In the earth* s crust, the existence and magnitude 
scientific phenomena. In survey prospecting for 
and 
(anticlines, faults, etc.) and 
lent rocks, etc.. and favoral 
logical factors. In civil engineering, it is used more and more in the 
studies of foundation for dam sites, railroads, various heavy struc- 
tures. It is probable that a biologist, paleontologist, and anthropologist 
might find of some interest to study the maximum variations in the 
force of gravity due to changes in altitude, topography, etc., and their 
influences on the survival of certain species. 
prospecting for local gravitational 
Bouguer, terrain, regional 
daily variation corrections to the observed gravitational 
ration. 
surveys 
The Study of Possible Maximum Variations - To obtain the 
xiidximum possible variations of the force of gravity at the earth's sur 
face, we must reverse the procedure which is usually used in gravita- 
tional prospecting and add or subtract to the gravity values referred to 
the "Normal Spheroid" (the "International Ellipsoid"), the necessary 
corrections. These corrections are: free air, Bouguer, terrain, dailj 
variations, regional, isostatic, and local anomaly. To emedite the coi 
that 
cannot 
majority of cases, + 300 milligals. Terrain corrections should 
many poorly dissected territories, 
gravity may be negligible. Bouguer 
their 
points located above 
tions may introduce considerable error. 
the aoplication of the Bougue 
In evaluating 
the following assumptions have been made: 
Density of basement rocks under the oceans = 
Average density of sea water - 1.00 
Change in gravity per 1 meter of height at any 
Bouguer corr( 
5 = Density 
mgals 
gals, per meter where 
5 
