It is believed that, soon after the commencement of the Bronze Age, an Aryan stream of life poured over Europe from Central Asia, and finally invaded England, driving out the old inhabitants and re-stocking the country with a host of Aryan Celts, who brought with them the knowledge of bronze manufacture. The defeated natives retreated to Ireland and the west of England and Scotland, and finally gave themselves up to their conquerors, whom they in future served as slaves. Thus were annihilated the Neolithic men of Britain, and thus was the use of polished stone weapons superseded by that of bronze implements. These Celtic invaders, like their conquered predecessors, lived upon the flesh both of wild and domestic animals, as is evident from the discovery made in 1867 at Barton Mere, near Bury St. Edmunds, where bronze spear-heads were found in and around large piles and blocks of stone, together with vast quantities of the broken bones of the stag, roe, wild boar, hare, urus, horse, ox, hog, and dog, as well as fragments of pottery. Fire was produced by these men by striking a flint flake against a piece of iron pyrites, as is evident from the discovery of these articles in and around charred remains of fires; thus a great advance was made in this direction upon the habits of the older inhabitants, who had only been able to procure fire by rapidly turning a piece of wood between their two hands, the point being fixed in a hollow on another piece of wood, so that the great friction which resulted produced heat sufficient to generate flame. Following the Bronze Age was the Iron Age, during which period the historic era commenced; and thus we have not only various discoveries to prove that iron gradually supplanted bronze, but history bears witness to the same truth. The Homeric legends abound with feats performed by heroes who wielded bronze and iron weapons; and from Hesiod, who wrote nearly five hundred years before Herodotus, we learn that iron had already superseded bronze among the Greeks, and that the archæologists of his day recognised a distinct era of the past as the Age of Bronze. The probability is that the discovery of the mode of separating iron from its ore and turning it into useful articles was made in Asia, from whence it was afterwards introduced into Europe; for we find that at the very first appearance of iron in Britain and France there were iron coins and iron ornaments in regular use among the people, which articles were no doubt brought by invading tribes of oriental people. In the early or prehistoric portion of the Iron Age the practice of burying the dead at full length first became known in Britain, cremation having always been practised previously.