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Manís Natural Timepiece
From the first crude sundials that divided the days into vague and irregular intervals, to the finest navigational chronometers that maintain split-second accuracy over long periods, our basic source of time has always been the rotation of the earth we live on and the apparent motion of the sun that this rotation causes. Even before any concept of time existed, the daily alternation of light and darkness must have regulated manís activities, as it does the activities of animals today. As recently as one hundred thirty years ago, every city, town and hamlet on earth observed its own local time based on the instant that the sun reached its zenith at that locality, and "high noon" was the universal time for setting clocks and watches.
The Time Zone Problem
Those simple and straightforward days of Local Sun Time ended when the first transcontinental railroads ushered in the era of modern long-distance transportation. The time confusion for travellers and trainmen became so great on long trips that in the 1870s the 24 "standard" world time zones we know today were set up by international agreement. These zones solved one problem but created another. Today, in our age of high speed jet ravel, electronic communications, and growing international involvement, more and more people need to know, or are interested in knowing, what time it is somewhere else ó often halfway around the earth. The problem that time zones created is that the ordinary clock and watch are highly inadequate for telling time on a global basis.
The Inadequacy Of The Clock
Conventional clocks are essentially local time indicators and no more. (The last basic innovation in the design of clocks ó outside of improved accuracy and minor gimmickry ó was back in the 17th century when someone added the minute hand to the theretofore single-handed clock dial.) Because clocks and watches present time as an abstract (and sometimes meaningless) number, learning the time in another part of the world is a matter of working with other abstract numbers (time zone conversion factors) as well as figuring out whether it is A.M. or P.M., what day of the week and what date it is. Since there are at least 34 local world time zones (24 standard and 10 nonstandard) the problem is not simple. And, for this same reason, the idea of multiple dials or clocks for keeping track of world time is impractical.
Geochron: The New World Timepiece

Geochron solves all these problems in one stroke by combining the answers to the two questions "What time?" and "Where?" in a single easy-to-read graphic analog. Physically, Geochron looks like a framed world map, about 3 by 2 feet in size. It is designed to be hung on the wall. The colorful map itself, a precision Mercator projection printed on dimensionally stable Mylar, is an endless belt that is driven slowly from left to right by an electric clock motor in synchronization with the rotation of the earth. All known legal time zone boundaries are delineated on the map which, in most cases, converge on lettered pointers on the top edge of the map. These letters identify the standard time zones and also represent the short-wave radio prefix for that zone.

Specifically, the Geochron displays the following:

  • Legal Zone Time
  • Greenwich Mean and Apparent Times
  • Local Apparent Time
  • Moments of Sunrise and Sunset
  • Duration of Daylight
  • Sun's Meridian Passage
  • Sun's Equation of Time
  • Degrees of Latitude and Longitude
  • The Geographic Extent of the Prevailing Day and Date
Reading World Time On Geochron
The time zone arrows point to a stationary time scale across the top of the map that reads from midnight to the left, through noon in the middle, to midnight again at the right. To read the time in any standard zone in the world, you simply find that place on the map and follow the zone boundaries to the arrow which points out the correct time. Certain nonstandard and pocketed zones have boundaries that do not extend to an arrow. These are marked with a letter and a number. The letter tells you which arrow to read and the number shows the deviation from standard time. In the case of India, for example, the designation is E + 30. This means that you add 30 minutes to time you read on the E pointer. Simple addition of a fraction of an hour in the case of the 10 nonstandard zones is the only calculation ever required in reading the Geochron.
Reading The Date And Day Of The Week On Geochron 
Since the map is moving slowly across the frame from left to right, the International Dateline crosses the frame once each day. The days of the week observed on either side of the Dateline are displayed in windows near the bottom of the map. The date and month for these two days are likewise shown on an indicator mounted at the bottom of the Geochron.
Geochron: Graphic Analog Of Day And Night 
Perhaps the most fascinating thing about Geochron is that it shows the exact portions of the earth that are in daylight, and those that are in darkness, at the moment you are observing Geochron. The brightly illuminated pattern in the center of the map delineates those areas that are in daylight. The left edge of this pattern is the line of sunrise as it sweeps across the earth, and the right edge is the line of sunset. Because the length of the day changes daily as the earth progresses through its seasons, the light pattern on Geochron changes also, almost imperceptibly, from day to day. Thus, with Geochron you can read the time of sunrise and sunset and the relative length of day and night for any latitude. Because Geochron is a graphic analog, the viewer soon gains an instinctive appreciation of what time it is everywhere and it no longer becomes necessary to read an abstract number to know if it is an appropriate time to call someone in Paris, France, or Sydney, Australia. A glance at the light pattern on the map instantly tells you whether it is daylight at those places or the middle of the night. This illuminated pattern also shows the progress of the seasons during the year. Such heretofore abstract phenomena as the summer and winter solstices and the vernal and autumnal equinoxes are clearly and graphically shown by the Geochron light pattern.
Other Uses For Geochron
Geochron has two simple controls that allow it to be used for far more than just telling time. One knob at the base of the unit allows the map to move the map horizontally across the frame. It is used to set the correct time on the Geochron scale when it is first plugged in. But, by moving the map, you can also determine the time of sunrise and sunset at any locality on that day and see the relative effect of latitude on these times. The second knob at the base of the unit allows you to set the date indicator to any day of any month in the year. Since the light pattern mechanism is coupled to the date indicator, this also changes and shows the light condition on earth at that time of year. This feature has been found valuable by educators, motion picture producers, military men, as well as by the average person who just wants some help in planning his vacation. Geochron also shows the exact zenith position of the sun at any time on any date and graphically indicates the relationship between Apparent Solar Time and Mean Solar Time as expressed in the Equation of time. This is indicated by a small black dot that follows the zenith position of the sun as it traverses the earth.
About Time & the Geochron
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The Savvy Traveller
Chicago, Illinois
Telephone: 773/525-9300