Page:Encyclopædia Britannica, Ninth Edition, v. 17.djvu/321

NEBRASKA 307 their curious crater-like forms. They extend to the head of the forks of the Loup river, covering an estimated area of 8000 square miles. Climate. The average mean temperature of the summer months June, July, and August in eastern Nebraska is 73 Fahr. At the North Platte it is slightly higher. Excepting a small section in the north-western part, the whole State is included between the summer isotherms of 72 and 76. The mean temperature of the autumn months September, October, and November is 49. As excessive rains rarely fall during these months, the comparatively high mean temperature renders the autumn season long and delight fully mild. The isotherm of 20 during the winter months December, January, and February embraces all of Nebraska except the north-west corner, where the temperature is slightly lower, and the south-east corner, where it is slightly higher. The spring months March, April, and May have a mean of 47 Fahr. The mean of the whole year is in the southern half of the State 55, in the northern half 52|-. Rarely does the tempera ture in midsummer rise to 100. In twelve years the thermometer fell below zero on an average thirteen times a year. The lowest point ever reached was 32 below zero. The heat of summer is constantly modified by breezes. Owing to the dryness of the atmosphere the cold is not felt more when the thermometer registers - 20 than in moist regions when it marks only zero. In winter the prevailing winds are from the north-west, changing, as spring advances, to the south-west, from which direction they mainly blow through summer and autumn. During some winters there are occasional wind-storms of great severity, preceded by a fall of snow, and followed by very low temperature. Such storms last from one to three days, and when they cease the temperature reaches the lowest point experienced in this region. The extreme cold continues for a few days only. Fortunately the severe types of such storms are rare even here, and the winters on the whole are remarkably adapted to continuous labour in the open air. The atmosphere is wonderfully clear and pure throughout the -year ; objects can be seen at a great distance, and clouds when formed are outlined with exceptional clearness. The rainfall in eastern Nebraska is abundant. At the Missouri it averages 40 inches a year; 100 miles farther west 32 inches ; 200 miles west of the eastern boundary 30 inches. Beyond this point it more rapidly lessens until the North Platte is reached in western Nebraska, where the average is only 20 inches. In the end of May, or in early June, when the " big rise " of the Missouri and the Platte occurs, a rainy season invariably commences which lasts from three to eight weeks. As this is the time when crops most need rain, destructive droughts are rare in eastern Nebraska. After the wet season rains still occur, but at longer intervals. During winter rain rarely falls. Snow ranges in depth from 1 to 10 inches. There are many facts that show a constantly increasing rain fall in the State. One reason for this is believed to be the great depth of the soil, and the great increase of absorption produced by cultivation. The loess soils, of which the surface of Nebraska is largely composed, only need the native sod to be broken up to be transmuted into a huge sponge absorbing all the moisture that falls on it. Nebraska is exceptionally healthy, especially for persons of consumptive tendency. This is owing to its elevation above the sea, the dryness of the atmosphere, and the great amount of ozone in it, the prevalence of winds, and the fine natural drainage of the State. The diseases incident to the climate are rheumatism, neuralgia, and in isolated spots malaria. With the progress of settlement, and a lessen ing exposure, these ailments are gradually disappearing. In striking contrast to past geological times, there are Lakes, now no large lakes in Nebraska. There are, however, a great number of small lakelets. Many of these have been formed by "cut offs" on the Missouri, Platte, Elkhorn, Blue, and other rivers. At the head of the Elkhorn river is a region containing over thirty small lakes, many of which are of great beauty, with pebbly bottoms, and water clear as crystal. A still more extensive region of small lakes is at and between the heads of the Loup rivers. At the head of Pine Creek, a tributary of the Niobrara, there are many saline lakelets and ponds. A large saline bog, fed by a vast number of saline springs, covers about 500 acres, 2 miles west of Lincoln. Many smaller ones exist in the same vicinity. Salt has been manufactured here in con siderable quantity by solar evaporation. Springs are Springs. abundant along most of the river bluffs and on the rolling lands of eastern Nebraska. On the long reaches of nearly level land springs occur at longer intervals, and on the watersheds still more rarely. Even here water can readily be obtained by wells, from 15 to 50 feet deep, excepting in a few counties like Clay, Fillmore, Adams, and Phelps, where, owing to the great thickness of the superficial deposits in some localities, shafting must be much deeper. Artesian wells have been successful, the depth at which flowing water has been obtained varying from 500 to 1000 feet. 1 The name Nebraska signifies land of broad rivers. Rivers. Chief of all is the Missouri, which flows in a tortuous course for 500 miles along its eastern boundary, and is navigable for 2000 miles above Omaha. Next in import ance is the Platte, which flows through the whole length of the State from west to east. Rising in lakelets in the Rocky Mountains, fed by snows, its entire length approxi mates 1200 miles. When it enters the State it is already a broad and rapid, though shallow, river, flowing over a sandy bed. At North Platte it forks, one branch being known as the South and the other as the North Platte. The Loup is the first large tributary. It rises among the sand-hills south of the Niobrara, in a group of small lakes. It has three main branches, known as the South, Middle, and North Loups, each of which in turn has many tribu taries. The Middle Loup, whose main direction is south east, is 250 miles long. The Elkhorn, which empties into the Platte a short distance above the latter s junction with the Missouri, is one of the most beautiful streams of the State. It too has its source in a region of small lakes near 99 30 W. long. Here it has a remarkably broad bottom, with low bordering uplands. It flows over a rocky bottom in a south-easterly direction about 250 miles. Its principal tributaries are the North Fork and the Logan, the latter having an extraordinary number of tributaries. Near the south line of the State the Republican river and its numerous affluents drain a large area. It rises in the Colorado plains, but flows 216 miles through the State. Near the northern boundary is the Niobrara river, which rises in Wyoming, and flows 263 miles through the State before uniting with the Missouri. It is the most rapid and turbulent stream in the State. In 102 30 W. long., where it is 80 yards wide, it enters a deep canon with high and often perpendicular walls, which extend for 180 miles. After emerging from the canon it remains a broad, rapid, and sandy river to its mouth. The most important of its numerous tributaries are the Keya Paha and the Verdigris. Many other rivers in Nebraska are remarkable for the beauty and fertility of the sections which they drain, the most important being the Bows, the Big and Little 1 An artesian well in the Government Square in Lincoln struck brine at 250 feet, and at 550 feet a heavy flow was encountered. The source of the brine was the reddish sandstone of the Dakota group (Cretaceous), which here underlies the superficial deposits.