Poirot shook his head.
'The case is not over, my friend. It will not be over until we find out who stole the pearls.'
'But the maid did!'
'Why do you say that? '
'Why,' I stammered, 'they were found - actually in her mattress.'
'Ta, ta, ta!' said Poirot impatiently. 'Those were not the pearls.'
'What?'
'Imitation, mon ami.'
The statement took my breath away. Poirot was smiling placidly.
'The good inspector obviously knows nothing of jewels. But presently there will be a fine hullabaloo!'
'Come!' I cried, dragging at his arm.
'Where?'
'We must tell the Opalsens at once.'
'I think not.'
'But that poor woman - '
'Eh bien; that poor woman, as you call her, will have a much better night believing the jewels to be safe.'
'But the thief may escape with them!'
'As usual, my friend, you speak without reflection. How do you know that the pearls Mrs Opalsen locked up so carefully tonight were not the false ones, and that the real robbery did not take place at a much earlier date?'
'Oh! 'I said, bewildered.
'Exactly,' said Poirot, beaming. 'We start again.'
He led the way out of the room, paused a moment as though considering, and then walked down to the end of the corridor, stopping outside the small den where the chambermaids and valets of the respective floors congregated. Our particular chambermaid appeared to be holding a small court there, and to be retailing her late experiences to an appreciative audience. She stopped in the middle of a sentence. Poirot bowed with his usual politeness.
'Excuse that I derange you, but I shall be obliged if you will unlock for me the door of Mr Opalsen's room.'
The woman rose willingly, and we accompanied her down the passage again. Mr Opalsen's room was on the other side of the corridor, its door facing that of his wife's room. The chambermaid unlocked it with her pass-key, and we entered.
As she was about to depart Poirot detained her.
'One moment; have you ever seen among the effects of Mr Opalsen a card like this?'
He held out a plain white card, rather highly glazed and uncommon in appearance. The maid took it and scrutinized it carefully.
'No, sir, I can't say I have. But, anyway, the valet has most to do with the gentlemen's rooms.'
'I see. Thank you.'
Poirot took back the card. The woman departed. Poirot appeared to reflect a little. Then he gave a short, sharp nod of the head.
'Ring the bell, I pray of you, Hastings. Three times, for the valet.'
I obeyed, devoured with curiosity. Meanwhile Poirot had emptied the waste-paper basket on the floor, and was swiftly going through its contents.
In a few moments the valet answered the bell. To him Poirot put the same question, and handed him the card to examine. But the response was the same. The valet had never seen a card of that particular quality among Mr Opalsen's belongings. Poirot thanked him, and he withdrew, somewhat unwillingly, with an inquisitive glance at the overturned waste-paper basket and the litter on the floor. He could hardly have helped overhearing Poirot's thoughtful remark as he bundled the torn papers back again:
'And the necklace was heavily insured ... '
'Poirot,' I cried, 'I see - '
'You see nothing, my friend,' he replied quickly. 'As usual, nothing at all! It is incredible - but there it is. Let us return to our own apartments.'
We did so in silence. Once there, to my intense surprise, Poirot effected a rapid change of clothing.
'I go to London tonight,' he explained. 'It is imperative.'
'What?'
'Absolutely. The real work, that of the brain (ah, those brave little grey cells), it is done. I go to seek the confirmation. I shall find it!
Impossible to deceive Hercule Poirot!'
'You'll come a cropper one of these days,' I observed, rather disgusted by his vanity.
'Do not be enraged, I beg of you, mon ami. I count on you to do me a service - of your friendship.'
'Of course,' I said eagerly, rather ashamed of my moroseness.
'What is it?'
'The sleeve of my coat that I have taken off - will you brush it? See you, a little white powder has clung to it. You without doubt observed me run my finger round the drawer of the dressing-table?'
'No, I didn't.'
'You should observe my actions, my friend. Thus I obtained the powder on my finger, and, being a little overexcited, I rubbed it on my sleeve; an action without method which I deplore - false to all my principles.'
'But what was the powder?' I asked, not particularly interested in Poirot's principles.
'Not the poison of the Borgias,' replied Poirot, with a twinkle. 'I see your imagination mounting. I should say it was French chalk.'
'French chalk?'
'Yes, cabinet-makers use it to make drawers run smoothly.
I laughed.
'You old sinner! I thought you were working up to something exciting.'
'Au revoir, my friend. I save myself. I fly!'
The door shut behind him. With a smile, half of derision, half of affection, I picked up the coat and stretched out my hand for the clothes brush.
II
The next morning, hearing nothing from Poirot, I went out for a stroll, met some old friends, and lunched with them at their hotel. In the afternoon we went for a spin. A punctured tyre delayed us, and it was past eight when I got back to the Grand Metropolitan.
The first sight that met my eyes was Poirot, looking even more diminutive than usual, sandwiched between the Opalsens, beaming in a state of placid satisfaction.
'Mon ami Hastings!' he cried, and sprang to meet me. 'Embrace me, my friend; all has marched to a marvel!'
Luckily, the embrace was merely figurative - not a thing one is always sure of with Poirot.
'Do you mean - ' I began.
'Just wonderful, I call it!' said Mrs Opalsen, smiling all over her fat face. 'Didn't I tell you, Ed, that if he couldn't get back my pearls nobody would?'
'You did, my dear, you did. And you were right.'
I looked helplessly at Poirot, and he answered the glance.
'My friend Hastings is, as you say in England, all at the seaside.
Seat yourself, and I will recount to you all the affair that has so happily ended.'
'Ended?'
'But yes. They are arrested.'
'Who are arrested?'
'The chambermaid and the valet, parbleu ! You did not suspect? Not with my parting hint about the French chalk?'
'You said cabinet-makers used it.'
'Certainly they do - to make drawers slide easily. Somebody wanted that drawer to slide in and out without any noise. Who could that be? Obviously, only the chambermaid. The plan was so ingenious that it did not at once leap to the eye - not even to the eye of Hercule Poirot.
'Listen, this was how it was done. The valet was in the empty room next door, waiting. The French maid leaves the room. Quick as a flash the chambermaid whips open the drawer, takes out the jewelcase and, slipping back the bolt, passes it through the door. The valet opens it at his leisure with the duplicate key with which he has provided himself, extracts the necklace, and waits his time.
Célestine leaves the room again, and - pst! - in a flash the case is passed back again and replaced in the drawer.
'Madame arrives, the theft is discovered. The chambermaid demands to be searched, with a good deal of righteous indignation, and leaves the room without a stain on her character. The imitation necklace with which they have provided themselves has been concealed in the French girl's bed that morning by the chambermaid-a master stroke, ça !'
'But what did you go to London for?'
'You remember the card?'
'Certainly. It puzzled me - and puzzles me still. I thought - '
I hesitated delicately, glancing at Mr Opalsen.
Poirot laughed heartily.
'Une blague! For the benefit of the valet. The card was one with a specially prepared surface - for fingerprints. I went straight to Scotland Yard, asked for our old friend Inspector Japp, and laid the facts before him. As I had suspected, the fingerprints proved to be those of two well-known jewel thieves who have been "wanted" for some time. Japp came down with me, the thieves were arrested, and the necklace was discovered in the valet's possession. A clever pair, but they failed in method. Have I not told you, Hastings, at least thirty-six times, that without method - '