Discovery of Electrical Force--Diffused through all Matter--What is Electricity?--Theories--Frictional Electricity--Conducting Power of Bodies--Hypothesis of two Fluids--Electrical Images--Galvanic Electricity--Effects on Animals--Chemistry of Galvanic Battery--Electricity of a Drop of Water--Electro-chemical Action--Electrical Currents--Thermo-Electricity--Animal Electricity--Gymnotus--Torpedo--Atmospheric Electricity--Lightning Conductors--Earth’s Magnetism due to Electrical Currents--Influence on Vitality--Animal and Vegetable Development--Terrestrial Currents--Electricity of Mineral Veins--Electrotype--Influence of Heat, Light, and Actinism on Electrical Phenomena 193 CHAPTER X. MAGNETISM. Magnetic Iron--Knowledge of, by the Ancients--Artificial Magnets--Electro-Magnets--Electro-Magnetism--Magneto- Electricity--Theories of Magnetism--The Magnetic Power of soft Iron and Steel--Influence of Heat on Magnetism--Terrestrial Magnetism--Declination of the Compass-needle--Variation of the Earth’s Magnetism--Magnetic Poles--Hansteen’s Speculations--Monthly and Diurnal Variation--Dip and Intensity--Thermo-Magnetism--Aurora Borealis--Magnetic Storms--Magnetic conditions of Matter--Diamagnetism, &c. 235 CHAPTER XI. CHEMICAL FORCES. Nature’s Chemistry--Changes produced by Chemical Combination--Atomic Constitution of Bodies--Laws of Combination--Combining Equivalents--Elective Affinity--Chemical Decomposition--Compound Character of Chemical Phenomena--Catalysis or action of Presence--Transformation of Organic Bodies--Organic Chemistry--Constancy of Combining Proportions--The Law of Volumes, the Law of Substitutions, Isomeric States, &c. 270 CHAPTER XII. CHEMICAL PHENOMENA. Water--Its Constituents--Oxygen--Hydrogen--Peroxide of Hydrogen--Physical Property of Water--Ice--Sea Water--Chlorine--Muriatic Acid--Iodine--Bromine--Compounds of Hydrogen with Carbon--Combustion--Flame--Safety Lamp--Respiration--Animal Heat--The Atmosphere--Carbonic Acid--Influence of Plants on the Air--Chemical Phenomena of Vegetation--Compounds of Nitrogen--Mineral Kingdom, &c. &c. 295 CHAPTER XIII. TIME.--GEOLOGICAL PHENOMENA. Time, an element in Nature’s Operations--Geological Science--Its Facts and Inferences--Nebular Hypothesis applied--Primary Formations--Plutonic and Metamorphic Rocks--Transition Series--Palæozoic Rocks--Commencement of Organic Arrangements--Existence of Phosphoric Acid in Plutonic Rocks--Fossil Remains--Coal Formation--Sandstones--Tertiary Formations--Eocene, Miocene, and Pliocene Formations--Progressive changes now apparent--General Conclusions--Physics applied in explanation 332 CHAPTER XIV. PHENOMENA OF VEGETABLE LIFE.