In 1872, the former governor of California, Leland Stanford, was an avid race-horse owner with a problem. He had taken a position on a popularly debated question of the day — whether all four feet of a horse were off the ground at the same time while galloping. He thought they did.
But, the human eye cannot keep up the speed of the horse’s legs. To most people it appears as though the horse always had one hoof on the ground.
Stanford hired a photographer by the name of Muybridge for some photographic studies to solve this argument.
In 1872, Muybridge settled Stanford's question with a single photographic negative. Between 1878 and 1884, Muybridge perfected his method of horses in motion, proving that they do have all four hooves off the ground during their running stride.