According to hypothesis of Alan Butler and Christopher Knight, megalithic civilization of Britain and Britanny, France used 366-degree geometry (also called megalithic geometry). This geometry, whose origin is claimed to go back to c. 3,000 BC, would have used a 366-degree circle rather than a 360-degree circle as we do today. Alan Butler also asserts that 366-degree geometry has been materialised on the Earth by what he terms Salt Lines – 366 meridians and 183 parallels crisscrossing the globe at regular intervals (the equivalents of modern-day 360 meridians and 180 parallels).
Butler and Knight claim that the Megalithic Yard is a fundamental number for the Sun, the Moon and the Earth. The Megalithic arc second as measured on the Earth equator is very close to 366 Megalithic Yards, while the lunar Megalithic arc second as measured on the Moon equator is very close to 100 Megalithic yards, and the solar Megalithic arc second as measured on the Sun equator is very close to 40,000 Megalithic Yards.
French author Sylvain Tristan suggests that the numbers 366, 40 and 10 are not only fundamental to the Earth, the Moon and the Sun, but also to the human body and water. In the water-based Celsius temperature measurement system, which is directly linked to base-10 numeration, the average human body temperature is 36.6 degrees. On a scale where the absolute zero is defined as being minus 1,000 degrees, water boils at the temperature of 366 degrees, which points at something intrinsically fundamental in these numbers.
Alan Butler also asserts that 366-degree geometry has been materialised on the Earth by what he terms Salt Lines – 366 meridians and 183 parallels crisscrossing the globe at regular intervals (the equivalents of modern-day 360 meridians and 180 parallels). Most of the world’s capital cities or sanctuaries of late prehistory and antiquity are located on the course of Salt Lines: it includes Stonehenge, Avebury, Babylon, Assur, Niniveh, Thebes, Abu Simbel, Harappa, Mycenae, Athenes, Hattusa, Alesia, Teotihuacan, Chichén Itzá, Tiwanaku and Caral. According to the author, such a situation challenges probability laws and can hardly been explained away by chance only, and thus is the result of some common knowledge held by the Megalithic civilisation that might have spread to different parts of the globe.
The Ring of Brodgar stands on a narrow neck of undulating moorland between the Lochs of Harray and Stenness. It is of special interest and importance on account of the great extent of the area enclosed, the relative perfection of the ring of monoliths, and the presence of a wide and deep ditch which completely surrounds it. The ditch measures about 30ft in breadth and is about 6ft deep.
The central area measures about 370ft in diameter. At the time of writing, the positions of at least forty are visible, and there are spaces for twenty more, if it be assumed that they were erected at approx. equal distances apart. This would bring up the total in the original plan to sixty. By 1929 only twenty-seven were still erect. Some of the stones have runic inscriptions. Also a rough stone axe, a hammer-stone of quartz, and a small stone, bearing a tree rune and a small arrowhead of reddish coloured flint was picked up in 1928 close to the N.W. traverse.