The ocean, then, is like a river encircling the whole earth, and I think it is concerning it that the divine Scripture says, A river went out of Paradise Gen. ii. 10.. The water of the ocean is sweet and potable For ποταμὸς δὲ ὁ γλυκὺ ὕδωρ ἔχων ἐστί, reading πότιμον καὶ γλυκὺ ὕδωρ ἔχων.. It is it that furnishes the seas with water which, because it stays a long time in the seas and stands unmoved, becomes bitter: for the sun and the waterspouts draw up always the finer parts. Thus it is that clouds are formed and showers take place, because the filtration makes the water sweet.