ot know。 He deals with the highest in Europe and with the lowest of the riff…raff of the underworld。〃
Van Aldin was looking at Poirot with suddenly awakened attention。
〃Well？〃 he demanded； a new note in his voice。
〃I ask myself；〃 said Poirot； 〃I； Hercule Poirot …〃 he thumped himself dramatically on the chest … 〃ask myself why is M。 Papopolous suddenly e to Nice？〃
Van Aldin was impressed。 For a moment he had doubted Poirot and suspected the little man of being past his job； a poseur only … now； in a moment； he switched back to his original opinion。 He looked straight at the little detective。
〃I must apologize to you； M。 Poirot。〃
Poirot waved the apology aside with an extravagant gesture。
〃Bah！〃 he cried； 〃all that is of no importance。 Now listen； M。 Van Aldin； I have news for you。〃
The millionaire looked sharply at him； all his interest aroused。
Poirot nodded。
〃It is as I say。 You will be interested。 As you know； M。 Van Aldin； the te de la Roche has been under surveillance ever since his interview with the Juge d'Instruction。 The day after that； during his absence； the Villa Marina was searched by the police。〃
〃Well；〃 said Van Aldin； 〃did they find anything？ I bet they didn't。〃
Poirot made him a little bow。
〃Your acumen is not at fault； M。 Van Aldin。 They found nothing of an incriminating nature。 It was not to be expected that they would。 The te de la Roche； as your expressive idiom has it； was not born on the preceding day。 He is an astute gentleman with great experience。〃
〃Well； go on；〃 growled Van Aldin。
〃It may be； of course； that the te had nothing of a promising nature to conceal。 But we must not neglect the possibility。 If then； he has something to conceal； where is it？ Not in his house … the police searched thoroughly。 Not on his person； for he knows that he is liable to arrest at any minute。 There remains … his car。 As I say； he was under surveillance。 He was followed on that day to Monte Carlo。 From there he went by road to Mentone； driving himself。 His car is a very powerful one； it outdistanced his pursuers and for about a quarter of an hour they pletely lost sight of him。〃
〃And during that time you think he concealed something by the roadside？〃 asked Van Aldin； keenly interested。
〃By the roadside； no。 ？a n'est pas pratique。 But listen now … me； I have made a little suggestion to M。 Carrege。 He is graciously pleased to approve of it。 In each Bureau de Poste in the neighbourhood it has been seen to that there is someone who knows the te de la Roche by sight。 Because； you see； Messieurs； the best way of hiding a thing is by sending it away by the post。〃
〃Well？〃 demanded Van Aldin； his face was keenly alight with interest and expectation。
〃Well …〃 With a dramatic flourish Poirot drew out from his pocket a loosely wrapped brown paper package from which the string had been removed。
〃During that quarter of an hour's interval； our good gentleman mailed this。〃
〃The address？〃 asked the other sharply。
Poirot nodded his head。
〃Might have told us something； but unfortunately it does not。 The package was addressed to one of these little newspaper shops in Paris where letters and parcels are kept until called for on payment of a small mission。〃
〃Yes； but what is inside？〃 demanded Van Aldin impatiently。
Poirot unwrapped the brown paper and disclosed a square cardboard box。 He looked round him。
〃It is a good moment；〃 he said quietly。 〃All eyes are on the tennis。 Look； Monsieur！〃
He lifted the lid of the box for the fraction of a second。 An exclamation of utter astonishment came from the millionaire。 His face turned as white as chalk。
〃My God！〃 he breathed； 〃the rubies。〃
He sat for a minute as though dazed。 Poirot restored the box to his pocket。 Then suddenly the millionaire seemed to e out of his trance； he leaned across to Poirot and wrung his hand so heartily that the little man winced with pain。
〃This is great；〃 said Van Aldin。 〃Great！ You are the goods； M。 Poirot。 Once and for all； you are the goods。〃
〃It is nothing；〃 said Poirot modestly。 〃Order； method； being prepared for eventualities beforehand … that is all there is to it。〃
〃And now； I suppose； the te de la Roche has been arrested？〃 continued Van Aldin eagerly。
〃No；〃 said Poirot。
A look of utter astonishment came over Van Aldin's face。
〃But why？ What more do you want？〃
〃The te's alibi is still unshaken。〃
〃But that is nonsense。〃
〃Yes；〃 said Poirot； 〃I rather think it is nonsense； but unfortunately we have to prove it so。〃
〃In the meantime he will slip through your fingers。〃
Poirot shook his head very energetically。
〃No；〃 he said； 〃he will not do that。 The one thing the te cannot afford to sacrifice is his social position。 At all costs he must stop and brazen it out。〃
Van Aldin was still dissatisfied。
〃But I don't see …〃
Poirot raised a hand。 〃Grant me a little moment； Monsieur。 Me； I have a little idea。 Many have mocked themselves at the little ideas of Hercule Poirot … and they have been wrong。〃
〃Well；〃 said Van Aldin； 〃go ahead。 What is this little idea？〃
Poirot paused for a moment and then he said：
〃I will call upon you at your hotel at eleven o'clock tomorrow morning。 Until then； say nothing to anyone。〃
Chapter 22
M。 PAPOPOULOS AT BREAKFAST
M。 Papopolous was at breakfast。 Opposite him sat his daughter； Zia。
There was a knock at the sitting…room door； and a chasseur entered with a card which he brought to Mr Papopolous。 The latter scrutinized it； raised his eyebrows； and passed it over to his daughter。
〃Ah！〃 said M。 Papopolous； scratching his left ear thoughtfully； 〃Hercule Poirot。 I wonder now。〃
Father and daughter looked at each other。
〃I saw him yesterday at the tennis；〃 said M。 Papopolous。 〃Zia； I hardly like this。〃
〃He was very useful to you once；〃 his daughter reminded him。
〃That is true；〃 acknowledged M。 Papopolous； 〃also he has retired from active work； so I hear。〃
These interchanges between father and daughter had passed in their own language。 Now M。 Papopolous turned to the chasseur and said in French：
〃Faites monter ce monsieur。〃
A few minutes later Hercule Poirot； exquisitely attired； and swinging a cane with a jaunty air； entered the room。
〃My dear M。 Papopolous。〃
〃My dear M。 Poirot。〃
〃And Mademoiselle Zia。〃 Poirot swept her a low bow。
〃You will excuse us going on with our breakfast；〃 said M。 Papopolous； pouring himself out another cup of coffee。 〃Your call is … ahem！ … a little early。〃
〃It is scandalous；〃 said Poirot； 〃but see you； I am pressed。〃
〃Ah！〃 murmured M。 Papopolous； 〃you are on an affair then？〃
〃A very serious affair；〃 said Poirot； 〃the death of Madame Kettering。〃
〃Let me see；〃 M。 Papopolous looked innocently up at the ceiling； 〃that was the lady who died on the Blue Train； was it not？ I saw a mention of it in the papers； but there's no suggestion of foul play。〃
〃In the interests of justice；〃 said Poirot； 〃it was thought best to suppress that fact。〃
There was a pause。
〃And in what way can I assist you； Mr Poirot？〃 asked the dealer politely。
〃Voilà；〃 said Poirot； 〃I shall e