There are other peculiarities attaching to waters of different kinds, 9 of which no explanation can be offered. For example, why should Nile water make women more fruitful? So effective is it in this respect that in some instances wombs shut up in prolonged barrenness have relaxed so as to render conception possible. Or why should certain waters in Lycia prevent miscarriage, being sought after by ladies who are subject to this frailty? For my own part I set these down among vulgar errors. It is firmly believed by people that certain waters, whether applied outwardly or taken inwardly, affect the body with scab, certain with leprosy and foul blotches over the skin. Water gathered from dew, they say, has this fault. Wouldn’t any one suppose that water that 10 turns into ice is the heaviest of all? The truth is just the opposite of this. The change takes place in the thinnest water, which for that very reason is most easily congealed by the cold. The origin of the stone that resembles ice is plain from the very name used for it by the Greeks. They apply the term crystal (κρύσταλλος) equally to the transparent stone and to the ice from which the stone is supposed to be formed. Rain water, which contains very little solid matter, once it is frozen becomes more and more condensed through the persistence of the longer cold until all the air is expelled, and it is compressed to the last degree; then what was once moisture is changed into stone. XXVI Some rivers rise in summer like the Nile, of which I will give an 1 account later on. Theophrastus makes himself responsible for the statement that in Pontus likewise certain rivers rise in the summer season. Four different causes are assigned for this. First, the earth is at that period most readily changed into moisture. Second, there are in the remote districts heavier rains, the water from which, finding its way by secret channels, comes unnoticed to swell the volume of the rivers. A third explanation is that the estuary is exposed to more frequent winds, and is lashed by the sea waves; the river is checked and seems to increase because it cannot discharge freely. The fourth reason connects itself with the heavenly bodies. These bodies by 2 their more severe pressure during certain months drain the rivers; when they retire to a greater distance, the waste and drain are less. What was previously lost now accrues by way of increase. Certain rivers fall visibly into some grotto or other, and thus are withdrawn from sight; some are gradually wasted and disappear. They return, however, at some distance off and recover their name and course. The reason is plain enough. There is vacant space underground. All liquid naturally 3 is carried to the lower level and to the unoccupied space. The rivers received into these recesses have run their course there in secret. But as soon as any solid obstacle blocks the way, they burst through the