xliv Address of Mr J. W. Clark, President, 



March 18, 1839. 



By Sam. Earnskaw, M.A. (Joh.) : On the equilibrium of a system of particles. 



Trans, vn. 97 — 112. 

 By Geo. Biddell Airy, M.A. (Triu.) : On the diurnal changes of the variation 



of the magnetic needle. 



April 22, 1839. 



By Duncan Farquharson Gregory, B.A. (Trin.) : On photogenic drawings. 

 By Professor Sedgwick : On the geology of Cornwall and Devon. 



May 6, 1839. 



By Professor Miller : On the calculation of halos, according to Fraunhofer's 



theory. 

 By Geo. Green : Note on reflection and refraction. Trans, vn. 113 — 120. 

 By Duncan Farquharson Gregory, B.A. (Trin.) : On chemical classification. 



May 20, 1839. 



By Geo. Green, B.A. (Gonv. and Cai.) : On the motion of light through crys- 

 tallised media. Trans, vn. 121 — 140. 



By Dav. Tho. Ansted, B.A. (Jes.) : On the tertiary formations of Switzerland. 

 Trans, vn. 141 — 152. 



By Professor Whewell : An account of observations made with his Anemo- 

 meter since May, 1837. 



November 11, 1839. 



By Professor Whewell : On a new theory of the Tides. Phil. Mag. 1839, 

 ii. 476. 



November 25, 1839. 



By Professor Sedgwick : On the geology of northern Germany, east and west 

 of the Bhine. 



December 9, 1839. 



By Aug. De Morgan, B.A. (Trin.) : On the foundations of Algebra. Trans. 



vn. 173—187. 

 By Dav. Tho. Ansted, B.A. (Jes.) : On the geology of the Transition Rocks in 



the north-east of Bavaria and the Principality of Reuss. 

 By Will. Webster Fisher, M.B. (Down.) : On the malformation of certain 



parts of the nervous system. 



March 2, 1840. 



By Geo. Biddell Airy, M.A. (Trin.) : On a new construction of the Going 

 Fusee, applied in the Northumberland telescope. Trans, vn. 217 — 

 277. 



By Ch. Pritchard, M.A. (Joh.) : On the achromatism of the telescope. 



March 16, 1840. 



By Aug. De Morgan, B.A. (Trin.) : On the foundation of algebra. 

 By Joh. Tozer, M.A. (Gonv. and Cai.) : On some doctrines of Political 

 Economy. Trans, vn. 189 — 196. 



March 30, 1840. 



By Phil. Kelland, M.A. (Qu.) : On the quantity of light intercepted by a 

 grating placed before a lens. Trans, vn. 153 — 171. 



