Mr. Clos-Arceduc , engineer as a geographer head of the I.G.N. (National Geographic Institute) approached the problem by very an other method : it is while seeking to answer the question: " a national road having with the compartmental neighbor of the relations implying his seniority, could one find a second criterion making it possible to affirm that it covers a Roman way? ". "The remark, during a walk, that four points of "Le chemin de Saint Mathurin" marked in a characteristic way (bushes, cross, crossroads) were equidistant, gave body to the idea to use such coincidences ".

The experimental checks followed and Clos-Arceduc discovered on maps the presence of metric of 2222m, followed, on other routes by a metric news, approximately 2415 m , this time. " the assumption of a path former to the conquest , as remainder the Celtic cities that it connects,built-in or only connected to the road network of the conquerors, is very probable ". Essence was known as!

In the foreword of the work of D. Jalmain (Bib.) it writes " But, that does one note? That the Romans in Gaule used three systems of measurement: the Roman mile, one league of 2222 meters, is one thousand and half mile, which perhaps goes up with a Greek measurement, and a Gallic mile of 2420 meters approximately, obviously former on their arrival, perhaps the grandmother of the great royal league. Each time the administration Roman, more flexible and more realistic than one believes it, was in front of an established structure, anchored in the customs, it was seen obliged to respect it or compromise. " Chevallier practically thus describes the genesis of the romanized " league ".