Muybridge described the events leading to his images of horses in motion:
“In the spring of the year 1872, while the author was directing the photographic surveys of the United States Government on the Pacific Coast, there was revived in the city of San Francisco a controversy in regard to animal locomotion, which we may infer, on the authority of Plato, was warmly argued by the ancient Egyptians, and which probably had its origin in the studio of the primitive artist when he submitted to a group of critical friends his first etching of a mammoth crushing through the forest or a reindeer grazing on the plains.
In this modern instance, the principal subject of dispute was the possibility of a horse, while trotting- even at the height of his speed – having all four of his feet, at any portion of his stride, simultaneously free from contact with the ground…
Having constructed some special exposing apparatus… the author commenced his investigation on the race track at Sacramento, California, in May 1872, where he in a few days made several negatives of a celebrated horse named Occident, while trotting laterally, in front of his camera…
The photographs resulting from this experiment… exhibited the horse with all four of his feet clearly lifted, at the same time, above the ground.”
Eadweard Muybridge, “Preface,” Animals in Motion (New York: Dover Publications, 1957), p. 13.
Muybridge explained the significance of his discovery:
“It is impressed on our minds in infancy that a certain arbitrary symbol indicates an existing fact; if this same association of emblem and reality is reiterated at the preparatory school, insisted upon at college, and pronounced correct at the university; symbol and fact- or supposed fact – becomes so intimately blended that it is extremely difficult to disassociate them, even when reason and personal observation teaches us they have no true relationship.
So it is with the conventional galloping horse; we have become so accustomed to see it in art that it has imperceptibly dominated our understanding, and we think the representation to be unimpeachable, until we throw all our preconceived impressions on one side, and seek the truth by independent observations from Nature herself.”
Eadweard Muybridge, “The Gallop,” Animals in Motion (New York: Dover Publications, 1957), p. 57.