Having surveyed some 300 stone circles in Britain and Ireland over the past 50 years, and after careful study of the placing of orthostats on the perimeters, it would seem that the stones of virtually all stone circles appear to be rationally distributed.

That is to say, although the stones might appear to be unsystematically positioned, when the angles formed by the gaps are measured from the centre of the circle they all appear to be multiples of a common number of degrees suggesting that the gaps were, in fact, measured using a common unit.

The curious thing is that the likely length of such a common unit can be logically deduced, and it happens to be related to the Megalithic Yard by a factor of pi (that is, MY x pi = 2.6m = 8 circumferential units). Thus, it is possible that a circumferential unit has caused the Megalithic Yard to be introduced into stone circle diameters.

I’ve uploaded a summary of the thesis to academia.edu (extracted from a book on the subject), but also to a series of web pages at:

http://www.gjbath.com/SCDM2/MY00.htm

I’d be interested to know if anyone has surveyed a stone circle and is thus able to check this out independently.