But, notwithstanding the occurrence of some features of difference, it is indisputable that there exists a close specific affinity between the Irish and Welsh Languages, which renders the common origin of the nations who speak them evident. The original identity of the Irish and Welsh Languages was established as far back as the commencement of the eighteenth century, by the investigations of the excellent Archæologist, Edward Lhuyd, who spent five years in travelling through the various Celtic regions, and whose comparison of the dialects of Wales, Cornwall, Armorica, the Highlands of Scotland, and the Isle of Man, is not inferior either in soundness of reasoning, or in patient, extensive, and honest research, to the best German works of the present day. But although the writings of Lhuyd may be said to have established the original unity of the Welsh and Irish races, since the publication of his work, a peculiar opinion has been adopted by some learned men with regard to the _time_ of their original separation. Of this opinion, Edward Lhuyd was himself the first advocate; his conclusion was that though the Irish and British Celts were both descendants from one stock, they must have been separated into two distinct Tribes before their arrival in the British Islands. The Gaelic or Irish Tribe he supposes to have preceded the Welsh or British Tribe, by whom he conceives them to have been gradually driven to the West, as the Britons were by the Saxons in subsequent ages. Lhuyd’s grounds are as follows: The most ancient names of Rivers and Mountains in the Island of Britain are very generally composed of terms still preserved in the Welsh or Ancient British Tongue. But there are some remarkable exceptions, and in these instances it frequently happens that the Names may be clearly identified with Words still preserved in the Irish or Gaelic branch of the Celtic. For example, the names of the British rivers, the Usk and the Esk, are particularly noticed by Lhuyd; these names are identical with “Uisge, Eask,” the Irish term for “Water.” This word, he observes, does not exist in the Welsh, and he had looked for it in vain in the sister dialect of Armorica; but, he adds, it is still retained by the Irish or Gaelic. Hence, he suggests that the Irish or Gaelic branch of the Celts must have colonized the Island of Britain before the arrival of the Cymry or Welsh branch, by whom, as he conceives, they were expelled, after having conferred names on the principal localities.