121

Pneumatics.

by the Barometer, of various Kinds

^Structure (LXXXVII).

Since

'' A a &d also from one another, with great Strength,

'' ah ^ Ce P at a Distance, so as sometimes to take up' l hef Ve a ^lllion of Times more Space than they did‘ l Q 0 ° re ln the Form of a dense Body : Which vast'• f e ? lltra C-ti o n and Expansion seems unintelligible by" rrtff 1110 ? t ^ le Particles of Air to be springy and ra-<l Iv) US ’ ot roll’d up like Hoops, or by any otherj 18^7? tb an b y a repulsive Power.”

! A) a ‘, * "at the Particles of Air cannot be thus coil’dj ^ Q die s . ain'd in their elastic State in the Substance ofi Et j ’ ls easy to be strewn from Calculation. Thus,^'the ance > one Cubic Inch of Oak yields 216 Cubicj Now suppose the Pressure of the At-

\ sh., < ij e be on every Square Inch about 15 Ib. (asInch,.. sl re w ) then in order to compress 216 CubicI; 4 s lst to one Cubic Inch, the Weight of 216 Times*t on ° r 3 2 4° which would be the Force to confineWill fe e ‘ lcl1 Side the Cube, which, as it has six Sides,b nd ^> re 6 X 3240 — 19440 Ib, or near twenty thou-?>ie (> f!§ht, to confine this Air in its elastic State in,s not * c ^ ncb 5 supposing it to be all Air; but, as itP° rce will be greater still. This ForceHofVf 19440 Ib. must be exerted in every Cubic^ith a Oaken Tree, which would rend it in Pieces{jut Explosion. It is therefore not to be doubted^tate. ln Bodies does exist in a fixed and unelastic^Wt tbat it is roused, and put into an active re-ly, 7ss te ’ b y means of Fire and Fermentation.

*s?y be he y who would fee the numberless Uses that1 b and” 13 ^ 6 os this important Doctrine of artificialAs 0 the surprising Scenes of Knowledge which it\&&s 11 ln the most abstruse and difficult Parts ofah^^ insult all the latter Part of the invaluableI .mentioned, viz, Dr. Hales’s Vegetable and

st . tatt eal Experiments, some of which we shallI f (E)f a b° >n the Sequel of these Notes.

1 Reas ^*• The Weight of the Air is manifest

I °h and various Experiments. The Particles

“ o Are