well, thanks. The original problem of longitude escapes me. The clock solution suggests it was a question of messuring the time since departure. Why was the hourglass not used? The time to run them is known, one can turn over many of them when it ran out of sand. Just 1 person each day to look after them. However, even with the time travelled known, it seems to me that the original problem is not well established, because the distance travelled depends on the speed of the boot. But this is not mentioned at all. This all puzzles me.
An hourglass can be used for a good time measurement approximation, but only under good stability (and climate) conditions. Sand is heavily affected by humidity (which is extremely high at sea), and a table at sea is far from being any stable.
With good measure of time, and also knowing that midday is always the moment with the sun furthest from the equator, you can know how far you have travelled east-west. Measuring how high the sun is at midday, you can know how far you have travelled north-south. Combining both, you get to know the distance (and also the speed, but that is the last thing you would know back in the day.).
well, thanks. The original problem of longitude escapes me. The clock solution suggests it was a question of messuring the time since departure. Why was the hourglass not used? The time to run them is known, one can turn over many of them when it ran out of sand. Just 1 person each day to look after them. However, even with the time travelled known, it seems to me that the original problem is not well established, because the distance travelled depends on the speed of the boot. But this is not mentioned at all. This all puzzles me.
An hourglass can be used for a good time measurement approximation, but only under good stability (and climate) conditions. Sand is heavily affected by humidity (which is extremely high at sea), and a table at sea is far from being any stable.
With good measure of time, and also knowing that midday is always the moment with the sun furthest from the equator, you can know how far you have travelled east-west. Measuring how high the sun is at midday, you can know how far you have travelled north-south. Combining both, you get to know the distance (and also the speed, but that is the last thing you would know back in the day.).
I hope that makes sense.
I approached this from another angle:
https://open.substack.com/pub/thomasfdavis/p/the-flat-earth?r=bbwgp&utm_medium=ios
Thanks for sharing!