"Napoleon has told us," says Colonel Hart, "that the whole art of war--the secret of success--consists in being strongest at the decisive point." Even when making a great flank or turning movement against his enemy, Napoleon kept this principle constantly in view. Thus, in these operations, though at the outset the several columns under his immediate command, numbering nearly sixty thousand men, entered Italy from different directions, separated by intervening obstacles and great distances, yet, by deceiving his adversary and by skilful manoeuvres, he succeeded in conducting fifty-five thousand men into such positions that they could, in an emergency, support one another on a single battle-field. His theory of war was concentration. His constant endeavor was to outnumber the enemy in battle. In order to accomplish this result, he nearly always made a great effort to call in his detachments just previous to a general engagement. His skill in strategy consisted in so directing his columns that when needed they could be quickly assembled on the battle-field. His skill in war consisted in the fact that he nearly always brought greater numbers against his enemy on the day of battle, even when he was outnumbered within the theatre of operations. On the battle-field, too, when it was impossible to outnumber his adversary, his quick eye discerned the vital point, the key of the position, so to speak; and there, neglecting the less important points, he massed his troops and overwhelmed his enemy. But in this campaign, strange to relate, after the battle of Montebello, and prior to the battle of Marengo, he seemed to neglect the principle of calling in his columns. When he assembled his forces south of the Po in the Stradella Pass, he felt certain that Melas would shortly advance eastward from Alessandria to attack him; yet he issued no orders for his forces north of the Po to join him. Again: at Marengo he was outnumbered, while ten thousand French soldiers along the Ticino, but a short distance away, had not a single Austrian in their front.