CONTENTS. 
SCIENCE. 
I. The Quantity of Solar Nutation, as affecting the North Polar 
Distances of the fixed Stars deduced from Observation, and 
the Application of this Determination to confirm the Conclusions 
relative to the Parallaxes of certain fixed Stars. By the Rev. 
John Brinkley, D.D. F.R.S. President of the R.1.A. and 
Andrews’ Professor of Astronomy in the ER ry Dublin. 
Read April 1, 1822. eve 
II. On the Application of ri ee of rae i to ee purposes ar 
Practical Navigation. By Alexander Nimmo, Civil Engineer, 
M.R.I. A. &0. Read October 27, 1893. .cccccccccccsentencscee 
III. An Account of a Trigonometrical Survey of Mayo, one of the 
Maritime Counties of Ireland. By William Bald, Civil En- 
gineer, Member of the Geological Society, London, and 
M.R.I. A. Read April 30, 1821. . 
IV. A Letter from William Edgeworth, Esq. Civil ke to 
Alexander Nimmo, Esg. Civil Engineer, M.R.I.A.  Com- 
municated by Mr. Nimmo. Read January 1, 1823. ssscsssssereee 
V. On the General Properties of Algebraic Surfaces. By the Rev. 
Dionysius Lardner, M.R.I. A. Read May 24, 1824. vss 
VI. An investigation of the Lines of Curvature of Ellipsoids, Hyper- 
boloids, and Paraboloids, with a view to the improvement of the 
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