Page "Electric charge" Paragraph 19

One of the foremost experts on electricity in the 18th century was Benjamin Franklin, who argued in favour of a one-fluid theory of electricity.

Franklin imagined electricity as being a type of invisible fluid present in all matter ; for example, he believed that it was the glass in a Leyden jar that held the accumulated charge.

He posited that rubbing insulating surfaces together caused this fluid to change location, and that a flow of this fluid constitutes an electric current.

He also posited that when matter contained too little of the fluid it was " negatively " charged, and when it had an excess it was " positively " charged.

For a reason that was not recorded, he identified the term " positive " with vitreous electricity and " negative " with resinous electricity.

William Watson arrived at the same explanation at about the same time.