270 NATURAL HISTORY 



of the Hyades and the Pleiades, and concerning storms at 

 the rising of Arcturus. And so much concerning the moon 

 and stars. 



7. The sun is questionless the primary efficient of many 

 winds, working by its heat on a twofold matter, namely, 

 the body of the air, and likewise vapours and exhalations. 



8. When the sun is most powerful, dilatates and extends 

 the air, though it be pure and without any commixion one 

 third part, which is no small matter; so that by mere 

 dilatation there must needs arise some small wind in the 

 sun s ways; and that rather two or three hours after its 

 rising than at his first rise. 



9. In Europe the nights are hotter, in Peru three hours 

 in the morning, and all for one cause, namely, by reason of 

 winds and gales ceasing and lying still at those hours. 



10. In a vitro calendar!, dilatated or extended air beats 

 down the water, as it were, with a breath ; but in a vitro 

 pileato, which is rilled only with air, the dilatated air swells 

 the bladder, as a manifest and apparent wind. 



11. We have made trial of such a kind of wind in a 

 round tower, every way closed up. For we have placed a 

 hearth or fireplace in the midst of it, laying a fire of char 

 coal thoroughly kindled upon it, that there might be the 

 less smoke, and on the side of the hearth, at a small dis 

 tance, hath been a thread hung up with a cross of feathers, 

 to the end that it might easily be moved. So after a little 

 stay the heat increasing, and the air dilatating, the thread 

 and the feather cross which hung upon it waved up and 

 down in a various motion ; and, having made hole in the 

 window of the tower, there came out a hot breath, which 

 was not continual, but with intermission and waving. 



12. Also the reception of air by cold, after dilatation, 

 begets such a wind, but weaker, by reason of the lesser 

 force of cold. So that in Peru, under every little shadow, 

 we find not only more coolness than here with us (by anti- 

 peristasis), but a manifest kind of gale through the recep 

 tion of air when it comes into the shade. And so much 

 concerning wind occasioned by mere dilatation or reception 

 of air. 



13. Winds proceeding from the mere motion of the air, 

 without any commixion of vapours, are but gentle and soft. 

 Let us see what may be said concerning vapoury winds (we 

 mean such as are engendered by vapours), which may be so 

 much more vehement than the other, as a dilatation of a 

 drop of water turned into air exceeds any dilatation of air 



