While the majority of films are made for purposes of entertainment, the moving picture has an extensive use in the commercial world by salesmen of machinery and mechanical ap pliances, who are thus enabled to show their products at work in any part of the country where they may fill a need. Much educational work has been done with the aid of the films; manufacturers have used them to display fash ions in dress; social organizations for the spread of their peculiar propagandas; and charitable institutions to arouse interest in their work. In scientific research it has also played a large part. The combination of the microscope and the moving picture camera has revealed an entirely new field of interest in the invisible world. The growth of plants has been studied by a series of exposures lasting over several weeks in the opening of a flower, and covering months in the growth of a stalk of corn. In securing these films the exposures are not made continuously as in ordinary camera work. In the case of the corn, which may take 90 days to mature, the separate exposures are made at such intervals as to give a film of perhaps 2,880 pictures in all, which will occupy the screen for just three minutes in its exhibition. The tele photo lens has also been combined with the moving picture apparatus, permitting pictures to be taken at a distance from the subject. Thus the actions of wild birds and animals have been recorded. Some of the most interesting films have shown the emerging of the butter fly from its chrysalis; the silkworm spinning its cocoon; a snake shedding its skin; a war of enemy tribes of ants; and many such incidents.
A very important application of the moving picture idea is the study of the movements of highly skilled mechanics at their work, particu larly in factories. A tiny electric light is at tached to the hand, or other moving part, and its trace on the moving picture film affords a diagram from which wire forms or guides are constructed. Unskilled workmen are taught by these forms to learn the motion which gives greatest efficiency in production. The introduc tion of a clock into the picture permits the measurement of the actual time consumed in making each movement or part of a movement, with the accuracy of one-millionth part of an hour. The moving picture camera has also been
used to study the movements of expert type writers and piano players. In surgery it is used to observe defective or abnormal motions after operations; and the makers of artificial limbs use it to secure the nearest possible counter feit of the normal movements of sound mem bers.
The moving picture business has settled into a triplex organization: (1) the producers of the picture films; (2) the exchanges, or distributing middlemen; (3) the exhibitors. In the United States in 1915 there were 248 firms and studios registered as film producers; 1,364 exchanges; and 15,046 exhibiting houses of all types. The recent tendencies have been toward the com binations of the larger producing companies, and the establishment of the new combines of branch houses throughout the country, acting as distribution centres. And many of the former middlemen have become producers on a small scale.
Figures as to the attendance at the moving picture theatres cannot be given with any de gree of accuracy. The number of the smaller houses, those seating about 300, is constantly diminishing, but the continued building of larger houses keeps the seating capacity about the same as in the days of the multitudinous '
A considerable factor in the business of pro ducing films is the large export trade. In spite of the many difficulties in such traffic on ac count of the war, the high-water mark in film exportation was reached in 1916, when 136,141, 137 feet of film pictures, valued at $6,051,031, were sent abroad.
Bibliography.— American Motion Picture Directory, 1914-15; Bennett, C. N., 'The Hand book of Kinematography' • (London 1911) ; Croy, 'How Moving Pictures are Made' (New York 1918) ; Dench, E. A., 'Making the Movies' (New York 1915) ; Hulfish, D. S., 'Motion Picture Work' (Chicago 1915) •, Jones, B. E., The Cinematograph Book' (London 1915) ; Lomas, H. M., 'Picture Play Photography' (London 1914) ; Talbot, F. A., Practical Cine matography and Its Applications' (London 1913) ; Horstmann, H. C. and Tousley, V. H., 'Motion Picture Operation' (Chicago 1914).