CONTENTS. Vll 



Light. 



Page 



Captain Abney on a Method of showing the Sun's Rotation by Spectrum 



Photography 31 



Mr. A. Vernon Harcourt on a new Unit of Light for Photometry 31 



Lord PiAYLEiGH on the Lower Limit of the Prismatic Spectrum 32 



Mr. J. Traill Taylor on a Binocular Microscope for High Powers 32 



Mr. Silt anus P. Thompson on some new Optical Illusions 32 



on the Relative Apparent Brightness of Objects 



in Binocular and Monocular Vision 32 



Electricity. 



Messrs. W. E. Ayrton and J. Perry on the Viscosity of Dielectrics 33 



on the Contact Theory of Voltaic Action 33 



Mr. Charles Chambers on Magnetic Induction as affecting Observations of 

 the Intensity of the Horizontal Component of the Earth's Magnetic Force 33 



Professor Gr. Carey Foster on the Mode of stating some Elementary Facts 



in Electricity • • • 34 



Mr. W. H. Preece on the Telephone 34 



Mr. S. P. Thompson on an improved Lantern Galvanoscope 37 



Sir W. Thomson on the Effect of Transverse Stress on the Magnetic Suscepti- 

 bility of Iron 37 



Mr. T. T. P. Bruce Warren on the Determination of Temperature-coefficients 

 for insulating Envelopes 37 



Sound. 



Professor H. M'Leod on a new Method of Determining the Vibration-number 



of Tuning-Forks 37 



Ma-. Silvanus P. Thompson on Binaural Audition 37 



Meteorology. 



Dr. Barham on some Relations of Sea and Land Temperature in the South- 

 west of England 38 



Mr. G. Dines on Difference of Rainfall with Elevation 38 



Mr. A. Mallock on the Measurement of the Height of Clouds 38 



Mr. C. Meldrum on the Diurnal Variations of the Barometer and Wind in 



Mauritius i 39 



Mr. John Merrifield on the Meteorology of Plymouth 39 



Miscellaneous. 



Mr. P. Braham, Experiments illustrative of the Flight of Projectiles 40 



Commander Cheyne, Suggestion for a new Polar Expedition, with a proposed 



Route __40 



Captain Evans and Sir W. Thomson on the Tides of Port Louis, Mauritius, 



and Fremantle, Australia 40 



Mr. J. A. Ewing and Dr. J. Gordon MacGregor on the Volumes of 



Solutions 40 



