At seven o’clock next morning, equipped with the needful apparatus, they ascended from their headquarters in the Taube monoplane, took an easterly course, then swung southward and passed between the Flemelle and Boncelles forts. It was a beautiful summer morning. The country was bathed in sunlight, and no warlike sounds disturbed the still air. But south of the town clouds of dust hung over every road, and they caught sight of masses of men moving northward, the sun glinting on weapons and the spikes of helmets. Pariset, in the observer’s seat, felt sick at heart. How was it possible for the little Belgian army to resist these immense hordes? The well-known shape of the aeroplane (they no longer showed the Russian flag) purchased immunity. They flew over the railway, then over the Meuse north of Huy, then sweeping to the east soon came in sight of the Ourthe winding between meadows and precipitous cliffs, and the railway to Neufchâteau. The valley broadened out. Instructed by Pariset, Kenneth steered the monoplane over the village of Hamoir on the left bank. Almost immediately afterwards they came above the cluster of houses at Sy, and the bridge crossing the gorge, beyond which the railway entered the tunnel. On the north side of the bridge stood a long goods train, apparently waiting the signal to proceed. On the south side, part in, part out of the tunnel, was a train of passenger coaches, gaily bedecked with leafy branches of trees. A few soldiers had got out of the train, and were sitting smoking in the meadow. At each end of the bridge four guards were posted. The aeroplane passed over the cliff through which the tunnel ran, then bore to the left in the direction of Werbomont and was soon out of sight from the bridge. Choosing a lonely field sheltered by a wood, Kenneth brought the machine to the ground. "We can’t destroy the bridge with bombs," said Pariset, "but it’s just possible to do it with the gelignite if you are game." "What’s your idea?" asked Kenneth. "There’s clearly a block on the line somewhere to the north. It may be a long time before it is cleared, giving us just the opportunity we want. There’s a path through the fields on the left bank, leading to the bridge. It seems fairly covered. My idea is that you should go down to the bridge with the gelignite." "But it is guarded," Kenneth interrupted. "Don’t be impatient. I was going on to say that I will fly over the bridge and stampede the guards. That will give you a chance to creep up. Your uniform will protect you long enough for the purpose, I hope. The Germans won’t suspect you until the explosion occurs. Then it will be a ticklish moment. The fellows who have got out of the train may fire at you; but they are a good distance away, and you ought to have time to rush back under cover before they can do any damage. I’ll be ready to pick you up. Or, if you like, I’ll take the gelignite and you drop the bombs."