The Crookes tube is a sealed glass tube that exhibits fluorescence in it after voltage is passed through the electrodes inside. It was invented in 1875 by Sir William Crookes.

around 1869-1875

Sir William Crookes was a British chemist who contributed to the knowledge of chemistry. One thing he did was discover an element that had a bright green emission line in its spectrum. He named the previously unknown element thallium.

The Crookes' Tube

Plasma was discovered by using a Crookes tube, wherein air is ionized in an electrical discharge tube, through the application of a high voltage. It was discovered by Sir William Crookes in 1879.