“That is excellent, Emil,” Mr. Sabin said.  “Now there is one more question—­quite a harmless one.  Annette spoke of my life being in some way insured.”

“It is true, monsieur,” Emil admitted.  “A lady who also possessed the yellow crayon came here the day that—­that monsieur incurred the displeasure of—­of his friends.  She tried to bribe me to blow up my laboratory and leave the country, or that I should substitute a harmless powder for any required by the Prince.  I was obliged to refuse.”

“And then?”

“Then she promised me a large sum if you were alive in six months, and made me at once a payment.

“Dear me,” Mr. Sabin said, “this is quite extraordinary.”

“I can tell monsieur the lady’s name,” Emil continued, “for she raised her veil, and everywhere the illustrated papers have been full of her picture.  It was the lady who was besieged in a little town of South Africa, and who carried despatches for the general, disguised as a man.”

“Lady Carey!” Mr. Sabin remarked quietly.

“That was the lady’s name,” Emil agreed.

Mr. Sabin was thoughtful for a few moments.  Then he looked up.

“Emil Sachs,” he said sternly, “you have given out at least one portion of your abominable concoction which is meant to end my days.  Whether I shall escape it or not remains to be seen.  I am forced at the best to discharge my servant, and to live the life of a hunted man.  Now you have done enough mischief in the world.  To-morrow morning a messenger will place in your hands two hundred pounds.  A larger sum will await you at Baring’s Bank in New York.  You will go there and buy a small restaurant in the business quarter.  This is your last chance, Emil.  I give it to you for the sake of Annette.”

“And I accept it, monsieur, with gratitude.”

“For the present "

Mr. Sabin stopped short.  His quick ears had caught the swish of woman’s gown passing along the passage outside.  Emil too had heard it.

“It is the dark lady,” he whispered, “who purchased from me the other powder.  See, I open gently this door.  Monsieur must both see and hear.”

The door at the end of the passage was opened.  A woman stepped out into the little bar and made her way towards the door.  Here she was met by a man entering.  Mr. Sabin held up his forefinger to stop the terrified exclamation which trembled on Emil’s lips.  The woman was Lucille, the man the Prince.  It was Lucille who was speaking.

“You have followed me, Prince.  It is intolerable.”

“Dear Lucille, it is for your own sake.  These are not fit parts for you to visit alone.”

“It is my own business,” she answered coldly.

The Prince appeared to be in a complaisant mood.

“Come,” he said, “the affair is not worth a quarrel.  I ask you no questions.  Only since we are here I propose that we test the cooking of the good Annette.  We will lunch together.”