The book may have numerous typos or missing text. It is not illustrated or indexed. However, purchasers can download a free scanned copy of the original rare book from the publisher's website. You can also preview the book there.Purchasers are also entitled to a trial membership in the publisher's book club where they can select from more than a million books for free.Original Publisher: Carnegie Institution of Washington Publication date: 1916Subjects: EducationResearch; Science; Education / Teaching Methods