"We shall see. Here I sit, mon ami. We do not stir out this morning. We await events here."

It was at half-past eleven exactly that the summons

came. A. petit bleu. Poirot tore it open, then handed it to me. It was from Madame Olivier, the world-famous

scientist, whom we had visited yesterday in connection

with the Halliday case. It asked us to come out to Passy at once.

We obeyed the summons without an instant's delay.

Madame Olivier received us in the same small salon. I

was struck anew with the wonderful power of this

woman, with her long nun's face and burning eyes--this

brilliant successor of Becquerel and the Curies. She

came to the point at once.

"Messieurs, you interviewed me yesterday about the

disappearance of M. Halliday. I now learn that you

returned to the house a second time, and asked to see

my secretary, Inez Veroneau. She left the house with

you, and has not returned here since."

"Is that all, madame?"

"No, monsieur, it is not. Last night the laboratory was broken into, and several valuable papers and memoranda were stolen. The thieves had a try for something

more precious still, but luckily they failed to open

the big safe."

"Madame, these are the facts of the case. Your late secretary, Madame Veroneau, was really the Countess

Rossakoff, an expert thief, and it was she who was

responsible for the disappearance of M. Halliday. How

long had she been with you?"

"Five months, monsieur. What you say amazes me."

"It is true, nevertheless. These papers, were they easy to find? Or do you think an inside knowledge was

shown?"

66 Agatha Christie

"It is rather curious that the thieves knew exactly where to look. You think Inez--"

"Yes, I have no doubt that it was upon her information that they acted. But what is this precious thing that

the thieves failed to find? Jewels?"

Madame Olivier shook her head with a faint smile.

"Something much more precious than that, monsieur." She looked round her, then bent forward, lowering

her voice. "Radium, monsieur."

"Radium?"

"Yes, monsieur. I am now at the crux of my experiments. I possess a small portion of radium myself-more has been lent to me for the process I am at work upon. Small though the actual quantity is, it comprises a large amount of the world's stock and represents a value of millions of francs."

"And where is it?"

"In its leaden case in the big safe--the safe purposely appears to be of an old and worn-out pattern, but it is

really a triumph of the safe-makers' art. That is probably why the thieves were unable to open it."

"How long are you keeping this radium in your possession?"

"Only for two days more, monsieur. Then my experiments will be concluded."

Poirot's eyes brightened.

"And Inez Veroneau is aware of the fact? Good-then our friends will come back. Not a word of me to any one, madame. But rest assured, I will save your