Hitherto the party had met no natives; but Coja now informed his master that the people of these parts were very bad, and advised that they should go slowly, so that no stragglers should be left to be set on and robbed--if not maltreated or killed. Mr. Halliday was somewhat troubled at the thought of unfriendly natives between his prospective estate and the outposts of civilization; but consoled himself with the reflection that the area of settlements was rapidly enlarging, and the country in the settled parts being brought thoroughly under control. The country beyond the Thika river proved to be more difficult than any that had hitherto been traversed. Bare rocky hills, cut by deep and dangerous ravines, alternated with stretches of long coarse grass and dense thorny scrub, impenetrable save by low tunnels made by roaming hippopotami. As they burrowed painfully through these tunnels, they were oppressed by the suffocating heat, their clothes were torn by the thorns, and their skin irritated by the multitudinous insects. It was like wandering through a complex maze, the hippo paths twisting this way and that in apparently aimless fashion, though Coja said they were a clear sign of the neighbourhood of water. After a whole day spent in this fatiguing march the party came abruptly upon a broad river, flowing with swift but almost noiseless current between banks clad with noble palms and every species of tropical vegetation, amid which countless throngs of monkeys desported themselves, and birds of many colours darted this way and that like fragments of a rainbow. Mr. Halliday pitched his camp for the night above the river, and for the first time the porters surrounded it with a boma--a close fence of thorn bushes, which they constructed with wonderful celerity. For the first time, too, a watch was kept, the porters being told off to take turns at sentry-go. It occurred to Mr. Halliday, waking in the middle of the night, to see whether the sentry was alert at his post, and he was not greatly surprised to find him fast asleep. He shook him up and rated him very soundly, his reprimand being, perhaps, the more impressive because delivered in a tongue which the man did not understand. Mr. Halliday slept no more that night, coming to the conclusion that if it was necessary to keep watch, the porters were not to be entrusted with the task.