the flame for a while from it, it be suffered to cool, and when you will
find it as easie to be turned round as at the first.

From all which Experiments it is very evident, that all those Bodies, and
particularly Glass, suffers an Expansion by Heat, and that a very
considerable one, whilst they are in a state of Fusion. For _Fluidity_, as
I elsewhere mention, _being nothing but an effect of very strong and quick
shaking motion, whereby the parts are, as it were, loosened from each
other, and consequently leave an interjacent space or vacuity_; it follows,
that all those shaken Particles must necessarily take up much more room
then when they were at rest, and lay quietly upon each other. And this is
further confirmed by a Pot of _boyling Alabaster_, which will manifestly
rise a sixth or eighth part higher in the Pot, whilst it is boyling, then
it will remain at, both before and after it be boyled. The reason of which
odd _Phænomenon_ (to hint it here only by the way) is this, that there is
in the curious powder of Alabaster, and other calcining Stones, a certain
watery substance, which is so fixt and included with the solid Particles,
that till the heat be very considerable they will not fly away; but after
the heat is increased to such a degree, they break out every way in
vapours, and thereby so shake and loosen the small corpusles of the Powder
from each other, that they become perfectly of the nature of a fluid body,
and one may move a stick to and fro through it, and stir it as easily as
water, and the vapours burst and break out in bubbles just as in boyling
water, and the like; whereas, both before those watery parts are flying
away, and after they are quite gone; that is, before and after it have done
boyling, all those effects cease, and a stick is as difficultly moved to
and fro in it as in sand, or the like. Which Explication I could easily
prove, had I time; but this is not a fit place for it.

To proceed therefore, I say, that the dropping of this expanded Body into