=Where are Milk-Pails Filled from Trees? 383. How did the Wearing of a Crown Originate? 384. Why do Lobsters change Color? 384. How do Fishes Swim? 384. Where do Pearls Come from? 385. What is Cork? 385.= =THE STORY IN A GIANT CANNON= =386= Origin of the Cannon, 386. Modern Cannon, 392. How Cannon are Now Made, 393. Built-Up and Wire-Wound Guns, 394. Feats of Modern Guns, 406. =What is a Deep-Sea Diver’s Dress Like? 411. Why do We Smile when We are Pleased? 412. Why do Some of Us have Freckles? 412.= =PICTORIAL STORY OF THE STEEL INDUSTRY= =413= Mining Ore, 413. Open-Hearth Furnaces, 416. Blast Furnaces, 417. A 15,000 Ton Forge, 418. Oil-Tempering, 420. Bending Armor Plate, 422. Largest Steel Casting in the World, 424. Casting Steel, 431. Rolling Rails, 432. =What do We Mean by “Deviation of the Compass?” 435.= =THE STORY IN THE MAKING OF A PAIR OF SHOES= =436= Shoemaking by Machine, 436. Cross-Section of a Shoe, 437. Lasting Machine, 440. Details of the Process, 442. Evolution of a Shoe, 447. =What is Standard Gold? 448. What are Cyclones? 450. What Metals can be Drawn into Wire Best? 450. How are Cocoanuts Used to Help our Warships? 450. How did the Dollar Sign Originate? 450.= =PICTORIAL STORY OF FIRE APPARATUS= =451= Aerial Truck, 451. Motor Fire Engine, 451. Old-time Apparatus, 452. Chemical Engine, 455. =STORY OF THE TAKING OF FOOD FROM THE AIR= =458= Nitrogen and Oxygen in the Air, 458. Fixation of Nitrogen, 459. Liquid Air, 460. Fertilizer, 461. Ammonia, 466. =What is a Drawbridge Like Today? 466.= =THE STORY OF A DEEP-SEA MONSTER= =468= A Thirty-nine Hour Battle, 468. Five Harpoons and 151 Bullets needed, 468. An Unknown Leviathan, 470. =What is an Armored Railway Car Like? 470. What is an Electric Eel? 472.= =THE STORY OF SALT= =473= Natural Salt, 473. The Polish Mines, 474. Refining, 476. =Why do We Call it “Denatured Alcohol”? 478. What is the Difference between a Cruiser and a Battleship? 478.= =THE STORY OF THE GROWTH OF THE MOTOR TRUCK= =481= Practically Developed since 1905, 481. Cheaper Transportation, 489. =What is a Diving Bell? 489. How are Harbors Dredged Out? 491. How is a Razor Blade Made? 491.= =THE STORY OF THE TUNNELS UNDER THE HUDSON RIVER= =492= Bold Engineering, 492. 40,000 Men, 492. How the Tunneling Shield Works, 494. Air Pressure, 496. Extraordinary Adventures under the River, 501. =What Causes Floating Islands? 504.= =PICTORIAL STORY OF THE AIRSHIP= =505=