ONE HUNDRED YEARS OF ELECTRONS. On April 30, 1897, at a meeting of the Royal Institution in London, physicist Joseph John (J.J.) Thomson declared that cathode rays lighting up a fluorescent screen were made of negatively charged particles. Thomson boldly proclaimed that these particles--which we now know as electrons--could be found in all atoms. The term "electron" as it applied to electricity actually came about in 1891 to describe the unit of electric charge in a chemical reaction. The electron was the first known subatomic corpsucle and its discovery marks the advent of particle physics. Michael Riordan (editor of SLAC Beamline, whose Spring 1997 issue is devoted to the electron centennial) refers to the electron as a truly "industrial strength" particle, since it is the workhorse of electronics, including television, telephones, and personal computers. (Many of these devices organize electrons inside transistors which were themselves developed exactly half a century ago.) Labor saving devices aside, electrons are of course the outer constitutents of all atoms and the principal currency of exchange in all chemical reactions. (See also the AIP History Center's web exhibit)