<P> Analog clocks usually use a clock face which indicates time using rotating pointers called "hands" on a fixed numbered dial or dials . The standard clock face, known universally throughout the world, has a short "hour hand" which indicates the hour on a circular dial of 12 hours, making two revolutions per day, and a longer "minute hand" which indicates the minutes in the current hour on the same dial, which is also divided into 60 minutes . It may also have a "second hand" which indicates the seconds in the current minute . The only other widely used clock face today is the 24 hour analog dial, because of the use of 24 hour time in military organizations and timetables . Before the modern clock face was standardized during the Industrial Revolution, many other face designs were used throughout the years, including dials divided into 6, 8, 10, and 24 hours . During the French Revolution the French government tried to introduce a 10 - hour clock, as part of their decimal - based metric system of measurement, but it didn't catch on . An Italian 6 hour clock was developed in the 18th century, presumably to save power (a clock or watch striking 24 times uses more power). </P> <P> Another type of analog clock is the sundial, which tracks the sun continuously, registering the time by the shadow position of its gnomon . Because the sun does not adjust to daylight saving time, users must add an hour during that time . Corrections must also be made for the equation of time, and for the difference between the longitudes of the sundial and of the central meridian of the time zone that is being used (i.e. 15 degrees east of the prime meridian for each hour that the time zone is ahead of GMT). Sundials use some or part of the 24 hour analog dial . There also exist clocks which use a digital display despite having an analog mechanism--these are commonly referred to as flip clocks . Alternative systems have been proposed . For example, the "Twelv" clock indicates the current hour using one of twelve colors, and indicates the minute by showing a proportion of a circular disk, similar to a moon phase . </P> <Ul> <Li> Examples of digital clocks </Li> <Li> <P> Digital clock outside Kanazawa Station displaying the time by controlling valves on a fountain </P> </Li> <Li> <P> Basic digital clock radio </P> </Li> <Li> <P> Mobile phone display with an analog - style clock (albeit generated by a digital computer) in the middle, and a digital - style in the top right corner </P> </Li> <Li> <P> Diagram of a mechanical digital display of a flip clock </P> </Li> </Ul> <Li> Examples of digital clocks </Li>

Who invented the second hand on a clock