OF WINDS. 271 



already made : which it doth by many degrees, as we 

 showed before. 



14. The efficient cause of vapoury winds (which are they 

 that commonly blow) is the sun, and its proportionate heat ; 

 the matter is vapours and exhalations which are turned and 

 resolved into air. I say air (and not any thing but air), yet 

 at the first not very pure. 



15. A small heat of the sun doth not raise vapours, and 

 consequently causes no wind. 



16. A mean or middle heat of the sun raiseth and excites 

 vapours, but doth not presently dissipate them. Therefore 

 if there be any great store of them they gather together into 

 rain, either simply of itself, or joined with wind : if there 

 be but small store of them they turn only to wind. 



17. The sun s heat in its increase inclines more to the 

 generation of winds, in its decrease to rains. 



18. The great and continued heat of the sun attenuates 

 and disperses vapours and sublimes them, and withal 

 equally mixes and incorporates them with the air, whereby 

 the air becomes calm and serene. 



19. The more equal and continuate heat of the sun is 

 less apt for the generation of winds ; that which is more 

 unequal and intermitted is more apt. Wherefore in sailing 

 into Russia they are less troubled with winds than in the 

 British sea, because of the length of the days; but in 

 Peru under the equinoctial are frequent winds, by reason 

 of the great inequality of heat, taking turns night and day. 



20. In vapours is to be considered both the quantity and 

 quality. A small quantity engenders weak winds, a mean 

 or middle store stronger ; great store engenders rain, either 

 calm or accompanied with wind. 



21. Vapours out of the sea and rivers, and overflown 

 marshes, engender far greater quantity of winds than the 

 exhalations of the earth. But those winds which are en 

 gendered on the land and dry places are more obstinate and 

 last longer, and are for the most part such as are cast down 

 from above. So that the opinion of the ancients in this is 

 not altogether unprofitable ; but only that it pleased them, 

 as in a manner dividing the inheritance, to assign rain to 

 vapours, and to winds exhalations only, which things 

 sound handsomely, but are vain in effect and substance. 



22. Winds brought forth out of the resolutions of snow 

 lying upon hills are of a mean condition between water and 

 land winds ; but they incline more to water, yet they are 

 more sharp and moveable. 



