Radioactive source for Crookes spinthariscope

Background on Crookes spinthariscope, Object ID 1994.0125.17.1
A spinthariscope is a device for observing individual nuclear disintegrations caused by the interaction of ionizing radiation with a phosphor or scintillator. Typically, an eyepiece and a radiation source are located at opposite ends of the cylindrical device.
Two types of spinthariscope are shown in the accompanying multi-object image; a Crookes spinthariscope appears on the right. (Photograph provided by donor, Prof. Herbert Clark, Rensselaer Polytechnic Institute.)
For general background on the spinthariscope go to:
For background on the Crookes spinthariscope go to:
Description of the separate source for the Crookes spinthariscope, object ID no. 1994.0125.17.2
This separate radioactive source, presumably radium, for Crookes spinthariscope object ID 1994.0125.17.1, is enclosed in a 3 7/8” x 1 ½” x ¼” case of unknown material, with a cardboard lid held by a cloth hinge in which a rectangular window roughly 2” wide by 1” deep. Behind the window is a circular depression about 3/8” in diameter, in the center of which embedded in an unknown white matrix, the presumed 1 mm diameter source lies. Visible through the window, above the source well is the inscription “The Spinthariscope”, and below the source well is the inscription “W. Crookes 1903”. The source .17.2 in the case appears in the accompanying multi-object image, second object from the right.
The sides of the case are further enclosed by stacks of glass microscope slides 3/16’ thick, held by twisted wires and foam pads over top and bottom. The glass slides were placed on both sides of the case by Clark; they have been left undisturbed as a precautionary measure. The object .17.2 in this arrangment appears in the second accompanying image.
Currently not on view
Object Name
radioactive source for Crookes spinthariscope
date made
early 20th century
Crookes, William
Physical Description
metal (overall material)
cloth (overall material)
radioactive source (overall material)
glass (overall material)
overall: .8 cm x 9.8 cm x 3.8 cm; 5/16 in x 3 7/8 in x 1 1/2 in
ID Number
accession number
catalog number
Science & Scientific Instruments
See more items in
Medicine and Science: Modern Physics
Science & Mathematics
Measuring & Mapping
Modern Physics
Data Source
National Museum of American History, Kenneth E. Behring Center


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