Replication of Coulomb's torsion balance experiment (Q2458888)

In 1785 Charles Augustin Coulomb, a retired military engineer, announced to the Paris Academy of Sciences, that he had invented an extremely sensitive instrument with which he claimed to have demonstrated that repulsion and attraction between bodies charged by electricity can be expressed by a similar expression like gravitational force of Newton's mechanics: \[ F_{e}\propto \frac{q_{1}q_{2}}{d_2} \] (where each \(q\) represents in this case electric charge). Since that time Coulomb was admired as helping physics to transform from a descriptive field to an experimental grounded mathematized science. Later many physicists produced Coulomb's torsion balance in various versions and tried to recapitulate Coulomb's experiments. But not all experiments succeeded. Some years ago the research team of Peter Heering at Oldenburg reported that in none of their experiments it was possible to obtain the results that Coulomb claimed to have measured. Now again A. A. Martinez of the University of Texas tried to recapitulate Coulomb's experiment. In all steps of his experiments he analyses Coulomb's prescription of 1785, trying to find the same material used in the 18th century -- and succeeded. A. A. Martinez summarizes: Coloumb ``was justified in his claim that he experimentally demonstrated what he confidentally called the `Fundamental Law of Electricity'''.