This Osglim neon tube was used by Baird as the light source for early televisors. When connected correctly the neon glow spreads evenly across the face of the plate, that is the side opposite the horizontal wire. Reversed connections allow the glow to circle the horizontal wire.
This image found on the internet shows the neon lamp at the rear of the scanning disc.
The standard light bulb bayonet connections.
The lamp is designed to be modulated and must be operated with a series resistance if directly connected to a voltage source.
The two electrodes of this neon lamp are a polished flat plate and a horizontal wire. The plate has a mica sheet over the surface facing the horizontal electrode.
The plate is held by the strut from the left hand connection that passes to the base of the plate and the wire from the pinch extension to the top.
The horizontal wire passes within the loop of the plate lower connection.
The flat plate has turned-up edges for rigidity.
The working lamp showing an even light distribution over the plate.
The wide glass tube envelope is 52 mm in diameter, and including the base is 165 mm tall.