Page:The American Cyclopædia (1879) Volume IV.djvu/695

 CLIMATE CLINGMAN 683 Fort Trumbull than at West Point, the former being upon the sea, and the latter inland. This difference is still more manifest in that portion of the North American continent lying north of the boundary line of the United States. In Nova Scotia, which is nearly surrounded by water, the thermometer seldom indicates a tem- perature higher than 88 in summer, nor more than 8 below zero in winter ; but in Canada, occupying the same parallels of latitude, the thermometer in summer rises as high as 97, and occasionally 100, while in winter a cold of 30 below zero is frequent, and the usual range of the temperature during the winter months is from 8 to 30 below zero. Eleva- tion above the level of the sea exercises a de- cided influence on climate. The temperature of the atmosphere is found to decrease in suc- cessive and regular gradation as it leaves the sea's level, so that in the ascent of lofty moun- tains within the tropics the traveller experi- ences every change of weather, from the op- pressive heat of the summer's sun on the plain below, to the piercing cold of eternal frost on the lofty summit above. The region of per- petual spring in the neighborhood of Potosi, in South America, is remembered with emotions of delight by every traveller who has ascended that ridge of the Andes. The declension of temperature has been found, with occasional variations, to equal 1 for every 300 ft. in tem- perate climates. This subsidence of tempera- ture with elevation is doubtless dependent on the extreme rarity of the atmosphere at a dis- tance from the earth, and the consequent fa- cility with which it is permeated by heat, as well as the radiating power possessed by the earth, which enables it to return to the con- tiguous atmosphere a portion of the solar rays it had previously absorbed. The atmosphere is condensed in proportion to the force with which it is compressed, and expands in exact ratio to the diminution of that force. It fol- lows that, the superincumbent strata of air being compressed with greater force in its most dependent part, and that dependent part being nearest the earth's surface, its density will be there greatest, and this density will diminish in exact proportion to the ascent of the column of air. Now the atmosphere when under a certain compression has a cer- tain capacity for latent heat, which is in- creased by a diminution of the compression, and diminished by its increase. If a column of air at a certain distance from the earth re- ceive a certain number of the sun's rays, and then be brought suddenly down to occupy a denser medium, its particles becoming com- pressed, a portion of the latent heat becomes sensible and is given off to surrounding bodies. The following observations, made by Mr. Green during an aerial voyage, exhibit this declension of temperature. The thermometer at the earth's surface indicated a temperature of 74 ; at an elevation of 2,952 ft., 72 ; at 7,288 ft, 70 ; at 9,993 ft, 69; at 11,059 ft, 45 ; at 11,293 ft., 38 ; making a difference of 36 between the earth's surface and the highest altitude at- tained, or about 1 for every 311 ft Sir John Leslie and Humboldt believe that the diminu- tion is much more marked near the surface of the earth than is here indicated. Mr. Glaisher, in his midday ascents, found an average fall in temperature of 1 in 223 ft. for the first 1,000 ft. with a cloudy sky, and in 162 ft. with a clear one ; while above 10,000 ft. the decline was 1 in 455 and 417 ft. respectively, and above 20,000 ft. it was only 1 in nearly 1,000 ft. under both conditions. (See AERONAUTICS.) But this reduction does not apply to elevation of large areas of surface above the level of the sea. It is only applicable to actual distances from the surface, or elevations- in the atmos- phere itself from any general surface. Moisture exercises very marked influence over climate. Taken as a whole, all the gentle slopes on the American continent descend eastwardly toward the Atlantic, while the abrupt ones rise on its western aspect. In this respect there is a man- ifest difference between this continent and that of Europe, which gradually declines westwardly toward the Atlantic. This general configuration necessarily gives to Europe a moister as well as a more temperate climate than that of America in the same parallels of latitude. This would be much more obvious were it not for the admir- able compensation made by the Gulf stream and the trade wind that accompanies it. From this source not only the Atlantic coast, but the Mississippi valley, which is exposed on the south to the gulf of Mexico, derives a large proportion of its moisture. (See METEOROLOGY.) CLIMBING PERCH. See ANABAS SOANDENS. CLINCH, a S. E. county of Georgia, bordering on Florida, bounded S. W. by the Suwanoo- chee river, which also intersects it, and W. by the Allapaha, and intersected by the Little Suwannee ; area, 1,000 sq. m. ; pop. in 1870, 3,945, of whom 507 were colored. The surface is level and swampy. The Atlantic and Gulf railroad passes through the county. The chief productions in 1870 were 41,605 bushels of Indian corn, 21,054 of oats, 22,589 of sweet potatoes, 330 bales of cotton, 153,325 Ibs. of rice, and 1,060 of honey. There were 263 horses, 3,201 milch cows, 6,216 other cattle, and 7,753 swine. Capital, Magnolia. CLINCH RIVER rises among the hills of S. W. Virginia, passes into Tennessee, flows through the valley between Clinch and Powell moun- tains, and unites with the Holston at Kingston, to form the Tennessee. Its length is estimated at about 200 m., for more than half of which it is navigable by small boats. CLINGMAN, Thomas L., an American politician, born at Huntsville, N. C., about 1812. He graduated at Chapel Hill university in 1832 ; became shortly after a member of the state legislature, and in 1843 was elected to congress, remaining a member of the house of repre- sentatives, with the exception of a single term, till 1858, and becoming chairman of the com-