And narrate, and cut, and do, and say -- add in notes. Here an account is given of the effects made by the waters in the aforesaid place. All lakes and all gulfs of the sea and all inland (Mediterranean) seas are born from the rivers that pour their waters into them and from the impediments to their descent. In the Mediterranean Sea -- divider of Africa from Europe and of Europe from Asia, by means of the Nile and the Tanais (Don) that pour their waters into it -- one asks what is the greater impediment preventing the course of its waters from returning to the Ocean.

L - h - lago - c - b - fa. Ask experience of it in the minute demonstrations. You will therefore make the figuration of the Mediterranean Sea in the manner here shown in front, which should have its rivers proportioned to the size and figure of such a sea; and you will give the science, by means of experience of the courses of the waters, of what is thereby taken from the things uncovered and covered by the waters. And you will make the Nile pour in at f, the Tanais at o, the Po at h, and likewise the other rivers of sizes proportioned to that sea, which will have its outlet through the Strait of Gibraltar. Let the bottom of the sea be made of sand and of a flat surface, and so at once you will see where such motion of water takes away and where it deposits. The course of a river has two principal reflections, of which one is from the bottom to the surface, and the other is from one bank to the other. And if they meet one another, the impetus of the striker always joins to the struck; and if the striker is of greater quantity than the thing struck, then one part of the greater, equal to the whole of the struck thing, will reflect backward, and the other will follow its first incident motion. And this I have proved in its place. Of the floods of the greatest rivers. The floods of rivers are generated when the mouths of the valleys cannot give issue to the waters received from that valley in the same time that the valley receives them. The motion of water becomes the swifter the greater its descent. Of the wave. The wave is an impression of reflected percussion, which will be greater or smaller in proportion to the greater or smaller percussion. The wave is never alone, but is mixed with as many other waves as are the inequalities that the object has where such wave is generated. In one same time innumerable other waves will move over the greatest wave of an open sea, which move by different aspects. If you throw the stone into the open sea from different sides, all the waves that strike those sides reflect toward the percussion, and in the encounter with the other incident waves they never impede each other's course. Waves of equal size, motion and power, meeting with contrary motions, reflect at equal angles one from the percussion of the other. That wave will be of greater eminence which is born of greater percussion, and so conversely. The wave generated in small pools many times goes and returns from the struck place. The more times the wave goes and comes, the smaller the width of water of the pool where it is generated, and so conversely. Only in the greatest open sea do the waves go without reflection; in small pools one same percussion gives birth to many incident and reflected motions. The greatest wave is clothed with innumerable other waves that move to different aspects, which sink more or less deeply the more or less power they are born of. The greatest wave clothes itself with various waves, which move to as many various aspects as were the various places whence they divided. One same wave, generated in a small pool, gains so much greater a number of other waves upon itself, the more percussion and reflection it has on the opposite shores. Greater is the motion of the wave than the motion of the water of which it is composed. Many waves turned to various aspects can be generated between the surface and the bottom of one same water in one same time. The whirling (vortiginous) motions can follow the straight motions of each wave. All the impressions of the percussions made upon the water can penetrate one another without their destruction. Never does one wave penetrate another, but they only reflect from the place of their percussion.