THE ELECTRIC TELEGRAPH. 



Thus, for each swing of the anchor, the indicator makes one 

 motion forward, and as the escapement wheels have each only 

 four teeth at equal distances, one complete revolution of these 

 wheels must cause the indicators to make a complete revolution by 

 eight distinct motions, produced by the four swings of the anchor 

 to the right, and the four swings to the left. 



During a revolution of each of the escapement wheels, therefore, 

 each of the indicators takes successively the eight positions 

 required in the proposed system of signals, and since the motions 

 of the indicators are governed by the anchors, those of the 

 anchors by the armatures of the electro-magnets (154), and those 

 of the electro-magnets by the successive pulsations of the electric 

 current, it follows that if it can be contrived that commutators at 

 one of the stations shall govern the pulsations of the current at 

 the other, they will necessarily govern the motion of the indicators 

 at that other station. 



At the upper corners, right and left of the front of the case, are 

 two dials, in the centre of which are axes, which act, when turned, 

 upon the springs which draw back the armatures of the two 

 electro-magnets, and near them keys for their adjustment are sus- 

 pended by chains. The springs are raised or relaxed, according 

 as the keys are turned in the one direction or the other. 



Under the indicating arms are two axes with square ends, by 

 which the two systems of clock-work can be wound up, which is 

 done by the same keys. 



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