Chapter III (9)

Of the remainder of the Periplus little notice is requisite, the account of the countries beyond Cape Comorin being entirely drawn from report, and consequently erroneous, both in respect to geography and commerce. In some particulars regarding the latter, however, it is surprisingly accurate: the Gangetic muslins are praised as the finest manufacture of the sort, and Gangetic spikenard is also noticed; the other articles of traffic in the ports on the Ganges were betel and pearls. Thina is also mentioned as a city, in the interior of a country immediately under the north, at a certain point where the sea terminates; from this city both the raw material and manufactured silks are brought by land through Bactria to Baragaza, or else down the Ganges, and thence by sea to Limurike: the routes we have already described. The means of approach to Thina are represented as very difficult; some merchants, however, came from it to a great mart which is annually held near it. The Sesatoe, who from the description of them are evidently Tartars, frequent this mart with their wives and children. "They are squat and thick-set, with their face broad and their nose greatly depressed. The articles they bring for trade are of great bulk, and inveloped in mats made of rushes, which, in their outward appearance, resemble the early leaves of the vine. Their place of assembly is between their own borders and those of China; and here spreading out their mats, they hold a fair for several days, and at the conclusion of it, return to their own country in the interior. Upon their retreat the Thinæ, who have continued on the watch, repair to the spot and collect the mats which the strangers left behind at their departure; from these they pick out the haulm, and drawing out the fibres, spread the leaves double, and make them into balls, and then pass the fibres through them. Of these balls there are three sorts, in this form they take the name of Malabathrum."

On this account Dr. Vincent very justly remarks, that we have here, upon the whole, a description of that mode of traffic, which has always been adopted by the Chinese, and by which they to this hour trade with Russia, Thibet, and Ava.

Many of the particulars which we have given on the subject of the Roman trade are supplied by Pliny, who wrote his natural history when Rome was in its most flourishing state under the reign of Vespasian. His works consist of thirty-seven books, the first six comprise the system of the world and the geography as it was then known. After examining the accounts of Polybius, Agrippa, and Artemidorus, he assigns the following comparative magnitudes to the three great divisions of the earth. Europe rather more than a third, Asia about a fourth, and Africa about a fifth of the whole. With few exceptions, his geographical knowledge of the east and of the north, the parts of the world of which the ancients were the most ignorant, was very inaccurate: he supposes the Ganges to be the north-eastern limit of Asia, and that from it the coast turned to the north, where it was washed by the sea of Serica, between which and a strait, which he imagined formed a communication from the Caspian to the Scythian ocean, he admits but a very small space. According to the system of Pliny, therefore, the ocean occupied the whole county of Siberia, Mogul Tartary, China, &c. He derived his information respecting India from the journals of Nearchus, and the other officers of Alexander; and yet such is his ignorance, or the corrupt state of the text, or the vitiated medium through which he received his information, that it is not easy to reconcile his account with that of Nearchus. Salmasius, indeed, charges him with confounding the east and west in his description of India. His geography, in the most important particular of the relative distances of places, is rendered of very little utility or authority, from the circumstance pointed out and proved by D'Anville, that he indiscriminately reckons eight stadia to the mile, without reference to the difference between the Greek and Roman stadium. He has, however, added two articles of information to the geographical and commercial knowledge of the east possessed before his time; the one is the account of the new course of navigation from Arabia to the coast of Malabar, which has been already described; the other is a description of Trapobane, or Ceylon, which, though inaccurate and obscure in many points, must be regarded as a real and important addition to the geographical knowledge of the Romans.

Pliny's geography of the north is the most full and curious of all antiquity. After describing the Hellespont, Moeotis, Dacia, Sarmatia, ancient Scythia, and the isles in the Euxine Sea, and proceeding last from Spain, he passes north to the Scythic Ocean, and returns west towards Spain. The coast of part of the Baltic seems to have been partly known to him; he particularly mentions an island called Baltia, where amber was found; but he supposes that the Baltic Sea itself was connected with the Caspian and Indian Oceans. Pliny is the first author who names Scandinavia, which he represents as an island, the extent of which was not then known; but by Scandinavia there is reason to believe the present Scandia is meant. Denmark may probably be rcognised in the Dumnor of this author, and Norway in Noligen. The mountain Soevo, which he describes as forming a vast bay called Codanus, extending to the promontory of the Cimbri, is supposed by some to be the mountains that run along the Vistula on the eastern extremity of Germany, and by others to be that chain of mountains which commence at Gottenburgh. The whole of his information respecting the north seems to have been drawn from the expeditions of Drusus, Varus, and Germanicus, to the Elbe and the Weser, and from the accounts of the merchants who traded thither for amber.

Tacitus, who died about twenty years after Pliny, seems to have acquired a knowledge of the north more accurate in some respects than the latter possessed. In his admirable description of Germany, he mentions the Suiones, and from the name, as well as other circumstances, there can be little doubt that they inhabited the southern part of modern Sweden.

The northern promontory of Scotland was known to Diodorus Siculus under the name of Orcas; but the insularity of Britain was certainly not ascertained till the fleet sent out by Agricola sailed round it, about eighty-four years after Christ. Tacitus, who mentions this circumstance, also informs us, that Ireland, which was known by name to the Greeks, was much frequented in his time by merchants, from whose information he adds, that its harbours were better known than those of Britain: this statement, however, there is much reason to question, as in the time of Cæsar, all that the Romans knew of Ireland was its relative position to Britain, and that it was about half its size.

The emperor Trajan, who reigned between A.D. 98 and A.D. 117, was not only a great conqueror, carrying the Roman armies beyond the Danube into Dacia, and into Armenia, Mesopotamia, and Assyria, and thus extending and rendering more accurate the geographical knowledge of his subjects; but he was also attentive to the improvement and commercial prosperity of the empire. He made good roads from one end of the empire to the other; he constructed a convenient and safe harbour at Centum Cellæ (Civita Vecchia), and another at Ancona on the Adriatic: he dug a new and navigable canal, which conveyed the waters of the Nahar-Malcha, or royal canal of Nebuchadnezzar, into the river Tigris; and he is supposed to have repaired or renewed the Egyptian canal between the Nile and the Red Sea. He also gave directions and authority to Pliny, who was appointed governor of Pontus and Bithynia, to examine minutely into the commerce of those provinces, and into the revenues derived from it, and other sources.

The emperor Adrian passed nearly the whole of his reign in visiting the different parts of his dominions: he began his journey in Gaul, and thence into Germany; he afterwards passed into Britain. On his return to Gaul, he visited Spain; on his next journey he went to Athens, and thence into the east; and on his second return to Rome, he visited Sicily; his third journey comprised the African provinces; his fourth was employed in again visiting the east; from Syria he went into Arabia, and thence into Egypt, where he repaired and adorned the city of Alexandria, restoring to the inhabitants their former privileges, and encouraging their commerce. On his journey back to Rome, he visited Syria, Thrace, Macedonia, and Athens. By his orders, an artificial port was constructed at Trebizond on a coast destitute by nature of secure harbours, from which this city derived great wealth and splendour.

The only writer in the time of Adrian, from whom we can derive any additional information respecting the geography and trade of the Romans, is Arrian. He was a native of Nicodemia, and esteemed one of the most learned men of his age; to him we are indebted for the journal of Nearchus's voyage, an abstract of which has been given. His accuracy as a geographer, is sufficiently established in that work, and indeed, in almost all the particulars respecting India, which he has detailed in his history of the expedition of Alexander the Great; and in his Indica, which may be regarded as an appendix to that history. He lived at Rome, under the emperors Adrian, Antoninus, and Marcus Aurelius, and was preferred to the highest posts of honour, and even to the consulship. In the year A.D. 170, he was appointed governor of Pontus, by Adrian, for the special purpose of opposing the Alani, who were invading that part of the empire. His situation and opportunities as governor, enabled him to derive the most accurate and particular information respecting the Euxine Sea, which he addressed in a letter to Adrian; this Periplus, as it is called, "contains whatever the governor of Pontus had seen, from Trebizond to Dioscurias; whatever he had heard from Dioscurias to the Danube and whatever he knew from the Danube to Trebizond."

The letter begins with the arrival of Arrian at Trebizond, at which place, the artificial port already noticed was then forming. At Trebizond he embarked, and surveyed the eastern coast of the Euxine Sea, visiting every where the Roman garrisons. His course led him past the mouth of the Phasis, the waters of which, he remarks, floated a long time on those of the sea, by reason of their superior lightness. A strong garrison was stationed at the mouth of this river, to protect this part of the country against the Barbarians; he adds, however, in his letter, that the new suburbs which had been built by the merchants and veterans, required some additional defence, and that he had, accordingly, for the greater security of the place, strengthened it with a new ditch: he ended his voyage at Sebastapolis, the most distant city garrisoned by the Romans. The description of the coasts of Asia, from Byzantium to Trebizond, and another of the interior, from Sebastapolis to the Bosphorus Cimmerius, and thence to Byzantium, is added to his voyage. The great object of this minute and accurate survey was to enable the emperor to take what measures he might deem proper, in case he designed to interfere in the affairs of the Bosphorus, as well as to point out the means of defence against the Alani, and other enemies of the Roman power.

We have contented ourselves with this short abstract of the Periplus of the Euxine, because we have already given all the important information it contains on the subject of the commerce of this sea. It is very inferior in merit to the Periplus of the Euxine, which has also been attributed to this Arrian, though Dr. Vincent, we think, has proved that it is the work of an earlier writer, and of a merchant.

As the Roman conquests extended, their geographical knowledge of course increased. In the reign of Antoninus Pius, their armies had forced a passage much further north in Britain than they had ever ventured before. One of the results of this success was a maritime survey, or rather two partial surveys of the north part of Britain, from which the geography of that part of the island was compiled by Ptolemy.

The maritime laws of the Rhodians, or those which passed under their name, seem to have been the basis and authority of the Roman maritime laws at this period; for we are told, that when a merchant complained to the emperor that he had been plundered by the imperial officers at the Cyclades, where he had been shipwrecked, the latter replied, that he indeed was lord of the earth, but that the sea was governed by the Rhodian laws, and that from them he would obtain redress. This part of the Rhodian law, however, had been but lately adopted by the Romans; for Antoninus is expressly mentioned as having enacted, among other laws, that shipwrecked merchandize should be the entire property of the lawful owners, without any interference or participation of the officers of the exchequer, and that those who were guilty of plundering wrecks should be severely punished.

One of the most important and complete surveys of the Roman empire (the idea of which, as has been already stated, was first formed by Julius Cæsar) was begun and finished in the reign of Antoninus, and is well known under the appellation of his Itinerary. It has, indeed, been objected to this date of the Itinerary, that it contains places which were not known in the time of Antonine, and names of places which they did not bear till after his reign; thus mention is made of the province of Arcadia in Egypt, and of Honorius in Pontus, so styled in honor of the sons of the emperor Theodosius. But the fact seems to be that alterations and additions were made to the Itinerary, and that occasionally, or perhaps under each subsequent emperor, new editions of it were published. From the maritime part of this Itinerary of Antoninus we derive a clear idea of the timidity or want of skill and enterprise of the Mediterranean seamen in their commercial voyages. All the ports which it was prudent or necessary, for the safety of the voyage, to touch at, in sailing from Achaia to Africa are enumerated; and of these there are no fewer than twenty, some of them at the heads of bays on the coasts of Greece, Epirus, and Italy, and within the Straits of Sicily as far as Messina. Their course was then to be directed along the east and south coasts of Sicily to the west point of it; from an island off this point they took their departure for the coast of Africa, a distance of about ninety miles.

These Itineraries undoubtedly were drawn up in as accurate a manner as possible; but till the time of Ptolemy they were of little service to geography or commerce, as, for a private individual to have one in his possession was deemed a crime little short of high treason. Geography as a science, therefore, had hitherto made little advances; indeed the discovery and example of Hipparchus, of reducing it to astronomical basis, seems to have been forgotten or neglected till the middle of the second century. The first after him, who attempted to fix geography on the base of science was Marinus, of Tyre, who lived a short time before Ptolemy; of his work we have only extracts given by this geographer. He divided the terms latitude and longitude, which, as we have already stated, were introduced by Artemidorus (A.C. 104) into degrees, and these degrees into their parts, though this improvement was not reduced generally to practice before Ptolemy, for we are informed by him, that Marinus had the latitude of some places and the longitude of others, but scarcely one position where he could ascertain both.

With regard to the extent of Marinus' geographical knowledge, or the accuracy of his details, we cannot form a fair judgment from the fragments of his works which remain. According to Ptolemy, he had examined the history of preceding ages, and all the information that had been collected in his own time, comparing and rectifying them as he proceeded in his own account.

It will be recollected that the Periplus of the Erythrean Sea did not trace the African coast lower down than Rhapta; but Marinus mentions Prasum, which, according to that hypothesis, which fixes it in the lowest southern latitude, must have been seven degrees to the south of Rhapta. So far, therefore, the knowlege of the ancients, in the time of Marinus, respecting the east coast of Africa extended; but, as neither he nor Ptolemy mentions a single place between Rhapta and Prasum, it is probable that the latter was not frequently or regularly visited for the purposes of trade, but that commercial voyages were still confined to the limit of Rhapta. We have just stated that Prasum, according to the most moderate hypothesis, must be fixed seven degrees to the south of Rhapta. Marinus, however, fixes it either in thirty-five degrees south, or under the tropic of Capricorn. He was led into this and similar errors by assigning too great a number of stadia to the degree. Ptolemy endeavours to correct him, and places Prasum in latitude 15, 30 south; it is remarkable that the Prasum of Ptolemy is precisely at Mosambique, the last of the Arabian settlements in the following ages, and the Prasum of Marinus, if under the tropic of Capricorn, is the limit of the knowledge of the Arabians on this coast of Africa.

Marinus, as quoted by Ptolemy, affirms that he was in possession of the journals of two expeditions under the command of Septimus Flaccus and Julius Maternus: the former of these officers set off from Cyrene, and the latter from Leptis; and, according to Marinus, they penetrated through the interior of Africa to the southward of the Equator, as far as a nation they styled Agesymba. The error of Marinus with respect to the valuation of the stadium, has led him to fix this nation in twenty-four degrees south latitude; if allowance, however, be made for his error, the Agesymba will still be placed under the Equator,--a great distance for a land expedition to have readied in the interior of Africa. Flaccus reported that the Ethiopians of Agesymba, were three months journeying to the south of the Garamantes, and the latter were 5400 of the stadia of Marinus, distant from Cyrene. According to the journal of Maternus, when the king of the Garamantes set off to attack the people of Agesymba, he marched four months to the south.

There are also some notices in Marinus of voyages performed along the coast of Africa, between India and Africa, and along part of the coast of India; he particularly mentions one Theophilus who frequented the coast of Azania, and who was carried by a south-west wind from Rhapta to Aromata in twenty days; and Diogenes, one of the traders to India, who on his return after he had come in sight of Aromata, was caught by the north-east monsoon, and carried down the coast during twenty-five days, till he reached the lakes from which the Nile issues. Marinus also mentions a Diogenes Samius, who describes the course held by vessels from the Indus to the coast of Cambay, and from Arabia to the coast of Africa. According to him, in the former voyage they sailed with the Bull in the middle of the heavens, and the Pleiades in the middle of the main yard; in the latter voyage, they sailed to the south, and by the star Canobus.

We now arrive at the name of Ptolemy, certainly the most celebrated geographer of antiquity. He was a native of Alexandria, and flourished in the reign of the emperor Marcus Antoninus. In the application of astronomy to geography, he followed Hipparchus principally, and he seems from his residence at Alexandria to have derived much information through the merchants and navigators of that city, as well as from its magnificent and valuable library. His great work, as it has reached us, consists almost entirely of an elementary picture of the earth, (if it may be so called,) in which its figure and size, and the position of places are determined. There is only a short notice of the division of countries, and it is very seldom that any historical notice is added. To this outline, it is supposed that Ptolemy had added a detailed account of the countries then known, which is lost.

His geography, such as we have described it, consists of eight books, and is certainly much more scientific than any which had been previously written on this science. In it there appears, for the first time, an application of geometrical principles to the construction of maps: the different projections of the sphere, and a distribution of the several places on the earth, according to their latitude and longitude. Geography was thus established on its proper principles, and intimately connected with astronomical observations and mathematical science. The utility and merit of Ptolemy's work seems to have been understood and acknowledged soon after it appeared. Agathemidorus, who lived not long after him, praises him for having reduced geography to a regular system; and adds, that he treats of every thing relating to it, not carelessly, or merely according to the ideas of his own, but to what had been delivered by more ancient authors, adopting from them whatever he found consonant to truth. Agathodæmon, an artist of Alexandria, observing the request in which his work was held, prepared a set of maps to illustrate it, in which all the places mentioned in it were laid down, with the latitudes and longitudes he assigned them. The reputation of his geography remained unshaken and undiminished during the middle ages, both in Arabia and Europe; and even now, the scientific language which he first employed, is constantly used, and the position of places ascertained by specifying their latitude and longitude.

It was not to be expected, however, that Ptolemy could accurately fix the longitude and latitude of places in the remoter parts of the then known world; his latitudes and longitudes are accordingly frequently erroneous, but especially the latter. This arose partly from his taking five hundred stadia for a degree of a great circle, and partly from the vague method of calculating distances, by the estimate of travellers and merchants, and the number of days employed in their journies by land, and voyages by sea. As he took seven hundred stadia for a degree of latitude, his errors in latitude are not so important; and though the latitude he assigns to particular places is incorrect, yet the length of the globe, according to him, or the distance from the extreme points north and south, then known, is not far from the truth. Thus the latitude of Thule, according to Ptolemy, is 64 degrees north, and the parallel through the cinnamon country 16° 24' south, that is, 80° 24' on the whole, a difference from the truth of not more than six or seven degrees. It is remarked by D'Anville, and Dr. Vincent coincides in the justice of the remark, that the grandest mistake in the geography of Ptolemy has led to the greatest discovery of modern times. Strabo had affirmed, that nothing obstructed the passage from Spain to India by a westerly course, but the immensity of the Atlantic ocean; but, according to Ptolemy's errors in longitude, this ocean was lessened by sixty degrees; and as all the Portuguese navigators were acquainted with his work, as soon as it was resolved to attempt a passage to India, the difficulty was, in their idea, lessened by sixty degrees; and when Columbus sailed from Spain, he calculated on sixty degrees less than the real distance from that country to India. Thus, to repeat the observation of D'Anville, the greatest of his errors proved eventually the efficient cause of the greatest discovery of the moderns.

Beside the peculiar merit of Ptolemy, which was perceived and acknowledged as soon as his work appeared, he possesses another excellence, which, as far as we know, was first pointed out and dwelt upon by Dr. Vincent. According to him, Ptolemy, in his description of India, serves as the point of connection between the Macedonian orthography and the Sanscrit, dispersing light on both sides, and showing himself like a luminary in the centre. He seems indeed to have obtained the native appellations of the places in India, in a wonderful manner; and thus, by recording names which cannot be mistaken, he affords the means of ascertaining the country, even though he gives no particulars regarding it. We have applied this remark to India exclusively, but it might be extended to almost all the names of places that occur in Ptolemy, though, as respects India, his obtaining the native appellations is more striking and useful.

Having offered these general remarks on the excellencies and errors of Ptolemy, we shall next proceed to give a short and rapid sketch of his geographical knowledge respecting Europe, Asia, and Africa. On the north-east of Europe he gives an accurate description of the course of the Wolga; and further to the south, he lays down the course of the Tanais, much nearer what it really is than the course assigned it by Strabo. He seems to have been acquainted with the southern shores of the Baltic from the western Dwina, or the Vistula, to the Cimbric Chersonesus: he also describes part of the present Livonia. The Chersonesus, however, he stretches two degrees too far to the north, and also gives it too great a bend to the east. He applies the name of Thule to a country situated to the north-east of Britain; if his usual error in longitude is rectified, the position he assigns Thule would correspond with that of Norway. Such seem to have been the limits of his Europe, unless, perhaps, he had some vague idea of the south of Sweden.

He begins his geographical tables with the British isles; and here is one of his greatest errors. According to him, the north part of Britain stretches to the east, instead of to the north: the Mull of Galloway is the most northern promontory, and the land from it bends due east. The Western Islands run east and west, along the north shore of Ireland, the west being the true north point in them. He is, however, on the whole, pretty accurate in his location of the tribes which at that period inhabited Scotland. Strabo had placed Ireland to the north of Britain, but in its true latitude. Ptolemy's map, which is the first geographical document of that island, represents it to the west of Britain, but five degrees further to the north than it actually is. He delineates its general shape, rivers, and promontories with tolerable accuracy, and some of his towns may be traced in their present appellations, as Dublin in Eblana. It has already been noticed that he was probably acquainted with the south of Sweden, and his four Scandinavian islands are evidently Zealand, Funen, Laland, and Falster. It is remarkable that his geography is more accurate almost in proportion as it recedes from the Mediterranean. The form which he assigns to Italy is much farther removed from the truth than the form of most of the other European countries which he describes. His fundamental error in longitude led him to give to the Mediterranean Sea a much greater extent than it actually possesses. According to him, it occupies nearly sixty-five degrees; and it is a singular circumstance, as well as a decisive proof of the influence of his authority, as well of the slow progress of accurate and experimental geography, that his mensuration of this sea was reputed as exact till the reign of Louis XIV., when it was curtailed of nearly twenty-five degrees by observation.

The principal points in the geography of Asia, as given by Ptolemy, respect the coasts of India, the route to the Seres, and the Caspian sea. His delineation of India is equally erroneous with his delineation of the British Isles: according to him, it stretches in a right line from west to east, a little to the south of a line drawn between the Ganges and the Indus. He possessed, however, information respecting places in the farther peninsula of India, the locality of several of which, by comparing his names with the Sanscrit, may be traced with considerable certainty. He assigns to the island of Ceylon a very erroneous locality, arising from his error respecting the form of India, and likewise an extent far exceeding the truth. He is the first author, however, who mentions the seven mouths of the Ganges. The route to the Seres, which he describes, has been already noticed: it is remarkable that the latitude which he assigns to his Sera metropolis, is within little more than a degree of the latitude of Pekin, which, in the opinion of Dr. Vincent, is one of the most illustrious approximations to truth that ancient geography affords. His description of Arabia is, on the whole, accurate; he has, however, greatly diminished the extent of the Arabian Gulf, and by at the same time increasing the size of the Persian, he has necessarily given an erroneous form to this part of Asia. The ancient opinion of Herodotus, that the Caspian was a sea by itself, unconnected with any other, which was overlooked or disbelieved by Strabo, Arrian, &c. was adopted by Ptolemy, but he erroneously describes it as if its greatest length was from east to west. The peninsula to which he gives the name of the Golden Chersonesus, and which is probably Malacca, he describes as stretching from north to south: to the east of it he places a great bay, and in the most distant part of it the station of Catigara. Beyond this, he asserts that the earth is utterly unknown, and that the land bends from this to the west, till it joins the promontory of Prasum in Africa, at which place this quarter of the world terminated to the south. Hence it appears that he did not admit a communication between the Indian and Atlantic oceans, and that he believed the Erythrean sea to be a vast basin, entirely enclosed by the land.

Strabo and Pliny believed that Africa terminated under the torrid zone, and that the Atlantic and Indian oceans joined. Ptolemy, as we have just seen, rejected this idea, and following the opinion of Hipparchus, that the earth was not surrounded by the ocean, but that the ocean was divided into large basins, separated from each other by intervening land, maintained, that while the eastern coast of Africa at Cape Prasum united with the coast of Asia at the bay of the Golden Chersonesus, the western coast of Africa, after forming a great gulf, which he named Hespericus, extended between the east and south till it joined India. The promontory of Prasum was undoubtedly the limit of Ptolemy's knowledge of the east coast of Africa: the limit of his knowledge of the west coast is not so easily fixed: some suppose that it did not reach beyond the river Nun; while others, with more reason, extend it to the Gulf of St. Cyprian, because the Fortunate Islands, which he assumed as his first meridian, will carry his knowledge beyond the Nun; and because, at the Gulf of St. Cyprian, the coast turns suddenly and abruptly to the east, in such a manner as may be supposed to have led Ptolemy to believe that it stretched towards and joined the coast of India.

Of some of the interior parts of Africa Ptolemy possessed clear and accurate information; regarding others, he presents us with a mass of confused notions. He clearly points out the Niger, though he fixes its source in a wrong latitude. In the cities of Tucabath and Tagana, which he places on its banks, may perhaps be recognized Tombuctoo and Gana. The most striking defect in his geography of the interior of Africa is, that he does not allow sufficient extent to the great desert of Sahara, while the southern parts are too much expanded. He places the sources of the Nile, and the Mountains of the Moon in south latitude thirteen, instead of north latitude six or seven; but the error of latitude is not so remarkable and unaccountable as the very erroneous latitude which he assigns to Cape Aromata, on a coast which was visited every year by merchants he must have seen at Alexandria. The most difficult point to explain in Ptolemy's central Africa is the river Gir, which he describes as equal in length to the Niger, and running in the same direction, till it loses itself in the same lake. What this river is, geographers have not agreed. It is mentioned by Claudian, as resembling the Nile in the abundance of its waters. Agethimedorus, a geographer of the third century, regards it and the Niger as the same river.

What then was the amount of the knowledge of the ancients, as it existed among the Romans, in the height of their power, respecting the form, extent, and surface of the globe? If we view a map drawn up according to their ideas, we are immediately struck with the form they assigned the world, and perceive with what propriety they called the extent of the world from east to west longitude or _length_, and the extent from north to south latitude, or _breadth_. In some maps, especially that drawn up from the celebrated Peutingerian Tables, which contain an itinerary of the whole Roman empire, thirty-five degrees of longitude occupy twenty-eight feet eight inches, whereas thirteen degrees of latitude are compressed within the space of one foot. It is easy to conceive how it happened that too much space is assigned between places situated east and west of each other, as the latitude of a place is much more easily determined than its longitude. At the same time, as the routes of the Roman armies generally were from east to west, the countries lying in that direction were better known than those lying to the north and south, though the longitudes, and general space assigned the world, in the former deviation, were erroneous. It was the opinion of most of the ancient geographers, that there was a southern continent or hemisphere, to correspond to and balance the northern; and this they formed by cutting off the great triangle to the south. The ancients also, while they curtailed those parts of the world with which they were unacquainted, extended the known parts.

The limit of the Roman geography of Europe to the north was the Baltic, beyond which they had some very imperfect and obscure notion of the south of Sweden, and perhaps of Norway. They were acquainted with the countries on the eastern boundary of Europe lying on the Danube and the Vistula, and the rivers Wolga and Tanais seem also to have been tolerably well known to them. Of the whole of the west of Europe they were well informed, with the exception of the general figure, and some part of the British isles.

With respect to Africa, the Romans seem to have been acquainted with one-third of it. The promontory of Prasum was the limit of their knowledge on the east coast: its limits on the western coast it is not so easy to fix. The western horn was the limit of the voyage of Hanno, which, according to some, is Cape Nun; and, according to others, Cape Three Points, in Guinea; and we have observed already, that the Gulf of St. Cyprian was probably the limit of Ptolemy's knowledge. The coasts of Africa on the Mediterranean, and on the Red Sea, were of course well known to the Romans; and some points of their information respecting the interior were clear and accurate, but, as for these, they trusted almost entirely to the reports of merchants, they were as frequently erroneous.

The northern, north-western, north-eastern, and east parts of Asia were almost utterly unknown to the Romans; but they possessed tolerably accurate information regarding the whole hither peninsula of India, from the Indus to the Ganges, and some partial and unconnected notices of the farther peninsula and of China.

[5] The most probable opinion is, that they were made of fluat of
lime, or Derbyshire spar.