Bell Robin E. author Columbia University. Lamont-Doherty Earth Observatory Hansen R. O. author Columbia University. Lamont-Doherty Earth Observatory originator text Articles 1998 English Today elementary physics students take for granted such quantities as "big G," the universal gravitational constant. In fact in the late 1700s the value of this quantity was unknown, and the quest to determine it led to some of the earliest geophysical instrumentation. Just after the Revolutionary War in the United States, Cavendish developed the first system to measure the universal gravitational constant, the familiar "big G." Unfortunately, for geologists (at this time still mostly "gentlemen scientists"), this apparatus produced data which were difficult to interpret geologically, and it was far too large and cumbersome for field use. The geologic limitation was that the system only measured the horizontal derivative of a horizontal component of the gravity field, a quantity which by itself is difficult to interpret. Thus no applications of this elegant yet laboratory-bound instrument emerged. Geology Geophysics Petrology 17 1 81 83 1998-01 10.1190/1.1437836 http://hdl.handle.net/10022/AC:P:12547 NNC NNC 2012-02-13 15:40:03 -0500 2012-02-16 10:25:39 -0500 6552 eng