CONTENTS OF VOL. XXXIX. 



(FOURTH SERIES.) 



NUMBER CCLVIIL— JANUARY 18/0. 



Page 



Canon Moseley on the Mechanical Properties of Ice. (With a 

 Plate.) 1 



Mr. R. Templeton's Remarks suggested by Mr. Douglas's Ac- 

 count of a New Optometer ..:... 9 



Mr. J. A. Phillips's Note on certain Slates, Felsites, and Elvan- 

 ites occurring near Knockmahon in the County of Waterford. 12 



Mr. G. K. Winter's observations of the Corona during the Total 

 Eclipse, August 7, 1869 17 



Prof. Challis on a Mathematical Theory of Tides 18 



Mr. C. Tomlinson on the Motions of certain Liquids on the Sur- 

 face of Water 32 



The Rev. T. K. Abbott's Note on some Propositions in the 

 Theory of the Tides ' 49 



Mr. J. Parnell on Secondary Currents and a new Secondary 

 Battery 52 



Mr. J, N. Lockyer's Reply to some Remarks of Father Secchi 

 on the recent Solar Discoveries 61 



Proceedings of the Royal Society : — 



Mr. H. C. Sorby on Jargonium, a new Elementary Sub- 

 stance associated with Zirconium 65 



Mr. J. P. Harrison on Solar Radiation 70 



On the Laws of Induction. By MM. Jamin and Roger .... 73 



On the Calorific Power of the Lunar Rays, by M. H. Marie-Davy. 78 



NUMBER CCLIX.— FEBRUARY. 



Mr. J. Croll on Ocean-currents. — Part I. Ocean-currents in 

 relation to the Distribution of Heat over the Globe 81 



Prof. R. S. Ball's Note on an Elementary Proof of a Theorem 

 of Lagrange's 107 



Mr. G. K. Winter on the determination of the size of the Wire 

 which, wound upon a Galvanometer or Electromagnet, will 

 produce the maximum magnetic effect in a Circuit of given 

 external resistance. (With a Plate.) 109 



