CONTENTS OF VOL. XV. 



(FIFTH SEEIES). 



NUMBEE XCL— JANUAEY 1883. 



Page 

 Prof. E. Edlund's Eesearches on the Passage of Electricity 



through Earefied Air 1 



Mr. E. Sabine on aWedge-and-Diaphragm Photometer .... 22 

 M. Hermann W. Yogel on Lockyer's Theory of Dissociation . . 28 

 Mr. S. Bidwell on the Electrical Eesistanee of Selenium Cells 31 

 Mr. W. E. Browne on Central Forces and the Conservation of 



Energy 35 



Mr. A. P. Laurie on the Eelations between the Heats of Com- 

 bination of the Elements and their Atomic "Weights 42 



Mr. J. LeConte on the Amount of Carbon Dioxide in the 



Atmosphere 46 



Mr. J. LeConte on the Apparent Attractions and Eepulsions 



of Small Floating Bodies. (Plate I.) 47 



Notices respecting New Books : — 



Eev. O. Fisher's Physics of the Earth's Crust 56 



Mr. E. Ballard's Solution of the Pyramid Problem .... 59 

 Mr. E. A. Peacock's Saturated Steam the Motive Power 

 in Yolcanoes and Earthquakes ; great Importance of 



Electricity 60 



Proceedings of the Geological Society : — 



Mr. T. M. Eeade on the Drift-beds of the North-west of 



England and North Wales 60 



Mr. T. W. E. David on the Evidences of Glacial Action 

 in South Brecknockshire and East Glamorganshire . . 62 



Eev. A. Irving on the Mechanics of Glaciers 63 



Eev. A. Irving on the Origin of Valley-Lakes 65 



On the Exactness of the Measurements made with Mercurial 



Thermometers, by J. M. Crafts 66 



Theoretic Interpretation of the Effect produced by a Thin 

 Layer of Oil spread out at the Surface of the Sea to calm the 

 Agitation of the Waves, by M. van der Mensbrugghe .... 68 



On the Electrification of the Air, by M. Mascart 70 



The Displacements and Deformations of Electric Sparks by 

 Electrostatic Actions, by Aug. Eighi 72 



