Trigonometrical Survey. 



591 



each triangle, yet, for the reasons assigned in the preface, I have 

 chosen to depart from it on the present occasion. In another 

 principal triangle, the angle at Brown Willy is also supplementary : 

 it has already* been mentioned, that an instrument cannot be got on 

 the top of it. As to the angles at Kit Hill, in the two last triangles, 

 being inferred ones, it may be proper to mention, that Black Down 

 was chosen for a station, after the observations were made at the 

 former. To have visited Kit Hill a second time would have been 

 unnecessary, because there are not any distances, except to interior 

 objects, which depend upon those triangles. 



art. xii. Calculation of the Sides of a Set of principal Triangles, 

 carried on from the Side which joins the Stations on Beacon Hill, 

 near Amesbury, and Wingreen Hill, near Shaftsbury, towards the 

 Base of Verification on King's Sedgemoor. Plate XXIX. 



Distance from Beacon Hill to Wingreen Hill, 114522,4. Feet. Phil. Trans. 1795. p. 501. 



No. of 



trianiles 



IX. 



Names of stations. 



Wingreen Hill 

 Beacon Hill 

 Bradley Knoll 



Observed 



angles. 



8 9 57 37>75 

 32 11 43,25 



57 5° 3^25 



179 59 59,25 



Diff. 



—0,97 

 —0,48 

 —0,4.8 



Spheri- 

 cal 



*>93 



Error. 



-2,68 



Angles corrected 

 for calculation. 



89 57 37 

 32 "43 



57 5° 40 



Distances. 



Feet. 



72074 



l 3S 2 7 2 >3 



Bradley Knoll 

 Wingreen 

 Bull Barrow 



4° 43 5 2 

 96 20 37 



42 55 3 Z >75 



— 0,26 

 — 0,65 

 —0,25 







80 1,75 





1,16 



+0,55 



40 43 51,5 

 96 20 36,25 

 42 55 32^5 



Bull Barrow fromf^ dle y Kn ° 11 

 L Wingreen 



105180 

 69053,6 



In the Philosophical Transactions for 1797, p. 455, the distance from Bull Barrow to 

 Wingreen is said to be 69058, being \\ feet greater than the above conclusion. 



4 G 2 



