After waiting a little and hearing no more, Tom went again to the window. The rain had begun now and the wind was blowing a gale. Suddenly Pembroke discerned a light shining from the window next the very one from which he was peering into the darkness,--the steady glow of a deep red light.
"Another signal!" he murmured; then waited to see if it would be answered by the House on the Dunes. Perhaps fifteen minutes passed, and then, suddenly, there gleamed through the rain and dark, a tiny bit of red flame, just where the House on the Dunes must be. A little later the red lamp on the _Southern Cross_ performed a fantastic ascension to what Pembroke took to be the masthead.
The red light in the neighbouring window was extinguished. Almost instantly the red spark on the Dunes disappeared, and in a few moments the schooner's lamp began its descent. Simultaneously they glowed again and the ship's light danced upward; then the two red lights on shore vanished and the lamp on the _Southern Cross_ sank to its proper place and stayed there.
Of one thing Tom was sure: The Marquis, the lady at the House on the Dunes, and the skipper of the schooner in the Cove, were in collusion. Of another thing he felt almost equally certain: the red light was a signal of danger, and the message of danger flashed across the night was the fact that he and Dan were not safe asleep in bed.
For a long time he watched, keen with excitement; listened patiently; started at every sound. But nothing more unusual did he hear that night than the roar of the wind, the dash of the brawling southeaster against the panes, and the groans of the old house, shaken by the storm. Toward morning he crept back to bed and fell instantly into a deep and dreamless sleep.
While Tom was thus watching and sleeping a somewhat different experience had fallen to the lot of Dan Frost. He had no definite plan in making a midnight visit to the vicinity of the House on the Dunes, but he hoped to discover some clue to the surrounding mysteries. From time to time during the day he had taken his field glasses to one of the upper rooms of the Inn, and scanned the countryside but nothing unusual seemed astir in the white world without. The _Southern Cross_ had lain on the surface of the little cove all day, swaying with wind and tide, no sign of activity upon her decks. It was after ten when he started forth. The night was not quite dark, for the full moon was shining somewhere behind the thick veil of clouds. Earlier in the evening Dan had intended to go boldly to the House itself and demand an interview with old Mrs. Meath; but he reflected that he would probably be met with the excuse that Mrs. Meath was ill, and he did not know how he could force himself in, particularly past the barrier of Madame de la Fontaine's charming manner.