59 (return) [ The subject of the ancient machines is treated with great knowledge and ingenuity by the Chevalier Folard, (Polybe, tom. ii. p. 233-290.) He prefers them in many respects to our modern cannon and mortars. We may observe, that the use of them in the field gradually became more prevalent, in proportion as personal valor and military skill declined with the Roman empire. When men were no longer found, their place was supplied by machines. See Vegetius, ii. 25. Arrian.] Chapter I: The Extent Of The Empire In The Age Of The Antonines.—Part III. The camp of a Roman legion presented the appearance of a fortified city. 60 As soon as the space was marked out, the pioneers carefully levelled the ground, and removed every impediment that might interrupt its perfect regularity. Its form was an exact quadrangle; and we may calculate, that a square of about seven hundred yards was sufficient for the encampment of twenty thousand Romans; though a similar number of our own troops would expose to the enemy a front of more than treble that extent. In the midst of the camp, the prætorium, or general’s quarters, rose above the others; the cavalry, the infantry, and the auxiliaries occupied their respective stations; the streets were broad and perfectly straight, and a vacant space of two hundred feet was left on all sides between the tents and the rampart. The rampart itself was usually twelve feet high, armed with a line of strong and intricate palisades, and defended by a ditch of twelve feet in depth as well as in breadth. This important labor was performed by the hands of the legionaries themselves; to whom the use of the spade and the pickaxe was no less familiar than that of the sword or _pilum_. Active valor may often be the present of nature; but such patient diligence can be the fruit only of habit and discipline. 61 60 (return) [ Vegetius finishes his second book, and the description of the legion, with the following emphatic words:—“Universa quæ in quoque belli genere necessaria esse creduntur, secum legio debet ubique portare, ut in quovis loco fixerit castra, armatam faciat civitatem.”] 61 (return) [ For the Roman Castrametation, see Polybius, l. vi. with Lipsius de Militia Romana, Joseph. de Bell. Jud. l. iii. c. 5. Vegetius, i. 21—25, iii. 9, and Memoires de Guichard, tom. i. c. 1.]