C 22 ) 
may pafs through it. The water which is in E B, is by the 
Forcer D C forced up , whereby the Air, that is between A 
and.E, is comprefTed into an hundred times lefs room than it 
hath before this prefTure. And , forafmuch as 'tis certain to 
me, that no Body can be brought into leffer Dimenfions than 
it is, except fome other body be at the fame time diflodged 
out of it , nor any Body made bigger , but fome other bodies 
muft come into it ; the Air therefore cannot be comprefs'd 
together, and be made an hundred times lefs, but the Afr muft 
permeat the Glafs; as 'tisalfo the common opinion , that the 
firft and fubtileft fluff of the Air pafTes through all clofe Bo- 
dies. I conceive then, that the firft: and fineft matter of Air 
confiftsof fomefhing like grains of Sand, taking it from the 
fineft fort to thegroffeft • itsfecond matter, of fomething like 
Bodies between the grofleft Sand-corns and Strawberries ; its 
third matter, of fomething like Bodies between Straw-berries 
and Cherries 5 and that all thefe parts ar&foft and fluid. I fay 
then, that if the particles of the firft fluff alwaics pafs 
through the clofeft bodies ( which I here fuppofe to be Sand- 
grains) itmuft follow, that by my prelTure in the Glafs-pipe 
1 force through the Glafs divers particles of thefecond fluff 
fthey being all fluid) and comprefs clofe together the more 
diftant fecond and third fluff, and make them change their fi- 
gure , and even , in cafe there be any of the firft fluff latifant 
m the fecond and third ftuff, I caiife it by the forcible pref- 
fure to be diflodged together , and to pafs through the Glafs* 
This preffure is greater than many imagine. The diameter of 
my Glafs being of about ^ of an inch ; if by my prefFing at 
C 1 I ufed the forcebuf of 25 /^. weight, it follows, if I had 
a Glafs-pipe of a whole inch diameter, it would, to keep 
proportion with a Glafs-pipe of -\ inch , require a force of 
2 500 pounds. 
Thefe things thus fuppofed, being defirous to try, whether 
any particles of the fecond fluff, or other parts fomewhat 
bigger than the fmalleft fluff, could be preffed or forced 
through the Glafs ; I prepared for that purpofe another Glafs- 
pipeCas Pi^.2.)and took a third one of half its length^and fo 
much wider, as to flioot over the fecond, as here G M ; Which 
^ider pipe I clofed to G by means of the fire, leaving it open 
