It is, however, a piece of justice due to the memory of these great men, to acknowledge that we are equally encouraged by their examples and guided by their discoveries. We owe to them the being freed, not only from the errors, but from the doubts and difficulties with which former ages were oppressed; to them we stand indebted for the discovery of the best part of the world, which was entirely unknown to the ancients, particularly some part of the eastern, most of the southern, and all the western hemisphere; from them we have learned that the earth is surrounded by the ocean, and that all the countries under the torrid zone are inhabited, and that, quite contrary to the notions that were formerly entertained, they are very far from being the most sultry climate in the world, those within a few degrees of the tropics, though habitable, being much more hot, for reasons which have been elsewhere explained. By their voyages, and especially by the observations of Columbus, we have been taught the general motion of the sea, the reason of it, and the cause and difference of currents in particular places, to which we may add the doctrine of tides, which were very imperfectly known, even by the greatest men in former times, whose accounts have been found equally repugnant to reason and experience.
By their observations we have acquired a great knowledge as to the nature and variation of winds, particularly the monsoons, or trade winds, and other periodical winds, of which the ancients had not the least conception; and by these helps we not only have it in our power to proceed much farther in our discoveries, but we are likewise delivered from a multitude of groundless apprehensions, that frightened them from prosecuting discoveries. We give no credit now to the fables that not only amused antiquity, but even obtained credit within a few generations. The authority of Pliny will not persuade us that there are any nations without heads, whose eyes and mouths are in their breasts, or that the Arimaspi have only one eye, fixed in their forehead, and that they are perpetually at war with the Griffins, who guard hidden treasures; or that there are nations that have long hairy tales, and grin like monkeys. No traveller can make us believe that, under the torrid zone, there are a nation every man of which has one large flat foot, with which, lying upon his back, he covers himself from the sun. In this respect we have the same advantage over the ancients that men have over children; and we cannot reflect without amazement on men's having so much knowledge and learning in other respects, with such childish understandings in these.
By the labours of these great men in the two last centuries we are taught to know what we seek, and how it is to be sought. We know, for example, what parts of the north are yet undiscovered, and also what parts of the south. We can form a very certain judgment of the climate of countries undiscovered, and can foresee the advantages that will result from discoveries before they are made; all which are prodigious advantages, and ought certainly to animate us in our searches. I might add to this the great benefits we receive from our more perfect acquaintance with the properties of the loadstone, and from the surprising accuracy of astronomical observations, to which I may add the physical discoveries made of late years in relation to the figure of the earth, all of which are the result of the lights which these great men have given us.
