TABLE OF CONTENTS. iii 



on the Temperature of the Solar Spots, 12 ; Solar Spots and Terrestrial 

 Phenomena, 13 ; on the Relative Temperature of Various Portions of the 

 Sun, 13 ; the Absorption of the Solar Atmosphere, 15 ; the Solar Atmos- 

 phere and Radiated Heat, 40 ; tlie Coronal-line 1-474 I; 44 ; the Solar Paral- 

 lax, 51 ; Solar Spots, 53 ; the Solar Spots and Protuberances of the Sun from 

 1871 to 1875, 55; Spectroscopic Diameter of the Sun, 57; Photographs 

 of the Solar Corona, 60 ; Connection between Solar Spots and Terrestrial 

 Electricity, 122. The Planets : Dimensions of the Satellites of Jupiter, 

 21 ; on Physical Observations of the Planet Jupiter, 26 ; on the Brightness 

 of the Satellites of Jupiter, 27 ; Theory of the Satellites of Jupiter, 32 ; the 

 Satellites of Saturn, 21 ; the Atmosphere of Yenus, 27 ; the Uranian and 

 Neptunian Systems, 34 ; Supposed Observation of an Inter-mercurial Plan- 

 et, 46; the Inner Satellites of Uranus, 52; Theory of Planetary Perturba- 

 tions, 25 ; Diameters of the Inferior Planets as Affected by Diffraction, 29 ; 

 Movement of a Planet in a Resisting Medium, 33. The Moon : The Lunar 

 Theory, 38 ; Lunar iMaps, 45 ; Relation of the Phases of the Moon to At- 

 mospheric Pressure, 133 Meteoroids or Shooting-stars : On Observations 

 of Shooting-stars from Balloons, 14; Observations on the Shooting-stars 

 of the 10th of August, 1875, 14 ; Meteors of August 10th and 11th, 1875, 28 ; 

 Spectra of the Gases Contained in Meteorites, 28. Comets ; The Comet 

 III., 1862, 35 ; Orbit of Comet II., 1840, 36 ; on the Calculation of the Ab- 

 solute Perturbations of Comets, 36 ; Spectrum of Coggia's Comet, 37 ; the 

 Periodic Comet of D'Arrest, 37 ; Identity of Comet YIL, 1873 (Coggia), with 

 Comet L, 1818 (Pons), 57. The Aurora and Zodiacal Light : Observa- 

 tions on the Zodiacal Light, 35 ; Magnetism and the Aurora, 75 ; Periodic- 

 ity of the Aurora, 96 ; on the Height of the Aurora Borealis, 132, Miscel- 

 laneous : On Terrestrial Refraction, 6 ; Celestial Photometry, 7 ; on the 

 Theory of the Aberration of Light, 8; Correlation of Solar and Terrestrial 

 Phenomena, 8 ; Prizes Proposed for Astronomical Works in 1876, 52 ; the 

 Lalande Prize, 52 ; Alsibility of Stars in the Daytime, 64. Observatories 

 and Instruments, and their Uses, Time, etc. : Dijllen's jNlethod of De- 

 termining Local Time, 5 ; Accuracy of Chronometers, 6 ; Distribution of 

 Standard Time in Switzerland, 41 ; Egyptian Chronology, 42 ; Distribution 

 of Public Time throughout the World, 60 ; IMeasure of Time by Hour- 

 glasses, 64 ; Astronomical Observations at Mannheim, 38 ; Astronomical 

 Observations at Milan, 38 ; the Spectroscopic Observatory at Calcutta, 40 ; 

 Glass Divided Circles for the Measurement of Angles, 46 ; List of Latitude 

 Stars employed in the Coast Survey, 47 ; Publications of the Observatory 

 of Bothkamp, 51 ; the Solar Observatory at Potsdam, 56 ; a New Meridian 

 Instrument at the Observatory at Rio, 57 ; the great Paris Telescope, 39 ; 

 large Telescopes, 40. 



B. TERRESTRIAL PHYSICS AND METEOROLOGY (xxvii) 65 



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



The Land : Origin of Yolcanic Ashes, 66 ; Formation of Basalt Columns, 

 70; Earthquakes in Italy, 72; Abnormal Deflections of the Plumb-line, 

 67; Underground Temperatures, 69; the Internal Heat of the Earth, 74; 

 on the Power of Leaves to Absorb and Radiate Heat, 76; on the Tempera- 

 ture of the Soil, 77 ; the Temperature of the Earth, 98 ; the Internal Tern- 



