iv CONTENTS OF VOL. XXXIV. — THIRD SERIES. 



Page 

 The Rev. C. Graves on a system of Triple Algebra, and its 



application to the Geometry of three Dimensions 119 



Prof. Reich on the Repulsive Action of the Pole of a Magnet 



upon Non-magnetic Bodies 127 



Prof. Marcet on the Action of Chloroform on the Sensitive Plant 



{Mimosa pudica) 130 



Mr. J. Cockle's Solution of two Geometrical Problems 132 



Proceedings of the Cambridge Philosophical Society 135 



. Royal Astronomical Society 138 



On the Equivalent of Fluorine, by M. Louyet 150 



Preparation of Iodide of Arsenic 152 



Composition of the Black Yttro-columbite of Ytterby 152 



On Liquid Protoxide of Nitrogen, by M. Dumas 153 



On the Urates, by MM. Allan and Bensch 154 



On the Presence of Copper in the Human Blood, by M. Deschamps 155 



Solubility of Chloride of Silver in Hydrochloric Acid 156 



Formation of Carbonate of Lime from the Neutral Malate of Lime 156 



Journey to Discover the Sources of the Nile 157 



Post-office Regulations 158 



Meteorological Observations for December 1848 159 



Table 160 



NUMBER CCXXVIIL— MARCH. 



Prof. J. D. Forbes on the Classification of Colours 161 



Mr. A. Smith on the Calculation of the Distance of a Shooting 

 Star eclipsed in the Earth's Shadow 179 



Mr. J. Glaisher's Remarks on the Weather during the Quarter 

 ending December 31, 1848 182 



Prof. J. R. Young on the Expression for the remaining roots 

 of a complete Cubic, when one root is found 193 



Mr. J. Locke on Single and Double Vision produced by viewing 

 objects with both eyes ; and on an Optical Illusion with regard 

 to the distance of objects 195 



Mr. T. H. Pratt's Analytical Proof of the Parallelogram of Forces 201 



Mr. N, S. Heineken's Suggestions for rendering a Meridian 

 mark visible at Night 202 



Mr. G. G. Stokes on the ITieory of Sound, in reply to Professor 

 Challis 203 



Mr. T. H. Henry on the Composition of the Gold from Cali- 

 fornia 205 



Sir R. I. Murchison on the Geological Structure of the Alps, 

 Carpathians and Apennines, more especially on the transition 

 from Secondary to Tertiary Types and the existence of vast 

 Eocene Deposits in Southern Europe 207 



Proceedings of the Royal Astronomical Society 216 



■ Cambridge Philosophical Society 225 



