67 



Sd. The Longitude. 

 1. By the transmission of mean solar chronometer No. 141, from 

 Chicago to Fulton and back to Chicago, between the 22d and 29th of 

 March, 1858. Rate, during the elapsed time, — Os.744 per mean 

 solar day. 

 1858, March 24/t/i.— Chronometer No. 141, was fast m. s. 



of Fulton mean solar time at apparent noon, + 5 10.72 



1858, March 22d.~S\o\v of Chicago 



mean solar time at Chicago, appa- m, s. 



rent noon, - - - — 4 56.26 



Elapsed time, 2.007 mean solar days, 



allowing for diff. of longitude of 



stations, X — Os.744, = — 1.49 



Chronometer No. 141, slow of Chi- 

 cago mean time, at the period of 

 Fulton apparent noon, of March 

 24th, 1858, - - - — 4 57.75 



-— 4 57.75 



(a) Difference — Fulton, west of Chicago, - -f- 10 08.47 



2. By sidereal chronometer No. 2557 : 

 1858, March 2Uh. — Chronometer fast of Fulton si- 

 dereal time (at OA. 14m. sidereal time) -\- 1 00 13.75 

 1851, March 22d. — Fast of Chicago 



sidereal time (at Oh. 06m. 44s. h. m. s. 

 sidereal time) - - + 49 55.67 



Elapsed time, allowing for difT. in long. 

 = 2.012 sider.days, X + 4s.23, 

 the rate per sidereal day, = + 8.51 



Chronometer No. 2557, fast of Chi- 

 cago sidereal time, at the period of 

 the Fulton time observations, -}- 50 04.18 



+ 50 04.18 



(6) Difference. — Fulton west of Chicago, - - + 10 09.57 



If we take the time-observations at Fulton, of the 28th March, 1858, 



