412 



INDEX 



Force, 333, 335 



centrifugal, 392 



centripetal, 393 

 Friction, 337 



rolling, 337 



sliding, 337 

 Fuel, burning elements of, 179 



economy of, 177 



heating value, 178 



kinds of, 176, 202 



sources of, 176 

 Fulcrum, 334, 335 

 Fungi, 317 



types of harmful, 317, 318, 320 

 Fuses, 368 



Games, 383, 393 

 Gardening, cultivation, 301 



indoor, 292 



science in, 298 



spraying, 327 



value of birds, 328 

 Gas, advantage of mantle, 245 



desirability of, 245 



fishtail flame, 245 



flame, luminous and non-luminous, 199 



in the home, 244 



meter, 201 



range, 199 



Gasoline, treacherous cause of fire, 211 

 Germ dangers, 158 

 Germs, see Bacteria 



growth of, 159 

 Glass, importance of, 270 

 Granite quarry, 270 

 Graph, showing temperature, 22 

 Grasshoppers (Orthoptera), 323 

 Grease, removal of, 235 

 Grounds, planning of, 286 

 Gyroscope, 391, 392 



Hay fever, 69 



Head, related to insect, 319 



Health, body poisons, 166 



exercise and, 167 



rest and, 169 



rules of, 34, 172 

 Hearing, 376 

 Heart, 145 

 Heat, 51 



distributing, 185 



from electricity, 247, 355 



Heat Continued 



heat travels, 186 



in homes, 196 



loss from body, 221 



relation to energy, 52 



steam, 196 



sun, source of, 51 

 Hemiptcra, 323 

 Home, 270 



beginnings of, 25 



choosing 27, 28, 274 



duties of children at, 33, 168 



efficiency in, 32 



electricity in, 360 



environment of, 55 



grounds of, 287 



grounds surrounding, 286 



heating of, 189 



ideal, 27 



ideal location and drainage, 28 



ideal score card, 36, 37 



motors in, 352 



recreation in, 33 



regulation of light in, 241, 243 



removal of wastes, 146 



requirements, 27 



scoring of, 35 



suburban, 25 



use of color in, 277 



water supply in, 80 

 Hot-air furnace, 191, 192 



advantages and disadvantages 



193 



Hotbed, use of, 310 

 Hot- water heating system, 194 



advantages and disadvantages 



iQS 



how a room is warmed, 194 



principle of, 193 

 Hot water, supply of, 200 

 House, floors of a well-planned, 275 

 Humus, 50 

 Hydrogen, 93 



burning, 180 



Iceless refrigerator, 124 

 Ichneumon flies, 327 

 Imago, 320 



relation to butterfly, 320 

 Immunity, 163 



antitoxin treatment, 163 

 Impervious layer, 77 



of 



of, 



