Part 136

=Gunpowder=, Chinese probable discovers of, 44 discoverer of, 44 experiments by Schwartz, 45 formula of Roger Bacon, 45 ingredients in, 205 manufactured in monasteries, 44 what causes the smoke? 206 smokeless, what made of, 206 why some is fine and others large grained, 206

=Gurgle=, in bottles, 63

=Hail=, what causes, 124

=Hair=, what causes baldness, 143 why it don’t hurt when cut, 143 why it keeps growing, 144

=Hand bombards=, early types, 45

=Hands=, shaking, why with the right, 231

=Hansom=, why so called, 122

=Have= plants fathers and mothers? 175

=Heart=, why beats during sleep, 191 why beats faster when scared, 191 why beats faster when running, 191

=Heat=, light wave changed into, 36 why a nail gets hot when hammered, 230 why some things are warm, 144 how we obtain, 231

=Hemp=, Manilla (illus.), 356

=Hobson’s choice=, how originated, 311

=Honey=, apiary in summer (illus.), 534 how produced, 527 worker comb (illus.), 532 manner of using German bee-brush, 533 finished product (illus.), 533 frame (illus.), 535 how to bump the bees off a comb (illus.), 533 bee-hat (illus.), 535 a study in cell-making (illus.), 532 bee sting, can a, 536 frame of bees (illus.), 535 comb, how bees build, 536

=Honey-bee=, poison-bag, 537 egg of queen, under microscope (illus.), 529 preparing for rearing, 531 living on combs in open air, (illus.), 527 the daily growth of larvæ (illus.), 532 effect of a sting (illus.), 536 worker-bee (illus.), 527 what the queen-bee does? 528 drone-comb (illus.), 532 clipping queen bees wings (illus.), 533 cucumber blossom with bee on it (illus.), 528 queen-bee (illus.), 527 the queen and her retinue (illus.), 529 queen-rearing, 531 queen-cells (illus.), 529

=Honeymoon=, why do they call it a? 311

=Horizon=, how far away is the, 245 what is it, 244 where is it, 244

=Horse-power=, a, what it is, 256

=Horseshoes=, why it is said to bring good luck? 311

=Hot box=, cause of, 368

=Houiller=, French gunsmith, 48

=Houses=, concrete (illus.), 101

=How= far does the air extend? 243 is ammunition made (illus.)? 49 does an arc light burn? 307 are automobile tires made? 382 does a honey bee live? 336 does a bee make honey? 527 do bees build the honey comb? 536 does the honey bee defend itself? 536 does honey develop in a comb (illus.)? 530 do birds learn to fly? 178 do birds find their way? 407 does the blotter take up the ink of a blot? 18 this book is bound, 578 this book is made, 561 the paper in this book is made, 561 the pictures in this book are made, 581 are bullets made? 51 is an ocean cable laid? 429 does a camera take a picture? 22 is a cable dropped into the ocean (illus.)? 432 are modern carpets made? 169 is a carpet woven by machinery? 171 is china decorated? 406 is china made? 404 is chocolate made? 392 did the custom of clinking glasses in drinking originate? 232 are cigars made? 517 is cloth made from wool? 86 did the coal get into the coal mines? 257 does a coal mine look inside? 260 do the cocoa beans grow (illus.)? 391 is the color put on the outside of the pencil? 469 is the honey comb made? 532 are concrete roads built (illus.)? 103 did man learn to cook his food? 308 are concrete buildings made (illus.)? 100 is woolen cloth dyed? 87 big is the earth? 124 much of the earth does the sun shine on at one time? 324 does an elevator go up and down (illus.)? 396 was electricity discovered? 333 does the light get into the electric bulb? 305 is the eraser put on a pencil? 469 can an explosion break windows? 62 explosions may occur on submarines, 278 does the farmer use concrete (illus.)? 102 do our finger prints identify us? 520 did man learn to fight fire? 308 did man learn to make a fire? 289 are fishes born? 177 was the flag made? 310 is flour made? 462 does a fly walk upside down? 454 did men learn to fly? 126 does the gas get into the gas jet? 302 is illuminating gas made? 303 is gas purified? 303 is plate glass made? 246 is plate glass ground? 250 a wire-wound gun is made? 54 was the first American gun made (illus.)? 47 is a gun ingot made? 55 do we find the length of a gun? 53 is a gun tube tempered? 57 do we obtain heat? 231 the heel of a shoe is put on (illus.), 560 did Hobson’s choice originate? 311 far away is the horizon? 245 does a key turn a lock (illus.)? 491 does a spring lock work (illus.)? 492 are lead pencils made? 467 do the miners loosen the coal? 261 is light produced, 230 are magnets made? 335 are matches made? 293 are match boxes made? 294 did man learn to send messages? 412 does the meter measure the gas? 304 can microbes spread through the body? 410 are mirrors silvered? 522 big is a molecule? 348 did money originate? 455 are moving pictures made? 369 does the music get into the piano? 478-482 did the word news originate? 312 did a nod come to mean yes? 19 did shaking the head come to mean no? 19 are paints mixed? 228 is a photograph developed? 23 was the piano discovered? 479 do plants breathe? 241 do plants reproduce life? 175 does the shield cut through the ground in tunnel building? 212 are shooting shells photographed? 24 shoes are made by machinery, 549 shoe machinery was developed, 457 is crude rubber secured? 377 is rope turned and twisted? 358 are rubber tires made? 378 are modern rugs made? 169 to splice a rope, 364 do men go down to the bottom of the sea? 202 did the sand get on the seashore? 108 far back does the silkworm date? 109 was silk introduced into Europe? 110 are the silkworms cared for? 113 do we know a thing is solid, liquid or gas? 348 are sounds produced? 485 fast does sound travel? 486 can sound come through a thick wall? 79 is the volume of sound measured? 242 far does space reach? 256 do the slate pickers work? 259 does a captain steer his ship across the ocean? 407 can a ship sail under water, 269 is a submarine submerged? 270 do sponges grow? 286 do sponges eat? 287 are sponges caught? 287 are the stars counted? 241 big is the sun? 141 hot is the sun? 141 is a steel pen made (illus.), 17 did man learn to shoot, 40 do we get wool off the sheep? 82 is a stone thrown with a sling? 41 are metallic and paper shells filled with powder? 50 did man learn to talk? 18 did the telephone come to be? 70 fast does thought travel? 242 does a telegram get there? 414 did man learn to tell time? 313 did man begin to measure time? 314 did men tell time when the sun cast no shadows? 317 is the time calculated at sea? 315 is tobacco cultivated? 516 is tobacco cured? 516 was tobacco discovered? 512 is tobacco harvested? 515 is tobacco planted? 514 is a tunnel dug under water? 208 does water put fire out? 222 is white lead made? 225 are wires put under ground? 76 did writing first come about? 11 did the Chinese write? 13 did the Monks do their writing? 14 does a pen write? 18 much does the wool in a suit of clothes cost? 83 much wool does America produce? 82 is wool taken from the sheep? 82 is the yarn for carpets dyed? 170 is oxide of zinc obtained? 226 does the water get into the faucet? 501 are the big water pipes laid? 504 did the name Uncle Sam originate? 458

=Human body=, wonders of the, 311

=Hunting=, with the bow-and-arrow, 43

=Hurt=, why we cry when, 93

=Hydrogen=, what it is, 349

=Hypo=, used in developing, 23

=Impact=, of projectile from guns, 28