Life, the atmosphere in relation to beginnings of, 2, 3; thinness of stratum of air that sustains, 14; how to prolong, 246; in the open air and sunshine, 247-249 Light, slight refraction of, in higher altitudes, 9; diffused by dust motes, 45; source of, 49; how it reaches the earth, 49; a manifestation of solar energy, 49; invisible, 52, 53; and transparency, 56; speed of, 162; from the stars, 162 Light waves, difference between heat, sound, and, 51; length of, 51; velocity of, 51, 52; and invisible light, 52, 53 Lining, Dr. John, temperature records kept by, 293 Liquid air, 9 Local forecasting, rules for making, 153-155 Lofoten Islands, temperatures recorded in the, 196 London, England, Christmas Day in, 269, 270 Loomis, Elias, 296 Los Angeles, Cal., climate of, 210; meteorological statistics for, 262 Lows, the initiation of, 101; placing of, on the weather map, 115, 116; characteristics of, 124; their influence on cold waves, 126; conditions and action of air of, 131-133; periodicity of, 132; and warm waves, 136; V-shaped, 137; influence of certain, on climate, 192-194 Lunar halos, 141 Macready, Lieut. John A., altitude record of, 20 Mammoth Cave, temperature of, 181 Man, climate and the dominant races of, 213-224; conditions best suited to health, strength, and efficiency of, 215, 216; excessive humidity harmful to, 216, 217; semi-annual maximum and minimum periods of efficiency of, 217, 218 Manila, P. I., climate of, 255 Maritime interests, benefits of Weather Bureau service to, 300-303 Marvin, Prof. Charles F., present chief of Weather Bureau, 306 Matter, early belief as to construction of all, 30; present knowledge of nature of, 31; determination of differences in, 31; forms of simple, 31 Maury, Matthew F., 298 Mazatlan, Mexico, climate of, 209 Mediterranean Sea, temperatures of waters of, 177 Melbourne, Australia, Christmas Day in, 275 Mental activities, and weather conditions, 215, 216 Mercury, density of, compared to air, 15; nucleus of atom of, 32 Mesopotamia, former fertility of, 234, 235 Meteorological conditions best suited to efficiency of man, 216 Meteorological science, in America, 291-306. _See_ also UNITED STATES WEATHER BUREAU Meteorological station, instruments installed in, 63 Meteorological statistics, tables of: for Los Angeles, Cal., 262; for Miami, Fla., 262; for Jacksonville, Fla., 263; for San Diego, Cal., 263; for Tampa, Fla., 264; for Bermuda, 264 Meteorologists, association of aviator with, in map making, 23 Meteors, cause of luminosity of, 6 Meyer, Gen. Albert J., inaugurates tentative weather service, 305 Mexico City, climate of, 209, 210 Miami, Fla., temperature and rainfall at, 261; meteorological statistics for, 262