Monongahela. The last two join to form the Ohio.
Climate. The climate of the Appalachian Mountains must be characterized as temperate, as they extend from a region in which the average annual temperature is 46° F. southward to a region of 61° F. The region, therefore, partakes of the general climatic conditions of its latitude, modified by its altitude. As the prevailing winds come from the southwest, they do not bring much moisture, and the rainfall and snowfall are not excessive, though greater upon the heights of the central ranges than in the lower areas outside. The rainfall for the year averages about 40 inches throughout most of the Appalachian region, but in the southern section increases to 60 or 70 inches. Droughts frequently occur at the north, but seldom at the south. On the whole, the summer climate of the Appalachian region is delightful, and its charms are becoming more and more appreciated by summer visitors. This attractiveness is increased by the abundance of vegetation, the beautiful scenery, in which grandeur may often be found, and particularly by the presence in many parts of the mountains of springs of saline, chalybeate, and other mineral-bearing waters, both hot and cold. These medicinal waters, together with the purity and energizing character of the air, has long given the mountains, especially in North Carolina and Virginia, a high repute as a health resort.
Vegetation and Fauna. The Appalachian region is covered with a dense forest growth where it has not been removed by man, forest trees covering the mountain slopes practically to their summits, except where the barren rocks furnish no soil. The chief trees in the north are the sugar maple, white birch, beech, ash, pine, and hemlock: in the south, oaks of various kinds, chestnut, hickory, poplar, tulip, ash, beech, maple, linden, red birch, cherry, with a sprinkling of a dozen other varieties. Especially at the south extensive thickets of laurel and rhododendron border the water-courses. Ferns, wild flowers, wild grasses, and the wild pea vine furnish an abundant herbage. In the northern section most of the valuable timber has been removed and vast areas desolated to secure tree bark for tanning purposes. At the South, however, the forests retain much of their primeval character and magnificence, some of the trees being of gigantic size. Of the larger mammalia bears, deer, wildcats, are still common, but by no means plentiful. Wolves and panthers have practically disappeared. Small game birds and, at the South, wild turkeys are plentiful. Unfortunately, rattlesnakes and copperheads are to be found all over the mountains, yet rarely in dangerous numbers. The woods and streams abound, beyond almost any other part of the Temperate Zone, in fresh-water mollusks.
Mineral Resources. Economic products of considerable importance are found in the Appalachian region. Coal (q.v.) is far the most important; the entire anthracite field and part of the bituminous field of Pennsylvania and other States lie in the Alleghany Mountains and the Cumberland plateau or its northern extension. The petroleum and oil fields of New York, western Pennsylvania, and southward, barely touch the edge of the Appalachian region. Of the metals, iron occurs as hematite, limonite, and magnetite at many localities; zinc is found in association with magnetite at the well-known localities of Franklin Furnace and Ogdensburg, N. J., and as blende, calamine, etc., associated with lead, at the Bertha Mines in Wythe County, Va. Lead has been found in small amounts at many points, but does not occur in sufficient quantity to constitute an independent industry. Copper is found native in the crystalline rocks of Virginia, and as chaleopyrite often in large masses, as at Ducktown, eastern Tennessee. Gold and silver occur in small amounts chiefly in Georgia and North Carolina; nickel and cobalt are also found sparingly. Bauxite, one of the ores of aluminum, has assmned great importance in Alabama, and manganese has been mined in large quantities in Tennessee and Virginia. Natural cement, of such high grade as to make it a rival of Portland cement, is found at many outcrops of the Upper Silurian formations in New York, New Jersey, Pennsylvania, and Maryland, and lime is burned throughout the region. Building stone of good quality is abundant, and slate of excellent grade is quarried in New Jersey and Pennsylvania. Asbestos, mica, garnet, and emery are mined in Virginia, the Carolinas, and Georgia, and gems of many kinds are found in the Blue Ridge.
Bibliography. A. Guyot, “The Appalachian Mountain System,” American Journal of Science, second series, Volume XXXI. (New Haven, 1861); C. W. Hayes, “The Mechanics of Appalachian Mountain Structure,” Annual Report United States Geological Survey, Volume XIII., Part II. (Washington, 1892); B. Willis, “The Northern Appalachians,” National Geographic Monographs, Volume I. (New York, 1895); C. W. Hayes, “The Southern Appalachians,” National Geographic Monographs, Volume I. (New York, 1895); C. W. Hayes and M. R. Campbell, “Geomorphology of the Southern Appalachians,” National Geographic Magazine, Volume VI. (Washington, 1894); C. W. Hayes, “Physiography of the Chattanooga District in Tennessee, Georgia, and Alabama,” Annual Report United States Geological Survey, Volume XIX., Part II. (Washington, 1899); B. Willis, “Paleozoic Appalachia, or a History of Maryland During Paleozoic Time,” Maryland Geological Survey, Special Publication, Volume VI., Part I. (Baltimore, Md., 1900); Chapman, Flora of the Southern States (New York, 1883); Lounsberry, Southern Wildflowers and Trees (New York, 1901).
See Mountain; Anticline; Physiography; Geology; United States.
AP'PARA'TUS ( Lat., from ad, to + parare,
to make ready, prepare). In the sciences, a
collection of tools or instruments for experiment-
ing or working. In i)hysiolog^-, a group or col-
lection of organs associated in a single function ;
as, the heart, veins, and arteries are the circu-
lator- apparatus ; the legs are the apparatus of
locomotion, etc.
APPARATUS, Psychological. See Psychological Apparatus.
APPAR'ENT (Lat. ad, to + parere, to come
forth, lie visible) . A term used to express a num-
ber of important distinctions, especially in as-
tronomy. The apparent diameter of a heavenly
body is the angle formed by two lines drawn
from its opposite ends to the spectator's eye ; this
obviously depends upon the distance of the body,
