THE 



SCIENTIFIC PAPERS 



OF 



SIB WM. SIEMENS, F.K.S 



ELECTRICITY. 



ON AN IMPROVED ELECTRIC TELEGRAPH. 

 BY C. W. SIEMENS.* 



A PAPER on an " Improved Electric Telegraph by Mr. E. W. 

 Siemens " was read and its action illustrated by a pair of working 

 instruments. 



Each instrument consists of an electro-magnet between the 

 poles whereof an armature oscillates. Connected with the arma- 

 ture is a lever, which being armed with a spring catch and an 

 arresting pin causes a cogged wheel to revolve through the breadth 

 of one tooth for every oscillation of the armature. 



The spindle of the cogged wheel carries on its upper end a hand 

 or pointer which revolves upon a dial plate consisting of a number 

 of keys marked with the letters of the alphabet. An insulating 

 brass piece is fixed upon the oscillating lever, which by striking 

 against two opposite flaps of a second metallic lever moves it a 

 little both ways, which movement is limited by two insulated set 

 screws, the object of which is to break and restore the current 

 alternately by establishing a contact between the second lever and 

 one of the set screws. 



The return stroke of the armature is effected by means of an 



* Extract from Minutes of the Society of Arts, May 30, 1849. 



B 2 



