An idea flashed into his mind.
"John," he said, "go out ahead and see where those horses are, how many there are, and what the Tubus are doing."
It was twenty minutes before John returned. His report was interesting, and would have been alarming, but for the idea which had occurred to Challis.
About fifty of the Tubus, said John, were about to ride off in a northerly direction. Each man had four or five horses in his charge, so that they were probably going to a grazing ground somewhere near.
The rest of the men in the north-west camp were hard at work making ladders. It was clear that another attack was to be made on the fort. The ladders previously used had been left behind under the walls.
It was clear, too, that the enemy had no suspicion of any attempt from the outside to raise the siege. Confident in their numbers, they had taken no steps to guard against an attack from the rear.
"With luck we have them!" said Challis to himself, and turned to give final orders to his expectant men.
CHAPTER XXXI
THE LAST FIGHT
Challis wished to get as near as possible to the Tubus who were collecting the horses without being discovered. Accordingly he drew out his men in line over a long front, and passed the word along that they must keep a strict silence.