This is an OCR edition without illustrations or index. It may have numerous typos or missing text. However, purchasers can download a free scanned copy of the original rare book from GeneralBooksClub.com. You can also preview excerpts from the book there. Purchasers are also entitled to a free trial membership in the General Books Club where they can select from more than a million books without charge. Original Published by: The University of Chicago press in 1913 in 341 pages; Description: First published as thesis (Ph. D.) Columbia university, 1913.; Subjects: Science / History;