Paul Dupont Stroborama, c. 1925. Measurement of the bending of the tip of a propeller blade (photograph to the millionth of a second). Issy-les-Moulineaux wind tunnel. Vintage silver print. Printed caption Stroborama type A. Photograph to the millionth of a second of a 1m80 diameter propeller rotating at 2,400 rpm. Blade tip speed: 226 meters/second on verso. 17.9 x 12.9 cm This perfectly still image of a propeller spinning at very high speed illustrates the chronophotographic experiments of the 1920s in Raymond Lecuyer's Histoire de la photographie (1945).