CHAPTER IV.

Between the parallels of 35 deg. north latitude, and 35 deg. south latitude--changing its location within this limit at different seasons of the year--encircling the earth, and covering about one-half of its area--we find the trade-wind region. In this region are the simple and uniform arrangements, which extend every where, and produce all the atmospheric phenomena. In the center of it we find that movable belt of continual or daily rains, and comparative calms, particularly near its center, about four hundred and fifty miles in width upon the Atlantic, and over Africa, and the eastern portions of the Pacific, and something more over South America and the West Indies, the western portion of the Pacific and the Indian Ocean, to which we have already alluded. This belt of rains and calms follows the trades and sun, in their transit north and south, from one tropic to the other--its width and extension depending upon the volume of trade-winds existing on the sides of it. Its southern edge, when the sun is at the southern solstice, extends to 7 deg. south in the Atlantic, to 10 deg. south in the Indian Ocean, and still further, probably, over South America: on this point I do not pretend to be accurate, for accuracy is not essential. When the sun is at the northern solstice the southern edge is carried up as far as 12 deg. north, over the Atlantic, and still further over the northern portions of South America, the West Indies, and Mexico. It travels, therefore, from south to north, over from twenty to forty degrees of latitude. The presence of this belt of rains over any given portion of the inter-tropics, gives that portion its rainy season, and its absence, as it moves to the north, or the south, gives the portion from which it has moved, its dry season. It passes in its transit twice each year over some portions of the country, Bogota, for instance, and two corresponding rainy and dry seasons result. Its presence, and character, and movements, are as fixed and regular, over from twenty-five to forty degrees of the earth's surface, and all around it, as the presence and movements of the sun over the same area.

At the northern edge of this movable belt of rain, and extending in some places, particularly in the Pacific Ocean, north about 20 deg., or about one thousand four hundred miles, and in other places a less distance, the N. E. trade winds prevail, blowing toward and into it from N. N. E., N. E., and E. N. E., averaging about N. E. At the south line of this belt of rains, extending south from twenty-five to thirty degrees, or from sixteen hundred to two thousand miles, the S. E. trades blow toward and into it, from the S. E., S. S. E., or E. S. E., averaging about S. E. Of course the northern limit of the N. E. trades travels north and south with the belt of rain, toward which it blows; and so the southern limit of the S. E. trades travel in like manner with the rainy belt, or rather, to speak with entire accuracy, the belt of rain moves with the trades, and the trades follow the verticality of the sun. The following diagrams exhibit approximately, and with sufficient accuracy for illustration, the situations of the rainy belt and the trades, when at their northern and southern limit, as well as the manner in which it must give certain localities two rainy seasons each year, in its transit north and south.

At the northern and southern limits of the trade-winds, and extending from them to the poles, are found the variable winds and irregular extra-tropical rains, all over the earth, which are shown by the shading on the maps. This line of extra-tropical rains descends to the south, following the retreating trades as they descend in our winter, and recedes north before the trades when they return in spring and summer, so that at the outer limit of the trades respectively, toward the poles, the line of extra-tropical rains will be found, receding or following that limit, as the trades pass up and down with the sun. From the north pole to the northern limit of the N. E. trade-winds, wherever found, whether at 38 deg. north latitude, as in some places in summer when the sun is at the tropic of Cancer; or whether at 20 deg. to 30 deg. north latitude, as in our winter, when the sun is at the tropic of Capricorn; the extra-tropical rains prevail. A state of things precisely similar exists between the south pole and the southern limit of the S. E. trades. Between this northern limit of the N. E. trades and the northern line of the inter-tropical belt of rains, wherever situated (with two exceptions, to which we have alluded and shall allude again), there is, for the time being, a dry season; and a like dry season between the southern line of the belt of rains and the southern limit of the S. E. trades. We have, therefore, extending around the earth, a belt of daily tropical rains, near the center,--two belts of drought which are mainly trade-wind surfaces, one on each side of the central rainy belt,--extending to the outward limits of the trades and the line of extra-tropical rains; and these rainy and dry belts, moving up and down after the sun, a distance of from twenty to forty degrees of latitude, each year.

Such are the main phenomena, at the surface, in the trade-wind region. Ascending a step higher in the atmosphere, we find, above the surface-trades, a counter-trade, running, not in the opposite direction, but at right angles, or nearly so. The counter-trade which issues from the northern side of the rainy belt, running to the N. W. or W. N. W., and the counter trade which issues from the southern side, running to the S. W. or W. S. W., varying, as the trades do in direction in different localities. These counter-trades are continuations of the surface trades, which, ascending in their course, have threaded their way through the opposite trade in the rainy belt, and are continuing on at the same angle, and in the same direction at which they blew upon the surface, and in obedience to the same law. This is apparent from several considerations.

1st. They issue at the same angle, and over the top of the surface trades. In the West Indies and elsewhere, this has been ascertained and proved by the course of the storms, and the rotation of their surface winds, and observation.

2d. We can not suppose the N. E. trade to be reflected, and turn back over itself at a right angle. That would be impossible, even if there were a wall of solid material there for it to blow against. Air is a peculiar fluid, and it stratifies with astonishing ease. He who supposes that a current of air put in motion can be turned aside by another current, or by the atmosphere at rest, or can be made to mingle, is mistaken. It will stratify, and force itself onward through the adjacent and opposing atmosphere, and in a right line. I have observed some remarkable instances of this character.

3d. The cause which operates to produce the surface trades, still operates upon the current to carry it over into the other hemisphere; a counter-trade, as we shall see. It is impossible, therefore, to believe that the surface-trades as they arrive at the belt of rains and calms, turn at a right angle, or at any angle, and return: and impossible to doubt that they pass through each other in this belt, and out at the opposite side, as upper currents, at the same angle at which they entered. Of course the N. E. trade of the Atlantic becomes the N. E. counter-trade of South America, carrying their storms in a S. W. direction, and the S. E. trade of the Atlantic the S. E. counter-trade of the West Indies, carrying all their storms in a N. W. direction; and what is true of them is true of the trade winds every where, all over the globe, over the land and over the sea.

Doubtless here some one will say, our upper current is a S. W. current. True, the S. E. trade which enters the belt of rains, and issues out on the north, a S. E. upper current or counter-trade, keeps that course until it arrives at the northern limit of the surface trade, when, in obedience to another law, which we shall notice, it gradually decends near the surface, curves to the eastward, and becomes the S. W. current which passes over us. And so we have the S. E. trade-wind of the South Atlantic, with its moisture, warmth, electricity, and polarity, over, and perhaps sometimes around us, dropping the electric rain which makes glad our fields; giving us, when not prevented by other conditions, the balmy air of spring, the Indian summer of autumn, and the mild mitigating changes of winter; and thus, our rivers, which run into the sea, return to us again.

But let us go back to the trade-wind region--the region of regularity and uniformity--and examine somewhat more attentively its features, that we may more fully understand the character of this counter-trade.

Here are 60 deg. at least of the 180 deg. of the earth's surface, and at its largest diameter, covered in the course of the year, and of their travels, by the trade-winds at the surface, the counter-trades above, and the belt of rains and comparative calms, formed by the action of the opposite trades, as they thread their way through each other, to assume the relation of counter-trades. Truly the magnitude, simplicity, and regularity of this machinery are most wonderful.

There are, however, some apparent anomalies which deserve attention. Here are most distinctly marked the rainy and dry seasons, existing side by side. Here are the rainless portions of the earth, already but briefly alluded to; here the monsoons, and another peculiarity, viz.: the gathering of the counter-trades upon the western sides of the two great oceans, into two aerial currents of greater volume, analogous somewhat to the two gulf streams of those oceans. Let us examine these anomalies.

The rainy and dry seasons depend, as we have seen, upon the transit north and south of the rainy belt, or belt of comparative calms. Wherever this belt may happen on any given day to be situated, each side of it the trades prevail, it is dry, the earth is parched, and vegetation withers. These changes are graphically described by Humboldt in his "Views of Nature," as they occur on the northern portions of South America, as follows: "When, beneath the vertical rays of the bright and cloudless sun of the tropics, the parched sward crumbles into dust, then the indurated soil cracks and bursts, as if rent asunder by some mighty earthquake. The hot and dusty earth forms a cloudy vail, which shrouds the heavens from view, and increases the stifling oppression of the atmosphere; while the east wind (i. e. trade-wind), when it blows over the long heated soil, instead of cooling, adds to the burning glow.

"Gradually, too, the pools of water, which had been protected from evaporation by the now seared foliage of the fan-palm, disappear. As in the icy north animals become torpid from cold, so here the crocodile and the boa-constrictor lie wrapped in unbroken sleep, deeply buried in the dried soil. Every where the drought announces death, yet every where the thirsty wanderer is deluded by the phantom of a moving, undulating, watery surface, created by the deceptive play of the reflected rays of light (the mirage). A narrow stratum separates the ground from the distant palm-trees, which seem to hover aloft, owing to the contact of currents of air having different degrees of heat, and therefore of density. Shrouded in dark clouds of dust, and tortured by hunger and burning thirst, oxen and horses scour the plain, the one belowing dismally, the other with outstretched necks snuffing the wind, in the endeavor to detect, by the moisture in the air, the vicinity of some pool of water not yet wholly evaporated.

"Even if the burning heat of day be succeeded by the cool freshness of the night, here always of equal length, the wearied ox and horse enjoy no repose. Huge bats now attack the animals during sleep, and vampyre-like suck their blood; or, fastening on their backs, raise festering wounds, in which mosquitos, hippobosces, and a host of other stinging insects, burrow and nestle. Such is the miserable existence of these poor animals, when the heat of the sun has absorbed the waters from the surface of the earth.

"When, after a long drought, the genial season of rain arrives, the scene suddenly changes. The deep azure of the hitherto cloudless sky assumes a lighter hue. Scarcely can the dark space in the constellation of the Southern Cross be distinguished at night. The mild phosphorescence of the Magellanic clouds fades away. Even the vertical stars of the constellations Aquila and Ophiuchus, shine with a flickering and less planetary light. Like some distant mountain, a single cloud is seen rising perpendicularly on the southern horizon. Misty vapors collect and gradually overspread the heavens, while distant thunder proclaims the approach of the vivifying rain. Scarcely is the surface of the earth moistened, before the teeming steppe becomes covered with Killingiae, with the many-panicled Paspalum, and a variety of grasses. Excited by the power of light, the herbaceous Mimosa unfolds its dormant, drooping leaves, hailing, as it were, the rising sun in chorus with the matin song of the birds, and the opening flowers of aquatics. Horses and oxen, buoyant with life and enjoyment, roam over and crop the plains. The luxuriant grass hides the beautiful and spotted jaguar, who, lurking in safe concealment, and carefully measuring the extent of the leap, darts, like the Asiatic tiger, with a cat-like bound on his passing prey."

Such is Humboldt's description of the dry season on the Orinoco, and the return of the belt of rains from the south.

Again, within this trade-wind region are the rainless countries. These are portions of the earth which the equatorial rainy belt does not ascend far enough north in summer to cover, nor does the southern edge of the extra-tropical regular rains descend, in winter, far enough south to cover them, and where, of course, rain seldom, if ever, falls. Such are the central parts of the Desert of Sahara, Egypt, Arabia, portions of Affghanistan, Beloochistan, and the western parts of Hindoostan, to the north of the inter-tropical belt, and a similar state of things exists south of the equator in parts of South America, Africa, and New Holland, although upon a comparatively small surface.

Again, another anomaly is the gathering of the trade winds into greater volumes, on the westerly side of the great oceans, and the consequent carrying of the equatorial rainy belt up to the region of extra-tropical rains, on the eastern side of the great continents of Asia and North America, and the peculiar liability of these aerial gulfs to hurricanes and typhoons. Such an aerial gulf gathers over the Caribbean Sea, and the West Indies. Passing across the Gulf of Mexico, it enters over Texas, and Louisiana, and the other southern states; its western edge passing north in autumn and winter, on the eastern side of the highlands of Western Texas, New Mexico, and the Great Desert; curving, as all counter-trades do, to the eastward as soon as it passes the limit of the N. E. trades, and spreading out over our favored country, leaving the evidence of its pathway in the greater quantities of rain, which fall annually upon its surface. This gathering deprives a portion of the Atlantic, north of the tropics, of its share of the counter trade, and there, as every where, where the volume of counter-trade is small, storms and gales are infrequent, and of less force, and comparative calms prevail. That portion of the Atlantic has long been known as "the horse latitudes," a name given to it by our Yankee sailors, because, there, in former times, the old-fashioned, low-decked, flat-bottomed, horse-carrying craft of New England, bound for the West Indies, often floundered about in the calms and baffling winds, until their animals perished for want of water, and were thrown overboard. Lieutenant Maury, in his most praiseworthy and exceedingly useful investigation of "The Winds and Currents of the Ocean," has defined the situation of these calms and baffling winds at different seasons--for they move up and down, of course, with the motion of the whole machinery--and enabled navigators to avoid them, by running east before they attempt to make southing; and very materially shortened the voyages to the equator.

A like gathering, in volume, of the S. E. trade, on the western side of the Pacific, enters over Asia, and covers China and Malaysia, extending, in its western course, nearly as far as the western edge of Hindoostan. In this concentrated volume of counter-trade, and owing to its concentrated action, form and float the typhoons of the China Sea, and of the Bay of Bengal; and to this anomalous aerial gulf stream, the S. E. portions of Asia, from the western desert of Hindoostan, to the eastern portion of China, north of the rainy belt, owe their great supply of moisture and fertility, and their peculiar climate. The western line of this volume of counter-trade is marked by the eastern portion of the rainless region of Beloochistan, and the north-western deserts of India, as the western edge of our concentrated volume of counter-trade, is marked by the arid plains of northern Mexico, western Texas, and New Mexico. On the south of the equatorial rainy belt, there is no corresponding aerial gulf of equal volume, as there is no corresponding gulf stream of equal magnitude. On the western side of the Indian Ocean we find a gathering of the N. E. trades from the Bay of Bengal and the Indian Ocean, in which form and travel the hurricanes which prevail--traveling to the southward and westward--about the Isle of France or Mauritius; and the lagullus oceanic current, which runs down to the S. W. toward the Cape of Good Hope. But the extension of South America to the eastward, under, or just south of the N. E. trades, does not permit the formation of such a concentrated volume on the western side of the Atlantic, nor is the strength or regularity of the N. E. trades, on that ocean, equal to those of the S. E.

Nor is the magnetic intensity on the eastern and middle portions of the Pacific, sufficient to produce such a concentration, in large volume, there. The trades over that ocean, therefore, curve without concentration, except a partial one, over the western groups of Polynesia, which the Asiatic line of magnetic intensity approaches and where hurricanes are sometimes found, until we arrive near the eastern line of magnetic intensity, on the eastern side of Asia. We shall, hereafter, have occasion to follow the anomalous concentrated volumes of the S. E. counter-trade, of the northern tropic, on the western side of the great oceans, in explanation of some of the phenomena which we find north of the trade-wind region. Suffice it here to add, that if it were not for the concentration of these counter-trades, on the western side of the great oceans, the rainless region between the parallels of 20 deg. and 30 deg. would encircle the earth; and China and the Eastern United States would have a distinctly marked rainy and dry season, as have California, the Barbary States, Syria, Persia, and other countries which lie north of the rainless region, within the summer range of the N. E. trades, but also within the winter descending range of the belt of extra-tropical rains.

Another anomaly which we find in the trade-wind region, is the monsoon. There are several of them, but they are found, in the greatest strength and regularity, in the Indian Ocean. Another, defined by the investigations of Maury, is found on the west coast of Africa, extending out over the Atlantic. Another prevails on the western coast of South and Central America. The etesian winds of the Mediterranean are but the N. E. trades, whose northern limit is carried up in summer, by the transit of the connected machinery, to the north, over that sea. The N. E. and S. E. monsoons, so called, of the Indian Ocean, are but the regular trades, blowing when the belt of rains is absent, as they do all over the globe. The N. W. monsoon, south of the equator, in the vicinity of New Holland; the S. W. monsoon which blows from the Arabian Sea, in upon Hindoostan; the S. W. monsoon of the Atlantic, south of the Cape De Verde Islands; and the variable west monsoon winds of the west coast of Southern and Central America, and Southern Mexico (known under several different names, but chiefly by that of Tapayaguas), are all that deserve attention as such.

At first sight they appear to be anomalies, but the facts declare their character with perfect certainty. First, they are not continuous, like the trades, but prevailing winds, and are storm winds; they always blow toward a region, or portion of the ocean, covered at the time by clouds and falling weather.

Second, they do not blow upon, or toward, heated surfaces of land or water--i. e., toward the dry and parched surfaces, where the dry season prevails, or from adjoining cold waters on to warm surfaces, but toward the land or water situated under the rainy belt. They are therefore incident storm winds, (as our easterly winds are incident storm winds) of the rain clouds of the tropics. They blow in upon the land, under the belt of rains, while that belt with its daily cloud, and inducing electric action, is over it, and follow that belt in its transit north and south. They blow from the warm south polar current of the Atlantic, which flows N. W. from the coast of Africa, toward the inshore north polar current, which is there flowing south, but under the belt of rains. In the Indian Ocean they blow from the center of that ocean, and the Arabian Sea, toward the belt which hangs over Hindoostan, from the S. W.; and when the rainy belt travels south they still blow toward, and under it, from the Indian Ocean, but of course from the N. W. The heated character of the waters of the Indian Ocean and Arabian Sea, which receive no polar currents, but heated waters from the Persian Gulf, and from rivers which flow into the Bay of Bengal over the heated plains of a tropical country, explain this. So, too, the monsoon of the Atlantic Ocean, does not blow north of the Cape De Verde Islands,--where the heated surface of Sahara, burning with the rays of a vertical sun, has a temperature sometimes ranging from one hundred and forty to one hundred and sixty degrees--but remains under the rainy belt, drawn from the heated waters which flow up from the South Atlantic, and travels north as the rainy belt travels north in summer, and south to the Gulf of Guinea, as that travels south in winter. The same is true of the Pacific monsoon, the Tapayaguas, the least marked of all, which blows in during the rainy season upon the west coast of Southern Mexico, and of Southern and Central America. They are all incident rain or storm winds, blowing in upon the land, or on to a colder surface of different polarity, during the rainy season; and if it were possible to catch one of our north-easters, in its passage over our country to the eastward, and anchor it to the Alleghanies, "paying out" so to have it reach in part over the Atlantic, and keep it there in operation six months, we should have a continual easterly wind under it; a monsoon more strongly marked than the monsoons of the Indian, or Atlantic Oceans. The received theory in relation to them is a fallacy.

Recapitulating, then, all the phenomena, we have,--Surface-trades, blowing toward the center, passing through each other, and continuing on as upper or counter-trades; a belt of rains, with calms near the center, formed by the trades where they meet and pass through each other, which travels with them north and south following the sun; two belts of drought, following the belt of rains and the trades, and followed by the extra-tropical line of rains, as it travels with the trades and the rainy belt, leaving a part of the earth which the equatorial rainy belt does not travel far enough north, nor the extra-tropical line of rains far enough south to cover, and which is consequently a rainless region; the monsoons, which are but incidents of the rainy belt, and the gathered volumes of counter-trade, on the west of the two great oceans, which usurp the place of the N. E. trades, carrying the rainy belt up to the region of extra-tropical rain, and preventing the rainless region from encircling the earth.

Upon what cause do these great central phenomena, so vast, so regular, so wonderful, depend? What is the motive power of this connected atmospheric machinery, whose action and influence extend over the entire globe?

"Heat, heat," say the text books, the Professors, the votaries of meteorology. "All these phenomena are owing to the heat of the sun. It heats the ocean and the earth--the air is thereby heated and rises, the cold air rushes in from below, then the ascended current rolls off each way at the top toward the pole, acquiring a westerly motion from the rotation of the earth, slipping away from under it, and a different, viz.: an easterly motion, after reaching the latitude of 30 deg., from the same rotation; and all the winds and disturbances of the atmosphere are produced in the same way. They are produced by the action of heated surfaces upon the adjacent atmosphere."

This is the great theory of meteorologists, by which they attempt to account for the various atmospherical disturbances, of both tropical and extra-tropical regions.

The whole theory is a fallacy--it will not stand the test of a careful examination. The bases of the theory, which are assumed to be facts, are not so. The agent has not the power claimed for it. A heated surface, alone, never caused any considerable ascending current, or if it did, never produced a mile of wind. I repeat it, the theory and all incidental ones--the thousand explanatory and modifying theories, and hypotheses--the whole system--is without foundation in fact, and will not bear a critical examination.

Let us see if this language is stronger than the facts will warrant.

The theory assumes that both the land and water, under this central belt, where the air is supposed to be rising are materially hotter than the land and ocean are on either side of it. Now, how much hotter are the air and the land under the belt of rains and calms, upon Hindoostan, or Africa, or South America, where the former is supposed to be acquiring heat and expansion so rapidly, and to be ascending, than under, and in the dry belts on either side? None; it is cooler by the thermometer--much cooler.

The central belt of rains in midsummer over Africa, extends up as far as 17 deg. north latitude, and perhaps further. North of this line over the whole surface of the desert, the Barbary States, a part of the Mediterranean, and some portion of Italy, the dry season extends, and from the entire surface the N. E. trade blow into the central belt. Over the desert they all pass. Now this desert is a sea of sand, under a vertical sun, intensely heated, blistering the skin with which it comes in contact, and often acquiring a temperature of 150 deg. to 160 deg. of Fahrenheit. Under the central belt of rains neither the earth nor air exceed the temperature of 84 deg.. And yet the hot air of the desert does not ascend, but blows into this cooler central belt; and when it is felt as it blows off the western coast by the mariner, or even in Guinea, when the belt of rains has gone south in winter, as it often is as the harmattan, it is suffocating and intolerable. There, then, not only is it untrue, that the land and the air over it under the rainy belt are hotter, but it is true that intensely heated air blows horizontally from the Desert of Sahara. Nay, as it will appear in the sequel, this hottest of all surfaces not only can not have a vortex, but it can not induce a monsoon, and scarcely a sea breeze. The same is true in a great degree of the surface, and the air over it, on either side of the supposed vortex of the rainy belt upon South America. See the description of Humboldt, already given, where the thermometer stood as high as 115 deg. of Fahrenheit in the shade, while the N. E. winds, the regular trades, were blowing over the land. And it is equally true of Arabia, and indeed of every portion of the earth. There is not a spot upon the globe where the land and the air are cooler by the side of the central belt of rains, than under it. And the opposite is true every where upon the land.

How much hotter is the ocean and air under this supposed vortex? But little hotter than they are on the side where the sun is not vertical, and none on the other. Let us be a little more particular. The temperature of the Atlantic under the belt of rains in our winter, and on the south of the belt at the latitude of 3 deg. south, and down to 9 deg. or more south, is 82 deg.. The air may range a degree, or possibly two, higher than the water at either point. On the north this difference is from nothing at the meeting of the trades and belt of rains, to about 4 deg. at their northern limit. This is too trifling to be worth one moment's consideration. It is less, far less than the difference between the water and air of the Gulf Stream which runs along our coast, and the adjoining waters and air over them. While on the south side of the belt of rains the difference is actually against the theory--and the same state of things is reversed in summer, when the sun is vertical at the north.

From the log of an intelligent shipmaster, found in the wind and current charts of Lieutenant Maury, I abridge the following, which will illustrate this. Captain Young in February, found the N. E. trades at about 17 deg. north latitude, with the water at 75 deg. and air at 76 deg., trade-wind N. E.

At 12 deg. 16' the water was 75 deg. the air 76 deg. wind N. E. Feb. 22d. 9 deg. 49' " 76-1/2 deg. " 77 deg. " N. E. " 23d. 7 deg. 13' " 78 deg. " 78 deg. " N. E. " 24th. no obs. " 79-1/2 deg. " 79 deg. " N. E., E. S. E. rain. " 25th. 3 deg. 10' " 81 deg. " 83 deg. " E. S. E. rain. " 26th. no obs. " 82 deg. " 82 deg. " S. E. to E. S. E. hazy, rain & sqs. " 27th. 2 deg. 24' " 82 deg. " 82 deg. " calm, with rain. " 28th. no obs. " 82 deg. " 82 deg. " calm rain. March 1st. 0 deg. 29' " 82 deg. " 82 deg. " E. S. E. sqs. rain. " 2d. 1 deg. 27' S. L. " 82 deg. " 82 deg. " S. E. sqs. rain. " 3d. 2 deg. 44' " 82 deg. " 83 deg. " S. E. & S. S. E. weather settled. " 4th. 4 deg. 17' " 82 deg. " 83 deg. " S. S. E. & S. E. fair weather. " 5th. 6 deg. 08' " 82 deg. " 84 deg. " S. E. fair wthr. " 6th. 8 deg. 08' " 82 deg. " 84 deg. " S. E. & E. S. E. fair weather.

Here the air was seven degrees colder at the extreme limit of the N. E. trades than in the center of the belt of rains, as it is, usually, in mid-winter, but not in summer. On the other hand, after he left the region of calms and rains, where the water and air stood with almost entire uniformity at 82 deg., on the 3d of March, and for three days thereafter, during which he was in the S. E. trades with fair weather, the water was the same as under the supposed vortex, viz., 82 deg., and the air rose to 83 deg. and 84 deg.! This is demonstration.

I also take from a letter of Lieutenant Walsh to Lieutenant Maury, relative to the cruise of the "Taney" the following, showing the warmth of the Gulf Stream compared with the adjacent ocean.

"We first crossed the Gulf Stream on the 31st of October; we struck it in latitude 37 deg. 22', longitude 71 deg. 26' as indicated by the temperature of the water, which was as follows:

8 A.M. water at surface 66 deg. 9 " " " 73 deg. 10 " " " 76 deg. 11 " " " 77 deg.

77 deg. was the highest temperature found in crossing at this time.

Re-crossing it in May, in latitude 35 deg. 30', longitude 72 deg. 35', he found the water as follows:

8 A.M. water at surface 71 deg. 8' 9 " " " 73 deg. 10 " " " 75 deg. 5' 11 " " " 78 deg. 5' 12 M. " " 78 deg. 5'

79 deg. being the highest temperature found."

The average difference between the temperature of the water of the Gulf Stream and the adjoining ocean, at the line of division, is about ten degrees, increasing to more than twenty on approaching the coast, and within one hundred miles--a far greater difference than is ever found on the winter side of the inter-tropical rainy belt.

It is not only not so, then, that the surface of the ocean is materially warmer under the belt of rains than the adjoining surface under the trades, especially on the summer side, but if it were so, the trades would not be created thereby, any more than upon the Gulf Stream. And the opposite is true of the land where the line of calms, and rains, and drought meet, all around the globe. The fact assumed is therefore untrue. The hottest surfaces, even at the rainless portion, where there is no vortex, no storm, and no wind but the continual uniform N. E. horizontal trade-wind, never created, by reason of the heat alone, a mile of wind, a storm or shower.

But, again, the belt of calms, where the air is supposed to rise and create a suction which draws the trades on either side a distance of from one thousand to two thousand miles, an average of three thousand miles in all, at least, is not itself, on an average, over five hundred miles in breadth from north to south. What a wonder of meteorology is here!

With a breadth of five hundred miles, the rising of the atmosphere is supposed to be so rapid and of such immense volume that it draws the surface atmosphere, one thousand to fifteen hundred miles on one side and two thousand on the other, with a uniform steady velocity of twenty miles per hour. Is this vast suction found by the unlucky mariner who may be drawn within the vortex? Not at all. He finds no rapid suction there, but horizontal currents, not steady, indeed, like the trades, and sometimes calms at the center, but still the currents are there, and, except near the center, there as squalls, showers, and baffling winds and as monsoons.

Again, is there at the mouth of this vortex, or as you approach it, an increased rapidity in the trade corresponding to the magnitude of its influence? Does the trade become a hurricane as it approaches the spot where it is to supply the place of that which has suddenly "expanded by heat, and been forced to rise, boil over, and run off at the top in turn?" Not at all. It blows gently, even up to the very line of the rainy belt, and becomes squally and baffling, falls gradually calm near the center, or changes to a monsoon.

But, again, the belt of rains is so far from being a belt of calms strictly, that its monsoons in the Indian, Atlantic, and Pacific Oceans, at times, extend hundreds of miles out over the ocean. That of the Atlantic, triangular, with its base resting on Africa, according to Lieutenant Maury, extends sometimes almost to the coast of South America, a distance of one thousand miles, and thus under the supposed ascending vortex. Where is the great uprising suction during the prevalence of this extensive surface horizontal monsoon beneath it? Manifestly it does not exist. Nay, that monsoon is blowing from the warm current which sets up from the Cape of Good Hope toward the Caribbean Sea, and over the cold north polar current, which runs down between the continent and the Cape de Verdes. Equally untrue is the presumption that the air rises over heated portions of the earth elsewhere, and by reason of such heating. Perpendicular currents of the atmosphere are rarely seen, never extensive, or attaining any considerable altitude. I have watched for them thirty years. I have seen currents of air ascend, with their moisture condensing as they ascended, and unite with the under surface of a highly electrified cloud--the advance condensation of a thunder shower--but that cloud was moving horizontally at a distance of from one to two thousand feet above the surface of the earth, and did not rise. I have seen patches of scud rising from the surface during the intervals of a showery and highly electrified storm, toward, and uniting with, the clouds above, when very low, as I have seen them approach and unite horizontally; and doubtless there is a tendency upwards of the wind, created and attracted by the summer shower, as may be seen in the ascending dust before the rain, but I have never been able to detect an ascending current, except as induced and attracted by a cloud above moving horizontally, in the hottest day or dryest time. None of the clouds of our climate, even when the earth is heated and parched by a two months' unbroken drought, can be detected rising above the strata in which they form. I have watched the cumuli at such periods when they filled the air, and can assert that they never rise. The atmosphere moves, invariably, in horizontal strata, and the whole theory of ascending currents is fallacious.

But let us look still further at the tropical currents. The true harmattan of north-western Africa (for the term is sometimes misapplied), hot and blistering, generated upon the sand of the desert--why does it blow from Sahara horizontally, on or over cooler surfaces, following the belt of rains as a N. E. trade? Why does it not ascend? The sirocco of north Sahara, the kamsin or chamsin of eastern Sahara, and the simoon of Arabia, which blow hot and suffocating from those deserts--why do they blow from heated surfaces and horizontally over cooler ones? Why do they not ascend? Arabia is surrounded on three sides by seas and gulfs, from which evaporation is rapid. Her interior deserts are extensive and intensely hot--why are they rainless? Why do they not have a vortex, a monsoon, or even a shower? Because there is no such law or action as this theory supposes. Those winds blow horizontally in obedience to other laws, and under the control of other and more powerful agents. But further still, what heating and ascending process is it that makes the variable winds north of the tropics? that brings in the warm air and fog of the Gulf Stream upon our snow-clad coast, in mid-winter, to increase the January thaw? Nay, what heating process is it that disturbs the calms of the polar regions with fresh breezes and gales, sometimes of the force of 6, when the sun does not shine, the thermometer is from 20 deg. to 40 deg. below zero, the earth and sea one frozen surface, and the hardy explorer dressed in furs, barely lives in his cabin covered by an embankment of snow, and heated by a stove?

Gentlemen, meteorologists, it will not do. The theory is unsound; the assumed facts do not exist. The whole universe has not an agent, organic or inorganic, which can play such absurd and inconsistent pranks in the face of its Creator, as your various and complicated theories assign to caloric.

Away with the theory and all its incidental and complicated and mystified hypotheses, they rest like a pall upon the science;--away with the whole system, and let us seek some agent whose power and adaptation correspond with the extent, and simplicity, and magnificence of the phenomena, and, in some degree, with the power and wisdom of their Author.