THERMOMETRICAL OBSERVATIONS. 249 



Latitude by s Bootis . 3 1 o 43 

 do. . a Coro. Borealis 31 o 40 7 

 do. . a Lyr^ . 310 34.7 



Mean Latitude North . 31 o 39.5 



The difference of the refults given by the two inftruments appears to be 

 l''.6 ; but the radius of the large feiSor, being mure than three times that 

 of the fmall one, it may fairly be confidered at leaft three times as accu- 

 rate; and as double the number of ftars were taken witli the large one, it 

 is on that account entitled to double the accuracy : — hence if to five times 

 the latitude given by the large feftor, the latitude given by the fmall one 

 be added, and the fum divided by fix, tlie quotient 30° o' 38''.! will be 

 the latitude in which each inftrument has its due weight ; from which it 

 follows, that the obfervatory was too far north by 38".!, or 3S53.8 feet ; 

 but the end of the guide line was 3617.8 feet fouth of the obfervatory, — 

 hence the end of tlie guide line was too far north by 236 feet, which was 

 carefully laid off to the fouth, and the guide line correfted back as in the 

 former cafes agreeably to Plate IX. From the termination of the meafure- 

 ment anotlier guide, or compafs line was caiTied on to the weft fide of the 

 Chatahocha, or Apalachicola river the diftance of 381 n'''ks, and 7 perches, 

 eaft of high water mark on the Milliilippi. 



At the termination of the compafs, or guide line on 

 the Chatahocha, or Apalachicola river, the following ob- 

 fervations were made. 



July 25th. Arrived at the end of the guide line, in a 



heavy fhower or rain. 

 26th. Cloudy with rain all day. 

 27th. Cleaned, and fet up the clock. — Cloudy 



witii rain. 

 28th. Cloudy with rain all day. — Thermometer 



82" in the morning, fell to 80" at 10 o'clock 



A. M. 

 29th. Thermometer 74" in the morning. Thick 



fog. Thermometer 84° in the afternoon. 



Put up both Sedors, with their Faces to the Eaft. 

 30th. Thermometer 74° in the m.orning, rofe to 87". 



Obferved 



