Hendrik Johannes van der Bijl (WECO, USA) developed this first WECO tube. It is also called peanut-tube for it's very small size. As Type N it has been finished in 1919 and was on market as 215A in the early 20ies - for nearly a decade.
H.J. van der Bijl deducted the fundamental functional relationships of triodes and by that won a post at the Western Electric Company (WECO) as Senior Research Phyicist until the publication of the book "Theory of the Tnermionic Tube and its Applications" in 1920. (EE)
The peanut-tube was also produced in Canada and ST&C (Standard Telephone & Cables, London) has produced the 215A as 4215A and as 4215AB with standard european socket.
