CONTENTS OF VOL. X. FIFTH SERIES. V 



Page 

 Messrs. Gee and Stroud on a Modification of Bun sen's Calori- 

 meter 171 



Dr. Eugen Goldstein on the Electric Discharge in Rarefied 



Gases. Part I. (Plate IV.) 173 



The Rev. F.H. Hummel on Evolution by Subtraction 190 



Captain Abney on the Reversal of the Developed Photogra- 

 phic Image.' (Plates V. & VI.) 200 



On the Effects produced bv mixing White with Coloured Eight, 



by Prof. O. N. Rood, of Columbia College 209 



On the Absorption of Radiant Heat by Gases and Vapours, by 



MM. Lecher and Pernter '. 210 



Spectroscopic Researches, by Dr. G. L. Ciamician 212 



On the Action of Hollow in comparison with that of Solid Steel 



Magnets, by W. Holtz 213 



On an Electrodynamical Paradox, by M. Gerard-Lescuyer . . 215 



NUMBER LXIL— OCTOBER. 



Mr. R. H. M. Bosanquet on the Laboratory at St. John's Col- 

 lege, Oxford 217 



Mr. T. Gray on the Electric Resistance of Glass at different 

 Temperatures 226 



Dr. Eugen Goldstein on the Electric Discharge in Rarefied 

 Gases. 



Part II. — On Luminous Phenomena in Gases caused by 

 Electricity '.234 



Mr. R. T. Glazebrook on Mcol's Prism 217 



Prof. R. Clausius on the Employment of the Electrodynamic 

 Potential for the Determination of the Ponderomotive and 

 Electromotive Eorces 255 



Prof. Franz Exner on the Cause of the Production of Electricity 

 by the Contact of Heterogeneous Metals 280 



The Colours of Thin Blowpipe Deposits, by C. H. Koyl, B.A., 

 Student of Physics in Johns Hopkins University 295 



On an Areometer for determining the Density of Solid Bodies, 

 by M. Buguet 297 



Determination of the Specific Gravity of small Fragments of 

 Minerals, by J. Thoulet 297 



On the Law of Magnetoelectric Machines, by J. Joubert .... 298 



On an Acoustic Method of determining Vapour-densities, by 

 H. Goldschmidt 300 



NUMBER LXIIL— NOVEMBER. 



Mr. E. H. Hall on the new Action of Magnetism on a per- 

 manent Electric Current 301 



