Quickly he caught up the blotter he had been using, and shook it over a sheet of carbon paper, for there had flashed into his mind a prompt suspicion as to the nature of that dust. That it had fallen from the blotter there could be no question, and he recalled distinctly that he had left the mysteriously missing note lying on that blotter when he and the colonel took their hasty departure. A moment or two gave him all the confirmation of his suspicion that he required, for under his vigorous shaking there sifted down on the dark surface several fragments, from a sixteenth to a thirty-second of an inch in diameter, on which he could plainly decipher indications of typewriting. Snatching up a reading glass belonging to the colonel, he bent over these to satisfy himself he had made no mistake; then straightened up, with a muttered expletive and a little, puzzled frown between the eyes. The glass brought out on one of the specks what appeared unquestionably the upper half of an “m”--and, what was more, the letter was slightly chipped on one side. Grail leaned over to subject the fragment to a second examination, and make sure that he had not been misled; then drew from his pocket the carbon copy of the note he had dictated to Schilder’s stenographer, and compared the two impressions. They were alike, defect and all, as two pennies struck from the same die. One was forced to the conclusion that they had been made by the same machine. Dropping his chin into his hand, the adjutant sat staring almost incredulously at the telltale speck in front of him. This knocked into smithereens the entire theory he had evolved as to the disappearance of Colonel Vedant, for, despite the pains he had taken to secure a copy of the note from Schilder’s typewriter, he had never really believed that the original summons had come from there. Now, however, he was driven to a fresh line of speculation. Recalling the foundry manager’s freely expressed insinuations, he arose half impatiently, and tested the two typewriting machines used at headquarters. There were, as he expected, no point of similarity shown with the copy of the note he had caused to be transcribed by Miss Griffin. The “m” on both machines was clear-cut and flawless; there was no indication of blurring on the “D.” Returning to the desk, he resumed his perplexed contemplation of the fragments on the sheet of carbon paper. It seemed certain that Schilder must have sent the decoy message, relying on its speedy disintegration to cover up his tracks. And right there another consideration arose to muddle him: How had this disintegration been accomplished? Hitherto he had been so intent on establishing the identity of these specks of typewriting with the missing message that he had not stopped to question the agency which could so quickly and thoroughly destroy a stout sheet of linen paper.