IV CONTENTS OF VOL. XV. SIXTH SERIES. 
Page 
Proceedings of the Geological Society : — 
Prof. F. Dawson Adams on the Structure and Eelations 
of the Laurentian System of Canada , 201 
Rev. W. Howchin on Glacial Beds of Cambrian Age in 
South Australia 202 
Messrs. H. Basedow and J. D. Iliffe on a Formation 
known as " Glacial Beds of Cambrian Age " in South 
Australia ; 203 
Intelligence and Miscellaneous Articles : — 
A Theory of the Displacement of Spectral Lines pro- 
duced by Pressure. — A Correction 204 
Lord Kelvin 204 
JNTJMBEB LXXXVI.— FEBBUABY. 
Messrs. C. E. Mendenhall and L. B. Ingersoll on certain Phe- 
nomena exhibited by Small Particles on a Nernst Glower. . 205 
Prof. E. L. Hancock on the Effect of Combined Stresses on 
the Elastic Properties of Steel. (Plates X. & XI.) 214 
Mr. G. A. Miller on the Groups of Isomorphisms of the 
Groups whose Degree is less than Eight 223 
Mr. Andrew Stephenson on Induced Stability 233 
Mr. L. F. Bichardson on a Freehand Graphic way of deter- 
mining Stream Lines and Equipotentials (Plate XII.) . . 237 
Prof. B. W. "Wood on Anomalous Magnetic Botatory Dis- 
persion of Neodymium. (Plate XIII.) 270 
Prof. B. W. Wood on the Existence of Positive Electrons in 
the Sodium Atom. (Plate XIV.) 274 
Dr. H. Wilde on the Atomic Weight of Badium 280 
Dr. B. A. Houstoun on a New Spectrophotometer of the 
Hiifner Type 282 
Dr. C. G. Barkla on X-Bays and Scattered X-Bays 288 
Prof. W. McF. Orr on the Mixing of Gases. — Bemarks on 
Mr. Burbury's recent Papers 297 
Intelligence and Miscellaneous Articles : — 
On the Focometry of a Concave Lens, by J. A. Tomkins. 300 
NUMBEB LXXXVIL— MABCH. 
Mr. J. Bose-Innes on the Practical Attainment of the Thermo- 
dynamic Scale of Temperature , 3 
Prof. A. H. Bucherer on the Principle of Belativity and on 
the Electromagnetic Mass of the Electron 316 
Mr. T. J. Bowlker on the Factors serving to determine the 
Direction of Sound 318 
