Comments by "" (@craigkdillon) on "Get to the Point" channel.

BTW...the Roman mile was 1,000 DOUBLE paces. A double-pace is about 6 feet, so a mile was 6,000 feet.
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1. I recall that it was one of the Ptolemy's that calculated the Circumference of the Earth. He used the shadow of an obelisk at the same time the sun shown down a well that was miles away. Knowing the distance, and the angle, it was a simple calculation. 2. You need to climb to measure the angles of the shadows of TWO buildings miles apart to perform the calculation. ONE building won't do it.
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@spanqueluv9er chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.mpiwg-berlin.mpg.de/sites/default/files/Preprints/P464.pdf Eratosthenes worked in Alexandria at the time of Ptolemy. Ptolemy worked on it, too. This paper refers to both of them. Another guy on Rhodes was also working on it at that time. Seems to have been a big topic circa 200 BC.
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@w.reidripley1968 The question is how did the Romans measure it? They did not use what a normal person's stride is but a fit soldier in the legion. I think it was closer to 3 feet. When you walk for speed and distance, you take longer strides. 2.5 feet is what I do when I am strolling not walking with pace.
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@divingfe Yes.
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