the founding of a history of Western North America on the original sources which he had collected in order that it might constitute a foundation upon which future histories would be built.
"He who shall come after me," says he in the letter quoted above, "will scarcely be able to undermine my work by laying another and deeper foundation. He must build upon mine or not at all, for he can not go beyond my authorities for facts. He may add to or alter my work, for I shall not know or be able to tell everything, but he can never make a complete structure of his own."
That the volumes supervised by Mr. Bancroft should contain imperfections is in the nature of the case inevitable. Perfect historical estimates of contemporaries can not as a rule be made, and history based largely on personal reminiscence must contain errors of refraction which can be corrected only in the clearer light of later years. The handling of material by a writer who did not collect it, and who is likely to find the places and conditions dealt with strange to his experience, inevitable though it be in so large an undertaking, results in the writing of faulty history. The hastening of the work and the editorial revision of manuscripts by a manager desirous of pleasing subscribers, and impelled by various other motives of his own, are not circumstances likely to increase the accuracy of the work. But after allowance has been made for all inaccuracies which have crept in through these various avenues, we still have the fact that the histories are based upon sources which may be supplemented but can never be displaced. No greater mistake could be made, therefore, than to say that because they contain errors they are worthless. All must agree with the practical argument made by a thoughtful old pioneer of the writer's acquaintance that, in spite of all criticisms which may be passed upon the Bancroft his-
