CONTENTS OF VOL. XII. 



(FOURTH SERIES.) 



NUMBER LXXVI.— JULY 1856. 



Page 



Prof. Powell on the Demonstration of Fresnel's Formulas for 



Reflected and Refracted Light ; and their Applications 1 



Mr. A. Cayley on the Cones which pass through a given Curve 



of the Third Order in Space 20 



Mr. H. M. Witt on a peculiar Power possessed by Porous 

 Media (Sand and Charcoal) of removing Matter from Solu- 

 tion in Water 23 



Prof. Tyndall's Comparative View of the Cleavage of Crystals 



and Slate Rocks 35 



Prof. W. H. Miller on the Form of an Alloy of Bismuth 48 



The Rev. S. Haughton on the Density of the Earth, deduced 

 from the Experiments of the Astronomer Royal, in Harton 



Coal-pit 50 



Dr. Atkinson's Chemical Notices from Foreign Journals. .... 51 



Proceedings of the Royal Society 59 



Geological Society 68 



On the Absorption of Heat by Decomposition, by Dr. Woods. . 74 



On Heat as the Equivalent of Work, by M. Hoppe 75 



Explosive Action of Sodium on Water, by F. W. Griffin, Ph.D. 78 



Meteorological Observations for May 1856 79 



Meteorological Observations made by Mr. Thompson at the 

 Garden of the Horticultural Society at Chiswick, near 

 London; by Mr. Veall at Boston; and by the Rev. C. 

 Clouston at Sandwick Manse, Orkney 80 



NUMBER LXXVII.— AUGUST. 



Prof. Clausius on a modified Form of the second Fundamental 

 Theorem in the Mechanical Theory of Heat 81 



Prof. H. Hennessy on the Influence of the Earth's Internal 

 Structure on the Length of the Day 99 



Mr. W. J. M. Rankine on Heat as the Equivalent of Work . . 103 



Prof. Powell on the Demonstration of Fresnel's Formulas for 

 Reflected and Refracted Light ; and their Applications. — 

 Part II 104 



