paper. With the advent of flexible film, Thomas Edison quickly set out on his invention, the Kinetoscope, which was first shown at the Brooklyn Institute of Arts and Sciences on May 9, 1893. The Kinetoscope was a film loop system intended for one-person viewing. Edison, along with assistant William Kennedy Dickson, followed that up with the Kinetophone, which combined the Kinetoscope with Edison's cylinder phonograph. Beginning in March 1892, Eastman and then, from April 1893 into 1896, New York's Blair Camera Co. supplied Edison with film stock. Dickson is credited as the inventor of 35 mm movie film in 1889,652 when the Edison company was using Eastman film.653–654 The company still received film from Blair after this; at first Blair would supply only film stock that would be trimmed and perforated at the Edison lab to create gauge filmstrips, then at some point in 1894 or 1895, Blair began sending stock to Edison that was cut exactly to specification. Edison's aperture defined a single frame of film at four perforations high. Around 1896, a 35mm projector known as a "photo-rotoscope" was made by W. C. Hughes in London, which advanced the film by means of a "dog" motion. For a time, it had been generally assumed that Dickson was following cinematography formats established by Eastman in producing the film, but Eastman had produced film in sheets that were then cut to order.652–653 Dickson used the film supplied for Eastman Kodak cameras in 1889, a transparent 70 mm celluloid film, in his development of a more suitable film stock, and "simply slit this film in half";653–654 it was initially developed for the Kinetoscope, a one-person viewer, not to be projected.658 The image was still of high quality, even when magnified, and was more economical than 70 mm film (and more economical than any other gauge, as cutting the 70 mm to size would have created waste).654 35 mm was immediately accepted as standard by the Lumière brothers, and became the main film used in the UK because it was the stock sold to these filmmakers by the Blair company.653 Edison claimed exclusive patent rights to the design of 35 mm motion picture film, with four sprocket holes (perforations) per frame, forcing his only major filmmaking competitor, American Mutoscope & Biograph, to use a 68 mm film that used friction feed, not sprocket holes, to move the film through the camera. A