“Were the sums large?”

“Latterly, on an average about 10,000 francs a month.”

“And how were they paid?”

“Sometimes I sent the amount in cash, often by cheque on Brussels banks.”

“Have you any evidence on the point—­a receipt signed by the Countess?”

Amelungen hesitated.

“I strongly advise you to keep nothing back from me.  So much is at stake for you and your relatives who are involved in this affair that it is of the utmost consequence that you should secure lenient treatment by a frank confession.”

“Well, then, I have some receipts.”

“Please let me see them.”

Amelungen pulled open a drawer in his writing-table, pressed a spring, and a secret compartment at the back flew open.

“There they are!” said he, handing a small bundle of sheets of paper to Heideck.  But the Major’s keen eye had noticed, as he glanced rapidly at the compartment, that it contained some other papers, which he politely but firmly demanded to see.

“They are private letters of no importance,” objected Amelungen, “some of my wife’s correspondence, which she accidentally left in my office.  I don’t know what they are about myself.”

“Be assured that harmless private correspondence will not be abused.  But I must claim the absolute right to convince myself of the correctness of your assertions by examining them.”

The merchant could see that there was no chance of getting out of it, and, visibly excited, handed the little roll over to Heideck.

The Major took it, without examining the contents more closely at once.

“You definitely assure me, Herr Amelungen, that you have nothing else referring to this matter?”

“Nothing!  I give you my word, Herr major.”

Heideck got up.

“I charge you not to attempt to leave the town or in any other way evade the German authorities.  You will guarantee this not only as regards yourself, but also as regards your wife; and you will further promise me to break off at once all relations with the persons involved in this espionage affair, unless at our order, or in agreement with us.”

Eberhard Amelungen, whose powers of resistance seemed completely broken in this painful hour, nodded assent.

“I promise both, Herr major!”

Heideck, having left a criminal official with instructions to keep watch, repaired without delay to the office of Lieutenant-Colonel Nollenberg, head of the intelligence department for Antwerp.  He informed him of the result of his conversation and examined the confiscated papers in his presence.

A large number were letters from the Countess Clementine Arselaarts to Frau Beatrix Amelungen, and their contents were harmless, with the exception of a few expressions advising watchfulness and despatch.

But in a special envelope, sealed several times, there was a sheet of paper, covered with close writing, which could not be read offhand, since the letters were apparently jumbled together quite arbitrarily and irregularly.