GYULA 



I MECHANISM 

 I CONTROLLING 

 1 COMPRESSED 



PETROL MOTOR 



' DRIVE GYROSCOPES 



Gyroscope. 



"Diagram illustrating the mechanism and construction of the Brennan monorail, which owes its stability 

 on the rail to the use of gyroscopes 



pair of leaves. It grows on banks of 

 streams and ditches, and the juice 

 makes a rich brown stain. 



Gyron (Fr.). In heraldry, a 

 wedge, formed by a diagonal line 

 from the dexter chief meeting a 

 horizontal line in the 

 fess point. It is one 

 of the sub-ordinaries 

 (q.v.). When a shield 

 is divided by a series 

 of wedges it'is said to 

 be gyronny. Usually 

 there are eight gjTons, 

 but there may be 

 only six, or as many as sixteen. 

 Such irregularities should always 

 be specified. 



Gyroscope (Gr. gyros, circle; 

 skopein, to look). Originally name 

 of a scientific toy used to demon- 

 strate the forces acting on rotating 

 bodies. It is now extended to 

 various devices which depend on 

 gyroscopic forces. 



The gyroscope consists usually 

 of a heavy fly-wheel spinning at a 

 high speed, supported on an axis at 

 right angles to the plane of the 

 wheel. Its motions and applica- 

 tions depend on the fact that if 

 any body, symmetrical about an 

 axis of greatest or least moment of 

 inertia, is set rotating about that 

 axis, then the direction of the 

 latter remains unchanged in space 

 unless external forces are applied. 

 As examples of gyroscopic motion 

 may be cited the wheels of a bicycle 

 when in motion, the turning of a 

 propeller of an aeroplane, and the 

 spinning of a rifle bullet or shell, 

 enabling it to keep its general 

 direction unaltered. 4 



The applications of the principle 

 of the gyroscope are numerous and 

 important. The gyro-compass de- 



pends upon the stability of the 

 motion ; the directing of torpedoes 

 is due to the gyroscope. 



The Sperry aeroplane stabiliser 

 consists of a gyroscope driven 

 from the engine shaft. It is con- 

 nected with the controls and auto- 

 matically operates them against 

 the tendency to roll, etc. The gyro 

 turn indicator used in aeroplanes 

 is driven at high speed by the air 

 as the machine is flying, and gives 

 warning of the machine turning. 



The increasing use of steel and 

 iron on board ship, especially naval 

 vessels, made the ordinary mag- 

 netic compass unreliable, and many 



Gyroscope in its simplest form. 



While spinning, the top remains 



steady on the string 



attempts have been made to replace 

 it, the most successful being a gyro 

 compass. This consists of a heavy 

 horizontal spinning disk revolving 

 in a vacuum at 8,000 or more revo- 

 lutions a minute. The axis of the 

 gyro wheel is connected with the 

 pointer of a compass card, and so 

 any deviation of the ship's course 

 is at once measured. Gyro-com- 



passes are usually placed in the 

 body of the ship, below deck, and 

 connected by transmitters to re- 

 peating compasses on the steering 

 platform, bridge, etc. 



In 1907 Louis Brennan exhibited 

 before the Royal Society a device 

 for the application of the gyroscope 

 to monorails. In such a system the 

 cars are supported o'n single 

 wheels, equilibrium being main- 

 tained by a gyroscope revolving at 

 high speed in a vacuum. Since 

 then a number of monorail systems 

 working on the gyroscopic principle 

 have been tested in Great Britain, 

 U.S.A., and Germany. See Bren- 

 nan ; Torpedo. 



Gythium. Ancient Greek city, 

 in Peloponnesus. It stood at the 

 mouth of the river Gythius, on the 

 N.W. shore of the Bay of Laconia, 

 27 m. from Sparta, whose port it 

 was. As the headquarters of the 

 Spartan fleet it was often attacked ; 

 the Athenians burned it in 455 B.C. 

 It was a member of the Achaean 

 League (q.v.) from 195 B.C. until 

 146 B.C. Excavations have brought 

 to light the remains of a Greek 

 theatre and Roman ruins, but 

 much of the ancient city lies be- 

 neath the sea. Marathonisi is the 

 modern town. 



Gyula. Town of Hungary, the 

 capital of the co. of Bekes. It 

 stands on the White Koros river, 

 which bisects the town, 36 m. 

 N.N. W. of Arad. Formerly strongly 

 fortified, it has a museum contain- 

 ing antiquarian relics, the ruins 

 of an old castle, and a chateau. 

 There is trade in wine, oil, flour, 

 and spirits, while cattle are reared 

 in the neighbourhood. Turtles 

 are caught in the surrounding 

 swamps. Pop. 24,284. 



