The meridian arc surveyed by Nicolas-Louis de Lacaille north of Cape Town in 1752  was affected by VD. The resulting discrepancy with Northern Hemisphere measurements was not explained until a visit to the area by George Everest in 1820.
The meridian arc measurement made by Nicolas-Louis de Lacaille north of Cape Town in 1752 (de Lacaille's arc measurement) was affected by VD. The resulting discrepancy with Northern Hemisphere measurements was not explained until a visit to the area by George Everest in 1820; Maclear's arc measurement resurvey ultimately confirmed Everest's conjecture. .
R
surveyed
measurement made
A
(de Lacaille's arc measurement)
R
1820.
1820; Maclear's arc measurement resurvey ultimately confirmed Everest's conjecture. .