552 



INDEX. 



Kicketts (Dr. C.) on some erratics in 

 the Boulder-clay of Cheshire, 207. 



Koberts (T.) on the lower Palaeozoic 

 rocks of Haverfordwest, 208. 



Rotations, optical comparisons of 

 methods for observing small, 360. 



Salt-solutions, on supersaturation of, 

 295. 



Sarasin (E.) on the depth to which 

 daylight penetrates in sea-water, 

 74. 



Selenium, on the sensitiveness of, to 

 light, 178. 



Semmola (E.) on the tones produced 

 in a plate by frequent discharges of 

 an electrical machine, 548. 



Sire (G.) on two new types of con- 

 densing hygrometers, 468. 



Smith (0. M.) on atmospheric elec- 

 tricity, 456. 



Stream -lines of moving vortex-rings, 

 on the, 67. 



Strenger (F.) on the electric conduc- 

 tivity of gases, 305. 



Sulphur, on the sensitiveness of, to 

 light, 178; on the generation of 

 electric currents by, 328. 



Surface-tensions, on Quincke's me- 

 thod of calculating, 51. 



Sutherland (W.) on the mechanical 

 integration of the product of two 

 functions, 175. 



Thermodynamical relations, on some, 

 515. 



Thermometer, on the determination 

 of the heat- capacity of a, 48 ; on a 

 differential resistance-, 384. 



Thermopile, on the thermodynamic 

 efficiency of the, 361. 



Thunder-clouds, on the electrical 

 processes in, 34. 



Tomlinson (0.) on the bleaching of 

 iodide of starch by heat, 168. 



Vacuum, on the velocity with which 

 air rushes into a, 531. 



Voltaic cell, on the seat of the elec- 

 tromotive forces in a, 336, 372. 



Vortex-rings, on the stream-lines of 

 moving, 67. 



Water-jets, on colliding, 31. 



Watts (W. W.) on the igneous rocks 

 of the Breidden Hills, 211. 



Webster (A. G.) on the mechanical 

 equivalent of heat, 217. 



Wiedemann (Prof. E.) on the disen- 

 gagement of heat in the swelling 

 and solution of colloids, 220. 



Wilde (H.) on the velocity with 

 which air rushes into a vacuum, 531. 



Williams (G.) on the source of the 

 hydrogen occluded by zinc dust, 

 464. 



Wood (De Volson) on the luminife- 

 rous aether, 389. 



Worthington (A. M.) on the error 

 involved in Quincke's method of 

 calculating surface-tensions, 5.1. 



Wroblewski (S.) on the separation of 

 liquid atmospheric air into two 

 different liquids, 463. 



Young (Dr. S.) on some thermody- 

 namical relations, 515. 



Zinc dust, on the occlusion of, by hy- 

 drogen, 464. 



END OF THE TWENTIETH VOLUME. 



Printed by Taylor and Francis, Red Lion Court, Fleet Street. 



