. CONTENTS OF VOL. XIX. 



NUMBER CXXL— JULY, 1841. 



Page 



Prof. Daniell on the Spontaneous Evolution of Sulphuretted 

 Hydrogen in the Waters of the Western Coast of Africa, 



and of other Localities 1 



Abstract of recent Researches on the Quantity of Heat evolved 

 ' in Chemical Combination, particularly those of MM. Dulong 



and Hess 19 



Mr. W. G. Armstrong's Further Experiments on the Electri- 

 city of Effluent Steam '. 25 



Mr. Weaver on Irish Tin Ore 27 



Mr. Martyn J. Roberts on the Analogy between the Pheno- 

 mena of the Electric and Nervous Influences 31 



Mr. J. Stenhouse on the Action of Peroxide of Lead on Cin- 



namic Acid and on Salicine 38 



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



the Labours of Continental Chemists (continued) 41 



Mr. W. R. Birt on a Paraselene witnessed on May 6, 1841 . . 50 

 Dr. J. Sutherland on the Polarization of the Chemical Rays of 



Light 52 



The Rev. J. Park on an Improvement in the Air-pump 59 



Mr. W. J. Henwoodon Mr. J. Scott Russell's Remarks on the 

 Temperature of most effective Condensation (of Steam) . . 60 



Mr. L. F. Menabrea on Cavendish's Experiment 62 



The Rev. J. Challis's Reply to Mr. Airy's additional Remarks 

 on Professor Challis's Investigation of the Resistance of the 



Air to an Oscillating Sphere 63 



Prof. Forbes's Researches on Heat. — Fourth Series. On the 

 Effect of the Mechanical Texture of Screens on the im- 

 mediate transmission of Radiant Heat 69 



New Books : — Lubbock on the Theory of the Moon, and on the 

 Perturbations of the Planets. Part IV. — Woodhouse's Essay 



on Single Vision 81 



Proceedings of the London Electrical Society 87 



London Institution 88 



Two Letters on Calotype Photogenic Drawing, from H. F. 



Talbot, Esq., F.R.S., to the Editor of the Literary Gazette 88 

 Process for obtaining the Hydrobromic and Hydriodic Acids, 



by Dr. R. M. Glover 92 



New Alum, by Dr. Mohr 93 



On the supposed Hydrate of Phosphorus, by M. Marchand . . 93 



Nitro- Saccharic Acid 94 



Geology and Mineralogy of Engineering 95 



Meteorological Observations for May 1841 95 



a 2 



