Coulomb’s Torsion Balance
Coulomb’s torsion balance had no means to measure the amount of charge he had induced in the apparatus. He only new that the charge was the same on both charged objects.
In 1785 Charles-Augustin de Coulomb published the results of a series of experiments designed to measure the electric and magnetic forces between charged objects using an instrument of his own design — the torsion balance¹. The scientific world had been swooning over Newton’s Principia for the past 100 years which had the effect of putting William Gilbert’s earlier work on magnetism and Charles Dufay’s, and Stephen Gray’s work on static electricity (contemporary to Newton’s work on gravity) on a back burner. None the less, over the course of those hundred years, some progress was made. The Germans had introduced the Leyden jar, an early form of capacitor, and the Americans had redefined Dufay’s two types of electricity, vitreous and resinous, more generally as negative and positive².
Newton’s Principia had established the notion that natural philosophy could be firmly rooted in mathematics using balanced equations and, of course, it was the Calculus, the new math, that would make it all possible. The electricians (which is what they called themselves) were somewhat less convinced that Newton’s…
