The following pages were written for the Month, but in the course of writing extended themselves beyond the limits of a magazine article; the third chapter more particularly becoming too elaborate in form for suitable publication in a periodical. I have, therefore, preferred to publish them separately. As, however, it would have involved too much trouble to have rewritten and recast the articles, I have printed them in their original form, as addressed to the readers of the Month. The subject, at least, is a curious and interesting one and Mr. Donnelly's work, which was the occasion of the articles being written, contains much curious specula tion, and is written in a style calculated to give zest to the inquiry. It has had a wide circulation.