If we consider that Sir William Crookes (1832-1919) had communicated the results of his discharge tube experiments with extremely rarefied gases in 1879, we can see that this tube, inventoried in 1881, is of great historical importance. The central part of the tube, which is obviously all made of glass, is cylindrical (diameter 2.6 cm, length 8 cm) while one end is an ovoid and the other a sphere.
Of the two linear electrodes one, 3 cm long and oriented in the direction of the axis of the tube, is soldered to the ovoid end and the other is soldered to the spherical part, perpendicularly to the axis of the tube, with the free end falling slightly beyond the axis.
The spherical end communicates with the rest through a diaphragm to which a tube, coaxial with the main one, is attached. The former is made up of four parts with glass of different qualities; one of these is yellowish and has the shape of a vase with a narrow neck and bottom. It is followed by a blue hemispherical one, then a conical one that is white and opaque and finally a small transparent tube. ...continues