Those are the coldest winds which are said to blow from the seven stars, and Corus, which is contiguous to them; these also restrain the others and dispel the clouds. The moist winds are Africus, and, still more, the Auster of Italy. It is said that, in Pontus, Cæcias attracts the clouds. The dry winds are Corus and Vulturnus, especially when they are about to cease blowing. The winds that bring snow are Aquilo and Septemtrio; Septemtrio brings hail, and so does Corus; Auster is sultry, Vulturnus and Zephyrus are warm. These winds are more dry than Subsolanus, and generally those which blow from the north and west are more dry than those which blow from the south and east. Aquilo is the most healthy of them all; Auster is unhealthy, and more so when dry; it is colder, perhaps because it is moist. Animals are supposed to have less appetite for food when this wind is blowing. The Etesiæ generally cease during the night, and spring up at the third hour of the day[2]. In Spain and in Asia these winds have an easterly direction, in Pontus a northerly, and in other places a southerly direction. They blow also after the winter solstice, when they are called Ornithiæ[3], but they are more gentle and continue only for a few days. There are two winds which change their nature with their situation; in Africa Auster is attended with a clear sky, while Aquilo collects the clouds[4]. Almost all winds blow in their turn, so that when one ceases its opposite springs up. When winds which are contiguous succeed each other, they go from left to right, in the direction of the sun. The fourth day of the moon generally determines their direction for the whole of the monthly period[5]. We are able to sail in opposite directions by means of the same wind, if we have the sails properly set; hence it frequently happens that, in the night, vessels going in different directions run against each other. Auster produces higher winds than Aquilo, because the former blows, as it were, from the bottom of the sea, while the latter blows on the surface; it is therefore after south winds that the most mischievous earthquakes have occurred. Auster is more violent during the night, Aquilo during the day; winds from the east continue longer than from the west. The north winds generally cease blowing on the odd days, and we observe the prevalence of the odd numbers in many other parts of nature; the male winds are therefore regulated by the odd numbers[6]. The sun sometimes increases and sometimes restrains winds; when rising and setting it increases them; while, when on the meridian, it restrains them during the summer. They are, therefore, generally lulled during the middle of the day and of the night, because they are abated either by excessive cold or heat; winds are also lulled by showers. We generally expect them to come from that quarter where the clouds open and allow the clear sky to be seen. Eudoxus[7] supposes that the same succession of changes occurs in them after a period of four years, if we observe their minute revolutions; and this applies not only to winds, but to whatever concerns the state of the weather. He begins his lustrum at the rising of the dog-star, in the intercalary year. So far concerning winds in general.