viii CONTENTS OF VOL. XVIII.— FOURTH SERIES. 



Page 

 Sir R. I. Murchison on the Crystalline Rocks of the North- 

 west Highlands "^^^ 



Suggestions as to the Structure of the Tails of Comets, by the 



Rev. T. W. Webb ^^^ 



On the presence of Vanadium in the Clay of Gentilly, by P. 

 Beauvallet ^^^ 



NUMBER CXXni.— SUPPLEMENT TO VOL. XVIII. 



Dr. BoUey's Critical and Experimental Contribution to the 



Tlieory of Dyeing. (With a Phite.) 481 



Mr. J. Cockle on the Theory of Equations of the Fifth Degree. 508 



Prof. Schonbein on the Polarization of Oxygen 510 



M. R. Bunsen's Blowpipe Experiments 513 



Mr. A. H. Church on Parabenzole, and on the Isomers of Tur- 

 pentine • • ^^'•' 



M. Becquerel on the Luminous Effects produced by the action 



of Light upon Bodies 524 



Proceedings of the Royal Society ; — 



Mr. F. Elefanti on Arithmetical Progressions 532 



Prof. Matteucci on the Electric Properties of Insulating or 



Non-conducting Bodies 533 



Mr. J. A. Wanklyn on the Synthesis of Acetic Acid 534 



Messrs. W. Fairbairn and T. Tate on the Resistance of 

 Glass Globes and Cyliaders to collapse from external 

 pressure, and on the Tensile and Compressive Strength 



of various kinds of Glass 535 



Prof. Brodie on the Atomic Weight of Graphite 539 



Dr. Matthiessen on the Specific Gravity of Alloys 540 



Messrs. F. C, Calvert and,R. Johnson on the Conductivity 



of Mercury and Amalgams 541 



On a simple Apparatus for observing Atmospheric Electricity, 



by Prof. W, Thomson 542 



On the supposed Acid Reaction of Muscular Fibre, by E. du 



Bois-Reymond 544 



Index 547 



PLATES. 



I. II. Illustrative of Prof. Magnus's Hydraulic Researches. 

 III. Ilhistrative of Dr. BoUey's Paper on the Theory of Dyeing. 



