Thus, it is quite certain that, in Caesar’s time, Gaul was divided politically into three nationalities—­the Belgae, the Celtae, and the Aquitani; and that the last were very widely different, both in language and in physical characteristics, from the two former.  The Belgae and the Celtae, on the other hand, differed comparatively little either in physique or in language.  On the former point there is the distinct testimony of Strabo; as to the latter, St. Jerome states that the “Galatians had almost the same language as the Treviri.”  Now, the Galatians were emigrant Volcae Tectosages, and therefore Celtae; while the Treviri were Belgae.

At the present day, the physical characters of the people of Belgic Gaul remain distinct from those of the people of Aquitaine, notwithstanding the immense changes which have taken place since Caesar’s time; but Belgae, Celtae, and Aquitani (all but a mere fraction of the last two, represented by the Basques and the Britons) are fused into one nationality, “le peuple Francais.”  But they have adopted the language of one set of invaders, and the name of another; their original names and languages having almost disappeared.  Suppose that the French language remained as the sole evidence of the existence of the population of Gaul, would the keenest philologer arrive at any other conclusion than that this population was essentially and fundamentally a “Latin” race, which had had some communication with Celts and Teutons?  Would he so much as suspect the former existence of the Aquitani?

Community of language testifies to close contact between the people who speak the language, but to nothing else; philology has absolutely nothing to do with ethnology, except so far as it suggests the existence or the absence of such contact.  The contrary assumption, that language is a test of race, has introduced the utmost confusion into ethnological speculation, and has nowhere worked greater scientific and practical mischief than in the ethnology of the British Islands.

What is known, for certain, about the languages spoken in these islands and their affinities may, I believe, be summed up as follows:—­

I. At the time of the Roman conquest, one language, the Celtic, under two principal dialectical divisions, the Cymric and the Gaelic, was spoken throughout the British Islands.  Cymric was spoken in Britain, Gaelic in Ireland.

If a language allied to Basque had in earlier times been spoken in the British Islands, there is no evidence that any Euskarian-speaking people remained at the time of the Roman conquest.  The dark and the fair population of Britain alike spoke Celtic tongues, and therefore the name “Celt” is as applicable to the one as to the other.

What was spoken in Ireland can only be surmised by reasoning from the knowledge of later times; but there seems to be no doubt that it was Gaelic; and that the Gaelic dialect was introduced into the Western Highlands by Irish invaders.