Popular Science, October, 1922, page 63:
     Irving  Langmuir--Creator  of  the  Super-Tube     
Irving Langmuir and 20 kilowatt vacuum tube ALTHOUGH best known to the electrical industry as the inventor of the gas filled tungsten lamp, Dr. Irving Langmuir would, no doubt, call this achievement merely his first step in the development of the mighty 20-kilowatt vacuum tube--called the radiotron--a small cylinder of glass and metal, possessing power enough to transmit radio messages thousands of miles. Ten of these tubes--easily carried in one hand--are expected to replace huge generators weighing many tons.
    Doctor Langmuir was born in Brooklyn, N. Y., and after graduation from Columbia University as a metallurgical engineer spent three years in Germany at the University of Göttingen, where he was fortunate to study under Professor Nernst, inventor of the Nernst lamp. On returning to America in 1906, Doctor Langmuir became instructor in chemistry at Stevens Institute of Technology, and in 1909 entered the Research Laboratory of the General Electric Company at Schenectady, N. Y., where all of his valuable researches have since been carried on.
    Those who know him say that the spectacular successes of Doctor Langmuir are due primarily to his ever-present inquisitiveness. He has never been known to take a fact for granted. It was this quality that urged him on to the perfection of the super-radiotron after certain strange actions in the gas filled lamp had piqued his scientific curiosity.
    The 20-kilowatt tube--his latest contribution to radio science and designated by Marconi "the greatest development of the age"--contains a grid, a filament, and a plate. The filament is large and rugged and the plate, supplied with a direct current of 20,000 volts, is a metallic cylinder 8 inches long and 1½ inches in diameter, sealed directly into the glass of the tube.