INDEX. 



521 



Costa (J.) on a peculiar case in the 

 refraction of organic compounds, 

 448. 



Crystallization, on some effects of 

 small quantities of foreign matter 

 on, 391. 



De Lapparent (Prof. A.) on the por- 

 phyritic rocks of Jersey, 66. 



De la Rive (L.) on Hertz's electrical 

 vibrations in air, 289, 516. 



Derby (O. A.) on Nepheline rocks in 

 Brazil, 142. 



Determinant of the sixth order, on a 

 peculiar, 429. 



Diabase, on the Variolitic, of the 

 Fichtelgebirge, 143. 



Dielectric constants, on the measure- 

 ment of, by means of Hertz oscil- 

 lations, 172. 



Dielectrics, on the changes of volumes 

 of, 146. 



Dobrzynski (F. v.) on the photo- 

 graphic action of electromagnetic 

 waves, 75. 



Dynamometry, contributions to, 346. 



Ebert (H.) on the motions of atoms 

 in the electrical discharge, 288. 



Elastic media, on the velocities of 

 propagation of disturbances in, 

 464. 



Electric arc between a ball and point, 

 on the alternating, 123. 



conductivity of hot gases, on 



the, 135, 415, 515. 



currents, on the heating of 



conductors by, 259. 

 field, on the illustration of the 



properties of the, by means of 



tubes of electrostatic induction, 



149. 

 Electrical convection, on, 74. 

 discharge, on the motions of 



atoms in the, 288. 

 force, on the reflexion of rays 



of, from plates of metal and of 



sulphur, 366. 

 - observations on the Hoher 



Sonnblick, on, 446. 



oscillations, on the quantitative 



photographic investigation of, 176. 



vibrations in air, on Hertz's, 



289, 290, 516. 



waves, on, 290. 



Electricity, on the conduction of, by 

 the vapours of heated salts, 290 ; 



Electrotytes, on the specific inductive 

 capacity of, 188. 



Electromagnetic radiation, on the 

 measurement of, 44. 



waves, on the photographic 



action of, 75. 



Electrometer as a wattmeter, on the, 

 504. 



Electromotive forces, on periodically 

 variable, in a conductor with self- 

 induction, 519. 



Elements of Mendelejeff's second 

 group, on the line-spectra of the, 

 368. 



Ellis (W.) on the diurnal variations 

 of magnetic elements, 36. 



Elster (Prof.) on electrical observa- 

 tions on the Hoher Sonnblick, 446. 



Emtage (W. T. A.) on the velocities 

 of propagation of disturbances in 

 elastic media, 464. 



Equilibrium, on the chemical, of 

 solids in its relation to pressure 

 and temperature, 9. 



Experiments, on the reduction of 

 results of, 418. 



Flexure of a flat elastic spring, 182. 



Fluorbenzene, on the refraction and 

 dispersion of, 1. 



Fluorine, on the optical properties 

 of, 7. 



Fluor-spar in optical instruments, on 

 the use of, 120. 



Focometry of diverging lens-combi- 

 nations, on the, 511. 



Gases, on the electric conductivity of 

 hot, 135, 415, 515 ; on the heat of 

 evaporation of liquefied, 291 ; on 

 the kinetic theory of, 441. 



Gauires, on the Bourdon, the Tait, 



and 

 400. 



the Amagat high-pressure, 



on Wheatstone's determination of 

 the velocity of, 519. 

 PMU Mag, S. 5. Vol. 31. No. 193. June 1891. 



Geitel (Prof.) on electrical observa- 

 tions on the Hoher Sonnblick, 446. 



Geological Society, proceedings of 

 the, 66, 142, 285, 439. 



Gladstone (Dr. J. H.) on the refrac- 

 tion and dispersion of fluorbenzene 

 and allied compounds, 1 ; on 

 secondary batteries, 42. 



Gladstone (G.) on the refraction and 

 dispersion of fluorbenzene and 

 allied compounds, 1. 



Gregory (J. W.) on the Variolitic 

 Diabase of the Fichtelgebirge, 143. 



Harker (A.) on the Snap granite, 

 288. 



2P 



