It has been shown by Dr. Prichard that the population of Islands has been derived from the neighbouring Continents, and that the population of the more distant Islands has been derived in like manner from those which are nearer to the common source of migration. It is highly unreasonable to assume that Ireland has formed an exception to this general rule, considering that the common basis of the Irish and ancient British or Welsh languages are confessedly the same, unless it can be proved that the accompanying differences are such as to require the solution Lhuyd has suggested. Here, then, the question arises, are the features of difference between the Welsh and Irish languages more numerous or more fundamental, in relation to the interval of time that has elapsed since the Roman Invasion of Britain, than the varieties of dialect among the Scandinavian nations are in relation to the period that has elapsed since the colonization of Iceland? They are not! It will thence be seen that Lhuyd’s theory, as to the remote date of the separation of the Gaelic or Irish from the British or Cymraeg branch of the Celts, is founded on an exaggerated conception of the stability of Human Tongues; and that the abandonment by various septs of different synonymes used conjointly by their common forefathers will satisfactorily account for the differences between the Welsh and Irish, to which he attaches so much weight. It will be perceived, for example, that in the Icelandic, of which the existence commenced in the ninth century, and the Continental Scandinavian from which it then sprang, totally different terms are used for “Water,” the very instance to which Lhuyd especially adverts, as regards the languages of the Welsh and Irish, whom we know to have existed as separate nations in the time of Cæsar eighteen centuries ago!