Notes on the Furness formula

The Furness formula was devised by Peter Furness in 1965 for use in ley-hunting. It attempts to predict the number of alignments of ancient sites that might be expected to occur on a map by pure chance. The publication on this website of Bob Forrest’s essay The Linear Dream, in which the Furness formula is applied to several published leys, led to re-examination of the formula.

Peter Furness’s article in The Ley Hunter is republished here, together with Donald Menzel’s article on alignments of UFO sightings (on which the formula is clearly based) and a critical discussion.

Donald H. Menzel, “Orthoteny – a lost cause: Part 2” (1965; abridged)
Peter Furness, “Are leys due to chance?” (1965)
Michael Behrend, “Notes on the Furness formula” (2014)