In modern times, the word _Iran_ for Persia and _Erin_ for Ireland are possible reminiscences of the original family appellation.
The Ayrans, long before the age of the Vedas or the Zend Avesta, were living as a pastoral people on the great plains east of the Caspian Sea.
What their condition was at that epoch is deduced by the following method: If it is found that the name of any fact is the same in two or more of the seven tribal languages of this stock, it is evident that the name was given to it before they separated.

For there is no reason to suppose that two nations living wide apart would have independently selected the same word for the same object.

For example, since we find that _house_ is in Sanskrit _Damn_ and _Dam_; in Zend, _Demana_; in Greek, [Greek: Domos]; in Latin, _Domus_; in Irish, _Dahm_; in Slavonic, _Domu_,--from which root comes also our English word _Domestic_,--we may be pretty sure that the original Aryans lived in houses.

When we learn that _boat_ was in Sanskrit _Nau_ or _nauka_; in Persian, _Naw, nawah;_ in Greek, [Greek: Naus]; in Latin, _Navis_; in old Irish, _Noi_ or _nai_; in old German, _Nawa_ or _nawi_; and in Polish _Nawa_, we cannot doubt that they knew something of what we call in English _Nau_tical affairs, or Navigation.

But as the words designating masts, sails, yards, &c.