AP Physics Period 2 In the spring of 1897 J.J. Thomson demonstrated that the beam of glowing matter in a cathode-ray tube was not made of light waves, as "the almost unanimous opinion of German physicists" held. Rather, cathode rays were negatively charged particles boiling off the negative cathode and attracted to the positive anode. These particles could be deflected by an electric field and bent into curved paths by a magnetic field. They were much lighter than hydrogen atoms and were identical "what ever the gas through which the discha ....