"I do not know," Dan answered tartly. "I expect her every moment, but it is idle to conceal from you, Monsieur, that we are much concerned as to her absence."
The Marquis grew sympathetic,—optimistically sympathetic. Tom clutched at his re-assuring words, but Dan was even more irritated by the silence that Monsieur de Boisdhyver had maintained throughout the day.
Directly after supper Dan went into his mother's parlour, leaving the others to their own devices. The Marquis settled himself near the fire and was soon absorbed in reading an old folio; Tom wandered restlessly about, now up and down the long bar, now in the corridors, now on the gallery and in the court without.
The night, after the bright day, had set in raw and cold; a damp breeze blew from the southwest, and gave promise both of wind and rain. From his position under the Red Oak, Tom could see the red and green lights of The Southern Cross at her moorings in the Cove below, and across the Neck the lighted windows of the House on the Dunes. Over all else the night had cast its black damp mantle.
As he stood watching, deeply anxious for the welfare of the girl he loved, he noticed a new light appear in one of the upper windows of the House on the Dunes—not yellow as is the light of candles, but green like the light on the port side of the clipper in the Cove. Had he not seen the lights from the other windows he could have thought it was another ship on the ocean side of the Neck.
He looked for a long time at the tiny spark in the distance, wondering what whim had induced Mrs. Meath to shade her candles with so deep a green. As he strolled back toward the Inn, he glanced through the windows of the bar where the Marquis still read by the fireside. Suddenly the old gentleman, as Tom curiously watched him, laid his book down on the table and rose from his chair. He looked about the room and then advanced to the window. Tom instinctively slipped behind the trunk of the great oak. Monsieur de Boisdhyver stood for several moments peering into the darkness. Then he turned away and crossed the room to the door into the front hall. It flashed through Tom's mind that possibly the Marquis had started on another of his mysterious tours. He ran down again into the court far enough from the house to command a view of the entire facade, and watched curiously, particularly the north wing. All was dark, save for the lights below.
Suddenly he saw the flicker of a candle in one of the windows, not of the north wing, but of the south. A moment's glance, and he made sure that it was the room occupied as a sleeping apartment by Monsieur de Boisdhyver.
The Marquis was standing by the window, with his face pressed close to the pane, peering out into the night. He still held the candle in his hand. To Dan's surprise, he placed it carefully on the broad window-sill, and drew down the dark shade to within a foot of the sill, blotting out all save a narrow band of light. Then the Marquis disappeared for several moments into the interior of the room. Dan was about to turn back into the house, when again Monsieur de Boisdhyver came to the window. He did not raise the shade, but inserted between the windowpane and the candle a strip of dark green paper. It was translucent and had the effect of sending a beam of green light southward, across the meadows and the dunes, to meet—Tom suddenly realized—the rays of the green light from the House on the Dunes.
Was it a signal being exchanged, and between whom? The coincidence of green lights from the Inn and the House on the Dunes, at the same moment, was too marked to be without significance. To what end was the Marquis de Boisdhyver exchanging mysterious signals with some one in that lonely farmhouse, and what did they mean?
Tom repressed his agitation and remained for some time watching the two green lights that glowed toward one another over the dark landscape.