When we carefully trace the operation of this principle in common life, it appears that, in fact, the greater portion of our physical comforts depends upon it. "Experience" is but another name for it. We find some substances warmer, softer, harder, or more workable than others, and we apply this knowledge by substituting one for another. The savage finds the wigwam more convenient, or more easily come at, than a cave or a crevice in a rock, and he builds a wigwam;--he finds a hut more durable than a wigwam, and he substitutes a hut;--he at last finds a cottage still more convenient, and he advances in his desires and his abilities by his former experience, and he builds one.--In every advance, however, it is the application of his previous knowledge that increases his comforts, and tends to perpetuate them; and accordingly, as a proper and a general application of the "moral sense," leads directly to national _virtue_; so the proper and general application of this principle of "common sense" goes to promote every kind of personal and family _comfort_, as well as national _prosperity_. Its ramifications pierce through every design and action of industry and genius. It is the exercise of this principle alone which, in the worldly sense, distinguishes the wise man from the fool; and which gives all the superiority which is possessed by a civilized, over a savage community. It is the chief guardian of our safety, and the parent of every personal and domestic comfort. It is, in short, familiarity with its exercise that imparts confidence to the philosopher, decision to the legislator, dexterity to the artificer, and perfection to the artist. In each case it is the accumulation of knowledge _put to use_, which makes the distinction between one man and another; and it is by the aggregation of such men that a nation becomes prosperous. It must never therefore be forgotten, that it is not the possession of knowledge, but the use which we make of it, that confers distinction. For no truism is more incontrovertible than this, that knowledge which we cannot or do not use, is really useless. There is no wonder then that Nature should be at some pains in training her pupils to an exercise on which so much of their happiness and safety depends; and it is of corresponding importance, that we should investigate the means, and the mode by which she usually accomplishes her end. If we can successfully attain this knowledge, we may be enabled to pursue a similar course in the training of the young, and with decided advantage.