CONTENTS OF K" 2^2.— Fourth Series. 



XXI. On Differential Galvanometers. By Louis Schwendler, 

 Esq page 161 



XXII. On an Electrical Experiment with an Insulated Room. By 

 F. C. Webb, M. Inst. C.E 170 



XXIII. On the Nature of Electricity. By M. E. Edlund 174 



XXIV. On the Hydrodynamical Theory of Attractive and Repul- 

 sive Forces. By Professor Challis, M.A., LL.D., F.R.S 1: 



XXV. On Wave-Theories of Light, Heat, and Electricity. By 

 Henry Hudson, M.D., M.R.I.A 210 



XXVI. On the Law of Gaseous Pressure. By the Hon. J. W. 

 Strutt, M.A., late Fellow of Trinity College, Cambridge 219 



XXVII. Proceedings of Learned Societies : — 

 Royal Society : — Messrs. C. Tomlinson and G. van der 



Mensbrugghe on Supersaturated Saline Solutions. — Part III. 

 On a relation between the Surface-tension of Liquids and the 



Supersaturation of Saline Solutions 223 



Geological Society : — Dr. Oldham and Mr. R. Mallet on 

 some of the Secondary Effects of the Earthquake of the 10th 

 January, 1869, in Cachar 232 



XXVIII. Intelligence and Miscellaneous Articles : — 



On the Influence of Pressure in the Phenomena of Endosmose 

 and Exosmose, by M. Becquerel c 233 



On the Action of Ozone upon Vulcanized Caoutchouc, by Prof. 

 Arthur W. Wright , , 235 



On the instantaneous Oxidation of Alcohol, by M. A. Houzeau. 237 



On some Effects of Slow Actions, produced in the course of a 

 certain number of years, by M. Becquerel 238 



Reply to Professor Clausius, by P. G. Tait 240 



It is requested that all Communications for this Work may be addressed, 

 post-paid, to the Care of Messrs. Taylor and Francis, Printing Office, Red 

 Lion Court, Fleet Street, London. 



