Chap. u. ^r^j///f0/BODIES. 117 



exa&ly according to the proportion of the diminifhing of its 

 denfity, as long as there is a fiiperproportipn of its dcnfity to 

 the medium : fince that fuch a fuperproportion (as we have de- 

 clared heretofore) maketh the mediums operation upon the 

 denfe body fcarce considerable. 



And hence you lee why a ftone or piece ofiron, is not carri- 

 ed out of its way as well as a feather; becauie the (tones motion 

 downwards is greater and ftronger then the motion of a fea- 

 ther downwards. And by confequence, the force that can deturn, 

 a feather from its courlc downwards, is not able to deturn a 

 ftone. And if it be replied, that it may be fo ordered that the 

 ftone fliall have no motion, before it be in the ftream of a river, 

 and notwithstanding ic will ftillmove downwards: we may an- 

 fwer, that confidcring the little declivity of the bed of fuch a 

 ftream, the ftrongeft motion of the parts of the ftream, muft nc- 

 ccflarily be downwards ; and consequently, they will beat the 

 ftone downwards. And if they do not the like to a feather or 

 other light body ; it is becaufe other parts of the ftream, do gee 

 under the light body* and beat it upwards, which they have noc 

 power enough to do to the ftone. 



Sixrhly, it may be objected, that if Elements do not weigh in g. 



their own fphercs j then their gravity and defending rnuft pro- Thefixthobje- 

 ceed from fbme other caufe and not from this percuflion of the anTthaiTaii * ' 

 atomes we attribute to it ; which percuflion we have determined heavy elements 

 goeth through all bodies whatfbever, and beateth upon every t 'heir V owa '" 

 fenfible part of them. But that Elements weigh not in their own f P heres ' 

 fpheres, appeareth out of the experience of a fyphon; for though 

 one leg of a fyphon, be funk never fb much deeper into the bo- 

 dy of the water,then the other leg rcacheth below the fuperficies 

 ot the water : ncverthelefle 5 if once the outward leg become full 

 of water, it will draw it out of the other longer leg : which ic 

 fhould not do, if the parts of water that arc comprised within 

 their whole bulke, did weigh feeing that the bulke of 

 water is much greater in the funk legge then in the other ; 

 and therefore thcfe (hould rather draw back the other water 

 into the ciftcrn, then be themfelves drawn out of it in:o the 

 a ire. 



To this we anfwcr,that it is evident theElements do weigh in 

 their own fphercsjat leaft,as far as we can reach to their fphercs: 



H for 



