British Admiralty lightbulb
Robertson light bulb - probably a wire filament, BC 100v 32cp made 1920's - 30's. It bears an acid etched Admiralty cypher of an foul anchor in an oval surmounted by crown, on one side and GEC and Robertson marks on top. Unmarked corrugated card and paper wrapper.
Robertson was a GEC company set up in the UK when Edison patents ran out in 1893, with C J Robertson who had a light bulb factory in Europe supplying GEC.
Sold 2003
