Farny’s first cathode glow experiment

Farny's First Cathode Glow Experiment

Farny's first experiment did not use any noble gas. First he turned on the high voltage PSU (presumably ~180V) then turned the pump on. As the pressure in the bottle dropped, the glow changed.

In his initial setup, a glass jar was used as the tube, with one hole for the air-evacuation tube, and another for the cathode wire, sealed with hot glue. The lid of the jar was used as the anode.

(Sketch: glass jar containing cathode and anode, connected via tube to a vacuum pump, powered by a PSU.)