( 51^7 ) 
Our common Air being an aggrega te of very Heteroge- 
neous parts 5 wemay well fuppofe fome ojf them to be 
SpriDgy^aDd others not to be fo* The Springy parts we may 
conceive to be fo many confident Bodies^ like finall hairs or 
(pringy threads wrapped up in different forms and varioufly 
intangled^and (b as to form many vacuities capable of ^d- 
roitting(vihat(bever other parts of the Air may be ftippofcd 
to be)fomc Fluid matter^whieh may infiouate into thofe va- 
cuities, (as water in a bundle of Buflbes,) without difturb- 
ingthe Texture of thofe Springy parts 5 and which may 
prcfs as a Weighty but not as a Sprifjg^ ( of which diftinftioo 
UtXJdp.i^ De motu\ Scholprop 1 1. & Schol.pr0p.i^.pag,y2^^ 
730,7323735.) 
Now if 3 in the Torricellian Tube , there be a quantity 
of fuch Springy matter, the Spring hereof will be of equal 
ftrcngth with that of External Air, (and therefore able to 
countcrballanceit 3 though its weight be much Jcfi^) be- 
caufe admitted with fuch a tenfurej (ibid, prop. 12,1^ ) But 
if only an Un-fpringy Fluid (which prefseth but as a Weight 
Dot as a Spring,) and this defended by the glafs-Tubc from 
any other prclTure,. fa ve that of its own weight 5 it willftill 
be too weak to force its own way y till its fingle weight be 
equivalent to that with which it is to encounter 5 which is,, 
notonely the Springy part of the Air^ but alfo that Fluid 
Un-fpringy part 3 which though (becaufe Fluid) it would 
give way to a Springy body preffing through it 5 yec not 
to this Fluids- like it felf, and deftitute of fuch a Spring 5 
and is therefore able to^ keep it up to a much greateiD 
height thanit could do if un-cleanfcd of Springy Air : Sa 
long at leaft as till fome Springy body be admicted^or fome 
Goncuffion, equivalent to it , put it io motionf but being 
once in motion 5 it will fo continue (as a Bullet iiBpeird 
by Gun-powder, or an Arrow out of a BoW:) till ftopped 
by (bme Pofitive force equivalents 
I do not deny, but that this expliGation maybe fubjeft 
to fome Difficulties and Exceptions , but I thinks fewer 
rhan that of allowing the Glafs penetrable by this Subtile 
■matter.. Bu% 
