ADJUSTMENT BY LEAST SQUARES yey 
quently transformed into decimal fractions of a dyne. The excesses 
varied in sign and size, many exceeding 100 units and the largest being 
346. Many of the actual link-increments exceeded 1,000 units, and 
as these depend on measured gravity-gradients of which the accuracy 
rarely exceeds 2 to 3 per cent in practice, it is considered meticulous 
to obtain the adjusted values of the link-increments to nearer than 
ro units. The procedure thus resolves itself into one of obtaining from 
the excesses the corresponding correlates to the nearest 1o units. 


TABLE VIII 
A d’ *m div 
I 8) —14 = 5 
2 5 — 34 I 
3 3 — 46 ch 
4 ens) —46 2 
5 SAIN aaa TOKO =f 
6 18) — 143 a3 
al — 290 — 205 =i 
8 130 == 9/7) —4 
9 180 35 4 
10 45 40 2 
To facilitate setting down the related first- and second-remove cor- 
relates corresponding to each key correlate, it is convenient to replace 
every triangle in Figure 7 by a correspondingly numbered dot, situated 
roughly at its center of position, and to join these dots by lines repre- 
senting contacts of adjacent triangles. A triangle is thus represented 
by a point from which radiates a number (one, two or three) of lines 
to each of its first-remove points, from which again outwards radiate 
lines to the second-remove points. Commencing at any one point it 
is easy for the eye to pick up the first- and second-remove points in 
turn. These are tabulated on the working sheets, of which Table IX 
shows a typical example used for the first five points in order. The 
first column, headed JN, is used for the common divisors obtained 
from formulae (9g) and (10) by simply subtracting the number of 
first-remove points from 9 in each case, since in this network n=3 
and n?=o throughout. 
The second column marked A contains the key-point number, fol- 
lowed after an interval of one line by the numbers of its first-remove 
points in order. The third column, marked + m’—, is used for com- 
puting m’ from the excesses given in Table VIII and equation (9). The 
excess for the key point is multiplied by 3 and set down opposite 
that point; the excess for each first-remove point is set down directly; 
the + and — columns are totalled and the aggregate sum divided by 
837 
