{15}
Critics say—and with some show of reason—“Look at the large number of ‘ancient sites,’ peppered all over your map. Alinements such as you get through a number of points can easily come by accidental coincidence, not proving the lines to be man-made.”
It is well to face this argument, for I have sometimes found advocates of my thesis quoting instances which either have too few mark-points for real proof, or are too careless in the accuracy of alinement.
As regards the last point, I ought to mention that before inking in the rather coarse lines on the sketch-maps, the greatest possible care was taken to see that the lines, put in first with a fine lead pencil and a long accurate straight edge, do go precisely through the mark-points on the map, with no error. To be “near,” as for instance the corner of the churchyard when taking a church as mark-point is not acceptable.
Assuming this standard of accuracy, I have marked haphazard a number of crosses with pencil on a sheet of paper to see how many alinements can be found.
Beginning with a three-point alinement, this was found to have no value as evidence of human arrangement, for an average of one such line comes when only nine marks are made on a sheet, and with a hundred mark-points there were at least as many three-point alinements as points.
But the case is quite different if a four-point alinement is looked for, only one or two instances being discoverable on a large sheet with a hundred points. It was then found that the chances of a five-point alinement are still scarcer, and this in geometric proportion, for many trial sheets can be made without finding one.
I, therefore, take five-points as my minimum standard for a fair (but not an absolute) presumption of proof. When such a map-alinement is found there almost invariably follows convincing evidence with field-survey, additional mark-stones, bits of ancient tracks, hill-notches, legends of underground passages on the line, or other items.
All my plans in this book had the ancient sites or mark-points marked in exact position as on the Ordnance maps; this was done before the lines were ruled through these points. The lines were not ruled first and the sites planted on them. All are maps (although reduced), not theoretic sketch-diagrams.