Origin of Coal, 9. Coal of various ages, 11. Graphite, 12. Recent Vegetable Deposits, 13. Mode of occurrence of Coal, 13. Structure of Coal, 15. Uses of Coal, 16. Coal a source of Energy, 17. Mechanical Equivalent of Heat, 19. Value of Coal as a Fuel, 20. Small efficiency of Steam-engines, 21. Mechanical value of Coal, 22. Whence Coal derives its Energy, 22. Chemical Composition of Coal, 23. Growth of Plants, 26. Solar Energy, 28. Transformation of Wood into Coal, 30. Destructive Distillation of Coal, 33. Experiments of Becher, 34; of Dean Clayton, 35; of Stephen Hales, 37; of Bishop Watson, 37; of the Earl of Dundonald, 39. Coal-gas introduced by Murdoch, 40. Spread of the new Illuminant, 41. Manufacture of Coal-gas, 42. Quantitative results, 45. Uses of Coke, 47. Goethe's visit to Stauf, 48. Bishop Watson on waste from Coke-ovens, 50. Shale-oil Industry, 50. History of Coal-mining, 57. Introduction of Coal into London, 58. The Coal resources of the United Kingdom, 60. Competition between Electricity and Coal-gas, 62. CHAPTER II. Ammoniacal Liquor of Gas-works, 64. Origin of the Ammonia, 65. Ammonia as a Fertilizer, 65. Other uses of Ammonia, 67. Annual production of Ammonia, 68. Utilization of Coal-tar, 69. The Creosoting of Timber, 70. Early uses of the Light Tar Oils, 71. Discovery of Benzene by Faraday; isolation from Tar Oil by Hofmann and Mansfield, 73. Discovery of Mauve by Perkin, 74. History of Aniline, 75. The Distillation of Coal-tar, 77. Separation of the Hydrocarbons of the Benzene Series, 82. Manufacture of Aniline and Toluidine, 87. History and Manufacture of Magenta, 89. Blue, Violet, and Green Dyes from Magenta, 92. The Triphenylmethane Group, 97. The Azines, 108. Lauth's Violet and Methylene Blue, 111. Aniline Black, 114. Introduction of Azo-dyes, 115. Aniline Yellow, Manchester Brown, and Chrysoidine, 118. The Indulines, 121. Chronological Summary, 122. CHAPTER III.