POSSIBLE MAXIMUM VARIATIONS IN THE FORCE OF GRAVITY 
AS MAY BE OBSERVED AT THE EARTH'S SURFACE 
by V. G. Gabriel* 
Abstract - The earth and its ideal mathematical represen- 
tation, a spheroid of revolution, are briefly defined in terms of radii 
and other parameters of the earth. The force of gravity at the earth's 
surface is defined with the use of Newton's law of universal gravitation 
and Free-Air Gravity, Bouguer gravity, Isostatic compensation, etc., 
are briefly e^lained. The use of gravimetric measurements in scien- 
tific research and in exploration for oil and metals are briefly discus- 
sed. 
With 
combined effect of the theoretical gravity values referred to the Inter- 
national Ellipsoid and the maximum gravity deviations due to altitude, 
the Bouguer, isostatic. and other necessarv corrections, are evaluated 
Curve," 
given. 
Gravity 
examples for the evaluation 
The erravitv observations 
face of the earth with the use of various gravitational devices, such as 
pendulums, gravimeters, and the Torsion Balance in the past, have 
played a larger and larger part in the study of the earth, both its crus- 
tal and subcrustal layers. In the last three decades however, the use of 
gravitational methods has been extended to the study of dam sites, rail- 
road and building foundations, and to the search for oil and metals lo- 
cated, figuratively speaking, in the skin of the earth, that is, in the upper 
crust 
the fundamental 
property of matter to possess a certain mass and on the ability 
various gravitational instruments of responding to this property, or its 
^ * Geology Department. Missouri School of Mines and 
'^^etallurgy, u. of Missouri. Rolla, Missouri. 
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