It may perhaps be convenient to introduce a fourth period when copper alone was used and our ancestors were still ignorant of the alloys necessary for the production of bronze. Hesiod speaks of a third generation of men as possessing copper only, and although it does not do to attach undue importance to isolated facts, recent discoveries in the Cevennes, in Spain, in Hungary, and elsewhere, appear to confirm the existence of an age of copper (Fig. 2). We may add that the mounds of North America contain none but copper implements and ornaments, witnesses of a time when that metal alone was known either on the shores of the Atlantic or of the Pacific29 (Fig. 3). [Illustration: 3.] Copper beads, from Connett’s Mound, Ohio (natural size). It is impossible to fix the duration of the Stone age. It began with man, it lasted for countless centuries, and we find it still prevailing amongst certain races who set their faces against all progress. The scenes sculptured upon Egyptian monuments dating from the ancient Empire represent the employment of stone weapons, and their use was continued throughout the time of the Lagidæ and even into that of the Roman domination. A few years ago, on the shores of the Nile, I saw some of the common people shave their heads with stone razors, and the Bedouins of Gournah using spears headed with pointed flints. The Ethiopians in the suite of Xerxes had none but stone weapons, and yet their civilization was several centuries older than that of the Persians. The excavations on the site of Alesia yielded many stone weapons, the glorious relics of the soldiers of Vercingetorix. At Mount Beuvray, on the site of Bibracte, flint hatchets and weapons have been discovered associated with Gallic coins. At Rome, M. de Rossi collected similar objects mixed with the _Æs rude_. Flint hatchets are mentioned in the life of St. Éloy, written by St. Owen, and the Merovingian tombs have yielded hundreds of small cut flints, the last offerings to the dead. William of Poitiers tells us that the English used stone weapons at the battle of Hastings in 1066, and the Scots led by Wallace did the same as late as 1288. Not until many centuries after the beginning of the Christian era did the Sarmatians know the use of metals; and in the fourteenth century we find a race, probably of African origin, making their hatchets, knives, and arrows of stone, and tipping their javelins with horn. The Japanese, moreover, used stone weapons and implements until the ninth and even the tenth century A.D.