Ammonia, viii, 68-70; amines from, 215; atmospheric, i, 11, 13, ix, 269; boiling and freezing points, iv, 173; critical temperature and pressure, 173; density of, 113; discovery, xvi, 120; Gay-Lussac's studies, 133; in explosives, viii, 74, 75, 253; in fertilizers, 147, 253; in ice-making, v, 357, 358, 380, viii, 69, 70; in nitrogen cycle, 73; in sweat, ix, 276; metal test, viii, 288-9; name, 98; production, natural and artificial, i, 13, 35, 36, 153, viii, 46, 47, 68, 74, 75, 252, 253, 276, 278, xvi, 165; production and disposition in body, ix, 284-5, x, 279-80; refrigeration by, iv, 174, 187-8, viii, 69-70; solubility, 111 Ammonia Water, viii, 68, 147 Ammonites, iii, 275, xii, 75 Ammonium, viii, 93, 147; test for, 287, 289 Ammonium Compounds, viii, 147; carbonate, 137; hydroxide, 70, 121, 147, 288; nitrite, 121; salts, 147, 280; sulphide, 289 Amorphous, defined, viii, 374 Ampère, A. M., vi, 20-1; current unit named for, iv, 278; rule of magnetic deflection, 275 Ampere, electric current unit, iv, 278, 284, vi, 69, 70, vii, 361 (see also Electric Currents, Ohm's Law) Ampere-turns, iv, 288, vii, 362 Amphibians, iii, 285, xii, 167-81; age of, iii, 20; first appearance of, xv, 71; in oceanic islands, xiv, 278; relations to fishes and reptiles, iii, 284, 286, xii, 165, 183 Amphibole, iii, 321-3 Amphitheatres, mountain, iii, 66 Amphoteric, meaning, viii, 352 Amundsen, Capt., aeroplanes of, i, 46 Amyl Acetate, viii, 221 Amyl Alcohol, viii, 210, 214, 249 Amylases, viii, 357, x, 326 Amyloid, viii, 255 Anacondas, (boas), xii, 216 Anadromous Fishes, xii, 155 Anaërobic Bacteria, in peat production, xiii, 313; in sewage treatment, viii, 328 Analytical Chemistry, viii, 285-95 Analyzers, crystal, iv, 354 Anamnesis, x, 370 Anaphylaxis, x, 212-15, 223 Anatomy, Chinese systems of, x, 13; development of science of, 24, 30, 41-2, 44-5, 49, 51-2, 81, 116, 117, xvi, 82-3, 179-80 Anaxagoras, on origin of earth, ii, 366-7; theory of matter, xvi, 83, 118 Anaximander, theory of universe, ii, 367, xvi, 77-8 Anaximenes, theory of universe, ii, 366-7, xvi, 79 Andes Lightning, i, 149 Andes Mountains, glaciers of, xiv, 54; impassability, 250; lightning, i, 149; mineral wealth, xiv, 237; rivers, 167; snow pinnacles, i, 116-17; upraised in Cretaceous Period, iii, 219; volcanoes, xiv, 315; youthfulness of, 96, 235 Andrews, Thomas, i, 29, xvi, 175 Andromeda, nebula in, ii, 135-6, 136-7, 357, 361; new stars in nebula, 332-3 Anel, Dominique, x, 90-1 Anemia, x, 337; blood transfusion in, 338; cause and effects, xi, 370-1; of adolescence, x, 237; pernicious, discovery of, 112 Anemograms, i, 295, 366 Anemometers, i, 83-4, 366; for gusts, 295