, Astronomical and Meteorological Records^ ^c. xxxi 



Equal altitudes of Sun to find error of Time-piece, (box chrono- 

 meter, J at noon. 



Sept. 14,1820. 

 Sept. 15, 1820. 



Time fi'om Noon, 

 A. M. 



Error of Time- 

 piece. 



3h 14' 23" 

 3 12 49 

 3 11 16 



7' 08" slow. 

 Mean time. 



»3 mean of seven lunar observations, distance of nearest limbs of sun 

 and moon — taken at the moutJi of the Missouri. 



Sept. 15, 1820. 



Time of observa- 

 tion, P. M. 



4*' 20' 25" 

 Baromet. 29.02 



Distance of Sun 

 and Moon. 



93° 57' 08" 

 Thermomet. 72° 



Index error. 



-f 27' 



Allowance to be made for error and rate of time-piece, as usual. 

 Longitude deduced, 5'' 59' 48", or 89° 57' W. of Greenwich. 



The longitude of the mouth of the Missouri as above is 89° 57' W. 

 of Greenwich; and the longitude of St. Louis deduced from a set of 

 lunar observations on the 16th of June, 1819, (see page 10,) is 90° 06' 

 15" W. of the same meridian. The observations at both places were 

 made with the same instruments, and under equally favourable cir- 

 cumstances, they are accordingly entitled to the same weight as re- 

 spects accuracy. But by a traverse of the river between the two places, 

 a distance of 18 miles, the mouth of the Missouri is found to be only 

 1' 55" of longitude E. of St. Louis. Now by taking a mean between 

 the two results deduced from observations, and in one case adding, 

 and in the other subtracting 57^ = half the difference of longitude by 

 the traverse, the following results will be obtained, entitled to double 

 the confidence of the result of either of the lunar observations above 

 mentioned individually considered, viz : 



Longitude of St. Louis, agreeably to this estimatel 90° 02' 35" W. 

 *Do. of mouth of the Missouri - I 90 00 40 W. 



Observations made at the confluence of the De Moijen and Mississippi 



rivers. 



Aug. 8, 1820. 



Meridian double altitude of 

 star Altair, («. Aquil«) 



Inde^ error -\- 22". Latitude 

 deduced 



116° 05' 45" 



40 21 43 N. 



* Remarkable that the mouth of this greatest tributary in the world is just 

 one-fourth the circumference of the earth in degrees, west of the great Green- 

 wich observatory. 



