INSTANTANEOUS PHOTOGRAPHY. 



19 



of stout rubber bands, B, the duration of the exposure being 

 varied at will by the thickness and number of bands used. 

 Firmly fastened to the front of the curtain is a wooden pin, C, 

 to which are attached a strong tape, D, with a ring in the end of 

 it, and another pin, F, over which the rubber bands B are passed. 

 The releasing magnet consists of an electro-magnet, M, whose 

 armature is fastened to the lower end of an arm, I, pivoted at H, 

 and having a shoulder on 

 its upper end that may be 

 placed over the extremity 

 of a three-inch steel lever, 

 G, and automatically held 

 there by the pressure of the 

 band-spring S. The lever 

 G is pivoted at a point 

 about three-sixteenths of 

 an inch from its back end, 

 in which is a slight groove 

 or indentation. To set the 

 exposor previous to making 

 a photograph, the front end 

 of G is caught under the 

 shoulder on I, the hold 

 (usually very slight) being 

 regulated by the set-screw 

 N ; the ring in D is placed 

 over the back end of G, and 

 the rubber bands B are then 

 stretched to the required 

 tension by pulling upward 

 on the end of a stout cord 

 passing under the pulley P 

 until the ring in the end of the cord can be caught on a hook in 

 the frame of the exposor. A plate is put in the camera and it is 

 ready for action. 



At the proper instant, by means of automatic apparatus to be 

 described farther on, an electric current is sent through the coils 

 of the magnet M ; the armature is pulled towards it, thereby re- 

 leasing the lever G, and the rubber bands, no longer restrained, 



