352 



PHYSICAL EXPRESSION. 



various movements. The electrical signals give 

 the means of marking time, indicating events, etc. 



" The electrical contact-making tambour " is re- 

 presented in Fig. 50. Across the ordinary shell 

 of a Marey's tambour, a main bracket, a, a, is 

 fixed, to which three smaller ones are screwed, 

 having holes in them to take two arbors. One 



Fig. 49. Frame supporting the recording tambours, and electrical signals. 



arbor, 6, has a beam, d, e, with a small weight at 

 one end, e, and is connected by a short link with 

 the india-rubber head of the tambour. To the 

 other arbor, C, a block of ebonite is fixed to insulate 

 two wires, /, g, with platinum ends, which lie under 

 and nearly touch the beam d, e. Each of these 



