n - b - m - o a - d. Three are the winds that bend westward the rivers that pour into the Mediterranean Sea along the shores that face south. It is proved thus. The sand that the winds drive into the water is no longer in the power of the winds, because it is weighed down by the water that covers it and shields it against those winds. Therefore the river n m, which pours into the sea toward the south, will begin its motion toward the west when the wind called Greco [north-east], and Levante [east] and Scirocco [south-east] blow, which at different times push the dry sand of the shore and cast it into the sea, where it sinks and settles upon the sea floor; but Aquilone, called Greco, casts it toward Libeccio [south-west], and Scirocco casts it toward Maestro [north-west]. But the southern waves, striking the shore, throw such sand back toward the river, and the river throws it back toward the sea; and where the waves reflected from the shore meet the waves coming toward the shore, there the motion of these waves stops, and for this reason the power of their motion fails. Therefore the sand that muddies the water descends to the bottom, and this is the sand that makes an embankment of itself and bends the aforesaid river to the west. Why does the course of the aforesaid river not bend as much to the east as to the west? Because it is proved that the sea flows to the west and not to the east. Therefore we shall make a bridge, wide and low as the shore, of thick beams.

Mound — Levelled ground.

a. A bridge.

On rivers that pour their waters into the sea.

m a - r n. Of straight waters, of equal flow and width, over a flat bed and [equal] distance from the sea, that one will make a more sloping surface to which is added a more abundant quantity of water.

On straight rivers. That water is of slower course which is nearer the bottom, the bed being flat and of uniform width. Of rivers whose bed is lower than the surface of the sea water, there flows only that water which is above the sea's level. And this is manifest to us by the ninth [proposition], which says: 'water of equal height has of itself no motion'; and by the converse, that water will have motion which is of unequal height, with so much greater or lesser velocity as the inequality is of greater or lesser difference. Of waters that descend from one height to the same lowness with equal length of course, the disgregable will be swifter than the concurrent; and this arises because the disgregable acquires more declination than the concurrent.

Tell me, do you love...

To a faithful friend there is no comparison.