( ) 
contemplated this Appearance for above sn Hour, v/z. 
from lO:'' to near twelve, and we could not be deceiv’d 
as to its Reality ; but the Slownels of its Motion made 
us at that time conclude that it had none, and that it 
was rather a Neh'ula than a Comet, 
However, fufpedling that it might have fome Motion, 
I attended the next Night, June i ith, at the lame Hours 
and in the fame Company, when with fome Difficulty by 
realbn of the Thicknefs of the Air, we found the two 
little Stars, but the NehuLt could not at that time be feen, 
which we then imputed to the want of a clearer Sky. 
But on Saturda), June i$. the Moon being abfent, and- 
the Air perfedlly clear, we had again a diHind: View 
of the two Stars, with an entire Evidence that there re- 
mained no Footftep or Sign of it, in the place where we 
had firfl; leen this Phanomenon, which we therefore now 
found to be a Comet, and that being far without rhe 
Orb of the. Earth, and in it felf a very fniall Body, it 
appeared only like a little Speck of a Cloud, fuch as, 
would fcarce have been difcerned in an ordinary Tele- 
fcope, much lefs by the naked Eye. 
IX. An Account of ^ooks, I. Joannis Poleni in 
Gymnafio Patavino Phil. Ord. Prof. Sc Scienr. 
Socictatum Rcgalium, qux Londini& Bero- 
lini fuilt, Sodaiis, Ve Motu A^u^e mlxto^ Libri 
duo, ere. 4^®. PataVii 1/17. 
T he Sub}ed;;herfi treated, of not having hitherto 
•fajleii under the Cpnfideration of Mathematical 
Writers, the Learned;iAuchor is obliged to make 
ufe of feverai XermSi which are either wholly new, or at 
r ' ' Isaft 
