APPLICATION OF THE ELECTRIC TELEGRAPH. 339 



of the station at Macon. After successful exchanges of 

 signals on three different nights, Messrs. Dean and Grood- 

 fellow interchanged stations, and obtained exchanges on 

 three more nights with satisfactory results. The series 

 of astronomical observations extended from December 

 30th to March 16th. The clocks employed were adapted 

 to the chronographic method of observation by Mr. 

 Saxton. The spring governor and Kerrison regulator 

 were used for the chronographic registry of the transit 

 observations; but during the exchange of telegraphic 

 signals, an ordinary Morse register was also employed 

 at each station, and was found to give results com- 

 parable in accuracy with either of the former, owing to 

 the greater length of the seconds as recorded upon the 

 fillet, and to the general uniformity maintained during 

 any change of rate. 



During the winter of 1855-6, a comparison was made 

 between Wilmington, N. C., and Columbia, S. C., by means 

 of a new telegraph line, which gives one determination of 

 longitude between Petersburg and Columbia by the way 

 of Kaleigh, and another by the way of Wilmington. Sig- 

 nals were also exchanged between Macon and Montgom- 

 ery, Ala. Preliminary arrangements have been made 

 at Mobile for the next season's work, and the station 

 at New Orleans has been selected. The arrangements 

 for determining the difference of longitude between New 

 Orleans and the observatories along the eastern coast 

 of the United States are therefore fast approaching 

 their completion. 



