CELERITY OF TRANSMISSION. 



11 wait," and if this sign is several times repeated, the necessity of 

 proceeding slower is apparent. If the receiver mistakes a sen- 

 tence, word, or letter, he remits the sign to " repeat." At the 

 end of each sentence, he remits the sign " understood," and so on. 

 Now it will be easily conceived that this necessity for frequent 

 interchange of signs between the receiver and transmitter must 

 affect, in an important degree, the celerity of transmission, and 

 that its frequency must depend, not only on the abilities of the 

 telegraphic agents, but also on the character of the signs trans- 

 mitted by the instruments, according as they are more or less 

 obvious and unequivocal. 



225. It is a remarkable and very curious circumstance, that, 

 independently of the mere celerity, clearness, and correctness 

 of transmission with certain telegraphic instruments each tele- 

 graphist has a manner and character, which is so peculiar 

 to himself, that persons receiving his dispatch at a distant 

 station, recognise his personality with as much certainty and 

 facility as they would recognise the handwriting of a corre- 

 spondent, or the voice and utterance of a friend or acquaintance, 

 whom they might hear speak in an adjacent room. The agents 

 habitually engaged at each of the telegraphic stations, in this 

 way, soon become acquainted with those of all the other stations 

 on the same line, so that, at tlje commencement of a dispatch, 

 they immediately know who is transmitting it. 



While the aptitude of the transmitter is partly manual or 

 mechanical, that of the receiver of a dispatch is not at all so. In 

 some telegraphic instruments, as we have seen, the presence of a 

 receiving agent is unnecessary, the dispatch being written or 

 printed by the apparatus itself. In all instruments, however, which 

 merely exhibit arbitrary signals, expressing letters, numbers, 

 or words, the celerity must depend on the skill, aptitude, and 

 quickness of eye of the receiver, to catch and commit to paper the 

 succession of letters or words, as fast as the signals expressing 

 them are produced before him. 



226. In general, it is much more easy to transmit rapidly than 

 to receive rapidly. The transmitter knows beforehand what 

 signs he is about to produce, while each of them comes upon the 

 receiver altogether unawares, and if, in the celerity of their suc- 

 cession, one or more of them escape his eye, he is obliged either to 

 guess at the missed letter or letters, which he can sometimes do 

 with all the requisite clearness and certainty, or he must arrest 

 the transmitter, which he does by giving the sign, " repeat," 

 and so delay arises. 



In telegraphs which work by a series of visible signs, whether 

 they be deflections of the needle, as in the English instruments, 



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