Some of the subjects introduced may be familiar to the reader; but the Author hopes that sufficient novelty of detail will be found even in these, to render them acceptable, while they could not be wholly omitted in justice to the subject of which it was proposed to treat. The memoirs of the South Sea madness and the Mississippi delusion are more complete and copious than are to be found elsewhere; and the same may be said of the history of the Witch Mania, which contains an account of its terrific progress in Germany, a part of the subject which has been left comparatively untouched by Sir Walter Scott, in his "Letters on Demonology and Witchcraft," the most important that have yet appeared on this fearful but' most interesting subject.

Popular delusions began so early, spread so widely, and have lasted so long, that instead of two or three volumes, fifty would scarcely suffice to detail their history. The present may be considered more of a miscellany of delusions than a history, -- a chapter only in the great and awful book of human folly which yet remains to be written, and which Porson once jestingly said he would write in five hundred volumes! Interspersed are sketches of some lighter matters, -- amusing instances of the imitativeness and wrongheadedness of the people, rather than examples of folly and delusion.

Religious manias have been purposely excluded as incompatible with the limits prescribed to the present work; -- a mere list of them would alone be sufficient to occupy a volume.

In another volume should these be favourably received, the Author will attempt a complete view of the progress of Alchemy and the philosophical delusions that sprang from it, including the Rosicrucians of a bygone, and the Magnetisers of the present, era.