It frequently happens that in spots where forests have been felled, springs of water make[1] their appearance, the supply of which was previously expended in the nutriment of the trees. This was the case upon Mount Hæmus for example, when, during the siege by Cassander,[2] the Gauls cut down a forest for the purpose of making a rampart. Very often too, after removing the wood which has covered an elevated spot and so served to attract and consume the rains, devastating torrents are formed by the concentration of the waters. It is very important also, for the maintenance of a constant supply of water, to till the ground and keep it constantly in motion, taking care to break and loosen the callosities of the surface crust: at all events, we find it stated, that upon a city of Crete, Arcadia by name, being razed to the ground, the springs and water-courses, which before were very numerous in that locality, all at once dried up; but that, six years after, when the city was rebuilt, the water again made its appearance, just as each spot was again brought into cultivation.

(5.) Earthquakes also are apt to discover or swallow[3] up springs of water; a thing that has happened, it is well known, on five different occasions in the vicinity of Pheneus, a town of Arcadia. So too, upon Mount Corycus,[4] a river burst forth; after which, the soil was subjected to cultivation. These changes are very surprising where there is no apparent cause for them; such as the occurrence at Magnesia,[5] for instance, where the warm waters became cold, but without losing their brackish flavour; and at the Temple[6] of Neptune in Caria, where the water of the river, from being fresh, became salt. Here, too, is another fact, replete with the marvellous—the fountain of Arethusa at Syracuse has a smell of dung, they say, during the celebration of the games at Olympia,[7] a thing that is rendered not improbable by the circumstance,[8] that the river Alpheus makes its way to that island beneath the bed of the se-a. There is a spring in the Chersonesus of the Rhodians[9] which discharges its accumulated impurities every nine years.

Waters, too, sometimes change their colour; as at Babylon, for example, where the water of a certain lake for eleven days in summer is red. In the summer season, too, the current of the Borysthenes[10] is blue, it is said, and this, although its waters are the most rarefied in existence, and hence float upon the surface of those of the Hypanis;[11]—though at the same time there is this marvellous fact, that when south winds prevail, the waters of the Hypanis assume the upper place. Another proof, too, of the surpassing lightness of the water of the Borysthenes, is the fact that it emits no exhalations, nor, indeed, the slightest vapour even. Authors that would have the credit of diligent research in these enquiries, assure us that water becomes heavier after the winter-solstice.