26 
bottom and fides, are quenched, asit were, and made rigid inthat very 
already hardened , will not fuffer the partstofhrink any more from the 
the body of Glafs into a t#ff and clofe texture, after it had been fo ex- 
MicROGRAPHIA, 
of a loofe texture alfo,and,according asthe cold {trikes inwards from the 
pofture wherein the cold findsthem. For the partsof the cru? being 
outward Surface inward ; and though it fhrink a little by reafon of the — 
{mall parcels of fome Aerial fubftances difperfed through the matter of _ 
the Glafs, yet that isnot neer fo much asit appears ( as I juft now hint- 
ed 5) nor if it were, would it be fafficient for to confolidate and condenfe 
ceflively rarified by the heat of the glafs-Furnace. 
But that there may be fuch an expanfion of the aerial fubftance con: | 
tained in thofe little b/ebbs or bubbles inthe body of the drop, this fol- 
Jowing Experiment will make more evident. 
a cae er fos 
Sepang regener ear EI a Di a i. 
iaienmansiapepamn rete sie 
- Takeafmall Glafs-Cane about afoot long, feal up one end of it ber= 
metically,then put in a very {mall bubble of Glafs, almoftof thefhape of 
an Effence-viol with the open mouth towards the fealed end, thendraw 
out the other end of the Pipe very {mall,and fillthe whole Cylinder with 
water, then fet this Tube by the Fire tillthe Water begin to boyl, and 
the Air in the bubble be in good part rarified and driven out, thenby 
fucking atthe fmalling Pipe, more of the Air or vapoursin the bubble 
may be fuck’d out, fo that it may fink tothe bottom; when itis funkto 
the bottom,in the flame of a Candle,or Lamp,nip up theflender Pipeand — 
let it cool: whereupon it is obvious to obferve, firft, thatthe Water by 
degrees will fubfide and fhrink into much lefsroom: Next, that the Air 
or vapours in the Glafs will expand themfelves fo, as to buoyupthe little 
Glaf: Thirdly, that all about the infide of the Glafs-pipe there willap- _ 
pear an infinite number of {mall bubbles,which as the Water growscolder — 
and colder will fwell bigger and bigger, and many of them buoy them- _ 
felves wp and break at the top. at Vio ssiddul 4 
From this Difeeding of the heat in Glafs drops.that is, by the quenching _ 
or cooling Irradiations propagated from the Surface upwards and in- _ 
wards, by the lines CT, CT, DT, DE,@c. the bubbles inthe drop — 
havefoom to expand themfelves a little, and the parts of the Glafs con= 
tratt themfelves; but this operation being too quick for the {luggifh parts — 
of the Glafs, the contraction is performed very unequally and irregularly, 
and thereby the Particles of the Glafgare bent, fome one way, and fome 
another, yet foas that moft of them ‘draw towards the Pithor middle 
TEEE, or rather from that outward: fo that they cannot extricate ons 2 
unbend themfelves, till fome part of T EE E be brokenand loofened, — 
for all the parts about that are placed in the:manner of an Arch, and fo © 
till their hold at T EE E be loofened they cannot fly afunder, but up- 
hold, and fhelter, and fix each other much like the ftones in a Vault, 
where each ftone does concurre to the ftability of the whole Fabrick, — 
and no one {tone canbe taken away but the whole Arch falls.And where 
foever any of thofe radiating wedges DT D, &c. are removed, which 
are the component parts of this:Arch,the wholeFabrick prefently fallsto 
pleces $ 
