(M5) 
thefecondFaceofil/^r/, he could not fee it the 14. and i d. of 
April. • 
From all which Obfervations he Judges it to be evidentjthi^ 
the Period of this Planets Revolution is notpcrform'din the 
fpace of 1 2. hours 20^ nainutes, but in about 24 hours 40 mi- 
nutes^ more exadly to be determined by comparing diftant 
Obfervations : And that thofe who affirm the former,muft have 
been deceived by not well diftinguifliing the two Faces^ but 
that having ften the fecond, taken it for the firft; 
All which he concludes with this Advertifement, that, whe?i 
he defines the time of the Revolution Mars, he does not fpeak 
of its M^^« Revolution^ but onely of that, which he ob^erv'd, 
whilft Mars was oppofite to the Sun; which is the iiorteft of a!L 
7ht Figures of the Principal Obfervations^ reprefented in 
the Book, here difcourfed of., may be feen in the annexed 
Scheme ; videL 
One of the Faces of Mars, as S, Caflini ohferved it March 
XflM,) 1 6 ($6. in the Evenings with a Glafs of 24 Palmes, 
Tu.The other Face^as he jaw it Febr.^. inth Evening. 
M. The fir f: Face, as J.Campani [aw at Rome^ March |. 1 666. 
in the Evming, with a Glafs of 50 Falmes. 
K. The fecund Face,, as the fame Campani obfervd it March ||» 
in the Eveninf^, 
\ 0= The Figure oj Mars^ as it was feen at R.ome by a Telcfiope of 
Divini of 45 P^/w^/,March fl 
' P. The Figure of the faid Planet^ as it was feen the fame day arid 
hour at Bononia CafEni; being that of the fecond Face^ 
.'■ Sonm Obfervations 
Lately made at London concerning the 
Planet Jupiter. 
Ihefe, as they weremade^ fo they were imparted^ by Mr. 
Hoo\,^s follows : 
A. 1666. lune 2(5. between 5. and 4. of the Clock in the 
morniog, I obferved the Body of Jupiter through a 60 foot- 
glafs, and found the apparent Diameter of it through the Tube,, 
to- be fomewhat more than 2. degreesj that is^ about four 
times 
