wilds of Beloochistan. Nearchus, the admiral, occupied nearly three months, from September 21 to December 9, 325 B.C., in a coasting voyage to the Persian Gulf, which would be performed at present in little more than a fortnight.

Upon the rise of Alexandria on one of the mouths of the Nile, its position and the activity of its Greek settlers, together with the ruin of Tyre, speedily made it the first commercial mart in the world; and the city became also a great centre of information respecting all known countries, owing to the resort of strangers to it for trading purposes. This stimulated the study of geography in all its branches, the mathematical, physical, and political, by the literati connected with the celebrated library gathered by the Ptolemæan sovereigns. Under Eratosthenes, its president, who was the first to insert parallels of latitude on maps, the attempt was made to measure an arc of the meridian, the first on record, in order to ascertain the magnitude of the globe. The arc fixed upon for the purpose was that between Alexandria and Syene, now Assouan in Upper Egypt, under the Tropic of Cancer. It was known that on the day of the summer solstice the sun was vertical at the latter place. Mention is made of a deep well there, which was visited at the bottom by the direct sunbeams at high noon on the solstitial-day, while vertical bodies threw no shadow for a considerable distance around it. The two places were likewise supposed to be on the same meridian. In possession of these data, Eratosthenes, by means of a concave hemisphere, with a stile fixed in its centre, found that the meridian sun at Syene caused the stile to deflect a shadow at Alexandria, which was one-fiftieth of the whole circumference. Hence he inferred, that the arc of the heavens comprised between the two places must be the same; and that their distance must be a similar arc, or one-fiftieth part of the terrestrial circuit. On estimating their distance by the difference of latitude, it was found to be 5000 stadia, which multiplied by 50, gave 250,000 stadia for the circumference of the globe. As we are ignorant of the stadium employed, the result cannot be expressed in common measures. But several important errors were committed in the practical application of a right principle, for instead of the two places being under the same meridian, they differ nearly three degrees in longitude. Great credit, however, belongs to Eratosthenes, and he was honoured by his contemporaries as the Surveyor of the Earth, the Measurer of the Universe.

The Romans, in their career of conquest, rendered familiar various countries known before, though obscurely on the west, south, and east. Spain was traversed by the legions under the Scipios; Numidia and Mauritania were explored during the Jugurthine war; Armenia and the defiles of the Caucasus were penetrated in the contest with Mithridates. But northward, Julius Cæsar may be said to have made great discoveries. Before his campaigns in Gaul and Britain, of which he became the historian, the civilised world was completely ignorant of their interior regions. He found the maritime provinces of our island in the south, occupied by a Germanic race, the Belge, in the enjoyment of considerable social comfort-inhabiting towns, and possessing abundance of cattle. In the next age, the Augustan, soon after the commencement of the Christian era, Strabo produced his Geography, in which minute details are given, chiefly of the regions visited by the Roman arms, founded partly upon his own observation as a traveller, and partly upon report. But ample evidence is afforded in his work of the imperfect state of knowledge. Thus, he was dubious respecting the shape of Italy, whether a square or a triangle. He represented the Pyrenees as running north and south; thought the coasts of Spain and Gaul formed nearly a straight line; and connected the Caspian with the Northern Ocean. Africa, he considered, did not extend far to the south, a fortunate error, as it stimulated the Portuguese to attempt its circumnavigation. Deeming the earth a sphere, and the southern hemisphere to correspond to the northern, Strabo divided

it into five zones; one torrid, between the tropics, a region of burning heat, and consequently uninhabitable; two frigid, towards the poles, void of life from the intense cold; and two intervening temperate zones, favoured with a moderate temperature, admitting of the existence of man, animals, and plants. The remarkable speculation also occurs, that where the temperate zone crosses the Atlantic Ocean, 'there are inhabited worlds, distinct from that in which we dwell.'

Under the early emperors, Midland and Northern Europe were further disclosed by the Roman generals. Drusus led his soldiers to the river Weser in Germany; and Germanicus marched to the Ems and the Elbe. South Britain, into which Cæsar merely made a foray, was conquered in the time of Claudius, and constituted a province of the empire. North Britain, up to the foot of the Grampians, was traversed by the troops under Agricola, who sent out a fleet from the Firth of Forth on a voyage of discovery northward, which made the circuit of the shores. This fleet,' says Tacitus, the son-in-law of the general, 'first ascertained that Britain was an island. It discovered also and subjected the Orcades (Orkneys), a cluster of islands not known before, and saw Thule hitherto concealed by snow and winter.' But the historian had a very erroneous idea of the position of our islands, for Britain is said to have Spain on the west, and Ireland is placed midway between the two. The earliest mention of Scandinavia occurs at this time; in the pages of Pliny, it is represented as an island of unknown extent, separated by an arm of the sea from the Cimbrian Peninsula, the modern Jutland, and marked by a mountain called Sevo; the existing name of a hill near Gottenburg. Norway is apparently indicated by the same writer under the name of Nerigon, the inhabitants of which are said to have customarily sailed as far as Thule. An adventurous traveller from Pannonia to the amber country made the Baltic, near the mouth of the Vistula, known to the Romans; information was acquired by them of the tribes on the coast, up to the Gulf of Finland; the Sviones, sea-men, or Swedes, are mentioned; but they were never aware that Scandinavia was an integral portion of Europe. The rumour also reached them in Spain, of islands existing in the Atlantic, off the coast of Africa-the Fortunate Isles of Pliny, believed to be the Canaries-but their knowledge of them was limited to the tidings.

In the second century of our era, during the reigns of the Antonines, the best scholar of his age flourished at Alexandria. This was Ptolemy, a discoverer, observer, and careful compiler, who, from the recorded experience of ages, and the itineraries of merchants resorting to the city, produced a Geography, in eight books, accompanied with maps, which remained a text-book through the middle ages, and was not superseded till the fifteenth century. He announced with certainty the existence. of the Niger, flowing from west to east; described correctly the course of the Volga; but erred egregiously in many of his delineations. The north coast of Africa is made nearly a straight line; Scotland has its greatest extent east and west; the Mediterranean is stretched out to nearly double its proper length; the whole peninsula of India is suppressed; Ceylon is enormously exaggerated in its dimensions; and Asia is prolonged to the south, then brought round westward to join Africa, thus enclosing the Indian Ocean. But the descriptive department of geography was foreign to the aim of the writer. His object was to fix the astronomical position of places by means of parallels and meridians, which, though in use before, were far more largely applied by him, and indicated as measurers of latitude and longitude. Ptolemy's chief parallels are the equator; that of 16° north, through Meroë; that of 36°, through Rhodes, an old standard line; and that of 63°, through Thule, with which the latitude of the Shetlands, the supposed Thule, nearly agrees. But

he greatly erred in his longitudes, which were computed from the meridian passing through the Fortunate or Canary Islands as a starting-point. He made the length of the Mediterranean 20° more than its true measure, and placed the mouth of the Ganges 46° eastward of its real position, an error of about three thousand miles, equal to one-eighth of the circumference of the globe. This exaggerated eastern longitude had, however, the happy effect of leading the navigators of the fifteenth century, who knew nothing of the true dimensions of the globe, to imagine that India and China lay at no great distance across the waters of the western ocean, and confirmed them in their purpose to attempt its passage.

The world, as known to the ancient civilised nations, may be generally defined as extending from the extremity of Britain on the north, to the banks of the Upper Nile on the south, and from the shores of the Atlantic on the west, to the borders of China on the east. It thus embraced but a small proportion of the terrestrial surface, little more than the half of Europe, a fourth of Asia, and a fifth of Africa. But within the limits named, there was a vast area, very vaguely disclosed, while the most erroneous conceptions were entertained of the extent and configuration of long visited lands; and even such a familiar circumstance as the annual inundation of the Nile was an unsolved problem. It was commonly ascribed to the special interposition of the Deity; and though Lucretius rightly mentions periodical rains. towards the equator as one cause, he gives greater prominence to the influence of the Etesian winds, which have no effect at all in arresting the current of the river, and speaks of the event as without a parallel on the face of the globe.

The connection between the flow and ebb of the sea, and the positions of the moon, was too obvious to have escaped the attention of mankind, whose geographical position brought oceanic phenomena under their notice in early ages. Accordingly, the variation of the tides with the moon was remarked by physical inquirers; and Pliny, in a striking passage of his Natural History, directly attributes them to lunar action, and gives an accurate description of their leading features. But in the prior age of Alexander, the Greeks, although not ignorant of the ordinary tides, beheld with surprise and dismay the bore, or rushing tide of the Indus, common to the mouths of most great rivers; and to Cæsar, the higher tidal rise on the coast of Britain, at the period of the full moon, which damaged his fleet, was an entirely unexpected event. But it is remarkable that references occur to the phenomena of high northern latitudes, certainly never visited by any of the ancients, which must have either been deduced by reasoning from facts observed elsewhere, or supplied to northern voyagers by those with whom they communicated, who had heard of them. Thus the sea is said to be languid and nearly motionless in that direction; the sun is described as neither rising nor setting, but going round the horizon; and the figures of the gods are affirmed to appear there covered with luminous beams. These are evidently allusions to the ice-bound ocean, and the long summer day of the polar circle, with the brilliant coruscations of the aurora borealis.

The wonderful power of the magnet, by which it attracts iron, was not unknown to the ancients. In fact, from Magnesia, in Asia Minor, where the Greeks first met with a kind of iron-ore endowed with it, we have the terms 'magnet' and 'magnetism.' But they were not aware that the property could be communicated to the iron attracted, so that artificial magnets might be readily constructed; and the polarity of the magnet, or its property of pointing, when freely suspended, towards the poles of the earth, on which account our ancestors gave it the name of loadstone, leading or guiding stone, was either not discovered, or not taken advantage of. From obscure

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intimations, it may be gathered that the Chinese were acquainted with this quality, as exemplified in the mariner's compass, prior to the Christian era; but as they neither learned the habitual application of it, nor acquired any proficiency in the art of navigation, it was practically useless to them. The same knowledge has been assigned to Solomon, on account of the voyages he ordered; and the Arabians are said to have used the compass at an early period to guide them through the trackless sands of the desert. But these are ill-supported assertions. The voyages directed by Solomon, though comparatively distant, were doubtless simply coasting expeditions, and the latter people were found in the sixteenth century steering wholly by the stars or by the land. It is very likely that the germs of this, as of other important applications of natural phenomena, have long been known in the world; but it is certain that the magnetic needle, as an instrument of use, belongs entirely to the modern age, and is due to the practical genius of Western Europe.

NEW era dawns. The disorganised state of society which attended and followed the fall of the Roman empire, had the effect of obscuring the light of science kindled in past ages, repressing the spirit of inquiry, and interfering with the cultivation of all kinds of knowledge. A few solitaries pored over manuscripts and maps in monastic cells; ecclesiastics went out to proclaim a new faith to the barbarians who had overthrown the ancient civilisation, and thus changed their landscapes; enthusiasts repaired on pilgrimage to the sacred shrines of the Holy Land; but no services of moment were rendered to geography in disclosing fresh regions, or illustrating those previously known, till the ninth century, in which our own King Alfred took part. At that period a fresh race of disturbers, issuing chiefly from the archipelagoes of Denmark and Norway, made themselves formidable to the settled and gradually improving maritime communities of Europe. They are variously styled Norsemen or Northmen and Danes by our own annalists, Normans by the French, and Normanni by the Italians, for their cruises extended from the stormy rocks of the Shetlands to the balmy shores of the Mediterranean, and permanent settlements were made by them in Britain, France, and Italy. Their creed was a ferocious paganism; their standard, the ominous raven; their profession, piracy. Originally haunting inlets of the coast, bays, and estuaries,