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XXIV. An account of observations made with the eight feet 
astronomical circle, at the Observatory of Trinity College, 
Dublin , since the beginning of the year 1818 ,for investigating 
the effects of parallax and aberration on the places of certain 
fixed stars ; also the comparison of these with former observa- 
tions for determining the effects of lunar nutation. By the 
Reverend John Brinkley, D. D. F. R. S. and M. R. I. A. 
Andrews Professor of Astronomy in the University of Dublin. 
Read June 21, 1821. 
The results of the observations which I now beg leave to 
lay before the Royal Society, were instituted with a view of 
discovering, if possible, the source of the differences that 
have existed between the results of former observations 
made here, and of others made at the Royal Observatory at 
Greenwich ; and they will, it is imagined, be found to be 
useful relative to some other important points in astronomy. 
My former observations of certain stars pointed out a de- 
viation of about one second from the mean place, after having 
made all the usual corrections. Mr. Pond’s observations 
pointed out no such deviations. The deviations that I had 
found agreed with the effects of parallax. The observations 
that I have since made, far more numerous than the former, 
concur in exhibiting the same results : in showing deviations 
in certain stars that can be explained by parallax. Every other 
suggested solution of the difficulty appears quite inadequate 
