Читать книгу A Book of the United States - Various - Страница 27

Table of Contents

THE United States are most desirably situated. Placed in the northern temperate zone, they occupy just that portion of it, which is most likely to yield a healthy climate and rich soil. Happily removed from the parching heat of the torrid, and eternal frosts of the frigid zone, the republic is nevertheless of such an extent as almost to touch upon both. The climate of a country, stretching through twenty degrees of latitude, cannot but be of great diversity. In this respect it has been divided into five regions, which may be denominated the very cold, the cold, the temperate, the warm, and the hot.

1. The very cold, in the north-east, may be defined by running a line from St. Regis, on the St. Lawrence, along the high land in the state of New York to Tioga Point, in Pennsylvania; thence to Stony Point on Hudson’s river, and thence to Cape Cod in Massachusetts. In this region the summers continue from June through August, and the winters from November to the middle of April. The extremes of heat and cold are great, and the changes sudden, but the country is, notwithstanding, healthy. To the westward, north of a line drawn from the southern extremity of Lake Huron to the Rocky Mountains, the climate is also very cold, and the northern extremity in the winter is excessively so.

The winters of Maine are long and severe, with clear settled weather, which generally continues from the middle of December, till the latter end of March; during which time, the ponds and fresh water rivers are passable on the ice. There is scarcely any spring season; the summer is short, and warm; but autumn is in general pure, healthy, and pleasant.

The climate of New Hampshire is highly favorable to health; but the winters are long and severe. Cattle are housed about the first of November. Snow lies on the ground from four to five months, and the use of sleighs during that period is general. The spring is rapid, and the heat of summer great, but of short duration; autumn is very pleasant. Morning and evening fires are needed as early as the first of September, and as late as the first of June.

The climate of Vermont differs little from that of New Hampshire, and is extremely healthy. The earth is generally covered with snow from the middle of December till the end of March; but the winter seasons may be said to continue from the beginning of November till the middle of April, during which, the inhabitants enjoy a serene sky and a keen cold air. The ground is seldom frozen to any great depth, being covered with a great body of snow, in some high lands to the depth of four or five feet, before the severe frosts begin. In this way the earth is enriched and moistened, and in the spring vegetation advances with great rapidity.

The climate of Massachusetts is perhaps more variable than that of any other of the New England states; not having the steady winter cold of those to the north, nor the general mildness in summer of those immediately south. Fires are necessary from November to May; and there are days, even in June, when they are not only comfortable, but indispensable for comfort. Cattle are housed in November. In winter, travelling is not often impeded by great falls of snow; though heavy and severe snow storms occur. The rivers and ponds are frozen three months in the year; and the harbors are usually closed a week or fortnight, and sometimes for a much longer time. As there are many cold days in summer, so also there are many warm days in winter; and the field which is at night soft enough to receive the plough, may be chained with frost and buried in snow before morning. Winter sets in late; frequently not till December, but, recently, it has gone quite through the spring months. Indeed, the most disagreeable portion of the year, is during March and April and part of May, when the east are prevailing winds. In autumn there is much weather truly delightful. Apples and pears flourish well in Massachusetts, peach trees sometimes suffer from the late spring and the early autumnal frosts. It is difficult to find an accurate description of so variable a climate; as no tolerably correct account of it could be given, except in the details of a meteorological table.

The climate of Rhode Island and Connecticut does not differ very materially from that of Massachusetts. In the southern parts of these states, summer may set in a few days earlier, and the winter be generally a little more temperate, but the change of climate is slight.

In the very cold tract are included the eastern and northern parts of New York, being the mountainous country, and the region lying to the east of it. Here the winters are long and severe, being more so as you proceed to the north. The climate of this region may be generally described as similar to that of the New England states, which lies in the same latitude. In the parts of Michigan territory, lying within this region, the climate resembles that of Canada.

In the region we have called very cold, the range of the thermometer is from thirty degrees below zero to ninety-eight above it; including great extremes both of heat and cold.

2. The cold region comprehends a great and very unequal range of country. In the eastern division it extends from the foregoing line, to Lakes Ontario and Erie, westward; and south, on the Atlantic coast, to about Cape Henlopen on the Delaware. Hence a line may be protracted to Washington, and along by the foot of the first mountains in Virginia to about Morgantown, North Carolina; thence through the mountains to Kenaway river, and north-east on the west side of the mountains to the upper part of Chesnut Ridge, in Pennsylvania. In the westward, the southern boundary of the very cold region before-mentioned, may be assumed as the northern boundary of the cold; and the southern boundary of the cold may be protracted westward from the head of Chesnut Ridge to the high lands, dividing the waters falling into the Ohio from those falling into the great lakes, and along in a northern and western direction, crossing the Mississippi about thirty miles below Praire des Chiens, thence south and west, crossing the Missouri about thirty miles below the Platte river; thence southward to the west of the Great Osage village, and then eastward to the Arkansas river, above the Hot Springs. In this division the winters commence in December and end in March, and the heat of summer commences in May and ends in September. The heat and cold here also go to great extremes; but the weather is very changeable, particularly in winter, so that neither severe heat nor severe cold lasts long at a time. The country in this division is also generally healthy.

In this division are comprehended the south-eastern and western parts of New York, New Jersey, the northern and eastern parts of Pennsylvania, most of Delaware and Maryland, the central and mountainous parts of Virginia, the southern portion of Michigan territory, the northern extremities of Ohio, Indiana, and Illinois, and portions of the Missouri and Arkansas territories.

In the south-eastern parts of New York the prevailing winds, during the summer, are southerly; the weather is variable, and the change of temperature sudden and frequent. The mild and damp sea air penetrates far inland; indeed, as far as the Highlands, the climate differs little from that of the seacoast. In the parts of New York west of the mountains, the average temperature is about three degrees higher than in the same latitude farther east. South-westerly winds prevail through most of the year; and the chill easterly wind is nearly unknown.38

The climate of Pennsylvania is very various. On the east side of the Alleghany Mountains it differs little from that of Connecticut. It is, like the other countries east of the mountains, subject to great and sudden changes; but on the west side, it is much more agreeable and temperate, with a greater portion of cloudy weather, and winters milder and more humid than on the Atlantic. The winter season commences about the twentieth of December, and the spring sets in about two weeks earlier than in the eastern parts of New York. There is frost almost every month in the year in some places, and the extremes of heat and cold are considerable. The keenness of the north-west wind in winter is excessive, but the state is, upon the whole, extremely healthy, and numerous instances of longevity occur.

The climate of New Jersey is dissimilar in different sections of the state. In the northern parts, there is clear, settled weather, and the winters are exceedingly cold; but the whole is very healthy. In the districts towards the south, particularly near the extremity, the weather approaches more nearly to that of the southern states, and is subject to very sudden changes. The climate of Delaware is much influenced by the face of the country; for the land being low and flat, the waters stagnate, and the inhabitants are consequently subject to intermittent fevers and agues. The northern parts, however, are much more agreeable and healthy than those to the south.

Among the mountains of Virginia the summers are delightful, and the heat is never found to be so oppressive as it is in the Atlantic districts; the winters are so mild in general, that snow seldom lies three days together on the ground. The salubrity of the climate, also, is equal to that of any part of the United States; and the inhabitants have, in consequence, a healthy, ruddy appearance. Perhaps there is no part of North America possessing a more agreeable climate, than that section of Virginia which lies west of the Blue Ridge; and, in particular, the fertile county of Bottetourt, which is entirely surrounded by mountains. Here the frost in winter is regular, but not severe. In summer the heat is great; but there is not a night in the year that a blanket is not found comfortable. Before ten o’clock in the morning the heat is greatest; at that hour a breeze generally springs up from the mountains, and renders the air agreeable the whole day. Fever and ague are disorders unknown here, and persons who come hither afflicted with them from the low country, get rid of them in a very short time. Except in the neighborhood of stagnant waters, Virginia has, upon the whole, a healthy climate.

The climate of Maryland is various in different districts, but for the most part mild and agreeable, well suited to agricultural productions, and particularly fruit trees. The eastern parts are similar to Delaware, having large tracts of marsh, which, during the day, load the atmosphere with vapor, that falls in dew in the close of the summer and autumn, which are unhealthy, and during which the inhabitants are much exposed to fever and ague. In the interior hilly country the climate improves very much, and among the mountains it is delightful and healthy; the summers being cooled by fine breezes, while the winters are tempered by a southern latitude, which renders them much milder than to the northward.

In the southern portions of Michigan territory, the winters are not severe, and the spring sets in as early as in any other part of the state which lies in the same latitude. In 1820, at Detroit, the mean heat of December was twenty-seven degrees, and of July sixty-nine. The temperature of this territory is rendered milder by the neighborhood of such large bodies of water, and by the absence of great elevations. The portions of the Missouri and Arkansas territories, that lie within the boundaries of the cold region, partake of the character of the climate already described. As the country in these territories is open and generally level, the temperature depends chiefly on the latitude.

The northern and north-eastern parts of Illinois are cold in the winter; the air from the great lake is chill and bleak, and sensibly affects the country exposed to its influence. In the region of Ohio, sloping towards the lakes, the snow falls to a very considerable depth, and lies long; sleighs and sledges are much used. The transitions during the winter are violent and frequent. That part of Indiana contiguous to Lake Michigan is often exposed to heavy falls of rain, and is consequently marshy and unhealthy.

3. The temperate region is situated between the cold, and a line drawn from Morgantown, North Carolina, south-westward along the foot of the mountains to their termination in Georgia, thence in a north-west direction by Florence, in Alabama, and crossing the Mississippi river about the upper part of the Chickasaw Bluffs, thence north-west to the Delaware towns on White river, and thence south-west to the Arkansas, above the Hot Springs. The region described within these limits lies in the very heart of the country, the whole being on a considerable elevation. It comprehends Kentucky and Missouri, with nearly the whole of Ohio, Indiana, Illinois, and Tennessee, the south part of Pennsylvania, the western part of Virginia, and small portions of North Carolina, Georgia, and Alabama. This climate is distinguished from the foregoing by an earlier spring, and by greater serenity, and fewer changes.

The climate of Tennessee forms a medium between the warmth of the south and the cold of the north; it may be correctly viewed as the middle climate of the United States, and proves peculiarly congenial to northern constitutions. There is no country in America where diseases are so rare, where physicians have so little practice, and where children are more robust and healthy. Snow falls in winter, and sometimes to a considerable depth; but the summer, particularly in the higher ground, is mild, and accompanied with excessive heat. Apples, pears, and plums are raised here in great perfection; and in sheltered situations it is thought that the fig might be cultivated to advantage. Maize is planted early in April; cotton is the staple of agriculture. Within the limits of this state, most of the forest trees of the western country are found in abundance.

In Kentucky the climate is not so mild as that of Tennessee. It is however mild and temperate. Grape vines flourish here of prodigious size. All the grains, pulses, garden vegetables, and fruits of the temperate climate abound. The wheat of Kentucky is excellent, but hemp and tobacco are her staples.

The climate of Missouri is temperate, though variable. Winter continues in its severity for about two months, from the latter part of December to the last of February; but even during this interval there are many warm and pleasant days. Snow seldom remains on the ground more than sixty hours; and its maximum depth is generally about six inches. Frequently the rivers are for weeks frozen sufficiently hard for the passage of loaded teams. Trees sometimes blossom in March, and the spring months with occasional cold, have days as pleasant as those of summer. From the sandy and warm texture of the soil, and the openness of the country, the heat in summer is very great, and would be oppressive, except for the prevalence of agreeable breezes. Another characteristic of the Missouri climate, is its extreme dryness; evaporation is rapid, and the average amount of rain falling in the year is estimated at eighteen inches. Long and steady rains so common in the eastern states, seldom occur; the summer rains are generally thunder showers. The autumn months are delightful, serene, temperate, and salubrious.

The part of Ohio lying within this division of climate is moderate in respect to climate; suffering neither from excessive cold or the reverse. Along the banks of the Ohio river it is more mild than in the central and mountainous regions; and the difference is owing to the difference of latitude and elevation. The winters vary in severity, being sometimes quite mild; in other years the rivers are frozen for eight or nine weeks. Severe cold generally continues from the last week in December through the first in February. Summer heat in the valley of the Ohio is oppressive, but of short duration. Autumn is temperate, pleasant, and healthy. Nowhere in the world, says Mr. Flint, is the grand autumnal painting of the forests, in the decay of vegetation, seen in more beauty than in the beech forests of Ohio. The richness of the fading colors, and the effect of the mingling hues baffles all description. On the whole, a great farming community, like that of Ohio, could scarcely desire a better climate for themselves, their cattle, and stock of all kinds; or one, in which a man can work abroad, with comfort, a greater number of days in the year.

Indiana has much the same temperature with Illinois and Missouri. The winters are mild, and seldom last in their severity more than six weeks; during this period, the slower streams are generally frozen, and afford a safe passage on the ice. In the middle and southern parts of the state snow seldom falls to a greater depth than six inches. Trees begin to be green early in April, and the peach blossoms in March. A large number of shrubs put forth their flowers before the leaves, and from this the spring vegetation is singularly beautiful. Illinois has in general the same climate with Missouri, and its productions are the same as those of that state; being, however, somewhat lower, it is more subject to inundation, and consequently the air is more humid. The portions of Pennsylvania, Virginia, North Carolina, Georgia and Alabama, comprehended within this division, partake the general character of climate with those we have particularly described.

4. The region possessing a warm climate lies between the temperate, and a line drawn from Cape Henry in a circular direction, and passing above Tarboro, and through Fayetteville, Columbia, Augusta, Milledgeville and Fort Jackson in Alabama, and thence a little south of west across the Mississippi, and on to the Sabine river, in the latitude of Nacogdoches, in Texas. In this region the winters continue from about the first of January to the first of March; and the summers from the first of May to the middle of October. The weather is pretty settled and steady, and, except in swampy or marshy situations, the country is generally healthy. This region includes the interior and central parts of North Carolina, the northern and western parts of South Carolina, the northern parts of Georgia, Alabama, Mississippi, and Louisiana.

In the northern and western parts of South Carolina, the land is mountainous, and the climate generally salubrious. The air is dry, and in winter cold; but it is generally mild and delightful. The highlands of North Carolina that lie within this district are healthy and pleasant; the days in summer are hot, but the nights are refreshed by cool breezes. The northern and hilly region of Georgia is as healthy as any part of the states. Winter continues from the middle of December to the middle of February. The northern parts of Alabama, in the districts of hills, springs, and pine forests, are generally healthy. In winter the still waters often freeze; and the summers are not much hotter than they are many degrees farther to the north.

The climate of the northern part of Mississippi, in places removed from stagnant waters, is healthy. Heat in summer is intense; and during the latter month of that season and the first of autumn, even the residents in the healthy districts are exposed to severe bilious attacks. In compensation, however, they are free from the pulmonary affections which occasion so much destruction in the more northern regions. The productions of this state are the same with those of Louisiana.

5. The hot region extends from the southern extremity of the warm, to the Atlantic Ocean, and the Gulf of Mexico. It comprises all Florida, and the southern parts of the Carolinas,39 Georgia, Alabama, and Mississippi, with the greater portion of Louisiana.

The climate of Florida may be considered in some respects as a tropical climate. From the first of July to the first of October, the air is sultry, and the heat exceedingly oppressive. This may be considered the unhealthy season, during which fevers are prevalent, but even at this time the climate of St. Augustine is salubrious and pleasant, and is a place of resort for those who are desirous of avoiding sickness. During this period the range of the thermometer is between eighty-four and eighty-eight degrees, and it sometimes rises above one hundred. Even in winter, the influence of the clear vertical sun is always uncomfortable; in the peninsular parts, water never freezes, though there are sometimes slight frosts. In this climate the most delicate orange trees flourish and bear delicious fruits; the air is generally pure and mild, and the breeze pleasant. Heavy dews fall, and the night air is exceedingly humid. The rainy season commences early in winter; in February and March there are severe thunder storms by night, followed by days of great clearness and beauty. The peninsula is visited by tornadoes, and at the time of the autumnal equinox, hurricanes and destructive gales occur.

In the southern and eastern portions of the Carolinas, the summers are very hot, sultry, moist and unhealthy. The extensive and rapid decomposition of vegetable matter engenders exhalations, which unite with the miasmata of the swamps, and create an atmosphere loaded with the most deleterious qualities. Intermittent and bilious fevers are frequent and severe. In the low country the summer lasts seven or eight months; and though the winter frost is sometimes severe enough to kill the tender plants, it seldom lasts more than three or four days, or penetrates the ground above two inches. Spring commences about the middle of February, and green peas are often in the market by the middle of March; but the weather varies very much till about the first of May, when it becomes steadily warm, and continues increasing in heat till September, when it begins to moderate. Almost every person whose circumstances permit, removes to a more healthy situation during this period, and a vast number go to the northern states in the summer, and return in the fall. The period of going north is mostly from the middle of May to the middle of July, and of returning, from the middle of October to the middle of November. The anxiety that prevails during that period is extreme, and when it is over, the inhabitants congratulate one another with the full prospect of ten or eleven months being added to their lives.

The climate of Georgia differs little from that already described of the Carolinas. The rice swamps, and the low country in general, are very unhealthy, and the planters are obliged, during the sickly season, to retire to the elevated parts of the state. A near approach to the tropical temperature is found in some portions of Georgia, where the cane, the olive, and sweet orange flourish luxuriantly. The climate of the southern part of Alabama, and of Mississippi, resembles that of Georgia and South Carolina in the same latitudes. In the thirty-first degree of latitude, the thermometer stands in spring water at sixty-nine degrees, which is nearly the mean temperature of the year. A series of thermometrical observations is mentioned by Mr. Flint, which gave the following result. The warmest part of the warmest day in April, gave eighty-two degrees; mean heat of July of the same year, eighty-six; coldest in January, fifty-four; coldest in February, forty-three; warmest in March, eighty-five degrees. In the same year, trees even in swamps, where the vegetation is most tardy, were in full leaf by the second of April; at which time peach blossoms were gone. Peas were in pod by the twelfth of April; when peaches were of the size of a hazel-nut, and the fig trees in full leaf. Green peas were on the table, and strawberries ripe by the second of May, and on the sixteenth of the same month, mulberries, dewberries, and whortleberries were ripe.

The climate of Louisiana bears a general resemblance to that of Florida. All the northern fruits come to perfection here, with the exception of apples. The pumpkin and melon tribe flourish, and the common garden vegetables are cultivated in abundance. Figs of different kinds might be extensively raised for exportation, but are much neglected. On the rich alluvial lands maize thrives wonderfully; but wheat and rye do not flourish. In the region of the sugar-cane, along the whole shore of the gulf, and on the lower courses of the rivers of Louisiana, the orange tree flourishes and bears a delicious fruit. In the year 1822, a severe frost destroyed these trees while in full bearing, but the roots have thrown out new trees. The cultivated grape, and various wild grapes abound. Berries are neither common nor good. Cotton grows to the height of six feet; and tobacco of the first quality is extensively raised.

In addition to the views of climate already given, we may add the following description of that of Mississippi Valley, for which we have been indebted to the industrious observation of Mr. Flint. ‘We may class four distinct climates, between the sources and the outlet of the Mississippi. The first, commencing at its sources, and terminating at Prairie du Chien, corresponds pretty accurately to the climate between Montreal and Boston; with this difference, that the amount of snow falling in the former is much less than in the latter region. The mean temperature of a year would be something higher on the Mississippi. The vegetables raised, the time of planting, and the modes of cultivating them, would, probably, be nearly the same. Vegetation will have nearly the same progress and periodical changes. The growing of gourd seed corn, which demands an increase of temperature to bring it to maturity, is not planted in this region. The Irish potatoe is raised in this climate in the utmost perfection. Wheat and cultivated grasses succeed well. The apple and the pear tree require fostering, and southern exposure, to bring fruit in perfection. The peach tree has still more the habits and the fragile delicacy of a southern stranger, and requires a sheltered declivity, with a southern exposure, to succeed at all. Five months in the year may be said to belong to the dominion of winter. For that length of time, the cattle require shelter in the severe weather, and the still waters remain frozen.

‘The next climate includes the opposite states of Missouri and Illinois, in their whole extent, or the country between forty-one and thirty-seven degrees. Cattle, though much benefited by sheltering, and often needing it, seldom receive it. It is not so favorable for cultivated grasses, as the preceding region. Gourd seed corn is the only kind extensively planted. The winter commences with January, and ends with the second week in February. The ice, in the still waters, after that time thaws. Wheat, the inhabitant of a variety of climates, is at home, as a native, in this. The persimon and the papaw are found in its whole extent. It is the favored region of the apple, the pear, and peach tree. Snows neither fall deep, nor lie long. The Irish potato succeeds to a certain extent, but not as well, as in the former climate; and this disadvantage is supplied by the sweet potato, which, though not at home in this climate, with a little care in the cultivation, flourishes. The grandeur of vegetation, and the temperature of March and April, indicate an approach towards a southern climate.

‘The next climate extends from thirty-seven to thirty-one degrees. Below thirty-five degrees, in the rich alluvial soils, the apple tree begins to fail in bringing its fruit to perfection. We have never tasted apples worth eating, raised much below New Madrid. Cotton, between this point and thirty-three degrees, is raised, in favorable positions, for home consumption; but is seldom to be depended upon for a crop. Below thirty-three degrees commences the proper climate for cotton, and it is the staple article of cultivation. Festoons of long moss hang from the trees, and darken the forests. The palmetto gives to the low alluvial grounds a grand and striking verdure. The muscadine grape, strongly designating climate, is first found here. Laurel trees become common in the forest, retaining their foliage and their verdure through the winter. Wheat is no longer seen, as an article of cultivation. The fig tree brings its fruit to full maturity.

‘Below this climate, to the gulf, is the region of the sugar-cane and the sweet orange tree. It would be, if it were cultivated, the region of the olive. Snow is no longer seen to fall, except a few flakes in the coldest storms. The streams are never frozen. Winter is only marked by nights of white frost, and days of north-west winds, which seldom last longer than three days in succession, and are followed by south winds and warm days. The trees are generally in leaf by the middle of February, and always by the first of March. Bats are hovering in the air during the night. Fireflies are seen in the middle of February. Early in March the forests are in blossom. The margins of the creeks and streams are perfumed with the meadow pink, or honeysuckle, yellow jessamine, and other fragrant flowers. During almost every night a thunder-storm occurs. Cotton and corn are planted from March to July. In these regions the summers are uniformly hot, although there are days when the mercury rises as high in New England, as in Louisiana. The heat, however, is more uniform and sustained, commences much earlier, and continues much later. From February to September thunder-storms are common, often accompanied with severe thunder, and sometimes with gales, or tornadoes, in which the trees of the forest are prostrated in every direction, and the tract of country, which is covered with the fallen trees, is called a ‘hurricane.’ The depressing influence of the summer heat results from its long continuance, and equable and unremitting tenor, rather than from the intensity of its ardor at any given time. It must however be admitted, that at all times the unclouded radiance of the vertical sun of this climate is extremely oppressive.—Such are the summers and autumns of the southern divisions of this valley.

‘The winters, in the whole extent of the country, are variable, passing rapidly from warm to cold, and the reverse. Near the Mississippi, and where there is little to vary the general direction of the winds, they ordinarily blow three or four days from the north. In the northern and middle regions, the consequence is cold weather, frost more or less severe, and perhaps storm, with snow and sleet. During these days the rivers are covered with ice. The opposite breeze alternates. There is immediately a bland and relaxing feeling in the atmosphere. It becomes warm; and the red-birds sing in these days, in January and February, as far north as Prairie du Chien. These abrupt and frequent transitions can hardly fail to have an unfavorable influence upon health. From forty to thirty-six degrees the rivers almost invariably freeze, for a longer or shorter period, through the winter. At St. Louis on the Mississippi, and at Cincinnati on the Ohio, in nearly the same parallels, between thirty-eight and thirty-nine degrees, the two rivers are sometimes capable of being crossed on the ice for eight weeks together.

‘Although the summers over all this valley must be admitted to be hot, yet the exemption of the country from mountains and impediments to the free course of the winds, and the circumstance, that the greater proportion of the country has a surface bare of forests, and, probably, other unexplained atmospheric agents, concur to create, during the sultry months, almost a constant breeze. It thence happens, that the air on these wide prairies is rendered fresh, and the heats are tempered, in the same manner, as is felt on the ocean.’

The annual and mean quantity of rain that falls in the United States is much greater than in most countries of Europe, certain mountainous regions and heads of gulfs excepted. This has been ascertained by numerous and accurate observations made on different parts of the Atlantic coast. It is said, on the authority of tabular views, that, on a medium, one third less rain falls in Europe than in the United States; yet Dr. Holyoke mentions, in his memoir on the climate of the United States, twenty cities in Europe, which, at a mean of twenty years, have had one hundred and twenty days of rain; while Cambridge has had but eighty-eight days, Salem ninety-five days of rain, and Philadelphia seventy-six days, at a medium of twenty years. The mean annual quantity of rain at Philadelphia is very little more than the mean annual quantity at Glasgow for a term of thirty years preceding 1790. The above greater quantity of rain, in fewer days, in America, indicates the rain to be much heavier there than in Europe. On the other hand, it is equally well ascertained, that the evaporation of these rains proceeds much quicker in America than in Europe; and that, consequently, the air is habitually drier, and less calm, unless Charleston be taken as an exception. It has been found, that the mean annual quantity of evaporation at Cambridge, near Boston, was fifty-six inches, for a term of seven years; while in seven German and Italian cities, on a mean of twenty years, the annual evaporation was forty-nine inches, or seven of difference; although the Italian cities are in a much more favorable situation for evaporation than the vicinity of Boston, adjacent to the Atlantic ocean. The same fact of greater evaporation was also observed to take place in Upper Louisiana, and along the higher Missouri, as far as the Rocky Mountains, by Captain Lewis.

The habitual dryness of the American climate increases, as we advance west and north-west from the Missouri, where there frequently is not a drop of rain for six months. This is owing to the great distance from any sea, the superior elevation, and the comparative want of timber, combined with the greater intensity and longer duration of the north-west wind, which sweeps with unobstructed force over the naked plains. It appears, then, that more rain falls in fewer days, in America, than in Europe; and that there are fewer cloudy days, more fair days, and quicker evaporation. It is to this last circumstance we must ascribe those immense dews, unknown in European climates, which occur in America, and which are so copious in summer, as to resemble heavy showers of rain. But it must also be observed, that dews are comparatively unknown in the tract watered by the Upper Missouri; and which, in all probability, is owing to the want of timber, wood being limited to the banks of the rivers, which are commonly bordered with trees.

GENERAL REMARKS ON CLIMATE.

It is the opinion of Professor Leslie, that all the varieties of climate are reducible to two causes; distance from the equator, and height above the level of the sea. ‘Latitude and local elevation form, indeed,’ says he, ‘the great basis of the law of climate, and any other modifications have only a partial and very limited influence.’

Climate is generally treated of under four divisions: the cold and humid; cold and dry; warm and humid; hot and dry. But these climates do not always exist according to the full import of the terms by which they are designated. They are subject to modifications, principally of two kinds; the one arising from the alternation of two different climates in the same region, the other from the greater or less prevalence of either of the four elements. Thus when heat, dryness, and humidity are duly combined, they render the climate comparatively temperate. In Egypt, for instance, the combinations of heat and humidity, during the inundation of the Nile, and of heat and dryness during the rest of the year, temper a climate, without which these alternations would be insupportable. In Holland the cold humidity of the autumn is succeeded by frost, which increases the salubrity of the climate, that would not otherwise be so healthy.

The sea exercises an important equalizing influence on the temperature of the globe. In the tropical regions a large extent of ocean spreads coolness on every side, and affords a perpetual succession of refreshing breezes. Islands are always, comparatively, of more temperate climates than continents, and those scattered over the expanse of the Pacific may be said to enjoy almost a perpetual spring. The influence of the winds is also very important; particularly that of the trade-winds. Blowing from east to west across the sands of Africa, the latter produce, on its western coast, a most intense heat, much greater than is experienced on the eastern. In passing the Atlantic they are considerably cooled; and though their temperature is again raised in traversing South America, yet, before reaching the opposite coast, they meet the tremendous snow-clad Andes, which stop their progress and diffuse a wide coolness.

Again, the mountain ranges of the earth not only present and retain on their sides a refreshing coolness, but, by the mighty rivers to which they give rise, diffuse a great amelioration of the temperature through extensive regions. They are particularly of this character, and give rise to the largest rivers in the torrid and burning zones of the earth. In the temperate climate, and those approaching to the poles, mountains are of moderate elevation, are almost always barren, and give rise to few considerable streams.

It appears probable that the climates of European countries were more severe in ancient times than they are at present. Cæsar says that the vine could not be cultivated in Gaul on account of its winter cold. The reindeer, now found only in the zone of Lapland, was then an inhabitant of the Pyrenees. The Tiber was frequently frozen over, and the ground about Rome covered with snow for several weeks together, which very rarely happens in our time. The Rhine and the Danube, in the time of Augustus, was generally frozen over for several months of winter. The barbarians who overran the Roman empire a few centuries afterwards, transported their armies and wagons across the ice of these rivers. Though the fact is well established, the causes of this change of climate do not seem to be satisfactorily explained.