“A necessary precaution, Count.”

“Necessary, as you observe, Mr. Director. It is better for the peace of the world that his secret should die with him.”

After having glanced at the Count d’Artigas, Gaydon had not uttered a word; but preceding the two strangers he walked towards the clump of trees where the inventor was pacing back and forth.

Thomas Roch paid no attention to them. He appeared to be oblivious of their presence.

Meanwhile, Captain Spade, while being careful not to excite suspicion, had been minutely examining the immediate surroundings of the pavilion and the end of the park in which it was situated. From the top of the sloping alleys he could easily distinguish the peak of a mast which showed above the wall of the park. He recognized the peak at a glance as being that of the Ebba, and knew therefore that the wall at this part skirted the right bank of the Neuse.

The Count d’Artigas’ whole attention was concentrated upon the French inventor. The latter’s health appeared to have suffered in no way from his eighteen months’ confinement; but his queer attitude, his incoherent gestures, his haggard eye, and his indifference to what was passing around him testified only too plainly to the degeneration of his mental faculties.

At length Thomas Roch dropped into a seat and with the end of a switch traced in the sand of the alley the outline of a fortification. Then kneeling down he made a number of little mounds that were evidently intended to represent bastions. He next plucked some leaves from a neighboring tree and stuck them in the mounds like so many tiny flags. All this was done with the utmost seriousness and without any attention whatever being paid to the onlookers.

It was the amusement of a child, but a child would have lacked this characteristic gravity.

“Is he then absolutely mad?” demanded the Count d’Artigas, who in spite of his habitual impassibility appeared to be somewhat disappointed.

“I warned you, Count, that nothing could be obtained from him.”