It would be a great mistake to picture the Aryans setting out in some vast, organized expedition such as that of the Israelites under Moses. The study of comparative grammar suggests rather that they spread outwards from their centre in a series of little rills, each one, as it flowed, either pushing the rill in front of it a stage farther on, or flowing through it and passing beyond. During the first thousand years of this process we have very little idea of the extent to which the individual groups of these ever-widening circles—the different “races” as they were now beginning to be—were in communication with one another. After a time, however, we can discern them pretty sharply divided into two streams, a north-western and a south-eastern stream. It was the main stream which flowed north-west, and it carried along with it the ancestors of the powerful races which were afterwards to be called Greeks, Italians, Slavs, Teutons, and Celts. The settlement of the Celts in Britain and the subsequent arrival first of the Teutonic Angles and Saxons and then of the Normans, the movement of the Celts westward to Wales and Ireland, and the final streaming of their Teutonic successors right through them and across the Atlantic—all these are excellent examples of the way in which the separate rills of the north-western stream have continued ever since the first central commotion to crawl and mingle and overlap like the waves of an incoming tide. Meanwhile the south-eastern stream flowed past the Himalayas down into India and Persia, where their descendants became the Brahmanic Hindoos and the Zoroastrian Persians of a later date. That all connection was lost at a very early date between these two main streams is plain from another interesting little group of words. These are common to all the members of the north-western group, but quite unknown to the south-eastern, and perhaps the most interesting is _mere_, the Old English for ‘sea’, which is still used poetically of inland waters, and in the word _mer_maid, while its Latin form ‘mare’ is equally familiar to most educated Englishmen. From the distribution of this word among the Aryan nations, together with similar equations such as _fish_ and _piscis_, we can deduce that these two groups of travellers had already separated before either of them reached the sea-board.