CONTENTS. 



NOTICES AND ABSTRACTS 



MISCELLANEOUS COMMUNICATIONS TO THE SECTIONS. 



MATHEMATICS AND PHYSICS. 

 Mathematics. 



Page 

 Mr J J. Sylvester on the Expressions for the Quotients which appear in 

 tiie application of Sturm's Method to the discovery of the Real Roots of an ^ 

 Equation 



Light, Heat, Electricity, Magnetism. 



Sir David Brewster on the Production of CrystaUine Structure in Crystal- 



hzed Powders by Compression and Traction 



, . on the Optical Pha;nomena and Crystallization of Tour- 

 maline, Titanium, and Quartz within Mica, Amethyst, and Topaz 3 



Mr. A. Claudet on the Angle to be given to BinocularPhotographic Pictures 



for the Stereoscope 



on the Practice of the Daguerreotype '^ 



Professor Helmholtz on the Mixture of Homogeneous Colours o 



Professor Matteucci on the Distribution of Electrical Currents in the Rota- 

 ting Disc of M. Arago 



on the Magnetism of Rotation in Masses of Crystalhzed 



Bismuth 



on the Magnetism of Rotation developed in very small 



Insulated MetalUc Particles 



Professor Phillips on Magnetic Phaenomenain Yorkshire (> 



Professor Pltjcker on Magnetism ' 



Dr. AsTLEY P. Price on a new Photometer -^ 



Mr. W. J. MAcauoRN Rankine's General View of an Oscillatory Theory of 

 Light 



Mr. J. D. SoLLiTT on the Composition and Figurmg of the Specula of Re- 

 flecting Telescopes 



Mr. Cornelius Varley's Description of a Graphic Telescope 10 



