Charles François de Cisternay du Fay (Paris, September 14, 1698 – 1739) was a French chemist and superintendent of the Jardin du Roi. September 14 is the 257th day of the year in the Gregorian calendar (258th in leap years). ... Events January 4 - Palace of Whitehall in London is destroyed by fire. ... // About the number 1739 1739 is the smallest integer that can be written as sum of three perfect cubes, in two ways. ... Chemist Julie Perkins of Lawrence Livermore National Laboratory pours from a Florence flask. ... The Jardin des Plantes is the main botanical garden in France. ...

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He discovered the existence of two types of electricity and named them "vitreous" and "resinous" (later known as 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 of 1733 and printed in Volume 38 of the Philosophical Transactions of the Royal Society in 1734. Lightning strikes during a night-time thunderstorm. ... Vitreous refers to a material in a glassy state. ... Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interactions. ... In science and engineering, conductors are materials that contain movable charges of electricity. ... Insulators are materials which prevent the flow of heat (thermal insulators) or electric charge (electrical insulators). ... In the late-18th century, scientists developed sensitive instruments for detecting electrification, otherwise known as electrostatic charge imbalance. ... Stephen Gray (December, 1666 - February 7, 1736) was an English dyer and amateur astronomer, who was the first to systematically experiment with electrical conduction, rather than simple generation of static charges and investigations of the static phenomena. ...

External links

• Two Kinds of Electrical Fluid: Vitreous and Resinous, du Fay 1733