590 THE APPLICATIONS OF PHYSICAL FORCES. [BOOK v. 



the same moment. Now this letter, at each passage of the current, is 

 precisely the same as that on the key pressed down which raised the 

 pin into the hole of the disc D and the piece of the chariot passing 

 above. The letter is printed in passing as we may say, as the type- 

 wheel moves continuously. The three other cogs of the printing- 

 shaft serve as follows : the first in the form of a helix, to depress the 

 lever JU, which carries the catch r and moves on the ratchet wheel E 

 by one tooth and so the band of paper ; the next cog works in the teeth 

 of the correcting wheel, so as to put right the stoppage, losses, or 

 gains of that wheel, and to preserve the complete accordance between 

 the type wheel and the chariot, and the last cog is to adjust the 

 apparatus to the starting point, that is, the blank space on the type 

 wheel. 



Fro. 383.- Printing nianliinery in Hnglies's system. 



The way of proceeding for sending off a message is this : the 

 clerk at the sending station, to attract the attention of the station on 

 the line to which the message is to be sent, raises the break of the 

 fly-wheel of the clockwork and sets it in motion, then he depresses 

 the white key which moves the alarum in the receiving station. The 

 clerk here, on receipt of this warning puts his apparatus in motion, 

 and the two clerks together pressing on the pedal Q regulate their 

 apparatus, that is, put their type-wheels to blank ; they then test 

 the synchronism by repeating a certain number of times the same 

 letter, A for example. If the velocity is the same, that letter is always 

 repeated again and again, if not, and the letter before or after takes 

 its place, it shows one is faster than the other. The regulation is 



