Part 147

=Tunnels=, accidents in, 218 causes of accidents, 218 accuracy of engineering, 215 airlocks, description of, 213 operation of airlocks, 213 compressed air method, 211 the bends, 213 bends, the danger of, 213 bends, the symptoms of, 213 dangers in building, 218 grommetting the bolts, (illus.), 214 borings in ground (illus.), 216 airlock bulkhead (illus.), 210 how built, 209 driving shield rear end of in tunnel building (illus.), 210 caissons in Hudson tunnels (illus.), 217 curves, how made (illus.), 216 how shield cuts through, 212 how dug under water, 208 erector (illus.), 210 erector at work (illus.), 214 grouting (illus.), 214 inventor of shield method, 209 inventor of compressed air method, 211 caulking the joints (illus.), 214 making joints water tight, 214 at end of journey (illus.), 216 land end of Hudson tunnels (illus.), 217 danger of leaks, 213 result of leaks (illus.), 213 concrete lining (illus.), 216 key plate (illus.), 214 diagrams of driving shield (illus.), 208 biggest ever built by shield method, 209 rear end of driving shield (illus.), 210 driving shield front view (illus.), 209 how the shields meet exactly (illus.), 215 models of Penna RR. tunnel shield (illus.), 212

=Turbine=, how it works (illus.), 344

=Twinkle=, what makes stars, 38

=Twinkling stars=, due to interference, 38

=Types= of cartridges (illus.), 49

=Umbrella=, who made the first, 312 who carried the first, 312

=Uncle Sam=, how name originated, 458

=Undercutting= with compressed air machine (illus.), 261

=Vault= of telephone cables (illus.), 67

=Velocity= of a projectile, 53

=Waking=, why we wake up, 365

=Walking=, difficult to, straight with eyes closed, 91 why cannot babies walk as soon as born, 180

=Wall=, sounds through a thick, 79

=Water=, aqueduct (illus.), 505 Ashokan Reservoir (illus.), 502 boiling-point of, 35-220 drinking, where does it come from, 501 hard, 221 how is a big dam built, 502 Hudson River siphon (illus.), 507 in ocean where it came from, 218 pumping station (illus.), 503 real source of the (illus.), 506 regulating chamber (illus.), 506 reservoir, 503 soft, 221 as standard in measuring specific gravity solids, 268 what made of, 348 what makes it boil, 220 what makes water shoot in air, 198 what hard is, 221 what soft is, 221 why don’t water in ocean sink in, 219 why does it run, 219 why it puts fire out, 222 why runs off a duck’s back, 233 why sea water is salty, 351

=Watson, Thomas A.=, (illus.), 70

=Wave=, of light changed into heat, 36

=Waves=, of sound, 79

=Weight=, of light, 37 of projectiles, 53

=What= does the air weigh? 398 animal can leap the greatest distance? 122 causes an arrow to fly? 408 makes some people bald? 143 keeps a balloon up? 199 makes a ball stop bouncing, 63 are ball bearings? 180 happens when a bee stings? 537 makes the hills look blue sometimes? 255 makes me blush? 194 was the origin and meaning of bread? 460 is the hottest spot on earth? 239 holds a building up? 496 makes a bubble explode, 108 is carbonic acid? 509 is a cable made of? 429 is the eye of the camera? 22 do ocean cables look like when cut in two? (illus.), 428 do we mean by 18-carat fine? 266 is clay? 495 is color? 123 produces the colors we see? 123 makes the colors in the rainbow? 254 makes the colors of the sunset? 253 are cocoa shells? 390 is cement? 95 is cement used for? 95 a cement mill looks like (illus.), 96 is cement made of? 95 is cement used for, 95 is concrete? 95 makes some things in the same room colder than others? 144 does woolen cloth come from? 80 was the cross-bow? 44 are diamonds made of? 351 causes dimples? 352 makes us dream? 366 were man’s first divisions of time? 314 makes things whirl around when I am dizzy? 402 is dust? 104 becomes of the dust? 104 are drone bees good for? 531 is meant by deadening a floor or a wall? 79 causes earache? 410 makes an echo? 200 are the principal parts of an elevator? 396 causes the explosion in a gas engine? (illus.), 182 happens when anything explodes? 205 is an element? 349 makes the hollow place in a boiled egg? 179 is electricity? 329 is an electric current? 334 makes an electric magnet lift things? 326 do we mean by Fahrenheit? 221 makes a fish move in swimming? 233 is fog? 105 makes the water from a fountain shoot into the air? 198 makes freckles come? 125 makes a gasoline engine go? 181 is gravitation? 267 does specific gravity mean? 268 makes a cold glass crack if we put hot water in it? 63 are ghosts? 367 causes the gurgle when I pour water from a bottle? 63 causes hail? 124 is the horizon? 244 causes a hot box? 368 good are the lines on the palms of our hands? 402 does horse-power mean? 256 is hydrogen gas? 349 makes us feel hungry? 243 makes knots in boards? 223 were the earliest lamps? 295 were the lamps of the wise and foolish maidens? 295 happens when we laugh? 93 makes us laugh when glad? 92 is a leyden jar? 332 is a lodestone? 327 makes lobsters turn red? 245 makes the lump come in my throat when I cry? 195 makes a match light when we strike it? 198 would we do without matches? 292 is a metal? 265 is the most valuable metal? 265 is the milky way? 255 is a molecule? 348 is money? 455 is motion? 61 made the mountains? 401 is music? 478 does a note in music consist of? 490 is organic matter? 174 is oxygen? 349 is nitrogen? 350 makes nitroglycerin explode so readily? 206 causes nightmare? 367 is pain and why does it hurt? 244 makes the different colors in paint? 229 is pitch in music? 489 is the principle of the wireless? 455 makes some pencils hard and others soft? 467 makes rays of light? 230 makes us red in the face? 192 makes the rings in the water when I throw a stone into it? 197 is rubber? 386 is wild rubber? 387 should I do if stung by a bee? 537 is the cause of shadows? 495 makes the sea roar? 401 does the bottom of the sea look like? 220 becomes of the smoke? 106 and why is smoke? 105 causes the smoke when a gun goes off? 206 is smokeless powder made of? 206 makes snowflakes white? 409 depth of snow is equivalent to an inch of rain? 241 is soap made of? 411 makes a soap bubble? 108 shot tower looks like? 51 makes us sneeze? 194 is silver? 207 happens when we stretch? 193 makes me want to stretch? 192 happens when I swallow? 195 is sound? 485 are the properties of sound? 486 are the sounds we hear in a sea shell? 79 makes the sounds like waves in a sea shell? 79 does a sounding board do? 488 is meant by the length of sound waves? 487 makes us thirsty? 243 makes me tired? 403 a great steamship looks like inside (illus.), 346 did the first telephone look like? (illus.), 72 occurs when we think? 194 are the big tanks near the gas works for? 298 makes the stars twinkle? 38 a ship’s turbine looks like (illus.), 344 is the largest tree in the world? 242 happens when we telephone? 65 makes water boil? 220 is the boiling-point of water? 220 causes a whispering gallery? 201 makes a wireless message go? 455 makes the works of a watch go? 368 makes the white caps on the waves white? 410 is worry? 207 causes the wind’s whistle? 139 makes the kettle whistle? 198 causes wrinkles? 196 are X-rays? 307 is yeast? 288

=When= did man first try to fly? 126 did man begin to live? 174 were candles introduced? 296 was illuminating gas discovered? 302 was wheat first used in making bread? 461 I throw a ball into the air, while walking why does it follow me? 401 was silk culture introduced in America? 111 were street lamps first used? 295

=Where= does bread come from? 460 does water in the ocean go at low tide? 219 does silk come from? 109 are we when asleep? 365 did the name calico come from? 123 cement is obtained (illus.), 97 does chalk come from? 18 does chocolate come from? 388 our coal comes from? 257 does cotton come from? 470 does the day begin? 324 does the day change? 325 did the term Dixie originate? 123 does honey come from? 526 is the horizon? 244 does the hour change? 325 the gas is taken from the coal (illus.), 299 did all the names of people come from? 20 did the expression “kick the bucket” originate? 321 does leather come from? 538 do living things come from? 174 did life begin on earth? 174 do we get ivory? 239 do lead pencils come from? 466 does the wooden part of a lead pencil come from? 469 does a light go when it goes out? 36 does linseed oil come from? 227 does paint come from? 224 does the rain go? 222 are the best Persian rugs made? 167 does rope come from? 353 does salt come from? 493 do we get soda? 494 do all the little round stones come from? 494 does the part of a stocking go that was where the hole comes? 64 does sound come from? 78 do school slates come from? 495 do shoes come from? 541 do sponges come from? 286 do tears come from? 94 do the tears go? 94 did the name tobacco originate? 512 is Havana tobacco grown? 513 does tobacco come from? 512 does tobacco grow? 512 did all the water in the ocean come from? 218 does our drinking water come from? 501 does most of our wool come from? 81 does the wind begin? 139 is the wind when it is not blowing? 139 does wool come from? 80 did the term Yankee originate? 243

=Wheat=, bread loaves of the world, 459 grinding (illus.), 464 harvesting (illus.), 460 scouring of, 463 tempering of, 463 when first used in making bread, 461 will it grow wild? 461

=Wheel-lock= rifle (illus.), 46

=Whispering gallery=, accidental, 201 cause of, 201 what it is, 201

=Whistle=, what makes the kettle? 198

=White Lead=, making (illus.), 225 buckles, before corrosion (illus.), 225 buckles after corrosion (illus.), 225 buckles, making, 225

=Who= started to make clothing from wool in America? 81 discovered electricity? 333 invented electric telegraph? 420 made the first felt hat? 239 made the first cent? 458 made the first submarine boat? 280 first discovered the silkworm? 109 first discovered the power of gunpowder? 44 invented flying? 126 made the first piano? 478 brought the first sheep to America? 80 first wove silk thread into cloth? 109 make the first shoes? 541 made the first umbrella? 312

=Why= don’t the air ever get used up? 140 can’t we see air? 140 do we grow aged? 196 does an apple turn brown when cut? 106 do coats have buttons on the sleeves? 64 has a long coat buttons on the back? 64 cannot babies walk as soon as born? 180 are some people bald? 144 don’t the birds stay South? 408 does a ball bounce? 63 does a balloon go up? 199 do we call voting balloting? 122 does a barber pole have stripes? 310 do some things bend and others break? 62 do the birds come back in the Spring? 407 do birds sing? 408 do birds go South in the Winter? 407 are birds’ eggs of different colors? 233 has a bee a sting? 336 can you blow out a candle? 21, 36 are bubbles round? 108 does red make a bull angry? 490 do we get a bump instead of a dent when we knock our heads? 201 can’t we burn stones? 105 has a long coat buttons? 64 is bread so important? 460 do I get out of breath when running? 191 do we call a cab a hansom? 122 does a hen cackle after laying an egg? 233 do children like candy? 409 is cement called Portland cement? 95 do I get cold in a warm room? 125 is it cold in winter? 141 does cold make our hands blue? 192 does an ear of corn have silk? 170 do we count in tens? 10 we cannot see in the dark, 91 does the dark cause fear? 352 do we have to die? 245 does a dog turn round and round before he lies down, 229 do we know we have dreamed when we wake up? 367 does eating candy make some people fat? 409 doesn’t an elevator fall? 397 do our eyes sparkle when we are merry? 92 do the eyes of some pictures follow us? 35 is it difficult to walk straight with my eyes closed? 91 do I get red in the face? 192 are some faculties stronger than others? 403 is a fire hot? 401 does a fire go out? 37 we fear the dark? 352 cannot fishes live in air? 232 do we have finger nails? 142 are our fingers of different lengths? 142 have we five fingers on each hand and five toes on each foot? 142 do we have finger nails? 142 does a gasoline engine go? 181 do girls like dolls? 368 is gold called precious? 266 are gold and silver best for coining? 457 is some gun-powder fine and others coarse grained? 206 are some guns called gatling guns? 310 does a glow-worm glow? 231 do we stop growing? 195 do we have hair? 143 does the hair grow after the body stops growing? 144 don’t my hair hurt when it is being cut? 143 does my hair stand on end when I am frightened? 143 is the right hand stronger than the left? 309 does my heart beat faster when I am scared? 191 does the heart beat when the brain is asleep? 191 do our hearts beat faster when we are running? 191 do they call it a honeymoon? 31 is a horseshoe said to bring good luck? 311 does it hurt when I cut my finger? 143 we cry when hurt, 93 does iron turn red when red hot? 107 does iron sink in water? 106 doesn’t an iron ship sink? 106 do we have twelve men on a jury? 239 does a lamp give a better light with the chimney on? 37 are there many languages? 197 do we laugh when glad? 92 is lead so heavy? 267 do they call them lead pencils? 466 must life be reproduced? 174 are some people light and others dark? 402 did people of long ago live longer than we do now? 199 do we use metal for coining? 456 do they call it the milky way? 255 do we need money? 455 does the moon travel with us when we walk or ride? 399 should we not sleep with the moon shining on us? 366 do my muscles get sore when I play ball in the spring? 310 does a nail get hot when hammered? 230 do we have only seven octaves on a piano? 480 does the ocean look blue at times? 219 does oiling the axle make the wheel turn more easily? 400 does an onion make the tears come? 38 can’t I write on paper with a slate pencil? 18 does a pencil write? 18 are some races white and others black, yellow and brown? 537 do they call it pin money? 231 do we call them pistols? 46 do plants produce seeds? 175 does a poker get hot at both ends if left in the fire? 107 does rain make the air fresh? 222 are most people right-handed? 403 don’t we make roads perfectly level? 104 don’t we use pure rubber? 380 does salt make us thirsty? 351 don’t the scenery appear to move when I am in a street car? 399 does the scenery appear to move when we are riding in a train? 399 can cats and some other animals see in the dark? 91 can we see farther when we are up high? 245 do I turn white when scared? 193 does silver tarnish? 266 does the sheep precede the plow in civilizing a country? 81 is the sky blue? 253 do I sneeze? 194 do we see stars when hit on eye? 268 many stars are there? 223 does a stick in water bend? 38 does a sound stop when we touch a gong that has been sounded? 78 can we make sounds with our throats? 78 do people shake with the right hand? 231 do we go to sleep? 365 does it seem when we have slept all night that we have been asleep only a minute? 366 can’t we sleep with our eye open? 92 we can hear through speaking tubes, 487 does a human being have to learn to swim? 125 are cooking utensils made of tin? 267 do we use copper telegraph wires? 266 do my teeth chatter? 218 are some things transparent and others are not? 350 do I laugh when tickled? 93 can we think of only one thing at a time? 193 does thunder always come after the lightning? 140 do we call them wisdom teeth? 125 are some roads called turnpikes? 104 is the sea water salt? 351 will water run off a duck’s back? 233 do we worry? 207 don’t the water in the ocean sink in? 219 is it warm in summer? 141 does water run? 219 do we say water is soft or hard? 221 does a piece of wood float in water? 106 do we wake up in the morning? 365 do I yawn? 173 does yeast make bread rise? 288