CONTENTS. 



NOTICES AND ABSTRACTS OF MISCELLANEOUS 

 COMMUNICATIONS TO THE SECTIONS. 



Page 

 Addendum to the Report of the Transactions of the Sections in 1839 1 



MATHEMATICS AND PHYSICS. 



Professor Sylvester on the relation of Sturm's Auxiliary Functions to the 



roots of an Algebraic Equation 23 



Professor Powell on the Theoretical Computation of Refractive Indices 24 



on the Refraction of Heat 25 



. on certain Points of the Wave-Theory of Light 25 



Rev. Professor Lloyd's Results of some Investigations on the Phsenomena of 



Thin Plates in Polarized Light 26 



on Simultaneous Changes of the Magnetic Elements at 



Different Stations 26 



Rev. T. DuRY on Sea Compasses 27 



Mr. Thomas Hopkins on the Influence of Mountains on Temperature in the 



Winter in certain parts of the Northern Hemisphere 28 



Mr. John Phillips on the Temperature of the Air in York Minster 29 



Mr. JohnPhillips's further Researches on Rain at York, and at Harraby, near 



Carlisle, by Joseph Atkinson, Esq. ; with Remarks by Prof. Phillips 30 



Mr. John Campbell Lees's Notice of a Meteorological Journal for the Year 



1840, kept at Nassau, New Providence 32 



Capt. Hewett's (the late) Letter to Capt. Beaufort, R.N. (referred to in a 



communication by Professor Whewell) 32 



Rev. Henry Moseley on a Machine for Calculating the Numerical Values of 



Definite Integrals 35 



Mr. Fowler on a New Calculating Machine 39 



Sir John F. W. Herschel's Letter on Photographic Engravings 40 



Professor Elie Wartmann on Daltonism 40 



Mr. E. J. Dent on the application of a Coating of Gold by the Electro-metal- 



lurgic process to the Steel Balance-springs of Chronometers 41 



Professor Christie on the Preservation of Magnetic Needles and Bars from 



Oxidation by the Electrotype process 41 



