Part 132

=Dimples=, what causes, 352

=Discovery= of gunpowder, 44

=Discovery= of stringed musical instruments, 479 telephone, 71

=Diver’s= task made easy (illus.), 284

=Diving, deep-sea=, the telephone adjusting, (illus.), 202 cost of outfit, 203 hats of divers, 204 just before going down (illus.), 204 helmet, putting on (illus.), 202 shoes, putting on (illus.), 202 suit, putting on the (illus.), 202 suit, what consists of, 202 telephone from bottom, 203 telephoning, testing the (illus.), 203 testing final (illus.), 203 water pressure at varying depths, 203 wealth recovered by diving, 204 weight of outfit, 203

=Dixie=, what name means, 124 where name originated, 123

=Does= air weigh anything, 398

=Does= the air surrounding the earth move with it? 400

=Does= thunder sour milk, 196

=Does= light weigh anything? 37

=Does= the sun revolve on its axis? 511

=Do= father and mother plants always live together? 176

=Do= the ends of the rainbow rest on land? 254

=Do= the stars really shoot down? 255

=Dog=, why he turns round before lying down, 229

=Dolls=, why girls like, 368

=Dom Pedro=, Emperor of Brazil, who saved the telephone, 73

=Do= plants breathe? 241

=Draft=, created by chimney, 37

=Dreams=, cause of, 366 nightmare, 367 what makes us? 366

=Drinking=, origin of clinking glasses, 232

=Driving shield=, airlock bulkhead (illus.), 210 erector (illus.), 210 in tunnel building (illus.), 208 inventor of, 209 tunnels, front view (illus.), 209

=Ducks=, why water runs off backs of, 233

=Dust=, in air, 38 what it is, 104

=Dyeing=, silk, 121

=Earache=, what causes, 410

=Earth=, how big it is, 124 light surrounding, 38

=Echo=, what makes an, 200 whispering gallery, 201