He knew that electrical charges repelled on another, which allowed him to see whether the charge was a positive or negative. This vacuum had two electrical pates halfway down the tube, one positively charged and one negatively charged. Thomson made a cathode ray with an almost perfect vacuum. His previous experiments did not prove this but he wanted to keep trying because he believed his previous experiment had been flawed because of the traced amounts of gas and a bad vacuum. Thomson’s second experiment was to prove that the rays carried a negative charge. Since the electrometers recorded no activity and so the charge had been bent away by the magnet. He found his conclusion by applying a magnetic field across the tube.

Thomson concluded that the negative charge was inseparable from the rays. Therefore, the electrometer registered little charge. 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.

Thomson’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. Thomson started the Cathode Ray experiment in the 1894 (19th century) at the Cavendish Laboratory at Cambridge University.

J.j.thomson cathode ray