The defences of the slopes right and left then engaged Tom's attention. There were not enough trees on the spot to form effective barricades, and the only means of checking the enemy if they scaled the low heights was to dig trenches. The labour would be long and toilsome, for the ground must first be cleared of the brushwood; but in no other way could the enemy be prevented from swarming down into the nullah. At the end of a week the western and eastern slopes, for about thirty yards from the end of the nullah, were each scored with a deep trench, fortified with a parapet constructed of the earth that had been removed.
A second line of defence might be necessary, and for this there was no better position than the bend of the nullah, nearly half a mile to the north. The sides being here steep, almost perpendicular, it was impossible to haul trees from the forest above for a breastwork like that at the entrance; so Tom had the bed of the nullah cleared of cover for a space of about two hundred yards, and a trench with a strong parapet carried from side to side.
The work was still unfinished when one day the scouts, for the first time, reported that they had sighted the enemy. About ten miles away they had seen a band of young natives marching towards Bismarckburg in charge of a German officer and a small party of askaris. It seemed clear that these negroes were recruits for the German forces, and Tom, relying on the scouts' statement that the askaris were few in number, decided to make an attempt to prevent the natives from being turned into what Captain Goltermann had called "black Germans."
The party, when sighted, was marching very slowly, following a native path that wound through dense bush, and crossed the track between the plantation and the nullah. Tom calculated that if he started at once he would arrive at a position where he might ambush the enemy just before they reached the road to Bismarckburg. With his untrained men he could not risk a stand-up fight; but he hoped that the advantage of surprise, if the patrol was really so small as the scouts declared, would enable him to achieve his end without fighting.
Selecting twenty of the men who had been with him in his little action in the forest, he led them out, with Mwesa, and followed rapidly on the heels of the scouts. In about an hour and a half they came to the spot he had fixed on, and while he posted the men in the bush on both sides of the track, he sent the scouts to worm their way eastward and watch for the enemy. The interval before they returned was long enough for the men and himself to regain breath. It was perhaps half an hour later when they came quietly through the brushwood with news that the enemy were in sight.
At the place where Tom had posted himself the track ran fairly straight for more than a hundred yards, and he was able to take stock of the party with which he had to deal while it was still distant. First came two unarmed natives, evidently guides; then a German non-commissioned officer; behind him two German privates, followed by a string of negroes. The tail of the party was out of sight.
Seeing how few were the armed men at the head of the column, Tom instantly resolved on a bold course. His own men were concealed among the bushes; they had their orders. He stepped out on to the track, accompanied only by Mwesa, just before the negro guides reached him. They halted in surprise, and looked round towards the German thirty yards behind.
"Tell them to come on, Mwesa," said Tom.
The boy called to them, and they at once hastened on. Tom spoke to them in German, but they evidently did not understand him. Meanwhile the German sergeant had quickened his step, and hearing German on the lips of the stranger, he approached unsuspiciously, halted, clicked his heels together, and waited, as a well-trained subordinate will, for his superior to address him.
"Halt your men, Sergeant," said Tom.