In March of 1882 Muybridge was in his native England and presented two showings of his photographs, illustrated with a projector which he called the Zoopraxiscope, borrowing the name almost entirely from Reynaud and the scientific data from Marey. Muybridge gave a lecture, “Attitudes of Animals in Motion, illustrated with the Zoopraxiscope,” at a special meeting of the Royal Institution of Great Britain, held on March 13, 1882, with His Royal Highness, the Prince of Wales, honorary member, presiding. The material was previously presented in a paper read before the Royal Society. Muybridge said, “The analyses of some of the movements investigated by the aid of electro-photographic exposures ... are rendered more perfectly intelligible by the reproduction of the actual motion projection on a screen through the zoopraxiscope.” The walk, trot, amble, rack, canter, run and gallop--which are the several gaits of a horse--were discussed at length with much emphasis on the physiological aspects. Figuratively, Marey must have been standing beside Muybridge as he talked. The lecture, virtually word for word, was given by Muybridge in February, 1833, at the Franklin Institute in Philadelphia. But it is significant to note that then there was no mention of the Zoopraxiscope. Muybridge evidently was not a good operator and there seems to have been difficulty with the projector. Operation of the projector was a problem then because there had to be a relation between the number of pictures and the slits in the projection shutter. Muybridge seems to have found it all too much trouble and turned to the task of taking successive stills which could then be made up into handsome illustrated books. Meanwhile, Marey in the Spring of 1882 finally finished work on his Photographical Gun which he had conceived several years previously. By this time Marey had a large open air studio set up in the Bois de Boulogne. (Illustrations facing page 121.) Marey said that he had worked twelve years on the general subject of movement, thereby placing his first efforts back in 1870. The “beautiful instantaneous photographs of Muybridge proved his work,” he declared. He continued, saying that in 1878 he had the idea of a photographic gun somewhat analogous to the astronomical revolver of Janssen. Finally, he resolved to devote the Winter of 1882 to the realization of the project. Marey used his gun to study his favorite project of birds in flight. Marey’s photographic gun was the first practical motion picture camera, primitive and limited though it was. In this sense it was the original of all newsreel and other portable motion picture cameras. It is worth noting that in our own time cameras are mounted as “photographic guns” in airplanes as a substitute for gunnery in peacetime and as a check on results during war.