BOOK XVII. II. 12-15
Cold weather only does damage when it comes with northerly winds, or not at the proper seasons; indeed for a north-east wind to prevail in winter is most beneficial for all crops. But there is an obvious reason for desiring rain in that season, because it is natural for the trees when exhausted by bearing fruit and also by the loss of their leaves to be famished with hunger, and rain is a food for them. Consequently experience inspires the belief that a mild winter, causing the trees the moment they have finished bearing to conceive, that is to bud, again, this being followed by another exhausting period of blossoming, is an extremely detrimental thing. Indeed if several years in succession should take this course, even the trees themselves may die, since no one can doubt the punishment they suffer from putting forth their strength when in a hungry condition; consequently the poet who told us to pray for finer wintersa was not framing a litany for the benefit of trees. Nor yet is wet weather over midsummer good for vines. Trees benefited by snow.It has indeed been said,b thanks to the fertility of a vivid imagination,c that dust in winter makes more abundant harvests; but, quite apart from this, it is the prayer of trees and crops in common that snow may he a long time. The reason is not only because snow shuts in and imprisons the earth's breath when it is disappearing by evaporation, and drives it back into the roots of the vegetation to make strength, but because it also affords a gradual supply of moisture, and this moreover of a pure and extremely light quality, owing to the fact that rime is the foam of the waters of heaven. Consequently the moisture from snow, not inundating and drenching everything all at once, but shedding drops as from a breast in proportion to the thirst felt, nourishes all
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