Climate

CLIMATE. Climate affects the agriculturist, so far as the product of the soil is concerned, in an important degree; heat, rainfall, humidity, air currents, all operating for or against the fertility of the soil. The principal points collected from a variety of sources, as relating to the United States generally, are summed up as follows: The climate of the United States is a peculiar one. Most of it lies within the dry belt of the trade winds, which, in our summers, make the dryness of the California climate and of New Mexico, where the corn crop is dependent on irrigation. There are two of these dry belts, one on each side of the equator, and their dry winds blow diagonally into each other, producing by their mutual action a belt of rain about five hundred miles in width under the equator, and directly under the sun. These winds are concentrated by the lofty range of mountains in South America and Mexico, and turned northwards, carrying with them this belt of rains. In our summer they extend west as far as the middle of Texas; thence north, through the middle of Kansas; they curve gradually eastward and pass to the Atlantic by the line of the great northern lakes, covering all the old States with the rains from this equatorial belt; extending no further west than the middle of Texas and Kansas, they leave the western portions of them, to the dry California climate. These rains, fram causes not yet fully ascertained by science, ate irregular as to time, quantity' and duration,. In the spring they are more concentrated, giving us the heavy, beating rains of March and April, and in July and August they cease almost entirely. We have no rains from the evaporations of our country; these we see in the form of dew only or, at most, they, but slightly increase the amount of our equatorial rains. From this source of our rains results the extremes so peculiar to the American climate. At one time our ploughed lands are saturated with water, our clay soils are melted and, in drying out, are compacted, so as to be much harder than the frosts left them in spring, before they were broken up. Then quickly follow droughts, parching and baking the soil, malting it unfit, if worn, for profitable production. These influences of the climate so act upon the soil that the standing topics of our agricultural writers are drainage, thorough ploughing and constant stirring of the soil. The following tables show the rainfall at various points in the United States and also in Europe. They will be found an interesting study: These tables exhibit an average fall of rain during summer in California of 0.3 of an inch, and in the Atlantic States of thirteen inches nearly, and in European vine-growing countries of 7.7 inches. The climate of California would be more favorable if it had more rain in sum mer but, in moist situations, or where irrigation may be employed, it presents all that invites to grape production and, in fact, to the production of fruit generally. Stock also should be remu nerative, since the dry summer climate enables the grass to retain its nourishment even when dry. In the smaller cereal grains also, the yield is good; but Indian corn can not be successfully grown except where the soil may be irrigated. The climate of the Pacific coast of America is a peculiar one in many respects, and especially interesting to the Prof. E.'C. Merrick has compiled much valuable matter. in this direction, from which we extract as follows: The annual isotherm of 50° Fahrenheit passing through London, England, latitude 51° 30' north, is depressed southward more than 10° in crossing the Atlantic, striking the American coast near New York City, latitude 40° 42' north. The northern deflection of this isotherm on the Euro pean coast is obviously the result of the system of warm water currents springing from the Gulf Stream. These currents bear the heated waters of the tropical seas diagonally across the Atlan tic, ameliorating the rugged northern coast cli mates of Europe, and placing, them upon a par with opposite American coast climates, at least 10' further south. The same isotherm of 50° Fahrenheit passes nearly west across the Ameri can continent to longitude 103° west, where the elevation of the Rocky mountain plateau causes it to dip suddenly southward as far as the lati tude of Sante F:"..; thence crossing Rocky mountains westwardly it trends north*est, almost parallel with the Pacific coast to the north end of Vancouver's Island, latitude 51° 30' north, about the same northing as upon the European coast. Mr. Blodgett's later examination of the meteor:' ological observations made in Alaska by the Rust sian government during a series of years, presents remarkable confirmations of the northward ten dency of the isotherms on our western coast. The annual isotherm of 40° Fahr., coasting ward through the southern part of the Aleutian islands, bends rapidly southward on approach ing the Asiatic coast. Maury, in his Physical Geograp.,y of the Sea, indicated the cause of thiS isothermal elevation in a system of warm-water, currents, similar to the Atlantic Gulf Stresm; and its branches. Only the rudimentary points of the Pacific system of currents were then known ; but Maury's theory has since been amply verified by later and very careful observa tion. Captain Kerhailet, of the French imperial navy, in his General Examination of the Pacific Ocean, has clearly traced the analogue of the Atlantic Gulf Stream in the Japan current, of navigators, called by the Japanese, themselves, Kuro Siwo, or black stream, from its dark color, in which, as well as in other remarkable points, it strongly resemblesjts Atlantic congener.. This Japanese current, or Kuro Siwo, results from two currents of heated water from the Indian ocean, one passing through the straits of Malacca and the China sea, and the other skirting the eastern coast of the Philippine islands, at the northern extremity of which they unite opposite the Japan islands; this united current again divides its main branch, trending east-northeast, and strikes our Pacific coast about midway between Vancou ver's Island and Sitka Island. The waters of the current near its southern edge, latitude 12° 20' north, longitude 163° 20' west, were found by M. De Tessau, commander of the French frigate Venus, to be 4° 30' Fahrenheit hotter than those just outside the current; a difference which would have been much greater if the observation had been made with water from the main axial line of the current. The impact of the Kuro Siwo upon our western coast is more feeble, on account of the greater mass of intervening ocean water, than the impact of the Atlantic Gulf Stream upon the European coast, and conse quently it is less potential in directly elevating temperatures. But any deficiency resulting from this cause is amply compensated by the narrow ness of Behring's strait, through which a much smallervolume of floating ice and cold Arctic i waters is discharged than those immense masses of both which sweep down into the Atlantic, rapidly absorbing the heat brought up by the Gulf Stream. The projecting peninsula of Alaska, with its out-lying islands, also deflects far to the westward the reactionary arctic currents, and protects our western climates from their depressing influence. The southeast winds, laden with moisture from the tropical atmosphere of the ocean, prevail along the coast during the winter or rainy season. Their latent heat, set free by pre cipitation, combines with the general influence of the Kuro Siwo in elevating the temperature and and bending northward the isothermals. These fats are sufficient to show why Puget Sound is on a par with New York City, while British Co lumbia. and t le southern part of Alaska are found within the same climatic parallels as northern New York and New England. Another and very important difference between the climates of our Pacific coast and those of Europe is found in the comparatively narrow ran,ge of barometric and thermometric oscillation. These are but the scien tific expression of those conditions of majestic equability which first suggested the name Pacific, a name the significance and appropriateness of which become more striking as our knowledge of it increases For this very remarkable exception from extremes of variations our western coast is indebted to the great width of the Pacific ocean The hurricanes generated in that mighty cauldron of atmospheric forces, the Gulf Stream, are hurled across the narrower volume of the Atlantic with a force sufficient to be severely felt upon the coast of Europe. Storms entirely analogous, and accom panied by electric and calorific changes equally marked, prevail upon the Asiatic coast, and have been traced some distance along the Kuro t•iwo; but the mighty mass of the Pacific waters calmly absorbs their fury, and prevents their disturbing force from reaching our shores. The atmospheric changes of the Pacific coast are consequently more uniform and of minor range. Comparing the averages of winter and summer temperature along the isothermal line of 50' Fahrenheit, the varia .tions on the Atlantic coast are found to be double those on the Pacific. As a specimen of extreme variation a little further south, it may be stated that the mean range of winter temperature at San Francisco from the mean of July is only 8' 30' Fahrenheit, whereas the variation at Washington, D. C., is 44° 30' Fahrenheit, or more than live times as great. A still more prominent point of difference between our Pacific climates and those of Europe is found in the periodicity of rain. The arrangement of the year into two seasons, wet and dry, instead of four, is found only in the lower latitudes of Europe and Africa. On the Pacific coast it is observable, north of the Columbia river, as far as the forty-eighth parallel. Nearly all the rain of California falls between November and June. According to Blodgett's hyetal (relating to, or the distribution of, rain) charts, the annual fall of rain in that State is about twenty-two inches, decreasing southward to the Colorado desert, where it is almost nothing. In the northern p5rt of the State, and on the western slope of the Sierra Nevada, the range is stated at thirty-five inches per annum. The general average is about half that of the States east of the Mississippi. This average increases northward. At Humboldt it is about forty-five inches, and at Vancouver's Island about sixty-five inches per annum. At Port Townshend, on Puget Sound, the distinction between the wet and the dry season is practically obliterated, the fall of rain being distributed throughout the year. On Sitka Island it becomes excessive, the mean annual deposit being 89.90 inches. Coming now to the climate of the West and Northwest, east of the meridian near which Omaha is situated, we find a climate often intense ly cold or at least variable in winter, but with plenty of rainfall, equably distributed, and with summers of strong heat so the grape may be ri pened well up to and even into Minnesota. So the more prolific varieties of Dent corn, thrives as nowhere else in the world; also all cereal graius, sweet potatoes, tomatoes, egg plant, pepper. melons, and many other tropical and sub-tropical annuals. As a fruit growing region the prairie districts are not especially adapted thereto, yet with a little care many varieties adapted to the climate may be raised, and the timber districts are unsurpassed in the production of fruit, the peach and sweet cherries flourishing on the east shore of I ake Michigan, nearly to 45° north lati tude. West of Omaha the climate becomes dryer and dryer until passing the hundredth meridian, or the central part of Kansas, the climate becomes too dry in summer for general agriculture, or the successful cultivation of fruit and the cereal crops without irrigation, but is eminently adapted to pasturage. Further north there is more rain, so that, in the latitude of Minnesota, cereal crops may be raised in the valleys through to the Pacific coast. Some years ago, Mr. James Lippincott, of New Jersey, gathered together a mass of facts in relation to climate and vegeta tion, and the geographical distribution of vege table and, generally also, of animal life in the earth. A glance at this work shows that the geographical distribution of plants is a subject of vast extent and importance. The nature of the vegetation covering the earth varies, as we have remarked, according to the climate and locality; and plants are fitted for different kinds of soils, as well as for different amounts of temperature, light and moisture. From the poles to the equator this constant variation in the nature of the flora is a shifting scene, passing from the lichens and mosses (the lowest vegetable forms in the arctic and antarctic regions) to the noble palms, bananas, and orchids of the tropics by a series of regulated changes through all the mul tiform aspects of the vegetable kingdom. The same progress and graduated fitness is observed in the vegetation of lofty mountains under the equator, when descending from the summit to the base. From the scanty vegetation of Green land, where the only woody plants are the Arctic willows, trees scarcely a finger-length in height, we may trace the expansion of vegetation as we move southward over the lichens and mosses to the saxifrages and cruciferous plants, those resembling the cabbage and turnip in their mode of flowering; then to grassy pastures, and by coniferous or fir-like trees, and amen taeeous or birch and alder-like trees, to the north ern borders of the United States. Extending our glance further southward we shall perceive that we enter the region of oaks, hickory and ash, of tulip,(Liriodendron)cottonwood buttonwood wal nut, red and white cedars, sugar and other maples, sassafras, sumac, laurel, and many other trees and shrubs of the temperate regions of North Ameri ca. In the districts further south we find an increase both of species and of genera, and more tropical forms show themselves, such as mag nolia, Osage orange, honey loeuet, cypress, holly, bay, wax myrtle, the cotton plant, rice, the live oak, and enter the borders of the regions of the palmetto and the orange; thence to those of the sugar cane and pineapple, the coffee plant and the cocoanut, and the luxuriant vegetation of the equator and torrid heats. In this progress, as Humboldt, the father of geographical botany remarks, we find organic life and vigor gradu ally augmenting with the increase of temperature.

The numb,• of species continues to increase as we approach the equator, and each zone presents its own peculiar features; the tropics their vari ety and grandeur of vegetable forms; the north its meadows and green pastures, its evergreen firs and pines, and the periodical awakening of nature in the spring-time of the year, Many causes intimately connected with the aspects of our globe have an influence in modifying the conditions of climate, and thus affecting the dis tribution of animals and plants on its sur face. The geographical forms of contour, the relief or elevation and depression of the terres trial surface, the relations of size, extent, and position, each exert a very marked effect upon the climatic peculiarities of a district. The bearing or direction of the shores of a continent, the elevation of a mountain in one place rather than in another, the subdivision of a continent into islands or peninsulas, and other minor dif ferences, have very important bearings upon the climate of a district. The depression of a few hundred feet over some wide areas would reduce some regions to the level of the sea; or sink them beneath its waves, or so modify the climate of the higher portions left above the waters as to render them no longer tenable by the life that once enjoyed a congenial clime. This is shown by the observation that some low islands scat tered in clusters are covered with a vegetation entirely different from that of extensive plains, though lying in the same latitude. A change in the bearing of the shores would modify the cur rents of the ocean, which would react upon veg etation. Mountain-chains have oftentimes an influence upon the prevailing winds, and their height, or the plateaus from which they arise, modify the climate, and render it temperate or arctic under the fervent heats of the torrid zone. A mountain-chain extending from east to west may form a barrier between the colder regions on the north and the warmer on the south, and thus protect the northern plains from the warmer winds of more temperate regions, and increase the heat on the southern slope. This is exem plified by the Alps of Switzerland, which reduce the temperature, of Germany below the mean that ould otherwise prevail but for their cool ing influence. Under some of the high towers of this mountain-barrier against the assaults of winter, the palm, the pomegranate, the orange and the olive grow, in the open air, while a few miles to the eastward, in valleys open to the north, through which the hurricane-blasts of the Borra rush with terrific force and severity of , cold, often sweeping vessels from anchorage, these more tender plants can not exist. A few thousand feet in elevation, which is insignificant compared with the mass of the earth, changes entirely the aspect and the character of a- coun try. For evidence of this assertion we may compare the burning region of Vera Cruz—its tropical productions and its fatal fevers—with the lofty plains of Mexico, their temperate growths and perennial spring, or the immense forests of the Amazon, where vegetation puts forth all its splendors, and where animal life is abundantly prolific, with the desolate pararnos or Alpine regions of the summits of the Andes, rude, ungenial and misty, Or imagine the interior plains of the United States, east of the Rocky mountains, to be Blighty inclined towards the north, and the Mississippi river to empty into the Frozen sea or Arctic ocean, or into Hud son's Bay, and the new relations of warmth and moisture incident upon this single changy of direction of the current of this river wouldgfect the most important modifications in the condi tions of the vegetable and animal world, 'would exert a still greater influence upon the welfare of the inhabitants and, through them, upon the destinies of society yet to be, and perhaps, upon the entire human race. The climate that would result from latitude alone is greatly modified by the presence or absence of extended sheets of water; and the distribution of heat through the year, for any place, whatever, depends essentially on its proximity to, or its distance from, the ocean or large lakes, and the relative frequency of the winds that blow over them. The equaliz ing influence of large bodies of water, the tem perature of which is less liable to sudden changes than the atmospheric air, is quite apparent. While in Ireland and the southwestern part of England the myrtle grows in the open air, as in Portugal, fearless of the cold of winter, the sum mer sun of these ao genial isles does not succeed in perfectly ripening the plums and pears which , grow and ripen well in the same latitude on the continent. On the coast of Cornwall shrubs as delicate as the camellia and orange are green throughout the year in the gardens, though in a latitude at which, in the interior of the continent of Europe, trees the most hardy can alone brave the winter cold. The Mild climate of England can not ripen the grape almost under the same parallel where are grown the vines of the Rhine, nor will our Indian corn ever mature or attain there, even the size it will reach on our most northern border, even of Maine, or in Canada. In relation to the definite amount of heat required by plants, it appears that the conditions which define the limits of a plant require that we should know the degree of temperature at which its vegetation begins and ends; that at hich it will flower and will mature its seeds or fruit; and also the sum of the mean daily temperatures during these periods respectively. The hypothe sis that a definite amount of heat is required in order to develop each plant in its progress from one stage of growth to another was first advanced by Reaumer, better known in America from the thermometer which bears his name than through the scientific labors which added largely to the wealth of his native France. This philosopher proposed to calculate the amount of heat demanded by a plant, by multiplying the num ber of days required to pass through its growth by the mean temperature of the period. To Michael A.danson, a French naturalist, we are indebted for the hypothesis that, by adding together the mean temperatures of each day from the commencement of the year, it will be found that when the sum shall have reached a certain figure the same phenomena of vegetation will be exhibited, such as foliation, blooming, and maturation of the fruit. Boussingault revived the hypothesis of Reaumer and enlarged its application. Many years' residence in South America, engaged in scientific observation and research, where vegetation upon mountain sides appears under almost every aspect and condition, combined with experience in the pursuits of agriculture on his farm at Brechelbronn, in Alsace, had, taught him that if we multiply the number length of time a summer plant endures—by the mean temperature of this period, the product will be the same in all countries and in all years Baron Quetelet, of Brussels, experimented upon the amount of heat tequired by plants, and proposed that it should be measured not by the simple product of the temperature of the several days by the number of days required, but that the squares of the mean temneratures should be employed in lieu of the da ly mean. The younger De Candolle has, however, sought in vain in the researches of Quetelet and others for any positive facts show ing the direct advantages of the variations of heat over continuous even temperatures, or for the evidence fully determining that one day hav ing a mean of 20° centigrade, is of equal value with four days having each a mean of 10° centi grade, as is assumed by Quetelet. Babinet compared the action of temperature to that of a force, which produces effects proportioned to the intensity of the cause and the square of the time. He has not, however, made experience the basis of his hypothesis, and it is rejected by Quetelet as unsound. According to the latter philosopher, by the hypothesis of Babinet, if one day at 20° centigrade produces a certain effect, two days having a mean of 10° centigrade should produce four times 10° or the effect of 40° centigrade, and four days at 5° centigrade should exert an influence equal to sixteen times 5° or 80° centi grade—results which the general experience of horticulturists will not permit us to accept as true. Count Adrien de Gasparin, in his Course of Agriculture, suggests that the mean heat of the day should be derived in part from the direct heat of the sun, and not alone from that of the air, as is in general measured by meteorologists, because the motive power which induces the circulation of the sap is the heat derived from the atmosphere and the soil in conjunction with the direct rays of the sun. The rate of decom position of the carbonic acid absorbed from the air must be measured by the activity of the chemical rays of the sun, and the growth of the plant is accelerated, we are aware, by exposure to its full measure of sunshine. This method can not, however, be readily verified in the pres ent actual state of meteorological knowledge. This observer followed the -vegetation of one vari ety of vine growing near Orange, in France, from foliation to maturity, noted the minima of heat for each day in the shade, and the maxima shown by the thermometer in the sunshine, but protected by a slight covering of earth. The mean between these minima and maxima give, according to Gasparin, a more satisfactory number than that derived from other processes; and when multi plied by the number of days during which vegeta tion is influenced by this particular mean, results in a sum total of heat which varies but little from year to year at the locality where the observations were made. So nearly do these sums agree that the presumption is strengthened that the process may be the correct one, and deserving of much more attention than has been awarded to it. The result of de Gasparin's experiments in 1844 was a sum of 4195°; in 1845, 4203°; in 1846, 4057°, and in 1847, 4100° centigrade. The principle that we must combine the values of temperature and time in our inquiries into this subject can not be controverted, for all must perceive that heat acts proportionally as regards its duration and force. Boussingault, therefore, asserts that if a plant has required twenty days to ripen its seed, numbering from the period of flowering, and the mean tem perature during those twenty days has been 50°, it will be found that the plant will have received 1000° of heat. The same number of degrees of heat might have influenced the plant during a lesser number of days had the mean temperature been proportionally higher. This is well illustrated by the rapidity with which some annual plants ger minate in Arctic regipns on the return of midsum mer heats. In these northern regions, where for a short time plants are subjected to an intense heat, often as high as 109° Fahrenheit in the shade, and which enjoy a longer continuance of the sun above the horizon than in more southern latitudes, the growth of some vegetables is said to be so rapid under assiduous culture and in genial situa tions that their progress may be traced from hour to hour. In Norway, in latitude 70° north, peas grow at the rate of three and a half inches in twenty-four hours for many days iu'summer, and some of the cereals, probably barley and oats, grow as much as two and a half inches in the same time. Not only is the rapidity of growth affected by the constant presence of the sun's heat and light, but those vegetable secretions which owe their existence to the influence of the actinic force on the leaves are all produced in far greater abun dance than in more southern climes; hence the coloring matter is found in greater quantity. the tints of the colored parts of vegetables are deeper, the flavoring and odoriferous matters are more intense, though in saccharine properties the plants of Norway are not equal to those of the south. While there can be no doubt that different plants require different amounts of heat, from the time of sprouting to full maturity, though the time through which this may be furnished may be dif ferent in different instances, and that a great heat may produce the same effect on plants which is produced by a lower degree operating during a longer term, another principle of much ance must be observed in order to the successful cultivation of plants under natural or artificial cir cumstances. This second principle is that each species requires for each one of its physiological functions a certain minimum of temperature or, as has been well said, each species of vegetable is a kind of thermometer which has its own zero or lowest degree at which it will vegetate. A tem perature above a certain minimum of heat is found necessary for germination, another one for chemi cal modification, and a third for flowering, a fourth for the ripening of seeds, a fifth for the elaboration of the saccharine juices, and a sixth for the development of aroma or bouquet. A cer tain intensity of light is also demanded to render green the tissues, and a due supply of humidity in the air and in the soil to furnish a vehicle for the materials of growth and prevent undue desic cation. A plant is thus not only under all the influences which affect the thermometer, but is likewise acted upon as is a hygrometer by hu midity and dryness. Knowing as we do how much local influences, as supply of moisture, currents of air, elevation, Capacity of soil for absorbing and holding heat and moisture, and the various other conditions that may be seen by every observing person, alter the range of production in locali ties, we have the key to many of the difficul ties in the cultivation of crops, and thus may easily see why certain plants may be hardy and prolific in one locality and yet impossible to be successfully cultivated in another, not far distant. For instance the peach is at home in Western Michigan, near the lake shore, while in Illinois, not more than forty miles west, it can not be raised at all.. The climate of that State, modified by the unfathomable depths of Lake Michigan, is cooler in summer and warmer in winter and they escape spring frosts, prevalent in Illinois in the same latitude.