Language is an important means of denoting the intricate thread of history in savage nations. Mr. Pritchard considers it more important than physiological structure and peculiarities. It is, at least, found often to reveal ethnological affinities, where both the physical type, and the light of tradition, afford but little aid. The words and names of a people, are so many clues to their thoughts and intellectual structure; this branch of the subject, indeed, formed the original germ of the present plan, which was at first simply geographical, and has been rather expanded and built upon, than, if we may so say, supplied the garniture of the edifice. In a class of transpositive languages, which are very rich in their combinations, and modes of concentrated description, it must needs happen, that the names of places would often recall both associations and descriptions of deep interest in contemplating the fate and fortunes of this unfortunate race. Without intruding upon the reader disquisitions which would be out of place, no opportunity has been omitted, from the consideration of their names, to throw around the sites of their former or present residence, this species of interest. But half the work would have been done, it is conceived, to have confined the work to North America; and it must necessarily have lost, by such a limitation, more than half its interest. We are just beginning in truth to comprehend the true character and bearing of that unique type of civilization which existed in Mexico, Peru, and Yucatan. The rude hand with which these embryo kingdoms of the native race were overturned, in consequence of their horrid idolatries, necessarily led to the destruction of much of their monumental, and so far as their picture writing reached, some of their historical materials, of both of which, we now feel the want. It is some relief, to know, as the researches of Mr. Gallatin, which are now in progress, demonstrate, that by far the greatest amount of the ancient Mexican picture writings, as they are embraced in the elaborate work of Lord Kingsborough, relate to their mythology and superstitions, and are of no historical value whatever. And if the portions destroyed in the Mexican and Peruvian conquests, were as liberally interspersed with similar evidences of their wild polytheism, shocking manners, and degraded worship, neither chronology nor history have so much to lament.