It must, however, be confessed that O’Brien is not always so much in harmony with modern thought, and that his reasoning from analogies of language appears to us, occasionally, neither sound nor ingenuous. Perhaps it would be more correct to say that he sometimes, without meaning deception, allows enthusiasm to entice him across the line between fact and fiction. In this respect he is not, perhaps, less scrupulous than the average etymologist; but even admitting the veniality of his offence, it seems to us that the philological is the weakest portion of his book. In his hands Grimm’s then recently discovered “law of the mutation of consonants” was, as we think, too often strained to cover most questionable derivations, nor did he shrink, apparently, from coining forms of words to suit his purpose. As instances of this we may point to his otherwise skilful treatment of the name _Hibernia_ at p. 128, where, without any authority that we are aware of, he employs the form νηος for υῆσος, evidently with a view to strengthen his case; also, to his wonderful evolution of the word _Lingam_, at p. 284. But whilst the reader will probably accept his statements on this head with caution, admiration of his skill in detecting analogies which only require pointing out to secure our assent, cannot be withheld. That he had in him the making of a great philologist, is beyond question; and that in course of time, had his life been spared, he would have made this branch of his argument really formidable, is very probable. Even as it stands, we may be undervaluing its merit: philology is not an exact science, and one can rarely be sure of one’s ground therein from day to day. But, judging the matter by such light as we possess, it seems to us that the least valuable part of O’Brien’s book is that upon which he evidently prided himself most: others may, possibly on better grounds, be of a different opinion, and we gladly leave this portion of the book to speak for itself. * * * * *