THE ELECTRIC TELEGRAPH. 



of foreign towns, or, in fine, from the inaccuracy or slowness of the 

 transmitting clerk in London. It would seem, therefore, that this 

 series of messages includes fair conditions for an average result. 



It would, therefore, appear that the needle instruments worked 

 by the magneto-electric current used by this company are, ceteris 

 paribus, susceptible of greater celerity of transmission than the 

 instruments in which the needles are affected by the common 

 voltaic current, in the ratio of about 27 to 21, or 9 to 7. 



One of the causes which has been assigned to this increased 

 efficiency, is the fact that the needles of the magnetic instruments 

 have a dead beat, while those of the voltaic instruments, in strik- 

 ing the stops, have a recoil, and vibrate two or three times before 

 they come to rest. Whether this be the real cause of the differ- 

 ence, further experience must prove, but it is difficult to imagine 

 that it can be due to any cause independent of the instruments, 

 seeing the large number of messages from which the average has 

 been computed. 



