Without referring to the most sacred and ancient of authorities, we may find existing natural evidence abundantly sufficient to establish the belief of the common descent of our race. There are not in the human form differences such as distinguish separate species of the brute creation. All races of men are nearly of like stature and size, varying only by the accidents of climate and food favorable or adverse to their full development. The number, shape, and uses of limbs and extremities are alike, and internal construction is invariably the same. These are circumstances the least acted upon by situation and temperature, and therefore the surest tests of a particular species. Color is the most obvious and the principal indication of difference in the human families, and is evidently influenced to a great extent by the action of the sun,[209] as the swarthy cheek of the harvest laborer will witness. Under the equator we find the jet black of the negro; then the olive-colored Moors of the southern shores of the Mediterranean; again, the bronzed face of the Spaniard and Italian; next, the Frenchman, darker than those who dwell under the temperate skies of England; and, last, the bleached and pallid visages of the north. Along the arctic circle, indeed, a dusky tint again appears: that, however, may be fairly attributed to the scorching power of the sun, constantly over the horizon, through the brief and fiery summer. The natives remain generally in the open air during this time, fishing, or in the chase; and the effect of exposure stamps them with a complexion which even the long-continued snows can not remove. In the rigorous winter season, the people of those dreary countries pass most of their time in wretched huts or subterranean dwellings, where they heap up large fires to warm their shivering limbs. The smoke has no proper vent in these ill-constructed abodes; it fills the confined air, and tends to darken the complexions of those constantly exposed to its influence.