106 NATURAL HISTORY. 



rest ; which in exercise are beaten (many times) too 

 much : and for the same reason (as we have noted 

 heretofore) galley-slaves are fat and fleshy, because 

 they stir the limbs more, and the inward parts less. 



Experiment solitary touching globes appearing flat at 

 distance. 



878. All globes afar off appear flat. 1 The cause is, 

 for that distance, being a secondary object of sight, is 

 not otherwise discerned than by more or less light : 

 which disparity when it cannot be discerned, all seem- 

 eth one : as it is (generally) in objects not distinctly 

 discerned ; for so letters, if they be so far off as they 

 cannot be discerned, shew but as a duskish paper ; and 

 all engravings and embossings (afar off) appear plain. 



Experiment solitary touching shadows. 



879. The utmost parts of shadows seem ever to 

 tremble. 2 The cause is, for that the little motes 

 which we see in the sun do ever stir, though there be 



O 



no wind ; and therefore those moving, in the meet 

 ing of the light and the shadow, from the light to the 

 shadow, and from the shadow to the light, do shew 

 the shadow to move, because the medium moveth. 



Experiment solitary touching the rolling and breaking 

 of the seas. 



880. Shallow and narrow seas break more than deep 



1 Aristotle (Prob. xvi. 7.) remarks this in the case of the sun and moon 

 That a luminous globe appears uniformly bright, shows that the intensity 

 with which light radiates varies as the sine of the angle its direction makes 

 with a normal to the radiating surface. Were this not the case, the bright 

 ness would increase indefinitely from the centre towards the circumference. 



2 Arist. Prob. xvi. 12. 



