Description

An extremely fine Crookes Spinthariscope in original case c.1903.

Doubly signed “Spinthariscope, W. Crookes, 1903” and “Thos. Armstrong & Bro., Manchester, 657”, it retains all of it’s original golden lacquer, adjustable focal length by threaded eyepiece with lens, gold pointer with radium sample at tip (adjustable by knurled nut) sitting atop a zinc sulphide screen with blackened end cap. Original black card case measures 6 x 3 cm. in diameter.

Crookes came upon this phenomenon quite by accident and marketed it extensively for 1 GBP in 1903. Most were made by Beck and a few others in London. This is the first I have encountered by Armstrong, although the serial number would indicate a large number were made by his Firm. 

The idea was simple. An alpha particle source on the end of an inert pointer in proximity (variable) to a zinc sulphide screen would show flashes of light in a darkened room and the focal length could be adjusted for eyesight, with magnification via a bullseye lens. Radioactivity, being the latest discovery, soon became a fad among the gentry and sold like hotcakes.