The young men took leave of their colleagues, and descended the mountain in the obscurity of night, having been preceded by the pioneer and two sailors, one English and one Russian. The mooring was loosened, and the frail boat turned quietly across the lake. CHAPTER XX. STANDING A SIEGE. Not without anxiety had the astronomers witnessed the departure of their young colleagues: they could not tell what dangers awaited them in that unknown country. Mokoum tried to reassure them by praising the courage of the pioneer, and besides, he said, the Makololos were too much occupied around Mount Scorzef to beat the country to the north of Lake Ngami. He instinctively felt that the Colonel and his party were in a more dangerous position than the two young astronomers. [Illustration: On Guard on Mount Scorzef.] The sailors and Mokoum kept watch in turns through the night. But "the reptiles," as the bushman termed the Makololos, did not venture another attack. They seemed to be waiting for reinforcements, in order to invade the mountain from all sides, and overcome by their numbers the resistance of the besieged. The hunter was not mistaken in his conjectures; and when daylight appeared Colonel Everest perceived a sensible increase in the number of the natives. Their camp, carefully arranged round the base of the mountain, shut off escape on every side except that towards the lake. This side could not be invested, so that unless unforeseen circumstances occurred, retreat to the water was always practicable. But the Europeans had no thought of escaping: they occupied a post of honour, and were all agreed that it must not be abandoned. No allusion was ever made to the war between England and Russia, and both parties strove together to accomplish their scientific labour. The interval of waiting for the signal on Mount Volquiria was employed in completing the measurement of the preceding triangle and in finding the exact latitude of Mount Scorzef by means of the altitudes of the stars.