On a brilliant day in May, in the year 1868, a gentleman was reclining at his ease on the great circular divan which at that period occupied the centre of the Salon Carre, in the Museum of the Louvre. This commodious ottoman has since been removed, to the extreme regret of all weak-kneed lovers of the fine arts, but the gentleman in question had taken serene possession of its softest spot, and, with his head thrown back and his legs outstretched, was staring at Murillo's beautiful moon-borne Madonna in profound enjoyment of his posture. He had removed his hat, and flung down beside him a little red guide-book and an opera-glass. The day was warm; he was heated with walking, and he repeatedly passed his handkerchief over his forehead, with a somewhat wearied gesture. And yet he was evidently not a man to whom fatigue was familiar; long, lean, and muscular, he suggested the sort of vigor that is commonly known as "toughness." But his exertions on this particular day had been of an unwonted sort, and he had performed great physical feats which left him less jaded than his tranquil stroll through the Louvre. He had looked out all the pictures to which an asterisk was affixed in those formidable pages of fine print in his Badeker; his attention had been strained and his eyes dazzled, and he had sat down with an aesthetic headache.