Strabo - The Geography of Strabo (Vol.1-3)

10. Some, however, may be disinclined to admit this explanation, and would rather have proof from things more manifest to the senses, and which seem to meet us at every turn. Now deluges, earthquakes, eruptions of wind, and risings in the bed of the sea, these things cause the rising of the ocean, as sinking of the bottom causes it to become lower. It is not the case that small volcanic or other islands can be raised up from the sea, and not large ones, nor that all islands can, but not continents, since extensive sinkings of the land no less than small ones have been known; witness the yawning of those chasms which have ingulfed whole districts no less than their cities, as is said to have happened to Bura, 342Bizone, 343and many other towns at the time of earthquakes: and there is no more reason why one should rather think Sicily to have been disjoined from the mainland of Italy than cast up from the bottom of the sea by the fires of Ætna, as the Lipari and Pithecussan 344Isles have been.

11. However, so nice a fellow is Eratosthenes, that though he professes himself a mathematician, 345he rejects entirely the dictum of Archimedes, who, in his work “On Bodies in Suspension,” says that all liquids when left at rest assume a spherical form, having a centre of gravity similar to that of the earth. A dictum which is acknowledged by all who have the slightest pretensions to mathematical sagacity. He says that the Mediterranean, which, according to his own description, is one entire sea has not the same level even at points quite close to each other; and offers us the authority of engineers for this piece of folly, notwithstanding the affirmation of mathematicians that engineering is itself only one division of the mathematics. He tells us that Demetrius 346intended to cut through the Isthmus of Corinth, to open a passage for his fleet, but was prevented by his engineers, who, having taken measurements, reported that the level of the sea at the Gulf of Corinth was higher than at Cenchrea, 347so that if he cut through the isthmus, not only the coasts near Ægina, but even Ægina itself, with the neighbouring islands, would be laid completely under water, while the passage would prove of little value. According to Eratosthenes, it is this which occasions the current in straits, especially the current in the Strait of Sicily, 348where effects similar to the flow and ebb of the tide are remarked. The current there changes twice in the course of a day and night, like as in that period the tides of the sea flow and ebb twice. In the Tyrrhenian sea 349the current which is called descendent, and which runs towards the sea of Sicily, as if it followed an inclined plane, corresponds to the flow of the tide in the ocean. We may remark, that this current corresponds to the flow both in the time of its commencement and cessation. For it commences at the rising and setting of the moon, and recedes when that satellite attains its meridian, whether above [in the zenith] or below the earth [in the nadir]. In the same way occurs the opposite or ascending current, as it is called. It corresponds to the ebb of the ocean, and commences as soon as the moon has reached either zenith or nadir, and ceases the moment she reaches the point of her rising or setting. [So far Eratosthenes.]

12. The nature of the ebb and flow has been sufficiently treated of by Posidonius and Athenodorus. Concerning the flux and reflux of the currents, which also may be explained by physics, it will suffice our present purpose to observe, that in the various straits these do not resemble each other, but each strait has its own peculiar current. Were they to resemble each other, the current at the Strait of Sicily 350would not change merely twice during the day, (as Eratosthenes himself tells us it does,) and at Chalcis seven times; 351nor again that of Constantinople, which does not change at all, but runs always in one direction from the Euxine to the Propontis, and, as Hipparchus tells us, sometimes ceases altogether. However, if they did all depend on one cause, it would not be that which Eratosthenes has assigned, namely, that the various seas have different levels. The kind of inequality he supposes would not even be found in rivers only for the cataracts; and where these cataracts occur, they occasion no ebbing, but have one continued downward flow, which is caused by the inclination both of the flow and the surface; and therefore though they have no flux or reflux they do not remain still, on account of a principle of flowing which is inherent in them; at the same time they cannot be on the same level, but one must be higher and one lower than another. But who ever imagined the surface of the ocean to be on a slope, especially those who follow a system which supposes the four bodies we call elementary, to be spherical. 352For water is not like the earth, which being of a solid nature is capable of permanent depressions and risings, but by its force of gravity spreads equally over the earth, and assumes that kind of level which Archimedes has assigned it.

13. To what we cited before concerning the temple of Ammon and Egypt, Eratosthenes adds, that to judge from appearances, Mount Casius 353was formerly covered by sea, and the whole district now known as Gerra lay under shoal water touching the bay of the Erythræan Sea, 354but was left dry on the union 355of the [Mediterranean] Sea [with the ocean]. A certain amphibology lurks here under this description of the district lying under shoal water and touching the bay of the Erythræan Sea; for to touch 356both means to be close to, and also to be in actual contact with, so that when applied to water it would signify that one flows into the other. I understand him to mean, that so long as the strait by the Pillars of Hercules remained closed, these marshes covered with shoal-water extended as far as the Arabian Gulf, but on that passage being forced open, the Mediterranean, discharging itself by the strait, became lower, and the land was left dry.

On the other hand, Hipparchus understands by the term touching , that the Mediterranean, being over-full, flowed into the Erythræan Sea, and he inquires how it could happen, that as the Mediterranean flowed out by this new vent at the Pillars of Hercules, the Erythræan Sea, which was all one with it, did not flow away too, and thus become lower, but has always retained the same level? and since Eratosthenes supposes the whole exterior sea to be confluent, it follows that the Western Ocean 357and the Erythræan Sea are all one; and thus [remarks Hipparchus] as a necessary consequence, the sea beyond the Pillars of Hercules, the Erythræan Sea, and that also which is confluent with it, 358have all the same level.

14. But, Eratosthenes would reply, I never said that, in consequence of the repletion of the Mediterranean, it actually flowed into the Erythræan Sea, but only that it approached very near thereto: besides, it does not follow, that in one and the self-same sea, the level of its surface must be all the same; to instance the Mediterranean itself, no one, surely, will say it is of the same height at Lechæum 359and at Cenchrea. 360This answer Hipparchus anticipated in his Critique; and being aware of the opinion of Eratosthenes, was justified in attacking his arguments. But he ought not to have taken it for granted, that when Eratosthenes said the exterior sea was all one, he necessarily implied that its level was every where the same.

15. Hipparchus rejects as false the [account] of the inscription on the dolphins “by the delegates from Cyrene,” but the reason he assigns for this is insufficient, viz. that though Cyrene was built in times of which we have record, no one mentions the oracle, 361as being situated on the sea-shore. But what matters is that no historian has recorded this, when amongst the other proofs from which we infer that this place was formerly on the sea-shore, we number this of the dolphins which were set up, and the inscription, “by the delegates from Cyrene?” 362Hipparchus agrees that if the bottom of the sea were raised up, it would lift the water with it, and might therefore overflow the land as far as the locality of the oracle, or more than 3000 stadia from the shore; but he will not allow that the rising would be sufficient to overflow the Island of Pharos and the major portion of Egypt, since [he says] the elevation would not be sufficient to submerge these. He alleges that if before the opening of the passage at the Pillars of Hercules, the Mediterranean had been swollen to such an extent as Eratosthenes affirms, the whole of Libya, and the greater part of Europe and Asia, must long ago have been buried beneath its waves. Besides, he adds, in this case the Euxine would in certain places have been connected with the Adriatic, since in the vicinity of the Euxine, [near to its source,] 363the Ister is divided in its course, and flows into either sea, owing to the peculiarities of the ground. 364To this we object, that the Ister does not take its rise at all in the vicinity of the Euxine, but, on the contrary, beyond the mountains of the Adriatic; neither does it flow into both the seas, but into the Euxine alone, and only becomes divided just above its mouths. This latter, however, was an error into which he fell in common with many of his predecessors. They supposed that there was another river in addition to the former Ister, bearing the same name, which emptied itself into the Adriatic, and from which the country of Istria, through which it flowed, gained that appellation. It was by this river they believed Jason returned on his voyage from Colchis.