65 



We regret that we had not time to make a connection, by survey, 

 from our astronomical station at Dunleith, to the stone monument on 

 the east bank of the Mississippi river, erected to mark the western 

 terminus of this boundary line. From a close reconnoissance, how- 

 ever, we infer that the latitude of this monument is about 42"^ 30' 20", 

 and hence, that the monument is placed about one-third of a mile too 

 far to the north. 



XII. DUBUQUE, IOWA. 



This city is situated on the west bank of the Mississippi river, op- 

 posite to Dunleith, Illinois. 



From a reconnoissance and bearings observed from several points 

 in Dunleith, based on the latitude and longitudeof our Dunleith station, 

 as already given, we are enabled to give the approximate position of 

 Dubuque as follows. The distance between the two points being, in 

 a direct line, not more than one and one-fourth mile, viz. — 



Centre of the city of Dubuque. 



Latitude, .... 42^ 29' 55" N. 



Longitude, west of the meridian of Greenwich, Gh. 02?n. 405. 



Equal, in arc, to ... 90° 40' 00" 



XIII. FULTON, ILLINOIS. 



This city is situated on the east shore of the Mississippi river, 136 

 miles west of Chicago, b}' the track of the Chicago, Dixon, and Iowa 

 Air Line Rail Road, of which it is, at present, the western terminus. 

 Immediately opposite is the city of Lyons, situated on the west shore 

 of the Mississippi. Observations were made at both places, and the 

 observing stations were connected by a triangulation and azimuths, 

 derived from an observation on Polaris (at Ursse Minoris). From the 

 astronomidal station at Fulton, to that at Lyons, is 3595.5 feet, on an 

 azimuihal course of N. 08° 43' W. Hence the Lyons station is 

 -f 12". 89 north of the parallel and -f 44". 29 in arc, = + 2s.95 in 

 time, west of the meridian of the Fulton Station. We shall have oc- 

 casion to use this difference of latitude in a])plying a common correc- 

 tion ( — 1 ".92 in the one case, and + 1".92 in the other), to the observed 

 latitudes of these two stations, in order to render the difference of their 

 latitudes consistent with the result of the survey. The survey gave 

 us, also, the longitude of the Lyon's Station, based on that of the 



VOL. VII. — I 



