and N. shores are formed by the desert country of southern Persia, and are similarly very sparsely populated, Bushire, in the N.E. part of the Gulf, the port for the Shiraz district of southern Persia, and Bandar 'Abbas, at the entrance of the Gulf, being the
chief centres of population. The hot season of the year is from May to October, July and August being the hottest months. The Persian Gulf has an unenviable reputation for its dangers from heat-stroke, and the sun's rays seem to have a peculiar deadly power in this region, for the risk of exposure is greater than in any
part of the world, though other countries have a temperature which
is equally high. The explanation is to be found in the extreme
flatness of the country and the absence of trees or vegetation.
The clear atmosphere is in its upper strata free from clouds and
dust, so that the sun's rays undergo scarcely 'any absorption and
strike down with full force on the light-brown desert soil, from
which they are radiated and reflected to a great extent. The
relative humidity of the air along the shores of the Gulf is high,
so that exposure to the direct and reflected rays of the sun and
radiation from the hot soil are encountered in a moist atmosphere.
So trying is the heat that some parts of the Persian Gulf are almost uninhabitable to natives in the hotter months. The greatest care requires to be taken by white races to avoid exposure to the sun and heat. Dwellings require careful construc- tion, with thick walls and roofs of non-conducting material to keep out the heat-rays, and fans and punkahs are essential for the promotion of currents of air in the inhabited rooms. Per- sonal protection, in the shape of thick pith topees, or cork helmets, and spinal pads, is necessary in the hot months, the clothing being light and loose and not too thin. Fatigue from physical ex- ertion is a predisposing cause of heat-stroke, and constipation and alcoholic indulgence should be avoided.
Should a person be infected with latent malaria, heat exposure is very likely to induce an acute malarial attack and the combination is almost certain to lead to hyperpyrexia. On this account malarial subjects living in the Persian Gulf should take especial care to have an effective course of treatment in order to eradicate the disease as far as possible. The frequent association of heat-stroke with malaria is to be borne in mind in the treatment of heat hyperpyrexia, for, should the temperature of the patient not subside rapidly after treatment with cold sponging in a current of air or cold baths and ice, an intramuscular or intravenous injection of 10 grains of quinine bihydrochloride should be given without delay. In the case of white people exposure to heat of itself frequently causes heat-stroke, but probably in almost all cases of heat hyperpyrexia amongst natives the malarial complication is the exciting cause and therefore with them quinine treatment is all-important. Natives are generally immune to thr effects of heat apart from other complicating causes of high temperature, such as malaria, etc., whereas white races may be affected with heat-stroke from heat exposure even if in perfect health. If a white person suffers in the hot months from any disease causing fever, e.g. enteric or sand-fly fever, etc., there is always a serious danger of hyperpyrexia, and this has to be guarded against.
The Effects of Heat. The effects of exposure in the case of white races are not only manifested by the acute attack of heat-stroke, but, if this is avoided by proper care, it is nevertheless certain that long residence in the Persian Gulf causes a certain amount of tissue degeneration, owing to the exposure of the body cells to abnormal conditions of temperature. The highly specialized cells, viz. those of the nervous system, suffer most ; and nerve-cell fatigue is shown by manifestations of neurasthenia. I^ack of the power of brain con- centration and severe inability to undergo the mental strain of arduous work are often the penalty which white races pay.
Beri-beri is a dietetic deficiency disease which manifests itself by cardiac weakness with shortness of breath, swelling of the legs and peripheral neuritis with numbness of the limbs and weakness. The climatic conditions of the Persian Gulf particularly seem to predis- pose to this disease, for it very frequently attacks white persons resident there, especially if they are exposed to dietetic hardships.
Residents in the towns along the Persian Gulf are exposed to the same dangers from disease as are experienced in similar places in Mesopotamia and Persia (see MESOPOTAMIA and PERSIA). Thus malaria and sand-fly fever, dysentery, typhoid and paratyphoid fever, cholera, smallpox, and occasionally typhus fever, eye diseases, oriental sores and indeed any disease conveyed by impure water, flies, contaminated dust or the contagion of sufferers from infectious diseases, are prevalent in the inhabited places along the Persian Gulf, and precautions must always be taken to guard against them.
(W. H. VV.)
Geology. Large portions of the littoral had not up to 1921 been examined geologically. Of the numerous islands that dot the Gulf many are partly at least of volcanic origin, notably Qishm and Ormuz.
The geological formations represented are the following in descend- ing order:
Recent or sub-recent Shelly conglomerates and dead coral
reefs of the littoral; red sandhills of the coast of Trucial Oman; alluvium of Turkish Iraq; river and lake deposits of Oman and the interior of Persia.
Pleistocene Foraminiferal oolite or " Miliolite."
Pliocene Bakhtiari scries; grits and conglomer-
ates.
Miocene. Pars series; marls, clays and sand-
stones with limestones and inter- bedded strata of rock gypsum.
Lower Miocene Clypeaster beds of the Bakhtiari
mountains.
Oligocene and Eocene Nummulitic limestones of Persia;
Muscat series; and Bahrein series.
Upper Cretaceous or Ormuz series; lavas and tuffs with
Lower Eocene interbedded clavs and sandstones.
Upper Cretaceous
Jurassic or Lower Cretaceous
Carboniferous to Trias A rchaean
Hippuritic limestones of Persia and
Oman. Serpentinous and other igneous rocks
of Oman.
Oman series ; limestones and slates with
beds of chert. Hatat beds; schists and quartzites.
The latest movement to which the Gulf has been or is now being subjected is one of gradual elevation, of which traces are found in recent littoral concretes, now as much as 450 ft. above present level, and in the flat ledge which surrounds Muscat harbour.
Numerous " shows " of petroleum exist along a broad belt run- ning N.W. and S.E. through Mesopotamia and down the Persian Gulf. These are the most abundant at the foot of a chain of hills where the oil wells of Daliki, Bebehan, Ramuz and Shushtar, Diz- ful, Pusht-i-Kuh, and Qasr-i-Shirin are situated. Oil has, however, been struck in paying quantities hitherto only at a point 30 m. E. of Shushtar. Experimental boring on Qishm I. in 1916 had not given any result up to 1921.
Among othef mineral products, asphalt is found at Bahrein ; coal 30 m. inland from Sur, and some seams of good coal in newer strata; sulphur occurs in a fairly pure state at Khamir and Bustaneh near Lingeh, and on Qishm I.; copper, as copper glance and malachite, occurs in the interior of Oman; copper-mines are said to have been worked in the neighbourhood of the coast near Lingeh by the Portuguese, but all trace of them has been lost. Red ochre, for which there is only a limited market, is mined on Ormuz, Abu Musa and other islands in the Gulf; salt, as deposits, on Ormuz and Qishm I., and by evaporation, near Mohammerah, Kao and else- where on both sides of the Gulf; gypsum is widely distributed throughout the Gulf; iron, as haematite and pyrites, widely found through the Ormuz series.
Earthquakes are frequent and sometimes severe in the Persian Gulf proper, especially on Qishm I. and on the coast in the neigh- bourhood. In 1865 an earthquake levelled the villages of Darveh Asul near Mugam; in 1880 an earthquake caused 120 deaths in Basra; in 1883 severe shocks were felt from Bushire to Tahiri; in 1884 an earthquake caused 132 deaths on Qishm I., which was in consequence deserted ; in 1897 an earthquake destroyed Qishm town and caused over 1,000 deaths; further shocks were experienced at Qishm and Bandar 'Abbas in 1902 and 1905.
Agriculture. Cereals are produced in considerable quantities in the hinterlands of Mohammerah and Bushire and in the intervening coastal strip; the rest of the Gulf largely depends on imports from this part of Persia or from India. Dates are grown for the European market at Muscat and for local consumption on both sides of the Gulf, but not in considerable quantities. The Muscat date reaches maturity sooner than the Basra crop, and is commercially valuable.
Live Stock. ^-Came\s are abundant on the Arabian side of the Persian Gulf littoral and are also found on the Persian coast, espe- cially where the country is open. Horses are scarce in Oman and few are kept in Trucial Oman or in Bahrein or El Hasa. But they are more common in Qatar and Kuwait. Nejd, or Central Arabia, is the principal horse-breeding country adjacent to the Persian Gulf, and is the only one in the world, except the adjacent Syrian desert, where the genuine Arab is produced on any considerable scale.
Sailing Craft. The Persian Gulf is by tradition the home of sailing craft, for their skill in handling which the Phoenicians after- waros became famous in the Mediterranean. There are some 14 types of native craft which belong to the Persian Gulf proper. The same principle of construction applies to nearly all; as a general rule these vessels are remarkable for the beauty of their lines. They sail well and are weatherly craft. The principal shipbuilding centres in the Persian Gulf are now Kuwait, Sur in Oman and Lingeh.
Fisheries. Few seas are more prolific in fish than the Persian Gulf and the Gulf of Oman ; the great proportion of known species are edible and many have a commercial value for the isinglass or oil
