Here therefore we have a natural year quite concretely and empirically given. Chronologically it is of no use nor indeed is it used: what method is resorted to will be shewn below. Attention must first be called, however, to an important point. The purely natural year is a circle which has no natural division, i. e. no beginning or end, the seasons following upon each other immediately; not so the agricultural year, which has both beginning and end. Here therefore there is a natural point of division, a new year, which appeared in some of the examples just given, and this is an extremely important point for time-reckoning. The vacant period between harvest and sowing presents some difficulty, and so both of these periods can be used as the beginning, as is done among the Thonga: otherwise the beginning of the year varies considerably, just because it can be arbitrarily determined[380]. The contradiction between length or duration of time and time-reckoning evidently here becomes apparent. The counting is not performed by means of these fluctuating empirical years, but the _pars pro toto_ method is employed, the years are counted by a season. As soon as it is said that some event took place at a definite time of the previous year, or will take place at some point in the following year, a counting of the years is thereby implied, although for an enumeration of this kind the conception of the year is not necessary. When it is said that something happened at the previous harvest, or will happen at the next dry season a counting of the years is no less implied, although seasons are reckoned instead of years, i. e. the _pars pro toto_ method is used. Thus it is, in fact, with all primitive and many highly developed peoples, and that not only when an event that took place at a definite time is spoken of, but also where the number of years alone is in question: in the latter case the reckoning is only performed from a favourite, conventionally selected season. The statement made for the Hottentots is significant for the kind of reckoning just mentioned. They keep in mind the age of their cattle from the calving and lambing periods[381]. Similarly we are told of the modern Arabians that the female camel is covered for the first time when she is four _rabi_ old (_rabi_ = the pasture-season in spring, when the camel foals), so that she foals in the fifth rabi[382].