If there's anything Columbus should be known for, as respects the size and shape of the Earth, it was using unrealistically low numbers for the circumference of the Earth! His estimates, that he used to convince others that one could sail from Europe directly to India (were the Americas non-existant), were absurdly small! Had the Americas not existed, he and his crew surely would have starved before reaching Asia!Spot on. Now, as Theodore Sturgeon used to say, Ask the next question. Where did Columbus get his wildly inaccurate estimate of the circumference of the earth? (Or, at least, of the size of the ocean between Europe and the Indies.) The answer is from 4 Ezra 6:42-52:
 "On the third day thou didst command the waters to be gathered together in the seventh part of the earth; six parts thou didst dry up and keep so that some of them might be planted and cultivated and be of service before thee.My emphasis. The key point is the repeated assertion that the waters, that is the oceans, make up only one-seventh of the earth. Therefore, one might infer that the Atlantic ocean could not have been all that big and that it would not be a difficult project to sail across it to the Indies. Columbus, in fact, made this very argument to Ferdinand and Isabella using this text, and apparently they were convinced, since they gave him their support.*
 For thy word went forth, and at once the work was done.
 For immediately fruit came forth in endless abundance and of varied appeal to the taste; and flowers of inimitable color; and odors of inexpressible fragrance. These were made on the third day.
 "On the fourth day thou didst command the brightness of the sun, the light of the moon, and the arrangement of the stars to come into being;
 and thou didst command them to serve man, who was about to be formed.
 "On the fifth day thou didst command the seventh part, where the water had been gathered together, to bring forth living creatures, birds, and fishes; and so it was done.
 The dumb and lifeless water produced living creatures, as it was commanded, that therefore the nations might declare thy wondrous works.
 "Then thou didst keep in existence two living creatures; the name of one thou didst call Behemoth and the name of the other Leviathan.
 And thou didst separate one from the other, for the seventh part where the water had been gathered together could not hold them both.
 And thou didst give Behemoth one of the parts which had been dried up on the third day, to live in it, where there are a thousand mountains;
 but to Leviathan thou didst give the seventh part, the watery part; and thou hast kept them to be eaten by whom thou wilt, and when thou wilt. (RSV)
The moral? Everyone should read the Old Testament pseudepigrapha, but don't use them to make your travel plans.
*For more details, see Alastair Hamilton, The Apocryphal Apocalypse: The Reception of the Second Book of Esdras (4 Ezra) from the Renaissance to the Enlightenment (Oxford: Clarendon, 1999), 27-29.
Cross-file under "Pseudepigrapha Watch."