(n)English chemist and physicist; discovered thallium; invented the radiometer and studied cathode rays (1832-1919), Syn.Sir William Crookes, William Crookes
[ After Sir William Crookes, English chemist, who first described it. ] (Physics) The dark space within the negative-pole glow at the cathode of a vacuum tube, observed only when the pressure is low enough to give a striated discharge; -- called also Crookes layer. [ Webster 1913 Suppl. ]
(Phys.) A vacuum tube in which the exhaustion is carried to a very high degree, with the production of a distinct class of effects; -- so called from W. Crookes who introduced it. [ 1913 Webster ]