357 



6th. July 5tk, At Chicago Observing Station No. 3. 



Sidereal chronometer No. 2557, fast: 



By 14 observations on u Coronoe Borealis, W. (at h. m. s. 



I9h. 28m.) - - - - - 1 00 50.08 



By 18 observations on ctAndromedoejE. (at 20A. 00m.) 1 00 49.97 



Result — Chronometer No. 2557, fast of sidereal time 



for this station (at 19^. 447/1.) - - + 1 00 50.02 



By comparison — Chronometer No. 141, slow of mean 



solar time for this station (at 12/t. 48m. mean time) — 4 49.88 



1th. 1858, July 7th. At Chicago Observing Station No. 2. 



Sidereal chronometer No. 2557, fast: 



By 5 observations on u, Lyree, E. (at 15^. 27m.) 



using horizon roof No. 1, beins: h. m. s. 



an old one in use 18 years, - 1 01 00.06 



By 8 observations on a Bootis, W. (at 



16A. 17m.) with same roof, - 1 00 59.34 



By E. and W. stars (at 15^. 52m.) 



using horizon roof No. 1, + 1 00 59.7 h. m. s. 



1- 1 00 59.70 



By 5 observations on u, IjJX^, E. (at 



15A. 36m.) using horizon roof No. 



2, a new one, - - - 1 00 59.91 



By 7 observations on a Bootis, W. (at 



16^. 02m.) also using roof No. 2, 1 00 59.41 

 By the same E. and W. stars (at 157t. 



49m.), using horizon roof No. 2, + 1 00 59.66 



\- 1 00 59.66 



Result — Chronometer No. 2557,fastof sidereal time 

 for this station (at 15/i. 507/1.) by 10 observations 

 on 06 Lyra3, E.; 15 observations on ex, Bootis, W. + 1 00 59.68 



By comparison — Chronometer No. 141 , slow of mean 



solar time for this station (at 8A. 48m. mean time) — 4 48.79 



