cathode ray tube, Crookes style
Date: 1920-1940
Inventory Number: 1997-1-1305
Classification: Discharge Tube
Subject:
Maker: German
Cultural Region:
Dimensions:
20.4 × 22.3 × 9.7 cm (8 1/16 × 8 3/4 × 3 13/16 in.)
blue board box: 23.8 × 46.4 × 29.2 cm (9 3/8 × 18 1/4 × 11 1/2 in.)
Description:
This cathode ray tube consists of an exhausted cylindrical glass tube with the negative electrode at one end and the positive electrode on one side. A target in the form of a Maltese cross hinged at the bottom is located so as to cast a shadow on the end of the tube opposite the negative electrode. Rays may be deflected by an electromagnet. The whole glass structure is set into a turned wooden base.
In Collection(s)
Signedunsigned
FunctionThis Crookes's tube is for demonstrating that the energy of the electron stream of the cathode ray is converted into visible radiations by fluorescence of the glass tube. According to the Cenco trade catalogue, "After operation with the cross in the vertical position, 'fluorescence fatigue' of the glass is exhibited by shaking the cross into the [horizontal] position out of the electron stream. The position occupied by the shadow of the cross then glows more brightly than the surrounding glass."
A short visual display is found on YouTube here.
A short visual display is found on YouTube here.