One of the secrets of happiness is to work for the sake of working, and not for the sake of a reward but for the pleasure of giving. Every thing in Nature, except men, are fulfilling this law spontaneously: rosebushes offer the beauty of their flowers to anyone passing by the road; if one is making a stroll by a stream, we find freshness, crystal water, rest, and points to reflect; trees are deliver living or dead wood for a fire that gives light, heat and will to live; birds make us happy by their flights and trills; by night, in the field, not in the city, we have stars making us think of the greatness of God.