NATURE STUDY

Greece.

NAVAJOS

Na'ture Stud'y, branch or department of the American educational system; recently introduced as a part of regular school work, and received with general favor. Its object is to interest the child in the world about him, by making him more familiar with the things he oftenest meets. Moving things, as birds, insects, and animals, interest children most, and are therefore most proper for nature study, but they are also the most difficult to obtain. The most practical materials for the purpose are plants. Where a teacher can take a class of children into a patch of woods and explain the various growths there seen, the time spent will be a physical and mental advantage of much value. Where this and other short sightseeing trips are not practicable, the prime object of nature study may be pleasantly promoted by an exposition and explanation of suitable objects in the classroom. Cornell Univ. was the first notable institution to organize a system for nature study in the schools, and has done much by publishing hints and aids to promote the work.

Naucratis, or Naukratis (na'kră-tis), garrison city established by Psammetichus I, abt. 665 B.C., for his Ionian and Carian mercenaries; was located at what is now called Tell Nebireh, on a canal W. of the Rosetta branch of the Nile, near Sais, the capital of the twenty-sixth dynasty, and close to the Libyan frontier. Its site was discovered by W. M. Flinders Petrie, 1883, and explored by him, 1885-86. Its origin was entirely Greek. Naucratis contained a number of large buildings-a temple to Hera, another to Aphrodite, a small one to the Dioscuri, the Panhellenion, the largest of all and the Greek religious center of Egypt, and, oldest of all, a temple to the Milesian Apollo, in the center of the town. The discovery of Naucratis was important in its results, since it threw light on the earliest intercourse between Egypt and Greece, and also on the history of the Greek alphabet, the Naucratian specimens of Greek caligraphy being among the oldest known.

Naumburg (nowm'bõrkh), fortified town of Prussian Saxony; on the Saale, 23 m. SSW. of Halle. The restoration of the cathedral, one of the finest specimens of German medieval architecture, was begun, 1874. An annual children's festival is celebrated here, in commemoration of the raising of the siege by the Hussites under Procopius, said to have taken place, July 28, 1432, in consequence of the entreaties of the children of Naumburg. It has active manufactures and commerce. Pop. (1900) 23,187.

Nauplia (na'pli-), town of Greece; on the Gulf of Argolis; 58 m. SW. of Athens. Its three forts make it the strongest maritime town of Greece. In 1824-34 it was the seat of the government. In antiquity it was the

Nausea (na'she-a), sensation at the pit of the stomach which usually precedes vomiting. It may be produced by certain drugs, the continued rotation or swinging of the body, the unaccustomed motion of a vessel on the waves, improper food, a blow on the head, and in sensitive persons offensive odors, sudden alternations of temperature, and even moral impressions. If the sensation be excited by any substance which has been taken into the stomach, the best treatment is to favor the act of vomiting by copious draughts of warm water. If it depends on any other of the causes named, quiet, a horizontal position, and freedom from all sources of disturbance are most

effectual.

See VOMITING.

the interior is divided by partitions into numerous chambers, which are connected with one another by a tubular structure, the siphuncle. The animal occupies the large outer chamber. The only existing genus is Nautilus, and of the habits of this almost nothing is known, for while the shells-familiar as the "pearly nautilus"-are common, the animals are among the greatest rarities. These animals feed on small crabs. Fossil forms belonging to this family are numerous, over 2,000 species being described; only six living species are known.

Navajos (nä'vä-hoz), members of a tribe of N. American Indians, belonging to the Apache

NAVAL ACADEMY

family and the Athabascan stock, occupying a large reservation in Arizona; formerly almost constantly at war with the Mexicans, and, till 1863, with American whites; now well advanced in civilization and largely engaged in agriculture and raising live stock; numbered (1900) abt. 20,000.

Na'val Acad'emy, U. S. See UNITED STATES NAVAL ACADEMY.

Naval Observatory of the Unit'ed States, an institution under the Navy Department of the U. S. located at Georgetown, D. C. It was established in 1842 as the depot for naval charts and instruments. The "Nautical Almanac " is here compiled. The elaborate equipment of the observatory includes a 26-in. equatorial telescope which, when installed in 1874, was the largest of its kind in the world.

Naval Sig'nals. See SIGNALING; SIGNAL SERVICE.

Navarino (nä-vä-rē'nō), fortified town of the Morea, Greece, at the S. extremity of a bay of the same name, 3 m. from Old Navarino. The bay, about 3 m. long and 2 m. wide, is shut in by the island of Sphacteria, or Sphagia, where the Athenian Cleon defeated the Spartans, 425 B.C. Here, on October 20, 1827, the combined British, French, and Russian fleets destroyed the Turkish-Egyptian fleet. Pop. abt. 2,000.

Navarre (nă-vär'), province of Spain, between the Pyrenees and the Ebro; area, 4,055 sq. m.; pop. (1900) 307,669; capital, Pamplona. The old kingdom of Navarre (which originally included also what is now the French depart ment of Basses-Pyrénées) successfully resisted the invasions of the Saracens, and remained independent until Ferdinand and Isabella conquered it, 1512, and annexed it to Aragon; it preserved many peculiar privileges, however, which were not finally abolished until 1876.

Nave (nav), in architecture, a term used to designate in general the principal hall of a church as distinguished from the choir, transepts, chapels, or side aisles. It is also sometimes applied in secular architecture to large and imposing halls of more than usual length and loftiness, which resemble in form and proportion the nave of a church. The typical arrangement of the nave and side aisles in Christian architecture was derived from the Roman secular basilicas. These were halls with nave,

side aisles, a species of transept, and an apse or tribune. The naves, separated from the aisles by arcades or colonnades, were lighted by clerestory windows and covered with wooden roofs, sometimes with open trusses, sometimes with richly paneled or coffered ceilings. In

a cruciform church the nave extends from

the front to the transepts, and is commonly flanked by single or double side aisles on either hand.

Naviga'tion, art of conducting a ship from port to port and across the ocean with safety and dispatch, and, more particularly, of deter

NAVIGATION

mining her geographical position from time to time by observations of the heavenly bodies. Before going to sea, the ship should be furnished with charts of the ocean to be traversed; a sextant or octant; a compass fitted with attachments for observing azimuths; a nautical almanac for the current year; a chronometer running on mean time whose error for a given meridian (generally that of Greenwich, England) and daily rate of error are known; a standard work on practical navigation; a lead line marked for taking surroundings; and a log line for measuring the ship's speed. When the cargo is stowed and the vessel otherwise ready for sea the local deviation of her compass should be determined. As the ship stands out to sea a departure is taken; i.e., the ship's latitude and longitude are found from the chart by the bearing and distance of one landmark, or from the bearing of two or more marks whose positions are laid down on it. As soon as this departure is taken the course is shaped for the port to which the ship is bound, due regard being had for the winds, currents, and dangers to navigation to be encountered by the way, and from this time on the courses steered, the speed of the ship, etc., are duly noted in the log book.

Suppose the ship sails at night. At or about 8 A.M., or, better still, when the sun bears most nearly true E., and yet has risen high enough to avoid the irregular refraction near the horizon, its altitude (angular distance above the sea horizon) is measured with the sextant, and the instant of observation is noted by the chronometer. With the latitude and longitude of the ship at the time of taking the departure, with the courses and distances sailed, the former corrected for variation, leeway, and deviation to the time of the observation, the latitude and longitude, or position by dead reckoning, is computed by trigonometry. From the altitude of the sun observed (corrected, as all altitudes of the sun taken at sea have to be, for semidiameter, par

allax, dip, refraction, and the index error of the

sextant), we have the true altitude of the sun's center as seen from the center of the earth; from The Nautical Almanac the sun's declination for the instant of the observation is

obtained; and by the dead reckoning the approximate latitude. These data give the three sides of the astronomical triangle; and from this is computed one of its angles, the hour angle of the sun, the local apparent time, which is converted into mean time by the application of the equation of time taken

from the almanac; the difference between the local mean and the chronometer time gives the

longitude by observation.

Near noon the observer again begins to observe the sun, and continues to do so as long as the altitude increases, noting the sextant reading at the greatest altitude attained. The sun is said to dip when the altitude begins to decrease. The greatest altitude is assumed to be that when on the meridian, which is correct within small limits. By combining the sun's meridian altitude with its declination, the declination of the zenith, which is the

NAVIGATION LAWS

The

latitude of the position, is obtained. ship's run worked from the place of departure gives the latitude and longitude by dead reckoning; from the longitude by the A.M. observation corrected for the ship's run to noon the longitude by observation, and from the meridian altitude the latitude by observation is obtained. Any difference between the ship's position by observation and dead reckoning is ascribed to current, and its set and amount are, respectively, the bearing and distance of the position by observation from that by dead reckoning.

The sun, however, may be obscured by clouds at the time of its crossing and meridian, and then it is necessary to use some other method than the one given for finding the latitude. Appropriate formulas have been deduced for this by considering in the astronomical triangle the coaltitude and codeclination (the respective differences between a right angle and the altitude and declination angles), and the hour angle. This last, at sea, is always somewhat in doubt, but small errors in the hour angle, when the angle itself is small, produce but slight errors in the latitude; under most circumstances good latitude results can be obtained from observations taken within one hour of the sun's transit over the meridian. Observations of other heavenly bodies may be used for determining the latitude, longitude, and error of the compass. They are less resorted to, however, because of the difficulty of seeing clearly the horizon at night, this obscurity throwing some doubt upon the accuracy of all altitudes measured after dark. The winds and currents of the ocean have a material influence upon the speed of ocean voyages, even with modern steamers. With sailing vessels they are most important, and are truly said to control the mariner in his course; to know how to steer a ship so as always to make the most of them is the perfection of navigation. The approaches to the ports and the appearance of the land in their vicinity are described in local Sailing Directions, which are very complete for all parts of the globe, and are the guides for entering port and anchoring.

Navigation Laws, enactments by which commercial states endeavor to regulate navigation so as to promote their own commerce. Such laws have existed among all the maritime states of Europe for many centuries. The navigation laws of England, so called, date from Cromwell's time. They provided that no ship should be deemed British unless wholly built in British dominions, wholly owned by British subjects, and navigated by a British commander and a crew of which at least three fourths were British subjects; that only British ships should carry any merchandise from one port to another, where both were in the British Empire; and that no goods which were the growth, product, or manufacture of Asia, Africa, or America should be imported into Great Britain except in British ships or in ships of the countries of which the goods were the production. These laws are supposed to have done much to give Great Britain her enormous commerce. Since 1849 the principle of free

NAVY

trade has caused them to be considerably modified. In the U. S., Congress enacted navigation laws, 1792-93, which are substantially the same as the English acts then in force, or, where they differ, more rigorous. These statutes have not been materially altered. See also INTERNATIONAL LAW.

Nav'igator's Is'lands. See SAMOA.

Na'vy, a fleet or assemblage of ships or vessels; specifically, the whole of the war vessels of a nation; the war marine of a state. Navies have grown out of either military necessities or the requirements of an ocean commerce obstructed by pirates. Trade and navigation may be said to be the parents of navies, those countries most largely interested in the former generally boasting of the most powerful fleets. While foreign trade produces wealth, and at the same time trains a class of men to the hardships of the sea, it requires protection and assistance in return. This is rendered by the military marine, whose service is largely recruited from the commercial. A navy proportioned to the commercial tonnage of a country and the extent of its shore line is the best and least expensive protection to the coasts and commerce of that country. Since an efficient naval force (unlike an army) cannot be improvised, every maritime state has found it necessary to maintain a permanent navy; and such navies have seldom lent themselves to the subversion of the political organization of the state. Besides the ordinary duties of policing the seas to keep down piracy and of affording a moral support to ministers at foreign courts and merchants in foreign trade, navies are constantly engaged in the fields of science, and have contributed generously to the common stock of knowledge and the advancement in civilization.

The Constitution of the U. S. imposes on Congress the duty of providing and maintaining a navy, and of making rules for the government and regulation of the naval forces. It declares the President to be commander in chief of the army and navy, and requires him to commission all officers of the U. S. The Secretary of the Navy presides over the Navy Department, and is the duly constituted adviser of the President on all questions relating to naval affairs. In his former duties he is assisted by an Assistant Secretary and the chiefs of eight bureaus, as follows: Equipment, Yards and Docks, Navigation, Ordnance, Medicine and Surgery, Supplies and Accounts, Steam Engineering, and Construction and Repairs.

Vessels are named by the Secretary of the Navy, under direction of the President, as follows: First rates, after the states of the Union; second rates, after cities; third rates, after important events or names connected with the naval history of the U. S.; fourth rates, after lakes and rivers of U. S. Modern warships include the following types: Armored vessels for the line of battle and for coast service, armored cruisers, rams, protected cruisers, unarmored cruisers and auxiliaries, gun vessels, gunboats, torpedo vessels, torpedo catchers, torpedo boats, and various vessels for harbor service. The following table gives a