Photograph of the camera machine used by Eadweard Muybridge during his experiments in action photography, ca.1875. A large shed is pictured at center, into which a long opening has been made. Twenty-four cameras are visible arranged inside, numbered above on the building from right to left. An apparatus of wire, track and posts is visible on the ground in front of them.; Picture File Card quotes from Beumont Newhall's History of Photography: "Strings attached to electric switches were stretched across the track--the horse, rushing past, breasted the strings and broke them, one after the other--the shutter released by an electro-magnetic control, and a series of images made.", and "Drawings from Muybridges photos were pasted on strips and viewed in a mechanism known as a Zoetrope, a precursor of motion pictures. It was a topless drum which flipped on it[s] side, mounted on a spindle so that it could be twirled. Drawings showing successive phases of action placed inside the drum, and viewed through the slits were seen one after the other, so quickly that the images merged in the mind to produce the illusion of motion. In 1880, using a similar technique with a device he [called] the Zoopraxiscope, Muybridge projected his pictures on a screen at the Cal. School of Fine Arts, San Francisco and produced the first motion pictures.".