Thales conjectures that the Etesian or anniversary northern winds blowing strongly against Egypt heighten the swelling of the Nile, the mouth of that river being obstructed by the force of the sea rushing into it. Euthymenes the Massilian concludes that the Nile is filled by the ocean and that sea which is outward from it, the last being naturally sweet. Anaxagoras, that the snow in Ethiopia which is frozen in winter is melted in summer, and this makes the inundation. Democritus, that the snows which are in the northern climates when the sun enters the summer solstice are dissolved and diffused; from those vapors clouds are compacted, and these are forcibly driven by the Etesian winds into the southern parts and into Egypt, from whence violent showers are poured; and by this means the fens of Egypt are filled with water, and the river Nile hath its inundation. Herodotus the historian, that the waters of the Nile receive from their fountain an equal portion of water in winter and in summer; but in winter the water appears less, because the sun, making its approach nearer to Egypt, draws up the rivers of that country into exhalation. Ephorus the historiographer, that in summer all Egypt seems to be melted and sweats itself into water, to which the thin and sandy soils of Arabia and Lybia contribute. Eudoxus relates that the Egyptian priests affirm that, when it is summer to us who dwell under the northern tropic, it is winter with them that inhabit under the southern tropic; by this means there is a various contrariety and opposition of the seasons in the year, which cause such showers to fall as make the water to overflow the banks of the Nile and diffuse itself throughout all Egypt. CHAPTER II. OF THE SOUL. Thales first pronounced that the soul is that being which is in a perpetual motion, or that whose motion proceeds from itself. Pythagoras, that it is a number moving itself; he takes a number to be the same thing with a mind. Plato, that it is an intellectual substance moving itself, and that motion is in a numerical harmony. Aristotle, that it is the first actuality [Greek ommitted] of a natural organical body which has life potentially; and this actuality must be understood to be the same thing with energy or operation. Dicaearchus, that it is the harmony of the four elements. Asclepiades the physician, that it is the concurrent exercitation of the senses. CHAPTER III. WHETHER THE SOUL BE A BODY, AND WHAT IS THE NATURE AND ESSENCE OF IT.