Page:The Natural History of Pliny.djvu/447

 Chap. 10.] ACCOITKT OF COTTNTEIES, ETC. 413 either that its waters are driven back by the Etesian winds which are blowing at this season of the year from an oppo- site direction, and that the sea which lies beyond is driven into the mouths of the river ; or else that its waters are swollen bv the summer rains of ^Ethiopia^, wnich fall from the clouds conveyed thither by the Etesian winds from other parts of the earth. Tim«us the mathematician has alleged a reason of an occult nature : he says that the source of the river is known by the name of Phiala, and that the stream buries itself in channels underground, where it sends forth vapoms generated by the heat among the steaming rocks amid which it conceals itself; but that, during the days of the inundation, in consequence of the sun approaching nearer to the earth, the waters are drawn forth by the influence of his heat, and on being thus exposed to the air, overflow ; after which, in order that it may not be utterly di'ied up, the stream hides itself once more. He says that this takes place at the rising of the Dog-Star, when the sun enters the sign of Leo, and stands in a vertical position over the source of the river, at which time at that spot there is no shadow throwai. Most authors, however, are of opinion, on the contrary, that the river flows in greater volume when the sun takes his departure for the north, which he does when he enters the signs of Cancer and Leo, because its waters then are not dried up to so great an extent ; while on the other hand, wlien he returns towards the south pole and re-enters Capricorn, its waters are absorbed by the heat, and consequently flow in less abundance. If there is any one inclined to be of opinion, with Timseus, that the waters of the river may be drawn out of the earth by the heat, it will be as well for him to bear in mind the fact, that the absence of shadow is a phsenomenon which lasts conti- nuously^ in these regions. ^ The Etesians are periodical winds, which blow steadily from one qiiarter for forty days each year, during the season of the Dog-days. The opinion here stated was that promulgated by Thales the pliilosopher. Seneca refutes it in B. iv. c. 2. of his Qurest. Nat. 2 This was the opinion of Democritus of Abdera, and of Agathar- cliidas of Cnidos. It is combated by Diodorus Siciilus, B. i., but it is the opinion most generally received at the present day. See the disqui- sition on the subject introduced in the Ninth book of Lucan's Pharsalia. 3 And that the high tide or inundation would be cousequently con- tinuous as well.