ons, and _there_ is the _Primum mobile_, that one would imagine, if we
were in _Jupiter_, as we do here imagine Ours of 24. hours.

The Discovery is one of the best, that have been yet made in the Heavens;
and those, that hold the Motion of the earth, find in it a full Analogy.
For, _Jupiter_ turning about the Sun, does nevertheless turn about his
_Axis_; and although he be much bigger than the Earth, he does nevertheless
turn much more swiftly than it, since he makes more than two Turns, and a
third part, for its one; and carries with him 4. Moons, as the Earth does
one.

This Observation ought to excite all Curious persons to endeavour the
perfecting of _Optick Glasses_, to the end that it may be discovered,
whether the other _Planets_, as _Mars_, _Venus_ and _Mercury_, about whom
no Moon hath as yet been discovered, do yet turn about their _Axes_, and in
how much time they do so; especially _Mars_, in whom some _Spot_ is
discover'd, and _Venus_, wherein M._Burattini_ hath signified from
_Poland_, he has observ'd Inequalities, as in the Moon.

It will be worth while, to watch for the seeing of _Jupiter_ again this
Spring, that this happy Observation may be confirmed in divers places, and
endeavours used to make new ones.

* * * * *

_An Account of some Books, lately published._

I. _Hydrostatical Paradoxes, made out by New Experiments (for the most part
Physical, and Easie) by the Honourable Robert Boyle._ This Treatise,
promised in _Numb._ 8. of these Papers, is now come forth: And was
occasioned by the perusal of the Learned Monsieur _Paschalls_ Tract, _Of
the AEquilibrium of Liquors_, and of the _Weight of the Air_: Of which two
Subjects, the _latter_ having been more clearly made out in _England_ by
Experiments, which could not be made by Monsieur _Paschal_ and others, that
wanted the advantage of such Engines and Instruments, as have here been
frequently made use {174} off; Our Noble Author insists most upon giving us
his thoughts of the former, _videl._ the _AEquilibrium of Liquors_: Which
Discourse consisting partly of _Conclusions_, and partly of _Experiments_,
the _former_ seem to Him to be almost all of them consonant to the
Principles and Laws of the _Hydrostaticks_; but as for the _latter_, the
Experimental proofs, offered by M. _Paschall_ for his Opinions, are by our
Author esteemed such, that he confesses, he hath no mind to make use of
them: for which he alledges more