CONTENTS OF N° 131.— Sixth Series. 



LXVI. The Positive Ionization from Hot Salts. By O. W. 

 Eichardson, Professor of Physics, Princeton University .... page 669 



LXVII. Note on the Diffusion of Neon through Hot Quartz. 

 By O. W. Richardson, Professor of Physics, and E. C. Ditto, 

 Fellow in Physics, Princeton University 704 



LXVIII. The Induction- Coil. By E. Taylor Jones, D.Sc., 

 Professor of Physics in the University College of North Wales, 

 Bangor, and D. E. Eoberts, B.Sc, Fellow of the University of 

 Wales. (Plates XII. & XIII.) 706 



LXIX. On the Spectra of the Electrodeless Eing Discharge in 

 certain Gases. By H. Donaldson, B.A. (Camb.), B.Sc. (Lond.), 

 Scholar of Sidney Sussex College, Cambridge 720 



LXX. On the Separation of Spectra in Compound Gases. By 

 G. Stead, B.A., formerly Scholar of Clare College, Cambridge .... 727 



LXXL On the General Problem of Photographic Eeproduction, 

 with suggestions for enhancing Gradation originallv invisible. By 

 Lord Eayleigh, O.M., F.E.S ,- .'. 734 



LXXII. A Belation between Tension and Torsion. By E. A. 

 Houstoun, M.A., D.Sc, Ph.D., Lecturer on Physical Optics in the 

 University of Glasgow 740 



LXXIII. On the Origin of Cometary Bodies and Saturn's 

 Eings. By Henry Wilde, D.Sc, D.C.L., F.E.S. (Plates XIV. 

 & XV.) , 741 



LXXIV. Limitations imposed by Slip and Inertia Terms upon 

 Stokes's Law for the Motion of Spheres through Liquids. By 

 H. D. Arnold, Fellow in Physics in the University of Chicago . . 755 



LXXV. The Mobility of the Positive Ion in Flames. By S. G. 

 Lusby, M.A. (Sydney), Emmanuel College, Cambridge, Barker 

 Graduate Scholar of the University of Sydney 775 



LXXVI. The Mobility of Positive Ions produced from Heated 

 Aluminium Phosphate in Gases at Low Pressures. By George 

 W. Todd, M.Sc, B.A., 1851 Exhibition Scholar of Birmingham 

 University ; Emmanuel College, Cambridge , . . 791 



LXXVII. The Eadioactive Properties of High Temperature 

 Flames. By H. Carter, A.E.C.Sc, B.Sc, Eoyal College of 

 Science, London 805 



LXXVIII. The Mode of Conduction in Gases. By Prof. John 

 S. Townsend 816 



LXXIX. Notices respecting New Books : — Gesammelte Abhandl- 

 ungen von Friedrich Kohlrattsch ; Dr. G. T. Walker's Out- 

 lines of the Theory of Electromagnetism 819 



LXXX. Proceedings of Learned Societies : — 



Geological Society : — Dr. J. D. Falconer on the Geology 



Northern Nigeria 820 



*$* It is requested that all Communications for this Work may be addressed, 

 post-paid, to the Care of Messrs. Taylor and Francis, Printing Office, Red 

 Lion Court, Fleet Street, London. 



