CONTENTS. xii 



CHAPTER XXXIV. 



SCIENCE OF THE NINETEENTH CENTURY (CONTINUED). 



PACK 



Early Theories about Heat — Count Rumford shows that Heat can 

 be produced by Friction — He makes Water boil by boring a 

 Cannon — Davy makes two pieces of Ice melt by Friction — His 

 conclusion about Heat— How * Latent Heat* is explained on 

 the theory that Heat is a kind of Motion — Dr. Mayer suggests 

 the Determination of the Mechanical Equivalent of Heat — Dr. 

 Joule's Experiments on the conversion of Motion into Heat — Dr. 

 Him's Experiments on the conversion of Heat into Motion — Proof 

 of the Indestructibility of Force and Conservation of Energy . 329 



CHAPTER XXXV. 



SCIENCE OF THE NINETEENTH CENTURY ^CONTINUED). 



Oersted discovers the Effect of Electricity upon a Magnet — Electro- 

 Magnetism — Experiments by Ampere on Magnetic and Electric 

 Currents — Ampere's Early Life — Direction of the North Pole of 

 the Magnet depends on the course of the Electric Currents — 

 Magnetic Currents set up between two Electric Wires— Electro- 

 Magnets made by means of an Electric Current — Arago magne- 

 tises a Steel Bar with an ordinary Electrical Machine — Faraday 

 discovers the Rotatory Movement of Magnets and Electrified 

 Wires — Produces an Electric Current by means of a Magnet — 

 Seebeck discovers Thermo-Electricity, or the production of Elec- 

 tricity by Heat — Schwabe discovers Periodicity of the Spots on 

 the Sun— Sabine suggests a connection between Sun-spots and 

 Magnetic Currents — This proved in 1859 by Observations of 

 Carrington and Hodgson — Electric Telegraph— Wheatstone — 

 Cooke — Steinheil — Morse — Bain ...... 34.1 



CHAPTER XXXVI. 



SCIENCE OF THE NINETEENTH CENTURY (CONTINUED). 



Davy discovers that Nitrous Oxide produces Insensibility — Laugh- 

 ing-gas — Safety-lamp, 181 5 — Nicholson and Carlisle discover 

 Decomposition of Water, 1800 — Davy discovers the effect of 

 Electricity upon Chemical Affinity — Faraday's Discoveries in 



