IV CONTENTS OF VOL. IX.— FIFTH SERIES. 



Mr. J. A. Fleming on a new Form of Besistance-Balance 



adapted for comparing Standard Coils. (Plate IV.) 109 



Messrs. Perry and Ayrton on a Dispersion- Photometer .... 117 



Mr. P. E. Nipher on the Electric Light 1 20 



"W. H. Walenn on Unitation. — IX. Practical Bemarks thereon, 



together with Examples . 121 



Dr. O. J. Lodge on Intermittent Currents and the Theory of 



the Induction-balance < . 123 



Dr. W. Flight on two new Amalgams, and a Specimen of 



Native Gold . . 146 



Notices respecting New Books : — 



Dr. G. Lunge's Theoretical and Practical Treatise on the 

 Manufacture of Sulphuric Acid and Alkali, with the col- 

 lateral Branches 148 



M. Ed. Beyer on the Mode of Formation of the Granitic 

 Effusions of Neudeck and Carlsbad, and the History 

 of the Stanniferous Bock-formation in the Erzgebirge 149 

 M. Ed. Beyer on the Structure of the Volcanos of Bo- 

 hemia 149 



Proceedings of the Geological Society : — 



The Bev. J. F. Blake on the Portland Bocks of England 150 

 Mr. D. Mackintosh on the Correlation of the Drift-depo- 

 sits of the N.W. of England with those of the Midland 



and Eastern Counties 151 



Mr. F. Butley on the Schistose Volcanic Bocks occurring 



on the west of Dartmoor 152 



On Magnets, by 0. A. S. Pihl , 153, 



On the Thermal Absorbent and Emissive Powers of Flames, and 

 on the Temperature of the Voltaic Arc, Extract of a Letter 



from Fr. Bosetti to A. Cornu 154 



On some new Luminous Tubes, by M. Treve 155 



On Thomson's Galvanometer, by A. Gaifde 156 



Tin-mining in Banka and Bilitong 156 



NITMBEE LV.— MABCH. 



Dr. J. Kerr on Measurements and Law in Electro-optics .... 157 

 Mr. B. H. M. Bosanquet on the Measure of the Intensity of 



Sound 174 



Mr. N. D. C. Hodges on the Mean free Path of the Molecules 177 



Mr. L. Fletcher's Crystallographic Notes. (Plate V.) 180 



Mr. J. Bridge on a Calculating Apparatus, based on Napier's 



Bods. (Plate VI.) 191 



M. F. Lindemann on the Forms of the Vibrations of twitched 



and stroked Strings 197 



Mr. W. B. Birt on the Cyclones of the Bay of Bengal 221 



Mr. E. H. Hall on a new Action of the Magnet on Electric 



Currents 225 



