The great field, however, has been the _northern_ half of the New World; and the researches which have illustrated this have illustrated Polynesia and Africa as well. What may be called the _personal_ history of the United States Exploring Expedition, was published in 1845. The greatest mass, however, of philological _data_ ever accumulated by a single enquirer--the contents of Mr. Hale's work on the philology of the voyage--is recent. The areas which this illustrates are the Oregon territory and California; and the proper complements to it are Pickering's work on the Races of Man, the Smithsonian Contributions to Knowledge, and the last work of the venerable Gallatin on the Semi-civilized nations of America. Surely these are elements pregnant with modifying doctrines! II. For each of the great sections of our species, the present classification presents some differences, which if true, are important. Whether such novelties (so to say) are of a value at all proportionate to that of the fresh _data_, is a matter for the reader rather than the writer to determine--the latter is satisfied with indicating them. The extension of the Seriform group, so as to include the Caucasian Georgians and Circassians on the one side, and the Indians of Hindostan on the other; the generalization of the term Oceanic so as to include the Australians and Papuans--the definitude given to the Micronesian origin of the Polynesians--the new distribution of the Siberian Samöeids, Yeniseians, and Yukahiri--the formation of the class of Peninsular Mongolidæ, so as to affiliate the Americans (previously recognised as fundamentally of one and the same stock) with the north-eastern Asiatics--the sequences in the way of transition from the Semitic Arab to the Negro--the displacement of the Celtic nations, and the geographical extension given to the original Slavonians, are points for which the present writer is responsible; not, however, without previous minute investigation. The proofs thereof lie in tables of vocabularies, analyses of grammars, and ethnological reasonings, far too elaborate to be fit for aught else than a series of special monographs; not for a general view of the human species, as classified according to its varieties. This _classification_ is the _chief_ end of his work; and, more than anything else, it is this attempt at classification which has given a subordinate position to certain other departments of his subject. Where such is not the case, one of three reasons stands in its place to account for the matters enlarged upon, apparently at the expense of others. 1. The novelty of the information acquired. 2. The extent to which the subject has been previously either overlooked or thrown in the back-ground. 3. And, finally (though perhaps the plea is scarcely a legitimate one), the degree of attention which has been paid to the particular question by its expositor. LONDON, _July 25th, 1850_. BIBLIOGRAPHY.