HISTORY OF THE WINDS
THE FIRST TITLE IN THE NATURAL AND EXPERIMENTAL
FOR THE FOUNDATION OF PHILOSOPHY
WHICH IS THE THIRD PART OF THE INSTAURATIO MAGNA.
HISTORY OF THE WINDS.
INTRODUCTION OR PREFACE.
To men the winds are as wings. For by them men are borne and fly, not indeed through the air but over the sea; a vast gate of commerce is opened, and the whole world is rendered accessible. To the earth, which is the seat and habitation of men, they serve for brooms, sweeping and cleansing both it and the air itself. Yet they damage the character of the sea, which would otherwise be calm and harmless; and in other respects they are productive of mischief. Without any human agency they cause strong and violent motion; whence they are as hired servants to drive ships and turn mills, and may, if human in-dustry fail not, be employed for many other purposes. The nature of the winds is generally ranked among the things mys-terious and concealed; and no wonder, when the power and nature of the air, which the winds attend and serve (as repre-sented by the poets in the relation of zEolus to Juno), is entirely unknown. They are not primary creatures, nor among the works of the six days; as neither are the other meteors actually ; but produced according to the order of creation.
TRANSLATION OF THE PARTICULAR TOPICS;
Articles of Inquiry Concerning the Winds.
1. Describe the winds according to the method observed at sea, and give them names either ancient or modern; but let them be constant and invariable.
Winds are either General, Periodical, Attendant, or Free. By the General winds, I mean those which blow always; by the Periodical, I mean those which blow at certain times; by the Attendant, those which blow.more frequently; and by the Free,. those which blow indifferently.
2. Are there any general winds and actual motions of the General Winds. air? If such things be, in what order of motion, and in what places do they blow?
3. What winds are annual, or periodical, and in what coun-Periodical tries ? Is any wind so precisely periodical as to
Winds. return regularly on certain days and hours like the tide of the sea?
4. What winds are attendant and haunters of particular Attendant regions? at what times do they blow in those regions? what winds blow in the spring, summer, autumn, and winter? which are equinoctial, and which solatitial winds? which are morning, which noonday, which evening, and which night winds?
5. What is the nature of sea winds, and what that of land winds? And here carefully mark the differences between sea and land winds, as well those which blow on as those which blow from the sea and land.
6. Are there not winds blowing from every quarter of the Free winds. heaven?
WINDS do not vary much more in the quarters they blow from than in their qualities. Some are strong, others gentle; some constant, others variable; some hot, others cold; some moist and relaxing, others dry and binding; some collectclouds and are rainy or stormy, others disperse them and are fair.
7. Inquire and report to which of the forementioned kinds
The nitrint each wind belongs, and how they vary according to countries and places.
The local origins of winds are three in number; for they are either sent down from above, or they spring out of the earth, or they are collected in the body of the air.
8. Inquire of the winds according to these three origins;
namely, which of them are sent down from what is wind'. termed the middle region of the air; which breathe forth from the hollows of the earth, whether they rush out in a body, or exhale imperceptibly and by degrees, and then collect as streams into a river; lastly, which of them are generated indiscriminately by the swelling or expansion of the contiguous air?
The generations of the winds are not only original, but also accidental; that is, arising from the compressions, percus-sion, and repercussions of the air.
9. Inquire into these accidental generations of the winds. Aoridental Properly they are not generations, for they rather Generations of winds. increase and strengthen the winds than create and excite them.
So much then for the community of winds. But there are some extraordinary and prodigious winds, as fiery winds, whirl-winds, and hurricanes. These prevail on earth. But there are likewise subterranean winds, whereof some are vaporous and mercurial; as are felt in mines; others are sulphureous; and find vent in earthquakes, or burst out from volcanoes.
10. Inquire into these extraordinary and prodigious winds, Winds, and and into all the wonderful properties of winds.
From the kinds of winds let the inquiry pass on to the things which help to produce them (I do not say efacients of them, for that is more than I mean; nor concomitants, for that is less, but confacients, things which help to make them); and those which are supposed to excite or calm them.
11. Of astrological considerations touching the winds inquire sparingly, neither care thou for the over curious schemes of the heaven; only do not neglect the more evident manifest observations of the winds increasing at the rising of certain stars, at the eclipses of luminaries, or at the conjunctions of planets; and how far they depend on the paths of the sun or moon.
12. What do meteors of different kinds contribute to the winds? What do earthquakes, showers, and the meeting of the winds together, contribute ? For these things are linked together, and depend one upon the other.
13. What do different vapours and exhalations contribute? which of them is most productive of winds, and how far is the nature of winds influenced by their matter?
14. What do earthly things and things which take place on earth contribute to the winds ? What do mountains and the melting of snow upon them, or vast icebergs which float and are borne about in the sea everywhere, contribute? What do the differences of soil or land (if in large tracts), as marshes, sands, woods, plains, contribute? What the work done by the hand of man, as the burnings of heath and the like for the cultivation of land; the burnings of corn and villages in wars; the draining of marshes; the perpetual discharges of cannon; and the ringing of bells in great cities? Such matters indeed appear trivial, but yet they have some influence.
15. Inquire into all the methods of exciting or calming the winds, but less fully into such as are fabulous or superstitious.
From this let the inquiry pass on to the limits of the winds in point of height, extension, and duration.
16. Inquire carefully into the height or elevation of the The Limits of winds, and if there be any mountain tops where
Winds.they do not blow; or if the clouds sometimes appear motionless and stationary, at the same time that the winds are blowing strong on the earth.
17. Inquire carefully touching the space which winds have been known to occupy at the same time, and what are the boundaries of them. For instance, if a south wind is blowing in such a place, will a north wind be blowing at the same time ten miles distant from thence ? On the other hand, in how small a compass can winds be confined, so that (as is the case in some whirlwinds) they appear to run in channels.
18. Inquire touching the greatest, mean, or shortest time, that the winds are wont to continue before they slacken and as it were expire; what again is their usual manner of rising and commencing, what of falling and ceasing ? whether it be sudden, or gradual, or how ?
From the limits of the winds let the inquiry pass on to their successions, either among themselves, or with respect to rain and showers. For as they perform a dance, it would be pleasant to know the order of it.
19. Is there any rule or any observation which can be at all The Successions relied on for the succession of the winds with one of Winds. Is it in conformity with the motion of the sun or not? If there is a rule, what is the nature of it?
20. Inquire into the succession and alternation of the winds and rain ; for the common and familiar idea is that rain calms the winds, and winds keep off and disperse the rain.
21. Is the same succession of the winds repeated after a certain period of years ? if so, what is that period ?
From the successions of the winds let the inquiry pass on to their motions. These motions involve seven inquiries; whereof three are contained in the former articles, the other four remain untouched. For I have already inquired of the motion of the winds as distributed according to the different points of the compass; of the three lines of motion, upwards, downwards, and sideways; and of the accidental motion of compressions. There remain therefore, the motion of progression, the motion of undulation, the motion of conflict, and the motion in organs and machines of human invention.
22. Since progression always begins from a certain point, Different inquire as diligently as possible into the place of the Motions of Winds. first rising, and as it were the fountains of the winds.
For winds appear to resemble Fame; which though they penetrate and bluster everywhere, yet hide their heads in the clouds.' Inquire likewise into the progression itself. For instance, if a . strong north wind blew on such a day or such an hour at York, did it blow two days afterwards in London?
(Virg. AEn. iv. l 7 3.)
23. Omit not to inquire into the undulation of the winds. By undulation I mean that motion by which the wind, like the waves of the sea, is increased or slackened for short intervals; the alternations whereof are best perceived by listening in buildings. But the differences between the undulations or fur. rowings of air and water should be the more carefully marked, because in the air and winds there is no motion of gravity, which is a great part of the undulation in water.
24. Inquire carefully into the conflict and concurrence of winds blowing at the same time. First whether many original winds (not reverberating) can blow at the same time ? And if so, what channels they form in their motion, and what condensations and alterations they engender in the body of the air.
25. Do some winds blow above at the same time that others blow below? For some have observed that the clouds sometimes move in a contrary direction to the weathercock; and likewise are sometimes driven by a strong breeze, when it is quite calm below.
26. Describe very carefully and particularly the motion of the winds in the sailing of ships.
27. Describe the motion of the winds in the sails of windmills, in the flight of hawks and birds, and even in playthings and common matters, as in the waving of banners, the flying of kites, and games which depend on the wind.
FROM the motions of the winds let the inquiry pass on to their force and powers.
28. What are the powers and actions of the winds on
The Powers of Wind & tides and currents, as to keeping them back, driving them on, and causing them to overflow?
29. What are their powers over plants and insects, with regard to bringing locusts, caterpillars, blights, and mildews ?
30. What have they to do with purifying and infecting the air, with regard to pestilences, epidemics, and affections of animals?
31. What is their power of conveying what are termed spiritual species, that is, sounds, radiations, and the like Y
From the powers of winds let the inquiry pass on to their prognostics, not only on account of the use of predictions, but because they lead the way to causes. For prognostics show either the preparations of things before they are produced into action, or their commencements before they are perceptible to the sense.
32. Diligently collect all kinds of prognostics of winds (except those of an astrological nature, the proper inquiry whereof has already been marked out), whether they be sought from the sky, waters, the instinct of animals, or any other source.
LASTLY, conclude the inquiry by investigating the imitations of winds in things natural or artificial.
33. Inquire into the imitations of winds in natural bodies, Imit, p~ °f as flatulency in the bodies of animals, explosions in the receivers of stills, and the like.
Inquire into draughts and artificial winds, as bellows, ventilators in rooms, &c.
Such then are the articles of inquiry. Some of them, I am well aware, it is beyond the power of our present experience to answer. But as in civil trials a good lawyer knows how to put questions suitable to the case, but knows not what the witnesses can answer; so is it with us in Natural History. Let posterity look to the rest.
THE HISTORY. The Names of Winds.
With reference For the sake of clearness and to assist
Article of Inquiry. memory, we give a new set of names to the winds according to their order and degrees, instead of using the old proper names. But since I have borrowed many terms (though not without careful sifting) from the opinions of the ancients, and things will hardly be recognized except under the ancient names, these likewise are annexed to the winds. Let the general division of the winds be as follows: Cardinal Winds, which blow from the cardinal points of heaven; Semicardinal, which blow half way between those points; and Median, which blow intermediate between these again. And of these Median winds let those be called the Greater Medians which blow half way between the Cardinal and Semi-cardinal, and the rest the Lesser Medians.
The particular division of the winds is shown in the following table:
North: East: South: West:
anciently called Boreas. anciently called Eurus or Subsolanua. East and South. anciently called Anster or Not- South anciently called Zephyrus or Favonius. North. west and North and by East. by and by West. by 'a North-North-East: East-South-East: South-South-West: West-North-West: H. d anciently called Aquila, anciently called Vultur- anciently called Libe- anciently called Corus North-East and by nus, South- notus. d South- North-West and by North: East stand by Southest ~ West.
anciently called Meses.
North-East: South-Fast: South-West: North-West:
North -East and by South-East and by anciently =lied Libs. North-West and by I East. South. South-West and by North: West. anciently called Thrascias.
East-North-East: South-South-East: West-South-West: North-North-West:
H &j anciently called Caecias. anciently called oho'- anciently called Atri- anciently called Cirrc nicias. cus. cias.
East anti by North. South and by East. West and by South. North and by -Pest.
There are also other ancient names for winds, as Apeliotes the East wind, Argestes the West-North-West, Olympias anti Scyron the North-West; Hellespontius the East-North-East, and Iapyx the West-North-West; but I do not dwell upon them. Let it be enough to have given fixed names to the winds, according to the order and division of the quarters of the heaven. In the interpretation of authors I place no great confidence; for they are themselves of but little weight.
to the 6th article
There is not a region of the heaven from whence the winds doth not blow.
Article of Inquiry. may not blow. Nay, if the heavens were divided into as many parts as there are degrees in the hori zon, winds will be found at some times or places blowing for each of them.
2. There are whole countries in which it never rains, or at all events very seldom; but there are no countries where it does not blow, and that often.
With reference The phenomena with respect to the general winds to the 2nd Article of Inquiry.- are few in number; and no wonder, for these winds principally occur in the tropics, regions considered fatal by the ancients.
1. Persons sailing in the open sea between the tropics are aware of a steady and continual wind (called by the sailors Brize) blowing from East to West. This wind is so strong, that partly by its own blast, and partly by its influence on the current, it prevents vessels sailing to Peru from returning by the same way.1
2. In the European seas, when the sky is calm and clear, and no particular winds are stirring, there is a gentle breeze from the East, following the sun.
3. It is generally observed that the higher clouds move mostly from East to West; and this even at the same time that there is a calm or a contrary wind below. If this is not always the case, the reason may be that particular winds sometimes blow high up, which overpower this general wind.
Admonition. If there be any such general wind following the motion of the heaven, it is not strong enough to resist particular winds. Such a wind is more observable in the tropics, because it moves there in larger circles; and also in the higher regions of the air for the same reason, and because it has there a free course. Wherefore if you would discover it outside the tropics, and near the earth (where it is very gentle and inactive), make the experiment in the open air, in a perfect calm, on high ground, with a body very susceptible of motion, and towards evening; because at that the time particular east wind does not blow so much.
Injunction. Observe carefully whether the weathercocks and vanes on the tops of towers and steeples do not in the most perfect calms point steadily to the west.
4. It is certain that in Europe the east wind is sharp and Indirect drying, the west wind moist and genial. Is not this phenomena because (assuming that the air moves from east to west) the east wind, which moves in the same direction, must rarify and dissipate the air; and so make it dry and biting.; whereas the west wind which moves in a contrary direction collects and condenses the air; which thereby becomes less keen, and in the end wet?
5. Consult the inquiry into the motion of the tides, as =to whether they move from east to west. For if the heaven and the waters which are the extremes prefer this motion, it is not unlikely that the air which lies between them will likewise partake of it.
Admonition. These two phenomena last mentioned are termed indirect, because they exhibit the matter in question not directly, but by consequence: a kind of evidence which (in the absence of direct phenomena) I eagerly receive.
Injunction. That this Brize blows perceptibly in the tropics is a certain fact, but the cause of it is doubtful. It may be that it is because the air moves as the heavens do; only that outside the tropics the motion is almost imperceptible by reason of the smaller circles, whereas it is manifest within them where the circles are larger. Or it may be that as all air is expanded by heat, and can no longer be contained in the same space, the contiguous air is necessarily impelled by the expansion, and produces this brize as the sun. advances. But within the tropics, where the sun has greater power, this is more remarkable; without them, it is hardly perceptible. By way of a Crucial Instance to decide the point, inquire whether the brize blows at night or not. For the rotation of the air continues by night, but the heat of the sun does not 6. But it is certain that this brize does not blow in the night, but that it blows in the morning. and even some time after sunrise. Nevertheless this does not terminate the inquiry. For the nocturnal condensation of the air, especially in those countries where the days and nights are not more equal in their lengths than they are different in their degrees of heat and cold, may weaken and disturb this natural but feeble motion of the air.
7. If the air participates in the motion of the heaven, it follows, not only that the east wind is concurrent with the motion of the air, and the west wind is opposed thereto; but also that the north wind blows as it were from above and the south wind as it were from below in our hemisphere, where-the north pole is raised above the earth and the south depressed below it. And this has even been remarked by the ancient:, though with hesitation and obscurity; but it agrees well with modern experience; because this brize (which may be a motion of the air) is not due east, but north-east.
reference to As in the inquiry touching the General winds of men have been afflicted with blindness, so in that
Transition. of the Periodical winds, they have suffered dizziness and confusion. Of the former they say nothing, of the latter they talk vaguely and incoherently. But this is the more pardonable, because the thing is variable. For periodical winds change with the place, and the same do not blow in Egypt, Greece, and Italy.
1. That there are periodical winds in some places the application of the name declares, as well as that other appellation of Etesian or Anniversary winds.
2. It has been set down by the ancients as one of the causes of the inundation of the Nile, that at that time of the year the Etesian or North winds are prevalent, which prevent the river from running into the sea, and drive it back.'
3. There are currents in the sea, which can neither be attributed to the natural motion of the ocean, nor to a descent from higher ground, nor to the narrowness of channels, nor to promontories jutting out into the sea; but which are plainly influenced by periodical winds.
4. Those who are unwilling to admit that Columbus conceived so certain and fixed an opinion of the West Indies from the narrative of a Spanish pilot, and consider it still more unlikely that he derived it from the obscure vestiges and rumours of antiquity, take refuge in this; that from periodical winds blowing to the coast of Portugal, he imagined that there was a continent to the westward. The circumstance is doubtful and not very probable, since the winds could hardly travel so great a distance; but in the meantime it is a great honour to this inquiry, if the discovery of the new world may be attributed to one out of the many axioms or observations that it contains.
5. Wherever there are high mountains covered with snow, periodical winds blow from that quarter at the time of the melting of the snows.
(i Herod. ti. 20., and Pliny, v. 10.)
6. I judge also that from large marshes, which in winter time are entirely flooded, there blow periodical winds at the time when the heat of the sun commences to dry them; but of this I have no certain information.
7. Wherever there is a plentiful generation of vapours, and that at certain times, you may be sure that at those times periodical winds will arise there.
8. If periodical winds are blowing anywhere, and there be no cause for them to be discovered near at hand, you may know that such periodical winds are strangers and come from a distance.
9. It has been remarked that periodical winds do not blow at night, but get up the thud hour after sunrise. They appear indeed like winds tired with a long journey, so as to be scarce able to break through the condensation of the night air, but after sunrise they are roused up for a while and continue on their course.
10. All periodical winds (except they rise near at hand) are weak, and easily overpowered by winds that rise suddenly.
11. There are many periodical winds which are neither perceived nor observed, by reason of their weakness and their being overpowered by the free winds. In the winter time therefore, when the free winds are most prevalent, they are scarce perceptible; but in the summer, when these wandering winds are less frequent, they are more apparent.
12. In Europe the principal periodical winds are, northerly winds from the solstice, both before and after the rising of the dog star; west winds from the autumnal equinox; and east winds from the vernal equinox'; for the winter solstice deserves less attention by reason of the frequent changes in winter.
13. The Ornithian or Bird-winds (so called because they bring birds from cold regions beyond the sea to more sunny climes) have nothing to do with periodical winds; for they often fail in point of time. But whether they blow late or early, the birds wait for their convoy; and if, as often happens, the winds commence to blow and then change again, the birds being deprived of their help drop into the sea, and sometimes fall upon ships.
14. The precise day or hour of the return of the winds is not discovered as it is in the tides. Some writers sometimes specify a day, but it is rather by conjecture than constant observation.
(1 Pliny, i9. 47, 48.)
With reference This term of Attendant Winds is my own; and to the Ch and 5th
Articles of Inquiry. I have invented it lest the observation of them be Transition. forgotten or confused. My meaning is this. Take any country and divide the year into three, four, or five parts. If any wind blows there for two, three, or four of these parts, and a contrary wind for only one part, the wind which blows oftenest is called the attendant wind of that country. And the same is the case with respect to the weather.
1. The south and north winds are the attendant winds of the world; for they with their divisions blow more frequently over the world than the east or west winds with their divisions.
2. All free winds (not periodical) are attendants of the winter rather than the summer, but principally of the autumn and spring.
3. All free winds attend more upon the regions without the tropics, and even the polar circles, than those within them; in the torrid and frigid zones they blow more seldom, in the temperate more frequently.
4. All free winds likewise, and especially the strongest of them, blow oftener and more violently in the morning and evening than at noon and night.
5. Free winds are more general in lands full of holes and ca-vities than on solid and firm soils.
Injunction. Human care has been very remiss in the, obser-vation of attendant winds in particular districts; vet such observation, if it were made, would be useful in many respects. I remember that an intelligent merchant who had carried out a colony to Newfoundland and passed the winter there, told me, when I asked him why that country was reputed so extremely cold where the latitude was sufficiently mild, °° that it was not quite so bad as was reported, but that the reasons were two: the one, that icebergs were brought down by the current of the Arctic Sea close beside those shores; the other " (which he considered the more important), °° that the west wind blows there for a much greater part of the year than the east; which is likewise the case (said he) in England; but then in Newfoundland it blows cold from the continent, here it comes warm from the sea. Now if," he continued, °° the east wind blew as long and as frequently in England as the west wind blows in Newfoundland, the cold here would be far more intense, and equal to what it is there."
6. The west wind is the attendant of the afternoon, for it blows more frequently than the east wind when the sun is declining
7. The south wind is the attendant of the night, for it rises oftener in the night, and blows stronger. The north wind blows in the daytime.
8. There are many great differences between the attendant winds of the sea and those of the land. The chief one is that which suggested to Columbus the discovery of the New World; namely, that sea winds are not periodical as land winds generally are. For since the sea abounds with vapours, which are present everywhere almost indifferently, winds likewise are generated everywhere, and having no fixed origins and birthplaces blow every way with great uncertainty. But the land is very unequally provided with the matter of winds; some places being well supplied with the means of generating and increasing them, others comparatively deficient. And therefore they commonly blow from their nurseries, and take their direction. accordingly.
9. Acosta does not appear to be very consistent, when he says in one place that south winds blow during almost the whole year in Peru and along the coasts of the South Sea, and in another that sea-Winds generally blow there.' For the south wind there is a land wind, as also is every. other wind except the west. We may adopt however what he observes as more certain, namely, that the south wind is the attendant and common wind of those countries; unless perchance his imagination or manner of speaking were betrayed into error by the name of the South Sea; and he takes the west wind, because it blows from the South Sea, for the south. For the sea termed the South Sea is not properly the South Sea, but as it were a second Western Ocean; for it stretches in the same direction as the Atlantic.
10. Sea winds are doubtless moister than land winds, but yet purer, and more easily and equally mixed with pure- air. For land winds are compounded of deleterious mixtures; and are full of smoke. And let no one oppose to this, that sea winds must be heavier by reason of the. saltness of the sea; for salt being in its nature terrestrial does not rise in vapours.
I Acosta, Hist des Index, iii. 20., and ii. 13.
11. Sea winds are warm or cold, according as they are moist or pure. Cold is lessened by humidity (for dryness intensifies both heat and cold), but increased by purity. Therefore these winds are warm outside the tropics, but cool within them.
12. 1 judge that sea winds are the attendant winds of all countries, especially on the coast. For winds from the sea are much more common, by reason of the far greater abundance of matter for winds at sea than on land; unless perchance from some peculiar cause there happen to be a periodical wind blowing from the land. But let no one confuse periodical and attendant winds together; for the latter blow much more generally than the former. They have however this in common, that they blow from the quarter where they are bred.
13. Sea winds are generally more violent than land winds; yet when they subside the calm is greater out at sea than near shore; so that sailors sometimes prefer rather to coast along the shore than to venture out to sea, lest they should be becalmed.
14. There blow from the sea to the shore winds which are intermittent; that is, winds which advance a little way, and then suddenly turn back. This surely is caused by a kind of refraction and inequality between the breezes of the sea and of the land; for all inequality of the air is a commencement of wind. Such intermittent and eddying winds are most frequent in bays and arms of the sea.
15. Some breezes generally blow about all great waters, and are mostly perceptible in the morning; but they appear more about rivers than at sea, by reason of the difference between the breeze from the land and from the water.
16. Trees growing near the sea usually bend and curve themselves away from the sea breezes, as if they had an antipathy thereto. Not however that these winds have any deleterious quality, but their moistness and density render them as it were heavier.
The Qualities and Powers of 13 ands.
The qualities and powers of the winds have not
27th h. 28th, 29th, been observed diligently and variously. I will tote, and 31st Articles of Inquiry. extract the more certain of thems and leave the
Transition. rest as frivolous to the winds themselves.
1. The south wind with us is rainy, the north wind clear; the former collects and nurtures clouds, the latter breaks and dissipates them. Poets therefore in their descriptions of the deluge represent the north wind as at that time imprisoned, and the south wind let loose with full powers.
2. The west wind is reputed by us as the wind of the Golden Age, the companion of perpetual spring, and the nurse of flowers.
3. The school of Paracelsus, seeking a place for its three principles even in the temple of Juno, that is the air, established three winds. For the east they found no place.
Tincturis liquidum qui mercurialibus Austrum, Divitis et Zephyri rorantes sulphure venas, Et Boream tristi rigidum sale.'
4. In Britain the east wind is considered injurious, insomuch that there is a proverb,°° When the wind is in the east,
'Tis neither good for man nor beast."
5. In our hemisphere the south wind blows from the quarter where the sun is, the north wind from the quarter where it is not. The east wind everywhere follows the motion of the air, the west wind opposes it. In most parts of Europe and Western Asia the west wind blows from the sea, the east from the land. These are the most radical differences of the winds, whereon most of their qualities and powers really depend.
6. The south wind is leas anniversary and periodical than the north wind, but more variable and free z ; and when it is periodical it is so gentle as to be scarce perceptible.
7. The south wind blows lower and more laterally; the north wind higher and more from above. And this is not in consequence of the polar elevation and depression mentioned above, but because the south wind in general has its birthplace nearer the earth than the north wind.
8. The south wind with us is wet (as has been observed before); but in Africa it is fair and brings great heats, and is not cold, as some have afflrmed.3 In Africa it is tolerably
I Johannes Pratensis: Clear Auster with mercurial tinct imbued, Rich Zephyr dewed with sulphur, Boreas drear Rigid with salt.
2 Arlstot. Problem. § De Venti,, 2. ' Id. lb. 51.
healthy, but here if a clear and dry south wind continue long, it is very pestilential.
9. The south and west winds do not generate vapours, but as they blow from quarters where the greatest quantity of vapours is drawn forth by the intensity of the sun's heat, they are rainy. If however they proceed from dry places that are free from vapours, they are fair, sometimes pure, and sometimes sultry.
10. The south and west winds with us seem to be allied, being both warm and moist; and on the other hand the north and east are related, being both cold and dry.
11. The north and south winds (as has been observed before) are more frequent than the east and west; because by reason of the presence and absence of the sun in those parts there is a vast inequality of vapours; whereas in the east and west the sun is as it were indifferent.'
12. The south wind from the sea is very healthy, but more unwholesome from the land. With the north wind the contrary holds good. The south wind from the sea is likewise very beneficial to fruits and plants, driving away blights and other noxious diseases.2
13. The south wind when gentle is not a great collecter of clouds, but it is often clear, especially if it be of short continuance. But if it lasts or becomes violent, it makes the sky cloudy and brings on rain; which comes on rather when the wind ceases or begins to die away, than when it commences or is at its height.
14. When the south wind either rises or falls, there is generally a change of weather, from fair to cloudy, or from hot to cold, and vice versa. But the north wind often both rises and falls, without any change in the weather.
15. After frosts and long snows the south is almost the only wind which blows 3, as if the frozen matter had been digested and so thawed. And yet it is not always followed by rain, but the same thing occurs likewise in fair thaws.
16. The south wind rises oftener and blows stronger by night than by day, especially in winter nights. The north wind, if it should rise by night (which is unusual), hardly ever lasts beyond three days.'
Arlstot. Problem. § De Vends, 37. 2 Id. ib. 19.
' Id. lb. 3. 4 Id. ib. 9. 15.
17. The south wind raises greater waves than the north, even though it blow with equal or less force.
18. In a south wind the sea appears more blue and clear; in a north wind blacker and darker.'
19. A sudden increase of the temperature of the air sometimes denotes rain; and again a sudden change to cold sometimes forebodes the same thing. But this depends upon the nature of the winds; for if it turn warmer with a south or east wind rain is at band; and so likewise if it become colder with a north or west wind.
20. The south wind generally blows solitary and unresisted; but the north winds, especially Cxcias and Corns, are often accompanied by other different and contrary winds, which repel them and make them tumultuous.
21. Take care not to sow in a north wind, or to graft and inoculate when the wind is in the south .E
22. The leaves of trees fall sooner on the south side; but vine shoots burst out on that side, and have scarce any other aspect.3
23. Pliny observes that in large pastures shepherds should take care to drive their flocks to the north side, that they may feed opposite to the south. For if they feed opposite the north, they get foot-rot, scouring, and blear eyes.' The north wind likewise impairs their generative powers, so that if they look against the north wind as they copulate, they mostly produce ewe-lambs. But in this Pliny (as being a transcriber) is, not consistent.-5
24. Winds are injurious to the corn crops at three seasons; namely, on the opening of the flower, on the shedding of the flower, and near the time of ripening. At the two former times they either bind the flower in the stalk or shake it off; at the latter they empty the ear and scatter the grain.6
25. In a south wind the breath of men is more offensive, the appetite of animals is more depressed, pestilential diseases are more frequent, catarrhs common, and men are more dull and heavy; whereas in a north wind they are brisker, healthier, and have a better appetite.? The north wind however is bad for consumption, cough, the gout, or any sharp humour.
Aristot. Problem. § De Vends, 39. 2 Pliny, xviii. c. 33, 34.
Pliny, xviii. 33. 4 Pliny, ubi supra. s Cf. Pliny, viii. 72.
1 Pliny, xviii. 17. 7 Aristot. Problem. § De Ventis, 18. 44, 45.
26. The cast wind is dry, biting, and destructive; the west damp, mild, and genial.
27. The east wind towards the end of spring is destructive to fruits, by bringing in worms and caterpillars which devour almost all the leaves; and it is likewise unfavourable to corn. The west wind on the contrary is very favourable and friendly to plants, flowers, and all vegetation. About the autumnal equinox however the east wind also is tolerably pleasant.
28. The west winds are more violent than the east, and do more bend and wrench trees.
29. Wet weather with an east wind continues longer than with a west, and generally lasts a whole day.
30. The east and north winds when they have once begun are more continuous; the south and west winds are more variable.
31. In an east wind all visible things appear larger 1 ; in a west wind all sounds axe more audible and travel farther.
32. 1° That the wind Caecias attracts clouds,"' passed into a proverb among the Greeks; in comparing it to usurers who draw in money by putting it out. It is a strong wind, but so wide spreading that it cannot drive away the clouds as quickly as they return and resist it. And this appears likewise in the larger conflagrations which make head against the winds.
33. The Cardinal or even the Semi-cardinal winds are not so stormy as the Median.
34. The Median winds from east to north-east are calmer; from north-east to east they are more stormy. So likewise the winds from east to south-east are calmer than from south-east to south; and similarly from south to south-west they are calmer than from south-west to west; and from west to northwest they are calmer than from north-west to north. So that proceeding in the order of the heavens the Median winds of the first Semi-cardinal are disposed to be calm, those of the latter to be stormy.
35. Thunder, lightning, and tornadoes, occur with cold northerly winds, as the winds Corns, Thrascias, Circias, Meses, Caecias; whence thunder is often accompanied with hail.
36. Snowy winds likewise come from the north, but from those Median winds which are not stormy, as Corus and Meses.
37. Winds in general obtain their natures and properties in
(Aristot Problem. § De Ventis, 55. Id. ib. 1. and 32. ; Cf. Erasm. Adag., i.'5. 62.)
five different ways; namely, from the absence or presence of the sun; from an agreement or disagreement with the natural motion of the air; from the difference of the matter of the nurseries from which they are generated, as sea, snow, marshes, and the like; from the impregnation of the countries through which they pass; or from their local origins, whether on high, under the earth, or in the middle region; all which will be better explained in the ensuing articles.
38. All winds have a power of drying, even more than the sun itself. For the sun draws forth vapours, but does not disperse them, unless it be very powerful; whereas the wind both draws them out and carries them off.' But the south wind does this much less than the others; and stones and beams will sweat even more with a slight south wind than in a calm.
39. March winds are far more drying than summer winds; so that musical instrument makers will wait for March winds to dry the material of their instruments, and make it porous and musical.
40. All winds clear the air and free it from corruption, so that those are the healthiest years in which there is most wind.
41. The sun has a fortune like to that of kings, whose governors in distant provinces have more submission and obedience from their subjects than is paid to the prince himself. For winds, which derive their power and origin from the sun, have certainly equal if not more influence on the temperatures of countries and the dispositions of the air, than the sun itself. And hence it is that Peru (which from lying near the sea and having vast rivers and immense snow-mountains is copiously supplied with winds and breezes) may vie with Europe in the mild and temperate nature of the air
42. We should not be surprised at the winds having so great a force, since strong winds are like inundations and torrents and vast waves of the air. Not however that they have any very extraordinary power after all, if the matter be better examined. They, may blow down trees whose tops being spread like sails help them with the pressure of their own weight. They may likewise overturn edifices that are weakly built, but the more solid structures they cannot destroy, unless accompanied by earthquakes. Sometimes they hurl down avalanchesfrom the mountains, so as almost to bury the plains below them; a thing which befel Solyman in the plains of Sultania.1 Sometimes again they cause great inundations of water.
I Aristot. Problem. § De Ventis, 31. 2 Acosta, Hist. des Indes, 11. 9
43. Winds sometimes dry up rivers, and disclose their beds. For if after a long drought there is a strong wind down stream which continues for some days, so that the fresh water is as it were swept off into the sea, and the tide is prevented from coming up, the river becomes dry in many unusual places.
Admonitions. 1. If you change the poles, you must also change your observations as to north and south. For the absence or presence of the sun is the cause, and this varies according to the position of the poles. But this may always be regarded as certain; namely, that there is more sea to the south and more land to the north, which likewise has no slight influence upon the winds.
2. Winds are generated in a thousand ways, as will be made evident in the ensuing inquiry; whence it is no easy matter to fig observations on so variable a subject Those however which are here laid down may generally be held for certain.
The Local Origins of Winds.
The knowledge of the local origins of the winds to the 8th Article of Inquiry. is a difficult inquiry; for whence the wind cometh Transition. and whither it goeth is regarded even in Scripture as a mystery. And I am not now speaking of the sources of particular winds (of which hereafter), but of the places in which winds in general are bred. Some seek for them on high, others search the deep, but they scarce look for them in that middle space where they are mostly generated. And in this they follow the manner of men to overlook what lies before their feet, and to prefer things dark and obscure. This indeed is certain, that winds are either natives or strangers; for they are as it were trailers in vapours, which they collect into clouds for importation or exportation to and from different countries, receiving winds in return by way of exchange. But let us now inquire concerning native winds; for those which are strangers in one place are natives in another. Winds therefore have three local origins; that is, they either breathe and spring forth fromthe earth, or they are driven down from above, or they are stirred up here in the body of the air. Those driven down from above are generated in two ways; for they are either driven down before they are formed into clouds, or afterwards when the clouds have been rarified and dispersed. Let us now observe what is their history.
1 Knolles' History of the Turks (1603).
1. The poets have feigned that the kingdom of Rolus was situated in subterranean dens and caverns, where the winds were imprisoned, and whence they were occasionally let loose.'
2. Some theologians also, who were likewise philosophers, have drawn a -similar inference from the words of Scripture,
Who brings forth the winds out of his treasures; " as if the winds proceeded from some subterranean treasure-houses or magazines. But there is nothing in this; for Scripture speaks likewise of the treasures of snow and rain, which no one doubts are generated above.
3. There is doubtless a large quantity of air contained in the earth, which probably exhales by degrees, and must certainly from particular causes sometimes rush out in a body.
An indirect Phenomenon. In great droughts and in the middle of summer, when the earth is more full of cracks, great bodies of water are observed to burst forth in dry and sandy places. And if water (which is a gross body) does this seldom; air (which is a thin and rarified body) will probably do it oftener.
4. When air exhales from the earth gradually and at different spots, it is at first hardly perceptible; but when many of these small emanations of air are collected together, a wind is formed from them, as a river from many springs. But this seems to be true; for the ancients have remarked that many winds at their rise and in the places whence they rise are weak at first, but gather strength as they proceed, like rivers.'
5. There are some places in the sea, and likewise some lakes, which without any winds swell exceedingly. This would appear to be owing to some subterraneous blast.
6. It requires a great force of subterraneous air to shake or cleave the earth, but a less to raise the water. Hence it is that earthquakes are uncommon, but swellings and risings of the waters are more frequent
(I VIM AEn. i. b0., &c. 2 Cf. Gilbert, Physiol. Iv. 2)
7. It is likewise everywhere observed that waters somewhat rise and swell before storms.
8. The thin subterraneous air which escapes at different spots is not perceived on land till it is collected into wind, by reason of the porous nature of the earth. But when it rises from below the waters it is perceived immediately from a certain swelling of the waters, by reason of their continuity.
9. It has been before observed that hollow and cavernous districts have their attendant winds; so that these would certainly appear to have their local origins from the earth.
10. On large rocky mountains the winds are found to blow both sooner (that is, before they are perceptible in the vallics), and more frequently (that is when there is a calm in the vallies); but all mountains and rocks are cavernous.
11. Gilbert observes that in Derbyshire I in England, a mountainous and rocky district, there and such strong eruption of winds from some caverns, that articles of dress or rags thrown into them are blown back again with great violence, and carried up a great height into the air.
12. At Aber Barry on the Severn in Wales, there is a rocky cliff filled with holes, to which if a man apply his ear he will hear various sounds and murmurs of subterranean blasts.
Indirect Phe Acosta has observed with respect to the towns of nomenon.
Plata and Potosi in Peru, which do not lie :far apart from one another, and are both situated on :high and mountainous ground, so that there is no differencein this point ; that nevertheless the temperature of Potosi is cold and wintry, while that of Plata is mild and spring-like .2 This may perhaps be owing to the silver mines near Potosi ; which proves that there are vents for hot and cold blasts from the earth.
13. If the earth be the original source of cold, as Parmenides maintained (an opinion not to be despised, seeing that cold and density are closely united) 3; it is not less probable that warm exhalations should be thrown up from the central cold of the earth, than that they should be thrown down from the cold of the upper air.
14. It is said by some of the ancients that there are certain wells in Dalmatia and the country of Cyrene, into which if a stone be thrown, storms will soon arise'; as if the stone broke through some covering in a place where the winds were confined.
The Latin has Denbigh; but the true reading Is preserved in Gilbert: Derbiae. Acosta, Hist. des Indes, ii. 13. ' Arist. Metaph. i. 5.
12. Bacon v
Indirect Pheno- men Etna and many other mountains vomit forth on. flames; and it is probable that air may break out in the same way, especially being expanded and set in motion by subterranean heat.
15. Upon earthquakes, certain foreign and noxious winds are observed to blow, both before and after the shock; just as a light smoke is commonly emitted before and after great-conflagrations.
Admonition. Air confined in the earth is forced out by many causes. Sometimes a badly cemented mass of earth falls into a hollow; sometimes the waters ingulf themselves in the earth; sometimes the air is expanded by subterranean fires and. requires greater space; sometimes the earth, which was before firm and vaulted, is reduced to ashes by internal fire, and being no longer able to support itself falls in. .And there are many other similar causes.
So much then for the inquiry concerning the first local origin of the winds, namely, from under the earth. I come now to the second origin; namely, from on high, or from what is called the middle region of the air.
Admonition. Let no one misinterpret my words into a denial that the other winds may likewise be generated from vapours both of land and sea. But this I have mentioned is the first kind of winds which spring from the earth as winds ready formed.
16. It has been observed that woods begin to rustle before winds are manifestly perceived 2; whence it is conjectured that wind descends from above. This is likewise remarked on mountains (as I have mentioned before), but the cause is less certain by reason of the hollows therein.
17. The shooting and twinkling of stars foretels wind from that quarter where the shooting is seen 3 ; which shows that the air is disturbed above, before the motion reaches us.
18. The clearing of the sky and dispersing of the clouds foreshadow winds, before they are felt on the earth; which likewise prove that winds commence above.
Pliny, ii. 44. 2 Ibid. xviii. 86.
I Arist Prob. xxvi. 25. ; and Cf. Pliny, xviii. 80.
19. Before the rising of a wind, the lesser stars are not visible, even on a clear night' ; the air apparently being condensed, and made less transparent by the matter which is afterwards turned into winds.
20. Halos round the moon, a blood-red sunset, a red moon on her fourth rising, and many other prognostics of winds derived from above (whereof I will treat in their proper place), indicate that the matter of winds is there commenced and prepared.
21. In these phenomena you may remark the difference already mentioned .between the two ways whereby winds are generated above; namely, before and after the collection of vapours into cloud. For the prognostics from halos and the colours of the sun and moon have some cloudy matter; but the shooting and obscuration of the smaller stars take place in a clear sky.
22. When wind proceeds from a formed cloud, the cloud is either totally dissipated and turned into wind; or it is divided partly into rain, and partly into wind; or it is rent asunder, and the wind bursts forth as in a storm.
23. Many indirect phenomena may be observed in nature of the repercussion by cold. Wherefore, since the cold in the middle region of the air is plainly very intense, it is evident that vapours cannot for the most part penetrate those regions, but must be either congealed or hurled back again. And this was the opinion of the ancients, which in this instance is sound.
The third local origin of winds is in the case of those which are generated in the lower air; to which likewise I give the name of swellings or overcharges of the air. It is a thing very common and familiar, but yet hitherto passed over in silence.
Speculation. The generation of those winds which are stirred in the lower air is nothing more mysterious than this. The air newly created from water and rarified and resolved vapours, being united to the former air, can no longer be confined within the same limits as before, but swells and rolls onwards and occupies a larger space. But here we must assume two things. First, that a drop of water turned into air (whatever stories they may tell of the decimal proportion of the elements) requires at least a hundred times more space than before; and secondly, that a little new air in motion, when superadded to the old, stirs and puts the whole in motion. And this may be seen by the draught from a pair of bellows or a crack in the window, which will set the air of the whole room in motion, as the flame of the candles will directly show
1 Pliny, ubi surpa.
24. As dews and mists are generated in the lower air, with-out being turned into clouds or penetrating into the middle region; so it is with many of the winds.
25. There is a continual breeze playing on seas and waters, which is only a slight wind newly generated.
26. The rainbow, which is the lowest of the meteors and generated nearest the earth, when it does not appear entire, but broken and only with the ends visible, is resolved into winds, as much if not more than into rain.
27. It has been observed that in countries which are divided and separated by the interposition of mountains some winds that are common on one side of the range do not reach the other.' This manifestly shows that they are generated below the tops of those mountains.
28. There is an infinite variety of winds, which blow in clear weather, and even in countries where it never rains, that are generated where they blow, without ever having been clouds or reaching to the middle region of the air.
Indirect Phenomena. Any one who knows how easily vapour is resolved into air, how great is the quantity of vapours, and how much greater space a drop of water occupies when turned into air than it did before (as has been mentioned above), and how little compression the air bears, will feel certain that winds must be gene-rated everywhere, from the surface of the earth to the highest parts of the atmosphere. For a large quantity of vapour, when it begins to expand, cannot possibly rise to the middle region of the air without surcharging the air and producing disturbance on the way.
t Gilbert, Phys. iv. 1.
Accidental Generations of Winds.
o the 9th Accidental generations of winds are those which I quiry. do not produce or create an impulsive motion, but
Transition. either excite it by compression, or drive it back by repercussion, or roll and agitate it by curves. And this is effected by external causes, and the position of contiguous bodies.
1. There is more agitation of the air and sensation of winds in places where there are low hills surrounded by vallies with a higher range of hills beyond, than either on mountains or plains.
2. Winds and draughts are felt in towns where there is any wide place with narrow outlets or passages, and at the corners of streets.
3. Ventilation is produced or arises naturally in houses, where there is a thorough draught, the air going in at one side and out at the other. But it is done more effectually, if the air enters from different sides, meets in angles, and has a common outlet at the meeting-place. Arched and circular dining rooms are cooler likewise, because the air which is stirred in them is reflected in all directions. Curved porticoes are better than straight ones; for a wind in a straight line, though it is not confined but has a free outlet, yet does not make the air so unequal, voluminous, and undulatory, as the meeting in angles, the windings about and collections in a round space, and the like.
4. After great storms at sea the accidental wind lasts for a time after the original wind has settled. And this is caused by the collision and percussion of the air from the undulation of the waves.
5. In gardens the wind is commonly found to be repelled by walls, buildings, and mounds; so that one would think it blew in a contrary direction to that in which it really blows.
6. If one side of a country is surrounded by hills, and a wind blow for a long time from the plain to the hills, this wind being repelled by the hills is either condensed into rain, if it be a moist wind, or changed into a contrary wind, which however is of no long continuance.
7. In weathering headlands sailors often experience a change of wind
Extraordinary Winds and .Sudden Gusts.
With reference to the Some writers give opinions and reasons touching
10th Article of Inquiry.
extraordinary winds, as hurricanes or storms, whirl winds, typhoons, and siroccos; but they give no description of the thing itself, which certainly is to be sought from journals and scattered history.
1. Sudden gusts never come in a clear sky, but only when it is cloudy and with rain; so that there is rightly thought to be an eruption, with a discharge of the wind and a concussion of the water.
2. Those storms attended with cloud and fog, called 11 belluae," which rise up like pillars, are very violent and dangerous at sea.
3. The greater typhoons, which extend over some considerable space and carry things up into the air along with them, seldom occur; but the lesser and as it were playful eddies and whirlwinds are common.
4. All storms, typhoons, and greater whirlwinds, have a manifest motion of precipitation or vibration downwards, more than the other winds. And hence they appear to rush like torrents, and to flow down as in channels, and to be then repelled by the earth.
5. It sometimes happens that in meadows haycocks are carried up into the air, and then spread abroad like a cover over the field. Again, bundles of pea-straw, Sheafs of corn, and linen hung out to dry, are lifted as high as the tops of trees or above the tops of houses by whirlwinds; and all this is done without any great force or violence of wind.
6. Sometimes these very slight and partial whirlwinds take place even on a clear day; so that a person riding may see dust or straws caught up and whirled round near him without feeling much wind. Thus is doubtless caused by contrary breezes mutually repelling one another, and making a circulation of air by the concussion.
7. It is certain that there are some blasts which leave behind them on plants manifest traces of burning and scorching. But the sirocco, which is an invisible lightning and a burning air without flame, is referred to the inquiry on lightning.
Things Contributing to Winds, that is, the Original; for of Accidental Winds it has been inquired above.
With reference The ancients have given a very confused and to the 11th uncertain account of the winds and their causes, 12th, 19the 15th A 14th. rticles
of inquiry. and mostly not true. But no wonder that those Transition. who do not look close do not see clearly. Theytalk as if wind were something else, different from air in motion; and as if exhalations generated and composed the whole body of winds; and as if the matter of winds were only a hot and dry exhalation t ; and as if the origin of the motion of winds were only an expulsion and repercussion from the cold of the middle region; all which things are mere arbitrary and imaginary suppositions. But yet from these threads, which are indeed but cobwebs, they weave large webs.
Whereas in reality every impulse of the air is a wind; exhalations mixed with the air contribute more to the motion, than to the matter of the winds; moist vapours are by a well proportioned heat turned into wind more easily than dry exhalations ; and many winds, besides those which are driven down and repelled from above, are generated in the lower region of the air, and exhale from the earth. Let us observe what is the language of the things themselves.
1. I have mentioned in the article on general winds, that the natural rotation of the air, without any other external cause, generates a perceptible wind within the tropics, where the air revolves in larger circles.
2. Next to the natural motion of the air, before inquiring concerning the sun, which is the principal parent of the winds, we must observe whether anything be due to the moon and other stars, upon clear experimental evidence.
3. Great and violent winds arise some hours before an eclipse of the moon; so that if the moon is eclipsed at midnight, there are winds the evening before; but if in the morning, there are winds at midnight.
4. Acosta observes that in Peru, which is a very windy country, there is most wind at the full moon.2
t Arist. Meteorolog. ii. 4. 1 Hist. des Indes, ii. 7.
Injunction. It would be well worth observing, what effect the motions and changes of the moon have upon the winds, for they certainly influence the ,waters. For instance, whether the winds like the tides are not somewhat higher at the full and new moon, than in the quarters. For though it may be a convenient theory, that the moon has dominion over the waters, and the sun and stars over the air; yet it is certain that water and air are very homogeneous bodies, and that-next to the sun, the moon has the greatest power in every, thing here below.
5. Greater winds are observed to blow about the time of. the conjunctions of planets.
6. Winds and stormy weather are frequent at the rising of Orion I ; but we should observe whether this does not proceed from the rising of that constellation at a time of year most generative of winds; so that it would be rather a concomitant than a cause. And a similar doubt might justly be raised respecting the rains at the rising of the Hyades and Pleiades, or the storms at the rising of Arcturus. And so much with regard -to the moon and stars.
7. The sun doubtless is the primary efficient of many winds,, as by its heat it operates upon two kinds of matter; namely, the body of the air, and vapours or exhalations.
8. The sun, when powerful, expands air, though pure and entirely unmixed, perhaps as much as one-third, which is no trifling difference. From this simple expansion therefore some wind must arise in the sun's paths, especially during great heats; and that rather two or three hours after sunrise than at daybreak.
9. In Europe, the nights are more sultry; in. Peru, the three first hours of the morning Z ; both from the same cause, namely, the cessation of winds and breezes at those hours.
10. In a water thermometer dilated air depresses the water as with a blast; but in a glass filled only with air and capped with a bladder the dilatation of the air blows out the bladder perceptibly, like a wind.
11. I made an experiment of this kind of wind in a round tower that was completely shut up on every side. A chafing dish of coals thoroughly ignited so that there might be no smoke was placed in the middle of the room. At one side of this, but at some distance from it, I suspended a thread, with a cross of feathers fastened to it to make it more susceptible of motion. After a short time therefore, when the heat had increased and the air dilated, the cross of feathers with its thread began to wave about, first to one side and then to the other. And further, when a hole was made in the window of the tower, a warm gust of air passed out, not continuous, but intermittent, and in, undulating currents.
(Arlst. Problem. De ventis, 14. 1 Acosta, Hist. des Indes, it. 13)
12. The contraction of the air by cold after it has been dilated likewise creates a wind of the same kind, but weaker, because cold has less force. In Peru therefore under any spot of shade not only is the coolness greater than is felt here (which is the result of antiperistasis), but there is a manifest breeze from the contraction of the air as soon as it comes under the shade.' And so much for wind caused by mere dilatation and contraction of the air.
13. Winds rising from mere motions of the air, with no intermixture of vapours, are soft and gentle. Let us now inquire concerning vaporous winds (or winds generated from vapours), which may be as much stronger than the former, as the expansion of a drop of water turned into air exceeds any expansion of air already made; which it was shown to do many degrees.
14. The sun with its proportionate heat is the efcient of vaporous winds (which are those that commonly blow). The matter is the vapours and exhalations turned and resolved into air; I say air (not anything other than air), though not quite pure to begin with.
15. The sun when it has little heat raises no vapours, and therefore creates no wind.
16. The sun, when it has a moderate heat, draws out vapours, but does not immediately dissipate them. And therefore, if there be a large quantity of them, they collect into rain, either alone, or accompanied with wind. If the quantity be small, they are turned into wind alone.
17. The heat of the sun on its increase is more disposed to generate winds; on its decrease to generate rain.
18. The intense and continued heat of the sun rarifies, disperses, and elevates vapours, and at the same time mixes them equally and incorporates them with the air; which makes the air calm and serene.
(Acosta, ubi supra.)
19. The equal and continuous heat of the sun is less favourable than the unequal and variable heat for the generation of winds. Renee it is that winds are less troublesome in a voyage to Russia than in the English Channel, by reason of the long days. But at the tune of the equinox in Peru, winds are very frequent, by reason of the great inequality of heat between day and night.
20. In vapours both the quantity and quality are of importance. A small quantity produces gentle gales; a moderate quantity strong winds; a large quantity charges the air and generates rain, either with or without winds.
21. Vapours arising from the sea, rivers, and inundations, generate a far greater quantity of winds than do exhalations from the land. But yet winds which arise from the earth, and less damp places, are more fixed and continuous; and these generally are those which are driven down from above. The opinion therefore of the ancients would not have been totally unprofitable in this respect, had they not chosen as it were to divide the inheritance, and to assign rains to the vapours and only exhalations to the winds. And things of this kind sound well in words, but are really worthless and unprofitable.'
22. Winds from the melting of snow on the mountains occupy a middle space between water and land winds, but incline rather to the former, though they are more keen and active.
23. The melting of snow on the snow mountains always, as has been before observed, produces periodical winds from that quarter.
24. The anniversary north winds at the rising of the dog.. star a are supposed to come from the frozen sea, and the regions about the Arctic circle, where the ice and snow are not melted till summer is far advanced.
25. The masses or mountains of ice which are carried down towards Canada and Newfoundland are more generative of cold gales than variable winds.
26. The winds from sandy or chalky soils are few and dry; but in hotter countries the same are sultry, smoky, and burning.
Arist. Meteorolog. ii. 4. CE Pliny,
27. 'Winds generated from sea-vapours more easily return to rain, as the watery element asserts and reclaims its right; but if this does not take place, they mix directly with the air, and remain quiet. But terrestrial, smoky, and unctuous ex-halations are less easily resolved, ascend higher, are more excited in their motion, frequently penetrate into the middle region of the air, and make up some of the matter of fiery meteors.
28. It is reported in England that, when Gascony was under our dominion, the inhabitants of Bordeaux and the neighbour-hood presented a petition to the king, to stop the burning of heather in Sussex and Hampshire; because about the end of April it caused a wind destructive to the vines.
29. The meetings of winds together, if the winds be strong, produce violent whirlwinds; but if the winds be gentle and moist, they cause rain and a calm.
30. Winds are calmed and restrained in five ways; namely, when the air charged and agitated with vapours is freed by the vapours becoming condensed into rain; or when the vapours are rarified and dissipated, and are thus mixed with the air, and agree well with it, and keep quiet; or when vapours or exhalations are raised and exalted so high, that there is a com-plete freedom from them, till they are either driven down from the middle region of the air, or admitted into it; or when vapours collected into clouds are driven by the upper winds into other countries, and so leave the lands over which they pass calm and undisturbed; or lastly, when the winds blowing from their nurseries become feeble by reason of the length of their journey and the want of fresh matter, and losing their force gradually die out.
31. Showers generally allay the winds, especially if they be stormy; as on the other hand winds often keep off rain.
32. Winds contract themselves into rain (which is the first and principal of the five ways in which they are calmed), either when overcharged by the quantity of vapours, or by reason of the contrary motions of gentle winds, or by reason of the op-position of mountains and headlands, which resist the shock of the winds and gradually turn them back on themselves, or by reason of the condensation from intense cold.
33. The smaller and lighter winds generally rise in the morning and f ill at sunset, as the condensation of the night air has power enough to contract them. For the air will submit to some compression without becoming agitated.
34. The sound of bells is supposed to dissipate thunder and lightning; but this has not come under observation with respect to winds.
Admonition. Consult here the passage concerning the prognostics of winds; for there is some connection between causes and signs.
35. Pliny mentions that the violence of a whirlwind is stopped by pouring vinegar upon it.'
The Limits of Winds.
With reference to 1. It is said that the priests who offered the and 18th rticiee yearly sacrifices on the altars at the tops of Mont of Inquiry. Athos and Olympus used to find the letters which they had traced in the ashes of the victims the preceding year no way disarranged or obliterated; and this, although the altars did not stand in a temple, but in the open air.' This fully proved that at that elevation there had been neither rain nor wind.
2. It is said that at the top of the Peak of Teneriffe, and also on the Andes between Peru and Chili, snow lies along the cliffs and sides of the mountains; but at the summits themselves there is nothing except a still air, so rarified as almost to stop respiration, and so acrimonious and pungent as to excite nausea, in the stomach, and to redden and inflame the eyes.'
3. Vaporous winds do not appear to blow at any great elevation, though some of them are probably higher than most clouds.
So much for the height; now for the latitude of the winds.
4. The winds certainly occupy very various spaces; sometimes very extensive, and sometimes very narrow and confined. They have been known to cover a space of 100 miles within a few hours.
5. Free winds that range over a wide space are generally strong and not mild. They last generally for about twentyfour hours, and are not rainy. Confined winds on the other hand are either mild or stormy, but always of short duration.
' Pliny, SL 49. = CL. Arlst. Prob. xxvi. 39. ; and Solinus Polyhist. 15.
s CC Acosta. iil. 9. 20.; and Purchas, v. 785.
6. Periodical winds are itinerant, and fill a very extensive space.
7. Stormy winds do not travel far, though they always spread beyond the limits of the storm itself.
8. Sea winds are much more partial than land winds; so that sometimes at sea a fresh breeze may be observed to be curling and rufing the water in one direction, while everywhere else the sea is as calm and smooth as a mirror.
9. I have before alluded to the small whirlwinds which sometimes play before persons on horseback, almost like the blast from a pair of bellows. I now pass from the latitude to the duration of the winds.
10. Very strong winds continue longest at sea, where there is a plentiful supply of vapours. On land they scarce ever last more than a day and a half.
11. Very gentle winds do not blow continuously for more than three days, either on land or sea.
12. The east wind, as has been elsewhere observed, is of longer duration than the west. And also every wind which springs up in the morning is more lasting than one that rises in the evening.
13. It is certain that winds (unless they are mere storms) rise and increase gradually, but fall more quickly, and sometimes all at once.
The Successions of Winds.
With reference to west, from west to north, from north to east, it does not generally go back; or if it does, it is only for a short time. But if it move contrary to the motion of the sun, that is if it changes from east to north, from north to west, from west to south, from south to east, it generally returns to the former quarter, at least before it has completed the entire circle.
1. If the wind follows the motion of the sun, that the 111th 20th and 21st. Articles is if it move from east to south, from south to of Inquiry.
2. If rain falls before the wind commences, the wind will last longer than the rain. But if the wind blows first and is afterwards laid by rain, it does not often rise again; and if it does, it is followed by fresh rain.
3. If the wind shifts about for a few hours as if it was trying the different points, and then commences to blow constantly from one quarter, that wind will last many days.
4. If a south wind begin to blow for two or three days, a north wind will sometimes rise directly afterwards. But if there has been a north wind for as many days, the wind will blow for a short time from the east before it comes from the south.'
6. Towards the end of the year and the commencement of winter, if the south wind blow first and be succeeded by the north, it will be a severe winter .2 But if the north wind blow at the commencement of winter, and be succeeded by the south, the winter will be mild and warm.
7. Pliny quoting Eudoxus asserts that the same series of winds returns every four years a; which does not appear to be true, for the revolutions are not so rapid. It has been observed by the diligence of some that the greater and more remarkable seasons of weather, as great heats, great snows, great frosts, warm winters, and cold summers, generally come round in a circuit of thirty-five years.
The Motions of Winds.
with reference Men talk as if the wind were a body of itself,
to-'V. the 22nd,
2s. which of its own force drove and impelled- the 25th, 26th, and
26th Articles of inquiry. air before it. And likewise when it changes
Transition. they talk as if the same wind transferred itself to another place. And when the people talk in this way, philosophers prescribe no remedy for such opinions, but they themselves talk confusedly, without opposing these errors.
1. After the inquiry therefore into the local origins of the winds, I come next to that concerning the raising and directing of their motion. In winds which have the commencement of motion in their first impulse, as those which are driven from above, or exhale from the earth, the excitation of motion is manifest. The former descend, the latter ascend at their commencements, and afterwards acquire a winding motion from the resistance of the air, principally according to the angles of their force. But the inquiry concerning the winds which are stirred up everywhere in the lower air, (and are the commonest winds of all,) is more obscure. And yet, as has been observed in the speculation on the eighth article, the thing itself is common and familiar.
(t Arist. Frob. xxvi. 49. 2 Id. ib. 48. 3 Pliny, ii. 48.)
2. There is some resemblance to this thing in that experiment of the close tower which has been described before. For that experiment was varied in three ways. The first was that already mentioned, by means of a chafing dish of ignited and bright coals. The second was by removing the chafing dish, and substituting a kettle of boiling water, which made the motion of the cross of feathers slower and less active than before; as the heat was not strong enough to prevent the dewy vapour of the water from hanging in the air, and could not dissipate it into the matter of wind. The third was by the use of both the chafing dish and the kettle, which most of all agitated the cross of feathers; so that it appeared sometimes to be lifted up as by a small whirlwind. For now there was both the water to supply plenty of vapour, and the chafing dish at hand to dissipate it.
3. From this it appears that the overcharging the air by the resolution of vapour into air is a principal cause of exciting motion in the winds.
I must now pass on to the direction of motion, and its verticity or charge of direction.
4. The direction of the progressive motion of the winds is controlled by the nurseries, which are to winds what fountains are to rivers. Such are places which abound in vapours; for there is the native country, of the winds. Now when they, have found a current, where the air offers no resistance, (as water finds -a declivity,) they unite with all the homogeneous matter they find in their course, and carry it off with them, as rivers do. 'Winds therefore always blow from the quarter where their nurseries lie.
5. When the winds have no special nurseries in any fixed spot, they become exceedingly erratic and easily, change their current; as may, be seen in the middle of the sea and in wide plains.
6. When the winds have great nurseries in one spot, but receive small accessions from the places through which they, journey, they blow strongly at first, but gradually slacken. On the other hand when the nurseries are more continuous, the winds are gentler at first, but afterwards increase.
7. The winds have movable nurseries in the clouds, which are often transported by the upper winds to places far distant from the nurseries of the vapours from which those clouds were generated. But in this case there begins to be a nursery of the wind on that side where the clouds are first turned into wind.
8. The verticity of the winds is not caused by a wind transporting itself while it is blowing, but by its either falling of itself, or being overpowered by another wind. And all this depends on the different situations of the nurseries of winds, and the different times and seasons when the vapours emanating from these nurseries are resolved.
9. If there be nurseries of winds on opposite sides, that is, if one be in the north, the other in the south, the stronger wind will prevail, and will blow continuously without any contrary winds, but somewhat deadened and subdued by the weaker one; in the same way as the force of the tide is affected by the stream of a river; for the motion of the sea does prevail, and becomes the only motion, yet it is somewhat checked by the course of the river. But if the stronger of these two contrary winds happens to fall, the wind will at once spring up from the opposite quarter whence it before blew, though it had been made imperceptible by the power of the stronger.
10. For instance, if there be a nursery of wind in the northeast, the northeast wind will blow. But if there be two nurseries, one to the east, the other to the north, the winds will blow separate for some distance up to the point of confluence:, and then they will set in from the north-east, or with an inclination in the direction of the stronger.
11. If the stronger nursery of wind be to the north, twenty miles distant from any country, and the weaker one be to the east only ten miles off, the east wind will blow for some hours; but soon afterwards the north wind will arrive and supersede it.
12. If the north wind be blowing and fall in with a mountain on the west side, it will soon change to north-east; that is, to a compound of the original and reflected wind.
13. If there be a land nursery of winds to the north,, and the blast from it go straight up, and meet with a cold cloud from the west which drives it to the opposite point, it will blow from the north-east.
Admonition. The nurseries of the winds on sea and land are stationary, so that their birthplace and origin may be better discovered. But the nurseries in the clouds are movable, so that the matter of winds is supplied in one place, while they are formed elsewhere. And this accounts for the direction of motion in the winds being more variable and confused.
These are adduced by way of example; but the like holds in like cases. And so much for the direction of the motion of winds. But we must see further respecting the longitude and as it were the voyage of winds, though this may seem to have been inquired into a little before under the title of latitude. For if winds occupy greater spaces latitudinally than longitudinally, their breadth may be mistaken for their length.
14. If it be true that Columbus on the. coast of Portugal inferred the existence of a continent in America from the periodical westerly winds, winds would certainly appear to travel a very long way.
15. If it be true that the melting of the snows about the Arctic Sea and Scandinavia causes north winds to blow in Italy and Greece during the dog days, that certainly is a great distance.
16. The comparative rapidity with which weather travels in the direction of the different winds has not as yet been observed; for instance, how much quicker a storm comes up from the east with an easterly wind; how much slower from the west.
And so much for the progressive motion of winds; we must now look to their undulation.
17. The undulation of winds is a momentary action; for even a strong wind will rise and fall alternately at least a hundred times in an hour; which shows how unequal the force of the winds is. For neither rivers, though rapid, nor currents at sea, though strong, have any undulation at all, except when the wind blows. And this undulation of the winds has no equality in it, but is like the pulse, sometimes double and sometimes intermittent.
18. The undulation of the air differs from that of the water in this; in water the waves rise, but fall again spontaneously to a level; so that (notwithstanding the lofty expressions of the poets concerning storms, 1° that the waves rise to heaven and sink to hell,") they do not fall much below the level surface of the water. But in the undulation of the air, where there is no motion of gravity, the air is raised and depressed almost equally. And so much for undulation. We must now inquire concerning the motion of conflict.
13 Bacon V
19. I have already partly inquired into the conflicts and compound currents of the winds. It is manifest that winds, especially the milder ones, are ubiquitous; as is likewise proved by the fact that there are few days or hours wherein some gentle breezes do not blow in open places; and that with great irregularity and variety. For the winds which do not proceed from the larger nurseries are erratic and changeable; sometimes propelling and sometimes flying from one another, as if in sport.
20. Two contrary winds are sometimes observed to meet together at sea; as is shown by the ruffling of the surface of the water on both sides, and the stillness between them. After -the collision, if the winds break each other equally, a general calm ensues; but if the stronger wind prevail, the agitation of the water is continued.
21. It is certain that, in Peru winds often blow from one quarter on the mountains, and directly contrary in the vallies.
22. It is likewise certain that with us the clouds move in a direction contrary to the wind here below.
23. Again, the higher clouds are sometimes seen to scud over the lower; so as to pass in different and even contrary directions, as if driven by opposite currents.
24. It is likewise certain that in the upper air the winds sometimes are neither distracted nor impelled, while half a mile below they are driven along in mad fury.
25. Contrariwise also, there is sometimes a calm below when the clouds are moving rapidly above; but this is less common.
Indirect phennomenon In the waves likewise, sometimes the water the top, sometimes that below moves the quickest; and sometimes (though rarely) there are different currents of water, the one above and the other below.
26. We should not altogether neglect the testimony of Virgil, seeing he was by no means ignorant of natural philosophy ; °° At once the winds rush forth, the east, and south, and south-west laden with storms; "1 and again, °° I have seen all the battles of the winds meet together in the air." 2 So far then have I inquired concerning the motions of the winds in nature. I must now look to their motion in machines of human invention ; and above all in the sails of ships.
t Una Eurusque Notusque ruunt, creberque procellis
Africus.-AEn. i. 85.
2 Omnia ventorum concurrere praelia vIdi.-Georg. 1.3
The Motion of Winds in the Sails of Ships.
1. The largest British ships (for I take them as my example) have four and sometimes five masts; all standing erect one behind the other in a straight line drawn through the centre of the vessel.
2. The names of these masts are ; the mainmast in the centre, the foremast, the mizenmast (which is sometimes double), and the bowsprit.
3. Each mast consists of several parts, two or three in number, which may be raised, and by certain knots or joints fixed in their place, and in like manner taken down.
4. The bowsprit from its lower fastening is inclined towards the sea, from its upper fastening it is erect. All the other masts axe perpendicular.
5. These masts are rigged with ten sails, and when the mizenmast is double, with twelve. The mainmast and the foremast have three tiers of sails, which we call the mainsail, the topsail, and the top-gallantsail. The others have only two sails, being without the top-gallantsail.
6. The sails are extended crossways, near the top of each joint of the mast, by pieces of timber which we call yards. To these the upper part of the sail is stitched, while the lower part is tied with ropes at the corners only; and in this fashion the mainsail is attached to the sides of the ship, the topsail and the top-gallantsail to the yards contiguous to them. The same ropes serve to draw or turn them to either side at pleasure.
7. The yard of each mast stretches in a horizontal direction; except that of the mizenmast, which is slanted, with one end elevated and the other depressed. The rest are at right angles to the mast, like the cross of the letter T.
8. The mainsails of the mainmast, foremast, and bowsprit, are of a quadrangular or parallelogram shape; and the top and top-gallantsails are somewhat sharpened and pointed; but in the mizenmast the topsail is pointed and the mainsail triangular. feet wide in the hold, the mainsail of the mainmast was 42 feet deep and 87 feet wide.
9. In a ship of 1100 tons, 112 feet long in the keel., and 4
10. The topsail of the same mast was 50 feet deep, 84 feet wide at the base, and 42 at the top.
11. The top-gallantsail was 27 feet deep, 42 feet wide at the base, and 21 at the top.
12. The mainsail of the foremast was 401 feet deep, and 72. feet wide.
13. The topsail was 46 1/2 feet deep, 69 feet wide at the base, and 36 at the top. .
14. The top-gatlantsail was 24 feet deep, 36 feet wide at the base, and 18 at the top.
15. The mainsail of the mizenmast was, from the upper point of the yard-arm, 51 feet deep, its width where it is joined to the yard-arm was 72 feet, the other part ending in a point.
16. The topsail was 30 feet deep, 57 feet wide at the base, and 30 at the top.
17. If there are two mizenmasts, the sails of the hindmost are about one fifth less than those of the foremost.
18. The mainsail of the bowsprit was 28 1/2 feet deep, and 60 feet in width.
19. The topsail was 25" feet deep, 60 feet wide at the base, and 30 at the top.
20. The proportions of sails and masts vary not only according to the size of the ship, but also according to the various purposes for which they are built, as whether for war, traffic, speed, and the like. But the dimension of the sails is no way-proportioned to the tonnage of the vessel; for a vessel of 500 tons or thereabouts will carry the mainsail of its mainmast only a few square feet. less than that other which was twice the size. And hence it is that small vessels sail much faster than large ones, not only by .reason of their lightness, but by reason of the size of their sails in comparison with the body of the ship; for if this proportion were kept in large vessels the sails would be too large and unmanageable.
21. As every sail is stretched out straight at the top, and only fastened by the corners at the bottom, they must necessarily be all swollen out by the wind; especially towards the bottom where they are slackest.
22. The swell is much greater in the mainsails than in the rest; not only because they are of a parallelogram shape, and the others pointed; but also because the width of the yard-arm so far exceeds the width of the sides of the vessel, to which they are fastened. For this makes them so slack as to present a great hold to the wind; so that in the large vessel here chosen as a model, the swell of the sail inwards in sailing before the wind may be as much as nine or ten feet.
23. From the same cause likewise all sails swollen by the wind become arched at the bottom, so that much of the wind must necessarily miss them. In the above mentioned vessel this arch is almost equal to the stature of a man.
24. The swell in the triangular sail of the mizenmast is necessarily less than in a quadrangular sail; both because it is of a less capacious shape, and because in a quadrangular figure three sides are slack, in a triangular one only two; whence it it is more stiff for the reception of the wind.
25. The nearer the wind's motion approaches to the head of the ship, the more powerful and propellent it becomes; because it comes at a place where the waves are most easily divided, by reason of the sharpness of the bow, but principally because the motion at the head of the vessel draws the ship along, the motion at the stern only pushes her.
26. Ships are better propelled by the motion of the wind in the upper than in the lower tiers of sails; because violent motion is most powerful when furthest removed from the resistance; as is shown in levers and the sails of windmills. But it endangers the sinking or upsetting of the ship, and therefore these sails are sharpened at the point, that they may not catch too much wind; and they are principally used when there is little wind.
27. When the sails are placed in a straight line, one behind the other, if the wind blow straight from behind, the hindmost must needs steal all the wind from those before them; so that if all the sails were spread at once, the force of the wind would be almost entirely spent on the sails of the mainmast, with little help from the mainsail of the bowsprit
28. In a ship sailing straight before the wind, the best and most commodious disposition of the sails is to hoist the two lower sails of the foremast (for there the motion has been stated to be most powerful), and also the topsail of the mainmast. For there will be space enough left below to allow the wind to fill the afore-mentioned sails of the foremast, without any considerable loss.
29. In consequence of this stealing of the wind by one sail from another, a ship will sail faster with a side wind than with a direct one. For with a side wind all the sails may be crowded; because they all turn their sides to one another, without one standing in the way of the other, or stealing the wind from it.
30. With a side wind likewise the sails are stretched tighter against the wind, which somewhat compresses it, and impels it to that part where it ought to blow; whereby it receives some additional strength. The most favourable wind however is that which blows half way between a fore wind and a side one.
31. The mainsail of the bowsprit can scarcely ever be useless ; for, as it collects all the wind that blows everywhere round the sides of the ship and beneath the other sails, it does not suffer from being robbed.
32. In the motion of winds in ships, both impulse and direction are regarded. But direction by the rudder does not much belong to the present inquiry, except so far as it is connected with the motion of winds in the sails.
Transition. As the motion of impulse is greatest at the head, so the motion of direction is greatest at the stern. And therefore the mainsail of the mizenmast contributes most thereto, and supplies an auxiliary power to the rudder.
33. The mariner's compass being divided into thirty-two points, and each semicircle containing sixteen, a vessel may sail straight forward (without tacking, as is usual when the winds are directly contrary), even though of these sixteen points ten are opposite, and only six favourable; but this navigation greatly depends on the mainsail of the mizenmast. For the points of the wind which are contrary to the ship's course, being the stronger and beyond the control of the helm alone, would turn the other sails together with the ship itself into the contrary direction; did not this sail, being tightly stretched, act the other way, and by favouring and strengthening the motion of the helm, turn and bring round the head of the vessel to its right course.
34. All wind in the sails somewhat weighs down and sinks the ship; and this the more, as the wind comes more from above. And this is the reason why in heavy storms they first lower the yards, and furl the topsails; and then, if it is necessary they take down all the rest, cut down the masts themselves, and throw overboard their cargo, guns, &c., to lighten the ship, that she may float and follow the motion of the waves.
35. With a fresh and favourable breeze, a merchant vessel may sail 120 Italian miles in twenty-four hours, by means of this motion of the winds; and some packet boats called caravels, built entirely for speed, will accomplish a still greater distance. When the winds are directly contrary, they have this last but feeble resource to make some way; which is, they proceed sideways, according as the wind will permit, out of their course, and then by an angular movement they bear up again into it; and continuing this mode of progression (which is slower than that of the serpent, for serpents make folds, whereas they make angles), they will perhaps contrive to make 15 miles in twenty-four hours.
1.The motion of winds in the sails of vessels has three principal heads and fountains of impulse, from whence it springs. From these likewise we may derive rules for increasing and strengthening it.
2. The first source is from the quantity of wind received. For no one doubts that much wind contributes more than little; and therefore a quantity of wind must be carefully procured. This we shall do, if like prudent stewards we are economical and guard against robbery. Therefore, as far as possible, take care that no wind is lost, wasted, or stolen.
3. The wind blows either above the ship's sides, or below them as far as the level of the sea. And as provident men are very careful even about the smallest matters (for there is no one who does not care for the larger ones); so we must first observe these lower winds, though indisputably they are less powerful than the higher ones.
4. With regard to the winds that play chiefly about the sides and under the sails of ships, it is clearly the business of the mainsail of the bowsprit, which is bent low and slanting, to catch them, and so prevent any loss or waste of wine. And this is both a help in itself, and yet it- does not hinder the winds which supply the other sails. On this point I do not see how human industry can improve ; unless perhaps the same kind of low sails were to be used as feathers or wings from the centre of the ship; two on each side, when the wind blows straight from behind.
5. With regard to the prevention of robbery of the foresails by the backsails, in sailing straight before the wind (for with a side wind all sails co-operate), I do not see what human care can 'do ; unless it, be to make a kind of ladder of sails; in which the sails of the mizenmast, should hang lowest, those of the mainmast next, and those of the foremast highest. For in this way one sail would not hinder but rather assist. another, bypassing on and transmitting, the wind. Let these observations then suffice for the first fountain of impulse.
6. The second fountain of impulse springs from the .manner in which the wind strikes the sail. For if by reason of the contraction of the wind the blow be sharp and quick, the motion will be greater; but if it be dull and feeble, the motion will be less.
7. And in relation to this, it is: of very great importance that the sails should only have a moderate swell and extension. For if they be stretched tight, they act like a wall to repel the wind; if they be slack, they make the impulse feeble.
8. With regard to this, in some things human industry has acquitted itself well, though rather by accident than by judgment. For in a side wind they draw in as much as possible the part of the sail opposite to the wind; and thereby they drive the wind to that part where it ought to blow. This indeed they do intentionally. But another effect (which perhaps they do not see) is, that the wind is more contracted and makes the impulse sbarper.
9. I do not see what human industry-can add to this part; unless it be to alter the shape of the sails, and make some of them to swell, not spherically but in the shape of a spur or triangle with a yard or pole in the vertical angle; so that the wind may be contracted more to a point and the external air may be cut more powerfully. And this angle in my opinion ought not to be acute, but like a triangle with the vertex cut oil' to make it wide. Nor do I know what advantage there might be in having a sail within a sail; that is, in inserting in the middle of a large sail a kind of purse, not altogether slack of simple canvass, but with ribs of wood, so as to catch the wind in the middle of the sail and draw it to a point.
10. The third fountain of impulse depends on the place where the percussion is made, and is of two kinds. For the impulse is stronger and easier at the fore part of the vessel than at the hinder; and from the upper part of the masts and sails than from the lower.
11. Neither has this escaped the industry of man; for both in sailing before the wind they put the greatest stress on the sails of the foremast, and in calms they do not neglect to spread their top-gallantsails. Nor can I think at present of any further improvement open to human industry in this point; unless it be, in the first case, to put in two or three foremasts, (the centre one upright, the others inclined) with sails hanging forward; and in the second case to broaden the top-gallantsails of the foremast, and make them less pointed than usual. But in both cases there should be great care not to sink the ship too much.
The Motion of Winds in other Machines of Human Invention.
1. There is nothing very intricate in the motion of windmills, but yet it is not generally well demonstrated or explained. The sails stand right opposite the wind that is blowing ; one side however turning more to the wind, and the other gradually inclining and receding from it. The turning or revolving motion always commences on the lower side, that is, the one furthest from the wind. The wind rushing against the machine is compressed by the four sails, and compelled to make a passage through the four openings between them. But this confinement it does not willingly submit to; so that it begins as it were to jog the sides of the sails and turn them round, as children's toys are set in motion and turned by the finger.
2. If the sails were stretched out equally, it would be uncertain which side they would incline, as it is a question which way a stick would fall. As however the side which meets the wind throws off the force of the wind to the lower side, and thence through the vacant intervals; and as the lower side, like the palm of the hand or the sail of a ship, receives the wind, the rotation forthwith commences from that part. But it should be observed that the origin of motion is not from the first impulse which is made in front, but from the lateral impulse, after compression has taken place.
3. I have made several trials and experiments for increasing this motion, both as a token that the cause has been well discovered, and for present use ; contriving imitations of the motion by means of paper sails and the wind from a pair of bellows. Accordingly, to the lower side of the sail I fastened an additional fold, turned away from the wind; that the wind being now directed from the side might have a larger surface to strike against. But this did no good; for the extra fold did not so much assist the percussion of the wind, as it impeded the cutting of the air by the sails. At some distance behind the sails, and the whole breadth of their diameter, I placed obstacles, that the wind being more com-pressed might strike with greater force; but this did more harm than good, as the repercussion deadened the primary mo-tion. Again I made the sails double their former width, to compress the wind more, and make the lateral percussion stronger. This at last was completely successful, for the sails were turned with a much gentler blast, and revolved much faster.
Injunctions. 1. This increase of motion will perhaps be pro-duced more conveniently by eight sails, than by four sails. of double breadth; unless by chance the weight should be so great as to impede the motion. But of this make a trial.
2. The length of the sails likewise contributes to motion. For in rotations a little force toward the circumference is equal to a far greater force towards the centre. But to this there is one drawback: namely, that the longer the sails are, the further are they separated at the top, and the less is the wind compressed. It might perhaps answer to make the sails a little longer, but widening at the top like the blade of an oar. But of this I have made no experiment,
Admonition. If these experiments be put in practice in wind-mills, the whole machine, especially its foundations, should be strengthened. For the more the wind is compressed (though it increase the motion of the sails), yet the more does it shake the whole machine.
4. It is said that in some parts of the world there are chariots moved by the wind. Let this be carefully inquired.
Injunction. Chariots moved by the wind cannot answer, except in open places and plains. Besides, what is to be done if the wind drops? It would be more reasonable to facilitate the motion of waggons and carriages by movable sails which might spare the strength of horses or oxen, than to depend upon the wind alone for creating motion.
Prognostics of Winds.
With reference to The purer art of Divination should be the more the 32nd Article of p p
Inquiry. received and practised, in proportion as it is wont in general to be corrupted by vanity and superstition. Natural Divination is sometimes more certain, sometimes more treacherous, according to the nature of the subject with which it deals. For if the subject be of a constant and regular nature, the prediction is certain; if it be of a variable nature, and compounded as it were of nature and chance, the prediction is uncertain. But yet even in a variable subject, if rules are diligently framed, a prediction will generally hold good, and will not err much from the truth, though it does not hit the exact point of time. Again, some predictions will be certain enough as to the time of fulfilment; namely, such as are taken not from causes, but from the thing itself having already commenced but displaying itself sooner in a favourable and well disposed matter, than in another; as I have mentioned before, in the topics with reference to this thirty-second article. I will now therefore propound the prognostics of winds, introducing along with them some prognostics of rain and fair weather, which could not well be separated from them; though the full inquiry thereof I remit to their own proper titles.
1. If the sun appear concave at its rising, the day will be windy or showery; windy, if the sun be only slightly concave, and showery, if the concavity is deep.
2. The sun pale and (as we call it) watery at its rising denotes rain; if it set pale, wind.
3. If the body of the sun appear blood-red at setting, it forebodes high winds for many days.
4. If the rays of the sun on rising are not yellow, but ruddy, it denotes rain rather than wind. The same likewise holds good of the setting
5. If either on rising or setting the sun's rays appear shortened or contracted, and do not shine out bright, though there are no clouds, it denotes rain rather than wind.
6. If rays precede the sunrise, it is a sign both of wind and rain.
7. If at sunrise the sun emits rays from the clouds, the middle of his disk being concealed therein, it indicates rain, especially if these rays break out downwards, so as to make the sun appear bearded. But if rays strike from the centre, or from different parts of the sun, whilst the outer circle of his disk is covered with clouds, there will be great storms both of wind and rain.
8. If there be a circle round the sun at rising, expect wind from the quarter where the circle first begins to break; -but if the whole circle disperses evenly, there will be fine weather.
9. A white ring round the sun towards sunset portends a slight gate that same night; but if the ring be dark or tawny, there will be a high wind the nest day.
10. Red clouds at sunrise foretel wind; at sunset, a fine day for the morrow.
11. Clouds collected near the sun at sunrise forebode a rough storm that same day; but if they are driven from the east and pass away to the west, it will be fine.
12. If at sunrise the clouds about the sun disperse, some to the north and some to the south, though the sky round the sun itself is clear, it portends wind.
13. The sun setting behind a cloud forebodes rain the next day; but actual rain at sunset is rather a sign of wind. If the clouds appear as if they were drawn towards the sun, it denotes both wind and rain.
14. If at sunrise the clouds do not appear to surround the sun, but to press upon him from above as if they were going to eclipse him, a wind will arise from the quarter on which-the clouds incline. If this take place at noon, the wind will be accompanied by rain.
15. If clouds shall have shut in the sun, the less light there is left and the smaller the sun's orb appears, the more severe will the storm prove. But if the disk of the sun appear double or treble, as if there were two or three suns, the storm will be much more violent, and will last many days.
16. The dispositions of the air are shown by the new moon, though still more on the fourth rising, as if her newness were then confirmed. But the full moon itself is a better prognostic than any of the days which succeed it.
17. From long observation, sailors suspect storms on the fifth day of the moon.
18. If the new moon is not visible before the fourth day, the air will be unsettled for the whole month.
19. If at her birth, or within the first few days, the lower horn of the moon appear obscure, dark, or any way discoloured, there will be foul and stormy weather before the full. If she be discoloured in the middle, it will be stormy about the full; but if the upper horn is thus affected, about the wane.
20. If, on her fourth day, the moon is clear, with her horns sharp, not lying entirely flat, nor standing quite upright, but something between the two, there is a promise mostly of fair weather till the neat new moon.
21. If on that day she rises red, it portends wind; if reddish or dark coloured, rain; but neither of these portend anything beyond the full.
22. An erect moon is almost always threatening and un-favourable, but principally denotes wind. If however she ap-pear with blunt and shortened horns, it is rather a sign of rain.
23. If one horn of the moon is sharp and pointed, the other being more blunt, it rather indicates wind; but if both are so, it denotes rain.
24. A circle or halo round the moon signifies rain rather than wind; unless the moon stands erect within the ring, when both are portended.
25. Circles round the moon always foretel wind from the side where they break; and a remarkable brilliancy in any part of the circle deuotes wind from that quarter.
26. Double or treble circles round the moon foreshadow rough and severe storms; and much more so, if these circles are not pure and entire, but spotted and broken.
27. Full moons, with regard to colours and halos, have per-haps the same prognostics as the fourth risings; but the fulfil-ment is more immediate and not so long deferred.
28. The weather is generally clearer at the full than at the other ages of the moon; but in winter the frost then is some-times more intense.
29. The moon appearing larger at sunset, and not dim but luminous, portends fair weather for several days.
30. Eclipses of the moon are generally attended by wind; eclipses of the sun by fair weather; but neither of them are often accompanied by rain.
31. Wind must be expected both before and after the conjunctions of all the other planets with one another, except the sun; but fair weather from their conjunctions with the sun.
32. Rains and showers follow upon the rising of the Pleiades and Hyades, but without wind; storms upon the rising of Orion and Arcturus.
33. Shooting stars, as they are termed, foretel immediate winds from the quarter whence they shot. But if they shoot from different or contrary quarters, there will be great storms both of wind and rain.
34. When small stars, like those called Aselli, are not visible in any part of the sky, there will be great storms and rains within a few days; but if these stars are only obscured in places, and are bright elsewhere, they denote winds only; but sooner.
35. A uniform brightness in the sky at the new moon or the fourth rising presages fair weather for many days. If the sky is uniformly overcast, it denotes rain; if irregularly overcast, wind from the quarter where it is overcast. But if it suddenly becomes overcast without cloud or fog, so as to dull the brightness of the stars, rough and serious storms are imminent.
36. An entire circle round any planet or larger star forebodes rain; if the circle be broken, there will be wind from the quarter where it breaks.
37. When the thunder is more continuous than the lightning, there will be great winds; but if it lightens frequently between the thunder-claps, there will be heavy showers with large drops.
38. Thunder in the morning denotes winds; at noon, showers.
39. Rolling thunder, which seems to be passing on, foretels wind; but sharp and interrupted cracks denote storms both of wind and rain.
40. Lightning in a clear sky signifies the approach of wind and rain from the quarter where it lightens; but if it lightens in different parts of the sky, there will be severe and dreadful storms.
41. If the lightning is in the colder quarters of the hea-ven, as the north and north-east, hailstorms will follow; but if in the warmer, as the south and west, there will be showers, with a sultry temperature.
42. Great heats after the summer solstice generally end in thunderstorms; but if these do not come, in wind and rain, which last for many days.
43. The ball of fire, called Castor by the ancients, that ap-pears at sea, if it be single, prognosticates a severe storm (seeing it is Castor the dead brother), which will be much more severe if the ball does not adhere to the mast, but rolls or dances about. But if there are two of them (that is, if Pollux the living brother be present), and that too when the storm has increased, it is reckoned a good sign. But if there are three of them (that is, if Helen, the general scourge, arrive), the storm will become more fearful. The fact seems to be, that one by itself seems to indicate that the tempestuous matter is crude; two, that it is prepared and ripened ; three or more, that so great a quantity is collected as can hardly be dis-persed.'
44. If the clouds appear to drive fast when there is no wind, expect wind from that quarter from which they are driven. But if they gather and collect together, on the sun's approach to that part, they will begin to disperse; and then if they disperse towards the north it prognosticates wind, if towards the south, rain.
45. Black or dark clouds arising at sunset prognosticate rain; on the same night, if they rise in the east opposite the sun; if close to the sun in the west, the next day, accom-panied with wind.
46. If the sky clears and the clouds commence to break in the quarter opposite the wind, it will be fine; but if it clear up to windward, it indicates nothing, and leaves the weather uncertain.
47. Sometimes the clouds appear to be piled in several tiers or stories, one above the other (Gilbert declares a that he has sometimes seen and observed five -together), whereof the lowest are always the blackest; though it sometimes appears otherwise, as the whiter most attract the sight. Two stories, if thick, portend instant rain (especially if the lower one appear overcharged); many tiers denote a three days' rain.
' (Pliny, ii. 37. 2 Gilbert, Phys. iv. I)
48. Fleecy clouds, scattered over the sky, denote storms; but clouds which rest upon one another like scales or tiles portend dry and fine weather.
49. Feathery clouds, like palm branches or the fleur-de-lis, denote immediate or coming showers.
50. When mountains and hills appear capped by clouds that hang about and embrace them, storms are imminent.
51. Clouds before sunset of an amber or gold colour, and with gilt fringes after the sun has sunk lower, foretel fine weather.
52. Clay-obloured and muddy clouds portend rain and wind.
53. If a little cloud suddenly appear in a clear sky, especially if it come from the west, or somewhere in the south, there is a storm brewing.
54. If mists and fogs ascend and return upwards, they denote rain; and if this take place suddenly, so that they appear to be sucked up, they foretel winds; but if they fall and rest in the values, it will be fine weather.
55. A white loaded cloud, called by the ancients d white tempest, is followed in summer by showers of very small hail; in winter, by snow.
56. A calm autumn portends a windy winter; a windy winter a wet spring; a wet spring a serene summer; a serene summer a windy autumn; so that the year, according to the proverb, is seldom its own debtor, and the seasons are never the same two years together.
57. Fires burning paler than usual, and murmuring within, are significant of storms. If the flame shoot in a twisting and curling form, it principally denotes wind; but fungous growths or excrescences on the wicks of lamps rather foreshadow rain.
58. Coals, when they burn very bright, foretel wind; and likewise when they quickly cast off and deposit their ashes.
59. When the-surface of the sea in harbour appears calm, and yet there is a murmuring noise within it, although there is no swell, a wind is coming.
60. The shores sounding in a calm, and the sea itself beating with a moaning or echo louder and clearer than usual, are signs of wind
61. If foam, white circles of froth, or bubbles of water, appear here and there on a calm and smooth sea, they prognosticate wind. If these signs be more striking, they denote severe storms.
62. Glittering foam (called sea-lungs) in a heavy sea foretels that the storm will last for many days.
63. The sea swelling silently and rising higher than usual in the harbour, or the tide coming in quicker than ordinary, prognosticates wind.
64. A sound from the mountains, an increasing murmur in the woods, and likewise a kind of crashing noise in the plains, portend winds. An extraordinary noise in the sky, when there is no thunder, is principally due to winds.
65. Leaves and straws playing in the air when no breeze is felt, the down of plants flying about, and feathers floating and playing on the water, show that winds are at hand.
66. Water-fowl meeting and flocking together, but especially sea-gulls and coots flying rapidly to shore from the sea or lakes, particularly if they scream, and playing on the dry land, foreshow wind; and this is more certain if they do it in the morning.
67. On the other hand, land birds, especially crows, when they go to the water, beat it with their wings, throw it over them and scream, foreshow storms.
68. Divers and ducks prune their feathers before a wind; but geese seem to call down the rain with their importunate cackling.
69. A heron, when it soars high so as sometimes to fly above a low cloud, shows wind; but kites flying high show fair weather.
70. Ravens, when they croak continuously, denote wind; but if the croaking is interrupted or stifled, or at longer intervals, they show rain.
71. The whooping of an owl was thought by the ancients to betoken a change of weather, from fair to wet, or from wet to fair. But with us an owl, when it whoops clearly and freely, generally shows fair weather, especially in winter.
72. If birds that dwell in trees return eagerly to their nests, and leave their feeding ground early, it is a sign of storms; but when a heron stands melancholy on the sand, or a raven stalks about, it only denotes rain.
73. Dolphins sporting in a calm sea are thought to prognosticate wind from that quarter whence they come; but if they play in a rough sea, and throw the water about, it will be fine. Most other kinds of fish, when they swim at the top of the water, or sometimes leap out of it, foretel rain.
74. Swine are so terrified and disturbed and discomposed when the wind is getting up, that countrymen say, that this animal alone sees the wind, and that it must be frightful to look at.
75. Spiders work hard and spin their webs a little before wind, as if desiring to anticipate it; for they cannot spin when the wind begins to blow.
76. The ringing of bells is heard at a greater distance before rain; but before wind it is heard more unequally, the sound coming and going, as we hear it when the wind is blowing perceptibly.
77. Pliny mentions it as a fact, that trefoil bristles and erects its leaves against a storm.'
78. He likewise asserts, that vessels containing eatables sometimes leave a sweat behind them in the storerooms; and that this is a sign of fearful storms.
Admonition. Since rain and winds are made of nearly the same matter, and since, by reason of the reception of the newmade air into the old, some condensation of the air always takes place before wind, as is shown by the moaning of the shores, the high flight of the heron, and other things; and since the air is in like manner condensed before rain (though when the rain falls it is afterwards more contracted, when the wind rises on the contrary it is more expanded), it must needs be that rains and winds have many common prognostics. With reference to these consult the Prognostics of Rains under their own title.
Imitations of Winds.
with referenceto the 83rd
If men could only bring themselves not to fix their inquiry. a of In-thoughts too intently on the consideration of the subject before them, rejecting everything else as irrelevant, and not to refine with endless and mostly unprofitable speculations thereon, they would never be so dull as they are wont to be, but by a free passage and transference of their thoughts they would find many, things at a distance which near at hand are concealed. And therefore, in the law of nature, as well as in the civil law, we must proceed with sagacity, of mind to look for like and analogous cases.
t Pliny, xi.
1. Bellows are with men as the bags of AEolus, whence a man may draw wind, according to the proportion of man. The passes and insterstices of mountains, and the winding passages of buildings, are likewise nothing else than large bellows. Bellows are principally used for rousing a flame, or blowing the organ. The principle is, that they suck in the air to prevent a vacuum (as the saying is), and drive it out by compression.
2. Hand-fans are likewise used to make a wind and to produce coolness by gently impelling the air.
3. I have already, made some observations on cooling rooms in summer, in my reply to the 9th article of inquiry. But other and more perfect methods may be devised, especially by drawing the air in at one part, and discharging it at another, after the manner of bellows. The present methods only relate to simple compression.
4. Winds in the bodies of men and animals excellently correspond to the winds of the greater world. For they are both generated from moisture and alternate with it, as winds and rains do; they are likewise dissipated and made to perspire by a strong heat. And hence we may transfer this observation to the winds; namely, that they are produced from a matter which yields a tenacious vapour, that is not easily resolved; as beans, pulse, and fruit. And this holds good also in the greater winds.
5. In distilling vitriol and other fossils of a flatulent nature, very large and capacious receivers are required; as otherwise they would be broken.
6. The wind made by the nitre mixed in gunpowder, that explodes and inflates the flame, not only imitates but exceeds all other winds, except those in thunderstorms.
7. The force of this wind is compressed in machines made by man, as guns, mines, and powder magazines when they blow' up. But whether a great quantity of gunpowder fired in the open air would likewise by the commotion of the air raise a wind that would last for many hours, has not yet been tried.
8. Quicksilver contains a flatulent .and expansive spirit, so that (as some maintain) it resembles gunpowder, and a little of it mixed with gunpowder makes the powder stronger. Chemists also say that gold, in certain preparations of it, makes dangerous explosions, almost like thunder. But of these things I have no experience.
The motion of winds is in most respects seen in the motions of water, as in a .mirror.'
Great winds are inundations of the air, the resemblance of which we see in inundations of the waters; both arising from an increase of quantity..
Waters either descend from above or. spring from the earth; and so some winds are driven from above, some rise from below.
Sometimes there are contrary motions in rivers, the tide flowing one way,, the stream of the river the other; and yet there is only one motion, because the course of the tide prevails. And so, when contrary winds blow, the greater subdues the less.
In currents of the sea and of some rivers, it sometimes happens that the stream at the top of the water moves in a contrary direction to that below. And so in the air, when contrary winds blow together, one flies above the other.
There are cataracts of rain confined in a narrow space; so are there whirlwinds.
Waters, if disturbed, have an undulating besides a progressive motion; at one time rising into ridges, at another descending into furrows. And this likewise happens to the winds, except that they have not the motion of gravity.
There are also other- resemblances, which may be observed from the things already inquired.
Provisional Rules respecting the Winds.
Transition. Rules are either particular or general; but here both kinds are provisional. For as yet I do not pronounce certainly upon anything. Particular rules may be drawn or expressed from almost every article; certain general ones; but only a few, I shall myself select, and subjoin.
' (Cf. Aristot. Problems, xxvi. 38., and Meteorol. i. 13.).
1. Wind is merely air in motion: nothing besides: au put in motion either by simple impulsion, or by the mixture of vapours.
2. Winds arising from the simple impulsion of the air are produced in four ways; namely, by the natural motion of the air, by the expansion of the air in the path of the sun, by the contraction of the air from sudden cold, or by the compression of the sir from external bodies.
There may also be a fifth way; namely, by the agitation and concussion of the air from the stars; but let matters of this kind be passed in silence for the present, or only listened to with suspicion.
3. The principal cause of winds produced by the mixture of vapours is the overcharging of the air by the air newly created from vapours; for thereby the bulk of the air is increased and requires more room.
4. A small increase in the quantity of air causes a great swell in every part of the atmosphere; so that this new sir from the resolution of vapours contributes more to the motion than to the matter; but the great body of wind is composed of the former air. Nor does the new air drive the old air before it, as if they were separate bodies; but both being mixed together require greater room.
5. Any other concurrent principle of motion, besides the surcharge of the air, acts as an accessory to strengthen and increase the chief one. And this is the reason why high stormy winds seldom rise from the simple surcharge of the air.
6. There are four accessories to the surcharge of the air; namely, exhalation from below, precipitation from what is called the middle region of the air, dispersion from the formation of a cloud, and mobility and acrimony of the exhalation itself.
7. The motion of the wind is almost always lateral. That created by the simple surcharge of the air is so from the very first; that caused by exhalations from the earth or repercussion from above becomes so soon after; unless the eruption, precipitation, or recoil, are extremely violent.
8. The air will submit to some compression before it is conscious of being overcharged, and before it impels the air contiguous to it. This will account for all winds being somewhat more condensed than air at rest.
9. Winds are allayed in five ways; namely, by the meeting, incorporation, elevation, transportation, or deficiency of vapours.
10. The gathering of vapours, and in fact of the air itself into rain, is caused in four ways; namely, by the excess of quantity, or the condensation by cold, or the compulsion of contrary winds, or the repercussion from obstacles.
11. Both vapours and exhalations are the matter of winds. Rain is never generated from exhalations, but winds most frequently proceed from vapours. There is however this difference; that winds generated from vapours more easily incorporate themselves with the pure air, are sooner calmed, and are not so stubborn as those arising from exhalations.
12. The modification and different conditions of heat have as much to do with the generation of winds, as have the quantity or conditions of matter.
13. The sun's heat, in the generation of winds, should have just power enough to raise them; neither so abundant as to collect them into rain, nor so scanty as entirely to scatter and disperse them.
14. Winds blow from the direction of their nurseries. When however these nurseries are situated in different quarters, different winds generally blow together, till the stronger either overpowers the weaker, or turns it into its own current.
15. Winds are generated everywhere, from the surface of the earth to the cold region of the sir; but the common winds are generated close at hand, the stronger winds above.
16. Countries where the attendant winds are warm are hotter, and countries where these winds are cool are colder, than in proportion to their climate.
Desideratum. 1. A better method of ordering and disposing the sails of ships, so as to make more way with less wind; a thing very useful in shortening sea voyages, and saving expense.
Approximation. No approximation has been hitherto invented which in practice should exactly correspond to this requirement. But for this consult the major observations on the 26th article.
Desideratum. 2. A method of constructing windmills with sails, so as to grind more with less wind; a thing likewise useful and lucrative.
Approximation. Consult on this point our experiments in reply to the 27th article, where the thing appears to be almost done.
Desideratum. 3. A method of foreknowing the risings, fallings, and times of winds; a thing useful in navigation and agriculture, but especially so in selecting the times for naval engagements.
Approximation. Many things have been remarked in the inquiry which bear upon this subject, but especially the reply to the 32nd article. Now however that the cause of the winds is explained, the more diligent observations of posterity (if it shall care at all about these things) will discover more certain prognostics.
Desideratum. 4. A method of prognosticating and forming an opinion upon other things by means of the winds; for instance, whether in any part of the sea there are continents or islands, or whether the sea is open; a thing of use in new and unknown navigations.
Approximation. The observation about the periodical winds, which Columbus appears to have used, is an approximation to this.
Desideratum. 5. A method likewise of foretelling, every year, whether corn and fruit will be abundant or scarce; a thing useful and lucrative in speculative sales and purchases; of which an instance is related in the case of Thales when he bought up the olives.'
Approximation. Some observations under the 29th article of inquiry, on malignant or tearing winds, and the times when they are prejudicial, bear upon this point.
Desideratum. 6. A method likewise of foretelling the diseases and epidemics for every year; a thing useful to the reputation of physicians, if such things could be predicted; as also for the causes and cures of diseases, with some other matters of business.
Approximation. Some observations on the 30th article of inquiry have likewise reference to this question.
Admonition. For predictions from the winds concerning crops, fruits, and diseases, consult the Histories of Agriculture and Medicines.
Desideratum. 7. A method of raising and allaying winds.
(1 Ding. Laert. i. 26.)
Approximation. There are some superstitious and magical ceremonies connected with this subject, which do not appear worthy to be received into a serious and exact natural history. Nor does any approximation at present occur to me. It will however be of service thereto, to inspect and inquire thoroughly into the nature of the air,; to see if there be anything which, on being communicated in a small quantity to the sir, can excite and multiply the motion of dilatation or contraction in the body of the air. For if this could be done, the raising and calming of the winds would naturally follow; like Pliny's experiment, if it be true, of throwing vinegar against the whirlwind.' Another method might be, by letting out subterranean winds wherever a great quantity was collected, as is told of the well in Dalmatia. But it is difficult to discover these places of confinement.
Desideratum. 8. Methods of performing many amusing- and wonderful experiments by the motion of the winds.
Approximation. Such questions I have no time to consider. The approximation is the common games which depend on the wind; and, no question, many pleasant things of this kind, both with regard to sound and motion, may be invented.