February 26 - Robert Watson-Watt and Arnold Wilkins first demonstrate the reflection of radio waves from an aircraft, near Daventry in England;[REF] on June 17, the first radio detection of an aircraft by ground-based radar is made at Orford Ness.
Jacques Yvon introduces S-particle distribution functions in classical statistical mechanics;[REF] they will later be included in the BBGKY hierarchy.