Early Bulbar Tube

Ref. B3

This tube is ten inches (25 cm) long with a 3.75” (9.5 cm) bulb, dating probably to the early years of the 20^th century.

It has a flat aluminum disc anode, concave aluminum cathode, showing definite discoloration, a 45-degrees anti-cathode, a shiny platinum target, held in place by 4 small claws, and showing some erosion at the focal spot and platinum wire electrode terminals looped around the neck of the copper hemispheric external connections of the tube.

There is no regeneration device and no maker’s name. The serial number “4657” is etched on the glass arm.