Orators who hold their audience spellbound. The word came into use in America in the presidential election of 1888.
“The Hon, Daniel Dougherty says: `The proudest day of his life was when he beheld his name among the ‘spell-binders’ who held the audience in rapture with their eloquence.' ” —Liberty Review July 7th, 1894, p. 13.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894