GALVESTON 



341 2 



GALWAY 



Galvanometer. D'Arsonval moving 

 coil type. Left, the instrument with 

 case removed. Right, diagram show- 

 ing chief parts. A, permanent 

 magnet ; B, coil ; C, soft iron 

 cylinder concentrating magnetism 

 on the coil ; D, mirror ; E, gravity 

 damper 



is passed through the coil a mag- 

 netic field is established which acts 

 upon the permanently magnetised 

 needle and causes it to deflect in a 

 direction and to an extent varying 

 with the direction and strength of 

 the electric current. Great sensi- 

 tiveness may be obtained in the 

 " moving-needle " type of galvano- 

 meter, but the magnetic field of 

 the instrument is easily disturbed. 

 This defect may be mitigated by 

 employing two needles and two 

 coils, the needles being so arranged 

 that the effect of magnetism, other 

 than that of the coils, is neutralised. 



A less sensitive, but much used, 

 type of galvanometer has fixed 

 permanent magnets and a moving 

 coil. The current is conducted to 

 the suspended coil through the sus- 

 pensions, the stationary permanent 

 magnet system producing a mag- 

 netic field so strong as to be little 

 affected by external influences. 



For delicate work the deflection 

 is enormously magnified by the use 

 of a small mirror, which reflects a 

 beam of light on a distant scale. 



The resistance to the deflection 

 of the pointer or the mirror, as the 

 case may be, is adjusted by a per- 

 manent magnet, by gravity, or, 

 when the moving portion is sus- 

 pended on a fibre, by the torsion of 

 the material. Excessive swing of 

 the moving parts is " damped " by 

 a light vane of mica or aluminium. 



For measuring alternating cur- 

 rents an ordinary galvanometer is 

 obviously unsuitable, but alternat- 

 ing currents have been indirectly 

 measured by their heating effect in 

 the coil which generates direct cur- 

 rent in a thermo-couple. One form 

 of alternating - current galvano- 

 meter depends for its action upon 

 the untwisting of a strip by the 

 heating action of the current. In 

 another the Einthoven " string " 

 galvanometer a very fine silver 

 wire lies between the poles of an 

 electro-magnet, which is independ- 

 ently excited. An alternating cur- 

 rent passing through the wire 



causes it to vibrate ; the amplitude 

 of the vibrations is observed by a 

 microscope or by luminously pro- 

 jecting an en- 

 larged image 

 of them upon 

 a screen or 

 photographic 

 plate. See 

 Ammeter ; 

 Voltmeter ; 

 Meter,Electric~ 

 Galveston. 

 City and port 

 of entry of 

 Texas, U.S.A., 

 the co. seat of 

 Galveston co. 

 Situated at 

 the N.E. end 

 o f Galveston 

 Island at the 

 entrance to 

 Galveston 

 Bay, it is 49 m. 

 S.E. of Hous- 

 ton, and is 

 served by several rlys., including 

 the Galveston, Houston and Hen- 

 derson, which connect the city with 

 the mainland. Galveston is the 

 leading port of the Union for the 

 exportation of cotton, and is a 

 flourishing seaside resort. 



The principal buildings include 

 the court house, city hall, Y.M.C. A. 

 building, custom house, post office, 



Galveston. Part of the docks of the Texas seaport 

 and public library. Among the 

 educational institutions are S. 

 Mary's University, the state medi- 

 cal college, the Ball high school, the 

 cathedral school, the central high 

 school for coloured students, the 

 Ursuline convent, the Sacred Heart 

 academy, and several public 

 schools. The city is well provided 

 with benevolent institutions, and 

 the government maintains a marine 

 hospital and quarantine and immi- 

 gration stations. 



Galveston has regular steamship 

 communication with Europe ,Asia,S. 

 America and the ports of the U.S.A., 

 and its annual foreign trade is valued 

 at upwards of 60,000,000. Cotton 

 accounts f ormore than three -fourths 



of the exports, next to which 

 come wheat, cotton-seed cake, 

 cotton-seed oil, and linseed cake. 

 Other products shipped are flour, 

 machinery, lumber products, and 

 agricultural implements. The lead- 

 ing imports are coffee, sugar, corn, 

 cattle, and bananas. Pop. 42,650. 



Galveston was first visited by 

 Spaniards about 1781, by whom it 

 was called Galveston probably in 

 honour of Bernardo de Galvez, 

 governor of Louisiana. During the 

 Civil War it was blockaded by the 

 Federal navy, which occupied it on 

 Oct. 8, 1862, but capitulated to the 

 Confederates on the first day of the 

 following year. In 1885 the city 

 was badly damaged by fire, but a 

 far greater catastrophe was the 

 1900 hurricane, the city being in- 

 undated to a maximum depth of 16 

 ft., 8,000 persons losing their lives, 

 and 4,000,000 damage being done 

 to property. Since then a massive 

 sea-wall and a concrete causeway 

 connecting the island with the 

 mainland have been constructed, 

 and the city has been lifted in some 

 parts 19 ft. above its original level. 

 In 1901 Galveston instituted the 

 commission form of local govern- 

 ment, widely adopted in the U.S.A. 

 Galveston Bay. Inlet of the 

 Gulf of Mexico. Protected by the 

 island of Galveston and by a nar- 

 row promontory stretching W.S.W., 

 . it extends inland 

 for about 35 m. 



Galvez, MARI- 

 ANO (1795-1855). 

 Guatemalan poli- 

 tician. Born in 

 Guatemala, he be- 

 came an active 

 politician, being 

 one of those re- 

 sponsible for the 

 constitution of 

 1824. In 1825 he 

 was president of 

 the first congress 

 of the Central 

 American states. 

 From 1831 to 1838 

 he was president of Guatemala, but 

 he lost his power in 1838 and was 

 soon exiled. Henceforward he lived 

 mainly in Mexico and Peru. 



Gal way. County of Ireland. 

 In the province of Connaught, its 

 area is 2,370 sq. m., making it the 

 second largest of 



the Irish coun- 

 ties. It has a 

 coast-line of 

 about 400 m. on 

 the Atlantic, 

 where are several 

 bays with excel- 

 1 e n t harbours, 

 and off which 



are a number of islands ; the former 

 include Killary, Kilkieran, and 



Calway arms 



