Y> between the meridians passing through University Pillar and
Waterval, respectively. By virtue of the line terminals' relative
positions west of the central meridian
Y ATN BTN
{GINi e){GIN2 e)
GIN1 GIN 2
i'39"-2
where ATN and BTN are the meridianal directions through
University Pillar and Waterval, respectively
GIN1 and GIN2 are the directions of gyro-indicated north
through University Pillar and Waterval, respectively
s is the calibration constant of the gyro-theodolite concerned,
i.e. GIN 1 ATN GIN2 BTN.
The criterion by which the performance of the instrument is
judged is then simply the residual, v, given by
v y GINi GIN2.
Alternatively, in terms of angles the residual, v, may be expressed as
v y (a p) 1800
where a the anti-clockwise angle G/Ah-University Pillar-Water
val
(3 the clockwise angle G/AYWaterval-University Pillar
The above relationships are illustrated in Figure 3 below.
Figure 3
277
TN
GIN 2
TN
Waterval
GIN 1
BA
BA
AB
KAB
University
D'.llxr
(t-T).
