V On the Vibrations in the Field round a Theoretical Hertzian Oscillator, By 

 KARL PEARSON, F.R.S., and ALICE LEE, B.A., B.Sc., University College, 

 London page!5'J 



VI. OH the Constitution of the Electric Spark, By ARTHUR SCHUSTER, F.R.S., and 



GUSTAV HEMSALECH . . 



VII. On a Quartz Thread Gravity Balance. By RICHARD THRELFALL, lately 



I'rofessor of Physics in the University of Sydney, and JAMES ARTHUR 

 POLUH-K. Demonstrator of Physics in the University of Sydney. Communi- 

 cated by Professor J. J. THOMSON, F.R.S. 215 



VIII. The Colour Sensations in Terms of Luminosity. By Captain W. DE W. 

 ABNEY, C.B., D.CL., F.R.S. 259 



IV Un the Comparative Efficiency as Condensation Nuclei of Positively and Nega- 

 tively Charged Ions. By C. T. R. WILSON, M.A. Communicated by the 

 Meteorological Council 289 



X. On the Resistance to Torsion of Certain Forms of Shafting, with Special Reference 



to the, Effect of Key ways. By L. N. G. FILON, M.A., Research Student of 

 King's College, Cambridge, Fellow of University College, London, 1851 

 Kxhibition Science Research Scholar. Communicated by Professor M. J. M. 

 HILL, F.R.S. 309 



XI. BAKKUIAN LECTURE. The Crystalline Structure of Metals. By J. A. EWINU, 



F.R.S., Professor of Mechanism and Applied Mechanics in the University of 

 Cambridge, and WALTER ROSENHAIN, St. John's College, Cambridge, 1851 

 Exhibition Research Sclwlar, University of Melbourne . .... . . 353 



XII. On the Least Potential Difference Required to Produce discharge through 



Various Gases. By the Hon. R. J. STRUTT, B.A., Scholar of Trinity College, 

 Cambridge. Communicated by Lord RAYLEIGH, F.R.S. 377 



Index to Volume 395 



