Bull (1876-1972) devised his stereoscopic spark drum camera in 1903. The camera took 54 pairs of pictures at up to 2000 frames per second and was the first to analyse the wing beats of insects. The insect was illuminated by a succesion of very bright electrical sparks, fired off by means of the rotary contacter at the side of the camera. The drum was driven at up to forty revolutions a second. Bull's photographs of a dragonfly's wings can be seen on the wall.
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