M. Audra, in the name of M. Braun, of Angoulême, has presented to the Photo
Society of France a new instantaneous shutter. The shutter is formed by a
revolving metallic disk out of which a segment has been taken. This disk is
placed in the center of the diaphragms, in order to obtain the greatest
rapidity combined with the least possible distance to travel. On the axis
to which this circular disk is fixed is a small wheel, to which is attached
a piece of string, and when the disk is turned round for the exposure the
string is wound round the wheel. If the string be pulled, naturally the
disk will revolve back to its former position so much the more quickly the
more violently the string is pulled. M. Braun has replaced the hand by a
steel spring attached to the drum of the lens (Fig. 2) By shortening or
lengthening the string, more or less rapid exposures may be obtained.
[Illustration: AAA, lens; B, aperture of lens; C, metallic disk; D,
wheel on the axis; E, cord or string; E¹E¹E¹E¹, knots in string; G, steel
spring; H, catch; K, socket for catch.]
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