On the morrow Verhoeff took pains to inform himself of the name of the sentinel at that place, and was not astonished to find that he was of Mynheer Volmar's household. In that time of trouble every man, whatsoever his rank and condition, had his part in the city's defence.
From that day Verhoeff kept diligent watch upon the councillor, and discovered that he hied him stealthily to the ramparts every Wednesday, and in like manner let down what was doubtless a paper, the which was received by a man in the moat beneath, and conveyed by him, swimming, to the further side.
Here was treason, of a surety. Verhoeff debated with himself whether he should broach it to the Captain of the Guard or the Burgomaster; but he bethought him that he had not as yet sufficient proof, and that, moreover, the charge might be set down to the spleen and malice of a beaten rival. Wherefore he determined to hold his peace until he had gotten some clear and manifest proof of the treason he suspected.
One Wednesday night, therefore, he slid into the moat, and swam to the other side, intending to lie in wait for the receiver as he returned with the letter, and wrest it from him. But making wary approach to the spot over against the gun whereon Volmar was wont to sit, he was nonplussed to find three or four Spanish footmen, awaiting their comrade. Verhoeff kept himself close until the swimmer joined them, and then, recking nothing of his peril, followed the party as they stole silently back to their lines. While they jested with the sentinel that challenged them, he crept into the camp, and watched in secret what should befall. The footmen proceeded together a few paces; then all but one turned aside, they bidding him good-night, and he continuing on his way towards a large tent, the which, after a brief parley with some one within, he entered. Verhoeff swiftly stole to the back side of the tent, designing to cut a hole in the wall and spy upon what was done; but a light shone from beneath a flap in the canvas, which raising, he beheld a man in shirt and hose sodden with water, standing before another in a long night-robe, who was reading by the light of a candle a paper which had beyond doubt been brought by the swimmer from the city. Having finished his perusal, this man said--