W CONTENTS. 



Page 

 Meteorological Observations made at the Apartments of the 

 Royal Society by the Assistant Secretary, Mr. Roberton; 

 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 96 



NUMBER CXXIL— AUGUST. 



Mr. Grove on some Electro-Nitrogurets 97 



Dr. Faraday on some supposed forms of Lightning 104 



Mr. Martyn J. Roberts's Remarks on Professor Poggendorff's 



Paper on the Intensity of Current of the Zinc-iron Circuit 106 

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

 Effect of the Mechanical Texture of Screens on the imme- 

 diate transmssion of Radiant Heat 109 



Prof. Booth on a new Theorem in the Calculus of Finite Dif- 

 ferences, with its Application to the Development of the Co- 

 sine of a Multiple Arc in descending Powers of the Cosine of 



the Simple Arc 125 



Mr. T. Hopkins on the Formation of the Cumulus Cloud .... 135 

 Mr. Airy's Reply to Prof. Challis on the Investigation of the 



Resistance of the Air to an Oscillating Sphere ; . 143 



Mr. Potter on the Phenomena of Diffraction in the Centre of 

 the Shadow of a Circular Disc, placed before a luminous 



Point, as exhibited by Experiment 151 



Proceedings of the Royal Society 156 



Geological Society 168 



Meteorological Observations for June 1841 175 



Table 176 



NUMBER CXXIIL— SEPTEMBER. 



Prof.Miller on the Form and Optical Constants of Anhydrite. .177 



Abstract of recent Researches on the quantity of Heat evolved 

 in Chemical Combination, particularly those of MM. Dulong, 

 Hess and Andrews. (continued) 178 



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

 Labours of Continental Chemists (continued) 184 



Prof. Draper on some Analogies between the Phenomena of 

 the Chemical Rays, and those of Radiant Heat 195 



Prof. Redtenbacher of Prague, and Liebig of Giessen on the 

 Atomic Weight of Carbon 210 



The Rev. J. Challis on a new Method of Investigating the Re- 

 sistance of the Air to an Oscillating Sphere 229 



