This exhibit is an early (possible 1910-20) cold cathode X-Ray tube. There are no markings on the glass to give information.
Both cathode and anode are in the form of flat discs. Any X-Rays produced would be scattered and not held in a tight cone, contrast this to the more developed structure here.
A closer view of the electrodes. Just visible is the glass tube housing the anode lead. On the left is the copper oxide of the glass to metal seal.
In this X-Ray image of the tube the glass tube covering the anode lead is very clear. The evacuation tube is a long swan neck.
The balloon envelope is 80 mm in diameter, and including the base pins is 305 mm tall.
Updated March 25, 2019. shape:balloon construction:pinch type:x-ray.tube age:pre.1920 base: pin: