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Rh being weighted by means of the foot and body of the performer at first and later by means of weights; the reed organ, consisting of pipes furnished with beating reeds, known also as the reed work when incorporated with the large church organ; the medieval portative and positive organs; the large modern church organ. To this class also belong the accordion and concertina and the numerous instruments of the harmonium type which have free instead of beating reeds, a difference which confers upon them the power of dynamic expression denied to all organs fitted with flue pipes or pipes having beating reeds. The complex instruments known as organized pianos also come within this category.

2. This comprises the bagpipes known as musette, and the Union or Irish and the Border bagpipes having a wind supply fed by bellows instead of by the insufflation pipe proper to the bagpipe; the barrel organ having instead of a keyboard a barrel studded with nails, which lift the valves admitting air to the flue pipes generally hidden within the case.

 WINDISCHGRÄTZ, PRINCE ALFRED (1787-1862), Austrian field-marshal, entered the Austrian army in 1804, participated in all the wars against Napoleon and fought with distinction at Leipzig and in the campaign of 1814. In the following years of peace he held successive commands in Prague, being appointed head of the army in Bohemia in 1840. Having gained a reputation as a champion of energetic measures against revolution he was called upon to suppress the insurrection of March 1848 in Vienna, but finding himself ill-supported by the ministers he speedily threw up his post. Having returned to Prague he there showed firmness in quelling an armed outbreak of the Czech separatists (June 1848). Upon the recrudescence of revolt in Vienna he was summoned at the head of a large army and reduced the city by a formal siege (Oct. 20-29). Appointed to the chief command against the Hungarian rebels he gained some early successes and reoccupied Budapest (Jan. 1849), but by his slowness in pursuit he allowed the enemy to rally in superior numbers and to prevent an effective concentration of the Austrian forces. In April 1849 he was relieved of his command and henceforth rarely appeared again in public life.

See ''Fürst Windischgrätz. Eine Lebens-Skizze. Aus den Papieren '' eines Zeitgenossen der Sturm-Jahre 1848 und 1849 (2nd ed., Leipzig, 1898).  WINDMILL, a term used, in the widest sense, for a machine by which the energy of the wind is applied to useful purposes. 1.—Windmill near Delft. Windmills were certainly used as early as the 12th century and are still largely employed in Holland in draining the polders and grinding trass. They are somewhat extensively used in America for pumping and driving agricultural machinery. In spite of the competition of more powerful and tractable motors, they are serviceable, especially in new countries, where fuel is scarce and where work can be done intermittently. An inquiry was made in India in 1879 as to the possibility of using windmills for irrigation (Professional Papers on Indian Engineering, July 1879), with the result that it was concluded their usefulness would be very limited.

A windmill is not in any case a very powerful or efficient

motor, and its work is variable and intermittent. In favourable positions, it will run on an average for eight hours out of the twenty-four. For pumping on a small scale, the intermittent action is least an objection, because there is generally a tank or storage reservoir regulating the delivery of the water. For driving dynamos windmills are least suitable, on account of the variation of speed, though some attempts to generate electricity by wind power have been made, special arrangements being adopted for automatically regulating the speed.

European Windmills.—In all the older windmills a shaft, called the wind shaft, carried four to six arms or whips on which long rectangular narrow sails were spread. The wind shaft was placed at an inclination of 10° or 15° with the horizontal, to enable the sails to clear the lower part of the mill. The whip carrying the sail was often 30 to 40 ft. in length, so that the tips of the sails described a circle 60 to 80 ft. in diameter. The sails were rectangular, 5 to 6 ft. wide, and occupying five-sixths of the length of the whip. A triangular leading sail was sometimes added. Sometimes the sails consisted of a sail-cloth spread on a framework; at other times narrow boards were used. The oldest mill was no doubt the post mill, the whole structure being carried on a post; to bring the sails to face the wind, the structure was turned round by a long lever. The post mill was succeeded by the lower, smock or frock mill, in which the mill itself consisted of a stationary tower, and the wind shaft and sails were carried in a revolving cap rotating on the top of the tower. Andrew Meikle introduced in 1750 an auxiliary rotating fan at right angles to the principal sails, which came into action whenever the wind was oblique to the axis of the sails, automatically veering the sails or placing them normal to the wind. For safety, the sails must be reefed in high winds. In 1807, Sir W. Cubitt introduced automatic reefing arrangements. The sails were made of thin boards held up to the wind by weights. If the force of the wind exceeded a certain value the boards were pressed back and exposed little surface.

American Windmills.—These generally have the sails, 18 or more in number, arranged in an annulus or disk. The sails consist of narrow boards or slats arranged radially, each board having a constant or variable inclination to the wind's direction. An American mill presents a larger surface for a given length of sail than the older type, and consequently the construction is lighter. To turn the mill face to the wind a rudder is sometimes used projecting backward in a plane at right angles to the plane of rotation of the sails. Various arrangements are adopted for reefing the sails automatically. (a) In some an action equivalent to reefing is obtained by turning the sail disk oblique to the wind. The pressure on a side vane in the plane of rotation, controlled by a weight, turns the sail disk edgeways to the wind if the pressure exceeds a safe amount. (b) In centrifugal governor mills the slats forming the sails are connected in sets of six or eight, each set being fixed to a bar at the middle of its length. By rotating this bar the slats are brought end on to the wind, the action being analogous to shutting an umbrella. The slats are held up to the wind by a weight. A centrifugal governor lifts the weight if the speed becomes excessive and the sails are partially or completely furled. Many of the veering and reefing arrangements are very ingenious and too complicated to be described without detailed drawings. A description of some of these arrangements will be found in a paper by J. A. Griffiths (Proc. Inst. Civ. Eng., 119, p. 321) and in a “Report on Trials of Wind Pumping Engines at Park Royal in 1903” (Journ. Roy. Agric, Soc., 64, p. 174).

Warner's Annular Sail Windmill.—Messrs Warner of London make a windmill somewhat similar to American mills. The shutters or vanes consist of a frame covered with canvas, and these are pivoted between two angle-iron rings so as to form an annular sail. The vanes are connected with spiral springs, which keep them up to the best angle of weather for light winds. If the strength of the wind increases, the vanes give to the wind, forcing back the springs, and thus the area on which the wind acts diminishes. In addition, there are a striking lever and tackle for setting the vanes edgeways to the wind when the mill is stopped or a storm is expected. The