The remarkable Dr. Hendrik van der Bijl

The article contains biographical information about this South African physicist who while continuing his studies in Germany investigated photoelectric emission using an apparatus with a photocathode, an anode, and a grid similar to de Forest's Audion. He established the behavior of this three-element system and subsequently extended the analysis to apply to the thermionic triode at the Western Electric Laboratories in New York. He used this knowledge to design many of the first tubes used in radio and telephony; he invented the grid modulation system for radiotelephony and wrote the first textbook on the vacuum tube in 1920. Soon afterwards he returned to South Africa as Scientific Advisor to the Government and created a countrywide electricity supply network, a world class steel corporation, and numerous other important industrial enterprises.