In the second century, Ptolemy, the Egyptian astronomer, composed the first geography of the world, illustrated by maps. He would probably get his information about Britain—which was still called Albion—from Roman officers. What is now England, is shown with fair accuracy; but north of the Wear and the Solway it is difficult to identify names, or even the prominent features of the country; and the configuration of the land stretches east and west, instead of north and south. The Celts were not indigenous to Britain. It is hardly possible to trace in any—in the very earliest peoples, of whom history or archæology can speak—the first occupants of any one spot on the earth. Science is ever pushing back, and still farther back, the era of man’s first appearance as fully developed man upon the globe. And in his families, his tribes, and his nations, man has ever been a migrant. Impelled by the necessities of life, or by his love of adventure or of conquest, he has changed his hunting and grazing grounds, made tracks through forests, sought out passes between mountains; and the great, all-encompassing sea has ever been a fascination; the sound of its waves a siren-song inciting him to make them a pathway to new lands beyond his horizon. Before the Celtic Britons dwelt in this island in the northern seas, which they have helped to a great name, there were tribes here who had not yet learned the uses of the metals, whose spear-heads and arrow-tips were flints, their axes and hammers of stone. But the Celts were of that great Aryan race, tribes of which, spreading westwards over Europe, had carried with them so much of the older civilization of Persia, that they never degenerated into savagedom. The Britons were probably in pre-Roman times the only distinctive people upon the island. How came the Celts to Britain? Probably colonies from Old Gaul first took possession of the portions of Britain nearer to their own country; and gradually spreading northwards, came in time to be scattered over what is now England and Wales, and the Lowlands of Scotland. Ireland being in sight of Britain from both Wigton and Cantyre, adventurers would cross the North Channel, and become the founders of the Irish nation.