VI 
Contents. 
page 
12. The Concomitants (including Differential Invariants) of Quadratic Differential 
Forms in Four Variables. By Professor A. B. Forsyth, Sc.D., F.B.S., Hon. 
F.R.S.E., Imperial College of Science and Technology, S.W. Issued 
separately July 4, 1922, . . . . . . . .147 
13. The Magnetic Character of the Quantum. By H. Stanley Allen, M.A., D.Sc. 
Issued separately July 4, 1922, . . . . . . .213 
14. Note on Professor Whittaker’s Quantum Mechanism in the Atom. By Dr R. A. 
Houstoun. Issued separately July 4, 1922, . . . . .221 
15. The Importance of Professor Whittaker’s Atomic Model and of other Atomic 
Models. By Professor W. Peddie. Issued separately July 4, 1922, . . 223 
16. On the Faraday-Tuhe Theory of Electro-Magnetism. By the late William 
Gordon Brown. Gommunicated by Dr C. G. Knott, F.R.S., General Secretary, 
along with a Biographical Note of the Author. Issued separately July 6, 
1922, .......... 225 
17. The Quantum Theory of the Secondary Spectrum of Hydrogen. By John 
Marshall, M.A., D.Sc., University College, Swansea. Issued separately 
July 6, 1922, ......... 247 
18. On the Apjolication of the Gyroscope to the Solution of the “Vertical” Problem 
on Aircraft. Part I. By James Gordon Gray, D.Sc., Cargill Professor of 
Applied Physics in the University of Glasgow ; and Captain J. Gray, 
A.M.I.E.E. (late R.A.F.). Issued separately August 10, 1922, . . 257 
19. Elliptic Expansions. By Mr R. T. A. Innes. Issued separately August 10, 
1922 [Abstract], . . . . . . . . .318 
20. On Self Light, Fatigue, Inhibition, and Recurrent Visual Images. By Professor 
W. Peddie, D.Sc. Issued separately August 10, 1922 [Abstract], . . 319 
21. On the Dominance Ratio. By R. A. Fisher, M.A., Fellow of Gonville and 
Caius College. Communicated by Professor J. Arthur Thomson. Issued 
separately October 16, 1922, ....... 321 
22. Note on a Theorem of Frobenius’ connected with Invariant-Factors. By Sir 
Thomas Muir, F.R.S. Issued separately October 16, 1922, . . . 342 
23. Notes on a Correspondence between the French Academy of Sciences and the 
Royal Society of Edinburgh regarding the Invention of the Pilot Cable 
(Cable Guide). By The General Secretary. Issued separately October 16, 
1922, 348 
24. Chemical Combination and Sir Alfred Ewing’s Magnetic Atom. By Principal 
A. P. Laurie, M.A., D.Sc. Issued separately November 14, 1922, . . 352 
Obituary Notices ; — Sir J. 0. Affleck ; James R. Appleyard ; G. W. W. Barclay ; 
W. S. Bruce ; Alex. Cleghorn ; William Craig ; H. N. Dickson ; Rt. Hon. C. 
Scott Dickson ;yohn Harrison ; Alfred Hill ; Jacobus C. Kapteyn ; Gabriel 
C. Lippman ; Alfred G. Nathorst ; Richard H. Norris ; Sir John Rankine ; 
James Walker ; and Sir G. Sims Woodhead .... 362-395 
