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CHAPTER VI THE STORY OF THE PERFORATION GAUGE We have seen that before the film can be used in the camera it has to be perforated on either side in order that successive areas of film f of an inch deep—the equivalent of a picture—can be seized and brought into position behind the lens. This perforation has become stan- dardised in accordance v/ith. what is known as the '" Edison Standard Gauge," which is 64 perforations per foot on either side. This perforation is of an elongated form, measuring about i /8 of an inch in width by approximately i/i6th of an inch in depth. The preliminary operation is carried out with a machine, which stamps the holes by means of specially hardened steel punches. -Extreme care has to be taken to carry out the task with mathematical accuracy, in order that the film may be used with any type of camera and projector. Without it steadiness of the picture upon the screen is absolutely impossible. It seems strange that all films should have to be per- forated according to the Edison system, when it is remem- bered that the first commercial cinematographic apparatuses for the projection of pictures upon a screen were made, not by Edison, but by Paul and Lumi^re, who, one might think, would have established their own gauges. This important point involves an interesting little story. In the very earliest days of cinematography, when a film of greater width was used than at present, it was advanced by friction. Rollers, or clutches, gripped the edges of the film tightly, and moved it forward the desired