Measuring the gravitational constant with the torsion balance

The use of the torsion balance to determine planetary motions is described, and its possible use in an attempt to determine the gravitational constant is discussed. A measurement using spheres of various weights shows that such a use is of questionable value, due to a dependence on the weights of the spheres, which should cancel in the calculations. The effect of the earth's gravity on the motion of the weighted spheres is addressed.