VI CONTENTS OF VOL. IX. — FOURTH SERTES. 



Page 



Mr. J. Wilson's Researches into the Alum Manufacture 413 



Prof. Tyndall on the Polymagnet. (With a Plate.) 425 



Prof. Challis on the Aherration of Light 430 



M. A. Secchi on the Periodical Variations of Terrestrial Mag- 

 netism (coticluded) 432 



Dr. Heddle on Table Spar from the Morne Mountains 452 



Mr. A. H. Church on the Benzole Series. — Part II. Note on 



some Derivatives of Xylole 453 



Mr. G. J. Knox on the Existence of an Electrical iEther 



through Space 457 



Mr. T. H. Henry on a New Compound of Gold and Mercury. 458 



Proceedings of the Royal Society 459 



Researches upon the Magnetic Power of Oxygen, by M. E. Bec- 



querel 474 



On the Alteration of the Volume of some Substances by Heating 



and Fusion, by Hermann Kopp 477 



Recent Appointments 479 



Meteorological Observations for April 1855 479 



Table , . . 480 



NUMBER LXIL— SUPPLEMENT TO VOL. IX. 



M. Verdet on the Optical Properties developed in Transparent 



Bodies by the action of Magnetism. (With a Plate.) 481 



Mr. R. P. Greg on the Crystalline Form of Leucophane .... 510 

 Mr. F. M. Jennings on an Analysis of the Potash and Soda 



Felspars of one of the Dublin Mountains 511 



Mr. A. Cayley on the Porism of the In-and-circumscribed Tri- 

 angle, and on an Irrational Transformation of two Ternary 



Quadratic Forms each into itself 513 



Prof. Pliicker's Contributions to our Knowledge of the Nature 



of the so-called Coercive Force 518 



Prof. W. Thomson on the Dynamical Theory of Heat. — Part V. 

 On the Quantities of Mechanical Energy contained in a Fluid 



in Different States, as to Temperature and Density 523 



Prof. W. Thomson on the Electro-statical Capacity of a Leyden 

 Phial and of a Telegraph Wire insulated in the axis of a cylin- 

 drical Conducting Sheath 531 



Proceedings of the Royal Society 535 



Experiments relating to Endosmose, by M. Lhermite 544 



On the Luminous Coat of the Induction Sparks of Ruhmkorff's 



Apparatus, by T. Du Moncel 546 



On Complementary Colours, by H. Meyer 547 



Index 548 



