eir _King_ and
_Centre_, as _Planets_ do, making them a kind of _Spurious Planets_, that
emulate the _true_ ones in their Motion almost in all things.

The _Train_, he makes nothing else but the Beams of the Sun, falling on the
head of the Comet, and passing through the same, refracted and reflected.
And amongst his _Observations_ and _Schemes_ of this Comet, there occurs
one, wherein the Tail is _curve_, so seen by him _Decemb._ 11/21. He
assigns the causes why the Trains do so much vary, and shews also, on what
depends their length.

Whether the _same_ Comet returns again, as the Spots in the Sun? and,
whether in the time of great _Conjunctions_ they are more easily generated?
and whether they can be certainly foretold? with several other Inquiries,
he refers for to his _great Book_.

As to _Prognostications_, he somewhat complains, That men do more inquire
what Comets _signifie_, then what they _are_, or how they are generated and
moved; professing himself to be of the mind of those that would have Comets
rather _admired_ then _feared_; there appearing indeed no cogent reason,
why the Author of Nature may not intend them rather as Monitors of his
_Glory_ and _Greatness_, then of his _Anger_ or _Displeasure_; especially
seeing that some very diligent Men (among whom is _Gemma Frisius_) take
notice of as great a number of _good_ as _bad_ Events, consequent to
Comets. _Seneca_ also relating, That that Comet which appeared in his time,
was so happy, that it did _Cometis detrahere infamiam_, it cleared the
credit of Comets, and made People have good thoughts of them.

Having given some Account of what may be look'd for in this _Prodromus_, it
follows, That some also should be rendred of the _Animadversions_ mention'd
to have been made upon the same. This was done by that _Parisian_
Philosopher Monsieur _Auzout_, in a Letter of his to his Country-man
Monsieur _Petit_; in which he strongly conceives, That this {108}
_Prodromus_ contains some mistakes, of which he chiefly singles out one, as
most considerable, in _Hevelius_'s Observation of _Feb._ 8/18, and declares
thereupon, That he, and several very intilligent Astronomers of _France_
and _Italy_ concurring with him therein, (whereas M. _Hevelius_ to him
seems to stand single, as to this particular) found by their Observations,
That this Comet could not, on that day of _February_, be there where M.
_Hevelius_ placeth it, _viz._ In _Prima Arietis_; unless it be said, Tha