23.

It is perhaps owing to this cause that the water of the Nile boils, as he says, with one half of the heat which other water requires. In proportion however, he says, as the water of the Nile traverses in a straight line, a long and narrow tract of country, passing through a variety of climates and of atmosphere, while the Indian rivers are poured forth into wider and more extensive plains, their course being delayed a long time in the same climate, in the same degree the waters of India are more nutritious than those of the Nile; they produce larger animals of the cetaceous kind, and in greater number (than the Nile), and the water which descends from the clouds has already undergone the process of coction.