ASTRONOMICAL USES OF THE TELEGRAPH. 



be determined. The Astronomer Royal proposes to use the " cen- 

 trifugal or conical-pendulum clock" as an instrument superior in 

 every way to those used in America; and "considering the 

 problem of smooth and accurate motion as being now much nearer 

 to its solution than it had formerly been, it might be a question 

 whether, supposing a sidereal clock made on these principles to be 

 mounted at the Royal Observatory, it should be used in commu- 

 nicating motion to a solar clock." 



It is worthy of remark also, that punctures can be made upon 

 the same revolving barrel by observers employed at two or more 

 instruments erected in different rooms, by means of keys or 

 commutators, which complete the circuit from the same battery 

 to the same puncturing-point. This is at present done with two 

 instruments at Greenwich. All necessity for comparing clocks is, 

 of course, avoided. 



Some difficulties occurred at first in imparting to the cylinder a 

 sufficiently smooth and equable motion, the motion given by com- 

 mon clock-work being always one made by starts like that of the 

 seconds' hand of a pendulum. It was to surmount this difficulty 

 that the Astronomer Royal proposed the substitution of the centri- 

 fugal pendulum (resembling the governor of a steam engine) for 

 the ordinary oscillating pendulum. In the report of the Astro- 

 nomical Society, published in February, 1854, it was announced 

 that "The various difficulties which occurred from time to time 

 in the mechanism of the barrel or smooth-motion clock, used for 

 giving motion to the cylinder on which will ultimately be 

 recorded the transits made with the transit-circle and altazimuth, 

 according to the American method of self-registration, have been 

 overcome. It now carries the cylinders put in connection with it 

 with perfect regularity, its rate having all desirable steadiness." 



TELEGRAPHIC LINES OF THE UNITED KINGDOM. 



271 . The telegraphic lines established throughout these countries 

 have been constructed altogether by private companies, chartered 

 or incorporated by the legislature. The total extent of lines in 

 actual operation in the beginning of 1854, was a little more than 

 8000 miles, upon which about 40000 miles of conducting wire 

 were laid, which would give an average number of five conduct- 

 ing wires over the entire telegraphic net- work. 



272. This vast machinery of electric communication has been 

 erected by five or six different companies, but the chief part of it 

 by two the Electric Telegraph Company, and the English and 

 Irish Magnetic Telegraph Company : the former possesses nearly 



103 



