The Cosmic Game

Cosmic Game © Douglass A. White, 2012 v151207 76
Bishop John Wilkins
Christopher Wren
A rival proposal presented by a group of French scientists was to create a "meridian
meter" to be defined as one ten-millionth of the length of an Earth meridian along a
quadrant. A quadrant of the meridian would be the distance from the equator to the
North Pole. Although the meridian meter proposal eventually won out at that time as the
basis for the standard meter, an ordinary person in daily life is not able to derive an
accurate meter by calculating the polar circumference of the earth, taking into account the
globe's rotational oblateness, and then figuring a tiny fraction of a quadrant of the
meridian great circle as a meter. In addition, it turned out that the calculations of the
meridian meter done by the eminent French scientists were slightly off from the fraction
of the earth's meridian that they intended to use as a standard, but nevertheless a standard
metal bar was made to represent this arbitrarily selected spatial interval.
The seconds pendulum, on the other hand, is a very natural candidate for a measuring
stick that any person in any era can easily derive -- and it seems highly probable that the
Egyptians knew about it, since we have seen examples of ancient Egyptian plumb bobs
and evidence in Egyptian art of using the meter as a unit of length. To make a seconds
pendulum simply involves tying a small weight to the end of a string and then suspending
it from the string. Stand very quietly and let the weight swing back and forth at the end
of the string in a natural pendulum motion. Adjust the length of the string until the
weight swings back and forth at the speed of your heartbeat for each half-period of the
swing. The length of string from where you hold it to the weight will be 1 meter. Not
only that, the half period will be very close to one second. Thus the meter and the
second are natural units for man on this planet. (See Wikipedia, "Metre" article)
We know the ancient Egyptians used plumb bobs as a common tool in construction, and
examples of them survive in museums. They called the plumb bob device a "khekh",
and it was used as a leveler and of course to make walls plumb. Anyone using a plumb
bob becomes aware that a plumb bob is also a pendulum. Since a restful heartbeat is a
good representative of the second, the meter represents the length of the cord suspending
an oscillating plumb bob such that its half-period swing matches the human heartbeat in a
normal restful state.