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each pole, and likewife the horizontal angle contained 
between the plane of the fe6tion poles and the next fta- 
tion pole to the right or left. The theodolite was then 
removed, and planted diredfly over the centre of this 
nation pole, which was removed for this pnrpofe ; and 
the horizontal angle taken between a pole now planted 
at the firft ftation and each of the poles of the fecSlion. 
The horizontal diftance of the two ftation poles being 
known, the horizontal diftance of each of the fe6lion 
poles from the firft ftation, and their refpedlive perpen- 
dicular altitudes above it, or depth below it, will be given. 
It is manifeft, that thefe operations, when conne61ed 
by angles with the two ftations of the obfervatory and 
the meridian line, would at the fame time give the fliape 
and dimenlions of the hill, and the diftance of the pa- 
rallels of latitude pafling through the two ftations of the 
obfervatory, as well as their refpecftive elevations above 
the bafe of the hill. But errors being apt to accumu- 
late in a long chain of triangles ; to obviate this danger, 
as well as to produce a check on any great miftakes, that 
might happen to be made in reading off, or writing down, 
the angles, I caufed a heap of ftones, or carit as it is 
called by the people of the country, to be raifed in a cir- 
cular figure fix feet high, at the higheft pomtof the ridge 
of the hill, which is to the Weft of it, as a fignal to be 
obferved from the feveral angles of the polygon, and as 
a means of connecting the two ftations of the obferva- 
tory by a fmaller number of triangles. Another earn 
towards the Eaftern end of the ridge of the hill was 
Y y y 2 afterwards 
