The cathode ray tube is a glass container like the one seen in the figure. It has two electrodes: the cathode and the anode. When there are electric and magnetic fields around the middle of the tube, the electric nature of the rays can be studied. In 1896, Thomson deduced that the particles were electrons that escaped the cathode and travelled towards the anode.
Use the mouse pointer to hover over the image and you will be able to observe the phenomenon. The Crookes tube was a predecessor of the cathode ray tube.

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