Every race on the face of the earth has been the subject of these speculations, and it is impossible even to suggest an outline of the subject. But if we take the European race alone, its history, or rather its prehistory, has undergone many retrospective revolutions in the short period of my own lifetime. It used to be called the Caucasian race; and I read in childhood an account of its collision with the Mongolian race; it was written by Bret Harte and opened with the query, ‘Or is the Caucasian played out?’ Apparently the Caucasian was played out, for in a very short time he had been turned into the Indo-European man; sometimes, I regret to say, proudly presented as the Indo-Germanic man. It seems that the Hindu and the German have similar words for mother or father; there were other similarities between Sanskrit and various Western tongues; and with that all superficial differences between a Hindu and a German seemed suddenly to disappear. Generally this composite person was more conveniently described as the Aryan, and the really important point was that he had marched westward out of those high lands of India where fragments of his language could still be found. When I read this as a child, I had the fancy that after all the Aryan need not have marched westward and left his language behind him; he might also have marched eastward and taken his language with him. If I were to read it now, I should content myself with confessing my ignorance of the whole matter. But as a matter of fact I have great difficulty in reading it now, because it is not being written now. It looks as if the Aryan is also played out. Anyhow he has not merely changed his name but changed his address; his starting-place and his route of travel. One new theory maintains that our race did not come to its present home from the East but from the South. Some say the Europeans did not come from Asia but from Africa. Some have even had the wild idea that the Europeans came from Europe; or rather that they never left it. Then there is a certain amount of evidence of a more or less prehistoric pressure from the North, such as that which seems to have brought the Greeks to inherit the Cretan culture and so often brought the Gauls over the hills into the fields of Italy. But I merely mention this example of European ethnology to point out that the learned have pretty well boxed the compass by this time; and that I, who am not one of the learned, cannot pretend for a moment to decide where such doctors disagree. But I can use my own common sense, and I sometimes fancy that theirs is a little rusty from want of use. The first act of common sense is to recognise the difference between a cloud and a mountain. And I will affirm that nobody knows any of these things, in the sense that we all know of the existence of the Pyramids of Egypt.