748 Afr. hutton’s Calculations to afcert.ain 
angles by which the points w'ere determined, there re- 
mained only the points with the figures exprefling their 
altitudes diftinctly exhibited in the plan (fee tab, ix.) 
It remains now to apply all the foregoing calculations 
and contractions to the determination of the effect of 
the attraction in the diretion of the meridian. And 
here it foon occurred, that the belt method was to divide 
the plan into a great number of fmall parts, which may 
be confidered as the bafes of as many vertical columns or 
pillars of matter into which the hill and the adjacent 
ground may be fuppofed to be divided by vertical planes, 
forming an imaginary group of vertical columns, fome- 
thing like a fet of bafaltine pillars, or like the cells in a 
piece of honey-comb; then to compute the attraction of 
each pillar feparately in the direction of the meridian ; 
and laftly, to take the fum of all thefe computed effects 
for the whole attraction of the matter in the hill, &c. 
Now the attraction of any one of thefe pillars on a body 
in a given place may be eafily determined, and that in 
any direction, to a fufficient degree of accuracy, becaufe 
of the fmallnefs and given pofition of the bafe ; for, on 
account of its fmallnefs, all the matter in the pillar may 
be fuppofed to be collected into its axis or vertical line 
erected on the middle of the bafe, the length of which 
axis, as the mean altitude of the pillar, is to be eftimated 
from 
