edward muybridge

On June 15, 1878, a clear and sunny day in Palo Alto, California, amid a gathering of art and sports journalists, Eadweard Muybridge photographed the first successful serial images of fast motion.
The subject of these photographs was the trotting horse, Abe Edgington, harnessed to a sulky. The horse was owned by railroad builder and former governor, Leland Stanford. Proven was Stanford's theory that during a horse's running stride, there is a moment of suspension where no hooves are touching the ground.

http://photo.ucr.edu/photographers/muybridge/