C^oci ) 
it maybemuch funk by this time from what foineofh/s friends 
very worthy men and competent Judges of mens habih'ties / 
from hence have reprclentcd uatohlmiTo return then to our 
Author, He 
In the fourth Trad endeavours experimentally to flbeWjthat, 
though not only the Peripatetic^^ Schools, but the generality 
ofPhilofophers both antient and modern, do as well as the 
Vulgar, afcribe the Afceofion of Lighter bodips in water to an 
Internal principle5by them called Pofitive Levity 5 yet we need 
not admit any fuch thing for the true and adequate caufe of 
the emerfion of wood and (uch lighter bodiesj let go under 
water. 
lu they5^/^, he adds to the Proofs, already given of the 
Power ot the Spring of the Air3fome of the Operations he hath 
difcovetM it to have upon Bodies placed under water. In the 
doing of which he employs two forts ofTryals, (hewing, that 
a fmall quantity of incloicd Air may by itsprefliire haveacon- 
fiderablc operation upon bodies cover d with water, not with- 
ftandingtheinterpofition ofiheliquor 5 which PrefFure may 
bemanifcftcd, by what it direftly and pofitively operates 
upon bodies under water 5 andhy the things that regularly en- 
fue upon the Removal of the inclofcd Air, or the weakning of 
itsSpring* 
lnxh% fixth and laft, the Author conGdering that it hath 
prov'd a great Impediment to mens freely acquiefcing in the 
Doftrine founded on the ph^ftometta of h\s Phyfico-Mechanical 
Experiments, that if the Atmofphere could really cxercifc lb 
great a Prefliire, as he afcribcs to it, it would unavoidably op? 
prefs and cruQi all the bodies expos'd to it ; He therefore em- 
ploys in this Trad divers weighty Confidcrations and rema|k' 
able Exf)eriments to remove the force of that plaufible OB- 
5*edion. 
L Ejperien%e intorm i diver fe cofe naturali^ particolar- 
meme k quelle che ci fonportate daW Indie *^fatte da Francefco 
Redi. I^Firenze, |67i« 4'* 
'T^His Learned and Qbferving Author, defirousto examine 
manyTraditions about Natural thingSjtakes occafion from 
ciertain Sna^e-Jiones^ deiFcribcd by Garcias ab Horta and others^ 
Bbbbbb 2 and^ 
