Some approaches in the branch of historic metrology are highly speculative but others are well reasoned. Some people describe all nonofficial metrology as pseudoscience, but this is frequently inappropriate. Interest in ancient metrology was triggered by research into the various Megalith building cultures and the Great Pyramid of Giza. Resistance to the replacement of Imperial units by the metric system also played a role in some writers' thinking.
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In 1637 John Greaves, professor of geometry at Gresham College, made his first of several studies in Egypt and Italy, making numerous measurements of buildings and monuments, including the Great Pyramid. These activities caused him to be deprived of his Gresham professorship for having neglected his duties, but it did fuel many centuries of interest in metrology of the ancient cultures by the likes of Sir Isaac Newton and the French Academy. [Shalev]
The first known description and practical use of a physical pendulum is by Galileo Galilei, however, Flinders Petrie, a disciple of Smyth, is of the opinion that it was used earlier by the ancient Egyptians. Writing in an article in Nature, 1933 Petrie says:
If we take the natural standard of one day divided by 10^{5}, the pendulum would be 29.157 inches at lat 30 degrees. Now this is exactly the basis of Egyptian land measures, most precisely known through the diagonal of that squared, being the Egyptian double cubit. The value for this cubit is 20.617 inches, while the best examples in stone are 20.620±0.005inches. ^{[1]}
No explanation is offered as to why no Egyptian pendulums have been found, despite the extremely rich archaeological material from this culture, nor to the question as to why none of the rich historic material from Egypt mentions this.
From the 18th century, inspired by the statement of Aristotle that the circumference of the Earth was calculated as 400,000 stadia, it became a belief among members of the French Académie des Sciences that ancient linear measures were all derived directly from the circumference of the Earth. Archaeologist Jean Antoine Letronne, in 1822, tried to show the connection to a supposed preGreek measurement of the Earth.
John Taylor, in his 1859 book "The Great Pyramid: Why Was It Built? & Who Built It?", claimed that the Great Pyramid was planned and the building supervised by the biblical Noah, and that it was:
A paper presented to the Royal Academy on the topic was rejected.
Taylor's theories were, however, the inspiration for the deeply religious archeologist Charles Piazzi Smyth to go to Egypt to study and measure the pyramid, subsequently publishing his book Our Inheritance in the Great Pyramid (1864), claiming that the measurements he obtained from the Great Pyramid of Giza indicated a unit of length, the pyramid inch, equivalent to 1.001 British inches, that could have been the standard of measurement by the pyramid's architects. From this he extrapolated a number of other measurements, including the pyramid pint, the sacred cubit, and the pyramid scale of temperature.
Smyth claimed—and presumably believed—that the inch was a Godgiven measure handed down through the centuries from the time of Israel, and that the architects of the pyramid could only have been directed by the hand of God. To support this Smyth said that, in measuring the pyramid, he found the number of inches in the perimeter of the base equalled 1000 times the number of days in a year, and found a numeric relationship between the height of the pyramid in inches to the distance from Earth to the Sun, measured in statute miles.
Smyth used this as an argument against the introduction of the metre in Britain, which he considered a product of the minds of atheistic French radicals.
By the time measurements of Mesopotamia were discovered, by doing various exercises of mathematics on the definitions of the major ancient measurement systems, various people (JeanAdolphe Decourdemanche in 1909, August Oxé in 1942) came to the conclusion that the relationship between them was well planned. Livio C. Stecchini claims in his A History of Measures:
Stecchini makes claims that imply that the Egyptian measures of length, originating from at least the 3rd millennium BC, were directly derived from the circumference of the earth with an amazing accuracy. According to "Secrets of the Great Pyramid" (p. 346 [2]), his claim is that the Egyptian measurement was equal to 40,075,000 meters, which compared to the International Spheroid of 40,076,596 meters gives an error of 0.004%. No consideration seems to be made to the question of, on purely technical and procedural grounds, how the early Egyptians, in defining their cubit, could have achieved a degree of accuracy that to our current knowledge can only be achieved with very sophisticated equipment and techniques.
Building on Stecchini and Smyth, John F. Neal, in his book All Done With Mirrors (in 2000), came to the conclusion that the foot was the grand unit, and that the common system of the ancient cultures was that the definition of their respective foot is 1/360,000th part of the longitudinal meridian degree of their respective latitudes. [3] Even the theoretical odometer described by Vitruvius was used as evidence [4]. The conclusion of Neal's book is:
This is then used as a form of defense for imperial units against the metric system, and adopted by parts of the antimetric movement.
Oxford engineering professor Alexander Thom, doing statistical analysis of survey data taken from over 250 stone circles in England and Scotland, came to the conclusion that there must have been a common unit of measure which he called a megalithic yard. This research was published in the Journal of the Royal Statistical Society (Series A (General), 1955, Vol 118 Part III p275295) as a paper entitled A Statistical Examination of the Megalithic Sites in Britain.
Later, these ideas were further developed as defence for the Imperial units against the emerging metric system, and adopted by parts of the antimetric movement. Robin Heath, in his book Sun, Moon & Stonehenge, connects the megalithic yard (and thus Stonehenge) to the imperial foot, and manages to connect a few astronomical phenomena, and the Egyptian Royal Cubit (and thus the Great Pyramid) into one grand equation (MY is an abbreviation for megalithic yard):
This seems to bring pseudoscientific metrology to new heights, especially in view of the conclusion:
Christopher Knight and Alan Butler further develop the work of Smyth's and Stecchini's "Grand Scheme" in their Civilization One hypothesis, which describes a megalithic system of units.^{[2]} This system is claimed to be the source of all standard units used by civilization, and is so named after the Neolithic builders of megaliths. Knight contends the reconstructed megalithic yard (0.8297 m) is evidence of the megalithic system. Although the megalithic yard is the work of Alexander Thom, Knight makes a novel contribution by speculating on how the MY may have been created by using a pendulum calibrated by observing Venus. The idea of using Venus as a celestial clock addresses one of the main critiques of Thom's work; that no megalithic measuring rods have ever been found. It also explains the uniformity of the MY across large geographical areas.
The division time and angle are closely connected in positional astronomy. The 366.25 sidereal days in a equinox year are rounded off to 366 days in a year or 366 megalithic degrees in a circle. Each of these degrees is subdivided into 60 minutes and 6 seconds. The convention of is present in Minoan Civilization. The ratio of 366°:60′:6″ is used to construct the entire megalithic system.
Knight outlines a procedure for Neolithic astronomers to make a Venus Pendulum.
Mathematically a megalithic degree is ^{1}⁄_{366} part of a Venusian day, which is the time for Venus to trace one complete circle across the sky. At maximum retrograde Venus is moving slower than the background stars so a Venusian day is slightly longer than a sidereal day and a megalithic degree of the Venusian day lasts 236.2486 s. Into this measure of time, 366 beats of 0.5 MY Venus pendulum fit very precisely. Venus's retrograde motion was determined by Neolithic astronomers in Megalithic observatories such as Newgrange in Ireland, which uses three interlocking carved spirals to perform astronomical calculations by geometric methods. Anecdotally, a number of small weights are present at all Megalithic sites which may be discarded pendulum bobs.
The MY was designed as a geodectic unit related to the polar circumference of Earth. 1 megalithic second of Earth's polar circumference is 366 MY. This relationship suggests a precise knowledge of Earth's dimensions.^{[2]}
Measures of volume and mass are derived from the Venus pendulum. It is divided by custom into 20 megalithic inches. The 1:20 ratio is a common system of subdivision across cultures based on parts of the human body. A cube with a side of 4 megalithic inches has a volume equal to one imperial pint with a 0.51% error.^{[2]} When the megalithic pintcube is filled with grain its weight is one imperial pound. A number of these pintcubes have been found carved into the rock at Skara Brae in Orkney Scotland. Some of the archaic measurements from the British Isles show a planned order when expressed in terms of megalithic units. For example the familiar imperial acre is 24 MY × 240 MY and the obscure square rod is 6 MY × 6 MY.^{[2]}
Elements of the megalithic system are present in Minoan civilization. The Phasistos Disc is a computing aid that uses 366 glyphs to calculate Venus's orbital period. The Minoan foot (0.3036 m) is also a geodectic unit when combined with the megalithic degree such that one megalithic second is 1000 Minoan feet.^{[2]}
