Charles François de Cisternay du Fay

Charles François de Cisternay du Fay (14 September 1698 – 16 July 1739) was a French chemist and superintendent of the Jardin du Roi. He discovered that some charged items would repel while some would attract and posited the existence of two types of electricity and named them "vitreous" and "resinous" (in fact he had discovered positive and negative charge, respectively) He noted the difference between conductors and insulators, calling them 'electrics' and 'non-electrics' for their ability to produce contact electrification. He also discovered that alike-charged objects would repel each other and that unlike-charged objects attract. He also disproved certain misconceptions regarding electric charge, such as that of Dr. Stephen Gray who believed that electric properties of a body depended on its colour. Du Fay's observations on electricity were reported in a paper written in December 1733 and printed in Volume 38 of the Philosophical Transactions of the Royal Society in 1734. He became a member of the French Academy of Sciences in 1723. Du Fay died of smallpox in 1739.