G3YNH.info Spectrum Tubes

Capillary spectrum tube.
Crookes tube with capillary.
Capillary spectrum tube, ca 1930, labelled C2H2 (acetylene).
This item is in the collection of the Porthcurno Telegraph Museum. (where it is catalogued, somewhat generically, as a "Crookes Tube").
     The narrow middle section eliminates the need for a slit-collimator when examining the light output with a simple prism or grating spectroscope (it also ensures high brightness when a slit is used). This type of tube, with a wide choice of gas fills, is used for teaching laboratory demonstrations and is still readily available (cost ca. £20 - £60 UK inc. VAT from educational suppliers).  

See, for example:
www.eiscosci.com/ Eisco Scientific
www.eiscolabs.com/ Eisco scientific online catalogue .
www.betterequipped.co.uk/ [type ' spectrum tube ' into the search box].

spectrum tube
A modern Spectrum Tube



Discharge Tubes

© D. W. Knight, 2013