"I will come in the aeroplane, boy; we have enough to bring us here."

The boy, rather crestfallen, had to trot to keep pace with Kenneth's long strides. He had hoped to receive a few pfennigs for carrying the petrol. Kenneth, busy with his thoughts, forgot the youngster until he was paying the civil farm people for his food. Then, catching sight of the boy's woebegone face, he handed him a silver coin that drove the clouds away. It was lucky, he reflected, that he still had some German money in his possession. A Belgian coin would have given him away.

After five minutes' talk with Pariset, out of earshot of the people, who had gathered about at a little distance, they once more took the air. They had managed to compress a good deal into that brief conversation. Pariset had accepted Kenneth's suggestion with delight. The problem, they agreed, was twofold: they had first to deal with the escort, then with the guns--if they were guns. When they soared away over the meadow they had formed a clear idea of the means by which they would attempt to solve it.

Making a wide sweep, east, north, and west, they approached the causeway south of the spot where the breakdown had occurred. The sight of a Taube monoplane flying obliquely over the road aroused curiosity but no suspicion in the minds of the Germans. But suddenly one of them gave a shout. Next moment a small bomb fell close beside one of the lorries, throwing up a shower of dust and stones. The engineers scuttled away; the troopers rushed to their horses, which, startled by the noise of the explosion, were threatening to stampede.

Pariset banked the aeroplane steeply and wheeled round. As it passed again over the causeway, Kenneth dropped another bomb, which fell close to the first. The men on foot were rushing wildly up the road; on the open fields there was no cover. Most of the troopers had mounted; some had seized their rifles and were firing. But the sight of the aeroplane wheeling again struck them with panic, and with a shout they dashed after their comrades, galloping across the fields.

The aeroplane followed up the fugitives. Owing to its speed, Pariset had to steer a zigzag course in order not to overtake them. Each time it wheeled he contrived to bring it close behind the rearmost horseman, like a sheep dog driving a flock, and Kenneth dropped a bomb to hurry the pace.

They kept up the chase for some minutes; then, there being no sign of rallying, they darted back to the causeway, where the traction engines and lorries now stood deserted. The level field on one side afforded a good alighting place. They came to the ground, sprang from their seats, and as they ran to the causeway noticed one or two men lying wounded.

"We simply haven't time to attend to them," panted Pariset. "The fellows will be riding back in a minute."

They reached the unwieldy vehicles. The impressions of the moment came back to them afterwards--the huge wheels with their grooved rims, the deep ruts they had carved in the road. There were plenty of tools lying about. Kenneth cut the lashings of one of the tarpaulin covers, stripped off the cover, and found, as he had expected, that beneath it lay a portion of a huge weapon, half gun, half mortar, with a bore seventeen inches in diameter.

"It's not the breech block; try the next lorry," urged Pariset.