i\ CONTENTS OF VOL. VI. FIFTH SERIES. 



Page 



Ammonio-argentic Iodide, by M. Carey Lea '3 



On the Production of Plateau's Film-systems, by A. Terquem. 75 

 On the Magnetic Rotation of the Plane* of Polarization of Light 



under the Influence of the Earth, by Henri Becquerel .... 76 

 On the Crystallization of Silica in the Dry Way, by P. Jlaute- 



feuille 78 



Outlines of the Actinic Theory of Heat, by Prof. C. Puschl. . 79 



NUMBER XXXV.— AUGUST. 



Colonel A. R. Clarke on the Eigure of the Earth 81 



Mr. W. Siemens on Telephony 93 



Erederick Guthrie on Salt Solutions and Attached Water. . . . 105 

 Mr. W. J. Millar on the Transmission of Vocal and other 



Sounds by Wires 115 



Mr. D. J. Blaikley on Brass Wind Instruments as Resonators. 



(Plate I.) . .... 119 



Prof. P. E. Chase on the Nebular Hypothesis. — IX. Radiation 



and Rotation 128 



Prof. W. E. Ayrton on the Electrical Properties of Bees'-wax 



and Lead Chloride. (Plate II.) 132 



Mr. J. Brown on the Theory of A^oltaic Action 142 



Notices respecting New Books : — 



Prof. P. Smyth's Astronomical Observations made at the 

 Royal Observatory, Edinburgh, Vol. XIV., for 1870-77. 145 

 Proceedings of the Geological Society : — 



Dr. J. Geikie on the Glacial Phenomena of the Long 



Island, or Outer Hebrides 146 



Dr. J. Croll on Cataclysmic Theories of Geological Climate 148 

 Mr. T. F. Jamieson on the Distribution of Ice during the 



Glacial Period 149 



Prof. T. G. Bonney on the Serpentine and associated 



Igneous Rocks of the Ayrshire Coast 149 



Dr. H. Hicks on the Metamorphic and overlying Rocks 



in the neighbourhood of Loch Maree, Ross-shire .... 150 

 Mr. W. A. E. Ussher on the Triassic Rocks of Normandy 



and their Environments 152 



Dr. C. P. Sheibner on Eoyaite, an Elaeolitic Syenite occur- 

 ring in Portugal 153 



Photography at the Least-refrangible End of the Solar Spec- 

 trum, by Capt. Abney, R.E., F.R.S 154 



On the Friction of Vapours, by Dr. J. Puluj 157 



On the Depolarization of the Electrodes by the Solutions, by 

 M. Lippmann 159 



