_Vapour_ and _Smoak_ are both fluid Bodies: but, Smoak is more of the Nature of Oyl, than Water; and Vapour more of the Nature of Water, than Oyl; they are dividable: and may be join'd, as other Elements: also, they are of a Metamorphosing Nature, as to change and rechange; but, when they are Metamorphosed into the form of Air, that Air is a gross Air, and is, as we say, a corruptible Air. As for Vapour, it is apt to turn into Wind: for, when it is rarified beyond the Nature of Vapour, and not so much as into the Nature of Air, it turns into some sorts of Wind. I say, some sorts: and certainly, the strongest Winds are made of the grossest Vapours. As for Smoak, it is apt to turn into some sorts of Lightning; I say, apt: for, both Vapour and Smoak can turn into many sorts of Metamorphosed Elements. As for Wind, it proceeds either from Rarified Vapour, or Contracted Air. And there are many sorts of Vapours, Smoaks, and Winds; all which sorts of Vapours and Smoaks, are apt to ascend: but, Wind is of a more level action. As for Clouds, they cannot be composed of a Natural Air; because Natural Air is too rare a Body to make Clouds. Wherefore, Clouds are composed of Vapour and Smoak: for, when Vapour and Smoak ascends up high without transformation, they gather into Clouds, some higher, some lower, according to their purity: for, the purer sort (as I may say for expression-sake) ascends the highest, as being the most agil. But, concerning the Figurative Motions of Vapour and Smoak, they are Circles; but of Winds, they are broken Parts of Circular Vapours: for, when the Vaporous Circle is extended beyond its Nature of Vapour, the Circumference of the Circle breaks into perturbed Parts; and if the Parts be small, the wind is, in our perception, sharp, pricking, and piercing: but, if the Parts are not so small, then the wind is strong and pressing: but wind, being rarified Vapour, is so like Air, as it is not perceived by human sight, though it be perceived by human touch. But, as there are hot vapours, cold vapours, sharp vapours, moist vapours, dry vapours, subtil vapours, and the like; so there is such sorts of winds. But, pray do not mistake me, when I say, that some sorts of winds are broken and perturbed Circles, as if I meant, such as those of Lightning: for, those of Lightning, are extended beyond the degree of Air; and those of Vapours, are not extended to the degree of Air: also, those of Lightning, are not perturbed; and those of Wind, are perturbed. Again, those of Lightning, flow in Streams of smooth, small, even Lines; those of Wind, in disordered Parts and Fragments. CHAP. XXVI. Of WIND.