Marco Polo has been resumed only in our days. But it is being prosecuted by many explorers armed with the resources of science, and protected by the respect with which the natives have learnt to regard the Western nations. From year to year the space still remaining to be explored becomes narrower; the main features of the mysterious Pamir are already determined; Northern and Western China have been traversed in every direction. But certain Tibetan districts still remain a terra incognita, pending the exploration of which many important geographical problems must remain unsolved. Asia may still be said to lack geographical unity in its relations with the history of man; for the interior remains but partially known, while the movements of the population and commerce continue still to be made by the seaward routes and coast regions.
| Fig. 12.—Chief Itineraries of Central Asia. | |||
| Scale 1 : 120,000,000. | |||
| |||
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Silk Route. | 
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Pundits. |
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Chinese in the fifth century. | 
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Gabet. |
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Hwen-T'sang. | 
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Francis Garnier. |
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Arabs. | 
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McCarthy. |
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Nicolo and Maffeo Polo. | 
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Richthofen. |
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Marco Polo. | 
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Elias, 1872. |
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Main Trade Route according to Pegoletti, 1310. | 
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Sosnovski. |
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Forsyth, 1870. | 
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Cooper. |
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Prjevalski. | 
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Armand David. |
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Schlagintweit. | ||
 3,000 Miles.
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The progress of trade and discovery must ultimately give to Asia the unity it now lacks, and the result must be a general shifting of equilibrium throughout the whole world. At no distant day the European railway system will be continued eastwards, connecting the cities of the Bosporus with those of India, and enabling goods to be forwarded without break from the Vistula to the Indus basin. Travellers will then flock to those still unknown regions of Eastern Tibet,
