characterized by a secularization of human interests. As early as the sixth century B.C., the great political organizer of Athens, Clisthenes, made an attempt to divide the year into ten months instead of twelve. The attempt miscarried, just as did the analogous one on the part of the first French Republic to introduce a week of ten days. As a matter of fact, objective measurements of time are derived from the heavens and not from man. On the other hand, our measurement of terrestrial spaces and our grouping of populations depend entirely upon ourselves, and therefore naturally conform to human characteristics. In these cases, it is the decimal system that is used. In view of the fact that the number ten was deliberately adopted, this number has been thought to represent an idea that emanated from a single source. Since the organization effected by Clisthenes and that of Servius Tullius in Rome fall approximately within the same century, it has been believed that in these cases, especially, we may assume this fundamental idea of division to have been borrowed. The very extensive distribution of the decimal system, however, militates against the probability of this supposition. Thus, the Book of Exodus no longer speaks of the legendary twelve tribes of Israel but tells of only _ten_ tribes. We likewise hear of groups of one hundred, and of more extensive groups consisting of one thousand. These divisions also recur among the Germanic peoples, and in the far-distant realm of the Peruvian Incas. Among the latter, however, there are also distinct traces of a totemic tribal organization that antedated the invasion of the Incas. This was the foundation upon which the Inca kings and their officials finally reared an organization consisting of groups of ten, one hundred, and one thousand--indeed, the latter were even brought together to form groups of ten thousand. In certain cases, such systems may perhaps have been introduced from without or may, in part, have been acquired through imitation. Nevertheless, the supposition that they all emanated from a single region is doubtless just as improbable as is the view that the decimal system in general had but a single origin. This new grouping of the population is closely bound up with the conditions of political society. It is dependent upon _two_ motives, which, though not universally operative at first, became so the very moment that political society took its rise. The first motive is of a subjective nature. It consists in an increased facility in the use of the decimal mode of counting, as a result of which larger groups, consisting of multiples of ten, are formed: besides the single group of ten, it must have become possible to conceive of groups of one hundred, one thousand, and, in rare cases, even of one hundred thousand. The other motive is objective in character. There are changes in the external conditions of life such as to demand more comprehensive and at the same