Ch. XI]
MOVING PICTURE APPARATUS
401
supplying the power. Some power companies object to the use of
an inductor (choke-coil). In such cases a transformer can be used
instead.
§ 563. Stand or table.—A stand or table is provided by the
makers of the machine. The method used to set up the stand will
be fairly obvious from the illustrations furnished by the makers of
the particular machine used. Generally this stand is made of
brass tubes. One maker provides a heavy iron pillar. With this
make provision must be made to anchor this pillar firmly to the
floor.
If the machine is to be installed permanently, it is often better to
use a stand constructed of concrete or a very heavy wooden table
instead of the light stand regularly supplied. A very slight motion
of a rickety stand will cause an enormous movement of the picture
on a screen 15 to 30 meters (50 to 100 feet) away.
§ 564. Unpacking.—The moving picture machines coming from
the factory are very carefully packed. When removed from the
box, it is advisable to take careful notes of just how the different
parts are packed and to number the wooden cleats used to hold
things in place, especially if the machine will need to be shipped
away again.
Be careful in unpacking all parts, especially the lenses. Do not
throw away any wrapping material until sure that no parts are
missing.
§ 565. The moving picture machine.—When unpacked the
moving picture machine will be found to consist of a stand and base¬
board, arc lamp, lamp-house, condenser, aperture plate, objective,
shutter, film magazines, and mechanism for moving the film.
There will also be an extra film reel and a rewinder (fig. 221- 224).
§ 566. The arc lamp.—The arc lamp usually supplied with
moving picture outfits is of the hand-feed type with inclined car¬
bons. The handles for feeding the carbons and for slight up and
down adjustments project backwards so they may be manipulated
without opening the lamp-house. The good makes of arc lamp are
adjustable so that the carbons can be held in the vertical or the