_ ( 51^7 ) 
Our commoa Air being ao aggregate of wryHctcroge^ 
neous parts , we may well foppofe fame of them to be 
Springy^aDd others not to be fo* The Springy parts we may 
conceive to be fo many confident Bodies, like iinall hairs or 
fpringy threads wrapped up in different forms and varioufly 
intangled5and fo as to form many vacuities capable of ad« 
initiiDg(whatfbever other parts of the Air may be fuppofed 
to be)fomc Fluid matter^which may infinuate into thofe va- 
cuities:, (as water in a bundle of BufheSj ) without difturb- 
ing the Texture of thofe Springy parts $ and which may 
prefs as a Weighty but not as a Springs ( of which diftinftioo 
fee Cap.i^,De motu^ Schol.prop pf^p^ iS^p^g J 2(^9 
Now if 5 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 
countcrballaoceit J though its weight be much lels^) be» 
caule admitted with fuch a teafures {ibid,propa'2^i^ ) But 
if only an llo-fpringy Fluid (which prefscrh but as a Weight 
Dot as a Springs) and this defended by the glafs»Tube from 
any other prcffiirej fave that of ifs own weight 5 it will fliJL 
be too weak to force its^ ow.n way 5 till its fiogle weight be 
equivalent to that with which it is to encounter 5 which is, 
notonely the Springy part of the Airj but alfo that Fluid 
Un-fpringy partj which though (becaufe Fluid) it would 
give way to a Springy body preffing through it $ yet not 
tothisFluid, like it felf^ and deflitute of fuch a Spring; 
and is therefore able to keep it up to a much greater, 
height than it could do if un-cjeanfed of Springy Ait : So 
long at leaft as till (bme Springy body be admitted^or fome 
concuflioHj equivalent to it , put it in motion § but being, 
once in motion 3 it will lo continue (as a Bullet impell'd 
by Gun-powder j or an Arrow out of a Bowj) till (topped, 
by fome Pofitive force cqui valeor* 
I do not deny, but that this explication may be fubjeft 
to fome DifBculties and Exceptions 3 but I think, fewer 
than that of allowing the Glafs penetrable by this Subtile, 
matter. But, 
