Walters has also mentioned the matter to me."

Sir Lyster then pa.s.sed on to the guests. They comprised Mrs. Selton, an aunt of Sir Lyster; Sir Jeffrey and Lady Trawlor, old friends of their hostess; Lady Whyndale and her two daughters. There were also Mr. Gerald Nash, M. P., and Mr. and Mrs. Richard Winnington, old friends of Sir Lyster and Lady Grayne.

"Later, I may require a list of the guests," said Malcolm Sage, when Sir Lyster had completed his account. "You said, I think, that the key of the safe was sometimes left in an accessible place?"

"Yes, in a drawer."

"So that anyone having access to the room could easily have taken a wax impression."

"Sir Lyster flushed slightly.

"There is no one----" he began.

"There is always a potential someone," corrected Malcolm Sage, raising his eyes suddenly and fixing them full upon Sir Lyster.

"The question is, Sage," broke in Mr. Llewellyn John tactfully, "what are we to do?"

"I should first like to see the inside of the safe and the dummy packet," said Malcolm Sage, rising. "No, I will open it myself if you will give me the key," he added, as Sir Lyster rose and moved over to the safe.

Taking the key, Malcolm Sage kneeled before the safe door and, by the light of an electric torch, surveyed the whole of the surface with keen-sighted eyes. Then placing the key in the lock he turned it, and swung back the door, revealing a long official envelope as the sole contents. This he examined carefully without touching it, his head thrust inside the safe.

"Is this the same envelope as that in which the doc.u.ment was enclosed?" he enquired, without looking round.

The three men had risen and were grouped behind Malcolm Sage, watching him with keen interest.

"It's the same kind of envelope, but----" began

Sir Lyster, when Lord Beamdale interrupted.

"It's the envelope itself," he said. "I noticed that the right-hand top corner was bent in rather a peculiar manner."

Malcolm Sage rose and, taking out the envelope, carefully examined the damaged corner, which was bent and slightly torn.

"Yes, it's the same," cried Mr. Llewellyn John. "I remember tearing it myself when putting in the doc.u.ment."

"How many leaves of paper were there?" enquired Malcolm Sage.

"Eight, I think," replied Sir Lyster.

"Nine," corrected Lord Beamdale. "There was a leaf in front blank but for the words, 'Plans Department.'"

"Have you another doc.u.ment from the same Department?" enquired Malcolm Sage of Sir Lyster.

"Several."

"I should like to see one."

Sir Lyster left the room, and Malcolm Sage removed the contents of the envelope. Carefully counting nine leaves of blank white foolscap, he bent down over the paper, with his face almost touching it.

When Sir Lyster re-entered with another doc.u.ment in his hand Malcolm Sage took it from him and proceeded to subject it to an equally close scrutiny, holding up to the light each sheet in succession.

"I suppose, Sir Lyster, you don't by any chance use scent?" enquired Malcolm Sage without looking up.

"Mr. Sage!" Sir Lyster was on his dignity.

"I see you don't," was Malcolm Sage's calm comment as he resumed his examination of the dummy doc.u.ment. Replacing it in the envelope, he returned it to the safe, closed the door, locked it, and put the key in his pocket.

"Well! what do you make of it?" cried Mr. Llewellyn John eagerly.

"We shall have to take the Postmaster-general into our confidence."

"Woldington!" cried Mr. Llewellyn John in astonishment. "Why."

Sir Lyster looked surprised, whilst Lord Beamdale appeared almost interested.

"Because we shall probably require his help."

"How?" enquired Sir Lyster.

"Well, it's rather dangerous to tamper with His Majesty's mails without the connivance of St. Martins-le-Grand," was the dry retort.

"But----" began Mr. Llewellyn John, when suddenly he stopped short.

Malcolm Sage had walked over to where his overcoat lay, and was deliberately getting into it.

"You're not going, Mr. Sage'?" Sir Lyster's granite-like control seemed momentarily to forsake him. "What do you advise us to do?"

"Get some sleep," was the quiet reply.

"But aren't you going to search for----?" He paused as Malcolm Sage turned and looked full at him.

"A search would involve the very publicity you are anxious to avoid," was the reply.

"But----" began Mr. Llewellyn John, when Malcolm Sage interrupted him.

"The only effective search would be to surround the house with police, and allow each occupant to pa.s.s through the cordon after having been stripped. The house would then have to be gone through; carpets and boards pulled up; mattresses ripped open; chairs----"

"I agree with Mr. Sage," said Sir Lyster, looking across at the Prime Minister coldly.

"Had I been a magazine detective I should have known exactly where to find the missing doc.u.ment," said Malcolm Sage. "As I am not"--he turned to Sir Lyster--"it will be necessary for you to leave a note for your butler telling him that you have dropped somewhere about the house the key of this safe, and instructing him to have a thorough search made for it. You might casually mention the loss at breakfast, and refer to an important doc.u.ment inside the safe which you must have on Monday morning. Perhaps the Prime Minister will suggest telephoning to town for a man to come down to force the safe should the key not be found."

Malcolm Sage paused. The others were gazing at him with keen interest.

"Leave the note unfolded in a conspicuous place where anyone can see it," he continued.

"I'll put it on the hall-table," said Sir Lyster.

Malcolm Sage nodded.