After these agreeable courtesies, the little fleet raised its anchors and sailed west. Columbus sent one caravel to investigate the river. Finding that he should not succeed in that direction, and that he had no available way either north or south, he leaves by the same entrance by which he had entered. The water is still very fresh, and he is satisfied, correctly as we know, that these currents were caused by the entrance of the great river of water.

On the thirteenth of August he leaves the island by what he calls the northern mouth of the river (Boca Grande), and begins to strike salt water again.

At this part of Columbus’s letter there is a very curious discussion of temperature, which shows that this careful observer, even at that time, made out the difference between what are called isothermal curves and the curves of latitude. He observes that he cannot make any estimate of what his temperature will be on the American coast from what he has observed on the coast of Africa.

He begins now to doubt whether the world is spherical, and is disposed to believe that it is shaped like a pear, and he tries to make a theory of the difference of temperature from this suggestion. We hardly need to follow this now. We know he was entirely wrong in his conjecture. “Pliny and others,” he says, “thought the world spherical, because on their part of it it was a hemisphere.” They were ignorant of the section over which he was sailing, which he considers to be that of a pear cut in the wrong way. His demonstration is, that in similar latitudes to the eastward it is very hot and the people are black, while at Trinidad or on the mainland it is comfortable and the people are a fine race of men, whiter than any others whom he has seen in the Indies. The sun in the constellation of the Virgin is over their heads, and all this comes from their being higher up, nearer the air than they would have been had they been on the African coast.

With this curious speculation he unites some inferences from Scripture, and goes back to the account in the Book of Genesis and concludes that the earthly Paradise was in the distant east. He says, however, that if he could go on, on the equinoctial line, the air would grow more temperate, with greater changes in the stars and in the water. He does not think it possible that anyone can go to the extreme height of the mountain where the earthly Paradise is to be found, for no one is to be permitted to enter there but by the will of God, but he believes that in this voyage he is approaching it.

Any reader who is interested in this curious speculation of Columbus should refer to the “Divina Comedia” of Dante, where Dante himself held a somewhat similar view, and describes his entrance into the terrestrial paradise under the guidance of Beatrice. It is a rather curious fact, which discoverers of the last three centuries have established, that the point, on this world, which is opposite the city of Jerusalem, where all these enthusiasts supposed the terrestrial Paradise would be found, is in truth in the Pacific Ocean not far from Pitcairn’s Island, in the very region where so many voyagers have thought that they found the climate and soil which to the terrestrial Paradise belong.

Columbus expresses his dissent from the recent theory, which was that of Dante, supposing that the earthly Paradise was at the top of a sharp mountain. On the other hand, he supposes that this mountain rises gently, but yet that no person can go to the top.

This is his curious “excursion,” made, perhaps, because Columbus had the time to write it.

The journal now recurs to more earthly affairs. Passing out from the mouth of the “Dragon,” he found the sea running westward and the wind gentle. He notices that the waters are swept westward as the trade winds are. In this way he accounts for there being so many islands in that part of the earth, the mainland having been eaten away by the constant flow of the waves. He thinks their very shape indicates this, they being narrow from north to south and longer from east to west. Although some of the islands differ in this, special reasons maybe given for the difference. He brings in many of the old authorities to show, what we now know to be entirely false, that there is much more land than water on the surface of the globe.

All this curious speculation as to the make-up of the world encourages him to beg their Highnesses to go on with the noble work which they have begun. He explains to them that he plants the cross on every cape and proclaims the sovereignty of their Majesties and of the Christian religion. He prays that this may continue. The only objection to it is the expense, but Columbus begs their Highnesses to remember how much more money is spent for the mere formalities of the elegancies of the court. He begs them to consider the credit attaching to plans of discovery and quickens their ambition by reference to the efforts of the princes of Portugal.