Page:The New International Encyclopædia 1st ed. v. 01.djvu/636

ANDUJAR. Morena. It is quite a prosperous, modern-looking city, with tine churches, four nunneries, six monasteries for men, three hospitals, and a theatre. A fine promenade runs through the town. There is some trade in grain, cattle, and wine. Andújar is frequented for the mineral springs in its neighborhood. Pop., 1900, 16,411.

ANDVARI, and-va're. In Norse mythology, the name of the fish-shaped dwarf who owned the ring, with the curse of ill-obtained gold, fatal to the possessor. This is the key-note of the remarkable stories of Sigurd Fafnisbane and the German legends presented in musical form by Wagner in an elaborate tetralogy, consisting of Das Rheingold (the temptation), Die Walküre (Fate), Siegfried (the hero), and Die Götterdämmerung (the "Twilight of the Gods," or end of all things).

AN’ECDOTE (Gk. ἀνέκδοτος, anekdotos), unpublished, from ἀν, an, negat. + έκ, ek, out + διδοναι, didonai, to give). Procopius called his secret history of Justinian's court Anecdota. The name is applied also to portions of ancient writings long unpublished, and a number of such Anecdota have been collected in volumes and printed. As ordinarily used, anecdote now means some isolated fact, usually of a personal nature, which would interest a listener. There are a great many books of anecdotes, the most celebrated in English being the Percy Anecdotes.

ANEL'IDA AND AR'CITE. A poem by Chaucer, called also Queen Anelida and False Arcite. Anelida is an Armenian queen; Arcite a knight of Thebes. The work is unfinished, but was printed by Caxton. Parts of it have been recognized as taken from Statius's Thebaid and Boccaccio's Teseide. Chaucer himself acknowledged obligation to Statius and Corinna, a Greek poetess of the fifth century B.C. There is a modern version by Elizabeth Barrett Browning.

ANEM'OGRAPH (Gk. ἀνεμοσ, anemos, wind + γράφειν, graphein, to write, record). When a wind-vane is attached to self-recording apparatus it becomes an anemograph. Frequently the anemometer for measuring the velocity of the wind is also made to register upon the same sheet of paper and the apparatus becomes a complete anemograph. As the paper moves uniformly by clock-work, every change of the wind as to direction or velocity is registered at the πroper time. The anemograph is called a wind-register in the Weather Bureau, but the word itself is retained in European literature.

AN'EMOMETER (Gk. ἀνεμοσ, anemos, wind + μέτρον, metron, measure). An instrument used to measure the velocity of the wind, its pressure, or other effects produced by it. The first instrument of this kind is commonly known as Hooke's pendulum anemometer, and is mentioned as early as 1667. It is, however, likely to have been the common product of the members of the first meteorological committee of the Royal Society of London, among whom Hooke and Sir Christopher Wren were prominent members. This form of instrument was revived in 1861 by Professor H. Wild, and is now used in Switzerland and Russia, where it is known as Wild's tablet anemometer. In this instrument a plane square tablet is suspended vertically from a horizontal axis which is kept by a wind-vane always at right angles to the direction of the wind; the tablet is raised by the wind to an inclined position of temporary rest, and its angular inclination to the vertical is noted on a graduated arc; circular plates, and especially spheres, have been sometimes used instead of the plate. About 1724 the use of a vertical pressure plate, having springs or weights at its back against which the plate is pushed by the wind, was introduced by Leupold; at the present time the pressure plate anemometer is used at a few European observatories in the form arranged by Osler for the British Association for the Advancement of Science. Theoretically, the most perfect modification of Leupold's anemometer is that devised by Jelinek in 1850, in which the springs behind the pressure plate are inclosed in a cylindrical case, which eliminates the action of the wind or the partial vacuum at the back of the plate. A third class of pressure-anemometers is that of Lind, in which the wind-pressure acts on the surface of a liquid in a U-shaped tube, raising it in one leg of the U and depressing it in the other.

Various other forms of pressure-anemometers have occasionally been used by meteorologists, but at the present time the tendency is to abandon all these in favor of instruments that rotate and give more or less correctly the velocity of the wind. This tendency is justified by the consideration that in meteorology we need only the velocity of the wind, and by the fact that, although the engineer needs to know the pressure of the wind against engineering structures, yet he cannot obtain this with sufficient accuracy from the pressures recorded by the small flat surfaces that are used in ordinary anemometers. In fact, the pressure of the wind against an obstacle depends not merely on the area of the transverse section of that obstacle, but on the shape of that section, and even still more on the longitudinal section in the direction of the wind. Thus, the pressure of the wind on wires, ropes, and rods is much greater than on globes of the same transverse section; the pressure on a triangle is greater than that on a square or circle of the same area. In general, it is more important to know the velocity of the average wind and of its maximum gusts than to know its pressure on some assumed arbitrary solid. When rain is driven with the wind, the combined pressure due to both is needed in engineering studies.

Anemometers for measuring wind velocity include both the suction-anemometers and the rotation-anemometers. In the former the open end of a long, vertical tube is freely exposed to the wind in such a way that it blows as nearly as may be transverse to the axis of the tube. The end may be fitted into the side of a horizontal contracted tube as in Venturi's instrument; or may end conically in the air, or squarely, and without any adjunct. The passage of the wind across the open end of the tube produces a diminution of barometric pressure within it, which increases with the velocity. The exact measurement of this depression gives the basis for computation of the velocity of the wind. This principle was known to the experimenters of the American Academy of Arts and Sciences (see their report for 1847), and to those of the Franklin Institute (see their report of 1842), and is that which explains the draught up a good chimney; but it was first applied to the measurement of the wind in England by Fletcher in 1867. The modifications of Fletcher's anemometer