“As the principal arm of the ancients was the sword or the pike, their habitual formation was in deep order. The legion and the phalanx, in whatever situation they were attacked, either in front, or in right flank, or in left flank, faced everywhere without disadvantage; they could encamp on surfaces of small extent, in order to have less labour in fortifying the line of circuit, and in order to hold their ground with the smallest detachment possible. The principal arm of the moderns is the projectile; their habitual order has naturally been narrow order, the only one which permits them to bring all their projectiles to bear. “A consular army enclosed in its camp, attacked by a modern army of equal force, would be driven out of it without assault, and without being able to use their swords; it would not be necessary to fill up the fosses or to scale the ramparts: surrounded on all sides by the attacking army, pierced through, enveloped, and raked by the fire, the camp would be the common drain of all the shots, of all the balls, of all the bullets: fire, devastation, and death would open the gates and throw down the retrenchments. A modern army, placed in a Roman camp, would at first, no doubt, make use of all its artillery; but, though equal to the artillery of the besieger, it would be taken in _rouage_ and quickly reduced to silence; a part only of the infantry could use their muskets, but it would fire upon a line less extended, and would be far from producing an effect equal to the injury it would receive. The fire from the centre to the circumference is null; that from the circumference to the centre is irresistible. All these considerations have decided modern generals in renouncing the system of retrenched camps, to adopt instead natural positions well chosen. “A Roman camp was placed independently of localities: all these were good for armies whose strength consisted in arms used with the hand; it required neither experienced eye nor military genius to encamp well; whereas the choice of positions, the manner of occupying them and placing the different arms, by taking advantage of the circumstances of the ground, is an art which forms part of the genius of the modern captain. “If it were said now-a-days to a general, You shall have, like Cicero, under your orders, 5,000 men, sixteen pieces of cannon, 5,000 pioneers’ tools, 5,000 sacks of earth; you shall be within reach of a forest, on ordinary ground; in fifteen days you shall be attacked by an army of 60,000 men, having 120 pieces of cannon; you shall not be succoured till eighty or ninety-six hours after having been attacked. What are the works, what are the plans, what are the profiles, which art prescribes? Has the art of the engineer secrets which can solve this problem?”[447] CHAPTER IX. (Year of Rome 701.) (BOOK VI. OF THE “COMMENTARIES.”) CAMPAIGN AGAINST THE NERVII AND THE TREVIRI--SECOND PASSAGE OF THE RHINE--WAR AGAINST AMBIORIX AND THE TREVIRI.