61 



Result adopted — Chronometer No. 2557, fast of si- 

 dereal time for this station (at Sh. 46m.) Feb. h. m, s. 

 22d, 1859, - . - - + 1 38 20.23 



^d. The Longitude. 



We have two determinations of the longitude of our Dunleith station. 

 The first is derived from the time-observations made at that station, 

 and the signals interchanged with Chicago, on the night of Feb. 21st. 

 The second is derived from the similar observations and signals made 

 on the night of Feb. 22d. They both depend in part upon the run of 

 the mean solar chronometer No. 141, while at rest at Chicago as as- 

 certained by the time-observations made there on the nights of Feb. 

 20th and 23d, already given. 



The telegraphic signals, and the results, for the 1st determination, 

 are as follows, viz. — 



Determination of the diffei'ence of Longitude between Chicago and 

 Dunleith^ Illinois, by electric signals for comparisons of time, 

 February 2lst, 1859. 



Sidereal Chronometer No. 25.57, fast, of Dunleith, sidereal time, 

 (at 9A. 41m. sidereal time,) Ih. 38m. 14.90s. 



Rate per sidereal day, -f 5s.308; or per sidereal hour, + 0s.221. 



Mean Solar Chronometer No. 141, slow, of Chicago, mean solar 

 time, (at lO/i. 47m. mean time,) 4m. 42s.l4. 



Rate per mean solar day, — Os.746; or per mean solar hour, — 

 Os.03109. 



1st. — Chicago signals recorded at both stations. 



1st Mean. — Electric signals sent from Chicago to Dunleith, 



12 04.673 



