Volume Xviii Part 4 (2/2)

The erection of the tower of Pharos was by no means the only service the first Ptolemy did to commerce; throughout all his reign he manifested great attention to it and maritime affairs, as well as to those sciences by which they might be improved and advanced. As soon as he had made himself master of Palestine, Syria, and Phoenicia, he turned his thoughts to the conquest of Cyprus: this island abounded in wood, of which Egypt was almost dest.i.tute; and on this account, as well as on account of its situation, in the bosom, as it were, of the Levant, it was of the utmost importance to a maritime power. He succeeded in obtaining possession of this valuable island, and thus improved and enlarged the commercial advantages of Egypt.

His next step, with this view, was to invite the sailors of Phoenicia to his new capital. His increasing power, especially at sea, roused the envy of Antigonus, who, by extraordinary exertions, in the course of twelve months built and equipped a fleet, which was able to cope with the naval power of Ptolemy. It is foreign to our purpose to notice the wars between them, except in so far as they are connected with the commercial history of Alexandria. This city was benefited by these wars, for Antigonus, in his progress, had driven many of the inhabitants of Syria, Palestine, and Phoenicia from their native lands: to these Ptolemy gave great encouragement, and extraordinary privileges and immunities, which induced them to settle in Alexandria, where they followed their mercantile or commercial pursuits. The report of these advantages granted to foreigners, led Jews, Greeks and Macedonians to flock to Egypt, by which means the population and wealth of that country, and particularly of its capital, were greatly augmented.

The foundation of the museum and library of Alexandria, both of which contributed so essentially to science and to the establishment of the Alexandrian school of philosophy, which, as we shall afterwards perceive, produced men that greatly advanced geographical knowledge, is another proof of the wise and comprehensive character of Ptolemy's mind.

But Ptolemy rather prepared the way for the advancement of commerce and maritime discovery, than contributed directly to them himself: fortunately, his son, Ptolemy Philadelphus, was a worthy successor, and emulous of treading in his father's steps. About the beginning of his reign, Tyre, the ancient station of the trade with India, again reared its head as a commercial city, and engaged extensively and successfully in this lucrative traffic. It became necessary, therefore, in order to draw it from Tyre and to secure its centering in Alexandria, to extend the facilities and advantages of this city for this traffic. With this view, Ptolemy sent travellers to penetrate into the interior of his dominions, bordering on the Red Sea, by land, while his fleet was exploring the coast: he began to make a ca.n.a.l, 100 cubits broad and 30 deep, between Arsinoe on the Red Sea, and the eastern branch of the Nile, in order to complete a water-communication between India and Alexandria. This ca.n.a.l, however, was never completed; probably on account of the tedious and difficult navigation towards the northern extremity of the Red Sea. He therefore altered his plan, and instead of Arsinoe fixed on Myos Hormos, as the port from which the navigation to India should commence. The same reason which induced him to form this port; led him afterwards to the establishment of Berenice; he was farther led to this, as Berenice was lower down in the Red Sea, and consequently s.h.i.+ps sailing from it reached the ocean sooner and with less difficulty. It appears, however, that till the Romans conquered Egypt, the greatest portion of the trade between Alexandria and [Egypt->India] was carried on through Myos Hormos. The route in the time of Ptolemy and his successors was as follows: vessels pa.s.sed up the Canopic branch of the Nile to Memphis, and thence to Coptus; from Coptus the goods were transported in caravans to Myos Hormos: from this port the vessels sailed for Africa, or Arabia in the month of September, and for India in July. As the country over which the caravans travelled was the desart of Thebais, which is almost dest.i.tute of water, Ptolemy ordered springs to be searched for, wells to be dug, and caravanseras to be erected.

In order to protect his merchant s.h.i.+ps in the Mediterranean and the Red Sea, he fitted out two great fleets, one of which he constantly kept in each sea. That in the Mediterranean was very numerous, and had several s.h.i.+ps of an extraordinary size: two of them in particular had 30 oars on a side, one 20, four 14, two 12, fourteen 11, thirty 9, &c., besides a great number of vessels of four oars and three oars on a side. With these fleets he protected the commerce of his subjects, and kept in subjection most of the maritime provinces of Asia Minor; viz. Cilicia, Pamphylia, Lycia and Caria. The names of some of the most celebrated geographers who were patronized by this monarch, have been handed down to us: Pliny mentions Dalion, Bion, Boselis, and Aristocreon, as having visited Ethiopia, and contributed to the geographical knowledge of that country; and Simonides as having resided five years at Meroe. Timosthenes lived in this reign: he published a description of the known sea-ports, and a work on the measure of the earth. He sailed down the coast of Africa, probably as far as Madagascar, certainly lower down than the Egyptians traded under the Ptolemies, or even under the Romans.

The reign of Ptolemy Euergetes was equally distinguished, with, those of his predecessors, by attention to commerce, and a desire to extend it. As the navigation of the Red Sea had now become a source of great wealth to his subjects, he deemed it necessary to free it as much as possible from the pirates that infested it's coasts; for this purpose, as well as to preserve a communication between Egypt and the countries which extended to its mouth, he established governors from the isthmus of Suez, along the Arabian and African coasts, as far as the straits of Babelmandeb; and planted colonies of Greeks and Egyptians to carry on the commerce, and protect the interests of his subjects. But the most extraordinary instance of his enterprising spirit is to be found in his conquest (evidently for the purpose of facilitating and securing the commerce of the Red Sea) of part of Abyssinia. The proof of this, indeed, rests entirely on an inscription found at Aduli, which there can be no doubt is the harbour and bay of Masuah; the only proper entrance, according to Bruce, into Abyssinia. The inscription to which we have alluded was extant in the time of Cosmas (A.D. 545), by whom it was seen. From it, Ptolemy appears to have pa.s.sed to the Tacazze, which he calls the Nile, and to have penetrated into Gojam, in which province the fountains of the Nile are found. He made roads, opened a communication between this country and Egypt, and during this expedition obliged the Arabians to pay tribute, and to maintain the roads free from robbers and the sea from pirates; subduing the whole coast from [Leucke->Leuke] Come to Sabea. The inscription adds: ”In the accomplishment of this business I had no example to follow, either of the ancient kings of Egypt, or of my own family; but was the first to conceive the design, and to carry it into execution. Thus, having reduced the whole world to peace under my own authority, I came down to Aduli, and sacrificed to Jupiter, to Mars, and to Neptune, imploring his protection for all who navigate these seas.”

Ptolemy Euergetes was particularly attentive to the interests of the library at Alexandria. The first librarian appointed by Ptolemy the successor of Alexander, was Zenodotus; on his death, Ptolemy Euergetes invited from Athens Eratosthenes, a citizen of Cyrene, and entrusted to him the care of the library: it has been supposed that he was the second of that name, or of an inferior rank in learning and science, because he is sometimes called Beta; but by this appellation nothing else was meant, but that he was the second librarian of the royal library at Alexandria. He died at the age of 81, A.C. 194. He has been called a second Plato, the cosmographer and the geometer of the world: he is rather an astronomer and mathematician than a geographer, though geography is indebted to him for some improvements in its details, and more especially for helping to raise it to the accuracy and dignity of a science. By means of instruments, which Ptolemy erected in the museum at Alexandria, he ascertained the obliquity of the ecliptic to be 23 51' 20”. He is, however, princ.i.p.ally celebrated as the first astronomer who measured a degree of a great circle, and thus approximated towards the real diameter of the earth.

The importance of this discovery will justify us in entering on some details respecting the means which this philosopher employed, and the result which he obtained.

It is uncertain whether the well at Syene, in Upper Egypt, which he used for this purpose, was dug by his directions, or existed previously. Pliny seems to be of the former opinion; but there is reason to believe that it had a much higher antiquity. The following observations on its structure by Dr. Horsley, Bishop of Rochester, are ingenious and important. ”The well, besides that it was sunk perpendicularly, with the greatest accuracy, was, I suppose, in shape an exact cylinder. Its breadth must have been moderate, so that a person, standing upon the brink, might safely stoop enough over it to bring his eye into the axis of the cylinder, where it would be perpendicularly over the centre of the circular surface of the water. The water must have stood at a moderate, height below the mouth of the well, far enough below the mouth to be sheltered from the action of the wind, that its surface might be perfectly smooth and motionless; and not so low, but that the whole of its circular surface might be distinctly seen by the observer on the brink. A well formed in this manner would afford, as I apprehend, the most certain observation of the sun's appulse to the zenith, that could be made with the naked eye; for when the sun's centre was upon the zenith, his disc would be seen by reflection on the water, in the very middle of the well,--that is, as a circle perfectly concentric with the circle of the water; and, I believe, there is nothing of which the naked eye can judge with so much precision as the concentricity of two circles, provided the circles be neither very nearly equal, nor the inner circle very small in proportion to the outer.”

Eratosthenes observed, that at the time of the summer solstice this well was completely illuminated by the sun, and hence he inferred that the sun was, at that time, in the zenith of this place. His next object was to ascertain the alt.i.tude of the sun, at the same solstice, and on the very same day, at Alexandria. This he effected by a very simple contrivance: he employed a concave hemisphere, with a vertical style, equal to the radius of concavity; and by means of this he ascertained that the arch, intercepted between the bottom of the style and the extreme point of its shadow, was 7 12'. This, of course, indicated the distance of the sun from the zenith of Alexandria. But 7 12' is equal to the fiftieth part of a great circle; and this, therefore, was the measure of the celestial arc contained between the zeniths of Syene and Alexandria. The measured distance between these cities being 5000 stadia, it followed, that 5000 X 50 = 250,000, was, according to the observations of Eratosthenes, the extent of the whole circ.u.mference of the earth.

If we knew exactly the length of the stadium of the ancients, or, to speak more accurately, what stadium is referred to in the accounts which have been transmitted to us of the result of the operations of Eratosthenes, (for the ancients employed different stadia,) we should be able precisely to ascertain the circ.u.mference which this philosopher ascribed to the earth, and also, whether a nearer approximation to the truth was made by any subsequent or prior ancient philosopher. The circ.u.mference of the earth was conjectured, or ascertained, by Aristotle, Cleomedes, Posidonius, and Ptolemy respectively, to be 400, 300, 240, and 180 thousand stadia. It is immediately apparent that these various measures have some relation to each other, and probably express the same extent; measured in different stadia; and this probability is greatly increased by comparing the real distances of several places with the ancient itinerary distances.

The observation of Eratosthenes respecting the obliquity of the ecliptic (though undoubtedly not so immediately or essentially connected with our subject as his observation of the circ.u.mference of the earth) is too important to be pa.s.sed over entirely without notice. He found the distance between the tropics less than 53 6', and greater than 52 96', which gives a mean of 23 51' for the obliquity of the ecliptic. The observations of Hipparchus (who flourished at Alexandria about 140 years before Christ, and whom we shall have occasion to mention more particularly afterwards) coincided with those of Eratosthenes. Plutarch, however, who died A.D. 119, informs us, that, in his time, the gnomons at Syene were no longer shadowless on the day of the summer solstice. As the interval between Eratosthenes and Plutarch was only about 512 years, Bishop Morsley has very naturally expressed his doubts of the accuracy of Plutarch's a.s.sertion. He says, that the change in the obliquity of the ecliptic in this interval was only 2' 36”. ”A gnomon, therefore, at Syene, of the length of twelve inches, if it cast no shadow on the day of the solstice in the time of Eratosthenes, should have cast a shadow in the time of Plutarch of the length only of 9/1000th, or not quite 1/100th part of an inch. The shadow of a perpendicular column of the height of 100 feet would have been 9/10ths of an inch.” As, however, the ancients do not appear to have constructed gnomons of such a size, and as gnomons of inferior size would have given a shadow scarcely perceptible, it is probable that Plutarch is mistaken in his a.s.sertion; or, at any rate, that the very small variation which did take place between his time and that of Eratosthenes (if it were observed at all) was ascertained by means of the well itself, which would point it out much more distinctly and accurately than any gnomon the ancients can be supposed to have used.

We are also indebted to Eratosthenes for the first regular parallel of lat.i.tude, and also for tracing a meridian. His parallel of lat.i.tude began at the Straits of Gibraltar, and pa.s.sed eastward through Rhodes to the mountains of India; the intermediate places being carefully set down. His meridian line pa.s.sed through Rhodes and Alexandria, as far as Syene and Meroe. Meroe, on this account, became an object of the greatest interest and importance to all the succeeding ancient geographers and astronomers, and they have taken the utmost labour and care to ascertain its lat.i.tude accurately. Strabo informs us, that Eratosthenes constructed a map of the world; but he does not give such particulars as will enable us to trace the extent of his geographical knowledge. At the extremity of the world to the east, bounded by the ocean, Thina was placed in the map of Eratosthenes, in the parallel of Rhodes; a parallel which pa.s.ses through the empire of China, within the Great Wall. Eratosthenes, according to Strabo, (to whom we are indebted for nearly all we know respecting this philosopher,) a.s.serts that Thina had been, previously to the construction of his map, incorrectly placed in the more ancient maps. His information respecting Meroe or Abyssinia, is most probably derived from Dalion, Aristocreon, and Bion, who had been sent by Ptolemy Philadelphus and his successors into that country, or from Timosthenes, who sailed down the coast of Africa as low as Cerne. His information on the subject of India (which, however, as far as regards oriental commerce, is very confused) must have been derived from the Macedonians. There is little doubt that the library of Alexandria afforded him access to all the knowledge which then existed respecting the various countries of the globe; but the turn of his mind led him rather to astronomical than geographical studies; or rather, perhaps, he directed his labours and his talents to the discovery of the figure and circ.u.mference of the earth, thinking, that till this was effected, the delineation of the habitable world, and the relative position of different countries, must be very inaccurate as well as incomplete. This opinion regarding Eratosthenes, that he was more of a geometrician than a geographer, seems to be confirmed by the testimony of Marcian of Heraclia, who informs us, that Eratosthenes took the whole work of Timosthenes, preface and all, as it stood, and in the very same words. If this account be accurate, it is probable that Eratosthenes' knowledge of Thina, and his being able to correct the erroneous position of this country in more ancient maps, was derived from Timosthenes, who had commanded the fleet of Ptolemy Philadelphus on the Indian Ocean.

If we reflect on the rude and imperfect state of science at this period, the paucity and inadequacy of the instruments by means of which it might be improved, and the superst.i.tions and prejudices which opposed the removal of error or the establishment of truth, we shall not be disposed to question the justice of the panegyric p.r.o.nounced by Pliny on Eratosthenes. This author, after detailing all that was then known on the subject of the circ.u.mference of the earth, and on the distances which had been ascertained by actual admeasurement, or approximated by a.n.a.logy or probable conjecture, between the most remarkable places on its surface, adds, that Eratosthenes, whose acuteness and application had advanced him far in every branch of knowledge, but who had outstripped all his predecessors or contemporaries in that particular branch which was connected with the admeasurement of the earth, had fixed its circ.u.mference at 250,000 stadia; a bold and almost presumptuous enterprize, (_improb.u.m ausum_,) but which had been conducted with so much judgment, and on such sound principles, that it commanded and deserved our credit. Hipparchus, who was distinguished for his correctness and diligence in every part of geometrical and astronomical science, and who had specially exerted those qualities in his endeavours to correct the errors of Eratosthenes, had been able to add only the comparatively small extent of 25,000 stadia to the computation of Eratosthenes.--_Plin. Nat.

Hist._ lib. ii. c. 108.

Eratosthenes seems, from the nature of his studies, not to have availed himself so much as he might have done of the treasures contained in the Alexandrian library under his care, to correct or extend the geographical knowledge of his contemporaries. The same observation will not apply to Agatharcides, who was president of the library after Eratosthenes. The exact time at which he flourished is not known: according to Blair, he was contemporary with Eratosthenes, though younger than him, and flourished 177 A.C., Eratosthenes having died at the age of eighty-one, in the year 194 A.C. Dodwell, however, fixes him at a later period; viz. 104 A.C.; but this date must be erroneous, because Artemidorus of Ephesus, who evidently copies Agatharcides, undoubtedly lived 104 A.C. Agatharcide's was born at Cnidus in Caria: no particulars are known respecting him, except that he was president of the Alexandrian library, in the reign of Ptolemy Philometor, if he flourished 177 A.C.; and in the reign of Ptolemy Lathyrus, if, according to Dodwell, he did not flourish till 104 A.C.

The only work of his which is preserved, is a Treatise on the Erythraean Sea; and this we possess only in the Bibliotheca of Photius, and incorporated in the history of Diodorus Siculus. The authority of Agatharcides was very high among the ancients. Strabo, Pliny, and Diodorus, always mention him with the utmost respect, and place implicit confidence in his details. Diodorus expressly states that Agatharcides and Artemidorus (who, as we have already mentioned, was merely his copyist) are the only authors who have written truth concerning Egypt and Ethiopia; and Strabo follows him in all that relates to the latter country, the countries lying to the south of Egypt, and the western coast of Arabia. In fact, for nearly 200 years, the ancient historians and geographers drew all the information they possessed respecting the portions of the world embraced in the work of Agatharcides from that work. It has been well observed, ”that when Pliny speaks of the discoveries on the coast of Malabar in his own age, and adds, that the names he mentions are new, and not to be found in previous writers, we ought to consider him as speaking of all those who had followed the authority of the Macedonians, or the school of Alexandria; of which, in this branch of science, Eratosthenes and Agatharcides were the leaders.”

From the circ.u.mstance that Strabo appeals very frequently to the authority of Eratosthenes, in conjunction with that of Agatharcides, it has been conjectured, that the work of the latter contains all that the former knew, with the addition of his own information; and this conjecture is highly probable, considering that Agatharcides had access to the sources whence Eratosthenes drew his information; to the works of Eratosthenes themselves, which of course would be deposited in the Alexandrian library; and to all the additional works which had enriched the library from the time of Eratosthenes, as well as the additional information which the extensive commerce of Alexandria would supply.

The work of Agatharcides, therefore, having been in such estimation by the ancient historians and geographers, and the only source from which, during 200 years, they drew their information, and having been compiled by a person, who, it is probable, had better and fuller means of rendering it accurate and complete than any of his contemporaries enjoyed; it will be proper to give a pretty full abstract of the most interesting and important part of its contents.

The veracity of this author was questioned by Plutarch, from his narrating a circ.u.mstance, which, to us of the present day, is a strong confirmation of the truth and accuracy of his information. Agatharcides takes notice of the worm which is formed in the legs, and which insinuates itself there in such a manner, that it is necessary to wind it out with the utmost caution.

Plutarch ridicules and rejects this story, and says it never has happened, and never will. But that such a worm exists, and that when it insinuates itself into the leg it must be drawn out with the utmost caution, lest the smallest portion of it remain, and thus produce disease, is directly and fully attested by all the travellers, and particularly by Bruce, who carried with him to the grave the marks and effects of the attack of this species of worm.

But the most curious and important portion of the work of Agatharcides on the Red Sea, relates to Abyssinia; for in this work we meet with the first genuine characteristics of this nation. He specifies particularly the gold mines wrought by the kings of Egypt on the coast of the Red Sea;--the process which they followed to procure and separate this metal;--the sufferings which the miners underwent in their operations are painted in very strong language: ”The mult.i.tude of bones still found in these excavations, he says, is incredible, of wretches crushed by the falling-in of the earth, as must naturally happen in a loose and crumbling soil.” He adds a circ.u.mstance, to which there are many parallel in our own country, in those mines which are supposed to have been wrought by the Romans; viz.

the tools of copper found in these gold mines, supposed to have been used by the native Egyptians, prior to the conquest of Egypt by the Persians.

The next particular mentioned by Agatharcides, respecting the Abyssinian coast of the Red Sea, is very conclusive, with respect to his accuracy and credibility. In Meroe, or Abyssinia, he says, they hunt elephants and hamstring them, and afterwards cut the flesh out of the animal alive: he adds, that the inhabitants are so extremely fond of the flesh of the elephant, thus procured, that when Ptolemy would have paid any price to purchase these animals alive, as he wanted them for his army, the Abyssinian hunters refused his offer, declaring that not all the wealth of Egypt would tempt them to forego their favourite and delicious repast. It is a remarkable fact, that the credit of Bruce on this topic should thus be confirmed by a writer who lived nearly 2000 years before him, of whose writings we possess only a very short treatise, and of whose life we know scarcely a single particular. It may be added, that Strabo, in a pa.s.sage, in which he is apparently copying Agatharcides, mentions [Greek: Kreophagoi] and as he would scarcely particularize the fact of a native eating the flesh of animals cooked, it is to be presumed, he means raw flesh. In the same place he mentions the _excisio feminarum_.

Every reader of Brace's Travels in Abyssinia must remember the fly, called Tsalpsalza, an insect more formidable than the strongest or most savage wild beasts: ”As soon as the buzzing of this insect is heard, the utmost alarm and trepidation prevails; the cattle forsake their food and run wildly about the plain, till at length they fall down, worn out with terror, hunger and fatigue; even the camel, elephant and rhinoceros, are not safe from the attacks of this formidable insect.” This fly is described by Agatharcides in the same manner as by Bruce. The ensete tree of Bruce, the leaves of which resemble the banana, with fruit like figs, but not eatable, with a trunk esculent till it reaches its perfect growth and is full of leaves, resembles in some of its particulars a tree described by Agatharcides. This author also describes the locusts, as generally used for food; the troglodytes; the rhinoceros; the cameleopard; what he calls sphinxes, but which are represented as tame, and are supposed to be apes, distinguished from the common ape in the face being smooth and without hair. He also mentions an animal he calls crocetta, which is described as being between a wolf and a dog, and as imitating the human voice; these particulars seem to point it out as the hyena, though some suppose it to be the jackall. It deserves to be remarked, that the animals enumerated by Agatharcides as natives of Abyssinia, are all named in the same manner, as well as depicted on the celebrated Palestrine Mosaic.

In his description of the coast of the Red Sea he commences with Arsinoe, and goes down the western side as far as Ptolemais Theron; a place so called, because elephants were there hunted and taken, and are still, according to Bruce. Agatharcides adds, that the usual navigation was to this place for elephants. He notices Myos Hormos, but not Berenice; he has even mentioned the islands at the straits of Babelmandeb, and the prodigies which in his time, and much later, were supposed to lie beyond them. There is, however, one part of his work, in which he seems to indicate the curvature of the African coast to the east beyond the straits; but it is doubtful whether in this place he is speaking of the coast within or without the straits.

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