Hesiod says that at the time when the thistle blooms and the cricket chirps Sirius burns heads and knees[478], and that when the late autumn rains come men feel relieved, since the star Sirius is not passing over their heads for so long a time but uses the night more[479]. Commentators of classical times have indeed here taken Sirius to mean the sun. But wrongly; for Sirius, whose rising introduces the time of greatest heat, is for the Greeks the cause of the heat, just as the Pleiades are for the Australians, and as all stars are held to be the causes of those climatic changes which are connected with any of their risings or settings[480]; when Sirius rises earlier, i. e. remains in the heavens for some hours during the night-time, the heat declines. The other passages are:--vv. 564 ff., evening rising of Arcturus (60 days after the winter solstice, Feb. 24, Julian), followed by the coming of the swallow, messenger of spring, before this time the vines should be pruned; vv. 597 ff., the winnowing of the harvested corn at the morning rising of Orion (July 9); vv. 609 ff., when Orion and Sirius are in the middle of the heavens and the dawn sees Arcturus (morning rising Sept. 18), it is the time of the vine-harvest; vv. 615 ff., at the (morning) setting of the Pleiades (Nov. 3), of the Hyades, and of Orion (Nov. 15) it is time to think about sowing; vv. 619 ff., when the Pleiades, fleeing from Orion, fall into the sea, storms rage, and the ship should be drawn up on land. Alcaeus says:--“Drink wine, for the star (viz. Sirius) revolves”[481]. The time-indications from the stars are therefore much older in Greece than the lunisolar calendar, and always existed alongside of the latter--which was of a religious and civil character--as the calendar of peasants and seamen, who must hold to the natural year and its seasons. The watchman who speaks the prologue of the _Agamemnon_ of Aeschylus says:-- “ ... On elbow bent, watching, as ’twere a dog, I mark the stars in nightly conclave meet. And those bright constellations, without peer, Lords paramount in heaven, that winter bring And summer in their train for mortal men, Right well I know them as they come and go”[482]. The discovery of star-observation and of its use in time-reckoning and navigation is ascribed to the heroes Prometheus and Palamedes. The latter is regarded by the tragic poets as the founder of all the elements of intellectual culture, and so also of the science of the stars[483]. And Prometheus, who glories in having brought to men every advance in civilisation, includes therein the knowledge of the risings and settings of the stars:-- “Of winter’s coming no sure sign had they, Nor of the advent of the flowery spring, Of fruitful summer none: so fared through each, And took no thought, till that the hidden lore Of rising stars and setting I unveiled”[484].