ugh to be perceived. In many places also are _Vulcans_,
that seem big enough to be distinguish't, especially in the shadow: And
when Fire lights upon Forrests of great extent, or upon Towns, it can
hardly be doubted, but these Luminous Objects would appear either in an
Ecclipse of the Earth, or when such parts of the Earth are not illuminated
by the Sun. But yet, I know no man, who hath observed such things in the
_Moon_; and one may be rationally assured that no _Vulcans_ are there, or
that none of them burn at this time. This it is (_so he goes on_) which all
Curious men, that have good _Telescopes_, ought well to attend; and I doubt
not; but, if we had a very particular _Map_ of the _Moon_, as I had
designed to make one with a _Topography_, as it were, of all the
considerable places therein, that We or our Posterity would find some
changes in Her. And if the _Mapps_ of the _Moon_ of _Hevelius_, _Divini_,
and _Riccioli_ are exact, I can say, that I have seen there some places
considerable enough, where _they_ put _parts that are clear_, whereas _I_
there see _dark ones_. 'Tis true that if there be _Seas_ in the _Moon_, it
can hardly fall out otherwise, than it doth upon our _Earth_, where
_Alluvium's_ are made in some places, and the Sea gains upon the Land in
others. _I say_, if those Spots we see in the _Moon_, are Seas, as most
believe them to be; whereas I have many reasons, that make me doubt,
whether they be so; of which I shall speak elsewhere. And I have sometimes
thought, whether it might not be, that all the Seas of the _Moon_, if there
must be Seas, were on the side of the other _Hemisphere_, and that for this
cause it might be that the _Moon_ turns not upon its _Axis_, as our
_Earth_, {122} wherein the Lands and Seas are, as it were, ballanced: That
thence also may proceed the non-appearance of any Clouds raised there, or
of any Vapors considerable enough to be seen, as there are raised upon this
Earth; and that this absence of Vapors is perhaps the cause, that no
_Crepuscle_ is there, as it seems there is none, my selfe at least not
having hitherto been able to discerne any mark thereof: For, me thinks, it
is not to be doubted, but that the reputed Citizens of the _Moon_ might see
our _Crepuscle_, since we see, that the same is without comparison
stronger, than the _Light_ afforded us by the _Moon_, even when she is
_full_; for, a little after Sun-set, when we receive no more than the
_first_ Light of the _S