( <4 i ) 
tionary, being then near 20" more Northerly than in 
June, and no lefs than 39 " more Northerly than it 
was in March. From September the Star returned 
towards the South, till it arrived in 'December to 
the lame Situation it was in at that time twelve 
Months, allowing for the Difference of Declination 
on account of the Preceffion of the Equinox. 
This was a fufficient Proof, that the Inftrument 
had not been the Caufe of this apparent Motion of 
the Star, and to find one adequate to fuch an Effect 
ieemed a Difficulty. A Nutation of the Earth’s 
Axis was one of the firff things that offered itfeif 
upon this Occafion, but it was loon found to be 
inlufficient ; for though it might have accounted for 
the change of Declination in y Draconis yet it would 
not at the lame time agree with the Phenomena in 
other Stars ; particularly in a finall onealmoff oppofite 
in right Afcenfion to y Draconis , at about the fame 
Diffance from the North Pole of the Equator : For, 
though this Star feemed to move the fame way, as a 
Nutation of the Earth’s Axis would have made it • 
yet it changing its Declination but about half as 
much as y Draconis in the lame time (as appeared 
upon comparing the Obfervations of both made upon 
the lame Days, at different Seafons of the Year) this 
plainly proved, that the apparent Motion of the 
Stars was not occafioned by a real Nutation, fince if 
that had been the Caufe, the Alteration in both Stars 
would have been near equal. 
The great Regularity of the Obfervations left no 
room to doubt, but that there was fomc regular 
Caufe that produced this unexpected Motion, which 
did not depend on the Uncertainty or Variety of the 
Seafons 
