VUl CONTENTS. 



Light. 



Ppge 



Mr. J. H. Brown on Refraction and Solar Spots 30 



Professor Cnot'LLEBOis on tlie Action of Quartz on Ultra- Violet Rays SO 



on Tubes Phosphorescent by Friction oG 



Professor J. D. E\Ti:BETT on Focal Lines 30 



on a Difficulty in the Theory of Aberration 80 



on Mirage 30 



Mr. George Forbes on Astronomical Refi'action 30 



Mr. Thomas Gaffikld on the Action of Sunlight on Colourless and Coloured 

 Glass 37 



Mr. Arthur Schuster on the Spectrum of Hydrogen 38 



The Plon. J. W. Strutt on the Application of Photography to copy Diffrac- 

 tion-gratings 39 



Professor James Thomso^^ on Atmospheric Refraction of Inclined Rays, and 

 on the Path of a Level Ray 41 



Dr. T. Ogier Ward on a Phenomenon connected with Diffraction 45 



Colonel Stuart "V^^ortley on the Importance of the Salts of L^ranium in 

 Photography 45 



Professor Ch. V. Zenger on the Velocity of Light in the Chemical Elements, 

 and on their Crystalline Form 40 



Heat. 



Mr. W. F. Barrett on a Condition affecting the Spheroidal State of Liquids, 

 and its probable effect on certain Boiler-Explosions 48 



Dr. William B. Carpenter on the General Oceanic Thermal Circulation . . 48 



Mr. James Dewar on Recent Estimates of Solar Temperature 50 



on the Temperature of the Electric Spark 51 



Dr. J. HoPKiNSON on the Stresses produced in an Elastic Solid by Inequali- 

 ties of Temperature 61 



ElECTBICITT AND MAGNETISM. 



Professor P. G. Tait on Double Neutral Points in Thermoelectric Cun-ents . 52 



Mr. G. K. Winter on the LTse of Electromagnetic instead of Electrostatic 

 Induction in Cable-Signalling 52 



Meteorology. 



Rer. H. A. Boys on Greek Meteorology 53 



M. W. DE FoNViELLE on the Ad-\antages of keeping Records of Physical 

 Phenomena connected with Thunder-storms 55 



Mr. Charles Meldruji on a Periodicity in the Frequency of Cyclones in the 

 ■ Indian Ocean south of the Equator 50 



Mr. Frederick Ernest Sawyer on the Rainfall of Sussex 58 



ACOTTSTICS. 



M. Rudolf Konig on Musical Beats and Resultant Tones 58 



Mr. G. A'^andeleur Lee on the Human Voice as a Musical Instrument .... 58 



