X TABLE OF CONTENTS. 



Table Page 



79 Rate of decrease of vapor pressure with altitude for mountain 



stations 194 



Reduction of snowfall measurements — 



80 Depth of water corresponding to the weight of a cylin- 



drical snow core 2.655 inches in diameter 194 



81 Depth of water corresponding to the weight of snow (or 



rain) collected in an 8-inch gage 195 



82 Quantity of rainfall corresponding to given depths 195 



GEODETICAL TABLES. 



83 Value of apparent gravity on the earth at sea level . . . . . 198 



84 Relative acceleration of gravity at different latitudes .... 199 



85 Length of one degree of the meridian at different latitudes . . 201 



86 Length of one degree of the parallel at different latitudes . . 202 



87 Duration of sunshine at different latitudes 203 



88 Declination of the sun for the year 1899 214 



89 Duration of astronomical twilight 215 



90 Duration of civil twilight 216 



Relative intensity of solar radiation at different latitudes — 



91 Mean intensity for 24 hours of solar radiation on a hori- 



zontal surface at the top of the atmosphere . . . . 217 



92 Relative amounts of solar radiation received on a horizontal 



surface during the year at the surface of the earth . . 218 



93 Air mass, m, corresponding to different zenith distances of the 



sun 218 



94 Relative illumination intensities 218 



MISCELLANEOUS TABLES. 



Weight in grams of a cubic centimeter of air — English measures — 



95 Temperature term 220 



96 Humidity term, auxiliary table . . 221 



97 Humidity and pressure terms, combined 222 



Weight in grams of a cubic centimeter of air — Metric measures — 



98 Temperature term 224 



99 Humidity term, auxiliary table 225 



100 Humidity and pressure terms, combined 226 



101 Atmospheric water-vapor lines in the visible spectrum .... 229 



102 Atmospheric water-vapor bands in the infra-red spectrum . . 230 



103 Transmission percentages of radiation through moist air . . . 231 



104 International meteorological symbols 232 



105 International cloud classification 234 



106 Beaufort weather notation 236 



107 List of meteorological stations 237 



Index 259 



