The inhabitants of great cities have recourse to gymnastics as a substitute for the sports of the country. These exercises have one advantage--they can be directed scientifically so as to strengthen the limbs that need development; but no city gymnasium can offer the invigorating breezes of the mountain. We require not only exercise but exposure--daily exposure to the health-giving inclemencies of the weather. The postman who brings my letters walks eight thousand miles a year, and enjoys the most perfect regularity of health. There are operatives in factories who go through quite as much bodily exertion, but they have not his fine condition. He is as merry as a lark, and announces himself every morning like a bearer of joyful tidings. What the postman does from necessity an old gentleman did as regularly, though more moderately, for the preservation of his health and faculties. He went out every day; and as he never consulted the weather, so he never had to consult the physicians. Nothing in the habits of Wordsworth--that model of excellent habits--can be better as an example to men of letters than his love of pedestrian excursions. Wherever he happened to be, he explored the whole neighborhood on foot, looking into every nook and cranny of it; and not merely the immediate neighborhood, but extended tracts of country; and in this way he met with much of his best material. Scott was both a pedestrian and an equestrian traveller, having often, as he tells us, walked thirty miles or ridden a hundred in those rich and beautiful districts which afterwards proved to him such a mine of literary wealth. Goethe took a wild delight in all sorts of physical exercise--swimming in the Ilm by moonlight, skating with the merry little Weimar court on the Schwansee, riding about the country on horseback, and becoming at times quite outrageous in the rich exuberance of his energy. Alexander Humboldt was delicate in his youth, but the longing for great enterprises made him dread the hindrances of physical insufficiency, so he accustomed his body to exercise and fatigue, and prepared himself for those wonderful explorations which opened his great career. Here are intellectual lives which were forwarded in their special aims by habits of physical exercise; and, in an earlier age, have we not also the example of the greatest intellect of a great epoch, the astonishing Leonardo da Vinci, who took such a delight in horsemanship that although, as Vasari tells us, poverty visited him often, he never could sell his horses or dismiss his grooms?