36
CALCULATIONS TO ASCERTAIN THE TRACT 2G.
siction 71, from S' to k.
section 72, from V to n-
Pule
Slope
Vert. /. >s
Horiz.
Diff.of
Pole
Slope
Vert. Z's
Horiz.
Diflf. of
Dist.
at S'.
Dist.
Alt.
Dist.
at
Dist.
Alt.
1
727
1°3 39‘o
706
167
1
528
§"To e
527
38
o
1455
9 441
1434
242
2
H 88
4 10
1185
95
3
1720
9 4|
1699
267
3
1594
6 S
1585
179
4
1984
7 52
1965
267
Ends
5
2547Endsat k.
7 3
2528
308
at N.
Besides these sections, there were many more single points,whose places and relative altitudes were observed, and com-puted ; but it is not necessary to abstract them all here.
The following plate, N°. 1, has 72 figures, answering tothese 72 sections, each to each, according to the numbers.In these figures, the line having the letters/), p,p, &c, an-nexed, is the section line, the letters p, p , &c, denoting thepoles; the other line, forming the angle with the section, isthe base line; and between them are the degrees and minutescontained in the angle formed by them; at the angular pointwas observed the elevation or depression of each point p; andthe bearings or horizontal anodes were observed at the otherend of the base, whence faint lines are drawn to some of thepoints p, forming with the base line those horizontal angles.The base and section lines, in each figure, are also drawnnearly in the same direction as they are in the plan, or onthe ground, supposing the top of the paper to represent theNorth, towards which a person looks when viewing theground from the South.
Having finished the computation of the relative altitudesof all the points, in the sections, the next consideration is, howthey are to be applied in determining the attraction of the hill.In whatever manner this last mentioned operation may be per-formed, it is evident, that all the points and sections, with theiraltitudes, must be entered in the plan. Therefore, havingaccurately constructed a large plan of the ground, as beforementioned, containing all the principal lines or bases, at theextremities of w'hich either vertical or horizontal angles were