Thursday  9th October 2025 Presentation

The meeting at the RNA in Welwyn Garden City was very well attended with additional members joining in via a ZOOM link.

Jeremy Batch presented another of his interesting talks, the topic:- 
“Slightly pear-shaped: the story of Mapping and Surveying“.

“Earth is pear-shaped” became headline news in March 1958 when the Vanguard satellite’s orbit deviated from expectations, irreparably confusing a generation of schoolchildren and their geography teachers.
Jeremy gave answers to all of the questions posed below.

That the Earth is round had been known for centuries; that it might also be (very) slightly oval was long-suspected, although we disagreed with the French as to which way the ovalwent.  How did we work it out?
Who was Mercator, how (on Earth) did he make his projection, and why is it not always used?
How did the Swallows and Amazons make their map of the Walton Backwaters with nothing but a compass and a few sticks; how did the Romans give their aqueducts a slope of 1 in 3,000; and how did the Egyptians align their pyramids?
Plus: why, if points had been given for effort, the Prime Meridian really should have run through Paris; how a globe, bought for £150 at a Welsh antiques fair during Covid, then sold at auction for a quarter of a million; and how Gladys West’s model of the Earth allows your GPS to work.

All of teh attendees enjoyed this very interesting talk.  We hope to invite Jeremy back for the next part of this tale next year.