Bulbar Focus Tube

with Carbon regeneration

This peculiarly shaped tube bears no maker’s name. The only information is a label “G.B.Paravia & C” fixed on the cathode side of the glass wall, corresponding to a library established in Turin since 1802, and still in business, well-known for publishing and selling educational material.

Dating probably to the middle third of the 20^th Century

13.5” (34cms) long with a 4” (10cms) bulb.

Concave aluminum cathode, partly discolored.

Rod type aluminum anode.

Anti-cathode and target of unknown material.

Regeneration by a cylindrical carbon inclusion freely moving in an accessory chamber.

Note the spherical “swelling” of the glass sleeve of the cathode arm, holding the cathode firmly in place inside the tube wall..

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