This shot shows a close-up view of the burner inside a 1950s Philips HPW lamp. The particularity of it is the presence of electrodes made of thorium pellets enclosed in a tungsten coil. Such design was used in medium-pressure mercury lamps of the glass burner type, mostly by G.E.C., B.T.H. and Crompton in the U.K. It is well possible that Philips made this lamp in its Hamilton, Scotland, factory and outsourced its burner from British Thomson Houston.
