  We determined the Newtonian Constant of Gravitation G by interferometrically
measuring the change in spacing between two free-hanging pendulum masses caused
by the gravitational field from large tungsten source masses. We find a value
for G of (6.672 34 +/- 0.000 14) x 10^-11 m^3 kg^-1 s^-2. This value is in good
agreement with the 1986 Committee on Data for Science and Technology (CODATA)
value of (6.672 59 +/- 0.000 85) x 10^-11 m^3 kg^-1 s^-2 [Rev. Mod. Phys. 59,
1121 (1987)] but differs from some more recent determinations as well as the
latest CODATA recommendation of (6.674 28 +/- 0.000 67) x 10^-11 m^3 kg^-1 s^-2
[Rev. Mod. Phys. 80, 633 (2008)].
