Beginning of Essay
Science lecturers who traveled from town to town in the middle nineteenth century delighted audiences by showing them the ancestor of the neon sign. They took a glass tube with wires embedded in opposite ends . . . put a high voltage across . . . pumped out most ....

Middle of Essay
.... including J.J. Thomson, thought that all material particles themselves might be some kind of structure built out of ether, so these views were not so far apart. Experiments were needed to resolve the uncertainties. When physicists moved a magnet near the glass, they found they could push the rays about. Nevertheless, when the German physicist Heinrich Hertz passed the rays through an electric field created by metal plates inside a cathode ray tube, the rays were not deflected in the way that would be expected of electrically charged particles. Hertz and his student Philipp Lenard also placed a thin metal foil in the path of the rays and saw that ....