186 THE ELECTRIC TELEGRAPH. [CHAP. XIII 



ning, so frequent and vivid in this climate, without serious de 

 rangement of the delicate machinery. The telegraph generally 

 in use is the patent of Mr. Morse, whose invention combines the 

 power of printing a message simultaneously with its transmis 

 sion. As the magnetic force becomes extremely feeble when 

 conducted through a great length of wire, Morse employs it sim 

 ply to make a needle vibrate, and so open and close the galvanic 

 circuit placed in each office, where a local battery is set in mo 

 tion, which works the printing machine. The long wires, 

 therefore, may be compared to slender trains of gunpowder, 

 which are made to fire a distant cannon or mine. It is not the 

 battery in Philadelphia which works the instrument in Wash 

 ington, but a battery in the Washington office. This contrivance 

 is obviously nothing more than a new adaptation of the method 

 specified by Mr. Wheatstone, in his patent of June, 1837, for 

 ringing an alarum bell in each station by means of a local bat 

 tery, of which I saw him exhibit experiments in 1837. 



In September of the same year Mr. Morse invented an in 

 genious mode of printing messages, by causing an endless scroll of 

 paper to roll off one cylinder on to another by means of clock 

 work, the paper being made to pass under a steel pen, which is 

 moved by electro-magnetism. 



An agent of Mr. Morse explained to me the manner in which 

 the steel pen was made to indent the paper, which is not pierced, 

 but appears as if it had been pressed on by a blunted point, the 

 under surface being raised as in books printed for the blind. If 

 the contact of the pen be continued instead of making a dot, it 

 produces a short or a long line, according to the time of contact. 

 The following is a specimen : 



TheElectroMag netic 



Telegraph. 



In the latest improvements of the telegraph in England, the 

 magnetic force has been so multiplied by means of several thou 

 sand coils of wire, that they can send it direct, so as to move the 



