To the age of stone succeeded the age of bronze, and to the age of bronze succeeded that of iron. Both in our island belong to the domination of the Celts, except in so far as the age of iron may be said to have lasted through Roman, Saxon and Norman domination down to our own day. It is admitted by all that the Celtic immigrants came in two successive waves, the distinction between which may be seen to this day, or if not always seen in physical type, at least always heard in the language of their descendants. The first wave, which is generally known as the Gaelic, eventually rolled to the Highlands and islands of Scotland and to the shores of Ireland, and is represented philologically by the kindred dialects of Gaelic and Erse. The second wave, popularly known as the Cymric, overspread the whole east and centre of Britain, the Gaels being probably forced to retire before their Cymric conquerors. To this race belong the Welsh and the Bretons of France; and Cumberland and Cornwall once spoke their language. Some of our most recent authorities on British ethnology, believing the term Cymri to be of late origin and the term Gaelic to have some misleading associations, prefer to speak of Goidels and Brythons (early national names) instead of Gaels and Cymri; but the distinction between the two races and the main lines of their geographical distribution are generally accepted, and are not affected by this question of nomenclature. It is probable, then, that at some period whose date cannot yet be even approximately conjectured, and from some quarter which we may guess, but can only guess, to have been the north of Germany, a bronze-using race of warriors and hunters, ancestors of the modern Highlander and Irishman, crossed the sea and established themselves in the island of Britain, or, as it was, perhaps, then called, Albion. Later on, but how many centuries later none can say, another race, kindred but probably hostile, invaded our shores, drove the Gaels or Goidels before them, established themselves in the best parts of the southern portion of the island, and, being themselves called Brythons, gave to the whole land the name by which the Romans called it, Britannia. As we know that iron had been introduced into the country before the arrival of the Romans, we may conjecture that this second Celtic wave consisted of the wielders of weapons of iron, and that this was one cause of their victory over the Goidels. The Brythons, thus settled in the valley of the Thames and above the chalk cliffs of Sussex, were the enemies whom Cæsar encountered when he invaded Britain.