OF WINDS. 287 



2. If the sails were extended even and equally, it would 

 be doubtful which way the inclination would be, as in the 

 fall of a staff; but when the nearer side which meets with 



1 the wind casts the violence of it upon the lower side, and 

 | from thence into distances, so that when the lower side 

 I receives the wind, like the palm of the hand, or the sail of 

 I a ship s boat, presently there is a turning on that side. But 

 ! this is to be observed, that the beginning of the motion 



proceeds not from the first impulsion, which is direct and 

 i abreast, but from the lateral impulsion, which is after the 



compression or straightening of the wind. 



3. We made some proofs and trials about this, for the in 

 creasing of this motion, as well to be assured we had found 

 the cause as also for use; feigning an imitation of this 

 motion, with paper sails, and the wind of a pair of bellows. 

 We therefore added to the side of the lower sail a fold 

 turned in from the wind, that the wind being become a 

 side wind might have somewhat more to beat upon, which 

 did no good, that fold not so much assisting the percussion 

 of the wind, as in consequence hindering the cutting of the 

 air. We placed behind the sails, at some distance, certain 

 obstacles as broad as the diameter of all the sails, that the 

 wind being more compressed might hit the stronger; but 

 this did rather hurt than good, the repercussion dulling 

 the primary motion. Then we made the sails of a double 

 breadth, that the wind might be the more restrained, and 

 there might be a stronger lateral percussion, which at last 

 proved very well ; so that the conversion was caused by a 

 far milder gale, and did turn a great deal more swiftly. 



Mandate. Peradventure this increase of motion might 

 more conveniently be made by eight sails, than by four, 

 doubling the breadth, unless too much weight did over- 

 burthen the motion ; which must have trial made of it. 



Mandate. Likewise the length of sails doth much con 

 duce to the motion. For in wheelings a slight violence 

 about the circumference is equivalent to a far greater about 

 the centre. But then this inconvenience follows, that the 

 longer the sails are the more distant they are at the top, 

 and the wind is so much the less straightened. Peradven 

 ture the business would go well if the sails were a little 

 longer and broader towards the top, like the outermost end 

 of an oar. But this we are not sure of. 



Monition. If these experiments be made trial of in wind 

 mills, care must be taken of the windmill posts, and the 

 foundations of it ; for the more the wind is restrained the 



