“This must be another way to the shore,” said the King, coming to a standstill; “And there must be rocks or caverns near. Hark how the waves thunder and reverberate through some deep hollow!”

Sir Roger listened, and heard the boom of water rolling in and rolling out again, with the regularity and rhythm of an organ swell, but he caught an echo of something else besides, which piqued his curiosity and provoked him to a touch of unusual excitement,—it was the sweet and apparently quickly suppressed sound of a woman’s laughter. He glanced at his Royal master, and saw at once that he, too, had sharp ears for that silvery cadence of mirth, for his eyes flashed into a smile.

“On, Roger,” he said softly; “We are close on the heels of the problem!”

But they had only pressed forward a few steps when they were again brought to a sudden pause. A voice, whose gruffly mellow accents were familiar to both of them, was speaking within evidently close range, and the King, with a warning look, motioned De Launay back a pace or two, himself withdrawing a little into the shadow of the trees.

“Ach! Do not sing, my princess!” said the voice; “For if you open your rosy mouth of music, all the birds of the air, and all the little fishes of the sea will come to listen! And, who knows! Someone more dangerous than either a bird or a fish may listen also!”

The King grasped De Launay by the arm.

“Was I not right?” he whispered. “There is no mistaking Von Glauben’s accent!”

Sir Roger looked, as he felt, utterly bewildered. In his own mind he felt it very difficult to associate the Professor with a love affair. Yet things certainly seemed pointing to some entanglement of the sort. Suddenly the King held up an admonitory finger.

“Listen!” he said.

Another voice spoke, rich and clear, and sweet as honey.