GEODETICAL TABLES. 



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



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



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



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



Duration of sunshine at different latitudes Table 87 



Declination of the sun for the year 1899 Table 88 



Duration of astronomical twilight Table 89 



Duration of civil twilight Table 90 



Relative intensity of solar radiation at different latitudes. 



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

 zontal surface at the top of the atmosphere .... Table 91 



Relative amounts of solar radiation received during the 



year on a horizontal surface at the surface of the earth Table 92 



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



sun Table 93 



Relative illumination intensities Table 94 



