VI CONTENTS OP VOL. XXIX. — FOURTH SERIES. 



Page 

 Mr. T. F. Jamieson on the History of the last Geological 



Changes in Scotland 326 



On a Simple Mode of Determining the Position of an Optic 



Image, by A. Kronig 327 



On a Simplified Method of extracting Indium from the Freiberg 

 Zincblendes, by M. Weselsky 328 



NUMBER CXCVII.— MAY. 



Prof. Challis's Supplementary Considerations relating to the 



Undulatory Theory of Light 329 



Mr. H. G. Madan on the Reversal of the Spectra of Metallic 



Vapours 338 



Mr. D. Forbes on Phosphorite from Spain 340 



Prof. Cayley on the Theory of the Evolute 344 



Prof. Adams on the Application of Screw- Blades as Floats for 



Paddle-wheels 351 



Dr. A. Matthiessen on the Specific Resistance of the Metals in 

 terms of the B. A. Unit (1864) of Electric Resistance, 

 together with some Remarks on the so-called Mercury Unit. 361 



Mr. J. J. Waterston on some Electrical Experiments 370 



Dr. Atkinson's Chemical Notices from Foreign Journals .... 374 

 Mr. J. H. Cotterill on the Equilibrium of Arched Ribs of Uni- 

 form Section 380 



Proceedings of the Royal Society : — 



Messrs. Warren De la Rue, Balfour Stewart, and B.Loewy's 



Researches on Solar Physics 390 



Dr. H. B. Jones on the Passage of Crystalloid Substances 



into the Vascular and Non- Vascular Textures of the Body, 394 

 Prof. A. W. Williamson on the Atomicity of Aluminium. 395 

 Proceedings of the Geological Society : — 



Dr. Haast on the Climate of the Pleistocene epoch of New 



Zealand 398 



Dr. Bryce on the Drift-beds in the Island of Arran 398 



Dr. Bryce on the Occurrence of Beds in the West of Scot- 

 land in the position of the English Crag 399 



The Rev. H. W. Crosskey on the Tellina proximo, Bed near 



Airdrie 399 



Mr. E. R. Lankester on the Mammalian fossils of the Red 



Crag 400 



Prof. Phillips on the Geology of Harrogate 400 



Prof. Harkness on the Lower Silurian Rocks of the South- 



East of Cumberland 401 



Mr. R. Spruce on the Volcanic Tufa of Latacunga 401 



Dr. Blackmore on the Discovery of Flint Implements in 



the Drift at Milford Hill, near Salisbury 401 



Dr. Duncan on the Echinodermata from the South-east 



coast of Arabia, and from Bagh on the Nerbudda .... 402 

 Mr. G. Busk and Dr. H. Falconer on the Fossil contents of 

 the Genista Cave at Windmill Hill, Gibraltar 402 



