Electrical appliances. Historical artwork of several 19th-century household electrical appliances. The appliances are a kettle (upper left), a hot water jug (upper right), a hot plate (lower left), and an electric cooker (lower right). Electrical wires provide the electrical power for all the appliances. The principles of electricity were discovered and studied in the 18th and 19th century, and by the end of the 19th century electrical engineers were applying these principles to the design of electrical appliances. All these devices rely on electrical heating elements to boil water and cook food. Artwork from A Travers l'Electricite (G. Dary, Paris, 1900).