This Chapter is against the _oval Figure of the first Earth_, p. 189.
which the Theorist had asserted, and grounded upon a general Motion of
the Waters, forc’d from the Equinoctial Parts towards the Polar. But
before we proceed to his Objections against this Explication, we must
rectify one Principle. The Exceptor seems to suppose, _p._ 190. that
terrestrial Bodies have a _Nitency inwards or downwards, towards their
central Point_. Whereas the Theorist supposes, that all Bodies moving
round, have, more or less, a Nitency from the Centre of their Motion:
And that ’tis by an external Force that they are prest down, against
their first Inclination or Nitency.
This being premised, we proceed to his Exceptions: Where his first and
grand Quarrel is about the Use of a Word; whether the Motion of the
Water from the middle of the Earth towards the Poles, can be call’d
_defluxus_; seeing those polar Parts, in this supposed Case, were as
high, or higher than the Equinoctial. I think we do not scruple to say
_undæ defluunt ad littora_: Tho’ the Shores be as high, or higher than
the Surface of the Sea. For we often respect, as the Theorist did, the
_middle_ and the _sides_, in the use of that Word; And so, _defluere è
medio ad latera_, is no more than _prolabi ad latera_. But ’tis not
worth the while to contest about a Word; especially seeing ’tis
explained in the second Edition of the Theory, _p._ 186, by adding
_detrusione_: But it would have spoil’d all this Pedantry, and all his
little Triumphs, if he had taken notice of that Explication.
Wherefore setting aside the _Word_, let us consider his _Reasons_
against this Motion of the Waters towards the Poles; which, he says,
could not be, because it would have been an Ascent, not a Descent. We
allow and suppose that. But may not Waters ascend by Force and
Detrusion; when it is the easiest way they can take to free themselves
from that Force, and persevere in their Motion? And this is the Case we
are speaking to. They were impell’d to ascend, or recede from the
Centre, and it was easier for them to ascend laterally, than to ascend
directly: Upon an inclined Plain, than upon a perpendicular one. Why
then should we not suppose that they took that Course? Methinks the
Observator, who seems to be much conversant in the _Cartesian_
Philosophy, might have conceived this Detrusion of the Waters towards
the Poles by the Resistance of the superambient Air, as well as their
flowing towards, and upon the Shores, by the Pressure of the Air under
the Moon. And if the Moon continued always in the same Place, or over
the middle of the Sea, that Posture of the Waters would be always the
same: Though it be an Ascent, both upon the Land and into the Rivers.
And this, methinks, is neither Contradiction, nor Absurdity. But an
Enemy, that is little us’d to Victory, makes a great Noise upon a small
Advantage.
He proceeds now to shew, _p._ 195. that it was improbable that the
Figure of the first Earth should be oval, upon other Considerations. As
first, because of its Position; which would be cross to the Stream of
the Air, that turns it round, or carries it about the Sun: As a Ship, he
says, that stands side-ways against a Stream, cannot sail. But if that
Ship was to turn round upon her Axis, as a Mill-Wheel, and as the Earth
does, what Posture more likely to have such an Effect, than to stand
cross to the Stream that turns it? And the Stream would take more hold
of an oblong Body, than of a round. Then, as to its annual Course, which
he mentions, that’s nothing, but so many Circumvolutions: For in turning
round it is also progressive, as a Cylinder in rowling a Garden: And
three hundred sixty five Circumgyrations compleat its annual Course. So
that this Argument turns wholly against him, and does rather confirm the
oval Figure of the Earth.
His second Argument against the oval Figure of the first Earth, is the
spherical Figure of the present Earth. And how does he prove that? First
from Authorities, _Anaximander_, _Pythagoras_, and _Perminedes_ thought
so. But how does he prove that their asserting the Earth to be _round_,
was not meant in Opposition to its being _plain_; as the _Epicureans_
and the Vulgar would have it? That was the Question _Socrates_ promis’d
himself to be resolv’d in by _Anaxagoras_, _Plat. in Phæd._ πότερεν ἡ γῆ
πλατεῖα ἔπις, ἢ αρογγύλη. _Whether the Earth was flat or round._ And
’tis likely the Dispute was generally understood in that Sense. However
the Theorist hath alledg’d many more Authorities than these, in favour
of the oval Figure of the Earth. For besides _Empedocles_ in particular,
and those whom _Plutarch_ mentions in general, the Philosophy of
_Orpheus_, the _Phœnician_, _Ægyptian_, and _Persian Philosophers_, did
all compare the Earth to an Egg; with respect to its oval external Form,
as well as internal Composition. These you may see fully set down in the
_Theory: Lat. Theor. li. 2. c. 10_. And it had been fair in the Exceptor
to have taken some notice of them, if he would contend in that way of
Authorities. But he has thought fit rather to pass them over wholly in
Silence.
His Reasons, _p._ 197. to prove the Figure of the present Earth to be
spherical, and not oval, are taken first from the Conical Figure of the
Shadow of the Earth, cast upon the Moon. But that cannot make a
Difference sensible to us at this Distance, whether the Body that cast
the Shadow was exactly spherical or oval. His second Reason is _from the
Place of the Waters_; which, he says, would all retire from the Poles to
the Equator, if the polar Parts were higher. But this has been answer’d
before. The same Cause that drives the Waters thither, would make them
keep there: As we should have a perpetual Flood, if the Moon was always
in our Meridian: And whereas he suggests, that by this Means the Sea
should be shallowest under the Poles; which, he says, is against
Experience: We tell him just the contrary, That, according to our
Hypothesis, the Sea should be deepest towards the Poles; which agrees
with Experience. That the Sea should be deepest under the Poles, if it
was of an oval Form, _p._ 186. he may see plainly by his own Scheme, or
by the Theory Scheme: _Theor. Lat. li. 2. c. 5_. So that if his
Observation be true, of an extraordinary Depth of the Ocean in those
Parts, it confirms our Suspicion, that the Sea continues still oval.
Lastly, he urges, _p._ 198. If this Earth was oval, Navigation towards
the Poles would be extremely difficult, if not impossible, because upon
an Ascent. But if there be a continual Draught of Waters from the
Equator towards the Poles, this will ballance the Difficulty, and be
equivalent to a gentle Tide, that carries Ships into the Mouth of a
River, though upon a gradual Ascent.
Thus much we have said in Complacency to the Exceptor. For the Theorist
was not oblig’d to say any Thing in Defence of the oval Form of the
present Earth, seeing he had no where asserted it: It not being
possible, as to what Evidence we have yet, to determine in what Order
the Earth fell, and in what Posture the Ruins lay after their Fall. But
however, to speak my Mind freely upon this Occasion, I am inclinable to
believe, that the Earth is still oval or oblong. What Things the
Anti-theorist hath suggested, will not decide the Controversy; nor, it
may be, any natural History, nor any of those Observations that we have
already. The Surface of the Sea lies more regular than that of the Land,
and therefore I should think that Observations made there would have the
best Effect. I should particularly recommend these two: First, That they
would observe toward the Poles, whether the Sun rise and set, according
to the Rules of a true Globe, or of a Body exactly spherical. Secondly,
That they would observe whether the Degrees of Latitude are of equal
Extent in all the Parts of a Meridian; that is, if the Quantity of Sea
or Land that answers to a Degree in the Heavens, be of equal Extent
towards the Equator as towards the Poles. These two Observations would
go the nearest of any I know, to determine whether the Figure of the
Earth be truly spherical or oblong.