Sallie Gardner at a Gallop

Sallie Gardner at a Gallop, also known as The Horse in Motion, is a series of photographs consisting of a galloping horse, the result of a photographic experiment by Eadweard Muybridge on June 15, 1878. Sometimes cited as an early silent film, the series and later experiments like it were precursors to the development of motion pictures. The series consists of 24 photographs shot in rapid succession that were shown on a zoopraxiscope. It was released throughout 1878–1880. Muybridge was commissioned by Leland Stanford, the industrialist and horseman, who was interested in gait analysis. The purpose of the shoot was to determine whether a galloping horse ever lifts all four feet completely off the ground during the gait; at this speed, the human eye cannot break down the action. The photographs showed that all four feet are indeed sometimes simultaneously off the ground, though this occurs only when the feet are "gathered" beneath the body, not when the fore and hindlimbs are "extended" as sometimes depicted in older paintings.