276 AMERICAN ELECTRIC-TELEGRAPH. 



ofinferior coinlucting power. The thick iron wires, being stronger and 

 less liable to be broken, are about to take the place of copper on some 

 of the telegraphic lines. - For conveying intelligence both ways there 

 must be an electro-magnet at each end of the line, although one battery 

 is sufficient. One battery is even sufficient to operate two independent 

 circuits, by which communications can be sent both ways, at the same 

 time. For this purpose it is only necessary to have two wires, the 

 ground being used in common with them. In this case the electricity 

 divides itself between the two wires into two currents, rendering the 

 U's at each end magnetic, and returning through the ground to the 

 battery. 



When no intelligence is to be conveyed the wire is not in close con- 

 nection with the battery, but with a spring key. The connection with 

 the battery and the transmission of the current is secured by pressing 

 down the free end of the key until it touches a knob in connection with 

 the battery, and as long as the contact is continued the current flows. 

 As soon as the operator removes the pressure of his finger, the key ri- 

 ses, contact is broken, and the current ceases to flow. Thus a current 

 and consequently magnetism of longer or shorter duration may be se- 

 cured according to the will of the operator. 



As soon as the connection is formed by the operator at one end of 

 the line, by pressing down his key, the \J at the other end becomes 

 magnetic, and attracts down to it a piece of soft iron, stretching from 

 side to side and distant from it about one-eighth to one-tenth of an inch. 

 This soft iron, called the armature or keeper, is attached to one end of 

 a lever, which it brings down, whilst the other end, which is furnished 

 on its upper surface with a blunt steel point called the pen, is by the 

 sjame motion forced upwards. Directly opposite the pen is a small 

 groove in a small cylinder placed above it. Between this cylinder and 

 the pen a ribbon of strong paper is drawn, by a kind of clock work, 

 which is put in motion as soon as the \J becomes magnetic. When 

 therefore the pen is forced upwards it indents the paper by pressing it intcy 

 the groove, and makes a mark, wiUiout tearing, according to the length 

 of time during wiiich tlic o[)crator at the other end holds down his key. 

 It" he inuiicdiulcly lets it rise, the pen makes a dot, if he holds it down 

 longer, it will make a line, kc. fn this way lines or dots or their com- 

 bination may be made at j)lcasure. 



The great superiority of Prof Morse's telegraph consists mainly in 

 tlie simplicity of his alj)habet and the case with which the characters 

 arc recorded. His alpliabel, which he also invented on his homewaid 

 ))assagc, conijiol:: ol dots and lincij and then ouinbiuutiun, and is udniiia- 



