APPENDIX I. 275 



their longitudes being from the preceding determina- 

 tion 27 3 o. the diredt diftance between the places 

 meafured on a great circle of the earth will appear by 

 trigonometry to be 16° 57'. or about 1773 verfts rec- 

 koning 104^ verfts to a degree. This diftance confifts 

 partly of fea, and partly of land ; and a conftant inter- 

 courfe is kept up between the two places, by means of 

 Ochotsk, which lies between them. The diftance by fea 

 from Bolcheresk to Ochotsk is eftimated by fliips reckon- 

 ings to be 1254 verfts, and the diftance by land from 

 Ochotsk to Yakutsk is 927 verfts, making altogether 

 2181. The direct diftance deduced by trigonometry, 

 (on a fuppofition that the difference of longitude between 

 Bolcheresk and Yakutsk is 27° 3'.) is 1773, falling 

 fliort of 21 8 1 by 408. a difference naturally to be ex- 

 pe<Sted from conlidering, that neither roads by land, or 

 the courfe of fliips at fea, are ever performed precifely 

 on a great circle of the earth, which is the fhorteft line 

 that can be drawn on the earth's furface between two 

 places. 



By this agreement between the diftance thus eftimated, 

 and that deduced by computation, on fuppofing the dif- 

 ference of longitude between Yakutfk and Bolcherefk to 

 be 27° 3 . it feems very improbable, that there fliould 

 be an error of many degrees in the aftronomical deter- 

 mination. 



N n 2 Since 



