It is not unusual to find books that erroneously describe Cavendish’s work as a measurement either of the gravitational constant (G) or the Earth’s mass, and this mistake has been pointed out by several authors. In reality, Cavendish’s stated goal was to measure the Earth’s density, and his result was later used to calculate G. The first time that this constant was used was in 1873, almost 100 years after the Cavendish experiment. Cavendish’s results also can be used to calculate the Earth’s mass.

— Wikipedia on Henry Cavendish

2010.08.16 Monday ACHK