ELECTKIC TELEGRAPH. 



nication, differs very much when one form of telegraphic instru- 

 ment or one pair of operators is compared with another. 



The profitable result of the operation of any telegraph is 

 evidently measured by the number of words which it is capable of 

 transmitting in such a shape as to be intelligible by the party to 

 whom the message is addressed, in a given time. This, which we 

 shall call the celerity of transmission, and which is quite distinct 

 from the velocity with which electric signals are conveyed from 

 station to station, is therefore a most important element in the 

 estimation of the value of any telegraphic apparatus. 



223. This celerity of transmission depends upon a great number 

 of circumstances, several of which are independent of the tele- 

 graphic apparatus. The principal of these are : 



1. The skill and agility of the transmitting agent. 



2. The quickness of eye, activity and attention of the receiving 

 agent. 



3. The instrument used for transmission. 



4. The instrument used for reception. 



5. The distance to which the dispatch is transmitted. 



6. The insulation more or less perfect of the line wires. 



7. The weather. 



With all and each of these conditions and qualities the celerity 

 with which the dispatches are received and rendered available at 

 their place of destination, varies, and with some of them this varia- 

 tion extends to very wide limits. 



224. Different telegraphists have very different powers as to 

 celerity. These powers depend on practice as well as upon 

 natural ability and aptitude, and on manual dexterity. Not only 

 is it necessary to transmit the signals in quick succession, but to 

 do so with such distinctness that they shall be readily interpreted, 

 and such correctness as to render repetitions unnecessary. In 

 this respect telegraphists having equal practice differ one from 

 another as much as do clerks, some writing rapidly and legibly, 

 some rapidly but not legibly, some legibly but not rapidly, and 

 some neither rapidly nor legibly. The relative ability of tele- 

 graphists in this respect is partly mental and partly mechanical, 

 depending as much upon quickness of intelligence, attention, and 

 observation, as upon manual dexterity and address. 



The great liability to delay, arising from the failure of the 

 transmitter to render himself understood by the receiver, is ren- 

 dered manifest by the fact that in all telegraphs conventional 

 signs are established for the words, "wait," "repeat," "not 

 understood," "understood," "proceed," and the like. When 

 the transmitter is going on faster than the receiver can take down 

 the words or understand them, then the latter remits the sign to 

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