IN D E X to YOL. LXXVIII. (A) Adsorption and occlusion (Travers), 9. Affinity constants of amphoteric electrolytes (Johnston), 82. Air, examination of lighter constituents of (Coates), 479. Allen (H. S.) The Photo-electric Fatigue of Zinc, 483. Allman, George Johnston, Obituary Notice of, xii. a-rays from polonium, production of secondary rays by (Logeman), 212. a-rays from Radio-Tellurium, electrostatic deviation of (Huff), 77. Ammonia, physical constants of (Perman and Davies), 28. Armstrong (H. E.) The Origin of Osmotic Effects, 264. Barometric variations of long duration over large areas (Lockyer), 43. Bell, Sir Isaac Lowthian, Obituary Notice of, xiv. Berkeley (Earl of) and Hartley (E. G. J.) On the Osmotic Pressures of some Concentrated Aqueous Solutions, 68. Berry (A. J.) Results of gauging High Vacua by the Evaporation Test, 456. Bronson (H. L.) The Effect of Temperature on the Activity of Radium and its Trans­ formation Products, 494. Buchner (E. H.) The Composition of Thorianite, and the Relative Radio-activity of its Constituents, 385. Calcium as an absorbent of gases (Soddy), 429. Caldwell (R. J.) Studies of the Processes operative in Solutions.—Part I. The Sucro- clastic Action of Acids as influenced by Salts and Non-electrolytes, 272. Campbell (A.) On the Electric Inductive Capacities of Dry Paper and of Solid Cellulose, 196. Coates (J. E.) An Examination of the Lighter Constituents of Air, 479. Cotton, hygroscopic action of (Masson and Richards), 412. Critical Temperatures, behaviour of certain substances at (Travers and Usher), 247. Crookes (Sir W.) On the Ultra-violet Spectrum of Ytterbium, 154. Cumming (A. C.) The Affinity Constants of Amphoteric Electrolytes. II.—Methyl Derivatives of Ortho- and Meta-aminobenzoic Acids, 103. Davies (J. H.) Vapour-pressure of Liquid Ammonia and Determination of its Boiling Point, 41. (See also Perman and Davies.) Distribution, law of, when one phase possesses mechanical rigidity (Travers), 9. Durrant (R. G.) Experimental Evidence of Ionic Migration in the Natural Diffusion of Acids and of Salts.—Phenomena in the Diffusion of Electrolytes, 342. Dyson (F. W.) Determinations of Wave-length from Spectra obtained at the Total Solar Eclipses of 1900, 1901 and 1905, 240. Eclipses, 1900—1905, wave-lengths in spectra obtained at (Dyson), 240. Electrolytes, amphoteric, affinity constants of (Johnston), 82 ; (Cumming), 103 ; (Walker), 140. VOL. LXXVIII.— A. 2 M 502 Electrolytes, ionic migration phenomena in diffusion of (Durrant), 342. Explosives, researches on (Noble), 218. Fleming (J. A.) A Note on the Theory of Directive Antennae or Unsymmetrical Hertzian Oscillators, 1. Foam-structure of matter (Quincke), 60. Gas, effect of change of temperature and pressure (Perman and Davies), 28. Gifford (J. W.) The Refractive Indices of Water and of Sea-water, 406. Gravity, dependence of, on temperature (Southerns), 392. Harker (J. A.) On the “ Kew” Scale of Temperature and its Relation to the Inter­ national Hydrogen Scale, 225. Hartley (E. G. J.) See Berkeley and Hartley. Hartley (W. N.) Note on the Continuous Rays observed in the Spark Spectra of Metalloids and some Metals, 403. Hertzian oscillators, unsymmetrical, theory of (Fleming), 1. Huff (W. B.) The Electrostatic Deviation of a-Rays from Radio-Tellurium, 77. Hull (G. F.) An Investigation of the Influence of Electric Fields on Spectral Lines : Preliminary Note, 80. Hygroscopic action of cotton (Masson and Richards), 412. Inductive capacities of dry paper and solid cellulose (Campbell), 196. Ionic migration in diffusion of acids and salts (Durrant), 342. Ionic velocities in air at different temperatures (Phillips), 167. Ionisation produced by hot platinum (Richardson), 192. Johnston (J.) The Affinity Constants of Amphoteric Electrolytes. I.—Methyl Deriva­ tives of Para-aminobenzoic Acid and of Glycine, 82. Joly, Charles Jasper, Obituary Notice of, lxii. Kew scale of temperature and international hydrogen scale (Harker), 225. Lenox-Conyngham (G. P.) An Account of the Pendulum Observations connecting Kew and Greenwich Observatories made in 1903, 241. Liquid to solid state, transition from (Quincke), 60. Lockyer (W. J. S.) Barometric Variations of Long Duration over Large Areas, 43. Logeman (W. H.) Note on the Production of Secondary Rays by a-Rays from Polonium, 212. McClean, Frank, Obituary Notice of, xix. Maclaurin (R. C.) A Numerical Examination of the Optical Properties of Thin Metallic Plates, 296. MacMahon (P. A.) The Theory of the Compositions of Numbers.—Part II, 459. Mallock (A.) The Relation between Breaking Stress and Extension in Tensile Tests of Steel, 472. , . Masson (O.) and Richards (E. S.) On the Hygroscopic Action of Cotton, 412. Mees (C. E. K.) See Sheppard and Mees. Mersey, tidal regime of, as affected by dredgings (Shoolbred), 161 Metallic plates, optical properties of (Maclaurin), 296. 503 Metalloids, continuous rays in spark spectra of (Hartley), 403. Micro-manometer, on a compensated (Roberts), 410. Noble (Sir A.) Researches on Explosives.—Part IY, 218. Numbers, theory of compositions of (MacMahon), 459. Obituary Notices of Fellows Deceased, i. Occlusion and adsorption (Travers), 9. Optical properties of thin metallic plates (Maclaurin), 296. Osmotic effects, origin of (Armstrong), 264. Osmotic pressures of aqueous solutions (Berkeley and Hartley), 68. Pendulum observations connecting Kew and Greenwich (Lenox-Conyngham), 241. Perman (E. P.) and Davies (J. H.) Some Physical Constants of Ammonia : a Study of the Effect of Change of Temperature and Pressure on an Easily Condensible Gas, 28. Phillips (P.) Ionic Yelocities in Air at Different Temperatures, 167. Photo-electric fatigue of zinc (Allen), 483. Photographic processes, theory of.—Latent image and its destruction (Sheppard and Mees), 461. Polonium, production of secondary rays by a-rays from (Logeman), 212. Quincke (G.) The Transition from the Liquid to the Solid State and the Foam-structure of Matter, 60. Radio-activity of thorianite (Buchner), 385. Radio-tellurium, a-rays from (Huff), 77. Radium, action of, on gelatin (Rudge), 380; ----- and its products, effect of temperature on activity of (Bronson), 494; ----- distribution in earth’s crust (Strutt), 150. Refractive indices of water and sea-water (Gifford), 406. Richards (E. S.) See Masson and Richards. Richardson (O. W.) The Ionisation produced by Hot Platinum in Different Gases, 192. Roberts (B. J. P.) On a Compensated Micro-manometer, 410. Rudge (W. A. D.) The Action of Radium and certain other Salts on Gelatin, 380, Saponification, method for determining velocities of (Walker), 157. Self-induction in iron cylinder, effects of (Wilson), 22. Shaw (W. N.) An Apparent Periodicity in the Yield of Wheat for Eastern England, 1885 to 1905, 69. Sheppard (S. E.) and Mees (C. E. K.) The Theory of Photographic Processes. Part III.—The Latent Image and its Destruction, 461. Shoolbred (J. N.) The Tidal Regime of the River Mersey, as affected by the Recent Dredgings at the Bar in Liverpool Bay, 161. Snelus, George James, Obituary Notice of, lx. Soddy (F.) Calcium as an Absorbent of Gases for the Production of High Yacua and Spectroscopic Research, 429. Solutions, processes operative in (Caldwell), 272. Southerns (L.) Experimental Investigation as to Dependence of Gravity on Temperature, 392. Spark spectra of metalloids, continuous rays in (Hartley), 403. Spectral lines, influence of electric fields on (Hull), 80. 504 Steel, breaking stress and extension in tensile tests (Mallock), 472. Strutt (R. J.) On the Distribution of Radium in the Earth’s Crust, 150. Struve, Otto, Obituary Notice of, liv. Sucroclastic action of acids as influenced by salts, etc. (Caldwell), 272. Sugar, hydrolysis of (Caldwell), 272. Temperature, Kew scale of, and international hydrogen scale (Harker), 225. Tliorianite, composition and radio-activity of (Buchner), 385. Tidal regime of the Mersey and dredgings in Liverpool Bay (Shoolbred), 161. Travers (M. W.) The Law of Distribution in the Case in which one of the Phases possesses Mechanical Rigidity : Adsorption and Occlusion, 9 ; ----- and Usher (F. L.) On the Behaviour of certain Substances at their Critical Temperatures, 247. Usher (F. L.) See Travers and Usher. Vacua, calcium as absorbent for production of (Soddy), 429 ; -----gauged by evaporation test (Berry), 456. Walker (Jas.) A Method for determining Velocities of Saponification, 157; ----- The Affinity Constants of Amphoteric Electrolytes. III.—Methylated Amino-acids, 140. Wharton, Sir William, Obituary Notice of, xliv. Wheat, apparent periodicity in yield of, for Eastern England (Shaw), 69. Williamson, Alexander William, Obituary Notice of, xxiv. Wilson, Sir Charles W., Obituary Notice of, xlix. Wilson (Ernest). Effects of Self-induction in an Iron Cylinder, 22. Wislicenus, Johannes, Obittiary Notice of, iii. Young (S.) Note on Opalescence in Fluids near the Critical Temperature, 262. Ytterbium, ultra-violet spectrum of (Crookes), 154. Zinc, photo-electric fatigue of (Allen), 483. END OF THE SEVENTY-EIGHTH VOLUME (SERIES a ). H arrison and Sons, Printers in Ordinary to His Majesty, St. Martin’s Lane. OBITUARY NOTICES OF FELLOWS DECEASED. CONTENTS. PAGE J ohannes W islicenus iii Geo roe J ohnston A llman xii Sir I saac Lowthian Bell xiv F rank McClean xix A lexander W illiam W illiamson {with plate) xxiv Sir W illiam W harton ... xliv Sir Charles W. W ilson xlix Otto Struve liv George J ames Snelus ... lx Charles J asper J oly ... Ixii , j. iii JOHANNES WISLICENUS. 1835—1902. There are few branches of science so indelibly associated