consists of about 333. dayes: but that the
interval of the time betwixt the times of its beginning to appear equal to
the Stars of the _Sixt Magnitude_, and of its ending to do so, consists of
about 120. dayes: And that its _greatest Appearance_ lasts about 15. dayes:
All which yet he would have understood with some latitude.

This done, he proceeds to the investigation of the Causes of the
Vicissitudes in the Emersion and Dis-appearance of this Star, and having
discoursed, That the apparent Increase and Decrement of every Lucid Body
proceeds _either_ from its changed distance from the Eye of the Observer;
_or_ from its various site and position in respect of him, whereby the
angle of Vision is changed; or from the increase or diminution of the bulk
of the lucid body it self: and having also demonstrated it impossible, that
this Star should move in a _Circle_, or in an _Ellipsis_; and proved it
improbable that it should move in a _Strait Line_, he concludes, that there
can be no other genuin, or at least, no other more probable cause of its
Emersion and Occultation, than this, That the bigger part of that round
Body is obscure and inconspicuous to us, and its lesser part lucid, the
whole Body turning about its own Center, and one Axe; whereby for one
determinate space of time it exhibits its lucid part to the Earth, for
another, subducts it: it not being likely, that fires should be kindled in
the Body of that Star, and that the matter thereof should at certain times
take fire and shine, at other times be extinguisht upon the consumption of
that matter.

_So far of that Star._ As to the other in the _Girdle_ of _Andromeda_, seen
about the beginning of _An._ 1665; he relates, that, when in the end of
1664. the World beheld the then appearing _Comet_, {383} Astronomers
observed also this new _Phaenomenon_, which was called by them _Nebulosa in
Cingulo Andromedae_. Concerning which, he notes, that the same had been
already seen many years before by _Simon Narius_, vid. _An._ 1612. when
with a _Telescope_ he search'd for the _Satellits_ of _Jupiter_, and
observed their motions; alledging for proof hereof, the said _Authors_ own
words, out of his own Book, _De Mundo Joviali_, publisht _An._ 1614. And
farther shews, that it hath formerly appear'd (about 150. years ago) and
been taken notice off by an expert, though Anonymous, Astronomer; whose
words he cites out of a _Manuscript_, brought out of _Holland_ by the
Excellent _J