CONTENTS OF VOL. XXXV. 



(FIFTH SEEIES). 



NUMBEE CCXIL— JANUAEY 1893. 



Prof. E. Threlfall on the Electrical Properties of Pure Sub- 

 stances. — Part I. The Preparation of Pure Nitrogen and 

 attempts to Condense it. (Plate I.) 1 



Messrs. Heinrich Eubens and Benj. W. Snow on the Eefrac- 

 tion of Eays of Great Wave-length in Eock-salt, Sylvite, 

 and Fluorite. (Plate II.) 35 



Mr. Walter Bailj on the Construction of a Colour Map .... 46 



Mr. E. H. M. Bosanquet on Mountain-Sickness ; and Power 

 and Endurance . .. r , 47 



Dr. William Pole: Further Data on Colour-blindness. — 

 No. ILL.. 52 



Prof. F. T. Edgeworth on a New Method of treating Corre- 

 lated Averages 63 



Mr. Fernando Sanford on a necessarv Modification of Ohm's 

 Law. (Plate III.) " 65 



Messrs. Eimington and Wythe Smith on Experiments in 

 Electric and Magnetic Fields, Constant and Varying. 

 (Plate 1Y.) 68 



Notices respecting New Books : — 



Mr. J. C. Sawer's Odorographia 73 



Proceedings of the Geological Society : — 



Prof. M. E. Wadsworth on the Geology of the Iron, 



Gold, and Copper Districts of Michigan 74 



Mr. H. M. Becher on the Gold-quartz Deposits of 



Pahang (Malay Peninsula) ...... 75 



Mr. F. D. Power on the Pambula Gold-deposits 76 



An Electrolytic Theory of Dielectrics, by A. P. Chattock . . 76 



On a Chemical Actinometer, by H. Eigollot 77 



On the Attraction of two Plates separated by a Dielectric, 

 by M. Julien Lefevre 78 



Investigation of the Properties of Amorphous Boron, by 

 H. Moissan 80 



