IKDEX 



Dams, 135, 136*, 801 



Danger of electrical injuries, 233 



Day, length of, 36* 



Daylight saving, 37 



Death rate from disease, 102, 104 

 160, 161 



Decomposition, chemical, 68* 



Deforestation and erosion, *305-307 



Delphinus, 273 



Densities, 139-140 



Dependent plants, 83*, 84*, 91* 



Desert-plant formations, 316* 



Dew point, 26 



Diastase, 331, 332 



Diffusion, 69, 62 



Digestion, 332, 357, 358 ; and exer- 

 cise, 342 



Diphtheria, 95 



Disease, destruction by, 379 ; and 

 cleanliness, 107 ; means of protec- 

 tion against, 99 



Disease germs distributed by insects, 

 112 



Distillation, 117-118* 



Diving bell, 6 



Dodder, 84* 



Drainage, *294-303 



Drainage canal of Chicago, 104 



Dry cell, 200, 201*, 202 



Dry farming, 302 



Dunes, 310* 



Dust, 87-91 



Earth, crust of, *279-314 ; orbit of, 

 34*, 265 ; in relation to other as- 

 tronomical bodies, *243-279 ; sur- 

 face of, 279-280* 



Earthworms and soil, 291 



Ebony, 140 



Eclipses, 249, 250*, 251 



Efficiency, 182 



Electric advertising signs, 212 ; bells, 

 202*, 236 ; circuits, 199, *201-203 



Electric currents, chemical effects 

 of, *21 7-223; effect of, on wires, 

 197; heat and light from, 195- 

 197 ; magnetic effect of, *224-242 



Electric heating devices, cost of 

 operating, 212 ; use of, 211-212 



Electric lamp, uses of, 213-214 



Electric motor, *231-233 



Electricity, *1 73-242; magnetic 

 effects of, 227, 228*, 231* 



Electromagnets, 228* ; uses of, *229- 

 231 



Elements, 68 



Elevation and air pressure, 11, 12, 13* 



Embryo plant, 372 



Energy, *1 72-242, *183-194 ; capac- 

 ity of, for doing work, 183 ; kinds 

 of, 184 ; kinetic, 190 ; and life 

 193-194 ; loss of, 190-191 ; meas- 

 urement of, 185 ; mechanical, 

 *183-194; potential, 190; source 

 of, 191 ; source of, for plants, 82 ; 

 from the sun, 192-193; transforma- 

 tions of, 185, 190; and work 

 193-194 



Engine, *187-190 



Environment, changes in, 388-389 ; 

 control of human, 395 



Enzymes, 332, 338 



Epidermis of leaf, 79* 



Erie Canal, 157 



Erosion, *304-311 ; and craters, 247 ; 

 and deposit, 309 ; loss from, 306 ; 

 on the moon, 247 ; by plants and 

 animals, 285-280* ; and vegetation, 

 *307-308 ; by wind, *309-311 



Ether, 119; and evaporation, 121 



Evaporation, 21, 119-122, 125-126; 

 cooling effects of, 120-122; from 

 plants, 125-126; rate of, *124-125 



Exercise, and digestion, 342 ; value 

 of, 362 



Factory, plant compared to, 85 



Fahrenheit thermometer, 14, 15* 



Farm wells, purity of, 170 



Fat, manufacture of, 85 



Fats, 329, 330 



Faucets, types of, 165* 



Fermentation, 89* 



Filtering plants, 165 



Fire engine, 132 



Fire extinguisher, 72 



Flame, products of, 65*, 70, 71; 

 structure of, 64*, 65* 



Flea and bubonic plague, 112 



Floating objects, 137* 



Flood warnings, 56 



Flower, 369-372 



Fluorine, 69 



Flush tanks, types of, 166* 



Food, amount needed, 358-359 ; and 

 body temperature, 344; contami- 

 nated 359; and filth, 360; lack 

 of sufficient, 277-278; necessity 

 of, 336; preparation for absorp- 

 tion, 338-339 ; preservation of, 94 ; 



