Clock

A clock (from the Latin cloca, "bell") is an instrument for measuring time. A clock is usually a physical instrument; an especially accurate one is called a chronometer. The clock in its modern form (24 hour clock) has been in use since at least the 14th century. Clock can refer to an abstract system of time measurement (see calendar for other measurements). Modern clocks define constant units of time: an hour is always sixty minutes, of sixty seconds each.

References

• Bruton, Eric. The History of Clocks and Watches. London: Black Cat, 1993.
• Edey, Winthrop. French Clocks. New York: Walker & Co., 1967.
• Lloyd, Alan H. ?Mechanical Timekeepers.? In A History of Technology. Vol. III. Edited by Charles Joseph Singer, et. al. Oxford: Clarendon Press, 1957, pp. 648-675.
• Robinson, Tom. The Longcase Clock. Suffolk, England: Antique Collector?s Club, 1981.
• Smith, Alan. The International Dictionary of Clocks. London: Chancellor Press, 1996.
• Tardy. French Clocks the World Over. Part One and Two. Translated with the assistance of Alexander Ballantyne. Paris: Tardy, 1981.
• Yoder, Joella Gerstmeyer. Unrolling Time: Christiaan Huygens and the mathematization of nature. New York: Cambridge University Press, 1988.