The windows of the three apartments occupied by the workmen were not only guarded by strong iron bars, but possessed the additional security of external wire blinds of exceedingly small mesh. Each window admitted plenty of light, and could be raised to allow a free circulation of air, but it was seemingly quite impossible for any active communication to take place with the outside. The three rooms looked out over a small enclosed lawn, which was separated from the park by a brick wall surmounted by iron railings. All the fireplaces had been closed with bricks and mortar.
"You will see, sir," said the inspector, when he had called Brett's attention to these details, "that mysterious though the murders were, they were as nothing compared with the disappearance of the diamonds. Every person who came downstairs was most carefully and methodically searched each time he passed the constable on duty at the bottom. It may be admitted that a few small stones could be so secreted as to escape observation, but some of these stones were so large that such a notion is not to be thought of, whilst the size of the great diamond which Mr. Talbot christened the 'Hen's Egg' rendered its transference past the searchers beneath absolutely impossible. There was no humbug about the search, you will understand, Mr. Brett. People had to take their boots off, open their mouths, and hand over their hats, coats, sticks, or umbrellas for inspection. Every part of their clothing was scrutinised, and the contents of their pockets, money, watches, keys, and the rest, thoroughly examined. These were our orders, and they were strictly obeyed, Mr. Talbot himself being the first to insist that the regulation should be carried out rigidly, so far as he was concerned. Why, one day a Cabinet Minister came here to see the diamonds. He was elderly and stout, and did not at all like having to take off his boots, I can assure you, as he nearly got apoplexy whilst lacing them up again."
During the inspector's running comments Brett had carefully scrutinised each of the windows. He at once came to the conclusion, by a simple analysis of the possibilities, that by no other means than through the barrier of iron wire had the diamonds passed out of the house; but the most thorough examination failed to reveal any loophole by which this achievement had been accomplished. He opened each of the windows, tested every iron bar, and saw that the fastenings of the external blind were undisturbed, whilst the fine wire mesh showed no irregularities in its hexagonal pattern wherein any defect would at once be visible.
"We have done all that long since, sir," said the second police officer, smiling at the obviousness of an amateur's method of inspection, for it happened that he had never met the barrister before, though he had often heard of him.
"You have?" said Brett, with the slightest tinge of sarcasm in his voice. "Did you do this?" and he commenced to thump with a clenched fist upon every portion of the external screen that he could reach.
"No, we did not," said the policeman, "and I don't see that it is going to accomplish anything except hurt your hand."
"That may be so," murmured Brett; "but the diamonds went this way and none other."
He tested every portion of one window screen in this manner without effect. Then he approached the second window, and, beginning at the left-hand top corner, did the same thing. Suddenly an exclamation came from the three interested watchers. In the centre of the lower part of the screen Brett's hand made a visible impression upon the iron wire. Using no more force than had been applied to other portions, the blow served to tear a section of the blind about eight inches across. Instantly the barrister ceased operations, and, producing a pocket-microscope, minutely examined the rent.
"I expected as much," he said, taking hold of the torn part of the screen and giving it a vigorous pull, with the result that a small piece, measuring about eight inches by six, came bodily out. "This has been cut away, as you will see, by some instrument which did not even bend the wire. It was subsequently replaced, whilst the fractured parts were sufficiently cemented by some composition to retain this section in its place, and practically defy observation. There was nothing for it but force to reveal it thus early. No doubt in time the composition would have dried, or been washed away, and then this bit of the screen would have fallen out by the action of wind and weather. Here, at any rate, is a hole in your defensive armour." He held out the pièce de conviction to the discomfited Sharpe, who surveyed it in silence.