iv CONTENTS. 



Page 

 Dr. T. Thomson on Pyroxyllc Spirit and its Compounds .... 86 

 Col. R. Wright's Meteorological Observations during a Resi- 

 dence in Colombia between the Years 1820 and 1830 .... 97 

 Mr. Ivory (The Bakerian Lecture) on the Theory of the Astro- 

 nomical Refractions 105 



Mr. Weaver on the Older Stratified Rocks of North Devon, 

 with correlative remarks concerning Transition or Protozoic 



Regions in general 109 



Mr. J.T. Graves on the Functional Symmetry exhibited in the 

 Notation of certain Geometrical Porisms, when they are 

 stated merely with reference to the Arrangement of Points 129' 

 Dr. C. F. Schoenbein's Notice on some peculiar Voltaic Arrange- 

 ments 136 



Mons. A. H. Dumont on the Equivalents of the Cambrian and 

 Silurian Systems in Belgium ; embodied in a "Report on the 

 Progress of the Geological Map of Belgium, during the year 



1838" 146 



Mr. J. F. Goddard on the Polarization of Light by Living 



Animals 152 



Antarctic Expedition — Part VI. of Scientific Memoirs 153 



Separation of Magnesia from Lime and Alumina 154 



Urea ; mode in which it exists in Urine 154 



Lactate of Urea 154 



Subsesquiacetate of Lead, by F. Wohler 155 



Action of Chloride of Tin on Sulphurous Acid, by M. Hering 156 

 Spontaneous Decoloration of Tincture of Litmus, by M. Vogel 157 



Royal Academy of Sciences of Paris 158 



Dr. Barry's Researches in Embryology 159 



Meteorological Observations for June 159 



Table 160 



NUMBER XCV.— SEPTEMBER. 



Dr. M. H. Jacobi on the Method of producing Copies of en- 

 graved Copper-plates by Voltaic Action ; on the supply of 

 mixed Gases for Drummond's Light by Electrolysis ; on the 

 Application of Electro-magnetism as a motive power in Na- 

 vigation, and on Electro-magnetic Currents 161 



Mr. Lubbock on the general Solution of Algebraical Equations 1 65 



Col. R. Wright's Meteorological Observations during a Resi- 

 dence in Colombia between the Years 1820 and 1830 .... 169 



Instructions for the Scientific Expedition to the Antarctic Re- 

 gions, prepared by the President and Council of the Royal 

 Society : Physics and Meteorology ; Meteorological Observa- 

 tions, Magnetical Instruments and Observations 177 



New Books : — Rara Mathematica ; or a Collection of Treatises 

 on the Mathematics and Subjects connected with them : from 

 ancient inedited Manuscripts, edited by J. O. Halliwell, Esq. 242 



