CONTENTS OF VOLUME I. 



THE MINOR PLANETS PAGE 141 



Classification of the Planets. Mercury. Transit over the Sun. Relative Position with regard to 

 the Sun. Difficulty of observing it. Venus. Diurnal Motion of Venus and Mercury indicated 

 by the Shadows of Mountains. Direction of the Axis of Rotation. Seasons, Climates, and 

 Zones. Orbits and Transits of Mercury and Venus. Mountains on Mercury and Venus. Influ- 

 ence of the Sun at Mercury and Venus. Twilight on Mercury and Venus. Mars. Atmosphere 

 of Mars. Physical Constitution of Mars. Has Mars a Satellite ? Appearance of the Sun at 

 Mars. Its close Analogy to the Earth. 



WEATHER ALMANACS 157 



Merits of Weather Almanacs. Excitability of the London Public. Fright produced by Biela's 

 Comet. London Water Panic. London Air Panic. London Bread Panic. Rage for Weather 

 Almanacs. Patrick Murphy's Pretensions. Examination of the Predictions of the Weather 

 Almanac. Their Absurdity. Comparison of the Predictions with the Event. Morrison's 

 "Weather Almanac. Charlatanism of these Publications. Great Frost of 1838 in London. 

 Other Visitations of Cold. 



HALLEY'S COMET 169 



Predictions of Science. Structure of the Solar System. Motion of Comets. How to identify 

 them. Intervals of their Appearance. Halley's Comet. Its History. Newton's Conjectures. 

 Sagacity of Voltaire. Halley's Researches. Foretells the Reappearance of the Comet in 1759. 

 Principle of Gravitation applied to its Motion by Clairaut. Researches of that Mathematician. 

 Anecdotes of Lalande and Madame Lepaute. Minute and circumstantial Prediction of the Re- 

 appearance of Halley's Comet. Discovery of the Planet Herschel anticipated by Clairaut. 

 Reappearance of the Comet at the predicted Time. Second Prediction of its Return in 1835. 

 Prediction fulfilled. Observations on its Appearance in 1835. 



THE ATMOSPHERE 191 



Atmospheric Air is material. Its Color. Cause of the blue Sky. Cause of the green Sea. Air 

 has W eight. Experimental Proofs. Air has Inertia. Examples of its Resistance. It acquires 

 moving Force. Examples of its Impact. Air is impenetrable. Experimental Proofs. Elastic 

 and compressing Forces equal. Limited Height of the Atmosphere. Elasticity proportioned to 

 the Density. Experimental Proofs. Internal and external Pressure on close Vessels contain- 

 ing Air. 



THE NEW PLANETS 203 



Indications of a Gap in the Solar System. Bode's Analogy. Prediction founded upon it. Piazzi 

 discovers Ceres. Dr. Olbers discovers Pallas. Harding discovers Juno. Dr. Olbers discovers 

 Vesta. Indications afforded by these Bodies of the Truth of Bode's Predictions. Fragments 

 of a broken Planet. Others probably still undiscovered. Their ultra-zodiacal Motions. Their 

 Eccentricities. They are probably not globular. Other Singularities of their Appearance. 



THE TIDES 209 



Correspondence between the Tides and Phases of the Moon shown by Kepler. Erroneous popular 

 Notion of the Moon's Influence. Actual Manner in which the Moon operates. Influence of the 

 Sun. Combined Action of the Sun and Moon. Spring Tides. Counter-action of the Sun and 

 Moon. Neap Tides. Priming and Lagging of the Tides. Discussions at the British Association. 

 Whewell's Researches. Effect of Continents and Islands on the Tides. General Progress 

 of the Great Tidal Wave. Velocity of the Tidal Wave. Range of the Tide. 



LIGHT 22 1 



Structure of the Eye. Manner in which distant Objects become visible. Corpuscular Theory. 

 Undulatory Theory. Its general Reception. Velocity of Light. Account of its Discovery by 

 Roemer. Measurement of the Waves of Light by Newton. Color produced by Waves of 

 different Magnitudes. Magnitudes of Waves of different Color. Summary View of the Corpus- 

 cular Theory. Summary View of the undulatory Theory. These Theories compared. Discov- 

 eries of Dr. Young. Discoveries of Malus, Arago, Poisson, Herschel, and Airy. Relations of 

 Light and Heat. 



THE MAJOR PLANETS. 235 



Space between MARS and JUPITER. Jupiter's Distance and Period. His Magnitude and Weight. 

 His Velocity. Appearance of his Disk. Day and Night on Jupiter. Position of his Axis. 

 Absence of Seasons. His telescopic Appearance. His Belts. Causes of his B*elts. Currents 

 in his Atmosphere. Madler's telescopic Views of Jupiter. Appearance of the Sun as seen from 

 Jupiter. His Satellites. The Variety of his Months. Magnificent Appearance of the Moons as 

 seen from Jupiter. Their Eclipses. SATURN. His diurnal Rotation. Appearance of the Sun 

 as seen from him. His Atmosphere. His Rings. Their Dimensions. Biot's Explanation of 

 their Stability. Herschel's Theory of the same. Appearances and Disappearances of the 

 Rings. Various Phases of the Rings. Saturn's Satellites. HERSCHEL or URANUS. His Dis- 

 tance and Magnitude. His Moons. Reasons why there is no Planet beyond his Orbit. 



REFLECTION OF LIGHT 257 



Ray of Light. Pencil of Light Reflection. Irregular Reflection. Regular Reflection. Different 

 Powers of Reflection in different Bodies. Reflection at plane Surfaces. Its Laws. Image of 

 an Object in a plane Reflector. Reflection of curved Surfaces. Concave Reflectors. Convex 

 Reflectors. Images in spherical Reflectors. Illusion of the Air-drawn Dagger. Effects of com- 



