AQUEDUCTS

in the domain of pressure conduits for water supplies, cast-iron pipe continues to be most in favour in great britain on account of its durability, but the trend of recent development is towards the substitution of riveted or welded steel for cast iron especially for medium and large sizes, and for situations where settlement of the ground is expected. the advantages of steel are its lightness, reliability, water- tightness and security from cracking, and experience now shows that well-coated steel pipe when buried in normal soil will endure for many years. examples exist of pipes about 75 in. thick which are still in use after 40 years service. 149 pipe linings.—efforts have been directed for some time by manufacturers towards the application to steel and iron pipes of an interior lining which will permanently adhere and prevent rusting, pitting and incrustation. ‘the bases of two such lin- ings, which are put on by a process of centrifugal spinning, are portland cement and bitumen, and experience is now being accumulated as to their endurance under various conditions. the new pipe-line ' from lake tansa for the bombay water supply is a good example of riveted steel construction for pipes of 57 in. to 72 in. diameter under moderate head. the pipe is formed of single plate rings 34 in. thick and 7 ft. 4 in. long, alter- nately in and out, with the longitudinal joints double riveted and circumferential joints single riveted. hydroelectric aqueducts (see hydrorlectric engineering) .— the greatest developments in aqueduct construction in recent a a duaulbn: wibttag ssa nop a f dig in, fig. 4. “bump” joint fi g.3. spigot & socket riveted joint years have taken place in connection with hydroelectric power supply schemes. almost every class and size of conduit is con- cerned, from enormous open canals, lined and unlined, to tun- nels and great pipes of steel, wood or concrete for moderate pressures and smaller pipes of stecl for high heads up to over 5,000 feet. | canals.—a concrete-lined canal for conveying water to the low head power station at beaumont monteaux on the basse ise¢re, france (fig. 1), is rog {t. wide on the bottom with 15 ft. maximum depth of water, side slopes of 1 to 1 and cement con- crete lining 12 in. thick on floor and sides, finished with a surface rendering of cement mortar 1} in. thick. the ning is laid in sections with a transverse expansion joint every 23 feet. ‘the maximum flow is 10,000 cusecs and maximum average velocity 64 ft. per second. the fall is 1 in 6,400. at the humber arm iydro-electric works of the newfound- land power and paper co. there is a large unlined canal in con- junction with seven large wood-stave and steel pipe-lines for a maximum head of 230 feet. the canal has a base width of 100 © {t. and water depth of 21 ft. for a minimum winter flow of 5,000 cusecs. a typical cross-section is shown in fig. 2, which also indicates the restriction of water area expected in winter from the formation of thick ice. the lessened water area and increased wetted surface together give rise to serious reduction of capacity which must be allowed for in regions such as this, which are sub- ject to severe and prolonged frost. the gradient is 1 in 7,450 and the maximum velocity of flow is about 3 ft. per second. the dimensions of this unlined canal should be compared with those of the lined canal at beaumont montecux designed for a flow twice as great. wood stave and riveted steel pipes —each of the seven pres- sure pipe-lines is formed of an upper part in wood-stave con- struction and a lower part of steel riveted construction. the wood-stave portion is used up to a maximum head of 167 it. and is g ft. 6 in. diameter with machined staves 3} in. thick in widths of 54 in., and having mild steel bands ? in., 7 in. and 1 in. 1 engineering, oct. 7 1924. 150 aqueducts diameter at spacings varying from 27 in. to 8 in. it is carricd on | coefficients may be taken as -o12 to -or4 for concrete lining, and piled foundations at intervals of 12 ft. 6 in., the direct support | provisionally as -o24 to -032 for unlined tunnels. where the being on curved cradles of reinforced concrete formed over the piles (fig. 8). the riveted steel portion has diameters of 9 ft. 6 in. and 8 ft. 6 in. and thickness from 3% in. to 12 inch. the maximum flow ez) & ——————— ae — fig.5. flanged § bolted joints. fig. 6. sy fi ss ~ . > xia? os w gv : =a with re of 8 tns my fe yay sup mes ste tins teg) neo fnal fig. 7. drac-romanche conduit. and velocity are 550 cusecs and 9.7 ft. per sec. respectively. the pipe is formed in rings § ft. long alternately in and out, each ring being made with two plates and having two longitudinal lap joints. the pipe-lincs are protected with a bituminous coat- ing and surrounded with earth as protection against freezing. covered conduits and tunnels —free-flowing contour con- duits, where practicable on steep hillsides, are usually made rectangular in concrete or reinforced concrete and covered over as protection against slides and rock falls. tunnelling is, how- ever, often preferred on the score of shorter distance with less loss of head, less risk of accident and smaller cost of maintenance. free-flowing tunnels are commonly lined with concrete on bottom and sides, but not on the roof if the rock is sufficiently sound. low-pressure tunnels.—low-pressure tunnels are now largely uscd in mountainous districts to convey the water from the reservoir or intake to the top of the high-pressure pipe-line while conserving the maximum possible head. in hard, sound un- fissured rock they may be unlined, but lining of rich concrete, in conjunction with sealing of fissured places by injection of cement through drill holes, is generally desirable. the hydraulic flow conditions in unlined tunnels are very uncertain and smooth concrete lining is often used on this account alone. kutter’s o, fae go ae ~ ge ss ims vaasee r air fic. 8.—pipe constructed of wooden staves and steel hoops. fa weight of rock cover over the tunnel is not sufficient to balance the water pressure, the lining may have to be reinforced to with- stand the pressure, and the possibility of water under pressure finding its way into extensive fissures must be guarded against. high-pressure welded pipes—high pressure portions of pipe- lines are now almost exclusively made of hammered lap-welded mild steel in lengths up to a maximum determined by the rolls available for bending the plates to circular form, lengths of 20 to 26 ft. being common. with suitable welding apparatus having long reach, two or three such lengths can be joined together by circumferential welded joints to make single smooth-bore pipes of 40 to 60 ft. in length. such pipes have less weight, offer less resistance to flow and require less field work for installation as compared with riveted pipes. the steel used requires to be of extra mild, ductile and weldable quality for which, when allow- ance of about 90% efficiency for the welded joint is made, a working tensile stress of about 5 tons per sq. in. is appropriate. a hydraulic test to at least 50% but preferably to 100% above the working pressure should be made on each pipe at the maker’s works. the joints form a vital part of a high-pressure pipe and the trend of development is to make them strong and rigid, and avoid the use of bolted, packed and expansion joints wherever possible. welded pipe with riveted end joints represents, for medium and large-size pipes, the best modern practice, the rivet- ing being single, double or treble, according to the pressure which may be applied. two forms of riveted joint are shown in figs. 3 and 4. fig. 3 shows a spigot and socket form turned and bored to slight taper to ensure perfect fit and water tightness. fig. 4 shows the so- called “ bump ” joint with coned and swelled ends, arranged so that the rivet heads do not project within the skin of the pipe. for the smaller sizes, where the room inside is too cramped to permit proper riveting, flanged and bolted joints of various types are used, generally with a packing ring to ensure watertightness. wo broad classes of joint may be noted: (1) (anges rigidly fixed to the pipe by riveting, welding or screwing; (2) a pair of loose flanges bolted together so as to grip the swelled or slightly flanged ends of adjacent pipes. typical forms of the two classes are shown in figs. 5 and 6. welded pipe, and especially bends and junction pieces, are manufactured with great difficulty when the thickness exceeds 1% inches. usually the thickness can be kept within necessary limits by sub-division of the flow, but for exceptional cases weld- ed pipe, with weldless steel bands shrunk on at intervals, has been used. the thickness of the tube is then fixed from consid- erations of manufacture and the additional strength required to resist bursting is furnished by the bands. the tube must be of extra mild, weldable steel; the rings may be of ordinary or high tensile steel. security afeasures.—high-pressure pipe-lines and precipitous and difficult locations usually go together. security of installa- tion is of the utmost importance in view of the serious damage that may follow the release of great uncontrolled power due to failure. the principal forces to be dealt with are the weight of the pipe and contents, and the inclined components thereof which cumulatively may be very large, the outward thrust at bends arising from the water pressure, and the large, longitudinal forces of tension and compression produced by changes of temper- ature. the latter forces can only be modified by the introduction of expansion joints, they cannot be eliminated. two contrasting methods of installation are in use, which may be designated the swiss and the french method respectively. in the swiss method a heavy concrete anchorage surrounding the pipe is provided at every bend, horizontal or vertical, the pipe-line being thus divided into a series of straight lengths, each of which is provided with an expansion joint near its upper end. the anchorages are designed to resist the maximum forces transmitted by the section of pipe-line attached thereto. in the french method main anchorages are provided at top and bottom only, there are no expansion joints, subsidiary intermediate arabia anchorages are provided to hold the pipe in position and take care of the stresses produced by local variations of temperature and generally bends and elbows are left free to spring somewhat under extremes of temperature. there are numerous successiul examples of each method, one of the latter class worthy of mention being the pressure pipe- line of the eget station in the pyrenees. the fall is about 2,470 ft. and there are seven parallel pipes of 22 in. diameter serving seven pelton wheels, each of 5,000 horsepower. there are no expansion joints, and the final joining up was done at medium temperature to limit the range of dilatation and contraction stresses. pipes were used in lengths of about 40 fit. with heavily bolted flanges of the type shown in fig. 6. the pipes rest on inclined metal saddles which are bolted to the tops of concrete or masonry piers about 3 ft. thick. reinforced concrete pressure conduits.—reinlorced concrete is finding increasing use for low-pressure pipes and conduits, there being definite advantages on the score of maintenance and security against collapse from partial vacuum together with, in suitable cases, a saving in first cost. essential requirements to success are fine, well-graded aggregate and sand, with a rich admixture of cement, and careful and thorough mixing and work- ing into place, all combined with careful designing and proper disposition of reinforcement to take account of principal and secondary stresses in both the circumferential and longitudinal directions. for moderate diameters and pressures, precast, re- inforced concrete pipe with joints of the “‘ lock joint ” or other special type and in lengths up to 12 ft. has found considerable use. the site must be accessible as the weights are heavy. for large diameters the conduit is manufactured ‘in situ.” probably the largest reinforced pressure conduit yet constructed 35° caders usale aly. i. veoiterranean si qs pols, yi [4 .< eo, s i5i is that of the drac-romanche hydroelectric development at pont de claix near grenoble, france. the diameter is 19-7 ft. and the section is as shown in fig. 7. the outer mould for the lower half of the reinforced tube is formed of mass concrete, steel shuttering being used for the rest of the construction. the fine concrete for the tube was mixed in the approximate propor- tions of 500 kgm. cement; .400 cu. metres sand; .800 cu. metres ageregate, say by volume 1:1-1:2-2. the maximum head is about so ft., maximum flow and velocity 2,800 cusecs and 9-2 ft. per sec. respectively and loss of head about i metre in 1,500 metres. a covering of earth serves to minimise temperature variations. (j. wi.) arabia (sce 2.254).—by the end of 1925 considerable pro- gress had been made toward determining the political boundary of arabia on the north. in 1921 the boundary between nejd and kuwait was fixed by agreement between ibn sa‘ud and the high commissioner for ‘iraq. in the same year the boundary between nejd and ‘iraq was fixed at the conference of moham- merah. in oct. 1925 a british mission under gen. sir gilbert clayton visited ibn sa‘ud in the hejaz to fix the boundaries between nejd and transjordan. the northern boundary resulting from these arrangements is as follows: starting near haq] on the gulf of 'agaba it runs eastwards, south of mudawara station on the hejaz railway, to the 38th meridian. thence from lat. 30° it strikes northwest to ‘amari wells leaving all wadi sirhan to nejd. thence it runs east to jabal ‘anaiza leaving a corridor of british mandated territory between nejd and syria. and thence it follows the ‘iraq-nejd boundary ina southeast direction through the batu depression and the wells of ansab to riqa‘i in the batin valley, whence it circles round the kuwait principality to the persian gulf coast. in the southwest corner of arabia the boundary between the aden protectorate and yemen was delimited by an anglo-turkish com- ve. ¥ 4. &al kuwait). j es 2“. @ + 9 u ; ae . n * 2, * ye ===-et—5b8 cee * “ pp 2 2 ; cf ae. on ¥k gp amma ” . } roy lp 7 tah f. ; jbar gs lohan yg ae gatif 4 rae {b ) : wagrns knl a anaizd®s sudair © ty nee 7 7 7 : 3 on pou sf doha — up eso = [an 1 ran washm oshagra ~ehufufio y = 3 som pinas2f-o nf te =, i aa rr 115 0 te tse 7s bie ke <, ae 3 ime _ medina arid riyadh smes | 3 scabs 4 yen 088 titm~” * pf ~2 * 4 4 os aetna 0 vy “ip, yan 0 @ - has! iq kharj ox *wad! hanifa bis. matha eran see ee ne sue 8 es saver rast 7 na e. v -_= : es as -f skhurma 7 > reus 4 10 1e€cca a *f oe , 1 | 4°7arf turab a 358° if . "» i 26 a lgguey rubt| al khall ——masira fi a wadi dawasir masira 8. = al ahkaf desert a= . farasary (s3gi2k . | ao es = ahawan . shibar, jie £ pp, a ‘ sooan cl ) 9 res english miles sete a oren =o pa ato os oi kilometres er oo s/o (5) a a ee sonar s ez os a 9 100 200 300 mochal 50/8 < nd aatlways an 4 state boundaries banna teen neutral yy raster: an ee ~et longitu / man at tee a 4 th sgians wb 8 paz 7 hi nai fen 6.-0f “a de n——abd el kurie deb i= socotra pee coe aa ee re ee de east 45° of greenwich cg 152 mission in 1902-4, and runs from a point opposite perim island in a roughly northeast direction to qa‘taba beyond which a due north- east line continucs it into the virgin desert. apart from these frontiers the land boundaries of the various arabian states are inde- terminate. (lisr..). be ps i. exploration and topography in roo4 dr. d. g. hogarth in the penetration of arabia gave a full history of the exploration of the peninsula up to that date. since then considerable progress has been made in the explora- tion and mapping of the country and the results of this are described below. central arabia.—in 1917, when on a mission to the emir of nejd, hi. st. j. b. philby crossed the peninsula from sea to sea, a feat previously accomplished by only one other furopean— capt. sadlier, in 1819—his line being from ‘oqair (‘ojair) on the persian gulf to jidda, by way of hnufuf, riyadh and taif. he attributes the exceptional fertility of the hufuf group of oases to the re-appearance at the surface there of the rainfall of a very large area, beyond riyadh, philby was the first european to follow, for most of the way, the great central pilgrim route to mecca. he passed ghat (hat, a centre of the wahhabist revival. after 80 m. of limestone desert alternating with belts of dahana, his route lay across the highlands of nejd, a granitic tract 150 m. in breadth, where he found altitudes up to 3,100 ft.; this tract forms part of the great divide between tlie northeast and southeast slopes of arabia in which, in about lat. 233° n. and long. 433° e. lie the head-waters of w. sahaba. for noless than 200 m. between the small settlement of qusuriya, long. 44° 30’ e. and khurma, lat. 22° n., long. 42° e, —a village of mud huts on the confines of the hwejaz and a point of conflict between the king of the [lejazand the emir of nejd—he found no settled habitation, but encountered vast herds of gazelle. after crossing the rakba plain he reached taif and, following down the gorge of w. fatima, reached jidda. in a subsequent journey, may—june 1918, philby explored south- ern nejd, going 300 m. southward from riyadh to dam and back. he determined astronomically the positions of a number of places, including riyadh (lat. 24°37’ n. long. 46°41’ e.), abu jifan (lat. 24° 29’ n.), hair (lat. 24° 21’ n.), sulaiyil (lat. 20°25’ n., long. 45° 29’ e. ) and dam (long. 44° 4o’ e.), and ascertained various heights by aneroid readings. as a result of the journey, the hydrog- raphy of the tuwaiq plateau, the backbone of central arabia, is now as well known asany part before the world war. philby’s estimate of the population of riyadh is 12-15,000, and its most conspicuous buildings are the palace of the emir and the great wahhabi mosque. the oases of nejd were found to comprise, usually, a nucicus town with scattercd hamlets, with not more than a few square miles of cultivated land around in each case, and populations never exceeding 10,000. in aflaj and kharj he made a notable discovery of ruin fields of considerable area, which suggest burial mounds of an early era. in both districts, the peculiar system of irrigation from natural reservoirs or decp well pits by means of subterranean channels, or kures, was unexpectedly found to prevail. at umm al jabal, just south of laila, is a lake 3 m. by 1 m., possibly the largest sheet of permanent water in arabia, and also a number of reservoirs of un- usual size, one measuring 500 by 600 yards. in the makran depres- sion, south of badia (lat. 22° n.),are other perennial pools of water surrounded by woods of well-grown trees. the oasis of dam locally known as ‘‘ the wadi,” consists of some 20 separate settle- ments with a total population of 9,000, mostly of negro origin or of the dawasir tribe. it was found that the nejd oases are not tropical paradises; that there is no chain of oases linking nejd with cither ‘asir or yemen; and that there is no region of fertility between southern nejd and oman, nor any settled spot between it and either oman or hadhramaut. northern arabia.—as a result of two journeys in arabia in i910 and 1912 lt.-col. g. e. leachman drew attention to w. khar, an important affluent of the euphrates, and discovered its possibilities as a line of communication between syria and ‘iraq via the oasis of jauf, noting that water is obtainable at regular intervals along it. ile was first among europeans to visit the wells at leina, of which there are several hundreds, spread over an area of 5-6 sq. m.; and he is the only european who has made any record of a journey from j. shammar to suq‘ash shuyukh. his travels were cqually important politically, for he laid the foundations of a good understanding be- tween britain and the emir of nejd; he was treacherously shot, aug. 1920, in mesopotamia. in 1913-4, miss gertrude bell travelled alone, except for native yuides, from damascus to the neighbourhood of vaima. yhence she passed eastwards over new ground along the southern margin of the nafud to j. shammar and visited hail; then northwards by loqa to najaf and baghdad, adding considerably to knowledge of a region hitherto traversed only by wallin in 1848. miss bell was at that time the only woman traveller in arabia, with the exception of lady anne blunt, and one of the few women who can lay just claim to the title ‘‘ explorer,” for she surveyed her route by prismatic com- pass from start to finish. arabia capt. shakespear, british political agent at kuwait, who became political officer in nejd in 1914, and was killed in action in i915, crossed the peninsula in 1913-4 from kuwait to suez by way of riyadh, buraida, haiyaniya and jauf al ‘amir, following an entirely new course beyond the last-named place. other expeditions—by douglas carruthers in 1909, by alois musil in 1908-9 and igio and by barclay raunkiaer in 1912,—yielded valuable results. the hejaz—vhe arabian section of the iejaz railway was so ill- known before the world war that even the stations could not be enumerated correctly. determination, in 1917, of the lat. and long. of ma‘an and the observation of the long. of a few stations to the sauth enabled valuable adjustments to be made in the trace of the line. a belt of the hejaz slope, some 300 m. in length between wejh and rabigh and a smaller tract immediately south of “aqaba were explored as a result of war operations, and a turkish statf map of the country within a 30-m, radius of medina added further useful data, so that a great part of the hejaz can now be mapped with fair accuracy. the billi tribe who people the rolling country between wejh and the railway were found to be pure nomads without a single settlement in their district except one small garden at al kurr; the juheina and harb to the south of them are less nomaclic. ‘asiry and yemen.—toward the end of 1918, in the course of idrisi’s final campaign against the turks, british officers met tribes- men from the least known parts of the interior, and gained much topographical, social and political knowledge, especially on the com- position and distribution of the chief tribes of ‘asir and yemen. the position of ibha (formerly menadhir), the headquarters of the turks, was ascertained, though no european got there even when they surrendered. sabia, ldrisi’s capital, about 23 m. east-south- east of jizan, was visited by an indian medical officer. in yemen, in 1909, a considerable amount of survey work was done by m. a. beneyton, a french engineer, for a proposed railway from hodeida to san‘a and ‘amran and much unexplored territory was mapped on a scale of 1:250,000. g. wyman bury went from hodeida to sa‘na in 1912 and has thrown light on the topography and economic conditions of yemen. a. j. wavell visited san‘a in 19t1 and gave the best description of the city since manzoni, 1884. he found the population reduced to 18,000 as compared with ijarris’ computation of 50,000 in 1891. the decline in population and the commercial de- pression prevalent in yemen may be attributed largely to the law- lessness of the intractable zaranik and qahtan tribes who occupy the country between the highlands and hodcida. . aden protectorate and hadhramaut.—bury, in 1911, described his penetration of the kaur watershed (alt. 7-9,000 ft.), north of the yafa‘l fadhli country. he visited yeshbum (population 4,000), the capital of the upper ‘aulaqi, situated in a plain producing cotton and indigo and carrying on an industry in cotton fabrics, and got as far a beihan, r10 m. inland of shughra and almost in touch with marib. the red sea coast.—the naval patrol during the world war ex- plored the intricate coastline from ‘aqba to aden. the triple coral reef fringing it had kept this coast almost inviolate, but the very numerous openings through the reefs are now known and have been charted. ‘fhe desert north of lat. 30° n. may be considered as well known, thanks largely to the activities of the royal air force, which has maintained a regular fortnightly mail across it from cairo to baghdad, and to the enterprise of the british nairn motor transport co. (beirut to baghdad via damascus) and of a syrian motor company (damascus to baghdad eva palmyra). various schemes have also been under consideration to connect baghdad with haifa by a trans- desert railway and preliminary surveys have been made in this con- nection, notably by maj. a. l. holt of the ‘iraq railways. south of latitude 30° there has been little exploration since 1921, but a notable exception is an expedition made in the winter of 1923-4 by maj. r. e, cheesman to the hitherto unvisited oasis of jabrin on the fringe of the-great south desert. a british commercial syndicate has also been engaged in prospecting for oil in the province of hasa, and similar work was begun in oman late in 1925. a notable addition to the maps of arabia is sheet no. 32, persian gulf (scale 1:4,000,000) published by the war office in 1924 and including the whole peninsula above latitude 20 degrees. this shect is based on all the latest available information and is certainly the best map ever published of arabia. the million-scale map of arabia now covers the whole peninsula north of lat. 24° n. and a shcet (laila), issued in 1923, covers the central area south of that line down to lat. 20° north. million-scale maps, issued by the survey of india, cover the southwest, south and eastern extremities of arabia but have not been brought up to date. (h. w. m.) il. political history the political situation in arabia has undergone a remarkable change since 1911. at that time the ottoman govt. was able to maintain authority over the red sea provinces of hejaz, ‘asir. yemen and the persian gulf province of hasa. in central arabia supremacy was divided between the emirates of jabai shammar and nejd; while the principalities of kuwait, bahrein, arabia qatar, trucial oman and muscat, the territories of hadhramaut and the aden hinterland were in varying degrees under eifective british protection. in ror2 amir ‘abdul ‘aziz ibn sa‘tud—who, as a youth of 20, had in 1900 rescued the territories of his ancestors from the rule of the ibn rashid dynasty of hail and had since then effectively established his own rule throughout nejd from qusaiba in the north to wadi dawasir in the south—planted at artawiya, a desert watering east of zilfi, the first of the many ikhwan col- onies which have since formed the very basis of his power. (see wautst movement.) by doing so he formally revived in its most puritanical and fanatical form the long-dormant wahibi movement, which had a century before made one of his ancestors for a short time undisputed master of all arabia. his plan was to make the centrifugal elements of nomad society serve his own political ambitions under the banner of a great religious revival, for the furtherance of which he established these col- onics—their number is reputed now to be about 50—as depots or rallying points for the bedouin. he provided the funds neces- sary for the building of mosques therein and arms and ammuni- tion for the use of each colony, which thus formed a contingent of what was in effect a conscript army. for five years the essen- tial character and immense possibilitics of this movement were not appreciated outside the limits of nejd itself. during the winter of 1913-4 ibn sa‘ud suddenly descended upon the hasa province with quite a small force. the citadel of hufuf was captured by a night attack almost without resist- ‘ance on the part of the turkish garrison, which took refuge in the fort-like precincts of the ibrahim pasha mosque, but surrendered almost immediately. the turkish troops were escorted to the coast and with the garrisons of qatif and ‘oqair, which also surrendered, were allowed to depart in peace by sea. . the world war—before the turks had had time to avenge this blow, they were involved in the world war, as the result of which they lost the whole of their arabian empire. early in the war, captain w. h. i. shakespear of the indian political service was appointed british representative at the court of ibn sa‘ud, and the latter immediately began hostilities against jabal shammar, whose ruler sa‘ud ibn rashid, who had suc- ceeded to the emirate in 1908, stood by the turks to the end. captain shakespear was unfortunately killed in the first and only battle of the campaign at jarrab in jan. 1915 and, the battle having proved indecisive, ibn sa‘ud became inactive till the summer of 1918, when he again advanced against ibn rashid but had gained no substantial success before the end of the world war. the only event of importance aficcting nejd during this period was the signing of a treaty of friendship between great britain and ibn sa‘ud in dec. 1916. meanwhile the centre of arabian gravity shifted to the hejaz, where husain ibn ‘ali, emir of mecca, raised the standard of revolt against the turks. ihlusain’s assumption of the title of ‘“ king of the arab countries ” was not viewed with favour by ibn sa‘ud and created between the two rulers an ever-growing coolness, which was prevented from breaking out in open hos- tilities only by the constant efforts of the british government. at the end of 1917 a further cause of estrangement arose out ol a dispute over the oasis of khurma on the hejaz-nejd border. the people of the oasis, being of the wahibi persuasion, and their chief, sharif khalid ibn luwai, declared for and demanded protection of ibn sa‘ud. the latter accepted their allegiance, and a serious crisis arose in the summer of 1918, when king iiusain made two vigorous but unsuccessful efforts to capture the “rebel” oasis. his failure made it unnecessary for ibn sa‘ud to take action and at the end of the war khurma still formed part of nejd. wer with ibn sa‘ud—king husain, unwilling to accept such a situation, appealed for british intervention and in march rogro, a committee presided over by lord curzon decided in his favour. he was authorised to occupy the oasis, and ibn sa‘ud was warned to relinquish it on pain of incurring the displeasure of the british govt. and of losing his subsidy of {60,000 a year. the iejaz 153 forces under the king’s second son ‘abdullah, advanced to turaba, 80 m. from khurma in may, and ibn sa‘ud, disregard- ing the british govt.’s warning, sent a force to meet him. in the dead of night the wahibis surprised ‘abdullah's sleeping camp, and annihilated the whole of his army, some 4,000 strong. ‘abdullah and a small following escaped, and the town of taif was evacuated by its inhabitants in fear of a wahibi advance. even mecca and jidda were thrown into a state of consterna- tion. but ibn sa‘ud, content with the capture of turaba, with- drew to riyadh. his first objective was naturally the emirate of jabal shammar but, apart from occasional raids, he was unable during rot9o and 1920 to gain any substantial success. meanwhile he sent an expedition against ‘asir, the mountainous country south of hejaz, and captured its capital, ibha, in the summer of 1920. ilaving consolidated his position there and among the neighbouring tribes down to wadi bisha, he again turned to hail where an accident now favoured him, sa‘ud ibn rashid being shot dead by a relative during a picnic. the vacant emirate passed to ‘abdullah ibn mit‘ab, who was unable to cope with the heavy task thus thrust upon him and, fearing treachery, took refuge with ibn sa‘ud during the summer of 1921. muhammed ibn talal, his successor, fared no better and in aug. 1921 hail surrendered to ibn sa‘ud. in july ro22, the wahibis occupied jauf, which had long owed allegiance alternately to ibn rashid and to the ruwalla chief, nuri ibn sha‘lan, and extended their activities up wadi sirhan. they even raided transjordan in aug., but were driven back by the royal air force detachment at ‘amman. about the same time they occupied khaibar and taima on the hejaz border and the red sea (hejaz) port of qunfida. by the summer of 1923 ibn sa‘ud seemed to have reached the zenith of his power, and in nov. the british govt. invited him and the various sharifian states (hejaz, ‘iraq and transjordan) to a conference at kuwait, which dragged on till april 1924 without result. meanwhile the ikhwan (particularly during the winter of 1923-4) had carried out a number of raids on the tribes of the ‘iraq frontier, and the failure of the kuwait con- ference resulted in a second raid (in aug. 1924) on several] vil- lages near ‘amman. this was repulsed by the royal air force, but resulted in the extension of wahibi influence to the “ salt villages ’’ of wadi sirhan. the wahibi monarch (who had been recognised by great britain in 1921 as sultan of nejd, and had ceased to enjoy a british subsidy as from march 1924) now played his trump card with results which far exceeded his expec- tations. a wahibi army launched against hejaz captured taif without opposition in sept. ro24, and, owing to the absence of its commander, committed excesses which were immediately disowned by ibn sa‘ud. after a battle at hadda in the taif mountains, mecca was occupied in oct. and by the end of 1925 the whole of the i[ejaz was in ibn sa‘ud’s possession. iii. divisions of arabia oman.—this roughly comprises the extensive and mountain- ous promontory which forms the eastern extremity of arabia, extending from ras musandam on the gulf of oman to the eastern limits of hladhramaut at ras sajar (lat. 16° 8’ n.) on the indian ocean. its capital, muscat (see 20.99 and 19.43), was before the war an important centre of the traffic in arms, which was in 1912 subjected to control by the establishment of a warehouse at the instance of the british government. the present sultan of muscat, saiyid taimur, who succeeded his father, saiyid faisal ibn turki, in 1913, enjoys a nominal author- ity over the whole of oman, but his rule is effective only on the coast. the tribes of the interior are practically independent under the loose control of an imam of the ‘ibadi sect, whose centre is at rustaq. a rising of the ‘ibadis in 1913-4 against the sultan resulted in the occupation of bait al falj near muscat by a british indian force, which remained there throughout the war, defeat- ing the rebels in 1915. since the war the sultan’s administration has given rise to much dissatisfaction and in 1920-1 the british govt. intervened to patch up an understanding between him and 154 the ‘ibadi imam. shortly afterwards the sultan had to agree to the creation of a sort of council of regency for the adminis- tration of the state and since then he has taken no active part in the government of his dominions, residing partly in india and partly on his personal estates. for all practical purposes the administration is controlled by the government of india. kuwait (see 15.956).—of the various states along the arabian coast of the persian gulf, kuwait alone has had its frontier with nejd defined. its chief, mubarak ibn subah, always a staunch friend of great britain, died in 1916, and was succeeded by his son, jabir, who died the following year, to be succeeded by his brother, salim, an inveterate foe of ibn sa‘ud. salim died in 1921 and was succeeded by jabir’s son, ahmad, who still rules. the importance of kuwait lay in the fact that before the war it was the chief entrepet of central arabian trade, but recently owing to a dispute regarding the sheikh’s right to col- lect customs dues on goods in transit, ibn sa‘ud has developed the three hasa ports of jubail, qatif and ‘oqair and deflected trade in that direction. kuwait trade has consequently to some extent cleclined. . oatar.—the small peninsular state of qatar has since 1914, when it ceased to be under turkish rule, maintained a sort of independence under its sheikh, ‘abdullah ibn thani, whose authority does not extend beyond a few settlements on the coast and who is on good terms with his powerful neighbour, the wahhabi sultan. trucial oman.—between qatarand oman proper he the petty states of abu thabi, dibai, sharja, ‘ajman and umm al qaiwan, each under its own semi-independent sheikh and all controlled and protected by great britain, whose representative resides at sharja, in virtue of an agreement made in 1892. the authority of these states is confined to the sea-coast and their boundaries with nejd have not been defined. hadhramaut.—this comprises a considerable and prosperous territory marching with oman on the east and the aden pro- tectorate on the west. its boundaries northward towards the great desert are undefined. the greater part of this territory is ruled by sultan ghalib ibn ‘awadh of the qa‘aiti dynasty, which is closely linked with the indian state of haidarabad. his capital is at makalla on the coast and the actual work of admin- istration is carried on in the sultan’s name by a wazir, saivyid husain tbn mihdar. apart from makalla, shihr on the coast and shibam inland are the main centres of the qa‘aiti allegiance, while tarim and saiyun (both inland) are the headquarters of two co-equal sultans of kathiri stock, whose affinities are with java and the east indies. these sultans are mansur and muhsin, both sons of ghalib ibn ahmad, and the effective gov- ernment of their dependencies is in the hands of a wazir, salim ibn ‘abud. during the war the qa‘aiti influence was exercised on the side of great britain, while the kathiris were intensely anti-british and were suspected of supplying the turks in yemen with goods imported via shihr and shibam. the qa‘aiti-kathiri feud was temporarily composed in 1918 by a treaty, but the prosperity of the hadhramaut and the develop- ment of its great agricultural resources—it is an important to- bacco-growing centre—can only be secured by the elimination of the kathiri element whose rule is as oppressive as that of the qa‘aiti dynasty is mild. the whole area falls within the sphere of british influence and protection. yemen and ‘asir.—these form geographically a single unit extending northward between the red sea and the western (undefined) border of the great desert from the frontier of the aden protectorate to a line running northeast from hali point to wadi bisha. before the war this area formed the turkish provinces of yemen (south) and ‘asir (north), and during the war they were held to the end by turkish troops whose hold on ‘asir was always somewhat precarious. here the authority of ‘turkey had since 1910 been disputed by satyid muhammed at idrisi, who maintained his independence in the coastal low- lands (tihama) with his capital at sabia and in the ports of maidi and jizan. a turkish expedition against him proved inellective, and with italian assistance in 1911-2 he consolidated arabia his position. in 1915 he entered into an agreement with the british resident at aden, but was unable to assist the allied cause in any substantial manner. after the armistice he con- tinued hostile to the imam of yemen, and cultivated friendly relations with king husain. in 1921 he occupied hodeida, rely- ing on his treaty with great britain. meanwhile in 1920 ibn sa‘ud had occupied the uplands of ‘asir and their chief town, ibha, and in 1922 the idrisi himself died. his son and successor saiyid “ali, maintained his position somewhat precariously till 1925 when the imam yahya of yemen occupied hodeida. since then the idrisi, confined to sabia and the ports of jizan and maidi, has practically ceased to count as an arabian potentate. the imam yahya ibn muhammad, religious head of the zaidi sect and temporal ruler of the yemen, has on the other hand greatly consolidated his position. coming into power in 1904 he was soon involved in a serious rising against the turks which was with difficulty subdued in 1905 (see 2.270). an ar- rangement was then arrived at, but was broken in 1910, when the imam besieged san‘a. the city was relieved, and in 1913, by an imperial farman, a mediatised status was conferred on the yemen, the imam being recognised as the religious and social chief of the zaidielements. at the outbreak of the world war he declined to negotiate with aden, and sided with the turks, using his influence to stir up strife against the british among the tribes of the hadhramaut and the aden protectorate. the turks left the yemen at the end of 1918 and a british garrison occupied hodeida. in aug. 1919 a british mission under col. tl. f. jacob proceeded inland from hodeida to visit the imam, but was captured by quhra tribesmen and detained at bajil till december. in the early part of t921 the imam’s troops, com- manded by the former turkish wali, mahmud nachim pasha, became active in the tihama around hodeida but were antici- pated by the idrisi who occupied that port in february. since then the imam has from time to time threatened and actually violated the aden protectorate frontier and eventually ejected the idrisi from hodeida (see above). at the end of 1925 he was in a stronger position than ever before, and ranked second only to ibn sa‘ud among the rulers of arabia. the world war seriously affected the prosperity of hlodeida and other yemen ports, but during 1925 italian commercial enterprise seemed to be actively engaged in restoring their pre-war importance, while late in the same year a british mission set out to visit the imam. iv. trade and communications communications.—at the beginning of 1926 the hejaz line from ma‘an to medina was the only railway within arabian territory. motor transport was still in a backward stage—a few cars have used the jidda-mecca, rabigh-mecca and ‘ ogair- hufuf route for some years past—but there is likely soon to be a great expansion in this direction. there are no made roads except the one from hodeida to san‘a but, except in the moun- tainous and drift-sand regions, communications are easy by camel and the tracks are generally possible for motor traffic. the hejaz has a telegraph line from mecca to jidda which is connected by cable with port sudan. the hejaz has also some nine wireless stations and there are similar installations at ibha hodeida and san‘a. both the red sca and persian gulf ports and makalla have adequate regular steamer services. gen- erally speaking the last few years have witnessed a considerable improvement in communications and the near future should sce this improvement greatly extended. imports.—arabia is essentially an importing country and imports piece-goods and foodstuffs (rice, flour, sugar, tea and spices), which it pays for by a considerable sale of camels (to egypt, syria, etc.), by a modest export of hides, dates, cofice, pearls, etc., and by supplies of all kinds to the annual pilgrims to the hejaz (averaging 100,000). the chief ports are jidda, hodeida, yenbo', wejh, rabigh and mocha on the red sea, makalla and shihr on the indian ocean, and muscat, bahrein, ‘oqair, qatif, jubail and kuwait on the persian gulf. customs duty at jidda is said to amount to £500,000 (at a general rate of arabic literature—arbitration, industrial 10% with exceptions in the case of silk, tobacco, etc.) in an ordinary year, but it is impossible to give an estimate of the total value of the export and import trade of all arabia. production.—camel-, sheep- and horse-breeding are carried on on a considerable scale by the bedouin but the market for arab horses is no longer what it was before the war, while the conditions of modern civilisation have made horses a luxury for the rich rather than a necessity for all. ‘the persian gulf has a flourishing pearling industry, and in the red sea pearls are found in small quantities and there is a flourishing trade in black-coral (made into rosaries for pilgrims). the fishing (and salting of fish) industry has a great future but needs proper organisation. at salif and other places there is good rock salt, while the west coast of arabia is suspected, but not proved, to be rich in minerals. in the hasa abas (cloaks) of good quality are made and in the yemen there is a small industry of decora- tive gold and silver work (scabbards, sheaths, etc.). (see hejaz.) brbliography.—alois musil, nord arabien (1909), and zur zeitgeschichie von arabien (1918); wyman bury, the land of uz (1911) and araeta infelix (1915); a. j. b. wavell, a afodern pil- grim in mecca (1918); c. snouck hurgronje, the revolt in arabia (1917), the holy war ‘‘ made in germany” (1915) and nederland en de islam (1915); barclay raunkiaer, gennem wahhabiternes land paa kamelryg (issued in an english translation by the arab bureau at cairo in 1916); d. g. hogarth, arabia (1922); c. doughty, travels in arabia deserta (new edition with introduction by t. e, lawrence, 1921); h. st. j. b. philby, the heart of arabia (1922): h. f, jacob, aings of arabia (1923); official handbook of arabia (2 vol.) i.d. 1128 (1917). mention should also be made of countess malmignati’s through faner deserts te afedina (1925) and of lowell thomas with lawrence tn <lrabia (1925). papers on various parts of arabia are to be found passim in the journal of the royal geograph- ical society. (fy six j. bare) arabic literature (sce 2.271).—a vast number of writ- ings have appeared since rogr1o in various parts of the east— e.g., egypt, north africa, india. among recent publications, a book written by sheikh ali abdel razck of cairo on islam and the bases of government (1925) is particularly noteworthy for its political and cultural significance. the author, who has been punished for heretical teaching by deprivation of his judgeship, as well as his professorship in el-azhar university, cairo, seeks to prove that in the koran and in the traditions ( hudith) about mahomet there is nothing to indicate that the prophet cherished ambitions of earthly kingship, or that he proclaimed anything concerning matters other than those affect- ing faith and practice. it would follow from this that there is nothing to prevent mahommedans from learning from unbe- lievers, or from keeping pace with modern european progress. great progress has been made in the work of editing and translating classical or standard arabic texts. rhuvon guest has edited and published (1912) the arabic text of the work on the governors and judges of egypt by f1 kindi (897-961 a.d.; 283-350 a.l.). c. h. h. macartney has done the same (1910) for the diwden of ghailin ibn ‘ugbah, known as dhw’r- rummah., verses by dhuw’r-rummah are quoted frequently in the works of lexicographers, but before the publication of the diwan only one of his longer poems had been made easily accessible. d.s. margoliouth has made available, by publishing the text with a translation, a work which has been pronounced to be the best on life in the palaces of the caliphs and generally one of the most instructive in the arabic language, the expe- riences of nations (tajarib al-uman) by ahmad ben mohammed miskawaihi! (d. 1030 a.d.; 2330-421 a.ll.). a continuation of the &xperiences of nations was written by abu shuja ‘rudhra- wari (d. 1095 a.d.; 488 a.r.). it appears to be in the main an abridgment of the chronicle of hilal ben muhassin ben ibrahim (359-448 a.u.). this text also has been published, with a translation, by margoliouth.? chemistry came to europe by way of the moslems of spain; but of the vast chemical literature in arabic very little has been made accessible to european students. some importance attaches, therefore, to the publication, from three manuscripts, 'the eclipse of the ‘abbasid caliphate, original chronicles of the fourth islamic century (1920-1). ? included in the work mentioned above. 155 of the text, with a translation, of the book of knowledge acquired concerning the cultivation of gold by abu'l-qasim muhammad ibn ahmad al-‘traqi, who seems to have flourished in the 13th century a.d. (7th century a.u.).3 in ro2r sir charles j. lyall published a complete text, with translation, of the afufadduliyal,t the famous anthology put together by al-mufaddal, who was head of the school of al- kifah. al-kifah and al-basrah had become the headquarters of schools of grammatical and linguistic research which drew upon the national stores of poetry preserved in the memory of the tribal traditionists or rawis. lyall holds that the anthology is a collection of genuine pre-islamic poems. d. s. margoliouth, on the other hand, maintains that the ostensibly pre-islamic poetry is suspect on both external and internal grounds.° in ro14 dr. alphonse mingana published some leaves from three ancient korfins.© the manuscript from which these leaves were taken is a palimpsest, the upper script being a series of closely written homilies in arabic by early christian fathers, such as theodosius, chrysostom, and mar jacob. the tradi- tional view is that the text of the korin, as it now stands, was fixed by command of the caliph ‘othman; but these leaves seem to belong. to a time before the text was fixed. that the traditional view may not be correct is suggested by the con- tents of a manuscript brought from the east by dr. mingana and published in 1925.7 the manuscript incorporates a discourse (chap. 25-30) which consists entirely of quotations of the koran translated into syriac. these quotations seem often to represent a version which is not always in harmony with the textus recepius of the koran, but exhibits whole verses which are not found in it at all. there are grounds for thinking that the version made its appearance some time between 684 and 704 a.d. this supports a suggestion made by mingana in 1016, that the text of the koran was standardised, not under the caliph ‘othman, but under the much later umayyad caliph ‘abd al-malik b. marwan.’ in 1922 a. mingana published a translation of the book of religion and empire, a semi-offhicial defence and exposition of islam written by order at the court and with the assistance of the caliph mutawakkil (847-61 a.p.), by ‘ali tabari, who seems to have died about 854 a.p. this is the first work by ‘ali tabari to be published. more recently mingana has published a charter granted by the early caliph muktafi iti. (1136-60 a.d.) to the nestorian patriarch, abdisho iii. (1138-47 a.d.). this charter has survived only as a model of good arabic composition in an arabic anthology. it is written in rhymed prose and in a very florid style. it shows that the early caliphs treated their subjects with great toleration. bibliography.—in addition to the works mentioned in the body of the article, see m. hf. shayk, ‘abd al-raziq, ‘arabic literature since the beginning of the nineteenth century,” bulletin of the school of oriental studies, london institution. vol. li., pt. 2 (1922) and pt. 4 (1923). (m. a.c.) arabi pasha (c. 1839-1011), egyptian soldier and revolu- tionary leader (see 2.283), died at cairo sept. 21 1911. arber, edward (1836-1912), british man of letters (see 2.323}, was killed in a taxicab accident in london nov. 23 1912. arbitration, industrial: sce industrial relations. 3 the arabic text edited with a translation and introduction by fe. j. holmyard, m.a. (1923). 4 the mufaddaliyat. aa anthology of ancient arabian odes com- piled by al-mufaddal, son of muhammad, according to the recension and with the commentary of abg@ muhammad al-qasim ibn mu- hammad al-anbari. edited for the first time by sir chas. james lyall. two volumes (1921), volume 3 (1924). the dates of mufaddal'’s birth and death are uncertain. the years mentioned for his death vary from 164 to 168 and 17o. 5“ the origins of arabic poetry ” in the journal of the royal a static soctety (july 1925), pp. 417-49. 6 leaves from three ancient qurdns, possibly pre-‘othmanic, edited by alphonse mingana and agnes smith lewis (1914). 7tan ancient syriac translation of the kur'dn exhibiting new verses and vartunts (1925). 8 journal of the manchester neyptian and oriental society (1916), see further hastings encyclopaedia of reliaion and ethics (1918). 156