by Aristotle
22 · Why are hounds least able to find the scent when a West wind is blowing? Is it because it disperses the scent most owing to the fact that of all the [15] winds it blows most continuously and down on to the earth?
23 · Why, when there are shooting stars, is it a sign of wind? Is it because they are carried along by the wind, and the wind occurs where they are, before it reaches us? For this reason also the wind rises in that quarter from which the stars are set in motion.
[20] 24 · Why is it that of all the winds the West wind drives the largest clouds? Is it because it blows from the open sea and over the deep, so that it collects clouds from a large area?
25 · Why are the winds strongest which are at their ending? Is it because when they expend themselves all at once, what remains is very little?12
[25] 26 · Why is it that, if the South-West wind (Lips) blows about the time of the equinox, rain results? Is it because the sun sets the winds in motion from any part of the universe in which it is? Hence the succession of the winds corresponds to the course of the sun. Now since the equinox is the boundary between winter and [30] summer, when it happens that the sun, according to the equinox as it appears to us, has passed the exact boundary or falls short of it and is rather in the wintry region, the result is that the winds from that region blow, of which the first is the South-West wind, which is naturally moist. Now when the sun is rather in the wintry region of the universe and stirs up the winds there, the result is that the typical conditions of winter result; one of which is wet weather. Again, since the [35] equinox is as it were winter and summer equally balanced, if anything is added to either one of them it causes a distinct inclination in one direction, just as happens in the case of equally balanced scales. But, since the South-West wind is of the wintry [943a1] order and naturally moist, its addition at the equinox causes an inclination towards winter and rainy weather; for rain is the wintry weather most akin to the wind that has begun to blow.
27 · Why are the South wind and the South-East wind (Eurus), which are [5] warmer than their respective contraries, the North wind and the West wind, more rainy, although water is engendered from the air by cold? For it is not true that the clouds form because the North wind thrusts them away from our part of the world; for the West and South-East winds both alike—for they are similarly at the sides of the world—drive away clouds from the quarter from which they blow, as also do all [10] the other winds. Is it because the more the heat exists outside, the more the cold is driven within? Or is it due in some degree to the quarter from which they blow that certain winds bring clear weather? For the South-East wind rises from the dawn (and the region is warm), while the West wind is situated towards the evening.13 But is there not a further reason, namely, that air, like water, cools most quickly and [15] thoroughly when it is previously heated? The air then brought by the South-East wind arrives warm from the rising sun, as does that brought by the South wind from the midday sun; when, therefore, they reach the colder region, they quickly condense and become massed into rain. And the South-East wind has a greater tendency to form rain, because it brings the air more directly from the sun and [20] equally hot; but the South wind is rainy as it ceases to blow, because the first air that is brought comes cold from the sea, whereas the last air, which is very warm, is brought14 from the land. Or is there not a further reason, namely, that the South wind is stronger as it ceases to blow (hence the proverb applied to it, ‘When the South wind begins . . . ’), and stronger winds are colder, and so the South wind [25] masses the clouds together at the end of its duration? Is not this why it is more rainy then than when it first begins to blow?
28 · Why do the winds, though they are cold, cause dryness? Is it because the colder winds cause evaporation? But why should they do so more than the sun? Is it because they carry off the vapour, whereas the sun leaves it where it is and [30] consequently causes more moisture and less dryness?
29 · Why does the North-East wind (Caecias) alone of all the winds attract the clouds towards itself, as the proverb has it, ‘Drawing it to himself, as Caecias draws clouds’? For the other winds simply drive forward the clouds from the quarter from which they blow. Is this phenomenon to be attributed to the fact that [35] the contrary wind blows at the same time? But would not this have been obvious, and is it not more likely that the North-East wind naturally follows a circular course? The other winds therefore blow round the earth, but the North-East wind [943b1] has the concave side of its course towards the heavens and not towards the earth, and so, blowing towards its source, it attracts the clouds to itself.
30 · Why is it that the wind blows cold in the early morning from rivers but [5] not from the sea? Is it because the sea extends over open spaces, but rivers are in narrow places? The breeze, therefore, from the sea is dispersed over a wide area and is consequently weak; whereas the breeze from a river is carried along in a mass and [10] is stronger and therefore naturally appears colder. Or is the reason other than this, namely, that the rivers are cold, but the sea is neither hot nor cold? Now a breeze or exhalation is due to the heating or cooling of liquids; for whichever of these two processes they undergo, evaporation takes place, and, when water evaporates, the resultant air is set in motion, and this is a breeze. That which is produced from cold [15] liquids naturally blows cold, while that which blows from very hot liquids cools and becomes cold. One would therefore find that all the rivers are cold, but the sea is neither very hot nor very cold. That which blows from it therefore is not cold, because the sea is not itself very cold, nor does it cool quickly because the sea is not [20] very hot.
31 · Why is the West wind always considered to bring fair weather and to be the pleasantest of the winds? So, for instance, Homer says that in the Elysian Plains.
Ever the breezes blow of the Zephyr.15
Is it because in the first place it contains a mixture of air? For it is neither hot like [25] the winds from the south and east, nor cold like that from the north, but is16 on the boundary between the cold and the hot winds; and, being near to them both, it partakes of their qualities, and is consequently temperate and breathes most of spring. Furthermore, the winds change either into their contraries or into those on [30] their right; blowing therefore after the North wind (for the west is on the right of the north), it enjoys a good reputation, as being mild as compared with an inclement wind. Also as soon as wintry weather ceases, fine weather usually follows; and the North wind is a wintry wind. [The East wind, though it lies between the warm and the cold winds, partakes less of them; for, when it blows, it sets in motion the winds [35] towards the south (for when it changes it does so in that direction), but though it sets them in motion it does not mingle with them. The West wind is set in motion by the South winds, and when it blows it sets the North winds in motion; for there the [944a1] succession of the winds ceases. Hence the West wind, constituting as it does the end of some winds and the starting-point of others, justly is and is considered to be a pleasant wind.]17
32 · Why does the South wind blow at the time of the dog-star? Is it because a sign occurs at the setting or rising of any star, and especially of the [5] dog-star? It is clear then that the wind blows most at the time of and after its rising. And since it causes stifling heat, it is only natural that the hottest winds should be set in motion when it rises; and the South wind is hot.
33 · Why does the West wind blow towards evening and not in the early [10] morning? Is the sun at its rising and setting usually the cause of breezes? For when it concocts and dissolves the air, which is moist, by thoroughly heating it, it dissolves it into breath; and if the air is full of breath, it becomes still more evaporated by the sun. When, therefore, the sun is in the east, it is far away from the West wind, for [15] the latter blows from the setting sun; but when the sun is already near its setting, the breath is then thoroughly dissolved, and from midday onwards and towards evening the sun is most suitably situated for heating and dissolving the air. It is for this reason also that the East win
d begins to blow in the early morning; for since the air above the earth becomes charged with moisture during the night and owing to its [20] weight approaches the earth, the sun from dawn onwards dissolves it and sets in motion first the air which is nearest to itself. Now the East wind gets its name Apeliotes because it is the wind which blows from the rising sun.
34 · Why is it that when the sun rises the winds both rise and fall? Is it [25] because a wind is the movement either of the air or of moisture carried up? Now this movement, when it is only slight, is quickly absorbed by the sun, so that no wind occurs; but when it is greater, the movement is increased when the sun rises, for the sun is a source of movement. [30]
35 · Why does the West wind blow in the evening? Is it because all the winds blow when the sun disperses the moisture? For the moisture being already in a mass, the power of heat, when it approaches it, concocts it.18 Now the West wind blows from the setting sun; it is only natural then that it should rise in the evening, for then the sun reaches the quarter proper to that wind. [35]
The North and the South winds are the most frequent of winds, because, when one contrary is overcome by its direct contrary, it is least able to continue, whereas it is better able to resist a wind blowing against it from an angle. Now the South and [944b1] the North winds blow from regions on either side of the sun’s course, while the other winds blow rather in a straight line with it.
36 · Does the wind come from a source, as water does, and is it unable to rise to a higher level than that source, or is this not so? And does it come from a single [5] point or from a wider area? There are indeed in the wind certain similarities to that which seems to occur in water; for water flows faster when it travels downhill, whereas it stagnates on flat and level ground, and the winds act similarly, for on [10] promontories and high ground the air is always in motion, whereas in hollows it is often at rest and there is a calm. Moreover on exceedingly high mountains there is no wind at all—on Mount Athos, for example, amongst others, as is proved by the fact that offerings which persons sacrificing leave there one year are, so it is said, [15] found there still in the following year. It is clear then that the course of the wind starts as it were from a source of some kind. It cannot, therefore, rise any higher. Hence the above phenomenon occurs on high mountains, to which what happens to water would be a close parallel; for apparently neither a strong flow of water nor a [20] violent wind is found in high mountains.
37 · Why is it that when the South wind blows the sea becomes blue, but when the North wind blows it becomes dark? Is it because the North wind disturbs the sea less, and that which is less disturbed appears to be all black?
[25] 38 · Why do the South winds when they blow gently cause no overclouding, but when they become strong overcloud the sky? Is it because, when they blow gently, they cannot produce many clouds? They therefore cover only a small area with cloud; but, when they blow strongly, they thrust along many clouds, and therefore seem to cause more overclouding.
[30] 39 · Why is the North wind strong when it begins to blow, but weak as it ceases, whereas the South wind is weak when it begins, but strong as it ceases? Is it because the North wind is near to us and the South wind distant? The former then, when it begins, blows immediately in our part of the world, whereas the beginning of the latter becomes dispersed owing to the long time it takes to travel, and little of [35] its first breath reaches us; and we feel the end of the North wind, but that of the South wind not at all. It is, therefore, only natural that the North wind should be weak as it ceases (for the end of all things is weak), while the South wind is not weak at its close, since we do not feel its ending at all.
[945a1] 40 · Why do alternating winds blow where there are bays, but not where there is a wide expanse of open sea? Is it because the wind, when it pours into the bays, is less broken up and travels for the most part in a collected mass, whereas [5] over open expanses of sea the land-winds tend to be broken up as they begin to flow, and when they move the same thing happens to them, because they are free to travel in many directions? For an alternating wind is the reflux of a land-wind.19
41 · What is the origin of the saying,
When the South wind begins and when Boreas ceases his blowing?
Is it because the North wind, owing to the fact that we live near it and our [10] habitation is towards the pole, immediately blows strongly, for it is with us as soon as it begins? Hence, as it ceases, it blows pleasantly; for it then blows weakly. The South wind, on the other hand, because it is far away, reaches us later in greater strength.
42 · Why is it that men feel heavier and weaker when the wind is in the south? Is it because moisture becomes abundant instead of scanty, being melted by the heat, and moisture, which is heavy, takes the place of breath, which is light, and [15] under these conditions men’s strength becomes languid?
43 · Why are men hungrier when the wind is in the north than when it is in the south? It is because the North winds are colder?
44 · Why does the South wind not blow in Egypt itself in the regions towards the sea nor for the distance of a day and a night’s journey inland, while in the [20] regions beyond Memphis and for the distance of a day and a night’s journey it blows freshly; and does not blow to the west for the distance of two days’ and two nights’ journey, while to the east the South-West wind (Lips) blows? Is it because Egypt in its lower regions is hollow, so the South wind passes over above it, but to the south and farther away the regions are loftier? [25]
45 · Why is it that the South wind is weak when it begins to blow, but becomes stronger as it ceases, while with the North wind the contrary is the case, hence the proverb,
Sail when the South wind begins and when Boreas ceases his blowing?
Is it because we dwell rather towards the pole than towards the midday sun, and the North wind blows from the pole, while the South wind blows from the midday sun? [30] It is only natural, therefore, that the North wind, when it begins, immediately attacks with violence the regions nearer to it, and afterwards transfers its violence to the dwellers farther south. The South wind, on the contrary, when it begins, presses upon those who dwell towards the midday sun, and, when it has passed them by, blows freshly upon those who dwell towards the pole. [35]
46 · What is the origin of the saying,
Straightway the winter comes, if the South wind call to the North wind?
Is it because it is the nature of the South wind to collect clouds and much rain? When therefore the North wind blows under these conditions, since there is [945b1] abundant material, the North wind freezes it and brings on the winter. Hence the saying,
When Boreas findeth the mire, soon cometh the season of winter.
Now mud and rain in general are usually, if not invariably, due to the South wind.
[5] 47 · Why does the North wind follow quickly upon the South wind, but not the South wind upon the North wind? Is it because the North wind arrives from near at hand, but the South wind from a distance, since our habitation is towards the north?
48 · Why is it that the winds are cold, although they are due to movement caused by heat? Is movement caused by heat not invariably hot, but only when it [10] occurs in a certain manner? If it comes forth in a mass, it burns with its heat the very thing which emits it; but if it passes out gradually through a narrow space, it is itself hot, but the air which is set in motion by this process completes the movement in accordance with whatever was its original nature. This can be seen in the human [15] body; for there is a saying that from the same organ we breathe both hot and cold, but this is untrue, since all that proceeds from the mouth is hot, as is shown by the fact that it appears hot if the hand is placed close to the mouth. It is the manner in which it comes forth which makes the difference. For if in yawning we emit breath from a wide opening, it appears hot because we can feel it; but if it be emitted [20] through a narrow opening, being more violent, it impels the air in its immediate neighbourhood, which in its turn impels the adjoining air.
If the air is cold, its movement is also cold. May not the same thing happen also in the winds, and their first movement be through a narrow channel and then set in motion the adjoining air, and then other air begin to rush onwards? So in the summer the winds are hot, [25] in winter they are cold, because in each case this is the temperature of the air which is already there; for that the air does not follow this course because it is either set in motion by itself or overpowered by the heat, is clear not only from the fact that it heats the winds when there is more heat in it, but also because it was originally [30] being carried upwards. For fire is of this nature; whereas cold naturally travels downwards. The winds move horizontally and for good reason; for since the heat presses upwards and the cold downwards and neither prevails, and the air cannot remain still, it is only natural that its motion should be sideways.
[35] 49 · Why are the South winds cold in Libya as the North winds are with us? Is it primarily because the sources of these winds are respectively nearer to us and to them? For if, as we have already said, the winds pass through a narrow channel, they will be colder to those who are nearer to them owing to the violence of their [946a1] movement; for when their movement proceeds farther, they become dispersed. Hence the North winds are cold in our part of the world, because we are nearer to them and dwell quite near the pole.
50 · Why is it that those South winds which are dry and do not bring rain [5] cause fever? Is it because they engender unnatural moist heat in the body? For they are by nature moist and hot, and this causes fever, which is due to a combined excess of these two things. When, therefore, the South winds blow under the influence of the sun without bringing rain, they engender this condition in us;20 whereas, when they bring rain with them, the rain cools us.