Certain writers seek for a rational explanation of this practice. One 1 school, adopting the only line that comports with philosophy, deny the possibility of making any bargain with hail and buying off storms by paltry presents, true, though it be, that gifts overcome even gods. Others affirm their suspicion that blood itself contains a virtue potent enough to avert and repel a cloud. But how, I ask, should a drop or two of blood possess a virtue to reach on high and influence the clouds? Is it not much easier to say, the whole thing is a parcel of lies? But Cleonae was strict in dealing with its warders who had 2 received charge of looking out beforehand for the storm, if it happened that through their neglect the vineyards had been beaten down or the crops laid. And among ourselves, too, at Rome the laws of the Twelve Tables introduce safeguards against the blighting of a neighbour’s crops by charms. Antiquity as yet untutored entertained the belief that rain could be attracted or repelled by incantations. The impossibility of such fancies is so evident that one need not enter a school of philosophy in order to be taught how to disprove them. VIII I shall add one more remark which you will be very glad, I am sure, to approve and applaud. It is asserted that snow is formed in the part of the atmosphere near the earth. This layer has more heat than any other, and that for three reasons. One is that all evaporation from the earth, containing as it does much dry, glowing matter, is always the hotter, the more recently it has left the ground. The second is that the sun’s rays are reflected from the ground and return upon themselves. Their reflection heats up the parts next the ground, which thus have more warmth from getting the sun’s heat twice. The third reason is that the upper regions are more subject to wind; but all places that are sunk are less wind-swept. IX To the foregoing Democritus’ explanation falls to be added. Every body receives heat more quickly and retains it longer in proportion to its solidity. For example, if three vessels, of copper, glass, and silver respectively, are set in the sun, the heat will penetrate the copper one soonest and will remain in it longest. The reason why Democritus is of this opinion may also be added. In the bodies, he says, that are harder, more compact, and dense, the openings must of necessity be smaller than in others, and in each of the openings the film of air must be thinner. It follows that just as smaller baths and smaller cylinders are heated more rapidly than others, so these concealed apertures, so small as to elude the eye, both feel the heat more quickly, and by reason of this same smallness of calibre give back more slowly the heat they have received. X