Breguet: Pocket Watch

Mechanical watches did not generally keep time as well as clocks because they were subject to constant movement and, unless their balance was perfectly poised, their performance varied when they were held in different positions. To eliminate such a problem, Abraham-Louis Breguet mounted the escapement and balance on a small carriage that averaged out the errors by rotating at regular intervals. Invented in 1795, this new device was called a tourbillon (literally, whirlwind) because of its revolving motion.