The Commission had four repeating circles: two for measuring angles, and two more with vertical circles for obtaining zenith distances, and so calculating in a single night, to the smallest fraction of a second, the latitude of any station. And indeed, in this important survey, it was not only necessary to obtain the value of the angles of the triangles, but also to measure the meridian altitude of the stars, that being equal to the latitude of each station. The work began on the 14th of April. Colonel Everest, Zorn, and Palander observed the angle at the south-east extremity of the base, while Strux, Emery, and Sir John Murray observed that at the north-west extremity. Meantime the camp was raised, and the bullocks harnessed, and Mokoum conducted the caravan to the first station as a halting-place. Two caravans, with their drivers, accompanied the observers, to carry the instruments. The weather was bright, but had the atmosphere been unfavourable by day, the observations would have been made by night by means of reverberators or electric lamps. On the first day, the two angles were measured, and the result inscribed on the double register; and the astronomers all met in the evening at the camp which had been formed round the tree which had served for their point of sight. It was an immense baobab, more than 80 feet in circumference. Its syenite-coloured bark gave it a peculiar appearance. The whole caravan found room beneath its wide branches, which were inhabited by crowds of squirrels, which greedily devoured the white pulp of its egg-shaped fruit. Supper was prepared for the Europeans by the ship's cook. There was no lack of venison, for the hunters had scoured the neighbourhood, and killed some antelopes; and soon the air was filled with an odour of broiled meat, which still further aroused the appetite of the hungry savants. [Illustration: Encampment under an immense Baobab.] After the comforting repast, the astronomers retired to their respective waggons, whilst Mokoum placed sentinels round the camp. Large fires of the dead branches of the baobab burnt throughout the night, and kept at a respectful distance the tawny beasts, who were attracted by the odour of the reeking flesh. After two hours' sleep, however, Emery and Zorn got up, their observations not yet finished. They must find the altitudes of some stars to determine the latitude of the station, and both, regardless of the day's fatigues, stood at their telescopes, and rigorously determined the change of zenith caused by the removal from the first station to the second, while the laugh of the hyena and the roar of the lion resounded over the sombre plain. CHAPTER IX. THE KRAAL.