Denham, believing Boo-Khaloum to be acting honestly, went off to Tripoli to obtain the governor's sanction, but on his arrival there he obtained only evasive answers, and finally threatened to embark for England, where he said he would report the obstacles thrown in his way by the pacha, in the carrying out of the objects of the exploring expedition. These menaces produced no effect, and Denham actually set sail, and was about to land at Marseilles when he received a satisfactory message from the bey, begging him to return, and authorizing Boo-Khaloum to accompany him and his companions. On the 30th October Denham rejoined Oudney and Clapperton at Murzuk, finding them considerably weakened by fever and the effects of the climate. Denham, convinced that change of air would restore them to health, persuaded them to start and begin the journey by easy stages. He himself set out on the 20th of November with a caravan of merchants from Mesurata, Tripoli, Sockna, and Murzuk, escorted by 210 Arab warriors chosen from the most intelligent and docile of the tribes, and commanded by Boo-Khaloum. The expedition took the route followed by Lyon and soon reached Tegerry, which is the most southerly town of Fezzan, and the last before the traveller enters the desert of Bilma. Denham made a sketch of the castle of Tegerry from the southern bank of a salt lake near the town. Tegerry is entered by a low narrow vaulted passage leading to a gate in a second rampart. The wall is pierced with apertures which render the entrance by the narrow passage very difficult. Above the second gate there is also an aperture through which darts, and fire-brands may be hurled upon the besiegers, a mode of warfare once largely indulged in by the Arabs. Inside the town there are wells of fairly good water. Denham is of opinion that Tegerry restored, well-garrisoned and provisioned, could sustain a long siege. Its situation is delightful. It is surrounded by date-trees, and the water in the neighbourhood is excellent. A chain of low hills stretches away to the east. Snipes, ducks, and wild geese frequent the salt lakes near the town. Leaving Tegerry, the travellers entered a sandy desert, across which it would not have been easy to find the way, had it not been marked out by the skeletons of men and animals strewn along it, especially about the wells. "One of the skeletons we saw to-day," says Denham, "still looked quite fresh. The beard was on the chin, the features could be recognized. 'It is my slave,' exclaimed one of the merchants of the kafila. 'I left him near here four months ago.' 'Make haste and take him to the market!' cried a facetious slave merchant, 'lest some one else should claim him.'" [Illustration: A kafila of slaves. (Fac-simile of early engraving.)]