CONTENTS. XV 



Page 



Sir David Brewster on the Connexion between the Solar Spots and Magnetic 



Disturbances 245 



Professor J. D. Everett on a Method of reducing Observations of Underground 



Temperatures 245 



Sir William Rowan Hamilton on an Application of Quaternions to the 



Geometry of Fresnel's Wave-surface 248 



Mr. J. Pope Hennessy on certain Properties of the Powers of Numbers 248 



Mr. Fleeming Jenkin on Gutta Percha as an Insulator at various Temperatures 248 

 on the Retardation of Signals through long Submarine 



Cables 251 



Mr. Cromwell F. Varley on some of the Methods adopted for ascertaining 



the Locality and Nature of Defects in Telegraphic Conductors 252 



Chemistry. 



Mr. James Brazier on the Action of concentrated Sulphuric Acid on Cubebin in 

 relation to the test for Strychnine by Bichromate of Potash and Sulphuric Acid 256 



on Distilled Water 256 



, Notice of Dugong Oil 256 



, Laboratory Memoranda 257 



Mr. Walter Crum on the Ageing of Mordants in Calico Printing 258 



Mr. Thomas Graham on the Molecular Movements of Fluids 259 



Dr. Lyon Playfair on a Symmetrical Arrangement of Oxides and Salts on a 



Common Type 259 



M. Niepce de St. Victor on two new Photochemical Experiments 260 



Geology. 



Mr. James Bryce on the Discovery of Silurian Fossils in the Slates of Down- 

 shire 260 



Professor Thomas H. Huxley on the newly discovered Reptilian Remains 

 from the neighbourhood of Elgin 261 



Rev. Dr. Longmuir on the Section of the Coast between the Girdleness and 

 Dunnottar Castle, Kincardineshire 261 



on the Remains of the Cretaceous Formation in Aber- 

 deenshire 262 



on the Restoration of Pterichthys in ' The Testimony of 



the Rocks' 263 



Rev. James Morrison on Fossil Remains found at Urquhart, near Elgin. 

 (Communicated by the Rev. Dr. Longmuir) 263 



Mr. C. Moore on the supposed Wealden and other Beds near Elgin 264 



on Brachiopoda, and on the Development of the loop in Tere- 



bratula 265 



Professor H. D. Rogers on some Observations on the Parallel Roads of Glenroy 265 

 Rev. Professor Sedgwick on Faults in Cumberland and Lancashire 265 



Botany and Zoology. 



Dr. Dyce on the Identity of Morrhua vulgaris and M. punctata, hitherto described 



as distinct species 265 



Mr. John Moore, Notice of Syrrhaptis paradoxus 265 



Professor Macdonald on the Osteology of Lophius piscatorius 265 



