Anne Morisot had told you that she herself was going to England by train; you never expected her to be on the plane, and it seriously jeopardized your plans.
If it was once known that Giselle's daughter and heiress had been on the plane, suspicion would naturally have fallen upon her.
Your original idea was that she should claim the inheritance with a perfect alibi, since she would have been on a train or a boat at the time of the crime!
And then you would have married her.
"The girl was by this time infatuated with you. But it was money you were after, not the girl herself.
"There was another complication to your plans.
At Le Pinet you saw Mademoiselle Jane Grey and fell madly in love with her.
Your passion for her drove you on to play a much more dangerous game.
"You intended to have both the money and the girl you loved.
You were committing a murder for the sake of money and you were in no mind to relinquish the fruits of the crime.
You frightened Anne Morisot by telling her that if she came forward at once to proclaim her identity, she would certainly be suspected of the murder. Instead you induced her to ask for a few days' leave and you went together to Rotterdam, where you were married.
"In due course you primed her how to claim the money.
She was to say nothing of her employment as lady's maid and it was very clearly to be made plain that she and her husband had been abroad at the time of the murder.
"Unfortunately, the date planned for Anne Morisot to go to Paris and claim her inheritance coincided with my arrival in Paris where Miss Grey had accompanied me.
That did not suit your book at all.
Either Mademoiselle Jane or myself might recognize in Anne Morisot the Madeleine who had been Lady Horbury's maid.
"You tried to get in touch with her in time, but failed.
You finally arrived in Paris yourself and found she had already gone to the lawyer.
When she returned, she told you of her meeting with me.
Things were becoming dangerous and you made up your mind to act quickly.
"It had been your intention that your new-made wife should not survive her accession to wealth very long.
Immediately after the marriage ceremony, you had both made wills leaving all you had one to the other!
A very touching business.
"You intended, I fancy, to follow a fairly leisurely course.
You would have gone to Canada - ostensibly because of the failure of your practice.
There you would have resumed the name of Richards and your wife would have rejoined you.
All the same, I do not fancy it would have been very long before Mrs Richards regrettably died, leaving a fortune to a seemingly inconsolable widower.
You would then have returned to England as Norman Gale, having had the good fortune to make a lucky speculation in Canada!
But now you decided that no time must be lost."
Poirot paused and Norman Gale threw back his head and laughed.
"You are very clever at knowing what people intend to do!
You ought to adopt Mr Clancy's profession!" His tone deepened to one of anger: "I never heard such a farrago of nonsense.
What you imagined, M. Poirot, is hardly evidence!"
Poirot did not seem put out.
He said: "Perhaps not. But then I have some evidence."
"Really?" sneered Norman. "Perhaps you have evidence as to how I killed old Giselle when everyone in the aeroplane knows perfectly well I never went near her?"
"I will tell you exactly how you committed the crime," said Poirot. "What about the contents of your dispatch case?
You were on a holiday. Why take a dentist's linen coat?
That is what I asked myself. And the answer is this: Because it resembled so closely a steward's coat. "This is what you did: When coffee was served and the stewards had gone to the other compartment, you went to the wash room, put on your linen coat, padded your cheeks with cotton-wool rolls, came out, seized a coffee spoon from the box in the pantry opposite, hurried down the gangway with the steward's quick run, spoon in hand, to Giselle's table. You thrust the thorn into her neck, opened the match box and let the wasp escape, hurried back into the wash room, changed your coat and emerged leisurely to return to your table.
The whole thing took only a couple of minutes.
"Nobody notices a steward particularly.
The only person who might have recognized you was Mademoiselle Jane, but you know women!
As soon as a woman is left alone - particularly when she is traveling with an attractive young man - she seizes the opportunity to have a good look in her hand mirror, powder her nose and adjust her make-up."
"Really," sneered Gale, "a most interesting theory, but it didn't happen.
Anything else?"
"Quite a lot," said Poirot. "As I have just said, in the course of conversation a man gives himself away. You were imprudent enough to mention that for a while you were on a farm in South Africa.
What you did not say, but what I have since found out, is that it was a snake farm."
For the first time, Norman Gale showed fear.
He tried to speak, but the words would not come.
Poirot continued: