IV 



Page 



An Apparatus for testing the Sensitiveness of Safety-lamps. By Frank 

 Clowes, D.Sc. Loud., Professor of Chemistry, University College, Not- 

 tingham 122 



On the Forces, Stresses, and Fluxes of Energy in the Electromagnetic 

 Field. By Oliver Heaviside, F.E.S 126 



Comparison of Simultaneous Magnetic Disturbances at several Observa- 

 tories, and Determination of the Value of the Gaussian Functions for 

 those Observatories. By W. Grylls Adams, D.Sc., F.E.S., Professor 

 of Natural Philosophy in King's College, London 129 



On the Measurement of the Heat produced by Compressing Liquids 

 and Solids. By the late Cosmo Innes Burton, B.Sc., F.C.S., Professor 

 of Chemistry, Polytechnic, Shanghai, and William Marshall, B.Sc., 

 F.C.S 130 



On the Changes evoked in the Circulation and Respiration by Electrical 

 Excitation of the Floor of the 4th Ventricle. By W. G. Spencer, 

 M.S., Assistant- Surgeon to the Westminster Hospital 142 



Contributions to the Chemistry of Chlorophyll. No. IV. By Edward 

 Schunck, F.RS 143 



On some Histological Features and Physiological Properties of the 

 Postoesophageal Nerve Cord of the Crustacea. By W. B. Hardy 144 



List of Presents 144 



Appendix to the Report' of the Kew Committee for the Year ending 

 December 31, 1890 M " 155 



No. 303. November 19, 1891. 



The Thermal Emissivity of Thin Wires in Air. By W. E. Ayrton, 

 F.R.S., and H. Kilgour 166 



On the Time-Relations of the Excursions of the Capillary Electrometer, 

 with a Description of the Method of using it for the Investigation of 

 Electrical Changes of Short Duration. By George J. Burch, B.A. 

 Oxon 172 



On the Collision of Elastic Bodies. By S. H. Burbury, F.R.S 175 



On the Locus of Singular Points and Lines which occur in connexion 

 with the Theory of the Locus of Ultimate Intersections of a System of 

 Surfaces. By M. J. M. Hill, M.A., Sc.D., Professor of Mathematics 

 at University College, London 180 



List of Presents .. 187 



November 26, 1891. 



On Instability of Periodic Motion. By Sir William Thomson, P.R.S 194 



A new Mode of Respiration in the Myriapoda. By F. G. Sinclair (for- 

 merly F. G. Heathcote), M. A., Fellow of the Cambridge Philosophical 

 Society 200 



Further Observations on the Gestation of Indian Rays ; being Natural 

 History Notes from H.M. Indian Marine Survey Steamer "Investi- 



rr," Commander R. F. Hoskyn, R.N., Commanding. Series II. 

 2. By J. Wood-Mason, Superintendent of the Indian Museum and 



