text: Lecture 1: A Candle: The Flame - Its Sources - Structure - Mobility - Brightness
  Lecture 2: Brightness of the Flame - Air necessary for Combustion - Production of Water
  Lecture 3: Products: Water from the Combustion - Nature of Water - A Compound - Hydrogen
  Lecture 4: Hydrogen in the Candle - Burns into Water - The Other Part of Water - Oxygen
  Lecture 5: Oxygen present in the Air - Nature of the Atmosphere - Its Properties - Other Products from the Candle - Carbonic Acid - Its Properties
  Lecture 6: Carbon or Charcoal - Coal Gas Respiration and its Analogy to the Burning of a Candle - Conclusion