However, I am not the man to act on impulse, even at a moment like this.  I wanted to think the whole matter over first, and . . . well . . .  I had made up my mind to demand five thousand francs when I handed the document over to my first client to-morrow morning.  At any rate, for the moment I acted—­if I may say so—­with great circumspection and dignity.

“I must presume, Mademoiselle,” I said in my most business-like manner, “that the document you speak of has been stolen.”

“Stolen, Monsieur,” she assented whilst the tears once more gathered in her eyes, “and M. de Marsan now lies at death’s door with a terrible attack of brain fever, brought on by shock when he discovered the loss.”

“How and when was it stolen?” I asked.

“Some time during the morning,” she replied.  “M. de Talleyrand gave the document to M. de Marsan at nine o’clock, telling him that he wanted the copy by midday.  M. de Marsan set to work at once, laboured uninterruptedly until about eleven o’clock, when a loud altercation, followed by cries of ‘Murder!’ and of ‘Help!’ and proceeding from the corridor outside his door, caused him to run out of the room in order to see what was happening.  The altercation turned out to be between two men who had pushed their way into the building by the main staircase, and who became very abusive to the gendarme who ordered them out.  The men were not hurt; nevertheless they screamed as if they were being murdered.  They took to their heels quickly enough, and I don’t know what has become of them, but . . .”

“But,” I concluded blandly, “whilst M. de Marsan was out of the room the precious document was stolen.”

“It was, Monsieur,” exclaimed Mlle. Geoffroy piteously.  “You will find it for us . . . will you not?”

Then she added more calmly:  “My brother and I are offering ten thousand francs reward for the recovery of the document.”

I did not fall off my chair, but I closed my eyes.  The vision which the lovely lady’s words had conjured up dazzled me.

“Mademoiselle,” I said with solemn dignity, “I pledge you my word of honour that I will find the document for you and lay it at your feet or die in your service.  Give me twenty hours, during which I will move heaven and earth to discover the thief.  I will go at once to the Chancellerie and collect what evidence I can.  I have worked under M. de Robespierre, Mademoiselle, under the great Napoleon, and under the illustrious Fouche!  I have never been known to fail, once I have set my mind upon a task.”

“In that case you will earn your ten thousand francs, my friend,” said the odious Arthur drily, “and my sister and M. de Marsan will still be your debtors.  Are there any questions you would like to ask before we go?”

“None,” I said loftily, choosing to ignore his sneering manner.  “If Mademoiselle deigns to present herself here to-morrow at two o’clock I will have news to communicate to her.”