I 5 2 BACON 



heavier parts of the entire body : whence curious separations 

 are often made, as in the separation of wine and water, the ris- 

 ing of cream from milk, etc. 



13. Inquire what is the line and direction of the motion of 

 gravity, and how far it respects the earth's centre ; that is, the 

 mass of the earth ; or the centre of its own body, that is, the appe- 

 tite of its parts. For these centres are properly supposed in 

 demonstrations, but are otherwise unserviceable in nature. 



14. Inquire into the comparative motion of gravity, with other 

 motions, or to what motions it yields, and what it exceeds. 

 Thus in the motion they call violent, the motion of gravity is 

 withheld for a time ; and so when a large weight of iron is 

 raised by a little loadstone, the motion of gravity gives way to 

 the motion of sympathy. 



15. Inquire concerning the motion of the air, whether it rises 

 upwards, or be as it were neutral, which is not easy to be dis- 

 covered without some accurate experiments ; for the rising up 

 of air at the bottom of water, rather proceeds from a resistance 

 of the water, than the motion of the air, since the same also hap- 

 pens in wood. But air mixed with air makes no discovery; 

 for air in air may seem as light, as water in water seems heavy ; 

 but in bubbles, which are air surrounded with a thin pellicle of 

 water, it stands still for a time. 



1 6. Let the bounds of levity be inquired after; for though 

 men make the centre of the earth the centre of gravity, they will 

 perhaps hardly make the ultimate convexity of the heavens the 

 boundary of levity ; but rather, perhaps, as heavy bodies seem 

 to be carried so far, that they rest, and grow, as it were, immov- 

 able ; light bodies are carried so far, that they begin a rotation 

 or circular motion. 



17. Inquire the cause why vapors and effluvia are carried so 

 high as that called the middle region of the air, since the matter 

 of them is somewhat gross, and the rays of the sun cease alter- 

 nately by night. 



18. Inquire into the tendency of flame upwards, which is the 

 more abstruse, because flame perishes every moment, unless 

 perhaps in the midst of larger flames ; for flames broken from 

 their continuity are of small duration. 



19. Inquire into the motion and activity of heat upwards ; as 

 when heat in ignited iron sooner creeps upwards than down- 

 wards. And thus much by way of example of our particular 



