Signedstamped in white on bulb: COOLIDGE / (GE logo) / - TUBE - / REG. U.S. PAT. OFF. / 3R21913
Inscribedstamped in white on tube: MF'D NOV. 3, 04 SEPT. 6, 11 FEB. 27, '12 / FEB. 16, '12 DEC. 30, '13 JUNE 29, '14 MAY 18, '15 / NOV. 30, '15 OCT. 31, '16 JAN. 2, '17 JULY 16, '19 / DEC. 29, '19 / PATENTS PENDING / THIS TUBE IS NOT LICESNSED TO BE / RE-EXAUSTED OR REPAIRED NOR / THE METAL THEREIN CONTAINED / LICENSED TO BE USED EXCEPT IN / THIS PARTICULAR TUBE. / GENERAL ELECTRIC X-RAY CORP. / CHICAGO, ILL., U.S.A.
etched on copper inside tube: 24257
FunctionThis Coolidge tube produces electrons by the heating of a cathode filament. These electrons are accelerated by a high voltage and hit the angled anode to produce the x-rays. Due to the large amounts of generated heat, this unit has radiator fins as a cooling mechanism, which allowed for a relatively small bulb size. It could also work without a rectifier as the anode was kept cold enough not to emit electrons for an inverse current. This one is a diagnostic tube.
ProvenanceFrom the Harvard Medical School. Originally Dr. Burton W. Trask's.