IV
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I might take leave of the question here, holding that I had finished it. But I will give you good measure, and, having begun to trouble you with my speculations, I will discuss everything connected with the topic. One of the cognate questions is, why in winter there is snow but no hail, while in spring, after the worst of the cold is over, there are falls of hail. For let me be deceived for your benefit, though I may say I am fully persuaded of the truth of what I am about to affirm. I lend always a credulous ear to these trivial falsehoods; perhaps they deserve to be punished by having one’s mouth stopped, but they hardly call for the putting out of one’s eyes! In winter the atmosphere is stiff, and is therefore not as yet capable of being converted into water, but only into snow, to which the atmosphere is more akin. But when spring begins, a greater variation of the atmosphere ensues, and, the sky being warmer, the drops are larger. Therefore, as our poet Virgil says:
When rain-charged spring descends,
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there is a more violent change in the atmosphere, which everywhere opens up and relaxes through the action of the mere warmth. For this reason the clouds that are carried to earth are heavy and large rather than lasting. Winter rain is thin and persistent. The fall often occurs in the form of small, fine rain, with an admixture of snow. We call it a snowy day when the cold is intense and the sky leaden. Besides, when the north wind doth blow, producing its characteristic sky, there may be fine rain. With south wind the rain is more persistent, and the drops heavier.