IV CONTENTS OF VOL. XXX. FOURTH SERIES. 



Page 

 Prof. Poggendorff on a new form of the Mercurial Air-pump. . 129 

 M. P. Desains on the Emission of Luminous Radiation at a Red 



Heat 136 



Mr. D. Forbes on the Mineralogy of South America 139 



Proceedings of the Royal Society : — 



Mr. A. J. Ellis on the Corrections for Latitude and Tempe- 

 rature in Barometric Hypsometry, with an improved form 



of Laplace's formula . 144 



Proceedings of the Geological Society : — 



Mr. G. F. Matthew on the Azoic and Palaeozoic Rocks of 



Southern New Brunswick 158 



Dr. Sandberger's Results of Geological Observations in 



Baden and Franconia , 158 



Dr. Rubidge on the Changes rendered necessary in the 

 Geological Map of South Africa, by recent discoveries 



of fossils 159 



On an Electrical Induction Machine, by M. Holtz 159 



On the Optical Properties developed in different kinds of Glass 

 by the passage of an Electric Discharge, by M. A. De la 

 Rive 160 



NUMBER CCII.— SEPTEMBER. 



Sir David Brewster's Observations on the Polarization of the 

 Atmosphere, made at St. Andrews in 1841, 1842, 1843, 

 1844, and 1845. (With a Plate.) 161 



Dr. W. von Bezold on the Electrical Behaviour of Solid Insu- 

 lators 181 



Mr. P. E. Chase on the Influence of Gravity on Magnetic De- 

 clination 185 



Mr. J. J. Waterston on the Thermal Action in the Wire of a 

 Voltaic Circuit as indicating that the current-force operates 

 on the surface of a metallic conductor only, and not through 

 its substance „ 191 



M. R. Thalen on the Determination of the Limit of Elasticity 

 in Metals. (With a Plate.) 194 



Prof. Challis's Supplementary Researches in Hydrodynamics. 

 —Part I 207 



Mr. R. Templeton on a Method of Utilizing Compact Loga- 

 rithmic Tables 221 



Prof. Davy on the Action of Nitric and Nitrous Acids on the 

 Sulphocyanides 228 



Prof. Sylvester's Note to the Editors of the Philosophical Ma- 

 gazine and Journal 232 



Notices respecting New Books : — Mr. R. A. Proctor on Saturn 

 and its System 233 



Results of Blasting Experiments made with Nitroglycerine at 

 Vieille-Montagne Mine, by M. Nabel .... t 236 



