STATIONS NEAR THE NORTHERN BOUNDARY OF OHIO. 243 



points in the United States, north of the Ohio river : the longitudes of 

 the maps of these northern states having hitherto been made to depend 

 on the observations of Ellicott and De Ferrer, at points on the Ohio 

 river, and on meridian lines traced from this river several hundred 

 miles northward by the deputy-surveyors. When we consider the 

 uncertainty of such operations, from the irregularity of local variations 

 of the compass, it will appear somewhat remarkable that the maps of 

 those states should have been so correct as they are shown to be from 

 the result of Captain Talcott's observations. Thus we find for the po- 

 sition of Turtle Island, Lake Erie, 



h. 771. S. 



By Tanner's map U. S., 1837, Turtle Island west of 

 Capitol, --------- 



Deduct for error of Lambert's longitude of Capitol, used 

 in this map, -------- 



By the same map, corrected for Lambert's error, 



By Capt. Talcott's moon-culminations, Turtle Island, W. 

 of Greenwich, -------- 



Deduct longitude of the Capitol (Section XI., note). 



By Capt. Talcott's moon-culminations, T. Island west of 

 Capitol, --------- 



By Tanner's map. Turtle Island too far east, 



A similar comparison for South Bend, Lake Michigan, 

 gives. 



South Bend, by Tanner's map, west of Capitol, - - 41 15'2 



Deduct Lambert's error, - - _ - . 25-0 



Result by map, -- 40 50-2 



Result by moon-culminations, - - - - -41 11 -6 



By Tanner's map, South Bend too far east, - - 21-4 



SECTION II. 



The full advantages afforded by moon-culminations, for perfecting 

 geography, were first pointed out by Mr Nicolai, director of the Man- 

 heim observatory, in 1821, in a paper which appeared in the first num- 

 ber of Schumacher's celebrated Astronomische Nachrichten. The 

 same subject was shortly after proposed to the Astronomical Society of 

 Ti.— 3 L 





25 



44-2 

 25-0 





25 



19-2 



5 



33 



31-8 



5 



8 



7-0 





25 



24-8 

 5-6 



