Page:1902 Encyclopædia Britannica - Volume 25 - A-AUS.pdf/766

 ASIA

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the existence of almost boundless sources of mineral wealth in the north. Explorations in China have opened up nevy and vast fields for mining industry in the east ; and the plains of India and Burma appear in a new light under the display of economic possibilities which the systematic labours of the Geological Survey of India have revealed. Never perhaps in the world s history has the importance of investigating old fields by the newest lights of science been so fully illustrated as in Asia during the last quarter of the 19th century. Changes in the configuration of the continent, due to slow processes of upheaval and subsidence, proved not only to have taken place in the Physical have been and thereby modified climatic conditions, and to the history of thebe human in the earth s have sensibly ^ ^ j affected tinued action can traced race in the ut t e r con

CrUS

' present, and in one instance at least (in Turkestan) the actual measurement of the progress in upheaval has been found possible. One of the most remarkable discoveries of the last decade of the 19th century is the continuation westwards through Baluchistan to. the Persian border of that line of volcanic activity which, Volcanoes. commencjng in Kamchatka, and following the eastern coast-line of Asia to the Malay archipelago, there turns westward to the Sea of Bengal and is arrested in Arakan. No trace of it is to be found in the line of depression formed by the IndoGangetic alluvial plain across the width of the Indian peninsula, but it is again manifest in the active mud volcanoes of the Makran coast, and continues trending slightly north of west to the Persian frontier, where in (approximate) lat. 28° 30' N. and long. 61' E. it culminates in a giant inland volcano called the Koh-i-Taftan, or “burning” mountain. The highest peak of this mountain is 13,480 feet above sea-level, and from it there issues a perpetual pillar of smoke, which hangs heavily above the snow-clad summit. This volcano (which has been ascended by Captain Sykes) is, so far as is known at present, the only7 inland volcano in Asia. Its position has been well fixed from the Baluchistan survey bases. In India geological science has shaped the historical outline for the evolution of geography from the early ages, when a land conr i i I nexion existed between India and Africa, to the gradual an( s ow rocess bistor'f ^ ^ P °f Himalayan upheaval, and the formImlia^y ° aform ti°n in°f which the Himalayan the we now seevalleys, them. byTheerosion, entire in peninsular area, including the north-west borderlands and Burma, are shown to have been submerged when the greater part of the peninsula (including the Gangetic basin) existed in the form of dry land, and the fascinating theory of a continuous sea which united the basins of the Indus and Ganges has to be given up. Many of the shifting changes which have occurred in the channels of great rivers are matters of history, as are some of the alterations in the coast-line, which can be readily traced on the Makran seaboard and between Bombay and Karachi. Climate.—Although the general nature of those influences which govern the phenomena of climate over the broad area of the Asiatic continent have been fairly well established, yet the improvements ip the methods of meteorological science and the establishment of centres for the record of observed phenomena over a very wide extent of Southern and Western Asia have much improved our knowledge of local cause and effect, and have especially assisted in supplying those data which enable meteorologists to determine the probable course and duration of disturbances, or, in other words, to make “weather forecasts.” Improved means of telegraphic communication have added greatly to the facilities with which such prevision is rendered possible. For instance, the atmospheric conditions prevailing in early summer in the neighbourhood of the Seychelles Islands indicate the probable force and fulness of the monsoon on which the prospects of Indian agriculturists so largely depend ; and much loss of life and property is undoubtedly averted by the comparative facility with which the probable course of hurricanes and cyclones can be foreseen and the necessary precautions signalled. In the field of investigation into climatic influence on the conditions of life, and ultimately of human existence, considerable advance has been made of late years, with results that will be more beneficial than they are at present when the theories which support them become more fully confirmed and recognized. The proposition that malarial fever is directly propagated by a special breed of mosquito is one of the theories which is new to science at present, and can now be said to be fully accepted. It is one of several which emanate from closer research into the intimate relations between atmospheric and biological conditions. Tides.—Collaterally with investigation into the movements of great air-currents special study has been directed to tidal phenomena along the coasts of Western Asia. Tidal stations have been established on the coasts of India, at Aden and Suez, where a graphic form of registration supplies those data from which tidal elements can be calculated and curves representing momentary variation in the height of sea-level during any period can be constructed.

In connexion ■with these tidal observations extensive levelling operations in India have been carried out to ascertain whether there is any appreciable difference in mean sea-level at various points. The immediate practical benefit of these tidal determinations to the science of navigation is obvious. One of the ultimate results of them will be to supply a more assured basis than exists at present for the determination of altitudes over the land surface of Southern Asia. Recent Investigations.—The first great result of recent geographical research has been to modify pre-existing ideas of the orography of the vast central region represented by Tibet and Mongolia. The great highland plateau which stretches from the Himalaya northwards to Chinese Turkestan, and from the frontier of Kashmir eastwards to China, has now been defined with comparative geographical exactness. The position of Sachu (or Saitu) in Mongolia may be taken as an obligator}7 point in modern map construction. The longitude value now adopted is 94° 54' E. of Greenwich, which is the revised value given by Prjevalski in the map accompanying the account of his fourth exploration into Central Asia. Other values are as follows :— Prjevalski, by his second and third explorations 94° 26' Krishna . . . . .94° 23' Carey and Dalgleish .... 94° 48' Littledale ..... 94° 49' Kreitner (wdth Szecheny’s expedition) . 94° 58' The longitude of Darchendo, or Ta Chien Lu, on the extreme east, may be accepted as another obligatory point. The adopted value by the Royal Geographical Society is 102° 12". Krishna gives 102° 15" Kreitner 102° 5" Baber 102°18" South and west the bounding territories are well fixed in geographical position by the Indian survey determinations of the value of Himalayan peaks. On the north the Chinese Turkestan explorations are now being brought into survey connexion wdth Kashmir and India. No longer do we regard the Kuen Lun mountains, which extend from the frontiers of Kashmir, north of Leh, almost due east to the Chinese province of Kansu, as the southern limit of the Gobi or Turkestan depression. This very remarkable longitudinal chain is undoubtedly the northern limit of the Chang Tang, the elevated highland steppes of Tibet; but from it there branches a minor system to the north-east from a point in about 83° E. longitude, which culminates in the Altyn Tagh, and extends eastwards in a continuous wTater-divide to the Nan Shan mountains, north of the Koko Nor basin. Thus between Tibet and the low-lying sands of Gobi w-e have, thrust in, a system of elevated valleys (Tsaidam), 8000 to 9000 feet above sea-level, forming an intermediate steppe between the highest regions and the lowest, east of Lob Nor. All this is comparatively new geography, and it goes far to explain wdiy the great trade routes from Peking to the west wrere pushed so far to the north. On the western edge of the Kashgar plains, the political boundary between Russia and China is now defined by the meridional range of Sarikol. This range (known to the ancients „ as Taurus, and in mediaeval times as Bolor) like Chinese many others of the most important great natural houaHarv mountain divisions of the wTorld, consists of two parallel chains, of which the western is the wTater-divide of the Pamirs, and the eastern (which has been known as the Kashgar or Kandar range) is split at intervals by lateral gorges to allow of the passage of the main drainage from the eastern Pamir slopes. It is on this eastern ridge that the highest peaks at present known north of the Himalaya have been fixed. Here is the Muztagh Ata of Sven Hedin (not to be confounded wdth the Muztagh range on the Kashmir frontier), whose height has been determined to be 24,000 feet above sea-level; and there are other peaks on this eastern ridge which may possibly be found to approach this value closely, wThen their altitude has been scientifically determined. The Sarikol range marks the position of the great water-divide between the Aralo-Caspian basin and the central system of hydrography terminating in the Lob Nor depression. Imntral r mediately between the Sarikol and the Kashgar (or C* Kandar) are the lowlands of the Sarikol valley, of which water_ the Taghdumbash Pamir forms a southern extension, The tri-junction of the boundaries of three great empires—Russia, China, and British India—is not inappropriately situated near the tri-junction of three great Asiatic mountain systems where the Sarikol range, reaching southwards to a junction wdth the Hindu Kush and the Muztagh ranges, defines the head of the Taghdumbash Pamir. From this point the Hindu Kush trends westwards and southwestwards, overlooking the narrow valley of the Panja (one of the main Oxus affluents on the north) till it merges beyond Kabul into the mountains wdiich separate Afghanistan from Afghan Turkestan.