ON SOME MARVELS IN TELEGRAPHY. 373 



made at distant stations, not only can the same clock thus 

 keep time for two observers hundreds of miles apart, bu* 

 each observer can record by the same arrangement thf 

 moment of the occurrence of some phenomenon. For if 

 a tape be unwound automatically, as in the Morse instru- 

 ment, it fs easy so to arrange matters that every second's 

 beat of the pendulum records itself by a dot or short line 

 on the tape, and that the observer can with a touch make 

 (or break) contact at the instant of observation, and so a 

 mark be made properly placed between two seconds' marks 

 thus giving the precise time when the observation was 

 made. Such applications, however, though exceedingly 

 interesting to astronomers, are not among those in which 

 the general public take chief interest. There was one 

 occasion, however, when astronomical time-relations were 

 connected in the most interesting manner with one of the 

 greatest of all the marvels of telegraphy : I mean, when 

 the Great "stem in mid-ocean was supplied regularly 

 with Greenwich time, and this so perfectly (and therefore 

 with such perfect indication of her place in the Atlantic), 

 that when it was calculated from the time-signals that the 

 buoy left in open ocean to mark the place of the cut cable 

 had been reached, and the captain was coming on deck 

 with several officers to look for it, the buoy announced its 

 presence by thumping the side of the great ship. 



