CONTENTS OF VOL. XIII. 



(FIFTH SERIES). 



NUMBER LXXVHL— JANUARY 1882. 



Page 

 Prof. E. Edlund on the Electrical Resistance of Vacuum .... 1 

 Mr. L. "Wright on some Spiral Figures observable in Crystals, 



illustrating the Relation of their Optic Axes. (Plate I.) . . 20 

 Mr. T. Bayley on the Connexion between the Atomic Weight 

 and the Chemical and Physical Properties of Elements. 



(Plate II.) 26 



Dr. E. L. Nichols on the Electrical Resistance and the Coeffi- 

 cient of Expansion of Incandescent Platinum 38 



Sir James Cockle on New Transformations of Ordinals .... 44 

 M. C. Cellerier on the Distribution of the Molecular Velocities 



in Gases 47 



Prof. S. P. Thompson on the Beats of Mistuned Consonances . . 68 

 Proceedings of the Geological Society : — 



Mr. T. Gray on the Elasticity- and Strength-constants 



of Japanese Rocks 70 



Mr. J. D. Kendall on the Glacial Deposits of West Cum- 

 berland 71 



On the Determination of the Illuminating-power of the Simple 



Radiations, by MM. A. Crova and Lagarde 72 



The Photodynamic Paraboloid, by Pliny Earle Chase, LL.D. 74 

 On the Action of Cold upon the Galvanic Arc, by D. Tommasi. 75 

 On the Variations of the Resistance of Electrical Machines 

 with their Velocity, by M. E. Lacoine 76 



NUMBER LXXIX.— FEBRUARY. 



Mr. C. V. Boys on Integrating and other Apparatus for the 

 Measurement of Mechanical and Electrical Forces. (Plates 

 TJ1., IV.) 77 



Mr. H. Barfield on the Experimental Comparison of Coeffi- 

 cients of Induction 95 



Mr. J. LeConte on Sound-Shadows in Water 98 



Dr. T. Carnelley on Chemical Symmetry, or the Influence of 

 Atomic Arrangement on the Physical Properties of Com- 

 pounds 112 



