The time-indications from the phases of the climate and of Nature are only approximate: they themselves, like the concrete phenomena to which they refer, are subject to fluctuation. Even in the tropics, where the regularity of the climatic changes is greater than in our latitudes, the beginning of the rains, the dry season, or monsoons may be to some extent advanced or retarded. In the temperate zones the fluctuations are very perceptible. In the year in which I write this (1916) the corn harvest has been delayed by nearly a month, not only on account of bad weather in harvest-time but also owing to the unusually low temperature of the past summer. Even the townsfolk notice that the days are shorter and the weather is colder than is usual at the time of harvest. Further, incidents of plant and animal life--e. g. the blossoming of certain trees and plants, the arrival of the migratory birds--vary somewhat in different years. In general primitive man takes no notice of these variations: the Banyankole, for instance, are indifferent as to whether the year is one or even three weeks longer or shorter, i. e. whether the rainy season opens so much earlier or later[465]. The days are not counted exactly, but the people are content with the concrete phenomenon. More accurate points of reference are however especially desirable for an agricultural people, since, although the right time for sowing can be discerned from the phenomena and general conditions of the climate, yet a more exact determination of time may be extremely useful. The possibility of such a determination exists--and that at a far more primitive stage than that of the agricultural peoples--in the observation of the stars, and especially in the observation of the so-called ‘apparent’ or, more properly, visible risings and settings of the fixed stars, the importance of which has already been explained (pp. 5 ff.) The observation of the morning rising and the evening setting is extraordinarily wide-spread, but other positions of the stars, e. g. at a certain distance from the horizon, are also sometimes observed[466]. The Kiwai Papuans also compute the time of invisibility of a star. When a certain star has sunk below the western horizon they wait for some nights during which the star is ‘inside’; then it has ‘made a leap’, and shews itself in the east in the morning before sunrise[467]. Any reader of the classics will be familiar with the risings and settings of the stars: Virgil, for example, mentions them often. With him however they are pre-eminently a traditional ornament of poetic style: the richest sources are the peasants’ rules of Hesiod, in which the stars are mentioned as time-indications along with phenomena of plant and animal life, and appear just as frequently as the latter, often in combination with them. But Homer not only knows several stars but is also acquainted with the rising and setting. A much quoted passage in the Iliad runs:--