In the matter of the indication and reckoning of time, however, we have not to do with a number of conceptions which may be supposed to be as numerous and as various as we please. At the basis lies an accurately determined and limited and indeed small number of phenomena, which are the same for all peoples all over the globe, and can be combined only in a certain quite small number of ways. These phenomena may be divided into two main groups: (1) the phenomena of the heavens--sun, moon, and stars--and (2) the phases of Nature--the variations of the climate and of plant and animal life, which on their side determine the affairs of men; these, however, depend finally upon one of the heavenly bodies, viz. the sun. The claim that the comparative ethnological method can be justified only when we are dealing with a narrowly circumscribed number of factors is therefore here complied with, owing to the very nature of the subjects treated. The comparative method does not shew how things have happened in a special case in regard to one particular people: it only indicates what _may_ have happened. But much is already gained if we can eliminate the impossibilities, since from the complete result of the development, no less than in other ways, we may obtain a certain basis for our deductions. For the investigation of primitive methods of time-reckoning no special astronomical or other technical knowledge is needed: in fact, such knowledge has rather played a fatal part by causing attention to be paid exclusively to the system of time-reckoning and leading to constant attempts to discover older and more primitive systems. _A priori_, indeed, we might venture to state that a system is always based upon previous data: unsystematic indications of time precede the system of time-reckoning. These modest beginnings have been obscured from view by the prejudice in favour of the systematic technical and astronomical chronology. The only absolutely necessary thing is a clear idea of the apparent motions of the heavenly bodies, i. e. the sun, the moon, and the most important of the fixed stars, and of the phases of the climate and the life of animals and plants, which give the units of the time-reckoning. For a statement of the course and phases of the heavenly bodies and the units of the time-reckoning given by these I refer to the article mentioned in the preface, the pertinent sections of which are here quoted:--