1882.] 



on Animals in Motion. 



47 



Fig. 2. Back view of electro-exposor. Two shutters PP, eacli 

 comprising two panels, with an opening O between them, are adjusted 

 to move freely up and down in a frame ; they are here arranged ready 

 for an exposure, and are held in position by a latch L and trigger T, 

 all light being excluded from the lens. A slight extra tension of 

 the thread B, Fig. 4, will cause a contact of the metal S23rings M S, and 

 complete a circuit of electricity through the wires W W and the 

 electro-magnet M ; the consequent attraction causes the armature A 

 to strike the trigger, the latch is released, the shutters are drawn 

 respectively upwards and downwards by means of the rubber springs 

 S S, and light is admitted to the sensitised plate while the openings 

 in the shutters are passing each other in front of the lens. 



Fig. 3. Front view of electro-exposor after exposure of the plate. 



Fig. 5. General view of studio, ojDcrating track, and background. 

 In the studio are arranged 24 photograj)hing cameras at a distance 

 of 12 inches from the centre of each lens ; an electro-exposor is 

 securely fixed in front of each camera. Threads 12 inches apart are 

 stretched across the track (only two of which are introduced in the 



Fig. 5. 



engraving), at a suitable height to strike the breast of the animal 

 experimented with, one end of the thread being fastened to the back- 

 ground, the other to the spring. Fig. 4, which is drawn almost to the 

 point of contact. 



The animal in its progress over the track will strike these threads 

 in succession, and as each pair of springs is brought into contact, 

 the current of electricity thereby created effects a photographic 

 exposure, as described by Figs. 2 and 4 ; and each consecutive expo- 

 sure records the position of the animal at the instant the thread is 

 struck and broken. 



For obtaining successive exposures of horses driven in vehicles, 

 one of the wheels is steered in a channel over wires slightly elevated 

 from the ground ; the depression of each wire completes an electric 

 circuit, and effects the exposures in the same manner as the threads. 



