For some time clockmakers have attempted to show the comparative time in different parts of the world; this became really important after the invention of the electric telegraph. A clock by Thomas Lister of Halifax, Yorkshire, c. 1780, has a special dial from which the time in 24 places in the world can be calculated with reference to the main dial. Some chapter rings on 18th-century longcase clocks have the names of various foreign towns engraved on their outer edge: when the hour hand of the clock is opposite these names it is noon in the respective places. In the 19th-century large universal-time clocks, or world-time clocks as they are sometimes known, were installed in the offices of commercial organisations with worldwide interestes. These had multiple dials to show time in the principal cities of the world, the dials being set in phase with the main movement of the clock.