xxviii Astronomical and Meteorological Records, t?c. 



Observations made at the mouth of the river Platte. 



Feb. 29, 1820. Meridian double altitude of 

 stiar Sirius, {a. Canis majoris) 



March 1, 1820. 



March 2, 1820. 



March 3, 1820. 



Index error- 

 deduced 



4' 10". Latitude 



Meridian double altitude of \ 

 sun's upper limb - ' 



Index error — 4' 10". Latitude 

 deduced 



jSIeridian double altitude of 

 sun's lower limb 



Index error — 4' 00". Latitude ^ 

 deduced - " 5 



65° 03' 45" 



41 03 UN. 



83 44 30 



41 03 18 N. 



83 25 20 



41 03 16 N. 



Meridian double altitude of 

 sun's lower limb 



Index error — 4' 00". Latitude 

 deduced 



84 11 45 



41 03 07 N. 



41 03 13 N. 



Latitude of the mouth of river Platte by a 

 mean of the preceding results 



The foregoing observations were made with the sextant of 5 inches 

 radius, and at the most northern point of the junction of the river 

 Platte with the Missouri. The difference of latitude of the two shores 

 is about one minute. For further remarks and observations at this 

 place, see the Meteorological Register for the montji of March. 



M the mouth of Elk-horn river tributary to the Platte, the following 

 observation ivas made for the latitude. 



March 7, 1820. 



Meridian double altitude of 

 sun's lower limb 



Index error — 4' 15". Latitude 

 deduced 



87° 00' 00" 



41 12 00 N. 



On the 12th of April, trigonometrical observations were made in 

 conjunction with Lieut. Andrew Talcott of the corps of Engineers, to 

 ascertain the height of the bluffs near the pond on the Boyer river, 

 1| miles above its junction with the Missouri. From these observa- 

 tions, which were made with the utmost care and precision, it appears 

 that the elevation of the bluff above the surface of the pond is 335.29 

 feet. The bluff of which tlic height is found as above, is visible on the 

 opposite side of the river from Engineer Cantonment, and is supposed 



