i65 

 169 

 170 



173 

 175 

 176 

 177 



Xll TABLE OF CONTENTS. 



rp HYGROMETRICAL TABLES. PaGE 



74 Pressure of aqueous vapor over ice. English measures . . . . 164 



75 Pressure of aqueous vapor over w^ater. English measures 



76 Pressure of aqueous vapor over ice. Metric measures . 



77 Pressure of aqueous vapor over water. Metric measures 



78 Pressure of aqueous vapor over ice. Dynamic measures 



79 Pressure of aqueous vapor over water. Dynamic measures 



80 Weight of a cubic foot of saturated vapor. English measures 



81 Weight of a cubic meter of saturated vapor. Metric measures 

 Reduction of psychrometric observations. English measures — 



82 Values of e = e' -o.oooT^GyBit-t') f 1+ ~^^ \ .... 180 



83 Relative Humidity. Temperatures Eahrenheit 191 



Reduction of Psychrometric Observations. Metric measures — 



84 Values of ^ = £?' — o.ooo66o5(/; — ^') (i +0.00115^') .... 194 



85 Relative humidity. Temperature Centigrade 200 



86 Rate of decrease of vapor pressure with altitude for mountain 



stations 202 



Reduction of snowfall measurements — 



87 Depth of water corresponding to the weight of a cylindrical 



snow core 2.655 ii^ches in diameter 202 



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



rain) collected in an 8-inch gage 203 



89 Quantity of rainfall corresponding to given depths 203 



GEODETICAL TABLES. 



90 Value of gravity on the earth at sea level 206 



91 Relative acceleration of gravity at different latitudes .... 207 



92 Length of one degree of the meridian at different latitudes . . . 209 



93 Length of one degree of the parallel at different latitudes . . . 210 



94 Duration of sunshine at different latitudes 211 



95 Declination of the sun for the year 1899, at Greenwich apparent 



noon 222 



96 Duration of astronomical twilight 223 



97 Duration of civil twilight 224 



Relative intensity of solar radiation at different latitudes — 



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



zontal surface at the top of the atmosphere 225 



99 Relative amounts of solar radiation received on a horizontal 



surface during the year at different latitudes .... 226 

 100 Air mass, m, corresponding to different zenith distances of the sun 226 

 loi Relative illumination intensities 226 



