sand five hundred feet! To the difficulties afforded by the elevation were added attacks from predatory tribes, the Jegrais, which had to be repelled by fighting. He was not allowed to visit Lassa, although he was granted an interview with a deputation from the Holy City, who came to his camp at the foot of the Bumsa Mountain, sixteen thousand four hundred feet above the sea. "Again," he sorrowfully writes, "was my effort to penetrate to the capital of Thibet baffled by barbarian prejudices and the fanaticism of a stupid people. Now, when the greatest obstacles had been overcome, when everything had been smoothed away, when I had the object of my desires so near to my eye, I had again to turn back without accomplishing my purpose. It was a severe trial to give it up." He returned, through a moderately high spur of the Kuen-Lun range—which he named the Marco Polo Mountains, after the old Venetian traveler—and another unknown range, to Zaidam. On the 31st of January, 1850, after four and a half months of wandering in Thibet, he entered the station of Dsun-Lassak. This ended the second period of his expedition. The third period was passed in Zaidam, and partly in the Kuku-Nor, whence he undertook a journey of exploration to the sources of the Chuan-Chi, or Yellow River, which he followed from the Kuku-Nor southward into the northeastern spurs of the Thibetan foot-hills. He wanted to solve what had always been a riddle even to the Chinese. He returned to the Kuku-Nor, and struck from it upon the old road from Ala-Shan to Urga, which he had traversed in 1873. The fullest and most accurate information which geography has gained of the regions through which he traveled is what he has given it.
This journey was characterized by Dr. Petermann as the crown of Central Asiatic exploration, and as equal in importance to Stanley's journey down the Congo, or even to the attainment of the pole. Of its results, "Nature" said, in a summary of them, that the traveler's observations would be "of special value to the ethnologist, as containing important details concerning the various peoples he met with. The zoologist and botanist will also find much to interest him." In its notice of the book, the same journal referred to the part of the narrative describing what the author observed during his stay at Lob-Nor concerning the migrations of birds as being of exceptional value. The Royal Geographical Society, in April, 1879, awarded a gold medal to Colonel Prejevalski, "for the great additions he has made to our knowledge of Central and Eastern High Asia, by his successive expeditions into the unexplored parts of the great plateau of Mongolia and the lofty deserts of Western Thibet, and for the admirable way in which he has described the regions traversed by him in the published narratives of his journeys."
No amount of adventure satisfies a traveler, and Prejevalski was not satisfied with the excursions he had already made. At the close of his book, describing his third expedition, he says: "The joy
