594 TRE APPLICATIONS OF PHYSICAL FORCES. [BOOK v. 



in position with either pin at the moment of passing, the respective 

 pin will rise through the hole and make a metallic contact with the 



FIG. 886. Whcntstone's automatic ' transmitter. 



battery, sending a current into the line in one or other direction, 

 according to the position of the perforation, and the rising of the 

 respective pin. If no perforation in the paper ribbon is in position at 



FK;. :-;$?. Whcatstone/s " dot " automatic ]>riiili 



the time of the automatic elevation of the respective pins, they fall 

 back by the compensating influence of adjusting springs, and a " mute" 



