CONTENTS OF VOLUME I. 



mon Looking-Glasses analyzed. A flattering Glass explained. Metallic Specula. Reflection in 

 Liquids. Image of the Banks of a Lake or River. 



PROSPECTS OF STEAM-NAVIGATION PAGE 267 



Paddle- Wheels. Defects of the present Steam- Vessels as applicable to "War. Difficulty of long 

 Ocean-Voyages. Ericsson's Propeller. Loper's Propeller. Advantages of Submerged Propel- 

 ler. Method of raising the Propeller out of the Water. Fuel. Form and Arrangement of the 

 proposed Steam Packet-Ships. War-Steamers. The Princeton. Effects to ensue from the new 

 Steamships. Conclusion. 



THE BAROMETER 277 



Maxim of the Ancients. Abhorrence of a Vacuum. Suction. Galileo's Investigations. Torricelli 

 discovers the Atmospheric Pressure. The Barometer. Pascal's Experiment. Requisites for a 

 good Barometer. Means of securing them. Diagonal Barometer. Wheel Barometer. Ver- 

 nier. Uses of the Barometer. Variation of Atmospheric Pressure. Weather- Glasses. Rules in 

 common Use absurd. Correct Rules. Measurement of Heights. Pressure on Bodies. Why 

 not apparent. Effect of a Leather Sucker. How Flies adhere to Ceilings and Fishes to Rocks. 

 Breathing. Common Bellows. Forge Bellows. Vent Peg. Teapot. Kettle. Ink-Bottles. 

 Pneumatic Trough. Gurgling Noise in decanting Wine. 



THE MOON 299 



Popular Interest attached to the Moon. Its Distance. Its Rotation. Same Face always toward 

 the Earth. Its Phases. Its changes of Position with regard to the San. Has it an Atmosphere ? 

 Optical Test to determine it. Physical Qualities of Moonlight. Is Moonlight "warm or 

 cold? Does Water exist on the Moon? Does the Moon influence the Weather? Mode of 

 determining this. Physical Condition of the lunar Surface. Absence of Air and Gases. Ab- 

 sence of Liquids. Appearance of the Earth as seen from the Moon. Prevalence of Mountains 

 upon it. Their general volcanic Character. Appearance of the Mountain Tycho. Heights of 

 lunar Mountains and Depths of Ravines. Telescopic Views of the Moon by Beer and Ma'dler. 

 Detached Views of the lunar Surface. Condition of a lunar Crater deduced from Analogy. 



HEAT 317 



Heat as a Branch of elementary Physics neglected. Has as strong Claims as Light, Electricity, or 

 Magnetism. Is a universal Agent in Nature. In Art. In Science. Astronomy. Chemistry. 

 In every Situation of Life. Applications of it in Clothing and artificial Warming and Cooling. 

 Lighting. Admits of easy explanation. Dilatation. Examples. Thermometer. Melting and 

 boiling Points. Evaporation. Specific Heat. Heat produced by Compression. Radiation. 

 Conduction. Incandescence. 



GALVANISM 327 



Origin of the Discovery. Galvani Professor at Bologna. Accidental Effect on Frogs. Ignorance 

 of Galvani. His Experiments on the Frog. Accidental Discovery of the Effect of metallic 

 Contact. Animal Electricity. Galvani opposed by Volta. Volta's Theory of Contact prevails. 

 Fabroni's Experiments. Invention of the Voltaic Pile. La Couronne des Tasses. Napoleon's 

 Invitation to Volta. Physiological Effects of the Pile. Anecdote of Napoleon. Decomposition 

 of Water. Cruickshank's Experiments. Davy commences his Researches. Effect of Chemical 

 Action discovered. Ritter's Secondary* Pile. Calorific Effects of the Pile. Hypothesis of 

 GrotthuSrf Davy's celebrated Bakerian Lecture. Prize awarded him by the French Academy. 

 His Discovery of the Transferring Power of the Pile in chemical Action. His Electro-Chemical 



Theory. Decomposition of Potash and Soda. New Metals, Potassium and Sodium. Discovery 

 of Barium. Strontium, Calcium, and Magnesium. Rapid Discovery of the other new Metals. 

 Dry Piles. 



THE MOON AND THE WEATHER 371 



Ancient Prognostics of Aristotle, Theophrastus, Aratus, Theon, Pliny, Virgil. Recent Predictions. 

 Theory of Lunar Attraction not in accordance with popular Opinion. Changes of Weather com- 

 pared with Changes of the Moon. Prevalence of Rain compared with lunar Phases. Direction 

 of the Wind. Height of Barometer compared with lunar Phases. Erroneous Notions of Cycles 

 of nineteen and nine Years. Cycle of four and eight Years mentioned by Pliny. 



PERIODIC COMETS 389 



Encke's Comet. Its Period and Orbit. How its Motion shows the Existence of a resisting 

 Medium. This Result corroborated by the Theory of Light Newton's Conjectures respecting 



