Leaves, xiii, 32-43; absent in some plants, 15, 28, 30, 31, 99, 100; arrangement on stems, 38; branches as, 378, 379; buds of, 34; colors, 42; coloring in autumn, 79; coloring in tropics, 361; compound, 36-7; first, 60-1; forms and varieties, 34-6; fossils of, 302; functions, 37-8, 42, 61, 77-84; hairy covering, 104-5, 379; insect-capturing, 39-41; light and, 38-9, 87-90; large, examples, 189, 217, 359; moving, 105-6, 113, 114; none in fungous plants, 70; not decisive in family grouping, 184; of desert plants, 41-2, 106-7, 378, 379-80, xiv, 378-9; of evergreens and deciduous trees, xiii, 174, 175; of ferns, 63, 65; of monocotyledons and dicotyledons, 176, 178; osmotic pressure, 94; reproduction by division of, 165-6; rigidity of, viii, 338; shedding of, in dry periods, xiv, 369; skeleton (Madagascar yam), xiii, 90; sleeping, 88-9, 113; stems acting as, 28-31, 378; structure, 78-9; struggle for sunlight, 38-9, 87-90; tendrils on, 38; transitional form, 43; transpiration, 103, 104, 113, 374, 378, 379; uses, summarized, 42-3; veins, 32-3; water-dripping, 107-8; water-storing, 41-2, 106-7, 379-80; water-supply methods, 102-9; wilting, 102, 103, 114 Leblanc Process, viii, 276-7 Leclanche Cell, vi, 138 Lee, Dr. Willis T., i, 47 Lee, William, knitting machine of, v, 283 Leeches, xii, 51, 55-6 Leeuwenhoek, Antonius von, xvi, 107-8, 112 Legs, bones of, ix, 68-9, 70 (fig.); bones, growth, 56, 58; equal length, 169-70; evolution of, xii, 167; in insects, 102; length of men and apes, xv, 57, 59; muscles of, ix, 76; nerves of, 124-5; vestiges of, in snakes, xii, 213 Legumes, xiii, 56; nitrogen fixation by, viii, 74, 346, xiv, 66 Lehigh River, gap of, xiv, 51, 167 Leibnitz, mathematical work of, ii, 14, xvi, 105; monad theory, 117-18; scientific work, 113 Leif Ericson, xiv, 261 Lelande Cell, vi, 137, 139 Lemmings, xii, 290, 291 Lemon Oil, viii, 240, 252 Lemon Tree, origin, xiii, 225; scale on, xv, 22; spread, xiii, 354 "Lemuria", xii, 192 Lemurs, xii, 374-6; primates, 373; feet of, iii, 301 (fig.) Length, British units, iv, 45, 69, 283; measurements and standards, xvi, 130; metric units, iv, 46, 69, viii, 28 Lenoir Motor Car, v, 213 Lenses, iv, 337-8; achromatic, iv, 372-3, xvi, 125-6; Bacon's improvements, 101; for eye defects, ix, 111, 112, 113, 114; formation of images by, iv, 337-42, ix, 108-9; of eye, 109-11, 113 (fig.); refraction of light by, ii, 99 Lenticels, xiii, 26 Lenticular Clouds, i, 104, 376 Lentils, xiii, 198, 223 Lenz's Law, vi, 311, vii, 371 Leonardo da Vinci, anatomical work of, x, 51-2; astronomical work, ii, 41; idea of moving bodies, 63; views of fossils, iii, 14 Leonids, ii, 288