521 
Trigonometrical Survey. 
f W B D = 6 55 57,2 
In the triangle WBD WDB = 8i 56 52,4 
L D WB = 91 7 10,4 
rBDR = 8 3 6 
And in the triangle B D R 1 D B R = 83 4 1 
[DR B =88 52 53 
In which it must be noted, that the reduced angles are given 
to the nearest i".' 
Now the chord of the arc B D, or the distance between 
Beachy Head and Dunnose, is 33 9397,6 feet (vide Sect. iv. 
Art. viii.), which used in the 
Triangle WBD f BW — 336 1 15,6 feet 1 and the triangle f DR =z 336980 feet 
gives - \DW- 40973,4 feet J BDR - \BR r 47547,1 feet. 
Again ; let B L and D E be the parallels of latitude of 
Beachy Head and Dunnose, meeting the meridians in L and 
E : then, to find LW and E R we have two small triangles 
which may be considered as plane ones, namely, LBW and 
E D R, in which the angles at W and R are given, nearly. 
Now the excess of the three angles above i8o°in the triangle 
DBW, considered as a spherical one, is 3" nearly ; therefore 
the angle DWB will be 91 0 7' 12" nearly; hence BWL = 
88° 52' 48" : consequently the angle B LW = 90° 33' 36", and 
LBW= o° 33' 3 6". Therefore with the chord of the arc WB 
= 336115,6 feet, we get W L = 3285,2 feet, which added to 
WD, as found above, gives 44258,6 feet, for the distance be- 
tween the parallels of Beachy Head and Dunnose. 
Again ; in the triangle BDR, considered as a spherical 
one, the excess is about 3"^ ; hence, from the two observed 
angles at D and B, namely, 8° 3' 7", and 83° 4' 2", we get the 
third angle BRD = 88° 52' 54", 5; and taking the triangle 
ERD as a plane one, the other angles will be o° 33' 32", 75 
'EDR), and go 0 33' 32", 75 (DER) ; therefore, with the chord 
