CHAPTER XX
THE MYSTERY DEEPENS
When Challis and John crept down the hill that dark night, Royce remained for some time at the wall, listening anxiously for sounds which would indicate whether the Tubus had discovered them.
For a time all was silent; there was not even a rustle; he hoped all was well. But presently the thud of galloping horses and the shouts of men sent a shiver down his spine. Was his friend being pursued?
A moment's thought relieved his fears. If Challis had been caught, the negroes would not have needed to ride after him. If he had once got past them, they would hardly be aware of it. He concluded that something had caused the animals to stampede. Challis might be trusted to avoid being ridden down.
Reassured though he was, Royce spent an uneasy night. After setting a double watch at each corner of the fort, he turned in, but set his alarm clock to wake him in an hour. He then made a round of the fort, to assure himself that the sentries were not asleep.
It was not easy, as he knew, to keep negroes awake on guard. The necessity of waking so frequently, after short naps, was very wearing.
"By the time Tom gets back," he thought, "I shall be half dead with fatigue."
About dawn he had reason to be glad that he had not spared himself. He found the men on duty at the south-west corner fast asleep. Rousing them, not too gently, he looked out over the wall to see for himself whether there was any sign of the enemy.
His first impression was one of relief. There was no indication of anything unusual, so far as he could see in the grey dawn.
A second glance, however, raised a doubt. There seemed to be more bushes on the slope than he remembered on this side of the fort. Here and there, projecting slightly above the general contour, there were dark, shapeless masses.
He called up Kulana, who acted as interpreter in John's absence.
"You see those?" he said quietly. "What are they?"
The objects were very dim and indistinct. The man peered at them, and in a moment said, in the same hushed tone as Royce had used:
"Dem bushes, sah."
Kulana, however, was hardly awake yet. One of the negro guards, who had had time to collect himself, noticed Kulana and his master staring at something on the hillside. He, too, peered into the semi-darkness.
"Men!" he exclaimed excitedly.
"No, bushes!" rejoined Kulana.
They were raising their voices in dispute, each sticking to his opinion, and Royce bade them be silent. Unable to decide the matter himself, he felt that he dared take no risks. Quietly summoning the garrison, he sent them to their allotted posts behind the wall, ordering them to be careful not to show their heads above it.
Then he resolved to put the matter to the test. Taking his rifle, he fired just above the nearest of the suspicious objects, not directly aiming at it, hoping that fright would effect his purpose.
The result was immediate, and though not wholly unexpected, was none the less surprising. The harmless discharge of his rifle was followed by a movement recalling the effect of a gunshot on a covey of hidden birds. The hillside seemed to start into life and motion. A number of low, dark forms sprang up in the half-light, swiftly descended the hill, and disappeared in the mist on the level ground beyond.
"A surprise for them instead of the one they intended for me," thought Royce. "I hope they won't try it again; it is hateful to shoot the poor wretches, but there's nothing else for it if they attack."
Only the knowledge of the miseries these pests of the country had inflicted on scores of peaceable villages reconciled Royce to the part he felt himself called upon to play.
He seized the occasion to impress upon his men the necessity for watchfulness while on duty.
"Your falling asleep," he said to the two repentant sentries, "might have led to the capture of the fort, and the death or enslavement of all of us. Take care in future."
During the day it occurred to him that the men would be all the better for active employment. At the same time, in view of the attempted surprise, it was advisable still further to strengthen their defences.
Accordingly, he set them to dig a ditch a few feet inside the wall. The proper place for it was outside, of course; but to dig it there would expose them to danger. Moreover, the Tubus might fill it up or bridge it. If it were inside, on the other hand, it would form an unexpected obstacle should they scale the wall.
There was not enough water to make a moat of it; but, dug to a depth of several feet, it would seriously embarrass the attackers, even though dry.
The men at the north-east corner, when they had dug about six feet below the surface, came suddenly upon something hard, upon which the sharpened stones they used as spades made no impression. They reported the discovery to Royce, who went to the spot and jumped down so that he might examine the obstruction.
It proved to be a course of brickwork. Taking the spade, Royce dug the earth away from its edge for several feet, wondering what purpose the bricks served.
Perhaps, he thought, they were part of some building still more ancient than the fort itself. It would be interesting to excavate more thoroughly, and find out whether anything of value, in the shape of old weapons, coins, or pottery, lay beneath the foundations.
But that must be a task for the future. At present the business in hand was the completion of the ditch. The bricks being almost level with the bottom of the part which had already been dug out, he decided that it was unnecessary to remove them, and he ordered the men to go on with their work in another direction.
By dusk that evening the ditch was half finished. Royce, after eating his scanty supper, was sitting alone, tired out, wondering what had happened to Challis, whether he would succeed in getting help, how long it would be before he came back.
All at once he heard a shout of alarm, followed by a cry of pain. Springing up, he rushed in the direction of the sounds. The whole garrison was in a ferment, and two of the men had reached the scene before him.
"What is it?" he cried, thinking that perhaps some of the men had been quarrelling.
But on his arrival he found one of the Hausas groaning with pain, supported by his two comrades. They pointed to a gash in the man's thigh.
"Bring him along," said Royce to Kulana, deferring questions until he had rendered first-aid.
They carried the man to Royce's room. Royce took some lint from his medical stores, soaked it in water, and tied it tightly over the wound. He saw at once that the injury was not serious, and the cut, being clean, would heal in a few days.
"Now, how did it happen?" he asked.
The negro told Kulana that he had suddenly seen beside him a stranger, a man of immense size, very fierce-looking, with two long scars on each cheek. He had given a shout of alarm and rushed at the man, who was moving stealthily towards the well-yard. At the shout the stranger turned, dug his knife savagely into the Hausa's side, and rushed away.
Royce wished that he had questioned the man before. It would be hopeless to search for the intruder now. From the description, he had no doubt that it was Goruba, who had entered the fort for the second time in some mysterious way.
Royce was staggered. How had the man contrived again to get in unperceived? What sentries could cope with him? What could be his object in coming alone into the fort? Why was he running such risks in venturing unsupported among a garrison whom he knew to be well-armed and watchful?
"I must solve this mystery," Royce said to himself. "The men are scared out of their wits, and if this sort of thing is to happen their courage will melt away. There must be a secret entrance somewhere. To-morrow I'll search the place thoroughly again, though, upon my word, we have been through it so often that I can't for the life of me conceive where the rat's hole can be."
He gave the wounded man a sleeping-draught, did his best to calm the fears of the rest, and remained on guard all night, in case another alarm should create a panic.
