It is clear, from these considerations, that the three...

It is clear, from these considerations, that the three methods of classifying mankind-that according to physical characters, according to language, and according to culture-all reflect the historical development of races from different standpoints; and that the results of the three classifications are not comparable, because the historical facts do not affect the three classes of phenomena equally. A consideration of all these classes of facts is needed when we endeavour to reconstruct the early history of the races of mankind.