It is a commonplace that Britain is an island. The further truth, that it is an island which is very closely tied to the continent lying east of it, is a good deal less familiar. Geographical writers are apt, even for historical purposes, to emphasise instead those two features of the island which Mr. Mackinder in his admirable volume has called its insularity and its universality, its separation, that is, from Europe, and its central position in the world. I feel, however, that both students of ancient history, and also modern men at this particular moment, are more concerned with the peculiar relation of Britain to Europe. It is not the insularity of the island but its dependence on the continent which really matters. This dependence dates from days long before the first appearance of man; it is due, indeed, to the configuration of western Europe in remote geological periods. In those dateless days the seas which now divide our southern coast from France, and our eastern coast from the Low Countries and from Germany, were river valleys which took the drainage of a vast area extending from Wales and the Pennine hills on the north-west, to the Eifel, the Vosges and the Cevennes on the south-east. The rivers have long vanished, but their valleys, vast almost as the valley of a Missouri or a Mississippi, can still be traced in the configuration of the British and continental coasts. On each side of the sea the main rivers flow down to face each other, the main harbours of each land lie vis-à-vis and the natural entrances by which trader or soldier might wish to enter Britain open on to the main exits by which he might wish to start from the continent. Nor is it merely a matter of entrances or exits. That part of Britain which faces the continent is the lower-lying part of the great valley which I have mentioned. It is therefore fairly flat, and it offers no strategic obstacle to invaders. Its only features, its forests and its fens, are hardly large enough even to divert the march of armies and have been over-rated by writers like the late Dr. Guest and Mr. J. R. Green. The really difficult regions of Britain, the tangled uplands of Wales and west Yorkshire and the north, lie far away from the path of European aggressors. They might assist the rulers of Britain in checking an Irish invasion; they do not protect it from European influences. Britain is a land which was made to be invaded from the continent.
Nineteenth-century housing preventive conservation in Edinburgh and its Western European context