; v TABLE OF CONTENTS. 



of Computing Planetary Perturbations, 43 ; Mercury: Reflecting Power 

 of the Planet Mercury, 18; Venus: the Atmosphere of Venus, 19; the 

 Visibility of the Planet Venus, 19; Results of the American and other Ob- 

 servations of the Transit of Venus, 52 ; Jupiter : the Mass of Jupiter, 20 ; 

 J-Airth : the Tidal Retardation of the Earth's Motion, 20; the Variability 

 of Terrestrial Latitudes, 31 ; Simple Method of Determining Latitude, 31 ; 

 Determination of Latitude and Time, 32; Uranus: the Satellites of 

 Uranus, 20. Meteoroids : Origin of Aerolites, 21 ; Galle's Path of the 

 Meteor of June 17, 1873, 44 ; Two Groups of November Meteorites, 45 ; 

 on the Structure of Comets and Meteors, 47 ; Meteorites in India, 61. 

 Comets: the Great Comet of 1684, 21; the Phenomena of Comets, 22; 

 the Constitution of Comets, 23 ; the Formation of the Tails of Comets, 23 ; 

 Winnecke's Comet, 24 ; on the Repulsive Forces of Comets, 25 ; Encke's 

 Comet, 45; on the Structure of Comets and Meteors, 47; on Cometary 

 Orbits, 47 ; the Distribution of Cometary Orbits, 48 ; Bruhns on Pogson's 

 and Biela's Comets, 49. Auroras : Peculiar Auroral Phenomena, 26 ; the 

 Spectrum of the Aurora Borealis, 26; the Geographical Distribution of 

 Auroras, 26 ; Ground Currents and the Aurora, 27 ; on the Electric Dis- 

 charges in the Aurora Borealis, 50. Observatories and Instruments, and 

 their Uses, Time, etc. : The Celestial Indicator, 28 ; on the Errors of 

 Micrometric Measurements, 29 ; Astronomical Work with the Great Mel- 

 bourne Telescope, 29 ; the German Nautical Observatory, 30 ; the Fixed 

 Horizontal Telescope of Laussedat, 30 ; Astronomical Work at Cordoba, 34 ; 

 Lord Rosse's Three-foot Telescope, 50 ; Compensation of Clocks for the In- 

 fluence of Barometric Changes, 51 ; Time Arrangement at Pittsburgh, 3, 

 60 ; Ancient Egyptian Astronomical Observations, 61. 



B. TERRESTRIAL PHYSICS AND METEOROLOGY. . . . (xxxiii, xxxv) 63 

 (a.) TERRESTRIAL PHYSICS (including Dynamical Geology). 



The Land in general : On the Evaporation of Water from Hard and 

 Broken Soils, 63 ; on the Conductivity of Various Kinds of Soil for Heat, 

 63 ; the Penetration of Cold into the Earth, 86 ; the Figure of the Earth, 

 67 ; Underground Temperatures, 68 ; Ice-cave near Dobschau, 68 ; Influence 

 of Forests on Climate, 74 ; Dryness of the Soil in India, 94. Earthquakes : 

 Earthquakes and Magnetic Disturbances, 64 : the Earthquake of Belluno, 

 65 ; the Earthquake of the 22d of October, 1873, 66 ; Earthquake in the 

 Vicinity of New York, December 10, 1874, 93. Volcanoes : Recent Vol- 

 canic Phenomena in Iceland, 67 ; Volcanoes in Iceland and Ash-showers in 

 Norway, 93 ; a New Seismometer, 90. Glaciers : Glaciers of the Hima- 

 layas, 113. Terrestrial Magnetism: Earthquakes and Magnetic Dis- 

 turbances, 64; Magnetic Disturbances and Auroras in the Arctic Regions, 

 95; the Magnetic Declination at St. Petersburg, 96; Earth-currents on 

 Telegraphic Lines, 159, 1G3 ; Measurements of Terrestrial Magnetism, 164: 

 New Method of Investigating Terrestrial Magnetism, 165. The Interior 

 Waters : Physical and Faunal Resemblances between the Lakes of Galilee 

 and of Utah, 64 ; the Deposition of Fine Sediments, 69 ; so-called Tides 

 in Great Lakes, 69 ; Changes in the Level of the Waters of Lake Geneva, 

 99 ; the Electrical Condition of Spring Water, 101 ; on the Secular Diminu- 

 tion in Europe of Springs, Rivers," and Streams with the Simultaneous 



