Abstract

Amateur scientists who traveled from town to town in the mid-nineteenth century delighted audiences by showing them the ancestor of the neon sign: the air was pumped out of a glass tube with platinum wires embedded in opposite ends, and the interior was made to glow in lively patterns when a high voltage was run across the wires. Transfixed by the fluorescence, the lecturers had however absolutely no idea what caused the electrical excitation in the vacuum tube.

[Optical Society of America ]