Early Use of Caoutchouc by the Indians. Collection of the Gum. Early Experiments Failures. Goodyear’s Persistent Experiments. Nathaniel Hayward’s Application of Sulphur to the Gum. Goodyear’s Process of Vulcanization. Introduction of his Process into Europe. Trials and Imprisonment for Debt. Rubber Shoe Industry. Great Extent and Variety of Applications. Statistics. CHAPTER XVIII. CHEMISTRY. Its Evolution as a Science. The Coal Tar Products. Fermenting and Brewing. Glucose, Gun Cotton, and Nitro-Glycerine. Electro-Chemistry. Fertilizers and Commercial Products. New Elements of the Nineteenth Century. CHAPTER XIX. FOOD AND DRINK. The Nature of Food. The Roller Mill. The Middlings Purifier. Culinary Utensils. Bread Machinery. Dairy Appliances. Centrifugal Milk Skimmer. The Canning Industry. Sterilization. Butchering and Dressing Meats. Oleomargarine. Manufacture of Sugar. The Vacuum Pan. Centrifugal Filter. Modern Dietetics and Patented Foods. CHAPTER XX. MEDICINE, SURGERY AND SANITATION. Discovery of Circulation of the Blood by Harvey. Vaccination by Jenner. Use of Anæsthetics the Great Step of Medical Progress of the Century. Materia Medica. Instruments. Schools of Medicine. Dentistry. Artificial Limbs. Digestion. Bacteriology, and Disease Germs. Antiseptic Surgery. House Sanitation. CHAPTER XXI. THE BICYCLE AND AUTOMOBILE. The Draisine, 1816. Michaux’s Bicycle, 1855. United States Patent to Lallement and Carrol, 1866. Transition from “Vertical Fork” and “Star” to Modern “Safety.” Pneumatic Tire. Automobile the Prototype of the Locomotive. Trevithick’s Steam Road Carriage, 1801. The Locomobile of To-day. Gas Engine Automobiles of Pinkus, 1839; Selden, 1879; Duryea, Winton, and Others. Electric Automobiles a Development of Electric Locomotives as Early as 1836. Grounelle’s Electric Automobile of 1852. The Columbia, Woods, and Riker Electric Carriages. Statistics. CHAPTER XXII. THE PHONOGRAPH. Invention of Phonograph by Edison. Scott’s Phonautograph. Improvements of Bell and Tainter. The Graphophone. Library of Wax Cylinders. Berliner’s Gramophone. CHAPTER XXIII. OPTICS. Early Telescopes. The Lick Telescope. The Grande Lunette. The Stereo- Binocular Field Glass. The Microscope. The Spectroscope. Polarization of Light. Kaleidoscope. Stereoscope. Range Finder. Kinetoscope, and Moving Pictures. CHAPTER XXIV. PHOTOGRAPHY. Experiments of Wedgewood and Davy. Niépce’s Heliography. Daguerre and the Daguerreotype. Fox Talbot Makes First Proofs from Negatives. Sir John Herschel Introduces Glass Plates. The Collodion Process. Silver and Carbon Prints. Ambrotypes. Emulsions. Dry Plates. The Kodak Camera. The Platinotype. Photography in Colors. Panorama Cameras. Photo-engraving and Photo-lithography. Half Tone Printing. CHAPTER XXV. THE ROENTGEN OR X-RAYS.