by land alone, its progress must be slow, and its operations confined. When it is carried on only by sea, its sphere may be more extensive, and its advances more rapid; but it labours under peculiar defects. Though it may make known the position of different countries, and ascertain their boundaries as far as these are determined by the ocean, it leaves us in ignorance with respect to their interior state. Above two centuries and a half have elapsed since the Europeans sailed round the southern promontory of Africa, and have traded in most of its ports; but in a considerable part of that great continent, they have done little more than survey its coasts, and mark its capes and harbours. Its interior regions are in a great measure unknown. The ancients, who had a very imperfect knowledge of its coasts, excepi where the are washed by the Mediterranean or Red Sea, were accustomed to penetrate into its inland provinces, and, if we may rely on the testimony of Herodotus and Diodorus Siculus, had explored many. parts of it now altogether unknown. Unless both modes of discovery be united, the geographical knowledge of the earth must remain incomplete and inaccurate.

NOTE VIII. p. 32.

THE notion of the ancients concerning such an excessive degree of heat in the torrid zone, as rendered it uninhabitable, and their persisting in this error long after they began to have some commercial intercourse with several parts of India lying within the tro-pics, must appear so singular and absurd, that it may not be unacceptable to some of my readers to produce evidence of their holding this opinion, and to account for the apparent inconsistence of their theory with their experience. Cicero, who had bestowed attention upon every part of philosophy known to the aucients, seems to have believed that the torrid zone was uninhabitable, and, of consequence, that there could be no intercourse between the northern and southern temperate zones. He introduces Africanus thus addressing the younger Scipio: " You see this earth encompassed, and, as it were, bound in by certain zones, of which two, at the greatest distance from each other, and sus

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taining the opposite poles of heaven, are frozen with perpetual cold; the middle one, and the largest of all, is burnt with the heat of the sun; two are habitable; the people in the southern one are antipodes to us, with whom we have no connection." Somnium Scipionis, c. 6. Geminus, a Greek philosopher, contemporary with Cicero, delivers the same doctrine, not in a popular work, but in his Eisagoge eis Phainomena, a treatise purely scientific. "When we speak," says he, "of the southern temperate zone and its inhabitants, and concerning those who are called antipodes, it must be always understood that we have no certain knowledge or information concerning the southern temperate zone, whether it be inhabited or not. But from the spherical figure of the earth, and the course which the sun holds between the tropics, we conclude that there is another zone situated to the South, which enenjoys the same degree of temperature with the northern one which we inhabit." Cap. xiii. p. 31. ap. Petavii Opus de Doctr. Tempor. in quo Uranologium sive Systemata var. Auctorum. Amst. 1705. vol. iii. The opinion of Pliny the naturalist with respect to both these points, was the same : "There are five divisions of the earth, which are called zones. All that portion which lies near to the two opposite poles is oppressed with vehement cold and eternal frost. There, unblest with the aspect of milder stars, perpetual darkness reigns, or at the utmost a feeble light reflected from surrounding snows. The middle of the earth, in which is the orbit of the sun, is scorched and burnt up with flames and fiery vapour. Between these torrid and frozen districts lie two other portions of the earth, which are temperate; but, on account of the burning region interposed, there can be no communication between them. Thus Heaven has deprived us of three parts of the earth." Lib. ii. c. 68. Strabo delivers his opinion to the same effect in terms no less explicit: "The portion of the earth which lies near the equator in the torrid zone is rendered uninhabitable by heat." Lib. ii. p. 154. To these I might add the authority of many other respectable philosophers and historians of antiquity.

In order to explain the sense in which this doctrine was general

ly received, we may observe that Parmenides, as we are informed by Strabo, was the first who divided the earth into five zones, and he extended the limits of the zone which he supposed to be unin habitable on account of heat, beyond the tropics. Aristotle, as we learn likewise from Strabo, fixed the boundaries of the different zones in the same manner as they are defined by modern geographers. But the progress of discovery having gradually demonstrated that several regions of the earth which lay within the tropics were not only habitable, but populous and fertile, this induced later geographers to circumscribe the limits of the torrid zone. It is not easy to ascertain with precision the boundaries they allotted to it. From a passage in Strabo, who, as far as I know, is the only author of antiquity from whom we receive any hint concerning this subject, I should conjecture that those who calculated according to the measurement of the earth by Eratosthe nes, supposed the torrid zone to comprehend near sixteen degrees, about eight on each side of the equator; whereas such as followed the computation of Posidonius allotted about twenty-four degrees, or somewhat more than twelve degrees on each side of the equator, to the torrid zone. Strabo, lib. ii. p. 151. According to the former opinion, about two-thirds of that portion of the earth which lies between the tropics was considered as habitable; according to the latter, about one half of it. With this restriction, the doctrine of the ancients concerning the torrid zone appears less absurd; and we can conceive the reason of their asserting this zone to be uninhabitable, even after they had opened a communication with several places within the tropics. When men of science spoke of the torrid zone, they considered it as it was limited by the definition of geographers to sixteen, or at the utmost to twenty-four degrees; and, as they knew almost nothing of the countries nearer to the equator, they might still suppose them to be uninhabitable. In loose and popular discourse, the name of the torrid zone continued to be given to all that portion of the earth which lies within the tropics. Cicero seems to have been unacquainted with those ideas of the later geographers, and adhering to the division of Parmenides, describes the torrid zone as the

largest of the five. Some of the ancients rejected the notion concerning the intolerable heat of the torrid zone as a popular error. This, we are told by Plutarch, was the sentiment of Pythagoras, and we learn from Strabo that Eratosthenes and Polybius had adopted the same opinion, lib. ii. p. 154. Ptolemy seems to have paid no regard to the ancient doctrine and opinions concerning the torrid zone.

NOTE IX. p. 54.

THE Court of inquisition, which effectually checks a spirit of liberal inquiry and of literary improvement, wherever it is established, was unknown in Portugal in the fifteenth century, when the people of that kingdom began their voyages of discovery. More than a century elapsed before it was introduced by John III. whose reign commenced A. D. 1521.

NOTE X. p. 63.

AN instance of this is related by Hackluyt, upon the authori ty of the Portuguese historian Garcia de Resende. Some English merchants having resolved to open a trade with the coast of Guinea, John II. of Portugal dispatched ambassadors to Edward IV. in order to lay before him the right which he had acquired by the pope's bull to the dominion ofthat country, and to request of him to prohibit his subjects to prosecute their intended voyage. Edward was so much satisfied with the exclusive title of the Portuguese, that he issued his orders in the terms which they desired. Hackluyt, Navigations, Voyages, and Traffics of the English, vol. ii. part ii. p. 2.

NOTE XI. p. 76.

THE time of Columbus's death may be nearly ascertained by the following circumstances. It appears from the fragment of a letter addressed by him to Ferdinand and Isabella, A. D. 1501,

that he had, at that time, been engaged forty years in a sea-faring life. In another letter he informs them that he went to sea at the age of fourteen; from those facts it follows that he was born A. D. 1447. Life of Christopher Columbus, by his son Don Ferdinand. Churchill's Collection of Voyages, vol. ii. p. 484, 485.

NOTE XII. p. 83.

THE spherical figure of the earth was known to the ancient geographers. They invented the method, still in use, of computing the longitude and latitude of different places. According to their doctrine the equator or imaginary line which encompasses the earth, contained three hundred and sixty degrees; these they divided into twenty-four parts or hours, each equal to fifteen degrees. The country of the Seres or Sine being the farthest part of India known to the ancients, was supposed by Marinus Tyrius, the most eminent of the ancient geographers before Ptolemy, to be fifteen hours, or two hundred and twenty-five degrees to the East of the first meridian, passing through the Fortunate Islands. Ptolemæi Geogr. lib. i. c. 11. If this supposition was well founded, the country of the Seres, or China, was only nine hours, or one hundred and thirty-five degrees West from the Fortunate or Canary Islands; and the navigation in that direction was much shorter than by the course which the Portuguese were pursuing. Marco Polo, in his travels, had described countries, particularly the island of Cipango or Zipangri, supposed to be Japan, considerably to the East of any part of Asia known to the ancients. Marcus Paulus de Region. Oriental. lib. ii. c. 70. lib. iii. c. 2. Of course, this country, as it extended farther to the East, was still nearer to the Canary Islands. The conclusions of Columbus, though drawn from inaccurate observations, were just. If the suppositions of Marinus had been well founded, and if the countries which Marco Polo visited had been situated to the East of those whose longitude Marinus had ascertained, the proper and nearest course to the East Indies must have been to steer directly West. Herrera, dec. 1. lib. i. c. 2. A more extensive knowledge

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