VII. Memoir on the Theory of the Partitions of Numbers. Part IV. On the 



Probability that the Successful Candidate, at an Election by Ballot may 

 never at any time have Fewer Votes than the One who is Unsuccessful ; on a 

 Generalization of this Question; and on its Connexion with other Questions of 

 Partition, Permutation, and Combination. By. Major P. A. MAcMAHON, 

 F.R.S. page 153 



VIII. On the Osmotic Pressures of Aqueous Solutions of Calcium Ferrocyanide. 

 Part I. Concentrated Solutions. By the EARL OF BERKELEY, F.R.S., E. G. J. 

 HARTLEY, B.A. (Oxon.), and C. V. BURTON, D.Sc. (Lond.) 177 



IX. The Effect of Pressure upon Arc Spectra. No. 2. Copper, X 4000 to \ 4600. 



B/i W. GEOFFREY DUFFIELD, D.Sc., Honorary Research Fellow in Physics at 

 the University of Manchester, Mackinnon Student of the Royal Society. 

 Communicated by Prof. E. K.UTHERFORD, F.R.S. 205 



X. Results of Magnetic Observations at Stations on the Coasts of the British Isles, 



lit 07. By Commander L. W. P. CHETWYND, R.N., Superintendent of Com- 

 passes. Communicated by Rear-Admiral A. M. FIELD, F.R.S. . . . 227 



XI. The Mobilities of the Ions produced by Rontgen Rays in Gases and Vapours. 



By E. M. WELLISCH, M.A. (Sydney], Emmanuel College, Cambridge; Barker 

 Graduate Scholar of the University of Sydney. Communicated by Prof. Sir 

 J. J. THOMSON, F.R.S. 249 



XII. Determination of the Surface-Tension of Water bi/ the Method of Jet Vibi*ation. 



By N. BOHR, Copenhagen. Communicated by Sir WILLIAM KAMSAY, K.C.B., 

 F.R.S. 281 



XIII. On the Osmotic Pressures of Calcium Ferrocyanide Solutions. Part II. Weak 

 Solutions. By the EARL OF BERKELEY, F.R.S., E. G. J. HARTLEY, B.A. 

 (Oxon.), and J. STEPHENSON, B.Sc. (Lond.) 319 



XIV. On the Spontaneous Crystallisation of Monochloracetic Acid and its Mixtures 

 with Naphthalene. By Principal HENRY A MIERS, F.R.S., and Miss 

 FLORENCE ISAAC, Research Fellow of Somerville College, Oxford . . . 337 



XV. On the Electricity of Rain and its Origin in Thunderstorms. By GEORGE C. 



SIMPSON, D.Sc. Communicated by Dr. GILBERT T. WALKER, F.R.S. . 379 



