Early Swett & Lewis Tube

Ref. B2

The Swett & Lewis Co., Boston, has existed as tube-makers for a few years only, from 1897 to 1902 (E.R.N.Grigg, The Trail of the Invisible Light, 1965, p 101), and the picture below is of an advertisement from an undated early catalog.

This early type two-electrode tube is 14” (35 cm) long with a 4” (10 cm) diameter oval bulb and has an internal structure fairly similar to that of the “Jackson Tube”.

The back of the aluminium cathode is etched with the name of the company and with a serial number 3004.

The platinum anti-cathode shows a melting crater due to overheating.