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that utilised in the camera and projector; the most simple design and operation, de-
because the film had to be advanced inter- manding the minimum of labour on the part
mittently beneath the punches, which were of the operator.
provided with an oscillating movement. This In the Williamson perforator, four holes on
type of machine is shown in the illustration. either side of the film are punched at one
Paul’s first appliance has always ranked as time, and two films are perforated simulta-
more simple, efficient, and reliable than any neously, the sensitised surfaces being face to
other. face. This arrangement obviates the danger
During recent years the rotary perforator has of scratching or rubbing the sensitised sur-
fallen from favour, on the plea that it soon face during the operation. One coil of plain
becomes imperfect in working; but such an film is mounted on the spool A, and another
accusation cannot fairly be brought against on the lower spool B. The leads from these
Paul’s machine, since its designer used it two spools are taken between the rollers C
continuously for four years, during which on to a small platform or guide gate D, where
time it punched millions of holes, and to-day the two superimposed films are brought ac-
is as correct In its work as when first used. curately together to pass under the punches.
These are mounted in two rows, the requi-
It is impossible within the scope of this site distance apart, in a moving head piece E,
book to describe all the various types of per- which descends at the critical moment, the
foration apparatus now in vogue, more espe- punches piercing the films cleanly and sharp-
cially as their interest lies mainly in highly ly, the pieces of detached celluloid falling
technical details. I will content myself with into a receptacle on the floor beneath.
describing three machines which exemplify
the three most important methods of perfo- When the head containing the punches rises,
ration. the two hooked fingers or claws F engage a
hole on either side of the films, and pull them
As this operation has to be carried out in the forward ready for the punching of the next
dark room in the dim light of a ruby lamp, it is four pairs of holes. In addition to carrying four
imperative that the machines should be of pairs of punches, the head E carries four pairs

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