Gentleman Jack had lowered his revolver, and was standing waitingto explain all, with the insufferable look of the man who is justgoing to say that he has only done his duty and requires nothanks.

　　"Who are you?" he said.

　　"Nev' min' who I am!" said Miss Trimble curtly. "Siz Pett knowswho I am.""I hope you won't be offended, Lord Wisbeach," said Mrs. Pettfrom the group by the door. "I engaged a detective to help you. Ireally thought you could not manage everything by yourself. Ihope you do not mind.""Not at all, Mrs. Pett. Very wise.""I'm so glad to hear you say so.""An excellent move."Miss Trimble broke in on these amiable exchanges.

　　"Whassall this? Howjer mean--help me?""Lord Wisbeach most kindly offered to do all he could to protectmy nephew's explosive," said Mrs. Pett.

　　Gentleman Jack smiled modestly.

　　"I hope I have been of some slight assistance! I think I camedown in the nick of time. Look!" He pointed to the safe. "He hadjust got it open! Luckily I had my pistol with me. I covered him,and called for help. In another moment he would have got away."Miss Trimble crossed to the safe and inspected it with a frown,as if she disliked it. She gave a grunt and returned to her placeby the window.

　　"Made good job 'f it!" was her comment.

　　Ann came forward. Her face was glowing and her eyes shone.

　　"Do you mean to say that you found Jimmy breaking into the safe?

　　I never heard anything so absurd!"Mrs. Pett intervened.

　　"This is not James Crocker, Ann! This man is an impostor, whocame into the house in order to steal Willie's invention." Shelooked fondly at Gentleman Jack. "Lord Wisbeach told me so. Heonly pretended to recognise him this afternoon."A low gurgle proceeded from the open mouth of little Ogden. Theproceedings bewildered him. The scene he had overheard in thelibrary between the two men had made it clear to him that Jimmywas genuine and Lord Wisbeach a fraud, and he could notunderstand why Jimmy did not produce his proofs as before. He wasnot aware that Jimmy's head was only just beginning to clear fromthe effects of the blow on the chin. Ogden braced himself forresolute lying in the event of Jimmy calling him as a witness.

　　But he did not intend to have his little business propositiondragged into the open.

　　Ann was looking at Jimmy with horror-struck eyes. For the firsttime it came to her how little she knew of him and how verylikely it was--in the face of the evidence it was almostcertain--that he should have come to the house with the intentionof stealing Willie's explosive. She fought against it, but avoice seemed to remind her that it was he who had suggested theidea of posing as Jimmy Crocker. She could not help rememberinghow smoothly and willingly he had embarked on the mad scheme.

　　But had it been so mad? Had it not been a mere cloak for thisother venture? If Lord Wisbeach had found him in this room, withthe safe blown open, what other explanation could there be?

　　And then, simultaneously with her conviction that he was acriminal, came the certainty that he was the man she loved. Ithad only needed the spectacle of him in trouble to make her sure.

　　She came to his side with the vague idea of doing something tohelp him, of giving him her support. Once there, she found thatthere was nothing to do and nothing to say. She put her hand onhis, and stood waiting helplessly for she knew not what.

　　It was the touch of her fingers which woke Jimmy from his stupor.

　　He came to himself almost with a jerk. He had been mistily awareof what had been said, but speech had been beyond him. Now, quitesuddenly, he was a whole man once more. He threw himself into thedebate with energy.

　　"Good Heavens!" he cried. "You're all wrong. I found _him_ blowingopen the safe!"Gentleman Jack smiled superciliously.

　　"A likely story, what! I mean to say, it's a bit thin!""Ridiculous!" said Mrs. Pett. She turned to Miss Trimble with agesture. "Arrest that man!""Wait a mom'nt," replied that clear-headed maiden, picking herteeth thoughtfully with the muzzle of her revolver. "Wait mom'nt.

　　Gotta look 'nto this. Hear both these guys' st'ries.""Really," said Gentleman Jack suavely, "it seems somewhatabsurd--""Ney' mind how 'bsurd 't sounds," returned the fair Trimblerebukingly. "You close y'r face 'n lissen t' me. Thass all you'vegotta do.""I know you didn't do it!" cried Ann, tightening her hold onJimmy's arm.

　　"Less 'f it, please. Less 'f it!" Miss Trimble removed the pistolfrom her mouth and pointed it at Jimmy. "What've you to say? Talkquick!""I happened to be down there--""Why?" asked Miss Trimble, as if she had touched off a bomb.

　　Jimmy stopped short. He perceived difficulties in the way ofexplanation.

　　"I happened to be down there," he resumed stoutly, "and that mancame into the room with an electric torch and a blowpipe andbegan working on the safe--"The polished tones of Gentleman Jack cut in on his story.

　　"Really now, is it worth while?" He turned to Miss Trimble. "I camedown here, having heard a noise. I did not _happen_ to be here forsome unexplained purpose. I was lying awake and something attractedmy attention. As Mrs. Pett knows, I was suspicious of this worthyand expected him to make an attempt on the explosive at any moment:

　　so I took my pistol and crept downstairs. When I got here, the safewas open and this man making for the window."Miss Trimble scratched her chin caressingly with the revolver,and remained for a moment in thought. Then she turned to Jimmylike a striking rattlesnake.

　　"Y' gotta pull someth'g better th'n that," she said. "I got y'rnumber. Y're caught with th' goods.""No!" cried Ann.

　　"Yes!" said Mrs. Pett. "The thing is obvious.""I think the best thing I can do," said Gentleman Jack smoothly,"is to go and telephone for the police.""You think of everything, Lord Wisbeach," said Mrs. Pett.

　　"Not at all," said his lordship.

　　Jimmy watched him moving to the door. At the back of his mindthere was a dull feeling that he could solve the whole trouble ifonly he could remember one fact which had escaped him. Theeffects of the blow he had received still handicapped him. Hestruggled to remember, but without result. Gentleman Jack reachedthe door and opened it: and as he did so a shrill yapping,hitherto inaudible because of the intervening oak and the raisedvoices within, made itself heard from the passage outside.

　　Gentleman Jack closed the door with a hasty bang.

　　"I say that dog's out there!" he said plaintively.

　　The scratching of Aida's busy feet on the wood bore out hiswords. He looked about him, baffled.

　　"That dog's out there!" he repeated gloomily.

　　Something seemed to give way in Jimmy's brain. The simple factwhich had eluded him till now sprang into his mind.

　　"Don't let that man get out!" he cried. "Good Lord! I've onlyjust remembered. You say you found me breaking into the safe!

　　You say you heard a noise and came down to investigate! Well,then, what's that test-tube of the explosive doing in yourbreast-pocket?" He swung round to Miss Trimble. "You needn't takemy word or his word. There's a much simpler way of finding outwho's the real crook. Search us both." He began to turn out hispockets rapidly. "Look here--and here--and here! Now ask him todo the same!"He was pleased to observe a spasm pass across Gentleman Jack'shitherto composed countenance. Miss Trimble was eyeing the latterwith sudden suspicion.

　　"Thasso!" she said. "Say, Bill, I've f'gott'n y'r name--'sup toyou to show us! Less've a look 't what y' got inside there."Gentleman Jack drew himself up haughtily.

　　"I really could not agree to--"Mrs. Pett interrupted indignantly.

　　"I never heard of such a thing! Lord Wisbeach is an old friend--""Less'f it!" ordered Miss Trimble, whose left eye was now likethe left eye of a basilisk. "Y' _gotta_ show us, Bill, so b'

　　quick 'bout 't!"A tired smile played over Gentleman Jack's face. He was the boredaristocrat, mutely protesting against something that "wasn'tdone." He dipped his slender fingers into his pocket. Then,drawing out the test-tube, and holding it up, he spoke with adrawling calm for which even Jimmy could not help admiring him.

　　"All right! If I'm done, I'm done!"The sensation caused by his action and his words was of the kindusually described as profound. Mrs. Pett uttered a strangledshriek. Willie Partridge yelped like a dog. Sharp exclamationscame simultaneously from each of the geniuses.

　　Gentleman Jack waited for the clamour to subside. Then he resumedhis gentle drawl.

　　"But I'm not done," he explained. "I'm going out now through thatwindow. And if anybody tries to stop me, it will be his--orher--" he bowed politely to Miss Trimble--"last act in the world.

　　If any one makes a move to stop me, I shall drop this test-tubeand blow the whole damned place to pieces."If his first speech had made a marked impression on his audience,his second paralysed them. A silence followed as of the tomb.

　　Only the yapping of the dog Aida refused to be stilled.

　　"Y' stay where y' are!" said Miss Trimble, as the speaker movedtowards the window. She held the revolver poised, but for thefirst time that night--possibly for the first time in herlife--she spoke irresolutely. Superbly competent woman though shewas, here was a situation that baffled her.

　　Gentleman Jack crossed the room slowly, the test-tube held aloftbetween fore-finger and thumb. He was level with Miss Trimble,who had lowered her revolver and had drawn to one side, plainly ata loss to know how to handle this unprecedented crisis, when thedoor flew open. For an instant the face of Howard Bemis, thepoet, was visible.

　　"Mrs. Pett, I have telephoned--"Then another voice interrupted him.

　　"Yipe! Yipe! Yipe!"Through the opening the dog Aida, rejoicing in the removal of theobstacle, raced like a fur muff mysteriously endowed with legsand............