A single volume is of necessity too limited a space for anything approximating a complete record of the vast progress which has been made in American Industry. Consequently it has only been possible to select the more characteristic features of the twentieth century and point out the strides by which some of the prominent industries have advanced to their present proportions. If the hitherto undisputed maxim that “the more the individual knows the more he is worth to himself and his associates” still prevails, the chronicling of the developments in some fields should stimulate thought and experiment toward the adaptation of similar methods in others. It is to that end that authorities in each of the industries presented have co-operated in the compilation of this interesting and instructive volume. THE EDITOR. Table of Contents PAGE =THE STORY OF THE SUBMARINE= =9= Origin of Submarine Navigation, 9. The American Types, 10. Twentieth Century Submarines, 11. Engine Power, 12. The Periscope, 13. Voyage of the “Deutschland,” 14. Submarine Dredging, 15. =THE STORY OF THE PANAMA CANAL= =17= The United States to the Rescue, 17. The Canal and the Navy, 20. The Great Canal, 20. The Hydroelectric Station, 20. Gigantic Obstacles, 30. Gatun Dam, 33. Meeting all Emergencies, 33. A Battle Won, 36. =What is a Geyser? 40. What Kind of Dogs are Prairie-Dogs? 42. What is Spontaneous Combustion? 42.= =THE STORY IN THE TALKING MACHINE= =43= The Early Machines, 43. Invention of the Spring Motor, 47. Change from Cylinder to Disc, 47. Making the Record, 49. =What are Petrified Forests? 49. What Animals are the Best Architects? 51.= =THE STORY OF THE MOTORCYCLE= =52= Austin’s Steam Velocipede, 52. Motor-paced Racing, 55. First Practical Machine, 54. Modern Refinements, 57. Side Cars and Commercial Bodies, 58. =How is the Weather Man Able to Predict Tomorrow’s Weather? 58. How does a Siren Fog Horn Blow? 60.= =THE STORY IN A WATCH= =61= The Standard of Time, 61. Candles as Time-Keepers, 63. Galileo’s Pendulum, 63. Balance Wheel as a Pendulum, 65. The Time Train, 65. How a Watch Works, 67. What Causes Variation in Watches, 71. =How does a Monorail Gyroscope Railway Operate? 72. Why are Finger-prints used for Identification? 74.= =THE STORY IN A RIFLE= =75=