Alexander Thom (1894-1985)
Born in Scotland in 1894, Alexander Thom was a student at Glasgow University. Later he returned there as a lecturer (1922-1939) before becoming a professor of engineering at Oxford University, a post he held from 1945 until his retirement in 1961. He died in 1985.
As early as 1934 Thom had become interested in prehistoric stone circles and their astronomical associations. The nature of his interests is expressed in an article he published in 1951 in the "Journal of the British Astronomical Association" entitled "The solar observations of megalithic man."
Thom also undertook the project of accurately surveying and carefully measuring megalithic sites throughout Britain, the initial results of which he published in 1955 in the "Journal of the Royal Statistical Society". After his retirement, he published two more articles in the same journal, in 1962 and 1964, which addressed megalithic units of length.
His discovery of what he called the "megalithic yard" (2.72 feet, or 0.83 metres), a unit of measurement he found employed consistently at many prehistoric megalithic sites, is a key feature of his book "Megalithic Sites in Britain", published in 1967, for which he had surveyed some 300 megalithic circles, alignments, and isolated standing stones. This was followed in 1971 by another book, "Megalithic Lunar Observatories".
Besides the "megalithic yard", Thom also contributed a heightened awareness of the geometry of stone circles, showing there were six types: true circles, ellipses, two sorts of egg-shaped circles, and two sorts of flattened circles.
In important ways, Thom's work converged with that of Gerald Hawkins which emphasized the preoccupation of Stonehenge's builders with astronomy and mathematics. Whereas Hawkins focused on Stonehenge, Thom was able to demonstrate that a large number of other megalithic sites were also oriented to the sun and the moon.
Although admired for his impeccable science and respected for the thoroughness and intellectual rigour of his research, Thom's findings remain controversial among scholars.
For more information on Alexander Thom click to the following:
Stonehenge & The Druids
Archaeoastronomy at Stonehenge