Tibet may be likened to a fortress surrounded by mighty ramparts. To the south the ramparts are double, the Himalayas and the Trans-Himalaya, and between the two is a moat partly filled with water--the Upper Indus and the Upper Brahmaputra. And Tibet is really a fortress and a defence in the rear of China. It is easily conceivable that a country surrounded by such huge mountain ranges must be very difficult of access, and the number of Europeans who have crossed Tibet is very small. The inaccessible position of the country has also had an influence on the people. Isolated and without communication with their neighbours, the people have taken their own course and have developed in a peculiar manner within their own boundaries. The northern third of the country is uninhabited. I once travelled for three months, and on another occasion for eighty-one days, without seeing a single human being. The middle part is thinly peopled by herdsmen, who roam about with their flocks of sheep and yaks, and live in black tents. Many of them also are skilful hunters of yaks and antelopes. Others gather salt on the dried-up beds of lakes, pack it in double-ended bags, and carry it on sheep to barter it for barley in the southern districts, which are the home of the great majority of Tibet's two or three million inhabitants. There are to be found not only nomads, but also settled people, dwelling in small villages of stone huts in the deeper river valleys, especially that of the Brahmaputra, and cultivating barley. A few towns also exist here; they are all small, the largest being Lhasa and Shigatse. When our journey takes us to India again we shall have an opportunity of learning about the religion of Buddha, which is called Buddhism. In a different form this religious creed found its way into Tibet a thousand years ago. Before this time a sort of natural religion prevailed, which peopled the mountains, rivers, lakes, and air with demons and spirits. Much of the old superstition was absorbed into the new teaching, and the combination is known by the name of Lamaism. There are 620 millions of Christians in the world and 400 million Buddhists; and of the Buddhists all the Tibetans and Mongolians, the Buriats in eastern Siberia, the Kalmukhs on the Volga, the peoples of Ladak, northern Nepal, Sikkim, and Bhutan are Lamaists.