156 Of the Advancement of Learning, L i b . V. 



13. Let it be inquired what is the line and dirediion of the Motion 

 of Gravity 5 and how far it may follow either the centre of the earth, 

 that isjthe raafiof the Earth, or the centre of the Body itfelf, that is, 

 the cointention and driving on of the parts thereof, for thofe centres 

 are profitable in demonftration, but of no ufe in Nature. 



14. Let it be inquired to\xc\\\v\g\.h.t comparifon of the Motion of Gra- 

 vity, with other Motions ; what Motions it matters, to what it yields? 

 As in the Motion, which they call, violent^ which is repreft and bridled 

 for a time 5 as when a far greater weight of Iron is drawn up by a finall 

 Load-ftone, the Motion of Gravity gives place to the Motion of Syof 

 pathy. 



1 5. Let inquiry be made of the Amotion of Air, whether it be carried 

 upwards, or be collateral and indifferent? Which is a hard thing to 

 find out, but by (bme exquifite Experiments : for the glittering appa- 

 rition of Air in the bottom of Water, is rather by the Percuflion of 

 Water, than by the Motion of Air; being the fame emication maybe 

 made in Wood. But Air mingled with Air dilcovers no Experiment^ 

 becaufe Air in Air exhibits Levity no lefs , than Water in Water doth 

 Gravity : But in a Bubble drawn over with the inclofure of a thin Skin, 

 itftaysfor atime. 



1 6. Let it be inquired what is the Term of Levity, for fure their mean- 

 ing fwho made the Centre of the Earth, the Centre o^ Gravity^ is not, 

 that the ultimate convexity of Heaven (hould be theftint and limits of 

 Levity: Or rather, that as ponderous Bodies feem to be lb far carried, 

 that there they may caft Anchor as atafixt Pillar ; fo light Bodies are 

 (bfar carried, that they may begin to wheel about, and come to a mo* 

 tion roithout termination .-? ^ • 



1 7. Let inquiry be made, why vapouj s and exhalations Qiould be car- 

 ried as high as the middle Region of the Air(as they call it);feeing they 

 arc fomewhat a grols fubftanee ; and the beams of the Sun by turns ("af 

 in the night) ceale their Operation. 



18. Let inquiry be made of the condu& of. the Motion of Flame up" 

 vpards j which is the more abftrufe , becaufe Flame exfpires every mo- 

 ment ; fave perchance in the imbracement of greater Flames z 

 For Flames feparated and broken off from their continuation, laft not 

 long. 



19. Let inquiry be made of the afcendant Alotion of the AUivity of 

 Heat, as when the Heat of red-hot Iron affedeth rather to mount up- 

 wards, than to move downwards ? The exq^iple therefore of particular 

 Topick^ may be made in this manner 5 in the mean time, what we have 

 begun toadvife, we do again admonifli, which is, that men vary their 

 particular Topic^sfo, as after farther Progreffion made by Inquiry, they 

 do fubftitute one, and after that another Topick^, if ever they defireto 

 reach the top of Sciences. As for us, we attribute (b much to particular 

 Topickj, as we do defign to make » particular Work of them upon (bme 

 Subjefts in Nature, which are more obfervable, and more ob(cure , For 

 we are Commanders of ^efiions^ not fo of things'. And thus of Inven' 

 tion. 



Chap. 



