xviii CONTENTS. 



nation of the facts — Abraham Werner lectures on Mineralogy 

 and Geology, 1775 — Disputes between the Neptunists and Vul- 

 canists— Dr. Hutton first teaches that it is by the Study of the 

 Present that we can understand the Past — ^Theory of Hutton — 

 Sir J. Hall's Experiments upon Melted Rocks — Hutton dis- 

 covers Granite Veins in Glen Tilt — William Smith, the * Father 

 of English Geologists ' — His Geological Map of England . . 214 



CHAPTER XXVII. 



SCIENCE OF THE EIGHTEENTH CENTURY (CONTINUED). 



Birth of Modem Chemistry — Discovery of * Fixed Air,' or Car- 

 bonic Acid, by Black and Bergmann — Working out of * Che- 

 mical Affinity ' by Bergmann — He tests Mineral Waters, and 

 proves ' Fixed Air ' to be an Acid — Discovery of Hydrogen by 

 Cavendish — He investigates the Composition of Water — Oxygen 

 discovered by Priestley and Scheele — Priestley's Experiments — 

 He fails to see the true bearing of his Discovery — His Political 

 Troubles and Death — Nitrogen described by Dr. Rutherford — 

 Lavoisier lays the Foundation of Modern Chemistry — He 

 destroys the Theory of * Phlogiston ' by proving that Combustion 

 and Respiration take up a Gas out of the Air — Discovers the 

 Composition of Carbonic Acid and the nature of the Diamond — 

 French School of Chemistry — Death of Lavoisier , . . 225 



CHAPTER XXVIII. 



SCIENCE OF THE EIGHTEENTH CENTURY (CONTINUED). 



Doctrine of Latent Heat, taught by Dr. Black in 1760 — Water 

 containing Ice remains always at 0° C, and Boiling Water at 

 100° C, however much Heat is added — Black showed that the 

 lost Heat is absorbed in altering the condition of the Water — 

 Watt's Application of the Theory of Latent Heat to the Sleam- 

 engine^Early History of Steam-engines — Newcomen's Engine 

 — Watt invents the Separate Condenser — Diagram of Watt's 

 Engine— Difficulties of Watt and Boulton in introducing Steam- 

 engines 241 



