It is neither desirable nor possible here to examine or illustrate in full the essence of this mighty faculty. Such an examination would require a review of the whole field of literature, and would alone demand a volume. Our present task is not to explain or exhibit full portraiture of this function of the mind in all its relations, but only to obtain some certain tests by which we may determine whether it be very imagination or no, and unmask all impersonations of it, and this chiefly with respect to art, for in literature the faculty takes a thousand forms, according to the matter it has to treat, and becomes like the princess of the Arabian tale, sword, eagle, or fire, according to the war it wages, sometimes piercing, sometimes soaring, sometimes illumining, retaining no image of itself, except its supernatural power, so that I shall content myself with tracing that particular form of it, and unveiling those imitations of it only, which are to be found, or feared, in painting, referring to other creations of mind only for illustration. Sec. 2. The works of the metaphysicians how nugatory with respect to this faculty. Unfortunately, the works of metaphysicians will afford us in this most interesting inquiry no aid whatsoever. They who are constantly endeavoring to fathom and explain the essence of the faculties of mind, are sure in the end to lose sight of all that cannot be explained, (though it may be defined and felt,) and because, as I shall presently show, the essence of the imaginative faculty is utterly mysterious and inexplicable, and to be recognized in its results only, or in the negative results of its absence, the metaphysicians, as far as I am acquainted with their works, miss it altogether, and never reach higher than a definition of fancy by a false name. What I understand by fancy will presently appear, not that I contend for nomenclature, but only for distinction between two mental faculties, by whatever name they be called, one the source of all that is great in the poetic arts; the other merely decorative and entertaining, but which are often confounded together, and which have so much in common as to render strict definition of either difficult. Sec. 3. The definition of D. Stewart, how inadequate.