"The relief," whispered Major Marchand, when they had gone. "They may be swarming down this hill after us in a few minutes."
The two hurried on. The keen feeling of peril and adventure gripped Ruth Fielding's soul. It was not with fear that she trembled now.
At length they halted in a pitch-black place, which might have been almost anything but the sheepfold Major Marchand told Ruth it was. He produced an officer's trench whistle and blew a long and peculiar blast on it.
"Now, hush!" he whispered. "It is against usage to use these whistles for anything but the command to go over the top at 'zero.' Necessity, however, Mademoiselle, knows no law."
They waited. Not a sound answered. There was no stir on any side of them. Ruth's fears seemed quenched entirely. Now a feeling of exultation gripped her. She was fairly into this adventure. It was too late to go back.
The major blew the whistle a second time and in the same way. Suddenly a dark figure loomed before them. There was a word In French spoken out of the darkness. It was not the password the Major had given the American sentinel.
"Come, Mademoiselle," said the major. "Give me your hand again."
Ruth's warm hand slipped confidently into his enclosing palm. The Frenchman's courtesy and unfailing gentleness had assured her that she was perfectly safe in his care.
They left the sheepfold, the second man, whoever he was, moving ahead to guide them. Even in the open it was now very dark. There was no moon, and the stars were faint and seemed very far away.
Finally Ruth saw that a ridge of land confronted them; but they did not climb its face. Instead, they followed a winding path along its foot, which soon, to the girl's amazement, became a tunnel. It was dimly lit with an electric bulb here and there along its winding length.