Henry Cavendish's torsion balance experiment measured the tiny gravitational attraction between ordinary laboratory masses. Roland von Eötvös later tested a related question with high precision. What did the Eötvös experiment establish?

1. Cavendish's torsion balance experiment provided the first accurate measurement of G by weighing the attraction between ordinary sized masses. 2. Eötvös later asked whether one kilogram of lead attracts another mass exactly as strongly as one kilogram of water would. 3. Working to an accuracy of five parts per billion, he found that the gravitational force does not depend on the substance the masses are made of, only on their mass. 4. This result says nothing about G varying by location, and it directly rules out a substance dependence, so it cannot also mean gravity only acts between equal masses, a claim the inverse square law never made in the first place. _Source: OpenStax College Physics (CC BY 4.0), Ch 6 "Uniform Circular Motion and Gravitation", section 6.5 Newton's Universal Law of Gravitation_