424 



Table S6S. 



ACCELERATION OF GRAVITY. 



For Sea Level and Different Altitudes. 



Calculated from U. S. Coast and Geodetic Survey formula, p. 134 of Special Publication No. 40 of that Bureau. 

 g = Q. 78039 (i + 0.005294 sin2 — 0.000007 sin^ 20) m 

 g =32.08783 (i -!■■ 0.005294 sin^c/) — 0.000007 sin2 24>) ft. 



To reduce log g (cm. per sec. per sec.) to log g (ft. per sec. per sec.) add log 0.03280833 = 8.5159842 — 10. 

 The standard value of gravity, used in barometer reductions, etc., is 980.665. It was adopted by the International 

 Committee on Weights and Measures in 1901. It corresponds nearly to latitude 45° and sea-level. 



Free-air Correction for Altitude. 



—0.0003086 cm/sec-/m when altitude is in meters. 

 —0.000003086 ft/secVft when altitude is in feet. 



Smithsonian Tables. 



