CONTENTS. V 



Page 

 Mr. R. Mallet's Note on the Production of Sulphuretted Hy- 

 drogen by the Action of decomposing Animal Matter upon 



Sulphates 235 



New Books : — Dr. Kane's Elements of Chemistry 237 



Proceedings of the Royal Society 240 



Royal Astronomical Society 241 



London Electrical Society 245 



Royal Irish Academy 247 



Action of Sulphuric Acid on Nitrate of Ammonia, by M. Pelouze 25 1 



Preparation of Azotic Gas, by M. Pelouze 252 



Concentration of Nitric Acid by means of Sulphuric Acid, by 



M. Pelouze 252 



Composition of Sugar of Gelatine • • 253 



Lactate of Urea in Urine 253 



Meteorological Observations for July 1841 255 



Table 256 



NUMBER CXXIV.— OCTOBER. 



Mr. Darwin on a remarkable Bar of Sandstone off Pernambuco, 



on the Coast of Brazil 257 



Mr. J. P. Joule on the Heat evolved by Metallic Conductors of 



Electricity, and in the Cells of a Battery during Electrolysis 260 

 Messrs. W.Francis and H. Croft's Notices of the Results of 



the Labours of Continental Chemists (continued) 278 



Mr. J. S. M c Cord's Meteorological Summary of the Weather 



at Montreal, Province of Canada, in Lat. 45° 30' N., Long. 



73° 22' W ; 285 



Prof. Booth's Remarks on a Statement in the Traitd de Me- 



canique of Poisson 287 



Sir W. R. Hamilton on the Focal Lengths and Aberrations of 



a thin Lens of Uniaxal Crystal, bounded by Surfaces which 



are of Revolution about its Axis 289 



Dr. Brett and Mr. J. D. Smith's Experiments on the alleged 



Conversion of Carbon into Silicon 295 



Solution of a Geometrical Problem on the Form of the Black 



Cross in Biaxal Crystals 305 



Mr. R. Hagen on Malic Acid, and the Changes undergone by 



its Salts at High Temperatures 306 



Proceedings of the Geological Society 315 



Royal Astronomical Society ". . . . 325 



London Electrical Society 327 



Chemical Society of London 328 



Preparation of Lactic Acid and Lactates 333 



Preparation of Formic ./Ether 334 



