INDEX 



4S 



Drinking cup, 197 



Drugs, 191-195 



Dry cells, 209 



Ducks, 464 



Dunes, 38^-391 



Dust, 388 



Dyeing, 138-139, 168-172 



designs, 171-172 



indirect, 170-171 



mordanting, 170171 

 Dyes, aniline, 103-104, 169 



coal tar, 103-104, 138-139, 169 



selection of, 169-170 



vegetable, 103, 138, 168-169 

 Dynamo, 236 



Earth, crust, 409-416 



motion, 396-399 

 Earthquakes, 410-411 

 Echo, 282-283 

 Economy, in buying food, 77-79 



in cooking, 37-38 

 Electricity, battery, 2IO 



bell, 218-220 



bulbs, 213 



conductors of, 22O 



cost of, 238-239 



dry cell, 209 



how obtained, 234-235 



lighting, 213, 280 



magnetic properties of, 217-219, 228, 

 230 



resistance of, 213-214 



source of heat, 210-213 



terms used in, 209 



useful devices, 211-213, ^33 



voltaic cell, 207-209 

 Electrodes, 209 

 Electromagnet, 217-219 

 Electromotive force, 209 

 Electroplating, 214-215 

 Emulsion, of soap, 144, 145 

 Energy, conservation of, 65-68 

 produced by carbohydrates, 71 



sources of, 309-310 



Engines, gas, 317-318 



steam, 316-317 



Environment, geographic, 393-396 

 Erosion, 362-364, 375~3?6, 39^ 

 Eskimo, 250, 394~396, 39 8 

 Ethyl butyrate, 102 

 Evaporation, and chills, 43 



and humidity, 42 



and winds, 401-402 



cooling effects of, 41-42, III 



dew point, 43 



from plants, 351 



heat required for, 41 

 Expansion, advantage and disadvan- 

 tage of, 15-17 



of air, 14-15 



of liquids, 13-14 



of solids, 14 



of water by freezing, 46, 48-49 



of water by heat, 13-14 

 Eyes, 258-261 

 Eyestrain, 261 



caused by poor illumination, 247-251 



headache from, 260-261 



in arctic regions, 250 



Fabrics, 130-135 



dyeing of, 168-172 



frauds in, 135136 



printed designs on, 171-172 

 Fahrenheit thermometer, 19 

 Farsightedness, 259-260 

 Fats, 71 



digestion of, 95 



use in soap making, 143 

 Felt, 137 



Fermentation, 153-157 

 Fertilizer, artificial, 188 



made from sewage, 190, 203-204 



manure, 190 

 Fibers, cotton, 131-132 



hemp, 457 



jute, 457 



leaf, 458 



linen, 132-133 



