constant did not become standard until long after Cavendish's time. Indeed, one of the first references to G is in 1873, 75 years after Cavendish's work. Cavendish expressed his result in terms of the density of the Earth. For this reason, historians of science have argued that Cavendish did not measure the gravitational constant. He referred to his experiment in correspondence as 'weighing the world'. Later authors reformulated his results in modern terms. After converting to SI units, Cavendish's value for the Earth's density, 5.448 g cm−3, gives G = , which differs by only 1% from the 2014 CODATA value of . Today, physicists often use units where the gravitational constant takes a different form. The Gaussian gravitational constant used in space dynamics is a defined constant and the Cavendish experiment can be considered as a measurement of this constant. In Cavendish's time, physicists used the same units for mass and weight, in effect taking g as a standard acceleration. Then, since R was known, ρ played the role of an inverse gravitational constant. The density of the Earth was hence a much sought-after quantity at the time, and there had been earlier attempts to measure it, such as the Schiehallion experiment in 1774. For these reasons, physicists generally do credit Cavendish with the first measurement of the gravitational constant. Derivation of G and the Earth's mass The following is not the method Cavendish used, but describes how modern physicists would calculate the results from his experiment. From Hooke's law, the torque on the torsion wire is proportional to the deflection angle of the balance. The torque is where is the torsion coefficient of the wire. However, a torque in opposite direction is also generated by the gravitational pull of the masses. It can be written as a product of the attractive forces between the balls and the distance to the suspension wire. Since there are two pairs of balls, each experiencing force F at a distance from the axis of the balance, the torque is LF. At equilibrium (when the balance has been stabilized at an angle ), the total amount of torque must be zero, as these two sources of torque cancel out. Thus, we can equate their intensities given by the formulas above, which gives the following: For F, Newton's law of universal gravitation is used to express the attractive force between the large and small