Positive and negative charge

While studying static electricity, du Fay found that if you electrify two objects using different means (one by glass rod -- "vitreous", one by resin rod -- "resinous"), you can have them attract one another. He suggested two different kinds of electrical fluids.
 Charles-Francois de Cisternay du Fay France 1733 Positive and negative charge

While studying static electricity, du Fay found that if you electrify two objects using different means (one by glass rod -- "vitreous", one by resin rod -- "resinous"), you can have them attract one another. He suggested two different kinds of electrical fluids.