The Secrets of Potsdam. William Le Queux

over a mirror a letter upon a small sheet of note-paper bearing the watermark of a bull's head.

      "That paper was made at a mill in the south of Devonshire, in England, destroyed by fire five years ago. Paper of that make cannot be obtained anywhere else in France," he declared.

      I at once realized how much patience must have been expended upon the inquiry, and said:

      "Then you have actually fixed the shop where the writer purchased his paper?"

      "Yes," he replied. "And we know that the newly-invented typewriter, a specimen one, was sold by the Maison Audibert, in Marseilles. The purchaser of the typewriter in Marseilles purchases his paper and envelopes at Lancry's, in the Boulevard Haussmann."

      "Splendid!" I said enthusiastically, for it was clear that the Baron, with the thousand-and-one secret agents at his beck and call, had been able, with the Professor's aid, to fix the source of the stationery. "But," I added, "what is wanted from me?" Why, I wondered, had His Majesty sent the Baron that photograph of Elise Breitenbach?

      "I want you to go with me to the central door of the 'Printemps' at four o'clock this afternoon, and we will watch Lancry's shop across the way," the Baron replied.

      This we did, and from four till six o'clock we stood, amid the bustle of foot passengers, watching the small stationer's on the opposite side of the boulevard, yet without result.

      Next day and the next I accompanied the prosperous cinema proprietor upon his daily vigil, but in vain, until his reluctance to tell me the reason why I had been sent to Paris annoyed me considerably.

      On the fifth afternoon, just before five o'clock, while we were strolling together, smoking and chatting, the Baron's eyes being fixed upon the door of the small single-fronted shop, I saw him suddenly start, and then make pretence of utter indifference.

      "Look!" he whispered beneath his breath.

      I glanced across and saw a young man just about to enter the shop.

      The figure was unfamiliar, but, catching sight of his face, I held my breath. I had seen that sallow, deep-eyed countenance before.