Inventions in 1929 31st President: Herbert Hoover March 4th 1929 - March 4th 1933 Republican 1929 Cord L-29 Phaeton Air traffic control | Freon | Flight simulator | Sunglasses | Frozen food | Particle accelerator | Electro-encephelograph (EEG) | Kinescope (CRT) |   Photo: Chris J. Moffett Photo: Elzie Crisler Segar The