They set off together, walking rapidly over the fields. Turning into a lane, they came suddenly face to face with a farm boy of about sixteen years. His jaw dropped, and a look of terror showed in his eyes when he saw the German uniforms. Pariset spoke to him rapidly in Walloon, and gave him money. Thus reassured, he agreed to conduct Kenneth across the hill to the path which Pariset had mentioned.
"Good luck!" said Pariset, as they parted. "Don't risk too much. If the stratagem fails, make your way back to the same spot."
Kenneth carried the gelignite and the battery. He gave the pick-axe to the boy. Pariset had learnt from him that no Germans had been seen on the lanes and roads, but they walked across the fields under cover of the hedgerows in case patrols or foraging parties should appear.
Their course brought them within half an hour to a field some little distance above the bridge. Kenneth dismissed the boy, and keeping under cover to avoid observation from the trains, which were stationary in the places where he had seen them forty minutes before, he crept as near to the bridge as he dared, and waited. He heard the water lapping the piers, the voices of the guards at the nearer end, the distant hiss of the locomotive of the troop train blowing off steam--and then a faint deep burr, growing louder moment by moment.
The guards raised their voices.
"Another Taube," said one.
"He's flying very high," said another. "Thinks we are Belgians, perhaps."
"But he's coming down," said the third. "Look at that swoop! It fairly makes me sick to see him."
Kenneth, posted under cover, was not yet able to see the aeroplane, but from the silence that fell upon the guards he guessed that Pariset was executing one of those steep dives which make the onlooker hold his breath.
"I hope he won't come too low," he thought.