316 PEKSIA compact feldspar with green earth along the beds of the torrents, whose waters also bear evidence of the existence of chalk within the mountains. The branches of the great chain are geologically described as consisting of cal- careous substances on their eastern skirts, schistose rocks on their southern acclivities, clay intermingled with quartz in the middle and higher altitudes, and granite in the lower tracts of their northern aspects. The table land of Azerbijan is essentially volcanic, and traces of volcanic action are visible in various parts of the Elburz range. The peak of Dema- vend is an extinct volcano ; and the frequent earthquakes in the vicinity of the mountains indicate the existence of subterranean fires over a wide-spread region. There are hot sulphur springs at Ask in Mazanderan, S. of Mt. Dema- vend. The Sahund mountains exhibit great masses of calcareous conglomerate resting on a base of granite. Their summits are composed of porphyry, sometimes containing crystals of glossy feldspar and hornblende. Some of the lower hills intervening between these moun- tains and Tabriz are covered with blocks and pebbles of a dark blue rock containing calcare- ous matter. The soil of the Great Salt desert is a stiff clay overlaid with a saline efflorescence, in some places to the depth of an inch. South- ern Persia appears to have undergone a grad- ual elevation, from a period long antecedent to historical times, converting into lakes the streams which formerly flowed to the Persian gulf. The mineral products comprise iron, copper, lead, and antimony among the metals, and salt, sulphur, marble, and coal. Extensive coal fields have been discovered near the city of Casbin on the route between Teheran and the Caspian sea ; there are also mines in the Elburz, N". of the capital, from which coal is brought to the city, where it is sold for $10 to $15 a ton. Bitumen and naphtha are obtain- ed in various parts of the kingdom. The tur- quoise is the principal precious stone produced in the country. The turquoise mines are near the village of Madene, about 32 m. from Nisha- pur in Khorasan, where they have been work- ed for many centuries, and yield remarkably fine specimens. The base of the ridge where they lie is composed of white, gray, yellow, red, and brown porphyritic earth, interspersed with veins of brilliant red, disposed in hil- locks, on the top of which rest beds of lime- stone or porphyritic conglomerates. The mines are opened in beds of porphyritic earth or rock, deeply tinged with iron, through which the turquoise is disseminated in veins, nodules, and irregular masses. They are let out by the government. The modifications of climate in Persia are largely dependent upon the varying elevation of the surface. Comparative warmth throughout the year is characteristic of the low strips along the coast, on the Caspian as well as on the Persian gulf, while the great interior plateau is known to the natives as Sirhud or the cold region. Here the winter lasts from the first or middle of December to the middle of February; the fall of snow is always considerable and sometimes heavy, and severe cold prevails. On the other hand, the heat of summer is intense, so that the climate of the table land is only really en- joyable during the spring and autumn months, which are described by European travellers as truly delightful. At Teheran spring begins in the latter part of March and extends to the middle of May. In July the temperature rises to 97 indoors throughout the day, and all who can do so retire at that season into the cooler regions of the country; they re- turn toward the first of October, when au- tumn begins, continuing two months. The shah spends the summer under canvas on the slopes of the Elburz. In the hot weather the nights are clear, bright, dry, and compara- tively cool, and the people are then in the habit of sleeping on the housetops. Ispahan is one of the healthiest Persian cities for a summer residence. At Shiraz May is the pleasantest month of the year, but after the middle of June the thermometer there commonly indi- cates 100 in the shade, and frequently rises to 110. In the low lands on the Persian gulf the heat of summer is increased by the winds from the sandy deserts with which this region abounds, but the winter and spring are delight- ful. Notwithstanding the great extremes of the climate of Persia, and the sudden transi- tions from heat to cold, it is very healthy, with the exception of the low coasts of the Caspian, where from the superabundance of moisture and of vegetation fevers are prevalent. The annual rainfall is small, and appears to have been decreasing during many centuries. A register kept at the British legation in Teheran in 1867 showed that snow or rain fell there on 49 days in the first six months of that year, but that on 34 of these days the fall was only a few drops or a slight shower. The second half of the year is usually still dryer. Trees are very scarce in the greater part of Persia, but the mountain slopes of the Caspian prov- inces are heavily wooded with valuable timber, Including oak, ash, elm, beech, fir, and walnut. The juniper grows in this region, and the box tree attains a height of from 20 to 30 ft. Olive plantations thrive in the valleys, and in the lowlands the fig, the grape, and the pomegran- ate grow wild, amid mimosas and lofty oaks. The arborescent vegetation of the elevated plains consists mainly of thorny bushes, acacias, the terebinth, the tamarisk, and the jujube. The mountains of the plateau are comparative- ly treeless, though there are forests of oak on the ranges in Laristan; and there are vast tracts where the only trees to be seen are in the neighborhood of villages and along the banks of streams, or in the oases, where the date palm is usually a prominent feature of the landscape. The liquorice plant is found in profusion on the plain of Merdesht and near Shiraz, where the chenar, oak, and cypress are
