"Good heavens! what it is to be without pencil and paper!" he groaned. But he managed with a spear-head to scratch on a stone a rough diagram of the machine, as nearly as he remembered it, and then immediately set to work to construct a model.
There was plenty of wood in the village, and it took very little time to hammer together the square framework, and to chisel out the grooved beam on which the missile was to run. While this was being done he set some of the Bairo to twist two many-stranded ropes, and the native smiths to forge an iron handle for his winch. When this was fixed in its place at the bottom of the grooved plank, and the ropes securely fastened at each side of the frame, he placed one of the fireballs in front of the cross rope on the plank, sloped this downwards at an angle of forty-five degrees, and drew the rope back by means of the winch until it was stretched to its utmost tension and almost as tight as a steel spring. Then he released his hold of the handle, it flew round, the spring was suddenly relaxed, and the ball shot along the groove and over the stockade, falling some ten yards beyond.
"I'll have a welcome ready for the Arabs if they return," he thought, delighted at the success of his experiment.
Some three hours after the downpour had ceased, the Arabs came back in stronger force, again bearing their palisades. Tom allowed them to arrive within five yards of the trench, and then let fly a piece of rock from his balista. A tremendous cheer arose from the crowd of wondering negroes as the missile sped with sure aim to the very middle of the palisade, with such force that it tore a hole through skin and wicker-work, and struck a man behind.
The Arabs were startled, as they might well be, and halted. Before they had made up their minds what to do, another missile struck the palisade, and ricochetted across it, inflicting a blow on one of the Arabs that would have killed him if its force had not been partly broken. Another stone, and another, and then the enemy hesitated no longer; they dropped their palisade, flung down their tools, and bolted for their lives. Mocking jeers and exultant laughter followed them, and then a shower of arrows, and four or five of them dropped. Tom ordered his men to cease shooting, and allowed the wounded to be carried off by their friends.