On the right, at the angle formed by the junction of the two streams, there was a low-lying patch of dry land, triangular in shape--an island inclosed by streams and the swamp. While this island was at the present time dry, Challis had no doubt that it was submerged when the streams were flooded by the rains. Challis had considered the possibility of being attacked before he was ready to move out towards the fort with his little army. He decided that such an attack, if it occurred, would most likely be made from this direction, the ground being more level and open than on any other side. It was clear that the best point at which to meet the attack would be where the swamp approached most closely to the steep hill on the left. Including the shallow bed of the stream, about fifty feet wide, there were altogether about a hundred and fifty feet of firm dry land between the swamp and the hillside, except for the stream, now little more than a yard across. Here his men could best make their stand. Since his arrival at the cave, Challis had insisted on an elementary precaution which it is the habit of negroes to neglect. Every morning at dawn he had sent out scouts in a southward direction, to give notice if the enemy approached. These men took sufficient food for the day, and returned at nightfall. He arranged that the line of scouts should extend for several miles towards the enemy's country, each man posting himself within hailing distance of the next. By this means he ensured that he should receive warning within a few seconds of the sighting of the enemy by the remotest man. On the sixth day after his arrival he had reason to be glad of his forethought. About noon the nearest scout ran in with the news that a force of Tubus was approaching from the direction of the river. A fact that somewhat surprised him was that their line of march would bring them direct to the cave, not to the village whence the people had migrated. It seemed as if they had information of what was going on. Was it possible that there was a traitor in the camp? With a little more experience of negro life he would have divined the true explanation. The story of his doings had spread for many miles around, gaining in magnitude with every repetition. Certain of the neighbouring tribes purchased immunity from attack by spying for the Tubus, and there was no doubt that some of these people had carried to Goruba the report that a white man was making big medicine at the cave. But it was not at all likely that Goruba had any idea who the white man was, unless he had already stormed the fort and discovered that it contained one white man instead of two. The probability was that he was coming or had sent to test the truth of the story he had heard. The white man might be a missionary, unlikely to trouble him.