Psychohistorical Crisis Page 75
The Arabic or Black Cubit, which dates to a time much earlier than the Moslem conquests, divides Earth’s circumference into 81 million cubits, with 3750 to the minute of arc. At 0.49324 meters it is exactly twice the length of the one sidereal-second foot and was probably computed as the eighth part of a four sidereal-second pendulum.
The Nautical foot which divides the Earth’s circumference into 129,600,000 parts, 6000 to the minutes of arc, 100 to the second of arc, is 5/4ths of the one sidereal-second foot. When measured at the sacred latitude of 51°25’43” it is exactly 76/75ths of the English foot, the same ratio used by the British Admiralty.
The Egyptian Royal Cubit...
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