"The discovery of bronze, and the knowledge of how to make it, may, as a mere intellectual effort, be regarded as rather above than below the effort which is involved in the discovery and use of iron. As regards bronze, there is first the discovery of copper, and the way of getting it from its ore; then the discovery of tin, and the way to get it from its ore; and then the further discovery that, by an admixture of tin with copper in proper proportions, an alloy with the qualities of a hard metal can be produced. It is surely no mistake to say that there goes quite as much thinking to this as to the getting of iron from its ore, and the conversion of that iron into steel. There is a considerable leap from stone to bronze, but the leap from bronze to iron is comparatively small.... It seems highly improbable, if not altogether absurd, that the human mind, at some particular stage of its development, should here, there, and everywhere--independently, and as the result of reaching that stage--discover that an alloy of copper and tin yields a hard metal useful in the manufacture of tools and weapons. There is nothing analogous to such an occurrence in the known history of human progress. It is infinitely more probable that bronze was discovered in one or more centres by one or more men, and that its first use was solely in such centre or centres. That the invention should then be perfected, and its various applications found out, and that it should thereafter spread more or less broadly over the face of the earth, is a thing easily understood." We will find the knowledge of bronze wherever the colonies of Atlantis extended, and nowhere else; and Plato tells us that the people of Atlantis possessed and used that metal. The indications are that the Bronze Age represents the coming in of a new people--a civilized people. With that era, it is believed, appears in Europe for the first time the domesticated animals--the horse, the ox, the sheep, the goat, and the hog. (Morlot, "Smithsonian Rep.," 1860, p. 311.) It was a small race, with very small hands; this is shown in the size of the sword-hilts: they are not large enough to be used by the present races of Europe. They were a race with long skulls, as contradistinguished from the round heads of the Stone Period. The drawings on the following page represent the types of the two races. SKULLS OF THE AGE OF STONE, DENMARK This people must have sent out colonies to the shores of France, Spain, Italy, Ireland, Denmark, and Norway, who bore with them the arts and implements of civilized life. They raised crops of grain, as is proved by the bronze sickles found in different parts of Europe. It is not even certain that their explorations did not reach to Iceland. Says Humboldt,