Geissler Tube

Geissler tubes were arguably the first discharge tubes often using just air at low pressure. They were really only Victorian objet d’art at the time. Some became very intricate in their designs. This particular one has a fluorescing liquid in the surrounding glass jacket which reacts to the UV content of the discharge gas. The gas here may be argon or just air and the nitrogen content will be producing some UV light.
The Geissler tube is being powered from a very modern supply but also one of the last electronic inverters designed to drive a CFL for back lighting laptop computer LCD displays.