lV CONTENTS OF VOL. XXV. — FOURTH SERIES. 



Page 



Proceedings of the Royal Society : — 



Mr. 11. Mallet on the Earthquake-wave Experiments made 



at Holyhead 146 



Prof. W. Thomson on the Rigidity of the Earth 149 



The Astronomer Royal on the Difference in the Properties 



of Hot-rolled and Cold-rolled Malleable Iron 151 



Prof. Forchhamraer on the Constitution of Sea-water. . . . 152 

 On the Forms of Lenses proper for the Negative Eyepieces of 



Telescopes, by G. B. Airy, Esq., Astronomer Royal 155 



On the Duration of the Combustion of Fuses under different 



Atmospheric Pressures, by M. Dufour 156 



Supplement on the Circumference of the Circle, by Mr. Drach 159 

 On Fresh-water Lakes without Outlet, by Joseph John Murphy. 160 



NUMBER CLXVIL— MARCH. 



Mr. R. Sabine on a New Determination of the Mercury Unit 



of Electrical Resistance 161 



Sir David Brewster on the Pressure Cavities in Topaz, Beryl, 



and Diamond, and their bearing on Geological Theories. ... 174 

 Mr. A. Cay ley on a Theorem relating to a Triangle, Line, and 



Conic 181 



Prof. Challis on a Theory of the Zodiacal Light 183 



Mr. O. D. Allen on Csesium and Rubidium 189 



Messrs. S. W. Johnson and O. D. Allen on the Equivalent and 



Spectrum of Caesium 196 



Prof. Tyndall on Radiation through the Earth's Atmosphere . . 200 

 Mr. A. Cayley on Theorems relating to the Canonic Roots of a 



Binary Quantic of an Odd Order 206 



M. Soret on Ozone 208 



Dr. Atkinson's Chemical Notices from Foreign Journals .... 210 

 Prof. Tyndall's Remarks on an Article entitled "Energy" in 



' Good Words ' 220 



Proceedings of the Royal Society : — 



Mr. W. Hopkins on the Theory of the Motion of Glaciers. 224 



Mr. J. Attfield on the Spectrum of Carbon 233 



Proceedings of the Geological Society : — 



Dr. Bigsby on the Cambrian and Huronian Formations . . 233 

 Mr. O. C. Marsh on the Remains of a new Enaliosaurian 



from the Coal-formation of Nova Scotia 233 



Prof. Huxley's description of Anthrocosaurus 234 



Mr. C. Darwin on the Thickness of the Pampean Formation 



near Buenos Ayres 234 



Mr. C. E. Austin's Geological Notes on the locality in 

 Siberia where Fossil Fishes and Esthcricc were found by 



Dr. Middendorf 234 



Prof. T. 11. Jones on Estheria Middendorjii t . . 234 



