LIST OF ILLUSTRATIONS. 
Plates 1 to 5.—Professor R. Threlfall and Mr. J. H. D. Brearley on the Electric 
Properties of Pure Substances.—No. I. The Electrical Properties of Pure 
Sulphur. 
Plate 6.— Mr. C. Barrington Brown and Professor J. W. Judd on the Rubies of 
Burma and Associated Minerals: their Mode of Occurrence, Origin, and 
Metamorphoses. A Contribution to the History of Corundum. 
Plates 7 and 8.—Professor W. C. Roberts-Austen on the Diffusion of Metals. 
Plates 9 and 10.—Mr. M. F. Osmond and Professor Roberts-Austen on the 
Structure of Metals, its Origin and Changes. 
Plates 11 to 14.—Mr. J. Norman Lockyer on the Total Eclipse of the Sun, April 
16, 1893.—Report and Discussion of the Observations relating to Solar Physics. 
