When the vacuum cleaner is switched on, the brush rotates by a belt, and air is drawn over it by the fan to carry dirt from the carpet and into a bag suspended from the handle. Some upright cleaners have attachments for other types of vacuuming. Rug and carpet cleaners, powered by electricity, use concentrated liquid detergents added to water in a small tank. The detergents are applied to the rug and scrubbed with a brush until the lather has disappeared. When the rug is dry it is vacuumed to remove leftover dirt and detergent.
Floor polishers look like upright vacuum cleaners.
Instead of a rotating cylindrical brush, a floor polisher has from one to three disk-shaped brushes that have long, stiff bristles and spin at a high speed. The heat created by the friction of the brushes melts the wax into the floor and gives a high polish. The cylinder lawn mower, invented in 1830, changed little until after World War II, when power mowers were introduced. About the same time, the motor-powered snow remover began to replace snow shovels. Some power lawn mowers still use cylinder-mounted blades, but most have rotary blades.