cathode ray tube, Crookes style
Date: circa 1940
Inventory Number: 1997-1-1797
Classification: Cathode Ray Tube
Subject:
Maker: German
Supplier: Central Scientific Company (1889 - 2000)
Cultural Region:
Place of Origin:
Dimensions:
26 x 30 x 12 cm (10 1/4 x 11 13/16 x 4 3/4 in.)
Bibliography:
General Catalog of Laboratory Apparatus and Scientific Instruments
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
Inscribedon glass: Made in Germany
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.
Curatorial RemarksThis tube is almost identical to the one advertised in the Cenco trade catalogue of 1941. It is why we attributed it to this maker, who in this case was the supplier since the tube was manufactured in Germany.
On this type of Crookes tubes in general, see the following website.
On this type of Crookes tubes in general, see the following website.
Primary SourcesCENCO, Scientific Instruments, Laboratory Apparatus and Supplies for Physics, Chemistry, Biological Sciences and Industrial Testing (Chicago: CENCO, 1941), 962, no. 71560.