628 The Account of a 



first being 91 2' 45",75, and the last 88° 57' 15"; which angles, 

 however, are augmented by the addition of the differences be- 

 tween the horizontal angles and those formed by the chords,. 

 We have therefore, 



rBCF = 9 i° 2' 45,75" 

 In the triangle BCF \ BFC = 88 25 51,5 



[FBC= o 31 22,75 



fEAD = 88 57 17 

 And in the triangle AED I AED = 90 31 21,5 



IaDE= o 31 21,5 



And, using BC and AD, as found above, we get 



CF = 2859,1 ) feet 

 And EA = 2859,8] Ieet - 



Therefore FD = DC + CF = 22146,9 -j- 2859,1 = 25006 

 feet. And BE = BA = EA = 27864,5 — 2859,8 = 25004,7 

 feet. The mean, 25005,3 feet, may be considered as very nearly 

 the true distance between the parallels of Black Down and 

 Dunnose. This method is the same as that made use of in the 

 Phil. Trans, for 1795, p. 521, and affords the means of very 

 accurately determining the distance between the parallels of 

 latitude of the two stations, when the angles were observed with 

 precision, and the direction in which the stations lie, is not 

 much removed from east and west. 



This small space, 25004,7 feet, corresponds to 4' 6",s, in 

 which I use 60851 fathoms for the length of a degree of the 

 meridian in 50 41'. See Phil. Trans, for 1795, p. ^S7- 



Now the latitude of Dunnose is 50 37' 7",3, and its longitude 

 i° 1 1' 36" ; ( Phil. Trans, for 1 ygg, p. 536 ; ) therefore, 50 37 '7"g 



+ 4' ®*>5 == 5°° 4 1 ' 1 3"'^> ls tne latitude of Black Down. 



This method of finding the latitude seems to be more correct 

 than by spherical computation; yet, by this latter, nearly the 



