There are several varieties possessing this valuable quality, but those of Kashmir, Tibet and Mongolia are the most esteemed.
Yet Tsaidam is geographically but a northern extension of the great Tibetan plateau, and in most of its essential physical features it is more closely allied to the Chang-t'ang of the south than to the great sandy depressions of Chinese Turkestan or Mongolia on the north.
From Mongolia come leather, saddlery, sheep and horses, with coral, amber and small diamonds from European sources; from Kham perfumes, fruits, furs and inlaid metal saddlery; from Sikkim and Bhutan rice, musk, sugar-balls and tobacco; from Nepal broadcloth, indigo, brasswork, coral, pearls, sugar, spices, drugs and Indian manufactures; from Ladak saffron, dried fruits and articles from India.
No great armies have ever crossed Tibet to invade India; even those of Jenghiz Khan took the circuitous route via Bokhara and Afghanistan, not the direct route from Mongolia across Tibet.
Hudson Taylor, the founder of the China Inland Mission, and James Gilmour, the apostle of Mongolia, are pre-eminent.