I shot a quick glance at Mary. She was very pale, but smiling.
"I proceeded to reason on that assumption. Mrs. Cavendish is in her mother-in-law's room. We will say that she is seeking for something and has not yet found it. Suddenly Mrs. Inglethorp awakens and is seized with an alarming paroxysm. She flings out her arm, overturning the bed table, and then pulls desperately at the bell. Mrs. Cavendish, startled, drops her candle, scattering the grease on the carpet. She picks it up, and retreats quickly to Mademoiselle Cynthia's room, closing the door behind her. She hurries out into the passage, for the servants must not find her where she is. But it is too late! Already footsteps are echoing along the gallery which connects the two wings. What can she do? Quick as thought, she hurries back to the young girl's room, and starts shaking her awake. The hastily aroused household come trooping down the passage. They are all busily battering at Mrs. Inglethorp's door. It occurs to nobody that Mrs. Cavendish has not arrived with the rest, but--and this is significant--I can find no one who saw her come from the other wing." He looked at Mary Cavendish. "Am I right, madame?"
She bowed her head.
"Quite right, monsieur. You understand that, if I had thought I would do my husband any good by revealing these facts, I would have done so. But it did not seem to me to bear upon the question of his guilt or innocence."
"In a sense, that is correct, madame. But it cleared my mind of many misconceptions, and left me free to see other facts in their true significance."
"The will!" cried Lawrence. "Then it was you, Mary, who destroyed the will?"
She shook her head, and Poirot shook his also.
"No," he said quietly. "There is only one person who could possibly have destroyed that will--Mrs. Inglethorp herself!"
"Impossible!" I exclaimed. "She had only made it out that very afternoon!"
"Nevertheless, mon ami, it was Mrs. Inglethorp. Because, in no other way can you account for the fact that, on one of the hottest days of the year, Mrs. Inglethorp ordered a fire to be lighted in her room."
I gave a gasp. What idiots we had been never to think of that fire as being incongruous! Poirot was continuing: "The temperature on that day, messieurs, was 80 degrees in the shade. Yet Mrs. Inglethorp ordered a fire! Why? Because she wished to destroy something, and could think of no other way. You will remember that, in consequence of the War economics practiced at Styles, no waste paper was thrown away. There was therefore no means of destroying a thick document such as a will. The moment I heard of a fire being lighted in Mrs. Inglethorp's room, I leaped to the conclusion that it was to destroy some important document--possibly a will. So the discovery of the charred fragment in the grate was no surprise to me. I did not, of course, know at the time that the will in question had only been made this afternoon, and I will admit that, when I learnt that fact, I fell into a grievous error. I came to the conclusion that Mrs. Inglethorp's determination to destroy her will arose as a direct consequence of the quarrel she had that afternoon, and that therefore the quarrel took place after, and not before the making of the will.