the mean Derijity of the Earth. ' 747 
angles. The bafe and fedtion lines in each figure. are alfo 
drawn nearly in the fame direction as they are in the 
plan or on the ground, fuppoflng the top of the paper to 
be the North, towards which a perfon looks when vie ve- 
in? the ground from the South. 
Having finifhed the computation of the relative alti- 
tudes of all the points, the next confideration is how they 
are to be applied in determining the attraction of the 
hill. In whatever manner this laft mentioned operation 
may be performed, it is evident, that all the points and 
feeftions with their altitudes muft be entered in the plan. 
Wherefore, having accurately contracted a large plan of 
the ground, as before mentioned, containing all the prin- 
cipal lines or bafes, at the extremities of which either ver- 
tical or horizontal angles were taken, from them I then de- 
termined in this plan the places of all the other points in 
the lections, whether vertical, horizontal, or irregular. 
Thefe places or points were determined by drawing lines 
from each extremity of the bafe fo as to form with it 
angles equal to thofe which were obferved on the ground 
for each correfponding pole; the interactions of thefe lines 
are the places of the poles, which having marked with a 
fine dot or point of ink, and written clofe to each point 
the proper number expreffing its relative altitude, and 
cleaned the paper by rubbing out the lines forming the 
1 4 Z 2 angles 
