x Table of Contents 



CHAPTER VI 



PAGE 



TRANSPORTATION ON LAND .251 



Vehicles of Transportation, 253; Roads, 264; Railroads, 

 266 ; Curves, Inertia and its Effects, 274 : Bridges, 280 ; Steam 

 and the Locomotive, 289; The Production and Control of 

 Steam, 297; Electricity as a Motive Power, 316; Gasoline 

 as a Motive Power, 330. 



CHAPTER VII 



TRANSPORTATION ON WATER ...... . . 337 



Buoyancy, 338 ; Stability, 344 ; Rowing a Boat, 349 ; Sailing a 

 ' Boat, 353; The Steamship, 362; Instruments of Navigation, 

 370 ; Harbors, 379 ; Inland Waterways, 380. 



CHAPTER VIII 



TRANSPORTATION IN AIR . 389 



Balloons, 390 ; The Airplane, 394. 



CHAPTER IX 



BUILDING MATERIALS, THEIR USE AND ORIGIN .... 403 



Wood, 404 ; Stone, 406 ; Groups of Rocks, 413 ; Some Manu- 

 factured Mineral Products, 417. 



CHAPTER X 

 STEEL AND IRON . . . . . . . 429 



Properties of Iron, 431 ; Iron Ore, 432 ; Reduction of Iron 

 Ores, 437; Steel, 441 ; Wrought Iron, 449. 



CHAPTER XI 

 PLANTS IN RELATION TO MAN .... 454 



The Soil and Plants, 454 ; Natural and Artificial Selection, 

 477; Pollination and Seed Production, 483; Improvement of 

 Plants, 496 ; Propagation of Plants, 499 : Mendel's Law of In- 

 heritance, 505 ; Manufacture of Food by Plants, 515. 



