Having a pretty large corner of the Plate for the seven Starrs, void, for
the filling it up, I have added one small _Specimen_ of the appearance of
the parts of the Moon, by describing a small spot of it, which, though
taken notice of, both by the Excellent _Hevelius_, and called _Mons
Olympus_ (though I think somewhat improperly, being rather a vale) and
represented by the Figure X. of the 38. _Scheme_, and also by the Learn’d
_Ricciolus_, who calls it _Hipparchus_, and describes it by the Figure Y,
yet how far short both of them come of the truth, may be somewhat perceiv’d
by the draught, which I have here added of it, in the Figure Z, (which I
drew by a thirty foot Glass, in _October_ 1664. just before the Moon was
half inlightned) but much better by the Reader’s diligently observing it
himself, at a convenient time, with a Glass of that length, and much better
yet with one of threescore foot long, for through these it appears a very
spacious Vale, incompassed with a ridge of Hills, not very high in
comparison of many other in the Moon, nor yet very steep. The Vale it self
ABCD, is much of the figure of a Pear, and from several appearances of it,
seems to be some very fruitful place, that is, to have its surface all
covered over with some kinds of vegetable substances; for in all positions
of the light on it, it seems to give a much fainter reflection then the
more barren tops of the incompassing Hills, and those a much fainter then
divers other cragged, chalky, or rocky Mountains of the Moon. So that I am
not unapt to think, that the Vale may have Vegetables _analogus_ to our
Grass, Shrubs, and Trees; and most of these incompassing Hills may be
covered with so thin a vegetable Coat, as we may observe the Hills with us
to be, such as the short Sheep pasture which covers the Hills of
_Salisbury_ Plains.
Up and down in several parts of this place here describ’d (as there are
multitudes in other places all over the surface of the Moon) may be
perceived several kinds of pits, which are shap’d almost like a dish, some
bigger, some less, some shallower, some deeper, that is, they seem to be a
hollow _Hemisphere_, incompassed with a round rising bank, as if the
substance in the middle had been digg’d up, and thrown on either side.
These seem to me to have been the effects of some motions within the body
of the Moon, _analogus_ to our Earthquakes, by the eruption of which, as it
has thrown up a brim, or ridge, round about, higher then the Ambient
surface of the Moon, so has it left a hole, or depression, in the middle,
proportionably lower; divers places resembling some of these, I have
observ’d here in _England_, on the tops of some Hills, which might have
been caus’d by some Earthquake in the younger dayes of the world. But that
which does most incline me to this belief, is, first, the generality and
diversity of the Magnitude of these pits all over the body of the Moon.
Next, the two experimental wayes, by which I have made a representation of
them.
The first was with a very soft and well temper’d mixture of Tobacco-pipe
clay and Water, into which, if I let fall any heavy body, as a Bullet, it
would throw up the mixture round the place, which for a while would make a
representation, not unlike these of the Moon; but considering the state and
condition of the Moon, there seems not any probability to imagine, that it
should proceed from any cause _analogus_ to this; for it would be difficult
to imagine whence those bodies should come; and next, how the substance of
the Moon should be so soft; but if a Bubble be blown under the surface of
it, and suffer’d to rise, and break; or if a Bullet, or other body, sunk in
it, be pull’d out from it, these departing bodies leave an impression on
the surface of the mixture, exactly like these of the Moon, save that these
also quickly subside and vanish. But the second, and most notable,
representation was, what I observ’d in a pot of boyling Alabaster, for
there that powder being by the eruption of vapours reduc’d to a kind of
fluid consistence, if, whil’st it boyls, it be gently remov’d besides the
fire, the Alabaster presently ceasing to boyl, the whole surface,
especially that where some of the last Bubbles have risen, will appear all
over covered with small pits, exactly shap’d like these of the Moon, and by
holding a lighted Candle in a large dark Room, in divers positions to this
surface, you may exactly represent all the _Phænomena_ of these pits in the
Moon, according as they are more or less inlightned by the Sun.
And that there may have been in the Moon some such motion as this, which
may have made these pits, will seem the more probable, if we suppose it
like our Earth, for the Earthquakes here with us seem to proceed from some
such cause, as the boyling of the pot of Alabaster, there seeming to be
generated in the Earth from some subterraneous fires, or heat, great
quantities of vapours, that is, of expanded aerial substances, which not
presently finding a passage through the ambient parts of the Earth, do, as
they are increased by the supplying and generating principles, and thereby
(having not sufficient room to expand themselves) extreamly condens’d, at
last overpower, with their _elastick_ properties, the resistence of the
incompassing Earth, and lifting it up, or cleaving it, and so shattering of
the parts of the Earth above it, do at length, where they find the parts of
the Earth above them more loose, make their way upwards, and carrying a
great part of the Earth before them, not only raise a small brim round
about the place, out of which they break, but for the most part
considerable high Hills and Mountains, and when they break from under the
Sea, divers times, mountainous Islands; this seems confirm’d by the
_Vulcans_ in several places of the Earth, the mouths of which, for the most
part, are incompassed with a Hill of a considerable height, and the tops of
those Hills, or Mountains, are usually shap’d very much like these pits, or
dishes, of the Moon: Instances of this we have in the descriptions of
_Ætna_ in _Sicily_, of _Hecla_ in _Iceland_, of _Tenerif_ in the
_Canaries_, of the several _Vulcans_ in _New-Spain_, describ’d by _Gage_,
and more especially in the eruption of late years in one of the _Canary_
Islands. In all of which there is not only a considerable high Hill raised
about the mouth of the _Vulcan_, but, like the spots of the Moon, the top
of those Hills are like a dish, or bason. And indeed, if one attentively
consider the nature of the thing, one may find sufficient reason to judge,
that it cannot be otherwise; for these eruptions, whether of fire, or
smoak, alwayes raising great quantities of Earth before them, must
necessarily, by the fall of those parts on either side, raise very
considerable heaps.
Now, both from the figures of them, and from several other circumstances;
these pits in the Moon seem to have been generated much after the same
manner that the holes in Alabaster, and the _Vulcans_ of the Earth are
made. For first, it is not improbable, but that the substance of the Moon
may be very much like that of our Earth, that is, may consist of an earthy,
sandy, or rocky substance, in several of its superficial parts, which parts
being agitated, undermin’d, or heav’d up, by eruptions of vapours, may
naturally be thrown into the same kind of figured holes, as the small dust,
or powder of Alabaster. Next, it is not improbable, but that there may be
generated, within the body of the Moon, divers such kind of internal fires
and heats, as may produce such Exhalations; for since we can plainly enough
discover with a _Telescope_, that there are multitudes of such kind of
eruptions in the body of the Sun it self, which is accounted the most noble
Ætherial body, certainly we need not be much scandaliz’d at such kind of
alterations, or corruptions, in the body of this lower and less
considerable part of the universe, the Moon, which is only secundary, or
attendant, on the bigger, and more considerable body of the Earth. Thirdly,
’tis not unlikely, but that supposing such a sandy or mouldring substance
to be there found, and supposing also a possibility of the generation of
the internal _elastical_ body (whether you will call it air or vapours)
’tis not unlikely, I say, but that there is in the Moon a principle of
gravitation, such as in the Earth. And to make this probable, I think, we
need no better Argument, then the roundness, or globular Figure of the body
of the Moon it self, which we may perceive very plainly by the _Telescope_,
to be (bating the small inequality of the Hills and Vales in it, which are
all of them likewise shap’d, or levelled, as it were, to answer to the
center of the Moons body) perfectly of a Sphærical figure, that is, all the
parts of it are so rang’d (bating the comparatively small ruggedness of the
Hills and Dales) that the outmost bounds of them are equally distant from
the Center of the Moon, and consequently, it is exceedingly probable also,
that they are equidistant from the Center of gravitation; and indeed, the
figure of the superficial parts of the Moon are so exactly shap’d,
according as they should be, supposing it had a gravitating principle as
the Earth has, that even the figure of those parts themselves is of
sufficient efficacy to make the gravitation, and the other two suppositions
probable: so that the other suppositions may be rather prov’d by this
considerable Circumstance, or Observation, then this suppos’d Explication
can by them; for he that shall attentively observe with an excellent
_Telescope_, how all the Circumstances, notable in the shape of the
superficial parts, are, as it were, exactly adapted to suit with such a
principle, will, if he well considers the usual method of Nature in its
other proceedings, find abundant argument to believe it to have really
there also such a principle; for I could never observe, among all the
mountainous or prominent parts of the Moon (whereof there is a huge
variety) that any one part of it was plac’d in such a manner, that if there
should be a gravitating, or attracting principle in the body of the Moon,
it would make that part to fall, or be mov’d out of its visible posture.
Next, the shape and position of the parts is such, that they all seem put
into those very shapes they are in by a gravitating power: For first, there
are but very few clifts, or very steep declivities in the ascent of these
Mountains; for besides those Mountains, which are by _Hevelius_ call’d the
_Apennine_ Mountains, and some other, which seem to border on the Seas of
the Moon, and those only upon one side, as is common also in those Hills
that are here on the Earth; there are very few that seem to have very steep
ascents, but, for the most part, they are made very round, and much
resemble the make of the Hills and Mountains also of the Earth; this may be
partly perceived by the Hills incompassing this Vale, which I have here
describ’d; and as on the Earth also, the middlemost of these Hills seems
the highest, so is it obvious also, through a good _Telescope_, in those of
the Moon; the Vales also in many are much shap’d like those of the Earth,
and I am apt to think, that could we look upon the Earth from the Moon,
with a good _Telescope_, we might easily enough perceive its surface to be
very much like that of the Moon.
Now whereas in this small draught, (as there would be multitudes if the
whole Moon were drawn after this manner) there are several little
Ebullitions, or Dishes, even in the Vales themselves, and in the
incompassing Hills also; this will, from this supposition, (which I have, I
think, upon very good reason taken) be exceeding easily explicable; for, as
I have several times also observ’d, in the surface of Alabaster so ordered,
as I before describ’d, so may the later eruptions of vapours be even in the
middle, or on the edges of the former; and other succeeding these also in
time may be in the middle or edges of these, &c. of which there are
Instances enough in divers parts of the body of the Moon, and by a boyling
pot of Alabaster will be sufficiently exemplifi’d.
To conclude therefore, it being very probable, that the Moon has a
principle of gravitation, it affords an excellent distinguishing Instance
in the search after the cause of gravitation, or attraction, to hint, that
it does not depend upon the diurnal or turbinated motion of the Earth, as
some have somewhat inconsiderately supposed and affirmed it to do; for if
the Moon has an attractive principle, whereby it is not only shap’d round,
but does firmly contain and hold all its parts united, though many of them
seem as loose as the sand on the Earth, and that the Moon is not mov’d
about its Center; then certainly the turbination cannot be the cause of the
attraction of the Earth, and therefore some other principle must be thought
of, that will agree with all the secundary as well as primary Planets. But
this, I confess, is but a probability, and not a demonstration, which (from
any Observation yet made) it seems hardly capable of, though how successful
future indeavours (promoted by the meliorating of Glasses, and observing
particular circumstances) may be in this, or any other, kind, must be with
patience expected.
* * * * *
_FINIS._
* * * * *