68 THE ELECTRIC TELEGRAPH. 



a tooth behind, the clockwork turns the wheels and pointer 

 another one twenty-sixth. Thus every time the circuit is 

 made or broken, the pointer advances one of the twenty-six 

 divisions of the dial. 



The spring for drawing the armature from the poles is 

 adjusted by means of a bent lever, t, on the end of which it 

 is hooked. The lever itself is fixed to the under side of a 

 disc, s y turning on the vertical axis h. On the opposite side 

 of the disc s is a long vertical pin, i y which is gradually 

 turned with the disc in a small angle by an inclined plane on 

 the rim of the drum u. 



The shaft a, with its pallet and fork, is supported by a 

 frame or lever, c D, turning on the centre c on the left, and 

 on the right held up by a spiral spring which forces it against 

 a pin, passing through the guides M and N. On pressing 

 upon the button E of the pin, the frame is moved down- 

 wards and releases the escapement-wheels from the control 

 of the pallet, but carries down with it a check which prevents 

 their unlimited run. As soon as they are free to rotate, the 

 wheels turn round with the pointer until their further pro- 

 gress is arrested by the check which catches hold of a pin at 

 the back of one of the scape- wheels, corresponding in posi- 

 tion with the zero or + of the dial. 



The alarm generally used with this instrument contains 

 no new principle whatever. The attraction of an armature 

 liberates a clockwork, which turns a disc with an eccentric 

 crank. The latter in revolving moves the hammer of a bell 

 to and fro. It is similar in construction to Wheatstone's 

 first alarm. 



Another alarm which Breguet has supplied with some of 

 his telegraphs is constructed on the principle of the self-acting 

 make-and-break employed in Dr. "Werner Siemens's first 

 dial-telegraph. 



The connections of the apparatus for a station will be seen 

 by reference to Fig. 35, which shows the various pieces of 

 the apparatus. 



When neither of the stations is using the line the switches 

 N and N' of both the apparatus are placed on s and s', so that 



