A Crookes tube is an early experimental electrical discharge tube, invented by English physicist William Crookes and others around 1869-1875, in which cathode rays, streams of electrons, were discovered. Wilhelm Röntgen discovered X-rays using the Crookes tube in 1895. The term is also used for the first generation, cold cathode X-ray tubes, which evolved from the experimental Crookes tubes and were used until about 1920.(

Physical description

Glass vacuum tube with a metal maltese cross inside. The tube is on a timber stand.