As intimated, however, in spite of this underlying sameness, there is wide diversity in the tongues themselves. Where we cannot find sufficient coincidences of words and grammar in two languages to admit of supposing that under the laws of linguistic science they are related, they are classed as independent stocks or families. Of such there are about eighty in North and as many in South America. These stocks offer us, without doubt, our best basis for the ethnic classification of the American tribes; the only basis, indeed, which is of any value. The efforts which have been heretofore made to erect a geographic classification, with reference to certain areas, political or physical; or a craniological one, with reference to skull forms; or a cultural one, with reference to stages of savagery and civilization, have all proved worthless. The linguistic is the only basis on which the subdivision of the race should proceed. Similarity of idioms proves to some extent similarity of descent and similarity of psychic endowments. Of course, there has been large imposition of one language on another in the world’s history; but never without a corresponding infiltration of blood; so that the changes in language remain as evidence of national and race comminglings. I select, therefore, the linguistic classification of the American race as the only one of any scientific value, and, therefore, that which alone merits consideration. The precise number of linguistic stocks in use in America at the discovery has not been made out. In that portion of the continent north of Mexico the researches of the Bureau of Ethnology of the United States have defined fifty-nine stocks, no less than forty of which were confined to the narrow strip of land between the Rocky mountains and the Pacific ocean. For convenience of study I shall classify all the stocks into five groups, as follows:-- I. The North Atlantic Group. II. The North Pacific Group. III. The Central Group. IV. The South Pacific Group. V. The South Atlantic Group. This arrangement is not one of convenience only; I attach a certain ethnographic importance to this classification. There is a distinct resemblance between the two Atlantic groups, and an equally distinct contrast between them and the Pacific groups, extending to temperament, culture and physical traits. Each of the groups has mingled extensively within its own limits, and but slightly outside of them. Each is subject to conditions of temperature, altitude and humidity, which are peculiar to itself, and which have exerted definite influences on the constitution and the history of its inhabitants. Such a subdivision of the race is therefore justified by anthropologic considerations. NORTH AMERICAN TRIBES. I. THE NORTH ATLANTIC GROUP. 1. THE ESKIMOS.