r 4° 3 
full of the Comparifon of our bcft modern Obfer- 
vations, with fuch as were formerly made with any 
tolerable Degree of Exadnefs ; there appears to have 
been a real Change in the Pofirion of fome of the fixed 
Stars, with refpect to each other j and fuch, as 
feeins independent of any Morion in our own Syf- 
teni, and can only be referred to fomc Motion in 
the Stars themfclves, Ar 61 nr us affords a firong Proof 
of this: for if its p re fell t Declination be compared 
with its Place, as determined either by Tycho or 
Flamfteed \ the Difference will be found to be much 
greater, than what can be fufpectcd to arife from 
the Uncertainty of their Obfervations. 
It is rcafonable to exped, that other Inftanccs of 
the like kind mutt: alio occur among the great Num- 
ber of the vifibie Stars : becaufe their relative Po- 
rtions may be alter'd by various means. For if our 
own Solar Syttem be conceived to change its Place, 
with refpect to Abfolute Space ; this might, in Pro- 
cels of Time, occafion an apparent Change in the 
angular Diftances of the fixed Stars; and in fuch a 
Cafe, the Places of the nearett Stars being more af- 
fected, than of thofe that are very remote,- rheir re- 
lative Pofitions might feem to alter ; tho* the Stars 
themlelves were really immoveable. And on the 
other Hand, if our own Syttem be at Rett, and any of 
the Stars really in Motion, this might likewife vary 
their apparent Pofitions - y and the more fo, the nearer 
they are to us, or the fwifter their Motions are, or 
the more proper the Direction of the Motion is, to 
be rendered perceptible by us. Since then the Re- 
lative Places of the Stars may be changed from fuch 
a Variety of Cauies, conftdering that amazing Di- 
c fU.ncc 
