the tube. In 1909, RA Millikan, an American scientist, measured that charge. All electrons are found to be identical no matter their source or the method of liberating them from matter. From the values of e/m, and e, the mass of an electron was calculated to be .00055 amu. PROT