In this investigation, indeed, historical circumstances may often occur--such as the popular commotions and intermixture of nations happening at all periods of the world--by which the question of the origin and affinity of different races undergoes considerable modifications, and the whole subject is rendered unsusceptible of a systematic division and arrangement. It often happens that one race adopts the language of another, without on that account losing its national identity, or being totally confounded with the other; for, on the contrary, its moral or intellectual character bears the clear traces of its original descent; so that here, at least, language alone will decide nothing. Often a less numerous tribe will stamp its own native moral and intellectual character on a whole people. In general the descent of nations can be clearly traced and demonstrated in those cases only, where the race has been kept up pure, and all marriage and connection with other nations been strictly prevented. But such has been the case among certain nations only; and even in those countries, where it was the law, it was not in every instance rigidly observed, nor constantly maintained; as is exemplified in the frequent intermarriages of the Hebrews with the Phœnicians, severely prohibited as such intermarriages were. The ancient law-givers attached, indeed, a very high importance to lineage, as is proved by all those restrictive laws on marriage, which were destined to preserve the purity of descent; but they set a far higher value on the patrimonial inheritance of ancient customs, institutions, doctrines, and intellectual qualities, as constituting the true essence of national character, and determining the rank which one race should hold above another. By Moses, in particular, this intellectual character of the different races--their feelings--modes of thinking--the whole spirit which animated them, in a word--the chain of sacred tradition, and its transmission and preservation among the different nations--all these are regarded of primary importance, and they alone furnish us with a clue to the discovery of his views.