82 



Island comity, [llinois — published in 1857, on a scale of 1 mile to 1 

 inch — to our Station XVII., we obtain the approximate positions of 

 several places in the vicinity, as follows, viz. — 



NAMES OF PLACES. 



1. Rock Island City, Illinois, - - 



2. Mouth of Rock River ; the west 

 extremity of the island in the 

 mouth of said river, - - - - 



3. Moline. The south end of the 

 bridge connecting with Rock Is- 

 land, --------- 



4. Watertown, ------ 



North Latitude. 



o / // 



41 28 14.3 



41 29 01. 



41 30 37 

 41 32 19.6 



Lougitude west from Greenwich. 

 In Arc. In Time. 



o / // 



90 35 06 



90 30 49 

 90 25 02 



h. m. s. 

 6 02 20.4 



90 35 53 16 02 23.5 



6 02 03.3 

 6 01 40.1 



XVIII. FORT ARMSTRONG, ILLINOIS. 



This old fort is situated on the point at the west or lowest extremity 

 of Rock Island; an island in the Mississippi river, between the "City 

 of Rock Island" and the City of Davenport. 



By Hogane & Lambach's map of the City of Davenport, published 

 in 1857, on a scale of 9 inches to 1 mile, or 5S6f feet to the inch ; 

 and on C. H. Stoddard's map of the cities of Rock Island, in Illinois, 

 and Davenport in Iowa, published in 1851, on a scale of 13.2 inches 

 to 1 mile, or 400 feet to the inch, — scales which admit of minute 

 measurements of courses and distances, — Fort Armstrong is laid down 

 in reference to the centre of Washington Square, in the City of Rock 

 Island, our astronomical station, XVII., as follows, respectively, viz. — 



