Now we have before mentioned the fact, that the rapidity of the radiation of caloric from a heated body is in proportion to the darkness of its color. This then, taken in connection with the facts just stated, readily explains the reason why the color of animals varies with the temperature. The negroes of Africa, for example, are provided with a dark complexion, in order that the great quantity of heat which the warmth of their climate causes them to absorb, may be compensated for by an increased radiation. These unfortunate people, when they come to the north, as might be supposed, suffer at first extremely from the cold. They in time, however, become somewhat inured to it. Nature provides for them by another species of adaptation, which we cannot stop minutely to describe, but which may be proved to take place. The effect of it is to increase the evolution of animal heat, and thus to make up for the excessive radiation. Natives of high latitudes, however, are white, as has been said, and consequently their limited absorption of heat is compensated for by an equally limited radiation. We see, also, from this general principle, the design of the skin being so formed as to become tanned by exposure to the sun. It is needless to dwell longer upon these facts. Taken in connection, they present perhaps one of the most interesting and harmonious arrangements that are to be met with in any of the departments of natural science. But it is by no means one of a few evidences of design, by which the advocate of religion may strengthen and confirm his faith. The whole universe is full of such examples. We have reason to believe, too, that we have but a very imperfect insight into the philosophy of Nature; that beyond the veil which separates the conquests of the human intellect from the vast tracts of knowledge, the possession of which yet remains to be acquired, there are myriads of beautifully-ordered systems, far surpassing in extent and grandeur any thing which the fancy of the wildest schemer has ever suggested to his mind. A few pebbles only have been gathered from the shore of the great ocean of truth. No wonder that the poet, impressed with this belief, should exclaim: 'There are more things in heaven and earth, Horatio, Than are dreamed of in your philosophy.' B. R. W. FOOTNOTE: [3] See 'KNICKERBOCKER,' Volume V., for an able series of articles on '_Life_,' by Dr. SAMUEL L. METCALF. TO A LOCK OF HAIR. THOU'ST played upon that cheek full oft, Thou shining tress of golden hair! And wreathed thy curl in dalliance soft Around that neck so dazzling fair: Whence hast thou caught that amber gleam, Soft as a fading autumn-sky? Part from the sun's enamoured beam, Part from that full refulgent eye.