Crookes tube for demonstrating cathode ray independence of positive pole, marked: "P1B2". Pear-shaped construction. Concave focusing cathode is mounted in tube with three rod-type anodes. Five inch glass stem forms base of tube. Purpose of the tube was to trace the path of an electron beam through a partial vacuum by observing luminosity patters as positive voltage was applied to each anode. Reference: Crookes, "On Radiant Matter," 1881, pages 11-14.
Full wave vacuum rectifier. A 4-pin plastic base with BT-shaped envelope. Stamped on base: "RCA Radiotron / Made in U.S.A. / R5 / Licensed / as stated / on carton"; on envelope: "5Z3". Paper label reads: "Guaranteed 90 days against / factory defects. / Heins & Bolet / 68 Cortlandt Street N.Y.C. / Date 10/11/40". Reference: https://www.radiomuseum.org/tubes/tube_5z3.html.
