IV
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But how, you will say, are winds then formed, for you won’t deny that they are formed? Not in any single way, I reply. Sometimes the earth herself emits a great quantity of air, which she breathes out of her hidden recesses. At other times a great and long-continued evaporation drives the emissions from the depths up on high, where the change which the mixed breath undergoes issues in wind. A suggestion has been made which I cannot make up my mind to believe, and yet I cannot pass over without mention. In our bodies food produces flatulence, the emission of which causes great offence to one’s nasal susceptibilities; sometimes a report accompanies the relief of the stomach, sometimes there is a more polite smothering of it. In like manner it is supposed the great frame of things when assimilating its nourishment emits air. It is a lucky thing for us that nature’s digestion is good, else we might apprehend some less agreeable consequences. Is it not, then, nearer the truth to say that numerous particles are constantly borne up from every part of the world; and when they are accumulated and subsequently begin to be rarefied by the sun, wind starts up? It is a general principle that anything contained in a narrow space when it expands tries to get more room.