This officer belonged to the engineering corps, and directed, at the same time, the work of repairs within the citadel, in charge of a civilian contractor.

Taking into consideration the rank of his prisoner, the captain permitted the Marquis to have with him his orderly, an Alsatian, who twice a day brought from the inn his chief’s repasts.  This functionary had permission also, from ten o’clock in the morning until sunset, to promenade in the court under the eye of the sentinel on guard at the entrance.  At five o’clock in the evening, the officer of the landwehr politely shut up his guest in his prison, double-locked the door, put the key in his pocket, and appeared no more until the next morning.

The middle of November had arrived; heavy snows had already fallen, and the prisoner amused himself by constructing fortifications of snow—­ a work which his amiable jailer followed with a professional interest, giving him advice regarding modifications proper to introduce in the defense of certain places, himself putting a finger in the pie in support of his demonstration.

This sort of amusement was followed so industriously that in a few days a kind of rampart was erected in front of the casemate of the fortress, behind which, by stooping a little, a man of ordinary height could easily creep along unseen by the sentinel.

While pursuing his work of modelling in snow, the Marquis de Prerolles had taken care to observe the goings and comings of the civilian contractor, who, wearing a tall hat and attired in a black redingote, departed regularly every day at half-past four, carrying a large portfolio under his arm.  To procure such a costume and similar accessories for himself was easy, since the Marquis’s orderly spoke the language of the country; and to introduce them into the prison, hidden in a basket of provisions, was not difficult to accomplish.

To execute all this required only four trips to and fro.  At the end of forty-eight hours, the necessary aids to escape were in the proper place, hidden under the snow behind the bastion.  More than this, the clever Alsatian had slipped a topographical map of the surrounding country between two of the plates in the basket.  According to the scale, the frontier was distant only about five leagues, across open country, sparsely settled with occasional farms which would serve as resting-places.

By that time, the plan of escape was drawn up.  Upon the day fixed for his flight, the Marquis assumed his disguise, rolled up his own uniform to look like a man asleep in his bed, lying after the fashion of a sleeping soldier; and pleading a slight illness as an excuse for not dining that evening, and, not without emotion, curled himself up behind the snowy intrenchment which his jailer himself had helped to fashion.  That worthy man, only too glad to be able to rejoin his ‘liebe frau’ a little earlier than usual, peeped through the half-open door of the prisoner’s room and threw a glance at the little cot-bed.