Ludwig Prandtl,internationally known expert on aerodynamics, died in Germany on August 19th. He was seventy‐eight. During his life‐time, Professor Prandtl had been director of the Kaiser Wilhelm Institute for Fluid Motion Research and of the Institute for Technical Physics at the University of Goettingen. He was an honorary member of the American Academy of Arts and Sciences and the recipient, in 1930, of the Daniel Guggenheim Gold Medal for “conspicuous merit” in aerodynamics.