As if, for example, we suppose the Circle ABCD,
in the fourth Figure, to represent a drop
of water, Quick-silver, or the like, included
with the Air or the like, which supposing there
were no gravity at all in either of the fluids,
or that the contained and containing
were of the same weight, would be equally
comprest into an exactly spherical body
(the ambient fluid forcing equally against
every side of it.) But supposing either a greater
gravity in the included, by reason whereof the
parts of it being prest from A towards
B, and thereby the whole put into motion,
and that motion being hindred by the
resistance of the subjacent parts of
the ambient, the globular Figure ADBC
will be deprest into the Elliptico-spherical,
EGFH. For the side A is detruded
to E by the Gravity, and B to
F by the resistance of the subjacent
medium: and therefore C must necessarily
be thrust to G; and D to H.
Or else, supposing a greater gravity in the
ambient, by whose more then ordinary pressure
against the under side of the included globule; B
will be forced to F, and by its resistance
of the motion upwards, the side A will
be deprest to E, and therefore C
being thrust to G and D to H;
the globular Figure by this means also will
be made an Elliptico-spherical. Next if
a fluid be included partly with one, and partly
with another fluid, it will be found to be shaped
diversly, according to the proportion of the
gravity and incongruity of the 3 fluids
one to another: As in the second Figure,
let the upper MMM be Air, the middle
LMNO be common Oyl, the lower OOO
be Water, the Oyl will be form’d,
not into a spherical Figure, such as is represented
by the pricked Line, but into such a Figure
as LMNO, whose side LMN will be of a flatter Elliptical
Figure, by reason of the great disproportion between
the Gravity of Oyl and Air, and
the side LOM of a rounder, because of the smaller
difference between the weight of Oyl and Water.
Lastly, The globular Figure will be changed,
if the ambient be partly fluid and partly
solid. And here the termination of the
incompassed fluid towards the incompassing is
shap’d according to the proportion of the congruity
or incongruity of the fluids to the solids,
and of the gravity and incongruity of the fluids
one to another. As suppose the subjacent medium
that hinders an included fluids descent, be a solid,
as let KI, in the fourth Figure, represent the
smooth superficies of a Table; EGFH, a parcel
of running Mercury; the side GFH will be more
flatted, according to the proportion of the incongruity
of the Mercury and Air to the Wood,
and of the gravity of Mercury and Air
one to another; The side GEH will likewise be a little
more deprest by reason the subjacent parts are now
at rest, which were before in motion.