Learning exercise 1: who first stipulated that the earth was round?

messenjah of oneEratosthenes. He not only detrmined earth was round but calculated its circumference. There may have been earlier references to the disappearing of ships upon the horizon and the idea of a round earth being put forward before this though.

messenjah of one Such is the nature of learning. Credibilty stands or falls on the weight of investigation and good research.

iano How does that make a bit of difference. In the same way that the proper interpretation is used for circle in IS 40:22 the proper interpretation for Is 22:18 is ball. And in the context of the passage it is clear that the concept of a sphere is known.
That it is used in Is 22:18 but not in Is 40:22 makes it clear that the concept used is different.
This is perfectly in keeping with observations they could make since from the vantage of a hilltop one may look out to the horizon about you and see the circular nature thereof. One cannot,however,see the true nature of the planet as spherical. Though one may assume they were vaguely aware of the possibilty it is not evident from the passages.That said Isaiah is not a wealth of accurate understanding of the nature of the planet.