NATIONAL BOUC. ASSOC.                     I306                                          NATURAL GAS

in 1909, according to the Bureau of Statistics of the Department of Commerce and Labor, U. S. A., was: Great Britain (funded and unfunded debt), $3,839,620,745; France, total debt, including interest and annuities, $5,898,675,451; Germany, total debt (bearing interest at 3% and 3$%), less war treasury fund, about $1,094,790,975; Russia, total debt, including that incurred for state railroads, $4,558,152,565; Italy, $2,602,-299,757! Austria-Hungary, consolidated and floating debt, $1,063,725,105; China, outstanding foreign debt (raised chiefly to meet expenses connected with the war with Japan), $601,916,605; Japan, $1,287,604,261; Mexico, $219,899,231; and Canada $323,930,279.

Na'tional Educational Association. This important body was organized as the outcome of a convention of teachers in Philadelphia in August, 1857. It declared its object to be "to elevate the character and advance the interests of the profession of teaching and to promote the cause of popular education in the U. S." The association holds yearly national conventions at different centers. In 1866 women were admitted to full membership. In 1870, when the title was changed from National Association to National Educational Association, began the policy of organizing different departments for the purpose of giving special attention to problems which chiefly interest given classes of teachers. In this way were organized the department of normal schools, the department of school-superintendents, both of which had previously existed as independent societies meeting by consent with the association, with the new department' of elementary education and of higher education. The N. E. A. has held regular annual meetings except in 1861, 1862, 1867, 1878, 1893 and 1906. Its proceedings form a valuable storehouse of expert opinion and scientific research upon miscellaneous educational topics and problems. For many years, nevertheless, the membership was low; but in 1884 the enrollment reached 2,729. A permanent fund was inaugurated, which in 1906 amounted to $155,000. In 1886 the Association was incorporated for 20 years at Washington, D. C, and in February, 1906, it was re-incorporated by Act of Congress. The N. E. A. may be regarded as an organized attempt at social participation in the task of distributing to each the accumulated experience of all. In 1895 a permanent active membership was created; and in 1898 provision was made for a permanent and salaried secretary, to give his whole time to the Association. In its jubilee year (1907), which the N. E. A. celebrated at Los Angeles, Cal., the important step was taken of the separate publication of an index supplement to the Proceedings from 1857 to 1906.

National Forests. See Forest-Reserves and Forest-Service.

National Parks. Forest-reserves and national parks are often confused, but they are not the same things. Forest-reserves (a. v.) are areas for the protection of natural resources by the national administration. National parks are large tracts of public lands reserved from settlement or residence and also retained, maintained and improved by the federal government. As the government has laid out some of our great tracts of forest, as well as stretches of land of unusual beauty, as national parks, it follows that some of the forest-reserves are parks, though not all of the parks are forests. The present national parks were created during 1872-1904, and have an area of 5,276,272 acres or more, and play no small part in the improvement and development of all other parks throughout the United States. Among the more important national parks, ranking them according to their extent, are the Yellowstone (q. v.) in Montana and Wyoming; Tacoma (or Rainier) in Washington; Yosemite (q. v.), Sequoia and Grant in California; Hot Springs (q. v) in Arkansas; Crater Lake in Oregon; and Casa Grande in Arizona. Yellowstone Park, including the Teton and Yellowstone timber-reservations, covers 5,575 square miles (or 2,142,720 acres in the park proper), three fourths of the area of Massachusetts; Rainier 2,000,000 acres; Yosemite 1,512 square miles; Sequoia, where only Mariposa Grove is efficiently protected, 250 square miles; Grant four square miles; Hot Springs 912 acres; and Casa Grande 480 acres. Consult government reports and Muir's Our National Parks.

Nat'ural Bridge, The, an arch of limestone which spans a small river in Virginia, one of the features of the landscape in the far-famed Shenandoah valley. It stands among cascades, caverns and deep pine-woods, a mighty arch of a single stone. It is 215 J feet in height and 100 wide, and has a span of 80 feet. It is west of the Blue Ridge, and 14 miles from Lexington, Virginia.

Natural Gas, combustible gas which escapes from beneath the soil in such quantities' that it may be used for fuel or illuminating purposes. In its natural state the gas occurs in porous sedimentary rocks, and, when proper openings are made, it rises to the surface. Wells are drilled for gas, as for oil or water. Natural gas is the product of decay or distillation of organic matter buried in sand, mud etc. By its burial the organic matter is shut off from contact with the air, and hence the gases arising from its deposition and distillation are not completely oxidized. Organic matter is now being imbedded in sands and muds which are in process of deposition on lake and sea bottoms. Under proper conditions this might ultimately give rise to gas. Natural gas is really a mixture of several gases in