Trigonometrical Survey. £09 
So near an agreement in a length of almost 99 miles, can 
only be attributed to chance. 
Hence it appears, that a difference of 5 or 6 feet in about 27 
miles (the distance of the stations Hollingbourn Hill and Fair- 
light Down), may be supposed in General Roy's deductions 
on account of the variations, or corrections in the bases on 
Hounslow Heath, and Romney Marsh ; this difference, how- 
ever, is too trifling to be of consequence in any of his principal 
conclusions. 
art. viii. branch iv. Consisting of the nearest Triangles to 
the northward of Beachy Head and Dunnose, /or finding the 
Distance between those Stations. 
No. of 
triangles. 
Names of stations. 
Observed 
angles. 
DifF. 
Spheri- 
cal 
excess. 
Error. 
Angles corrected 
for calculation. 
JCXXVIII. 
Dunnose 
Rook’s Hill 
Chanctonbury Ring 
‘5 43 0 
137 16 48,5 
27 0 13 
+ °>55 
-3,88 
+ i >37 
" 
u 
15 43 0,5 
*37 *6 44 »S 
27 0 15 
0 
0 
1.96 
— 0,46 
By this triangle, using the distance from Rook's Hill to 
Chanctonbury Ring as found by the first branch, we get the 
distance between Rook's Hill and Dunnose, 143559,3 feet ; but 
by the same branch, 143558,9 feet was found to be the distance ; 
and if the side Butser Hill and Dean Hill be made the base, 
we shall get, by the 22d and 23d triangles, the distance from 
Rook's Hill to Dunnose 143557,1 feet : hence 143558,4, the 
mean of these three distances with the above triangle, give 
214498,4 feet, for the distance between Dunnose and Chanc- 
tonbury Ring. 
MDCCXCV. 3U 
