in Balliol College and in the University of Oxford who during fifty years have been the best of friends to me these volumes are inscribed in grateful recognition of their never failing attachment.

The additions and alterations which have been made, both in the Introductions and in the Text of this Edition, affect at least a third of the work.

Having regard to the extent of these alterations, and to the annoyance which is naturally felt by the owner of a book at the possession of it in an inferior form, and still more keenly by the writer himself, who must always desire to be read as he is at his best, I have thought that the possessor of either of the former Editions (1870 and 1876) might wish to exchange it for the present one. I have therefore arranged that those who would like to make this exchange, on depositing a perfect and undamaged copy of the first or second Edition with any agent of the Clarendon Press, shall be entitled to receive a copy of a new Edition at half-price.