282 NATURAL HISTORY 



ship of five hundred tons or thereabout may bear almost as 

 large a sail as the other we speak of, which was almost as 

 big again. Whence it proceeds that lesser ships are far 

 swifter and speedier than great ones, not only by reason of 

 their lightness, but also by reason of the largeness of their 

 sails, in respect of the body of the ship ; for to continue 

 that proportion in bigger ships would be too vast and im 

 possible a thing. 



21. Each sail being stretched out at the top, and only 

 tied by the corners at the bottom, the wind must needs 

 cause it to swell, especially about the bottom where it is 

 slacker. 



22. The swelling is far greater in the lower sails than in 

 the upper, because they are not only parallelograms, and 

 the other more pointed at the top, but also because the ex 

 tent of the yard doth so far exceed the breadth of the 

 ship s sides to which they are fastened, that of necessity, 

 because of the looseness, there must be a great receipt for 

 the wind ; so that in the great ship which we proposed for 

 an example, the swelling of the sail in a direct wind may 

 be nine or ten feet inward. 



23. By the same reason it also happens, that all sails 

 which are swelled by the wind, do gather themselves into 

 a kind of arch or bow, so that of necessity much wind must 

 slip through ; insomuch, that in such a ship as we made 

 mention of, that arch may be as high as a man. 



24. But in the triangular sail of the mizenmast there 

 must of necessity be a lesser swelling than in the quadran 

 gular ; as well because that figure is less capable, as also 

 because that in the quadrangular three sides are slack and 

 loose, but in the triangular only two, so that the wind is 

 more sparingly received. 



25. The motion of the wind in sails, the nearer it comes 

 to the beak of the ship, the stronger it is, and sets the ship 

 more forward, partly because it is in a place where, because 

 of the sharpness of the beak-head, the waves are easilier cut 

 in sunder; but, chiefly, because the motion at the beak 

 draws on the ship, the motion from the stern and back part 

 of the ship doth but drive it. 



26. The motion of the winds in the sails of the upper 

 tier advances more than that in the lower tier, because a 

 violent motion is most violent when it is farthest removed 

 from resistance, as in the wings and sails of windmills ; 

 but there is danger of drowning or overturning the ship : 

 wherefore those sails are made narrower at the top, that 



