Leopards, xii, 357; deer-hunting with, xv, 223 Lepidoptera, xii, 115-20; "blood rains" of, i, 358 Lepidosirens, xii, 142, 166 Leprosy, immunity and susceptibility to, xv, 50, 51 Lesions, meaning, x, 98, 322; X-ray treatment, vii, 253, 255-6 Lettuce, as food, ix, 27, 30; family, xiii, 206; origin, 223; wild, 105 Leucippus, theory of matter, xvi, 83, 84, 118 Leukaemia, metabolism in, x, 272 Leucocytes, germ destruction by, x, 209-10 Levees, effects of, xiv, 162 Level Changes, iii, 76-83, xiv, 33-6; due to earthquakes, iii, 97, 98; due to lateral pressure, 85; effect on erosion cycles, 36-7, xiv, 40, 163-4; shown by erosion of rocks, iii, 171-2 (see also Elevation, Rejuvenation, Subsidence) LeVerrier, astronomical work of, ii, 16, 79, 189, 269; meteorological work, i, 217, 228 Levers, v, 21-5; Archimedes on power of, iv, 25; classes of, remarks on, 89; clubs as, v, 12; friction in, iv, 93; legs as, v, 215; liquid, 97-103; mechanical gain in, iv, 41; primitive beginnings of, 24, v, 9, 14-15; principles shown by Archimedes, xvi, 89; revolving, v, 25-35 "Leviathan," steamship, v, 193-4 Leviathan Reflector, ii, 16-17, 105-6 Levulose, viii, 226, 248 Lewis & Clarke reports, xvi, 171 Lewis Machine Gun, v, 365-6 Lex Talionis, xv, 371 Leyden Jar, iv, 267, 368 (fig.), vii, 259, 260; discovery and experiments, xvi, 188-9; oscillations of, iv, 313 Lianes, xiii, 362, 363, 366 Liberty Engines, v, 53-4 Libyan Cat, xii, 355 Libyan Desert, rain in, i, 210 Lichens, species, xiii, 323 Lick Observatory, ii, 142-4, 148 Licorice Plant, leaves, xiii, 113 Liebig, Justus von, x, 126; chemical work, xvi, 162; on fermentation, x, 138-9 Liège, siege of, xiv, 92