24. This would not be admitted by the followers of Aristobulus, who say that the plains are not watered by rain. Onesicritus, however, thinks that rain-water is the cause of the peculiar properties of animals, and alleges in proof, that the colour of foreign herds which drink of it is changed to that of the native animals. This is a just remark; but it is not proper to attribute to the power of the water merely the cause of the black complexion and the woolly hair of the Ethiopians, and yet he censures Theodectes, who refers these peculiarities to the effects of the sun, in these words, “Near these approaching with his radiant car, The sun their skins with dusky tint doth dye, And sooty hue; and with unvarying forms Of fire, crisps their tufted hair.” There may be reason in this, for he says that the sun does not approach nearer to the Ethiopians than to other nations, but shines more perpendicularly, and that on this account the heat is greater; indeed, it cannot be correctly said that the sun approaches near to the Ethiopians, for he is at an equal distance from all nations. Nor is the heat the cause of the black complexion, particularly of children in the womb, who are out of the reach of the sun. Their opinion is to be preferred, who attribute these effects to the sun and to intense solar heat, causing a great deficiency of moisture on the surface [CAS. 696] of the skin. Hence we say it is that the Indians have not woolly hair, nor is their colour so intensely[354] dark, because they live in a humid atmosphere. With respect to children in the womb, they resemble their parents (in colour) according to a seminal disposition and constitution, on the same principle that hereditary diseases, and other likenesses, are explained. The equal distance of the sun from all nations (according to Onesicritus) is an argument addressed to the senses, and not to reason. But it is not an argument addressed to the senses generally, but in the meaning that the earth bears the proportion of a point to the sun, for we may understand such a meaning of an argument addressed to the senses, by which we estimate heat to be more or less, as it is near or at a distance, in which cases it is not the same; and in this meaning, not in that of Onesicritus, the sun is said to be near the Ethiopians. 25. It is admitted by those who maintain the resemblance of India to Egypt and Ethiopia, that the plains which are not overflowed do not produce anything for want of water. Nearchus says, that the old question respecting the rise of the Nile is answered by the case of the Indian rivers, namely, that it is the effect of summer rains; when Alexander saw crocodiles in the Hydaspes, and Egyptian beans in the Acesines, he thought that he had discovered the sources of the Nile, and was about to equip a fleet with the intention of sailing by this river to Egypt; but he found out shortly afterwards that his design could not be accomplished,