60 



THE ELECTRIC TELEGRAPH. 



attached to it is a ratchet-wheel, in the teeth of which catches 

 a click affixed to a movable piece, b 1} terminating in the 

 rectangular arm & 2 , which is forced upwards by a spring 

 attached to the frame of the apparatus, but is stopped against 

 the axis i. When i makes one revolution, the cam lifts 

 the arm b of the lever, together with the cylinder a and 

 paper strip up to the lowest tooth of the type- wheel by 

 which the paper strip is impressed with the print of the 

 type, kept inked by an inking roller, M. The cam being 

 very sharp, the movements of ascent and descent are pro- 

 portionally rapid, and the paper touches the type during 

 only an infinitely short space of time. The axis continuing 

 to turn, the cam meets the arm b and depresses it, causing 

 the click to draw round the cylinder and advance the paper 

 a certain distance. 



By the side of the ratchet-wheel i the printing shaft 



Fig. 31. 



carries an escapement h ti, arrested by a continuation of the 

 lever L L', moving with the armature of the electro-magnet. 

 The armature is of soft iron, supported at the extremity of a 

 lever D over the poles of the electro-magnet Fig. 31. The 

 lever turns between supports on the axis, and tends to rise 

 by the force of a spring regulated by the adjusting screw D'. 

 The screw d' (Fig. 32) on the end of the lever L L', turning 

 on the axis /, sits over the armature ; the other end of the 



