26 



THE MECHANISM OF 



cells. At the studio they were placed on shelves in the camera- 

 liouse at I in Fig 1. A wire from the negative pole of the 

 battery carried the current to the binding-post U, while a wire 

 from P, R, carried it back to the positive pole. In the circuit of 

 this return wire the electro-magnet e, m, of the chronograph was 

 placed, and by the arrangement a style fastened in its armature 

 traced a record on the lampblacked paper covering the drum J 



Fig. 2. 

 ANIMAL LOCOMOTION. 



WAGRAMDF-fLECTRlCALCONNECTiONSI^ORMAKWGCONSECLmvEl'HOTOERAPHIC 

 EXPOSURE SSrNCHRONOUSLYTROMSEVERALJ'OINTSar-VIEW 



MCCHANI9M rOR SIAFTUG 

 CONTACT-BRUSH 



LfTiotdir,illa.d 



whenever the armature was drawn down by the passage of the 

 current, — simultaneously with the commencement of each exposure 

 in a series of twelve or twenty-four. While this record was being 

 made a time record was made directly under it by a style from 

 the electro-magnet t, m, in circuit with a tuning-fork, T. The 

 tuning-fork used throughout the investigations was pitched to one 

 hundred single vibrations per second, the vibration being main- 

 tained by a separate electric battery of two cells. The drum J 



