"No use!" said Paul, disgustedly. "He got away from us. But I don't suppose it would have done us any good to catch him. We couldn't have done anything—hello!"
He ended with an exclamation of surprise, and stooped over. They were at the foot of the fence the flying figure had climbed a moment before.
"What is it, Paul?" asked Arthur, eagerly.
"This!" said Paul. He held up a small black pocket-book, and from it he took a package of papers, wrapped in oil silk. "I struck against it with my foot! I wonder if that man who was running could have dropped it?"
It was almost dark by this time; too dark, at any rate, for them to be able to see the papers. But then Arthur remembered the pocket flashlight he carried and produced it, switching on the light.
"Let's have a look," he said.
They unwrapped the oil silk covering. And, at the first sight of what was within it, they gasped. They were holding in their hands a complete sketch of the fort of Boncelles, the most important of the works defending Liege to the southwest. Before they could examine it more fully there was a shout from the fence. The spy had missed his papers. They saw him for a moment. But now it was their turn to run.