The times., 1897-04-25
PHOTOGRAPHIC MOTION.
Pictures Taken at the Rate-of Forty
in IA second.

In n second.
Everybody has seen moving Photographic
views exhibited as vitascopes, cineruaol-
graphs, biogfaphs or autographs, but very
few know how the IifeHke scenes are re-
produced from their originals. The scfen-
tific American devotes some space 10 de-
scribins the process by which photographic
pictures are made. The machine consists
OF a camera frame, mounted by means OF
| three adjustable legs upon a triangular
turntabie which may be placed upon
any suitable support. Upon the top OF ths
frame is bOlted a two-horse power electric
motor, which is driven by set of storage
batteries. The combination OF the turn
table with the vertical adjustment before
mentioned enables the camera 70 be shifted
SO as to take in the required field. In
the front end Of the Camera is fixed
particularly perfect lens. capable or
gathering a great flood Of light and pro-
ducing an image OF exceedingly clear de-
tail. Above this lens, on the front face
OF the camera, is fixed a Photographic
'finder,' which gives the same sized
image as the main lens. and enables the
operator 10 determine when the subject
is properly focused. Inside the camera is q
strip oi geIatine fIlm Two ana Ihree-guar,er
inches wide and usually about 100 feet in
length which is wound upon a small
pulley OF drum. The length OF the film
varies for different subjects, and, in case
OF a prolonged scene, it may extend to sew
erai thousands of feet.
The film is led through a series OF
rollers and caused to pass directly te-
hind the main lens of the camera, end
finally is wound upon a second drum.
The object of the rollers is to cause the
film to pass behind the lens with an
intermittent instead of continuous mo-
ton. At ordinary speed this would seem
to be a matter of simple accomplishment;
but when we remember that Impressions
are taken at the rate OF forty a second,
and that the film, which is running at
the rate of from seven TO eight feet a
second, mas TO be stopped and started with
equal frequency Il can be understood that
the problem was no easy one to solve.
The film comes TO a rest as the shutter
opens, phase or image is deposited, and
the film starts again as the shutter closes.
The impressions vary in actual exposure
between one-hundredth and one fOur-hun.
dredth of a second While the ordinary
speed is forty a second, the mutOSc0pe can
take equally good pictures at the rate
of 100 per second, If it is necessary. The
higher speed would be used In photo
graphing the flight OF a projeCtile or any
object that was in extremely rapid motion.
The mechanism within the cabinet Is
driven by betting from the motor abOvemen-
toned. and the speed OF the big motor is
controlled with great nicety by means OF
resistance box which is mounted upon ths
storage batteries.
After the ulutograph has done its work
upon the films they are carefully packed
and sent to the New York establishments
ofthe American Mutoscope Company, where
they are developed, fixed and used as mega
tives for printing the positive strips used
In the biograph or the bromide prints for
the mutOscope.
In displaying these views for public
representation it is necessary TO run the
film at the same speed at which it was
taken-a result which is obtained by the
use OF taChOmeter. When a subject
is to be thrown upon the screen a spool
containing the positive film is placed in
the cabinet, and run with an fntermit-
tent motion through the controlling roll
ers, down between the lamp and the lens,
and finally wound upon a receiving spool
When shown in a theater the whole
apparatus and the operator are usually
inclosed In a cabinet, which is located as
the back OF the balcony A hole Is cut
in the cabinet for the lens, and there is
a window for the operator. The pictures
are thrown upon large screen upon the
stage, and an express train running
at sixty miles an hour is one OF the
most vivid representations OF the kind ever
attempted d-PhiladcIphia Record.