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Science (mostly history, and mostly gravity)

Chasing the history of the gravity method sometimes took me down side-tracks that did not quite fit the theme, and so never made it into ‘The Hunt’. Also, and inevitably, there were stories that should have been in ‘The Hunt’ but which I missed. Here are some of them, and bits of new Earth Science are sometimes included!

Shark Bay: a problem with pendulums

Louis de Freycinet elected not to use the method of coincidences when making pendulum observations on hos circumnavigation in the Uranie. There are, however, all sorts of difficulties in discovering what he actually did do.

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Airy’s error

The experiment described by George Airy in his 1857 paper entitled “Account of pendulum experiments undertaken in the Harton colliery, for the purpose of determining the mean density of the Earth” produced an estimate of the mean density of the Earth that was 20% in error. Why was this?

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Airy under ground

After his failure to measure the mean density of the Earth in the Dolcoath mine in Cornwall in 1826, George Airy waited 30 years before making another attempt. For this he went to the Harton Pit near South Shields and used innovations such as electrical signalling. But was he any more successful?

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A new statue in Zagreb

The Republic of Croatia can lay claim to being the homeland of two scientists whose names are, if not exactly household words, have at least integrated themselves into the international vocabulary., but until April 2022, only one of them had a statue in Zagreb.

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More airmag history – and a bit of interpretation

Between 1967 and 1913 aeromagnetic surveys were flown over eastern Papua New Guinea, but the results only became available during the country’s transition to full independence. Overlooked at the time, they now seem to have been largely forgotten

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Cobar – aeromagnetic pioneer

In early 1963 Australia’s Bureau of Mineral Resources, the BMR. carried out the first airborne proton magnetometer survey in the country, using the instrument designed and largely built by John Newman.

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Who now remembers MIN?

In December 2021, someone from the South Australia Department of Mines and Energy posted a historical note on LinkedIn., with pictures of survey aircraft VH-BUR. It brought vividly to mind the sight, and odour, of her companion, VH-MIN

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Wherein lieth the fault?

A paper published in 2014 shows two possible locations for the Owen Stanley Fault Zone in eastern Papua, one based on gravity, the other on geology. Which is right?

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A potato for a geoid

In mid-October 2021 an image of the geoid based on data from NASA’s GRACE satellite was posted on LinkedIn. It was an object lesson in the perils of attempting to disseminate science via a platform that restricts posts to 2500 characters and comments to 1250 characters.

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