industry. The neighboring Saint Léon mineral springs are much frequented as a health resort. Population, in 1891, 1740; in 1901, 1655.
LOUISIADE (lo͞o-ē′zē̇-äd′) ARCHIPELAGO. A group of islands in Oceanica, situated at the southeastern extremity of British New Guinea, to which it belongs (Map: Australasia, H 4). It consists of three large islands—Saint Aignan, Southeast Island, and Rossel, each with an area of from 100 to 300 square miles—and numerous small islets and reefs. The large islands are mountainous, having peaks which rise to a height of over 3000 feet, while the islets are chiefly of coral formation. The group is inhabited by savages of Papuan race. The islands were discovered by Torres in 1606, and taken by the British in 1888.
LOUISIANA, lo͞o-ē′zē̇-ä′nȧ or -ăn′ȧ (named as a colony in honor of Louis XIV. of France). One of the Gulf States of the American Union. It is on the lower course of the Mississippi River, and includes the great delta within its limits. It lies between the parallels of 29° and 33° N. latitude; it extends on the east to longitude 89° W. and its westernmost part lies just beyond longitude 94° W. It is bounded on the north by the State of Arkansas. Its eastern boundary is mainly Mississippi, following the Mississippi River to latitude 31° N., running east on this parallel to Pearl River, which it follows to its mouth in Lake Borgne; farther south it has the Gulf of Mexico on the east. The Gulf washes its entire southern margin, and Texas bounds it on the west. The western boundary follows Sabine Lake and River to latitude 32° N., thence it extends due north to latitude 33°. The State has an area of 48,720 square miles, of which 3300 square miles is water. Of the water area 1700 square miles is made up of inland lakes, 1060 square miles of land-locked bays, often called lakes, and 540 square miles of river surface.
Topography. The highest ridges, in Claiborne and Union parishes, rise to 500 feet above the sea. The land slopes almost imperceptibly to the southeast. The bottom lands of the Mississippi River at the Arkansas line have an elevation of 130 feet, at Natchez 66 feet, at Baton Rouge 34 feet, at New Orleans 15 feet. The average elevation of the State is only about 75 feet above sea level. All the rivers have flood plains of generous width, more or less liable to inundation at times of high water. These bottom lands, in the case of the Red and Ouachita (Washita) rivers, average 10 miles in width; on the Mississippi River, from 10 to 60 miles. Through these flood plains the rivers meander on a decreasing gradient, constantly depositing their loads of silt. This results in building up their beds, until the river flows at the summit of a ridge. From the river edge the land slopes away with a gentle gradient of about seven feet in the first mile, then with only six inches per mile to the marshes and bayous of the outer margin of the flood plains. These river margins furnish a soil of inexhaustible fertility and are largely utilized for plantations of cotton and sugar cane. They are protected from overflow by artificial banks or levees of varying height, there being over 1500 miles of such levees in Louisiana. Occasionally at times of great flood the levees give way in places, the ‘crevasse’ allowing the river to overflow the adjacent bottoms and carrying destruction far and wide. The Gulf margin extending about sixty miles inland consists of a marshy plain, the only land being the raised river margins and occasional small patches of prairie and live-oak ridges, the prairie area increasing to the west. This lowland and the river bottoms cover an area of 19,200 square miles, or a little less than one-half the area of the State.
The principal rivers are the Mississippi, which flows 600 miles through the State and along its bprders, the Red, Ouachita, Sabine, and Pearl; and all of these are navigable at all stages of water. Most of the large rivers of the lowland region are distributaries of the Mississippi and Red rivers, locally called bayous, and nearly all are navigable. They interlace all over the area in the most bewildering fashion. The most important ones are Atchafalaya Bayou, Bayou la Fourche, and Bayou Bœuf. These bayous are very active in taking off the excess water in time of flood.
The lakes are of three classes: First, those of the coastal margin—Pontchartrain, Borgne, Maurepas, Sabine, and many others; they are merely parts of the submerged coastal plain which have escaped filling by delta action. They have salt or brackish water and their level rises and falls with the tide. Second, a host of crescent lakes, oxbow lakes as they are called, which are the unfilled portion of amputated and abandoned meanders. They are usually connected with the river at the lower end by a bayou. The third class of lakes is found in the tributaries of the Red River in the vicinity of Shreveport, and are due to the more rapid silting up of the channel of the master stream than of its tributaries, thus drowning the lower courses of the lateral streams. The main body of the delta proper of the great river extends about seventy miles beyond the general trend of the Gulf coast, while the remoter passes advance about 35 miles still farther into the Gulf.
The great delta is rapidly advancing into the Gulf, depositing in excess of the waste of the waves and of a possible sinking of the immediate region, and it gives promise of annexing the Mobile system in the immediate geologic future. The rapid silting in the passes leaves a maximum depth at the outer bar of only twelve feet, though the main river has a depth of 100 feet from the mouth of the Red River down to the passes. Capt. J. B. Eads was appointed by the Government in 1875 to construct artificial banks or jetties in the passes, narrowing the stream and compelling it to corrade a deep channel and to keep it open. It was a complete success, a thirty-foot channel having been maintained ever since, so admitting vessels of the largest class to the port of New Orleans.
Climate. The State enjoys a semi-tropical climate, and the proximity to the Gulf makes its climate remarkably equable. The cyclonic storms of temperate latitudes travel for the most part to the west and north, making the prevailing winds south and southwest, so carrying the tempering influence of the Gulf over the State for the most of the year. Occasional anti-cyclonic areas, however, bring north and northwest winds, varying the humidity and temperature widely. The average temperature for January is 60° F. in the delta and 45° at Shreveport. The absolute minimum temperature brings zero F. to the northwest corner of
