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of North America there is a continuous wooded region, extending from Hudson Bay to the Gulf of Mexico, while on the Pacific a similar arborescent growth embraces some of the most gigantic specimens of the vegetable kingdom. Within these bands of timber, which approach each other in their northern and southern reaches, are the great prairies extending transversely across the Mississippi Valley, and having their greatest expansion in the valley of the Missouri. Farther westward, from increasing dryness, the grasses entirely disappear, and the great American Desert usurps their place. This alternation of forest, prairie, and desert, corresponds with the precipitation of moisture. The ocean is the great source of moisture, and the clouds are the vehicles employed for its distribution over the land. From actual measurement it has been ascertained that they discharge most of their water on the exterior rim of the continents; that farther toward the interior the amount precipitated is less, and finally it is almost entirely supplanted by the aridity of the desert. In a section extending across the continent from New York to San Francisco, the amount of rain-fall strikingly coincides with the alternations of wood-land, prairie, and desert. The region extending from New York, which has an annual rain-fall of 42 inches, to Ann Arbor, having 29 inches, is heavily covered with timber; thence to Galesburg, Ill., having 26 inches,* is mostly prairie interspersed with clumps of forest; thence to Fort Laramie, having 20 inches, it rapidly changes to a continuous prairie ; thence to Fort Youma, having only 3 inches, it becomes an inhospitable desert; and thence to San Francisco, having 22 inches, it changes to luxuriant forests. Illinois is thus within the region of alternate wood and prairie, with the latter largely predominating. This wide belt, owing to a difference of capacity for retaining moisture, has its eastern and Western borders thrown into irregular outlines, resembling deeply indented bays and projecting headlands. As the result of decreasing moisture, only 90 arborescent species are found in the wooded region which on the east extends a considerable distance into Illinois, and all of these, except 6, disappear farther westward. The diminished precipitation in Illinois, and the great valley east of the Mississippi, while it has an unfavorable effect on the growth of trees, seems rather to enhance the growth of crops. In further confirmation of this theory, the same physicial laws which have diversified North America with forest, prairie, and desert, have produced similar effects upon other continents. Hence it is that Sonth America has its Atacama, Africa its great Sahara, Europe its barren steppes, and Asia its rainless waste of sand and salt, extending through more than 100 degrees of longitude. All these desert places, where local causes do not interfere, are girt about by grassy plains and belts of forest.
* The subjoined table has been kindly furnished us by Prof. Livingstone, of Lombard Uni. versity. It will be seen that the mean annual temperature of Galesburg is 48 degrees, and its mean annual precipitation of moisture 24 inches. The southern and western portions of the State slightly exceed the above figures:
Mar. Apr. May June July Aug. Sep.
26 14 24° 14'300 25' 490 28 609 | 29 700 32 590 40'71° 43' 630 33 500 25 390 11 26018480 26
Some eminent physicists refer the treeless character of the great grassy plains to the mechanical and chemical character of the soil. Perhaps, in the constantly varying physical conditions of different localities, the forces alluded to in these theories advanced, may all co-operate to produce these great grassy expanses, which constitute so large a part of the earth's surface. To Illinois they are inexhaustible sources of wealth, and as intimately connected with her destiny as the great coal fields which underlie them. Both are the expression of natural law, both destined to furnish the State with the elements of future greatness and power, and both prophetic of labor, intelligence and the enjoyment of a noble manhood.*
The Climatology of the State, in cominon with other countries of the same latitude, has four seasons. The melting snows of winter, generally attended by rains, convert the rich soil of the prairie intó mud, and render early spring the most unpleasant part of the year. The heat of summer, although more intense than in the same latitude on the Atlantic, is greatly relieved by the constant breezes which fan the prairies. Autumn, with slowly diminishing heats, terminates in the serene and beautiful season known as Indian summer. Its mild and uniform temperature, soft and hazy atmosphere, and forests beautifully tinted with the hues of dying foliage, all conspire to render it the pleasant part of the year. Next come the boreal blasts of winter, with its social firesides, and tinkling bells in the mystic light of the moon, as merry sleighs skim over the level snow-clad prairies. The winter has its sudden changes of temperature, causing colds and other diseases arising from extreme vicissitudes of weather. This is the most unfavorable feature of the climate, which in other respects is salubrious. The general belief that Illinois is scourged by bilious diseases is sub. stantially unfounded. It is well known that the pioneers of Ohio, Indiana and Michigan suffered far worse from inalarious diseases than those who first subdued the soil of Illinois. The cause of this is apparent. The malaria of marshes and unsubdued soils in wooded districts, excluded from the light of the sun and a free circulation of air, is far more malignant than that of the prairie having the full benefit of these counteracting agents.t
The most distinguishing feature of the climate is its sub-tropical summers and the arctic severities of its winters. The newly arrived English immigrant is at first inclined to complain of these climatic extremes, but a short residence in the country soon convinces him that many of the most kindly fruits and plants could not be cultivated and matured without them. Owing to this tropical element of the summer, the peach, grape, sweet potato, cotton, corn and other plants readily mature in Illinois, though its mean annual temperature is less than that of England, where their cultivation is impossible. These facts show that a high temperature for a short season is more beneficial to some of the most valued plants than a moderate temperature long continued. This is well exemplified in the cultivation of our great staple, maize, or Indian corn, which, wherever the conditions are favorable, yields a greater amount of nutriment, with a given amount of labor, than any
*See Geograpbical Surveys of the State, and Foster's Physical Geography of the Missis. sippi Valley
tFoster's Physical Geography.
known cereal. It was originally a tropical grass, and when cultivated in regions of a high and protracted temperature, exhibits a strong tendency to revert to its original condition. In the Gulf States it grows to a greater hight than farther northward, but its yield of seed is correspondingly less. In the valleys opening seaward along the Pacific slope, it attains a medium size, but fails to mature for the want of sufficient heat. Hence the districts of its maximum production must be far north of its native latitudes, and have the benefit of short but intense summer heats. In Illinois and adjacent parts of the great valley its greatest yield is about the 41st parallel, and though far less imposing in its appearance than on the Gulf, its productive capacity is said to be four-fold greater than either there or on the Pacific. It is wonderful that a plant should undergo such a great transformation in structure and natural habits, and that its greatest producing capacity should be near the northern limits of its possible cultivation. These facts suggest questions of great scientitic value relative to the development of other plants by removing them from their native localities.
One of the causes which assist in imparting these extremes to the climate may be thus explained. The different continental masses during the summer become rapidly heated under the influence of the sun, while the surrounding oceans are less sensitive to its effects. As the result, the lands bordering on the sea have a comparatively mild temperature, while the interior is subject to intense heat. During winter, for similar reasons, the interior becomes severely cold, while the sea-girt shore still enjoys a much milder temperature. But a greater modifying influence upon the climate are the winds to which it is subject. The source of these is at the equator, where the air, becoming rarified from the effects of heat, rises and flows in vast masses toward the poles. On reaching colder latitudes it descends to the earth, and as an undercurrent returns to the equator and supplies the tropical vacuum caused by its previous ascent. If the earth were at rest, the two under and two upper currents would move at right angles to the equator. But, owing to its daily revolution from west to east, the under-currents, as they pass from the poles toward the equator where the rotation is greatest, fall behind the earth, and that in the northern hemisphere flows from the northeast, and that in the southern from the southeast. In like manner the upper-currents, flowing from the greater velocity of the equator toward the less at the poles, get in advance of the earth; and the one in the north Hows from the southwest, and the other in the south from the northwest. If the globe were a perfectly smooth sphere, the flow of the winds as above described would be uniform, but the former being crested with mountain chains, the latter are broken into a great variety of local currents. In a belt of about 25 degrees on each side of the equator, the under-currents blow with the greatest regularity, and are called trade-winds, from their importance to navigation and commerce.
In making an application of these great primary currents to the valley of the Mississippi, and consequently to Illinois, it will be seen that the southwest winds, descending from their equatorial altitude, become the prevailing winds of the surface in our latitude. Besides these, the northeast trade-winds, in their progress toward the equator, impinge against the lofty chain of the Andes, and are deflected up the Mississippi Valley and mingle with the winds from the southwest. In their passage along the Andes Mountains, and across the Carribbean Sea and the Mexican Gulf, they become charged with tropical heat and moisture. On entering the great central valley of the continent, walled in on both sides by impassable mountain barriers, they are directed far northward, and, mingling with the southwest winds, dispense their waters, warmth and fertility, which are destined to make it the greatest theatre of human activities on the face of the globe. These winds, from local causes, frequently veer about to different points of the compass; and in Illinois and other prairies States, where there are no forest belts to break their force, frequently sweep over the country with the fury of tornadoes. Almost every year has recorded instances of the loss of life and property from this cause, and even in the great northern forests are tracks made by their passage, as well defined as the course of the reaper through a field of grain.
ILLINOIS ANTIQUITIES—THE MOUND BUILDERS.
It is the opinion of antiquarians that three distinct races of people lived in North America prior to its occupation by the present population. Of these the builders of the magnificent cities whose remains are found in a number of localities of Central America were the most civilized. Judging from the ruins of broken columus, fallen arches and the crumbling walls of temples, palaces and pyramids, which in some places for miles bestrew the ground, these cities must have been of great extent and very populous. The mind is almost startled at the remoteness of their antiquity, when we consider the vast sweep of time necessary to erect such colossal structures of solid masonry, and afterwards convert them into the present utter wreck. Comparing their complete desolation with the ruins of Balbec, Palmyra, Thebes and Memphis, they must have been old when the latter were being built. May not America then be called the old world instead of the new; and may it not have contained, when these Central American cities were erected, a civilization equal if not superior to that which contemporaneously existed on the banks of the Nile, and made Egypt the cradle of eastern arts and science?
The second race, as determined by the character of their civilization, were the mound builders, the remains of whose works constitute the most interesting class of antiquities found within the limits of the United States. Like the ruins of Central America, they antedate the most ancient records; tradition can furnish no account of them, and their character can only be partially gleaned from the internal evidences which they themselves afford. They consist of the remains of what was apparently villages, altars, temples, idols, cemeteries, monuments, camps, fortifications, pleasure grounds, etc. The farthest relic of this kind, discovered in a northeastern direction, was near Black river on the south side of Lake Ontario. Thence they extend in a south western direction by way of the Ohio, the Mississippi, Mexican Gulf, Texas, New Mexico and Youcatan, into South America. Commencing in Cataraugus county, New York, there was a chain of forts extending more than 50 miles southwesterly, not more than 4 or 5 miles apart, and evidently built by a people rude in the arts and few in numbers. Further southward they increase in number and magnitude. In West Virginia, near the junction of Grave creek and the Ohio, is one of the most august monuments of remote antiquity found in the whole country. According to measurement it has an altitude of 90 feet, a diameter at the base of 100 feet, and at the summit of 45 feet, while a partial examination discloses within it