Let us consider, to fix our ideas, a ground A D V, inclined at 45 degrees, in which is to be made the trench A B C D. The great wall A B C had 16 Roman feet in elevation: we will suppose that A B was inclined at 5 on 1, and that the small wall D C was 6 feet high.
The amount of rubbish removed would be as follows:—Section A B C D = 64 square feet, or, reducing it into square mètres, A B C D = 5 square mètres 60 centimètres.
The mètre in length of the earth thrown out would give thus 5·60 cubic mètres.
If we consider the facility of labour in the trench, since the earth has only to be thrown down the slope, we shall see that two men can dig three mètres in length of this trench in two days. Therefore, admitting that the 10,000 men at Cæsar’s disposal had only been employed a quarter of the time, from two to three days would have been sufficient for the execution of the complete work.
[166] De Bello Gallico, I. 8.
[167] De Bello Gallico, I. 9.—The country of the Sequani comprised the Jura, and reached to the Pas-de-l’Ecluse. (See Plate 2, Map of Gaul.)
[168] It has been considered to have been an error of Cæsar to place the Santones in the proximity of the Tolosates: modern researchers have proved that the two peoples were not more than thirty or forty leagues from each other.
[169] Several authors have stated wrongly that Cæsar went into Illyria; he informs us himself (De Bello Gallico, III. 7) that he went thither for the first time in the winter of 698.
[170] We believe, with General de Gœler, from the itinerary marked on the Peutingerian table, that the troops of Cæsar passed by Altinum (Altino), Mantua, Cremona, Laus Pompei (Lodi Vecchio), Pavia, and Turin; but, after quitting this last place, we consider that they followed the route of Fenestrella and Ocelum. Thence they directed their march across the Cottian Alps, by Cesena and Brigantium (Briançon); then, following the road indicated by the Theodosian table, which appears to have passed along the banks of the Romanche, they proceeded to Cularo (Grenoble), on the frontier of the Vocontii, by Stabatio (Chahotte or Le Monestier, Hautes-Alpes), Durotineum (Villards-d’Arenne), Melloseeum (Misoen or Bourg-d’Oysans, Isère), and Catorissium (Bourg-d’Oysans or Chaource, Isère).
[171] “Locis superioribus occupatis.” (De Bello Gallico, I. 10.)