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CONTENTS 



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SCIENCE. 



Page 



I. On correcting Observations ?nade tvtth Equatorial Instruments. 



By T. R. Robinson, B. D. M. R. I. A. Professor of Astronomy 



at Armagh. Read January 10, 1825 3 



II. Description of a new Air-pump, with an investigation of the limit 



of Exhausting Power in various constructions of that Instrument. 

 By T. R. Robinson, D. D. M. R. I. A. Professor of Astrorwmy 

 at Armagh. Read October ^<?4, 18^5 13 



III. On correcting Errors of the Astronomical Circle by Opposite 

 Readings. By T. R. Robinson, D. D. M. R. I. A. Professor of 

 Astronomy at Armagh. Read December 5, 1825 21 



IV. On the Quantity of the Precession of the Equinoxes, as deter- 

 mined by certain Stars that appear to have no proper motion. 



% The President. Read January 17, 1825 39 



V. Appendix to the foregoing Paper. By Tlie President. Read 



May 22, 1826 53 



VI. Theory of Systems of Rays. By W. R. Hamilton, Andreivs' 

 Professor of Astronomy in the University of' Dublin. Read 

 December 3, 1824 69 



