June 14, 1894. 



Pajja 



The Molecular Surface-energy of the Esters, showing its Variation with 

 Chemical Constitution. By Professor W. Ramsay, Ph.D., F.R.S., and 

 Miss Emily Aston, B.Sc 162 



The Complexity and the Dissociation of the Molecules of Liquids. By 

 Professor W. Ramsay, Ph.D., F.R.S 171 



The Molecular Surface-energy of Mixtures of non-associating Liquids. 

 By Professor W. Ramsay, Ph.D., F.R.S., and Miss Emily Aston, B.Sc. 182 



Flame Spectra at High Temperatures. Part II. The Spectrum of 

 Metallic Manganese, of Alloys of Manganese, and of Compounds con- 

 taining that Element. By W. N. Hartley, F.R.S 192 



Flame Spectra at High Temperatures. Part III. The Spectroscopic 

 Phenomena and Thermo-Chemistry of the Bessemer Process. By 

 "W. N. Hartley, F.R.S., Royal College of Science, Dublin 193 



On a Method for determining the Thermal Conductivity of Metals, 

 with Applications to Copper, Silver, Gold, and Platinum. By James 

 H. Gray, M.A., B.Sc., 1851 Exhibition Scholar, Glasgow University. 199 



List of Presents .. 203 



June 21, 1894. 



Researches on Explosives. Preliminary Note. By Captain Sir A. 

 Noble, K.C.B., F.R.S., M.I.C.E., c 205 



Measurement of Colour produced by Contrast. By Captain W. de W. 

 Abney, C.B., D.C.L., F.R.S 221 



On some Phenomena in Vacuum-tubes. By Sir David Salomons, 

 Bart., M.A., V.-P. lust. Elec. Engrs 229 



On an Instrument for Indicating and Measuring Difference of Phase 

 between E.M.F. and Current in any Alternating Current System. 

 By Major P. Cardew, R.E 250 



On the Difference of Potential that may be established at the Surface 

 of the Ground immediately above and at various Distances from a 

 buried Mass of Metal charged from a High Pressure Electric 

 Light Supply. By Major Cardew, R.E., and Major Bagnold, R.E. .. 252 



On the Viscosity of Water as determined by Mr. J. B. Hannay by 

 means of his Microrheometer. By Robert E. Barnett, A.R.C.S 259 



The Rotation of the Electric Arc. By Alexander Pelham Trotter, B.A. 262 



The Electric Strength of Mixtures of Nitrogen and Hydrogen. By 

 Miss P. G. Fawcett 263 



The Asymmetrical Probability-Curve. By F. Y. Edgeworth, M.A., 

 D.C.L 271 



The Differential Covariants of Twisted Curves, with some Illustrations 

 of the Application to Quartic Curves. By R. F. Gwyther, M.A., 

 Fielden Lecturer in Mathematics, Owens College, Manchester 272 



On the Singular Solutions of Simultaneous Ordinary Differential Equa- 

 tions and the Theory of Congruencies. By A. C. Dixon, M.A., 

 Fellow of Trinity College, Cambridge, Professor of Mathematics in 

 Queen's College, Galway 277 



The Spectrum Changes in Lyrse. Preliminary Note. By J. Norman 

 Lockyer, C.B., F.R.S 278 



