‘Is a degree in Physics a necessary prerequisite to argue that an anecdote in history is not well documented (or perhaps even to write history of science)?’

WGM2012 shows that the highest Earth-surface free-air gravity anywhere in the world is about +970 mGal in the Sierra Nevada de Santa Marta in NE Colombia. But there are problems with those values.

In 1819, between the 19th and 25th of May, Louis de Freycinet, with the help of some of his officers from the corvette Uranie, used pendulums to measure gravity in Port Louis, the capital of Mauritius.

Scepticism is great, and vitally important in any science, but when science itself is under attack, anyone who claims to be a scientist needs to stand up and defend it.

Extremes are now again fashionable in many areas of life. But – extreme gravity? Is there anything to be gained by searching for those points on the Earth’s surface where gravity is highest, lowest, steepest?

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,

In 2008 Ken Amor and a group of his colleagues from Oxford and Aberdeen universities published a reinterpretation of the Stac Fada member of the Stoer Group sediments that outcrop on Stoer beach and in some other similar localities in the northwest of...