Any one who has read a great number of letters from the Peninsula must often have been struck by the marked difference between those written by young officers and those by their seniors. The older men were often despondent in times of hardship, and were generally critical of the actions of those in command; while the subalterns and younger captains seem to have been ever in high spirits, and bubbling over with youth and gaiety. There is no doubt that, as far as regimental officers were concerned, this matter of youth put an immense amount of dash into all the operations undertaken, and inspired the soldiers with courage as well as with confidence. And it is not too much to say that an army officered by a preponderance of middle-aged men would have taken twice as long to rid northern Spain of the French. The human factor in warfare is usually overlooked by the casual reader of military history; he knows the characteristics of the chief commanders in a campaign; he knows such well-worn theories as Napoleon's presence on a battlefield being equivalent to forty thousand men; but otherwise he regards battalions as composed of officers and men all turned out of the same mould--of like temperament, of like age, and of like physique. Now, if a study were made of the average ages of British regimental officers in the several campaigns of the hundred years ending 1908, it would probably be found that they varied very considerably, and it might be interesting to discover whether the ages of the officers affected the "go" of the campaign one way or the other. But, as concerns the Peninsular army, it is an undoubted fact that regimental officers were far younger than they have ever been since. As a rule, an officer was a captain within six years of joining his regiment, and, unless unfortunate, a major within another six years, while, with any luck, he obtained the command of his regiment before he was much over thirty years of age. Napier gives many instances: Lieut.-Colonel Charles Macleod, who was killed at the head of the 43rd in the breach at Badajoz, had not reached his 27th year; Lieut.-Colonel Thomas Lloyd fell leading the 94th at the battle of Nivelle, at the age of thirty; Sir William Napier himself was only twenty-nine when he finished his last campaign, and his brother, Sir George, was but a year older at the close of the Peninsular War; Sir John Colborne (Lord Seaton) considered himself a most unlucky man in not having obtained the command of a regiment until he was thirty-two; and many other cases might be cited of the youth of the senior officers of regiments. These were the men who led their battalions to victory after victory, and their subordinates were for the most part mere boys. Many fought through the Peninsular War while still in their teens, and Colborne affirmed that, when he was commanding the 66th, he was the only officer of the regiment over twenty-five years of age. We know that young Mainwaring, of the 51st,