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218 Motion Pictures in Education narrow widths obtains any permanent footing in school work. They possess the one great advantage over the standard slow-burning film of much lower cost. Austin C. Lescarboura, Managing Editor of The Scientific American, writes regarding inflammable ver- sus slow-burning film: The usual professional standard film has a celluloid base, or, to use the language of the chemist, it is made from nitro- cellulose stock. This material is little different from gun- cotton, and as such it is of course highly inflammable. Still, there is no reason why the careful operator should have any trouble with celluloid film. Our leading theatres handle mile after mile of film each working day, yet never experience any trouble with the highly inflammable material they are handling. Celluloid film will not blaze up by itself; a blaze or intense heat must be applied for a period sufficient to start a blaze. The majority of projectors today are so designed as to re- duce the fire hazard to an absolute minimum, being equipped with such safeguards as automatic shutters, which drop down in the path of the source of light when the speed of the machine drops below a predetermined point; fireproof maga- zines which hold the film reels, and fireproof traps through which the film passes in and out of the magazines. At worst only a few feet of film, which happens to be exposed between the upper and lower magazines of the usual projector, can burn, causing little or no damage. The greatest hazard connected with the use of inflammable films is while the films are not in actual use. The inveterate smoker is a positive nuisance where films are being un- packed, examined, rewound or otherwise handled. In fact, film should always be kept in cans until it is actually about to be placed in the projector. There is no excuse for having a film fire if ordinary care is exercised. Of course it cannot be denied that there must be a certain sense of security that goes with slow-burning film. Such film is made of an acetate-of-cellulose stock, which, unlike celluloid, burns quite slowly if at all. If a match or great heat is applied to celluloid, it immediately flares up with a hot, rapid flame. The slow-burning stock, on the other hand, be- gins to burn if one is persistent, and then only with a weak and lazy flame which generally dies out as soon as the source of the fire is removed.