But the earl trusted fully as much to his talents in the way of deceiving the enemy as to his power of defeating them by open force in the field. His eccentric genius appeared to revel in the mendacious statements by which he deceived and puzzled both friend and foe; and although the spreading of a certain amount of false news for the purpose of deceiving an enemy has always been considered as a legitimate means of warfare, Peterborough altogether exceeded the usual limits, and appeared to delight in inventing the most complicated falsehoods from the mere love of mischief. At times Jack was completely bewildered by his general, so rapid were the changes of plans, so changeable his purposes, so fantastic and eccentric his bearing and utterances. That his military genius was astonishing no one can for a moment question, but it was the genius rather of a knight errant than of the commander of great armies.

As a partisan leader Peterborough is without a rival in history. Whether he would have succeeded equally well as the commander of great armies he had never an opportunity of proving, but it is more than doubtful. Rapid changes of plan, shifting and uncertain movements, may lead to wonderful successes when but a small body of troops have to be set in motion, but would cause endless confusion and embarrassment with a large army, which can only move in accordance with settled plans and deliberate purpose.