“But they will find the wireless,” said the woman.  “They are sure to use the towers for observation, and they will find it.”

“In that case,” said the officer, “you will suggest to them that we fled in such haste we had no time to dismantle it.  Of course, you had no knowledge that it existed, or, as a loyal French woman, you would have at once told them.”  To emphasize his next words the officer pointed at her:  “Under no circumstances,” he continued, “must you be suspected.  If they should take Briand in the act, should they have even the least doubt concerning him, you must repudiate him entirely.  If necessary, to keep your own skirts clear, it would be your duty yourself to denounce him as a spy.”

“Your first orders,” said the woman, “were to tell them Briand had been long in my service; that I brought him from my home in Laon.”

“He might be in your service for years,” returned the colonel, “and you not know he was a German agent.”

“If to save myself I inform upon him,” said Marie, “of course you know you will lose him.”

The officer shrugged his shoulders.  “A wireless operator,” he retorted, “we can replace.  But for you, and for the service you are to render in Paris, we have no substitute. You must not be found out.  You are invaluable.”

The spy inclined her head.  “I thank you,” she said.

The officer sputtered indignantly.

“It is not a compliment,” he exclaimed; “it is an order.  You must not be found out!”

Withdrawn some two hundred yards from the Paris road, the chateau stood upon a wooded hill.  Except directly in front, trees of great height surrounded it.  The tips of their branches brushed the windows; interlacing, they continued until they overhung the wall of the estate.  Where it ran with the road the wall gave way to a lofty gate and iron fence, through which those passing could see a stretch of noble turf, as wide as a polo-field, borders of flowers disappearing under the shadows of the trees; and the chateau itself, with its terrace, its many windows, its high-pitched, sloping roof, broken by towers and turrets.

Through the remainder of the night there came from the road to those in the chateau the roar and rumbling of the army in retreat.  It moved without panic, disorder, or haste, but unceasingly.  Not for an instant was there a breathing-spell.  And when the sun rose, the three spies—­the two women and the chauffeur—­who in the great chateau were now alone, could see as well as hear the gray column of steel rolling past below them.

The spies knew that the gray column had reached Claye, had stood within fifteen miles of Paris, and then upon Paris had turned its back.  They knew also that the reverberations from the direction of Meaux, that each moment grew more loud and savage, were the French “seventy-fives” whipping the gray column forward.  Of what they felt the Germans did not speak.  In silence they looked at each other, and in the eyes of Marie was bitterness and resolve.