59 



I only spent the night in observing at Prairie du Chien, and was 

 obliged to leave that place early the next morning, on my return to 

 Chicago. Hence I had no opportunity for making any survey to 

 connect our two stations, and thus determine accurately their relative 

 positions. In looking up the Mississippi, however, from my station, 

 I observed that its course upward appeared, when compared with the 

 direction of the North Star (Polaris) to be a very little west of north. 

 The difference of our longitudes, reduced to a common point, is not 

 probably more than one second of time; and, judging by the eye, of 

 the distance from my station to the Fur Company's old house, our 

 latitudes appear to agree very closely. 



XI. DUNLEITH, ILLINOIS. 



Station. — One hundred feet east from the left shi;reof tlie Mississippi 

 river, between the freight depot and the passenger house of the North- 

 western terminus of the Illinois Central Rail Road. From the ob- 

 serving station to a point perpendicularly under the most northern of 

 the two cupolas on the north end of the ticket office, of this rail road 

 depot, is S. 13° W. 250 feet, horizontal measurement. 



Ist. The Latitude. 1859, Febrvary 22d. 



By .37 circum-meridian altitudes of /3 Orionis, south, 

 combined with 24 altitudes of Polaris (oc Ursse ^ 

 Minoris,) north, - - - - 42 29 45.16 



Same night. — By 26 circum-meridian althudes of a, 

 Hydrce, south, combined with 14 other altitudes 

 of Polaris, observed 5 hours later than the pre- 

 vious set, - - - - - 42 29 44.65 



/2e5t//«— Latitude of station, - - 42 29 44.9 N. 



2d. Observations for the Time. 1859, February 2\st. 



Sidereal chronometer No. 2557, fast : 



1st Set. Before the telegraphic signals. 



By 10 observations on a Arietis, west h. m. s. 



(at Qh. 16m.) - - 1 38 14.48 



By 1 1 observations on y' Leonis, east 



(at U. 39m.) - - 1 38 14.67 



