In our most trivial walks, we are constantly, though unconsciously, steering like pilots by certain well-known beacons and headlands, and if we go beyond our usual course we still carry in our minds the bearing of some neighboring cape; and not till we are completely lost, or turned round,--for a man needs only to be turned round once with his eyes shut in this world to be lost,--do we appreciate the vastness and strangeness of nature.