vi " CONTENTS. 



Page. 



John Thomas Graves on the Theory of Exponential Functions. 52S 



JoHK S. Russell's Notice of the Reduction of an anomalous Fact 

 in Hydrodynamics, and of a new Law of the Resistance of 

 Fluids to the Motion of Floating Bodies 531 



Eaton Hodokinson on the Collision of imperfectly Elastic Bodies 534 



The Rev. James Challis's Theoretical Explanations of some Facts 

 relating to the Composition of the Colours of the Spectrum . . 514. 



The Rev. Professor Powell on the Achromatism of the Eye ; in 

 Continuation of a Paper in the last Volume of the British Asso- 

 ciation Reports 548 



The Rev. Professor Powell on the Theory of the Dispersion of 

 Light by the Hypothesis of Undulations 549 



The Rev. Professor Powell on the Repulsion excited between 

 Surfaces at minute distances by the Action of Heat 549 



The Rev. William Whewell's Suggestions respecting Sir John 

 Herschel's Remarks on the Theory of the Absorption of Light 

 by coloured Media 550 



The Rev. T. R. Robinson on the Visibility of the Moon in Total 

 Eclipses 552 



Professor Miller's Account of some Observations made for the 

 purpose of determining the Positions of the Axes of Optical 

 Elasticity in oblique prismatical Crystals 556 



R. Addams's Account of a new Phaenomenon of sonorous Inter- 

 ference 557 



Professor Lloyd's Account of Magnetical Observations in Ireland, 

 and of a new Method of observing the Dip and the Force with 

 the same Instrument 557 



Sir Thomas M. Brisbane on an apparent Anomaly in the Measure 

 of Rain 560 



Professor Phillips's Second Report of the Result of Twelve 

 Months' Experiments on the Quantities of Rain falling at different 

 Elevations above the Surface of the Ground at York, under- 

 taken at the request of the Association by William Gray, Jun., 

 and Professor Phillips, F.R.S. F.G.S., Secretaries of the York- 

 shire Philosophical Society 560 



Luke Howard on the difference of the Quantity of Rain at different 

 Heights above the Surface of the neighbouring Ground 563 



Professor Stevelly's Attempt to connect some of the best-known 

 Phaenomena of Meteorology with established Physical Principles 564 



Professor Christie — Extract of a Letter to Professor Forbes . . 566 



Lieut.-Col. Sykes's Notes on mean Temperatures in India 567 



The Rev. J. Hailstone on a peculiar Oscillation of the Barometer 569 



H. H. Watson on the use of Leslie's Hygrometer with a new Scale 569 



Alexander J. Adie's Account of Experiments on the Expansion 

 of Stone by the Application of Heat 569 



