119 [237 J 



in ihe Great Eastern Bend, about six miles above Engineer Cantonment^ 

 and three below Council Bluffs, by water. According to Lieutenant Fre- 

 mont's reconnoissance, the island is two or three miles west of the meridiaa 

 of Engineer Cantonment. 



The daily rate of the chronometer, ascertained as well as could be, in 

 two successive nights, and proving very nearly the same as at St. Louis, 

 we have for the longitude of the island, as inferred from St. Louis, 95*^ 

 45' 30". 



When we consider the respective positions of the island, and of Engi- 

 neer Cantonment, the longitudes of the two places accord sufficiently to 

 induce the belief that the error which may still affect ihem is so small as to 

 be of very little consequence in geographical purposes. 



XV. FORT CHARLOTTE — OLD AMERICAN TRAniNG-HOUSE — NORTHWEST 

 company's coast of lake superior, at THE WEST END OF THE 

 GRAND PORTAGE. 



My friend Mr. James Ferguson, the astronomer of the American com- 

 mission for determining the northern boundaries, and now one of the princi- 

 pal assistants in the coast survey under the superintendence of Mr. Hassler, 

 who has furnished me with valuable information in regard to this section 

 of country, has observed at this place the solar eclipse of the 26ih of June, 

 1824. He has communicated to ine the data and conclusions of his obser- 

 vation, which was with a telescope of 2^ feet focal length, having a mag- 

 nifying power of about 60 times. The data are as follows : 



June 26, 1824. Beginning of the eclipse at 6/i. 7m. Is., p. m. mean time. 

 End - - - 7 13 19.2 do. do. 



The result of the calculation, without referring to corresponding obser- 

 vations, or correcting for the errors of the tables, gives for the longitude 

 89° 59' 31". 



XVI. FORT WILLIAM, AT THE ENTRANCE OF KAMINISTiaUIA RIVER, NORTH- 



WEST COAST OF LAKE SUPERIOR. 



Longitude from Sir J. Franklin's second expedition, ap- 

 pendix Table I - - - - - - 89° 16' 30" 



From the commission for settling the boundary, appendix 



cxxx - - - - - - - 89 22 40 



From the solar eclipse at Fort unarlotte by Mr. Ferguson • 89 20 18 



Mean longitude in arc - - - 89 19 49.3 



From Sir J, Franklin's second expedition, nbi supra • 48° 23' 40" 



By Mr. Ferguson, mean of 35 sets of observations - 48 23 11 



Mr. J. E. Colhoun — Major Long's expedition - - 48 23 33 



Mean latitude - - - - 48 23 28 



XVII. DELTA OF THE MISSISSIPPI RIVER. 



An important work, ordered by Congress, in relation to the improve- 

 ment of the navigation of the mouth of the Mississippi, was executed in 

 1838 and 1839, under the direction of Captain A. Talcott. A triangula- 



