CONTENTS OF VOL. XXXVI. SIXTH SERIES. Vll 



Page 

 Prof. J. C. McLennan and H. J. 0. Ireton on Fundamental 

 Frequencies in the Spectra of Various Elements. (Plates 



XIII.-XV.) 461 



Dr. P. A. Lindemann on a G-eometrical Construction for 



rectifying any Arc of a Circle 472 



Prof. Ganesh Prasad on a Peculiarity of the Normal Compo- 

 nent of the Attraction due to certain Surface Distributions. 475 



Mr. L. Southerns on the Double Suspension Mirror 477 



.Notices respecting New Books : — 



Dr. L. Silberstein's A Simplified Method of Tracing Kays 



through any Optical System 486 



Dr. H. Bateman's Differential Equations 487 



Dr. P. J. Moore's A History of Chemistry 487 



Proceedings of the Geological Society : — 



Dr. K,. L. Sherlock on the Geology and Genesis of the 

 Trefriw Pyrites Deposit 488 



Index ... 489 



