Trigonometrical Survey. 489 
base of departure on Hounslow Heath, with that of verifica- 
tion on Salisbury Plain, and is bounded by the sides connect- 
ing the stations, Hanger Hill, St. Ann's Hill, Bagshot Heath, 
Highclere, Beacon Hill, and Four Mile-stone on the north, 
and on the south side by Four Mile-stone, Dean Hill, Butser 
Hill, Hind Head, Leith Hill, and Banstead. 
The second branch, is that which proceeds from the side 
Hind Head and Leith Hill, to the coast of Sussex and the Isle 
of Wight, and principally affords the sides which will be here- 
after used in finding the distance between Beachy Head and, 
Dunnose. This branch also proceeds westward for the sur- 
vey of the coast, and is bounded by the sides connecting the 
stations Leith Hill, Hind Head, Butser Hill, Dean Hill, and 
Wingreen on the north, and on the south by those connect- 
ing the stations Nine Barrow Down, Motteston Down, Dun- 
nose, Rook's Hill, Chanctonbury Ring, and Ditchling Beacon. 
The third branch, is that which proceeds from the side 
Hanger Hill and Banstead, to Botley Hill and Leith Hill, and 
from thence towards Beachy Head and Brightling, joining the 
series formerly projected at Botley Hill and Fairlight Down; 
the branch being bounded to the westward by the sides con- 
necting the stations Hanger Hill, Banstead, Leith Hill, Ditch- 
ling Beacon, and Beachy Head. 
The fourth branch, or remaining class of triangles, is that 
by which the distance between Beachy Head and Dunnose is 
obtained, and is formed by the sides connecting the stations 
Beachy Head, Ditchling Beacon, Chanctonbury Ring, Rook's 
Hill, and Dunnose. 
