A further improvement now takes place. The point is armed with some material harder than wood, which material may be bone, horn, stone, metal, or other similar substance. Some nations arm the heads of their spears with sharp flakes of flint or obsidian. Some tip them with the end of a sharp horn, or even with the claws of a mammal or a bird--the kangaroo, emu, and cassowary being used for this singular purpose. In many parts of the earth, the favorite spears are armed with the teeth of sharks, while others are headed with the tail spine of the sting-ray, which not only penetrates deeply, but breaks into the wound, and always causes death. These additions to the spears, together with others formed of certain marine shells, are necessarily the productions of tribes that inhabit certain islands in the warmer seas. The last and greatest improvement that is made in the manufacture of spears is the abolition of all additions to the head, and making the head itself of metal. For this purpose iron is generally used, partly because it takes a sharp edge, and partly because it can be easily forged into any required shape. The natives of Southern Africa are wonderful proficients in forging iron, and indeed a decided capability for the blacksmith’s art seems to be inherent in the natives of Africa, from north to south and from east to west. None of the tribes can do very much with the iron, but the little which they require is worked in perfection. As is the case with all uncivilized beings, the whole treasures of the art are lavished on their weapons; and so if we wish to see what an African savage can do with iron, we must look at his spears, knives, and arrows--the latter indeed being but spears in miniature.