JohnMiller3
Elite Member
- Joined
- Jan 15, 2001
- Messages
- 2,518
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- Capital District, Upstate New York
- Tractor
- Satoh S650G, MF135, MF165, JD5205
…Some interesting tidbits on time…
~~~from the web~~~
… on the night the clocks are set back, Supposing some unfortunate lady was confined with twins and one child was born 10 minutes before 1 o'clock. ... the time of birth of the two children would be reversed. ... Such an alteration might conceivably affect the property and titles in that House…
What is the origin of hours, minutes and seconds?
A sundial described in 1300 BCE reveals that the Egyptians determined a daily cycle to be made up of ten hours of daylight from sunrise to sunset, two hours of twilight and twelve hours of night. Their calendar year was divided into 36 decans, each ten days long, plus five extra days, totaling to a 365 day year. Each decan was equivalent to a third of the zodiacal sign and was represented by a decanal constellation. The night corresponded to about twelve decans, half a day to eighteen decans. Similar to the system used in Oriental clocks, the night was thus divided into twelve hours, with seasonable variations of the hour's length. Later, Hellenistic astronomers introduced equinoctial hours of equal length.
The Babylonians (in about 300-100 BCE) performed astronomical calculation in the sexagesimal (base-60) system. This was extremely convenient for simplifying time division, since 60 is divisible by 2, 3, 4, 5, 6, and 10. What we now call a minute derives from the first fractional sexagesimal place; the second fractional place is the origin of the second.
<A target="_blank" HREF=http://physics.nist.gov/GenInt/Time/ancient.html>A Walk Through Time…</A>
The main purpose of Daylight Saving Time (called "Summer Time" many places in the world) is to make better use of daylight…Daylight Saving Time also saves energy…
<A target="_blank" HREF=http://webexhibits.org/daylightsaving/c.html>History of Daylight Saving Time…</A>
<A target="_blank" HREF=http://webexhibits.org/daylightsaving/g.html>Worldwide Daylight Saving Time…</A>
History of Standard Time in the U.S.
Standard time in time zones was instituted in the U.S. and Canada by the railroads on 18 November 1883. Before then, time of day was a local matter, and most cities and towns used some form of local solar time, maintained by some well-known clock (for example, on a church steeple or in a jeweler's window). The new standard time system was not immediately embraced by all, however.
Use of standard time gradually increased because of its obvious practical advantages for communication and travel. Standard time in time zones was not established in U.S. law until the Act of March 19, 1918, sometimes called the Standard Time Act. The act also established daylight saving time, itself a contentious idea. Daylight saving time was repealed in 1919, but standard time in time zones remained in law, with the Interstate Commerce Commission (ICC) having the authority over time zone boundaries. Daylight time became a local matter. It was re-established nationally early in World War II, and was continuously observed until the end of the war. After the war its use varied among states and localities. The Uniform Time Act of 1966 provided standardization in the dates of beginning and end of daylight time in the U.S. but allowed for local exemptions from its observance. The act also continued the authority of the ICC over time zone boundaries. In subsequent years, Congress transferred the authority over time zones to the U.S. Department of Transportation (DOT), modifed (several times) the beginning date of daylight time, and renamed the three westernmost time zones.
Time zone boundaries have changed greatly since their original introduction and changes still occasionally occur. DOT issues press releases when these changes are made. Generally, time zone boundaries have tended to shift westward. Places on the eastern edge of a time zone can effectively move sunset an hour later (by the clock) by shifting to the time zone immediately to their east. If they do so, the boundary of that zone is locally shifted to the west; the accumulation of such changes results in the long-term westward trend. The process is not inexorable, however, since the late sunrises experienced by such places during the winter may be regarded as too undersirable. Furthermore, under the law, the principal standard for deciding on a time zone change is the "convenience of commerce." Proposed time zone changes have been both approved and rejected based on this criterion, although most such proposals have been accepted.
<A target="_blank" HREF=http://nist.time.gov/>Official US Time…</A>
<A target="_blank" HREF=http://www.bldrdoc.gov/timefreq/service/its.htm> Set Your Computer Clock Via the Internet…</A>
~~~from the web~~~
… on the night the clocks are set back, Supposing some unfortunate lady was confined with twins and one child was born 10 minutes before 1 o'clock. ... the time of birth of the two children would be reversed. ... Such an alteration might conceivably affect the property and titles in that House…
What is the origin of hours, minutes and seconds?
A sundial described in 1300 BCE reveals that the Egyptians determined a daily cycle to be made up of ten hours of daylight from sunrise to sunset, two hours of twilight and twelve hours of night. Their calendar year was divided into 36 decans, each ten days long, plus five extra days, totaling to a 365 day year. Each decan was equivalent to a third of the zodiacal sign and was represented by a decanal constellation. The night corresponded to about twelve decans, half a day to eighteen decans. Similar to the system used in Oriental clocks, the night was thus divided into twelve hours, with seasonable variations of the hour's length. Later, Hellenistic astronomers introduced equinoctial hours of equal length.
The Babylonians (in about 300-100 BCE) performed astronomical calculation in the sexagesimal (base-60) system. This was extremely convenient for simplifying time division, since 60 is divisible by 2, 3, 4, 5, 6, and 10. What we now call a minute derives from the first fractional sexagesimal place; the second fractional place is the origin of the second.
<A target="_blank" HREF=http://physics.nist.gov/GenInt/Time/ancient.html>A Walk Through Time…</A>
The main purpose of Daylight Saving Time (called "Summer Time" many places in the world) is to make better use of daylight…Daylight Saving Time also saves energy…
<A target="_blank" HREF=http://webexhibits.org/daylightsaving/c.html>History of Daylight Saving Time…</A>
<A target="_blank" HREF=http://webexhibits.org/daylightsaving/g.html>Worldwide Daylight Saving Time…</A>
History of Standard Time in the U.S.
Standard time in time zones was instituted in the U.S. and Canada by the railroads on 18 November 1883. Before then, time of day was a local matter, and most cities and towns used some form of local solar time, maintained by some well-known clock (for example, on a church steeple or in a jeweler's window). The new standard time system was not immediately embraced by all, however.
Use of standard time gradually increased because of its obvious practical advantages for communication and travel. Standard time in time zones was not established in U.S. law until the Act of March 19, 1918, sometimes called the Standard Time Act. The act also established daylight saving time, itself a contentious idea. Daylight saving time was repealed in 1919, but standard time in time zones remained in law, with the Interstate Commerce Commission (ICC) having the authority over time zone boundaries. Daylight time became a local matter. It was re-established nationally early in World War II, and was continuously observed until the end of the war. After the war its use varied among states and localities. The Uniform Time Act of 1966 provided standardization in the dates of beginning and end of daylight time in the U.S. but allowed for local exemptions from its observance. The act also continued the authority of the ICC over time zone boundaries. In subsequent years, Congress transferred the authority over time zones to the U.S. Department of Transportation (DOT), modifed (several times) the beginning date of daylight time, and renamed the three westernmost time zones.
Time zone boundaries have changed greatly since their original introduction and changes still occasionally occur. DOT issues press releases when these changes are made. Generally, time zone boundaries have tended to shift westward. Places on the eastern edge of a time zone can effectively move sunset an hour later (by the clock) by shifting to the time zone immediately to their east. If they do so, the boundary of that zone is locally shifted to the west; the accumulation of such changes results in the long-term westward trend. The process is not inexorable, however, since the late sunrises experienced by such places during the winter may be regarded as too undersirable. Furthermore, under the law, the principal standard for deciding on a time zone change is the "convenience of commerce." Proposed time zone changes have been both approved and rejected based on this criterion, although most such proposals have been accepted.
<A target="_blank" HREF=http://nist.time.gov/>Official US Time…</A>
<A target="_blank" HREF=http://www.bldrdoc.gov/timefreq/service/its.htm> Set Your Computer Clock Via the Internet…</A>