Lighting Systems, color effects, iv, 370; exterior, vi, 278-83, vii, 339-43; interior, vi, 275-8, vii, 68-72 Lightning, i, 146-57, vii, 201-19; annual deaths by, x, 254; awe-inspiring power, vii, 201, 202; causes, i, 149-52, iv, 269, vii, 206-15, 217-8; current strength, i, 152-3; danger and protection, 155-7, vii, 201-2, 218-19; danger in aeronautics, i, 303; defined, 376, vii, 371; displays, 203; distance, how determined, i, 187, vii, 210; electromagnetic waves from, 260; fire from, xv, 320; Franklin's experiment, i, 141, vi, 10-11, 14-16, vii, 204-5; large raindrops and, 215-17; multiple flashes, i, 146-8; nitrogen fixation by, 13, 34-5; oscillations, vii, 208, 366, 374; ozone produced, i, 15; photographic study, 146-8, 151; protection of electric lines, vii, 16-19, 49-50; thunder from, i, 192-3, vii, 210-11; types, i, 146, 148-9, vii, 205-6, 211-15; visibility, i, 152; voltage, 151-2, vii, 206-7; weathering agency, iii, 24; wind effects, i, 148 Lightning Arresters, vii, 17-18, 49-50, 362, 371 Lightning Prints, i, 154-5, 376 Lightning Rods, i, 156-7, 376, iv, 270, vii, 218-219, 371; invention, i, 141, vi, 14, 16; principle, vii, 209; use of points, vi, 297 Light-Pillars, i, 376 Light Waves, iv, 353, vi, 118-19, 269; atmospheric effects, i, 165-6, 170-1; caused by molecular vibrations, iv, 360, 363, 379; Doppler's principle, ii, 119, iv, 210; glass and, 183; interference of, 376-8; length and frequency, vii, 250, 260; length and frequency with different colors, iv, 359, 360, 365, ix, 114, 115; motion of, xvi, 137; unit of length, iv, 359, xvi, 130 Light-Year, ii, 315, xvi, 33 Lignite, iii, 344, 345, 346, 347, 348, viii, 44, 45 Lilac, fertilization, xiii, 143-4; leaves, 38 Lilienthal, Otto, v, 231 Lily, African, xiii, 38; leaves, 38, 176 Lily Family, xiii, 183-4 Lily of the Valley, xiii, 45, 47, 178 Lima Beans, variation in, xiii, 331 Limacina, xii, 19 Lime, calcium oxide, viii, 149; in earth's crust, iii, 308; in water, viii, 40, xiv, 142, 147; production, iii, 373, viii, 150, 276; slaking of, 38-9; uses, iii, 373, viii, 149-50, 278, 323, 347 Limes (fruit), origin, xiii, 225; spread, 354 Lime Salts, body needs of, ix, 32, 33, 33-4, 174; in bone, 57; in diet, x, 256