ASTRONOMY. 51 



Now, it was observed ( 58. d.) that the degree in 

 lat. 45 is an arithmetical mean between any two 

 degrees equally distant from it no the north and 

 south ; and therefore if an arch of any number of 

 degrees, for example 6, be measured on the south 

 of 4-5, and an arch of as many degrees on the 

 north, the two together will be 12 times the degree 

 in the parallel of 45. If, therefore, the above ex- 

 tent, 722264.79, be divided by 12.6689, the ampli- 

 tude of the arch, the quotient 5701 It is the.degree 

 of the meridian bisected by the parallel of 45. 



f. The degree at the Equator is deduced from an arch 

 of 3 7' measured in Peru by the French and Spa- 

 nish academicians. Jt is stated by BOUGUER at 

 56753*; by CONDAMINE, at 56749 ; and we pre- 

 fer the latter number, as there is reason to think, 

 from comparing that degree with others, that it 

 is too great. Figure dc la Tcrre, par M. BOUGUER, 

 Sect. v. p. 272. 



g. The degree lat. H, is a mean of 6 degrees, mea- 

 sured by Major LAMBTON in Indostan. Asiatic 

 Researches, vol. xn. p. 94. 



h. The degree in lat. 52 2' 20" is from an arch of 

 the meridian measured by Colonel MUDGE in the 

 south of England. The mean is given here from 



a paper, Phil. Trans, for 1812, p. 332. 

 r t f 



i. The degree at the Polar Circle, or in lat. 66 20' 10", 

 is from an arch of the meridian lately measured by 

 SWANBERG and other Swedish academicians. Ex- 

 position 



