unless we allow a
_Turbinated_ motion of _Mars_ upon its Center: Which, if such there be,
from the Observations made _March_ 21. 22. and 23. we may guess it to be
once or twice in about 24. hours unless it may have some kind of
_Librating_ motion; which seems not so likely. Now, whether certainly so or
not, I shall endeavour, as oft as I have opportunity, further to observe.

[Illustration]

A particular direction to the _Figures_ mentioned in the precedent
discourse.

A. _March _3^{d.} 00^{h.} 20^{m.}_ in the morning: the Air having many
{242} inflecting parts dispersed up and down in it; by the _Wheel
Barometer_, heavy,_

B. _Another Scheme, which I drew from my Observation, about 10. minutes
after, the same morning. Both these were observed with a very deep
Eye-glass._

C. _March_ 10^{d.} 00^{h.} 20^{m.} _in the morning: the Air heavy and
inflective. Use was made of a shallow or ordinary Charge._

D. _March_ 10^{d.} 3^{h.} 00^m _in the Morning; the Air very heavy and
Inflective, which made it glare and radiate, and be more confused, than
about 3. hours before. A shallow Charge._

E. _March_ 21^{d.} 91/2^{h.} _post merid; the Air light (in weight) and
clear, without inflecting parts; the Face appear'd most distinctly of this
Forme. A shallow Charge._

F. _March_ 21^{d.} 113/4^{h.} _post merid; the Air continuing very light and
clear, without inflecting vapours. A shallow Charge._

G. _March_ 22^{d.} 81/2^{h.} _post mer. the Air clear, with few inflecting
veins in it, and indifferent light. A shallow Charge._

H. _March_ 23^{d.} 91/2^{h.} _post mer. the Air pretty light, but moist, and
somewhat thick and hazy, but seem'd to have but few veins, or inflecting
parts._

I. _March_ 28^{d.} 3^{h.} _p. m. much the same kind of Air with that of
March 23; light, moist, and a little hazy, with some very few veins._

* * * * *

_Observations made in _Italy_, confirming the former, and withall fixing
the _Period_ of the Revolution of _Mars_._

These Observations we shall summarily present the Curious in these parts
with, as they were lately presented (by Letter from his Excellency the
Ambassadour of _Venice_, now residing at the Court of _France_) to the
_Royal Society_, in some printed sheets of Paper, entituled, _MARTIS, circa
Axem proprium Revolubilis, Observationes, BONONIAE a JO. DOMINICO CASSINO
habitae;_ come to hand _June_ 3. 1666.

In these Papers the Excellent _Cassini_ a