Pendulum gravity on Guam
In 1819 Louis de Freycinet measured gravity on Guam using four pendulums, and in 1828 Fyodor Litke did the same thing, with just one pendulum. How well did they do?
In 1819 Louis de Freycinet measured gravity on Guam using four pendulums, and in 1828 Fyodor Litke did the same thing, with just one pendulum. How well did they do?
The astronomer John Goldingham makes an appearance in ‘The Hunt for Earth Gravity’ on account of pendulum measurements he made in his observatory in Madras (modern Chennai), but he has another claim to fame. He was responsible the first gravity measurements made in Sumatra or, rather, on one of its offshore islands.
For magnetic surveys, power lines are a nuisance. Normal AC lines can interfere with magnetometer electronics if you get too close. But what about DC lines? Just forget about working anywhere near them.
There has to be a point on the Earth’s surface where the effect of geology on gravity is greatest. With the sea-covered areas unlikely settings because of the low density of sea water and almost all land areas now covered to some extent by gravity surveys, it is possible to say, with a fair degree of confidence, where that place is. It is on the largest of the Bonin (or Ogasawara) Islands, Chichi-jima,