(i8) 
bed , is exceeding fmall in refpcft of the whole circumfe- 
rence thereofjand hardly diftinguiftiable by us from a ftreight 
line. 
Concerning the New Comet you mentionj faw it on the 1 1. 
oiFehruary ^ about the 24. deg. Aries ^ with a Northern 
latitude of 24. deg. 40. min» The cloudy weather hath not 
yet permitted me to fee it in 4^dromeda , as others affirm to 
have done. 
Extra^of a Letter , mitten from Paris ^ containing fome 
RefleSiions on part of the precedent Roman Letter. 
As to the Hypothefis oi Ceorg,Dopjenico Cafjini xoncKmg the 
motion of the Comet about the Great Dog in a Circle 5 whofe 
Centre is in a ftreight line drawn from the Earth thorough the 
faid Star , I believe it will fhortly be publifli'd in printj as a 
thought I lighted upon in difcourfing with one of my Friends, 
who did maintainj that it turned about a Centre, becaufc that 
its Perigee had been over againft the Great Dog^ as I had noted 
Inmy Ephemirides, This particular I did long fince declare 
to many of my acquaintance^whereof fome or other will cer- 
tainly do me that right , as to let the world kaow it by the 
Prc/s. I have added an Obiervation, which I find not, that 
SigniorCaJJim hath made5t//2s.that there was ground to think, 
that the Comet of 1652. was the fame with the prefent, feeing 
that, befides the parity of the fwiftnefs of its motion, the Pe- 
r/gee thereof was alfb over againft theGre^^D^^^ if the Obfer- 
vations extant thereof^deceive not. But,to make it out, what 
ground I had for thefe thoughts , I faid, that if they were 
true , the Comet muft needs accomplifh its revolution from 
12. to 12. years, or thereabout. But, feeing it appears not 
by Hiftory, that a Comet hath been feen atthofe determi- 
nate diftances of time, nor that over againft the Perigee of all 
the other Comets,whereof particular obfervations are recor- 
ded, are alwaies found Stars of the firft Magnitude , or fuch 
others, as are very notable, befides other reafons, that might 
be alleged, I (hall not purfue this /peculation 5 but rather 
