viii CONTENTS OF VOL. XXIII. — FOUttTII SERIES. 



Page 

 M. A. de la Rive on the Aurora? Borcales, and on Phenomena 



which attend them 546 



Proceedings of the Royal Society : — 



Mr. P. Griess on a New Class of Organic Bases, in which 



Nitrogen is substituted for Hydrogen 553 



Mr. P. Griess on the Reproduction of Non-nitrogenous 



Acids from Amidic Acids 555 



Proceedings of the Geological Society : — • 



Mr. J. W. Kirkby on some remains of Chiton from the 



Mountain Limestone of Yorkshire 558 



Prof. Owen on some Fossil Reptilia from the Coal-measures 



of the South Joggins, Nova Scotia 558 



The Rev. W. B. Clarke on the occurrence of Mesozoic and 



Permian Faunas in Eastern Australia 558 



Mr. A. Tylor on the Foot-print of an Iguanodon lately 



found at Hastings 559 



On the Connexion between Earthquakes and Magnetic Disturb- 

 ances, by Dr. J. Lamont 559 



On the Freezing of Saline Solutions, by Dr. Riidorff 560 



On the Composition of Minerals containing Niobium, by Prof. 



H. Rose 561 



Index 564 



ERRATA IN VOL. XXII. 



Page 200, line 9 from top, /or 0° =100 read 0° = 226. 



PLATES. 



I. Illustrative of M. G. Kirchhoff's Paper on the Relation of the Lateral 

 Contraction to the Longitudinal Expansion in Rods of Spring Steel, 

 and of MM. A n Breda and Logeman's Paper on the Repulsion of 

 a rectilinear Electrical Current on itself. 



II. Illustrative of Prof. Regnault's Papers on the Specific Heat of some 

 Simple Bodies; on new A pparatus for determining the Densities 

 of Gases and Vapours; and on a new Pyrometer. 



III. Illustrative of Mr. A. Church's Paper on the Structure and Composi- 



tion of Beekite. 



IV. Illustrative of Colonel Sir H. James and Captain Clarke's Paper on 



Projections for Maps. 



V. Illustrative of Mr. J. J. Waterston's Paper on Solar Radiation. 



