43 



21th, {Omitted in the proper order of dates.) 1858, March 2'2d, 

 At Chicago Observing Station, No. I, in lat. 41° 53' 50". 3 

 N.: long. 5h. 50m. 30.995. ivest of the meridian of Greenwich. 

 See page 351 of Vol, VI. of the Society's Proceedings. 



Mean solar chronometer No. 141, slow of mean time, at apparent 



noon: 

 By 5 pairs of equal altitudes of the sun's upper and m. s. 



lower limbs - - - - - — 4 56.26 



By comparison. — Sidereal chronometer No. 2557, 



fast of sidereal time for this station, at apparent 



noon, (say at Oh. 06m. 44s. sidereal time) - + 49 55.67 



I desired to get observations on East and West Stars for the time 

 on the night of iMarch 22d ; but ihe sky was entirely clouded, which 

 prevented it. On the next morning (March 23) I started with both 

 chronometers, the sextant and artificial horizon, on a journey to 

 Fulton and Albany, Illinois. I also visited Lyons, in Iowa. Having 

 observed for the latitude and longitude of these places — depending for 

 the longitude on the run of the two chronometers — I returned to 

 Chicago on the evening of March 29th, 1858, and made the following 

 observations for the time, viz : — 



2Sth. 1858, March 29th. At Chicago Observing Station Ao. I. 



Sidereal chronometer No. 2557, fast: 



By 7 observations on « Tauri, west (at m. s. 



8h. 48m.) - - - - 50 26.94 



By 11 observations on jS Tauri, also west 



(at 9/t. 21m.) - - - 50 27.14 



By 18 observations on 2 West Stars (at 

 9A. 08m.) giving weight according to 



the number of observations on each - 50 27.06 m. s. 



h 50 27.06 



By 20 observations on <* Bootis, east (at 



lOh. 20m.) . - - . -f 50 26.90 



liesvlt — Chronometer No. 2557, fast of sidereal time 



for this station (at 9^. 44m.) sidereal time + 50 26.98 



