CONTENTS OF VOL. XVIII. 



NUMBER CXIV.— JANUARY, 1841, p^^^ 



Mr. Airy on the Diffraction of an Annular Aperture 1 



Mr. R. Potter's Reply to Mr. Tovey's Remarks on a Paper on 

 the Application of Huyghens's Principle in Physical Optics, 

 inserted in the Lond., Edinb. and Dublin Phil. Mag. for Oc- 

 tober last ; vol. xvii, p. 243 11 



Mr. J. O. Hallivvell on the Impossibility of the Boetian System 

 of Numerical Contractions, and the Alabaldine Notation 



having had a common Origin 13 



Dr. C. Schafhaeutl on Steam considered as a Conductor of Elec- 

 tricity 14 



Mr. W. C. Redfield's Explanation of a Map, showing the Direc- 

 tion of the Wind at Noon, as observed at various Places, in 



the Storm of December 15, 1839 17 



Mr. W. C. Redfield's Remarks relating to the Tornado which 

 visited New Brunswick in the State of New Jersey, June 19, 

 1835, with a Plan and Schedule of the Prostrations observed 



on a Section of its Track 20 



Mr. J. Stenhouse on a new Compound of Chlorine and Cyano- 

 gen 29 



Dr. H. Will on the Composition of Chelidonin and Jervin, ... 32 

 Mr. S. M. Drach on some new and curious numerical Relations 



of the Solar System 37 



Prof. J. C. PoggendoriF on the surprising Intensity of Current 



of the Zinc Iron-circuit, its causes, and some alUed subjects 42 

 Prof. A. Connel's Additional Observations on the Voltaic De- 

 composition of Alcohol 47 



Mr. W. G. Armstrong on the Electricity of Effluent Steam . . 50 



Proceedings of the Royal Society 57 



Lepidomelane — a new Mineral 77 



Hydrotelluric JEther, by M. F. Wohler 78 



Meteorological Observations for November 1840 79 



Meteorological Observations made at the Apartments of the 

 Royal Society by the Assistant Secretary, Mr. lloberton ; 

 by Mr. Thompson at the Garden of the Horticultural Society 

 at Chiswick, near London ; by Mr. Veall at Boston ; and by 

 Mr. Dunbar at Applegarth Manse, Dumfries-shire 80 



NUMBER CXV.— FEBRUARY. 



Mons. A. Rose on the Combination of Hydratcd (the Hydrate 



uf ) Sulphuric Acid with Nitric Oxide 81 



a '2 



