NE EARLY five-and-thirty years ago an idea, entered in a notebook, occurred to me regarding 'plurality of worlds,' which at that time I imagined went far to unsettle the prevailing belief, and to decide a question subsequently much agitated. The little paper in which it was embodied, lying so long dormant, has been the germ of the present work. From a jotting on it I see I had in 1860 observed that another had, in a published book, struck out a similar idea, and it has since been repeated by other writers. It was then, if not previously, I presume, I became desirous to take up and examine the whole subject in all its bearings ; but the incessant claims of an anxious profession altogether precluded the attempt, and it is only of recent date I have had it in my power to effect my purpose, and to bestow upon the subject the amount of study which I found to be requisite. I may not, however, conceal from myself that many |