While the primitive Aryan speech was thus spreading and breaking up into daughter languages to the west, it was also spreading and breaking up to the east. North of the Carpathians and the Black Sea, Aryan-speaking tribes were increasing and spreading and using a distinctive dialect called Slavonian, from which came Russian, Serbian, Polish, Bulgarian, and other tongues; other variations of Aryan distributed over Asia Minor and Persia were also being individualized as Armenian and Indo-Iranian, the parent of Sanscrit and Persian. In this book we have used the word Aryan for all this family of languages, but the term Indo-European is sometimes used for the entire family, and “Aryan” itself restricted in a narrower sense to the Indo-Iranian speech.[89] This Indo-Iranian speech was destined to split later into a number of languages, including Persian and Sanscrit, the latter being the language of certain tribes of fair-complexioned Aryan speakers who pushed eastward into India somewhen between 3000 and 1000 B.C. and conquered dark Dravidian peoples who were then in possession of that land. § 2 What sort of life did these prehistoric Aryans lead, these Nordic Aryans who were the chief ancestors of most Europeans and most white Americans and European colonists of to-day, as well as of the Armenians,[90] Persians, and high-caste Hindus? In answering that question we are able to resort to a new source of knowledge in addition to the dug-up remains and vestiges upon which we have had to rely in the case of Palæolithic man. We have language. By careful study of the Aryan languages it has been found possible to deduce a number of conclusions about the life of these Aryan peoples 5000 or 4000 years ago. All these languages have a common resemblance, as each, as we have already explained, rings the changes upon a number of common roots. When we find the same root word running through all or most of these tongues, it seems reasonable to conclude that the thing that root word signifies must have been known to the common ancestors. Of course, if they have _exactly the same word_ in their languages, this may not be the case; it may be the new name of a new thing or of a new idea that has spread over the world quite recently. “Gas,” for instance is a word that was made by Van Helmont, a Dutch chemist, about 1625, and has spread into most civilized tongues, and “tobacco” again is an American-Indian word which followed the introduction of smoking almost everywhere. But if the same word turns up in a number of languages, and _if it follows the characteristic modifications of each language_, we may feel sure that it has been in that language, and a part of that language, since the beginning, suffering the same changes with the rest of it. We know, for example, that the words for waggon and wheel run in this fashion through the Aryan tongues, and so we are able to conclude that the primitive Aryans, the more purely Nordic Aryans, had waggons,