three. One of them gives a list of the dates on which the mysterious letters were to appear."
"Oho!" said M. Desmalions. "That's a crushing piece of evidence against Florence Levasseur. And also it tells us where Don Luis got his list from."
Perenna listened with surprise: he had utterly forgotten this particular; and Gaston Sauverand had made no reference to it in his narrative. And yet it was a strange and serious detail. From whom had Florence received that list of dates?
"And what's on the other two sheets?" asked M. Desmalions.
Don Luis pricked up his ears. Those two other sheets had escaped his attention on the day of his interview with Florence in this room.
"Here is one of them," said Weber.
M. Desmalions took the paper and read:
"Bear in mind that the explosion is independent of the letters, and that it will take place at three o'clock in the morning."
"Yes," he said, "the famous explosion which Don Luis foretold and which is to accompany the fifth letter, as announced on the list of dates. Tush! We have plenty of time, as there have been only three letters and the fourth is due to-night. Besides, blowing up that house on the Boulevard Suchet would be no easy job, by Jove! Is that all?"
"Monsieur le Préfet," said Weber, producing the third sheet, "would you mind looking at these lines drawn in pencil and enclosed in a large square containing some
